Trainee Research Forum

Trainee Research

Forum Thursday, June 16 2016

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Celebrating Excellence in Our Talented Research Community Thursday, June 16 Welcome to the 16th annual Trainee Research Forum. Each year we host this event to showcase unique and innovative research being conducted by research and clinical trainees on the Oak Street campus.

The research community at BC Children’s Hospital provides trainees with a true ‘bench to bedside’ opportunity for research. We provide research training opportunities for graduate students, postdoctoral fellows, clinical residents and sub-specialty fellows throughout the year, and for undergraduate and medical students through our flagship Summer Student Research Program.

The diversity of the research here is remarkable, and the Trainee Research Forum provides a wonderful preview of the interdisciplinary work our trainees will pursue as they progress into their own careers as scientific and clinical investigators.

We are proud of the trainees here and we are pleased to be able to help them become leaders in their respective fields.

Wyeth W. Wasserman, Ph.D.

Poster Presentations 1:00pm Chieng Family Atrium Awards Ceremony & Reception 2:45pm Chan Centre for Family Health Education The ceremony will include the recipients of the following 2016 research awards • Trainee Outstanding Achievement Awards • Studentships & Fellowships • Poster Presentation Finalists • Geoffry L. Hammond Lectureship The ceremony will also feature a talk by Dr. Bruce Verchere, 2016 Geoffrey L. Hammond Lectureship recipient, on his career and research highlights

Executive Director, Research Institute, BC Children’s Hospital Associate Dean, Research, Faculty of Medicine, University of British Columbia

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Join us in celebrating the accomplishments of our colleagues and the positive impact of research taking place on the Oak Street campus Outstanding Achievement by a Masters Student Olivia de Goede Supervisor: Wendy Robinson This award recognizes the outstanding achievement of a masters student whose research skills and analytical capacity clearly demonstrate the individual’s potential as a productive member of the scientific community

Outstanding Achievement by a Doctoral Candidate Crystal Karakochuk Supervisor: Tim Green This award recognizes the outstanding achievement of a doctoral candidate whose demonstrated originality, research ability and a capacity for critical thinking identify the individual as being likely to become a contributing member in the scientific community

Outstanding Achievement by a Postdoctoral Fellow Folefac Aminkeng Supervisor: Michael Hayden This award recognizes the outstanding achievement of a postdoctoral fellow whose high academic achievements, personal leadership qualities and demonstrated research ability shows promise of the individual becoming a future leader in health research

Outstanding Achievement by a Resident Rebecca Ronsley Supervisor: Dina Panagiotopoulos This award recognizes the outstanding achievement of a resident whose scholarly activity, industry and commitment to the research endeavor are an example to other trainees and who have contributed to advances in child, youth and women’s health 3

Geoffrey L. Hammond Lectureship Bruce Verchere For outstanding accomplishments and long-standing excellence in research to benefit the health of children and families Bruce Verchere was instrumental in developing the vision, resources and infrastructure that enabled the creation of the Diabetes Program onsite.

Thanks to his dedication to fundraising and recruitment, the program is now

a thriving group of 22 dynamic, well-funded and collaborative investigators.He has also excelled as a mentor and guided the development of exciting new technologies within his research program. His trainees have improved the patient care landscape of British Columbia and his research advances promise to improve the life of individuals with diabetes. Beyond the Oak Street campus, he has taken leadership positions in government and non-government associations across the continent in order to protect funding for research and communicate the critical importance of health research to the community.

Studentships & Fellowships These training awards recognize highly qualified individuals who wish to pursue a research career in any health related research area that has direct relevance to improving the health of children and families Graduate Studentship Justin Chan (Kevan Jacobson) Michael Cuccione Childhood Cancer Foundation Graduate Studentship Mario Fidanza (Gregor Reid) Graduate Studentship Zhengcheng (Leo) He (Christopher Maxwell) Sue Carruthers Graduate Studentship Romy Hoeppli (Megan Levings) Canucks for Kids Fund Childhood Diabetes Laboratories Graduate Studentship Avery Lam (Megan Levings) Graduate Studentship Nicole Sanford (Todd Woodward) Jan M. Friedman Graduate Studentship Shawn Whitfield (Elizabeth Conibear) Healthy Starts Graduate Studentship Mahdi Yousefi (Guy Dumont)

Mining for Miracles Postdoctoral Fellowship Mohamed Elgendi (Kenneth Lim) Postdoctoral Fellowship Allison Matthews (Clara van Karnebeek) M.I.N.D Postdoctoral Fellowship Alexander Weber (Alexander Rauscher) Bertram Hoffmeister Postdoctoral Fellowship Matthew Wiens (Mark Ansermino & Guy Dumont) Scholars of Excellence Program Fellowship Sarah Moore (Michael Kobor & Tim Oberlander) Scholars of Excellence Program Fellowship Robert Selles (Evelyn Stewart) 4

Table of Contents Poster Presentations Showcasing the outstanding work of research trainees and clinical residents or subspecialty fellows and their contributions to research.

Session One – Masters Students Participant

Abstract Title

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Karen Davies Cassandra Dawson

Long-term follow-up of children with idiopathic toe walking PTP regulates focal adhesion dynamics and cell polarity to coordinate cell migration Placental MTHFR 677C>T genotypes in pregnancy pathologies The role of insulin-like growth factor-1 in programming of offspring adiposity by maternal folate/ vitamin B12 imbalance Expression and induction of amphiregulin in human regulatory T cells Altered crossover distribution and distance to telomeres in spermatocytes of infertile men Myt3 protects islet cells from glucotoxic cell death by suppressing Bim

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Giulia Del Gobbo Amanda Henderson Avery Lam He Ren Ben Vanderkruk

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Session Two – Masters Students Participant

Abstract Title

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Sachini Ariyaratne

Determination of amino acids that confer unique functions in the histone variant H2A.Z Maternal obesity and exercise programs cardiovascular health in offspring White matter microstructural changes in the neonatal brain following in utero SSRI antidepressant exposure A bioinformatics pipeline for studying non-coding variants in disease Protein tyrosine phosphatase alpha (PTPa) regulates invadopodiamediated matrix degradation Determining a genetic cause of familial intracranial aneurysms Altered genome-wide DNA methylation in the cord blood of assisted reproductive technology conceived neonates Roles of Bcl-xL in mitochondrial morphology, dynamics, and function in pancreatic ß-cells

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Nicha Boonpattrawong Kayleigh Campbell Madeline Couse Lisa Decotret Emma Hitchcock Kenny Louie Rocky Shi

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Session Three – Masters Students Participant

Abstract Title

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Zhengcheng He

Loss-of-function mutations in breast cancer 1 (BRCA1) predispose women to develop aggressive basal-like breast cancers

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Sohyeong Kang

MALT1-deficient CD4 T cells exhibit decreased IL-2 secretion and impaired Th1 and Th17 differentiation PI3Kp110d drives intestinal fibrosis in SHIP deficient mice Exploring the relationship between cardiovascular disease risk factors and methyl nutrient status in children with mental health conditions Gliomas in adults and children with neurofibromatosis 1 Comparison of the quantity and quality of mononuclear cells isolated by the conventional density gradient centrifugation method versus using SepMate isolation tubes for biobanking purposes

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Young Lo Sarah Montgomery

Laura Sellmer Thyrza May Toledo

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Session Four – Doctoral Students Participant

Abstract Title

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Ana Cohen

Exome sequencing of patients with Weaver-like features links another cancer gene, EED, to overgrowth syndromes

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Bernard Kan Crystal Karakochuk

Defects in innate immune metabolism in infants born prematurely The effect of oral iron with or without multiple micronutrients on hemoglobin concentration among Cambodian women of reproductive age Understanding cost drivers for health technology assessment in maternal, newborn and child health: Lessons from the Community Level Interventions for Pre-eclampsia (CLIP) Trial in low-income countries Unique functions for the Yaf9 YEATS domain Using DNA methylation signatures in placental tissue and cells to gain insight into chorioamnionitis Neonatal and maternal outcomes following attempted operative vaginal delivery at midpelvic station

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Asif Khowaja

Alyssa Kirlin Chaini Konwar Giulia Muraca

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Session Five – Doctoral Students Participant

Abstract Title

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Hani Bagheri

Identifying candidate genes for 2p15p16.1 microdeletion syndrome using clinical, genomic, and functional analysis

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Joshua Brown

Distinct functions of Rtt107 in checkpoint regulation and genome maintenance

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Session Five – Doctoral Students (Continued) Participant

Abstract Title

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Harpreet Chhina

Understanding the health impact of lower limb deformities on pediatric patients: An interpretive description qualitative study Does a 12-week supervised exercise program reduce aortic stiffness in obese children?

Sphingosine-1-phosphate promotes ovarian cancer cell proliferation by disrupting Hippo signaling

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Adaptors recruit the yeast Chorein homolog Vps13 to distinct membranes in the cell Chemokines and their function in neonatal immune responses Tuft cells and their role in intestinal inflammation

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Kathryn Duff Qianlan Fan Kathleen Kolehmainen Elizabeth Marchant Jean Sauvé

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Session Six – Doctoral Students Participant

Abstract Title

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Nick Dawson

High-dimensional analysis of human regulatory T cells using mass cytometry

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Robine Donken

Are the findings of the QUEST study (Quadrivalent HPV Vaccine Evaluation Study) surveys comparable to other young adolescents in BC Human sperm DNA methylation and exposure to childhood abuse The Fc gamma receptor IIA (Fc gamma RIIa) gene variant increases macrophage inflammatory responses and reduces antibodymediated anti-inflammatory macrophage activation Abnormal brain activation during internal speech in schizophrenia: A multi-experiment fMRI analysis The intestinal microbiome in early life asthma Beta cell death promotes an anti-inflammatory and regenerative phenotype in resident islet macrophages Prevalence of incidental findings in a multi-diagnosis psychosis, addiction and infection population in Vancouver’s Downtown Eastside

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Nicole Gladish Lisa Kozicky

Nicole Sanford Leah Stiemsma Dominika Nackiewicz Melissa Woodward

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Session Seven – Doctoral Students Participant

Abstract Title

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Sarah Anderson

Sex differences in the association between callous-unemotional traits and pregnancy

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Stephanie Campbell

Trithorax group complexes are essential for pancreatic endocrine and exocrine cell specification Cell cycle regulated centrosome orientation and centrosome nucleation during directed migration requires Aurora kinase A

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Tony Lok Heng Chu

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Session Seven – Doctoral Students (Continued) Participant

Abstract Title

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Christina Michalski

Assessing the potential for innate immune memory of cord blood monocytes The role of MALT1 in macrophages

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Placental telomere length decline with gestational age differs by sex and TERT, DNMT1, and DNMT3A DNA methylation Elucidating the paradoxical role of the histone variant H2A.Z and its depositor SWR1-C

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Mahdis Monajemi Samantha Wilson Olivia Wong

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Session Eight – Postdoctoral Fellow, Subspecialty Resident or Fellow Participant

Abstract Title

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Liron Borenstein-Levin

The SPO2 histogram classification - A clinical language for SPO2 targeting and measuring oxygenation instability

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Sarah Hutchison Emily Kieran

Explicit and implicit weight stigma in young children How reliable is the “guarantee” in high frequency oscillatory ventilation with volume guarantee?

Neonatal repeated sucrose exposure induces wide spread reduced white matter in mice High prevalence of acute kidney injury in children with type 1 diabetes presenting in diabetic ketoacidosis

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Manon Ranger Rebecca Ronsley Veronica Schiariti

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What do pediatric pain tools really measure?: Content analysis using 76 the International Classification of Functioning, Disability and Health

Session Nine – Postdoctoral Fellow, Subspecialty Resident or Fellow Participant

Abstract Title

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Maria Aristizabal

Determine the molecular underpinnings of the effect early life exposures in developmental outcomes in D. melanogaster

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Anita Coté

Left ventricular mechanics and exercise capacity in clinically stable pediatric heart transplant recipients Early mortality from external causes in Aboriginal mothers The SMART Program: Costs and health outcomes associated with provision of cost-free highly effective contraception at time of abortion RSV prophylaxis for hemodynamically significant congetal heart disease with four palivizumab seasonal doses; Three years of success in British Columbia Pharmacogenomic prediction of anthracycline-induced cardiotoxicity

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Jenny Fairthorne Saied Samiedaluie

Lana Shaiba

Folefac Aminkeng

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Board # 1 Jun Ming Axel Chu, Masters Student Supervisor: Chiten James Lim, Pediatrics

Substrate stiffness directed differentiation of induced pluripotent stem cells to cardiomyocyte subtypes Jun Ming Axel Chu, Eric Zhao, Mu Chiao, Chinten James Lim

Poster Session One

The differentiation of pluripotent stem cells to cardiomyocytes (heart muscle cells) has the capacity to transform the fields of regenerative medicine and tissue engineering. Traditional differentiation protocols of stem cells to cardiomyocytes had primarily focused on recreating the biochemical signaling events associated with cardiogenesis with little emphasis on physical parameters [4, 5].

These protocols have poor control over differentiation outcomes, particularly in directing stem cell Moderator: specification to specialized cardiomyocyte subtypes (i.e. working-type myocytes versus nodal-type Andy De Souza myocytes) [3]. The ability to precisely control stem cell differentiation to specific cardiomyocyte subtypes is critical for eventual clinical application in cell-based therapies (e.g. working-type Participants: myocytes used in infarct repair and nodal-type myocytes used as biological pacemakers) [6]. Thus, with accumulating evidence suggesting that physical parameters, such as substrate stiffness [1, 2], Karen Davies having a considerable effect on cell differentiation andDawson growth, we speculate that by manipulating Cassandra the stiffness of the substrate on which stem cells grow, it will be possible to generate enriched Giulia Del Gobbo working-type myocytes, or conversely, enriched nodal-type myocytes.

MASTERS STUDENTS

Amanda Henderson Avery Lam He Ren Ben Vanderkruk

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Board # 2 Karen Davies, Masters Student Supervisor: Liisa Holsti, Occupational Science & Occupational Therapy

Long-term follow-up of children with idiopathic toe walking Karen Davies, Alec Black, Michael Hunt, Liisa Holsti Introduction: Toe walking may develop with independent walking, but is considered abnormal in healthy children after the age of two to three years. Idiopathic toe walking (ITW) is a diagnosis of exclusion and is characterized by a persistent bilateral toe-toe gait pattern and lack of heel contact with the floor. This may be associated with pain in the legs or feet, frequent tripping or falling, and ankle injuries. In British Columbia, treatment for ITW varies from physiotherapy, casts or braces, Botulinum toxin A (BoNT-A) injections into calf muscles, and/or surgery. There is little evidence regarding the long-term effects of treatment.

Objectives: To determine long-term conservative treatment outcomes of children with ITW using three-dimensional gait analysis and to explore potential activity limitations and participation restrictions.

Methods: Forty adolescents and young adults diagnosed with ITW between 1997 and 2005 underwent physical assessment and repeat gait analysis to determine the presence of any abnormal gait parameters. Mixed model analysis of variance was used to compare the effects of time and treatment (control versus casting +/- BoNT-A injections) on pre- and post-change scores of kinematic and kinetic variables. Levels of activity and participation were assessed using the Pediatric Outcomes Data Collection Instrument (PODCI) for children up to 18 years and the Medical Outcomes Study 36Item Short Form Survey Instrument (SF-36) for young adults over 18 years.

Results: There were improvements in ankle kinematics and kinetics in stance in the cast group with compensatory increase in maximum knee extension in stance and decrease in maximum knee flexion in swing in both control and cast groups over time. Ankle moments remained abnormal in 90% of the participants at follow-up compared to normative data. The PODCI and SF-36 demonstrated 60% and 67% of participant scores, respectively, above the general population mean in global functioning and physical component.

Conclusion: Adolescents and young adults treated conservatively for ITW as children demonstrated persistent alterations in kinematic and kinetic variables. Despite perseverance in gait changes, selfreported questionnaires suggest there is minimal impact on activity and participation.

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Board # 3 Cassandra Dawson, Masters Student Supervisor: Catherine Pallen, Pediatrics

PTPα regulates focal adhesion dynamics and cell polarity to coordinate cell migration Cassandra M E Dawson, Jing Wang, Chinten J Lim, Catherine J Pallen Cell movement is a conserved cellular process that determines embryonic development, wound healing, angiogenesis, and immune cell surveillance and responses. Improperly regulated cell migration is implicated in several pathologies, notably cancer metastasis that involves tumor cells with enhanced and acquired motile properties.

Integrins are cell receptors that regulate migration. Upon binding to the extracellular matrix, integrins are activated and induce signaling events to promote the assembly of multi-protein complexes called focal adhesions (FAs). FAs regulate the reorganization of the actin cytoskeleton to coordinate cell movement. Protein tyrosine phosphatase alpha (PTPα) is a positive regulator of integrin signaling and fibroblast migration. In this ‘normal’ cell setting, integrin engagement initiates PTPα-catalyzed activation of Src to promote formation of the central Src-FAK kinase complex. In turn, PTPα is phosphorylated by Src-FAK at Tyr789. PTPα-phosphoTyr789 (pTyr789) is important for downstream migration signaling. Our goal is to define the roles of PTPα, and in particular PTPαpTyr789, in regulating FA dynamics and cell movement.

I have used several mouse embryo fibroblast (MEF) model systems that express PTPα (wild-type, WT) or unphosphorylatable mutant PTPα-Y789F, or that lack PTPα (knockout, KO), to identify and distinguish the actions of PTPα and PTPα-pTyr789 in (a) FA assembly, turnover and stability and (b) in cell polarity, directionality, and rates of spreading and migration. These events have been visualized at fixed intervals and continuously in real time. So far, my studies have revealed notable differences in integrin-induced FA formation (organization, size, number) between WT and PTPα-KO MEFs. Live cell imaging indicates that cells expressing mutant PTPα-Y789F have more static or stalled FA cycling. In addition, cell polarity and directionality are defective in cells lacking PTPα, in accord with impaired migration ability. Ongoing investigations will provide more insight as to the specific roles of PTPα and PTPα-pTyr789 in the coordination of these processes, providing opportunities to translate our findings into strategies that will disrupt the motility of cancer cells.

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Board # 4 Giulia Del Gobbo, Masters Student Supervisor: Wendy Robinson, Medical Genetics

Placental MTHFR 677C>T genotypes in pregnancy pathologies GF Del Gobbo, EM Price, CW Hanna, WP Robinson One-carbon metabolism is the biochemical pathway that activates and transfers one-carbon units for methylation reactions and nucleotide synthesis. A key step in this pathway is catalyzed by 5,10-methylenetetrahydrofolate reductase (MTHFR), which irreversibly commits one-carbon units to methylation reactions. A non-synonymous SNP in MTHFR, c.677C>T, produces a thermolabile enzyme with reduced function, which can be further exacerbated under folate-limited conditions.

During pregnancy, the placenta extracts and concentrates folate from maternal circulation. Both maternal and fetal MTHFR 677 variants have been associated with pregnancy complications including miscarriage, neural tube defects (NTDs), and pre-eclampsia.

Objectives: To determine whether placental MTHFR 677 variant is associated with NTDs and pregnancy complications of placental insufficiency (PI), and whether the variant genotype affects birth weight/placental weight (BW/PW) ratio.

Methods: 195 control, 55 NTD and 65 PI placentas were genotyped by pyrosequencing at MTHFR 677. Chi-squared tests were used to assess whether there was an increase in T/T genotype frequencies in placentas associated with NTD and PI pregnancies compared to controls. Fisher’s Exact tests were used to investigate T/T genotype frequencies in PI sub-pathologies. ANOVA was used to compare BW/PW ratio between MTHFR 677 C/C + C/T genotype and T/T genotype placentas in a subset of N=173 controls.

Results: Study population genotype frequencies were C/C: 0.498, T/C: 0.422, and T/T: 0.076.

This does not deviate from Hardy-Weinberg equilibrium and follows expectations for a majority Caucasian and Asian population. Compared to controls (T/T: 0.051), NTD T/T frequency (0.091) was not significantly different (p = 0.439). The PI group had a marginally significant increase in T/T genotypes (T/T: 0.138, p=0.039) compared to controls. When the PI cases were divided by their subpathologies of pre-eclampsia (both early- and late-onset) and normotensive IUGR, we found that no individual pathology drove the increased T/T frequency in the PI group. We found no significantly different BW/PW ratios associated with placentas with the MTHFR 677 T/T genotype (p=0.647).

Conclusion: Fetal MTHFR c.677C>T genotype does not contribute significantly to risk of pregnancy complications or altered BW/PW ratio in our folate-supplemented population. However, follow-up studies with larger sample sizes may be warranted for specific PI sub-pathologies.

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Board # 5 Amanda Henderson, Masters Student Supervisor: Angela Devlin, Pediatrics

The role of insulin-like growth factor-1 in programming of offspring adiposity by maternal folate/ vitamin B12 imbalance Amanda M Henderson, Rika E Aleliunas, Nolan G J Chem, Daven C Tai, Tim J Green, Angela M Devlin Developmental programming suggests prenatal and early postnatal environment can impact risk for chronic disease later in life. Population studies have reported greater insulin resistance and adiposity in children from mothers with adequate folate but low vitamin B12 (B12) status during pregnancy.

Folate is metabolically linked to B12. Even with adequate folate, low B12 status can trap folate in an inactive form. Folate deficiency is rare in Canada due to fortification of grains, yet 1 in 20 Canadians is deficient in B12. The Devlin lab previously reported sex-specific programming of adiposity by maternal folate/B12 imbalance in mice. Male offspring from folic acid supplemented mothers had less adipose tissue, whereas female offspring had greater adiposity and glucose intolerance. The mechanisms underlying maternal folate/B12 imbalance and offspring adiposity are not understood.

A recent study reported maternal B12 deficiency disrupts the growth hormone (GH)/insulin-like growth factor-1(IGF-1) axis. The goal of this study is to determine if maternal folate/B12 imbalance affects offspring IGF-1 axis and fatty acid metabolism.

Female mice (C57BL/6J) were fed the following diets 6 weeks prior to conception, through pregnancy, and lactation: control (2mg folic acid/kg diet, M-CON), supplemental folic acid (10mg/kg diet) with B12 (SFA+B12), or SFA without B12 (SFA-B12). One male and one female pup from each dam were weaned onto a control diet or western (45% energy) diet. Offspring tissue was harvested at 20 weeks post-weaning. Serum IGF-1 concentrations were quantified by ELISA. Hepatic mRNA (Igf1, Igfbp2, Cpt1a) and adipocyte mRNA (Scd1) expression was quantified by Real-Time PCR. The effect of maternal diet was determined by 1-way ANOVA. Control diet-fed female SFA-B12 offspring had lower (p<0.05) serum IGF-1 concentrations and higher (p<0.05) hepatic Cpt1a mRNA than M-CON offspring. Western diet-fed female SFA+B12 offspring had higher (p<0.01) hepatic Igf1 mRNA than M-CON offspring. Control diet-fed male SFA-B12 offspring had higher (p<0.05) hepatic Igfbp2 mRNA than M-CON offspring. Western dietfed male SFA-B12 offspring had lower (p<0.05) hepatic Cpt1a mRNA than M-CON and SFA+B12 offspring. No effect of maternal diet on adipocyte Scd1 mRNA was observed.

These findings suggest a role for IGF-1 in programming of offspring adiposity by maternal folate/B12 imbalance.

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Board # 6 Avery Lam, Masters Student Supervisor: Megan Levings, Surgery

Expression and induction of amphiregulin in human regulatory T cells Avery J Lam, Dan Wu, Anne M Pesenacker, Guy Charon, James Pan, John D Rioux, Haiming Huang, Sachdev Sidhu, iGenoMed Consortium, Sabine M Ivison, Megan K Levings Regulatory T cells (Tregs) are essential for maintaining immune homeostasis and self-tolerance.

Multiple lines of evidence suggest that adoptive transfer of immunosuppressive Tregs can prevent, and in some cases cure, a variety of pathological conditions, from autoimmunity to transplant rejection. However, little is known about how they achieve their function in vivo. Several groups have shown that murine Tregs produce the EGF family member amphiregulin (AREG) to promote tissue repair after acute injury or immune insult; murine Treg-derived AREG is induced by the inflammatory cytokine IL-18 or alarmin IL-33. We investigated expression and regulation of AREG in human Tregs.

Human Tregs (CD4+CD25hiCD127lo) stimulated with anti-CD3/28-coated beads showed an early, transient upregulation of AREG mRNA. To determine the ability of IL-18 or IL-33 to further enhance AREG mRNA expression, we investigated IL-18 and IL-33 receptor expression on human Tregs.

We found a subset of memory Tregs that expressed IL-18Ralpha ex vivo, and upon T-cell receptor stimulation, activated Tregs uniformly upregulated IL-18Ralpha expression to a greater extent than activated CD4+ T conventional cells. To measure expression of IL-33Ralpha (ST2), we used phage display to generate a series of single-chain anti-ST2 mAbs. Experiments in transfected 293T cells revealed several candidate anti-ST2 mAbs, which are superior to commercially available flow cytometric antibodies for ST2. Experiments to define subsets of human ST2+ Tregs are in progress.

To determine whether IL-18 or IL-33 regulate AREG in human Tregs, cells will be stimulated via the T-cell receptor with or without IL-18 and/or IL-33; mRNA and secreted AREG protein will be measured over time. Knowledge of whether human Tregs produce AREG is important to understand their potential to mediate tissue repair in addition to immunosuppression when used as a cell-based therapy.

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Board # 7 He Ren, Masters Student Supervisor: Sai Ma, Obstetrics & Gynecology

Altered crossover distribution and distance to telomeres in spermatocytes of infertile men H Ren, K Ferguson, G Kirkpatrick, T Vinning, V Chow, S Ma Objective: Altered frequency and position of meiotic crossovers in infertile men have been linked to spermatogenic arrest, and sperm aneuploidy. Yet, the underlying mechanisms remain unknown.

Recent studies have shed light on the importance of telomere function in the progression of meiosis and fertility. This study aims to investigate the distribution of crossovers and the distance between crossovers and telomeres in spermatocytes of infertile men with obstructive azoospermia (OA), and non-obstructive azoospermia (NOA).

Design: The crossover distributions on chromosomes (chr) 13, 18 and 21 were determined in the spermatocytes of 20 OA, 14 NOA, and 29 control men. The chromosome arms were divided into 10% intervals with respect to the total length. The frequency of crossovers in each interval was calculated. Individual infertile men was compared to pooled controls in addition to whole group comparisons. The mean distance of crossovers from telomeres was determined for the pooled OA and NOA groups.

Materials and Methods: Immunostaining was used to observe the synaptomenal complex and MLH1 foci, which localize to crossover sites. Chr 13, 18 and 21 were identified by fluorescence in situ hybridization. Micromeasure V3.3 was used for MLH1 distribution and distance analysis. The MannWhitney, Ď&#x2021;² and Fisher tests were used for statistical analysis.

Results: Eight out of 20 OA, and 9 out of 14 NOA men showed a significantly altered crossover distribution on at least one of the chromosome arms studied. The NOA group showed significantly altered crossover distribution on chr 21, while both OA and NOA groups displayed altered distribution on chr 18 compared to controls. The OA and NOA men with altered crossover distributions also displayed an increased mean distance between crossovers and telomeres on the corresponding chromosome.

Conclusion: Both OA and NOA men exhibit meiotic defects in the form of altered crossover distribution. These men may also display an increased distance between the crossovers and telomeres, suggesting an inhibition of recombination events near the telomeres, as well as a telomeric role in the increase in recombination errors observed in some infertile men. Future work in this area may elucidate the possible mechanisms involved in male infertility.

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Board # 8 Ben Vanderkruk, Masters Student Supervisor: Brad Hoffman, Surgery

Myt3 protects islet cells from glucotoxic cell death by suppressing Bim Ben Vanderkruk, Bryan R Tennant, Jasmine Dhillon, Derek Dai, Bruce Verchere, and Brad G Hoffman Diabetes arises when pancreatic islets do not produce enough insulin to maintain blood glucose within optimal levels. In Type 1 Diabetes, autoreactive immune cells infiltrate the pancreas and kill the insulin-secreting β-cells of the islets. Stressors in the islet environment, including inflammatory cytokines and metabolic signals, contribute to β-cell dysfunction and death by effecting changes in β-cell gene expression. Islet transplantation is an effective method of diabetes treatment, however, considerable loss of donor cells occurs during the first days following transplantation. To improve graft performance, we need a better understanding of islets’ acute response to post-graft stressors.

Previous work has shown that the transcription factor Myt3 has a pro-survival function in pancreatic islet cells, but is suppressed by exposure to inflammatory cytokines. Here, we examine the function of Myt3 in vivo by suppressing its expression in a syngeneic transplant in mice.

We hypothesized that suppression of Myt3 in this model would increase islet cell apoptosis and therefore reduce the capacity of islet transplants to maintain normoglycaemia.

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Poster Session Two MASTERS STUDENTS Moderator: Elodie Portales-Casamar Participants: Sachini Ariyaratne Nicha Boonpattrawong Kayleigh Campbell Madeline Couse Lisa Decotret Emma Hitchcock Kenny Louie Rocky Shi

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Board # 9 Sachini Ariyaratne, Masters Student Supervisor: Michael Kobor, Medical Genetics

Determination of amino acids that confer unique functions in the histone variant H2A.Z Sachini W Ariyaratne, Michael S Kobor In eukaryotic cells, DNA is packaged by wrapping around an octamer of histones forming the nucleosome. The histone composition of nucleosomes is an important regulatory mechanism because incorporation of histone variants can create regions that are easier or more difficult to unwind and transcribe. One such histone variant is H2A.Z, is highly conserved across eukaryotes.

In yeast, H2A.Z is encoded by the HTZ1 gene; htz1 mutants have slow growth and are far more sensitive to genotoxic agents [1]. H2A.Z is deposited in a replication-independent manner by the ATP-dependent remodelling complex, SWR1-C [5]. Other unique functions of H2A.Z are the formation of heterochromatin boundaries and a role in the DNA damage response [1-2]. The yeast amino acid sequence of H2A.Z is 60% identical to H2A, [3] yet it is not known which regions of H2A.Z account for its unique functions.

By constructing hybrid proteins in which distinct regions of H2A are replaced with corresponding regions of H2A.Z, our lab showed that the M6 region (i.e. the Îą-C helix) confers specific functions to H2A.Z. H2A-M6 was then used to sequentially reconstruct H2A.Z by interchanging the three most divergent regions between H2A.Z and H2A: the N-terminus, the L1 loop, and the L2 loop. This hybrid construct, H2A-NL1L2C, still only partially complemented the htz1 phenotype. H2A.Z and the hybrid construct H2A-NL1L2C differ by only 11 amino acid residues. To determine which of these amino acids are essential, I introduced the H2A.Z-specific residues to the hybrid construct H2A-M6 and looked for the return of H2A.Z function (Figure 2A). I will assess the function of the hybrids using (i) yeast growth assays to test their sensitivity to different growth conditions such as caffeine, hydroxyurea and formamide and (ii) chromatin association assays to study the incorporation of the hybrids into chromatin, (iii) ChIP-qPCR to determine the localization of the hybrids at specific loci in the genome, (iv) RT-qPCR to determine whether the hybrids affect expression of H2A.Z dependent genes, and (v) immunoprecipitation to test the interaction of the hybrids with Chz1, a histone H2A.ZH2B dimer specific histone chaperone [15]. However, if these H2A/H2A.Z hybrids do not confer all the tested H2A.Z specific functions/properties, I will use a combined approach to see if H2A.Z function can be restored. This combination of biochemical and genetic studies will help to elucidate essential amino acids of H2A.Z that are responsible for its unique functions.

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Board # 10 Nicha Boonpattrawong, Masters Student Supervisor: Angela Devlin, Pediatrics

Maternal obesity and exercise programs cardiovascular health in offspring Nicha P Boonpattrawong, Daven C Tai, Rika E Aleliunas, Angela M Devlin Environment during development may influence risk for chronic disease, such as cardiovascular disease (CVD), later in life. Approximately 50% of women of childbearing age are overweight (BMI 25-29.9 kg/m2) or obese (BMIâ&#x2030;Ľ30 kg/m2) in Canada. Several rodent studies have reported that offspring from obese dams have greater adiposity, insulin resistance, and vascular endothelial dysfunction â&#x20AC;&#x201C; an early indicator of CVD. One aspect of vascular endothelial dysfunction is reduced nitric oxide-mediated vasodilatation. The goal of this study is to determine if maternal exercise during pregnancy mitigates the adverse effects of maternal obesity on their offspring.

Female (C57BL/6) mice (n=4-10) were fed from weaning a control (10% kcal fat) or western diet (45% kcal fat) to induce excess adiposity, with or without access to a running wheel. At 16 weeks they were bred and maintained on the diets, with and without exercise, throughout pregnancy and lactation.

Offspring (n=3-10) were weaned onto either the control or western diet and fed for 13 weeks; male offspring were studied. Glucose homeostasis was assessed by intraperitoneal glucose tolerance test (IPGTT). Vascular endothelial function was assessed in aortic rings by isometric force measurement of vasodilatation in response to acetylcholine (endothelial-dependent) and sodium nitroprusside (endothelial-independent) and vasoconstriction in response to phenylephrine.

Sedentary dams fed the western diet (MWS) had higher weight (p<0.001), higher fasting blood glucose and greater glucose intolerance (IPGTT area under the curve) (p<0.05) than control dietfed (MCS) dams. Exercised dams had lower (p=0.071) fasting blood glucose than sedentary dams.

MWS offspring had greater body weight (p<0.001) at weaning than MCS offspring. MCE and MWE offspring weight at weaning and 13 weeks post-weaning were lower (p<0.05) compared to MCS and MWS offspring. MWS offspring had greater glucose intolerance (p<0.01) than MCS offspring.

MWS offspring had greater glucose intolerance (p=0.01) then MWE offspring. Maximum contraction induced by phenylephrine was higher (p<0.05) in MWS offspring than MCS offspring fed the postweaning control diet.

Maternal exercise mitigates the adverse effects of the western diet in dams and male offspring. The findings suggest beneficial effects of exercise in obese dams during pregnancy on CVD risk in the dams and their offspring.

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Board # 11 Kayleigh Campbell, Masters Student Supervisor: Tim Oberlander, Pediatrics

White matter microstructural changes in the neonatal brain following in utero SSRI antidepressant exposure Kayleigh S J Campbell, Lynne J Williams, Daniel H C Kim, Ursula Brain, Bruce H Bjornson, Ruth E Grunau, Dan W Rurak, Steven P Miller, Tim F Oberlander Background: Maternal use of selective serotonin reuptake inhibitor (SSRI) antidepressant medications during pregnancy has been associated with neonatal neurobehavioural disturbances, raising critical questions regarding their effect on early brain development. Given the role of serotonin in early neuron growth, differentiation, and maturation in the brain, altered serotonin signaling may influence the developing central nervous system; however, how SSRIs shape early brain development remains to be determined. In this study, we examined in vivo white matter (WM) microstructure and connectivity in term-born neonates following in utero SSRI exposure.

Methods: Term-born SSRI-exposed and non-exposed (control) 6-day-old neonates (mean GA = 40.09 weeks, n=48 to date) were studied with magnetic resonance diffusion tensor imaging (7000s TR, min TE, 20.0 FOV, 100x100 matrix, 2mm slice thickness, 32 directions, B=700(1000) s/mm2).

Diffusion tensor imaging (DTI) yields measures of fractional anisotropy (FA), and mean, axial, and radial diffusivities (MD, AD, RD), which reflect WM microstructural development and connectivity.

Exploratory tract-based special statistics (TBSS) was used to examine whole-brain WM tracts to identify specific fibers that differ in FA by SSRI exposure.

Results: TBSS indicated that SSRI-exposed neonates may have higher FA in WM fibers of the cingulum and caudal fibers of the corticospinal tract, adjusting for maternal mood and neonatal age in statistical analyses (p = 0.08, n=30). An a priori region-of-interest (ROI) approach will also be undertaken to further characterize specific WM tracts in the territories of the high centrum semiovale, basal ganglia, and midbrain.

Conclusions: These findings provide initial evidence that specific WM fibers may be affected by in utero SSRI drug exposure, even when adjusting for maternal mood. MRI analysis continues, as additional subjects are studied in this ongoing research. The behavioural correlates of our findings will also be studied.

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Board # 12 Madeline Couse, Masters Student Supervisor: Jan Friedman, Medical Genetics

A bioinformatics pipeline for studying non-coding variants in disease Madeline Couse, Farah Zahir, Gabriella Horvath, Clara van Karnebeek, Maja Tarailo-Graovac, Casper Shyr, Jan Friedman Hereditary and sensory autonomic neuropathies (HSAN) are are group of clinically and genetically heterogeneous disorders of the peripheral nervous system. We are working with eight patients affected by HSAN, whose symptoms include loss of pain sensation, developmental delay, and gastrointestinal complications. We have performed whole genome sequencing on these patients and analyzed coding variants, but have only reached a diagnosis in two cases. I hypothesize that the pathogenic variants in these patients lie in regulatory regions of genes associated with HSAN. In this study, I investigate rare variation in regulatory elements of the genome: promoters, enhancers, untranslated regions, regions sensitive to purifying selection, and topological associated domains.

I implement a custom bioinformatics pipeline that filters rare regulatory single nucleotide variants, indels, and structural variants from patient whole genome vcf and bam files. I discriminate a single heterozygous SNV in one patient at a conserved locus in the 3â&#x20AC;&#x2122;UTR of PMP22 that is predicted by CADD and FATHMM-MKL scores to be deleterious. Genotype-phenotype correlation, however, does not correlate the patient phenotype with this particular gene. On the other hand, the gene is dosage-sensitive and can cause a broad range of phenotypes. I will therefore perform further validations studies on this variant. The pipeline developed for this study is easily modified to analyzing other genetic diseases, and will be valuable for discriminating non-coding, pathogenic variants in future studies.

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Board # 13 Lisa Decotret, Masters Student Supervisor: Catherine Pallen, Pediatrics

Protein tyrosine phosphatase alpha (PTPα) regulates invadopodia-mediated matrix degradation Lisa Decotret, Catherine J Pallen Introduction: Normal cell migration is a highly conserved process that plays a critical role in many physiological processes including wound healing and immune cell response. Aberrant cell migration is implicated in cancer metastasis, which is the leading cause of cancer related mortalities. In normal cells, cell migration is a dynamic process in which the cell adheres to and then releases from the extracellular matrix (ECM), which involves specialized structures called focal adhesions (FAs). In highly invasive tumour cells, invasive ability is mediated by similar integrin-mediated structures called invadopodia. These are Src-regulated dynamic actin-based protrusions of the plasma membrane that mediate extracellular matrix (ECM) degradation. Protein tyrosine phosphatase alpha (PTPα), a widely expressed transmembrane protein, positively regulates integrin signaling and promotes cell migration. Recent findings have demonstrated that PTPα is a critical Src activator and that subsequent Src-mediated phosphorylation of PTPα at Tyr789 is required for normal cell migration.

However, little is known about the role of PTPα in cancer cell motility. Our goal is to determine the roles of PTPα in Src-signaling mechanisms that regulate invadopodia structure and function to promote the invasive motility of malignant cells.

Methods: We are currently investigating the structural and functional consequences of the loss of PTPα on invadopodia-mediated cancer metastasis. I first used siRNA to knockdown PTPα in the invasive MDA-MB-231 breast cancer cell line. Then, I performed an invadopodia-mediated ECMdegradation assay using Oregon Green-488 conjugated gelatin coated coverslips to determine the ECM-degradation ability of wild-type vs. PTPα-depleted MDA-MB-231 cells. Finally, I confirmed that ECM-degradation occurs where invadopodia form (marked by co-localized actin/cortactin) using immunofluorescence microscopy.

Results: Small interfering-RNA mediated depletion of PTPα reveals an impaired ability of invadopodia to degrade ECM, indicating the importance of PTPα in invadopodia function. However, through the use of immunofluorescence microscopy, it appears that PTPα may not regulate the formation of invadopodia.

Conclusion: Our preliminary data suggest that PTPα positively regulates the ECM-degradation ability of invadopodia. Thus, PTPα may play a role in invadopodia-mediated cancer invasive motility, which may lead to new mechanistic targets for therapeutic interventions to prevent cancer metastasis and limit mortality.

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Board # 14 Emma Hitchcock, Masters Student Supervisor: William Gibson, Medical Genetics

Determining a genetic cause of familial intracranial aneurysms Emma Hitchcock, Jillian Diamond, Patrice Eydoux, Gary Redekop, Katelin Townsend, William T Gibson Introduction: Intracranial berry aneurysms (IBA) are a common disease that occur in 1-3% of the general population, and in 3.6-6.5% of adults over 30 years of age. Approximately 12-15% of patients have affected first-degree relatives, and are considered to have familial intracranial aneurysms (FIA). No specific genetic variants causing isolated IBA or FIA have been identified thus far. The aim of this study is to identify rare DNA variants that are major risk factors for FIA. Methods and Results: This study currently has enrolled three families with FIA, and recruitment of additional families is ongoing. We analyzed family one using whole-genome SNP microarrays to map genomic regions shared only among affected family members, in combination with wholeexome sequencing (WES) to identify rare genetic variants in a single proband. Overlap of these data produced a list of 112 candidate variants. Whole-genome sequencing will be performed on the proband of family two. WES will be performed on family three and on the probands of newlyenrolled families. We describe a detailed workflow of the analysis of sequencing data obtained from these families. Candidate variants were selected for being rare and potentially damaging, then subsequently prioritized by the geneâ&#x20AC;&#x2122;s involvement in an associated syndrome, vascular function, or inflammation. Genes containing candidate variants in multiple independent families will be modeled in zebrafish.

Discussion: A validated FIA gene would be expected to identify a key protein in the molecular pathogenesis of intracranial aneurysms in both its familial and sporadic forms.

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Board # 15 Kenny Louie, Masters Student Supervisor: Sai Ma, Obstetrics & Gynecology

Altered genome-wide DNA methylation in the cord blood of assisted reproductive technology conceived neonates Kenny Louie, Edgar Chan Wong, Sai Ma Objective: The objective of this study is to determine whether there is altered genome-wide DNA methylation in the cord blood of assisted reproductive technology (ART) derived neonates compared to spontaneous conceptions (SC). Furthermore, we aimed to determine whether in vitro culturing plays a role in altered DNA methylation by also comparing ART neonates to intrauterine insemination (IUI) neonates.

Design: We studied the DNA methylation at 1505 CpG sites in the cord blood of 17 in vitro fertilization (IVF), 15 intracytoplasmic sperm injection (ICSI), 16 IUI, and 16 SC singletons from multiple hospitals in Vancouver.

Materials and Methods: Cord blood was extracted at the time of birth and DNA was extracted using the Puregene Gentra Blood Kit (Qiagen). DNA was bisulfite converted with the EZ DNA methylation Gold Kit (Zymo) and was then applied to the Illumina GoldenGate Methylation Cancer Panel I at the Centre for Applied Genomics (The hospital for Sick Kids, Toronto). Raw data was imported into Illuminaâ&#x20AC;&#x2122;s BeadStudio 3.1.3.0 and differential methylation analysis was conducted with background correction and probe exclusion (detection P-value > 0.05). Mann-Whitney with FDR correction was used to determine significant CpG sites, where only sites with a diff score Âą 13 (P-value < 0.05) and absolute mean methylation difference of 10% were considered significant. This study was approved the University of British Columbia Ethics.

Results: The exon of EPHB1 was altered in DNA methylation in IVF neonates compared to all other groups. The CFTR and RARRES1 promoters were also altered in IVF neonates compared to SC and IUI. The exon of IGSF4C was exclusively altered in IVF neonates compared to IUI. The EFNB3 exon was altered in ICSI neonates compared to SC. The IUI neonates were not found to be significantly different to SC at any CpG site.

Conclusions: We identified altered DNA methylation in the cord blood of ART neonates suggesting a potential risk in the use of ART on the health of the newborn. Furthermore, we identified altered DNA methylation that may be explained by differences between IVF and IUI techniques such as the use of culture medium.

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Board # 16 Rocky Shi, Masters Student Supervisor: Dan Luciani, Surgery

Roles of Bcl-xL in mitochondrial morphology, dynamics, and function in pancreatic β-cells Rocky Shi, Ahsen Chaudhry, Dan S Luciani High levels of saturated fatty acids cause insulin-secreting pancreatic β-cells to fail and die, and this is a significant factor in the development of obesity-associated type 2 diabetes (T2D). Mitochondria are essential for β-cell function and it is known that mitochondrial dysfunction contributes to T2D pathogenesis. The regulation of mitochondrial biomass, motility and fission/fusion dynamics are integral to β-cell physiology. Studies have suggested these mechanisms affect the ability of β-cells to withstand nutrient stress, as well as the elimination of damaged mitochondria via mitophagy.

Under chronic stress, the apoptotic death of β-cells is regulated by Bcl-2 family proteins, including anti-apoptotic Bcl-xL. We recently found that Bcl-xL also dampens mitochondrial metabolism and insulin secretion in healthy β-cells. Additional preliminary data and works in neurons, suggest the non-apoptotic functions of Bcl-xL extend to regulation of β-cell mitochondrial biogenesis and dynamics. Following the overexpression of eYFP-tagged Bcl-xL in β-cells, we observe a striking mitochondrial morphological change, as mitochondria aggregate and lose their normal tubular network structure. In agreement with an inhibitory role of Bcl-xL on oxidative phosphorylation, this is associated with decreased O2 consumption. We hypothesize that these morphological and metabolic changes are due, in part, to a dysregulation of the fusion-fission processes involved with mitochondrial networking and quality control. To test this hypothesis, I will use qPCR and Western Blot to determine the effect of Bcl-xL knockout and overexpression on mitochondrial mass, as well as the expression of proteins involved with mitochondrial biogenesis and networking.

I will characterize mitochondrial morphology using confocal microscopy, and I use mitochondriatargeted photoactivatable GFP (mtPA-GFP) to track the movement of specific mitochondria within their dynamic network. To determine the importance of Bcl-xL and mitochondrial dynamics for the adaptation of β-cells under pro-diabetic conditions, I will investigate these morphological and functional changes in response to the lipotoxic stress associated with culture in high concentrations of palmitate. Clarifying the involvement of Bcl-xL in mitochondrial morphology and function will enhance our understanding of β-cell physiology and may provide new insight to the pathophysiology of diabetes.

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Poster Session Three MASTERS STUDENTS Moderator: Matthias Gรถrges Participants: Zhengcheng He Sohyeong Kang Young Lo Sarah Montgomery Laura Sellmer Thyrza May Toledo

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Board # 17 Zhengcheng He, Masters Student Supervisor: Christopher Maxwell, Pediatrics

Loss-of-function mutations in breast cancer 1 (BRCA1) predispose women to develop aggressive basal-like breast cancers Z He, O Nemirovsky, N Kannan, CJ Eaves, CA Maxwell Oriented progenitor cell divisions are crucial to maintain tissue homeostasis. The human mammary gland is dynamic and, in response to hormones, must expand in a manner that maintains the correct content of epithelial cell subsets, including luminal, basal, stem and progenitor cells. Breast cancers that arise in carriers of BRCA1 mutations phenotypically resemble progenitor cells suggesting that BRCA1 restricts the expansion or controls the turnover of these primitive cells.

Immortalized, non-tumorigenic mammary cells were transduced with lentivirus that encoded shRNA targeting BRCA1, or non-hairpin control, and immediately imaged as cells progressed through division. Silencing BRCA1 resulted in misoriented cell divisions that generated progeny with micronuclei and tetraploidy. Silencing BRCA1 inhibited the clonogenic potential of cells and increased the proportion of basal-like colonies in 2D cultures (on plastic) and non-polarized, proliferative structures in 3D cultures (in matrigel). Clonal BRCA1-silenced mitotic cells had few neighbors, underwent large nuclear displacement during division, and expressed high levels of integrin Îą6 suggesting altered cell-cell contacts or cell-matrix adhesion. We controlled these variables by imaging individual cells seeded on L-shaped laminin- or fibronectin-coated micropatterns, which provided uniform adhesive cues and a defined division axis; however, BRCA1-silenced cells did not correctly orient division under these conditions. Importantly, spindle orientation, genome stability, and clonogenic potential were all impaired when BRCA1 was silenced in luminal progenitor- or basal cell-enriched populations freshly isolated from normal human reduction mammoplasty tissue.

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Board # 18 Sohyeong Kang, Masters Student Supervisor: John Priatel, Pathology & Laboratory Medicine

MALT1-deficient CD4 T cells exhibit decreased IL-2 secretion and impaired Th1 and Th17 differentiation Sohyeong Kang, Yu-Husan Huang, Kevin Tsai, Xiaoxia Wang, Shan-Yu Fung, Stuart Turvey, John J Priatel A child admitted to British Columbia Children’s Hospital displayed a novel clinical presentation of immune dysregulation, exhibiting lymphocytic infiltration and severe inflammation of the intestinal tract and other mucosal surfaces. Whole-exome sequencing revealed that the patient inherited missense MALT1 mutations and her lymphocytes exhibited deficits in MALT1 protein and MALT1dependent signal transduction. MALT1 plays critical roles in T cell receptor signal transduction through at least two different mechanisms: (1) as a signaling adaptor molecule bringing together CARMA-1 and BCL-10 to form the CBM signalosome complex and (2) as a caspase- like protease (paracaspase) cleaving substrates after arginine residues. Studies on Malt1-/- mice have revealed diminished NF-KB activation and weakened T cell immunity whereas mice lacking paracaspase activity but not MALT1 adaptor function are prone to lethal autoimmunity. Altogether, these mouse findings raise questions regarding the nature of our patient’s mutant MALT1 protein and the role it plays in her proinflammatory phenotype. Consequently, we plan to analyze our patient’s MALT1 mutation by investigating the paracaspase activity, signaling, and function of her T cells. Early studies have found that patient CD4 T cells exhibit defects in Th1 and Th17 differentiation and these impairments could be responsible for inefficient immune responses leading to chronic infections.

Finally, a better understanding of MALT1 will provide insight into inflammatory disease and prove invaluable in supporting MALT1-targeted therapies to modulate T cells to treat autoimmune diseases.

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Board # 19 Young Lo, Masters Student Supervisor: Laura Sly, Pediatrics

PI3Kp110δ drives intestinal fibrosis in SHIP deficient mice Young Lo, Jean Philippe Suavé, Susan C Menzies, Laura M Sly Crohn’s disease (CD) is an immune-mediated disease characterized by inflammation along the gastrointestinal tract. One in 3 people with CD will develop intestinal fibrosis requiring surgery within 10 years of diagnosis. Despite that, there are no treatments that target intestinal fibrosis directly.

Our laboratory reported that mice deficient in the Src homology 2 domain-containing inositol polyphosphate 5’-phosphatase (SHIP-/-) develop spontaneous CD-like intestinal inflammation with arginase-dependent fibrosis. We also reported that increased arginase I activity in SHIP-/macrophages was dependent on increased Class IA phosphatidylinositol 3-kinase (PI3K) p110δ activity.

Based on this, we hypothesize that SHIP-/- mice develop fibrosis due to increased PI3Kp110δ activity.

SHIP-/- mice were crossed with mice deficient in PI3Kp110δ activity (PI3Kp110δDA/DA).

PI3Kp110δDA/DA SHIP-/- mice have reduced intestinal fibrosis compared to their SHIP-/- littermates including: reduced muscle thickening, vimentin+ mesenchymal cells, collagen deposition, arginase activity, TGFβ, IL-4, and IL-13. PI3Kp110δ deficiency also reduced immune cell infiltration and IL-1β in the SHIP-/- ileum suggesting that PI3Kp110δ and/or fibrosis may contribute directly to inflammation. SHIP-/- mice were also treated with a PI3Kp110δ isoform-specific inhibitor, IC87114.

Pharmacological inhibition of PI3Kp110δ activity also reduced the above parameters that are associated with intestinal fibrosis in SHIP-/- mice.

Our data suggest that SHIP deficient mice develop intestinal fibrosis due to increased PI3Kp110δ activity. Moreover, targeting PI3Kp110δ activity may be an effective strategy to reduce intestinal fibrosis in people with CD. Importantly, idelalisib, a PI3Kp110δ isoform-specific inhibitor, is already licensed for use in people with certain leukemias and lymphomas, so may be rapidly translatable into an effective therapy for intestinal fibrosis in people with CD.

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Board # 21 Sarah Montgomery, Masters Student Supervisor: Angela Devlin, Pediatrics

Exploring the relationship between cardiovascular disease risk factors and methyl nutrient status in children with mental health conditions Sarah Montgomery, Teodoro Bottiglieri, Yvonne Lamers, Constadina Panagiotopoulos, Angela Devlin In BC it is estimated that approximately 14% of children experience a mental health condition (MHC); many of them are treated with second-generation antipsychotics (SGAs). We were the first to report metabolic side effects, such as obesity, elevated blood pressure, fasting blood glucose, and dyslipidemia in SGA-treated children compared to SGA-naïve children. We further identified a relationship between variants in genes encoding enzymes involved in methyl nutrient metabolism with metabolic side effects in SGA-treated children, but not SGA-naive children. The goal of this study is to characterize the methyl nutrient status of SGA-treated and SGA-naïve children. A crosssectional population of SGA-treated and SGA-naïve children (n=45) was recruited from Child and Adolescent Psychiatry at BC Children’s Hospital. Anthropometric measures (weight, height, body fat percent and waist circumference), blood biomarkers of metabolic health (fasting glucose, HDL, LDL, total cholesterol, and triglycerides), systolic and diastolic blood pressure, methyl nutrient metabolites (folate, methionine, cystathionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), total homocysteine (tHcy), and vitamin B12), were analyzed. Elevated serum folate (>45.38μM/L) was observed in 42.6% of the children; 35.2% had normal serum folate (13.5-45.38μM/L) and 5.6% were marginally deficient (6.8-13.48μM/L). The majority (82.9%) of participants had adequate serum B12 (>220 pmol/L), but 2.9% were deficient (<148pmol/L). The median serum cystathionine concentration of our sample was 87.8 nM/L (25th, 75th percentiles: 55.95, 138.50), and the median serum total Hcy concentration was 5.70 μM/L (25th, 75th percentiles: 3.20, 14.40). We found no differences in methyl nutrient status between SGA-treated children and SGA-naïve children.

However, we observed positive relationships between serum SAM and SAH concentrations, and zBMI (p=0.018 and p=0.009, respectively). SAM, SAH, and tHcy concentrations differ across age ranges and by sex; therefore, we plan to control for these variables as our sample size increases. The relationship between SAM and zBMI, and SAH and zBMI is not clear at this time; further research is warranted to reveal the mechanisms underlying these associations.

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Board # 22 Laura Sellmer, Masters Student Supervisor: Jan Friedman, Medical Genetics

Gliomas in adults and children with neurofibromatosis 1 Laura Sellmer, Marco Marangoni, Manraj Heran, Patricia Birch, Said Farschtschi, Victor-Felix Mautner, Jan M Friedman Background: Non-optic gliomas are one of the most common tumours in patients with NF1. The natural history and frequency of these tumours are incompletely understood.

Methods: 1722 whole-body MRI scans were obtained from 562 unselected individuals with NF1 at the NF outpatient department of the University Hospital Hamburg-Eppendorf between 2003 and 2015. We analyzed the clinical features of non-optic gliomas and focused on the differences between affected adults and children.

Results: The number of scans per patient ranged from 1 to 12; patients were followed for a median of 3.7 years. We identified 23 patients (4.1%) with non-optic gliomas. Median age of these patients at first scan was 22.4 years, much higher than previously reported in the literature. 10 tumours were located in the cerebellum, 8 in the brain stem, 4 in the corpus callosum, 3 in the temporal lobe, 1 in the frontal lobe, 1 in the thalamus and 1 in the internal capsule. Histology showed 8 pilocytic astrocytomas and 1 dysembryoplastic neuroepithelial tumour. Only 7 of the 23 glioma patients were symptomatic. 3 individuals developed a tumour after having at least 1 tumour-free scan. The risk of new tumour development was 0.14% (95% confidence interval 0.04% to 0.45%) per patient year of follow-up in patients older than 10 years. No new tumours were diagnosed in children younger than 10 years. 4 cases showed progression and 3 individuals presented with multiple non-optic gliomas.

Non-optic tumours only progressed in the first 4.9 years and only in patients younger than 22.3 years. The rate of progressing non-optic gliomas per patient year of follow-up in the first 5 years after tumour diagnosis was 4.9% (95% confidence interval 1.6% to 13%).

Conclusion: Non-optic gliomas are twice as common in an unselected cohort of NF1 patients as previously reported. This is most likely due to increased frequency of diagnosis of asymptomatic tumours when performing routine head MRIs as well as a higher prevalence in older individuals, who are poorly represented in previous studies.

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Board # 23 Thyrza May Toledo, Masters Student Supervisor: Suzanne Vercauteren, Pediatrics

Comparison of the quantity and quality of mononuclear cells isolated by the conventional density gradient centrifugation method versus using SepMate isolation tubes for biobanking purposes Thyrza May Toledo, Ashish Marwaha, Adam Velenosi, Katelin N Townsend, Nidhi Arora, John Bhullar, Tamsin Tarling, Suzanne Vercauteren Background: Providing high quality biospecimens to researchers while saving cost is important in Biobanking practices. Isolation of mononuclear cells is an expensive and time consuming practice.

The objective of this study was to compare the quantity and quality of mononuclear cells isolated using the traditional density gradient centrifugation method versus a recently developed method using SepMate isolation tubes from STEMCELL Technologies.

Methods: We isolated mononuclear cells from blood using the traditional density gradient centrifugation method or SepMate isolation tubes. The mononuclear cell yields were determined manually using a hemocytometer using a Crystal Violet dye and an automated cell counter. Cells were frozen and stored at -80°C. Cells were then thawed and the cell yield, recovery, purity and viability were evaluated. Flow cytometric analysis was performed to determine mononuclear composition and viability.

Results: There was no significant difference in the mean mononuclear cell yield obtained with the Ficoll and SepMate method (n=13, p=0.7369). After freeze-thaw, the mononuclear cell recovery and purity between the Ficoll and SepMate method were not significantly different (recovery, n=11, p=0.1651; purity, n=8, p=0.5789). Flow cytometry showed that the two methods were comparable in terms of total lymphocyte yield (Ficoll: 44.6±14.3% vs SepMate: 43.6±13.6%), total CD3+ T-cell yield (Ficoll: 29.0±15.5% vs SepMate: 30.3±14.3%), and within the CD3+ population, CD4+ T-cell yield (Ficoll: 46.1±18.3% vs SepMate: 45.1±19.2%) and CD8+ T-cell yield (Ficoll: 43.4±17.8% vs SepMate: 44.2±18.7%). Also, the lymphocyte viability from the Ficoll method of (90.9±1.7%) was comparable with the SepMate method of (91.2±1.4%). Lastly, we found that using the SepMate tubes was more time efficient and cost effective for isolating mononuclear cells from blood.

Conclusions: We conclude that using SepMate tubes can be a time and cost effective method for the isolation of mononuclear cells for Biobanking purposes.

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Poster Session Four DOCTORAL STUDENTS Moderator: John Priatel Participants: Ana Cohen Bernard Kan Crystal Karakochuk Asif Khowaja Alyssa Kirlin Chaini Konwar Giulia Muraca

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Board # 24 Ana Cohen, Doctoral Student Supervisor: William Gibson, Medical Genetics

Exome sequencing of patients with Weaver-like features links another cancer gene, EED, to overgrowth syndromes Ana SA Cohen, Beyhan Tuysuz, Yaoqing Shen, Sanjiv K Bhalla, Steven JM Jones, William T Gibson Our lab discovered that constitutional mutations in EZH2 cause Weaver syndrome, a disorder characterized by overgrowth of the body and head, intellectual disability and cancer susceptibility.

The same gene had been associated to many cancers in the general population, suggesting its important role in cancer initiation and progression. To date we have found pathogenic EZH2 mutations in 9 of 63 patients with Weaver-like features, of which 2 had developed malignancies.

Our current efforts focus on identifying characteristics that will help predict the likelihood of these patients developing cancer, through phenotype/genotype correlations and functional studies.

Given that EZH2 is a histone-modifying enzyme, we further hypothesized that mutations in other epigenetic regulators associated to cancer could explain the overgrowth features seen in our undiagnosed patients. Using whole-exome-sequencing, we identified a de novo mutation in EED in one patient. EED is the main partner of EZH2 within the Polycomb Repressive Complex 2, which maintains gene silencing. Although somatic mutations in EED had been reported in cancers, ours was the first report of a constitutional mutation in the human gene, and its first association with overgrowth syndromes. Subsequently, we have identified a second patient with a different de novo mutation in EED and significant phenotypic overlap to our first case. As such, we are confident that we have identified a novel overgrowth gene. These findings strengthen the hypothesis that de novo constitutional mutations in genes that are mutated somatically in cancer are an important cause of pediatric overgrowth syndromes. Further investigations are needed to make a definitive link between mutations in these genes, Weaver-like syndromes, and cancer development.

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Board # 25 Bernard Kan, Doctoral Student Supervisor: Pascal Lavoie, Pediatrics

Defects in innate immune metabolism in infants born prematurely Bernard Kan, Christina Michalski, Colin Ross, Pascal M Lavoie Background: Activation of the innate immune system involves major changes in cellular energy metabolism. At rest, immune cells largely rely on oxidative phosphorylation, utilizing oxygen for the efficient generation of energy. Upon activation by a foreign antigen or pathogen, cells switch to anaerobic glycolysis for rapid energy production; these metabolic changes are followed by activation of inflammatory immune pathways. In contrast, upon induction of tolerance, cells switch to betaoxidation of fatty acids resulting in increase production of anti-inflammatory cytokines (IL-10, TGF-β), as well as pro-resolving lipid mediators.

Metabolic control over the pro- or anti-inflammatory nature of an immune response is a general requirement amongst immune cells, and is regulated by signalling via the master regulators mTOR and HIF-1Îą. We have previously reported that cord blood cells from infants born before the term of gestation are unable to produce a strong inflammatory response upon innate immune cell activation.

We hypothesize that monocytes from the latter are unable to make the switch to a glycolytic metabolic phenotype.

Objective: To determine the transcriptomic and metabolic profile of neonatal monocytes upon innate immune stimulus, comparing to adult monocytes.

Results: Mononuclear cells from preterm infants have an altered gene expression profile upon stimulation with LPS, as shown by microarray. Specifically, at rest and upon LPS stimulation, the gene expression profile of preterm infants shows a decrease in oxidative phosphorylation pathways compared to term infants and adults. Additionally, preterm infants show a diminished mTOR gene expression profile, suggesting a diminished ability to switch metabolic phenotypes.

Conclusions: Our data demonstrate that at the gene expression level, monocytes from preterm infants have a diminished ability to switch metabolic pathways upon encountering innate immune stimulus. This inability to switch metabolic pathways may underlie the diminished innate immune responses in infants born prematurely.

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Board # 26 Crystal Karakochuk, Doctoral Student Supervisor: Tim Green, Food, Nutrition & Health

The effect of oral iron with or without multiple micronutrients on hemoglobin concentration among Cambodian women of reproductive age Crystal D Karakochuk, Mikaela K Barker, Susan I Barr, Suzanne M Vercauteren, Angela M Devlin, Sophonneary Prak, Kroeun Hou, Tim J Green Background: Recent reports have shown a low prevalence of iron deficiency (ID) among Cambodian women. If true, iron supplementation will not reduce anemia, and at worst, it could cause harm. We measured the effect of iron (Fe) with or without multiple micronutrients (MMN) on hemoglobin (Hb) concentration in Cambodian women.

Methods: In this 2x2 factorial double-blind randomized trial, non-pregnant women (18-45 y) with Hb ≤117 g/L (HemoCue®) were convenience sampled from 26 villages in Kampong Chhnang province and randomized 1:1 to receive 12 wk of daily oral Fe (60 mg), MMN (14 other micronutrients), Fe+MMN, or placebo capsules. Generalized linear models were used to assess the primary outcome: Hb at 12 wk adjusted for baseline values and village clusters (intention to treat).

Results: In July and August 2015, 809 women were recruited and 759 completed the trial. Overall, baseline anemia (Hb <120 g/L) prevalence was 58% using a hematology analyzer. Adjusted mean Hb at 12 wk did not differ in the Fe and Fe+MMN groups (121 vs 123 g/L); and both were higher than MMN and placebo (both 116 g/L; p<0·05). Post-estimation linear comparisons showed that the addition of MMN to Fe did not significantly increase Hb at 12 wk (p=0·56). ‘At the margins’ analysis showed mean (95% CI) Hb was 5·6 (3·8, 7·4) g/L (p<0.001) among women who received Fe (n=383) and 1·1 (-0·7, 2·9) g/L (p=0·24) among women who received MMN (n=382), with no interaction between interventions (p=0·61). At 12 wk, 19% and 30% of women had a Hb response ≥10 g/L in Fe and Fe+MMN groups, compared to 8% and 5% in MMN and placebo, respectively.

Interpretation: Daily Fe supplementation for 12 wk increased Hb concentrations in Cambodian women; however, inclusion of MMN did not confer additional significant benefit. Only ~1/4 of our predominantly anemic study population responded to iron supplementation, which has policy implications for effective anemia reduction. More work is needed to assess the potential risk of blanket iron supplementation among predominantly iron-replete populations with high prevalence of inflammation, infection, and genetic Hb disorders.

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Board # 28 Asif Khowaja, Doctoral Student Supervisor: Peter von Dadelszen, Obstetrics & Gynecology

Understanding cost drivers for health technology assessment in maternal, newborn and child health: Lessons from the Community Level Interventions for Pre-eclampsia (CLIP) Trial in low-income countries Asif Raza Khowaja, Craig Mitton, Rahat Qureshi, Stirling Bryan, Laura Magee, Peter von Dadelszen, Zulfiqar Bhutta Background: Globally, health technology assessment (HTA) in disease prevention and health promotion for maternal, neonatal, and child health (MNCH) has become a top research priority.

Understanding cost-drivers and estimating societal costs are important challenges for HTA in lowand middle-income countries (LMICs). This study assessed cost-drivers to inform the design of an economic model for the Community-Level Interventions for Pre-eclampsia (CLIP) Trial in Pakistan.

Methods: As part of a larger HTA, qualitative research was conducted alongside the CLIP Trial in rural districts of Matiari and Hyderabad, Sindh, Pakistan. Nine focus groups were conducted with a wide range of stakeholders, including pregnant women, mothers-in-law, husbands, fathers-in-law, health care providers at community- and health facility-levels, and district-level health decision-/policymakers. The community perspective included out-of-pocket (OOP), health system, and program costs. Thematic analysis was performed using NVivo software.

Results: Most pregnant women and male decision-makers reported a large burden of OOP costs for in- and out-patient care, informal care from traditional healers, self-medication, childbirth, newborn care, transport to health facility, and, in particular, missed wages by caretakers. Many health care providers identified health system costs associated with human resources for hypertension risk assessment at the household level, transport, and communication about patient referrals. Health decision-makers recognized program implementation costs, such as the mobile health infrastructure, staff training, and monitoring/supervision as major investments for health system.

Conclusions: A thorough understanding of cost drivers is critical in designing an economic model for HTA and understanding the policy implications related to program scale-up should trial results prove favourable.

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Board # 29 Alyssa Kirlin, Doctoral Student Supervisor: Michael Kobor, Medical Genetics

Unique functions for the Yaf9 YEATS domain Alyssa C Kirlin, Michael S Kobor Chromatin must be modified to alter access to the underlying DNA sequence and allow for gene regulation. There are many protein complexes that mediate this process using different mechanisms, such as histone post-translational modification, histone variant incorporation, and ATP-dependent nucleosome remodeling. The YEATS domain is a recurrent protein module in these complexes and likely plays a role in complex localization by interacting with acetylated lysines in histone tails.

Saccharomyces cerevisiae has three YEATS family members: Yaf9, Taf14 and Sas5. At least nine protein complexes contain one of these proteins, suggesting roles for a YEATS domain in histone acetylation, H2A.Z incorporation, chromatin remodeling and transcription. In order to identify shared and unique functions in these family members, we constructed a set of hybrid proteins in which the YEATS domains were swapped in all combinations and tested them for their ability to function in place of the wild type proteins. The hybrid YEATS proteins complemented the impaired growth and drug sensitivity phenotypes of taf14Δ strains. This complementation was not reciprocal, as the growth phenotypes of yaf9Δ were not rescued by the hybrid constructs. Further analysis of the Yaf9derived proteins showed that while they immunoprecipitated with subunits of SWR1-C, they did not with NuA4, despite the presence of the putative coiled-coil domain thought to mediate Yaf9’s incorporation. The construction of Yaf9-like proteins from the Taf14 backbone was able to restore some but not all of Yaf9’s function. Work is now being done to identify the region of the Yaf9 YEATS domain responsible for NuA4 integration and to combine mutations towards a minimally functional domain. This work will contribute to our understanding of how chromatin-modifying complexes are assembled and of the role of the YEATS domain in these complexes.

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Board # 30 Chaini Konwar, Doctoral Student Supervisor: Wendy Robinson, Medical Genetics

Using DNA methylation signatures in placental tissue and cells to gain insight into chorioamnionitis Chaini R Konwar, Magda E Price, Wendy P Robinson Introduction: One of the major causes of spontaneous preterm birth is inflammation of the placenta and associated membranes, known as chorioamnionitis (CA). Identification of DNA methylation (DNAm) signatures in the placenta that reflect in utero conditions may provide candidate markers for earlier diagnosis of inflammation. Inflammation in the placenta is associated with an increase in placental-specific macrophages, Hofbauer cells (HCs). DNAm signatures differ strikingly between different cell lineages and can change with i) gestational age and ii) placental pathology.

We proposed that increases in HC number might be detectable in placentas affected by CA by measuring placental DNAm. Methods: Pooled placental samples (chorionic villi) isolated from the fetal side of the placenta from 12 CA cases and 12 preterm births without other pathology (controls) were run on the Illumina HumanMethylation450 BeadChip array (450K array). Additionally, independent control samples were used to profile DNAm using the 450k array in several pregnancy-associated cells/tissues including HCs, dissected vessel, cord blood monocytes, cytotrophoblast, and chorion.

Results: Hierarchical clustering of DNAm showed HCs clustering most closely with chorion.

We identified 18 differentially methylated sites associated with CA status based on i) statistical significance (False Discovery Rate, <5%); and ii) biological significance (magnitude of methylation difference, Î&#x201D;β>0.1). The majority of these sites were associated with immune-system genes including Orosomucoid 1 which is known to exhibit increased expression in response to infection. We then compared HCs to chorionic villi and identified 10,739 differentially methylated sites. Three of the 18 CA associated DNAm sites were differentially methylated in the same direction in comparison of chorionic villi with HCs. Conclusion: CA-associated placentas showed altered DNAm signatures which are not observed in the absence of inflammation. These changes are consistent with changes in innate immune function and may reflect both increased numbers of immune cells as well as altered function.

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Board # 31 Giulia Muraca, Doctoral Student Supervisor: KS Joseph, Obstetrics & Gynecology

Neonatal and maternal outcomes following attempted operative vaginal delivery at midpelvic station Giulia M Muraca, Yasser Sabr, Sarka Lisonkova, Rollin Brant, Geoffrey W Cundiff, K S Joseph Introduction: We carried out a study to quantify the differences in maternal and neonatal morbidity and mortality associated with attempted midpelvic operative vaginal delivery (OVD), compared with cesarean delivery with labour.

Methods: All singleton, term deliveries in Canada from 2003 to 2012 delivered by midpelvic OVD or cesarean with labour were included after exclusions for known comorbidities. Data were obtained from the Discharge Abstract Database of the Canadian Institutes for Health Information. The primary neonatal outcome included stillbirth, neonatal death, endotracheal intubation, neonatal convulsions and severe birth trauma. The primary maternal outcome included maternal mortality, severe postpartum hemorrhage, transfusion, sepsis, shock, cardiac complications, acute renal failure, obstetric embolism and evacuation of incisional hematoma. Multivariable logistic regression models were fitted to study the adjusted relationships between the determinant variables and the outcomes.

Results: There were 187,234 term, singleton deliveries by midpelvic OVD or cesarean delivery with labour during the study period. The rates of the primary neonatal and maternal outcomes were 1.24% and 1.30%, respectively. Multivariable logistic regression analysis revealed significant increases in the odds of the primary neonatal outcome in babies delivered by OVD compared with those who underwent a cesarean delivery. Among neonates delivered by OVD due to dystocia, the odds of experiencing the primary neonatal outcome was increased with the use of midforceps (Adjusted odds ratio [AOR]=2.99, 95% confidence interval [CI] 2.41-3.71), midpelvic vacuum (AOR=3.18, 95%CI 2.48-4.07), and sequential instrument use (AOR=4.60, 95%CI 3.15-6.72 ) when compared to cesarean deliveries. When OVD was indicated for fetal distress the results were similar with increased odds of neonatal morbidity in babies delivered by midforceps (AOR=1.40, 95%CI 1.23-1.60) and sequential midpelvic OVD (AOR=2.44, 95%CI: 1.94-3.08) compared with those delivered by cesarean. Maternal morbidity was also increased relative to cesarean delivery in the midforceps (AOR=1.29, 95%CI 1.11-1.50) and sequential OVD (AOR=1.45, 95% CI 1.07-1.96) groups while the odds of severe morbidity in women who delivered by midpelvic vacuum was decreased (AOR=0.57, 95%CI 0.47-0.69).

Conclusion: In singleton term pregnancies, midpelvic OVD, with one or two instruments, is associated with an increase in severe neonatal and maternal morbidity compared with cesarean delivery in labour.

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Poster Session Five DOCTORAL STUDENTS Moderator: Tim Oberlander Participants: Hani Bagheri Joshua Brown Harpreet Chhina Kathryn Duff Qianlan Fan Kathleen Kolehmainen Elizabeth Marchant Jean SauvĂŠ

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Board # 32 Hani Bagheri, Doctoral Student Supervisor: Evica Rajcan Separovic, Pathology & Laboratory Medicine

Identifying candidate genes for 2p15p16.1 microdeletion syndrome using clinical, genomic, and functional analysis Hani Bagheri, Chansonette Badduke, Ying Qiao, Rita Colnaghi, Iga Abramowicz, Diana Alcantara, Christopher Dunham, Jiadi Wen, Robert S Wildin, Malgorzata JM Nowaczyk, Jennifer Eichmeyer, Anna Lehman, Bruno Maranda, Sally Martell, Xianghong Shan, Suzanne ME The 2p15p16.1 microdeletion syndrome has a core phenotype consisting of intellectual disability, microcephaly, hypotonia, delayed growth, common craniofacial features, and digital anomalies. So far, more than 20 cases with this syndrome have been reported in literature; however, the size of the deletions and their breakpoints vary making the identification of candidate genes challenging.

Recent reports pointed to four genes (XPO1, USP34, BCL11A and REL) which were included, alone or in combination, in the smallest deletions causing the syndrome. Herein, we describe 8 new cases with 2p15p16.1 deletion and review all published cases. We demonstrate functional deficits for the above 4 candidate genes using patient lymphoblast cell lines (LCLs) and knockdown of their orthologs in zebrafish. All genes were dosage sensitive based on reduced protein expression in LCLs. In addition, deletion of XPO1, a nuclear exporter, co-segregated with nuclear accumulation of one of its cargo molecules (rpS5) in patient LCLs. Other pathways associated with these genes (e.g. NF-kB and Wnt signaling as well as DNA damage response) were not impaired in patient LCLs. Knockdown of xpo1a, rel , bcl11aa and bcl11ab resulted in abnormal zebrafish embryonic development including microcephaly, dysmorphic body, hindered growth, small fins as well as structural brain abnormalities. Our multifaceted analysis strongly implicates XPO1, REL, and BCL11A as candidate genes for the 2p15p16.1 microdeletion syndrome.

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Board # 33 Joshua Brown, Doctoral Student Supervisor: Michael Kobor, Medical Genetics

Distinct functions of Rtt107 in checkpoint regulation and genome maintenance Joshua A R Brown, Michael S Kobor Rtt107 is a budding yeast protein that acts as a scaffold in the DNA damage response (DDR), recruiting key DDR proteins to double-strand breaks. Cells lacking RTT107 (rtt107-ko) exhibit hypersensitivity to DNA damage treatment with MMS and a delayed restart of replication after DNA damage repair. An Rtt107 pool interacting with Dpb11 has been implicated in the prevention of Rad9-mediated Rad53 hyperactivation in a model termed checkpoint dampening. However, the impact of this model remains to be fully explored. Other rtt107-ko phenotypes, such as spontaneous genome instability, could relate to this model or novel function. rtt107-ko strains exhibit DNA damage sensitivity that is partially rescued by reducing Rad53 signalling. We turned to the rad9-ST462,474AA allele to determine if suppression of rtt107ko is due to general effects of reduced checkpoint signalling, or specific to the Rad9-Dpb11 interaction. According to the checkpoint dampening model, Rad9-Dpb11 interaction causes Rad53 hyperactivation in rtt107-ko, and the rad9-ST462,474AA allele abolishes the Rad9-Dpb11 interaction.

This rad9-ST462,474AA allele partially rescued the MMS sensitivity of rtt107-ko strains in a growth assay, but failed to rescue the Rad53 hyperactivation phenotype after MMS treatment. The bulk of Rad53 hyperactivation following MMS treatment therefore appears to be due to other defects of rtt107-ko strains. We speculate that the increased Rad53 activation following MMS treatment primarily results from the higher levels of damage foci seen in rtt107-ko. rtt107-ko exhibits synergistic interactions with the loss of DNA damage tolerance pathways. We examined rtt107-ko suppression by a mutant that broadly reduces Rad53 signalling and by rad9ST462,474AA in strains lacking either TLS or the error-free post-replication repair pathway. Rescue of rtt107-ko by either allele was lost when tolerance pathways were deleted, indicating that these interactions reflect Rtt107 function other than checkpoint regulation. Furthermore, rtt107-ko genome instability was independent of checkpoint regulation and all known partners of Rtt107. Finally, we found that rtt107-ko exhibited a synthetic sick interaction with loss of the Sgs1 helicase that causes greatly enhanced genome instability, reflecting further Rtt107 function in the DDR.

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Board # 34 Harpreet Chhina, Doctoral Student Supervisor: Anthony Cooper, Orthopaedics

Understanding the health impact of lower limb deformities on pediatric patients: An interpretive description qualitative study Harpreet Chhina, Anne Klassen, Jacek Kopec, Anthony Cooper Rigorous, well-documented qualitative research can ensure that new patient reported outcome (PRO) instruments have content validity based on patient’s perspectives. The aim of our study is to understand the impact of lower limb deformities on quality of life (QOL) of pediatric patients, and to use what we discover to develop a new PRO instrument. Face-to- face semi-structured interviews were conducted with 7 children (11 to 18 years) and 9 parents recruited from the BC Children’s Hospital. Interviews were recorded, transcribed verbatim and coded using a line-byline approach. Emerging themes from 16 interviews included the appearance of the leg and the impact of deformity on the child’s physical, social and psychological function. Appearance was an important concern of most children interviewed, though a few children were more concerned about their physical function. Physical limitations identified included: problems with walking, running and standing for longer periods. Social life was affected in terms of going out and making new friends.

Appearance, physical function and social life were substantially affected during the long, arduous treatment phase involving external fixator devices. Patients and their families talked about their experience with the healthcare system and the impact of child’s condition on family life such as frequent hospital visits, financial impact of treatment, having to take time off work, and siblings not getting enough attention. Negative emotions such as anger, frustration, discouragement, fear of teasing, and resentfulness were also described. Additional interviews will be conducted at this site and other sites across Canada, USA, India and Africa.

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Board # 35 Kathryn Duff, Doctoral Student Supervisor: Kevin Harris, Pediatrics

Does a 12-week supervised exercise program reduce aortic stiffness in obese children?

D Kathryn Duff, Astrid M De Souza, James E Potts, Kevin C Harris Background: Overweight children have reduced exercise capacity and increased aortic stiffness conferring an increased risk of future cardiovascular disease. High intensity exercise training has been shown to improve exercise capacity and reverse aortic stiffness in obese adults. Purpose: To describe a novel exercise intervention designed to improve exercise capacity and determine its role in modifying vascular stiffness in obese children.

Methods: Ten to 18 year old children with a BMI â&#x2030;Ľ 97th percentile for age were recruited. Using a prospective, randomized, crossover design, subjects underwent a 12-week, supervised, highintensity, exercise program. During the exercise phase, subjects attended twice-weekly, 75 minute periodized circuit training sessions. Resting echocardiogram and cardiopulmonary treadmill exercise tests were performed before and after both an exercise intervention and 12-week control phase where they received no intervention. There was an 8-week wash-out period between study phases.

Standardized spirometry was used to assess pulmonary mechanics. Physical activity was quantified using tri-axial accelerometry during both study phases.

Results: A total of 15 participants were recruited; of these, we have complete data for 11 subjects (age 14.1+3.0 yrs; ht. 163.5+15.0 cm; wt. 92.8+29.2 kg). Following the exercise intervention, there was a small increase in absolute VO2 (L/min) (pre-intervention 3.276+0.697; post-intervention 3.344+0.931) and exercise capacity (pre-intervention METS 9.49+1.48; post-intervention METS 9.83+1.22; pre-intervention treadmill time 9:13+1.22 mins, post-intervention treadmill time 9:21+1:38 mins). Echocardiogram showed a reduction in pulse wave velocity following the intervention (pre-intervention 440+39 cm/s; post-intervention 416+42 cm/s).

Conclusion: A high intensity exercise training program is feasible in obese children and can improve maximal exercise response. Furthermore, a reduction of pulse wave velocity and improvement in other biophysical properties of the aorta can be achieved with exercise. Challenges in recruitment and retention in this population of children requires consideration.

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Board # 36 Qianlan Fan, Doctoral Student Supervisor: Peter Leung, Obstetrics & Gynecology

Sphingosine-1-phosphate promotes ovarian cancer cell proliferation by disrupting Hippo signaling Qianlan Fan, Yuan Cheng, Hsun-Ming Chang, Masashi Deguchi, Aaron J Hsueh, Peter C K Leung Background: Epithelial ovarian cancers are the most lethal gynecological malignancies in developed countries. Sphingosine-1-phosphate (S1P) is a bioactive lipid that is significantly increased in the ascites fluid of patients with ovarian cancer. S1P has been shown to disrupt growth-suppressive Hippo signaling in several other cancers. Interestingly, Hippo signaling appears to be disrupted in ovarian tumors as levels of the effector Yes-associated protein (YAP) and its downstream targets cysteine-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2) are elevated. This study investigated the roles of S1P and Hippo signaling in ovarian cancer cell proliferation.

Methods: OVCAR3 and SKOV3 ovarian cancer cells were treated alone or in combination with S1P, YAP-complex inhibitor verteporfin (VP), or siRNA targeting CCN1 and CCN2. Subcellular localization of YAP was characterized by immunofluorescent staining. Cell proliferation was measured by MTT assay. Protein and mRNA levels were measured by Western blot and RT-qPCR. Results: S1P treatment increased the proliferation of both OVCAR3 and SKOV3 cells. Treatment of these cells with S1P decreased the phosphorylation of the transcriptional co-activator YAP and promoted its nuclear translocation. Correspondingly, S1P increased the mRNA and protein levels of the YAP-complex target genes CCN1 and CCN2, and these effects were inhibited by the YAPcomplex inhibitor VP. Importantly, S1P-induced cell proliferation was attenuated by individual or combined knockdown of CCN1 and CCN2.

Conclusions: S1P disrupts Hippo signaling by reducing YAP phosphorylation and increasing the expression of CCN1/2, thereby promoting ovarian cancer cell proliferation.

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Board # 37 Kathleen Kolehmainen, Doctoral Student Supervisor: Elizabeth Conibear, Medical Genetics

Adaptors recruit the yeast Chorein homolog Vps13 to distinct membranes in the cell Kathleen Kolehmainen, Waldan Kwong, Leslie Grad, Mike Davey, Cayetana Schluter, Elizabeth Conibear Chorea-acanthocytosis and Cohen syndrome are rare, neurological disorders that arise from loss-of-function mutations in two members of the VPS13 family, VPS13A/Chorein and VPS13B. Chorea-acanthocytosis causes involuntary jerking movements (similar to Huntingtonâ&#x20AC;&#x2122;s disease) and abnormally-shaped red blood cells while features of Cohen syndrome include developmental delay, weak muscle tone, and small head size. Yeast has a single Vps13 protein that shares conserved domains with both VPS13A/Chorein and VPS13B. Recent work has suggested that the spatiotemporal localization of yeast Vps13 to different organelle membranes is largely controlled by adaptor proteins. For example, Spo71, a meiosis-specific adaptor, recruits Vps13 to the prospore membrane where it regulates phosphoinositide 4-phosphate levels. During mitotic growth, Vps13 plays a role in Golgi to vacuole trafficking, however the mechanism of this function is still unknown.

We identified a new Vps13 adaptor that can localize Vps13 during mitotic growth. Additionally, we identified a conserved Vps13 region, the domain of unknown function (DUF) 1162, as the adaptorbinding domain. We showed that this domain is sufficient for binding the two known Vps13 adaptors and has a set of 6 conserved repeats that are important for the trafficking role of Vps13. This study gives novel insights into Vps13 localization and function. Furthermore, it suggests new avenues of research for understanding how VPS13A and B can localize to different membranes in human cells and how each VPS13 gene is linked to a unique disease.

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Board # 38 Elizabeth Marchant, Doctoral Student Supervisor: Pascal Lavoie, Pediatrics

Chemokines and their function in neonatal immune responses Elizabeth A Marchant, Hamid Reza Razzaghian, John J Priatel, Pascal M Lavoie Background: Neonates and young infants are at a higher risk of infections. The human neonatal immune response is functionally distinct from that of adults. Newborns rely heavily on innate and mucosal immunity to defend against infections. Previous work has revealed developmental-specific innate-like functional features of na誰ve CD4+ T cells. However, it is unclear whether other adaptive immune mechanisms may compensate for attenuated innate immune functioning in early life.

Methods: To identify neonatal na誰ve T cell-specific cell surface markers and cytokine signatures, we analyzed published and our genome wide datasets of differential gene expression comparing cord blood and adult peripheral blood na誰ve CD4+ T cells (CD3+CD4+CCR7+CD25-CD45RO-) at baseline and following in vitro stimulation. Candidate cytokine genes were validated at the protein level by flow cytometry and ELISA. Results: We found that CXCL8 is strongly expressed by neonatal T cells. By contrast, we found that CXCL16 is abundantly expressed in both neonatal and adult T cells. In addition, CCL20 RNA expression was elevated in neonatal T cells although CCL20 protein could not be detected by ELISA or flow cytometry. Several potential surface markers specific to neonatal (na誰ve) CD4+ T cells were identified using this approach.

Conclusion: Further experiments are required to demonstrate the functional roles of the chemokines produced by neonatal T cells, and to address the possibility that distinct CCL20 protein isoforms may be expressed by neonatal T cells. Our combinatorial approach will facilitate a comprehensive functional characterization of neonatal CD4+ T cells.

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Board # 39 Jean Sauvé, Doctoral Student Supervisor: Laura Sly, Pediatrics

Tuft cells and their role in intestinal inflammation Jean Philippe Sauvé, Roger Jen, Keith McLarren, Hayley Brugger, Eyler Ngoh, Ted Steiner, Laura Sly Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is characterized by intestinal inflammation. Intestinal epithelial cells play a critical role in mucosal homeostasis and dysregulation of pro-inflammatory epithelial cell function could lead to the intestinal inflammation that characterizes IBD. However, we do not know the events that initiate inflammation or the cell types involved. One type of cell that may play a role is the tuft cell. Tuft cells are the only epithelial cells in the uninflamed intestine that express COX1 and COX2, the rate-limiting enzymes required for production of prostaglandins, like pro-inflammatory PGE2. In our research investigating the lipid phosphatase SHIP, we discovered that tuft cells express SHIP. SHIP deficiency leads to increased PI3-kinase activity in cells resulting in increased cell proliferation, reduced apoptosis, and increased cell activation. SHIP expression is currently believed to be restricted to hematopoietic cells. However, using bone marrow transplantation, we found that tuft cells were not radiosensitive, suggesting that they are not bonemarrow derived and are not hematopoietic in origin.

In addition, SHIP deficient mice develop spontaneous Crohn’s disease-like intestinal inflammation.

Onset of inflammation coincides with the developmental appearance of tuft cells. In wild type mice, tuft cells are found in the lung and ileum, both locations where SHIP deficient mice develop spontaneous inflammation, and we found that tuft cell numbers were increased 6-fold in the inflamed ileum of SHIP deficient mice. Based on this, we hypothesized that SHIP deficient tuft cells may initiate inflammation in the SHIP deficient mouse. We found that SHIP deficient mice had more COX1 positive cells in the ileum and more COX activity and PGE2 in full thickness ileal tissue homogenates, compared to their wild type littermates. Finally, prophylactic inhibition of COX activity with peroxicam, reduced the development of intestinal inflammation in SHIP deficient mice.

Together, these studies suggest a critical role for tuft cells in mucosal homeostasis and may identify novel cellular and biochemical targets to treat intestinal inflammation like that, which characterizes IBD.

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Poster Session Six DOCTORAL STUDENTS Moderator: Brad Hoffman Participants: Nick Dawson Robine Donken Nicole Gladish Lisa Kozicky Nicole Sanford Leah Stiemsma Dominika Nackiewicz Melissa Woodward

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Board # 40 Nick Dawson, Doctoral Student Supervisor: Megan Levings, Surgery

High-dimensional analysis of human regulatory T cells using mass cytometry Nicholas AJ Dawson, Laura Cook, Romy Hoeppli, Anne Pesenacker, Kim Morishita, Raewyn Broady, Megan K Levings Regulatory T cells (Tregs) are critical for maintenance of peripheral tolerance in a variety of tissues.

Evidence that Tregs seem to be a phenotypically diverse population that varies between individuals and tissues suggests that there may be functionally-specialized subsets of Tregs which vary depending on location and/or disease state. We developed a new mass cytometry-based method to measure FOXP3 in combination with 20 other parameters to characterize the phenotype of human Tregs in different tissues, and to enable analysis of antigen-specific cells. We first developed a protocol to detect FOXP3, the Treg lineage-defining transcription factor, via mass cytometry. We found this optimized protocol is more sensitive than commercially-available methodology to detect FOXP3 by mass cytometry and is compatible with staining of other intracellular targets such as cytokines and other transcription factors. To ask how Treg populations differ depending on location and disease state, we stained mononuclear cells from adult peripheral blood, pediatric thymus and cord blood, as well as synovial fluid from pediatric subjects with juvenile idiopathic arthritis with our Treg-specific mass cytometry panel. The resulting data were analyzed using several bioinformatics approaches including viSNE and revealed diversity in the heterogeneity and phenotype of Tregs depending on their origin. The ability to stain FOXP3 using mass cytometry will facilitate the further characterization of Tregs in health versus disease to understand how Tregs are functionally specialized in the context of different tissues and disease.

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Board # 41 Robine Donken, Doctoral Student Supervisor: Simon Dobson, Pediatrics

Are the findings of the QUEST study (Quadrivalent HPV Vaccine Evaluation Study) surveys comparable to other young adolescents in BC Robine Donken, Gordean Bjornson, Kim Marty, Gina Ogilvie, Simon Dobson Background: Representativeness and generalizability are important factors in clinical research. In order to determine the generalizability of the results of the QUEST study (effectiveness of either 2 or 3 doses of HPV vaccine) to girls living in British Columbia (BC), Canada, results from the surveys can be compared to other studies, which are thought to be representative for the general BC population.

Methods: Information on socio-demographic factors, health and sexual behavior among QUEST participants from BC will be compared to the results of the BC Adolescent Health Survey (AHS) from the McCreary Centre for Society. Additionally the data will be compared to the Canadian Sexual Health Survey . Both the baseline and follow up surveys of QUEST participants will be analyzed and compared to the other studies.

Expected results: This project will determine the representativeness of the QUEST BC population to comparable age groups among the general BC population for socio-demographics, health and sexual behavior.

Conclusion: Insight into the representativeness of a research population to the target population is of importance in public health research. This project will help to determine the translatability of the QUEST study.

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Board # 42 Nicole Gladish, Doctoral Student Supervisor: Michael Kobor, Medical Genetics

Human sperm DNA methylation and exposure to childhood abuse Andrea Roberts, Nicole Gladish, Evan Gatev, Meaghan J Jones, Ying Chen, Julia L MacIsaac, Shelley S Tworoger, S Bryn Austin, Jorge Chavarro, Michael S Kobor, Andrea Baccarelli Background: Exposure to early life stress can alter the risk for individuals to develop psychosocial disorders such as major depressive disorder. DNA methylation is an epigenetic mark resulting from the covalent addition of a methyl group on cytosine residues, typically in the context of a CpG. This mark is involved in responding to environmental influences and can result in stable, long term changes to gene expression; thus, it is a unique tool for investigating insults occurring in childhood.

DNA methylation patterns associated with childhood abuse have been observed in several tissues.

In human brain tissue the glucocorticoid receptor gene displays differential methylation and subsequent expression between those who have experienced childhood abuse and those who have not. Determining if DNA methylation signatures exist within gametes is of interest as these are the cells which will be transmitted to future offspring. To date no one has investigated differential DNA methylation associated with childhood abuse in sperm. We hypothesize that childhood abuse alters DNA methylation in sperm with changes persisting into adulthood.

Study: Forty-seven spermatozoa samples from thirty-four participants in Harvard’s Growing Up Today Study were selected for this current analysis. Seventeen individuals were exposed to severe abuse in childhood, while the remaining seventeen were exposed to null or low levels.

Results and Methods: DNA was isolated and genome-wide DNA methylation was measured at 485,512 CpG sites using the Illumina Infinium 450K BeadChip. Principal component analysis was performed to identify sites contributing DNA methylation variation. PC4, which represented 7% of the total DNA methylation variation, was significantly correlated (p < 0.05) with childhood abuse exposure. Differentially methylated regions (DMRs) between childhood abuse exposure groups were investigated using the bioconductor package ‘DMRcate’ revealing 13 statistically significant DMRs at an FDR < 0.05. Linear regression was performed to uncover sites whose methylation status is explained by childhood abuse exposure.

Conclusion: Analysis on our sites of interest uncovered an enrichment of genes related to autism, cancer and neurodegenerative diseases such as Parkinson’s and Alzheimer’s. In the near future, a larger cohort will be used to validate the initial findings of this pilot study.

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Board # 43 Lisa Kozicky, Doctoral Student Supervisor: Laura Sly, Pediatrics

The Fc gamma receptor IIA (Fc gamma RIIa) gene variant increases macrophage inflammatory responses and reduces antibody-mediated anti-inflammatory macrophage activation Lisa Kozicky, Zheng Yu Zhao, Susan Menzies, Kiera Harnden, Laura M Sly Inflammatory Bowel Disease (IBD) is an immune-mediated disease characterized by inflammation along the gastrointestinal tract. Anti-TNF alpha antibodies have revolutionized IBD treatment but 10% of patients are unresponsive to therapy and we can not predict which patients will respond.

A gene variant in the Fc gamma RIIa, an antibody (IgG) receptor expressed on macrophages, predisposes people to develop IBD and has been linked to a failure to respond to anti-TNF alpha therapy. We have reported that macrophages treated with IgGs produce large amounts of the antiinflammatory cytokine, IL-10, in response to inflammatory stimuli. Based on this, we asked whether the Fc gamma RIIa risk variant acts by reducing anti-inflammatory Fc gamma receptor-mediated macrophage activation. Healthy control study participants were genotyped for the Fc gamma RIIa gene variant and their peripheral blood monocyte-derived macrophages (MDMs) were stimulated with lipopolysaccharide (LPS), pooled IgGs, or both, in the presence or absence of blocking antibodies to Fc gamma receptors. Macrophages from participants with the Fc gamma RIIa risk variant produced more pro-inflammatory cytokines in response to LPS and were less able to reduce pro-inflammatory cytokine production when treated with IgGs. Fc gamma RI, Fc gamma RIIb and Fc gamma RIII were required to limit immune responses. Intriguingly, the Fc gamma RIIa susceptibility gene variant changes this receptor from a low to a high affinity receptor. Thus, our data are consistent with a model in which the high affinity Fc gamma RIIa risk variant sequesters antibodies from the Fc gamma receptors that mediate anti-inflammatory macrophage activation. In future studies, we will investigate whether the Fc gamma RIIa gene variant can be used to predict whether a patient will respond to anti-TNF alpha therapy.

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Board # 44 Nicole Sanford, Doctoral Student Supervisor: Todd Woodward, Psychiatry

Abnormal brain activation during internal speech in schizophrenia: A multi-experiment fMRI analysis Nicole Sanford, Todd S Woodward Background: Functional brain networks associated with internal thought and maintenance of information have been implicated in schizophrenia, especially patients with hallucinations. However, comparing networks between different functional neuroimaging studies is imprecise. The present study used a multivariate approach to investigate task-correlated brain networks common to working memory and language tasks. We expected schizophrenia patients to exhibit response abnormalities in networks underlying internal speech and working memory.

Methods: 43 schizophrenia patients, 38 bipolar disorder patients, and 53 healthy controls participated in one of two functional magnetic resonance imaging (fMRI) tasks: a thought-generation task (TGT) in which participants either listened to or internally generated a definition of a noun, and a working memory task (WM) in which participants had to remember a string of letters over a four second delay or no delay. Constrained principal component analysis and mixed-model ANOVA were used to extract task-correlated networks and investigate effects related to group, task conditions, and post-stimulus time.

Results: Five networks were extracted, with distinct spatial configurations and response shapes.

Network five, which included activations in dorsal anterior cingulate, insula, Brocaâ&#x20AC;&#x2122;s area, and visual cortex, appeared to be related to internal speech. This network was distinctly correlated with the delay phase of WM (i.e., when internal rehearsal of the letters is engaged) and with thought generation in TGT, and was inactive in both tasks when effortful inner speech was not required.

Notably, recently-hallucinating schizophrenia patients exhibited suppression of this network during TGT, especially immediately before and after the response activation.

Conclusions: Hyper-suppression of an internal speech-related network during the â&#x20AC;&#x153;task offâ&#x20AC;? phase in patients who experience auditory hallucinations could be explained by a neurological distinction between controlled internal speech and spontaneous hallucinatory voices, with the latter suppressing the former in the absence of explicit cognitive demands. A potential clinical implication is that the possibility of strengthening this network through cognitive training could benefit hallucinating patients. Combining data from multiple studies allowed for a direct evaluation of spatial and temporal replication (and non-replication) of networks involved in the two tasks, which is a methodological advance that cannot be adequately achieved by a side-by-side comparison.

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Board # 45 Leah Stiemsma, Doctoral Student Supervisor: Stuart Turvey, Pediatrics

The intestinal microbiome in early life asthma Leah T Stiemsma, Marie-Claire Arrieta, Pedro A Dimitriu, Jasmine Cheng, Lisa Thorson, Diana L Lefebvre, Padmaja Subbarao, Piush Mandhane, Allan Becker, Malcolm Sears, Tobias R Kollmann, the CHILD Study Investigators, William W Mohn, B Brett Finlay, Stuart Turvey Background: Asthma is a chronic disease of the airway most prevalent in children. In the search for preventative treatments against asthma, the gut microbiota has been identified as a potential therapeutic target. Our group recently identified four bacterial genera, Faecalibacterium, Lachnospira, Veillonella, and Rothia (FLVR), associated with decreased risk of asthma development in infants (Sci Trans Med, Sep. 2015). Here, we describe results from the first validation study assessing the abundance of the FLVR bacteria and a newly characterized Clostridium species among children with early life asthma.

Methods: Children 3 â&#x20AC;&#x201C; 4 years old enrolled in the Canadian Healthy Infant Longitudinal Development (CHILD) study were classified as asthmatic (n = 39, physician-diagnosed or prescribed inhaled asthma medications) or matched healthy controls (n = 38). 16S rRNA sequencing and quantitative PCR (qPCR) was used to analyze the composition of the 3-month and 1-year gut microbiome of these children.

Results: 16S sequence and qPCR analysis identified significant shifts in the abundance of the genus, Lachnospira (L), and the species, Clostridium neonatale (C), in the 3-month and 1-year gut microbiome of asthmatics compared to controls. Quartile analysis of these results revealed a negative association between the ratio of these two bacteria (L/C) and asthma risk (calculated by odds ratios).

Conclusions: Shifts in the relative abundances of Lachnospira and Clostridium neonatale in the first year of life are associated with early life asthma in 3 - 4 year old children. These taxa represent potential biomarkers and therapeutic targets for prevention of this burdensome disease.

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Board # 46 Dominika Nackiewicz, Doctoral Student Supervisor: Bruce Verchere, Surgery

Beta cell death promotes an anti-inflammatory and regenerative phenotype in resident islet macrophages D Nackiewicz, M Dan, P Yoganathan, M Speck, S Chow, C B Verchere, J A Ehses Macrophages contribute to the pro-inflammatory milieu of the diabetic islet as well as support beta cell replication in models of pancreatic and beta cell regeneration. It is well known that apoptotic cells promote immunosuppressive effects in macrophages, and apoptosis is thought to be the main mechanism of beta cell death in type 2 diabetes. Therefore, we hypothesized that in the absence of islet amyloid polypeptide, beta cell death would skew islet macrophages to an anti-inflammatory and regenerative phenotype. Various types of alternatively activated macrophages were generated in vitro, with some secreting decreased pro-inflammatory cytokines and increased growth factors such as PDGF-AA and IGF-1. In response to streptozotocin (STZ)-induced beta cell death in vitro islet macrophages skewed to an anti-inflammatory and regenerative phenotype, independent of any direct effect of STZ on macrophages. Similar results were observed in vivo in sorted islet macrophages following STZ-induced beta cell death (decreased Il1b, Tnfa, increased Il1rn, Igf1, Tgfbi), with the timing of macrophage skewing correlated with increased numbers of TUNEL+ beta cells. Indeed, adoptive transfer of unskewed macrophages decreased STZ-induced hyperglycemia and increased non-fasting insulin levels, supporting the finding that apoptotic beta cell death skews macrophages to a beneficial phenotype. Finally, resident islet macrophages in both the diabetic GK rat and db/db BKS mouse were skewed to an anti-inflammatory and regenerative phenotype. Our data demonstrate that resident islet macrophages skew to an anti-inflammatory and regenerative phenotype following apoptotic beta cell death and in rodent models of type 2 diabetes. Increasing the number or functionality of these macrophages may be used as an approach to preserve functional beta cell mass in individuals with diabetes.

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Board # 47 Melissa Woodward, Doctoral Student Supervisor: Donna Lang, Radiology

Prevalence of incidental findings in a multi-diagnosis psychosis, addiction and infection population in Vancouverâ&#x20AC;&#x2122;s Downtown Eastside Melissa Woodward, Alexandra Vertinsky, Manraj Heran, Jason Chew, Allen Thornton, Kristina Gicas, Heather Baitz, Chantelle Giesbrecht, Nena Wang, Tiffany Oâ&#x20AC;&#x2122;Connor, Kristina Walclawik, Alexander Rauscher, G MacEwan, Fidel Vila-Rodgriguez, Olga Leonova, William Honer, Geoffrey Smith, Taylor Willi,Alasdair Barr, Ric Procyshyn, Donna Lang The Hotel Study is a longitudinal epidemiological investigation of socially disadvantaged downtown eastside residents and includes psychiatric, psycho-social and biomedical assessments. The Downtown Eastside neighbourhood of Vancouver has the largest open-air illicit drug market in North America and the largest rate of homelessness in the city. Neuroimaging studies have shown abnormalities that show long-term drug use may lead to physiological changes and neural damage associated with cognitive impairment. As part of this study, high-resolution brain magnetic resonance imaging was obtained yearly and images were reviewed by a neuroradiologist. While incidental findings are relatively common in the general population (5-20%), preliminary analysis indicated that this population has a significantly elevated rate of total numbers of incidental findings (>80), including cerebrovascular abnormalities (e.g. aneurysms, hemorrhages and infarcts), traumatic brain injuries and parenchymal volume loss greater than expected for age. Both life history and chronic illicit substance use are thought to contribute to these phenomena. We predict adverse effects on cognition are predict in individuals with a greater burden of neurological damage. The co-morbidity of neuropathologies parallels the co-morbidity of general health issues. Better understanding of these neuropathologies may provide evidence of new approaches to treatment strategies.

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Poster Session Seven DOCTORAL STUDENTS Moderator: Christine Tipper Participants: Sarah Anderson Stephanie Campbell Tony Lok Heng Chu Christina Michalski Mahdis Monajemi Samantha Wilson Olivia Wong

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Board # 48 Sarah Anderson, Doctoral Student Supervisor: Robert McMahon, Psychology

Sex differences in the association between callous-unemotional traits and pregnancy Sarah L Anderson, Yao Zheng, Robert J McMahon The relationship between conduct problems and risky sexual behaviour has been explored previously; however, how callous-unemotional (CU) traits (e.g., lack of empathy, lack of guilt, and egocentricity) and the interaction between conduct disorder (CD) symptoms and CU traits contribute to risky sexual behaviour has been explored infrequently. To address this gap in the literature, this study focused on a combined high-risk and normative sample of individuals to investigate the role that CD symptoms, CU traits, and their interaction play in predicting pregnancy in adolescence. Participants came from the control schools of a longitudinal multisite investigation of the development and prevention of childhood conduct problems, the Fast Track project. Of the overall sample (N = 683), 41.7% (n = 285) were female. The sample was racially diverse: 47.4% were African American (n = 324), 49.3% were Anglo American (n = 337), and 3.2% were Hispanic, Asian, Native American, or â&#x20AC;&#x153;otherâ&#x20AC;? (n = 22). In this study, pregnancy was operationalized as a dichotomous variable, such that pregnancy (i.e., experiencing for females or causing for males) during high school was scored as 1 and absence of pregnancy or pregnancy post-high school was scored as 0. Sex, race, severity-of-risk, site of data collection, age, socioeconomic status, ADHD symptoms, and substance use in grade 7 were controlled for. It was found that CU traits significantly predicted pregnancy (B = 1.03; p < 0.05). Exploratory analyses were conducted to investigate sex differences in the relationship between CD symptoms, CU traits, and their interaction on pregnancy.

CU traits predicted pregnancy among males (B = 1.32; p < 0.05), but not females. CD symptoms did not predict pregnancy among males or females. This study has diverse implications for informing prevention programs targeting adolescent pregnancy, and provides meaningful information regarding the importance of CU traits and sex in understanding health-risking behaviour.

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Board # 49 Stephanie Campbell, Doctoral Student Supervisor: Brad Hoffman, Surgery

Trithorax group complexes are essential for pancreatic endocrine and exocrine cell specification Stephanie A Campbell, Cassandra L McDonald, Brad G Hoffman Background and Aims: All cells of the pancreas arise from a common progenitor cell niche that differentiates into endocrine, exocrine and duct cell lineages. Activation of various transcription factors is critical for this process but their exact regulation is largely unknown. To address this, we compared the chromatin state of cis-regulatory regions associated with pancreas critical transcription factors in mouse islets and ES cells and found that the majority of these regions need to gain activating histone marks during specification. We hypothesize that the Trithorax group (TrxG) complexes that deposit histone methylation are necessary for the appropriate activation of transcription factors critical to progenitor specification during pancreas development.

Materials and Methods: To test our hypothesis in vitro, we suppressed the core TrxG protein Wdr5 by shWdr5 in spheroids. We also targeted the TrxG core protein Dpy30 in vivo and generated a Pdx1Cre-driven Dpy30 knockout mouse (Dpy30pko).

Results: Strikingly, shWdr5 almost abrogated expression of markers for endocrine (Ngn3, Ins1, Ins2, Gcg) and exocrine (Amy1, Cpa1, Cpa2) cells. Markers of pancreas progenitors (Pdx1, Sox9, Foxa2) and of duct cells (Muc4, Muc20, Reg3b) were unaffected. Interestingly, the embryonic pancreas of Dpy30pko mice showed a similar deficiency in endocrine and exocrine cell development, while ductal markers were enhanced.

Conclusions: Our results suggest that Wdr5 and Dpy30 are essential for pancreas progenitors to be specified into endocrine and exocrine, but not duct, cell lineages. This implies that in pancreas progenitors, factors necessary for duct cell specification have already attained histone methylation at their regulatory regions, while factors necessary for endocrine and/or exocrine specification have not.

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Board # 50 Tony Lok Heng Chu, Doctoral Student Supervisor: Christopher Maxwell, Pediatrics

Cell cycle regulated centrosome orientation and centrosome nucleation during directed migration requires Aurora kinase A Tony LH Chu, Lixin Zhou, Jennifer Won, Pooja Mohan, Oksana Nemirovsky, Abbas Fotovati, Torsten Nielsen, Nelly Pante, Christopher A Maxwell Problem: Metastasis accounts for 90% of deaths from carcinomas.

Background: Epithelial cells must front-rear polarize and reorganize the microtubule cytoskeleton to move and metastasize. In mitotic cells, these processes require Aurora kinase A (AURKA), which is optimally active when complexed with TPX2. Mitotic location of TPX2 requires RHAMM, which is a substrate for AURKA. During interphase, phosphorylated RHAMM localizes to the nucleus, the site of TPX2. Silencing RHAMM alters the nuclear localization of TPX2, which suggests RHAMM or phosphorylated RHAMM may also control TPX2 location and AURKA activity in non-mitotic cells.

Non-mitotic functions for AURKA are emerging but we do not know which molecules control its activity or whether it regulates the polarity or migration of breast cancer cells.

Results: We studied the AURKA-TPX2-RHAMM signaling axis in mammary (MCF10A and nMUMG) and HeLa cells. Silencing RHAMM altered TPX2 location as indicated by immunofluorescence and immuno-EM, which located TPX2 to the nuclear envelope and nuclear pore basket. Nuclear import of recombinant TPX2 was attenuated in RHAMM silenced cells and nuclear envelope accumulation was elevated. In parallel studies of scratch wound assays, migratory cells front-polarized centrosomes, which correlated with G2 cell cycle phase, phosphorylated AURKA and elevated microtubule nucleation at centrosomes. Small molecule inhibition of Aurora kinase activity impaired centrosome polarity and retarded the kinetics of cell migration. Finally, in a large breast cancer tissue microarray (n= 3,175), the abundance of phosphorylated RHAMM predicted overall and relapse-free survival in ER-negative, basal-subtype, and triple negative breast tumors.

Conclusion: The AURKA-TPX2-RHAMM axis regulates centrosome polarity, microtubule nucleation and directional cell migration while phosphorylated RHAMM predicts survival in aggressive forms of breast cancer. Future studies will assess the stability of TPX2 in RHAMM silenced cells and the role of phosphorylated RHAMM as a putative negative feedback regulator for AURKA activity.

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Board # 51 Christina Michalski, Doctoral Student Supervisor: Pascal Lavoie, Pediatrics

Assessing the potential for innate immune memory of cord blood monocytes Christina Michalski, Bernard Kan, Pascal M Lavoie Neonates are at a high risk of fungal infections, especially those born prematurely, in part due to markedly reduced immune defenses to Candida. We have shown that monocytes from premature neonates express Dectin-1, the receptor recognizing the fungal cell wall component β-glucan, but lack functional response of this receptor through the Syk pathway due to a lack of expression of the MALT1 signalosome at the protein level. Recently, it has been discovered that innate immune responses in monocytes and dendritic cells can be enhanced through “immune training” that is induced by low doses of β-glucan and mediated through the Dectin-1 alternate RAF pathway.

The function of the RAF pathway has never been investigated in neonatal monocytes. Here, we investigated the hypothesis that monocytes from cord blood of prematurely born neonates can be trained to produce enhanced responses to Toll-like receptor agonists following low dose Dectin-1 stimulation. We also hypothesize that the function of the Dectin-1 RAF pathway is preserved in neonatal monocytes. Monocytes isolated from cord blood or adult peripheral blood were analyzed by genome-wide transcriptomic arrays to examine expression of RAF/Syk mediators. Protein expression was also examined by western blot. Finally, cells were subjected to training using low doses of β-glucan followed by five days resting period and re-stimulation with TLR4 or TLR7/8 ligands to assess pro-inflammatory cytokine secretion by ELISA. Our preliminary data shows that immune training can be recapitulated in adult monocytes, and that preterm monocytes display a metabolic signature (transcriptomic) consistent with a “trainable” state. Our ongoing studies will determine whether neonatal monocytes from premature neonates can be trained similarly. Assessing the potential for innate immune memory in monocytes from infants born prematurely is of high interest, as this mechanism might aid in developing therapeutics reversing the immunoparalysis of premature neonates.

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Board # 52 Mahdis Monajemi, Doctoral Student Supervisor: Laura Sly, Pediatrics

The role of MALT1 in macrophages Mahdis Monajemi, Susan C Menzies, Laura M Sly MALT1 is a signalling molecule that acts as both a protein and a protease. MALT1 plays a key role in Nuclear Factor kappa B (NF-ÎşB) activation downstream of the B and T cell receptor causing lymphocyte activation and proliferation. MALT1 also plays a role in macrophage activation by acting downstream of dectin-1, dectin-2, toll-like receptor 2/6 (TLR2/6), and TLR4 signalling pathways.

A key role for MALT1 in intestinal homeostasis and inflammation was recently demonstrated because patients deficient in MALT1 develop severe combined immunodeficiency accompanied by dramatic inflammation along the gastrointestinal tract. MALT1 contribution to inflammation has been attributed to B and T cells. However, the role of MALT1 in macrophage-mediated inflammation has not been investigated. Based on this, we hypothesize that MALT1 deficiency causes inflammation by increasing macrophage inflammatory responses. Our results show that MALT1 deficient murine macrophages have a lower inflammatory response than wild type macrophages. In contrast, inhibiting MALT1 activity increases inflammatory cytokine production by murine macrophages in response to stimulation. We also found that stimulation of macrophages with TLR4 ligand increases both MALT1 expression and its activity in these cells.

Taken together, our studies are consistent with a model in which MALT1 activity reduces proinflammatory macrophage responses but its scaffolding function increases macrophage inflammatory responses. In future studies, we will investigate the cell-specific contribution of MALT1 deficient macrophages to inflammatory disease by depleting macrophages and using mice with myeloidspecific MALT1 deficiency. These studies will provide critical information about the cell specific role of MALT1 and possible side effects of MALT1 inhibitors currently used for lymphoma treatment.

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Board # 53 Samantha Wilson, Doctoral Student Supervisor: Wendy Robinson, Medical Genetics

Placental telomere length decline with gestational age differs by sex and TERT, DNMT1, and DNMT3A DNA methylation Samantha L Wilson, Yao Liu, Wendy P Robinson Introduction: Telomere length (TL) heritability has been estimated between 30-80%. However, few genetic variants have been associated with TL. It has been proposed that unexplained heritability of TL may be driven by epigenetic variation. We therefore investigated the relationship between TL and DNA methylation (DNAm) within the placenta. Furthermore, TL has been reported to be significantly shorter in placentas from pregnancies complicated by preeclampsia (PE) and/or intrauterine growth restriction (IUGR). This has been attributed to oxidative stress that occurs in PE/IUGR. However, such effects could alternatively be due to normal variation in TL related to gestational age (GA) or fetal sex. Therefore we also assessed TL in early-onset PE (EOPE), late-onset PE (LOPE), IUGR and control placentas, taking into account all confounding factors.

Methods: Average TL in 92 controls, 21 EOPE, 18 LOPE, and 9 IUGR placentas were measured by qPCR. Thirteen Controls, 20 EOPE, 17 LOPE, and 8 IUGR samples were also run on the Illumina 450K array, measuring DNAm across the genome. ANOVA was used to compare TL between EOPE, LOPE, and IUGR to controls. Linear regression correcting for GA and sex assessed the association between TL and DNAm with a targeted approach (TERC, TERT, DNMT1, DNMT3a, DNMT3b), and array-wide analysis.

Results: Male sex and increasing GA were associated with shorter TL. Our targeted analysis revealed associations of TL with DNAm at TERT, DNMT1, and DNMT3a. Using an array wide approach, no additional sites of DNAm were identified as associated with TL. No significant difference in TL was observed between EOPE, LOPE, and IUGR placentas compared to controls after correction for fetal sex and GA. Conclusions: Variability in TL may be influenced by alterations in DNAm at TERT, DNMT1, and DNMT3a, but we could not confirm previous reports of an association with EOPE, LOPE, or IUGR.

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Board # 54 Olivia Wong, Doctoral Student Supervisor: Michael Kobor, Medical Genetics

Elucidating the paradoxical role of the histone variant H2A.Z and its depositor SWR1-C Olivia Wong, Michael S Kobor In eukaryotes, chromatin remodelling is essential for nuclear processes. Multiple mechanisms function to generate local alterations in chromatin structure, thus changing the accessibility of DNA to DNA binding proteins. One mechanism is the incorporation of the highly conserved histone variant H2A.Z into nucleosomes, where H2A.Z is found to be involved in various cellular processes.

In Saccharomyces cerevisiae H2A.Z is incorporated by an ATP-dependent chromatin remodeling complex, SWR1-C, at specific genomic locations such as nucleosomes flanking transcription start sites. As shown previously, loss of H2A.Z results in severe growth defects under genotoxic conditions. However, despite the role of Swr1 as the catalytic subunit of SWR1-C, loss of Swr1 results in a significantly less severe growth defect than loss of H2A.Z. Most interestingly, cells that lack both H2A.Z and Swr1 display growth phenotypes resembling those of cells lacking only Swr1.

This genetic interaction suggests more nuanced roles for Swr1 and H2A.Z. To understand the role and relationship between H2A.Z and Swr1, we will study their function as it relates to transcription regulation. In particular, we will study the role of H2A.Z and Swr1 in the transcriptional response to heat shock. Using an established heat shock system, we observed a trend in transcription of representative heat shock-responsive genes that complement the growth phenotypes described above upon stress onset. Next we will map the transcription dynamics of these representative genes at stress recovery as well as mapping H2A.Z occupancy at promoters of these genes to understand H2A.Z dynamics in stress onset and recovery.

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Poster Session Eight

POSTDOCTORAL FELLOW, SUBSPECIALTY RESIDENT OR FELLOW Moderator: Clara van Karnebeek Participants: Liron Borenstein-Levin Sarah Hutchison Emily Kieran Manon Ranger Rebecca Ronsley Veronica Schiariti

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Board # 55 Liron Borenstein-Levin, Subspecialty Resident or Fellow Supervisor: Alfonso Solimano, Pediatrics

The SPO2 histogram classification - A clinical language for SPO2 targeting and measuring oxygenation instability Liron Borenstein-Levin, Laura Konikoff, Alfonso Solimano Background: Optimal SPO2 targeting remains an elusive goal in the NICU. Narrow SPO2 targets of 90-95% may decrease mortality, and of 85-89% may decrease ROP, however, narrow ranges are difficult to achieve and maintain. Konikoff et al (PAS 2015) classified 12-hour SPO2 histograms in a cross sectional study, showing a high prevalence of SPO2 instability. Poets has reported (JAMA 2015) that prolonged hypoxemic episodes are associated with adverse 18 month outcomes.

Objective: To test the use and acceptability of the classification system of SPO2 histograms in a large cohort, and determine the prevalence and significance of each histogram type in a cross sectional study.

Design/Methods: 12-hour SPO2 histograms from the Phillips Intellivue MX800 monitors were printed twice daily for all infants<34 weeks gestation on respiratory support on day one. Excluded were infants with anomalies. Each histogram was classified into one of five types as described in PAS 2015, based on the number of cumulative bars (Δ) between 10% and 90%.

Results: 3081 consecutive histograms of 58 infants were analysed. Mean birth GA was 29w, BW 1329g. The average daily prevalence of histogram Types 1 to 5 was 34%, 34%, 27%, 2% and 3%; for infants in oxygen, prevalence was 6%, 34%, 50%, 4% and 7%. Histogram type did not affect the SPO2 median in infants in oxygen, which was 94±2%, 93±2%, 92±2%, 93±1% and 92±1% respectively. Time with SPO2 90 to 95% was only 62% for type 1 or 2, 48% for type 3 and 37% for types 4 and 5. Time with SPO2>95% was 20 to 35% for all histograms for infants in oxygen. Time with SPO2 <85% in Types 3 through 5 was 12±5, 15±2 and 23±4%, and with SPO2 <80% was 5±3, 8±1 and 13±3%.

Conclusions: Despite careful SPO2 targeting and achieving median SPO2 within range, oxygen instability is common and narrow SPO2 ranges difficult to achieve. SPO2 histograms provide clinicians with the clarity of a common language that aids targeting and reveals the presence and magnitude of oxygenation instability.

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Board # 56 Sarah Hutchison, Postdoctoral Fellow Supervisor: Tim Oberlander, Pediatrics

Explicit and implicit weight stigma in young children Sarah M Hutchison, Ulrich MĂźller Explicit Weight stigma (WS) tasks require individuals to make evaluations (e.g., self-report) about people who are overweight/ obese, which can be influenced by social desirability. Implicit WS tasks reduce the role of social desirability, such as the WS Implicit Association Test (IAT), which compares response speeds to fat and thin stimuli. Our goals for the study were to: 1) examine the association between two explicit measures of WS to determine if they are tapping into a similar underlying construct; 2) extend downwards the age range used in previous studies measuring explicit and implicit WS; and 3) examine age-related differences in explicit and implicit WS. We administered the Ant-fat Prejudice task, Friendship Selection task, and a WS IAT to eighty-four 4- to 7-year olds.

Results showed that: 1) the two measures of explicit WS were associated, r = .27, p < .05; 2) children demonstrated both explicit and implicit WS; and 3) age accounted for 10.6% of the variance in explicit WS, F (1, 82) = 9.75, p < .01, and age accounted for 11.2% of the variance in the WS IAT, F (1, 63) = 7.95, p < .01. These findings suggest the importance of early intervention to reduce WS.

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Board # 57 Emily Kieran, Subspecialty Resident or Fellow Supervisor: Alfonso Solimano, Pediatrics

How reliable is the “guarantee” in high frequency oscillatory ventilation with volume guarantee?

Emily Kieran, Jessy Jagpal, Gary Stacey, Laura Yong, Alfonso Solimano Background: In High frequency oscillatory ventilation (HFO), the rate of CO2 removal (DCO2) [gas transport coefficient] is proportional to tidal volume (VtHFO) squared and to frequency (fHFO), at a constant dead space: DCO2 (in mL2/sec) = (VtHFO)2 x fHFO. HFO volume guarantee (HFO-VG) is a new mode in the Drager VN500 that is meant to stabilize the DCO2 by automatically regulating delta-P (∆P) to maintain the set VtHFO. Objectives: We conducted a benchmarking study in order to determine the effectiveness and performance range of HFO-VG. Method: We used a neonatal test lung, and VtHFO of 4 mL, to test the VN500 in HFO-VG simultaneously against the Biomedical Engineering IMT Medical Flow Analyzer PF300, and the Bunnel Jet ventilator (BJV) (with a 3.5 Life Port adaptor) whose PEEP scale accurately detects HFO waveforms with negative trough pressure. For calibration we generated HFO with a Sensormedics 3100A varying ∆P from 10 to 50 cmH2O, MAP of 10 to 14 cmH2O and fHFO 6 to 14Hz. We analyzed the VN500 ∆P, VtHFO, and DCO2 over a fHFO of 6 to 14Hz, at i:e ratios of 1:2 and 1:1, and measured the peak and trough pressure generated by the VN500 as it tried to guarantee the VtHFOVG of 4 mL. Results: Peak, ∆P and trough pressures measured by the PF300 and BJV correlated with an R2 > 0.9, and had a Bland Altman mean diff < 1cmH2O. VtHFO was “guaranteed” by automatic adjusting of ∆P, but only within an effective operational range, which in our model plateaued at 10 hertz. Beyond that range the VN 500 was unable to increase the ∆P, VtHFO could not be guaranteed and DCO2 rapidly decreased. Changing the i:e ratio from 1:2 to 1:1 extended the “useful” fHFO range at which VtHF could be guaranteed, however the ∆P needed to meet the set VtHFO mostly increased by generating negative trough pressure.

Conclusions: HFO-VG has a tight operational range, which depends on the physics of HFO, equipment design, fHFO and pulmonary mechanics. Understanding the physical limits of HFO-VG will aid the clinical testing of this experimental mode of HFO.

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Board # 58 Manon Ranger, Postdoctoral Fellow Supervisor: Ruth E Grunau, Pediatrics

Neonatal repeated sucrose exposure induces wide spread reduced white matter in mice Manon Ranger, Sophie Tremblay, Jacob Ellegood, Jason P Lerch, Liisa Holsti, Daniel Goldowitz, Ruth E Grunau Background: Sucrose is standard care for pain relief for minor procedures on preterm infants in the NICU. Clinical equipoise no longer exists for a randomized controlled trial of sucrose in human infants. No human or animal studies of effects of early repeated sucrose exposure on long-term brain development have been done in the context of pain.

Objective: To examine effects of repeated neonatal sucrose treatment before an intervention on long-term brain development in mice.

Design & Methods: Neonatal C57Bl/6J mice (N=109, 46% male) were randomly assigned to one of 2 treatments (sucrose vs water) and one of 3 interventions (needle-prick, touch, handling). Mice received 10 interventions over a 12h period (daytime) daily from postnatal day 1 to 6 (P1-P6).

A single dose of 24% sucrose (0.1-0.2mg of sucrose/g weight) or water was given orally 2 min before each intervention. At P85-95, mice were anesthetized and intracardially perfused with 4% paraformaldehyde (PFA) containing 2mM ProHance. The brains and remaining skull structures were scanned using a multi-channel 7.0 Tesla MRI. Sixteen custom-built solenoid coils were used to image the brains in parallel. Volumes of 159 independent brain regions were obtained using advanced registration methods with a pre-existing classified atlas. ANOVA was used to assess group differences, and false discovery rate (FDR<5%) to correct for multiple comparisons.

Results: Mice repetitively exposed to sucrose (n=56) compared to water (n=53) on P1-P6 had significantly smaller volumes in large white matter structures especially in the corpus callosum, stria terminalis, and fimbria (p<0.0001; FDR<4%). We also found significantly smaller volumes in cortical and subcortical structures which included the cerebellum and hippocampus (p<0.0001; FDR<5%).

These significant changes in adult brain were found irrespective of the type of intervention in the neonatal period.

Conclusions: In a mouse pain model that closely mimics daily NICU care, early repetitive exposure to sucrose before needle-prick, touch or handling induced significant reductions in specific regional white and grey matter seen in adult mice. Evidence of long-term adverse effects of repetitive sucrose exposure during the neonatal period of rapid brain development is a concern.

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Board # 59 Rebecca Ronsley, Resident Supervisor: Dina Panagiotopoulos, Pediatrics

High prevalence of acute kidney injury in children with type 1 diabetes presenting in diabetic ketoacidosis Rebecca Ronsley, Brenden Hursh, Claire Ronsley, Cherry Mammen, Constadina Panagiotopoulos Objective: To determine the prevalence of acute kidney injury (AKI) occurring in children â&#x2030;¤18 years with type 1 diabetes (T1D) presenting in diabetic ketoacidosis (DKA).

Methods: This was a retrospective chart review of all DKA admissions to BC Childrenâ&#x20AC;&#x2122;s Hospital between 09/2008 and12/2013. The primary outcome measure, AKI, was defined using the Kidney Disease/Improving Global Outcomes criteria. An estimated baseline glomerular filtration rate of 120 ml/min/1.73m2 was used to calculate baseline serum creatinine as prior creatinine was not available in all patients. Data was compared between those that developed severe AKI (stage 2 or greater) versus those with mild (stage 1) or no AKI. Results: Of the 165 eligible admissions, AKI was documented in 64% of children at presentation; of these, 36.2% met criteria for stage 1 AKI, 47.6% for stage 2 AKI, and 16.2% for stage 3 AKI, with 3 requiring dialysis. On presentation, severe AKI subjects had a significantly lower serum bicarbonate (OR 0.17 (CI: 0.05, 0.57), p=0.004), and a higher heart rate (OR 1.19 (CI: 1.06, 1.33), p=0.003). There was a trend for higher corrected sodium in severe AKI subjects. Twenty-nine percent of severe AKI subjects were oliguric (urine output <1cc/kg/hr for >12 hours) during the admission. By discharge, stage 2/3 AKI subjects had a greater mean % weight change (8.9 + 6.03% vs 6.7 + 6.81, p=0.038) compared with normal or stage 1 AKI subjects.

Conclusions: This is the first report to document a high prevalence of AKI in children presenting in DKA, with 40% having moderate or severe AKI. Given that AKI carries a risk for chronic kidney disease, protocols for early AKI identification and adequate fluid resuscitation need to be developed to ensure resolution of impaired renal function. Further prospective studies are required to understand the risk factors and long-term implications of these findings.

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Board # 60 Veronica Schiariti, Postdoctoral Fellow Supervisor: Tim Oberlander, Pediatrics

What do pediatric pain tools really measure?: Content analysis using the International Classification of Functioning, Disability and Health Veronica Schiariti, Tim Oberlander Introduction: Pain is an important factor that affects functioning and quality of life of children and youth with Cerebral Palsy (CP). There is a wide range of pain prevalence in pediatric studies in CP, ranging from 14% to 73%. However, pain in CP is under recognized, and most importantly there is no consensus on how to assess pain in children and youth with CP. The newly developed International Classification of Functioning, Disability and Health (ICF) Core Sets for children and youth with CP guide professionals in selecting the most appropriate measures to comprehensively capture information regarding this population.

Objectives: 1) to identify measures used to address pain in children and youth with CP, and 2) to characterize the content of each measure using the ICF Core Sets for children and youth with CP as a framework.

Methods: A systematic review of the literature was completed using multiple search engines likely to capture studies involving children with CP published between1998-2013. Inclusion criteria: studies on children and/or youth with CP, interventional/observational studies published in English. Generic measures addressing pain were retrieved. All pediatric pain specific measures were also included.

Construct of the measures were linked to the ICF by two trained professionals.

Results: Overall, 80 measures were identified of which only 18% contained a pain-related domain.

Considerable variability was found in the degree to which their content represented the ICF components. Primarily, measures covered the ICF components of body functions (60%). Few measures covered the components of activities and participation (20%) and environmental factors (2%). Sensation of pain, pain intensity and pain location were the most frequent areas represented by the measures.

Conclusions: This study describes, for the first time, the content of all pain-related measures used in studies with children and youth with CP using a common framework, namely the ICF. Our findings show that the majority of the pediatric pain-related measures address pain intensity and pain location as opposed to functional impact of pain in everyday activities. Using a common framework allows comparisons across measures and help professionals seeking pain measures to meet their research and clinical needs.

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Poster Session Nine

POSTDOCTORAL FELLOW, SUBSPECIALTY RESIDENT OR FELLOW Moderator: KS Joseph Participants: Maria Aristizabal Anita Coté Jenny Fairthorne Saied Samiedaluie Lana Shaiba Folefac Aminkeng

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Board # 61 Maria Aristizabal, Postdoctoral Fellow Supervisor: Michael Kobor & Marla Sokolowski, Medical Genetics

Determine the molecular underpinnings of the effect early life exposures in developmental outcomes in D. melanogaster Maria Aristizabal, Oscar Vasquez, Marla Sokolowski, Michael S Kobor Over a century of research has solidified the formative effect of environmental exposures during childhood, on development and health outcomes in later life. More specifically, adverse early environments are associated with heightened sympathetic and adrenocortical reactivity as well as more complex traits including anxiety, depression, addiction, and antisocial behavior. Given the strong evidence, spanning many different early life adversity exposures, social contexts, and organisms, the next question is what are the biological mechanisms by which environmental signals act during key stages in development to shape neural activity? In D. melanogaster populations are made up of flies with there are two styles of foraging behavior: rovers and sitter. Rovers venture further while foraging for food, carry the forR allele of the foraging (for) gene, and have high levels of PKG enzyme (encoded by for) activity. In contrast, sitters move less, carry the forS allele and have lower PKG enzyme activity. Interestingly, early life nutritional deprivation increases exploratory behaviors in sitter flies but not rover flies providing a well-established paradigm to study how early life adversity shapes behavior. The importance of the for gene in food related behavior and development has been demonstrated in a number different species, including mice, making it a key player in the network by which early life experiences produce lasting behavioral effects later in life. Despite its importance, the function and regulation of PKG, encoded by the for gene, is largely unknown, thus to understand how for contributes to development and behavior we first need to map the molecular pathways it participates in. My project will use high throughput mass spectrometry based technologies to identify protein partners and substrates of PKG.

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Board # 62 Anita Coté, Postdoctoral Fellow Supervisor: Kevin Harris, Pediatrics

Left ventricular mechanics and exercise capacity in clinically stable pediatric heart transplant recipients Anita T Coté, Shreya Moodley, Astrid M De Souza, Terri Zadorsky, James E Potts, Thomas W Rowland, George GS Sandor, Kevin C Harris Background: Both exercise capacity and left ventricular (LV) function have been reported to be suboptimal in children who have undergone heart transplantation (HTx) compared to their peers.

Ventricular twist is important for optimal systolic and diastolic function. However, the nature of LV twist in pediatric HTx has not been investigated. The objective of this study was to assess LV mechanics at rest and during exercise in children who have undergone HTx and determine the relationship with exercise capacity.

Methods: Hemodynamics and measures of cardiac function were assessed in 28 children (n=14 HTx free from rejection, n=14 Controls; Age = 12.6 ± 2.2 years). Speckle-tracking echocardiography was used to assess peak twist, twist and untwist rates, at rest and during semi-supine cycle exercise.

Independent t-tests were used to assess group differences in baseline hemodynamics and exercise capacity. Repeated-measures ANOVA was used to assess interactions and main effects for LV mechanics over time (rest to peak exercise) by group (HTx versus Controls). Linear regression analysis was used to assess the relationship between measures of exercise capacity and LV mechanics.

RESULTS: Children with HTx displayed reduced baseline stroke volume and cardiac indices (SVI, CI), twist rate and untwist rate (all p<0.05). Work (1185 ± 407 versus 740 ± 249 joules) and VO2 at peak exercise (36.2 ± 8.8 versus 27.7 ± 7.0 ml/kg/min) were higher in Controls than HTx (p=0.002 and p=0.013, respectively). LV twist increased during exercise in all children; however, was lower in HTx than Controls independent of time (rest to exercise: 14 ± 4° to 19 ± 6° in HTx versus 17 ± 6° to 25 ± 4° in Controls; p<0.001), as was twist rate (rest to exercise: 134 ± 21 to 187 ± 66°/s in HTx versus 234 ± 63 to 358 ± 105°/s in Controls; p<0.001). An interaction was found for systolic rotation rate at the base, where Controls increased to a greater extent during exercise than HTx (p=0.02). Peak VO2 was associated with change in LV twist and work (r2 = 0.84, p<0.001).

Conclusion: LV twist is reduced in pediatric HTx in the absence of rejection both at rest and during exercise and may contribute to the reduced exercise capacity displayed during exercise in these children.

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Board # 63 Jenny Fairthorne, Postdoctoral Fellow Supervisor: Tim Oberlander, Pediatrics

Early mortality from external causes in Aboriginal mothers Jenny Fairthorne, Roz Walker, Nick de Klerk, Carrington Shepherd Background: Maternal loss can have a deep-rooted impact on families. Whilst a disproportionate number of Aboriginal women die from potentially preventable causes, no research has investigated mortality in Aboriginal mothers. We aimed to examine the elevated mortality risk in Aboriginal mothers with a focus on external causes.

Methods: We linked data from four state administrative datasets to identify all women who had a child from 1983-2010 in Western Australia and ascertained their Aboriginality, socio-demographic details, and their dates and causes of death prior to 2011. Comparing Aboriginal mothers with other mothers, we estimated the hazard ratios (HRs) for death by any external cause and each of the subcategories of accident, suicide, and homicide, and the corresponding age of their youngest child.

Results: Compared to non-Aboriginal mothers and after adjustment for parity, socio-economic status and remoteness, Aboriginal mothers were more likely to die from accidents [HR=6.43(95% CI: 4.9, 8.4)], suicide [HR=3.46(95% CI: 2.2, 5.4)], homicide [HR=17.46(95% CI: 10.4, 29.2)] or any external cause [HR=6.61(95% CI: 5.4, 8.1)]. For mothers experiencing death, the median age of their youngest child was 4.8 years.

Conclusion: During the study period, Aboriginal mothers were much more likely to die than other mothers and they usually left more and younger children. These increased rates were only partly explained by socio-demographic circumstances. Further research is required to examine the risk factors associated with these potentially preventable deaths and to enable the development of informed health promotion to increase the life chances of Aboriginal mothers and their children.

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Board # 64 Saied Samiedaluie, Postdoctoral Fellow Supervisor: Wendy Norman, Family Practice

The SMART Program: Costs and health outcomes associated with provision of cost-free highly effective contraception at time of abortion Saied Samiedaluie, Wendy V Norman, Rollin Brant, Janusz Kaczorowski, Stirling Bryan Objective: Recurrent unintended pregnancy is common in Canada: 40% of women seeking abortion have had a prior abortion. Free contraception during abortion services could mitigate these high rates.

Methods: We enrolled 1031 women in two post-abortion contraception RCTs recruiting at all surgical abortion clinics in BC, May 2010- September 2012. Participants wished to avoid a subsequent pregnancy for at least one year, consented to use administrative data on subsequent outcomes. We analyzed health system costs and outcomes within two years following an index abortion by cohorts of contraceptive method chosen at abortion, when available free. Using Markov modelling we projected system level outcomes and costs for health policy options.

Results: Within two years of index abortion, among each hundred women using the method, those who did not use LARC or hormonal contraceptive methods had 48.2 (95%CI 37.2-59.1) pregnancy outcomes, those using short acting hormonal methods: 39.0 (CI 27.8-50.2), copper IUD 13.5 (CI 10.0-17.1), and LNG-IUS-20mg: 5.8 (95% CI 2.8-8.9). Modelling indicated BC could save 24.1+/0.03% in health system costs and incur 52% fewer subsequent pregnancies within two years following each index abortion, if all women seeking abortion were offered free LARC or hormonal contraceptive methods.

Conclusion: Provision of cost-free highly effective contraception at the time of abortion is a costsaving measure from the health system perspective, and is associated with significant improvement in pregnancy prevention.

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Board # 65 Lana Shaiba, Resident Supervisor: Alfonso Solimano, Pediatrics

RSV prophylaxis for hemodynamically significant congetal heart disease with four palivizumab seasonal doses; Three years of success in British Columbia Lana Shaiba, Jennifer Claydon, Cheryl Christopherson, Derek Human, Alfonso Solimano Background: Infants and young children with hemodynamically significant congenital heart disease (CHD) are at increased risk of hospitalization and mortality from infection from respiratory syncytial virus (RSV) in the first 2 years of life. Most jurisdictions recommend five palivizumab (PVZ) doses for infants with congenital heart disease. Based on pharmacokinetic evidence, the BC RSV Immunoprophylaxis Program has provided four monthly doses per season plus one post-pump dose after surgery since the 201213 RSV season. The interval between the first and second dose is 21 to 28 days, and for subsequent scheduled doses of 28 to 35 days.

Objective: To report on RSV admission rates in British Columbia, over 3 seasons, starting in 2012-13 to 2014-15, for the complete cumulative cohort of CHD patients who are managed with an intention to treat immunoprophylaxis protocol of four-doses plus one post-pump dose after cardiac surgery.

Design/Methods: Outcomes were ascertained from the discharge abstract database of all health authorities in BC. In addition, follow-up was conducted at each of the local RSV Immunoprophylaxis clinics.

RSV admissions were analyzed using pre-defined categories: 1) “drug failure” (during scheduled PVZ course), 2) “non-compliant” (during interdose interval >35 days, or if missed doses), and 3) “schedule failure” (>35 days after last dose).

Results: There were 323 CHD infants enrolled in the BC RSV Immunoprophylaxis program during the 3 year period. Of these, 45 (13.7%) had surgery during the RSV season, and 35 (11%) of the cohort were given extra doses (2 received 6, and 30 received 5 seasonal doses). Of 323, 52 infants were hospitalized for upper or lower respiratory tract infection; 20 infants had a confirmed RSV-positive or RSV-unknown test. Of the 20 infants 3 were “non-compliant”, 11 were for “drug failure”, and 1 was for “schedule failure”. The overall drug failure rate of 11/323 was 3.4%, and the schedule failure rate of 1/323 was 0.31%.

Conclusions: During a five-month RSV season, a four-dose plus post-pump dose schedule of palivizumab is effective for prevention of RSV hospital admission in high risk infants with congenital heart disease.

Amongst RSV Program infants with CHD who receive PVZ, the most common cause for hospital admission due to respiratory tract infection during the RSV season is infection due to other viruses.

Strong emphasis on patient education and health promotion is essential for the prevention of admissions with respiratory tract infection

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Board # 66 Folefac Aminkeng, Postdoctoral Fellow Supervisor: Michael Hayden, Medical Genetics

Pharmacogenomic prediction of anthracycline-induced cardiotoxicity Folefac Aminkeng, Amit P. Bhavsar, Shahrad R. Rassekh, Michael J. Rieder, Jessica Stortz, Francois Dionne, Gabriella Groeneweg, Michael R. Hayden, Bruce C. Carleton, Colin J.D. Ross, and The Canadian Pharmacogenomics Network for Drug Safety Consortium Background/Rationale: Cancer is a leading cause of morbidity and mortality. Over 14.1 million people are diagnosed every year world-wide and it accounts for approximately 15% of all deaths. Anthracyclines are used to treat over 70% of childhood and 50-90% of adult breast cancer patients each year, and have significantly contributed to the improved 5-year survival rates to over 80%. However, their use is limited by cardiac toxicity and congestive heart failure in 57% and 20% of treated patients, respectively.

Uncovering the genetics and pathophysiology of anthracycline-induced cardiotoxicity (ACT) will inform treatment decisions and future drug development.

Methods: Patients were recruited and clinically characterized by the Canadian Pharmacogenomics Network for Drug Safety.

Results: Pharmacogenomic Discovery: We recently published the first GWAS (740 000 SNPs) of ACT and discovered a new gene (RARG) and a new variant (rs2229774, p.Ser427Leu) in children (P = 5.9 × 10−8, OR (95% CI) = 4.7 (2.7–8.3)). We showed that RARG transcriptionally regulated Top2b expression, an activity that is impaired by the rs2229774 variation, thereby providing new insights into the pathophysiology of ACT (Aminkeng F et al. Nature Genetics. 2015 Sep; 47(9):1079-84). We are analyzing the results of another GWAS (1.7 million SNPs) of ACT in 402 adult breast cancer patients. Preliminary results suggest a role for RARG rs2229774 in ACT in adult breast cancer patients (Aminkeng F et al, Manuscript in preparation). We have shown in a separate study that pharmacogenomic testing improves ACT prediction beyond currently implemented clinical risk factors and can inform treatment decisions (Aminkeng F et al, Manuscript in preparation).

Implementation: We developed comprehensive, evidence-based, clinical practice guidelines for ACT pharmacogenomic screening (Aminkeng F et al. Br J Clin Pharmacol. 2016 May 16. doi: 10.1111/ bcp.13008). We conducted a comprehensive health economic evaluation to examine the costeffectiveness of ACT pharmacogenomic testing and shown that pharmacogenomics screening reduces morbidity and mortality and saves cost (Dionne F, Aminkeng F et al, Manuscript in preparation). We are currently implementing point-of-care genetic testing to enhance treatment decisions and 150 childhood cancer patients have been screened in British Columbia (Manuscript in preparation).

Conclusion: Pharmacogenomic prediction of anthracycline-induced cardiotoxicity informs oncology treatment decisions and is cost effective.

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