Interplay Between Microplastic Exposure and Age-related Cognitive Decline

Lauren Gaspar, Sydney Bartman, Giuseppe Coppotelli1, Jaime M. Ross

As the global population continues to rise, so too has the consumption of material goods. One of the most common commodities on the market in recent decades is plastics, with their global production reaching 460 million tons in 2019. Despite the societal advancements plastics have allowed, the mismanagement of plastic waste has become a pressing global issue, especially the leakage of microplastics.Microplastics (plastic particles <5mm in size) have been shown to induce health issues such as oxidative stress, inflammation, and decreased cell viability in marine organisms. Current research suggests that these microplastics may be transported throughout the environment, however research into their health effects, especially in mammals, is still limited.

This has led our group to explore the biological and cognitive consequences of microplastics exposure in a rodent model. Following a three week exposure to water treated with fluorescentlylabeled pristine polystyrene beads, C57/BL6J mice were assessed using behavioral assays such as open field, followed by tissue analyses such as Western Blot, qPCR, and immunohistochemistry. Data from these assays suggests that short term exposure to microplastics induces both behavioral changes and alterations to immune markers in liver and brain tissues. Additionally, we noted that these changes seem to differ depending on age, indicating a possible age-dependent effect. Furthermore, preliminary studies in a humanized APOE3/4 knock-in mouse model, which may be used to study genetic predisposition to Alzheimer’s disease (AD), suggest that microplastics may be exasperating genetic risk factors of AD in a possibly sex-dependent manner. These findings suggest the need for further research to better understand the mechanisms by which microplastics may induce physiological and cognitive changes.

Characterization of Antimicrobial Membrane Vesicles from Pseudoalteromonas piscicida JC3

Ololade Gbadebo, Arvie Grace Masibag, Josiah Morrison, Matthew Bertin, David Rowley

Pseudoalteromonas piscicida JC3 is a marine bacterial strain with the capacity to produce a large number of membrane vesicles (MVs) as well as antibacterial specialized metabolites. The strain has also been suggested to prevent infection of a deadly pathogen Vibrio parahaemolyticus in shrimps. The mechanism of this probiotic activity is however not completely understood. In this study, we report that JC3 produces a large amount of MVs which may mediate its probiotic effect against V. parahaemolyticus. The production of the MVs involved the membrane filtration of a centrifuged 48 h culture of P. piscicida JC3, and the ultracentrifugation of the resulting filtrate. The MVs size distribution was determined by dynamic light scattering (DLS). They were morphologically characterized by transmission electron microscopy (TEM) and assayed for antimicrobial activity against V. parahaemolyticus PSU5579 and Staphylococcus aureus using the agar spot plate method. The protein and lipid concentrations were determined by Bicinchoninic acid (BCA) protein assay and Stewart assay respectively. The methanolic extract of the MVs was analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and dereplicated using MS/MS data work-up computer tools. The DLS measured an average diameter of 188.3 nm. The TEM revealed the spherical shape of the vesicles and showed that the MVs had only one membrane, making them outer membrane vesicles. Protein and lipid concentrations of the MVs suspension were 235 ± 6 mg/mL and 741.2 ± 17 µg/mL respectively. The antimicrobial assay done in replicates showed a clear zone of inhibition around the spot the MV suspension was dropped in the models tested. The metabolomic profiling of the membrane vesicles revealed the presence of alterochromides in the cargo of these vesicles. These findings suggest that MVs may contribute to the probiotic activity of P. piscicida JC3 in shrimp aquaculture, and also have potential as sources of antimicrobial compounds.

Impact of Nebulization on the Physicochemical Properties of Polymeric Nanoparticles for Pulmonary Drug Delivery Applications

Andrea Gonsalves, Jyothi U. Menon

Lung cancer, one of the leading causes of cancer-related mortalities worldwide is usually diagnosed at an advanced stage, thus necessitating rigorous and effective treatment upon diagnosis. Inhalable nanoparticle formulations facilitate pulmonary delivery of therapeutics in a site-specific and sustained manner. Polymeric nanoparticles (NPs) are being widely investigated owing to their biodegradability, biocompatibility and sustained drug release characteristics at a rate corresponding to the polymer degradation rate. Currently, there is great emphasis on developing multiple polymer or lipid layers incorporated within a single system to improve the distribution and half-life of the formulations, and for combination therapy. However, there are limited studies evaluating the physicochemical properties of these single polymer and multipolymer/lipid formulations post-nebulization. Previously, we demonstrated that polymeric NPs coated with the commercial lung surfactant (LS) Infasurf® can evade phagocytosis by alveolar macrophages in vitro. The present work focuses on evaluating physicochemical properties and in vitro therapeutic efficacy of the LS coated poly lactic-co-glycolic acid (PLGA) NPs after passing through a commercial nebulizer Aeroneb®. Particle size, ζ potential and polydispersity index (PDI) of the NPs were found to be 140.6 ± 3.9 nm, -33.0 ± 1.6 mV and 0.298 ± 0.04 respectively pre-nebulization and 142.1 ± 10.81 nm, -31.4 ± 2.9 mV and 0.261 ± 0.01 respectively postnebulization. FTIR analysis and Stewart’s assay confirmed the retention of the LS layer postnebulization. The nebulization efficiency, nebulization time and fluid output rate of the commercial nebulizer Aeroneb® were determined to be 89.03 ± 3.0 %, 420 ± 57 secs and 261.99 ± 45.1 respectively. The drug release study demonstrated an initial burst release followed by a sustained release in PBS at 37°C. Overall, nebulization did not significantly comprise the physico-chemical properties as well as therapeutic efficacy of the drug loaded NPs.

Nuclear Pore Complex Injury and Transcription Alterations Drive Pathology in ALS/FTD

C9ORF72 Mutant iPSC Derived Cortical Neurons

Michelle Gregoire, Livi Donatelli, Alex Burns, Serena Santangelo, Riccardo Sirtori, Claudia Fallini

Nuclear pore complexes (NPC) are the gateway for RNAs and proteins to shuttle between the nucleus and cytoplasm. NPC impairment is often associated with alterations to the nuclear lamina and membrane, as well as to protein mislocalization due to compromised nucleocytoplasmic transport. These phenotypes are consistent with cellular pathologies seen in neurons from patients with the fatal neurodegenerative disease ALS/FTD (Amyotrophic lateral sclerosis/frontotemporal dementia). Thus, we hypothesized that NPC injury can alter activation of transcriptional pathways in ALS/FTD neurons, particularly following stimulatory signals. We found that induced pluripotent stem cell (iPSC)-derived cortical neurons carrying mutations in the C9ORF72 (C9) gene display NPC impairment, altered nuclear membrane morphology, and increased chromatin compaction in an age-dependent manner. However, we found early impairment in the activation of a critical pathway in neuronal health and survival, CREB, in C9 mutant neurons through immunofluorescence and high throughput RNA sequencing assays. Altogether, this data points to the role of not only NPC and nuclear defects, but also of early transcriptional alterations in C9 mutant cells as key and early drivers of pathology.