NeURoscience | Vol 16 | 2023

NE UR OSCIENCE

University of Rochester | Ernest J. Del Monte Institute for Neuroscience Vol. 16 - 2023

Wiggles & Wings:

The systems transforming neuroscience

PhD

FROM THE DIRECTOR’S DESK

To begin by saying this new year has started off well is very much an understatement. A major accomplishment out of the Nedergaard Lab has us all looking at the brain differently—they found a previously undiscovered piece of brain anatomy that you will read about more in this issue.

The discovery of SLYM (a thin membrane that encapsulates the brain) gives all neuroscientists a new insight into how the brain’s defense and immune systems work. It will, inevitably, lead to a better understanding of diseases like multiple sclerosis and Alzheimer’s, and how these neurological conditions may be triggered or worsened by abnormalities in SLYM function.

For our cover story, we consider some of the simplest organisms that play a valuable role in our understanding of the brain and human biology. There are a number of labs at the Medical Center using the model systems—C. elegans and Drosophila—to elevate science. In this issue, you’ll hear from more than a half dozen faculty members advancing our understanding of the interaction between neurons and hormones, mitochondria and stroke, the molecular underpinnings

On the cover

From left: Drosophila and C. elegans.

Photos: John Schlia Photography

Monte Institute for Neuroscience Executive Committee

John Foxe, PhD, Chair, Department of Neuroscience

Bradford Berk MD, PhD, Professor of Medicine, Cardiology

Robert Dirksen, PhD, Chair, Department of Pharmacology & Physiology

Diane Dalecki, PhD, Chair, Department of Biomedical Engineering

Jennifer Harvey, MD, Chair, Department of Imaging Sciences

Robert Holloway, MD, MPH, Chair, Department of Neurology

of Alzheimer’s, and how methyl mercury impacts neurodevelopment, to name a few.

I am grateful to be able to share the work of legendary Dr. Peter Shrager with you in this issue. He chatted with us about his incredible career that continues today, more than 50 years after he arrived in Rochester. He was an electrical engineer whose interest in biomedical engineering led him to navigate the emerging field, that we know today, as Neuroscience.

We had a wonderful trip to sunny California for the Society for Neuroscience conference. Thank you to everyone who joined us at Sally’s Fish House. It was rejuvenating to see so many familiar faces and reunite, reconnect, and even meet for the first time.

What is on the horizon in 2023 is exhilarating. We should all feel challenged and motivated to be ever better in our labs, to each other, and to ourselves.

In Science, John J. Foxe, PhD

Paige Lawrence, PhD, Chair, Department of Environmental Medicine

Hochang (Ben) Lee, MD, Chair, Department of Psychiatry

Shawn Newlands, MD, PhD, MBA, Chair, Department of Otolaryngology

Webster Pilcher, MD, PhD, Chair, Department of Neurosurgery

Steven Silverstein, PhD, Professor, Department of Psychiatry

Duje Tadin, PhD, Chair, Department of Brain & Cognitive Sciences

NEUROSCIENCE

Editor/Writer

Kelsie Smith Hayduk

Kelsie_Smith-Hayduk@ urmc.rochester.edu

Contributors

Emily Gillette Mark Michaud Kelly Webster

Feature Photography John Schlia Photography Designer Beth Carr

John J. Foxe,

Kilian J. and Caroline F. Schmitt Chair in Neuroscience Director, Ernest J. Del Monte Institute for Neuroscience

Professor & Chair, Department of Neuroscience

Del

Newly discovered anatomy shields and monitors brain

From the complexity of neural networks to basic biological functions and structures, the human brain only reluctantly reveals its secrets. Advances in neuro-imaging and molecular biology have only recently enabled scientists to study the living brain at a level of detail not previously achievable, unlocking many of its mysteries. The latest discovery, described in the journal Science, is a previously unknown component of brain anatomy that acts as both a protective barrier and platform from which immune cells monitor the brain for infection and inflammation.

The new study comes from the labs of Maiken Nedergaard, MD, co-director of the Center for Translational Neuromedicine at the University of Rochester and the University of Copenhagen, and Kjeld Møllgård, MD, a professor of neuroanatomy at the University of Copenhagen. “The discovery of a new anatomic structure that segregates and helps control the flow of cerebrospinal fluid (CSF) in and around the brain now provides us a much greater appreciation of the sophisticated role that CSF plays not only in transporting and removing waste from

Central nervous system immune cells (indicated here expressing CD45) use SLYM as a platform close to the brain's surface to monitor cerebrospinal fluid for signs of infection and inflammation.

Newly discovered membrane in the brain called SLYM is a thin but tight barrier that appears to separate "clean" and "dirty" CSF and harbors immune cells.

the brain but also in supporting its immune defenses,” said Nedergaard.

The new membrane is very thin and delicate, consisting of only a few cells in thickness. Yet Subarachnoidal LYmphatic-like Membrane, or SLYM, is a tight barrier, allowing only very small molecules to transit and it also seems to separate “clean” and “dirty” CSF. This last observation hints at the likely role played by SLYM in the glymphatic system, which requires a controlled flow and exchange of CSF, allowing the influx of fresh CSF while flushing the toxic proteins associated with Alzheimer’s and other neurological diseases from the central nervous system. This discovery will help researchers more precisely understand the mechanics of the glymphatic system, which was the subject of a recent $13 million grant from the National Institutes of Health’s BRAIN Initiative to the Center for Translational Neuromedicine at the University of Rochester.

The SLYM also appears important to the brain’s defenses. The central nervous system maintains its own native population of immune cells, and the membrane’s integrity prevents outside immune cells from entering. In addition, the membrane appears to host its own population of central nervous system immune cells that use SLYM as an observation point close to the surface of the brain from which to scan passing CSF for signs of infection or inflammation.

Children with HIV at greater risk for impaired neurological development

Research in Zambia finds that children infected with HIV are significantly more likely to do worse in neurological assessments despite having well-controlled HIV disease, suggesting that they may struggle with cognitive and mental health issues. However, the research also indicates that early intervention—in the form of better nutrition and antiretroviral therapies—may help close the gap. The study is the most recent example of a decades-long collaboration

the University Teaching Hospital (UTH) in Lusaka, Zambia. Together, they study neurological problems associated with infectious diseases like HIV and malaria, which remain major public health problems in sub-Saharan Africa.

Solar panels for cells: Light-activated proton pumps generate cellular energy, extend life

, associate professor of Anesthesiology & Perioperative Medicine and Pharmacology & Physiology at the University of Rochester Medical Center, found that simply boosting metabolism using light-powered mitochondria gave laboratory worms longer, healthier lives. These findings and new research tools pave the way for researchers to further study mitochondria,

Researchers reveal how trauma changes the brain

Exposure to trauma can be lifechanging—and researchers are learning more about how traumatic events may physically change our brains. These changes are not happening because of physical injury, rather our brain appears to rewire itself after traumatic experiences. Understanding the mechanisms involved in these changes and how the brain learns about an environment and predicts threats and safety is a focus of the ZVR Lab at the Del Monte Institute for Neuroscience at the University of Rochester, which is led by assistant professor Benjamin Suarez-Jimenez, PhD

The findings, published in Communications Biology,

identified changes in the salience network—a mechanism in the brain used for learning and survival—in people exposed to trauma (with and without psychopathologies, including PTSD, depression, and anxiety). Using fMRI, the researchers recorded activity in the brains of participants as they looked at different-sized circles—only one size was associated with a small shock (or threat). Along with the changes in the salience network, researchers found another difference— this one within the trauma-exposed resilient group. They found the brains of people exposed to trauma without psychopathologies were compensating for changes in their brain processes by engaging the executive control network— one of the dominant networks of the brain.

New research in the journal Nature Aging takes a page from the field of renewable energy and shows that genetically engineered mitochondria can convert light energy into chemical energy that cells can use to ultimately extend the life of the roundworm C. elegans. While the prospect of sunlight-charged cells in humans is more science-fiction than science, the findings shed light on important mechanisms in the aging process.

identify new ways to treat age-related diseases, and find ways to support a healthier aging process.

The model systems transforming neuroscience

WIGGLES&WINGS:

There is no better sign that the banana on your counter is ripe than the buzz of a fruit fly, and if that banana were outside, it would likely also have many microscopic worms enjoying the bacteria found on the rotting fruit. They can be creepy. They can be crawly. But C. elegans and Drosophila, or soil nematodes (roundworms) and fruit flies, are actually really helpful in deepening our understanding of the mechanisms that regulate brain structure, function, and aging. These genetic model organisms are truly invaluable to the field of neuroscience. Many of the discoveries made using C. elegans and Drosophila apply throughout the animal kingdom, and this research has led to a broader understanding of human biology. Five C. elegans researchers have won the Nobel Prize, and six Drosophila researchers have also been bestowed the highest honor in science.

KNOWING EACH NEURON

“The fact that the C. elegans’ neuroanatomy is simple is one of the original reasons it was chosen as a model system,” explained Douglas Portman, PhD, professor of Biomedical Genetics, Neuroscience, and Biology at the University of Rochester Medical Center. Scientists have identified all 302 of the adult worm’s neurons. “But C. elegans does have relatively complex behaviors. It can make decisions and react to encountering things like food, a potential predator, or even touching something new. It also has plasticity and can learn.” These behaviors are where neuroscientists come in, they provide researchers the opportunity to understand how genes guide the development and function of the nervous system.

Portman began working with C. elegans during his postdoc under Scott Emmons, PhD, of the Albert Einstein College of Medicine, who trained under Sydney Brenner, PhD, the scientist who established C. elegans as a genetic model system. Portman’s current research has found that biological sex can act to regulate the way that neurons work. His work published in Current Biology found male brains—at least in C. elegans—will suppress the ability to locate food

to focus on finding a mate. “The tractability of the C. elegans system has allowed us to understand pretty deeply how that works at the level of changes in gene expression and neuronal properties,” Portman said. “The chromosomal sex of the nervous system gives the primary cue that tells neurons if they should be in a male or hermaphrodite state. One important insight from our work is that it is not a fixed static binary decision but a flexible one. It challenges the way we think about sex as a biological variable.”

It is also an important consideration in human health and disease as scientific discoveries lead to a better understanding of the interactions between genes, hormones, and neurons, the genetic makeup on a neuron could influence its response to hormonal signals.

THE AGING OLD QUESTION

With a three-week lifespan, C. elegans can expedite experiments. Associate professor of Anesthesiology & Perioperative Medicine, and Pharmacology & Physiology Andrew Wojtovich, PhD, finds these to be a beneficial model system for his research around aging and stroke. “C. elegans tell us more about the contextual nature of things. Working with a simple organism allows us to focus on molecular questions rather than technical ones. I like to say that we study the engine while a car is in motion, not while it is up on cinderblocks.”

He uses the model system to investigate the different classes of alr-1/ ARX mutations and how these cause specific syndromes like epilepsy. By disrupting specific subsets of alr-1/ARX-regulated gene networks Diaz-Balzac is aiming to understand how the gene affects the function of neural circuits in the brain.

Endocrinology fellow Carlos Diaz-Balzac, MD, PhD, warms a tool in a flame while working with C. elegans in the Portman Lab.

Doug Portman, PhD.

Postdoctoral fellow Andrew Peter Bischer, PhD (front) works in hypoxic chamber with Andrew Wojtovich, PhD.

John Onukwufor, PhD, research assistant professor of Pharmacology & Physiology, works with C. elegans at a microscope in the Wojtovich lab. His research aims to understand the role of mitochondrial iron dysregulation in driving metabolic disruption and Alzheimer’s disease. He also uses both pharmacologic and genetic means, including biosensors, to monitor in vivo changes that occur during mitochondrial iron dysregulation in Alzheimer’s disease.

The Wojtovich Lab studies mitochondrial physiology in the context of hypoxic biology or stroke. In an effort to control the mitochondria’s ability to make energy, they discovered how to create the opposite effect. The lab developed a tool that uses light to recharge the mitochondria, an application that Wojtovich believes has endless potential. “Mitochondrial dysfunction is typical in many neurological diseases. Take, for example, Alzheimer’s disease, which is characterized by impaired energy production and biomarkers of mitochondrial dysfunction. However, the cause-and-effect relationship between mitochondria and pathology progression is unclear. I see our work and genetic tools giving us a better understanding of these disease pathways.”

C. elegans aging is central to work taking place in the Nehrke Lab located in the Nephrology Division in the department of Medicine at the Medical Center. “C. elegans is an unbelievable genetic resource,” professor Keith Nehrke, PhD, said. “We can do things very quickly and effectively, while limiting potential confounds and generating binary (yes or no) answers by asking these questions in a model system. In our case, aging is the main risk factor in most neurodegenerative diseases, and that takes only weeks in C. elegans rather than years.”

More than a decade ago, Nehrke and Anesthesiology & Perioperative Medicine professor Gail Johnson, PhD, began collaborating using C. elegans to ask questions about the underlying mechanisms of Alzheimer’s disease. They are studying how changes to tau—a protein that helps nerve cells maintain this structure and function—impact mitochondrial health and neuronal aging. An impairment

in tau function is associated with the development of neurodegenerative diseases like Alzheimer’s. Using a C. elegans model, they are able to leverage the molecular underpinnings of Alzheimer’s together with recent genomeediting technologies such as CRISPR/Cas9 to define the precise mechanism through which toxic tau compromises

Keith Nehrke, PhD, assists graduate student Trae Carroll with fluorescent imaging.

From left: Postdoctoral fellow Michael Isei, PhD, and Gail Johnson, PhD.

mitochondrial function and accelerates neuronal aging. The labs’ most recent data indicates that worms expressing even low levels of disease-associated tau show a significant increase in age-dependent neurodegeneration and a suppression of stress-induced mitophagy, a mechanism for recycling damaged mitochondria that is important for maintaining a pool of healthy organelles.

Along with providing insight into underlying mechanisms of disease, the Nehrke and Johnson labs also use the C. elegans model to study a drug’s impact on behavior or neurodegenerative output. Because the molecular targets of pharmaceuticals are often the same in the worms as they are in people, the labs can use pharmacogenetic approaches

to see what molecules the drugs interact with to convey a response.

“We know each neuron in C. elegans and working with a small population of neurons gives us better insight into what we are looking at. It is a better first pass at testing a hypothesis because they can be genetically manipulated rapidly,” Johnson said. “We can run experiments in weeks rather than years, like in mice models, and get some real data that tells us where to go next.”

And next—maybe one step up on the model systems chain—from the 302 neurons in C. elegans to ~100,000 neurons in Drosophila melanogaster, or the fruit fly.

WHAT’S ALL THE BUZZ?

“Drosophila have very complex behaviors, similar to larger animals. Flies are trainable in a Pavlovian behavior,” said Matthew Rand, PhD, associate professor of Environmental Medicine. “For example, you can train a fruit fly to go towards a light based on a reward of food being there. Some fundamental neurobiological circuits and processes are coded in this tiny little organism.”

Rand’s lab focuses on mercury toxicity, specifically methyl mercury found in fish and how it impacts the nervous system. His current research intersects with neuroscience in the sensitivity of developmental neurobiology. The fruit fly has been a longstanding model organism that has allowed researchers to identify genes

responsible for producing proteins that coordinate building the structure and supporting the functions of our most fundamental tissues and organs. Using this model, his lab has discovered that the developing muscular system is a sensitive target to methyl mercury along with the nervous system.

“It appears that the toxicant attacks a developing organism beyond just a single system, like a neuron or a nervous system, and that there is a higher-level systemic effect that may be attacking muscle and neuron and the communication between the two during development,” Rand said. It begins to allow for the identification of molecular and/or gene candidates. Specifically, the

From left: Matthew Rand, PhD, and graduate student Catherine Beamish.

molecules or genes already known to crossover in neurodevelopment and muscle development. These can be targeted to provide insight into how an altered gene expression in a neuron may affect a muscle that could enhance toxicity, or alternatively compensate for injured neurons.

The 100,000 neurons that make up the Drosophila brain are a drop in the bucket compared to the 86 billion neurons in the human brain. Yet do not underestimate the six-legged, twowinged insects. “It performs a lot of sophisticated behaviors; it can fly, see, smell, taste, touch, hear, and balance,” said Rajnish Bharadwaj, MBBS, PhD, assistant professor of Pathology & Laboratory Medicine and Neuroscience. “The fruit fly is genetically amenable, allowing us to manipulate genes quickly, examine small subsets of neurons, and more clearly examine certain cell biological processes.” The fruit fly’s fundamental biological make-up is similar to humans. It shares 75 percent of genes that cause disease in people.

The Bharadwaj Lab aims to understand the gene involvement in Parkinsonism—a group of neurological disorders that cause movement problems similar to those seen in Parkinson's disease, and neurodegeneration with brain iron accumulation—a rare neurological movement disorder. “We are showing the first evidence that this gene, C19orf12, impacts lipid homeostasis in the brain and other organs,” said Bharadwaj. “We believe understanding more about this gene is important to several neurological disorders. In addition to its known role in the genetic disease NBIA, it has interesting similarities with Parkinson’s disease such as accumulation of the protein synuclein in various parts of the brain.”

NEW LAB TAKES FLIGHT

Gabriella Sterne, PhD, traveled 2,700 miles to begin her assistant faculty position in the Department of Biomedical Genetics at the Medical Center. The collaborative nature of the University and established invertebrate labs attracted the scientist who wrapped up her postdoctoral fellowship at UC Berkeley. “There is this really cool invertebrate community that meets weekly here,” said Sterne. “It is so important to research, it fosters collaboration and breeds new ideas.”

Sterne works with Drosophila to understand how the brain encodes feeding experiences and how it uses those experiences to inform memory formation and make future feeding decisions. “Understanding the relationship between memory and feeding decisions will reveal general and fundamental principles of how neural circuits work,” said Sterne. “I think it will offer more specific insights into how feeding is regulated in animals which has implications for human health, disease, and pest control.”

TINY SCIENTIFIC TITANS

The complex questions these model systems can and have answered transforms our understanding of molecular biology and neuroscience. The physical size of Drosophila and C. elegans and their lifespans allows researchers to usher in more data faster than they can with other animal models. Their simple systems are a mecca for scientific discovery. And their similarities to humans are also helpful—and interesting. Did you know fruit flies can taste many of the same things as humans, including sweet, bitter, salty, and sour? It may be why they hang out in your kitchen.

Gabriella Sterne, PhD.

From left: Research technician Kristen Patten and Rajnish Bharadwaj, PhD.

Peter Shrager, PhD

Peter Shrager, PhD, is a professor of Neuroscience and Pharmacology & Physiology at the University of Rochester Medical Center (URMC). He received his undergraduate degrees in liberal arts and electrical engineering at Columbia, PhD at the University of California, Berkeley, and completed his postdoctoral research in physiology and immunology at Duke University. In 1971, Shrager came to URMC to work in the Department of Physiology. His research interest is in axonal conduction, particularly ion channel structure, function, and localization—with a special focus on the interaction between neurons and glial cells resulting in myelination.

What led you to neuroscience?

As an undergraduate, while I studied electrical engineering, I found my interest shifting to biomedical research. At UC Berkeley, I switched from engineering to the biophysics program. My research focused on conduction in giant axons of an invertebrate, the crayfish. In those days, we knew that voltage-dependent ion channels were at the root of excitability, but we had no idea how they were built or how they worked. I combined protein physical chemistry and electrophysiology to do some very early investigations in this area.

What brought you to the University of Rochester?

approaches. In those days, we had to design and build the equipment ourselves. My UR colleague, Clay Armstrong, PhD, and I were among the first electrophysiologists to utilize computers to run experiments and analyze data in neuroscience.

How has your research evolved?

For the first 20 years at UR, my research focused on structure-function in ion channels. I then became interested in ion channel localization. We used novel approaches in electrophysiology to probe channel distribution, then turned to optical recording techniques, making it possible to follow signals propagating along single axons. It led us to an analysis of conduction in pathological situations, such as segmental demyelination, as it occurs in multiple sclerosis and Guillain-Barre syndrome. We have since investigated many associated phenomena in both normal development and pathological situations and have expanded our interests to several other ion channel types. Today, our research is largely collaborative. We are working with James Salzer, MD, PhD, at NYU, to investigate a key transcription factor necessary for myelination and the clinical conditions that result from changes in its expression. I also work with several people at UR; it’s an atmosphere I have found to be conducive to collaboration.

Your reputation with students precedes you. How do you connect and engage with students?

Peter Shrager, PhD (right), with former students, Matthew Rasband, PhD (left), professor of Neuroscience, Baylor College of Medicine; Ekaterina (Katya) K. Noyes, PhD (center), professor and director, Division of Health Services Policy and Practice, University at Buffalo.

In 1971, I was recruited to the UR by Paul Horowicz, PhD, a muscle electrophysiologist who had just become chair of Physiology here. Horowicz rapidly built a team interested in ion channels and related areas, making UR internationally known in the field. The atmosphere was incredibly interactive and supportive and fostered some real innovation. It was an era prior to the cloning of ion channels, but major results came from combinations of electrical and chemical

I have always enjoyed teaching. It has always been in my life; my father was a teacher. When I first came to Rochester, I taught medical and graduate students. Today, I teach graduate students. My approach has always been fundamentally the same. I teach students to analyze cellular phenomena through problem-solving rather than rote memorization. I use this approach because I believe it is the only way to learn how electrical signaling works. I am also responsible for the course Biology of Neurological Disorders, which Robert Joynt, MD, PhD, the founder and former chair of Neurology, and dean of the School of Medicine and Dentistry began. In each session we cover a different neurological disorder or developmental disease state from three angles—clinical, basic pathophysiology, and peer-reviewed research. It is rewarding to see how the experience benefits our students. I find that our students are exceptional in their ability to learn and conduct research in neuroscience.

Johanna Fritzinger STUDENT SPOTLIGHT

Johanna Fritzinger is a fourth-year Neuroscience graduate student at the University of Rochester Medical Center. Fritzinger graduated from Case Western Reserve University with a BS in Electrical Engineering and a minor in Music. Fritzinger is currently working in the lab of Laurel Carney, PhD, studying how complex sounds with timbre, the quality that allows sounds to be distinguished when they are identical in pitch, level, and duration, are represented in the auditory midbrain.

NIH awarded Fritzinger an F31 to investigate how the frequency spectrum of sounds with synthetic or natural timbre is expressed in neurons of the auditory midbrain. As part of this project, they are also improving a computational model of the auditory midbrain to better predict neuronal responses to timbre and other complex sounds. This research aims to better inform novel signal-processing strategies to benefit users of cochlear implants and hearing aids. Currently, these devices distort timbre.

“By using a range of musical sounds, we can more fully capture how mechanisms in the auditory system function in everyday life,” Fritzinger said. “I’m working in models with normal hearing to better understand how timbre is encoded in a healthy midbrain. This project has a basic science focus, but if we improve our computational midbrain model it could be applied to different hearing aid applications.”

Fritzinger’s journey to neuroscience was partly serendipitous. Fritzinger was a classically trained pianist interested in electrical engineering. During undergraduate school, they realized they could combine both interests in auditory neuroscience. “When I was interviewing for the graduate school here, I was surprised to learn how many faculty had engineering backgrounds. My undergraduate neuroscience training was limited, but I had the confidence that I would have the support needed to get me where I am today.”

Sally J. States Pilot Fund fuels Alzheimer’s research

Established in 2019, the Sally J. States Pilot Fund in Alzheimer’s Research was made possible by a gift from Sally J. States, a patient inspired to give by the care she and her family received over decades at the University of Rochester Medical Center. “This fund is a small way for us to thank the University community for the connection, care, and support they provided us and that they give to so many in the Rochester community,” said Kathy Burke, States’ daughter.

The States Pilot Fund has advanced two labs led by principal investigators M. Kerry O’Banion, MD, PhD, and Mark Noble, PhD. Both labs have addressed critical areas of Alzheimer’s research over the past three years, including the role that microglia may play in the loss of neuron connections in the brain after radiation and interventions that may correct multiple problems in cell function that occur in Alzheimer’s disease.

“My mother was alert to the burden of Alzheimer’s disease as a public health challenge, both from her own experience and that of my dad’s,” Burke said. “They both wished there were answers and effective treatments, if not for them, for others. My mom especially liked the idea of making a gift toward pilot funding because such grants can be catalytic in the careers of young scientists.”

With the fund’s support, both labs are poised to build off their discoveries, leading to new understanding and potential treatments for the millions afflicted with Alzheimer’s disease.

Johanna Fritzinger

From left: Sally J. States stands with daughter Kathy Burke.

Scan to support Neuroscience research

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