Lab Members

Current lab members

Leire Abalde-Atristain

Leire Abalde-Atristain, Ph.D. abaldeat@ohsu.edu
Postdoctoral Fellow

Born in the beautiful town of San Sebastian in the Basque Country (Northern Spain), Leire received her B.Sc. in Biotechnology from the Autonomous University of Barcelona, and her M.Sc. in Biomedical Research from the Pompeu Fabra University in Barcelona. Sponsored by the Spanish predoctoral La Caixa Fellowship, she then obtained a Ph.D. from the Johns Hopkins University, where she investigated the molecular mechanisms underlying neuron survival and death under the guidance of Ted and Valina Dawson. Leire joined the Freeman lab in late 2019 to pursue her interest in the signals injured neurons send to elicit a response in glia.

Adel Avetisyan

Adel Avetisyan, Ph.D. avetisya@ohsu.edu
Postdoctoral Fellow

Adel completed her Ph.D. at the lab of Professor Adi Salzberg, Rappaport Faculty of Medicine, Technion — Israel Institute of Technology. During her graduate studies she worked on the programmed cell death and cell-fate determination processes that take place during the development of Drosophila chordotonal organs. Adel joined the Freeman lab in 2018 to study the molecular mechanisms underlying axonal degeneration.

Romina Barria

Romina Barria, M.S. barria@ohsu.edu
Senior Research Associate

Romina studied Biochemistry at the University of Chile, earning a B.S degree in 2003 and an M.S. in 2006, exploring the role of the S97N domain of Dlg in synapse development in Drosophila melanogaster. She then joined the laboratory of Dr. Vivian Budnik at UMass Medical School as a research associate, where she assisted in several projects examining synaptic development at the neuromuscular junction in Drosophila. Romina volunteered as a science teacher in India for a few years and later worked as a lab manager in a postharvest lab in Chile. From 2015 to 2017, she studied glia’s role in axon maintenance in the laboratory of Dr. Marc Freeman at UMass Medical School. Romina rejoined the Freeman lab in 2019, after it relocated to the Vollum Institute.

Jiakun Chen, PhD

Jiakun Chen, Ph.D. chenjia@ohsu.edu
Postdoctoral Fellow

Jiakun received his bachelor's and master's degrees in Biochemistry and Molecular Biology from Xiamen University, China. In 2012, he began his graduate studies in the laboratory of Dr. Lilianna Solnica-Krezel at Washington University in St. Louis where he studied early embryogenesis in zebrafish. After receiving his Ph.D., Jiakun joined the Freeman and Monk labs in March 2018. He is interested in astroglial maturation and plasticity during development and in neurological disorders and using both fruit fly and zebrafish models.

Ya-Chen Cheng

Ya-Chen Cheng, M.S. chengy@ohsu.edu
Research Assistant 2

Ya-Chen graduated from National Tainan University in Taiwan with a B.S. in Biology. In 2015, she earned her M.S. in Molecular Medicine from National Taiwan University in Taiwan, studying how the nervous system regulates cardiac tube beating in Drosophila. After graduation, Ya-Chen conducted protein purification and drug assays at the Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes in Taiwan. She joined the Freeman lab as a research assistant in 2018, focusing on screening the suppressors of Nmnat knockdown-induced neuron degeneration.

Megan Corty

Megan Corty, Ph.D. corty@ohsu.edu
Postdoctoral Fellow

Megan is a postdoc originally from sunny Southern California. She received her B.A. in Human Biology from Stanford University before heading east to earn her Ph.D. in Neurobiology from Columbia University, where she studied dendrite morphogenesis in the lab of Wesley Grueber. Megan started her postdoc in the Freeman Lab at UMass Medical School and moved with the lab to its new home at OHSU. Megan's research in the Freeman lab focuses on identifying the cellular and molecular mechanisms controlling glia-axon communication and glial ensheathment of axons.

Jiun-Min (Jimmy) Hsu

Jiun-Min (Jimmy) Hsu, M.S. hsji@ohsu.edu
Graduate Student

Jimmy earned a B.S. in Biomedical Engineering and Environmental Science at National Tsing Hua University in Taiwan. He then spent two years in Dr. Chun-Liang Pan's lab at National Taiwan University, working on tubulin-mediated polarized synaptic vesicle transport. After obtaining his M.S. in 2012 — and one year of military service — he returned to the Pan lab as a research assistant for another two years, studying the mechanism of activity dependent mitochondria fragmentation in C. elegans neurons. In 2015, Jimmy was fortunate to have the opportunity to pursue his Ph.D. degree at UMass Medical School where he joined Marc Freeman's lab, studying the mechanism of dSarm-mediated axon degeneration. He moved with the Freeman lab to the Vollum Institute in 2016.

Taylor Jay

Taylor Jay, Ph.D. jayta@ohsu.edu
Postdoctoral Fellow

Taylor grew up in Kansas and received her B.S. in Brain & Cognitive Science and in Physics from the Massachusetts Institute of Technology. She did her Ph.D. training at Case Western Reserve University, studying microglial function in Alzheimer’s disease and neurodevelopment with Gary Landreth and Bruce Lamb. She began her postdoctoral fellowship in the Freeman lab in 2019, where she is studying the role of glia in synapse development and plasticity.

Amanda Jefferson

Amanda Jefferson, B.S. jefferam@ohsu.edu
Research Assistant 2

Amanda graduated from Portland State University with a B.S. in Biology in 2016. During her undergraduate studies she assisted in the labs of Philip Copenhaver (Department of Cell, Developmental and Cancer Biology, OHSU) and Mike Forte (Vollum Institute). Upon joining the Freeman lab Amanda has assisted in research examining neuron and glia communication during neuronal remodeling.

Yunsik Kang

Yunsik Kang, Ph.D. kangy@ohsu.edu
Postdoctoral Fellow

Yunsik received his Ph.D. in Genetics in 2016 from University of Wisconsin-Madison, studying the genetic control of cell death during Drosophila development. He joined the Freeman Lab in 2016, and his research focuses on identifying mechanisms that eliminate unneeded cells in the brain.

Alexandria Lassetter

Alexandria Lassetter, M.S. lassetta@ohsu.edu
Graduate Student

Alexandria earned her B.S. from the University of California, Davis in 2015. She went on to study mechanisms of familial amyotrophic lateral sclerosis while earning her M.S. in Stem Cell Biology and Regenerative Medicine from the University of Southern California in 2016. Alexandria joined the Freeman lab in 2017 and is currently investigating the role of glia in long-term axon maintenance.

Katy Lehmann

Katy Lehmann, B.S. lehmannk@ohsu.edu
Graduate Student

Katy earned a B.S. in Biology and Health, Science, Society and Policy from Brandeis University in 2016. While at Brandeis she worked in Dr. Avi Rodal’s laboratory to investigate how the regulation of endosomal trafficking in Drosophila hemocytes contributes to systemic immune activation. She then spent two years at the NIH as an IRTA Fellow in Leo Belluscio’s lab defining the role of glia in mouse olfactory system development. Katy joined the Freeman lab in 2019 and is interested in the neuron/glia signaling mechanisms underlying synaptic pruning.

Tzu-Huai (Leo) Lin

Tzu-Huai (Leo) Lin, M.S. litz@ohsu.edu
Graduate Student

Tzu-Huai (Leo) Lin received his B.S. and M.S. in Life Sciences from National Yang Ming University in Taiwan in 2011 and 2013 respectively, where he studied how the Hippo pathway regulates collective cell migration using Drosophila ovary as a model. After a year of experience as a research assistant in Taiwan, he joined the Freeman lab in 2015, embarking on the quest for understanding axonal mitochondrial biology with Gaynor Smith, a former postdoc of the lab and currently a PI at Cardiff University, UK. Leo performed a forward genetic screen to discover new molecules regulating axonal mitochondrial dynamics during his first year in the lab and has been working on one of the hits pulled from the screen since then.

Zhiguo Ma

Zhiguo Ma, Ph.D. mzh@ohsu.edu
Postdoctoral Fellow

Zhiguo earned his B.S. at Anhui Medical University (Anhui, China) in 2005. He then moved to the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences (Beijing, China) where his Ph.D. thesis focused on cholesterol regulated spermatogenesis and neuropeptide trafficking in Drosophila. After graduation in 2011, he joined the Freeman lab (Umass Medical School) and began to explore how astrocyte calcium signaling regulates neural circuits and behavior. In 2016, he relocated to Portland with the Freeman lab where he continues to study astrocyte-neuron, astrocyte-vasculature interactions.

Ernesto Manzo

Ernesto Manzo, Ph.D. manzoe@ohsu.edu
Postdoctoral Fellow

Ernesto received his B.A. in Biology from Swarthmore College where he became fascinated by how genetic alterations cause human disease. In 2010, he was an intern at the Clinic for Special Children, where he studied genetic diseases in the Amish and Mennonite Plain populations under Dr. Erik G. Puffenberger. He received his Ph.D. in Molecular and Cellular Biology from the University of Arizona where he studied metabolic defects implicated in amyotrophic lateral sclerosis (ALS) in the laboratory of Dr. Daniela C. Zarnescu. He is currently interested in how cellular mechanisms control neuronal decay. He uses the fruit fly as a model organism to better understand how neurons survive or degenerate in response to genetic insults. Ernesto is a former HHMI predoctoral Gilliam Fellow with an interest in promoting diversity in higher education.

Danielle Mathieson

Danielle Mathieson, B.S. mathiesd@ohsu.edu
Graduate Student

Danielle earned a B.S. in Neuroscience and Cognitive Science from the University of Arizona in 2017. While there she conducted research in the laboratories of Mary Peterson and Daniela Zarnescu. Danielle joined the Freeman lab in 2018 and is interested in the role of glia in the context of injury and axon degeneration.

Pau Meraner

Paul Meraner, M.D. meraner@ohsu.edu
Senior Research Associate

Paul received an M.D. from the Medical University of Vienna in Vienna, Austria, in 1996, where he also trained as a clinical dermatologist, obtaining board certification in 2005. He then decided to pursue science full time. Coming to the U.S. in 2007, he worked on calcium signaling in the lab of Anjana Rao and Patrick Hogan at Harvard Medical School, Boston, MA, and the La Jolla Institute for Allergy and Immunology in La Jolla, CA. Paul then decided to switch gears from protein biochemistry to systems biology and joined the lab of Abraham Brass at UMass Medical School in Worcester, MA, where he performed CRISPR screens to study virus-host interactions and viral entry mechanisms. The broad applicability of CRISPR technology led to a collaboration with the Freeman lab at UMass, and ultimately to an offer to move out West and join the lab at OHSU. Paul, who always dreamt of working in neuroscience, is currently employing CRISPR screening technology to dissect the SARM1-mediated axon degeneration pathway. Taking advantage of his expertise in biochemisty, he also tries to understand SARM1 signaling at the molecular level.

Amy Sheehan

Amy Sheehan, B.S. sheehana@ohsu.edu
Senior Research Associate

Amy received her B.S. in Biology from Eastern Connecticut State University in 1994. From 1994 to 1999, she was the head research assistant — under the direction of Dr. Petra Ross-Macdonald — on a yeast function genome project in the laboratory of Dr. M. Snyder at Yale University. Amy moved to Eugene, Oregon in 1999. In 2000, she became a research technician III with the Howard Hughes Medical Institute, serving as the head molecular biologist on numerous projects in Dr. Chris Doe's lab at the University of Oregon. From 2004 to 2017, Amy was a research associate II and lab manager in the Freeman lab at the University of Massachusetts Medical School, Worcester, Massachusetts. She continues in her role as the Freeman lab manager here at the Vollum Institute. However, Amy's main job is being the mother of four wonderful kids and running the Freeman household — all with a large glass of wine!

Tobias Stork

Tobias Stork, Ph.D. storkw@ohsu.edu
Research Assistant Professor

Tobias worked on various aspects of glial development and function using Drosophila as a model organism throughout his career. He earned his masters degree and Ph.D. in Biology in the lab of Christian Klämbt at the University of Münster, Germany — analyzing the genetic control of midline glia development and the anatomy and function of the glial blood-brain barrier. In 2007 Tobias joined the Freeman lab to study the genetic control of astrocyte morphogenesis as well as astrocyte function in the Drosophila nervous system.