The Pepper Lab explores the key mechanisms that drive nerve regeneration after injury. Our goal is to identify new cellular and small molecule-based strategies that improve the clinical treatment of nerve injury. Our lab is the scientific arm of the Stanford Facial Nerve Center, a specialized, multidisciplinary treatment center for facial paralysis and related conditions.
Regeneration of nerve tissue and blood supply after nerve injury
Nerve injury, whether the result of trauma or surgical transection in preparation for repair, has long been viewed differently than other soft tissue wounds. However, like all wounds, nerve injury requires a regenerative response that restores the structure and blood supply of the injured tissue.
Using a microsurgical model of facial nerve injury in the mouse that we developed, our research explores the molecular pathways that drive nerve tissue regeneration after injury. We are particularly intrigued by the ways that nerve connective tissue, or mesenchyme, responds to injury. Our prior work has highlighted the role of the Hedgehog pathway in mediating this response to nerve injury.
This image, featured on the cover of Experimental Neurology, shows endoneurial fibroblasts (marked in red) repopulating the injured facial nerve. Our subsequent work has shown that these endoneurial fibroblasts participate in repair of the injured nerve and likely express angiogenic factors that help to restore the blood supply of the nerve.
Improving Nerve Regeneration After Injury
Based on our prior work, we now employ targeted small molecules to modulate key signaling pathways as a means of increasing the rate of recovery after facial nerve transection injury.
Small molecules applied during the time of nerve injury and recovery may hasten the recovery of the nerve. The top image shows a facial nerve two weeks after transection injury, with the mouse treated with a small molecule before and after nerve injury. A mouse treated with vehicle is shown below, also two weeks after facial nerve transection injury
Surgical Innovation at the Stanford Facial Nerve Center
Our scientific discoveries in the lab improve the ways in which we treat our patients. Our work on facial nerve regeneration in the mouse model has informed the development of new microsurgical techniques for the treatment of facial paralysis.
The Dual Nerve Transfer for facial reanimation describes the combination of a masseteric nerve transfer with a simultaneous end-to-side nerve transfer of the proximal facial nerve to the hypoglossal nerve.
Jon-Paul Pepper, MD
Dr. Pepper is the Director of the Stanford Facial Paralysis Center and directs both the scientific and clinical work that is dedicated to improving outcomes after facial nerve injury. He has directed a research lab focused on nerve regeneration since 2013 and moved both his clinical practice and research to Stanford University in 2017. While on faculty at the University of Southern California he was awarded the Research Mentor Award in 2016-17.
Meet Our Team
Chrisa Faniku, PhD
Dr. Chrisa Faniku is a Postdoctoral fellow and obtained her Masters in Reproductive and Developmental Biology at St. George’s Medical School in London, UK. She worked as a Research Assistant for Dr. Tanya Shaw in King’s College London prior to pursuing her PhD in Molecular Biology from Glasgow, UK. She enjoys traveling, running, and playing tennis.
Lili He, PhD
Lili is a Life Science Research Professional who completed her PhD in Pathology and Cell Biology at the University of South Florida in 2008. She joined the Pepper Lab in 2019 and is working on vascular imaging of peripheral nerves and the role of endoneurial fibroblasts in nerve graft survival.
Max is a Neuroscience major at Santa Clara University who is a visiting student in the Pepper Lab.
Anping Xia, PhD
Dr. Anping Xia is a Senior Research Scientist specializing in inner ear research. She has been assisting and advising Dr. Pepper on the setup of his lab. She is also developing an electrophysiologic assay to assess the rodent facial nerve after injury. In her prior role, she was working in Dr. John Oghalai’s Lab in creating a transgenic mouse model, gene regulation, and gene therapy in the inner ear. In recent years, she also worked on cochlea physiology and cochlea mechanics in different animal models including mouse, gerbil, and chicken. While in Dr. Oghalai’s Lab, she trained other researchers routinely. She obtained her PhD in Neuroscience from Tohoku University, Japan, and her MD from Shandong University School of Medicine, China.
Lab Alumni (mentees)
Tiffany Wang, MD
Tiffany completed a co-first author publication that described the use of human induced pluripotent stem cells for the derivation of motor neurons. Using a mouse model of sciatic nerve injury, she successfully transplanted and engrafted these cells into immunodeficient mice. Her work was published in a JAMA-series publication. She matched at a highly competitive and sought after residency position in Otolaryngology at Harvard University, the Massachusetts Eye and Ear Infirmary, where she is completing her clinical training.
Gabriela Bobarnac, MD
Gabby focused her work as Dean’s scholar on the injury-responsive mesenchyme in the mouse facial nerve. She described a population of endoneurial fibroblasts in the facial nerve that proliferate after injury and replenish the injury site and the perineurium of the injured nerve. Her work was accepted for publication by Experimental Neurology and was featured on the cover of Volume 303 in 2018. She matched into a highly competitive residency position in Otolaryngology at the Oregon Health and Sciences University.
Ways to Get Involved
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As a translational research group, we are excited to collaborate with energetic scientists and clinician-scientists who share our passion for our mission. A limited number of research fellowship positions are offered in the lab throughout the year. Minimum length of the fellowship program is 12 months; shorter periods of time might be considered under special circumstances. Please contact us if you are interested in joining our group!
Chrisa Faniku wins the Stanford Bio-X best poster award
On February 26th, our postdoc, Chrisa Faniku, presented her poster “The Role of Hedgehog Signaling in Facial Nerve Regeneration Following Injury” at the Stanford Bio-X Interdisciplinary Initiatives Seed Grants Program Poster Session.
Bio-X program would like to congratulate her on the excellence and presentation of the poster. Of the 100 posters presented, it was selected as a winner!