Single cell analysis of mitotic regeneration in the mouse vestibular system

University Of California, San Francisco, San Francisco CA

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Abstract

PROJECT SUMMARY (ABSTRACT) Sensorineural hearing loss and vestibular dysfunction are most common sensory disorders affecting millions worldwide1?3. Auditory and vestibular functions require mechanosensitive hair cells, with hair cell loss leading to permanent hearing loss and disabling vestibular dysfunction/hypofunction. Recently, the neonatal mouse utricle, one of five vestibular organs that relies on hair cells to detect linear acceleration, was shown to harbor robust numbers of progenitor cells6,7. However, while the existence of both mitotic and non-mitotic mechanisms in mammals is now clear, we currently lack understanding of the timing, location, and mechanisms of cell fate decisions. In other systems, like the skin, it is known that fate decisions are made downstream of stem cells and their transit amplifying populations, but we do not yet know the fates of these putative populations in the inner ear39. A central regulator of tissue homeostasis and stem cell maintenance across many organs is the Wnt pathway8, and this signaling cascade is upregulated in the inner ear12. I hypothesize that following injury, mitotic regeneration leads to different cell lineages in the neonatal utricular sensory epithelium, and that Wnt activation directs more supporting cells to adopt the mitotic cell lineage. Gaining an in-depth understanding of the sequence of events that drive mitotic regeneration post injury will reveal potential approaches to regenerate hair cells and supporting cells, with the ultimate goal of restoring hearing and balance functions. As a surgeon-scientist with a passion for treating patients with hearing and balance disorders, I am well equipped to tackle the scientific questions outlined. My interests in the basic sciences stem from my undergraduate years working on the genetics and development of the somatosensory cortex and studying the olfactory system. During medical school, I saw the lack of therapies of patients with permanent hearing loss as an opportunity, working on hair cell regeneration under the tutelage of renowned scientists, including Dr. Stefan Heller and Dr. Roel Nusse (Jan et al., 2013, Development). As a resident in otolaryngology, I focused on gaining the clinical and surgical expertise to treat patients and had the opportunity to continue basic science research with a focus on hearing loss under Dr. Konstantina Stankovic. In order to gain advanced surgical skills and learn state of the art techniques to study inner ear regeneration, I completed the T32 funded Clinician Scientist Training Program in Otology & Neurotology. This program further allowed me to collect preliminary data and chart my goals for this proposal as a new faculty member at UCSF. While I have extensive training in inner ear biology, my knowledge is lacking in advanced mouse genetics, new single cell RNAseq technologies, and advanced bioinformatics. Under the guidance of renowned stem cell physician-scientist Dr. Ophir Klein as my mentor at UCSF, and expert inner ear surgeon-scientist, Dr. Alan Cheng as my co-mentor at Stanford, I am confident this award will prepare me for scientific independence through the R01 grant mechanism.