Thursday, November 21, 2024
11/21/2024
Abstract: Sensory hair cells are required for balance function. Vestibular hair cell degeneration causes balance dysfunction/hypofunction manifested as dizziness and vertigo. While the mammalian cochlea lacks the ability to regenerate lost hair cells, a limited degree of spontaneous regeneration occurs in the utricle, a vestibular organ detecting linear acceleration. Prior studies have shown that ATOH1 overexpression can enhance the extent of hair cell regeneration, but these regenerated hair cells fail to fully mature. In preliminary experiments, we have characterized hair cell degeneration and regeneration in the mature mouse utricle in vivo, and found that transient, rather than constitutive, overexpression of ATOH1 promotes both hair cell regeneration and maturation. The first aim of this proposal is to determine if transient ATOH1 overexpression increases hair cell regeneration and maturation. Specifically, regenerated hair cells labeled via fate-mapping are probed via histology and electrophysiology to assess bundle morphology, expression of bundle proteins, mechanosensitvity, basolateral currents, and synaptic properties including vesicle release. To gain an unbiased insight into the genetic signature of regenerated hair cells, we will use single cell RNA sequencing technologies and bioinformatic approaches to delineate the transcriptomes of ATOH1-enhanced regenerated hair cells and validate them histologically. In the second aim, we will test whether transient overexpression of ATOH1 enhances regeneration and maturation of hair cells in human utricles in vitro. We will leverage our established pipeline of human utricles from organ donors and vestibular schwannoma patients, where the latter cohort shows hair cell degeneration, a low level of spontaneous hair cell regeneration and incomplete maturation. Regenerated hair cells will be assessed histologically for bundle morphology, expression of bundle and synaptic proteins and via single cell RNA sequencing to probe transcriptomes of ATOH1-enhanced regenerated human hair cells. In summary, we will apply state-of-the art technologies (gene therapy, hair cell physiology, single cell RNA-seq, bioinformatic strategies) to study vestibular hair cell regeneration in transgenic mouse models and human utricles. We have assembled a team of experts who have worked together to collect promising preliminary data. At the end of this 5-year proposal, we will have determined whether transient ATOH1 overexpression can promote regeneration and maturation of mouse and human hair cells at the histological, electrophysiological, and transcriptomic levels.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
