Birds are the only warm-blooded vertebrates known to regenerate sensory hair cells (HCs) of the inner ear in maturity. Recent studies have demonstrated that birds utilize two mechanisms to generate new HCs: renewed cell division of progenitor cells, the non-sensory supporting cells (SCs), and direct transdifferentiation of SCs into HCs, without intervening mitosis. Studies of avian HC regeneration offer an important opportunity to elucidate cellular and molecular mechanisms governing these SC responses to HC loss. Such studies are critical preludes for directing analyses of SC behavior in mammalian HC-epithelia toward determining why HC regeneration is not completed in mammals. We will focus on the role of two molecules, Atoh1 and Notch, which are critical for mammalian HC development.
Aim 1 will address signals regulating the SC decision to directly transdifferentiate after HC damage in mature chicken BPs by testing the hypotheses that Notch activation antagonizes transdifferentiation while Atoh1 activation promotes it. We will examine damaged BPs to determine if temporospatial expression patterns of genes in the Notch pathway support the proposed role for Notch. We will activate or inhibit Notch, its ligands, and its effectors and determine if direct transdifferentiation becomes altered in response. We will also test the hypothesis that Atoh1 function is necessary and sufficient for direct transdifferentiation.
In Aim 2, we will address signals regulating the SC decision to divide after HC damage in avian BPs by testing the hypothesis that Atoh1 and Notch both inhibit SC division. We will determine if overexpression of Atoh1 leads to cell-autonomous inhibition of SC division and if inhibition of Atoh1 promotes division. We will determine which genes in the Notch pathway are altered in dividing SCs and in cells surrounding them. We will determine if manipulation of Notch function significantly alters rates of SC division.
In Aim 3, we will assess the extent to which Atoh1 expression and direct transdifferentiation occur spontaneously in SCs of the adult mouse utricle after HC damage. We will examine how expression of genes in the Notch pathway is altered in adult mouse utricles after HC loss. We will also test the hypotheses that inhibition of Notch signaling in adult mouse utricles promotes direct transdifferentiation and SC division. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC003696-10
Application #
7371943
Study Section
Auditory System Study Section (AUD)
Program Officer
Freeman, Nancy
Project Start
1998-04-01
Project End
2012-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
10
Fiscal Year
2008
Total Cost
$327,191
Indirect Cost
Name
University of Washington
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Stone, Jennifer S; Wisner, Serena R; Bucks, Stephanie A et al. (2018) Characterization of Adult Vestibular Organs in 11 CreER Mouse Lines. J Assoc Res Otolaryngol 19:381-399
Lewis, Rebecca M; Keller, Jesse J; Wan, Liangcai et al. (2018) Bone morphogenetic protein 4 antagonizes hair cell regeneration in the avian auditory epithelium. Hear Res 364:1-11
Warchol, Mark E; Stone, Jennifer; Barton, Matthew et al. (2017) ADAM10 and ?-secretase regulate sensory regeneration in the avian vestibular organs. Dev Biol 428:39-51
Pujol, Rémy; Pickett, Sarah B; Nguyen, Tot Bui et al. (2014) Large basolateral processes on type II hair cells are novel processing units in mammalian vestibular organs. J Comp Neurol 522:3141-59
Chonko, Kurt T; Jahan, Israt; Stone, Jennifer et al. (2013) Atoh1 directs hair cell differentiation and survival in the late embryonic mouse inner ear. Dev Biol 381:401-10
White, Patricia M; Stone, Jennifer S; Groves, Andrew K et al. (2012) EGFR signaling is required for regenerative proliferation in the cochlea: conservation in birds and mammals. Dev Biol 363:191-200
Lewis, Rebecca M; Hume, Clifford R; Stone, Jennifer S (2012) Atoh1 expression and function during auditory hair cell regeneration in post-hatch chickens. Hear Res 289:74-85
Golub, Justin S; Tong, Ling; Ngyuen, Tot B et al. (2012) Hair cell replacement in adult mouse utricles after targeted ablation of hair cells with diphtheria toxin. J Neurosci 32:15093-105
Lin, Vincent; Golub, Justin S; Nguyen, Tot Bui et al. (2011) Inhibition of Notch activity promotes nonmitotic regeneration of hair cells in the adult mouse utricles. J Neurosci 31:15329-39
Shang, Jialin; Cafaro, Jon; Nehmer, Rachel et al. (2010) Supporting cell division is not required for regeneration of auditory hair cells after ototoxic injury in vitro. J Assoc Res Otolaryngol 11:203-22

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