Cochlear degeneration is a major cause of sensorineural hearing loss (SNHL), and the lack of spontaneous regeneration contributes to the irreversible nature of SNHL. Prior studies have examined the utility of forced differentiation of hair cells in the degenerating cochlea, yet it remains unclear whether a restoration in cell number via cell proliferation can also aid cochlear regeneration. Recent work demonstrates that activation of canonical Wnt signaling via genetic or pharmacologic manipulation induces proliferation in the neonatal cochlea. Also, the competence to proliferate in response to Wnt signals is observed in both cochlear supporting cells and tympanic border cells below the basilar membrane. The goal of this proposal is to investigate whether supplementation of Wnt signals can stimulate proliferation and/or regeneration after hair cell degeneration in both the neonatal and mature cochleae. We will initiate degeneration with aminoglycoside application or via a transgenic strategy and concurrently fate-map supporting cells and tympanic border cells in vitro and in vivo. In parallel experiments using multiple transgenic mouse strains, we will study ablation targeting sensory hair cells or supporting cell subtypes. Wnt activation is achieved by using the Cre-Lox system in transgenic mice or local application of Wnt agonists and whether they will initiate proliferation of and regeneration by supporting cells and tympanic border cells are examined. The degree of damage and possible recovery in the cochlea are examined histologically and correlated with pre- and post-treatment auditory physiology in the whole animal. To gain an unbiased insight into the genetic signature of the damaged cochlea, supporting cells and tympanic border cells from undamaged and damaged cochlea are isolated via flow cytometry and subjected to gene array analyses. All transgenic mouse strains, pharmacologic agents, expertise to manipulate and examine the cochlea in vitro and in vivo, and techniques to isolate and enrich cochlear cells are at hand. Together, our research will determine 1) whether Wnt supplementation can help initiate cochlear regeneration and 2) additional targets to enhance this regenerative process in both the neonatal and mature cochleae.

Public Health Relevance

Degeneration of inner ear sensory cell loss is a primary cause of hearing loss. At present, we rely on hearing aids and cochlear implants to improve the symptoms of hearing loss, but lack the ability to regenerate lost cells. The proposed research aims to deliver signals critical during development to stimulate the damaged inner ear to regenerate.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC013910-03
Application #
9297270
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Freeman, Nancy
Project Start
2015-07-01
Project End
2020-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
3
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Stanford University
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94304
Atkinson, Patrick J; Dong, Yaodong; Gu, Shuping et al. (2018) Sox2 haploinsufficiency primes regeneration and Wnt responsiveness in the mouse cochlea. J Clin Invest 128:1641-1656
Jan, Taha A; Jansson, Lina; Atkinson, Patrick J et al. (2016) Profiling Specific Inner Ear Cell Types Using Cell Sorting Techniques. Methods Mol Biol 1427:431-45
Huth, Markus E; Han, Kyu-Hee; Sotoudeh, Kayvon et al. (2015) Designer aminoglycosides prevent cochlear hair cell loss and hearing loss. J Clin Invest 125:583-92
Jansson, Lina; Kim, Grace S; Cheng, Alan G (2015) Making sense of Wnt signaling-linking hair cell regeneration to development. Front Cell Neurosci 9:66
Atkinson, Patrick J; Huarcaya Najarro, Elvis; Sayyid, Zahra N et al. (2015) Sensory hair cell development and regeneration: similarities and differences. Development 142:1561-71
Chai, Renjie; Kuo, Bryan; Wang, Tian et al. (2012) Wnt signaling induces proliferation of sensory precursors in the postnatal mouse cochlea. Proc Natl Acad Sci U S A 109:8167-72