Sensory hair cells undergo programmed cell death PC following trauma to the inner ear. Our laboratory has identified some of the molecules involved in hair cell death and the proposed experiments will determine whether interfering in the PCD pathway promotes functional hair cell survival in vivo. Head movements relative to gravity produce co- activation of hair cells found in the otolith organs and semicircular canals. In response to such head movements, compensatory eye movements (e.g. vestibular-ocular response, VOR) are produced so that the visual scene does not slip across the retina and cause disorientation. Chickens treated the aminoglycoside streptomycin sulfate display severe balance disorders and a loss of VOR [7]. Caspases are cysteine proteases that mediate PCD. Upon activation, caspases target critical cellular proteins leading to PCD. Cell permeable peptides (e.g. zVAD) can inhibit caspases and prevent PCD in a variety of neurons. Although numerous studies have demonstrated that caspase inhibitors can promote neuronal survival in vitro, few studies have examined the effectiveness of caspases inhibitors in vivo. Other studies have shown that general caspase inhibitors (e.g. zVAD) can promote hair cell survival in the presence of aminoglycosides in vitro [2, 3]. It is not known, however, whether hair cells that are rescued by caspase inhibition can still function as sensory receptors. To test the efficacy of zVAD in vivo, we will quantify the chick's motion-evoked VOR in aminoglycoside-/zVAD- treated animals. We will also obtain anatomical data to correlate hair cell loss with the status of the VOR.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31DC005082-02
Application #
6650979
Study Section
Communication Disorders Review Committee (CDRC)
Program Officer
Sklare, Dan
Project Start
2002-09-01
Project End
Budget Start
2002-09-01
Budget End
2003-04-09
Support Year
2
Fiscal Year
2002
Total Cost
$15,874
Indirect Cost
Name
Washington University
Department
Biology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Matsui, Jonathan I; Gale, Jonathan E; Warchol, Mark E (2004) Critical signaling events during the aminoglycoside-induced death of sensory hair cells in vitro. J Neurobiol 61:250-66
Cunningham, Lisa L; Matsui, Jonathan I; Warchol, Mark E et al. (2004) Overexpression of Bcl-2 prevents neomycin-induced hair cell death and caspase-9 activation in the adult mouse utricle in vitro. J Neurobiol 60:89-100
Matsui, Jonathan I; Haque, Asim; Huss, David et al. (2003) Caspase inhibitors promote vestibular hair cell survival and function after aminoglycoside treatment in vivo. J Neurosci 23:6111-22