Document Detail


Anti-apoptotic factor z-Val-Ala-Asp-fluoromethylketone promotes the survival of cochlear hair cells in a mouse model for human deafness.
MedLine Citation:
PMID:  20394804     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A major challenge in the inner ear research field is to restore hearing loss of both non-genetic and genetic origin. A large effort is being made to protect hair cells from cell death after exposure to noise or drugs that can cause hearing loss. Our research focused on protecting hair cells from cell death occurring in a genetic model for human deafness. POU4F3 is a transcription factor associated with human hearing impairment. Pou4f3 knockout mice (Pou4f3(-/-)) have no cochlear hair cells, resulting in complete deafness. Although the hair cells appear to form properly, they progressively degenerate via apoptosis. In order to rescue the hair cells in the knockout mice, we produced explant cultures from mouse cochleae at an early embryonic stage and treated the cells with z-Val-Ala-Asp-fluoromethylketone (z-VAD-fmk), a general caspase inhibitor. Hair cell numbers in the knockout mice treated with z-VAD-fmk were significantly higher than in the untreated mice. We found that the time window that z-VAD-fmk has a protective effect is between E14.5 (P=0.001) to E16.5 (P=0.03), but not after E18.5. The source of the surviving hair cells is not due to proliferation, as measured by 5-bromo-2-deoxyuridine (BrdU) labeling, or to supporting cell transdifferentiation to hair cells, since there was no change in supporting cell numbers. Instead, the survival appears to be a direct effect of the anti-apoptotic agent on the dying hair cells with an early developmental window. These results help towards providing a comprehensive understanding of the molecular mechanisms of hair cell death, which might lead to the development of new therapeutic anti-apoptotic agents to alleviate hereditary hearing loss (HL).
Authors:
O Atar; K B Avraham
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-04-13
Journal Detail:
Title:  Neuroscience     Volume:  168     ISSN:  1873-7544     ISO Abbreviation:  Neuroscience     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-05-25     Completed Date:  2010-09-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7605074     Medline TA:  Neuroscience     Country:  United States    
Other Details:
Languages:  eng     Pagination:  851-7     Citation Subset:  IM    
Copyright Information:
Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.
Affiliation:
Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Chloromethyl Ketones / pharmacology*
Animals
Apoptosis / drug effects*
Cell Survival / drug effects
Cochlea / drug effects*,  pathology
Deafness / pathology*
Disease Models, Animal
Hair Cells, Auditory, Inner / drug effects*,  pathology
Homeodomain Proteins / genetics
Humans
Mice
Mice, Knockout
Neuroprotective Agents / pharmacology*
Transcription Factor Brn-3C / genetics
Chemical
Reg. No./Substance:
0/Amino Acid Chloromethyl Ketones; 0/Homeodomain Proteins; 0/Neuroprotective Agents; 0/Pou4f3 protein, mouse; 0/Transcription Factor Brn-3C; 0/benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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