Document Detail


Supporting cells eliminate dying sensory hair cells to maintain epithelial integrity in the avian inner ear.
MedLine Citation:
PMID:  20844149     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Epithelial homeostasis is essential for sensory transduction in the auditory and vestibular organs of the inner ear, but how it is maintained during trauma is poorly understood. To examine potential repair mechanisms, we expressed β-actin-enhanced green fluorescent protein (EGFP) in the chick inner ear and used live-cell imaging to study how sensory epithelia responded during aminoglycoside-induced hair cell trauma. We found that glial-like supporting cells used two independent mechanisms to rapidly eliminate dying hair cells. Supporting cells assembled an actin cable at the luminal surface that extended around the pericuticular junction and constricted to excise the stereocilia bundle and cuticular plate from the hair cell soma. Hair bundle excision could occur within 3 min of actin-cable formation. After bundle excision, typically with a delay of up to 2-3 h, supporting cells engulfed and phagocytosed the remaining bundle-less hair cell. Dual-channel recordings with β-actin-EGFP and vital dyes revealed phagocytosis was concurrent with loss of hair cell integrity. We conclude that supporting cells repaired the epithelial barrier before hair cell plasmalemmal integrity was lost and that supporting cell activity was closely linked to hair cell death. Treatment with the Rho-kinase inhibitor Y-27632 did not prevent bundle excision but prolonged phagocytic engulfment and resulted in hair cell corpses accumulating within the epithelium. Our data show that supporting cells not only maintain epithelial integrity during trauma but suggest they may also be an integral part of the hair cell death process itself.
Authors:
Jonathan E Bird; Nicolas Daudet; Mark E Warchol; Jonathan E Gale
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  30     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-16     Completed Date:  2010-10-25     Revised Date:  2013-05-27    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  12545-56     Citation Subset:  IM    
Affiliation:
UCL Ear Institute, University College London, London WC1X 8EE, United Kingdom. birdjo@nidcd.nih.gov
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MeSH Terms
Descriptor/Qualifier:
Actin Cytoskeleton / physiology,  ultrastructure
Aminoglycosides / toxicity
Animals
Cell Communication / physiology
Cell Death / drug effects,  physiology
Cell Membrane / physiology,  ultrastructure
Chickens
Cilia / physiology,  ultrastructure
Cochlea / cytology,  growth & development
Epithelial Cells / cytology*,  physiology*
Green Fluorescent Proteins / genetics,  metabolism
Hair Cells, Auditory / cytology,  physiology*
Homeostasis / physiology
Labyrinth Supporting Cells / cytology*,  physiology*
Neurotoxins / toxicity
Organ Culture Techniques
Phagocytosis / drug effects,  physiology
Regeneration / physiology
Grant Support
ID/Acronym/Agency:
R01 DC006283-02/DC/NIDCD NIH HHS; R01DC006283/DC/NIDCD NIH HHS; //Medical Research Council
Chemical
Reg. No./Substance:
0/Aminoglycosides; 0/Neurotoxins; 0/enhanced green fluorescent protein; 147336-22-9/Green Fluorescent Proteins
Comments/Corrections

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