Document Detail


Closure of supporting cell scar formations requires dynamic actin mechanisms.
MedLine Citation:
PMID:  17716843     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In many vertebrate inner ear sensory epithelia, dying sensory hair cells are extruded, and the apices of surrounding supporting cells converge to re-seal the epithelial barrier between the electrochemically-distinct endolymph and perilymph. These cellular mechanisms remain poorly understood. Dynamic microtubular mechanisms have been proposed for hair cell extrusion; while contractile actomyosin-based mechanisms are required for cellular extrusion and closure in epithelial monolayers. The hypothesis that cytoskeletal mechanisms are required for hair cell extrusion and supporting cell scar formation was tested using bullfrog saccules incubated with gentamicin (6h), and allowed to recover (18h). Explants were then fixed, labeled for actin and cytokeratins, and viewed with confocal microscopy. To block dynamic cytoskeletal processes, disruption agents for microtubules (colchicine, paclitaxel) myosin (Y-27632, ML-9) or actin (cytochalasin D, latrunculin A) were added during treatment and recovery. Microtubule disruption agents had no effect on hair cell extrusion or supporting cell scar formation. Myosin disruption agents appeared to slow down scar formation but not hair cell extrusion. Actin disruption agents blocked scar formation, and largely prevented hair cell extrusion. These data suggest that actin-based cytoskeletal processes are required for hair cell extrusion and supporting cell scar formation in bullfrog saccules.
Authors:
Andrew J Hordichok; Peter S Steyger
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2007-06-27
Journal Detail:
Title:  Hearing research     Volume:  232     ISSN:  0378-5955     ISO Abbreviation:  Hear. Res.     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-09-17     Completed Date:  2007-11-20     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  7900445     Medline TA:  Hear Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  1-19     Citation Subset:  IM    
Affiliation:
Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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MeSH Terms
Descriptor/Qualifier:
Actins / metabolism*
Amides / pharmacology
Animals
Anti-Bacterial Agents / toxicity
Azepines / pharmacology
Bicyclo Compounds, Heterocyclic / pharmacology
Cell Death
Cicatrix / metabolism*,  pathology,  physiopathology
Colchicine / pharmacology
Cytochalasin D / pharmacology
Gentamicins / toxicity
Hair Cells, Auditory / drug effects*,  metabolism,  ultrastructure
Immunohistochemistry
Keratins / metabolism
Microscopy, Confocal
Microscopy, Electron, Transmission
Microtubules / drug effects,  metabolism
Myosins / metabolism
Paclitaxel / pharmacology
Pyridines / pharmacology
Rana catesbeiana
Saccule and Utricle / drug effects*,  metabolism,  physiopathology,  ultrastructure
Thiazolidines / pharmacology
Time Factors
Tissue Culture Techniques
Tubulin Modulators / pharmacology*
Wound Healing / drug effects*
Grant Support
ID/Acronym/Agency:
P30 DC05983/DC/NIDCD NIH HHS; R01 DC004555-01A1S1/DC/NIDCD NIH HHS; R01 DC004555-02/DC/NIDCD NIH HHS; R01 DC004555-03/DC/NIDCD NIH HHS; R01 DC004555-05/DC/NIDCD NIH HHS; R01 DC04555/DC/NIDCD NIH HHS
Chemical
Reg. No./Substance:
0/Actins; 0/Amides; 0/Anti-Bacterial Agents; 0/Azepines; 0/Bicyclo Compounds, Heterocyclic; 0/Gentamicins; 0/Pyridines; 0/Thiazolidines; 0/Tubulin Modulators; 105637-50-1/ML 9; 138381-45-0/Y 27632; 22144-77-0/Cytochalasin D; 33069-62-4/Paclitaxel; 64-86-8/Colchicine; 68238-35-7/Keratins; 76343-93-6/latrunculin A; EC 3.6.4.1/Myosins
Comments/Corrections

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