Document Detail

Dependence of regulatory volume decrease on transient receptor potential vanilloid 4 (TRPV4) expression in human corneal epithelial cells.
MedLine Citation:
PMID:  18355916     Owner:  NLM     Status:  MEDLINE    
TRPV4 is a non-selective cation channel with moderate calcium permeability, which is activated by exposure to hypotonicity. Such a stress induces regulatory volume decrease (RVD) behavior in human corneal epithelial cells (HCEC). We hypothesize that TRPV4 channel mediates RVD in HCEC. Immunohistochemistry revealed centrally and superficially concentrated TRPV4 localization in the corneal tissue. Immunocytochemical and fluorescence activated cell sorter (FACS) analyses identified TRPV4 membrane surface and cytosolic expression. RT-PCR and Western blot analyses identified TRPV4 gene and protein expression in HCEC, respectively. In addition, 4alpha-PDD or a 50% hypotonic medium induced up to threefold transient intracellular Ca2+ ([Ca2+]i) increases. Following TRPV4 siRNA HCEC transfection, its protein expression level declined by 64%, which abrogated these [Ca2+]i transients. Similarly, exposure to either ruthenium red or Ca(2+)-free Ringer's solution also eliminated this response. In these transfected cells, RVD declined by 51% whereas in the non-transfected counterpart, ruthenium red and Ca(2+)-free solution inhibited RVD by 54 and 64%, respectively. In contrast, capsazepine, a TRPV1 antagonist, failed to suppress [Ca2+]i transients and RVD. TRPV4 activation contributes to RVD since declines in TRPV4 expression and activity are associated with suppression of this response. In conclusion, there is TRPV4 functional expression in HCEC.
Zan Pan; Hua Yang; Stefan Mergler; Hongshan Liu; Souvenir D Tachado; Fan Zhang; Winston W Y Kao; Henry Koziel; Uwe Pleyer; Peter S Reinach
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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:  Cell calcium     Volume:  44     ISSN:  0143-4160     ISO Abbreviation:  Cell Calcium     Publication Date:  2008 Oct 
Date Detail:
Created Date:  2009-02-19     Completed Date:  2009-03-17     Revised Date:  2013-06-05    
Medline Journal Info:
Nlm Unique ID:  8006226     Medline TA:  Cell Calcium     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  374-85     Citation Subset:  IM    
Department of Biological Sciences, State University of New York, College of Optometry, 33 West 42nd Street, New York, NY 10036, USA.
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MeSH Terms
Calcium / metabolism*
Capsaicin / analogs & derivatives,  pharmacology
Cell Line
Coloring Agents / pharmacology
Epithelium, Corneal / drug effects,  metabolism*
Gene Knockdown Techniques
Hypotonic Solutions
Isotonic Solutions / pharmacology
RNA, Small Interfering / metabolism
Ruthenium Red / pharmacology
TRPV Cation Channels / antagonists & inhibitors,  drug effects,  metabolism*
Grant Support
NEI 04795//PHS HHS; R01 EY004795-24/EY/NEI NIH HHS
Reg. No./Substance:
0/Coloring Agents; 0/Hypotonic Solutions; 0/Isotonic Solutions; 0/RNA, Small Interfering; 0/TRPV Cation Channels; 0/TRPV4 protein, human; 11103-72-3/Ruthenium Red; 404-86-4/Capsaicin; 7440-70-2/Calcium; 8026-10-6/Ringer's solution; LFW48MY844/capsazepine

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

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