|Title||FUNCTIONAL EXPRESSION OF TRANSIENT RECEPTOR POTENTIAL VANILLOID 1 (TRPV1) IN CORNEAL EPITHELIAL CELLS|
|Author, Co-Author||Fan Zhang, Zan Pan, Hua Yang, Zheng Wang, Peter Reinach|
|Abstract|| PURPOSE: Transient receptor potential vanilloid 1 (TRPV1) subfamily is a molecular integrator of a variety of noxious stimuli. TRPV1 expression has been recently described in some epithelial tissues and induces proinflammatory cytokine release. We sought to determine in human corneal epithelial cells (HCEC) the involvement of TRPV1 in inducing proinflammatory cytokine release.
METHODS: Western Blot analysis and immunocytochemistry identified TRPV1 expression in primary and SV40-immortalized human corneal epithelial cells. The effects of the TRPV1 agonists, capsaicin (CAP) and resiniferatoxin (RTX) on [Ca2+]i were determined in fura2-AM-loaded HCEC using a single-cell fluorescence video imaging system. ELISA quantified CAP-induced increases in proinflammatory cytokine (i.e.IL-8 and IL-6) release.
RESULTS: TRPV1 expression was detected in HCEC and localized in the cell margins. CAP induced a dose-dependent increase in [Ca2+]i, with a maximal increase occurring at 1 μM. RTX (10 nM), a more potent TRPV1 receptor agonist, induced a [Ca2+]i transient of the same magnitude as that obtained with CAP. Pretreatment with the TRPV1 receptor antagonist capsazepine (CPZ) blocked its activation. CAP (1 μM) maximally increased IL-8 and IL-6 8- and 4- fold release, respectively. Such rises were completely suppressed by either CPZ (10 μM) or [Ca2+]i free medium.
CONCLUSIONS: TRPV1 receptor is functionally expressed in corneal epithelial cells. Its stimulation in HCEC induces increases in proinflammatory cytokine release. These results suggest that epithelial TRPV1 receptors could be essential for mounting proinflammatory reactions to environmental insults.
ADDITIONAL COMMENTS: NIH Grant EY04795
|Affiliation of Co-Authors||State University of New York, College of Optometry, State University of New York, College of Optometry, State University of New York, College of Optometry, State University of New York, College of Optometry|