Abstract
Purpose :
TRPV cation channels are osmo-mechano-and-thermo-sensitive membrane proteins. These proteins are extensively involved in pathophysiology including inflammation and pain. Hyperosmotic tears and ocular surface inflammation are hallmarks of dry eye condition. Here we explore expression and osmotic modulation of TRPV1 and TRPV4 in human conjunctival epithelial cells (hCjE).
Methods :
hCjE cells were cultured to confluence in supplemented Keratinocyte Serum Free Medium (GIBCO). Presence of TRPV mRNA and proteins in hCjE were determined by Reverse Transcription-Quantitative-Polymerase Chain Reaction (RT-qPCR) and western blot analysis, respectively.
Results :
The RT-qPCR and western blot studies confirm the presence of TRPV1, TRPV2 and TRPV4 mRNA and proteins in hCjE cells. None of the TRPC genes were detected in the hCjE cells. Incubation of hCjE cells for 24h with 5 μM GSK 1016790A (a specific TRPV4 agonist) upregulated the TRPV4 gene by 58 folds (SEM=0.23, N=3, P=0.0001) compared to control cells. Similarly, treatment of hCjE cells with 5 μM capsaicin for 24h showed 2.6 folds (SEM=0.27, N=3, P = 0.0001) increase in TRPV1 mRNA expression compared to control cells. When cells were incubated in hyperosmotic medium (350mOsM) for 24h, TRPV1 protein level was significantly upregulated (N=3, P = 0.0008).
Conclusions :
Expression of TRPV1, TRPV2 and TRPV4 and their regulation by agonists and hyperosmotic conditions in cultured hCjE signify functional presence and possibility of using this cell as an experimental platform for studying TRPV proteins under simulated dry eye condition.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.