Transient Receptor Potential Ankyrin1 channel is endogenously expressed in T cells and regulates immune functions

Abstract

Transient Receptor Potential channel subfamily A member 1 (TRPA1) is a non selective cationic channel, identified initially as a cold sensory receptor. TRPA1 responds to diverse exogenous and endogenous stimuli associated with pain and inflammation. However, the role of TRPA1 towards T cell responses remains scanty. In this work, we explored the endogenous expression of TRPA1 in T cells. By RT-PCR we confirmed the expression of TRPA1 in T cell at RNA level. Using confocal microscopy as well as flow cytometry, we demonstrated that TRPA1 is endogenously expressed in primary murine splenic T cells as well as in primary human T cells. The endogenous expression of TRPA1 is confirmed by using another antibody. TRPA1 was primarily located at the cell surface. TRPA1-specific activator namely AITC increases intracellular Ca2+-levels while two different inhibitors namely A-967079 as well as HC-030031 reduce intracellular Ca2+-levels in T cells. Such Ca2+-influx can also be influenced by chelation of intracellular Ca2+ as well as extracellular Ca2+. TRPA1 expression was found to be increased during CD3/CD28 (TCR) or ConA driven stimulation in T cells. TRPA1-specific inhibitor treatment prevented induction of CD25, CD69 in ConA/TCR stimulated T cells and secretion of cytokines like TNF, IFN-{gamma} and IL-2 suggesting that endogenous activity of TRPA1 may be involved in T cell activation. Collectively these results may have implication in T cell-mediated responses and possible role of TRPA1 in immunological disorders.