Functional expression of TRPV channels in T cells and their implications in immune regulation

Abstract

The importance of Ca 2+ signalling and temperature in the context of T cell activation is well known. However, the molecular identities of key players involved in such critical regulations are still unknown. In this work we explored the endogenous expression of transient receptor potential vanilloid (TRPV) channels, a group of thermosensitive and non-selective cation channels, in T cells. Using flow cytometry and confocal microscopy, we demonstrate that members belonging to the TRPV subfamily are expressed endogenously in the human T cell line Jurkat, in primary human T cells and in primary murine splenic T cells. We also demonstrate that TRPV1-and TRPV4-specific agonists, namely resiniferatoxin and 4a-phorbol-12,13-didecanoate, can cause Ca 2+ influx in T cells. Moreover, our results show that expression of these channels can be upregulated in T cells during concanavalin A-driven mitogenic and anti-CD3/CD28 stimulated TCR activation of T cells. By specific blocking of TRPV1 and TRPV4 channels, we found that these TRPV inhibitors may regulate mitogenic and T cell receptor mediated T cell activation and effector cytokine(s) production by suppressing tumour necrosis factor, interleukin-2 and interferon-c release. These results may have broad implications in the context of cell-mediated immunity, especially T cell responses and their regulations, neuro-immune interactions and molecular understanding of channelopathies.

Endogenous expression of thermo-sensitive ion channels TRPV1 and TRPV4 in immune tissues of avian species (duck, Anas platyrhynchos)

“…But, this industry faces problems due to high prevalence of infectious diseases and abiotic stress factors that cumulatively affect the immune system resulting in poor production, mortality and serious economic losses. Presence of several TRP channels and especially TRPV channels has been reported in immunologically important tissues and cells from different mammalian species (Flockerzi and Nilius, 2014;Bertin et al, 2014;Majhi et al, 2015). Expression and specific localization of these thermosensitive ion channels in such tissues suggest their involvement in immune systems per se.…”

“…Expression and specific localization of these thermosensitive ion channels in such tissues suggest their involvement in immune systems per se. Indeed, several reports suggest the importance of TRPV channels in immune functions, at least in mammalian systems (Bertin et al, 2014;Majhi et al, 2015). However, similar studies have not been carried out till date to study expression pattern of different endogenous TRP channels and/or other thermosensitive channels in immune cells/tissues of avian species.…”

“…So far, TRPV1 gene has been sequenced from different species and its endogenous expression has been detected in several tissues and cells of certain species representing primarily mammals (Planells-Cases et al, 2005). Recently TRPV channels have been detected in mammalian immune cells where these channels play important roles in antigen detection, clonal selection, cytokine production and immune activation (Feske et al, 2012;Majhi et al, 2015). In addition, these channels are involved in multiple physiological and sensory processes.…”

“…Indeed, few reports have suggested the physical and functional presence of thermosensitive TRP channels in different immune cells, especially in T cells, macrophages and dendritic cells (Yamashiro et al, 2010). Recently we have demonstrated the physical and functional presence of TRPV1 and TRPV4 in T cells and have shown that these two channels are important for immune activation (Majhi et al, 2015). However, the presence of functional TRPVs in cells and tissues relevant for immunity has been reported from mammalian species only, and comprehensive information about the presence of TRPV channels in avian immune systems is still lacking.…”

“…For probing for TRPV channels expression, cells were stained with individual TRP channelsspecific antibodies (Alomone Lab) and anti CD3 antibody (Abcam) and subsequently flow cytometric analysis was performed as described previously (Majhi et al 2015). Briefly, Duck PBMCs were permeabilized with 0.1% Triton-X100, blocked with 5%BSA for 30 minutes and incubated in with anti-CD3 and anti-TRP channel antibodies overnight.…”