Allyl isothiocyanate (AITC) activates nonselective cation currents in human cardiac fibroblasts: possible involvement of TRPA1

Gaku Oguri,Toshiaki Nakajima,Hironobu Kikuchi,Shotaro Obi,Fumitaka Nakamura,Issei Komuro

doi:10.1016/j.heliyon.2020.e05816

Abstract

The effects of allyl isothiocyanate (AITC), transient receptor potential ankyrin 1 (TRPA1) agonist, on cultured human cardiac fibroblasts were examined by measuring intracellular Ca2+ concentration [Ca2+]i and whole-cell voltage clamp techniques. AITC (200 μM) increased Ca2+ entry in the presence of [Ca2+]i. Ruthenium red (RR) (30 μM), and La3+ (0.5 mM), a general cation channel blocker, inhibited AITC-induced Ca2+ entry. Under the patch pipette filled with Cs+- and EGTA-solution, AITC induced the current of a reversal potential (Er) of approximately +0 mV. When extracellular Na+ ion was changed by NMDG+, the inward current activated by AITC was markedly reduced. La3+ and RR inhibited the AITC-induced current. The conventional RT-PCR analysis, Western blot, and immunocytochemical studies showed TRPA1 mRNA and protein expression. The present study shows the first evidence for functional Ca2+-permeable nonselective cation currents induced by AITC, possibly via TRPA1 in human cardiac fibroblast.

Highlights

Transient receptor potential ankyrin 1 (TRPA1) channel is a nonselective cation channel having ankyrin repeats on the N-terminus [1]
3) Existence of TRPA1 channel mRNA and proteins were shown by the reverse transcription-PCR (RT-PCR) analysis, immunocytochemistry and western blotting studies
These results provide the evidence for functional existence of nonselective cation channels, possibly via TRPA1 channels, activated by allyl isothiocyanate (AITC) in human cardiac fibroblasts (hCFs), by using patch clamp techniques

Summary

Introduction

Transient receptor potential ankyrin 1 (TRPA1) channel is a nonselective cation channel having ankyrin repeats on the N-terminus [1]. Conklin et al [8] reported that the TRPA1 expression in cardiomyocytes was high in the intercalated disks and involved in acrolein-induced Ca2þ increase According to these studies, TRPA1 appears to play a role in regulating cardiac function under various conditions including heart failure [5, 11]. Transient receptor potential (TRP) protein superfamily is composed of cation channels in various cells such as cardiac fibroblasts [16] They play an integral role in pathophysiological and physiological conditions. Okada et al [19] reported that the TRPA1 channel inhibitor reduced fibrosis and inflammation by inhibiting transforming growth factor-β1 signaling cascades in ocular fibroblasts These studies have shown that TRPA1 channel may become a potential therapeutic target for fibrotic reaction. Ca2þ-dependent pathways in hCFs are still not clearly known

Methods

Results

Conclusion