Transient receptor potential melastatin 7 (TRPM7) contributes to H 2O2-induced cardiac fibrosis via mediating Ca2+ influx and extracellular signal-regulated kinase 1/2 (ERK1/2) activation in cardiac fibroblasts

Abstract

Transient receptor potential melastatin 7 (TRPM7), a Ca2+- nonselective cation channel, plays a key role in the pathophysiological response of multiple cell types. However, the role of TRPM7 channels in hydrogen peroxide (H2O2)-induced cardiac fibrosis remains unclear. This study aimed to explore whether TRPM7 channels are involved in H 2O2-induced cardiac fibrosis and the underlying mechanisms. Our results showed that 2-aminoethoxydiphenylborate (2-APB), which is commonly used to block TRPM7 channels, inhibited H2O 2-induced cardiac fibrosis via attenuating the overexpression of important fibrogenic biomarkers and growth factors in cardiac fibroblasts, including collagen type I (Col I), fibronectin (FN), smooth muscle α-actin (α-SMA), connective tissue growth factor (CTGF), and transforming growth factor-β1 (TGF-β1). In addition, 2-APB also decreased H 2O2-mediated elevation of the concentration of intracellular Ca2+ ([Ca2+]i). Meanwhile, silencing TRPM7 channels by shRNA interference also impaired the increased [Ca2+]i and upregulation of Col?I, FN, α-SMA, CTGF, and TGF- β1 induced by H2O2. Furthermore, we found that H2O 2-mediated activation of extracellular signal-regulated kinase 1/2 (ERK1/2) decreased in TRPM7-shRNA cells and Ca2+-free culture media. These results demonstrated that TRPM7 channels contributed to H 2O2-induced cardiac fibrosis and suggested that this contribution may be through mediating Ca2+ influx and phosphorylation of ERK1/2. © The Japanese Pharmacological Society.