Role of TRPM7 Channels in Hyperglycemia-Mediated Injury of Vascular Endothelial Cells

Huawei Sun,Zhao Zeng,Tiandong Leng,Xiuren Gao,Koichi Inoue,Zhi-Gang Xiong,Shrikant Anant

doi:10.1371/journal.pone.0079540

Abstract

This study investigated the change of transient receptor potential melastatin 7 (TRPM7) expression by high glucose and its role in hyperglycemia induced injury of vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were incubated in the presence or absence of high concentrations of D-glucose (HG) for 72h. RT-PCR, Real-time PCR, Western blotting, Immunofluorescence staining and whole-cell patch-clamp recordings showed that TRPM7 mRNA, TRPM7 protein expression and TRPM7-like currents were increased in HUVECs following exposure to HG. In contrast to D-glucose, exposure of HUVECs to high concentrations of L-glucose had no effect. HG increased reactive oxygen species (ROS) generation, cytotoxicity and decreased endothelial nitric oxide synthase protein expression, which could be attenuated by knockdown of TRPM7 with TRPM7 siRNA. The protective effect of silencing TRPM7 against HG induced endothelial injury was abolished by U0126, an inhibitor of the extracellular signal-regulated kinase signaling pathway. These observations suggest that TRPM7 channels play an important role in hyperglycemia-induced injury of vascular endothelial cells.

Highlights

Diabetes mellitus is associated with vascular complications that contribute to the increased morbidity and mortality of the disease [1,2]
We examined the effect of high concentrations of D-glucose (HG) on transient receptor potential melastatin 7 (TRPM7) protein expression in Human umbilical vein endothelial cells (HUVECs)
The effect of HG on TRPM7 protein expression in HUVEC was not attributable to hyperosmolality of the medium, since addition of high concentration of L-glucose did not produce any change in the expression of TRPM7 protein

Summary

Introduction

Diabetes mellitus is associated with vascular complications that contribute to the increased morbidity and mortality of the disease [1,2]. Among the 28 unique mammalian TRP channel isoforms that have been identified, at least 19 (all of the TRPC; TRPV1, TRPV2, and TRPVV4; all of the TRPM except TRPMM5; and TRPP1 and TRPP2) are expressed in vascular endothelial cells [9,10,11]. Among these channels, TRPC1, -C4, -C6, and -M7 have been linked to endothelial barrier dysfunction and perturbed angiogenic processes [12]. The expression of TRPM7 was shown to be upregulated by H2O2 in HUVEC, which suggests that high levels of TRPM7 might represent a marker of oxidative stress in these cells [19]

Methods

Results

Conclusion