The activation of high mobility group Box1 and toll-like receptor 4 is involved in clopidogrel-induced gastric injury through p38 MAPK.

Abstract

Clopidogrel-induced gastric injury is an important clinical problem. However, the exact mechanism was still unclarified. This study aimed to investigate the role of high mobility group box protein 1 (HMGB1) and the toll-like receptor 4 (TLR4) pathway in normal human gastric epithelial (GES-1) cells under clopidogrel exposure. Morphological alterations of the gastric epithelial cells were observed under a microscope. A laser scanning confocal microscope was used to determine the distribution of HMGB1 and TLR4 in clopidogrel-induced injury. MTT was used to compare the viability of GES-1 cell among the pretreated Cli-095 (TLR4 inhibitor) group, pretreated ethyl pyruvate (HMGB1 inhibitor) group, clopidogrel group, and control group. Moreover, expression of the HMGB1, TLR4, tight junction (TJ) proteins occludin and the phosphorylation of the mitogen-activated protein kinases (MAPK) p38 were examined by western blot. We found the expression of HMGB1 and TLR4 in the cytoplasm increased after clopidogrel administration. Besides, inhibited TLR4, which is a receptor of HMGB1, prevented the injury and occludin reducing caused by clopidogrel challenge. Furthermore, blocking HMGB1 or TLR4 activity by ethyl pyruvate (HMGB1 inhibitor) or cli-095(TLR4 inhibitor) can partially diminish the activation of p38MAPK. Gastric mucosal damages observed by clopidogrel challenge are associated with HMGB1, TLR4, through p38MAPK signal pathway.