Helicobacter pylori gamma-glutamyl transpeptidase-induced Ca2+ release via PLC-IP3 receptors in AGS cells

Abstract

In our previous study, gamma-glutamyl transpeptidase (GGT) isolated from Helicobacter pylori induced apoptosis of AGS cells. Here, we investigate Ca2+ effects on GGT-induced apoptosis. The GGT transiently and significantly increased intracellular Ca2+ concentration ([Ca2+](i)) in AGS cells in a dose-dependent manner (P < 0.05). The GGT-induced Ca2+ increase resulted from Ca2+ influx and release through the phospholipase C - inositol 1,4,5-trisphosphate (PLC-IP3) pathway. The GGT-induced apoptosis was significantly reduced by treatment with U73122 (a PLC inhibitor) and xestospongin (an IP3 receptor antagonist) (P < 0.05). These results indicate that GGT could induce apoptosis of AGS cells by high levels of [Ca2+](i).