Exogenous nitric oxide negatively regulates the S‐nitrosylation p38 mitogen‐activated protein kinase activation during cerebral ischaemia and reperfusion

S. H. Qi, L. Y. Hao, J. Yue, Y. Y. Zong and G. Y. Zhang (2013) Neuropathology and Applied Neurobiology 39, 284–297 Exogenous nitric oxide negatively regulates the S‐nitrosylation p38 mitogen‐activated protein kinase activation during cerebral ischaemia and reperfusion Aims: A number of studies have suggested that nitric oxide (NO) plays an important role in the reactive phosphorylation of p38MAPKα (p38). However, whether S‐nitrosylation of p38 is activated by NO and the details remain unclear. The aim of the present work was to assess the activation of p38, the S‐nitrosylation site and the p38 signalling pathway in rat hippocampus and in HEK293 cell induced by exogenous NO. Methods: Primary hippocampal cultures, HEK293 cells and rat model of cerebral ischaemia/reperfusion (brain ischaemia was induced by four‐vessel occlusion procedure) were used in this study. Biotin‐switch method and immunoblotting were performed to study the S‐nitrosylation and phosphorylation of p38, and neuronal loss was observed by histology. Results: Endogenous NO increased p38 phosphorylation and S‐nitrosylation, and the activation of p38 was dependent on the S‐nitrosylation of Cys‐211, which was critical for the NO‐mediated activation of p38. The exogenous NO donor sodium nitroprusside, S‐nitrosoglutathione, 7‐nitroindazole, the inhibitor of the neuronal nitric oxide synthase, inhibited the activation of p38 signal pathway induced by cerebral ischaemia/reperfusion and attenuated the damage in rat hippocampal neurones. Moreover, the N‐methyl‐D‐aspartate receptor (NMDAR) is probably involved in the p38 activation process of S‐nitrosylation and phosphorylation. Conclusion: Endogenous NO induces the S‐nitrosylation and phosphorylation of p38 and mediates p38 signalling pathway by NMDAR, and as exogenous NO inhibits this process and is neuroprotective in rat cerebral ischaemia/reperfusion, it may make a contribution to stroke therapy.