脑缺血时NMDA受体通过Src激酶和Ca~(2+)/钙调蛋白依赖性蛋白激酶II调控ERKs激活(英文)

目的ERKs是钙依赖性激活蛋白,本研究旨在探讨钙依赖性蛋白激酶是否参与了脑缺血后ERK级联的调控。方法采用四动脉结扎诱导大鼠前脑缺血,用免疫印迹的方法观察几个钙依赖性蛋白激酶含量及活性的变化。结果致死性脑缺血以NMDA受体依赖的方式激活ERKs,并差异性上调Src和Ca2+/钙调蛋白依赖性蛋白激酶II(CaMKII)的活性。Src激酶和CaMKII的抑制剂PP2和KN62能显著的阻止缺血诱导的ERKs激活。然而,缺血诱导的Src过度激活也伴随着ERKs的活性抑制。结论致死性脑缺血刺激NMDA受体通过Src激酶和CaMKII介导ERKs活性上调,但是脑缺血诱导的Src过度激活可能也参与了ERKs信号通路的负性调控。

N-methyl-D-aspartate receptors mediate diphosphorylation of extracellular signal-regulated kinases through Src family tyrosine kinases and Ca~(2+)/calmodulin-dependent protein kinase II in rat hippocampus after cerebral ischemia

Objective: Extracellular signal-regulated kinases (ERKs) can be activated by calcium signals. In this study, we investigated whether calcium-dependent kinases were involved in ERKs cascade activation after global cerebral ischemia. Methods Cerebral ischemia was induced by four-vessel occlusion, and the calcium-dependent proteins were detected by immunoblot. Results Lethal-simulated ischemia significantly resulted in ERKs activation in N-methyl-D-aspartate (NMDA) receptor-dependent manner, accompanying with differential upregulation of Src kinase and Ca2+/calmodulin-dependent protein kinase II (CaMKII) activities. With the inhibition of Src family tyrosine kinases or CaMKII by administration of PP2 or KN62, the phosphorylation of ERKs was impaired dramatically during post-ischemia recovery. However, ischemic challenge also repressed ERKs activity when Src kinase was excessively activated. Conclusions Src family tyrosine kinases and CaMKII might be involved in the activation of ERKs mediated by NMDA receptor in response to acute ischemic stimuli in vivo, but the intense activation of Src kinase resulted from ischemia may play a reverse role in the ERKs cascade.