Requirement for nitric oxide activation of p21ras/extracellular regulated kinase in neuronal ischemic preconditioning
Requirement for nitric oxide activation of p21ras/extracellular regulated kinase in neuronal ischemic preconditioning
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DOI：
10.1073/pnas.97.1.436
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发表时间：
2000-01-04
影响因子：
11.1
通讯作者：
Dawson, VL
中科院分区：
文献类型：
--
作者：
Gonzalez-Zulueta, M;Feldman, AB;Dawson, VL
神经元缺血预适应的机制尚不清楚，在这种现象中，短暂的缺血可以防止随后长时间缺血的致命影响。可以通过缺氧葡萄糖剥夺 (OGD) 在体外模拟缺血。我们在此报告，OGD 预处理以 N-甲基-D-天冬氨酸受体和 NO 依赖性但不依赖于 cGMP 的方式诱导 p21(ras) (Ras) 激活。我们证明 Pas 活性对于神经元中的 OGD 耐受是必要且充分的，Pas 的药理学抑制以及显性失活突变体 Pas 会阻止 OGD 预处理，而 Pas 的组成型活性形式可促进针对致命 OGD 损伤的神经保护。相反，OGD 预处理不需要磷脂酰肌醇 3-激酶的活性，因为用化学抑制剂或显性抑制磷脂酰肌醇 3-激酶阴性突变体对 OGD 耐受性的发展没有任何影响。此外，使用重组腺病毒和药理学抑制剂，我们发现 Pas 下游的细胞外调节激酶级联是 OGD 预处理所必需的。我们的观察表明，NO 激活 Ras/细胞外调节激酶级联是皮质神经元 OGD 耐受性发展的关键机制，这也可能在体内缺血预处理中发挥重要作用。
The mechanisms underlying neuronal ischemic preconditioning, a phenomenon in which brief episodes of ischemia protect against the lethal effects of subsequent periods of prolonged ischemia, are poorly understood. Ischemia can be modeled in vitro by oxygen-glucose deprivation (OGD), We report here that OGD preconditioning induces p21(ras) (Ras) activation in an N-methyl-D-aspartate receptor- and NO-dependent, but cGMP-independent, manner. We demonstrate that Pas activity is necessary and sufficient far OGD tolerance in neurons, Pharmacological inhibition of Pas, as well as a dominant negative mutant Pas, block OGD preconditioning whereas a constitutively active form of Pas promotes neuroprotection against lethal OGD insults, In contrast, the activity of phosphatidyl inositol 3-kinase is not required for OGD preconditioning because inhibition of phosphatidyl inositol 3-kinase with a chemical inhibitor or with a dominant negative mutant does not have any effect on the development of OGD tolerance. Furthermore, using recombinant adenoviruses and pharmacological inhibitors, we show that downstream of Pas the extracellular regulated kinase cascade is required for OGD preconditioning. Our observations indicate that activation of the Ras/extracellular regulated kinase cascade by NO is a critical mechanism for the development of OGD tolerance in cortical neurons, which may also play an important role in ischemic preconditioning in vivo.