VCAM-1 signals activate endothelial cell protein kinase Cα via oxidation
VCAM-1 signals activate endothelial cell protein kinase Cα via oxidation
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DOI：
10.4049/jimmunol.177.9.6379
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发表时间：
2006-11-01
影响因子：
4.4
通讯作者：
Cook-Mills, Joan M.
中科院分区：
文献类型：
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作者：
Abdala-Valencia, Hiam;Cook-Mills, Joan M.
淋巴细胞与 VCAM-1 结合激活内皮细胞 NADPH 氧化酶，从而产生 1 μM H2O2。这是 VCAM-1 依赖性淋巴细胞迁移所必需的。在这项研究中，我们确定了蛋白激酶 C α (PKC α) 在人和小鼠内皮细胞 VCAM-1 信号转导中的作用。用显性阴性 PKC α 或 PKC α 抑制剂 Ro-32-0432 或 Go-6976 预处理内皮细胞，可阻断 2 dynes/cm(2) 层流下的 VCAM-1 依赖性脾细胞迁移。 PKC α(Thr638) 的磷酸化是指示酶活性的自磷酸化位点，通过内皮细胞上 VCAM-1 的 Ab 交联或通过外源添加 1 μM H2O2 来增强。 H2O2 的清除和 NADPH 氧化酶的抑制可阻断抗 VCAM-1 刺激的 PKCThr638 磷酸化。此外，抗 VCAM-1 信号传导诱导内皮细胞 PKC α 氧化。氧化 PKC α 是 PKC α 的瞬时活性形式，不依赖二酰甘油。这种氧化被 NADPH 氧化酶的抑制所阻断。总之，VCAM-1 激活内皮细胞 NADPH 氧化酶会诱导短暂的 PKC α 激活，这对于 VCAM-1 依赖性跨内皮细胞迁移是必需的。
Lymphocyte binding to VCAM-1 activates endothelial cell NADPH oxidase, resulting in the generation of 1 mu M H2O2. This is required for VCAM-1-dependent lymphocyte migration. In this study, we identified a role for protein kinase C alpha (PKC alpha) in VCAM-1 signal transduction in human and mouse endothelial cells. VCAM-1-dependent spleen cell migration under 2 dynes/cm(2) laminar flow was blocked by pretreatment of endothelial cells with dominant-negative PKC alpha or the PKC alpha inhibitors, Ro-32-0432 or Go-6976. Phosphorylation of PKC alpha(Thr638), an autophosphorylation site indicating enzyme activity, was increased by Ab cross-linking of VCAM-1 on endothelial cells or by the exogenous addition of 1 mu M H2O2. The anti-VCAM-1-stimulated phosphorylation of PKCThr638 was blocked by scavenging of H2O2 and by inhibition of NADPH oxidase. Furthermore, anti-VCAM-1 signaling induced the oxidation of endothelial cell PKC alpha. Oxidized PKC alpha is a transiently active form of PKC alpha that is diacylglycerol independent. This oxidation was blocked by inhibition of NADPH oxidase. In summary, VCAM-1 activation of endothelial cell NADPH oxidase induces transient PKC alpha activation that is necessary for VCAM-1-dependent transendothelial cell migration.