Protein kinase D protects against oxidative stress-induced intestinal epithelial cell injury via Rho/ROK/PKC-δ pathway activation
Protein kinase D protects against oxidative stress-induced intestinal epithelial cell injury via Rho/ROK/PKC-δ pathway activation
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DOI：
10.1152/ajpcell.00486.2005
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发表时间：
2006-06-01
影响因子：
5.5
通讯作者：
Chung, DH
中科院分区：
文献类型：
--
作者：
Song, J;Li, J;Chung, DH
蛋白激酶D（PKD）是一种新型的丝氨酸蛋白激酶，近年来被发现参与多种细胞功能，包括细胞凋亡和细胞增殖。本研究的目的是：1）确定经H2 O2（一种诱导氧化应激的试剂）处理的肠上皮细胞中PKD的活化; 2）描绘介导PKD活化的上游信号传导机制。我们发现，PKD的激活是由H2 O2诱导的剂量和时间依赖性的方式。PKD磷酸化减弱rottlerin，一种选择性的PKC-δ抑制剂，和针对PKC-δ的小干扰RNA（siRNA），表明PKD活性的调节上游PKC-δ。PKD的激活也被Rho激酶（ROK）特异性抑制剂Y-27632以及Rho蛋白抑制剂C3阻断，表明Rho/ROK途径也介导肠细胞中的PKD活性。此外，H2 O2诱导的PKC-δ磷酸化被C3处理抑制，进一步表明PKC-δ是Rho/ROK的下游。有趣的是，PKD siRNA增强了H2 O2诱导的肠细胞凋亡。总之，这些结果清楚地表明，氧化应激诱导肠上皮细胞中的PKD活化，并且这种活化受上游PKC-δ和Rho/ROK途径调节。更重要的是，我们的研究结果表明PKD激活保护肠上皮细胞免受氧化应激诱导的凋亡.这些发现对与氧化应激相关的肠损伤具有潜在的临床意义（例如，例如，在一个实施例中，婴儿坏死性小肠结肠炎）。
Protein kinase D (PKD) is a novel protein serine kinase that has recently been implicated in diverse cellular functions, including apoptosis and cell proliferation. The purpose of our present study was 1) to define the activation of PKD in intestinal epithelial cells treated with H2O2, an agent that induces oxidative stress, and 2) to delineate the upstream signaling mechanisms mediating the activation of PKD. We found that the activation of PKD is induced by H2O2 in both a dose- and time-dependent fashion. PKD phosphorylation was attenuated by rottlerin, a selective PKC-delta inhibitor, and by small interfering RNA (siRNA) directed against PKC-delta suggesting the regulation of PKD activity by upstream PKC-delta. Activation of PKD was also blocked by a Rho kinase (ROK)-specific inhibitor, Y-27632, as well as by C3, a Rho protein inhibitor, demonstrating that the Rho/ROK pathway also mediates PKD activity in intestinal cells. In addition, H2O2-induced PKC-delta phosphorylation was inhibited by C3 treatment, further suggesting that PKC-delta is downstream of Rho/ROK. Interestingly, H2O2-induced intestinal cell apoptosis was enhanced by PKD siRNA. Together, these results clearly demonstrate that oxidative stress induces PKD activation in intestinal epithelial cells and that this activation is regulated by upstream PKC-delta and Rho/ROK pathways. Importantly, our findings suggest that PKD activation protects intestinal epithelial cells from oxidative stress- induced apoptosis. These findings have potential clinical implications for intestinal injury associated with oxidative stress (e. g., necrotizing enterocolitis in infants).