Yogi A, Callera G E, Montezano A C I, Aranha A B, Tostes R C, Schiffrin E L, Touyz R M
Kidney Research Centre, University of Ottawa/Ottawa Health Research Institute, 451 Smyth Rd, Ottawa, ON, KIH 8M5.
Arterioscler Thromb Vasc Biol. 2007 Sep;27(9):1960-7. doi: 10.1161/ATVBAHA.107.146746. Epub 2007 Jun 14.
Endothelin-1 (ET-1) and angiotensin II (Ang II) activate common signaling pathways to promote changes in vascular reactivity, remodeling, inflammation, and oxidative stress. Here we sought to determine whether upstream regulators of mitogen-activated protein kinases (MAPKs) are differentially regulated by ET-1 and Ang II focusing on the role of c-Src and the small GTPase Ras.
Mesenteric vascular smooth muscle cells (VSMCs) from mice with different disruption levels in the c-Src gene (c-Src(+/-) and c-Src(-/-)) and wild-type (c-Src(+/+)) were used. ET-1 and Ang II induced extracellular signal-regulated kinase (ERK) 1/2, SAPK/JNK, and p38MAPK phosphorylation in c-Src(+/+) VSMCs. In VSMCs from c-Src(+/-) and c-Src(-/-), Ang II effects were blunted, whereas c-Src deficiency had no effect in ET-1-induced MAPK activation. Ang II but not ET-1 induced c-Src phosphorylation in c-Src(+/+) VSMCs. Activation of c-Raf, an effector of Ras, was significantly increased by ET-1 and Ang II in c-Src(+/+) VSMCs. Ang II but not ET-1-mediated c-Raf phosphorylation was inhibited by c-Src deficiency. Knockdown of Ras by siRNA inhibited both ET-1 and Ang II-induced MAPK phosphorylation.
Our data indicate differential regulation of MAPKs by distinct G protein-coupled receptors. Whereas Ang II has an obligatory need for c-Src, ET-1 mediates its actions through a c-Src-independent Ras-Raf-dependent pathway for MAPK activation. These findings suggest that Ang II and ET-1 can activate similar signaling pathways through unrelated mechanisms. MAP kinases are an important point of convergence for Ang II and ET-1.
内皮素 -1（ET-1）和血管紧张素 II（Ang II）激活共同的信号通路，以促进血管反应性、重塑、炎症和氧化应激的变化。在此，我们试图确定丝裂原活化蛋白激酶（MAPKs）的上游调节因子是否受到 ET-1 和 Ang II 的差异调节，重点关注 c-Src 和小 GTP 酶 Ras 的作用。
使用来自 c-Src 基因不同破坏水平的小鼠（c-Src(+/-)和 c-Src(-/-)）以及野生型（c-Src(+/+)）的肠系膜血管平滑肌细胞（VSMCs）。ET-1 和 Ang II 在 c-Src(+/+) VSMCs 中诱导细胞外信号调节激酶（ERK）1/2、应激激活蛋白激酶/应激活化蛋白激酶（SAPK/JNK）和 p38MAPK 磷酸化。在 c-Src(+/-)和 c-Src(-/-)的 VSMCs 中，Ang II 的作用减弱，而 c-Src 缺乏对 ET-1 诱导的 MAPK 激活没有影响。Ang II 而非 ET-1 在 c-Src(+/+) VSMCs 中诱导 c-Src 磷酸化。ET-1 和 Ang II 在 c-Src(+/+) VSMCs 中显著增加了 Ras 的效应器 c-Raf 的激活。c-Src 缺乏抑制了 Ang II 而非 ET-1 介导的 c-Raf 磷酸化。通过 siRNA 敲低 Ras 抑制了 ET-1 和 Ang II 诱导的 MAPK 磷酸化。
我们的数据表明不同的 G 蛋白偶联受体对 MAPKs 有差异调节。虽然 Ang II 对 c-Src 有必然需求，但 ET-1 通过不依赖 c-Src 的 Ras-Raf 依赖性途径介导其对 MAPK 激活的作用。这些发现表明 Ang II 和 ET-1 可通过不相关的机制激活相似的信号通路。MAP 激酶是 Ang II 和 ET-1 的一个重要汇聚点。
