Apelin stimulates myosin light chain phosphorylation in vascular smooth muscle cells
Apelin stimulates myosin light chain phosphorylation in vascular smooth muscle cells
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DOI：
10.1161/01.atv.0000218841.39828.91
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发表时间：
2006-06-01
影响因子：
8.7
通讯作者：
Umemura, Satoshi
中科院分区：
文献类型：
--
作者：
Hashimoto, Tatsuo;Kihara, Minoru;Umemura, Satoshi
目的：研究爱帕琳及其特异性受体APJ信号在血管平滑肌细胞（VSMCs）中的生理作用。本研究确定是否爱帕琳激活肌球蛋白轻链（MLC），在启动平滑肌contraction.Methods和结果的主要监管事件-为了评估MLC激活，我们进行了Western印迹和免疫组化研究，使用抗体对磷酸-MLC。在VSMC中，爱帕琳以浓度依赖性方式诱导MLC的磷酸化，在2分钟时达到峰值。用百日咳毒素预处理VSMCs可消除apelin诱导的MLC磷酸化。用GF-109203 X抑制蛋白激酶C（PKC）显著减弱apelin诱导的MLC磷酸化。此外，Na+/H+交换器（NHE）的特异性抑制剂甲基异丁基阿米洛利和Na+/Ca 2+交换器（NCX）的有效抑制剂KB-R7943显著抑制apelin的作用。在野生型小鼠中，apelin磷酸化血管组织中的MLC，而在APJ缺陷小鼠中，通过Western印迹和免疫组织化学，它没有反应。Apelin诱导的MLC磷酸化伴随着肌球蛋白磷酸酶靶亚基phosphorylation.Conclusions -这些结果提供了第一个证据，我们的知识apelin介导的MLC磷酸化在体外和体内，这是一个潜在的机制apelin介导的血管收缩。
Objective - Physiological roles of apelin and its specific receptor APJ signaling were investigated in vascular smooth muscle cells ( VSMCs). The present study determined whether apelin activates myosin light chain ( MLC), a major regulatory event in initiating smooth muscle contraction.Methods and Results - To assess MLC activation, we performed Western blot and immunohistochemical studies using an antibody against the phospho-MLC. In VSMCs, apelin induces the phosphorylation of MLC in a concentration-dependent manner with a peak at 2 minutes. Pretreatment of VSMCs with pertussis toxin abolishes the apelin-induced phosphorylation of MLC. Inhibition of protein kinase C ( PKC) with GF-109203X markedly attenuated the apelin-induced MLC phosphorylation. In addition, methylisobutyl amiloride, a specific inhibitor of the Na+/H+ exchanger ( NHE), and KB-R7943, a potent inhibitor for the reverse mode of the Na+/Ca2+ exchanger ( NCX), significantly suppressed the action of apelin. In wild-type mice, apelin phosphorylates MLC in vascular tissue, whereas it had no response in APJ-deficient mice by Western blot and immunohistochemistry. Apelin-induced phosphorylation of MLC was accompanied with myosin phosphatase target subunit phosphorylation.Conclusions - These results provide the first evidence to our knowledge for apelin-mediated MLC phosphorylation in vitro and in vivo, which is a potential mechanism of apelin-mediated vasoconstriction.