Phenylephrine induces elevated RhoA activation and smooth muscle alpha-actin expression in Pkd2+/- vascular smooth muscle cells.
Phenylephrine induces elevated RhoA activation and smooth muscle alpha-actin expression in Pkd2+/- vascular smooth muscle cells.
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去氧肾上腺素诱导 Pkd2/- 血管平滑肌细胞中 RhoA 活化和平滑肌 α-肌动蛋白表达升高。
DOI：
10.1038/hr.2009.173
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Qian,Qi
中科院分区：
文献类型：
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作者：
Du,Hui;Wang,Xiangling;Wu,Jun;Qian,Qi
常染色体显性遗传性多囊肾病(ADPKD)血管并发症的机制尚未完全阐明。然而，在PKD突变的血管平滑肌细胞(VSMCs)中发生变化的分子成分正在逐渐被鉴定。PKD2+/−的动脉平滑肌表现为(1)苯肾上腺素(PE)诱导的非钙非依赖性血管收缩和(2)平滑肌肌动蛋白(α-Actin)的表达增加。由于这两个过程受到RhoA信号和细胞丝状到球状(F/G)-肌动蛋白动力学的严重影响，我们检测了PE诱导的野生型(Wt)和PKD2+/−VSMC中RhoA激活和F/G-SMA比值的变化；我们进一步检验了PE的异常反应和由此导致的F/G-SMA比值升高导致PKD2+/−VSMC中SMA表达旺盛的假设。用RhoA激活法和活体F-to-G-actin法检测小鼠主动脉中膜和原代培养的VSMC的GTP-RhoA和F/G-SMA。免疫荧光法检测心肌肌钙蛋白相关转录因子-A(MRTF-A)的表达，免疫印迹法检测核内MRTF-A的表达，荧光素酶报告法检测SMA的表达。PE诱导的pKD2+/−的RhoA活性是wtVSMC的3倍，并且下游p-LIMK和p-cofilin的水平也更高。此外，PKD2+/−VSMC在基础状态和PE诱导的F/G-SMA比值较高。F/G-SMA升高促进了MRTF-A的核转位，从而上调了SMA转录。综上所述，PE诱导的RhoA过度激活和F-GSMA平衡缺陷可能参与了PKD2+/−动脉血管收缩和SMA表达的异常。这些缺陷可能导致ADPKD血管并发症的发生，从而为进一步的研究和治疗靶向提供新的领域。
The mechanisms underlying vascular complications in autosomal-dominant polycystic kidney disease (ADPKD) have not been fully elucidated. However, molecular components altered in Pkd mutant vascular smooth muscle cells (VSMCs) are gradually being identified. Pkd2+/− arterial smooth muscles show elevated levels of (1) phenylephrine (PE)-induced, Ca 2+-independent vasocontraction and (2) smooth muscle α-actin (SMA) expression. As these two processes are heavily influenced by RhoA signaling and by cellular filamentous-to-globular (F/G)-actin dynamics, we examined PE-induced changes in RhoA activation and the F/G-SMA ratio in wild-type (wt) and Pkd2+/− VSMCs; we further tested the hypothesis that the abnormal response to PE and the resultant elevation in the F/G-SMA ratio contribute to the exuberant SMA expression in Pkd2+/− VSMCs. GTP-RhoA and F/G-SMA in mouse aortic media and primary cultured VSMCs were determined using RhoA activation and in vivo F-to-G-actin assays. Myocardin-related transcription factor-A (MRTF-A)(SMA transcription coactivator) was localized by immunofluorescence, nuclear MRTF-A quantified by western analysis using nuclear extracts and SMA expression by luciferase reporter assay. PE induced a> 3-fold higher RhoA activation in Pkd2+/− than in wt VSMCs and higher levels of downstream p-LIMK and p-cofilin. Moreover, Pkd2+/− VSMCs showed a higher baseline and PE-induced F/G-SMA ratio. The F/G-SMA elevation enhanced nuclear translocation of MRTF-A, which upregulated SMA transcription. In summary, PE-induced RhoA hyperactivation and defects in F-to-G SMA balance likely have a role in the abnormal vasocontraction and SMA expression in Pkd2+/− arteries. These defects could potentially contribute to the genesis of vascular complications in ADPKD, thus providing new areas for further research and therapeutic targeting.