Shiga Noriko, Hirano Katsuya, Hirano Mayumi, Nishimura Junji, Nawata Hajime, Kanaide Hideo
Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Circ Res. 2005 May 13;96(9):1014-21. doi: 10.1161/01.RES.0000165483.34603.91. Epub 2005 Apr 7.
RhoA plays a critical role in regulating NO production in cultured endothelial cells. To determine its role in in situ endothelial cells, we investigated the effects of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors and a RhoA-binding domain of Rho-kinase (RB) on vascular contractility in the isolated rabbit mesenteric artery. Ex vivo treatment of the strips with 3x10(-5) mol/L simvastatin and fluvastatin for approximately 24 to 30 hours significantly attenuated the contractile response to phenylephrine and high K+ in the presence of endothelium. The addition of N(omega)-nitro-L-arginine methyl ester and the removal of endothelium abolished the attenuation of the contractile response. The cotreatment with geranylgeranyl pyrophosphate prevented the statin-induced attenuation of the contractile response, whereas geranylgeranyl transferase inhibitor mimicked the effect of simvastatin. Treatment with simvastatin enhanced the bradykinin-induced endothelium-dependent relaxation in the mesenteric artery, whereas it had no effect on the bradykinin-induced [Ca2+]i elevation in endothelial cells of the aortic valves. Introduction of RB to the strips using a cell-penetrating peptide of Tat protein (TATHA-RB) attenuated the contractile responses in a NO-dependent manner. However, a Rac1/Cdc42-binding fragment of p21-activated protein kinase, RB without Tat peptide or TATHA-protein A had no effect. The in vivo treatment of rabbit with simvastatin and TATHA-RB attenuated the contractility in a NO-dependent manner. Simvastatin and TATHA-RB significantly upregulated eNOS in the rabbit mesenteric artery. The present study provides the first evidence that RhoA plays a physiological role in suppressing NO production in in situ endothelial cells.
RhoA在调节培养的内皮细胞中一氧化氮（NO）生成方面发挥着关键作用。为确定其在原位内皮细胞中的作用，我们研究了3-羟基-3-甲基戊二酰辅酶A还原酶抑制剂以及Rho激酶的RhoA结合结构域（RB）对离体兔肠系膜动脉血管收缩性的影响。用3×10⁻⁵ mol/L的辛伐他汀和氟伐他汀对血管条进行约24至30小时的离体处理，在有内皮的情况下，显著减弱了对去氧肾上腺素和高钾的收缩反应。添加N（ω）-硝基-L-精氨酸甲酯以及去除内皮消除了收缩反应的减弱。与香叶基香叶基焦磷酸共同处理可防止他汀类药物诱导的收缩反应减弱，而香叶基香叶基转移酶抑制剂模拟了辛伐他汀的作用。辛伐他汀处理增强了缓激肽诱导的肠系膜动脉内皮依赖性舒张，而对主动脉瓣内皮细胞中缓激肽诱导的[Ca²⁺]i升高没有影响。使用Tat蛋白的细胞穿透肽（TATHA-RB）将RB导入血管条以NO依赖的方式减弱了收缩反应。然而，p21激活蛋白激酶的Rac1/Cdc42结合片段、没有Tat肽的RB或TATHA-蛋白A没有作用。用辛伐他汀和TATHA-RB对兔子进行体内处理以NO依赖的方式减弱了收缩性。辛伐他汀和TATHA-RB显著上调了兔肠系膜动脉中的内皮型一氧化氮合酶（eNOS）。本研究首次提供证据表明RhoA在抑制原位内皮细胞中NO生成方面发挥生理作用。
