Inhibition of RhoA/Rho kinase pathway is involved in the beneficial effect of sildenafil on pulmonary hypertension
Inhibition of RhoA/Rho kinase pathway is involved in the beneficial effect of sildenafil on pulmonary hypertension
复制标题
DOI：
10.1038/sj.bjp.0706408
复制
发表时间：
2005-12-01
影响因子：
7.3
通讯作者：
Loirand, G
中科院分区：
文献类型：
--
作者：
Guilluy, C;Sauzeau, V;Loirand, G
1抑制5型磷酸二酯酶和抑制Rho激酶均能有效降低肺动脉高压（PH）。在这里，我们研究Rho激酶抑制是否参与了5型磷酸二酯酶抑制剂西地那非对PH的有益作用。2慢性缺氧诱导的PH大鼠与肺动脉RhoA活性增加有关，2天后达到最大值（10.7 +/- 0.9倍增加，n = 6，P < 0.001）。通过测量肌球蛋白磷酸酶靶亚基1（MYPT 1）磷酸化水平评估的Rho激酶活性也增加（对照组的5.7 +/- 0.8倍，n = 8）。（30 mg kg（-1）天（-1）; 14天）和西地那非（25 mg kg（-1）d（-1）; 14天）治疗降低PH和肺心血管重塑，抑制缺氧大鼠肺动脉MYPT 1磷酸化82.3 +/- 3%（n = 4）和76.6 +/- 2%（n = 4），4西地那非（10 μ m）对MYPT 1磷酸化的抑制作用通过血管平滑肌细胞中肌动蛋白应力纤维的损失来证明。然而，体外激酶试验表明，西地那非对Rho激酶活性没有直接抑制作用。5西地那非治疗诱导RhoA磷酸化增加，并与肺动脉中的胞质抑制蛋白鸟嘌呤解离抑制剂（GDI）相关。6我们认为，西地那非通过增强RhoA磷酸化和GIN的胞质螯合来抑制肺动脉中的RhoA/Rho激酶依赖性功能。因此，RhoA下游细胞内事件的抑制参与了西地那非对PH的有益作用。
1 Inhibition of the type 5 phosphodiesterase and inhibition of Rho kinase are both effective in reducing pulmonary hypertension (PH). Here we investigate whether Rho kinase inhibition is involved in the beneficial effect of the type 5 phosphodiesterase inhibitor sildenafil on PH.2 Chronic hypoxia-induced PH in rats is associated with an increase in RhoA activity in pulmonary artery that was maximal after 2 days (10.7 +/- 0.9-fold increase, n = 6, P < 0.001). The activity of Rho kinase assessed by measuring the level of myosin phosphatase target subunit 1 (MYPT1) phosphorylation was also increased (5.7 +/- 0.8-fold over control, n = 8).3 Chronic fasudil (30 mg kg(-1)day(-1); 14 days) and sildenafil (25 mg kg(-1)day(-1); 14 days) treatments reduced PH and pulmonary cardiovascular remodelling, and inhibited the MYPT1 phosphorylation in pulmonary artery from hypoxic rats by 82.3 +/- 3% (n = 4) and by 76.6 +/- 2% (n = 4), respectively.4 The inhibitory effect of sildenafil (10 mu m) on MYPT1 phosphorylation was demonstrated by the loss of actin stress fibres in vascular smooth muscle cells. However, in vitro kinase assays indicated that sildenafil had no direct inhibitory action on Rho kinase activity.5 Sildenafil treatment induced increased RhoA phosphorylation and association to its cytosolic inhibitory protein, guanine dissociation inhibitor (GDI) in pulmonary artery.6 We propose that sildenafil inhibits RhoA/Rho kinase-dependent functions in pulmonary artery through enhanced RhoA phosphorylation and cytosolic sequestration by GIN. The inhibition of intracellular events downstream of RhoA thus participates in the beneficial effect of sildenafil on PH.