Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, 61231 Bad Nauheim, Germany.
Circulation. 2011 Mar 22;123(11):1194-204. doi: 10.1161/CIRCULATIONAHA.110.941484. Epub 2011 Mar 7.
Pulmonary arterial hypertension is characterized by a progressive increase in pulmonary vascular resistance caused by endothelial dysfunction, inward vascular remodeling, and severe loss of precapillary pulmonary vessel cross-sectional area. Asymmetrical dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, and its metabolizing enzyme dimethylarginine dimethylaminohydrolase (DDAH) play important roles in endothelial dysfunction. We investigated whether combined phosphodiesterase (PDE) 3 and 4 inhibition ameliorates endothelial function by regulating the ADMA-DDAH axis.
We investigated the effects of the PDE3/4 inhibitor tolafentrine in vitro on endothelial cell survival, proliferation, and apoptosis. Effects of tolafentrine on the endothelial nitric oxide synthase/nitric oxide pathway, DDAH expression, DDAH promoter activity, and cytokine release from endothelial cells and their subsequent influence on DDAH expression were investigated. In monocrotaline-induced pulmonary arterial hypertension in rats, the effects of inhaled tolafentrine on DDAH expression and activity were investigated. Real-time-polymerase chain reaction, immunocytochemistry, and PDE activity assays suggested high expression of PDE3 and PDE4 isoforms in endothelial cells. Treatment of endothelial cells with PDE3/4 inhibitor significantly decreased ADMA-induced apoptosis via a cAMP/PKA-dependent pathway by induction of DDAH2. Chronic nebulization of PDE3/4 inhibitor significantly attenuated monocrotaline-induced hemodynamic, gas exchange abnormalities, vascular remodeling, and right heart hypertrophy. Interestingly, PDE3/4 inhibitor treatment reduced ADMA and elevated nitric oxide/cGMP levels. Mechanistically, this could be attributed to direct modulatory effects of cAMP on the promoter region of DDAH2, which was consequently found to be increased in expression and activity. Furthermore, PDE3/4 inhibitor suppressed apoptosis in endothelial cells and increased vascularization in the lung.
Combined inhibition of PDE3 and 4 regresses development of pulmonary hypertension and promotes endothelial regeneration by modulating the ADMA-DDAH axis.
肺动脉高压的特征是肺血管阻力逐渐增加，这是由内皮功能障碍、血管内向重塑以及毛细血管前肺血管横截面积严重丧失引起的。不对称二甲基精氨酸（ADMA），一种内源性一氧化氮合酶抑制剂及其代谢酶二甲基精氨酸二甲氨基水解酶（DDAH），在内皮功能障碍中发挥重要作用。我们研究了联合磷酸二酯酶（PDE）3 和 4 抑制是否通过调节 ADMA-DDAH 轴来改善内皮功能。
我们研究了 PDE3/4 抑制剂托拉芬汀在体外对内皮细胞存活、增殖和凋亡的影响。研究了托拉芬汀对内皮一氧化氮合酶/一氧化氮途径、DDAH 表达、DDAH 启动子活性以及内皮细胞细胞因子释放及其对 DDAH 表达的后续影响。在大鼠 monocrotaline 诱导的肺动脉高压中，研究了吸入托拉芬汀对 DDAH 表达和活性的影响。实时聚合酶链反应、免疫细胞化学和 PDE 活性测定表明内皮细胞中高表达 PDE3 和 PDE4 同工酶。内皮细胞用 PDE3/4 抑制剂治疗可通过诱导 DDAH2 减少 ADMA 诱导的凋亡，通过 cAMP/PKA 依赖性途径。慢性雾化 PDE3/4 抑制剂可显著减轻 monocrotaline 诱导的血流动力学、气体交换异常、血管重塑和右心肥大。有趣的是，PDE3/4 抑制剂治疗可降低 ADMA 并提高一氧化氮/cGMP 水平。从机制上讲，这可能归因于 cAMP 对 DDAH2 启动子区域的直接调节作用，从而发现其表达和活性增加。此外，PDE3/4 抑制剂可抑制内皮细胞凋亡并增加肺部血管生成。
联合抑制 PDE3 和 4 通过调节 ADMA-DDAH 轴可逆转肺动脉高压的发展并促进内皮再生。
