Excellence Cluster Cardio-Pulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Germany.
Am J Respir Cell Mol Biol. 2013 Sep;49(3):358-67. doi: 10.1165/rcmb.2012-0361OC.
Alterations of mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial respiration are possible triggers of pulmonary vascular remodeling in pulmonary hypertension (PH). We investigated the role of MMP in PH and hypothesized that deletion of the mitochondrial uncoupling protein 2 (UCP2) increases MMP, thus promoting pulmonary vascular remodeling and PH. MMP was measured by JC-1 in isolated pulmonary arterial smooth muscle cells (PASMCs) of patients with PH and animals with PH induced by exposure to monocrotaline (MCT) or chronic hypoxia. PH was quantified in vivo in UCP2-deficient (UCP2(-/-)) mice by hemodynamics, morphometry, and echocardiography. ROS were measured by electron spin resonance spectroscopy and proliferation by thymidine incorporation. Mitochondrial respiration was investigated by high-resolution respirometry. MMP was increased in PASMCs of patients and in animal models of PH. UCP2(-/-) mice exhibited pulmonary vascular remodeling and mild PH compared with wild-type (WT) mice. PASMCs of UCP2(-/-) mice showed increased proliferation, MMP, and ROS release. Increased proliferation of UCP2(-/-) PASMCs could be attenuated by ROS inhibitors and inhibited by carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, which decreased MMP to the level of WT mice. Mitochondrial respiration was altered in PASMCs from MCT rats and PASMCs exposed to hypoxia but not in isolated pulmonary mitochondria of UCP2(-/-) mice or PASMCs after treatment with small interfering RNA for UCP2. Our data suggest that increased MMP causes vascular remodeling in UCP2(-/-) mice partially via increased ROS. In chronic hypoxia and MCT-induced PH, additional pathomechanisms such as decreased respiration may play a role.
线粒体膜电位 (MMP)、活性氧 (ROS) 和线粒体呼吸的改变可能是肺动脉高压 (PH) 肺血管重构的触发因素。我们研究了 MMP 在 PH 中的作用，并假设线粒体解偶联蛋白 2 (UCP2) 的缺失会增加 MMP，从而促进肺血管重构和 PH。通过 JC-1 在 PH 患者和暴露于单环酸 (MCT) 或慢性缺氧的 PH 动物的分离肺动脉平滑肌细胞 (PASMC) 中测量 MMP。通过血流动力学、形态计量学和超声心动图在 UCP2 缺陷 (UCP2(-/-)) 小鼠中体内量化 PH。通过电子自旋共振光谱测量 ROS，通过胸苷掺入测量增殖。通过高分辨率呼吸测定法研究线粒体呼吸。MMP 在 PH 患者的 PASMC 和动物模型中增加。与野生型 (WT) 小鼠相比，UCP2(-/-) 小鼠表现出肺血管重构和轻度 PH。UCP2(-/-) 小鼠的 PASMC 表现出增殖增加、MMP 和 ROS 释放增加。UCP2(-/-) PASMC 增殖增加可被 ROS 抑制剂减弱，并被羰基氰化物 4-(三氟甲氧基)苯腙抑制，后者将 MMP 降低至 WT 小鼠的水平。MCT 大鼠 PASMC 和缺氧暴露的 PASMC 的线粒体呼吸发生改变，但 UCP2(-/-) 小鼠的分离肺线粒体或 UCP2 小干扰 RNA 处理后的 PASMC 中未发生改变。我们的数据表明，增加的 MMP 通过增加的 ROS 导致 UCP2(-/-) 小鼠的血管重构。在慢性缺氧和 MCT 诱导的 PH 中，其他病理机制，如呼吸减少，可能起作用。
