Targeting mitochondria-derived reactive oxygen species as a therapy for combined pre- and post-capillary pulmonary hypertension

项目总结/摘要 肺动脉高压（PH）常见于左心衰，并存在于两种心衰， 射血分数和射血分数保留的心力衰竭（HFpEF）。HFpEF困扰约32人 全球有100万人，五年死亡率和再入院率估计分别为75.7%和84%。 PH存在于83%的HFpEF患者（PH-HFpEF）中，并预示着预后不良。PH-HFpEF分类 在单独的毛细血管后肺动脉高压（IpcPH）和合并的毛细血管前和后肺动脉高压中， 高血压（CpcPH）。两种形式的特征都是肺动脉平均压和楔压增加， 但两者之间的显著特征是CpcPH中存在升高的肺血管阻力， 这是由于固有的肺血管收缩和血管重塑。CpcPH导致死亡率增加， 与IpcPH相比的住院风险。目前尚无经证实或批准的PH-HFpEF治疗方法， NHLBI已将治疗确定为未满足的需求。我们发表了一项研究， 代谢综合征和最大强度运动产生的氧自由基（mROS）减少 一氧化氮受体可溶性鸟苷酸环化酶亚单位b1（sGCb 1）的表达，通过下调 sGC转录因子核因子Y亚基α（NFYα）的表达。sGC导联下调 降低血管舒张性环磷酸鸟苷（cGMP）的浓度，损害肺动脉 血管舒张此外，mROS减少肺动脉平滑肌细胞（PASMC）凋亡， 通过增加PASMCs中的细胞内钙来增加血管张力。本提案的长期目标 是测试米托喹醇，一种靶向抗氧化剂作为CpcPH的治疗。选择了米托喹诺 因为它是线粒体特异性的，对人类使用是安全的，允许我们的发现转化。我们 假设来自CpcPH大鼠PASMC的米托喹处理将减少mROS形成， 目的1：拯救NFYα-sGC的表达，增加PASMCs的凋亡，降低其增殖; 大鼠CpcPH模型的米托喹治疗将通过降低mROS来降低肺动脉压， 肺动脉的平滑肌细胞层（Aim 2）。本实验室建立了细胞培养模型， 诱导mROS，检测NFYα-sGC表达、细胞凋亡和增殖。此外，我们还开发了 CpcPH大鼠模型和在休息和运动期间测量肺动脉血流动力学的方法。 将使用超声辅助心脏评价。完成拟议目标将确定mROS 作为CpcPH的治疗靶点，并为临床试验设计铺平道路，因为已发现米托喹是安全的 在人类身上。除了职业发展、辅导培训和教学研讨会之外，这些成果还将 为主要研究者提供背景知识、技术专业知识和领导技能 作为一名物理学家和科学家，这是走向科学独立的必要条件。本次培训的目的 赠款将在匹兹堡大学血管医学研究所进行。

PROJECT SUMMARY/ABSTRACT Pulmonary hypertension (PH) is common in left heart failure and is present in both heart failure with reduced ejection fraction and heart failure with preserved ejection fraction (HFpEF). HFpEF afflicts approximately 32 million people globally with five year mortality and readmission rates estimated at 75.7% and 84%, respectively. PH is present in 83% of patients with HFpEF (PH-HFpEF) and portends worse prognosis. PH-HFpEF is classified in isolated post-capillary pulmonary hypertension (IpcPH) and combined pre- and post-capillary pulmonary hypertension (CpcPH). Both forms are characterized by increased pulmonary artery mean and wedge pressures, but the distinctive hallmark between the two is the presence of elevated pulmonary vascular resistance in CpcPH, due to intrinsic pulmonary vasoconstriction and vascular remodeling. CpcPH confers increased mortality and hospitalization risk compared to IpcPH. There are no proven or approved treatments for PH-HFpEF and finding a treatment has been identified as an unmet need by the NHLBI. We published that mitochondria-derived reactive oxygen species (mROS) produced by metabolic syndrome and maximal intensity exercise in CpcPH decrease the expression of the nitric oxide receptor soluble guanylate cyclase subunit b1 (sGCb1) by downregulating the expression of the sGC transcription factor Nuclear Factor Y subunit alpha (NFYα). Downregulation of sGC leads to lower concentration of the vasodilatory cyclic guanosine monophosphate (cGMP) impairing pulmonary artery vasodilation. Additionally, mROS decrease pulmonary artery smooth muscle cell (PASMC) apoptosis and increase vascular tone by increasing intracellular calcium in PASMCs. The long-term objective of this proposal is to test mitoquinol, a mitochondria-targeted antioxidant as treatment for CpcPH. Mitoquinol was chosen because it is mitochondria specific, and safe for use in humans, allowing for translation of our findings. We hypothesize that mitoquinol treatment of PASMCs from rats with CpcPH will decrease mROS formation and rescue NFYα-sGC expression, increase apoptosis and decrease proliferation of PASMCs (Aim 1); and mitoquinol treatment of a rat CpcPH model will decrease pulmonary artery pressures by decreasing mROS in the smooth muscle cell layer of the pulmonary artery (Aim 2). Our lab has established cell culture models to induce mROS and measure NFYα-sGC expression, cellular apoptosis and proliferation. In addition we developed a CpcPH rat model and methods to measure pulmonary artery hemodynamics at rest and during exercise. Cardiac evaluation will be supplemented using ultrasound. Completion of the proposed aims will identify mROS as a therapeutic target for CpcPH and pave the way for clinical trial design since mitoquinol has been found safe in humans. These outcomes, in addition to career development, mentored training, and didactic workshops, will provide the primary investigator with the background knowledge, technical expertise, and leadership skills necessary to proceed towards scientific independence as a physician-scientist. The objectives of this training grant will be performed at the Vascular Medicine Institute of the University of Pittsburgh.