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

项目摘要/摘要 肺动脉高压(PH)在左心衰中很常见，在两种心力衰竭中都存在，且 射血分数和心力衰竭保留射血分数(HFpEF)。HFpEF困扰约32人 全球有100万人，五年死亡率和再住院率估计分别为75.7%和84%。 83%的HFpEF(PH-HFpEF)患者存在PH，且预示着更差的预后。PH-HFpEF被归类 单纯性毛细血管后肺动脉高压(IPCPH)和毛细血管前、后联合肺动脉高压 高血压(CPCPH)。这两种形式的特征都是肺动脉平均压和楔压升高， 但两者之间的显著特征是CPCPH患者存在肺血管阻力升高， 由于固有的肺血管收缩和血管重塑。CPCPH增加了死亡率和 与IPCPH相比，住院风险。目前还没有被证实或批准的治疗PH-HFpEF和发现 NHLBI已将一种治疗确定为未得到满足的需求。我们发表了线粒体衍生的反应性 代谢综合征和最大强度运动所产生的氧物种(MRO)在慢性PCPH下降中的作用 下调一氧化氮受体可溶性鸟苷环化酶亚单位b1的表达 SGC转录因子核因子Y亚单位α(NFYα)的表达。下调对SGCLead的监管 降低损害肺动脉的环磷酸鸟苷(CGMP)的扩血管浓度 血管扩张。此外，MROS还可减少肺动脉平滑肌细胞(PASMC)的凋亡和 通过增加PASMCs的细胞内钙离子来增加血管张力。这项提议的长期目标是 是测试丝裂原喹酚，一种针对线粒体的抗氧化剂，用于治疗CPCPH。米托喹酚被选为 因为它是线粒体特有的，在人类身上使用是安全的，允许翻译我们的发现。我们 假设丝裂原喹酚处理CPCPH大鼠的PASMCs将减少MROs的形成和 挽救NFYα-sGC的表达，增加PASMC的凋亡和抑制其增殖(Aim 1)； 米托喹酚治疗大鼠CPCPH模型可通过降低MRO降低大鼠的肺动脉压 肺动脉的平滑肌细胞层(目标2)。我们实验室已经建立了细胞培养模型 诱导MRO，检测NFYα-sGC表达、细胞凋亡和增殖情况。此外，我们还开发了 CPCPH大鼠模型及其在安静和运动中测量肺动脉血流动力学的方法。 心脏评估将使用超声波进行补充。完成拟议的目标将确定MRO 作为CPCPH的治疗靶点，并为临床试验设计铺平道路，因为米托喹酚已被发现是安全的 在人类身上。这些成果，除了职业发展、指导培训和授课研讨会外，还将 为主要调查员提供背景知识、技术专长和领导技能 作为一名内科科学家迈向科学独立所必需的。本次培训的目标是 格兰特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.