Vascular Smooth Muscle Function in Pulmonary Hypertension

项目摘要/摘要 肺动脉高压(PHTN)是一种复杂的进行性疾病，导致肺血管增加。 抵抗，右心衰竭，最终死亡。尽管pHTN起源于各种遗传和 作为致病原因，人们普遍认为血管壁结构的改变对各种形式的疾病都有贡献。 PHTN。细胞代谢从线粒体氧化磷酸化到有氧代谢的慢性转变 糖酵解是肺血管内过度增殖和抗凋亡表型的基础。 这些代谢紊乱伴随着H+的挤出，造成细胞内的碱性pH，而 酸化细胞外微环境；激活H+门控酸敏离子通道的条件1 (ASIC1)。ASIC1同时传导Na+和Ca~(2+)，激活导致膜去极化和多种 细胞内钙信号事件。我们之前的研究表明ASIC1在pHTN的发展中起到了作用 并与ASIC1在肺动脉平滑肌细胞膜上的定位增加有关。 肌细胞(PASMC)和线粒体中ASIC1的丢失。ASIC1在线粒体中的作用，也不是 ASIC1在代谢-线粒体功能障碍中的作用是已知的。因此，总体目标是 这一应用的目的是确定ASIC1对促进 与pHTN相关的增殖、抗凋亡表型。我们将检验核心假设，即 ASIC1参与了pHTN的代谢功能障碍，这是由于亚细胞定位和 PASMC质膜和线粒体膜电位的调节 具体目标：1)确定细胞代谢改变对ASIC1定位和激活的影响。 我们将测试增强葡萄糖摄取和随后的酸化的工作假说 PHTN的细胞外微环境导致ASIC1在血浆中的定位/激活增加 膜、质膜去极化和增殖。2)检查的功能角色 线粒体ASIC1(MtASIC1)在线粒体膜电位(m)调节和细胞凋亡中的作用。 我们将检验mtASIC1有助于线粒体m去极化和mtASIC1的工作假说。 细胞凋亡。此外，pHTN中mtASIC1的缺失导致线粒体m超极化和 抗细胞凋亡。拟议研究的成功完成预计将确定ASIC1在 调节线粒体动力学和代谢功能障碍。这些结果将使一个根本的 了解ASIC1在各种增生性和退行性疾病中的作用，这将使未来的研究能够 评估ASIC1的治疗潜力。

PROJECT SUMMARY/ABSTRACT Pulmonary hypertension (pHTN) is a complex, progressive condition leading to increased pulmonary vascular resistance, right heart failure and ultimately death. Although pHTN arises from a variety of genetic and pathogenic causes, it is widely recognized that structural alterations in the vascular wall contribute to all forms of pHTN. A chronic shift in cellular metabolism from mitochondrial oxidative phosphorylation to aerobic glycolysis underlies the hyperproliferative and anti-apoptotic phenotype within the pulmonary vasculature. These metabolic derangements are accompanied by H+ extrusion creating an alkalotic intracellular pH while acidifying the extracellular microenvironment; conditions that activate the H+-gated acid sensing ion channel 1 (ASIC1). ASIC1 conducts both Na+ and Ca2+ and activation leads to membrane depolarization and variety of intracellular Ca2+ signaling events. Our previous studies show ASIC1 contributes to the development of pHTN and is associated with greater localization of ASIC1 at the plasma membrane of pulmonary arterial smooth muscle cells (PASMC) and loss of ASIC1 in the mitochondria. Neither the role of ASIC1 in the mitochondria, nor the contribution of ASIC1 to metabolic-mitochondrial dysfunction are known. Therefore, the overall objective of this application is to determine the contribution of ASIC1 to the metabolic derangements that promote a proliferative, apoptosis-resistant phenotype associated with pHTN. We will test the central hypothesis that ASIC1 contributes to metabolic dysfunction in pHTN as a result of altered subcellular localization and regulation of PASMC plasma membrane and mitochondrial membrane potential with the following two specific aims: 1) Determine the impact of altered cellular metabolism on ASIC1 localization and activation. We will test the working hypothesis that enhanced glucose uptake and subsequent acidification of the extracellular microenvironment in pHTN leads to increased localization/activation of ASIC1 at the plasma membrane, plasma membrane depolarization, and proliferation. 2) Examine the functional role of mitochondrial ASIC1 (mtASIC1) in regulation of mitochondrial membrane potential (m) and apoptosis. We will test the working hypothesis that mtASIC1 contributes to mitochondrial m depolarization and apoptosis. Furthermore, loss of mtASIC1 in pHTN leads to mitochondrial m hyperpolarization and apoptosis-resistance. Successful completion of the proposed studies is expected to define a role for ASIC1 in regulating mitochondrial dynamics and metabolic dysfunction. These outcomes will enable a fundamental understanding of ASIC1 in various proliferative and degenerative diseases, which will permit future studies to evaluate the therapeutic potential of ASIC1.