Novel signaling in chronic hypoxic responses in pulmonary arteries

描述（由申请人提供）：慢性缺氧（CH）发生在许多心肺疾病和高海拔居住。这种常见的临床应激导致肺动脉重构、血管收缩和高血压。这些细胞反应主要是由于PA平滑肌细胞（PASMCs）细胞内Ca浓度（[Ca2+]i，即Ca2+信号）的增加。然而，潜在的分子机制尚不完全清楚，目前治疗肺动脉高压（PH）的方法有限。基于我们的初步数据和先前的出版物，我们提出了一个非常创新的中心假设：CH引起Rieske铁硫蛋白（RISP）介导的线粒体活性氧（ROS）的产生，破坏FK506结合蛋白12.6 (FKBP12.6)/ryanodine receptor-2 （RyR2）复合物，导致RyR2功能亢进，增加Ca2+释放，激活钙调磷酸酶、活化T细胞的细胞质核因子（NFATc）和核因子- kb （NFkB）。增加PASMCs中cyclin的表达，导致PA重塑、收缩和高血压。为了验证这一令人兴奋的假设，我们将采用互补的、最先进的激光扫描共聚焦显微镜、片钳记录、基因操作、双免疫荧光染色、荧光共振能量转移和其他方法来解决以下基本问题（具体目标）：(1)在CH后小鼠PASMCs中，由于risp介导的线粒体ROS产生，FKBP12.6/RyR2复合体是否被破坏；(2) FKBP12.6/RyR2复合物的破坏是否介导ch诱导的PA重塑、收缩和高血压；(3) FKBP12.6/RyR2复合体破坏在钙调磷酸酶依赖性、NF-kB/ nfatc介导的细胞周期蛋白信号轴介导的ch诱导PAs反应中的作用？我们完全相信，这些研究结果将极大地提高我们目前对PA重塑、收缩和高血压的细胞分子机制的认识，并有助于充分了解Ca2+下游信号轴在缺氧中的作用和机制。预计该结果也可能有助于创造新的、特异性的、更有效的治疗靶点，用于治疗多环芳烃和其他相关的肺血管疾病，具有革命性的临床实践潜力。

DESCRIPTION (provided by applicant): Chronic hypoxia (CH) occurs in many cardiopulmonary diseases and high altitude residency. This common clinical stress causes the remodeling, vasoconstriction and hypertension in the pulmonary artery (PA). These cellular responses primarily result from an increase in intracellular Ca concentration ([Ca2+]i, i.e., Ca2+ signaling) in PA smooth muscle cells (PASMCs). However, the underlying molecular mechanisms are not fully understood, and current therapeutic options for pulmonary hypertension (PH) are limited. Based on our preliminary data and previous publications, we propose a very innovative central hypothesis that CH causes Rieske iron-sulfur protein (RISP)-mediated mitochondrial reactive oxygen species (ROS) production, disrupts FK506 binding protein 12.6 (FKBP12.6)/ryanodine receptor-2 (RyR2) complex, causes RyR2 hyperfunction, increases Ca2+ release, activates calcineurin, cytoplasmic nuclear factor of activated T- cells (NFATc) and nuclear factor-kB (NFkB), and increases cyclin expression in PASMCs, leading to PA remodeling, contraction and hypertension. To test this exciting hypothesis, we will employ complementary, state-of-the-art laser scanning confocal microscopy, patch clamp recording, gene-manipulation, double immunofluorescence staining, florescent resonance energy transfer, and other approaches to address the following fundamental questions (Specific Aims): (1) is the FKBP12.6/RyR2 complex disrupted as a result of RISP-mediated mitochondrial ROS production in PASMCs from mice following CH; (2) does the disruption of the FKBP12.6/RyR2 complex mediate CH-induced PA remodeling, contraction and hypertension; and (3) is the role of FKBP12.6/RyR2 complex disruption in CH-induced responses in PAs mediated by the calcineurin-dependent, NF-kB/NFATc-mediated cyclin signaling axis? We fully believe that the findings from the proposed studies will greatly improve our current knowledge of the cellular molecular mechanisms for PA remodeling, constriction and hypertension, and help to fully understand what and how Ca2+ downstream signaling axis is in hypoxic. It is expected that the results may also aid in the creation of novel, specific and more effective therapeutic targets for the treatment of PAH and other relevant pulmonary vascular diseases, with a great potential for revolutionizing clinical practices.