Genetic and Molecular Mechanisms in Hypoxia-Induced Pulmonary Hypertension

低氧诱导的肺动脉高压(HPH)是一种增加患者死亡率的疾病 心肺疾病(如慢性阻塞性肺病)和阻塞性睡眠 呼吸暂停。涉及肺动脉平滑肌异常的多因素病因学 内皮细胞(PAEC)被认为与HPH有关。我们的数据表明，a)低氧会上调 NotchS在肺组织和PASMC中的表达；b)低氧诱导的肺血管重构受到抑制 NOTCH3基因敲除小鼠；c)Jagged1、NotchS和Hes5在肺组织和PASMC中均上调 高血压病患者与正常人和血压正常的患者比较。此外，我们的 结果表明：1)缺氧可上调心肌细胞Trp通道，增加AP-1结合活性。 低氧抑制PASMC上的Kv通道，Kv通道活性降低而Trp 与正常血压的PASMC相比，PH患者PASMC的通道活动增加 研究对象。这些数据表明Notch信号可能与离子通道(如Kv和Trp通道)相互作用 和其他信号转导在调节肺血管重塑中的级联作用，这是导致 HPH患者和动物的肺血管阻力升高。这项研究的目标是 通过与缺氧敏感的膜通道相互作用，确定Notch信号是否以及如何被 参与a)HPH的发病和进展，b)肺血管易感性的变异性 低氧。中心假设是/)选择性Notch信号基因和离子通道。 PASMC/PAEC参与低氧引起的肺血管功能/结构和//改变 这些基因在PASMC/PAEC中受缺氧的不同调控(即表达和功能)决定 对缺氧的敏感性。在这个项目中提出了三个具体目标：1)表征 急性、间歇性和持续性低氧对Notch信号转导基因表达和功能的影响 人和小鼠正常PASMC和PAEC中Kv和Trp通道的途径和编码基因；2) 检测和比较Notch信号通路基因和基因的表达和功能 编码常氧对照组和HPH小鼠PASMC和PAEC中的Kv和Trp通道； 3)检测和比较Notch信号通路和Kv中基因的表达和功能 和分离自正常血压患者的PASMC和PAEC中的Trp通道，ii)合并HPH的COPD患者， Iii)无HPH的COPD患者，以及iv)有肺动脉高压的患者。

Hypoxia-induced pulmonary hypertension (HPH) is a condition that increases mortality in patients with cardiopulmonary diseases (e.g., chronic obstructive pulmonary disease, COPD) and obstructive sleep apnea. Multifactorial etiology involving abnormalities in pulmonary artery smooth muscle (PASMC) and endothelial (PAEC) cells has been implicated in HPH. Our data demonstrate that a) hypoxia upregulates NotchS in lung fissues and PASMC; b) hypoxia-induced pulmonary vascular remodeling is inhibited in Notch3 knockout mice; and c) Jaggedl, NotchS and Hes5 are all upregulated in lung fissues and PASMC from pafients with PH compared with normal subjects and normotensive patients. Furthermore, our observations indicate that: /) hypoxia upregulates TRP channels and increases AP-1 binding activity in PAEC; /¿/) hypoxia inhibits Kv channels in PASMC; and ///} Kv channel activity is decreased whereas TRP channel acfivity is increased in PASMC from PH patients compared with PASMC from normotensive subjects. These data imply that Notch signaling may interact with ion channels (e.g., Kv and TRP channels) and other signal transducfion cascades in regulafing pulmonary vascular remodeling, a major cause for the elevated pulmonary vascular resistance in animals and pafients with HPH. The goal of this study is to determine whether and how Notch signaling, by interacting with hypoxia-sensitive membrane channels, is involved in a) the inifiafion and progression of HPH and b) the variability of pulmonary vascular suscepfibility to hypoxia. The central hypotheses are that /) selective Notch signaling genes and ion channels in PASMC/PAEC are involved in hypoxia-mediated changes in pulmonary vascular funcfion/structure and //) differenfial regulafion of these genes (i.e., expression and function) by hypoxia in PASMC/PAEC determines hypoxia susceptibility. Three Specific Aims are proposed in this project: 1) To characterize the effects of acute, intermittent and sustained hypoxia on the expression and function of genes in the Notch signaling pathway and genes encoding Kv and TRP channels in normal PASMC and PAEC from humans and mice; 2) To determine and compare the expression and function of genes in the Notch signaling pathway and genes encoding Kv and TRP channels in PASMC and PAEC isolated from normoxic control mice and HPH mice; and 3) To determine and compare expression and funcfion of genes in the Notch signaling pathway and Kv and TRP channels in PASMC and PAEC isolated from /) normotensive pafients, ii) COPD patients with HPH, iii) COPD pafients without HPH, and iv) pafients with pulmonary arterial hypertension.