Ca2+ Regulation in Chronic Hypoxic Pulmonary Hypertention

慢性缺氧性肺动脉高压中的 Ca2 调节

• 批准号: 7728590
• 负责人: JAMES SK SHAM
• 金额: $ 41万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-08 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7728590
• 关键词: Agonist; Animal Model; Animals; Appearance; Arts; Attenuated; Blood Vessels; Calcineurin; Cations; Cell Proliferation; Chronic; Chronic Obstructive Airway Disease; Complex; Cyclosporine; Development; Disease; Elastases; Exposure to; Failure; Funding; Gene Expression Regulation; Genes; Goals; Growth Factor; Heart Hypertrophy; Homeostasis; Hormones; Hypertrophy; Hypoxia; Hypoxia Inducible Factor; Image; Ion Channel; Knock-out; Knockout Mice; Laser Scanning Confocal Microscopy; Lobar; Lung; Lung diseases; Mechanics; Mediating; Molecular; Mus; Oxygen; Pathogenesis; Pathologic; Pathology; Pathway interactions; Patients; Peptide Hydrolases; Physiological; Play; Process; Pulmonary Hypertension; Pulmonary artery structure; Rattus; Reactive Oxygen Species; Regulation; Relative (related person); Rest; Role; Ruthenium Red; Serine; Signal Transduction; Small Interfering RNA; Smooth Muscle Myocytes; Stretching; System; T-Cell Activation; TRPV channel; Techniques; Testing; Up-Regulation; Vanilloid; Vascular remodeling; Vasoconstrictor Agents; Vasomotor; base; channel blockers; computerized data processing; design; ionic balance; knockout animal; knockout gene; member; novel; nuclear factors of activated T-cells; outcome forecast; patch clamp; pressure; public health relevance; pulmonary arterial hypertension; receptor; research study; response; transcription factor; vasoconstriction

DESCRIPTION (provided by applicant): Chronic hypoxia, as occurs in many pulmonary diseases, results in pulmonary hypertension, which is characterized by profound vascular remodeling, increase in vascular tone, and enhanced responsiveness to vasoconstrictors. These functional changes are related to major alterations in Ca2+ homeostasis and may involve multiple Ca2+ pathways in PASMCs. Transient receptor potential (TRP) gene superfamily encodes a large repertoire of non-selective ion channels with a wide-range of physiological functions. Many of them are expressed in PASMCs. We have previously shown that chronic hypoxia upregulates TRPC1 and TRPC6 expression and enhances both store- and receptor-operated Ca2+ entries in PASMCs; and store-operated Ca2+ entry is responsible for the elevated resting [Ca2+]i and basal vasomotor tone. Our preliminary studies show that the increase in pulmonary arterial pressure (Ppa) and right heart hypertrophy were blunted in hypoxic trpc1-/- mice, suggesting a major involvement of TRPC1 in hypoxic pulmonary hypertension. In addition, we found that the mechanosensitive TRPV4 is highly expressed in PAs; and is the only channel, among all members of TRPM and TRPV subfamilies, being up-regulated by chronic hypoxia. Its up-regulation is associated with enhanced stretch-activated Ca2+ influx in PASMCs and the development of myogenic tone in isolated microvessels. Moreover, development of pulmonary hypertension was significantly delayed and suppressed in trpv4-/- mice. Since mechanical stretch imposed by elevated Ppa has been implicated as a trigger for the development of pulmonary hypertension, TRPV4 may operate as a mechanosensitive pathway for signaling the processes. Enhanced Ca2+ influx through TRP channels in hypoxic PASMCs may contribute to vascular remodeling through activation of Ca2+ sensitive transcription factors. Recent studies show that the nuclear factors of activated T-cells (NFAT) are involved in gene regulation in pulmonary hypertension. Based on these findings, we propose that the enhanced Ca2+ influx through the store-operated TRPC1, the receptor- operated TRPC6, and the mechanosensitive TRPV4 in PASMCs play essential roles in the increased vascular tone, responsiveness to vasoconstrictors, as well as vascular remodeling in hypoxic pulmonary hypertension; in part through the activation of calcineurin/NFAT pathway. To test this hypothesis, we will apply a combination of state-of-the-art techniques including Ca2+ imaging, patch clamping, laser-scanning confocal microscopy, siRNA gene knockout, and isolated microvessels, in conjunction with TRP channel knockout mice to examine (1) the roles and contributions of TRPC1 and TRPC6 to the vascular pathology in hypoxic pulmonary hypertension; (2) the functions of TRPV4 and its contribution to the development of hypoxic pulmonary hypertension; and (3) the interactions of calcineurin/NFAT pathways and TRP channels in hypoxic pulmonary hypertension. This project will provide unique information on the roles of TRP channel mediated Ca2+ signaling in chronic hypoxia-induce pulmonary hypertension. PUBLIC HEALTH RELEVANCE: The development of pulmonary hypertension considerably worsens the prognosis for patients of many lung diseases, e.g. chronic obstructive airway disease, by causing right heart hypertrophy and failure. The proposed project will elucidate at the molecular and cellular level, the roles of several important TRP cation channels in the alteration of [Ca2+]i, vasomotor tone, and vascular remodeling in chronic hypoxia. The information generated by the proposed experiments may help to develop new treatments for pulmonary hypertension.

描述（由申请人提供）：慢性缺氧，如许多肺部疾病中发生的那样，导致肺动脉高压，其特征是深刻的血管重塑、血管张力增加以及对血管收缩剂的反应性增强。这些功能变化与 Ca2+ 稳态的主要改变有关，并且可能涉及 PASMC 中的多个 Ca2+ 途径。瞬时受体电位（TRP）基因超家族编码大量具有广泛生理功能的非选择性离子通道。其中许多在 PASMC 中表达。我们之前已经证明，慢性缺氧会上调 TRPC1 和 TRPC6 的表达，并增强 PASMC 中钙池和受体操纵的 Ca2+ 进入。钙库操纵的 Ca2+ 进入导致静息 [Ca2+]i 和基础血管舒缩张力升高。我们的初步研究表明，缺氧 trpc1-/- 小鼠中肺动脉压 (Ppa) 的增加和右心肥厚减弱，表明 TRPC1 在缺氧性肺动脉高压中发挥着重要作用。此外，我们发现机械敏感的TRPV4在PAs中高表达；并且是 TRPM 和 TRPV 亚家族所有成员中唯一因慢性缺氧而上调的通道。其上调与 PASMC 中拉伸激活的 Ca2+ 流入增强以及孤立微血管中肌源性张力的发展有关。此外，trpv4-/- 小鼠中肺动脉高压的发展被显着延迟和抑制。由于 Ppa 升高所施加的机械拉伸被认为是肺动脉高压发生的触发因素，TRPV4 可能作为传递该过程信号的机械敏感途径。缺氧 PASMC 中通过 TRP 通道增强的 Ca2+ 流入可能通过激活 Ca2+ 敏感转录因子而促进血管重塑。最近的研究表明，活化 T 细胞核因子 (NFAT) 参与肺动脉高压的基因调控。基于这些发现，我们提出PASMCs中通过钙池操纵的TRPC1、受体操纵的TRPC6和机械敏感的TRPV4增强的Ca2+流入在血管紧张度增加、对血管收缩剂的反应性以及血管重塑中发挥重要作用。缺氧性肺动脉高压；部分通过钙调神经磷酸酶/NFAT 途径的激活。为了检验这一假设，我们将结合使用最先进的技术，包括 Ca2+ 成像、膜片钳、激光扫描共聚焦显微镜、siRNA 基因敲除和分离微血管，并结合 TRP 通道敲除小鼠来检查（ 1）TRPC1和TRPC6在缺氧性肺动脉高压血管病理学中的作用和贡献； (2)TRPV4的功能及其对缺氧性肺动脉高压发生的贡献； (3)缺氧性肺动脉高压中钙调神经磷酸酶/NFAT途径和TRP通道的相互作用。该项目将提供关于 TRP 通道介导的 Ca2+ 信号传导在慢性缺氧诱导的肺动脉高压中的作用的独特信息。 公共卫生相关性：肺动脉高压的发生会大大恶化许多肺部疾病患者的预后，例如肺部疾病。慢性阻塞性气道疾病，导致右心肥大和衰竭。该项目将在分子和细胞水平上阐明几个重要的 TRP 阳离子通道在慢性缺氧中 [Ca2+]i、血管舒缩张力和血管重塑的改变中的作用。拟议实验产生的信息可能有助于开发肺动脉高压的新疗法。