Calpain Activates Intracellular TGF-beta1 in Pulmonary Hypertension

描述（由申请人提供）：肺动脉高压（PAH）是一种严重的进行性疾病，其关键特征是肺血管重构，与细胞外基质（包括胶原）的积累、血管细胞增殖、内侧和外膜增厚、闭塞的新生内膜和复杂的丛状病变相关，导致毛细血管前动脉闭塞和肺动脉压持续升高。PDGF， EGF， VEGF和TGF？1 .参与肺血管重构过程。我们最近首次报道，在缺氧诱导的肺动脉高压中，calpain的整体敲除可阻止肺血管重构，calpain抑制剂MDL28170可阻止单芥碱诱导的肺动脉高压的进展。Calpain是一个钙依赖性非溶酶体中性半胱氨酸内肽酶家族，在哺乳动物细胞（包括肺血管细胞）中通过有限的底物蛋白水解起作用。Calpain是PDGF、EGF和VEGF的下游信号转导分子，介导PDGF和EGF诱导的肺动脉平滑肌细胞（PASMCs）的胶原合成和增殖，以及VEGF诱导的肺动脉内皮细胞（PAECs）的血管生成。我们最近发现钙蛋白酶裂解并激活TGF？1和胞内TGF？信号通路存在于pasmc中。为了在动物模型中验证calpain在肺血管重构中的作用，我们将利用肺动脉高压突破计划（PHBI）提供的人体肺组织，验证calpain激活细胞内TGF？1与IPAH相关的肺血管重构有关。为了验证这一假设，我们提出了一种多学科方法，重点关注以下具体目标：#1是确定calpain抑制是否阻止或减弱特发性肺动脉高压（IPAH）患者PASMCs和PAECs的胶原合成和增殖；#2是确定calpain是否激活细胞内TGF？IPAH患者的PASMCs和PAECs中有1。肺血管细胞中钙蛋白酶调节胶原合成和增殖的证据可能会导致新的药理学策略的发展，将钙蛋白酶靶向肺动脉高压相关的肺血管重构。

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a severe and progressive disease, a key feature of which is pulmonary vascular remodeling that is associated with accumulation of extracellular matrix, including collagen, and vascular cell proliferation, medial and adventitial thickening, occlusive neointima, and complex plexiform lesions, leading to obliteration of precapillary pulmonary arteries and sustained elevation of pulmonary arterial pressure. PDGF, EGF, VEGF, and TGF?1 participate in the process of pulmonary vascular remodeling. We recently reported for the first time that global knockout of calpain prevents pulmonary vascular remodeling in hypoxia-induced pulmonary hypertension and that the calpain inhibitor MDL28170 prevents the progression of established pulmonary hypertension induced by monocrotaline. Calpain is a family of calcium-dependent non-lysosomal neutral cysteine endopeptidases that act via limited proteolysis of substrate proteins in mammalian cells including pulmonary vascular cells. Calpain is the downstream signal transduction molecule of PDGF, EGF and VEGF, and mediates PDGF- and EGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells (PASMCs) and VEGF-induced angiogenesis of pulmonary artery endothelial cells (PAECs). We have recently found that calpain cleaves and activates TGF?1 and that an intracrine TGF? signal pathway exists in PASMCs. To validate the role of calpain in pulmonary vascular remodeling in animal models, we will take advantage of the human lung tissues provided by the Pulmonary Hypertension Breakthrough Initiative (PHBI) and test our novel hypothesis that calpain activates intracellular TGF?1 in pulmonary vascular remodeling associated with IPAH. To test this hypothesis, we propose a multidisciplinary approach focusing on the following specific aims: #1 is to determine whether calpain inhibition prevents or attenuates collagen synthesis and proliferation of PASMCs and PAECs from patients with idiopathic pulmonary arterial hypertension (IPAH); #2 is to determine whether calpain activates intracellular TGF?1 in PASMCs and PAECs from patients with IPAH. Proof of regulation of collagen synthesis and proliferation by calpain in pulmonary vascular cells may lead to development of new pharmacologic strategies that will target calpain in pulmonary vascular remodeling associated with pulmonary hypertension. PUBLIC HEALTH RELEVANCE: We recently reported that global calpain knockout prevents pulmonary vascular remodeling in hypoxia- induced pulmonary hypertension and the calpain inhibitor MDL28170 prevents the progression of established pulmonary hypertension induced by monocrotaline. This proposal is to study a novel hypothesis that calpain activates intracellular TGF?1 in idiopathic pulmonary arterial hypertension. The contribution of the proposed research to the field of pulmonary hypertension is expected to be leading to development of new pharmacologic strategies that will target calpain in pulmonary vascular remodeling associated with pulmonary hypertension. Successful completion of this project will help provide a new method for the prevention and treatment of pulmonary hypertension.