Regulation of Mechano-Induced TGFb1 Activation and Myofibroblast Differentiation

描述(申请人提供)：特发性肺纤维化(IPF)是一种进行性致死性肺部疾病，以持续的肌纤维细胞分化和过度合成细胞外基质(ECM)为特征。肌成纤维细胞产生更多的收缩力量，通过跨膜整合素从细胞骨架传递到周围的细胞外基质。这导致了细胞外基质结合的潜在转化生长因子(TGF)-(1)的激活，这是最有效的促纤维化细胞因子。证据表明，这种机械诱导的潜在的转化生长因子-1的激活对于维持肌成纤维细胞的分化是必不可少的。了解机械诱导的转化生长因子-1激活和肌成纤维细胞分化的调控机制具有重要的科学意义和临床意义。THY-1是一种糖基磷脂酰肌醇(GPI)连接的细胞表面蛋白，已被证明可以防止肺肌成纤维细胞的分化和纤维化。Thy-1抗纤维化作用的机制尚不清楚。目前的初步数据显示，表达Thy-1的肺成纤维细胞对成纤维细胞的收缩反应增加，潜伏的转化生长因子-1激活和转化生长因子-1依赖的α-平滑肌肌动蛋白(SMA)的表达增加，而表达Thy-1的肺成纤维细胞不能。在本研究中，我们假设Thy-1调节机械诱导的潜伏的转化生长因子-1的激活和肺肌成纤维细胞的分化。这些研究的具体目的是：1)确定Thy-1是否调节成纤维细胞收缩力量的形成和力诱导的、依赖于转化生长因子(1)的肌成纤维细胞分化。我们将采用一种可变形的硅胶基质起皱试验来测量成纤维细胞的收缩能力。我们将建立一种装置，通过使用从Thy-1缺失和野生型小鼠分离的肺实质条，在组织水平上测试Thy-1的作用。2)确定Thy-1-整合素相互作用是否阻断成纤维细胞的机械转导，消除机械力诱导的潜在的转化生长因子-1的激活和肺肌成纤维细胞的分化。我们将产生一个突变的Thy-1，其中Thy-1与整合素的结合能力被破坏，以检验我们的假设。我们的研究旨在了解机械诱导的潜伏性转化生长因子-1激活和肺肌成纤维细胞分化调节的分子机制。目的是确定分子靶点，通过阻断肺成纤维细胞分化来开发治疗IPF的新的治疗措施。公共卫生相关性：特发性肺纤维化(IPF)是一种进行性、致死性纤维性肺部疾病，没有有效的治疗方法。建议的研究将探索肺纤维化发病机制的分子机制。我们的目标是为IPF治疗开发新的治疗干预措施。

DESCRIPTION (provided by applicant): Idiopathic Pulmonary Fibrosis (IPF) is a progressive lethal lung disease characterized by persistent myofibroblast differentiation and excessive synthesis of extracellular matrix (ECM). Myofibroblasts produce increased contraction forces that are transmitted from the cytoskeleton to the surrounding ECM by transmembrane integrins. This results in activation of the ECM-bound latent transforming growth factor (TGF)-(1, the most potent fibrogenic cytokine. Evidence suggests that such mechano-induced latent TGF-(1 activation is essential for maintaining myofibroblast differentiation. Understanding of the mechanisms involved in regulation of mechano-induced TGF-(1 activation and myofibroblast differentiation is of both scientific significance and clinical interest. Thy-1, a glycosyl phosphatidylinositol (GPI)-linked cell surface protein, has been shown to prevent lung myofibroblast differentiation and fibrosis. The mechanisms underlying Thy-1 anti-fibrotic effect are not clear. Preliminary data now show that lung fibroblasts expressing Thy-1 respond to fibroblast contraction with increased latent TGF-(1 activation and TGF-(1-dependent alpha-smooth muscle actin ((SMA) expression, whereas lung fibroblasts lacking Thy-1 expression do not. In this study, we hypothesize that Thy-1 regulates mechano-induced latent TGF-(1 activation and lung myofibroblast differentiation. Specific Aims in the proposed studies are: 1) To determine whether Thy-1 regulates fibroblast contraction force formation and force-induced, TGF-(1-dependent myofibroblast differentiation. We will employ a deformable silicone substrate wrinkling assay to measure fibroblast contractility. We will build a device to test the role of Thy-1 at the tissue level by using lung parenchymal strips isolated from Thy-1 null and wild-type mice. 2) To determine whether Thy-1-integrin interactions interrupt fibroblast mechanotransduction, abrogating mechanical force-induced latent TGF-(1 activation and lung myofibroblast differentiation. We will generate a mutated Thy-1 in which the capability of Thy-1 binding to integrins is disrupted to test our hypothesis. Our studies are aimed at understanding the molecular mechanisms involved in regulation of mechano-induced latent TGF-(1 activation and lung myofibroblast differentiation. The goal is to identify molecular targets for developing novel therapeutic interventions for treatment of IPF by blocking lung myofibroblast differentiation. PUBLIC HEALTH RELEVANCE: Idiopathic pulmonary fibrosis (IPF) is a progressive, lethal fibrotic lung disease with no effective therapies. The proposed studies will explore the molecular mechanisms involved in the pathogenesis of lung fibrosis. Our goal is to develop novel therapeutic interventions for IPF treatment.