Regulation of Mechano-Induced TGFb1 Activation and Myofibroblast Differentiation

描述（由申请人提供）：特发性肺纤维化（IPF）是一种进行性致死性肺病，其特征为持续性肌成纤维细胞分化和细胞外基质（ECM）过度合成。肌成纤维细胞产生增加的收缩力，该收缩力通过跨膜整合素从细胞骨架传递到周围的ECM。这导致ECM结合的潜伏性转化生长因子（TGF）-β 1（最有效的纤维化细胞因子）的活化。有证据表明，这种机械诱导的潜伏性TGF-β 1活化对于维持肌成纤维细胞分化是必不可少的。了解机械力诱导的TGF-β 1活化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，已被证明可防止肺肌成纤维细胞分化和纤维化。Thy-1抗纤维化作用的机制尚不清楚。初步数据显示，表达Thy-1的肺成纤维细胞对成纤维细胞收缩的反应是潜在的TGF-β 1激活和TGF-β 1依赖的α-平滑肌肌动蛋白（SMA）表达增加，而缺乏Thy-1表达的肺成纤维细胞则没有。在这项研究中，我们假设Thy-1调节机械诱导的潜在TGF-β 1活化和肺肌成纤维细胞分化。本研究的具体目的是：1）确定Thy-1是否调节成纤维细胞收缩力的形成和力诱导的TGF-β 1依赖性肌成纤维细胞分化。我们将采用可变形的硅胶基质收缩试验来测量成纤维细胞的收缩性。我们将建立一个装置，通过使用从Thy-1 null和野生型小鼠分离的肺实质条来测试Thy-1在组织水平上的作用。2)确定Thy-1-整合素相互作用是否中断成纤维细胞机械转导，消除机械力诱导的潜在TGF-β 1活化和肺肌成纤维细胞分化。我们将产生突变的Thy-1，其中Thy-1与整联蛋白结合的能力被破坏，以测试我们的假设。我们的研究旨在了解机械诱导的潜在TGF-β 1活化和肺成肌纤维细胞分化的分子机制。目的是确定分子靶点，以开发通过阻断肺肌成纤维细胞分化治疗IPF的新型治疗干预措施。公共卫生相关性：特发性肺纤维化（IPF）是一种进行性、致死性纤维化肺病，目前尚无有效治疗方法。这些研究将探讨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.