Role of fibrotic extracellular matrix in generating the IPF Fibroblast

描述(申请人提供)：特发性肺纤维化(IPF)是一种致命的纤维性肺部疾病，每年导致40,000美国人死亡，全球超过100万人死亡。在IPF中，肺泡间充质细胞数量的持续扩张和改变导致病理性肌成纤维细胞的产生，这些细胞介导气体交换表面的进行性瘢痕形成，导致窒息死亡。来自IPF患者肺的成纤维细胞具有不同于正常肺成纤维细胞的表型特征。在模型生物中，肺间质成纤维细胞改变了整合素的表达，过度增殖，产生大量的胶原，表达大量的�平滑肌肉肌动蛋白(�MA)，并形成纤维化病变。我们最近发表了病理性肺间充质祖细胞(MPC)是IPF成纤维细胞的起源细胞；IPF细胞外基质(ECM)重新编程成纤维细胞的基因表达，以建立一个正反馈循环，从翻译上激活ECM基因及其同源细胞表面受体。在这个项目中，我们总结了我们的范式转换数据。首先，我们证明了IPF肺MPC--但不是对照肺MPC--产生的后代具有IPF成纤维细胞的体外和体内特征。接下来，我们发现当原代肺成纤维细胞(IPF或对照)与去细胞的肺ECM(IPF或对照)相互作用时：i)ECM来源主要决定基因表达；ii)IPF肺ECM翻译激活ECM基因及其同源整合素受体基因；iii)IPF肺ECM，但不对照ECM，减少成纤维细胞miR29的表达-一种有效的ECM和增殖基因的负调节因子-创建正反馈环，为疾病持续发展提供分子机制。基于此，我们假设去细胞的IPF肺ECM将引导人肺MPC向IPF表型分化；并通过表观遗传调节miR29的表达来稳定该表型，以创建一个正反馈环路，驱动控制IPF成纤维细胞标志的基因。我们提出了两个特定的目标来阐明其分子机制。特异目的1：IPF成纤维细胞的起源--研究MPC在IPF肺ECM上获得IPF表型标志的机制。具体目标2：疾病进展-剖析IPF ECM驱动的正反馈环的分子和细胞机制，该环增加整合素和ECM基因的表达，并抑制它们的负调控因子miR29。如果我们实现我们的目标，我们的工作将揭示控制IPF成纤维细胞及其病理性ECM的发生、维持和增殖的机制。这些信息是开发针对推动IPF的ECM-间充质细胞相互作用的治疗方法的基础。

DESCRIPTION (provided by applicant): Idiopathic Pulmonary Fibrosis (IPF) is a lethal fibrotic lung disorder that kills 40,000 Americans each year and over 1 million persons worldwide. In IPF, relentless expansion and alteration of the alveolar mesenchymal cell population leads to production of diseased myofibroblasts that mediate progressive scarring of the gas exchange surface resulting in death by asphyxiation. Fibroblasts derived from the lungs of IPF patients have phenotypic hallmarks that distinguish them from their normal counterparts. IPF fibroblasts have altered integrin expression, are hyperproliferative, produce increased amounts of collagen, express increased amounts of �mooth muscle actin (�MA) and form fibrotic lesions in model organisms. We recently published that pathological lung mesenchymal progenitor cells (MPCs) are a cell-of-origin for the IPF fibroblast; and that IPF extracellular matrix (ECM) reprograms fibroblast gene expression to establish a positive feedback loop that translationally activates ECM genes and their cognate cell surface receptors. In this project we summarize our paradigm-shifting data. First, we show that IPF lungs MPCs - but not control lung MPCs - generate progeny with the in vitro and in vivo hallmarks of IPF fibroblasts. Next, we show that when primary lung fibroblasts (IPF or control) interact with decellularized lung ECM (IPF or control): i) the ECM source predominantly dictates gene expression; ii) IPF lung ECM translationally activates ECM genes and genes encoding their cognate integrin receptors; and iii) IPF lung ECM, but not control ECM, decreases fibroblast expression of miR29 - a potent negative regulator of ECM and proliferation genes - creating a positive feedback loop that provides a molecular mechanism for relentless disease progression. Based on this, we hypothesize that decellularized IPF lung ECM will direct human lung MPC differentiation towards the IPF phenotype; and stabilize that phenotype by epigenetic regulation of miR29 expression to create a positive feedback loop driving genes governing IPF fibroblast hallmarks. We propose 2 specific aims to elucidate the molecular mechanisms. Specific Aim 1: Genesis of the IPF fibroblast - Characterize the mechanisms by which MPCs acquire IPF phenotypic hallmarks on IPF lung ECM. Specific Aim 2: Disease Progression - Dissect the molecular and cellular mechanisms of the IPF ECM-driven positive feedback loop that increases integrin and ECM gene expression and suppresses their negative regulator, miR29. If we achieve our aims, our work will unveil mechanisms governing the genesis, maintenance and propagation of the IPF fibroblast and its pathological ECM. This information is foundational for developing therapies that target those ECM - mesenchymal cell interactions that drive IPF.