Role of fibrotic extracellular matrix in generating the IPF Fibroblast

描述（由申请人提供）：特发性肺纤维化（IPF）是一种致命的纤维化肺部疾病，每年导致40，000名美国人死亡，全球超过100万人死亡。在IPF中，肺泡间充质细胞群的持续扩张和改变导致产生病变的肌成纤维细胞，其介导气体交换表面的进行性瘢痕形成，导致窒息死亡。来源于IPF患者肺的成纤维细胞具有将其与其正常对应物区分开的表型特征。IPF成纤维细胞具有改变的整合素表达，是过度增殖的，产生增加量的胶原蛋白，表达增加量的平滑肌肌动蛋白（SMA），并在模型生物体中形成纤维化病变。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;并且IPF细胞外基质（ECM）重新编程成纤维细胞基因表达以建立正向反馈回路，其间接激活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变数据。首先，我们表明，IPF肺MPC-而不是对照肺MPC-产生具有IPF成纤维细胞的体外和体内标志的后代。接下来，我们表明，当原代肺成纤维细胞（IPF或对照）与脱细胞肺ECM相互作用（IPF或对照）：i）ECM来源主要支配基因表达; ii）IPF肺ECM抑制性激活ECM基因和编码其同源整联蛋白受体的基因;和iii）IPF肺ECM，而不是对照ECM，降低成纤维细胞miR 29的表达-一种ECM和增殖基因的有效负调节因子-产生正反馈环，为无情的疾病进展提供分子机制。基于此，我们假设去细胞化的IPF肺ECM将引导人肺MPC向IPF表型分化;并通过miR 29表达的表观遗传调节来稳定该表型，以产生正反馈环，驱动管理IPF成纤维细胞标志的基因。我们提出了2个具体的目标来阐明分子机制。具体目标1：IPF成纤维细胞的发生-表征MPC在IPF肺ECM上获得IPF表型标志的机制。具体目标二：疾病进展-剖析IPF ECM驱动的正反馈环的分子和细胞机制，该正反馈环增加整合素和ECM基因表达并抑制其负调节因子miR 29。如果我们实现了我们的目标，我们的工作将揭示IPF成纤维细胞及其病理性ECM的发生、维持和增殖的机制。该信息是开发靶向驱动IPF的ECM -间充质细胞相互作用的疗法的基础。

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.