Tissue stiffness promotes pro-fibrotic metabolic dysregulation in lung fibrosis

项目总结/摘要 特发性肺纤维化（IPF）是一种进行性肺瘢痕形成疾病， 比肺癌短。目前的治疗减缓了一些患者的疾病进展，但不能治愈。IPF 和其它形式的间质性肺病的特征在于过量细胞外基质的积累 (ECM)，导致肺结构的破坏，无法进行气体交换，并最终 死亡我们发表了开创性的工作，即IPF患者肺部乳酸水平异常高， TGFβ驱动成纤维细胞在培养中产生过量的乳酸。乳酸盐反过来降低局部pH值， 激活潜在的TGFβ，导致促纤维化前馈回路，驱动纤维化。我们，以及其他 实验室已经发表了对ECM和ECM修饰酶的促纤维化性质的研究。 简而言之，TGFβ驱动成纤维细胞和肌成纤维细胞过度沉积ECM蛋白，并增加ECM蛋白的表达。 ECM的交联，硬化ECM。组织硬化是纤维化病症的标志， 被标记为纤维化的结果。现在，我们认识到，纤维化肺的高硬度直接诱导 肌成纤维细胞分化和促纤维化基因表达，至少部分通过激活潜伏的TGFβ， 包括整联蛋白和其他细胞表面蛋白的机械力。这就产生了第二种促纤维化的饲料 前向环，其中刚性微环境中的成纤维细胞被驱动朝向纤维化表型， 微环境的硬度。代谢失调和组织僵硬的重要性， 肺纤维化已被孤立地研究，但这两个关键途径之间的潜在联系， 没有被研究过。这两种途径之间的相互联系可能有助于解释为什么单一疗法 针对单一通路的药物只取得了有限的成功。在这里，我们将首次调查， 机械应力途径和促进纤维化的代谢失调途径 是相互联系的，生物力学应力驱使正常的肺成纤维细胞向促纤维化表型发展， 部分通过驱动代谢变化导致乳酸盐过量产生和TGFβ活化。我们的整体 一种假说认为，组织硬度的改变增强了乳酸代谢的失调， 肌成纤维细胞分化和肺纤维化，以及基质 交联和失调的乳酸代谢代表了一种新的治疗策略， 一种毁灭性的疾病我们将评估几种现有的和新的治疗方法， 预防或逆转肺细胞和肺纤维化临床前小鼠模型中的纤维化变化， 确定干预机械应力和代谢途径是否可以减缓或阻止疾病进展。

PROJECT SUMMARY/ABSTRACT Idiopathic Pulmonary Fibrosis (IPF) is a progressive scarring disease of the lung with a median survival rate shorter than lung cancer. Current treatments slow disease progression in some patients but are not a cure. IPF and other forms of interstitial lung disease are characterized by an accumulation of excess extracellular matrix (ECM), contributing to the destruction of lung architecture, inability to perform gas exchange, and eventually death. We published pioneering work that IPF patients have abnormally high levels of lactate in their lungs, and that TGFβ drives fibroblasts to produce excess lactate in culture. Lactate in turn decreases the local pH, which activates latent TGFβ resulting in a pro-fibrotic feed-forward loop, driving fibrosis. We, as well as other laboratories have published research into the pro-fibrotic properties of ECM and ECM-modifying enzymes. Briefly, TGFβ drives excess deposition of ECM proteins by fibroblasts and myofibroblasts, and increases crosslinking of the ECM, stiffening the ECM. Tissue stiffening is a hallmark of fibrotic disorders and has been marked as an outcome of fibrosis. Now, we recognize that high stiffnesses of the fibrotic lung directly induces myofibroblast differentiation and pro-fibrotic gene expression, at least partly by activating latent TGFβ via mechanical forces involving integrins and other cell surface proteins. This creates a second pro-fibrotic feed- forward loop where fibroblasts in a stiff microenvironment are driven toward a fibrotic phenotype that increases the stiffness of the microenvironment. The importance of metabolic dysregulation and tissue stiffness in pulmonary fibrosis have been studied in isolation, but the potential links between these two key pathways have not been studied. The interconnections between these two pathways may help to explain why monotherapies that target single pathways have shown only limited success. Here, we will investigate for the first time, the proposition that the mechanical stress pathways, and metabolic dysregulation pathways that promote fibrosis are interconnected, and that biomechanical stress drives normal lung fibroblasts toward a pro-fibrotic phenotype in part by driving metabolic changes resulting in excess production of lactate and activation of TGFβ . Our overall hypothesis is that altered tissue stiffness enhances dysregulation of lactate metabolism and contributes to myofibroblast differentiation and pulmonary fibrosis, and that combinatorial pharmacologic inhibition of matrix crosslinking and dysregulated lactate metabolism represents a novel therapeutic strategy to restore homeostasis in an otherwise devastating disease. We will evaluate several existing and novel therapeutic approaches to slow, prevent or reverse fibrotic changes in lung cells and in a preclinical mouse model of pulmonary fibrosis, to determine if interfering in mechanical stress and metabolic pathways can slow or halt disease progression.