Mechanobiology of Lung Fibrosis

项目摘要 肺纤维化是一种进行性且最终致命的疾病，其中持续的细胞外基质（ECM） 来自该基质的沉积和反馈生物化学和生物力学信号促进疾病 进展我们发表的和初步的数据表明，雅普和TAZ，转录效应子， Hippo通路是IPF中成纤维细胞活化的关键调节剂，并控制ECM沉积和 由成纤维细胞硬化。然而，雅普和TAZ是多个途径的下游，并且在以下方面发挥关键作用： 多种肺细胞类型，使靶向治疗变得复杂。因此，我们在此重点关注 开发成纤维细胞靶向的雅普/TAZ抑制方法。具体来说，我们已经确定了GPCR 通过Gα s-偶联多巴胺D1受体（DRD 1）作为成纤维细胞选择性途径的激动作用， 吉雅普和塔兹。我们在体外和体内的初步数据表明，药理刺激， DRD 1不仅减弱成纤维细胞的活化，而且在功能上将其状态从基质沉积逆转为 基质降解和基质硬化的逆转。这些反应依赖于对雅普/TAZ的抑制， 它们在表达组成型活性TAZ突变蛋白的细胞中丢失。已发表的报告表明， 内源性多巴胺能信号存在于正常肺中;我们的初步数据表明， 多巴胺合成途径在小鼠实验性纤维化过程中被短暂抑制， IPF受试者的肺部。因此，我们否定了多巴胺信号正常传递的中心假设， 促进肺损伤后纤维化消退，在IPF中丢失，可通过DRD 1激动剂选择性靶向 逆转实验性肺纤维化我们建议在三个具体目标中检验这一假设， 肺上皮细胞多巴胺合成的体外分析及多巴胺能信号对肺的影响 成纤维细胞功能，以及在体内分析小鼠实验性纤维化，其中内源性多巴胺 生产损失，或外源性增加。拟议的研究将共同描绘 成纤维细胞从促进纤维化转变为纤维化的新型受体介导机制 解决状态，在持久的纤维化模型中测试该途径的外源性靶向的治疗功效， 并探索该通路的内源性活性是否正常地保护和解决进行性 纤维化，并在人类疾病中丢失。

Project Summary Pulmonary fibrosis is a progressive and ultimately fatal disease in which ongoing extracellular matrix (ECM) deposition and feedback biochemical and biomechanical signaling from this matrix promotes disease progression. Our published and preliminary data demonstrate that YAP and TAZ, transcriptional effectors of the Hippo pathway, are pivotal regulators of fibroblast activation in IPF, and control both ECM deposition and stiffening by fibroblasts. However, YAP and TAZ are downstream of multiple pathways, and play critical roles in multiple lung cell types, complicating efforts to target them therapeutically. Therefore we focus here on developing a fibroblast-targeted approach to YAP/TAZ inhibition. Specifically, we have identified GPCR agonism via Gαs-coupled dopamine D1 Receptor (DRD1) as a fibroblast selective approach through which to inactivate YAP and TAZ. Our in vitro and in vivo preliminary data demonstrate that pharmacologic stimulation of DRD1 not only attenuates fibroblast activation, but functionally reverses their state from matrix depositing to matrix degradation and reversal of matrix stiffening. These responses depend on inhibition of YAP/TAZ, as they are lost in cells expressing constitutively active TAZ mutant protein. Published reports suggest that endogenous dopaminergic signaling is present in the normal lung; our preliminary data demonstrate that the dopamine synthetic pathway is transiently depressed during experimental fibrosis in mice, and stably reduced in the lungs of subjects with IPF. Thus, we posit the central hypothesis that dopamine signaling normally promotes fibrosis resolution after lung injury, is lost in IPF, and can be selectively targeted by DRD1 agonism to reverse experimental lung fibrosis. We propose to test this hypothesis in three specific aims, combining in vitro analysis of dopamine synthesis by lung epithelial cells and dopaminergic signaling effects on lung fibroblast function, as well as in vivo analysis of experimental fibrosis in mice in which endogenous dopamine production is lost, or exogenously augmented pharmacologically. Together the proposed studies will delineate a novel receptor mediated mechanism by which fibroblast can be switched from fibrosis promoting to fibrosis resolving states, test the therapeutic efficacy of exogenous targeting of this pathway in durable fibrosis models, and explore whether the endogenous activity of this pathway normally protects from and resolves progressive fibrosis, and is lost in human disease.