Mechanobiology of Lung Fibrosis

项目摘要 肺纤维化是一种进行性的、最终致命的疾病，在这种疾病中，正在进行的细胞外基质(ECM) 这种基质的沉积和反馈生化和生物力学信号促进疾病 进步。我们已发表的和初步的数据表明，YAP和TAZ，转录效应因子 Hippo通路是IPF中成纤维细胞活化的关键调节因子，并控制ECM的沉积和 成纤维细胞使其变硬。然而，YAP和TAZ位于多条途径的下游，在 多种肺细胞类型，使靶向治疗的努力复杂化。因此，我们在这里重点介绍 开发成纤维细胞靶向抑制YAP/TAZ的方法。具体地说，我们已经确定了gpr 通过G-αS偶联的多巴胺D1受体作为成纤维细胞选择性途径的激动剂 停用YAP和TAZ。我们的体外和体内初步数据表明，药物刺激 不仅减弱成纤维细胞的活化，而且在功能上逆转成纤维细胞的状态，从基质沉积到 基质降解和逆转基质硬化。这些反应取决于对YAP/TAZ的抑制，因为 它们在表达具有构成活性的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一过性抑制，并稳定减少 在IPF受试者的肺中。因此，我们假设中心假设多巴胺信号正常 促进肺损伤后纤维化的消退，在IPF中消失，并可选择性地被DRD1激动剂靶向 逆转实验性肺纤维化。我们建议在三个具体目标上检验这一假设，结合 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体内分析内源性多巴胺对实验性纤维化的影响 从药理上讲，产量会减少，或者外源增加。拟议的研究将共同勾勒出 成纤维细胞从促纤维化到纤维化的一种新的受体介导机制 解决状态，在持久的纤维化模型中测试外源性靶向这一途径的治疗效果， 并探索这一途径的内源性活性是否正常地保护和解决进行性 纤维化，并在人类疾病中消失。

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.