Epidermal Growth Factor Receptor Signaling in Fibrotic Skin Disease

项目摘要/摘要 纤维化是大多数人类慢性炎症性疾病的常见最终结果，据估计 造成世界上几乎一半的死亡1。它可由硬皮病等自身免疫性疾病引起， 移植物抗宿主病干细胞移植后，与肥胖相关的慢性炎症性疾病 和糖尿病以及遗传性遗传疾病。纤维化几乎可以影响到任何器官，包括皮肤， 肺、肾、肝、心脏和血管。硬皮病和移植物抗宿主病最常影响 皮肤和皮肤受累的程度与较高的死亡率和内脏功能障碍2，3， 暗示了共同的潜在机制。我们之前在这些疾病中发现了表皮的激活 成纤维细胞上的生长因子受体(EGFR)通过其免疫细胞衍生的配基表观调节素。这项建议旨在 进一步阐明我们在了解EGFR信号如何推动皮肤纤维化方面的主要差距。特别是， 目前尚不清楚EGFR激活下游的哪些信号通路对不同阶段的纤维化至关重要 以及这些靶点如何与其他与纤维化相关的途径相互作用。 在这个项目中，我们研究了成纤维细胞中慢性EGFR激活所产生的细胞信号 周细胞及其与调节干扰素依赖所必需的转录因子STAT1的相互作用 基因表达。在我们的第一个目标中，我们将表征成纤维细胞和周细胞中EGFR激活的影响。 使用Tet-On表达系统。该模型系统将允许对EGFR进行时间和细胞类型的控制 活体内激活。我们将分析哪些EGFR通路被激活并对皮肤的发育起作用 纤维化及其对免疫系统的影响。在第二个目标中，我们将研究相关的细胞类型 利用骨髓嵌合体和STAT1在纤维化的发展中需要哪种STAT1信号 条件基因敲除小鼠。我们将研究EGFR和STAT1信号是否相互依赖并利用 发现蛋白质相互作用和修饰的蛋白质组学技术。这些目标加在一起，将提供更好的 深入了解纤维性皮肤病的发病机制，使人们更广泛地理解纤维化是一种生物学现象 过程，并帮助开发可能对患者生活产生重大影响的新治疗方法。

PROJECT SUMMARY/ABSTRACT Fibrosis is a common final outcome of most human chronic inflammatory diseases and has been estimated to contribute to almost half of all deaths in the world 1. It can result from autoimmune diseases such as scleroderma, after stem cell transplant in graft-vs-host disease, from chronic inflammatory conditions associated with obesity and diabetes and through inherited genetic disorders. Fibrosis can affect virtually any organ including the skin, lungs, kidneys, liver, heart and blood vessels. Scleroderma and graft-vs-host disease most commonly affect the skin and the degree of skin involvement is associated with higher mortality and internal organ dysfunction 2,3, suggesting common underlying mechanisms. We previously identified in these diseases activation of epidermal growth factor receptor (EGFR) on fibroblasts by its immune cell derived ligand epiregulin. This proposal aims to further elucidate the major gaps in our knowledge of how EGFR signaling drives fibrosis in the skin. In particular, it is unclear what signaling pathways downstream of EGFR activation are critical to different phases of fibrosis and how these targets cross-talk with other fibrosis-associated pathways. In this project, we examine the cellular signals that result from chronic EGFR activation in fibroblasts and pericytes and their cross-talk with STAT1, an essential transcription factor for regulating interferon-dependent gene expression. In our first aim, we will characterize the effects of EGFR activation in fibroblasts and pericytes using a Tet-On expression system. This model system will allow temporal and cell-type control of EGFR activation in vivo. We will analyze what EGFR pathways are activated and required for development of skin fibrosis, and their effects on the immune system. In the second aim, we will examine the relevant cell types in which STAT1 signaling is required for development of fibrosis using bone marrow chimeras and STAT1 conditional knockout mice. We will investigate whether EGFR and STAT1 signaling are co-dependent and utilize proteomics techniques to discover protein interactions and modifications. Together, these aims will provide better insight into the pathogenesis of fibrotic skin disease, lead to a broader understanding of fibrosis as a biological process, and help develop new treatments that may substantially impact patients' lives.