IGFBP-5 and Hsp70 in Extracellular Matrix Homeostasis and Fibrosis

描述(申请人提供)：间质性肺疾病(ILD)包括一组130多种疾病，其特征是肺部的疤痕形成或纤维化。一些ILDS的原因是已知的，包括那些与结缔组织疾病有关的疾病，如系统性硬化症(SSC，或硬皮病)。然而，尽管进行了密集的研究，但导致纤维化开始和持续的基本机制仍然难以捉摸。这项建议勾勒出详细的5年科学和职业发展计划，旨在促进申请人成功过渡到独立调查员的角色，并为她成为基质生物学和纤维化肺部疾病的世界级研究人员奠定坚实的基础。导师实验室的研究表明，特发性肺纤维化患者的硬皮病成纤维细胞和纤维化肺组织中胰岛素样生长因子结合蛋白5(IGFBP-5)的表达增加。此外，IGFBP-5在体外和体内的过度表达会导致细胞外基质(ECM)的异常产生，这是纤维化疾病的一个标志。IGFBP-5可诱导主要的细胞外基质蛋白纤维连接蛋白和I型胶原的表达。此外，体内肺组织和SSc相关肺纤维化患者的原代成纤维细胞中Hsp70热休克蛋白的表达均减少，以响应lGFBP-5的过表达。我们假设IGFBP-5通过Hsp70依赖的途径增加基质结构蛋白的产生，从而破坏ECM的动态平衡，导致纤维化。本研究的具体目的是：(1)明确lGFBP-5介导的细胞外基质失衡的机制；(2)研究IGFBP-5对Hsp70的调控作用；(3)研究Hsp70和热休克转录因子在细胞外基质沉积调控中的作用。原代培养的小鼠和人肺成纤维细胞的生化和遗传学研究将阐明LGFBP-5‘S调控热休克蛋白70和细胞外基质的信号通路和转录因子，以及热休克蛋白和转录因子调节细胞外基质的产生。补充体内工作将在IGFBP-5在肺中过度表达的小鼠模型中进行。总之，这些研究将提供对IGFBP-5促纤维化级联和热休克反应在ECM沉积中的作用的机械性见解，从而加深对导致纤维化的细胞外基质稳态失调的理解。相关性(参见说明)：间质性肺疾病(ILDS)导致显著的发病率和死亡率，并且没有有效的药物治疗来逆转纤维化。拟议的研究不仅将有助于确定lGFBP-5和Hsp70如何影响细胞外基质平衡，而且还将为肺内纤维增生性疾病的机制提供更好的见解，并为开发新的诊断和治疗策略奠定基础。(摘要结束)

DESCRIPTION (provided by applicant): Interstitial lung disease (ILD) comprises a group of more than 130 disorders characterized by scarring, or fibrosis, of the lungs. The causes of some of the ILDs are known, including those associated with connective tissue diseases such as systemic sclerosis (SSc, or scleroderma). Despite intense study, however, the basic mechanisms responsible for the initiation and perpetuation of fibrosis remain elusive. This proposal outlines a detailed 5-year scientific and career development plan designed to facilitate the applicant's successful transition to the role of independent investigator and provide a solid foundation for her to become a world-class researcher in matrix biology and fibrotic lung disease. Work performed in the mentor's laboratory has demonstrated increased expression of insulin-like growth factor binding protein 5 (IGFBP-5) in scleroderma fibroblasts and fibrotic lung tissue from patients with idiopathic pulmonary fibrosis. Furthermore, over-expression of IGFBP-5 in vitro and in vivo results in aberrant extracellular matrix (ECM) production, a hallmark of fibrotic disease. IGFBP-5 induces expression of the major extracellular matrix proteins fibronectin and collagen I. Additionally, there is reduced expression of the Hsp70 heat shock protein both in vivo in lung tissue and primary fibroblasts from patients with SSc-associated pulmonary fibrosis and in vitro in response to lGFBP-5 over-expression. We hypothesize that IGFBP-5 increases production of matrix structural proteins through Hsp70-dependent pathways, thereby disrupting ECM homeostasis and resulting in fibrosis. The specific aims of this proposal are to (1) identify the mechanism of lGFBP-5 mediated ECM imbalance, (2) characterize the regulation of Hsp70 by IGFBP-5, and (3) characterize the role of Hsp70 and the heat shock transcription factors in the regulation of ECM deposition. Biochemical and genetic in vitro studies in primary mouse and human lung fibroblasts will elucidate signaling pathways and transcription factors involved in lGFBP-5's regulation of Hsp70 and the ECM, as well as in regulation of ECM production by heat shock proteins and transcription factors. Complementary in vivo work will be conducted in a mouse model of IGFBP-5 over-expression in the lung. In total, these studies will provide mechanistic insight into the IGFBP-5 pro-fibrotic cascade and the role of the heat shock response in ECM deposition, leading to an enhanced understanding of the derangements in extracellular matrix homeostasis that lead to fibrosis. RELEVANCE (See instructions): The interstitial lung diseases (ILDs) result in significant morbidity and mortality, and there are no effective medical therapies to reverse fibrosis. The proposed investigations will not only serve to define how lGFBP-5 and Hsp70 affect extracellular matrix balance, but will also provide better insight into the mechanisms of fibroproliferative diseases in the lung and serve as a foundation for the development of novel diagnostic and therapeutic strategies for the ILDs. (End of Abstract)