Caveolins in the Pathogenesis of Idiopathic Pulmonary Fibrosis

描述（由申请人提供）： 拟议工作的长期目标是找出哪些新的致病机制参与特发性肺纤维化（IPF）的启动和进展，旨在发现可用作治疗工具的新分子靶点。顾名思义，IPF是一种发病机制不明的疾病。即使许多研究者强调肺泡内炎症是IPF的原因，抗炎和免疫调节剂治疗已被证明在限制疾病和改变疾病的自然病程方面效果甚微。目前认为，IPF是一种上皮-成纤维细胞疾病，由破坏正常肺泡上皮细胞稳态（发病）的不明内源性或环境刺激引起，随后是肺泡上皮的弥漫性激活（作为进展的途径），最后是异常上皮修复。肺泡上皮细胞活化的结果是产生有效的纤维化分子，如组织因子和纤溶酶原激活物抑制剂，可产生抗纤维蛋白溶解的肺泡内环境，促进纤维化反应增加，以及细胞因子，如肿瘤坏死因子和转化因子？(TGF?).研究表明，在辐射诱导的肺损伤后，以及在博莱霉素诱导的肺纤维化模型中，I型上皮细胞中的小窝蛋白1（cav-1）水平降低。更重要的是，cav-1基因敲除小鼠发生肺纤维化，可能是研究IPF的可靠模型。我的长期目标是研究小窝蛋白参与IPF的途径和分子机制。本申请将研究cav-2和TGF β-1的分布。受体（TGF？- R）在整个肺，将确定它们之间现有的时空关系，并将检查cav-2和TGF？信号通路，重点是Smads和TGF？-β的周转。R.为此，我将使用LTRC提供的人肺组织来找出TGF？R和cav-2在健康肺组织与IPF肺中的差异，我将分离人肺成纤维细胞以创建模型（具有低水平cav-2的成纤维细胞），该模型将允许将cav-2对IPF发病机制的贡献与报告的cav-1缺乏效应分开。该应用程序生成的数据将拓宽与IPF相关的致病机制的知识，并将提供更好地了解小窝蛋白参与肺部疾病所需的新信息。为了实现我们的目标，我们提出了以下建议：i）#1为了研究TGF？的表达并确定其亚细胞定位，R和Smads与IPF患者肺标本中的cav-2相关，以及ii）#2为了研究cav-2缺乏对TGF？信号传导和细胞外基质产生。 公共卫生相关性：该提案的目的是了解蛋白质caveolins（因其将不同分子粘合在一起的能力而被认可的结构蛋白）如何参与特发性肺纤维化（IPF）的开始和进展。IPF是一种独特且特异性的慢性肺病，病因不明，仅限于肺部，其特征为细胞增殖（尤其是成纤维细胞）和细胞外物质（主要是胶原蛋白样）积聚，最终导致肺结构的不可逆破坏。对相关机制的认识不足，沿着迄今为止使用的所有治疗方法都失败了，这是进行更多研究的充分理由，这些研究旨在整理出相关因素，并找到有效的新疗法。最近的研究发现，在IPF患者中，小窝蛋白的水平较低，并指出它们参与了疾病的开始。在IPF患者中报告的小窝蛋白水平的降低可以通过使用小窝蛋白的细胞穿透片段（首先由Lisanti的小组描述为小窝蛋白-1）作为治疗剂来校正，这可能代表用于治疗该疾病的一类新药。然而，基于小窝蛋白的药物的使用还需要清楚地描述小窝蛋白在疾病发展中的作用。因此，我们提出这项建议，旨在探索小窝蛋白的作用及其与疾病发生和进展的另一种重要分子转化生长因子在IPF发生和进展中的相互关系。因此，对于公众健康来说，没有什么比了解这种毁灭性疾病的原因更重要了，这将使真实的疗法能够控制并可能逆转它。

DESCRIPTION (provided by applicant): Long-term objectives of the proposed work are to find out what new pathogenic mechanisms are involved in initiation and progression of idiopathic lung fibrosis (IPF) with the intention to discover new molecular targets that can be used as therapeutic tools. As the name suggests, IPF is a disorder with an enigmatic pathogenesis. Even if many investigators have emphasized intraalveolar inflammation as a cause of IPF, anti-inflammatory and immune-modulator therapies have proved to be only minimal effective in limiting the illnesses and in modifying the natural course of the disease. Currently it is assumed that IPF is an epithelial- fibroblastic disease caused by unidentified endogenous or environmental stimuli that disrupt the normal alveolar epithelial cells homeostasis (the onset), followed-on by the diffuse activation of the alveolar epithelium (as a gateway for progression) and finally by aberrant epithelial repair. An outcome of activated alveolar epithelium is the production of potent fibrogenic molecules as tissue factor and plasminogen activator inhibitors that may generate an anti-fibrinolytic intraalveolar environment that facilitate an increased fibrotic response, and cytokines such as tumor necrosis factor and transforming factor ? (TGF?). It was shown that the levels of caveolin 1 (cav-1) are decreased in type I epithelial cells after radiation-induced lung injury, as well as in a model of bleomicin induced pulmonary fibrosis. More than that, the cav-1 knockout mice develop lung fibrosis and may be a reliable model for studying IPF. My long-term goals are to study the pathways and the molecular mechanisms by which the caveolins are involved in IPF. The present application will study the distribution of cav-2 and TGF?-receptor (TGF?-R) throughout the lung, will identify the existing spatiotemporal relations between them and will examine the molecular interactions between cav-2 and the TGF? signaling pathways with a focus on Smads and the turnover of TGF?-R. To this intent I will use human lung tissue provided by LTRC to find out the differences between the distribution of TGF?-R and cav-2 in healthy lung tissue versus lungs with IPF, and I will isolate human lung fibroblasts to create a model (fibroblasts with low levels of cav-2) that will allow separating the contribution of cav-2, to the pathogenesis of IPF, from what was reported to be a cav-1 deficiency effect. The data generated by this application will broaden the knowledge related to the pathogenic mechanisms involved in IPF and will provide new information needed to better understand the participation of caveolins in pulmonary diseases. In order to achieve our goals we are proposing the following: i) #1 To investigate the expression and to determine the subcellular localization of TGF?-R and Smads in relation to cav-2 from lung specimens of IPF patients, and ii) #2 To investigate the functional consequences of cav-2 deficiency on TGF? signaling and extracellular matrix production in lung specimens of IPF patients. PUBLIC HEALTH RELEVANCE: The aim of this proposal is to understand how the proteins caveolins (structural proteins recognized for their ability to glue together different molecules) are involved in the beginning and progression of Idiopathic Pulmonary Fibrosis (IPF). IPF is a distinct and specific form of chronic lung disease of unknown cause, limited to the lungs, and characterized by cellular proliferation (especially the fibroblast) and accumulation of extracellular material (mostly collagen like), that finally leads to irreversible destruction of lung architecture. The lack of knowledge of the mechanisms involved, along with the failure of all therapies used to date, are good reasons for more research oriented toward sorting out the factors involved and for finding new therapies that work. Recent work found out that in patients with IPF the levels of caveolins are lower and pointed to their involvement in starting the disease. The reduction in caveolin levels reported in IPF patients could be corrected by using cell penetrating fragments of caveolins (described first by Lisanti's group for caveolin-1) as therapeutic agents, which could represent a new class of drugs for the treatment of the disease. However, the usage of caveolin-based drugs awaits a clear delineation of the role that caveolins play in the development of the disease. Thus, we are putting forward this proposal aimed to explore the role of the caveolins and their interrelations with another important molecule for the development and progression of the disease, the transforming growth factor in the initiation and progression of IPF. Therefore nothing could be more important, for the public health than the understanding of the causes of such a devastating disease that will allow the development of real therapies able to control and may be to reverse it. (End of Abstract)