Caveolins in the Pathogenesis of Idiopathic Pulmonary Fibrosis

描述(由申请人提供)： 这项拟议工作的长期目标是找出特发性肺纤维化(IPF)的发生和发展涉及哪些新的致病机制，以期发现可用作治疗工具的新的分子靶点。顾名思义，IPF是一种发病机制不明的疾病。尽管许多研究人员强调肺泡内炎症是IPF的原因之一，但事实证明，抗炎和免疫调节剂疗法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是一种由不明原因的内源性或环境刺激引起的肺泡上皮细胞动态平衡的疾病(发病时)，继而肺泡上皮的弥漫性激活(作为进展的通道)，最后是异常的上皮修复。肺泡上皮激活的一个结果是产生强大的纤维化分子，如组织因子和纤溶酶原激活物抑制物，可能产生抗纤溶的肺泡内环境，促进纤维化反应的增加，以及细胞因子，如肿瘤坏死因子和转化因子？(转化生长因子？)在放射性肺损伤和博莱米星肺纤维化模型中，I型上皮细胞小窝蛋白1(Cav-1)水平均明显降低。更重要的是，Cav-1基因敲除小鼠出现肺纤维化，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。本应用将研究Cav-2和转化生长因子受体(TGF？-R)在肺组织中的分布，确定它们之间存在的时空关系，并将研究Cav-2和转化生长因子受体(TGF？R)之间的分子相互作用。Smads和转化生长因子？-R的信号通路为此，我将使用LTRC提供的人肺组织来找出转化生长因子受体和Cav-2在健康肺组织和IPF肺组织中的分布差异，并分离人肺成纤维细胞以建立一个模型(低水平Cav-2的成纤维细胞)，从而将Cav-2在IPF发病机制中的作用与已报道的Cav-1缺乏效应分开。这一应用产生的数据将拓宽与IPF所涉及的致病机制相关的知识，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。为了达到我们的目标，我们提出了如下建议：1)研究转化生长因子受体和Smads在特发性肺纤维化患者肺组织中的表达和亚细胞定位；2)研究转化生长因子受体和Smads在肺纤维化患者肺组织中的表达和定位，以及2)研究转化生长因子受体2缺乏对转化生长因子受体的影响。特发性肺纤维化患者肺组织中信号和细胞外基质的产生。公共卫生相关性：这项建议的目的是了解小窝蛋白(因其粘合不同分子的能力而被公认的结构蛋白)如何参与特发性肺纤维化(IPF)的发生和发展。特发性肺纤维化是一种病因不明的慢性肺部疾病，局限于肺部，以细胞增殖(尤其是成纤维细胞)和细胞外物质(主要是胶原样)积聚为特征，最终导致肺结构不可逆转的破坏。对相关机制缺乏了解，加上迄今使用的所有疗法都失败了，这些都是进行更多研究的充分理由，这些研究旨在找出相关因素，并寻找有效的新疗法。最近的研究发现，在IPF患者中，小窝蛋白水平较低，这表明他们参与了疾病的开始。IPF患者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(由利桑蒂的小组首先为小窝蛋白-1描述)作为治疗剂来纠正，这可能代表一类治疗这种疾病的新药物。然而，基于小窝蛋白的药物的使用还有待于清楚地描述小窝蛋白在疾病发展中所起的作用。因此，我们提出这一建议，旨在探讨小窝蛋白的作用及其与疾病发生发展的另一个重要分子-转化生长因子在IPF发生和发展中的相互关系。因此，对于公共卫生来说，没有什么比了解这种毁灭性疾病的原因更重要的了，这种疾病将使能够控制并可能扭转这种疾病的真正疗法的发展。(摘要结束)

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)