RESPONSE IN LUNG EXTRACELLULAR MATRIX TO ASBESTOS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 由于蒙大拿州利比的居民暴露在石棉污染的蛭石中，人们对石棉相关疾病(ARD)的关注有所加强。蚯蚓分布在全国200多个地点，疾病发展的潜伏期很长，这使得ARD成为一个持续的公共卫生问题。吸入石棉纤维会导致多种ARD，包括石棉肺、肺癌和间皮瘤。本研究将通过研究SPARC在这一过程中的作用来关注石棉引起的纤维化，因为我们发现几种类型的石棉纤维使小鼠肺中SPARC的表达增加。SPARC是一种基质细胞蛋白，通过调节生长因子活性参与调节细胞外基质(ECM)细胞间的相互作用。这些先前确定的功能使SPARC成为参与石棉肺的一个令人兴奋的候选者。本文提出的研究将阐明SPARC在石棉肺中的作用，特别是针对抑制SPARC表达如何调节细胞外基质的产生。该项目的目标是阐明母细胞蛋白SPARC参与调控细胞外基质沉积对青石棉和Libby闪石的响应。我们研究的中心假设是SPARC的表达是通过调节ECM的产生而在肺纤维化的发展中重要的一步。 为了验证这一假设，我们提出了以下目标：1)建立SPARC基因缺失和匹配的野生型(WT)小鼠暴露于生理盐水、Libby闪石和青石棉后SPARC和ECM蛋白的体内表达。这一目标的关键要素包括使用天生缺乏这种蛋白质的SPARC缺失小鼠以及RNA干扰(RNAi)作为一种机制来控制WT小鼠在纤维暴露后SPARC的表达。2)研究从SPARC基因缺失和配对的WT小鼠分离的原代肺成纤维细胞对生理盐水、Libby闪石和青石棉的反应。这一目标的关键要素包括分析细胞外基质蛋白以及接触闪石后基因表达的变化。 作为拟议研究的结果，我们希望更好地理解SPARC在肺纤维化发展中的作用，这是通过接触闪石后ECM的产生来衡量的。我们还将研究阻断SPARC表达作为减少纤维化反应的治疗措施的可能性。通过研究与纤维化发展有关的一个关键问题，该提案还将开始探讨使用RNA干扰来控制SPARC表达作为治疗肺纤维化疾病的可能性。由于数以千计的石棉接触者面临健康风险，这些研究的最终目标是为这些和其他类似的环境引起的肺部疾病确定新的治疗目标的发展方向。此外，这种潜在的治疗方法对包括IPF在内的所有形式的纤维化的治疗都有意义。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Attention to asbestos-related diseases (ARD) has intensified due to the exposure of Libby, MT residents to asbestos-contaminated vermiculite. Vermiculite distribution to 200+ sites nationwide and the long latent period for disease development make ARD a continuing public health issue. Exposures to asbestos fibers by inhalation cause multiple ARD including asbestosis, lung cancer and mesothelioma. This investigation will focus on asbestos-caused fibrosis by studying the role of SPARC in this process, since we found increased expression of SPARC in mouse lungs exposed to several types of asbestos fibers. SPARC is a matricellular protein involved in the regulation of extracellular matrix (ECM)cell interactions through modulation of growth factor activity. These previously identified functions make SPARC an exciting candidate for involvement in asbestosis. The investigations proposed here will elucidate the role of SPARC in asbestosis, specifically targeting how inhibition of SPARC expression can regulate ECM production. The goals of this project are to delineate the involvement of the matricellular protein SPARC in the regulation of ECM deposition in response to crocidolite and the Libby amphibole. The central hypothesis to be tested in our studies is that expression of SPARC is a significant step in the development of lung fibrosis through the modulation of ECM production. To test the hypothesis, we propose the following aims: 1) Establish the in vivo expression of SPARC and ECM proteins in Sparc-null and matched wild-type (WT) mice after exposure to saline, the Libby amphibole, and crocidolite asbestos. Key elements of this aim include the use of Sparc-null mice constitutively lacking the protein as well as RNA interference (RNAi) as a mechanism to control SPARC expression in WT mice after fiber exposure. 2) Characterize the response of primary lung fibroblast cultures isolated from Sparc-null and matched WT mice to saline, the Libby amphibole, and crocidolite asbestos. Key elements of this aim include analysis of ECM proteins as well as changes in gene expression after amphibole exposure. As a result of the proposed studies, we hope to achieve a better understanding of the role of SPARC in the development of lung fibrosis as measured by ECM production after amphibole exposure. We will also study the potential for blocking SPARC expression as a therapeutic measure to reduce the fibrotic response. By investigating a critical question concerning fibrosis development, this proposal will also begin to address the potential for using RNA interference to control SPARC expression as a treatment for fibrotic diseases of the lung. Because of the health risks faced by thousands of asbestos-exposed individuals, the ultimate goal of these studies is to identify a direction for the development of novel therapeutic targets for these and other similar environmentally-caused lung diseases. In addition, this potential therapy has implications for treatment of all forms of fibrosis, including IPF.