CELLULAR PATHOPHYSIOLOGY OF HEPATIC FIBROSIS

拟议的研究是针对定义细胞和分子 肝脏病理性纤维化的潜在事件。它建立在最近的 研究表明肝脏内的特定细胞类型 产生细胞外基质。数据显示肝脂肪细胞 (also称为伊藤或脂肪储存细胞）作为主要来源， 细胞外基质蛋白，特别是在肝损伤中，如 炎症，其中这些细胞经历增殖活化， 增加基质成分的合成。由于其位于 Disse空间，它们对细胞外生物功能的影响 矩阵在空间的Disse可能是重要的。阵列的 这些细胞在纤维化损伤中表现出的变化，目前还不清楚 是病理基质改变生物学效应的核心。 已被分配细胞结合作用的蛋白质包括层粘连蛋白和层粘连蛋白。 纤连蛋白;因此，在它们的合成或构象内的变化， 细胞外基质可以直接影响细胞与基质的相互作用， 肝细胞表达肝脏特异性功能。在肝损伤中， 脂肪细胞可以产生这些蛋白质的变体形式。拟议工作 将描述层粘连蛋白合成的脂肪细胞，特别注意 蛋白质中存在假定的细胞结合区域;它将 类似地评价纤连蛋白表达，对个体进行定量 与损伤有关的亚型（mRNA水平） 除肝脏外的其他组织的反应。第三个目标是隔离 利用新型亲和基质从正常大鼠肝细胞中分离层粘连蛋白受体 其中层粘连蛋白的生物活性得以保留。该项目将 提供了关于层粘连蛋白和纤连蛋白合成的第一个详细数据， 正常和活化状态下的肝脂肪细胞，在培养物中， in vivo.通过在分子水平上表征与 纤维化，这将有助于重要的努力，在预防或 治疗这种普遍和衰弱的肝病表现。

The proposed research is directed at defining the cellular and molecular events underlying pathologic fibrosis in the liver. It builds on recent studies that have characterized the specific cell types within the liver that produce extracellular matrix. The data point to hepatic lipocytes (also known as Ito or fat-storing cells) as the major source of extracellular matrix proteins, particularly in liver injury, such as inflammation, where these cells undergo activation with proliferation and increased synthesis of matrix components. Because of their location in the Space of Disse, their impact on the biological function of extracellular matrix in the space of Disse is likely to be important. Of the array of changes exhibited by these cells in fibrosing injury, it is unclear which are central to the altered biologic effects of the pathologic matrix. Proteins that have been assigned cell-binding roles include laminin and fibronectin; thus, changes in their synthesis or conformation within the extracellular matrix could directly affect cell-matrix interaction and the expression of liver-specific functions by hepatocytes. In liver injury, lipocytes may produce variant forms of these proteins. The proposed work will characterize laminin synthesis by lipocytes with specific attention to the presence of putative cell-binding regions in the protein; it will similarly evaluate fibronectin expression, with quantitation of individual isoforms (at the mRNA level) that have been implicated in the injury response of tissues other than liver. A third aim is the isolation of laminin receptors from normal rat hepatocytes using a novel affinity matrix in which the biological activity of laminin is preserved. The project will provide the first detailed data on synthesis of laminin and fibronectin by hepatic lipocytes, in both the normal and activated state, in culture and in vivo. By characterizing at a molecular level key events associated with fibrosis, it will contribute importantly to efforts at prophylaxis or therapy for this prevalent and debilitating manifestation of liver disease.