CELLULAR PATHOPHYSIOLOGY OF HEPATIC FIBROSIS

拟议的研究旨在定义细胞和分子 肝脏病理性纤维化的潜在事件。它建立在最近的 已经确定了肝脏内特定细胞类型的研究 产生细胞外基质。数据指向肝脏脂肪细胞 (也称为Ito或脂肪储存细胞)是 细胞外基质蛋白，特别是在肝脏损伤中，如 炎症，在这种情况下，这些细胞会随着增殖和 增加了基质成分的合成。因为他们的位置在 Disse空间及其对细胞外生物学功能的影响 迪斯空间中的矩阵很可能很重要。的数组的 这些细胞在纤维化损伤中表现出的变化，目前尚不清楚 是病理基质改变的生物效应的中心。 已被分配细胞结合角色的蛋白质包括层粘连蛋白和 纤维连接蛋白；因此，它们在体内合成或构象的变化 细胞外基质可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。在肝脏损伤方面， 脂肪细胞可以产生不同形式的这些蛋白质。拟议中的工作 将表征脂肪细胞合成层粘连蛋白的特性，并特别关注 蛋白质中存在假定的细胞结合区；它将 同样地，通过量化个体来评估纤维连接蛋白的表达 与损伤有关的异构体(在mRNA水平) 肝脏以外的其他组织的反应。第三个目标是隔离 利用一种新的亲和矩阵从正常大鼠肝细胞层粘连蛋白受体 其中保存了层粘连蛋白的生物活性。该项目将 提供有关层粘连蛋白和纤维连接蛋白合成的首次详细数据 肝脂肪细胞，在正常和激活状态下，在培养和 在活体内。通过在分子水平上表征与以下各项相关的关键事件 对于纤维化，它将对预防或治疗做出重要贡献 治疗这种常见的、使人虚弱的肝病表现。

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.