MATRIX-DEGRADING PROTEINASES AND HEPATIC FIBROSIS

内皮下纤维化是一种严重的肝损伤形式，通常 与肝细胞功能明显受损有关。我们的 最近的研究表明，这是一种病理改变。 包括IV型胶原的正常内皮下基质， 层粘连蛋白和硫酸乙酰肝素蛋白多糖。后者是 通常情况下，上皮基底膜的成分。我们的 本提案的重点是这样一种机制 病理过程被启动。我们假设早些时候 阶段是由局部中介的正态矩阵的分解 精制的蛋白酶(胶原酶以及 攻击层粘连蛋白或蛋白多糖)。拟议的研究将 用明确的肝实质检测蛋白水解酶 和个体非实质细胞群体在原代培养中 文化。分泌型蛋白水解酶的特征是 它们的底物特异性抑制剂的灵敏度、分子大小和 由激活间充质细胞的试剂(如 佛波酯)。来自正常肝脏的细胞将与 那些来自实验性肝纤维化的。最后，它的影响 以这种方式定义的蛋白酶，在结构和生物上 我们将测试一个模型基底膜的性能。这个 预计调查结果将为启动 细胞和分子水平的病理性肝纤维化。

Subendothelial fibrosis is a severe form of liver injury, often associated with markedly impaired hepatocellular function. Our recent studies suggest that this represents pathological alteration of the normal subendothelial matrix comprising type IV collagen, laminin and heparan sulfate proteoglycan. The latter are constituents of epithelial basement membranes generally. Our focus in the present proposal is the mechanism whereby this pathologic process is initiated. We hypothesize that an early stage is breakdown of the normal matrix mediated by locally elaborated proteinases (collagenases as well as enzymes that attack laminin or proteoglycan). The proposed studies will examine proteinase production by defined hepatic parenchymal and individual non-parenchymal cell populations in primary culture. Secreted proteinases will be characterized in terms of their substrate specificity inhibitor sensitivity, molecular size and modulation by agents that activate mesenchymal cells (such as phorbl esters). Cells from normal liver will be compared with those from experimentally fibrotic liver. Finally, the effect of proteinases, defined in this manner, on the structure and biological properties of a model basement membrane will be examined. The findings are expected to shed new light on the initiation of pathologic hepatic fibrosis at the cellular and molecular level.