MATRIX-DEGRADING PROTEINASES AND HEPATIC FIBROSIS

上皮下纤维化是肝损伤的一种严重形式，通常 与肝细胞功能明显受损相关。 我们 最近的研究表明，这代表了病理变化， 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聚糖。 后者 通常是上皮基底膜的成分。 我们 本建议的重点是机制， 病理过程开始了。 我们假设早期的 阶段是由局部介导的正常基质的分解 精细蛋白酶（胶原酶以及 攻击层粘连蛋白或蛋白聚糖）。 拟议的研究将 通过确定的肝实质检查蛋白酶的产生 和单个非实质细胞群在原发性 文化 分泌的蛋白酶的特征在于 它们的底物特异性抑制剂敏感性、分子大小和 通过激活间充质细胞的试剂（例如 佛波酯）。 将来自正常肝脏的细胞与 那些来自实验性纤维化肝脏的。 最后，影响 蛋白酶，以这种方式定义，对结构和生物学 将检查模型基底膜的性质。 的 调查结果预计将为启动 病理性肝纤维化的细胞和分子水平。

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.