Research for the medical treatment of rheumatoid arthritis by endogenous inhibitor of aggrecanase

骨胶蛋白对关节软骨的不良承载和减震连接处起着重要作用。在退化性关节疾病中，如类风湿关节炎（RA）和骨关节炎（OA），细胞外基质的损失导致关节软骨的破坏。聚集蛋白水解是导致细胞外基质分解的早期事件之一。基质金属蛋白酶是软骨退行性变的关键酶。最近的研究表明，aggrecanase-1和aggrecanase-2是ADAMTS（一种具有血栓反应蛋白基元的崩解素和金属蛋白酶）家族的成员，这些酶被认为在RA或OA中软骨聚集蛋白的磨损中起关键作用。基质金属蛋白酶-3组织抑制剂（TIMP-3）是一种强效的聚合酶-1和-2抑制剂，但TIMP-3是否是唯一的聚合酶抑制剂尚不清楚。因此，鉴定一种特定的内源性聚聚糖酶抑制剂对于考虑治疗退化性关节疾病的新药物至关重要。本研究的目的是鉴定内源性的聚合酶-1抑制剂，并表征其与内源性抑制剂的相互作用机制。我们以人聚合酶-1催化结构域为诱饵进行酵母双杂交筛选，并将含有该诱饵质粒的EGY48酵母菌株与人肝脏cDNA文库质粒转化。我们确定α -1-抗胰蛋白酶和α -1-抗凝乳胰蛋白酶是血浆丝氨酸蛋白酶抑制剂的成员。

Aggrecan is greatly responsible for bad-bearing and shock-absorbing junction of the joint cartilage. In degradative articular diseases such as rheumatoid arthritis(RA) and osteoarthritis(OA), loss of extracellular matrices occurs resulting in the destruction of joint cartilage. Aggrecan proteolysis is one of the early events leading to the breakdown of the extracellular matrix. Matrix metalloproteinases have been reported to be the key enzymes in cartilage degeneration. Recent studies show that aggrecanase-1 and aggrecanase-2 are members of the ADAMTS(a disintegrin and metalloproteinase with thrombospondin motifs) family, and these enzymes are considered to play a pivotal role in the abrasion of cartilage aggrecan in RA or OA. Tissue inhibitor of matrix metalloproteinase-3(TIMP-3) is a potent inhibitor of aggrecanase-1 and -2, but whether TIMP-3 is the only inhibitor of aggrecanases remains unknown. The identification of a specific endogenous aggrecanase inhibitor therefore would be of critical importance in considering new medication for degradative joint diseases. The aims of the current study were to identify the endogenous inhibitor of aggrecanase-1 and to characterize the mechanism of interaction between aggrecanase-1 and its endogenous inhibitor We performed the yeast two-hybrid screen using the catalytic domain of human aggrecanase-1 as a bait, and an EGY48 yeast strain containing the bait plasmid was transformed with a human liver cDNA library plasmid. We identified alpha-1-antitrypsin and alpha-1-antichymotrypsin, members of plasma serine proteinase inhibitors, as preys.