Hayashi K, Horikoshi S, Osada S, Shofuda K, Shirato I, Tomino Y
Division of Nephrology, Department of Medicine, Juntendo University School of Medicine, Tokyo, Japan.
J Pathol. 2000 Jul;191(3):299-305. doi: 10.1002/1096-9896(2000)9999:9999<::AID-PATH637>3.0.CO;2-L.
Membrane-type matrix metalloproteinases (MT-MMPs) have been shown to activate pro-MMP-2 on the cell surface and are suggested to be key enzymes in tissue remodelling under various physiological and pathological conditions. To investigate the role of MT-MMP in progressive renal injury, the gene expression and enzymatic activity of MT-MMP were examined in crescentic glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody in WKY rats. Isolated glomeruli were subjected to RNA and protein extraction 0, 1, 3, 7, 14, and 28 days after intravenous injection of rabbit anti-GBM antibody. Semiquantitative RT-PCR analysis revealed that among the three members of the MT-MMP family, mRNA expression of MT2-MMP remained unchanged and that of MT3-MMP was not observed in glomeruli during the development of nephritis. However, MT1-MMP gene expression increased from day 3 and reached maximum levels at day 7 (5.5+/-0.7-fold increase over day 0), closely associated with macrophage accumulation, crescent formation, and increased proteinuria. Gelatin zymography showed that the active from of MMP-2 emerged from day 7 and remained during the experimental period accompanied by increased proMMP-2, while no active form of MMP-2 was found in control rats. Using an antisense cRNA probe, intense signals of MT1-MMP mRNA were observed mostly in cells within the crescent and in some cells in the mesangial areas. Most of these cells were ED-1-positive macrophages, based on immunostaining of sequential sections. These results suggested that in the MT-MMP family, MT1-MMP was induced in infiltrating macrophages during the development of crescentic glomerulonephritis and possibly contributed to pathological degradation of glomerular extracellular matrices through the activation of proMMP-2.
膜型基质金属蛋白酶（MT - MMPs）已被证明可在细胞表面激活前MMP - 2，并被认为是各种生理和病理条件下组织重塑中的关键酶。为了研究MT - MMP在进行性肾损伤中的作用，我们检测了WKY大鼠抗肾小球基底膜（GBM）抗体诱导的新月体性肾小球肾炎中MT - MMP的基因表达和酶活性。在静脉注射兔抗GBM抗体后的0、1、3、7、14和28天，分离肾小球进行RNA和蛋白质提取。半定量RT - PCR分析显示，在MT - MMP家族的三个成员中，MT2 - MMP的mRNA表达保持不变，而在肾炎发展过程中未在肾小球中观察到MT3 - MMP的表达。然而，MT1 - MMP基因表达从第3天开始增加，并在第7天达到最高水平（比第0天增加5.5±0.7倍），这与巨噬细胞积聚、新月体形成和蛋白尿增加密切相关。明胶酶谱分析表明，MMP - 2的活性形式从第7天开始出现，并在实验期间持续存在，同时前MMP - 2增加，而在对照大鼠中未发现MMP - 2的活性形式。使用反义cRNA探针，在新月体内的细胞和系膜区的一些细胞中大多观察到MT1 - MMP mRNA的强烈信号。根据连续切片的免疫染色，这些细胞大多数是ED - 1阳性巨噬细胞。这些结果表明，在MT - MMP家族中，MT1 - MMP在新月体性肾小球肾炎发展过程中在浸润的巨噬细胞中被诱导，并且可能通过激活前MMP - 2导致肾小球细胞外基质的病理性降解。
