Takahara T, Furui K, Yata Y, Jin B, Zhang L P, Nambu S, Sato H, Seiki M, Watanabe A
Third Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Japan.
Hepatology. 1997 Dec;26(6):1521-9. doi: 10.1002/hep.510260620.
We have previously reported increased expression of matrix metalloproteinase-2 (MMP-2) using a rat model of liver fibrosis. However we did not clarify how the precursor of MMP-2 (proMMP-2) was activated. Therefore, we used human liver specimens with chronic hepatitis (CH) and liver cirrhosis (LC) to examine expression of membrane-type-1-MMP (MT1-MMP), which has recently been determined to activate proMMP-2. Northern hybridization studies showed a 5.4- and 1.4-fold increase in MMP-2 expression in CH and LC, respectively, as compared with normal liver. MT1-MMP gene expression simultaneously increased 4.0- and 1.4-fold in CH and LC, respectively. In situ hybridization using 35S-cRNA probes of MMP-2 and MT1-MMP showed prominent silver granules in elongated cells found in the lobules, periportal areas, and fibrous septa of CH and LC samples. These elongated cells expressed alpha-smooth muscle actin by immunohistochemistry. Immunoelectron microscopic examination localized MMP-2 and MT1-MMP to the rough endoplasmic reticulum of stellate cells located in the lobules and periportal areas, or to fibroblasts in the fibrous septa, suggesting that MMP-2 and MT1-MMP were produced by these cells. In addition, cytoplasmic and membranous immunodeposits of both MMPs were found in endothelial cells, Kupffer cells, capillary endothelial cells, and lymphocytes, indicating that activation of proMMP-2 occurs locally. Increased expression of MMP-2 and MT1-MMP was detected in CH and LC, while dual over-expression was found in stellate cells and fibroblasts, possibly resulting in the increase of active MMP-2 in and around these cells. These findings suggest that activated MMP-2 may remodel liver parenchyma during the process of liver fibrosis.
我们之前曾报道，在肝纤维化大鼠模型中基质金属蛋白酶-2（MMP-2）的表达增加。然而，我们并未阐明MMP-2的前体（proMMP-2）是如何被激活的。因此，我们使用慢性肝炎（CH）和肝硬化（LC）患者的肝脏标本，来检测膜型-1-MMP（MT1-MMP）的表达，最近已确定其可激活proMMP-2。Northern杂交研究显示，与正常肝脏相比，CH和LC中MMP-2的表达分别增加了5.4倍和1.4倍。MT1-MMP基因表达在CH和LC中同时分别增加了4.0倍和1.4倍。使用MMP-2和MT1-MMP的35S-cRNA探针进行原位杂交显示，在CH和LC样本的小叶、汇管区和纤维间隔中发现的细长细胞中有明显的银颗粒。通过免疫组织化学检测，这些细长细胞表达α-平滑肌肌动蛋白。免疫电镜检查将MMP-2和MT1-MMP定位到位于小叶和汇管区的星状细胞的粗面内质网，或纤维间隔中的成纤维细胞，表明MMP-2和MT1-MMP是由这些细胞产生的。此外，在内皮细胞、库普弗细胞、毛细血管内皮细胞和淋巴细胞中发现了两种MMP的胞质和膜免疫沉积物，表明proMMP-2的激活发生在局部。在CH和LC中检测到MMP-2和MT1-MMP的表达增加，而在星状细胞和成纤维细胞中发现了双重过表达，这可能导致这些细胞及其周围活性MMP-2的增加。这些发现表明，激活的MMP-2可能在肝纤维化过程中重塑肝实质。
