Evidence for secretion of cytosolic CuZn superoxide dismutase by hep G2 cells and human fibroblasts
Evidence for secretion of cytosolic CuZn superoxide dismutase by hep G2 cells and human fibroblasts
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DOI：
10.1016/1357-2725(96)00004-0
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发表时间：
1996-06-01
影响因子：
4
通讯作者：
Santangelo, F
中科院分区：
文献类型：
--
作者：
Mondola, P;Annella, T;Santangelo, F
迄今为止，细胞内 CuZn 超氧化物歧化酶的作用是细胞内氧自由基清除剂。然而，胞浆 CuZn 超氧化物歧化酶的其他功能已被假设。例如，CuZn超氧化物歧化酶与培养的大鼠肝细胞一起孵育可抑制3-羟基-3甲基戊二酰辅酶A还原酶，从而减少胆固醇合成。我们最近证明了铜锌超氧化物歧化酶表面膜受体的存在，表明可能存在自分泌或旁分泌活性。本研究的目的是探讨人肝癌和成纤维细胞系是否可以分泌胞质铜锌超氧化物歧化酶。人肝细胞癌 (Hep G2) 细胞和人成纤维细胞中的蛋白质采用 [S-35]-半胱氨酸进行生物合成标记；然后用兔多克隆抗人CuZn超氧化物歧化酶抗体对细胞裂解物和培养基进行免疫沉淀，并通过12%聚丙烯酰胺凝胶电泳分离。 Hep G2 细胞和人成纤维细胞均产生并分泌 CuZn 超氧化物歧化酶，其在细胞和培养基中可检测为单一蛋白带，其电泳迁移率与人红细胞 CuZn 超氧化物歧化酶相同。这些数据表明，CuZn超氧化物歧化酶（一种迄今为止被认为仅位于细胞内的酶）由至少两种细胞系分泌。这与 CuZn 超氧化物歧化酶的自分泌或旁分泌作用一致。 (C) 1996 爱思唯尔科学有限公司
The role so far ascribed to intracellular CuZn superoxide dismutase is that of an intracellular scavenger of oxygen radicals. However, other functions of cytosolic CuZn superoxide dismutase have been hypothesized. For example, CuZn superoxide dismutase incubated with rat hepatocyte cells in culture inhibits 3-hydroxy-3methylglutaryl CoA reductase, thereby reducing cholesterol synthesis. We recently demonstrated the presence of surface membrane receptors for CuZn superoxide dismutase, suggesting possible autocrine or paracrine activities. The aim of the present study was to investigate whether cytosolic CuZn superoxide dismutase can be secreted by human hepatocarcinoma and fibroblast cells lines. Proteins in human hepatocellular carcinoma (Hep G2) cells and human fibroblasts were biosynthetically labelled with [S-35]-cysteine; then cell lysates and media were immunoprecipitated with rabbit polyclonal anti-human CuZn superoxide dismutase antibodies and separated by 12% polyacrylamide gel electrophoresis. Both Hep G2 cells and human fibroblasts produce and secrete CuZn superoxide dismutase which was detectable in cells and medium as a single protein band with the same electrophoretic mobility as human erythrocyte CuZn superoxide dismutase. These data suggest that CuZn superoxide dismutase, an enzyme thus far considered to be located exclusively intracellularly is secreted by at least two cell lines. This is consistent with autocrine or paracrine roles for CuZn superoxide dismutase. (C) 1996 Elsevier Science Ltd