Stylianou E, Nie M, Ueda A, Zhao L
Division of Renal and Inflammatory Disease, School of Medical and Surgical Sciences, University of Nottingham, England, United Kingdom.
Kidney Int. 1999 Sep;56(3):873-82. doi: 10.1046/j.1523-1755.1999.00640.x.
The chemokine monocyte chemoattractant protein-1 (MCP-1) is secreted by human glomerular mesangial cells in response to interleukin-1 (IL-1) and has a central role in amplifying the inflammatory response during glomerulonephritis. However, the mechanism by which IL-1 regulates its transcription is not understood. Specific members of the nuclear factor kappaB/rel (NF-kappaB) proteins may regulate MCP-1 expression in a stimulus- and tissue-specific manner.
Electrophoretic mobility shift assays and Western blot analysis characterized the members of the NF-kappaB family that bound the two NF-kappaB sites of the MCP-1 enhancer (A1 and A2) in vitro. Trans-activation of the MCP-1 gene was investigated by transfer of the MCP-1 enhancer DNA to mesangial cells.
Primary human mesangial cells contained in addition to p50 (NF-kappaB1) and p65 (Rel A) NF-kappaB proteins, the oncoprotein c-rel, and Rel B, but not p52 (NF-kappaB2). IL-1 induced c-rel to form a complex with p65, which bound the MCP-1 A2 site but not the A1 or IL-6 NF-kappaB sites in vitro. IL-1 up-regulated transfected MCP-1 enhancer activity. Cotransfer of the MCP-1 enhancer together with individual members of the NF-kappaB family showed that the heterodimer c-relp65 or (p65)2 can selectively trans-activate the MCP-1 gene via its A1 and A2 sites in mesangial cells.
This study demonstrates for the first time that the c-rel oncoprotein can enhance MCP-1 transcription in mesangial cells and suggests that it may have an important role in amplifying gene expression in the inflamed glomerulus.
趋化因子单核细胞趋化蛋白-1（MCP-1）由人肾小球系膜细胞响应白细胞介素-1（IL-1）分泌，在肾小球肾炎炎症反应放大过程中起核心作用。然而，IL-1调节其转录的机制尚不清楚。核因子κB/rel（NF-κB）蛋白的特定成员可能以刺激和组织特异性方式调节MCP-1表达。
电泳迁移率变动分析和蛋白质印迹分析鉴定了在体外与MCP-1增强子的两个NF-κB位点（A1和A2）结合的NF-κB家族成员。通过将MCP-1增强子DNA转染至系膜细胞研究MCP-1基因的反式激活。
原代人系膜细胞除了含有p50（NF-κB1）和p65（Rel A）NF-κB蛋白外，还含有癌蛋白c-rel和Rel B，但不含有p52（NF-κB2）。IL-1诱导c-rel与p65形成复合物，该复合物在体外结合MCP-1 A2位点，但不结合A1或IL-6 NF-κB位点。IL-1上调转染的MCP-1增强子活性。MCP-1增强子与NF-κB家族单个成员共转染表明，异二聚体c-relp65或（p65）2可通过其在系膜细胞中的A1和A2位点选择性反式激活MCP-1基因。
本研究首次证明癌蛋白c-rel可增强系膜细胞中MCP-1转录，并提示其可能在炎症肾小球基因表达放大中起重要作用。
