Ito H, Chimata M, Oka M, Suzuki Y, Hamada N, Fujimaki M, Oda K, Fujisawa K, Teramoto T, Nakamura K
First Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan.
Nephron. 1995;69(3):305-10. doi: 10.1159/000188475.
The expression of low density lipoprotein (LDL) receptors by cultured rat mesangial cells was demonstrated using immunohistochemical and biochemical methods. Using a mouse monoclonal anti-human LDL receptor antibody, the immunofluorescence technique was applied to cultured mesangial cells and showed granular staining. Immunoblotting analysis of the membrane fraction of cultured mesangial cells showed a single band with a protein of approximately 130,000 molecular weight. In addition, [125I]LDL binding and the uptake of [125I]LDL by cultured mesangial cells were studied. Binding and uptake both reached an equilibrium after about 30 min of incubation. A 50% reduction in [125I]LDL (20 micrograms protein/ml) binding and uptake occurred when unlabelled LDL was added to cultures at 20-40 micrograms protein/ml. Addition of high density lipoprotein without apoE to the culture medium did not induce competitive inhibition of [125I]LDL binding and uptake by mesangial cells. These findings suggest that cultured mesangial cells have the capacity to express an LDL receptor that regulates the cellular uptake of LDL.
采用免疫组化和生化方法证实了培养的大鼠系膜细胞可表达低密度脂蛋白（LDL）受体。使用小鼠抗人LDL受体单克隆抗体，将免疫荧光技术应用于培养的系膜细胞，结果显示呈颗粒状染色。对培养的系膜细胞膜组分进行免疫印迹分析，结果显示有一条分子量约为130,000的蛋白条带。此外，还研究了培养的系膜细胞对[125I]LDL的结合及摄取情况。孵育约30分钟后，结合和摄取均达到平衡。当向培养物中加入20 - 40微克蛋白/毫升的未标记LDL时，[125I]LDL（20微克蛋白/毫升）的结合和摄取减少了50%。向培养基中添加不含载脂蛋白E的高密度脂蛋白，并未诱导系膜细胞对[125I]LDL的结合和摄取产生竞争性抑制。这些发现表明，培养的系膜细胞具有表达LDL受体的能力，该受体可调节细胞对LDL的摄取。
