Glucose-induced loss of glycosyl-phosphatidylinositol-anchored membrane regulators of complement activation (CD59, CD55) by in vitro cultured human umbilical vein endothelial cells
Glucose-induced loss of glycosyl-phosphatidylinositol-anchored membrane regulators of complement activation (CD59, CD55) by in vitro cultured human umbilical vein endothelial cells
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DOI：
10.1007/s001250051487
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发表时间：
2000-08-01
期刊：
影响因子：
8.2
通讯作者：
Triolo, G
中科院分区：
文献类型：
--
作者：
Accardo-Palumbo, A;Triolo, G;Triolo, G
目标/假设。这项研究探讨了葡萄糖浓度升高是否与补体激活分子的膜调节分子表达减少有关。同时还研究了高糖对血管内皮细胞膜攻击复合体沉积增加的影响。从脐带组织中分离内皮细胞，在葡萄糖浓度升高的情况下培养，用酶联免疫吸附试验和流式细胞仪检测CD46、CD55和CD59的表达，并用抗内皮细胞抗体和新鲜补体孵育内皮细胞，以评估膜攻击复合体的形成。高浓度葡萄糖以时间依赖和葡萄糖浓度依赖的方式抑制内皮细胞CD59和CD55的表达，但不影响CD46的表达。在高糖处理的细胞上清液中可见高浓度的可溶性CD59。细胞与钙通道阻滞剂(维拉帕米)共孵育可逆转高糖诱导的CD59表达下降。所有这些效应都不是渗透控制介质所能复制的。高浓度葡萄糖处理的细胞在抗内皮细胞抗体作用下更容易发生补体活化和膜攻击复合体的形成。我们推测，高血糖可能通过钙依赖的磷酸肌醇特异性磷脂酶C激活和随后调节GPI锚定蛋白的细胞壁表达而直接导致CD59和CD55分子的丢失。这种现象可以促进补体途径的激活，并可能在糖尿病血管内皮细胞功能障碍的病因学中发挥作用。
Aims/hypothesis. This study examines whether increased glucose concentrations are responsible for a decreased expression of membrane regulators of complement activation molecules. The effect of high glucose in determining an increase in membrane attack complex deposition on endothelial cells was also investigated.Methods. Endothelial cells were isolated from umbilical cord tissue, cultured in the presence of increased concentrations of glucose, and the expression of CD46, CD55, and CD59 was detected by ELISA (enzyme-linked immunosorbent assay) and by flow cytometry, Glucose-treated endothelial cells were also incubated with antiendothelial cell antibodies and fresh complement to assess the amount of membrane attack complex formation.Results. High concentrations of glucose decreased the expression of CD59 and CD55 by endothelial cells in a time-dependent and glucose concentration-dependent manner without affecting CD46 expression. High concentrations of soluble CD59 were found in the supernatants of cells treated with high glucose. The decrease in CD59 expression induced by high glucose concentrations was reversed by coincubation of cells with a calcium channel blocking agent (Verapamil). All of these effects were not reproduced by osmotic control media. Cells treated with concentrations of high glucose were more susceptible to complement activation and membrane attack complex formation after exposure to antiendothelial cell antibodies.Conclusion/Interpretation. We speculate that hyperglycaemia could directly contribute to a loss of CD59 and CD55 molecules through a calcium-dependent phosphoinositol-specific phospholipase C activation and subsequent regulation of cell wall expression of GPI-anchored proteins. This phenomenon could facilitate the activation of a complement pathway and could play a part in the aetiology of endothelial dysfunction in diabetes.