同型半胱氨酸对人脐静脉内皮细胞表达ICAM-2及与树突状细胞粘附的影响

Effect of homocysteine on expression of intercellular adhesion molecule-2 and adhesion of dendritic cells to cultured human umbilical vein endothelial cells

目的探讨同型半胱氨酸(Hcy)对人脐静脉内皮细胞(HUVECs)分泌和表达细胞间粘附分子-2(I-CAM-2)以及内皮细胞与树突状细胞(DC)粘附的影响。方法在人脐静脉内皮细胞培养基中加入浓度为0.5mmolHL的Hcy作用不同时间,以及加入不同浓度的Hcy作用24h。用ELISA法检测内皮细胞培养基中HU-VECs分泌ICAM-2的蛋白含量,用Westernblot法检测HUVECs表达ICAM-2的蛋白含量,用分子探针标记的DC与HUVECs共孵育,共聚焦显微镜下计数粘附于HUVECs的DC数量,以检测Hcy对HUVECs与DC粘附的影响。结果用0.5mmolHLHcy干预后,HUVECs分泌ICAM-2蛋白在12h开始高于空白组(P<0.05),24h和48h均增加显著(均P<0.01);而ICAM-2蛋白的表达在6h开始高于空白组(P<0.05),24h达峰值(P<0.01),48h下降显著,且与空白组相比无统计学差异。用不同浓度的Hcy干预24h后,ICAM-2蛋白的分泌和表达及HUVECs与DC粘附均呈剂量依赖性增加,当Hcy浓度高于0.5mmolHL时增加更显著。结论Hcy能刺激HUVECs分泌和表达ICAM-2蛋白,从而促进HUVECs与DC的粘附,这可能是其诱导动脉粥样硬化早期形成的重要机制之一。

Objective To investigate the effect of homocysteine （Hcy） on expression and secretion of intercellular adhesion molecule-2 （ICAM-2） and dendritic cells （DC） adhesion to cultured human umbilical vein endothelial cells （HUVECs）. Methods HUVECs were exposed to Hcy in different concentration for 24h or at the concentration of 0.5 mmol/L for different time length. Enzyme-linked immunosorbent assay （ELISA） was performed to measure the secretion of ICAM-2 protein. Western blot was used to detect the expression of ICAM-2 protein. CellTracker labeled DC were coincubated＇ with HUVECs, the adherent DC were quantified by using confocal microscope. Results After exposure of the HUVECs to Hcy at the concentration of 0.5 mmol/L, the secretion of ICAM-2 was higher than that of the control group at 12 h （P〈0.05）, and that was more significant at 24 h and 48 h （P〈0.01）. The expression of ICAM-2 was higher than that of the control group at 6 h（P〈0.05） , and it reached the peak at 24 h （P〈0.01）. After exposure to different concentrations of HCY for 24 h the expression and secretion of ICAM-2 and the adherent DC increased in a dose-dependent manner （P〈0.01）. Conclusion Homocysteine can induce ICAM-2 expression and secretion in HUVECs, promote adhesion of DC to HUVECs, which may be associated with the pathogenesis of atherosclerosis.