Li Shan, Zhu Wei-guo, Yan Hui, Fan Fang-yan, Sun Pei-yu, Zhu Jian-hua
Department of Cardiology, First Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou 310003, People's Republic of China.
Int Immunopharmacol. 2007 Sep;7(9):1241-50. doi: 10.1016/j.intimp.2007.05.009. Epub 2007 Jun 13.
Elevated plasma homocysteine (Hcy) is an independent risk factor for atherosclerosis, which is recognized as inflammatory and immune responses. The purpose of this study was to investigate the effect of Hcy on the interaction between dendritic cells (DCs) and endothelial cells (ECs) by upregulating the expression of DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN) in cultured DCs. The immunophenotype of Hcy-treated DCs was monitored by flow cytometry. Then, they were coincubated with cultured human umbilical vein endothelial cells, and adhesion of DCs to ECs, and migration of DCs through an endothelial monolayer growing on the insert of a transwell plate, were assessed using a confocal microscope and a multi-detection microplate reader. The expression of DC-SIGN on Hcy-stimulated DCs was assessed by Western blot and immunofluorescence staining. The presence of Hcy did not change the phenotype of immature and mature DCs. Hcy promoted adhesion of DCs to ECs and migration in a concentration-dependent fashion. This effect was inhibited by an anti-DC-SIGN monoclonal antibody. The expression of DC-SIGN on DCs was significantly upregulated by Hcy in a concentration-dependent manner. Taken together, our results show for the first time that Hcy can potentiate the adhesion of DCs to ECs and migration by upregulating the expression of DC-SIGN on DCs, suggesting a novel role of Hcy in the pathogenesis of human vascular disease.
血浆同型半胱氨酸（Hcy）水平升高是动脉粥样硬化的独立危险因素，动脉粥样硬化被认为与炎症和免疫反应有关。本研究旨在通过上调培养的树突状细胞（DC）中DC特异性细胞间黏附分子3结合非整合素（DC-SIGN）的表达，探讨Hcy对DC与内皮细胞（EC）相互作用的影响。采用流式细胞术监测Hcy处理的DC的免疫表型。然后，将它们与培养的人脐静脉内皮细胞共孵育，使用共聚焦显微镜和多功能微孔板读数仪评估DC与EC的黏附以及DC通过Transwell板小室上生长的内皮单层的迁移情况。通过蛋白质免疫印迹法和免疫荧光染色评估Hcy刺激的DC上DC-SIGN的表达。Hcy的存在并未改变未成熟和成熟DC的表型。Hcy以浓度依赖的方式促进DC与EC的黏附及迁移。这种作用被抗DC-SIGN单克隆抗体抑制。Hcy以浓度依赖的方式显著上调DC上DC-SIGN的表达。综上所述，我们的结果首次表明，Hcy可通过上调DC上DC-SIGN的表达来增强DC与EC的黏附及迁移，提示Hcy在人类血管疾病发病机制中的新作用。
