The Effect Of Amlodipine On CD40 Expression In The Human Umbilical Vein Endothelial Cell Induced By The Oxidized Low Density Lipoprotein

BACGROUNDCD40/CD40L system is proven to be an important mediator in the regulation of Lymphocytes activation and the course of humoral immunity. Recent study has demonstrated that CD40/CD40L expressed on the endotheliocyte and played a critical role in the activation of proatherogenic pathways,the progression of atherosclerosis and the development of vulnerable plague.Our previous work show calcium channel block(CCB) has remarkable anti-atherosclerosis effect which is not completely dependent on the effect of reduce blood pressure. However, the mechanism is still unclear. So the aim of the present study is to probe into such details.Objective:To investigate the effects of amlodipine on the expression of CD40 in human umbilical vein endothelial cell by oxLDL and explore their mechanism, which would provide experimental base for suppresseing the development of atherosclerosis.Methods:1,Endothelial cells(HUVEC-12) were cultured and incubated with oxLDL at different concentrations(0-100μg/ml) for the same time(24h) and at the same concentration(50μg/ml) for different time course(0-24h). the expression of CD40 at both mRNA and protein levels were detected by RT-PCR and Western blotting respectively.2,Lectin-like oxLDL receptor-1(LOX-1) blocking agent(PIA) was used to observe the role of LOX-1 in the expression of CD40 in endotheliocytes induced by oxLDL. 3,Cultured endothelial cells were pretreated with amlodipine at different concentrations (0.1-10μmol/L) for 1h and then incubated with oxLDL at the same concentration(50μg/ml) for 24h. CD40 expressions were detected by RT-PCR ,immunocytochemistry and Western blotting respectively. LOX-1 mRNA expressions were also detected to observe the effect of amlodipine on LOX-1 gene expression induced by the oxidized low density lipoprotein.Results1,CD40 was slightly expressed in normal endotheliocyte but oxLDL induced a significant increase in the expression of CD40 in a dose-dependent manner within 0-50μg/ml for 24h and in a time-dependent manner within 0-24h, peaked at 50μg/ml for 24h.2,After pretreated HUVEC-12 cells with Polyinosinic acid (PIA) for 1 h, CD40 expression induced by oxLDL was obviously down-regulated. PIA had no effect on the basal expression of CD40.3,Pretreatment with amlodipine attenuated the increased expression of CD40 induced by oxLDL but no effect on the basal expression of CD40. Amlodipine can down-regulate CD40 expression in a dose-dependent manner within 0.1-10μmol/l for 24h, significant effect at 1.0μmol/l. and most effect at 10μmol/l. Furthermore, The expression of LOX-1 mRNA was also degraded by amlodipine but no effect on normal endotheliocyte.Conclusions1,oxLDL up-regulated the expression of CD40 in endothelium.2,Blocking Lectin-like oxLDL receptor-1(LOX-1) down-regulated the expression of CD40.3,Amlodipine had a significant effect on down-regulating CD40 expression induced by oxLDL. This salutary effects of amlodipine maybe dependent on the inhibition of the expression of LOX-1.