Stimulatory effect of homocysteine on interleukin-8 expression in human endothelial cells.
Elevated plasma homocysteine is an independent risk factor for atherosclerosis. An important initial step of atherosclerosis is the adhesion and infiltration of monocytes to the lesion site. It has been shown that the pro-inflammatory cytokine interleukin-8 can rapidly cause rolling monocytes to adhere firmly onto monolayers expressing E-selectin. The objective of the present study was to investigate the effect of homocysteine on interleukin-8 production in human endothelial cells. Cells were incubated with various concentrations of homocysteine for 20 h. The gene expression was determined by real-time PCR and the interleukin-8 protein was measured by immunoassay analysis. Homocysteine enhanced the expression of interleukin-8 in a dose-dependent manner (181% of controls at 2.5 mmol/l homocysteine). Stimulation of gene expression was associated with a parallel increase in interleukin-8 protein synthesis (160% of controls at 5.0 mmol/l homocysteine). By co-incubation of endothelial cells with homocysteine and copper sulfate, a further elevation of interleukin-8 expression (251% of controls) was observed, whereas copper sulfate alone had no stimulatory effect. In conclusion, the present study demonstrated that homocysteine altered endothelial cell function by stimulating interleukin-8 expression, suggesting a contribution of homocysteine to the initiation and progression of atherosclerosis. The formation of homocysteine-induced oxidation products might serve as one of the underlying mechanisms of this effect.
Geisel
Jürgen
J
Department of Clinical Chemistry, Saarland Medical School, Homburg, Germany. kchjgei@uniklinik-saarland.de
Jödden
Verena
V
Obeid
Rima
R
Knapp
Jean Pierre
JP
Bodis
Marion
M
Herrmann
Wolfgang
W
D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D019327:Copper Sulfate / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000187:drug effects*; D006710:Homocysteine / Q000494:pharmacology*; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis / Q000235:genetics*; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016209:Interleukin-8; D012333:RNA, Messenger; D006710:Homocysteine; D002374:Catalase; D019327:Copper Sulfate