IL-4-induced oxidative stress upregulates VCAM-1 gene expression in human endothelial cells.
Vascular cell adhesion molecule-1 (VCAM-1) is expressed in early stages of atherosclerosis; however, the mechanisms of its upregulation are not fully understood. In the present study, we examined the effects of interleukin-4 (IL-4) on VCAM-1 gene expression and its transcriptional regulatory mechanism in human umbilical vein endothelial cells (HUVEC). Reverse transcription-polymerase chain reaction showed that VCAM-1 mRNA was induced in IL-4-treated HUVEC in a time- and dose-dependent manner. Among known transcription factors that have binding sites in the promoter region of the VCAM-1 gene, IL-4 activated only SP-1. In contrast, nuclear factor- kappa B (NF- kappa B), activator protein-1 (AP-1) and interferon regulatory factor-1 (IRF-1), which also have consensus binding sequences in the 5'-flanking region of the human VCAM-1 gene, were not activated. The role of SP-1 in IL-4-induced VCAM-1 expression was confirmed in HUVEC transfected with a reporter construct of the VCAM-1 promoter with mutated SP-1 binding site. As IL-4 treatment of HUVEC enhanced the intracellular oxidizing potential, as indicated by an increase in 2',7'-dichlorofluorescein (DCF) fluorescence, we studied the effect of antioxidants on IL-4-induced VCAM-1 expression. Pretreatment of HUVEC with pyrrolidine dithiocarbamate (PDTC) or N-acetylcysteine (NAC) completely prevented IL-4-induced VCAM-1 expression. In addition, PDTC inhibited IL-4-related activation of SP-1. These results suggest that IL-4-induced oxidative stress upregulates the expression of VCAM-1 gene in HUVEC at transcriptional levels via activation of SP-1 transcription factor. In contrast, NF- kappa B, AP-1 or IRF-1 do not appear to be involved in the signal transduction cascade.
Lee
Y W
YW
Department of Surgery, University of Kentucky Medical Center, Lexington, KY 40536, USA.
Kühn
H
H
Hennig
B
B
Neish
A S
AS
Toborek
M
M
D000111:Acetylcysteine / Q000494:pharmacology; D001161:Arteriosclerosis / Q000209:etiology; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011759:Pyrrolidines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000502:physiology*; D013859:Thiocarbamates / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014471:Umbilical Veins; D015854:Up-Regulation / Q000187:drug effects*; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics
D011759:Pyrrolidines; D016329:Sp1 Transcription Factor; D013859:Thiocarbamates; D014157:Transcription Factors; D019010:Vascular Cell Adhesion Molecule-1; D015847:Interleukin-4; C020972:pyrrolidine dithiocarbamic acid; D000111:Acetylcysteine