title: Roles of NF-kappaB and SP-1 in oxidative stress-mediated induction of platelet-derived growth factor-B by TNFalpha in human endothelial cells.
abstract: Platelet-derived growth factor-B (PDGF-B) is upregulated by proinflamatory stimuli in the early stages of atherosclerosis. However, its mechanisms are not fully elucidated. In the present study, by using the antioxidant N-acetylcysteine (NAC), we investigated in human umbilical vein endothelial cells (HUVECs) the roles of oxidative stress in PDGF-B expression induced by tumor necrosis factor alpha (TNFalpha) and its underlying mechanisms. Exposure of HUVECs to TNFalpha (200 U/ml) for 24 hours caused significant increases of both the PDGF-B expression and its promoter/enhancer activity, which were abolished by NAC (20 mmol/L). Accordingly, a prolonged oxidative stress was induced by TNFalpha and that was prevented by pretreatment with NAC. Electrophoresis mobility shift assay (EMSA) and Western blot analysis showed that both the nuclear factor-kappaB (NF-kappaB) and the specificity protein-1 (SP-1) were activated by TNFalpha. However, NAC only partially inhibited the TNFalpha-induced activation of NF-kappaB, but abolished the activation of SP-1. Mutation of the NF-kappaB binding site resulted in a moderate reduction in the TNFalpha-induced activity of PDGF-B promoter/enhancer, whereas mutation of SP-1 binding site resulted in an absence of induction by TNFalpha. These results suggest that oxidative stress mediates the TNFalpha-induced expression of PDGF-B in HUVECs through redox-sensitive transcription factors, predominantly the SP-1 and possibly, to some extent of NF-kappaB.
authors.affiliation: Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China.
authors.forename: Jianru
authors.initials: J
authors.lastname: Shi
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wang
authors.forename: Jin
authors.initials: J
authors.lastname: Qiu
authors.forename: Qin
authors.initials: Q
authors.lastname: Si
authors.forename: Renyu
authors.initials: R
authors.lastname: Sun
authors.forename: Hengyi
authors.initials: H
authors.lastname: Guo
authors.forename: Qixia
authors.initials: Q
authors.lastname: Wu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D016328:NF-kappa B / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D011033:Podophyllin / Q000031:analogs & derivatives* / Q000494:pharmacology; D011034:Podophyllotoxin / Q000031:analogs & derivatives; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins
chemical_list: D000970:Antineoplastic Agents; D016328:NF-kappa B; D020574:Proto-Oncogene Proteins c-sis; D014409:Tumor Necrosis Factor-alpha; C003170:mitopodozide; D011033:Podophyllin; D011034:Podophyllotoxin