title: Nicotine-mediated induction of E-selectin in aortic endothelial cells requires Src kinase and E2F1 transcriptional activity.
abstract: Smoking is highly correlated with enhanced likelihood of atherosclerosis by inducing endothelial dysfunction. In endothelial cells, various cell-adhesion molecules including E-selectin, are shown to be upregulated upon exposure to nicotine, the addictive component of tobacco smoke; however, the molecular mechanisms underlying this induction are poorly understood. Here we demonstrate that nicotine-induced E-selectin transcription in human aortic endothelial cells (HAECs) could be significantly blocked by α7-nAChR subunit inhibitor, α-BT, Src-kinase inhibitor, PP2, or siRNAs against Src or β-Arrestin-1 (β-Arr1). Further, chromatin immunoprecipitations show that E-selectin is an E2F1 responsive gene and nicotine stimulation results in increased recruitment of E2F1 on E-selectin promoter. Inhibiting E2F1 activity using RRD-251, a disruptor of the Rb-Raf-1 kinase interaction, could significantly inhibit the nicotine-induced recruitment of E2F1 to the E-selectin promoter as well as E-selectin expression. Interestingly, stimulation of HAECs with nicotine results in increased adhesion of U937 monocytic cells to HAECs and could be inhibited by pre-treatment with RRD-251. Similarly, depletion of E2F1 or Src using RNAi blocked the increased adhesion of monocytes to nicotine-stimulated HAECs. These results suggest that nicotine-stimulated adhesion of monocytes to endothelial cells is dependent on the activation of α7-nAChRs, β-Arr1 and cSrc regulated increase in E2F1-mediated transcription of E-selectin gene. Therefore, agents such as RRD-251 that can target activity of E2F1 may have potential therapeutic benefit against cigarette smoke induced atherosclerosis.
authors.affiliation: Department of Tumor Biology, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA.
authors.forename: Vignesh
authors.initials: V
authors.lastname: Alamanda
authors.forename: Sandeep
authors.initials: S
authors.lastname: Singh
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Lawrence
authors.forename: Srikumar P
authors.initials: SP
authors.lastname: Chellappan
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D001011:Aorta / Q000166:cytology; D002038:Bungarotoxins / Q000494:pharmacology; D002478:Cells, Cultured; D019040:E-Selectin / Q000235:genetics*; D050687:E2F1 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009538:Nicotine / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D011978:Receptors, Nicotinic / Q000378:metabolism; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D064569:alpha7 Nicotinic Acetylcholine Receptor; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C412373:AG 1879; D000317:Adrenergic alpha-Antagonists; D002038:Bungarotoxins; C579167:Chrna7 protein, human; D019040:E-Selectin; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D011743:Pyrimidines; D034741:RNA, Small Interfering; C556907:RRD 251; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; D009538:Nicotine; D019061:src-Family Kinases; D013890:Thiourea