title: Quercetin attenuates Monocyte Chemoattractant Protein-1 gene expression in glucose primed aortic endothelial cells through NF-kappaB and AP-1.
abstract: Monocyte Chemoattractant Protein-1 (MCP-1) is involved in the diapedesis of blood monocytes into the arterial intima, an early critical event in atherogenesis. Modulating MCP-1 expression can be a key strategy to decrease the risk for atherosclerosis in diabetes. We hypothesized that quercetin, an anti-inflammatory molecule could modulate high glucose concentration (HG) induced MCP-1 expression in aortic endothelial cells in vitro because of its regulatory effects on Activator Protein-1 (AP-1) and Nuclear Factor-kappaB (NF-kappaB). Rat aortic endothelial cells (RAECs) were exposed to HG in the presence or absence of quercetin. Quercetin attenuated HG induced MCP-1 mRNA (42%) and protein synthesis (45%) when estimated using real-time reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay respectively. Western blot analysis found quercetin to maintain cytosolic p65 protein levels to that seen in control. Quercetin was found to attenuate HG induced increased NF-kappaB and AP-1 DNA binding activity in electrophoretic mobility shift assay. Immunofluorescence studies revealed quercetin to prevent HG induced nuclear localization of p65 and c-jun. Quercetin was also found to decrease HG induced activation of NF-kappaB (71%+/-14%), AP-1 (69%+/-24%) and MCP-1 promoter (79%+/-25%) in EA.hy926 cells when analyzed using luciferase reporter assay. We conclude that quercetin attenuates MCP-1 expression in HG treated RAECs, probably by regulating both NF-kappaB and AP-1 pathways. The findings provide new insights into HG induced MCP-1 gene regulation in aortic endothelial cells and the potential of quercetin in abating the risk for atherosclerosis in diabetes.
authors.affiliation: Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
authors.forename: Sumith Retnamma
authors.initials: SR
authors.lastname: Panicker
authors.forename: Prethish
authors.initials: P
authors.lastname: Sreenivas
authors.forename: Mani Sankar
authors.initials: MS
authors.lastname: Babu
authors.forename: Devarajan
authors.initials: D
authors.lastname: Karunagaran
authors.forename: Chandrasekharan Cheranellore
authors.initials: CC
authors.lastname: Kartha
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001011:Aorta / Q000166:cytology; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D011794:Quercetin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; D018932:Chemokine CCL2; D016328:NF-kappa B; D016755:Proto-Oncogene Proteins c-jun; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D011794:Quercetin; D005947:Glucose