Quercetin attenuates Monocyte Chemoattractant Protein-1 gene expression in glucose primed aortic endothelial cells through NF-kappaB and AP-1.
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.
Panicker
Sumith Retnamma
SR
Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
Sreenivas
Prethish
P
Babu
Mani Sankar
MS
Karunagaran
Devarajan
D
Kartha
Chandrasekharan Cheranellore
CC
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*
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