title: Quercetin exerts multiple inhibitory effects on vascular smooth muscle cells: role of ERK1/2, cell-cycle regulation, and matrix metalloproteinase-9.
abstract: The French paradox has been attributed to the antioxidant properties of flavonoids present in the red wine. Quercetin, a bioflanoid present in the human diet, is known to inhibit angiotensin II-induced hypertrophy and serum-induced smooth muscle cell proliferation. However, it is not known whether quercetin exerts similar cardioprotective effects in cells treated with TNF-alpha. In this study, we investigated whether quercetin exerts the multiple suppressive effects on cytokine TNF-alpha-induced human aortic smooth muscle cells (HASMC). Treatment of quercetin showed potent inhibitory effects on the DNA synthesis of cultured HASMC in the presence of TNF-alpha. These inhibitory effects were associated with reduced extracellular signal-regulated kinase (ERK)1/2 activity and G1 cell-cycle arrest. Treatment of quercetin, which induced a cell-cycle block in G1-phase, induced down-regulation of cyclins and CDKs and up-regulation of the CDK inhibitor p21 expression, whereas up-regulation of p27 or p53 by quercetin was not observed. Because anti-atherogenic effects need not be limited to antiproliferation, we decided to examine whether quercetin exerted inhibitory effects on matrix metalloproteinase-9 (MMP-9) activity in TNF-alpha-induced HASMC. Quercetin inhibited TNF-alpha-induced MMP-9 secretion on HASMC in a dose-dependent manner. This inhibition was characterized by down-regulation of MMP-9, which was transcriptionally regulated at NF-kappaB site and activation protein-1 (AP-1) site in the MMP-9 promoter. These findings indicate the efficacy of quercetin in inhibiting cell proliferation, G1- to S-phase cell-cycle progress, and MMP-9 expression through the transcription factors NF-kappaB and AP-1 on TNF-alpha-induced HASMC.
authors.affiliation: National Research Laboratory for Glycobiology, Korean Ministry of Science and Technology, Kyungju, 780-714, Kyungbuk, Republic of Korea.
authors.forename: Sung-Kwon
authors.initials: SK
authors.lastname: Moon
authors.forename: Gi-Ok
authors.initials: GO
authors.lastname: Cho
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Jung
authors.forename: Sang-Wan
authors.initials: SW
authors.lastname: Gal
authors.forename: Taeg Kyu
authors.initials: TK
authors.lastname: Kwon
authors.forename: Young-Choon
authors.initials: YC
authors.lastname: Lee
authors.forename: Nageswara R
authors.initials: NR
authors.lastname: Madamanchi
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000096:biosynthesis / Q000378:metabolism; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011794:Quercetin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D011794:Quercetin; D018844:Cyclin-Dependent Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020780:Matrix Metalloproteinase 9