title: Sodium nitrite attenuates MMP-9 production by endothelial cells and may explain similar effects of atorvastatin.
abstract: Imbalanced matrix metalloproteinase (MMP) activity promotes cardiovascular alterations that are attenuated by statins. These drugs exert pleiotropic effects independent of cholesterol concentrations, including upregulation of nitric oxide (NO) formation and MMP downregulation. However, statins also increase tissue concentrations of nitrites, which activate new signaling pathways independent of NO. We examined whether atorvastatin attenuates MMP-9 production by human umbilical vein endothelial cells (HUVEC) stimulated with phorbol 12-myristate 13-acetate (PMA) by mechanisms possibly involving increased nitrite, and whether this effect results of NO formation. We also examined whether such an effect is improved by sildenafil, an inhibitor of phosphodiesterase-5 which potentiates NO-induced increases in cyclic GMP. MMP activity and nitrite concentrations were measured by gelatin zymography and ozone-based reductive chemiluminescence, respectively, in the conditioned medium of HUVECs incubated for 24 h with these drugs. Phospho-NFκB p65 concentrations were measured in cell lysate to assess NFκB activation. Atorvastatin attenuated PMA-induced MMP-9 gelatinolytic activity by mechanisms not involving NO, although it increased nitrite concentrations, whereas sildenafil had no effects. Combining both drugs showed no improved responses compared to atorvastatin alone. While sodium nitrite attenuated MMP-9 production by HUVECs, adding hemoglobin (NO scavenger) did not affect the responses to nitrite. Neither atorvastatin nor nitrite inhibited PMA-induced increases in phospho-NFκB p65 concentrations. These findings show that sodium nitrite attenuates MMP-9 production by endothelial cells and may explain similar effects exerted by atorvastatin. With both drugs, the inhibitory effects on MMP-9 production are not dependent on NO formation or on inhibition of NFκB activation. Our findings may help to elucidate important new nitrite-mediated mechanisms by which statins affect imbalanced MMP activity in a variety of cardiovascular disease.
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto, SP, 14049-900, Brazil.
authors.forename: Cesar A
authors.initials: CA
authors.lastname: Meschiari
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto, SP, 14049-900, Brazil.
authors.forename: Lucas C
authors.initials: LC
authors.lastname: Pinheiro
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto, SP, 14049-900, Brazil.
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Guimaraes
authors.affiliation: Department of Morphology and Physiology, Dental School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Gerlach
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto, SP, 14049-900, Brazil. tanus@fmrp.usp.br.
authors.forename: Jose E
authors.initials: JE
authors.lastname: Tanus-Santos
mesh_terms: D000069059:Atorvastatin / Q000494:pharmacology*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects; D000068677:Sildenafil Citrate / Q000494:pharmacology; D012977:Sodium Nitrite / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000378:metabolism
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; C498143:RELA protein, human; D051996:Transcription Factor RelA; D009569:Nitric Oxide; D000069059:Atorvastatin; D000068677:Sildenafil Citrate; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; D006152:Cyclic GMP; D012977:Sodium Nitrite; D013755:Tetradecanoylphorbol Acetate
keywords: Endothelial cells; Matrix metalloproteinase-9; Nitric oxide; Nitrite