title: Simvastatin inhibits TNFalpha-induced invasion of human cardiac myofibroblasts via both MMP-9-dependent and -independent mechanisms.
abstract: Statins can reduce adverse myocardial remodeling independently of their cholesterol-lowering ability. We have previously reported that simvastatin inhibits tumor necrosis factor-alpha (TNFalpha)-induced cardiac myofibroblast invasion and MMP-9 secretion, key events in this remodeling process. The aim of the present study was to investigate the mechanisms underlying this effect. Selective MMP-9 gene silencing with siRNA oligonucleotides revealed that myofibroblast invasion through a Matrigel barrier (Boyden chamber assay) was MMP-9-dependent. In contrast, cell migration (in the absence of Matrigel) was MMP-9-independent. Simvastatin, a commonly prescribed statin, inhibited both invasion and migration of myofibroblasts and disrupted the actin cytoskeleton as determined by confocal microscopy of rhodamine-phalloidin staining. All these effects of simvastatin were mimicked by the Rho-kinase inhibitor Y27632. TNFalpha activated the ERK-1/2, p38 MAPK, PI-3-kinase and NF-kappaB pathways but not the JNK pathway, as determined by immunoblotting with phospho-specific antibodies. Quantitative RT-PCR revealed that TNFalpha-induced MMP-9 mRNA expression was substantially reduced by pharmacological inhibitors of the ERK-1/2, PI-3-kinase and NF-kappaB pathways. However, none of the signal transduction pathways studied was influenced by simvastatin treatment. Moreover, despite reducing MMP-9 secretion, simvastatin had no effect on MMP-9 promoter activity (luciferase reporter assay) and actually increased MMP-9 mRNA levels. In summary, simvastatin reduces TNFalpha-induced invasion of human cardiac myofibroblasts through two distinct mechanisms: (i) by attenuating cell migration via Rho-kinase inhibition and subsequent cytoskeletal disruption, and (ii) by decreasing MMP-9 secretion via a post-transcriptional mechanism.
authors.affiliation: Academic Unit of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Neil A
authors.initials: NA
authors.lastname: Turner
authors.forename: Parvinder K
authors.initials: PK
authors.lastname: Aley
authors.forename: Kersten T
authors.initials: KT
authors.lastname: Hall
authors.forename: Philip
authors.initials: P
authors.lastname: Warburton
authors.forename: Stacey
authors.initials: S
authors.lastname: Galloway
authors.forename: Lynne
authors.initials: L
authors.lastname: Midgley
authors.forename: David J
authors.initials: DJ
authors.lastname: O'Regan
authors.forename: Ian C
authors.initials: IC
authors.lastname: Wood
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Ball
authors.forename: Karen E
authors.initials: KE
authors.lastname: Porter
mesh_terms: D000199:Actins / Q000378:metabolism; D000577:Amides / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019821:Simvastatin / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D054460:rho-Associated Kinases
chemical_list: D000199:Actins; D000577:Amides; D047908:Intracellular Signaling Peptides and Proteins; D011725:Pyridines; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C108830:Y 27632; D019821:Simvastatin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020780:Matrix Metalloproteinase 9