title: Caveolin-1 is a negative regulator of MMP-1 gene expression in human dermal fibroblasts via inhibition of Erk1/2/Ets1 signaling pathway.
abstract: BACKGROUND
  Caveolar raft domains, also termed caveolae, are flask shaped invaginations that require the expression of the structural protein caveolin-1 (cav-1). Matrix metalloproteinase 1 (MMP-1) is a collagenase capable of degrading insoluble triple helical collagens. Deregulation of MMP-1 contributes to various pathological processes, including tissue fibrosis and impaired wound healing.
  
  
  OBJECTIVE
  In this study we investigated the role of cav-1 in MMP-1 gene regulation in human dermal fibroblasts.
  
  
  METHODS
  Fibroblasts were isolated from healthy subjects. Western blot was used to analyze protein levels and quantitative real time RT-PCR was used to measure mRNA expression. Cells were transiently transfected with siRNA oligos against acid sphingomyelinase (ASMase) and cav-1, or transduced with adenoviruses overexpressing ASMase and cav-1. The specific pharmacological inhibitors UO126 and SP600125 were used to block Erk1/2 and JNK activity.
  
  
  RESULTS
  This study shows that siRNA-mediated depletion of ASMase or cav-1, results in upregulation of MMP-1 gene expression. Similarly, MMP-1 expression was decreased after overexpresssion of cav-1 via an adenoviral vector. Depletion of cav-1 had no effect on JNK phosphorylation, while it resulted in an increase in Erk1/2 and Ets1 phosphorylation levels. Furthermore, in cav-1 depleted cells treated with the Erk inhibitor UO126, there was no increase in the levels of phospho-Erk1/2, phospho-Ets1, and MMP-1, suggesting that cav-1 mediated effects on MMP-1 and phospho-Ets1 are Erk1/2 dependent.
  
  
  CONCLUSIONS
  In conclusion, this study has revealed an important role for cav-1 as a negative regulator of MMP-1 gene expression via inhibition of Erk1/2/Ets1 signaling. Cav-1 could potentially be a therapeutic target in diseases with deregulated extracellular matrix (ECM) turnover.
authors.affiliation: Boston University School of Medicine, Arthritis Center, Boston, MA USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Haines
authors.forename: Glady H
authors.initials: GH
authors.lastname: Samuel
authors.forename: Heather
authors.initials: H
authors.lastname: Cohen
authors.forename: Maria
authors.initials: M
authors.lastname: Trojanowska
authors.forename: Andreea M
authors.initials: AM
authors.lastname: Bujor
mesh_terms: D015153:Blotting, Western; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D050784:Proto-Oncogene Protein c-ets-1 / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D013108:Sphingomyelin Phosphodiesterase / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; C494041:ETS1 protein, human; D047428:Protein Kinase Inhibitors; D050784:Proto-Oncogene Protein c-ets-1; D012333:RNA, Messenger; D048031:JNK Mitogen-Activated Protein Kinases; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013108:Sphingomyelin Phosphodiesterase; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1