title: The Hippo pathway mediates inhibition of vascular smooth muscle cell proliferation by cAMP.
abstract: OBJECTIVE
  Inhibition of vascular smooth muscle cell (VSMC) proliferation by intracellular cAMP prevents excessive neointima formation and hence angioplasty restenosis and vein-graft failure. These protective effects are mediated via actin-cytoskeleton remodelling and subsequent regulation of gene expression by mechanisms that are incompletely understood. Here we investigated the role of components of the growth-regulatory Hippo pathway, specifically the transcription factor TEAD and its co-factors YAP and TAZ in VSMC.
  
  
  RESULTS
  Elevation of cAMP using forskolin, dibutyryl-cAMP or the physiological agonists, Cicaprost or adenosine, significantly increased phosphorylation and nuclear export YAP and TAZ and inhibited TEAD-luciferase report gene activity. Similar effects were obtained by inhibiting RhoA activity with C3-transferase, its downstream kinase, ROCK, with Y27632, or actin-polymerisation with Latrunculin-B. Conversely, expression of constitutively-active RhoA reversed the inhibitory effects of forskolin on TEAD-luciferase. Forskolin significantly inhibited the mRNA expression of the pro-mitogenic genes, CCN1, CTGF, c-MYC and TGFB2 and this was reversed by expression of constitutively-active YAP or TAZ phospho-mutants. Inhibition of YAP and TAZ function with RNAi or Verteporfin significantly reduced VSMC proliferation. Furthermore, the anti-mitogenic effects of forskolin were reversed by overexpression of constitutively-active YAP or TAZ.
  
  
  CONCLUSIONS
  Taken together, these data demonstrate that cAMP-induced actin-cytoskeleton remodelling inhibits YAP/TAZ-TEAD dependent expression of pro-mitogenic genes in VSMC. This mechanism contributes novel insight into the anti-mitogenic effects of cAMP in VSMC and suggests a new target for intervention.
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Tomomi E
authors.initials: TE
authors.lastname: Kimura
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Aparna
authors.initials: A
authors.lastname: Duggirala
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Madeleine C
authors.initials: MC
authors.lastname: Smith
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: White
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Graciela B
authors.initials: GB
authors.lastname: Sala-Newby
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Newby
authors.affiliation: Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol BS2 8HW, UK. Electronic address: mark.bond@bris.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Bond
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D003994:Bucladesine / Q000378:metabolism / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D055515:Cysteine-Rich Protein 61 / Q000235:genetics / Q000378:metabolism; D011464:Epoprostenol / Q000031:analogs & derivatives / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D061251:Primary Cell Culture; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D053778:Thiazolidines / Q000494:pharmacology; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism; D000091102:YAP-Signaling Proteins; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000577:Amides; D051017:Apoptosis Regulatory Proteins; D019086:Bridged Bicyclo Compounds, Heterocyclic; C501849:CCN1 protein, rat; C526316:CCN2 protein, rat; D055515:Cysteine-Rich Protein 61; D047908:Intracellular Signaling Peptides and Proteins; D016271:Proto-Oncogene Proteins c-myc; D011725:Pyridines; C509043:Tgfb2 protein, rat; D053778:Thiazolidines; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D053781:Transforming Growth Factor beta2; C000612286:WWTR1 protein, rat; D000091102:YAP-Signaling Proteins; C509425:Yap1 protein, rat; C108830:Y 27632; D055513:Connective Tissue Growth Factor; D005576:Colforsin; D003994:Bucladesine; D011464:Epoprostenol; D000242:Cyclic AMP; D054460:rho-Associated Kinases; C037068:latrunculin B; C043867:cicaprost
keywords: 3′-5′-Cyclic adenosine monophosphate; TAZ; TEAD; VSMC; YAP; cAMP