title: Stimulation of the soluble guanylate cyclase (sGC) inhibits fibrosis by blocking non-canonical TGFβ signalling.
abstract: OBJECTIVE
  We have previously described the antifibrotic role of the soluble guanylate cyclase (sGC). The mode of action, however, remained elusive. In the present study, we describe a novel link between sGC signalling and transforming growth factor β (TGFβ) signalling that mediates the antifibrotic effects of the sGC.
  
  
  METHODS
  Human fibroblasts and murine sGC knockout fibroblasts were treated with the sGC stimulator BAY 41-2272 or the stable cyclic guanosine monophosphate (cGMP) analogue 8-Bromo-cGMP and stimulated with TGFβ. sGC knockout fibroblasts were isolated from sGCI(fl/fl) mice, and recombination was induced by Cre-adenovirus. In vivo, we studied the antifibrotic effects of BAY 41-2272 in mice overexpressing a constitutively active TGF-β1 receptor.
  
  
  RESULTS
  sGC stimulation inhibited TGFβ-dependent fibroblast activation and collagen release. sGC knockout fibroblasts confirmed that the sGC is essential for the antifibrotic effects of BAY 41-2272. Furthermore, 8-Bromo-cGMP reduced TGFβ-dependent collagen release. While nuclear p-SMAD2 and 3 levels, SMAD reporter activity and transcription of classical TGFβ target genes remained unchanged, sGC stimulation blocked the phosphorylation of ERK. In vivo, sGC stimulation inhibited TGFβ-driven dermal fibrosis but did not change p-SMAD2 and 3 levels and TGFβ target gene expression, confirming that non-canonical TGFβ pathways mediate the antifibrotic sGC activity.
  
  
  CONCLUSIONS
  We elucidated the antifibrotic mode of action of the sGC that increases cGMP levels, blocks non-canonical TGFβ signalling and inhibits experimental fibrosis. Since sGC stimulators have shown excellent efficacy and tolerability in phase 3 clinical trials for pulmonary arterial hypertension, they may be further developed for the simultaneous treatment of fibrosis and vascular disease in systemic sclerosis.
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Beyer
authors.affiliation: Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria Department of Internal Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Zenzmaier
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Palumbo-Zerr
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Rossella
authors.initials: R
authors.lastname: Mancuso
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Alfiya
authors.initials: A
authors.lastname: Distler
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Clara
authors.initials: C
authors.lastname: Dees
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Pawel
authors.initials: P
authors.lastname: Zerr
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jingang
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Maier
authors.affiliation: Department of Trauma and Orthopaedic Surgery, University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Milena L
authors.initials: ML
authors.lastname: Pachowsky
authors.affiliation: Institute for Physiology, Julius-Maximilians-University Würzburg, Würzburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Friebe
authors.affiliation: Bayer Health Care, Global Drug Discovery-Common Mechanism Research, Wuppertal, Germany Hannover Medical School, Institute of Pharmacology, Hannover, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Sandner
authors.affiliation: Department of Rheumatology, University Hospital Zurich, Zürich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Distler
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Schett
authors.affiliation: Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Berger
authors.affiliation: Department of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jörg H W
authors.initials: JH
authors.lastname: Distler
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology*; D005355:Fibrosis / Q000378:metabolism / Q000517:prevention & control; D006162:Guanylate Cyclase / Q000172:deficiency / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists / Q000172:deficiency / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta / Q000187:drug effects / Q000378:metabolism; D012595:Scleroderma, Systemic / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D051785:Smad Proteins / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: C423582:3-(4-Amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo(3,4-b)pyridine; D011720:Pyrazoles; D011725:Pyridines; D018160:Receptors, Cytoplasmic and Nuclear; D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D003094:Collagen; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP