The Antifibrotic Activity of Prostacyclin Receptor Agonism Is Mediated through Inhibition of YAP/TAZ

Am J Respir Cell Mol Biol. 2019 May;60(5):578-591. doi: 10.1165/rcmb.2018-0142OC.


Idiopathic pulmonary fibrosis is a life-threatening progressive disease characterized by loss of alveolar epithelial cells, inflammation, and aberrant fibroblast activation. The two currently approved therapies do not halt or reverse tissue remodeling, and therefore novel disease-modifying mechanisms are needed. Our results describe YAP/TAZ inhibition through prostacyclin (IP) receptor activation as a novel mechanism that suppresses profibrotic (myo)fibroblast activity. We investigated the antifibrotic properties of the selective IP receptor agonist ACT-333679 using primary human lung fibroblasts. ACT-333679 prevented transforming growth factor β1-induced fibroblast-to-myofibroblast transition, proliferation, extracellular matrix synthesis, and IL-6 and PAI-1 secretion, and exerted relaxant effects in cell contraction assays. ACT-333679 treatment also reverted an established myofibroblast phenotype. Unbiased analysis of ACT-333679-induced whole-genome expression changes in transforming growth factor β1-treated fibroblasts identified significant attenuation of genes regulated by YAP/TAZ, two transcriptional cofactors that are essential for fibrosis. We then demonstrated that ACT-333679, via elevation of cAMP, caused YAP/TAZ nuclear exclusion and subsequent suppression of YAP/TAZ-dependent profibrotic gene transcription. In summary, we offer a rationale for further exploring the potential of IP receptor agonists for the treatment of idiopathic pulmonary fibrosis.

Keywords: TGF-β1; YAP/TAZ; cAMP signaling; idiopathic pulmonary fibrosis; prostacyclin receptor.

MeSH terms

  • Acetates / pharmacology*
  • Acyltransferases
  • Adaptor Proteins, Signal Transducing / genetics*
  • Adaptor Proteins, Signal Transducing / metabolism
  • Case-Control Studies
  • Cell Differentiation
  • Cell Proliferation
  • Cyclic AMP / metabolism
  • Extracellular Matrix / drug effects
  • Extracellular Matrix / metabolism
  • Fibroblasts / drug effects*
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Gene Expression Regulation
  • Humans
  • Idiopathic Pulmonary Fibrosis / drug therapy
  • Idiopathic Pulmonary Fibrosis / genetics
  • Idiopathic Pulmonary Fibrosis / metabolism
  • Idiopathic Pulmonary Fibrosis / pathology
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Lung / metabolism
  • Lung / pathology
  • Male
  • Myofibroblasts / drug effects*
  • Myofibroblasts / metabolism
  • Myofibroblasts / pathology
  • Plasminogen Activator Inhibitor 1 / genetics
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Pyrazines / pharmacology*
  • Receptors, Epoprostenol / agonists
  • Receptors, Epoprostenol / genetics*
  • Receptors, Epoprostenol / metabolism
  • Signal Transduction
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcription, Genetic
  • Transforming Growth Factor beta1 / pharmacology
  • YAP-Signaling Proteins


  • Acetates
  • Adaptor Proteins, Signal Transducing
  • IL6 protein, human
  • Interleukin-6
  • Plasminogen Activator Inhibitor 1
  • Pyrazines
  • Receptors, Epoprostenol
  • SERPINE1 protein, human
  • TGFB1 protein, human
  • Transcription Factors
  • Transforming Growth Factor beta1
  • YAP-Signaling Proteins
  • YAP1 protein, human
  • Cyclic AMP
  • (4-((5,6-diphenylpyrazin-2-yl)(isopropyl)amino)butoxy)acetic acid
  • Acyltransferases
  • TAFAZZIN protein, human