title: Sphingosine 1-phosphate (S1P) receptor agonists mediate pro-fibrotic responses in normal human lung fibroblasts via S1P2 and S1P3 receptors and Smad-independent signaling.
abstract: Synthetic sphingosine 1-phosphate receptor 1 modulators constitute a new class of drugs for the treatment of autoimmune diseases. Sphingosine 1-phosphate (S1P) signaling, however, is also involved in the development of fibrosis. Using normal human lung fibroblasts, we investigated the induction of fibrotic responses by the S1P receptor (S1PR) agonists S1P, FTY720-P, ponesimod, and SEW2871 and compared them with the responses induced by the known fibrotic mediator TGF-β1. In contrast to TGF-β1, S1PR agonists did not induce expression of the myofibroblast marker α-smooth muscle actin. However, TGF-β1, S1P, and FTY720-P caused robust stimulation of extracellular matrix (ECM) synthesis and increased pro-fibrotic marker gene expression including connective tissue growth factor. Ponesimod showed limited and SEW2871 showed no pro-fibrotic potential in these readouts. Analysis of pro-fibrotic signaling pathways showed that in contrast to TGF-β1, S1PR agonists did not activate Smad2/3 signaling but rather activated PI3K/Akt and ERK1/2 signaling to induce ECM synthesis. The strong induction of ECM synthesis by the nonselective agonists S1P and FTY720-P was due to the stimulation of S1P2 and S1P3 receptors, whereas the weaker induction of ECM synthesis at high concentrations of ponesimod was due to a low potency activation of S1P3 receptors. Finally, in normal human lung fibroblast-derived myofibroblasts that were generated by TGF-β1 pretreatment, S1P and FTY720-P were effective stimulators of ECM synthesis, whereas ponesimod was inactive, because of the down-regulation of S1P3R expression in myofibroblasts. These data demonstrate that S1PR agonists are pro-fibrotic via S1P2R and S1P3R stimulation using Smad-independent pathways.
authors.affiliation: Actelion Pharmaceuticals Ltd, 4123 Allschwil, Switzerland.
authors.forename: Katrin
authors.initials: K
authors.lastname: Sobel
authors.forename: Katalin
authors.initials: K
authors.lastname: Menyhart
authors.forename: Nina
authors.initials: N
authors.lastname: Killer
authors.forename: Bérengère
authors.initials: B
authors.lastname: Renault
authors.forename: Yasmina
authors.initials: Y
authors.lastname: Bauer
authors.forename: Rolf
authors.initials: R
authors.lastname: Studer
authors.forename: Beat
authors.initials: B
authors.lastname: Steiner
authors.forename: Martin H
authors.initials: MH
authors.lastname: Bolli
authors.forename: Oliver
authors.initials: O
authors.lastname: Nayler
authors.forename: John
authors.initials: J
authors.lastname: Gatfield
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D058628:Myofibroblasts / Q000378:metabolism* / Q000473:pathology; D010755:Organophosphates / Q000494:pharmacology*; D010069:Oxadiazoles / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D011658:Pulmonary Fibrosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D049349:Receptors, Lysosphingolipid / Q000819:agonists* / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects*; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013876:Thiophenes / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; C525008:FTY 720P; D008246:Lysophospholipids; D010755:Organophosphates; D010069:Oxadiazoles; D049349:Receptors, Lysosphingolipid; C503964:SEW2871; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; C508960:TGFB1 protein, human; D013844:Thiazoles; D013876:Thiophenes; D053773:Transforming Growth Factor beta1; C060506:sphingosine 1-phosphate; C550169:ponesimod; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013110:Sphingosine
keywords: Collagen; Fibroblast; Fibrosis; Impedance; Myofibroblast; S1P Receptor Agonists; Sphingosine-1-phosphate; Transforming Growth Factor Beta (TGFbeta)