title: Upregulation of RGS2: a new mechanism for pirfenidone amelioration of pulmonary fibrosis.
abstract: Pirfenidone was recently approved for treatment of idiopathic pulmonary fibrosis. However, the therapeutic dose of pirfenidone is very high, causing side effects that limit its doses and therapeutic effectiveness. Understanding the molecular mechanisms of action of pirfenidone could improve its safety and efficacy. Because activated fibroblasts are critical effector cells associated with the progression of fibrosis, this study investigated the genes that change expression rapidly in response to pirfenidone treatment of pulmonary fibroblasts and explored their contributions to the anti-fibrotic effects of pirfenidone.
  
  
  
  We used the GeneChip microarray to screen for genes that were rapidly up-regulated upon exposure of human lung fibroblast cells to pirfenidone, with confirmation for specific genes by real-time PCR and western blots. Biochemical and functional analyses were used to establish their anti-fibrotic effects in cellular and animal models of pulmonary fibrosis.
  
  
  
  We identified Regulator of G-protein Signaling 2 (RGS2) as an early pirfenidone-induced gene. Treatment with pirfenidone significantly increased RGS2 mRNA and protein expression in both a human fetal lung fibroblast cell line and primary pulmonary fibroblasts isolated from patients without or with idiopathic pulmonary fibrosis. Pirfenidone treatment or direct overexpression of recombinant RGS2 in human lung fibroblasts inhibited the profibrotic effects of thrombin, whereas loss of RGS2 exacerbated bleomycin-induced pulmonary fibrosis and mortality in mice. Pirfenidone treatment reduced bleomycin-induced pulmonary fibrosis in wild-type but not RGS2 knockout mice.
  
  
  
  Endogenous RGS2 exhibits anti-fibrotic functions. Upregulated RGS2 contributes significantly to the anti-fibrotic effects of pirfenidone.
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
authors.forename: Haihong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
authors.forename: Suneet
authors.initials: S
authors.lastname: Mehrotra
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Abel
authors.affiliation: Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Myron L
authors.initials: ML
authors.lastname: Toews
authors.affiliation: Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, USA.
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Wolff
authors.affiliation: Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, University of Nebraska Medical Center, Omaha, NE, USA.|Clinical Discovery Unit, AstraZeneca, Cambridge, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Rennard
authors.affiliation: Pulmonary, Allergy and Critical Care Division, Airways Biology Initiative, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Reynold A
authors.initials: RA
authors.lastname: Panettieri
authors.affiliation: Department of Internal Medicine, University of South Florida School of Medicine, Tampa, FL, 33620, USA. tbcasale@health.usf.edu.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Casale
authors.affiliation: Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA. Yat6033@creighton.edu.
authors.forename: Yaping
authors.identifier: 0000-0001-5990-3157
authors.initials: Y
authors.lastname: Tu
mesh_terms: D000818:Animals; D001761:Bleomycin; D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020411:Oligonucleotide Array Sequence Analysis; D011728:Pyridones / Q000494:pharmacology*; D020710:RGS Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
chemical_list: D011728:Pyridones; D020710:RGS Proteins; C087182:RGS2 protein, human; D012333:RNA, Messenger; C105345:Rgs2 protein, mouse; D001761:Bleomycin; C093844:pirfenidone; D013917:Thrombin
keywords: Bleomycin; Early response genes; Fibroblast to myofibroblast differentiation; Human fetal lung fibroblasts; Idiopathic pulmonary fibrosis; Knockout; Pirfenidone; Primary human pulmonary fibroblasts; Proliferation; RGS2