title: Pirfenidone inhibits transforming growth factor-β1-induced fibrogenesis by blocking nuclear translocation of Smads in human retinal pigment epithelial cell line ARPE-19.
abstract: OBJECTIVE
  Transforming growth factor-β (TGF-β) plays a key role in transforming retinal pigment epithelial (RPE) cells into mesenchymal fibroblastic cells, which are implicated in proliferative vitreoretinopathy. Herein, we tested the effect of pirfenidone, a novel antifibrotic agent, on TGF-β1-mediated fibrogenesis in the human RPE cell line ARPE-19.
  
  
  METHODS
  The effect of pirfenidone on the TGF-β1-induced phenotype in ARPE-19 cells was measured with immunocytochemistry as the change in F-actin. Fibronectin and collagen production was measured with enzyme-linked immunosorbent assay, and cell migration activity was investigated using a scratch assay. Immunoblot analyses of cofilin, sma and mad protein (smad) 2/3, p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and extracellular signal-related kinase expression were conducted to elucidate the cell signaling networks that contribute to the antifibrotic effect of pirfenidone.
  
  
  RESULTS
  Treatment with TGF-β1 induced typical phenotypic changes such as formation of stress fiber running parallel to the long axis of cells and enhanced migration and production of extracellular matrix components such as collagen type I and fibronectin. This fibroblast-like phenotype induced by TGF-β1 was significantly inhibited by pretreatment with pirfenidone in a dose-dependent manner. We also elucidated the TGF-β signaling pathways as the target of the inhibitory effect of pirfenidone. Pirfenidone inhibited TGF-β signaling by preventing nuclear accumulation of active Smad2/3 complexes rather than phosphorylation of Smad2/3.
  
  
  CONCLUSIONS
  These results collectively provide a rational background for future evaluation of pirfenidone as a potential antifibrotic agent for treating proliferative vitreoretinopathy and other fibrotic retinal disorders.
authors.affiliation: Department of Bio and Brain Engineering, KAIST, Daejeon, Republic of Korea. ccbioks@kaist.ac.kr
authors.forename: Kyungsun
authors.initials: K
authors.lastname: Choi
authors.forename: Kihwang
authors.initials: K
authors.lastname: Lee
authors.forename: Seung-Wook
authors.initials: SW
authors.lastname: Ryu
authors.forename: Minju
authors.initials: M
authors.lastname: Im
authors.forename: Koung Hoon
authors.initials: KH
authors.lastname: Kook
authors.forename: Chulhee
authors.initials: C
authors.lastname: Choi
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002454:Cell Differentiation; D002460:Cell Line; D002465:Cell Movement; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D005355:Fibrosis / Q000517:prevention & control; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D011728:Pyridones / Q000494:pharmacology*; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D018630:Vitreoretinopathy, Proliferative / Q000188:drug therapy
chemical_list: D000199:Actins; D000894:Anti-Inflammatory Agents, Non-Steroidal; D005353:Fibronectins; D011728:Pyridones; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1; D003094:Collagen; C093844:pirfenidone; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases