title: Antifibrotic effects of pirfenidone in rat proximal tubular epithelial cells.
abstract: OBJECTIVE
  Renal fibrosis is a common cause of renal dysfunction with chronic kidney disease. We previously investigated the renoprotective effects of the antifibrotic agent pirfenidone in a rat model of subtotal nephrectomy. Here, we further evaluated the antifibrotic effects of pirfenidone in rat proximal tubular epithelial cells.
  
  
  METHODS
  NRK52E cells were incubated in a medium containing either transforming growth factor (TGF)-β1 (3 ng/mL) or platelet-derived growth factor (PDGF)-BB (5 Ang/mL) or both, with or without pirfenidone (0.1-1 mmol/L), for 24 h to assess mRNA expression, for 48 h to assess protein production, and for 1 h or various time (5-120 min) to assess phosphorylation of signal kinase.
  
  
  RESULTS
  TGF-β1, a key mediator in renal fibrosis, induced increases in the mRNA expression of various profibrotic factors and extracellular matrix, including plasminogen activator inhibitor type 1 (PAI-1), fibronectin, type 1 collagen, and connective tissue growth factor (CTGF)-increases which pirfenidone significantly inhibited. Specifically, pirfenidone potently inhibited TGF-β1-induced increases in the mRNA expression and protein secretion of PAI-1, an effect mediated, at least in part, via the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling. Further, PDGF-BB, which has been implicated in renal interstitial fibrosis, potently activated PAI-1 expression under TGF-β1 stimulation, and pirfenidone significantly inhibited TGF-β1- and PDGF-BB-induced increases in PAI-1 expression.
  
  
  CONCLUSIONS
  Taken together, these results suggest that TGF-β1 closely correlates with renal fibrosis in cooperation with several fibrosis-promoting molecules, such as PAI-1 and PDGF, in rat proximal tubular epithelial cells, and pirfenidone inhibits TGF-β1-induced fibrosis cascade and will therefore likely exert antifibrotic effects under pathological conditions.
authors.affiliation: Drug Discovery Research, Astellas Pharma Inc., Ibaraki, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Takakura
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tahara
authors.forename: Masanao
authors.initials: M
authors.lastname: Sanagi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Itoh
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tomura
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology; D005355:Fibrosis / Q000188:drug therapy; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000473:pathology*; D011728:Pyridones / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D051381:Rats; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology; D019459:Urothelium / Q000187:drug effects / Q000473:pathology*
chemical_list: D011728:Pyridones; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; C093844:pirfenidone