title: Intestinal myofibroblast TRPC6 channel may contribute to stenotic fibrosis in Crohn's disease.
abstract: BACKGROUND
  Intestinal fibrosis is a frequent complication of Crohn's disease (CD) and often leads to detrimental stricture formation. Myofibroblasts play active roles in mediating fibrotic changes in various tissues. We investigated whether transient receptor potential channels in intestinal myofibroblasts are involved in CD-associated intestinal fibrosis.
  
  
  METHODS
  An intestinal myofibroblast cell line (InMyoFibs) was stimulated with transforming growth factor-β1 (TGF-β1) to model excessive fibrosis. Biopsy samples from nonstenotic or stenotic intestinal regions from patients with CD were used for quantitative comparisons of transient receptor potential channel and fibrosis-associated factor expression levels.
  
  
  RESULTS
  TGF-β1 treatment transformed spindle-shaped InMyoFibs into filament-shaped cells with enhanced α-actin stress fiber formation, transient receptor potential canonical (TRPC) 4 and TRPC6 messenger RNA and protein expression, and basal- and agonist-induced Ca influxes. TGF-β1 also enhanced the formation of TRPC6/smooth muscle α-actin, TRPC6/N-cadherin, and TRPC4/N-cadherin coimmunoprecipitates. Inhibition of TRPC6 in InMyoFibs by RNA interference or dominant-negative mutations suppressed TGF-β1-induced Ca influxes, stress fiber formation, and smooth muscle α-actin expression, but increased COL1A1, interleukin (IL)-10, and IL-11 expression, as well as Smad-2, ERK, and p38-MAPK phosphorylation. Similar increases in phosphorylation levels were observed with TRPC and calcineurin inhibitors. In stenotic areas in patients with CD, TRPC6, ACTA2 (smooth muscle α-actin), CDH2 (N-cadherin), COL1A1, IL-10, and IL-11 were significantly increased.
  
  
  CONCLUSIONS
  These results suggest that augmented Ca influxes due to TRPC6 upregulation facilitate stress fiber formation and strengthen cell-cell interactions by negatively regulating the synthesis of antifibrotic factors in TGF-β1-treated myofibroblasts. Similar changes observed in stenotic areas of patients with CD suggest the therapeutic significance of targeting TRPC6.
authors: Departments of *Physiology and †Gastroenterology, Fukuoka University School of Medicine, Fukuoka University, Fukuoka, Japan; and ‡Joint Laboratory for Frontier Medical Science, Fukuoka University School of Medicine, Fukuoka University, Fukuoka, Japan.
authors: Lin Hai
authors: LH
authors: Kurahara
authors: Miho
authors: M
authors: Sumiyoshi
authors: Kunihiko
authors: K
authors: Aoyagi
authors: Keizo
authors: K
authors: Hiraishi
authors: Kyoko
authors: K
authors: Nakajima
authors: Midori
authors: M
authors: Nakagawa
authors: Yaopeng
authors: Y
authors: Hu
authors: Ryuji
authors: R
authors: Inoue
mesh_terms: D000328:Adult; D015153:Blotting, Western; D002478:Cells, Cultured; D003108:Colonic Diseases / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D003424:Crohn Disease / Q000150:complications* / Q000473:pathology; D005260:Female; D005355:Fibrosis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D000074287:TRPC6 Cation Channel; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D053773:Transforming Growth Factor beta1