Tgf-beta downregulation of distinct chloride channels in cystic fibrosis-affected epithelia.

Academic Article

Abstract

  • RATIONALE: The cystic fibrosis transmembrane conductance regulator (CFTR) and Calcium-activated Chloride Conductance (CaCC) each play critical roles in maintaining normal hydration of epithelial surfaces including the airways and colon. TGF-beta is a genetic modifier of cystic fibrosis (CF), but how it influences the CF phenotype is not understood. OBJECTIVES: We tested the hypothesis that TGF-beta potently downregulates chloride-channel function and expression in two CF-affected epithelia (T84 colonocytes and primary human airway epithelia) compared with proteins known to be regulated by TGF-beta. MEASUREMENTS AND MAIN RESULTS: TGF-beta reduced CaCC and CFTR-dependent chloride currents in both epithelia accompanied by reduced levels of TMEM16A and CFTR protein and transcripts. TGF-beta treatment disrupted normal regulation of airway-surface liquid volume in polarized primary human airway epithelia, and reversed F508del CFTR correction produced by VX-809. TGF-beta effects on the expression and activity of TMEM16A, wtCFTR and corrected F508del CFTR were seen at 10-fold lower concentrations relative to TGF-beta effects on e-cadherin (epithelial marker) and vimentin (mesenchymal marker) expression. TGF-beta downregulation of TMEM16A and CFTR expression were partially reversed by Smad3 and p38 MAPK inhibition, respectively. CONCLUSIONS: TGF-beta is sufficient to downregulate two critical chloride transporters in two CF-affected tissues that precedes expression changes of two distinct TGF-beta regulated proteins. Our results provide a plausible mechanism for CF-disease modification by TGF-beta through effects on CaCC.
  • Published In

  • PLoS ONE  Journal
  • Keywords

  • Anoctamin-1, Cell Line, Chloride Channels, Chlorides, Cyclic AMP, Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator, Down-Regulation, Epithelial Cells, Gene Expression, Humans, Neoplasm Proteins, RNA, Messenger, Respiratory Mucosa, Transforming Growth Factor beta
  • Digital Object Identifier (doi)

    Author List

  • Sun H; Harris WT; Kortyka S; Kotha K; Ostmann AJ; Rezayat A; Sridharan A; Sanders Y; Naren AP; Clancy JP
  • Start Page

  • e106842
  • Volume

  • 9
  • Issue

  • 9