PT  - JOURNAL ARTICLE
AU  - Aina Martin
AU  - Sarah Vierkotten
AU  - Melanie Königshoff
TI  - Impact of Wnt ligand secretion on cellular phenotypes in pulmonary fibrosis
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P3910
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P3910.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P3910.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Introduction:Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease of unknown etiology characterized by alveolar epithelial injury, myofibroblast activation, and increased extracellular matrix deposition. Reactivation of the WNT pathway has been linked to pulmonary fibrosis. Here, we aim to study cell-specific effects of global (non)-canonical WNT inhibition in fibrotic lung cells. Methods: Lung tissue and bronchoalveolar lavage fluid (BALF) from experimental and human IPF were screened for Wnt ligand expression. Murine and human lung epithelial cells (MLE12 and A549) and Wnt3a L-cells, were used in vitro to study the effects of the Porcupine (Porcn) inhibitor IWP2 on Wnt activity. Cells were treated with different drug concentrations, DMSO as a control, or Wnt3a-conditioned medium. β-catenin-dependent gene transcription was analyzed either by TOP/FOP flash reporter assay or target gene expression by qRT-PCR. Results: Canonical WNT3a and WNT10b levels were significantly elevated in BALF from experimental lung fibrosis. The compound IWP2 exhibited strong dose-dependent efficacy to reduce baseline Wnt activity in MLE12, A549 ( ∼70% reduction at 500nM) and Wnt3a-induced signal activity in L-cells ( ∼75% reduction). Accordingly, the mRNA levels of the Wnt-antagonists AXIN2 and NKD1 were decreased in A549 cells (-1.2-fold and -2.4-fold decrease at 500nM, respectively). Conclusions: Specific Wnt ligands are secreted by epithelial cells in experimental lung fibrosis. The inhibition of Porcn by IWP2 effectively inhibited Wnt activity in lung epithelial cells. Thus, Porcn inhibition is a potent approach to study the impact of Wnt ligand secretion on cellular phenotypes in pulmonary fibrosis.