WNT1-inducible signaling protein–1 mediates pulmonary fibrosis in mice and is upregulated in humans with idiopathic pulmonary fibrosis
Melanie Königshoff, Monika Kramer, Nisha Balsara, Jochen Wilhelm, Oana Veronica Amarie, Andreas Jahn, Frank Rose, Ludger Fink, Werner Seeger, Liliana Schaefer, Andreas Günther, Oliver Eickelberg
Melanie Königshoff, Monika Kramer, Nisha Balsara, Jochen Wilhelm, Oana Veronica Amarie, Andreas Jahn, Frank Rose, Ludger Fink, Werner Seeger, Liliana Schaefer, Andreas Günther, Oliver Eickelberg
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Research Article Pulmonology

WNT1-inducible signaling protein–1 mediates pulmonary fibrosis in mice and is upregulated in humans with idiopathic pulmonary fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is characterized by distorted lung architecture and loss of respiratory function. Enhanced (myo)fibroblast activation, ECM deposition, and alveolar epithelial type II (ATII) cell dysfunction contribute to IPF pathogenesis. However, the molecular pathways linking ATII cell dysfunction with the development of fibrosis are poorly understood. Here, we demonstrate, in a mouse model of pulmonary fibrosis, increased proliferation and altered expression of components of the WNT/β-catenin signaling pathway in ATII cells. Further analysis revealed that expression of WNT1-inducible signaling protein–1 (WISP1), which is encoded by a WNT target gene, was increased in ATII cells in both a mouse model of pulmonary fibrosis and patients with IPF. Treatment of mouse primary ATII cells with recombinant WISP1 led to increased proliferation and epithelial-mesenchymal transition (EMT), while treatment of mouse and human lung fibroblasts with recombinant WISP1 enhanced deposition of ECM components. In the mouse model of pulmonary fibrosis, neutralizing mAbs specific for WISP1 reduced the expression of genes characteristic of fibrosis and reversed the expression of genes associated with EMT. More importantly, these changes in gene expression were associated with marked attenuation of lung fibrosis, including decreased collagen deposition and improved lung function and survival. Our study thus identifies WISP1 as a key regulator of ATII cell hyperplasia and plasticity as well as a potential therapeutic target for attenuation of pulmonary fibrosis.

Authors

Melanie Königshoff, Monika Kramer, Nisha Balsara, Jochen Wilhelm, Oana Veronica Amarie, Andreas Jahn, Frank Rose, Ludger Fink, Werner Seeger, Liliana Schaefer, Andreas Günther, Oliver Eickelberg

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Figure 9

Enhanced ECM deposition and myofibroblast marker expression by fibroblasts in response to WISP1.

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Enhanced ECM deposition and myofibroblast marker expression by fibroblas...
(A) NIH 3T3 fibroblasts were stimulated with WISP1 (1 μg/ml; 6 or 12 hours, as indicated), and the mRNA levels of the ECM components Col1a1, Col1a2, fibronectin (Fn1), and the (myo)fibroblast activation markers Fsp1 and Acta2 were analyzed by qRT-PCR (n = 4). Results are plotted as log-fold increase (ΔΔCt) of mRNA levels in WISP1-stimulated versus unstimulated cells and presented as mean ± SEM. (B) NIH 3T3 fibroblasts were stimulated with WISP1 (1 μg/ml) or TGF-β1 (2 ng/ml) for 24 hours, and total collagen content was quantified using the Sircol collagen assay (n = 6). (C) Fibroblast collagen expression and localization after WISP1 stimulation for 24 hours were assessed by immunofluorescence detection of type I collagen 1 (red). Nuclei were visualized by DAPI staining (blue). Data are representative for at least 3 independent experiments. Original magnification, ×40. (D) Human lung fibroblasts were stimulated with WISP1 (1 μg/ml; 6 or 12 hours, as indicated), and the mRNA levels of the ECM components Col1a1, fibronectin (Fn1), the (myo)fibroblast activation markers Fsp1,Acta2, tenascin C (Tnc), and the tissue inhibitor of matrix metalloproteinases 1 (Timp1) were analyzed by qRT-PCR (n = 3) as described in A. (E) Human lung fibroblasts were stimulated with WISP1 (1 μg/ml) or TGF-β1 (2 ng/ml) for 24 hours, and total collagen content was quantified using the Sircol collagen assay (n = 3).*P < 0.05, **P < 0.02.