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 8

EMT of ATII cells in response to WISP1.

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EMT of ATII cells in response to WISP1. (A) Primary mouse ATII cells wer...
(A) Primary mouse ATII cells were stimulated with WISP1 (1 μg/ml, 12 hours), and the mRNA levels of the EMT marker genes Tjp1, Cdh1, Ocln, Fsp1, Vim, and Acta2 were analyzed by qRT-PCR (n = 5 for each). (B) Primary ATII cells were stimulated with WISP1 (1 μg/ml, 12 hours) in the absence or presence of neutralizing α-WISP1 antibodies or preimmune serum (IgG control). EMT was assessed by immunofluorescence detection of α-SMA expression (left panels, original magnification, ×10) and colocalization of α-SMA (green) and TJP1 (red) (middle and right panels; original magnification, ×40). Nuclei were visualized by DAPI staining. (C) The migration of ATII cells in response to WISP1 was determined in a Boyden chamber assay; TGF-β1 (2 ng/ml) was used as a positive control. Data are presented as the mean ± SEM of 2 independent experiments performed in triplicate. (D) Primary ATII cells were stimulated with WISP1 (1 μg/ml, 12 hours), and the mRNA levels of the metalloproteinases Mmp2, Mmp7, and Mmp9 and the profibrotic marker genes Pai1 and Spp1 were analyzed by qRT-PCR (n = 5 for each) and plotted as log-fold increase (ΔΔCt) of mRNA levels in WISP1-stimulated versus unstimulated cells. (E) The mRNA levels of the EMT marker genes Tjp1, Cdh1, Ocln, Fsp1, Vim, and Acta2 were determined by qRT-PCR in primary ATII cells isolated from saline- or bleomycin-treated mice 14 days after administration (n = 6). All qRT-PCR results are presented as mean ± SEM. **P < 0.02, *P < 0.05.