Wilms tumor 1 impairs apoptotic clearance of fibroblasts in distal fibrotic lung lesions
Harshavardhana H. Ediga, … , Francis X. McCormack, Satish K. Madala
Harshavardhana H. Ediga, … , Francis X. McCormack, Satish K. Madala
Published June 10, 2025
Citation Information: J Clin Invest. 2025;135(15):e188819. https://doi.org/10.1172/JCI188819.
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Research Article Inflammation Pulmonology

Wilms tumor 1 impairs apoptotic clearance of fibroblasts in distal fibrotic lung lesions

Abstract

Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease characterized by impaired fibroblast clearance and excessive extracellular matrix (ECM) protein production. Wilms tumor 1 (WT1), a transcription factor, is selectively upregulated in IPF fibroblasts. However, the mechanisms by which WT1 contributes to fibroblast accumulation and ECM production remain unknown. Here, we investigated the heterogeneity of WT1-expressing mesenchymal cells using single-nucleus RNA-Seq of distal lung tissues from patients with IPF and control donors. WT1 was selectively upregulated in a subset of IPF fibroblasts that coexpressed several prosurvival and ECM genes. The results of both loss-of-function and gain-of-function studies were consistent with a role for WT1 as a positive regulator of prosurvival genes to impair apoptotic clearance and promote ECM production. Fibroblast-specific overexpression of WT1 augmented fibroproliferation, myofibroblast accumulation, and ECM production during bleomycin-induced pulmonary fibrosis in young and aged mice. Together, these findings suggest that targeting WT1 is a promising strategy for attenuating fibroblast expansion and ECM production during fibrogenesis.

Authors

Harshavardhana H. Ediga, Chanukya P. Vemulapalli, Vishwaraj Sontake, Pradeep K. Patel, Hikaru Miyazaki, Dimitry Popov, Martin B. Jensen, Anil G. Jegga, Steven K. Huang, Christoph Englert, Andreas Schedl, Nishant Gupta, Francis X. McCormack, Satish K. Madala

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Figure 5

WT1 functions as a positive regulator of lung-resident fibroblast survival.

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WT1 functions as a positive regulator of lung-resident fibroblast surviv...
(A) Quantification of prosurvival gene (HSP90B1, and PIM1) transcripts using RT-PCR in normal lung fibroblasts transduced with either control or WT1-overexpressing adenoviral particles for 72 hours (n = 3/group). *P < 0.05 and ****P < 0.0001, by multiple unpaired, 2-tailed Student’s t tests for comparisons. (B) Normal lung fibroblasts were transduced with either control or WT1-overexpressing adenoviral particles for 72 hours, and prosurvival gene (BCL2, BCL2-L2, BCL-XL, and BCL3) transcript levels were quantified by RT-PCR (n = 3/group). **P < 0.01, by multiple unpaired, 2-tailed Student’s t tests. (C) Normal lung fibroblasts were transduced with either control or WT1-overexpressing adenoviral particles for 72 hours, and ECM-associated gene (COL1A1, COL6A3, and COL16A1) transcript levels were quantified by RT-PCR (n = 3/group). *P < 0.05 and **P < 0.01, by multiple unpaired, 2-tailed Student’s t tests. (D–I) Normal lung fibroblasts were transduced with either control or WT1-overexpressing adenoviral particles for 72 hours, and cell lysates were immunoblotted with antibodies against WT1, BAD, BAX, FAS, αSMA, or GAPDH. Quantification of WT1, BAD, BAX, FAS, and αSMA protein levels normalized to GAPDH (n = 3/group). *P < 0.05, **P < 0.01, and ***P < 0.001, by 2-tailed Student’s t test. (J) Normal lung fibroblasts were treated with either control or WT1-overexpressing adenoviral particles for 48 hours, followed by anti-Fas antibody treatment for another 24 hours, and fibroblasts were stained for TUNEL (red). Representative confocal images are shown; nuclei were stained with DAPI (blue). Original magnification, ×20. Scale bars: 100 μm. Yellow arrowheads highlight TUNEL+ apoptotic cells. (K) Quantification of TUNEL+ fibroblasts using MetaMorph image analysis (n = 3/group). *P < 0.05 and ****P < 0.0001, by 1-way ANOVA.