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Updated: May 18, 2026
Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo
Published on: May 5, 2023
Inhibition of macrophage migration inhibitory factor attenuates bleomycin-induced murine pulmonary fibrosis via the
Jingwei Wang1,2, Wei Zhao1, Nafeisa Dilixiati1
1Clinical Center for Interstitial Lung Diseases, Department of Occupational Medicine and Toxicology, Beijing Institute of Respiratory Medicine, Beijing Chaoyang Hospital, Capital Medical University, No.8 Worker's Stadium, Chaoyang District, Beijing, 100020, China.
Background:
Idiopathic Pulmonary Fibrosis (IPF) is a chronic progressive disease marked by excessive extracellular matrix deposition and deteriorating lung function. Although macrophage migration inhibitory factor (MIF) has been implicated in pulmonary fibrosis, the downstream mechanisms-particularly whether MIF drives fibrosis through its receptor CD74-remain insufficiently understood. This study investigated whether MIF/CD74 signaling promotes fibroblast activation through specific downstream pathways that regulate proliferation and matrix production.
Methods:
Single-cell RNA sequencing and ELISA were used to characterize MIF-CD74 interactions and circulating MIF levels in IPF patients. Bleomycin-induced fibrosis models were established using C57BL/6J mice, Mif⁻/⁻ mice, and the MIF inhibitor 4-IPP. Macrophage-fibroblast co-culture systems were treated with bleomycin, 4-IPP, or CD74 shRNA. Lung injury, fibrosis, and signaling activation were assessed by histology, qRT-PCR, Western blotting, and functional assays.
Results:
scRNA-seq identified MIF-CD74 as a dominant macrophage-fibroblast signaling axis in fibrotic lungs, and serum MIF levels were elevated in IPF patients. In mice, bleomycin markedly increased MIF and CD74 expression and activated MAPK signaling. Genetic deletion or pharmacologic inhibition of MIF attenuated collagen deposition, improved lung architecture, and reduced profibrotic and inflammatory signaling. In vitro, MIF promoted fibroblast proliferation, migration, and matrix synthesis, whereas CD74 knockdown or MIF inhibition significantly attenuated fibroblast profibrotic responses.
Conclusions:
MIF promotes pulmonary fibrosis by activating CD74-dependent MAPK signaling in fibroblasts, enhancing their proliferation and extracellular matrix production. Targeting the MIF/CD74 axis reduces tissue remodeling and represents a promising therapeutic strategy for IPF.
Insights
Macrophage migration inhibitory factor (MIF) drives idiopathic pulmonary fibrosis (IPF) by activating its receptor CD74. Targeting this MIF/CD74 signaling pathway in fibroblasts reduces lung tissue remodeling and offers a potential IPF therapy.
Area of Science:
- Pulmonary Medicine
- Immunology
- Cell Biology
Background:
- Idiopathic Pulmonary Fibrosis (IPF) is a progressive lung disease characterized by excessive extracellular matrix deposition and declining lung function.
- The role of macrophage migration inhibitory factor (MIF) in pulmonary fibrosis is recognized, but its downstream mechanisms, particularly via its receptor CD74, require further elucidation.
- This study aimed to investigate how MIF/CD74 signaling promotes fibroblast activation, proliferation, and matrix production in IPF.
Purpose of the Study:
- To investigate the role of MIF/CD74 signaling in promoting fibroblast activation and extracellular matrix production in Idiopathic Pulmonary Fibrosis (IPF).
- To explore the downstream signaling pathways, including MAPK, involved in MIF-driven fibrosis.
- To evaluate the therapeutic potential of targeting the MIF/CD74 axis in preclinical models of pulmonary fibrosis.
Main Methods:
- Utilized single-cell RNA sequencing and ELISA to analyze MIF-CD74 interactions and serum MIF levels in IPF patients.
- Employed bleomycin-induced mouse models of pulmonary fibrosis, including wild-type, Mif knockout mice, and treatment with a MIF inhibitor (4-IPP).
- Conducted in vitro macrophage-fibroblast co-culture experiments with bleomycin, 4-IPP, or CD74 shRNA, assessing lung injury, fibrosis, and signaling pathways via histology, qRT-PCR, and Western blotting.
Main Results:
- Single-cell RNA sequencing identified MIF-CD74 as a key signaling axis between macrophages and fibroblasts in fibrotic lungs, with elevated serum MIF in IPF patients.
- Bleomycin treatment increased MIF and CD74 expression and activated MAPK signaling in mice. Genetic or pharmacologic inhibition of MIF reduced collagen deposition and improved lung architecture.
- In vitro, MIF enhanced fibroblast proliferation, migration, and matrix synthesis, effects significantly diminished by CD74 knockdown or MIF inhibition.
Conclusions:
- MIF promotes pulmonary fibrosis by activating CD74-dependent MAPK signaling in fibroblasts, thereby increasing their proliferation and extracellular matrix production.
- Targeting the MIF/CD74 axis effectively reduces tissue remodeling in preclinical models.
- Inhibition of the MIF/CD74 pathway represents a promising therapeutic strategy for managing IPF.
