Expression characteristics of galectin-3 in silicosis and its mechanism in promoting pulmonary fibrosis via TGF-β1/Smads pathway
- VernacularTitle:半乳糖凝集素-3在矽肺中的表达特征及其通过TGF-β1/Smads通路促进肺纤维化的机制
- Author:
Ying CAO
1
;
Xuxi CHEN
1
;
Shuyu GONG
1
;
Ling ZHANG
2
;
Yuqin YAO
3
;
Wen DU
4
Author Information
- Publication Type:Experiment
- Keywords: silicosis; galectin-3; pulmonary fibrosis; macrophage; fibroblast
- From: Journal of Environmental and Occupational Medicine 2026;43(5):643-650
- CountryChina
- Language:Chinese
- Abstract: Background Silicosis, caused by inhalation of silica (SiO2) dust, remains the most prevalent occupational pneumoconiosis in China. While galectin-3 (Gal-3) is known to play pro-inflammatory and pro-fibrotic roles in various diseases, its specific mechanism in the pathogenesis of silicosis has not been fully clarified. Objective To investigate the role and underlying mechanisms of Gal-3 in silicosis using clinical samples of silicosis and a silicosis mouse model. Methods Lung nodule biopsy samples were collected from patients with stage III pneumoconiosis. Concurrently a silicosis mouse model was constructed via non-exposed tracheal intubation with instillation of a SiO2 suspension. The expression levels of Gal-3 mRNA and protein in the lung tissues of the silicosis model mice were then detected using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) staining. Single-cell transcriptomic sequencing (scRNA-seq) was performed on both human and murine lung samples to analyze the expression of the Gal-3-encoding gene Lgals3 across different cell types. In vitro, RAW264.7 macrophages were treated with varying concentrations of SiO2 suspension for 24 h and 48 h; the expression levels of Gal-3 mRNA and protein were measured by RT-qPCR and Western blot. The Gal-3 inhibitor TD139 was used to intervene in the SiO2-induced in vitro macrophage model, and Western blot was used to detect the intracellular expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and transforming growth factor-β1 (TGF-β1). Finally, mouse embryonic lung fibroblasts NIH/3T3 and Mlg2908 were treated with varying concentrations of recombinant mouse Gal-3 protein (rmGal-3) for 48 h, and Western blot was used to detect the expression of fibrosis markers [(Collagen I, Collagen III, Fibronectin, and α smooth muscle actin (α-SMA)] and proteins associated with the TGF-β1/Smads signaling pathway. Results RT-qPCR and IHC staining showed that both the gene and protein expression levels of Gal-3 were significantly elevated at all consecutive time points in the silicosis mouse model (P < 0.05). scRNA-seq revealed that Lgals3 was aberrantly highly expressed in lung tissues from pneumoconiosis patients and silicosis mouse models, with the highest expression observed in macrophages. After treatment of macrophages with different concentrations of SiO2 for 24 h and 48 h, the mRNA and protein expression levels of Gal-3 were significantly upregulated compared with the control group (P < 0.05). Following TD139 intervention, the protein expression levels of IL-1β, TNF-α, and TGF-β1 in dust-exposed macrophages were markedly downregulated (P < 0.0001). After 48 h of stimulation with rmGal-3, the protein expression levels of Collagen I, Fibronectin, and α-SMA in mouse embryonic lung fibroblasts (NIH/3T3 and Mlg2908) were significantly increased in all treatment groups compared with the control group (P < 0.01). Moreover, Gal-3 treatment markedly upregulated TGF-β1 protein expression in Mlg2908 cells and enhanced the phosphorylation levels of Smad2 and Smad3 (P < 0.0001). Conclusion Gal-3 is abnormally expressed in silicotic lung tissues, which primarily originates from macrophages, and inhibition of Gal-3 suppresses SiO2-induced inflammatory and pro-fibrotic responses. In addition, Gal-3 promotes fibroblast differentiation and extracellular matrix production by activating the TGF-β1/Smads signaling pathway.
