Exosome miRNA profile and mitigating effect of miR-23a-3p/Cul3 axis on apoptosis in the pathogenesis of SiO2 dust-induced lung fibrosis

Silicosis is an irreversible interstitial lung fibrosis resulting from persistent inflammation induced by long-term inhalation of SiO₂ dust. Treatment and early diagnosis are extremely challenging due to the lack of specific targets and biomarkers. MiRNAs play an important role in the early diagnosis and treatment of various diseases, due to their stability, small variations, and easy detection. Exosomes have become fashionable candidates to deliver miRNAs. However, the specific role of exosomes-loaded miRNAs in silicosis inflammation and fibrosis remains unclear. In the present study, the expression profile of serum exosomal miRNAs in the peripheral blood of silicosis patients was determined by transcritome sequencing. MiR-23a-3p was recognized as a protector against silicosis by bioinformatic analysis. The expression and regulatory axis of miR-23a-3p and its predicted target gene CUL3 were then confirmed. The therapeutic role of the miR-23a-3p/CUL3 axis and its alleviating effect on SiO₂-induced apoptosis were verified in mice and in epithelial cells. Furthermore, the communication of exosomes carrying miR-23a-3p between macrophages and epithelial cells was demonstrated using a cell co-culture model. Our results suggest that exosomal miR-23a-3p could be prospective as a biomarker in early diagnose for SiO₂-induced lung fibrosis, and provided new threads for the treatment of silicosis.