Synergistic regulation of TGF-β1/Smad2/3 signaling and inflammatory pathways via SA/NAC-based nanoplatforms: a novel strategy to enhance anti-fibrotic therapeutic outcomes in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF), a chronic interstitial lung disease, is characterized by progressive fibrosis and poor prognosis, with no current therapies capable of reversing the fibrotic changes. The aberrant repair driven by fibroblast activation and an inflammatory microenvironment results in irreversible IPF. In this work, a macrophage-derived apoptotic body delivery system (SA + NAC@AB) co-loaded with sodium arsenite (SA) and N-acetylcysteine (NAC) was developed to exert synergistic antifibrotic activity against IPF via coordinated regulation of TGF-β1 signaling and inflammation. Apoptotic bodies derived from macrophages inherit inflammation-homing capability, enabling targeted delivery to fibrotic lesions. In vivo evaluation in a bleomycin-induced IPF mouse model demonstrated that SA + NAC@AB effectively targeted the lungs, significantly improved body weight and survival, and alleviated pulmonary fibrosis. Immunofluorescence and Western blot analyzes revealed that SA + NAC@AB reduced Smad2/3 phosphorylation and M2 macrophage polarization, indicating regulation of the TGF-β1/Smad2/3 pathway and inflammation as part of its mechanism of action. Furthermore, in vitro studies validated the enhanced efficacy of SA + NAC@AB, which significantly promoted fibroblast uptake, thereby potentiating its inhibitory effects on fibroblast viability, as well as TGF-β1-induced migration and differentiation. In conclusion, our study demonstrates that SA + NAC@AB represents an effective therapeutic strategy for IPF, offering a promising novel approach by modulating both the TGF-β1/Smad2/3 signaling pathway and the inflammatory response.