Ginsenoside Rg3 Mitigates LPS-Induced Injury in Human Bronchial Epithelial Cells by Restoring Autophagic Flux and Inhibiting the TLR4/NF-κB-Mediated Inflammatory Response.

Purpose: To elucidate the molecular mechanism by which ginsenoside Rg3 (G-Rg3) protects human bronchial epithelial (HBE) cells against lipopolysaccharide (LPS)-induced injury, focusing on its regulation of autophagic flux and the TLR4/NF-κB-mediated inflammatory pathway. Methods: HBE cells were treated with LPS (1-100 ng/mL) to induce autophagy dysregulation and inflammation. G-Rg3 (2-16 μM) was administered to evaluate its protective effects. Western blotting was used to detect autophagy-related proteins (ATG4B, ATG7, PIK3C3, LC3B, p62) and TLR4/NF-κB signaling molecules; ELISA quantified proinflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6, IL-8); PI staining and flow cytometry analyzed cell death and apoptosis. Results: LPS dose-dependently upregulated the expression of autophagy-related proteins (ATG4B, ATG7, PIK3C3, p62, LC3B-II), with accumulated p62 and LC3B-II indicating impaired clearance of autophagic substrates. Additionally, G-Rg3 inhibited LPS-induced TLR4/NF-κB activation, suppressed proinflammatory cytokine secretion, and attenuated HBE cell apoptosis/necrosis. Conclusion: G-Rg3 mitigates LPS-induced HBE cell injury by dual mechanisms: restoring impaired autophagic flux and inhibiting the TLR4/NF-κB inflammatory cascade. These findings identify G-Rg3 as a promising therapeutic agent targeting the crosstalk between autophagy and inflammation in respiratory diseases such as COPD and acute lung injury.