Ginsenoside Rg6 ameliorates COPD by targeting RAGE to suppress MAPK/NF-κB signaling, thereby preserving alveolar barrier integrity and attenuating EMT

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is pathologically characterized by progressive alveolar epithelial barrier disruption, a pathological process primarily driven by chronic cigarette smoke exposure. While Ginsenoside Rg6 (Rg6) has shown therapeutic promise in pulmonary injury models, its direct molecular targets and the precise mechanisms by which it preserves barrier integrity remain unclear. PURPOSE: This study investigates whether Rg6 mitigates COPD by directly targeting the RAGE receptor, thereby suppressing the downstream signaling axes concurrently preserve alveolar barrier integrity and attenuate epithelial-mesenchymal transition (EMT). METHODS: The therapeutic efficacy of Rg6 was evaluated in CSE-challenged MLE-12 alveolar epithelial cells and an LPS/CS-driven mouse COPD model. Transcriptomic profiling was utilized to identify upstream regulatory nodes. Direct Rg6-RAGE engagement was rigorously validated via molecular docking, MD simulations, surface plasmon resonance (SPR), DARTS, and CETSA. The functional dependency of Rg6's protective effects on RAGE was dissected using siRNA knockdown in vitro and AAV-shRAGE delivery in vivo. RESULTS: Oral Rg6 significantly ameliorated pulmonary function decline, emphysema, and the inflammatory microenvironment in COPD mice, achieving efficacy comparable to dexamethasone. Crucially, Rg6 effectively preserved alveolar barrier integrity, restored tight junctions, and attenuated EMT-associated phenotypic shifts. Transcriptomic profiling identified the AGE-RAGE axis as the central upstream hub governing this structural protection. Comprehensive biophysical assays confirmed that Rg6 directly binds to and thermodynamically stabilizes the RAGE protein pocket. Mechanistically, Rg6 suppressed RAGE-mediated hyperactivation of the MAPK (p38, JNK) and NF-κB (p65) cascades, which serve as the central drivers for tight junction disassembly and EMT in epithelial cells. Furthermore, RAGE ablation in vitro and in vivo demonstrated that Rg6's capacity to preserve epithelial architecture is primarily RAGE-dependent. CONCLUSIONS: Rg6 directly targets alveolar RAGE to inhibit the RAGE-MAPK/NF-κB signaling cascade. By suppressing this axis, Rg6 concurrently preserves alveolar barrier integrity and attenuates EMT-like transitions, actively restoring alveolar structural homeostasis and positioning it as a promising therapeutic candidate for COPD.