Ginseng stem and leaf saponins attenuates pulmonary fibrosis by regulating TFAM-mtDNA homeostasis and suppressing ZBP1-mediated PANoptosis

Ethnopharmacological relevance: Pulmonary fibrosis (PF) is a progressive interstitial lung disease characterized by alveolar epithelial injury, inflammation, and excessive extracellular matrix deposition, yet current therapeutic options remain limited. Panax ginseng C.A. Meyer, a renowned qi-tonifying herb in traditional Chinese medicine, has long been used to enhance spleen and lung function by replenishing qi. However, the mechanism of action of its primary active component, ginseng stem and leaf saponins (GSLS), in pulmonary fibrosis remains incompletely understood.

Aim of the study: This study aims to elucidate the protective role of GSLS against pulmonary fibrosis by investigating how GSLS regulates mitochondrial transcription factor A (TFAM)-mtDNA homeostasis and suppresses PANoptosis in alveolar epithelial cells.

Materials and methods: The major constituents of GSLS were identified using UHPLC-Q Exactive HFX. A BLM-induced mouse model of pulmonary fibrosis and an MLE-12-primary fibroblast co-culture system were established to evaluate the therapeutic effects of GSLS. Surface plasmon resonance (SPR) and cell thermal shift assays (CETSA) were performed to assess the direct interaction and thermal stability between GSLS and TFAM. Co-immunoprecipitation (Co-IP), RT-qPCR, and immunofluorescence were used to evaluate PANoptosome assembly, cytosolic double-stranded DNA (dsDNA) leakage, and fibrotic marker expression.

Results: GSLS was found to contain multiple active ginsenosides, including Rk2, CK, Rk3, and Rf. In vivo, GSLS markedly alleviated BLM-induced lung pathological injury, reduced Collagen deposition, and decreased oxidative stress. In vitro, GSLS directly bound to TFAM and enhanced its thermal stability. RT-qPCR and immunofluorescence analyses further demonstrated that GSLS effectively suppressed abnormal cytosolic dsDNA leakage, reduced MLE-12 cell death, and ameliorated mitochondrial dysfunction. Moreover, GSLS inhibited the assembly of the PANoptosome complex, suppressed epithelial PANoptosis, and decreased the expression of fibrosis-related proteins.

Conclusion: GSLS mitigates BLM-induced pulmonary fibrosis by stabilizing TFAM, maintaining mtDNA homeostasis, and suppressing PANoptosis. This clarifies the potential mechanism of GSLS therapy for PF.

Ginseng stem and leaf saponins; PANoptosis; Pulmonary fibrosis; TFAM; dsDNA.