Ganjie Decoction protects against respiratory syncytial virus infection by activating PI3K/AKT-apoptosis axis and regulating gut microbiota metabolism

Ethnopharmacological relevance Ganjie Decoction (GJD), a traditional Chinese medicine (TCM) formula commonly used for respiratory diseases, has shown therapeutic potential against RSV pneumonia. However, its pharmacological mechanisms against respiratory syncytial virus (RSV) pneumonia are not fully understood. Aim of study This study aimd to characterize the active components of GJD and systematically investigate its therapeutic effects and underlying mechanisms in RSV-induced pneumonia. Materials and methods To evaluate the therapeutic efficacy of GJD in RSV-infected mice, we monitored body weight, performed qPCR, and conducted histopathological examination of lung tissues. The chemical constituents of GJD were characterized using UPLC-MS. Key bioactive compounds and their potential targets were predicted using network pharmacology and molecular docking. The underlying mechanisms were further elucidated using immunohistochemistry and western blotting. The interactions between GJD and the gut microbiota were explored using antibiotic depletion, fecal microbiota transplantation (FMT), metagenomic sequencing, and in vitro co-culture assays. Untargeted metabolomics was employed to assess GJD-induced metabolic alterations. Finally, the role of 4-hydroxyphenylacetic acid (4-HPA) was investigated through cell viability assays, immunofluorescence staining, and western blot analysis in vitro . Results GJD significantly mitigated weight loss, attenuated pulmonary viral load, and suppressed inflammation in RSV-infected mice. Network pharmacology and molecular docking revealed that specific compounds in GJD target the PI3K/AKT signaling pathway. This finding was validated by western blotting and immunohistochemistry, which demonstrated that GJD suppresses PI3K/AKT pathway activation, thereby attenuating apoptosis and ameliorating RSV-induced pneumonia. Notably, these protective effects were markedly attenuated in mice with depleted gut microbiota. Furthermore, the therapeutic effects of GJD against RSV pneumonia were transferable via gut microbiota transplantation. GJD restored RSV-induced dysbiosis of the gut microbiota, with Lactobacillus reuteri emerging as one of the most enriched microbes following treatment. Metabolomics analysis identified 4-HPA as a microbiota-dependent metabolite significantly upregulated by GJD. Remarkably, administration of 4-HPA reproduced GJD’s therapeutic effects in RSV-infected mice and activated the KEAP1/NRF2 antioxidant pathway, suggesting that 4-HPA functions as a key mediator of GJD’s anti-RSV activity. Conclusions These findings suggest that GJD alleviates RSV pneumonia through a synergistic mechanism that modulates the PI3K/AKT–apoptosis pathway, restores gut microbial balance, and normalizes metabolic disturbances. This study systematically elucidates the mechanistic basis underlying the therapeutic effects of GJD against RSV pneumonia.