BackgroundInfluenza virus-induced pneumonia (IVP) is an infectious pulmonary disease characterized by exacerbated pulmonary inflammation caused by invasion of the influenza virus. IVP continues to threaten public health due to its high morbidity and mortality rates. Geniposide is one of the major bioactive constituents of G. jasminoides, which exerts antiviral and anti-inflammatory effects on influenza A virus (IAV) infection. PurposeTo investigate therapeutic effects and comprehensive mechanisms of geniposide on IAV infection and subsequent pneumonia. MethodsICR mice were infected intranasally with H1N1 (A/FM/1/47) to detect the anti-IAV activity of geniposide. Proteomics combined with function-integrated analysis were conducted to gain insight into the comprehensive mechanisms of geniposide. Subsequently, western blot was used to detect the phosphorylation of signal transducer and activator of transcription 1 (STAT1), signal transducer and activator of transcription 2 (STAT2), Interferon regulatory factor 9 (IRF9) and Janus kinase 1 (JAK1) in Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in lung tissue. Finally, RT-qPCR was used to detect the levels of interleukin 6 (IL-6), interleukin 17 (IL-17), interferon-γ (IFN-γ) and the STAT1 inhibitor (fludarabine) was used to verify the targeting between STAT1 and geniposide in RAW cells. ResultsGeniposide could significantly reduce the lung index, diminish lung pathology, decrease the virus loads and the inflammatory cytokines expression induced by IAV infection. A total of 411 differentially expressed proteins were identified among control, model, and geniposide-treated group in proteomic analysis. According to function-integrated analysis, 15 KEGG pathways were enriched and divided into 9 groups (modules), including influenza A, NOD-like receptor signaling, RIG-I-like receptor signaling, and so on. Among these modules, the most intensely interacting module pair was the NOD-like receptor signaling and influenza A, in which STAT1 and STAT2 acted as hubs with critical bridgeness role in the target network of geniposide. This indicated that geniposide may mitigate inflammation and alleviate IVP by JAK/STAT signaling pathways. Moreover, validation experiments confirmed that geniposide can significantly inhibit STAT1 and STAT2 phosphorylation as well as down-regulated expression of IL-6, IFN-γ and IL-17 in lung. Furthermore, when RAW cells were treated with the STAT1 inhibitor (fludarabine), the inhibitory effect of geniposide on IFN-γ and IL-6 was attenuated significantly. ConclusionsGeniposide can attenuate IAV-induced pneumonia by regulating inflammatory cytokines production through the JAK/STAT pathway.
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