Study on the activity and mechanism of herbal formula anti-infection powder (AIP) against influenza-virus-induced pneumonia through genetic susceptibility genes.

Ethnopharmacological Relevance: Anti-infection powder (AIP), a patented Chinese herbal formulation, is used traditionally in the treatment of upper respiratory tract infections. In this study, an ethanol extract of AIP was demonstrated to inhibit influenza A virus (IAV) infection and IAV-induced pneumonia (IVP), both in vitro and in vivo, highlighting its potential mechanism of action.

Aim Of The Study: To determine the anti-IAV activity of AIP and to explore the possible mechanisms of inhibiting IAV-induced pneumonia.

Materials And Methods: An ethanol extract was extracted from AIP and its major ingredients were determined by high-performance liquid chromatography (HPLC). An IAV-infected A549 cell model and an IAV-induced mouse pneumonia model were established to evaluate the therapeutic effects of AIP on IVP in vivo and in vitro. The mice were respectively administered AIP at high- and low-dose in different groups. The anti-IAV activity of AIP was evaluated by detecting viral load, lung lesion, lung index, suvival time, inflammatory cytokines and transcriptomic analysis in the lung tissue. The potential pathways and targets that involved in AIP against IVP were predicted by network pharmacology. Mendelian randomization (MR), colocalization analysis, and molecular docking were employed to identify novel therapeutic targets for IVP. Polymerase chain reaction (PCR) and Western blot (WB) techniques were used to confirm the effect of AIP on the expression of risk target genes in the lungs of IVP mice.

Results: In A549 cell line, AIP effectively inhibited IAV infection with IC values of 65.49 μg/mL. The anti-IAV activity of AIP was mainly determined by chlorogenic acid, forsythiarin, puerarin, paeoniflorin and prim-o-glucosylcimigin. Moreover, AIP inhibited the neuraminidase activity and the M gene expression in vitro. In vivo, oral administration of AIP significantly reduced viral load and improved lung tissue lesions. AIP decreased the concentration of pro-inflammatory factors such as IL-1β, TNF-α, and IFN-γ, and significantly increased the concentration of the anti-inflammatory factor IL-4. According to network pharmacology analysis, toll-like receptor signaling pathway, chemokine signaling pathway, and TNF signaling pathway may be the possible mechanisms by which AIP inhibits IVP and regulates excessive inflammatory response.Two new genes, LRG1 and PSMA4, associated with genetic susceptibility to influenza and pneumonia, predicted as potential IVP drug target genes by MR and colocalization analysis. The antiviral mechanism of AIP may be to inhibit the expression levels of LRG1 and PSMA4 in lungs of mouse IVP.

Conclusions: AIP exhibited anti-IAV activities both in vitro and in vivo. AIP had a protective effect against pneumonia caused by influenza virus and can inhibit the progression of inflammation. This effect may be associated with its ability to inhibit the expression levels of genetic susceptibility genes (LRG1 and PSMA4) in lungs of mouse IVP. The findings of this study enhance our understanding of the role and mechanisms of AIP in the treatment of IVP.