Phillygenin Alleviates Lipopolysaccharide-Induced Acute Pneumonia by Modulating the Tumor Necrosis Factor α Signaling Pathway

Purpose: There is an urgent need to develop effective anti-pneumonia drugs. Phillygenin (PHI) is derived from Forsythia suspense and possesses anti-inflammation, anti-oxidant bioactivities. In the present study, we aimed to evaluate the therapeutic potential of phillygenin (PHI) on lipopolysaccharide (LPS)-induced acute pneumonia.Methods: The molecular target of PHI was predicted by bioinformatic analysis. Hollow fiber-based ligand fishing (HFLF) strategy and luciferase reporter assay were further used to identify the target of PHI. LPS-induced acute pneumonia rat model and A549 cells model were used to evaluate PHI function. TNF-α pathway and apoptosis associated proteins were detected by Western Blot, immunofluorescence and immunohistochemistry. Cell cycle and cytokines were determined by flow cytometry.Results: The bioinformatic analysis and luciferase reporter assay identified that the target protein of PHI was pregnane X receptor (PXR) PHI could directly bind to PXR protein and inhibit NF-κB P65 activity. PHI significantly decreased the expression of phosphorylated JNK, P38, Erk, P65 in acute pneumonia rat model. PHI also declined the expression of Bax, Caspase-3 and Caspase-9 and repressed lung epithelial cell apoptosis induced by LPS in vivo and in vitro. In addition, PHI inhibited inflammation cytokines production including TNF-α, IFN-γ, IL-6, IL-1β and IL-18.Conclusions: PHI significantly alleviated LPS-induced lung injury in vivo by exerting anti-inflammatory effects. This is the first study to demonstrate that PHI, a small molecule natural product, significantly alleviates LPS-induced acute pneumonia by binding to PXR. Thus, PHI can be a novel therapeutic agent for pneumonia.