Influences of notoginsenoside R1 on the injury of alveolar epithelial cells infected by Klebsiella pneumoniae by regulating JAK2STAT3 signaling pathway / 中国热带医学

ABSTRACT

@#Abstract: Objective　To investigate the influences of notoginsenoside R1 (NGR1) on cell injury and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway of alveolar epithelial cells infected by Klebsiella pneumoniae (Kp). Methods　A549 cells were grouped into five groups: control group (C group), infection group (Infect group), infection + low NGR1 group (Infect + L-NGR1 group), infection + high NGR1 group (Infect + H-NGR1 group), and infection+high NGR1+JAK2/STAT3 pathway inhibitor group (Infect+H-NGR1+SD-1029 group). Cell proliferation was measured using CCK8; ELISA kits were applied to detect the contents of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interferon γ (IFN-γ) in the culture medium; flow cytometry was applied to detect apoptosis; RT-qPCR was applied to detect the expressions of JAK2/STAT3; Western blot was applied to detect JAK2/STAT3 pathway, autophagy protein microtubule-associated protein 1 light chain 3 (LC3), autophagy-relatedgene5 (Atg5), autophagy-related gene (Atg) 6 (Beclin-1), apoptosis protein B-cell lymphoma 2 (Bcl-2), Bcl-2-accociated protein (Bax), cysteinyl aspartate specific proteinase (cleaved-caspase-3) proteins expression. Results　Compared with the C group, the 72 h cell viability, the protein levels of Bcl-2, LC3-II/I, Atg5, Beclin-1, the mRNA relative expressions and protein phosphorylation levels of JAK2, STAT3 in the Infect group were obviously decreased (P<0.05); the contents of IL-1β, TNF-α, IFN-γ, apoptosis rate, the protein levels of Bax and cleaved-caspase-3 were obviously increased (P<0.05). Compared with Infect group, the 72 h cell viability, the protein levels of Bcl-2, LC3-II/I, Atg5, Beclin-1, the mRNA relative expressions and protein phosphorylation levels of JAK2, STAT3 in the Infect+L-NGR1 group and Infect+H-NGR1 group were obviously increased (P<0.05); the contents of IL-1β, TNF-α, IFN-γ, apoptosis rate, the protein levels of Bax and cleaved-Caspase-3 were obviously decreased (P<0.05). Compared with Infect+H-NGR1 group, the 72 h cell viability, the protein levels of Bcl-2, LC3-II/I, Atg5, Beclin-1, the protein phosphorylation levels of JAK2, STAT3 in the Infect+H-NGR1+SD-1029 group were obviously decreased (P<0.05), and the contents of IL-1β, TNF-α, IFN-γ, apoptosis rate, the protein levels of Bax and cleaved-caspase-3 were obviously increased (P<0.05). Conclusions NGR1 can activate the JAK2/STAT3 signaling pathway, promote autophagy of alveolar epithelial cells, and inhibit Kp-induced inflammatory injury and apoptosis of alveolar epithelial cells.