流感病毒介导的巨噬细胞SIRT1/NF-κB调控机制的研究

Study influenza virus-mediated regulation of SIRT1/NF-κB in macrophages

目的研究巨噬细胞SIRT1-NF-κB信号转导途径在流感病毒感染中的调节机制,为干预流感病毒感染提供新思路。方法以小鼠巨噬细胞Ana.1为研究对象,分别用流感病毒蛋白HA、NP以及NF-κB的抑制剂(PDGF-BB)和激活剂(SC7273)、SIRT1的抑制剂(EX527)和激活剂(SRT1720)处理Ana.1细胞,Western blot观察TNF-α、IL-6、IL-1β、IL-18、SIRT1、NF-κB蛋白相对表达水平,免疫荧光检测SIRT1、NF-κB蛋白在细胞内空间的分布。结果 HA、NP蛋白可诱导Ana.1细胞中SIRT1高表达以及NF-κB的低表达,同时SIRT1与NF-κB在细胞核内都有明显聚集;进一步研究发现,NF-κB被激活时SIRT1表达降低,而NF-κB被抑制时SIRT1表达升高;此外IL-6、IL-1β、IL-18、TNF-α被发现在SIRT1被激活及NF-κB被抑制的情况下表达下调,而在相反情况及流感病毒HA、NP刺激后表达升高。结论流感病毒可能通过HA与NP蛋白激活巨噬细胞SIRT1并进一步抑制NF-κB的表达,形成NF-κB负反馈的现象进而影响机体的炎症反应或免疫应答。

Objective To explore influenza virus-mediated regulation of SIRT1/NF-κB signal transduction pathway toprovide new insight in intervention of influenza virus infection. Methods Mouse macrophage cells, Ana.1, were treated withHA, NP, or inhibitors of NF-κB and SIRT1, PDGF-BB and EX527 respectively, and activators of NF-κB and SIRT1, SC7273 and srt1720 respectively. Protein expression of TNF-α, IL-6, IL-1β, IL-18,SIRT1 and NF-κB was measured by Western-blot, and cellular distribution of SIRT1 and NF-κB proteins was studied by immunofluorescence staining. Results NP andHA up- regulated expression of SIRT1, and down- regulated expression of NF- κB with aggregation of both proteins in thenucleus of Ana.1 cells. Activation or inhibition of NF- κB correlated with down- or up- regulation of SIRT1 respectively.Expression of IL-6,IL-1β,IL-18 and TNF-α decreased by activation of SIRT1 and inhibition of NF-κB, and increased byinhibition of SIRT1 and activation of NF- κB, or stimulation of HA and NP. Conclusion Influenza virus may activatemacrophages SIRT1 by HA and NP and further inhibit the expression of the NF-κB to form NF-κB negative feedback so as tomediate inflammatory and immune response.