目的 研究髓样细胞分化蛋白(MyD88)抗乙型肝炎病毒(HBV)效应的作用机制。方法 构建MyD88的截短突变体,获得核因子kappa B(NF-κB)超抑制剂IkBa-SR或者NF-κB信号通路激活剂IKKα/IKKβ的表达质粒,分别与HBV复制型质粒瞬时转染Huh7细胞,检测细胞上清液中HBeAg,HBsAg的表达以及胞质中HBV复制中间体DNA的含量,并以NF-κB依赖的荧光素酶报道系统检测它们活化NF-κB的程度。结果 MyD88全长蛋白和2个截短突变体M(1-151)、M(151-296)活化NF-κB的程度与其抑制HBV蛋白以及复制中间体DNA合成的能力相一致。与空载相比,表达NF-κB信号通路激活剂IKKα/IKKβ的质粒共同瞬转细胞后,转染MyD88和HBV表达质粒的细胞中NF-κB的通路明显活化,同时HBV core蛋白的合成显著降低;而NF-κB的超抑制剂IκBα-SR共同瞬转的细胞中core蛋白的表达量显著增加,检测细胞培养上清液中HBeAg和HBsAg及胞质中HBV复制中间体DNA的合成,得到相似结果。结论 NF-κB信号通路的活化在MyD88抑制HBV复制中发挥了关键作用

Objective To investigate the mechanism of MyD88 inhibition of hepatitis B virus (HBV) replication. Methods Two truncated versions of MyD88, M (1-151) and M (152-296) were constructed. Plasmid IκBα-SR encoding NF-κB super-repressor or plasmid IKKα/IKKβ which can strongly activate NF-κB signaling were used. Huh7 cells were transiently transfected with HBV dimer, MyD88 or the above plasmids. Assays of HBsAg, HBeAg, core protein, HBV DNA and NF-κB activation were performed. Results The expression of the full length MyD88, and the two truncated forms, M (1-151) and M (152-296), showed different induction patterns of NF-κB activity; patterns that are consistent with their inhibitory effect on viral protein synthesis and core particle-associated HBV DNA replication. Similarly, the expression of MyD88 resulted in a significant reduction of core protein and the co-expression of IKKα/IKKβ dramatically inhibited the core protein level. Furthermore, the co-expression of IκBα-SR dramatically restored the core protein level. Similar results were also observed for HBeAg, HBsAg and HBV core particle DNA. Conclusion Results from these studies support a role of NF-κB signaling activation in HBV viral replication and suggest a novel mechanism for the inhibition of HBV replication by MyD88. if(document.getElementById('ChDivSummary').innerHTML!=""){CutSpan('ChDivSummary',500);DisplaySpanDiv('ChDivSummary');ClearSummaryOnLoad('SummaryLinkChID','SummaryLinkEnID');}else{CutSpan('EnDivSummary',1000);DisplaySpanDiv('EnDivSummary');ClearSummaryOnLoad('SummaryLinkEnID','SummaryLinkChID');}