PTEN通过下调自噬活性抑制登革病毒2型感染

PTEN inhibits dengue virus type 2 infection by down-regulating autophagy activity

为探讨PTEN、细胞白噬与登革病毒2型(DENV-2)感染之间的关系及可能机制,本研究将DENV-2以不同感染复数(MOI)和不同持续时间感染人脐静脉血管内皮细胞(HUVEC),蛋白免疫印迹法检测PTEN表达及指示细胞自噬的LC3型别转换情况;进一步构建pLenti-PTEN和pLenti-shPTEN表达质粒,包装成慢病毒,感染HUVEC以建立稳定表达细胞系,并检测PTEN过表达及敲低对自噬标记尤其是LC3Ⅱ/LC3Ⅰ比值、DENV-2 capsid蛋白和mRNA水平及子代病毒颗粒感染性的影响。结果显示,PTEN下调可抑制细胞自噬水平,继而降低DENV-2 capsid蛋白表达和子代病毒颗粒释放,提示DENV-2感染HUVEC发生的PTEN蛋白表达下调很可能是宿主细胞本身的一种针对DENV-2感染的保护性反应。

To investigate the role of PTEN protein in dengue virus type 2 （DENV-2） infection and the related autophagy process, human umbilical vein endothelial cells （HUVECs） were challenged with the virus. PTEN expression and autophagy were checked by Western blotting and the level of LC3 type conversions respectively. The pLenti-PTEN and pLenti-shPTEN expression plasmids were constructed and packaged into lentiviruses to establish PTEN- and shPTEN-expressing HUVEC cell lines for further detecting the effects of PTEN overexpression and downexpression on autophagy, especially ratio of LC3Ⅱ/LC3Ⅰ. The effects of PTEN on DENV-2 capsid expression and mRNA level as well as infectivity of progeny viruses were also examined. The data showed that the downexpression of PTEN inhibited autophagy and as a result, reduced the expression of DENV-2 capsid protein and the release of progeny virus particles. It is suggested that the downexpression of PTEN by DENV-2 infection in HUVECs is likely a host protective response against dengue virus infection.