羊传染性脓疱病毒通过激活PI3K/Akt通路抑制HeLa细胞凋亡

Activation of PI3K/Akt signaling pathway by Orf virus suppresses apoptosis of Hela cells

磷脂酰肌醇3-激酶(PI3K)/Akt信号通路是参与细胞增殖、分化和凋亡调控的重要通路之一,多种病毒可通过对该通路的调控而实现对宿主细胞的感染。作为一种重要的人兽共患传染病病原,羊传染性脓疱病毒(Orf virus,ORFV)被证实能够诱导PI3K/Akt通路的活化。利用PI3K特异性抑制剂LY294002靶向抑制PI3K/Akt通路后,以荧光染色和流式细胞荧光分选技术(FACS)分析该通路的抑制对ORFV感染HeLa细胞凋亡的影响,结果显示抑制PI3K/Akt通路后可使ORFV感染HeLa细胞发生凋亡,该结果表明ORFV感染HeLa细胞产生的凋亡抑制可能与PI3K/Akt通路的激活相关。为进一步明确PI3K/Akt通路介导ORFV感染HeLa细胞凋亡抑制的途径,本研究利用蛋白质印迹法对PI3K/Akt通路3个关键的下游分子GSK-3β、MDM2和Bad的表达情况进行检测,在经PI3K特异性抑制剂LY294002处理后的ORFV感染HeLa细胞中,Bad表达显著上调,而GSK-3β和MDM2的表达无显著变化。结果表明,ORFV通过激活PI3K/Akt/Bad信号通路抑制受感染HeLa细胞发生凋亡。

Various viruses frequently take advantages of the anti-apoptotic effect of the phosphatidylinositol 3-kinase(PI3 K)/Akt pathway to accomplish the viral life cycle.The present study demonstrated for the first time that Orf virus(ORFV),the causative agent of a highly contagious disease in sheep and goats,can induce the activation of PI3 K-Akt pathway in Hela cells.Flow cytometry and immunofluorescence showed that ORFV infection can induce apoptosis when the PI3 K/Akt pathway was blocked by its specific inhibitor LY294002,suggesting that the inhibition of apoptosis in ORFV-infected Hela cells might be related to the activation of PI3 K/Akt pathway.Moreover,the activition of the downstream targets of PI3 K/Akt pathway was further investigated by Western blot.The results showed that the expression of Bad molecule significantly increased in ORFV-infected Hela cells treated with PI3 K specific inhibitor LY294002 comparing to the HeLa cells infected with ORFV,but the expression of GSK-3βand MDM2 did not change.Taken together,these data suggested that ORFV-induced PI3 K/Akt/Bad activation was involved in the regulation of apoptosis blockage.