Heat-shock Protein 90? Is Involved In Maintaining The Stability Of VP16 And VP16-mediated Transactivation Of ? Genes From Herpes Simplex Virus-1

Research background and Aim: Herpes simplex virus type 1(HSV-1)is an important human pathogenic virus.Given that the singleness of clinically used drugs and the emergence of drug resistant virus,it is urgent for us to develop novel antiviral targets.Complement of virus life cycle depend on host factors,thus these factors are promising therapeutic targets and in-depth study of host-virus interaction contributes to develop novel anti-virus drug.Our prior studies indicated that Hsp90 inhibitors exhibited great antivirus activity against HSV-1 in vitro and in vivo,while the detailed mechanisms remain uncertain.Our previous study also found that Hsp90 inhibition suppressed the expression of HSV-1 ? genes while the role of the major specific Hsp90 isoform in HSV-1 life cycle and the relationship between Hsp90 and ? genes expression remain unclear.As initiated genes of HSV-1 genes,? genes are significant for the complement of HSV-1 life cycle.Therefore,out studies focused on exploring the detailed regulation mechanisms that Hsp90 functions in HSV-1 ? genes,which will provide the theoretical foundation for the understanding and development of Hsp90 associated pathways as novel anti-HSV-1 therapeutic drugs.Methods and Results: In this project,we explored the specific isoform of Hsp90 that functioned in the HSV-1 life cycle and the isoform's function in HSV-1 ? genes transcription with dual luciferase and plaque reduction assay via combining with Hsp90 inhibitors,gene silence and overexpression.Furthermore,we determined the detailed molecular mechanisms that Hsp90 was involved in the regulation of HSV-1 ? genes transcription with immunoprecipitation and westernblot assays,then further determined the antivirus activity and potential mechanism of with the gels containing AT533 in HSV-1 infection mediated mouse zosteriform model.Collectively,our study focused on comprehensively determining both the role and detailed mechanisms of Hsp90 in HSV-1 ? genes transcription in vitro and in vivo.Brief results were listed as follows: 1.Hsp90? is the major isoform that functioned in HSV-1 life cycle and participated in the modulation of HSV-1 ? genes,but not Hsp90?;2.VP16 can be degraded in the context of Hsp90 inhibition and Hsp90? silencing,while VP16 restores the suppression of HSV-1 ? genes level and ? genes promoters activity that Hsp90? silence-mediated.3.VP16 interacts with Hsp90? via its conserved core domain;4.Autophagy inhibition blocks Hsp90 inhibition mediated VP16 degradation wile proteasome inhibitor cannot produce such effect;5.The truncated mutant of VP16 that failed to interact with VP16 cannot be degraded by Hsp90 inhibition and Hsp90? silence;6.Gels containing AT533 significantly improve the HSV-1 infection mediated zosteriform mice model,and reduce the level of HSV-1 ? genes and VP16 protein.Conclusion and Significance: Hsp90? is the dominant Hsp90 isoform functions in HSV-1 infection.Hsp90? interacts with VP16 via the conserved core domain within VP16 then maintains the stability of VP16 to regulate the transcription of HSV-1 ? genes that VP16 meidates.In detail,Hsp90 inhibition disrupts the interaction between Hsp90? and VP16 and activates the autophagy pathway simultaneously then leads to the degradation of VP16.Consistently,in the HSV-1 infection mediated zosteriform mice model,gels containing different concentration of AT533 treatment significantly reduce the level of HSV-1 ? genes and VP16 proteins,exhibiting the great activity of anti-HSV-1.Our study thus provides new insights into the mechanisms by which Hsp90? facilitates the transactivation of HSV-1 ? genes and viral replication and highlights a novel strategy to develop optimizing inhibitors targeting the interaction between Hsp90? and VP16 to reduce toxicity of Hsp90 inhibitors,a major challenge in clinical application of Hsp90 inhibitors.