Research On The Mechanism Of Host Protein S100A6 Inhibiting Zika Virus Replication

Background:Zika virus(ZIKV)is a mosquito-borne arbovirus,and its infection results in ZIKV diseases.In recent years,ZIKV has erupted in many countries,triggered large-scale outbreaks over the world In 2016,the World Health Organization declared ZIKV infection a global public health emergency.Maternal infection may cause serious complications such as neonatal microcephaly and neurological defects.There is still no clinically approved specific vaccine or drug for ZIKV infection.Therefore,it is urgent to better understand the pathogenesis of Zika virus and host-virus interactions.S100A6 is a member of S100 protein family.It can regulate a series of different cellular processes,and can interact with a variety of target proteins.Studies have found that S100A6 expression is up-regulated in response to various stimuli.The intracellular virus has to rely on host proteins to complete the replication and proliferation process.A study has screened that S100A6 protein may function as a host-dependent factor in the process of Flavivirus infection.Methods:The expression of S100A6 in host cells was detected by western blotting(WB)at different time points or with different multiplication of infections(MOIs)of ZIKV The effects of host S100A6 on ZIKV replication,nonstructural protein 3(NS3)expression level and transcription level were detected by WB,qPCR and immunofluorescence assay(IFA).Proteasome inhibitors and lysosomal inhibitors were used to explore the degradation pathway of NS3 by S100A6.The interaction and co-localization of S100A6 and NS3 were detected by co-immunoprecipitation(Co-IP)and IFA.Results:ZIKV infection could increase the expression level of S100A6 in a dose-dependent and time-dependent manner.After S100A6 overexpression in Hela cells and followed by ZIKV infection,it was found that S100A6 had no effect on the binding and entry process of the virus,but significantly inhibited the replication of the virus.On the contrary,S100A6 knockdown led to a significant increase in viral replication.Moreover,S100A6 protein could bind and degrade ZIKV NS3,but did not affect the transcription level of NS3.The use of lysosomal inhibitor NH4Cl significantly reversed the down-regulated NS3 protein level mediated by S100A6,which indicated that S100A6 degraded NS3 through the lysosomal pathway.Conclusion:The host protein S100A6 level was up-regulated after ZIKV infection,and S100A6 may act as a host restriction factor to specifically degrade the ZIKV NS3 through interaction with NS3 to inhibit virus replication,and played an antiviral role.