A Novel Role Of IP6K2 In Regulating Host Cell Death During HSV-1 Virus Infection

Herpes simplex virus-1(HSV-1)is a significant pathogen spread widely across the human population and causes herpes in skin,mucous membrane and nervous system.In addition,there have been numerous reports that HSV-1 is closely related to the pathogenesis of Alzheimer's disease(Alzheimer disease,AD),Parkinson's disease(Parkinson's disease,PD),and so on.In addition,if it is not treated in time,the mortality rate of encephalitis caused by HSV-1 is up to 70%.HSV-1 mainly lurks in nerve cells and occurs in the form of herpes when external pressure and host immunity decline.Because the virus has a strong ability to evade the immune system and its pathogenicity is weak,so the vaccine for the prevention of HSV-1 has not been successfully developed.The replication and maturation of HSV-1 virus in cells depends on various host factors.However,the host factors related to cell death induced by HSV-1 are not well characterized.In recent years,CRISPR/Cas9 system has become a popular tool for gene editing because of its simple and convenient operation.In this study,we chose inositol 6phosphokinase 2(IP6K2),an anti-HSV-1 host gene selected from the CRISPR-library screening,and further explored its role in regulating.IP6K2 can produce inositol pyrophosphate,inositol diphosphate(IP7),selectively affect cell death and apoptosis,and participate in many biological processes.Overexpression of IP6K2 makes cells sensitive to DNA damage,hypoxia,hydrogen peroxide,interferon and other apoptosis stimuli.Some studies have shown that IP6K2 participates in the apoptosis pathway of p53-p21,and regulates p53 and downstream related factors by directly binding p53,thus mediating p53-induced apoptosis.The deletion of IP6K2 gene selectively inhibits p53-mediated apoptosis and inhibits the expression of p21 and other pre-blocking genes by cyclin-dependent kinase,which is beneficial to cell cycle arrest.A variety of IP6K2 gene knockout cell lines were constructed by using CRISPR/Cas9 technology.Our study found that the death rate of IP6K2-deficient cells was significantly lower than that of wild-type cells upon HSV-1 challenges,which revealed that IP6K2 was involved in the regulation of HSV-1-induced mammalian celldeath.The resistance of the virus caused by IP6K2 deletion is not due to blocking on the cell membrane,but rather significantly depends on reducing of virus numbers in the cell.In addition,we found that the viral resistance induced by IP6K2 deletion was not dependent on the interferon pathway in BGC-823 cells.Finally,we found that IP6K2 can play an anti-HSV-1 role by regulating the apoptosis pathway of p53-p21 and its downstream genes.The dependence on IP6K2 for cell death induced by HSV-1 may represent a widespread paradigm for other herpes simplex viruses,and our data suggest that IP6K2 may be used as a new drug target for anti-HSV-1 infection.