Immune Activation Of Human Cervical Epithelial Cells And Astrocytes Inhibits Herpes Simplex Virus Infection

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Bowman-Birk Inhibitor Suppresses Herpes Simplex Virus Type 2 Infection of Human Cervical Epithelial CellsHerpes simplex virus 2(HSV-2)is an enveloped double-stranded DNA virus,which belongs to Herpesviridae family.HSV-2 is characterized by rapid infection,short replication cycle and destructive damage to target cells.HSV-2 infection was associated with severe genital herpes.In addition,HSV-2 is the cause of neonatal herpes,which is responsible for high morbidity and mortality.More importantly,increasing evidence has shown that HSV-2 infection enhances the risk of HIV acquisition.It is well known that HSV-2 and HIV are lifelong infected pathogens,both of them can be transmitted sexually.Clinically,acyclovir(ACV)and several other nucleoside analogs are used to treat HSV-2 infection due to their suppressive effect on HSV-2 DNA replication and genital ulcerations.However,few evidence has shown that these durgs could restrict HSV-2 transmission in HIVinfected individuals.In addition,due to the frequent use of these antiviral drugs,the emergence of drug resistance has become a severe problem for HSV-2 treatment.Therefore,it is quite necessary and meaningful to search new anti-HSV compounds.The Bowman-Birk inhibitor(BBI),a protease inhibitor derived from soybeans,has been extensively studied in anti-tumor and anti-inflammation research.We recently reported that BBI could activate the intracellular antiviral innate immunity to restrict HIV-1 infection of primary human macrophages.In this study,we thus examined whether BBI has the ability to activate the innate immunity of HSV-2 target cells to inhibit HSV-2 infection.We demonstrated that BBI could potently inhibit HSV-2 replication in human cervical epithelial cells(End1/E6E7).This BBI-mediated HSV-2 inhibitory effect was mainly through these mechanisms:(1)BBI could activate the JAK/STAT pathway and enhance the expression of several antiviral interferon-stimulated genes(ISGs);(2)BBI could inhibit HSV-2-mediated activation of NF-?B and p38 MAPK pathways;(3)BBI reduced HSV-2-mediated cellular ubiquitinated proteins' degradation through suppressing the ubiquitin-proteasome system.Furthermore,we observed that BBI treatment of End1/E6E7 cells upregulated the expression of tight junction proteins.These observations indicate that BBI may have therapeutic potential for the prevention and treatment of HSV-2 infections.Part ? Immune Activation of Human Astrocytes Inhibits Herpes Simplex Virus Type 1 InfectionHuman brain astrocytes are the most abundant type of cells,which are one of the most important part of immune regulatory elements in the brain.HSV-1 belongs to the herpes Simplex Virus family.Like HSV-2,HSV-1 is characterized by the rapid infection cycle and strong replication ability.Usually,HSV-1 is transmitted by respiratory and oral infections in the human body above the waist,such as mouth,cheek,eyes and brain,causing herpes labialis,keratitis,herpes virus encephalitis,etc.In addition,HSV-1 can also trigger genital herpes through oral-genital sexual behavior.Human astrocytes are the target cells of HSV-1.After infection,human astrocytes can restrict HSV-1 replication by inducing apoptisis and producing antiviral factors.Interferon regulator factor 1(IRF1)belongs to IRF family,which plays a key role in regulating a serious of basic processes in cell life.Among 9 human IRFs transcription factors members,IRF1,IRF3,IRF5,IRF7 and IRF9 are considered as the key regulators for the IFNI production.In 1988,IRF1 was firstly proved to bind to interferon(IFN)-? gene regulatory elements.In follow-up studies,IRF3 and IRF7 are two principal factors in modulating IFNs expression,which are responsible for activating IFNs signaling pathway and regulating the production of antiviral IFN-stimulated genes(ISGs).In recent years,intracellular doublestranded DNA(ds DNA)sensing system was widely investigated,and the interaction among IRF3,IRF7 and ds DNA recognition is becoming clearer.Human astrocytes are the largest group glial cells,and they are the primary components for the human blood-brain barrier(BBB).Human astrocytes not only maintain the stability of BBB,but also has a key role in local innate immune response.However,as far as we know,the information and mechanisms about ds DNA immune recognition of human astrocytes are very limited.Our previous studies have demonstrated that human astrocytes express functional Tolllike receptor 3(TLR3),which could be activated by Poly I:C and induce the expression of antiviral factors,including IFN-III.The immune activation of astrocytes mediated by Poly I:C significantly inhibited HSV-1 infection of astrocytes.In this study,we demonstrated that in addition to ds RNA,ds DNA could also activate the innate immunity of astrocytes,induce the expression of IFN-?,IFN-III and antiviral ISGs,and effectively inhibit the infection of HSV-1.Through IRF1 gene knockout technology,we firstly proved that IRF1 played a pivotal role in ds DNA or ds RNA-mediated innate immunity,for the expression of IFNs and antiviral ISGs were regulated by IRF1.These observations indicate that ds DNA and ds RNA could effectively restrict HSV-1 infection by activating the innate immunity in astrocytes through IRF1,which not only highlights the key role of IRF1 in the innate immune regulation,but also provides experimental basis for the development of drugs based on immune activation of HSV target cells.