Human enterovirus A71(EV-A71)is a major causative agent of hand,foot and mouth disease(HFMD),which poses a significant public health threat,particularly among young children.Mitochondrial antiviral signaling protein(M...Human enterovirus A71(EV-A71)is a major causative agent of hand,foot and mouth disease(HFMD),which poses a significant public health threat,particularly among young children.Mitochondrial antiviral signaling protein(MAVS)and interferon regulatory factor 3(IRF3)are vital proteins for the induction of type I interferons(IFN-I)and downstream interferon-stimulated genes(ISGs)during EVA71 infection.While posttranslational modifications are known to critically influence viral infection processes,the mechanisms by which EV-A71 exploits host deubiquitinases(DUBs)for immune evasion remain poorly understood.In this study,we demonstrated that EV-A71 infection upregulated ubiquitinspecific protease 5(USP5)expression.Knockdown of USP5 not only inhibited EV-A71 replication but also observably increased the production of IFN-I and ISGs.Furthermore,USP5 also regulated the replication of EV-D68 and CVA16 and the production of IFN-I and ISGs.Mechanistically,USP5 physically interacted with MAVS and IRF3 and reduced the K63-linked polyubiquitination of MAVS and IRF3.Conversely,USP5 knockdown increased the K63-linked polyubiquitination of MAVS and IRF3,thereby accelerating the phosphorylation of IRF3 and increasing IFN-I production during EV-A71 infection.Furthermore,pharmacological inhibition of USP5 with the small-molecule inhibitor PR-619 significantly potentiated the antiviral effects of IFN against EV-A71.Collectively,our findings reveal a previously unrecognized role of USP5 in facilitating EV-A71 immune evasion by dampening MAVSand IRF3-mediated antiviral signaling.These insights provide a novel therapeutic avenue for combating EV-A71 infection through targeted modulation of the USP5-IRF3 axis.展开更多
戊型肝炎病毒(Hepatitis E virus,HEV)是导致急性戊肝的主要原因.通过建立基因IV型HEV感染A549细胞模型,研究病毒感染后TLR3信号通路相关因子表达的变化.病毒感染A549细胞后通过实时荧光定量PCR检测IFN-β的mRNA表达量,Western blot分...戊型肝炎病毒(Hepatitis E virus,HEV)是导致急性戊肝的主要原因.通过建立基因IV型HEV感染A549细胞模型,研究病毒感染后TLR3信号通路相关因子表达的变化.病毒感染A549细胞后通过实时荧光定量PCR检测IFN-β的mRNA表达量,Western blot分析磷酸化IRF3(pIRF3)和IKKε蛋白表达水平的变化.结果表明:HEV感染A549细胞后细胞内IFN-β的相对表达水平显著下降,TLR3信号通路介导的pIRF3及IKKε蛋白在病毒感染后表达量显著下降.基因Ⅳ型HEV能够抑制TLR3信号通路介导的IRF3的磷酸化及IKKε蛋白的表达,从而抑制了IFN-β的表达,为进一步研究HEV复制机制和致病机理奠定基础.展开更多
Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to im...Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.展开更多
Interferon regulatory factor （IRF） 7 has been demonstrated to be a master regulator of virus-induced type I interferon production （IFN）, and it plays a central role in the innate immune response against viruses. H...Interferon regulatory factor （IRF） 7 has been demonstrated to be a master regulator of virus-induced type I interferon production （IFN）, and it plays a central role in the innate immune response against viruses. Here, we identified death-associated protein kinase 1 （DAPK1） as an IRF7-interacting protein by tandem affinity purification （TAP）. Viral infection induced DAPKI-IRF7 and DAPKI-IRF3 interactions and overexpression of DAPK1 enhanced virus-induced activation of the interferon-stimulated response element （ISRE） and IFN-p promoters and the expression of the IFNB1 gene. Knockdown of DAPK1 attenuated the induction of IFNB1 and RIG.lexpression triggered by viral infection or I FN-p, and they were enhanced by viral replication. In addition, viral infection or IFN-p treatment induced the expression of DAPK1. IFN-p treatment also activated DAPK1 by decreasing its phosphorylation level at serine 308. Interestingly, the involvement of DAPK1 in virus-induced signaling was independent of its kinase activity. Therefore, our study identified DAPK1 as an important regulator of the cellular antiviral response.展开更多
基金supported by the National Natural Science Foundation of China(32300133 to SZ.and 32100106 to YR)the China Postdoctoral Science Foundation(2023M730965 to SZ.)+3 种基金the Science and Technology Department of Henan Province(232102311103 to SZ.)the Chinese Academy of Sciences(CAS)Youth Innovation Promotion Association(2023351 to YR)the Hubei Province Natural Science Funds(2023AFA008 and 2023AFB582 to YR)the Open project of the State Key Laboratory of Antiviral Drugs,Henan University(FX3020A030002).
文摘Human enterovirus A71(EV-A71)is a major causative agent of hand,foot and mouth disease(HFMD),which poses a significant public health threat,particularly among young children.Mitochondrial antiviral signaling protein(MAVS)and interferon regulatory factor 3(IRF3)are vital proteins for the induction of type I interferons(IFN-I)and downstream interferon-stimulated genes(ISGs)during EVA71 infection.While posttranslational modifications are known to critically influence viral infection processes,the mechanisms by which EV-A71 exploits host deubiquitinases(DUBs)for immune evasion remain poorly understood.In this study,we demonstrated that EV-A71 infection upregulated ubiquitinspecific protease 5(USP5)expression.Knockdown of USP5 not only inhibited EV-A71 replication but also observably increased the production of IFN-I and ISGs.Furthermore,USP5 also regulated the replication of EV-D68 and CVA16 and the production of IFN-I and ISGs.Mechanistically,USP5 physically interacted with MAVS and IRF3 and reduced the K63-linked polyubiquitination of MAVS and IRF3.Conversely,USP5 knockdown increased the K63-linked polyubiquitination of MAVS and IRF3,thereby accelerating the phosphorylation of IRF3 and increasing IFN-I production during EV-A71 infection.Furthermore,pharmacological inhibition of USP5 with the small-molecule inhibitor PR-619 significantly potentiated the antiviral effects of IFN against EV-A71.Collectively,our findings reveal a previously unrecognized role of USP5 in facilitating EV-A71 immune evasion by dampening MAVSand IRF3-mediated antiviral signaling.These insights provide a novel therapeutic avenue for combating EV-A71 infection through targeted modulation of the USP5-IRF3 axis.
文摘戊型肝炎病毒(Hepatitis E virus,HEV)是导致急性戊肝的主要原因.通过建立基因IV型HEV感染A549细胞模型,研究病毒感染后TLR3信号通路相关因子表达的变化.病毒感染A549细胞后通过实时荧光定量PCR检测IFN-β的mRNA表达量,Western blot分析磷酸化IRF3(pIRF3)和IKKε蛋白表达水平的变化.结果表明:HEV感染A549细胞后细胞内IFN-β的相对表达水平显著下降,TLR3信号通路介导的pIRF3及IKKε蛋白在病毒感染后表达量显著下降.基因Ⅳ型HEV能够抑制TLR3信号通路介导的IRF3的磷酸化及IKKε蛋白的表达,从而抑制了IFN-β的表达,为进一步研究HEV复制机制和致病机理奠定基础.
基金supported by the National Natural Science Foundation of China(81730061,81802008)the Guangdong Basic and Applied Basic Research Foundation(2021A1515011272).
文摘Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.
文摘Interferon regulatory factor （IRF） 7 has been demonstrated to be a master regulator of virus-induced type I interferon production （IFN）, and it plays a central role in the innate immune response against viruses. Here, we identified death-associated protein kinase 1 （DAPK1） as an IRF7-interacting protein by tandem affinity purification （TAP）. Viral infection induced DAPKI-IRF7 and DAPKI-IRF3 interactions and overexpression of DAPK1 enhanced virus-induced activation of the interferon-stimulated response element （ISRE） and IFN-p promoters and the expression of the IFNB1 gene. Knockdown of DAPK1 attenuated the induction of IFNB1 and RIG.lexpression triggered by viral infection or I FN-p, and they were enhanced by viral replication. In addition, viral infection or IFN-p treatment induced the expression of DAPK1. IFN-p treatment also activated DAPK1 by decreasing its phosphorylation level at serine 308. Interestingly, the involvement of DAPK1 in virus-induced signaling was independent of its kinase activity. Therefore, our study identified DAPK1 as an important regulator of the cellular antiviral response.
