scholarly journals GADD45γ Activated Early in the Course of Herpes Simplex Virus 1 Infection Suppresses the Activation of a Network of Innate Immunity Genes

2019 ◽  
Vol 93 (7) ◽  
Author(s):  
Mingmin She ◽  
Haifang Jiang ◽  
Xiaoxiang Chen ◽  
Xiaoqing Chen ◽  
Xianjie Liu ◽  
...  

ABSTRACTThe stress response genes encoding GADD45γ, and to a lesser extent GADD45β, are activated early in infection with herpes simplex virus 1 (HSV-1). Cells that had been depleted of GADD45γ by transfection of short hairpin RNA (shRNA) or in which the gene had been knocked out (ΔGADD45γ) yielded significantly less virus than untreated infected cells. Consistent with lower virus yields, the ΔGADD45γ cells (either uninfected or infected with HSV-1) exhibited significantly higher levels of transcripts of a cluster of innate immunity genes, including those encoding IFI16, IFIT1, MDA5, and RIG-I. Members of this cluster of genes were reported by this laboratory to be activated concurrently with significantly reduced virus yields in cells depleted of LGP2 or HDAC4. We conclude that innate immunity to HSV-1 is normally repressed in unstressed cells and repression appears to be determined by two mechanisms. The first, illustrated here, is through activation by HSV-1 infection of the gene encoding GADD45γ. The second mechanism requires constitutively active expression of LGP2 and HDAC4.IMPORTANCEPrevious studies from our laboratory reported that knockout of some innate immunity genes was associated with increases in the expression of overlapping networks of genes and significant loss of the ability to support the replication of HSV-1; knockout of other genes was associated with decreases in the expression of overlapping networks of genes and had no effect on virus replication. In this report, we document that depletion of GADD45γ reduced virus yields concurrently with significant upregulation of the expression of a cluster of innate immunity genes comprising IFI16, IFIT1, MDA5, and RIG-I. This report differs from the preceding study in an important respect; i.e., the preceding study found no evidence to support the hypothesis that HSV-1 maintained adequate levels of LGP2 or HDAC4 to block upregulation of the cluster of innate immunity genes. We show that HSV-1 causes upregulation of the GADD45γ gene to prevent the upregulation of innate immunity genes.

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Thibaut Deschamps ◽  
Maria Kalamvoki

ABSTRACT The stimulator of interferon (IFN) genes (STING) is a broad antimicrobial factor that restricts herpes simplex virus (HSV) by activating type I interferon and proinflammatory responses upon sensing of foreign DNA. UL46 is one of the most abundant tegument proteins of HSV-1, but a well-established function has yet to be found. We found that the HSV-1 UL46 protein interacts with and colocalizes with STING. A ΔUL46 virus displayed growth defects and activated innate immunity, but both effects were alleviated in STING knockdown cells. UL46 was also required for the inhibition of the 2′,3′-cyclic GMP-AMP (cGAMP)-dependent immune responses during infection. In cells expressing UL46, out of the context of the infection, innate immunity to a ΔICP0 virus was largely compromised, and that permitted ICP0-deficient mutants to replicate. The UL46-expressing cell lines also rescued the defects of the ΔUL46 virus and enhanced wild-type virus infection. The UL46-expressing cell lines did not activate interferon-stimulated gene (ISG) transcription following treatment with the noncanonical cyclic dinucleotide 2′,3′-cGAMP, suggesting that the STING pathway may be compromised. Indeed, we found that both proteins STING and IFI16 were eliminated in cells constitutively expressing UL46 and that the accumulation of their transcripts was blocked. Finally, we demonstrated that UL46 via its N terminus binds to STING and, via its C terminus, to TBK1. These interactions appear to modulate the functions of STING during HSV-1 infection. Taken together, our studies describe a novel function for one of the least-studied proteins of HSV, the tegument protein UL46, and that function involves the evasion of foreign DNA-sensing pathways. IMPORTANCE Herpes simplex virus 1 (HSV-1) afflicts 80% of the population worldwide, causing various diseases. After initial infection, the virus establishes latent reservoirs in sensory neurons and persists for life. Here we describe novel interactions between HSV-1 and the DNA sensor STING. We found that (i) HSV-1 tegument protein UL46 interacts with and colocalizes with STING; (ii) UL46 expressed out of the context of the infection blocks type I interferon triggered by STING stimuli, through the elimination of STING and of interferon-inducible protein 16 (IFI16); (iii) a ΔUL46 virus displayed growth defects, which were rescued in STING knockdown cells; (iv) the ΔUL46 virus failed to block innate immunity triggered by ligands of STING such as 2′,3′-cGAMP and also activated IFN-β and ISG expression; and (v) UL46 binds to both STING and TBK1 through different domains. We conclude that UL46 counteracts the actions of STING during HSV-1 infection.


2003 ◽  
Vol 77 (11) ◽  
pp. 6178-6187 ◽  
Author(s):  
Brunella Taddeo ◽  
Audrey Esclatine ◽  
Weiran Zhang ◽  
Bernard Roizman

ABSTRACT The accumulation of cellular transcripts from cells infected with herpes simplex virus 1 (HSV-1) as measured with the aid of Affymetrix microchips has been reported elsewhere. Among these transcripts were genes that respond to stress and that could have a noxious effect on viral replication. We have selected the stress-inducible cellular gene encoding the immediate-early response protein IEX-1 to verify and determine the significance of the accumulation of these transcripts in infected cells. We report that we verified the increase in accumulation of IEX-1 transcripts after infection by Northern analyses and real-time PCR. These transcripts reach peak levels between 3 and 7 h after infection and decrease thereafter. However, IEX-1 protein was detected in cells 1 h after infection but not at later intervals. Studies designed to elucidate the failure of IEX-1 protein to be synthesized revealed the following points. (i) IEX-1 RNA transported to the cytoplasm after 1 h of infection consisted of at least two populations, a partially degraded population and a population consisting of unspliced IEX-1 RNA. Neither of these RNAs could translate the authentic IEX-1 protein. (ii) The partially degraded IEX-1 RNA was not detected in the cytoplasm of cells infected with a mutant virus lacking the UL41 gene encoding the virion host shutoff protein (vhs). Although degradation of RNA mediated by vhs was reported to be 5′ to 3′, the partially degraded IEX-1 RNA lacked the 3′ sequences rather than the 5′ sequences. (iii) The unspliced pre-RNA form containing the IEX-1 intron sequences was detected in the cytoplasm of cell infected with wild-type virus but not in those infected with a mutant lacking the α27 gene encoding the infected cell protein No. 27. (iv) Overexpression of IEX-1 protein by transduction of the gene prior to infection with 1 PFU of HSV-1 per cell had no effect on the accumulation of late genes and virus yield. We conclude that the failure of IEX-1 to express its protein reflects the numerous mechanisms by which the virus thwarts the cells from expressing its genes after infection.


2018 ◽  
Vol 92 (15) ◽  
Author(s):  
Jian Huang ◽  
Hongjuan You ◽  
Chenhe Su ◽  
Yangxin Li ◽  
Shunhua Chen ◽  
...  

ABSTRACTCytosolic DNA arising from intracellular pathogens is sensed by cyclic GMP-AMP synthase (cGAS) and triggers a powerful innate immune response. However, herpes simplex virus 1 (HSV-1), a double-stranded DNA virus, has developed multiple mechanisms to attenuate host antiviral machinery and facilitate viral infection and replication. In the present study, we found that HSV-1 tegument protein VP22 acts as an inhibitor of cGAS/stimulator of interferon genes (cGAS/STING)-mediated production of interferon (IFN) and its downstream antiviral genes. Our results showed that ectopic expression of VP22 decreased cGAS/STING-mediated IFN-β promoter activation and IFN-β production. Infection with wild-type (WT) HSV-1, but not VP22-deficient virus (ΔVP22), inhibited immunostimulatory DNA (ISD)-induced activation of the IFN signaling pathway. Further study showed that VP22 interacted with cGAS and inhibited the enzymatic activity of cGAS. In addition, stable knockdown of cGAS facilitated the replication of ΔVP22 virus but not the WT. In summary, our findings indicate that HSV-1 VP22 acts as an antagonist of IFN signaling to persistently evade host innate antiviral responses.IMPORTANCEcGAS is very important for host defense against viral infection, and many viruses have evolved ways to target cGAS and successfully evade the attack by the immune system of their susceptible host. This study demonstrated that HSV-1 tegument protein VP22 counteracts the cGAS/STING-mediated DNA-sensing antiviral innate immunity signaling pathway by inhibiting the enzymatic activity of cGAS. The findings in this study will expand our understanding of the interaction between HSV-1 replication and the host DNA-sensing signaling pathway.


2013 ◽  
Vol 87 (23) ◽  
pp. 12814-12827 ◽  
Author(s):  
Shuai Wang ◽  
Kezhen Wang ◽  
Rongtuan Lin ◽  
Chunfu Zheng

Viral infection initiates a series of signaling cascades that lead to the transcription of interferons (IFNs), finally inducing interferon-stimulated genes (ISGs) to eliminate viruses. Viruses have evolved a variety of strategies to modulate host IFN-mediated immune responses. Herpes simplex virus 1 (HSV-1) US3, a Ser/Thr kinase conserved in alphaherpesviruses, was previously reported to counteract host innate immunity; however, the molecular mechanism is elusive. In this study, we report that US3 blocks IFN-β production by hyperphosphorylating IFN regulatory factor 3 (IRF3). Ectopic expression of US3 protein significantly inhibited Sendai virus (SeV)-mediated activation of IFN-β and IFN-stimulated response element (ISRE) promoters and the transcription of IFN-β, ISG54, and ISG56. US3 was also shown to block SeV-induced dimerization and nuclear translocation of IRF3. The kinase activity was indispensable for its inhibitory function, as kinase-dead (KD) US3 mutants K220M and D305A could not inhibit IFN-β production. Furthermore, US3 interacted with and hyperphosphorylated IRF3 at Ser175 to prevent IRF3 activation. Finally, the US3 KD mutant viruses were constructed and denoted K220M or D305A HSV-1, respectively. Cells and mice infected with both mutant viruses produced remarkably larger amounts of IFN-β than those infected with wild-type HSV-1. For the first time, these findings provide convincing evidence that US3 hyperphosphorylates IRF3, blocks the production of IFN-β, and subverts host innate immunity.


Author(s):  
Huifang Zhu ◽  
Chunfu Zheng

SUMMARY Herpes simplex virus 1 (HSV-1) is very successful in establishing acute and latent infections in humans by counteracting host antiviral innate immune responses. HSV-1 has evolved various strategies to evade host antiviral innate immunity and some cellular survival-associated pathways. Since there is still no vaccine available for HSV-1, a continuous update of information regarding the interaction between HSV-1 infection and the host antiviral innate immunity will provide novel insights to develop new therapeutic strategies for HSV-1 infection and its associated diseases. Here, we update recent studies about how HSV-1 evades the host antiviral innate immunity, specifically how HSV-1 proteins directly or indirectly target the adaptors in the antiviral innate immunity signaling pathways to downregulate the signal transduction. Additionally, some classical intracellular stress responses, which also play important roles in defense of viral invasion, will be discussed here. With a comprehensive review of evasion mechanisms of antiviral innate immunity by HSV-1, we will be able to develop potential new targets for therapies and a possible vaccine against HSV-1 infections.


Author(s):  
Z. Hong Zhou ◽  
Jing He ◽  
Joanita Jakana ◽  
J. D. Tatman ◽  
Frazer J. Rixon ◽  
...  

Herpes simplex virus-1 (HSV-1) is a ubiquitous virus which is implicated in diseases ranging from self-curing cold sores to life-threatening infections. The 2500 Å diameter herpes virion is composed of a glycoprotein spike containing, lipid envelope, enclosing a protein layer (the tegument) in which is embedded the capsid (which contains the dsDNA genome). The B-, and A- and C-capsids, representing different morphogenetic stages in HSV-1 infected cells, are composed of 7, and 5 structural proteins respectively. The three capsid types are organized in similar T=16 icosahedral shells with 12 pentons, 150 hexons, and 320 connecting triplexes. Our previous 3D structure study at 26 Å revealed domain features of all these structural components and suggested probable locations for the outer shell proteins, VP5, VP26, VP19c and VP23. VP5 makes up most of both pentons and hexons. VP26 appeared to bind to the VP5 subunit in hexon but not to that in penton.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Shahnazaryan ◽  
Rana Khalil ◽  
Claire Wynne ◽  
Caroline A. Jefferies ◽  
Joan Ní Gabhann-Dromgoole ◽  
...  

AbstractHerpes simplex keratitis (HSK), caused by herpes simplex virus type 1 (HSV-1) infection, is the commonest cause of infectious blindness in the developed world. Following infection the virus is initially suspended in the tear film, where it encounters a multi-pronged immune response comprising enzymes, complement, immunoglobulins and crucially, a range of anti-viral and pro-inflammatory cytokines. However, given that HSV-1 can overcome innate immune responses to establish lifelong latency throughout a susceptible individual’s lifetime, there is significant interest in understanding the mechanisms employed by HSV-1 to downregulate the anti-viral type I interferon (IFN) mediated immune responses. This study aimed to investigate the interactions between infected cell protein (ICP)0 and key elements of the IFN pathway to identify possible novel targets that contribute to viral immune evasion. Reporter gene assays demonstrated the ability of ICP0 to inhibit type I IFN activity downstream of pathogen recognition receptors (PRRs) which are known to be involved in host antiviral defences. Further experiments identified interferon regulatory factor (IRF)7, a driver of type I IFN, as a potential target for ICP0. These findings increase our understanding of the pathogenesis of HSK and suggest IRF7 as a potential therapeutic target.


Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 196
Author(s):  
Sara Artusi ◽  
Emanuela Ruggiero ◽  
Matteo Nadai ◽  
Beatrice Tosoni ◽  
Rosalba Perrone ◽  
...  

The herpes simplex virus 1 (HSV-1) genome is extremely rich in guanine tracts that fold into G-quadruplexes (G4s), nucleic acid secondary structures implicated in key biological functions. Viral G4s were visualized in HSV-1 infected cells, with massive virus cycle-dependent G4-formation peaking during viral DNA replication. Small molecules that specifically interact with G4s have been shown to inhibit HSV-1 DNA replication. We here investigated the antiviral activity of TMPyP4, a porphyrin known to interact with G4s. The analogue TMPyP2, with lower G4 affinity, was used as control. We showed by biophysical analysis that TMPyP4 interacts with HSV-1 G4s, and inhibits polymerase progression in vitro; in infected cells, it displayed good antiviral activity which, however, was independent of inhibition of virus DNA replication or entry. At low TMPyP4 concentration, the virus released by the cells was almost null, while inside the cell virus amounts were at control levels. TEM analysis showed that virus particles were trapped inside cytoplasmatic vesicles, which could not be ascribed to autophagy, as proven by RT-qPCR, western blot, and immunofluorescence analysis. Our data indicate a unique mechanism of action of TMPyP4 against HSV-1, and suggest the unprecedented involvement of currently unknown G4s in viral or antiviral cellular defense pathways.


2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Fumio Maeda ◽  
Jun Arii ◽  
Yoshitaka Hirohata ◽  
Yuhei Maruzuru ◽  
Naoto Koyanagi ◽  
...  

ABSTRACT Upon herpes simplex virus 1 (HSV-1) infection, the CD98 heavy chain (CD98hc) is redistributed around the nuclear membrane (NM), where it promotes viral de-envelopment during the nuclear egress of nucleocapsids. In this study, we attempted to identify the factor(s) involved in CD98hc accumulation and demonstrated the following: (i) the null mutation of HSV-1 UL34 caused specific dispersion throughout the cytoplasm of CD98hc and the HSV-1 de-envelopment regulators, glycoproteins B and H (gB and gH); (ii) as observed with CD98hc, gB, and gH, wild-type HSV-1 infection caused redistribution of the endoplasmic reticulum (ER) markers calnexin and ERp57 around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of these markers; (iii) the ER markers colocalized efficiently with CD98hc, gB, and gH in the presence and absence of UL34 in HSV-1-infected cells; (iv) at the ultrastructural level, wild-type HSV-1 infection caused ER compression around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of the ER; and (v) the UL34-null mutation significantly decreased the colocalization efficiency of lamin protein markers of the NM with CD98hc and gB. Collectively, these results indicate that HSV-1 infection causes redistribution of the ER around the NM, with resulting accumulation of ER-associated CD98hc, gB, and gH around the NM and that UL34 is required for ER redistribution, as well as for efficient recruitment to the NM of the ER-associated de-envelopment factors. Our study suggests that HSV-1 induces remodeling of the global ER architecture for recruitment of regulators mediating viral nuclear egress to the NM. IMPORTANCE The ER is an important cellular organelle that exists as a complex network extending throughout the cytoplasm. Although viruses often remodel the ER to facilitate viral replication, information on the effects of herpesvirus infections on ER morphological integrity is limited. Here, we showed that HSV-1 infection led to compression of the global ER architecture around the NM, resulting in accumulation of ER-associated regulators associated with nuclear egress of HSV-1 nucleocapsids. We also identified HSV-1 UL34 as a viral factor that mediated ER remodeling. Furthermore, we demonstrated that UL34 was required for efficient targeting of these regulators to the NM. To our knowledge, this is the first report showing that a herpesvirus remodels ER global architecture. Our study also provides insight into the mechanism by which the regulators for HSV-1 nuclear egress are recruited to the NM, where this viral event occurs.


2012 ◽  
Vol 86 (16) ◽  
pp. 8592-8601 ◽  
Author(s):  
Charlotte Mahiet ◽  
Ayla Ergani ◽  
Nicolas Huot ◽  
Nicolas Alende ◽  
Ahmed Azough ◽  
...  

Herpes simplex virus 1 (HSV-1) is a human pathogen that leads to recurrent facial-oral lesions. Its 152-kb genome is organized in two covalently linked segments, each composed of a unique sequence flanked by inverted repeats. Replication of the HSV-1 genome produces concatemeric molecules in which homologous recombination events occur between the inverted repeats. This mechanism leads to four genome isomers (termed P, IS, IL, and ILS) that differ in the relative orientations of their unique fragments. Molecular combing analysis was performed on DNA extracted from viral particles and BSR, Vero, COS-7, and Neuro-2a cells infected with either strain SC16 or KOS of HSV-1, as well as from tissues of experimentally infected mice. Using fluorescence hybridization, isomers were repeatedly detected and distinguished and were accompanied by a large proportion of noncanonical forms (40%). In both cell and viral-particle extracts, the distributions of the four isomers were statistically equivalent, except for strain KOS grown in Vero and Neuro-2a cells, in which P and IS isomers were significantly overrepresented. In infected cell extracts, concatemeric molecules as long as 10 genome equivalents were detected, among which, strikingly, the isomer distributions were equivalent, suggesting that any such imbalance may occur during encapsidation.In vivo, for strain KOS-infected trigeminal ganglia, an unbalanced distribution distinct from the onein vitrowas observed, along with a considerable proportion of noncanonical assortment.


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