TRIM21 Aggravates Herpes Simplex Virus Epithelial Keratitis by Attenuating STING-IRF3-Mediated Type I Interferon Signaling

ABSTRACT In spite of several decades of research focused on understanding the biology of human herpes simplex virus 1 (HSV-1), no tool has been developed to study its genome in a high-throughput fashion. Here, we describe the creation of a transposon insertion mutant library of the HSV-1 genome. Using this tool, we aimed to identify novel viral regulators of type I interferon (IFN-I). HSV-1 evades the host immune system by encoding viral proteins that inhibit the type I interferon response. Applying differential selective pressure, we identified the three strongest viral IFN-I regulators in HSV-1. We report that the viral polymerase processivity factor UL42 interacts with the host transcription factor IFN regulatory factor 3 (IRF-3), inhibiting its phosphorylation and downstream beta interferon (IFN-β) gene transcription. This study represents a proof of concept for the use of high-throughput screening of the HSV-1 genome in investigating viral biology and offers new targets both for antiviral therapy and for oncolytic vector design. IMPORTANCE This work is the first to report the use of a high-throughput mutagenesis method to study the genome of HSV-1. We report three novel viral proteins potentially involved in regulating the host type I interferon response. We describe a novel mechanism by which the viral protein UL42 is able to suppress the production of beta interferon. The tool we introduce in this study can be used to study the HSV-1 genome in great detail to better understand viral gene functions.

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Unique Type I Interferon, Expansion/Survival Cytokines, and JAK/STAT Gene Signatures of Multifunctional Herpes Simplex Virus-Specific Effector Memory CD8+ TEM Cells Are Associated with Asymptomatic Herpes in Humans

Journal of Virology ◽

10.1128/jvi.01882-18 ◽

2018 ◽

Vol 93 (4) ◽

Cited By ~ 9

Author(s):

Hawa Vahed ◽

Anshu Agrawal ◽

Ruchi Srivastava ◽

Swayam Prakash ◽

Pierre-Gregoire A. Coulon ◽

...

Keyword(s):

T Cells ◽

Herpes Simplex Virus ◽

Herpes Simplex ◽

T Cell ◽

Type I Interferon ◽

Effector Memory ◽

Type I ◽

Gene Signatures ◽

Specific Effector ◽

Simplex Virus

ABSTRACT A large proportion of the world population harbors herpes simplex virus 1 (HSV-1), a major cause of infectious corneal blindness. HSV-specific CD8+ T cells protect from herpesvirus infection and disease. However, the genomic, phenotypic, and functional characteristics of CD8+ T cells associated with the protection seen in asymptomatic (ASYMP) individuals, who, despite being infected, never experienced any recurrent herpetic disease, remains to be fully elucidated. In this investigation, we compared the phenotype, function, and level of expression of a comprehensive panel of 579 immune genes of memory CD8+ T cells, sharing the same HSV-1 epitope specificities, and freshly isolated peripheral blood from well-characterized cohorts of protected ASYMP and nonprotected symptomatic (SYMP) individuals, with a history of numerous episodes of recurrent herpetic disease, using the high-throughput digital NanoString nCounter system and flow cytometry. Interestingly, our results demonstrated that memory CD8+ T cells from ASYMP individuals expressed a unique set of genes involved in expansion and survival, type I interferon (IFN-I), and JAK/STAT pathways. Frequent multifunctional HSV-specific effector memory CD62Llow CD44high CD8+ TEM cells were detected in ASYMP individuals compared to more of monofunctional central memory CD62Lhigh CD44high CD8+ TCM cells in SYMP individuals. Shedding light on the genotype, phenotype, and function of antiviral CD8+ T cells from “naturally protected” ASYMP individuals will help design future T-cell-based ocular herpes immunotherapeutic vaccines. IMPORTANCE A staggering number of the world population harbors herpes simplex virus 1 (HSV-1) potentially leading to blinding recurrent herpetic disease. While the majority are asymptomatic (ASYMP) individuals who never experienced any recurrent herpetic disease, symptomatic (SYMP) individuals have a history of numerous episodes of recurrent ocular herpetic disease. This study elucidates the phenotype, the effector function, and the gene signatures of memory CD8+ T-cell populations associated with protection seen in ASYMP individuals. Frequent multifunctional HSV-specific effector memory CD8+ TEM cells were detected in ASYMP individuals. In contrast, nonprotected SYMP individuals had more central memory CD8+ TCM cells. The memory CD8+ TEM cells from ASYMP individuals expressed unique gene signatures characterized by higher levels of type I interferon (IFN), expansion and expansion/survival cytokines, and JAK/STAT pathways. Future studies on the genotype, phenotype, and function of antiviral CD8+ T cells from “naturally protected” ASYMP individuals will help in the potential design of T-cell-based ocular herpes vaccines.

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The Latency-Associated Transcript Inhibits Apoptosis via Downregulation of Components of the Type I Interferon Pathway during Latent Herpes Simplex Virus 1 Ocular Infection

Journal of Virology ◽

10.1128/jvi.00103-19 ◽

2019 ◽

Vol 93 (10) ◽

Cited By ~ 7

Author(s):

Kati Tormanen ◽

Sariah Allen ◽

Kevin R. Mott ◽

Homayon Ghiasi

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Type I Interferon ◽

Gene Expression Pattern ◽

Ocular Infection ◽

Transcriptional Level ◽

Type I ◽

Human Pathology ◽

Simplex Virus ◽

Hsv 1

ABSTRACTThe herpes simplex virus (HSV-1) latency-associated transcript (LAT) has been shown to inhibit apoptosis via inhibiting activation of proapoptotic caspases. However, the mechanism of LAT control of apoptosis is unclear, because LAT is not known to encode a functional protein, and the LAT transcript is found largely in the nucleus. We hypothesized that LAT inhibits apoptosis by regulating expression of genes that control apoptosis. Consequently, we sought to establish the molecular mechanism of antiapoptosis functions of LAT at a transcriptional level during latent HSV-1 ocular infection in mice. Our results suggest the following. (i) LAT likely inhibits apoptosis via upregulation of several components of the type I interferon (IFN) pathway. (ii) LAT does not inhibit apoptosis via the caspase cascade at a transcriptional level or via downregulating Toll-like receptors (TLRs). (iii) The mechanism of LAT antiapoptotic effect is distinct from that of the baculovirus inhibitor of apoptosis (cpIAP) because replacement of LAT with the cpIAP gene resulted in a different gene expression pattern than in either LAT+or LAT−viruses. (iv) Replacement of LAT with the cpIAP gene does not cause upregulation of CD8 or markers of T cell exhaustion despite their having similar levels of latency, further supporting that LAT and cpIAP function via distinct mechanisms.IMPORTANCEThe HSV-1 latency reactivation cycle is the cause of significant human pathology. The HSV-1 latency-associated transcript (LAT) functions by regulating latency and reactivation, in part by inhibiting apoptosis. However, the mechanism of this process is unknown. Here we show that LAT likely controls apoptosis via downregulation of several components in the JAK-STAT pathway. Furthermore, we provide evidence that immune exhaustion is not caused by the antiapoptotic activity of the LAT.

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