1
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Duan Y, Sun L, Li Q. Herpes Simplex Virus 1 MicroRNAs: An Update. Intervirology 2023; 66:97-110. [PMID: 37285807 PMCID: PMC10389796 DOI: 10.1159/000531348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 05/24/2023] [Indexed: 06/09/2023] Open
Abstract
BACKGROUND Herpes simplex virus 1 (HSV-1), an important human pathogen, is capable of latent infection in neurons and productive (lytic) infection in other tissue cells. Once infected with HSV-1, the immune system of the organism cannot eliminate the virus and carries it lifelong. HSV-1 possesses approximately 150 kb of double-stranded linear genomic DNA and can encode at least 70 proteins and 37 mature microRNAs (miRNAs) derived from 18 precursor miRNAs (pre-miRNAs). SUMMARY These HSV-1-encoded miRNAs are widely involved in multiple processes in the life cycle of the virus and the host cell, including viral latent and lytic infection, as well as host cell immune signaling, proliferation, and apoptosis. KEY MESSAGE In this review, we focused primarily on recent advances in HSV-1-encoded miRNA expression, function, and mechanism, which may provide new research ideas and feasible research methods systemically and comprehensively.
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Affiliation(s)
- Yongzhong Duan
- Academy of Biomedical Engineering, Kunming Medical University, Kunming, China,
| | - Le Sun
- Basic Medical College, Kunming Medical University, Kunming, China
| | - Qihan Li
- Department of Viral Immunology, Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
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2
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Hazlett LD, Xu S, Somayajulu M, McClellan SA. Host-microbe interactions in cornea. Ocul Surf 2023; 28:413-423. [PMID: 34619389 PMCID: PMC8977393 DOI: 10.1016/j.jtos.2021.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/23/2021] [Accepted: 09/26/2021] [Indexed: 11/23/2022]
Abstract
Corneal infections result through interaction between microbes and host innate immune receptors. Damage to the cornea occurs as a result of microbial virulence factors and is often exacerbated by lack of a controlled host immune response; the latter contributing to bystander damage to corneal structure. Understanding mechanisms involved in host microbial interactions is critical to development of novel therapeutic targets, ultimate control of microbial pathogenesis, and restoration of tissue homeostasis. Studies on these interactions continue to provide exciting findings directly related to this ultimate goal.
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Affiliation(s)
- Linda D Hazlett
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
| | - Shunbin Xu
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Mallika Somayajulu
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Sharon A McClellan
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, 48201, USA
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3
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Deng J, Wu Z, Liu J, Ji Q, Ju C. The Role of Latency-Associated Transcripts in the Latent Infection of Pseudorabies Virus. Viruses 2022; 14:v14071379. [PMID: 35891360 PMCID: PMC9320458 DOI: 10.3390/v14071379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 11/16/2022] Open
Abstract
Pseudorabies virus (PRV) can cause neurological, respiratory, and reproductive diseases in pigs and establish lifelong latent infection in the peripheral nervous system (PNS). Latent infection is a typical feature of PRV, which brings great difficulties to the prevention, control, and eradication of pseudorabies. The integral mechanism of latent infection is still unclear. Latency-associated transcripts (LAT) gene is the only transcriptional region during latent infection of PRV which plays the key role in regulating viral latent infection and inhibiting apoptosis. Here, we review the characteristics of PRV latent infection and the transcriptional characteristics of the LAT gene. We also analyzed the function of non-coding RNA (ncRNA) produced by the LAT gene and its importance in latent infection. Furthermore, we provided possible strategies to solve the problem of latent infection of virulent PRV strains in the host. In short, the detailed mechanism of PRV latent infection needs to be further studied and elucidated.
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4
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Yun H, Yin XT, Stuart PM, St Leger AJ. Sensory Nerve Retraction and Sympathetic Nerve Innervation Contribute to Immunopathology of Murine Recurrent Herpes Stromal Keratitis. Invest Ophthalmol Vis Sci 2022; 63:4. [PMID: 35103749 PMCID: PMC8819360 DOI: 10.1167/iovs.63.2.4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose Herpes stromal keratitis (HSK) represents a spectrum of pathologies which is caused by herpes simplex virus type 1 (HSV-1) infection and is considered a leading cause of infectious blindness. HSV-1 infects corneal sensory nerves and establishes latency in the trigeminal ganglion (TG). Recently, retraction of sensory nerves and replacement with “unsensing” sympathetic nerves was identified as a critical contributor of HSK in a mouse model where corneal pathology is caused by primary infection. This resulted in the loss of blink reflex, corneal desiccation, and exacerbation of inflammation leading to corneal opacity. Despite this, it was unclear whether inflammation associated with viral reactivation was sufficient to initiate this cascade of events. Methods We examined viral reactivation and corneal pathology in a mouse model with recurrent HSK by infecting the cornea with HSV-1 (McKrae) and transferring (intravenous [IV]) human sera to establish primary infection without discernible disease and then exposed the cornea to UV-B light to induce viral reactivation. Results UV-B light induced viral reactivation from latency in 100% of mice as measured by HSV-1 antigen deposition in the cornea. Further, unlike conventional HSK models, viral reactivation resulted in focal retraction of sensory nerves and corneal opacity. Dependent on CD4+ T cells, inflammation foci were innervated by sympathetic nerves. Conclusions Collectively, our data reveal that sectoral corneal sensory nerve retraction and replacement of sympathetic nerves were involved in the progressive pathology that is dependent on CD4+ T cells after viral reactivation from HSV-1 latency in the UV-B induced recurrent HSK mouse model.
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Affiliation(s)
- Hongmin Yun
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Xiao-Tang Yin
- Department of Ophthalmology, Saint Louis University, St. Louis, Missouri, United States
| | - Patrick M Stuart
- Department of Ophthalmology, Saint Louis University, St. Louis, Missouri, United States
| | - Anthony J St Leger
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.,Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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5
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Zhang Y, Zeng LS, Wang J, Cai WQ, Cui W, Song TJ, Peng XC, Ma Z, Xiang Y, Cui SZ, Xin HW. Multifunctional Non-Coding RNAs Mediate Latent Infection and Recurrence of Herpes Simplex Viruses. Infect Drug Resist 2021; 14:5335-5349. [PMID: 34934329 PMCID: PMC8684386 DOI: 10.2147/idr.s334769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/30/2021] [Indexed: 12/14/2022] Open
Abstract
Herpes simplex viruses (HSVs) often cause latent infection for a lifetime, leading to repeated recurrence. HSVs have been engineered as oncolytic HSVs. The mechanism of the latent infection and recurrence remains largely unknown, which brings great challenges and limitations to eliminate HSVs in clinic and engineer safe oHSVs. Here, we systematically reviewed the latest development of the multi-step complex process of HSV latency and reactivation. Significantly, we first summarized the three HSV latent infection pathways, analyzed the structure and expression of the LAT1 and LAT2 of HSV-1 and HSV-2, proposed the regulation of LAT expression by four pathways, and dissected the function of LAT mediated by five LAT products of miRNAs, sRNAs, lncRNAs, sncRNAs and ORFs. We further analyzed that application of HSV LAT deletion mutants in HSV vaccines and oHSVs. Our review showed that deleting LAT significantly reduced the latency and reactivation of HSV, providing new ideas for the future development of safe and effective HSV therapeutics, vaccines and oHSVs. In addition, we proposed that RNA silencing or RNA interference may play an important role in HSV latency and reactivation, which is worth validating in future.
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Affiliation(s)
- Ying Zhang
- Department of Gastroenterology, Chun’an County First People’s Hospital (Zhejiang Provincial People’s Hospital Chun’an Branch), Hangzhou, Zhejiang Province, 311700, People’s Republic of China
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Molecular Biology and Biochemistry, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
| | - Li-Si Zeng
- State Key Laboratory of Respiratory Disease, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, People’s Republic of China
| | - Juan Wang
- Department of Obstetrics and Gynecology, Lianjiang People’s Hospital, Guangdong, 524400, People’s Republic of China
| | - Wen-Qi Cai
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Molecular Biology and Biochemistry, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
| | - Weiwen Cui
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Tong-Jun Song
- Department of Neurosurgery, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, Guangdong Province, 518104, People’s Republic of China
| | - Xiao-Chun Peng
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Pathophysiology, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
| | - Zhaowu Ma
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Molecular Biology and Biochemistry, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
| | - Ying Xiang
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Molecular Biology and Biochemistry, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
| | - Shu-Zhong Cui
- State Key Laboratory of Respiratory Disease, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, People’s Republic of China
| | - Hong-Wu Xin
- Laboratory of Oncology, Center for Molecular Medicine, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
- Department of Molecular Biology and Biochemistry, School of Basic Medicine, Health Science Center, Yangtze University, Jingzhou, Hubei, 434023, People’s Republic of China
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6
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Huang X, Li X, Yang L, Wang P, Yan J, Nie Z, Gao Y, Li Z, Wen J, Cao X. Construction and optimization of herpes simplex virus vectors for central nervous system gene delivery based on CRISPR/Cas9-mediated genome editing. Curr Gene Ther 2021; 22:66-77. [PMID: 34148538 DOI: 10.2174/1566523219666210618154326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/13/2021] [Accepted: 04/18/2021] [Indexed: 11/22/2022]
Abstract
AIMS We aim to define parameters affecting the safety and long-term transgene expression of attenuated HSV-1 vectors and optimize the expression cassettes to achieve robust and sustained expression in CNS. BACKGROUND Engineered, attenuated Herpes simplex virus (HSV) vectors are promising vehicles for gene delivery to the peripheral and central nervous systems. The virus latent promoter (LAP) is commonly used to drive exogenous gene expression; however, parameters affecting the safety and long-term transgene expression of attenuated HSV-1 vectors have not been fully understood. OBJECTIVE This study aimed to construct attenuated HSV-1 vectors using the CRISPR-Cas9 system and examine the influence of transgene cassette construction and insertion site on transgene expression and vector safety. METHOD In this study, we used a CRISPR-Cas9 system to accurately and efficiently edit attenuated HSV-1 strain 1716, and constructed two series of recombinant virus LMR and LMRx with different sets of gene cassettes insertion in Exon1(LAP2) and 2.0 kb intron downstream of LAP, respectively. The transgene expression and viral gene transcriptional kinetics were compared in in-vitro cell lines. The reporter gene expression and safety profiles of each vector were further evaluated in the mouse hippocampus gene transduction model. RESULT The in-vitro cell line analysis indicated that the insertion of a gene expression cassette would disrupt virus gene transcription. Mouse hippocampus transducing analysis suggested that complete expression cassette insertion at 2.0 kb intron could achieve robust and longtime gene expression than the other constructs. Recombinants with gene expression cassettes lacked Poly (A), which induced significant neuronal inflammation due to persistent viral antigen expression and microglia activation. CONCLUSION Our results indicated that the integrity of LAT transcripts was not necessary for the establishment of long-term latent expression. Exogenous strong promoters (like cBh promoter) could remain active during latency when placed in Exon1 or 2.0 Kb Intron of LAT locus, although their transcriptional activity declined with time. Consistent with previous research, the foreign gene expression would last much longer when the gene cassette was located downstream of Exon1, which suggested a role of LAP2 in maintaining promoter activity during latency. Besides, over-transcription of the downstream part of LAT may induce continuous activation of the attenuated vectors, suggesting an important role of LAT in maintaining viral reactivation potential.
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Affiliation(s)
- Xinwei Huang
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Xiuqing Li
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Lijuan Yang
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Pengfei Wang
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Jingyuan Yan
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Zuqing Nie
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Yingzheng Gao
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Zhiwei Li
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Jie Wen
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
| | - Xia Cao
- Key Laboratory of The Second Affiliated Hospital of Kuming Medical College, Kunming, 650101, China
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7
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Duarte LF, Reyes A, Farías MA, Riedel CA, Bueno SM, Kalergis AM, González PA. Crosstalk Between Epithelial Cells, Neurons and Immune Mediators in HSV-1 Skin Infection. Front Immunol 2021; 12:662234. [PMID: 34012447 PMCID: PMC8126613 DOI: 10.3389/fimmu.2021.662234] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/06/2021] [Indexed: 12/12/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) infection is highly prevalent in humans, with approximately two-thirds of the world population living with this virus. However, only a fraction of those carrying HSV-1, which elicits lifelong infections, are symptomatic. HSV-1 mainly causes lesions in the skin and mucosae but reaches the termini of sensory neurons innervating these tissues and travels in a retrograde manner to the neuron cell body where it establishes persistent infection and remains in a latent state until reactivated by different stimuli. When productive reactivations occur, the virus travels back along axons to the primary infection site, where new rounds of replication are initiated in the skin, in recurrent or secondary infections. During this process, new neuron infections occur. Noteworthy, the mechanisms underlying viral reactivations and the exit of latency are somewhat poorly understood and may be regulated by a crosstalk between the infected neurons and components of the immune system. Here, we review and discuss the immune responses that occur at the skin during primary and recurrent infections by HSV-1, as well as at the interphase of latently-infected neurons. Moreover, we discuss the implications of neuronal signals over the priming and migration of immune cells in the context of HSV-1 infection.
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Affiliation(s)
- Luisa F Duarte
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Antonia Reyes
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mónica A Farías
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia A Riedel
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo A González
- Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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8
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Herpes Simplex Virus 1 MicroRNA miR-H8 Is Dispensable for Latency and Reactivation In Vivo. J Virol 2021; 95:JVI.02179-20. [PMID: 33208453 DOI: 10.1128/jvi.02179-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/22/2022] Open
Abstract
The regulatory functions of 10 individual viral microRNAs (miRNAs) that are abundantly expressed from the herpes simplex virus 1 (HSV-1) latency-associated transcript (LAT) region remain largely unknown. Here, we focus on HSV-1 miRNA miR-H8, which is within the LAT 3p exon, antisense to the first intron of ICP0, and has previously been shown to target a host glycosylphosphatidylinositol (GPI)-anchoring pathway. However, the functions of this miRNA have not been assessed in the context of the viral genome during infection. Therefore, we constructed a recombinant virus lacking miR-H8 (17dmiR-H8) and compared it to the parental wild-type and rescue viruses to characterize phenotypic differences. In rabbit skin cells, 17dmiR-H8 exhibited only subtle reductions in viral yields. In contrast, we found significant decreases in both viral yields (8-fold) and DNA replication (9.9-fold) in murine neuroblastoma cells, while 17dmiR-H8 exhibited a 3.6-fold increase in DNA replication in differentiated human neuronal cells (Lund human mesencephalic [LUHMES] cells). These cell culture phenotypes suggested potential host- and/or neuron-specific roles for miR-H8 in acute viral replication. To assess whether miR-H8 plays a role in HSV latency or reactivation, we used a human in vitro reactivation model as well as mouse and rabbit reactivation models. In the LUHMES cell-induced reactivation model, there was no difference in viral yields at 48 h postreactivation. In the murine dorsal root ganglion explant and rabbit ocular adrenergic reactivation models, the deletion of miR-H8 had no detectable effect on genome loads during latency or reactivation. These results indicate that miR-H8 is dispensable for the establishment of HSV-1 latency and reactivation.IMPORTANCE Herpesviruses have a remarkable ability to sustain lifelong infections by evading host immune responses, establishing a latent reservoir, and maintaining the ability to reactivate the lytic cascade to transmit the virus to the next host. The HSV-1 latency-associated transcript region is known to regulate many aspects of HSV-1 latency and reactivation, although the mechanisms for these functions remain unknown. To this end, we characterize an HSV-1 recombinant containing a deletion of a LAT-encoded miRNA, miR-H8, and demonstrate that it plays no detectable role in the establishment of latency or reactivation in differentiated human neurons (LUHMES cells) and mouse and rabbit models. Therefore, this study allows us to exclude miR-H8 from phenotypes previously attributed to the LAT region. Elucidating the genetic elements of HSV-1 responsible for establishment, maintenance, and reactivation from latency may lead to novel strategies for combating persistent herpesvirus infections.
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9
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Herpes simplex virus 1 targets IRF7 via ICP0 to limit type I IFN induction. Sci Rep 2020; 10:22216. [PMID: 33335135 PMCID: PMC7747705 DOI: 10.1038/s41598-020-77725-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
Herpes 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.
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10
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Barrozo ER, Nakayama S, Singh P, Vanni EAH, Arvin AM, Neumann DM, Bloom DC. Deletion of Herpes Simplex Virus 1 MicroRNAs miR-H1 and miR-H6 Impairs Reactivation. J Virol 2020; 94:e00639-20. [PMID: 32295910 PMCID: PMC7375377 DOI: 10.1128/jvi.00639-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 12/13/2022] Open
Abstract
During all stages of infection, herpes simplex virus 1 (HSV-1) expresses viral microRNAs (miRNAs). There are at least 20 confirmed HSV-1 miRNAs, yet the roles of individual miRNAs in the context of viral infection remain largely uncharacterized. We constructed a recombinant virus lacking the sequences for miR-H1-5p and miR-H6-3p (17dmiR-H1/H6). The seed sequences for these miRNAs are antisense to each other and are transcribed from divergent noncoding RNAs in the latency-associated transcript (LAT) promoter region. Comparing phenotypes exhibited by the recombinant virus lacking these miRNAs to the wild type (17syn+), we found that during acute infection in cell culture, 17dmiR-H1/H6 exhibited a modest increase in viral yields. Analysis of pathogenesis in the mouse following footpad infection revealed a slight increase in virulence for 17dmiR-H1/H6 but no significant difference in the establishment or maintenance of latency. Strikingly, explant of latently infected dorsal root ganglia revealed a decreased and delayed reactivation phenotype. Further, 17dmiR-H1/H6 was severely impaired in epinephrine-induced reactivation in the rabbit ocular model. Finally, we demonstrated that deletion of miR-H1/H6 increased the accumulation of the LAT as well as several of the LAT region miRNAs. These results suggest that miR-H1/H6 plays an important role in facilitating efficient reactivation from latency.IMPORTANCE While HSV antivirals reduce the severity and duration of clinical disease in some individuals, there is no vaccine or cure. Therefore, understanding the mechanisms regulating latency and reactivation as a potential to elucidate targets for better therapeutics is important. There are at least 20 confirmed HSV-1 miRNAs, yet the roles of individual miRNAs in the context of viral infection remain largely uncharacterized. The present study focuses on two of the miRNAs (miR-H1/H6) that are encoded within the latency-associated transcript (LAT) region, a portion of the genome that has been associated with efficient reactivation. Here, we demonstrate that the deletion of the seed sequences of these miRNAs results in a severe reduction in reactivation of HSV-1 in the mouse and rabbit models. These results suggest a linkage between these miRNAs and reactivation.
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Affiliation(s)
- Enrico R Barrozo
- Department of Molecular Genetics & Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
- UF Genetics Institute, University of Florida, Gainesville, Florida, USA
| | - Sanae Nakayama
- Department of Molecular Genetics & Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Pankaj Singh
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Emilia A H Vanni
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Ann M Arvin
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Donna M Neumann
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David C Bloom
- Department of Molecular Genetics & Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
- UF Genetics Institute, University of Florida, Gainesville, Florida, USA
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11
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Disturbed Yin-Yang balance: stress increases the susceptibility to primary and recurrent infections of herpes simplex virus type 1. Acta Pharm Sin B 2020; 10:383-398. [PMID: 32140387 PMCID: PMC7049575 DOI: 10.1016/j.apsb.2019.06.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/27/2019] [Accepted: 05/31/2019] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic herpes virus, is able to establish a lifelong latent infection in the human host. Following primary replication in mucosal epithelial cells, the virus can enter sensory neurons innervating peripheral tissues via nerve termini. The viral genome is then transported to the nucleus where it can be maintained without producing infectious progeny, and thus latency is established in the cell. Yin–Yang balance is an essential concept in traditional Chinese medicine (TCM) theory. Yin represents stable and inhibitory factors, and Yang represents the active and aggressive factors. When the organism is exposed to stress, especially psychological stress caused by emotional stimulation, the Yin–Yang balance is disturbed and the virus can re-engage in productive replication, resulting in recurrent diseases. Therefore, a better understanding of the stress-induced susceptibility to HSV-1 primary infection and reactivation is needed and will provide helpful insights into the effective control and treatment of HSV-1. Here we reviewed the recent advances in the studies of HSV-1 susceptibility, latency and reactivation. We included mechanisms involved in primary infection and the regulation of latency and described how stress-induced changes increase the susceptibility to primary and recurrent infections.
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Key Words
- 4E-BP, eIF4E-binding protein
- AD, Alzheimer's disease
- AKT, protein kinase B
- AMPK, AMP-dependent kinase
- BCL-2, B-cell lymphoma 2
- CNS, central nervous system
- CORT, corticosterone
- CPE, cytopathic effect
- CTCF, CCCTC-binding factor
- CTL, cytotoxic T lymphocyte
- CoREST, REST corepressor 1
- DAMPs, damage-associated molecular patterns
- DCs, dendritic cells
- DEX, dexamethasone
- GREs, GR response elements
- GRs, glucocorticoid receptors
- H3K9, histone H3 on lysines 9
- HCF-1, host cell factor 1
- HDACs, histone deacetylases
- HPA axis, hypothalamo–pituitary–adrenal axis
- HPK, herpetic simplex keratitis
- HPT axis, hypothalamic–pituitary–thyroid axis
- HSV-1
- HSV-1, herpes simplex virus type 1
- Herpes simplex virus type 1
- ICP, infected cell polypeptide
- IRF3, interferon regulatory factor 3
- KLF15, Krüppel-like transcription factor 15
- LAT, latency-associated transcripts
- LRF, Luman/CREB3 recruitment factor
- LSD1, lysine-specific demethylase 1
- Latency
- MAVS, mitochondrial antiviral-signaling protein
- MOI, multiplicity of infection
- ND10, nuclear domains 10
- NGF, nerve growth factor
- NK cells, natural killer cells
- OCT-1, octamer binding protein 1
- ORFs, open reading frames
- PAMPs, pathogen-associated molecular patterns
- PDK1, pyruvate dehydrogenase lipoamide kinase isozyme 1
- PI3K, phosphoinositide 3-kinases
- PML, promyelocytic leukemia protein
- PNS, peripheral nervous system
- PRC1, protein regulator of cytokinesis 1
- PRRs, pattern-recognition receptors
- PTMs, post-translational modifications
- RANKL, receptor activator of NF-κB ligands
- REST, RE1-silencing transcription factor
- ROS, reactive oxygen species
- Reactivation
- SGKs, serum and glucocorticoid-regulated protein kinases
- SIRT1, sirtuin 1
- Stress
- Susceptibility
- T3, thyroid hormone
- TCM, traditional Chinese medicine
- TG, trigeminal ganglia
- TK, thymidine kinase
- TRIM14, tripartite motif-containing 14
- TRKA, tropomyosin receptor kinase A
- TRM, tissue resident memory T cells
- cGAS, cyclic GMP-AMP synthase
- mTOR, mammalian target of rapamycin
- sncRNAs, small non-coding RNAs
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12
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Naqvi AR. Immunomodulatory roles of human herpesvirus-encoded microRNA in host-virus interaction. Rev Med Virol 2020; 30:e2081. [PMID: 31432608 PMCID: PMC7398577 DOI: 10.1002/rmv.2081] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022]
Abstract
Human herpesviruses (HHV) are large, double stranded, DNA viruses with high seroprevalence across the globe. Clinical manifestation of primary HHV infection resolve shortly, however, this period is prolonged in immunocompromised patients or individuals with suppressed immunity. Examining molecular mechanisms of HHV-encoded virulence factors can provide finer details of HHV-host interaction. A unique genetic feature of most members of HHV is that they encode multiple microRNAs (miR). In this review, I will provide mechanistic insights into the immunomodulatory functions of herpesvirus-encoded viral miR (v-miR) that favor viral persistence and spread by ingenious immune evasion schemes. Similar to host miR, v-miR can simultaneously regulate expression of multiple transcripts including host- and virus-derived. V-miRs, by virtue of their direct interaction with various transcripts, can regulate expression of critical components of host innate and adaptive immune system. V-miRs are also exported through exosomal route and gain entry into various cells even at distant sites, thereby allowing HHV to manipulate cellular and tissue immunity. Targeting v-miR may serve as a novel and promising therapeutic candidate to mitigate HHV-mediated clinical manifestations.
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Affiliation(s)
- Afsar R Naqvi
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, USA
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13
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Xu S, Hazlett LD. MicroRNAs in Ocular Infection. Microorganisms 2019; 7:microorganisms7090359. [PMID: 31533211 PMCID: PMC6780979 DOI: 10.3390/microorganisms7090359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022] Open
Abstract
MicroRNAs (miRNAs) are small, non-coding, regulatory RNA molecules and constitute a newly recognized, important layer of gene-expression regulation at post-transcriptional levels. miRNAs quantitatively fine tune the expression of their downstream genes in a cell type- and developmental stage-specific fashion. miRNAs have been proven to play important roles in the normal development and function as well as in the pathogenesis of diseases in all tissues and organ systems. miRNAs have emerged as new therapeutic targets and biomarkers for treatment and diagnosis of various diseases. Although miRNA research in ocular infection remains in its early stages, a handful of pioneering studies have provided insight into the roles of miRNAs in the pathogenesis of parasitic, fungal, bacterial, and viral ocular infections. Here, we review the current status of research in miRNAs in several major ocular infectious diseases. We predict that the field of miRNAs in ocular infection will greatly expand with the discovery of novel miRNA-involved molecular mechanisms that will inform development of new therapies and identify novel diagnostic biomarkers.
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Affiliation(s)
- Shunbin Xu
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, School of Medicine, Detroit, MI 48201, USA.
| | - Linda D Hazlett
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, School of Medicine, Detroit, MI 48201, USA.
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14
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Herpes Simplex Virus Type 1-Encoded miR-H2-3p Manipulates Cytosolic DNA-Stimulated Antiviral Innate Immune Response by Targeting DDX41. Viruses 2019; 11:v11080756. [PMID: 31443275 PMCID: PMC6723821 DOI: 10.3390/v11080756] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/28/2019] [Accepted: 08/06/2019] [Indexed: 12/17/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1), one of the human pathogens widely epidemic and transmitted among various groups of people in the world, often causes symptoms known as oral herpes or lifelong asymptomatic infection. HSV-1 employs many sophisticated strategies to escape host antiviral immune response based on its multiple coding proteins. However, the functions involved in the immune evasion of miRNAs encoded by HSV-1 during lytic (productive) infection remain poorly studied. Dual-luciferase reporter gene assay and bioinformatics revealed that Asp-Glu-Ala-Asp (DEAD)-box helicase 41 (DDX41), a cytosolic DNA sensor of the DNA-sensing pathway, was a putative direct target gene of HSV-1-encoded miR-H2-3p. The transfection of miR-H2-3p mimics inhibited the expression of DDX41 at the level of mRNA and protein, as well as the expression of interferon beta (IFN-β) and myxoma resistance protein I (MxI) induced by HSV-1 infection in THP-1 cells, and promoted the viral replication and its gene transcription. However, the transfection of miR-H2-3p inhibitor showed opposite effects. This finding indicated that HSV-1-encoded miR-H2-3p attenuated cytosolic DNA-stimulated antiviral immune response by manipulating host DNA sensor molecular DDX41 to enhance virus replication in cultured cells.
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15
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Effect of Loss-of-function of the Herpes Simplex Virus-1 microRNA H6-5p on Virus Replication. Virol Sin 2019; 34:386-396. [PMID: 31020575 DOI: 10.1007/s12250-019-00111-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/28/2019] [Indexed: 12/31/2022] Open
Abstract
To date, 29 distinct microRNAs (miRNAs) have been reported to be expressed during herpes simplex virus infections. Sequence analysis of mature herpes simplex virus-1 (HSV-1) miRNAs revealed five sets of miRNAs that are complementary to each other: miR-H6-5p/H1-3p, miR-H6-3p/H1-5p, H2-5p/H14-3p, miR-H2-3p/H14-5p, and miR-H7/H27. However, the roles of individual miRNAs and consequences of this complementarity remain unclear. Here, we focus on two of these complementary miRNAs, miR-H6-5p and miR-H1-3p, using loss-of-function experiments in vitro and in a mouse model of infection using an miRNA sponge approach, including tandem multiplex artificial miRNA-binding sequences that do not match perfectly to the target miRNA inserted downstream of a green fluorescent protein reporter gene. Infection with recombinant virus expressing the miR-H6-5p sponge reduced viral protein levels and virus yield. Decreased accumulation of viral proteins was also observed at early stages of infection in the presence of both an miR-H6-5p inhibitor and plasmid-expressed miR-H1-3p. Moreover, establishment of latency and reactivation did not differ between the recombinant virus expressing the miR-H6-5p sponge and wild-type HSV-1. Taken together, these data suggest that miR-H6-5p has an as-yet-unidentified role in the early stages of viral infection, and its complement miR-H1-3p suppresses this role in later stages of infection. This report extends understanding of the roles of miRNAs in infection by herpes simplex viruses, supporting a model of infection in which the production of virus and its virulent effects are tightly controlled to maximize persistence in the host and population.
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16
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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 + T EM Cells Are Associated with Asymptomatic Herpes in Humans. J Virol 2019; 93:JVI.01882-18. [PMID: 30487281 DOI: 10.1128/jvi.01882-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 11/22/2018] [Indexed: 01/23/2023] Open
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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17
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Cokarić Brdovčak M, Zubković A, Jurak I. Herpes Simplex Virus 1 Deregulation of Host MicroRNAs. Noncoding RNA 2018; 4:ncrna4040036. [PMID: 30477082 PMCID: PMC6316616 DOI: 10.3390/ncrna4040036] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/15/2018] [Accepted: 11/19/2018] [Indexed: 02/06/2023] Open
Abstract
Viruses utilize microRNAs (miRNAs) in a vast variety of possible interactions and mechanisms, apparently far beyond the classical understanding of gene repression in humans. Likewise, herpes simplex virus 1 (HSV-1) expresses numerous miRNAs and deregulates the expression of host miRNAs. Several HSV-1 miRNAs are abundantly expressed in latency, some of which are encoded antisense to transcripts of important productive infection genes, indicating their roles in repressing the productive cycle and/or in maintenance/reactivation from latency. In addition, HSV-1 also exploits host miRNAs to advance its replication or repress its genes to facilitate latency. Here, we discuss what is known about the functional interplay between HSV-1 and the host miRNA machinery, potential targets, and the molecular mechanisms leading to an efficient virus replication and spread.
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Affiliation(s)
- Maja Cokarić Brdovčak
- Laboratory for Molecular Virology, Department of Biotechnology, University of Rijeka, R. Matejčić 2, HR-51000 Rijeka, Croatia.
| | - Andreja Zubković
- Laboratory for Molecular Virology, Department of Biotechnology, University of Rijeka, R. Matejčić 2, HR-51000 Rijeka, Croatia.
| | - Igor Jurak
- Laboratory for Molecular Virology, Department of Biotechnology, University of Rijeka, R. Matejčić 2, HR-51000 Rijeka, Croatia.
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18
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Herpes Simplex Virus 2 Latency-Associated Transcript (LAT) Region Mutations Do Not Identify a Role for LAT-Associated MicroRNAs in Viral Reactivation in Guinea Pig Genital Models. J Virol 2018; 92:JVI.00642-18. [PMID: 29720520 DOI: 10.1128/jvi.00642-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 04/16/2018] [Indexed: 02/08/2023] Open
Abstract
Despite the long-standing observation that herpes simplex virus (HSV) latency-associated transcript (LAT) promoter deletion viruses show impaired recurrence phenotypes in relevant animal models, the mechanism by which these sequences exert this phenotypic effect is unknown. We constructed and evaluated four mutant HSV-2 isolates with targeted mutations in the LAT promoter and LAT-associated microRNAs (miRNAs) affecting (i) the LAT TATA box; (ii) the LAT ICP4-binding site; (iii) miRNA I (miR-I) and miR-II (miR-I/II), which both target ICP34.5; and (iv) miR-III, which targets ICP0. While the LAT TATA box mutant caused milder acute infections than wild-type (WT) virus, there was no difference in the recurrence phenotype between these viruses. LAT and miRNA expression during latency was not impaired by this mutation, suggesting that other promoter elements may be more important for latent HSV-2 LAT expression. Mutation of the LAT ICP4-binding site also did not cause an in vivo phenotypic difference between mutant and WT viruses. Acute infection and reactivation from latency of the miR-I/II mutant were similar to those of its rescuant, although the acute infection was slightly reduced in severity relative to that caused by the wild-type virus. The miR-III mutant also exhibited WT phenotypes in acute and recurrent phases of infection. While they do not rule out an effect of these elements in human latency or reactivation, these findings do not identify a specific role for LAT or LAT-associated miRNAs in the HSV-2 LAT promoter deletion phenotype in guinea pigs. Thus, other sequences in this region may play a more important role in the long-studied LAT-associated phenotype in animals.IMPORTANCE While it has been known for several decades that specific HSV-1 and HSV-2 sequences near the LAT promoter are required for efficient viral reactivation in animal models, the mechanism is still not known. We constructed four mutant viruses with the goal of identifying critical sequence elements and of specifically testing the hypothesis that microRNAs that are expressed during latency play a role. Determination that specific LAT promoter sequences and miRNA sequences do not influence viral reactivation of HSV-2 helps to narrow down the search for the mechanism by which the virus controls its latency and recurrence phenotype.
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19
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Phelan D, Barrozo ER, Bloom DC. HSV1 latent transcription and non-coding RNA: A critical retrospective. J Neuroimmunol 2017; 308:65-101. [PMID: 28363461 DOI: 10.1016/j.jneuroim.2017.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 12/22/2022]
Abstract
Virologists have invested great effort into understanding how the herpes simplex viruses and their relatives are maintained dormant over the lifespan of their host while maintaining the poise to remobilize on sporadic occasions. Piece by piece, our field has defined the tissues in play (the sensory ganglia), the transcriptional units (the latency-associated transcripts), and the responsive genomic region (the long repeats of the viral genomes). With time, the observed complexity of these features has compounded, and the totality of viral factors regulating latency are less obvious. In this review, we compose a comprehensive picture of the viral genetic elements suspected to be relevant to herpes simplex virus 1 (HSV1) latent transcription by conducting a critical analysis of about three decades of research. We describe these studies, which largely involved mutational analysis of the notable latency-associated transcripts (LATs), and more recently a series of viral miRNAs. We also intend to draw attention to the many other less characterized non-coding RNAs, and perhaps coding RNAs, that may be important for consideration when trying to disentangle the multitude of phenotypes of the many genetic modifications introduced into recombinant HSV1 strains.
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Affiliation(s)
- Dane Phelan
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
| | - Enrico R Barrozo
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
| | - David C Bloom
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
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Mutations Inactivating Herpes Simplex Virus 1 MicroRNA miR-H2 Do Not Detectably Increase ICP0 Gene Expression in Infected Cultured Cells or Mouse Trigeminal Ganglia. J Virol 2017; 91:JVI.02001-16. [PMID: 27847363 DOI: 10.1128/jvi.02001-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/07/2016] [Indexed: 12/23/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) latency entails the repression of productive ("lytic") gene expression. An attractive hypothesis to explain some of this repression involves inhibition of the expression of ICP0, a lytic gene activator, by a viral microRNA, miR-H2, which is completely complementary to ICP0 mRNA. To test this hypothesis, we engineered mutations that disrupt miR-H2 without affecting ICP0 in HSV-1. The mutant virus exhibited drastically reduced expression of miR-H2 but showed wild-type levels of infectious virus production and no increase in ICP0 expression in lytically infected cells, which is consistent with the weak expression of miR-H2 relative to the level of ICP0 mRNA in that setting. Following corneal inoculation of mice, the mutant was not significantly different from wild-type virus in terms of infectious virus production in the trigeminal ganglia during acute infection, mouse mortality, or the rate of reactivation from explanted latently infected ganglia. Critically, the mutant was indistinguishable from wild-type virus for the expression of ICP0 and other lytic genes in acutely and latently infected mouse trigeminal ganglia. The latter result may be related to miR-H2 being less effective in inhibiting ICP0 expression in transfection assays than a host microRNA, miR-138, which has previously been shown to inhibit lytic gene expression in infected ganglia by targeting ICP0 mRNA. Additionally, transfected miR-138 reduced lytic gene expression in infected cells more effectively than miR-H2. While this study provides little support for the hypothesis that miR-H2 promotes latency by inhibiting ICP0 expression, the possibility remains that miR-H2 might target other genes during latency. IMPORTANCE Herpes simplex virus 1 (HSV-1), which causes a variety of diseases, can establish lifelong latent infections from which virus can reactivate to cause recurrent disease. Latency is the most biologically interesting and clinically vexing feature of the virus. Ever since miR-H2's discovery as a viral microRNA bearing complete sequence complementarity to the mRNA for the important viral gene activator ICP0, inhibition of ICP0 expression by miR-H2 has been a major hypothesis to help explain the repression of lytic gene expression during latency. However, this hypothesis remained untested in latently infected animals. Using a miR-H2-deficient mutant virus, we found no evidence that miR-H2 represses the expression of ICP0 or other lytic genes in cells or mice infected with HSV-1. Although miR-H2 can repress ICP0 expression in transfection assays, such repression is weak. The results suggest that other mechanisms for miR-H2 activity and for the repression of lytic gene expression during latency deserve investigation.
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21
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The small noncoding RNAs (sncRNAs) of murine gammaherpesvirus 68 (MHV-68) are involved in regulating the latent-to-lytic switch in vivo. Sci Rep 2016; 6:32128. [PMID: 27561205 PMCID: PMC4999806 DOI: 10.1038/srep32128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/02/2016] [Indexed: 01/05/2023] Open
Abstract
The human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV), which are associated with a variety of diseases including tumors, produce various small noncoding RNAs (sncRNAs) such as microRNAs (miRNAs). Like all herpesviruses, they show two stages in their life cycle: lytic replication and latency. During latency, hardly any viral proteins are expressed to avoid recognition by the immune system. Thus, sncRNAs might be exploited since they are less likely to be recognized. Specifically, it has been proposed that sncRNAs might contribute to the maintenance of latency. This has already been shown in vitro, but the respective evidence in vivo is very limited. A natural model system to explore this question in vivo is infection of mice with murine gammaherpesvirus 68 (MHV-68). We used this model to analyze a MHV-68 mutant lacking the expression of all miRNAs. In the absence of the miRNAs, we observed a higher viral genomic load during late latency in the spleens of mice. We propose that this is due to a disturbed regulation of the latent-to-lytic switch, altering the balance between latent and lytic infection. Hence, we provide for the first time evidence that gammaherpesvirus sncRNAs contribute to the maintenance of latency in vivo.
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22
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Szczubiałka K, Pyrć K, Nowakowska M. In search for effective and definitive treatment of herpes simplex virus type 1 (HSV-1) infections. RSC Adv 2016. [DOI: 10.1039/c5ra22896d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Herpes Simplex Virus type 1 (HSV-1) is a nuclear replicating enveloped virus.
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Affiliation(s)
| | - Krzysztof Pyrć
- Faculty of Biochemistry, Biophysics and Biotechnology
- Jagiellonian University
- 30-387 Kraków
- Poland
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