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Dochnal SA, Krakowiak PA, Whitford AL, Cliffe AR. Physiological oxygen concentration during sympathetic primary neuron culture improves neuronal health and reduces HSV-1 reactivation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.09.607366. [PMID: 39149301 PMCID: PMC11326244 DOI: 10.1101/2024.08.09.607366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Herpes simplex virus-1 (HSV-1) establishes a latent infection in peripheral neurons and periodically reactivates in response to a stimulus to permit transmission. In vitro models using primary neurons are invaluable to studying latent infection because they use bona fide neurons that have undergone differentiation and maturation in vivo. However, culture conditions in vitro should remain as close to those in vivo as possible. This is especially important when considering minimizing cell stress, as it is a well-known trigger of HSV reactivation. We recently developed an HSV-1 model system that requires neurons to be cultured for extended lengths of time. Therefore, we sought to refine culture conditions to optimize neuronal health and minimize secondary effects on latency and reactivation. Here, we demonstrate that culturing primary neurons under conditions closer to physiological oxygen concentrations (5% oxygen) results in cultures with features consistent with reduced stress. Furthermore, culture in these lower oxygen conditions diminishes the progression to full HSV-1 reactivation despite minimal impacts on latency establishment and earlier stages of HSV-1 reactivation. We anticipate that our findings will be useful for the broader microbiology community as they highlight the importance of considering physiological oxygen concentration in studying host-pathogen interactions.
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Affiliation(s)
- Sara A Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
- Present address: Department of Anesthesiology, University of California, San Diego, La Jolla, CA, 92037
| | - Patryk A Krakowiak
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Abigail L Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Anna R Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
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Cuddy SR, Flores ME, Krakowiak PA, Whitford AL, Dochnal SA, Babnis A, Miyake T, Tigano M, Engel DA, Cliffe AR. Co-option of mitochondrial nucleic acid sensing pathways by HSV-1 UL12.5 for reactivation from latent Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.06.601241. [PMID: 39005440 PMCID: PMC11245091 DOI: 10.1101/2024.07.06.601241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Although viruses subvert innate immune pathways for their replication, there is evidence they can also co-opt anti-viral responses for their benefit. The ubiquitous human pathogen, Herpes Simplex Virus-1 (HSV-1), encodes a protein (UL12.5) that induces the release of mitochondrial nucleic acid into the cytosol, which activates immune sensing pathways and reduces productive replication in non-neuronal cells. HSV-1 establishes latency in neurons and can reactivate to cause disease. We found that UL12.5 is required for HSV-1 reactivation in neurons and acts to directly promote viral lytic gene expression during initial exit from latency. Further, the direct activation of innate immune sensing pathways triggered HSV reactivation and compensated for a lack of UL12.5. Finally, we found that the induction of HSV-1 lytic genes during reactivation required intact RNA and DNA sensing pathways, demonstrating that HSV-1 can both respond to and active antiviral nucleic acid sensing pathways to reactivate from a latent infection.
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Affiliation(s)
- Sean R. Cuddy
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, 22908
| | - Matthew E. Flores
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Patryk A. Krakowiak
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Abigail L. Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Sara A. Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Aleksandra Babnis
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Tsuyoshi Miyake
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Marco Tigano
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, 1020 Locust Street, Philadelphia 19107
| | - Daniel A. Engel
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Anna. R Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
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Domanico LF, Dunn GP, Kobiler O, Taylor MP. A dual fluorescent herpes simplex virus type 1 recombinant reveals divergent outcomes of neuronal infection. J Virol 2024; 98:e0003224. [PMID: 38651900 PMCID: PMC11092338 DOI: 10.1128/jvi.00032-24] [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: 01/05/2024] [Accepted: 04/01/2024] [Indexed: 04/25/2024] Open
Abstract
Critical stages of lytic herpes simplex virus type 1 (HSV-1) replication are marked by the sequential expression of immediate early (IE) to early (E), then late (L) viral genes. HSV-1 can also persist in neuronal cells via a non-replicative, transcriptionally repressed infection called latency. The regulation of lytic and latent transcriptional profiles is critical to HSV-1 pathogenesis and persistence. We sought a fluorescence-based approach to observe the outcome of neuronal HSV-1 infection at the single-cell level. To achieve this goal, we constructed and characterized a novel HSV-1 recombinant that enables discrimination between lytic and latent infection. The dual reporter HSV-1 encodes a human cytomegalovirus-immediate early (hCMV-IE) promoter-driven enhanced yellow fluorescent protein (eYFP) to visualize the establishment of infection and an endogenous mCherry-VP26 fusion to report lytic replication. We confirmed that viral gene expression, replication, and spread of infection are not altered by the incorporation of the fluorescent reporters, and fluorescent protein (FP) detection virtuously reports the progression of lytic replication. We demonstrate that the outcome of HSV-1 infection of compartmentalized primary neurons is determined by viral inoculating dose: high-dose axonal inoculation proceeds to lytic replication, whereas low-dose axonal inoculation establishes a latent HSV-1 infection. Interfering with low-dose axonal inoculation via small molecule drugs reports divergent phenotypes of eYFP and mCherry reporter detection, correlating with altered states of viral gene expression. We report that the transcriptional state of neuronal HSV-1 infection is variable in response to changes in the intracellular neuronal environment.IMPORTANCEHerpes simplex virus type 1 (HSV-1) is a prevalent human pathogen that infects approximately 67% of the global human population. HSV-1 invades the peripheral nervous system, where latent HSV-1 infection persists within the host for life. Immunological evasion, viral persistence, and herpetic pathologies are determined by the regulation of HSV-1 gene expression. Studying HSV-1 gene expression during neuronal infection is challenging but essential for the development of antiviral therapeutics and interventions. We used a recombinant HSV-1 to evaluate viral gene expression during infection of primary neurons. Manipulation of cell signaling pathways impacts the establishment and transcriptional state of HSV-1 latency in neurons. The work here provides critical insight into the cellular and viral factors contributing to the establishment of latent HSV-1 infection.
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Affiliation(s)
- Luke F. Domanico
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Gary P. Dunn
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Oren Kobiler
- Department of Clinical Microbiology and Immunology, School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Matthew P. Taylor
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
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Dochnal SA, Whitford AL, Francois AK, Krakowiak PA, Cuddy S, Cliffe AR. c-Jun signaling during initial HSV-1 infection modulates latency to enhance later reactivation in addition to directly promoting the progression to full reactivation. J Virol 2024; 98:e0176423. [PMID: 38193709 PMCID: PMC10878265 DOI: 10.1128/jvi.01764-23] [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: 11/10/2023] [Accepted: 12/12/2023] [Indexed: 01/10/2024] Open
Abstract
Herpes simplex virus-1 (HSV-1) establishes a latent infection in peripheral neurons and periodically reactivates to permit transmission, which can result in clinical manifestations. Viral transactivators required for lytic infection are largely absent during latent infection, and therefore, HSV-1 relies on the co-option of neuronal host signaling pathways to initiate its gene expression. The activation of the neuronal c-Jun N-terminal kinase (JNK) cell stress pathway is central to initiating biphasic reactivation in response to multiple stimuli. However, how host factors work with JNK to stimulate the initial wave of gene expression (known as Phase I) or the progression to full Phase II reactivation remains unclear. Here, we found that c-Jun, the primary target downstream of neuronal JNK cell stress signaling, functions during reactivation but not during the JNK-mediated initiation of Phase I gene expression. Instead, c-Jun was required to transition from Phase I to full HSV-1 reactivation and was detected in viral replication compartments of reactivating neurons. Interestingly, we also identified a role for both c-Jun and enhanced neuronal stress during initial neuronal infection in promoting a more reactivation-competent form of HSV-1 latency. Therefore, c-Jun functions at multiple stages during the HSV latent infection of neurons to promote reactivation but not during the initial JNK-dependent Phase I. Importantly, by demonstrating that initial infection conditions can contribute to later reactivation abilities, this study highlights the potential for latently infected neurons to maintain a molecular scar of previous exposure to neuronal stressors.IMPORTANCEThe molecular mechanisms that regulate the reactivation of herpes simplex virus-1 (HSV-1) from latent infection are unknown. The host transcription and pioneer factor c-Jun is the main target of the JNK cell stress pathway that is known to be important in exit of HSV from latency. Surprisingly, we found that c-Jun does not act with JNK during exit from latency but instead promotes the transition to full reactivation. Moreover, c-Jun and enhanced neuronal stress during initial neuronal infection promoted a more reactivation-competent form of HSV-1 latency. c-Jun, therefore, functions at multiple stages during HSV-1 latent infection of neurons to promote reactivation. Importantly, this study contributes to a growing body of evidence that de novo HSV-1 infection conditions can modulate latent infection and impact future reactivation events, raising important questions on the clinical impact of stress during initial HSV-1 acquisition on future reactivation events and consequences.
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Affiliation(s)
- Sara A. Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Abigail L. Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Alison K. Francois
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Patryk A. Krakowiak
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Sean Cuddy
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA
| | - Anna R. Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
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Köster KA, Dethlefs M, Duque Escobar J, Oetjen E. Regulation of the Activity of the Dual Leucine Zipper Kinase by Distinct Mechanisms. Cells 2024; 13:333. [PMID: 38391946 PMCID: PMC10886912 DOI: 10.3390/cells13040333] [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: 12/29/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
The dual leucine zipper kinase (DLK) alias mitogen-activated protein 3 kinase 12 (MAP3K12) has gained much attention in recent years. DLK belongs to the mixed lineage kinases, characterized by homology to serine/threonine and tyrosine kinase, but exerts serine/threonine kinase activity. DLK has been implicated in many diseases, including several neurodegenerative diseases, glaucoma, and diabetes mellitus. As a MAP3K, it is generally assumed that DLK becomes phosphorylated and activated by upstream signals and phosphorylates and activates itself, the downstream serine/threonine MAP2K, and, ultimately, MAPK. In addition, other mechanisms such as protein-protein interactions, proteasomal degradation, dephosphorylation by various phosphatases, palmitoylation, and subcellular localization have been shown to be involved in the regulation of DLK activity or its fine-tuning. In the present review, the diverse mechanisms regulating DLK activity will be summarized to provide better insights into DLK action and, possibly, new targets to modulate DLK function.
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Affiliation(s)
- Kyra-Alexandra Köster
- Department of Clinical Pharmacology and Toxicology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany; (K.-A.K.); (M.D.)
- DZHK Standort Hamburg, Kiel, Lübeck, Germany;
| | - Marten Dethlefs
- Department of Clinical Pharmacology and Toxicology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany; (K.-A.K.); (M.D.)
- DZHK Standort Hamburg, Kiel, Lübeck, Germany;
| | - Jorge Duque Escobar
- DZHK Standort Hamburg, Kiel, Lübeck, Germany;
- University Center of Cardiovascular Science, Department of Cardiology, University Heart & Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Elke Oetjen
- Department of Clinical Pharmacology and Toxicology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany; (K.-A.K.); (M.D.)
- DZHK Standort Hamburg, Kiel, Lübeck, Germany;
- Institute of Pharmacy, University of Hamburg, 20146 Hamburg, Germany
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Zubković A, Gomes C, Parchure A, Cesarec M, Ferenčić A, Rokić F, Jakovac H, Whitford AL, Dochnal SA, Cliffe AR, Cuculić D, Gallo A, Vugrek O, Hackenberg M, Jurak I. HSV-1 miRNAs are post-transcriptionally edited in latently infected human ganglia. J Virol 2023; 97:e0073023. [PMID: 37712701 PMCID: PMC10617394 DOI: 10.1128/jvi.00730-23] [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: 05/25/2023] [Accepted: 07/10/2023] [Indexed: 09/16/2023] Open
Abstract
IMPORTANCE Herpes simplex virus 1 is an important human pathogen that has been intensively studied for many decades. Nevertheless, the molecular mechanisms regulating its establishment, maintenance, and reactivation from latency are poorly understood. Here, we show that HSV-1-encoded miR-H2 is post-transcriptionally edited in latently infected human tissues. Hyperediting of viral miRNAs increases the targeting potential of these miRNAs and may play an important role in regulating latency. We show that the edited miR-H2 can target ICP4, an essential viral protein. Interestingly, we found no evidence of hyperediting of its homolog, miR-H2, which is expressed by the closely related virus HSV-2. The discovery of post-translational modifications of viral miRNA in the latency phase suggests that these processes may also be important for other non-coding viral RNA in the latency phase, including the intron LAT, which in turn may be crucial for understanding the biology of this virus.
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Affiliation(s)
- Andreja Zubković
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Cristina Gomes
- Genetics Department and Biotechnology Institute, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Adwait Parchure
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Mia Cesarec
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Antun Ferenčić
- Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Filip Rokić
- Laboratory for Advanced Genomics, Institute Ruđer Bošković, Zagreb, Croatia
| | - Hrvoje Jakovac
- Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Abigail L. Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Sara A. Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Anna R. Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Dražen Cuculić
- Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Angela Gallo
- Department of Onco-Haematology and Cell and Gene Therapy, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Oliver Vugrek
- Laboratory for Advanced Genomics, Institute Ruđer Bošković, Zagreb, Croatia
| | - Michael Hackenberg
- Genetics Department and Biotechnology Institute, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Igor Jurak
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
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Cuddy SR, Cliffe AR. The Intersection of Innate Immune Pathways with the Latent Herpes Simplex Virus Genome. J Virol 2023; 97:e0135222. [PMID: 37129520 PMCID: PMC10231182 DOI: 10.1128/jvi.01352-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 04/07/2023] [Indexed: 05/03/2023] Open
Abstract
Innate immune responses can impact different stages of viral life cycles. Herpes simplex virus latent infection of neurons and subsequent reactivation provide a unique context for immune responses to intersect with different stages of infection. Here, we discuss recent findings linking neuronal innate immune pathways with the modulation of latent infection, acting at the time of reactivation and during initial neuronal infection to have a long-term impact on the ability of the virus to reactivate.
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Affiliation(s)
- Sean R. Cuddy
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA
| | - Anna R. Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
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Impact of Cultured Neuron Models on α-Herpesvirus Latency Research. Viruses 2022; 14:v14061209. [PMID: 35746680 PMCID: PMC9228292 DOI: 10.3390/v14061209] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 02/01/2023] Open
Abstract
A signature trait of neurotropic α-herpesviruses (α-HV) is their ability to establish stable non-productive infections of peripheral neurons termed latency. This specialized gene expression program is the foundation of an evolutionarily successful strategy to ensure lifelong persistence in the host. Various physiological stresses can induce reactivation in a subset of latently-infected neurons allowing a new cycle of viral productive cycle gene expression and synthesis of infectious virus. Recurring reactivation events ensure transmission of the virus to new hosts and contributes to pathogenesis. Efforts to define the molecular basis of α-HV latency and reactivation have been notoriously difficult because the neurons harboring latent virus in humans and in experimentally infected live-animal models, are rare and largely inaccessible to study. Increasingly, researchers are turning to cultured neuron infection models as simpler experimental platforms from which to explore latency and reactivation at the molecular level. In this review, I reflect on the strengths and weaknesses of existing neuronal models and briefly summarize the important mechanistic insights these models have provided. I also discuss areas where prioritization will help to ensure continued progress and integration.
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