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Inherited Chromosomally Integrated Human Herpesvirus 6: Laboratory and Clinical Features. Microorganisms 2023; 11:microorganisms11030548. [PMID: 36985122 PMCID: PMC10052293 DOI: 10.3390/microorganisms11030548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Inherited chromosomally integrated human herpesvirus 6 (iciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the chromosomes of the host germ cell and is vertically transmitted. The aims of this study were to identify iciHHV-6 prevalence in hospitalized patients and clinical features in individuals carrying this integration. HHV-6 PCR on hair follicles was used to confirm iciHHV-6 status when the blood viral load was more than 5 Log10 copies/mL. From January 2012 to June 2022, HHV-6 DNAemia was investigated in 2019 patients. In particular, 49 had a viral load higher than 6 Log10 copies/mL and HHV-6 DNA in hair follicles was positive. A viral load between 5.0 and 5.9 Log10 copies/mL was observed in 10 patients: 6 infants with acute HHV-6 infection and 4 patients with leukopenia and HHV-6 integration. Therefore, the iciHHV-6 prevalence in our population was 2.6% (53/2019). Adult patients with integration presented hematological (24%), autoimmune (11%), autoimmune neurological (19%), not-autoimmune neurological (22%), and other diseases (19%), whereas 5% had no clinically relevant disease. Although in our study population a high percentage of iciHHV-6 adult hospitalized patients presented a specific pathology, it is still unknown whether the integration is responsible for, or contributes to, the disease development.
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Hogestyn JM, Salois G, Xie L, Apa C, Youngyunpipatkul J, Pröschel C, Mayer-Pröschel M. Expression of the human herpesvirus 6A latency-associated transcript U94A impairs cytoskeletal functions in human neural cells. Mol Cell Neurosci 2022; 123:103770. [PMID: 36055520 PMCID: PMC10124163 DOI: 10.1016/j.mcn.2022.103770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/12/2022] [Accepted: 08/20/2022] [Indexed: 12/30/2022] Open
Abstract
Many neurodegenerative diseases have a multifactorial etiology and variable course of progression that cannot be explained by current models. Neurotropic viruses have long been suggested to play a role in these diseases, although their exact contributions remain unclear. Human herpesvirus 6A (HHV-6A) is one of the most common viruses detected in the adult brain, and has been clinically associated with multiple sclerosis (MS), and, more recently, Alzheimer's disease (AD). HHV-6A is a ubiquitous viral pathogen capable of infecting glia and neurons. Primary infection in childhood is followed by the induction of latency, characterized by expression of the U94A viral transcript in the absence of viral replication. Here we examine the effects of U94A on cells of the central nervous system. We found that U94A expression inhibits the migration and impairs cytoplasmic maturation of human oligodendrocyte precursor cells (OPCs) without affecting their viability, a phenotype that may contribute to the failure of remyelination seen in many patients with MS. A subsequent proteomics analysis of U94A expression OPCs revealed altered expression of genes involved in tubulin associated cytoskeletal regulation. As HHV-6A seems to significantly be associated with early AD pathology, we extended our initially analysis of the impact of U94A on human derived neurons. We found that U94A expression inhibits neurite outgrowth of primary human cortical neurons and impairs synapse maturation. Based on these data we suggest that U94A expression by latent HHV-6A in glial cells and neurons renders them susceptible to dysfunction and degeneration. Therefore, latent viral infections of the brain represent a unique pathological risk factor that may contribute to disease processes.
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Affiliation(s)
- Jessica M Hogestyn
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Garrick Salois
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Li Xie
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Connor Apa
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Stem cell and Regenerative Medicine Institute, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Justin Youngyunpipatkul
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Christoph Pröschel
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Stem cell and Regenerative Medicine Institute, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Margot Mayer-Pröschel
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA,.
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Inherited Chromosomally Integrated Human Herpesvirus 6 Demonstrates Tissue-Specific RNA Expression In Vivo That Correlates with an Increased Antibody Immune Response. J Virol 2019; 94:JVI.01418-19. [PMID: 31597766 PMCID: PMC6912112 DOI: 10.1128/jvi.01418-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 09/30/2019] [Indexed: 12/11/2022] Open
Abstract
HHV-6A and -6B are human herpesviruses that have the unique property of being able to integrate into the telomeric regions of human chromosomes. Approximately 1% of the world’s population carries integrated HHV-6A/B genome in every cell of their body. Whether viral genes are transcriptionally active in these individuals is unclear. By taking advantage of a unique tissue-specific gene expression data set, we showed that the majority of tissues from iciHHV-6 individuals do not show HHV-6 gene expression. Brain and testes showed the highest tissue-specific expression of HHV-6 genes in two separate data sets. Two HHV-6 genes, U90 (immediate early 1 protein) and U100 (glycoproteins Q1 and Q2), were found to be selectively and consistently expressed across several human tissues. Expression of U90 translates into an increase in antigen-specific antibody response in iciHHV-6A/B+ subjects relative to controls. Future studies will be needed to determine the mechanism of gene expression, the effects of these genes on human gene transcription networks, and the pathophysiological impact of having increased viral protein expression in tissue in conjunction with increased antigen-specific antibody production. Human herpesviruses 6A and 6B (HHV-6A and HHV-6B) are human viruses capable of chromosomal integration. Approximately 1% of the human population carries one copy of HHV-6A/B integrated into every cell in their body, referred to as inherited chromosomally integrated human herpesvirus 6A/B (iciHHV-6A/B). Whether iciHHV-6A/B is transcriptionally active in vivo and how it shapes the immunological response are still unclear. In this study, we screened DNA sequencing (DNA-seq) and transcriptome sequencing (RNA-seq) data for 650 individuals available through the Genotype-Tissue Expression (GTEx) project and identified 2 iciHHV-6A- and 4 iciHHV-6B-positive candidates. When corresponding tissue-specific gene expression signatures were analyzed, low levels HHV-6A/B gene expression was found across multiple tissues, with the highest levels of gene expression in the brain (specifically for HHV-6A), testis, esophagus, and adrenal gland. U90 and U100 were the most highly expressed HHV-6 genes in both iciHHV-6A- and iciHHV-6B-positive individuals. To assess whether tissue-specific gene expression from iciHHV-6A/B influences the immune response, a cohort of 15,498 subjects was screened and 85 iciHHV-6A/B+ subjects were identified. Plasma samples from iciHHV-6A/B+ and age- and sex-matched controls were analyzed for antibodies to control antigens (cytomegalovirus [CMV], Epstein-Barr virus [EBV], and influenza virus [FLU]) or HHV-6A/B antigens. Our results indicate that iciHHV-6A/B+ subjects have significantly more antibodies against the U90 gene product (IE1) than do non-iciHHV-6-positive individuals. Antibody responses against EBV and FLU antigens or HHV-6A/B gene products either not expressed or expressed at low levels, such as U47, U57, and U72, were identical between controls and iciHHV-6A/B+ subjects. CMV-seropositive individuals with iciHHV-6A/B+ have more antibodies against CMV pp150 than do CMV-seropositive controls. These results argue that spontaneous gene expression from integrated HHV-6A/B leads to an increase in antigenic burden that translates into a more robust HHV-6A/B-specific antibody response. IMPORTANCE HHV-6A and -6B are human herpesviruses that have the unique property of being able to integrate into the telomeric regions of human chromosomes. Approximately 1% of the world’s population carries integrated HHV-6A/B genome in every cell of their body. Whether viral genes are transcriptionally active in these individuals is unclear. By taking advantage of a unique tissue-specific gene expression data set, we showed that the majority of tissues from iciHHV-6 individuals do not show HHV-6 gene expression. Brain and testes showed the highest tissue-specific expression of HHV-6 genes in two separate data sets. Two HHV-6 genes, U90 (immediate early 1 protein) and U100 (glycoproteins Q1 and Q2), were found to be selectively and consistently expressed across several human tissues. Expression of U90 translates into an increase in antigen-specific antibody response in iciHHV-6A/B+ subjects relative to controls. Future studies will be needed to determine the mechanism of gene expression, the effects of these genes on human gene transcription networks, and the pathophysiological impact of having increased viral protein expression in tissue in conjunction with increased antigen-specific antibody production.
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Eliassen E, Lum E, Pritchett J, Ongradi J, Krueger G, Crawford JR, Phan TL, Ablashi D, Hudnall SD. Human Herpesvirus 6 and Malignancy: A Review. Front Oncol 2018; 8:512. [PMID: 30542640 PMCID: PMC6277865 DOI: 10.3389/fonc.2018.00512] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/19/2018] [Indexed: 12/21/2022] Open
Abstract
In order to determine the role of human herpesvirus 6 (HHV-6) in human disease, several confounding factors, including methods of detection, types of controls, and the ubiquitous nature of the virus, must be considered. This is particularly problematic in the case of cancer, in which rates of detection vary greatly among studies. To determine what part, if any, HHV-6 plays in oncogenesis, a review of the literature was performed. There is evidence that HHV-6 is present in certain types of cancer; however, detection of the virus within tumor cells is insufficient for assigning a direct role of HHV-6 in tumorigenesis. Findings supportive of a causal role for a virus in cancer include presence of the virus in a large proportion of cases, presence of the virus in most tumor cells, and virus-induced in-vitro cell transformation. HHV-6, if not directly oncogenic, may act as a contributory factor that indirectly enhances tumor cell growth, in some cases by cooperation with other viruses. Another possibility is that HHV-6 may merely be an opportunistic virus that thrives in the immunodeficient tumor microenvironment. Although many studies have been carried out, it is still premature to definitively implicate HHV-6 in several human cancers. In some instances, evidence suggests that HHV-6 may cooperate with other viruses, including EBV, HPV, and HHV-8, in the development of cancer, and HHV-6 may have a role in such conditions as nodular sclerosis Hodgkin lymphoma, gastrointestinal cancer, glial tumors, and oral cancers. However, further studies will be required to determine the exact contributions of HHV-6 to tumorigenesis.
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Affiliation(s)
- Eva Eliassen
- HHV-6 Foundation, Santa Barbara, CA, United States
| | - Emily Lum
- HHV-6 Foundation, Santa Barbara, CA, United States
| | - Joshua Pritchett
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States
| | - Joseph Ongradi
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
| | - Gerhard Krueger
- Department of Pathology and Laboratory Medicine, University of Texas- Houston Medical School, Houston, TX, United States
| | - John R Crawford
- Department of Neurosciences and Pediatrics, University of California San Diego and Rady Children's Hospital, San Diego, CA, United States
| | - Tuan L Phan
- HHV-6 Foundation, Santa Barbara, CA, United States.,Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States
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Eliassen E, Krueger G, Luppi M, Ablashi D. Lymphoproliferative Syndromes Associated with Human Herpesvirus-6A and Human Herpesvirus-6B. Mediterr J Hematol Infect Dis 2018; 10:e2018035. [PMID: 29755712 PMCID: PMC5937953 DOI: 10.4084/mjhid.2018.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 12/28/2022] Open
Abstract
Human herpesvirus 6A and 6B (HHV-6A and HHV-6B) have been noted since their discovery for their T-lymphotropism. Although it has proven difficult to determine the extent to which HHV-6A and HHV-6B are involved in the pathogenesis of many diseases, evidence suggests that primary infection and reactivation of both viruses may induce or contribute to the progression of several lymphoproliferative disorders, ranging from benign to malignant and including infectious mononucleosis-like illness, drug induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS), and nodular sclerosis Hodgkin's lymphoma. Herein, we discuss the conditions associated with the lymphoproliferative capacity of HHV-6, as well as the potential mechanisms behind them. Continued exploration on this topic may add to our understanding of the interactions between HHV-6 and the immune system and may open the doors to more accurate diagnosis and treatment of certain lymphoproliferative disorders.
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Affiliation(s)
- Eva Eliassen
- HHV-6 Foundation, Santa Barbara, California, USA
| | - Gerhard Krueger
- Department of Pathology and Laboratory Medicine, University of Texas, Houston, Texas, USA
| | - Mario Luppi
- Department of Medical and Surgical Sciences, University of Modena and Reggio Emilia, Modena, Italy
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Wood ML, Royle NJ. Chromosomally Integrated Human Herpesvirus 6: Models of Viral Genome Release from the Telomere and Impacts on Human Health. Viruses 2017; 9:E184. [PMID: 28704957 PMCID: PMC5537676 DOI: 10.3390/v9070184] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 12/11/2022] Open
Abstract
Human herpesvirus 6A and 6B, alongside some other herpesviruses, have the striking capacity to integrate into telomeres, the terminal repeated regions of chromosomes. The chromosomally integrated forms, ciHHV-6A and ciHHV-6B, are proposed to be a state of latency and it has been shown that they can both be inherited if integration occurs in the germ line. The first step in full viral reactivation must be the release of the integrated viral genome from the telomere and here we propose various models of this release involving transcription of the viral genome, replication fork collapse, and t-circle mediated release. In this review, we also discuss the relationship between ciHHV-6 and the telomere carrying the insertion, particularly how the presence and subsequent partial or complete release of the ciHHV-6 genome may affect telomere dynamics and the risk of disease.
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Affiliation(s)
- Michael L Wood
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Nicola J Royle
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK.
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