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Bahramian E, Furr M, Wu JT, Ceballos RM. Differential Impacts of HHV-6A versus HHV-6B Infection in Differentiated Human Neural Stem Cells. Front Immunol 2022; 13:847106. [PMID: 35911725 PMCID: PMC9326508 DOI: 10.3389/fimmu.2022.847106] [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: 01/01/2022] [Accepted: 06/16/2022] [Indexed: 12/02/2022] Open
Abstract
Within the family Herpesviridae, sub-family β-herpesvirinae, and genus Roseolovirus, there are only three human herpesviruses that have been described: HHV-6A, HHV-6B, and HHV-7. Initially, HHV-6A and HHV-6B were considered as two variants of the same virus (i.e., HHV6). Despite high overall genetic sequence identity (~90%), HHV-6A and HHV-6B are now recognized as two distinct viruses. Sequence divergence (e.g., >30%) in key coding regions and significant differences in physiological and biochemical profiles (e.g., use of different receptors for viral entry) underscore the conclusion that HHV-6A and HHV-6B are distinct viruses of the β-herpesvirinae. Despite these viruses being implicated as causative agents in several nervous system disorders (e.g., multiple sclerosis, epilepsy, and chronic fatigue syndrome), the mechanisms of action and relative contributions of each virus to neurological dysfunction are unclear. Unresolved questions regarding differences in cell tropism, receptor use and binding affinity (i.e., CD46 versus CD134), host neuro-immunological responses, and relative virulence between HHV-6A versus HHV-6B prevent a complete characterization. Although it has been shown that both HHV-6A and HHV-6B can infect glia (and, recently, cerebellar Purkinje cells), cell tropism of HHV-6A versus HHV-6B for different nerve cell types remains vague. In this study, we show that both viruses can infect different nerve cell types (i.e., glia versus neurons) and different neurotransmitter phenotypes derived from differentiated human neural stem cells. As demonstrated by immunofluorescence, HHV-6A and HHV-6B productively infect VGluT1-containing cells (i.e., glutamatergic neurons) and dopamine-containing cells (i.e., dopaminergic neurons). However, neither virus appears to infect GAD67-containing cells (i.e., GABAergic neurons). As determined by qPCR, expression of immunological factors (e.g., cytokines) in cells infected with HHV-6A versus HHV6-B also differs. These data along with morphometric and image analyses of infected differentiated neural stem cell cultures indicate that while HHV-6B may have greater opportunity for transmission, HHV-6A induces more severe cytopathic effects (e.g., syncytia) at the same post-infection end points. Cumulatively, results suggest that HHV-6A is more virulent than HHV-6B in susceptible cells, while neither virus productively infects GABAergic cells. Consistency between these in vitro data and in vivo experiments would provide new insights into potential mechanisms for HHV6-induced epileptogenesis.
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Affiliation(s)
- Elham Bahramian
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, United States
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
| | - Mercede Furr
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Jerry T. Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Ruben Michael Ceballos
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, United States
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Ecology, Evolution, and Organismal Biology Group, University of Arkansas, Fayetteville, AR, United States
- Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Ruben Michael Ceballos,
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Evasion of the Host Immune Response by Betaherpesviruses. Int J Mol Sci 2021; 22:ijms22147503. [PMID: 34299120 PMCID: PMC8306455 DOI: 10.3390/ijms22147503] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/11/2021] [Accepted: 07/12/2021] [Indexed: 02/07/2023] Open
Abstract
The human immune system boasts a diverse array of strategies for recognizing and eradicating invading pathogens. Human betaherpesviruses, a highly prevalent subfamily of viruses, include human cytomegalovirus (HCMV), human herpesvirus (HHV) 6A, HHV-6B, and HHV-7. These viruses have evolved numerous mechanisms for evading the host response. In this review, we will highlight the complex interplay between betaherpesviruses and the human immune response, focusing on protein function. We will explore methods by which the immune system first responds to betaherpesvirus infection as well as mechanisms by which viruses subvert normal cellular functions to evade the immune system and facilitate viral latency, persistence, and reactivation. Lastly, we will briefly discuss recent advances in vaccine technology targeting betaherpesviruses. This review aims to further elucidate the dynamic interactions between betaherpesviruses and the human immune system.
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Mysore KR, Phan TL, Himes RW, Schady D, Eldin KW, Prusty BK, Munoz FM. Human Herpesvirus 6 Infection in Pediatric Liver Transplantation: Single-Center Study of Incidence, Outcomes, and Management. J Pediatric Infect Dis Soc 2021; 10:599-606. [PMID: 33491073 PMCID: PMC8163056 DOI: 10.1093/jpids/piaa166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 12/29/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Distinctions between HHV-6 primary infection in seronegative patients and HHV-6 reactivation in seropositive patients remains largely undescribed in pediatric liver transplant (LT) recipients. METHODS We implemented pretransplant serology testing of HHV-6 in a large pediatric hospital and retrospectively assessed the incidence, manifestations and outcomes of HHV-6 infections over a 3-year period. RESULTS Among 101 pediatric LT recipients, 96 had pretransplant HHV-6 serologies; 34 (35.4%) were seronegative and 62 (64.6%) seropositive. Posttransplantation, 8/25 (32%) seronegative patients had HHV-6 DNAemia (primary infection) compared to 2/48 (4%) seropositive patients (p=0.002). Compared to seropositive patients, seronegative patients with HHV-6 DNAemia were younger, and had symptoms of fever and/or elevated aminotransferases in association with higher viral loads, in the first month post-transplant. More than 90% of seronegative patients and 77.8% of seropositive patients had HHV-6 detected by PCR in liver biopsy obtained for concerns of allograft rejection, but most had no detectable concomitant DNAemia. Active replication of virus in the liver was confirmed by in situ hybridization in select cases. While HHV-6 infection occurred among patients on prophylaxis doses of antivirals for CMV, HHV-6 DNAemia and presenting symptoms resolved on treatment doses. CONCLUSIONS HHV-6 DNA-emia occurred more frequently in seronegative pediatric LT recipients, usually in the early posttransplant period, and was subsequently detected in allograft biopsies. HHV-6 cannot be ruled out as a cause of hepatitis in the absence of allograft tissue testing and specialized virological assays, as HHV-6 may disrupt local allograft immune homeostasis while evading traditional screening methods using blood or plasma. The assessment of pre-transplant HHV-6 serological status may be important for risk stratification and post-transplant management of pediatric LT recipients.
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Affiliation(s)
- Krupa R Mysore
- Department of Pediatrics, Section of Pediatric Gastroenterology, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA,Corresponding Author: Krupa R. Mysore, MD, MS, Section of Gastroenterology Hepatology & Nutrition, Texas Children’s Hospital, Baylor College of Medicine, 6701 Fannin St. Suite 1010, Houston, TX 77030, USA. E-mail:
| | - Tuan L Phan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA,HHV-6 Foundation, Santa Barbara, California, USA
| | - Ryan W Himes
- Department of Pediatrics, Section of Gastroenterology & Hepatology, Ochsner Medical Center, New Orleans, Louisiana, USA
| | - Deborah Schady
- Department of Pathology, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Karen W Eldin
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Bhupesh K Prusty
- Institut für Virologie und Immunobiologie, Julius-Maximilians Universität Würzburg, Würzburg, Germany
| | - Flor M Munoz
- Department of Pediatrics, Section of Infectious Diseases, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA
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Abstract
The human betaherpesviruses, human cytomegalovirus (HCMV; species Human betaherpesvirus 5) and human herpesviruses 6A, 6B, and 7 (HHV-6A, -6B, and -7; species Human betaherpesviruses 6A, 6B, and 7) are highly prevalent and can cause severe disease in immune-compromised and immune-naive populations in well- and under-developed communities. Herpesvirus virion assembly is an intricate process that requires viral orchestration of host systems. In this review, we describe recent advances in some of the many cellular events relevant to assembly and egress of betaherpesvirus virions. These include modifications of host metabolic, immune, and autophagic/recycling systems. In addition, we discuss unique aspects of betaherpesvirus virion structure, virion assembly, and the cellular pathways employed during virion egress.
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Denner J, Bigley TM, Phan TL, Zimmermann C, Zhou X, Kaufer BB. Comparative Analysis of Roseoloviruses in Humans, Pigs, Mice, and Other Species. Viruses 2019; 11:E1108. [PMID: 31801268 PMCID: PMC6949924 DOI: 10.3390/v11121108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/13/2019] [Accepted: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
Viruses of the genus Roseolovirus belong to the subfamily Betaherpesvirinae, family Herpesviridae. Roseoloviruses have been studied in humans, mice and pigs, but they are likely also present in other species. This is the first comparative analysis of roseoloviruses in humans and animals. The human roseoloviruses human herpesvirus 6A (HHV-6A), 6B (HHV-6B), and 7 (HHV-7) are relatively well characterized. In contrast, little is known about the murine roseolovirus (MRV), also known as murine thymic virus (MTV) or murine thymic lymphotrophic virus (MTLV), and the porcine roseolovirus (PRV), initially incorrectly named porcine cytomegalovirus (PCMV). Human roseoloviruses have gained attention because they can cause severe diseases including encephalitis in immunocompromised transplant and AIDS patients and febrile seizures in infants. They have been linked to a number of neurological diseases in the immunocompetent including multiple sclerosis (MS) and Alzheimer's. However, to prove the causality in the latter disease associations is challenging due to the high prevalence of these viruses in the human population. PCMV/PRV has attracted attention because it may be transmitted and pose a risk in xenotransplantation, e.g., the transplantation of pig organs into humans. Most importantly, all roseoloviruses are immunosuppressive, the humoral and cellular immune responses against these viruses are not well studied and vaccines as well as effective antivirals are not available.
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Affiliation(s)
- Joachim Denner
- Robert Koch Institute, Robert Koch Fellow, 13352 Berlin, Germany
| | - Tarin M. Bigley
- Division of Rheumatology, Department. of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA;
| | - Tuan L. Phan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70118, USA;
- HHV-6 Foundation, Santa Barbara, CA 93108, USA
| | - Cosima Zimmermann
- Institute of Virology, Freie Universität Berlin, 14163 Berlin, Germany;
| | - Xiaofeng Zhou
- Division of Pulmonary and Critical Care Medicine, Department. of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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