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Gutowska A, Sarkis S, Rahman MA, Goldfarbmuren KC, Moles R, Bissa M, Doster M, Washington-Parks R, McKinnon K, Silva de Castro I, Schifanella L, Franchini G, Pise-Masison CA. Complete Rescue of HTLV-1 p12KO Infectivity by Depletion of Monocytes Together with NK and CD8 + T Cells. Pathogens 2024; 13:292. [PMID: 38668247 PMCID: PMC11054408 DOI: 10.3390/pathogens13040292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 04/29/2024] Open
Abstract
The transient depletion of monocytes alone prior to exposure of macaques to HTLV-1 enhances both HTLV-1WT (wild type) and HTLV-1p12KO (Orf-1 knockout) infectivity, but seroconversion to either virus is not sustained over time, suggesting a progressive decrease in virus expression. These results raise the hypotheses that either HTLV-1 persistence depends on a monocyte reservoir or monocyte depletion provides a transient immune evasion benefit. To test these hypotheses, we simultaneously depleted NK cells, CD8+ T cells, and monocytes (triple depletion) prior to exposure to HTLV-1WT or HTLV-1p12KO. Remarkably, triple depletion resulted in exacerbation of infection by both viruses and complete rescue of HTLV-1p12KO infectivity. Following triple depletion, we observed rapid and sustained seroconversion, high titers of antibodies against HTLV-1 p24Gag, and frequent detection of viral DNA in the blood and tissues of all animals when compared with depletion of only CD8+ and NK cells, or monocytes alone. The infection of macaques with HTLV-1WT or HTLV-1p12KO was associated with higher plasma levels of IL-10 after 21 weeks, while IL-6, IFN-γ, IL-18, and IL-1β were only elevated in animals infected with HTLV-1WT. The repeat depletion of monocytes, NK, and CD8+ cells seven months following the first exposure to HTLV-1 did not further exacerbate viral replication. These results underscore the contribution of monocytes in orchestrating anti-viral immunity. Indeed, the absence of orf-1 expression was fully compensated by the simultaneous depletion of CD8+ T cells, NK cells, and monocytes, underlining the primary role of orf-1 in hijacking host immunity.
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Affiliation(s)
- Anna Gutowska
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Mohammad Arif Rahman
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Katherine C. Goldfarbmuren
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA;
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Ramona Moles
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Massimiliano Bissa
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Melvin Doster
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Robyn Washington-Parks
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Katherine McKinnon
- Vaccine Branch Flow Cytometry Core, National Cancer Institute, Bethesda, MD 20892, USA;
| | - Isabela Silva de Castro
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Luca Schifanella
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
| | - Cynthia A. Pise-Masison
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; (A.G.); (S.S.); (I.S.d.C.)
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Mohan AG, Calenic B, Ghiurau NA, Duncea-Borca RM, Constantinescu AE, Constantinescu I. The Golgi Apparatus: A Voyage through Time, Structure, Function and Implication in Neurodegenerative Disorders. Cells 2023; 12:1972. [PMID: 37566051 PMCID: PMC10417163 DOI: 10.3390/cells12151972] [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: 06/14/2023] [Revised: 07/27/2023] [Accepted: 07/29/2023] [Indexed: 08/12/2023] Open
Abstract
This comprehensive review article dives deep into the Golgi apparatus, an essential organelle in cellular biology. Beginning with its discovery during the 19th century until today's recognition as an important contributor to cell function. We explore its unique organization and structure as well as its roles in protein processing, sorting, and lipid biogenesis, which play key roles in maintaining homeostasis in cellular biology. This article further explores Golgi biogenesis, exploring its intricate processes and dynamics that contribute to its formation and function. One key focus is its role in neurodegenerative diseases like Parkinson's, where changes to the structure or function of the Golgi apparatus may lead to their onset or progression, emphasizing its key importance in neuronal health. At the same time, we examine the intriguing relationship between Golgi stress and endoplasmic reticulum (ER) stress, providing insights into their interplay as two major cellular stress response pathways. Such interdependence provides a greater understanding of cellular reactions to protein misfolding and accumulation, hallmark features of many neurodegenerative diseases. In summary, this review offers an exhaustive examination of the Golgi apparatus, from its historical background to its role in health and disease. Additionally, this examination emphasizes the necessity of further research in this field in order to develop targeted therapeutic approaches for Golgi dysfunction-associated conditions. Furthermore, its exploration is an example of scientific progress while simultaneously offering hope for developing innovative treatments for neurodegenerative disorders.
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Affiliation(s)
- Aurel George Mohan
- Department of Neurosurgery, Bihor County Emergency Clinical Hospital, 410167 Oradea, Romania;
- Faculty of Medicine, Oradea University, 410610 Oradea, Romania
| | - Bogdan Calenic
- Immunology and Transplant Immunology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania;
- Centre of Immunogenetics and Virology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Nicu Adrian Ghiurau
- Department of Surgical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, 410610 Oradea, Romania;
| | | | | | - Ileana Constantinescu
- Immunology and Transplant Immunology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania;
- Centre of Immunogenetics and Virology, Fundeni Clinical Institute, 022328 Bucharest, Romania
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3
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Michalak M. Calreticulin: Endoplasmic reticulum Ca 2+ gatekeeper. J Cell Mol Med 2023; 28:e17839. [PMID: 37424156 PMCID: PMC10902585 DOI: 10.1111/jcmm.17839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/21/2023] [Accepted: 06/27/2023] [Indexed: 07/11/2023] Open
Abstract
Endoplasmic reticulum (ER) luminal Ca2+ is vital for the function of the ER and regulates many cellular processes. Calreticulin is a highly conserved, ER-resident Ca2+ binding protein and lectin-like chaperone. Over four decades of studying calreticulin demonstrate that this protein plays a crucial role in maintaining Ca2+ supply under different physiological conditions, in managing access to Ca2+ and how Ca2+ is used depending on the environmental events and in making sure that Ca2+ is not misused. Calreticulin plays a role of ER luminal Ca2+ sensor to manage Ca2+ -dependent ER luminal events including maintaining interaction with its partners, Ca2+ handling molecules, substrates and stress sensors. The protein is strategically positioned in the lumen of the ER from where the protein manages access to and distribution of Ca2+ for many cellular Ca2+ -signalling events. The importance of calreticulin Ca2+ pool extends beyond the ER and includes influence of cellular processes involved in many aspects of cellular pathophysiology. Abnormal handling of the ER Ca2+ contributes to many pathologies from heart failure to neurodegeneration and metabolic diseases.
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Affiliation(s)
- Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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4
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Aristodemou AEN, Rueda DS, Taylor GP, Bangham CRM. The transcriptome of HTLV-1-infected primary cells following reactivation reveals changes to host gene expression central to the proviral life cycle. PLoS Pathog 2023; 19:e1011494. [PMID: 37523412 PMCID: PMC10431621 DOI: 10.1371/journal.ppat.1011494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 08/16/2023] [Accepted: 06/19/2023] [Indexed: 08/02/2023] Open
Abstract
Infections by Human T cell Leukaemia Virus type 1 (HTLV-1) persist for the lifetime of the host by integrating into the genome of CD4+ T cells. Proviral gene expression is essential for proviral survival and the maintenance of the proviral load, through the pro-proliferative changes it induces in infected cells. Despite their role in HTLV-1 infection and a persistent cytotoxic T lymphocyte response raised against the virus, proviral transcripts from the sense-strand are rarely detected in fresh cells extracted from the peripheral blood, and have recently been found to be expressed intermittently by a small subset of cells at a given time. Ex vivo culture of infected cells prompts synchronised proviral expression in infected cells from peripheral blood, allowing the study of factors involved in reactivation in primary cells. Here, we used bulk RNA-seq to examine the host transcriptome over six days in vitro, following proviral reactivation in primary peripheral CD4+ T cells isolated from subjects with non-malignant HTLV-1 infection. Infected cells displayed a conserved response to reactivation, characterised by discrete stages of gene expression, cell division and subsequently horizontal transmission of the virus. We observed widespread changes in Polycomb gene expression following reactivation, including an increase in PRC2 transcript levels and diverse changes in the expression of PRC1 components. We hypothesize that these transcriptional changes constitute a negative feedback loop that maintains proviral latency by re-deposition of H2AK119ub1 following the end of proviral expression. Using RNAi, we found that certain deubiquitinases, BAP1, USP14 and OTUD5 each promote proviral transcription. These data demonstrate the detailed trajectory of HTLV-1 proviral reactivation in primary HTLV-1-carrier lymphocytes and the impact on the host cell.
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Affiliation(s)
- Aris E. N. Aristodemou
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - David S. Rueda
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, United Kingdom
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, United Kingdom
| | - Graham P. Taylor
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Charles R. M. Bangham
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, United Kingdom
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5
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Pise-Masison CA, Franchini G. Hijacking Host Immunity by the Human T-Cell Leukemia Virus Type-1: Implications for Therapeutic and Preventive Vaccines. Viruses 2022; 14:2084. [PMID: 36298639 PMCID: PMC9609126 DOI: 10.3390/v14102084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2024] Open
Abstract
Human T-cell Leukemia virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other inflammatory diseases. High viral DNA burden (VL) in peripheral blood mononuclear cells is a documented risk factor for ATLL and HAM/TSP, and patients with HAM/TSP have a higher VL in cerebrospinal fluid than in peripheral blood. VL alone is not sufficient to differentiate symptomatic patients from healthy carriers, suggesting the importance of other factors, including host immune response. HTLV-1 infection is life-long; CD4+-infected cells are not eradicated by the immune response because HTLV-1 inhibits the function of dendritic cells, monocytes, Natural Killer cells, and adaptive cytotoxic CD8+ responses. Although the majority of infected CD4+ T-cells adopt a resting phenotype, antigen stimulation may result in bursts of viral expression. The antigen-dependent "on-off" viral expression creates "conditional latency" that when combined with ineffective host responses precludes virus eradication. Epidemiological and clinical data suggest that the continuous attempt of the host immunity to eliminate infected cells results in chronic immune activation that can be further exacerbated by co-morbidities, resulting in the development of severe disease. We review cell and animal model studies that uncovered mechanisms used by HTLV-1 to usurp and/or counteract host immunity.
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Affiliation(s)
- Cynthia A. Pise-Masison
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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6
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Moles R, Sarkis S, Galli V, Omsland M, Artesi M, Bissa M, McKinnon K, Brown S, Hahaut V, Washington-Parks R, Welsh J, Venzon DJ, Gutowska A, Doster MN, Breed MW, Killoran KE, Kramer J, Jones J, Moniuszko M, Van den Broeke A, Pise-Masison CA, Franchini G. NK cells and monocytes modulate primary HTLV-1 infection. PLoS Pathog 2022; 18:e1010416. [PMID: 35377924 PMCID: PMC9022856 DOI: 10.1371/journal.ppat.1010416] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 04/21/2022] [Accepted: 03/04/2022] [Indexed: 12/21/2022] Open
Abstract
We investigated the impact of monocytes, NK cells, and CD8+ T-cells in primary HTLV-1 infection by depleting cell subsets and exposing macaques to either HTLV-1 wild type (HTLV-1WT) or to the HTLV-1p12KO mutant unable to infect replete animals due to a single point mutation in orf-I that inhibits its expression. The orf-I encoded p8/p12 proteins counteract cytotoxic NK and CD8+ T-cells and favor viral DNA persistence in monocytes. Double NK and CD8+ T-cells or CD8 depletion alone accelerated seroconversion in all animals exposed to HTLV-1WT. In contrast, HTLV-1p12KO infectivity was fully restored only when NK cells were also depleted, demonstrating a critical role of NK cells in primary infection. Monocyte/macrophage depletion resulted in accelerated seroconversion in all animals exposed to HTLV-1WT, but antibody titers to the virus were low and not sustained. Seroconversion did not occur in most animals exposed to HTLV-1p12KO.In vitro experiments in human primary monocytes or THP-1 cells comparing HTLV-1WT and HTLV-1p12KO demonstrated that orf-I expression is associated with inhibition of inflammasome activation in primary cells, with increased CD47 “don’t-eat-me” signal surface expression in virus infected cells and decreased monocyte engulfment of infected cells. Collectively, our data demonstrate a critical role for innate NK cells in primary infection and suggest a dual role of monocytes in primary infection. On one hand, orf-I expression increases the chances of viral transmission by sparing infected cells from efferocytosis, and on the other may protect the engulfed infected cells by modulating inflammasome activation. These data also suggest that, once infection is established, the stoichiometry of orf-I expression may contribute to the chronic inflammation observed in HTLV-1 infection by modulating monocyte efferocytosis. The immune cells that inhibit or favor HTLV-1 infection are still unknown and their identification is critical for understanding viral pathogenesis and for the development of an effective HTLV-1 vaccine. Neutralizing antibodies are produced in natural HTLV-1 infection, but their impact is likely hampered by the virus’s ability to be transmitted from cell to cell via the virological synapse, cellular conduits, and biofilms. By depleting specific immune cell subsets in blood, we found that NK cells play a critical role in the containment of early HTLV-1 infection. Moreover, transient depletion of monocytes/macrophages results in early, but not sustained seroconversion, suggesting that early engagement of monocytes may be necessary for long-term productive infection. The engulfment of apoptotic T-cells infected by HTLV-1 may represent a viral strategy to persist in the host since the viral proteins encoded by orf-I and orf-II affect the function of receptors and proteins involved in efferocytosis. These results suggest that effective HTLV-1 vaccines must also elicit durable innate responses able to promptly clear virus invasion of monocytes through engulfment of infected T-cells to avoid the establishment of a vicious cycle that leads to chronic inflammation.
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Affiliation(s)
- Ramona Moles
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Veronica Galli
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Maria Omsland
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Maria Artesi
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
- Unit of Animal Genomics, GIGA, Université de Liège, Liège, Belgium
| | - Massimiliano Bissa
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Katherine McKinnon
- Vaccine Branch Flow Cytometry Core, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sophia Brown
- Vaccine Branch Flow Cytometry Core, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Vincent Hahaut
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
- Unit of Animal Genomics, GIGA, Université de Liège, Liège, Belgium
| | - Robyn Washington-Parks
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Joshua Welsh
- Translational Nanobiology Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - David J. Venzon
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Anna Gutowska
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Melvin N. Doster
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Matthew W. Breed
- Laboratory Animal Sciences Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Kristin E. Killoran
- Laboratory Animal Sciences Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Joshua Kramer
- Laboratory Animal Sciences Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Jennifer Jones
- Translational Nanobiology Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Marcin Moniuszko
- Department of Allergology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland
| | - Anne Van den Broeke
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
- Unit of Animal Genomics, GIGA, Université de Liège, Liège, Belgium
| | - Cynthia A. Pise-Masison
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail:
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7
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Regulation of HTLV-1 Transformation. Biosci Rep 2022; 42:230803. [PMID: 35169839 PMCID: PMC8919135 DOI: 10.1042/bsr20211921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/07/2022] [Accepted: 02/15/2022] [Indexed: 11/17/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the only identified oncogenic human retrovirus. HTLV-1 infects approximately 5–10 million people worldwide and is the infectious cause of adult T-cell leukemia/lymphoma (ATL) and several chronic inflammatory diseases, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), dermatitis, and uveitis. Unlike other oncogenic retroviruses, HTLV-1 does not capture a cellular proto-oncogene or induce proviral insertional mutagenesis. HTLV-1 is a trans-activating retrovirus and encodes accessory proteins that induce cellular transformation over an extended period of time, upwards of several years to decades. Inarguably the most important viral accessory protein involved in transformation is Tax. Tax is a multifunctional protein that regulates several different pathways and cellular processes. This single viral protein is able to modulate viral gene expression, activate NF-κB signaling pathways, deregulate the cell cycle, disrupt apoptosis, and induce genomic instability. The summation of these processes results in cellular transformation and virus-mediated oncogenesis. Interestingly, HTLV-1 also encodes a protein called Hbz from the antisense strand of the proviral genome that counters many Tax functions in the infected cell, such as Tax-mediated viral transcription and NF-κB activation. However, Hbz also promotes cellular proliferation, inhibits apoptosis, and disrupts genomic integrity. In addition to viral proteins, there are other cellular factors such as MEF-2, superoxide-generating NAPDH oxidase 5-α (Nox5α), and PDLIM2 which have been shown to be critical for HTLV-1-mediated T-cell transformation. This review will highlight the important viral and cellular factors involved in HTLV-1 transformation and the available in vitro and in vivo tools used to study this complex process.
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8
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Chen Q, Coto-Llerena M, Suslov A, Teixeira RD, Fofana I, Nuciforo S, Hofmann M, Thimme R, Hensel N, Lohmann V, Ng CKY, Rosenberger G, Wieland S, Heim MH. Interferon lambda 4 impairs hepatitis C viral antigen presentation and attenuates T cell responses. Nat Commun 2021; 12:4882. [PMID: 34385466 PMCID: PMC8360984 DOI: 10.1038/s41467-021-25218-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 07/26/2021] [Indexed: 12/15/2022] Open
Abstract
Genetic variants of the interferon lambda (IFNL) gene locus are strongly associated with spontaneous and IFN treatment-induced clearance of hepatitis C virus (HCV) infections. Individuals with the ancestral IFNL4-dG allele are not able to clear HCV in the acute phase and have more than a 90% probability to develop chronic hepatitis C (CHC). Paradoxically, the IFNL4-dG allele encodes a fully functional IFNλ4 protein with antiviral activity against HCV. Here we describe an effect of IFNλ4 on HCV antigen presentation. Only minor amounts of IFNλ4 are secreted, because the protein is largely retained in the endoplasmic reticulum (ER) where it induces ER stress. Stressed cells are significantly weaker activators of HCV specific CD8+ T cells than unstressed cells. This is not due to reduced MHC I surface presentation or extracellular IFNλ4 effects, since T cell responses are restored by exogenous loading of MHC with HCV antigens. Rather, IFNλ4 induced ER stress impairs HCV antigen processing and/or loading onto the MHC I complex. Our results provide a potential explanation for the IFNλ4-HCV paradox.
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Affiliation(s)
- Qian Chen
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Aleksei Suslov
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Isabel Fofana
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Sandro Nuciforo
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Maike Hofmann
- Department of Medicine II, University Hospital Freiburg, Freiburg, Germany
| | - Robert Thimme
- Department of Medicine II, University Hospital Freiburg, Freiburg, Germany
| | - Nina Hensel
- Department of Medicine II, University Hospital Freiburg, Freiburg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, Centre for Integrative Infectious Disease Research (CIID), University of Heidelberg, Heidelberg, Germany
| | - Charlotte K Y Ng
- Department for BioMedical Research (DBMR), Oncogenomics Lab, University of Bern, Bern, Switzerland
| | | | - Stefan Wieland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Markus H Heim
- Department of Biomedicine, University of Basel, Basel, Switzerland. .,Clarunis, University Center for Gastrointestinal and Liver Diseases, Basel, Switzerland.
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9
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Panda S, Behera S, Alam MF, Syed GH. Endoplasmic reticulum & mitochondrial calcium homeostasis: The interplay with viruses. Mitochondrion 2021; 58:227-242. [PMID: 33775873 DOI: 10.1016/j.mito.2021.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 03/08/2021] [Accepted: 03/22/2021] [Indexed: 02/08/2023]
Abstract
Calcium ions (Ca2+) act as secondary messengers in a plethora of cellular processes and play crucial role in cellular organelle function and homeostasis. The average resting concentration of Ca2+ is nearly 100 nM and in certain cells it can reach up to 1 µM. The high range of Ca2+ concentration across the plasma membrane and intracellular Ca2+ stores demands a well-coordinated maintenance of free Ca2+ via influx, efflux, buffering and storage. Endoplasmic Reticulum (ER) and Mitochondria depend on Ca2+ for their function and also serve as major players in intracellular Ca2+ homeostasis. The ER-mitochondria interplay helps in orchestrating cellular calcium homeostasis to avoid any detrimental effect resulting from Ca2+ overload or depletion. Since Ca2+ plays a central role in many biological processes it is an essential component of the virus-host interactions. The large gradient across membranes enable the viruses to easily modulate this buffered environment to meet their needs. Viruses exploit Ca2+ signaling to establish productive infection and evade the host immune defense. In this review we will detail the interplay between the viruses and cellular & ER-mitochondrial calcium signaling and the significance of these events on viral life cycle and disease pathogenesis.
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Affiliation(s)
- Swagatika Panda
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India
| | - Suchismita Behera
- Institute of Life Sciences, Bhubaneswar, Clinical Proteomics Laboratory, Institute of Life Sciences, Bhubaneswar, India
| | - Mohd Faraz Alam
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India
| | - Gulam Hussain Syed
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India.
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10
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Donhauser N, Socher E, Millen S, Heym S, Sticht H, Thoma-Kress AK. Transfer of HTLV-1 p8 and Gag to target T-cells depends on VASP, a novel interaction partner of p8. PLoS Pathog 2020; 16:e1008879. [PMID: 32997728 PMCID: PMC7526893 DOI: 10.1371/journal.ppat.1008879] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022] Open
Abstract
The Human T-cell leukemia virus type 1 (HTLV-1) orf I-encoded accessory protein p8 is cleaved from its precursor p12, and both proteins contribute to viral persistence. p8 induces cellular protrusions, which are thought to facilitate transfer of p8 to target cells and virus transmission. Host factors interacting with p8 and mediating p8 transfer are unknown. Here, we report that vasodilator-stimulated phosphoprotein (VASP), which promotes actin filament elongation, is a novel interaction partner of p8 and important for p8 and HTLV-1 Gag cell-to-cell transfer. VASP contains an Ena/VASP homology 1 (EVH1) domain that targets the protein to focal adhesions. Bioinformatics identified a short stretch in p8 (amino acids (aa) 24–45) which may mediate interactions with the EVH1 domain of VASP. Co-immunoprecipitations confirmed interactions of VASP:p8 in 293T, Jurkat and HTLV-1-infected MT-2 cells. Co-precipitation of VASP:p8 could be significantly blocked by peptides mimicking aa 26–37 of p8. Mutational studies revealed that the EVH1-domain of VASP is necessary, but not sufficient for the interaction with p8. Further, deletion of the VASP G- and F-actin binding domains significantly diminished co-precipitation of p8. Imaging identified areas of partial co-localization of VASP with p8 at the plasma membrane and in protrusive structures, which was confirmed by proximity ligation assays. Co-culture experiments revealed that p8 is transferred between Jurkat T-cells via VASP-containing conduits. Imaging and flow cytometry revealed that repression of both endogenous and overexpressed VASP by RNA interference or by CRISPR/Cas9 reduced p8 transfer to the cell surface and to target Jurkat T-cells. Stable repression of VASP by RNA interference in chronically infected MT-2 cells impaired both p8 and HTLV-1 Gag transfer to target Jurkat T-cells, while virus release was unaffected. Thus, we identified VASP as a novel interaction partner of p8, which is important for transfer of HTLV-1 p8 and Gag to target T-cells. The delta-retrovirus Human T-cell leukemia virus type 1 encodes the accessory protein p8, which is generated by proteolytic cleavage from p12. Earlier work has shown that p8 enhances the formation of cellular conduits between T-cells, is transferred through these conduits to target T-cells and increases HTLV-1 transmission. It was suggested that p8 dampens T-cell responses in target T-cells, thus facilitating HTLV-1 infection. Our work sheds light on the mechanism of p8 transfer to target T-cells. We show that vasodilator-stimulated phosphoprotein (VASP), a novel interaction partner of p8, contributes to transfer of p8 to target T-cells. Mechanistically, VASP is crucial for recruitment of p8 to the cell surface. Since VASP is known to promote elongation of actin filaments by preventing them from capping, interactions of p8 with VASP are an elegant strategy to exploit the host cell machinery for being transported to the cell surface, and as a consequence, to other cells. Given that VASP is also important for cell-to-cell transfer of the HTLV-1 Gag protein, our work proposes that VASP is a new cellular target to counteract HTLV-1 cell-to-cell transmission.
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Affiliation(s)
- Norbert Donhauser
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Eileen Socher
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sebastian Millen
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Stefanie Heym
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Andrea K. Thoma-Kress
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- * E-mail:
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11
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Hirons A, Khoury G, Purcell DFJ. Human T-cell lymphotropic virus type-1: a lifelong persistent infection, yet never truly silent. THE LANCET. INFECTIOUS DISEASES 2020; 21:e2-e10. [PMID: 32986997 DOI: 10.1016/s1473-3099(20)30328-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/06/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
Human T-cell lymphotropic virus type-1 (HTLV-1) has a large global burden and in some key communities, such as Indigenous Australians living in remote areas, greater than 45% of people are infected. Despite HTLV-1 causing serious malignancy and myelopathic paraparesis, and a significant association with a range of inflammatory comorbidities and secondary infections that shorten lifespan, few biomedical interventions are available. HTLV-1 starkly contrasts with other blood-borne sexually transmitted viral infections, such as, HIV, hepatitis B virus, and hepatitis C virus, with no antiviral treatments that reduce virus-infected cells, no rapid diagnostics or biomarker assays suitable for use in remote settings, and no effective vaccine. We review how the replication strategies and molecular properties of HTLV-1 establish a long-term stealthy viral pathogenesis through a fine-tuned balance of persistence, immune cell dysfunction, and proliferation of proviral infected cells that collectively present robust barriers to treatment and prevention. An understanding of the nature of the HTLV-1 provirus and opposing actions of viral-coded negative-sense HBZ and positive-sense regulatory proteins Tax, p12 and its cleaved product p8, and p30, is needed to improve the biomedical tools for preventing transmission and improving the long-term health of people with this lifelong infection.
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Affiliation(s)
- Ashley Hirons
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Georges Khoury
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Damian F J Purcell
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia.
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12
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Sarkis S, Galli V, Moles R, Yurick D, Khoury G, Purcell DFJ, Franchini G, Pise-Masison CA. Role of HTLV-1 orf-I encoded proteins in viral transmission and persistence. Retrovirology 2019; 16:43. [PMID: 31852543 PMCID: PMC6921521 DOI: 10.1186/s12977-019-0502-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023] Open
Abstract
The human T cell leukemia virus type 1 (HTVL-1), first reported in 1980 by Robert Gallo's group, is the etiologic agent of both cancer and inflammatory diseases. Despite approximately 40 years of investigation, the prognosis for afflicted patients remains poor with no effective treatments. The virus persists in the infected host by evading the host immune response and inducing proliferation of infected CD4+ T-cells. Here, we will review the role that viral orf-I protein products play in altering intracellular signaling, protein expression and cell-cell communication in order to escape immune recognition and promote T-cell proliferation. We will also review studies of orf-I mutations found in infected patients and their potential impact on viral load, transmission and persistence. Finally, we will compare the orf-I gene in HTLV-1 subtypes as well as related STLV-1.
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Affiliation(s)
- Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Veronica Galli
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ramona Moles
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - David Yurick
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia
| | - Georges Khoury
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia
| | - Damian F J Purcell
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Cynthia A Pise-Masison
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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13
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Georgieva ER. Non-Structural Proteins from Human T-cell Leukemia Virus Type 1 in Cellular Membranes-Mechanisms for Viral Survivability and Proliferation. Int J Mol Sci 2018; 19:ijms19113508. [PMID: 30413005 PMCID: PMC6274929 DOI: 10.3390/ijms19113508] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 12/27/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of illnesses, such as adult T-cell leukemia/lymphoma, myelopathy/tropical spastic paraparesis (a neurodegenerative disorder), and other diseases. Therefore, HTLV-1 infection is a serious public health concern. Currently, diseases caused by HTLV-1 cannot be prevented or cured. Hence, there is a pressing need to comprehensively understand the mechanisms of HTLV-1 infection and intervention in host cell physiology. HTLV-1-encoded non-structural proteins that reside and function in the cellular membranes are of particular interest, because they alter cellular components, signaling pathways, and transcriptional mechanisms. Summarized herein is the current knowledge about the functions of the membrane-associated p8I, p12I, and p13II regulatory non-structural proteins. p12I resides in endomembranes and interacts with host proteins on the pathways of signal transduction, thus preventing immune responses to the virus. p8I is a proteolytic product of p12I residing in the plasma membrane, where it contributes to T-cell deactivation and participates in cellular conduits, enhancing virus transmission. p13II associates with the inner mitochondrial membrane, where it is proposed to function as a potassium channel. Potassium influx through p13II in the matrix causes membrane depolarization and triggers processes that lead to either T-cell activation or cell death through apoptosis.
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Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
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14
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Donhauser N, Heym S, Thoma-Kress AK. Quantitating the Transfer of the HTLV-1 p8 Protein Between T-Cells by Flow Cytometry. Front Microbiol 2018; 9:400. [PMID: 29563906 PMCID: PMC5850991 DOI: 10.3389/fmicb.2018.00400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 02/21/2018] [Indexed: 01/01/2023] Open
Abstract
The Human T-cell leukemia virus type 1 (HTLV-1)-encoded accessory protein p8 is cleaved from the precursor protein p12 encoded by the HTLV-1 open reading frame I. Both p12 and p8 are thought to contribute to efficient viral persistence. Mechanistically, p8 induces T-cell conjugates and cellular conduits. The latter are considered to facilitate transfer of p8 to target cells and virus transmission. Transfer of p8 between p8-expressing T-cells and recipient cells has been analyzed by immunofluorescence and live imaging. However, automatic quantitation of p8-transfer between cells has not been studied yet. Here we developed a novel method allowing time saving quantitation of p8 transfer between cells by flow cytometry. After establishing a protocol for the detection of intracellular p8 by flow cytometry and validation of p8 protein expression by western blot and immunofluorescence, we set up a co-culture assay between p8-expressing donor Jurkat T-cells and recipient Jurkat T-cells that had been prestained with a well-retained live cell dye. Upon quantitating the amount of p8 positive recipient cells with regard to the percentage of p8 expressing donor cells, time course experiments confirmed that p8 is rapidly transferred between Jurkat T-cells. We found that p8 enters approximately 5% of recipient T-cells immediately upon co-culture for 5 min. Prolonged co-culture for up to 24 h revealed an increase of relative p8 transfer to approximately 23% of the recipient cells. Immunofluorescence analysis of co-culture experiments and manual quantitation of p8 expression in fluorescence images confirmed the validity of the flow cytometry based assay. Application of the new assay revealed that manipulation of actin polymerization significantly decreased p8 transfer between Jurkat T-cells suggesting an important role of actin dynamics contributing to p8 transfer. Further, transfer of p8 to co-cultured T-cells varies between different donor cell types since p8 transfer could hardly been detected in co-cultures of 293T donor cells with Jurkat acceptor cells. In summary, our novel assay allows automatic and rapid quantitation of p8 transfer to target cells and might thus contribute to a better understanding of cellular processes and dynamics regulating p8 transfer and HTLV-1 transmission.
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Affiliation(s)
- Norbert Donhauser
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stefanie Heym
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andrea K Thoma-Kress
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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15
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Rosadas C, Vicente ACP, Zanella L, Cabral-Castro MJ, Peralta JM, Puccioni-Sohler M. First report of HTLV-1 truncated p12 protein in Brazil. Virulence 2016; 8:1445-1449. [PMID: 27960650 DOI: 10.1080/21505594.2016.1267895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Carolina Rosadas
- a Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro , Brazil
| | - Ana C P Vicente
- b Laboratory of Molecular Genetics of Microorganisms, Fundação Oswaldo Cruz (IOC - FIOCRUZ) , Rio de Janeiro , Brazil
| | - Louise Zanella
- b Laboratory of Molecular Genetics of Microorganisms, Fundação Oswaldo Cruz (IOC - FIOCRUZ) , Rio de Janeiro , Brazil
| | | | - José M Peralta
- a Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro , Brazil
| | - Marzia Puccioni-Sohler
- a Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro , Brazil.,c Universidade Federal do Estado do Rio de Janeiro (UNIRIO) , Rio de Janeiro , Brazil
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16
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HTLV-1 ORF-I Encoded Proteins and the Regulation of Host Immune Response: Viral Induced Dysregulation of Intracellular Signaling. J Immunol Res 2015; 2015:498054. [PMID: 26557721 PMCID: PMC4628651 DOI: 10.1155/2015/498054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/22/2015] [Accepted: 08/31/2015] [Indexed: 01/02/2023] Open
Abstract
The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with both proliferative and inflammatory disorders. This virus causes a persistent infection, mainly in CD4+ T lymphocyte. The ability to persist in the host is associated with the virus capacity to evade the immune response and to induce infected T-cell proliferation, once the HTLV-1 maintains the infection mainly by clonal expansion of infected cells. There are several evidences that ORF-I encoded proteins, such as p12 and p8, play an important role in this context. The present study will review the molecular mechanisms that HTLV-1 ORF-I encoded proteins have to induce dysregulation of intracellular signaling, in order to escape from immune response and to increase the infected T-cell proliferation rate. The work will also address the impact of ORF-I mutations on the human
host and perspectives in this study field.
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17
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Pise-Masison CA, de Castro-Amarante MF, Enose-Akahata Y, Buchmann RC, Fenizia C, Washington Parks R, Edwards D, Fiocchi M, Alcantara LC, Bialuk I, Graham J, Walser JC, McKinnon K, Galvão-Castro B, Gessain A, Venzon D, Jacobson S, Franchini G. Co-dependence of HTLV-1 p12 and p8 functions in virus persistence. PLoS Pathog 2014; 10:e1004454. [PMID: 25375128 PMCID: PMC4223054 DOI: 10.1371/journal.ppat.1004454] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 09/08/2014] [Indexed: 11/19/2022] Open
Abstract
HTLV-1 orf-I is linked to immune evasion, viral replication and persistence. Examining the orf-I sequence of 160 HTLV-1-infected individuals; we found polymorphism of orf-I that alters the relative amounts of p12 and its cleavage product p8. Three groups were identified on the basis of p12 and p8 expression: predominantly p12, predominantly p8 and balanced expression of p12 and p8. We found a significant association between balanced expression of p12 and p8 with high viral DNA loads, a correlate of disease development. To determine the individual roles of p12 and p8 in viral persistence, we constructed infectious molecular clones expressing p12 and p8 (D26), predominantly p12 (G29S) or predominantly p8 (N26). As we previously showed, cells expressing N26 had a higher level of virus transmission in vitro. However, when inoculated into Rhesus macaques, cells producing N26 virus caused only a partial seroconversion in 3 of 4 animals and only 1 of those animals was HTLV-1 DNA positive by PCR. None of the animals exposed to G29S virus seroconverted or had detectable viral DNA. In contrast, 3 of 4 animals exposed to D26 virus seroconverted and were HTLV-1 positive by PCR. In vitro studies in THP-1 cells suggested that expression of p8 was sufficient for productive infection of monocytes. Since orf-I plays a role in T-cell activation and recognition; we compared the CTL response elicited by CD4+ T-cells infected with the different HTLV-1 clones. Although supernatant p19 levels and viral DNA loads for all four infected lines were similar, a significant difference in Tax-specific HLA.A2-restricted killing was observed. Cells infected with Orf-I-knockout virus (12KO), G29S or N26 were killed by CTLs, whereas cells infected with D26 virus were resistant to CTL killing. These results indicate that efficient viral persistence and spread require the combined functions of p12 and p8.
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Affiliation(s)
- Cynthia A. Pise-Masison
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | | | - Yoshimi Enose-Akahata
- Viral Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - R. Cody Buchmann
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Claudio Fenizia
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Robyn Washington Parks
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Dustin Edwards
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Martina Fiocchi
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | | | - Izabela Bialuk
- Department of General and Experimental Pathology, Medical University in Białystok, Białystok, Poland
| | - Jhanelle Graham
- Viral Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Jean-Claude Walser
- Evolutionary Biology, Genetic Diversity Centre, University of Basel, Basel, Switzerland
| | - Katherine McKinnon
- Vaccine Branch Flow Cytometry Core Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Antoine Gessain
- Unité d'Epidémiologie et Physiopathologie des Virus Oncogènes, Département de Virologie, Batiment Lwoff, Institut Pasteur, Paris, France
| | - David Venzon
- Biostatistics and Data Management Section, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Steven Jacobson
- Viral Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, Maryland, United States of America
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18
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Discovery and characterization of auxiliary proteins encoded by type 3 simian T-cell lymphotropic viruses. J Virol 2014; 89:931-51. [PMID: 25355890 DOI: 10.1128/jvi.02150-14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 encode auxiliary proteins that play important roles in viral replication, viral latency, and immune escape. The presence of auxiliary protein-encoding open reading frames (ORFs) in HTLV-3, the latest HTLV to be discovered, is unknown. Simian T-cell lymphotropic virus type 3 (STLV-3) is almost identical to HTLV-3. Given the lack of HTLV-3-infected cell lines, we took advantage of STLV-3-infected cells and of an STLV-3 molecular clone to search for the presence of auxiliary transcripts. Using reverse transcriptase PCR (RT-PCR), we first uncovered the presence of three unknown viral mRNAs encoding putative proteins of 5, 8, and 9 kDa and confirmed the presence of the previously reported RorfII transcript. The existence of these viral mRNAs was confirmed by using splice site-specific RT-PCR with ex vivo samples. We showed that p5 is distributed throughout the cell and does not colocalize with a specific organelle. The p9 localization is similar to that of HTLV-1 p12 and induced a strong decrease in the calreticulin signal, similarly to HTLV-1 p12. Although p8, RorfII, and Rex-3 share an N-terminal sequence that is predicted to contain a nucleolar localization signal (NoLS), only p8 is found in the nucleolus. The p8 location in the nucleolus is linked to a bipartite NoLS. p8 and, to a lesser extent, p9 repressed viral expression but did not alter Rex-3-dependent mRNA export. Using a transformation assay, we finally showed that none of the STLV-3 auxiliary proteins had the ability to induce colony formation, while both Tax-3 and antisense protein of HTLV-3 (APH-3) promoted cellular transformation. Altogether, these results complete the characterization of the newly described primate T-lymphotropic virus type 3 (PTLV-3). IMPORTANCE Together with their simian counterparts, HTLVs form the primate T-lymphotropic viruses. HTLVs arose from interspecies transmission between nonhuman primates and humans. HTLV-1 and HTLV-2 encode auxiliary proteins that play important roles in viral replication, viral latency, and immune escape. The presence of ORFs encoding auxiliary proteins in HTLV-3 or STLV-3 genomes was unknown. Using in silico analyses, ex vivo samples, or in vitro experiments, we have uncovered the presence of 3 previously unknown viral mRNAs encoding putative proteins and confirmed the presence of a previously reported viral transcript. We characterized the intracellular localization of the four proteins. We showed that two of these proteins repress viral expression but that none of them have the ability to induce colony formation. However, both Tax and the antisense protein APH-3 promote cell transformation. Our results allowed us to characterize 4 new retroviral proteins for the first time.
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Ciminale V, Rende F, Bertazzoni U, Romanelli MG. HTLV-1 and HTLV-2: highly similar viruses with distinct oncogenic properties. Front Microbiol 2014; 5:398. [PMID: 25120538 PMCID: PMC4114287 DOI: 10.3389/fmicb.2014.00398] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/15/2014] [Indexed: 12/29/2022] Open
Abstract
HTLV-1 and HTLV-2 share broad similarities in their overall genetic organization and expression pattern, but they differ substantially in their pathogenic properties. This review outlines distinctive features of HTLV-1 and HTLV-2 that might provide clues to explain their distinct clinical outcomes. Differences in the kinetics of viral mRNA expression, functional properties of the regulatory and accessory proteins, and interactions with cellular factors and signal transduction pathways are discussed.
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Affiliation(s)
- Vincenzo Ciminale
- Department of Surgery, Oncology and Gastroenterology, University of Padua Padua, Italy
| | - Francesca Rende
- Department of Surgery, Oncology and Gastroenterology, University of Padua Padua, Italy
| | - Umberto Bertazzoni
- Department of Life and Reproduction Sciences, University of Verona Verona, Italy
| | - Maria G Romanelli
- Department of Life and Reproduction Sciences, University of Verona Verona, Italy
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20
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McGill NK, Vyas J, Shimauchi T, Tokura Y, Piguet V. HTLV-1-associated infective dermatitis: updates on the pathogenesis. Exp Dermatol 2012; 21:815-21. [DOI: 10.1111/exd.12007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2012] [Indexed: 12/12/2022]
Affiliation(s)
- Neilia-Kay McGill
- Department of Dermatology and Wound Healing; Institute of Infection and Immunity; Cardiff University; Cardiff, UK
| | - Jui Vyas
- Department of Dermatology and Wound Healing; Institute of Infection and Immunity; Cardiff University; Cardiff, UK
| | - Takatoshi Shimauchi
- Department of Dermatology; Hamamatsu University School of Medicine; Hamamatsu; Japan
| | - Yoshiki Tokura
- Department of Dermatology; Hamamatsu University School of Medicine; Hamamatsu; Japan
| | - Vincent Piguet
- Department of Dermatology and Wound Healing; Institute of Infection and Immunity; Cardiff University; Cardiff, UK
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21
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Lairmore MD, Haines R, Anupam R. Mechanisms of human T-lymphotropic virus type 1 transmission and disease. Curr Opin Virol 2012; 2:474-81. [PMID: 22819021 DOI: 10.1016/j.coviro.2012.06.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 10/28/2022]
Abstract
Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15-20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3-5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma, or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis. The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as p30, p12, p13 and the antisense-encoded HTLV-1 basic leucine zipper factor (HBZ). While progress has been made in knowledge of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full-length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.
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Affiliation(s)
- Michael D Lairmore
- University of California-Davis, School of Veterinary Medicine, Davis, CA 95616, United States.
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Williamson CD, DeBiasi RL, Colberg-Poley AM. Viral product trafficking to mitochondria, mechanisms and roles in pathogenesis. Infect Disord Drug Targets 2012; 12:18-37. [PMID: 22034933 PMCID: PMC4435936 DOI: 10.2174/187152612798994948] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/21/2011] [Accepted: 05/02/2011] [Indexed: 05/31/2023]
Abstract
A wide variety of viruses cause significant morbidity and mortality in humans. However, targeted antiviral therapies have been developed for only a subset of these viruses, with the majority of currently licensed antiviral drugs targeting viral entry, replication or exit steps during the viral life cycle. Due to increasing emergence of antiviral drug resistant viruses, the isolation of multiple viral subtypes, and toxicities of existing therapies, there remains an urgent need for the timely development of novel antiviral agents, including those targeting host factors essential for viral replication. This review summarizes viral products that target mitochondria and their effects on common mitochondria regulated pathways. These viral products and the mitochondrial pathways affected by them provide potential novel targets for the rational design of antiviral drugs. Viral products alter oxidative balance, mitochondrial permeability transition pore, mitochondrial membrane potential, electron transport and energy production. Moreover, viruses may cause the Warburg Effect, in which metabolism is reprogrammed to aerobic glycolysis as the main source of energy. Finally, viral products affect proapoptotic and antiapoptotic signaling, as well as mitochondrial innate immune signaling. Because of their importance for the generation of metabolic intermediates and energy as well as cell survival, mitochondrial pathways are targeted by multiple independent viral products. Structural modifications of existing drugs targeted to mitochondrial pathways may lead to the development of novel antiviral drugs with improved efficacy and reduced toxicity.
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Affiliation(s)
- Chad D. Williamson
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
| | - Roberta L. DeBiasi
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Division of Pediatric Infectious Diseases, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
| | - Anamaris M. Colberg-Poley
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
- Department of Biochemistry and Molecular Biology, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
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Comparison of the Genetic Organization, Expression Strategies and Oncogenic Potential of HTLV-1 and HTLV-2. LEUKEMIA RESEARCH AND TREATMENT 2011; 2012:876153. [PMID: 23213551 PMCID: PMC3504254 DOI: 10.1155/2012/876153] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 09/24/2011] [Indexed: 11/30/2022]
Abstract
Human T cell leukemia virus types 1 and 2 (HTLV-1 and HTLV-2) are genetically related complex retroviruses that are capable of immortalizing human T-cells in vitro and establish life-long persistent infections in vivo. In spite of these apparent similarities, HTLV-1 and HTLV-2 exhibit a significantly different pathogenic potential. HTLV-1 is recognized as the causative agent of adult T-cell leukemia/lymphoma (ATLL) and tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM). In contrast, HTLV-2 has not been causally linked to human malignancy, although it may increase the risk of developing inflammatory neuropathies and infectious diseases. The present paper is focused on the studies aimed at defining the viral genetic determinants of the pathobiology of HTLV-1 and HTLV-2 through a comparison of the expression strategies and functional properties of the different gene products of the two viruses.
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Cavallari I, Rende F, D'Agostino DM, Ciminale V. Converging strategies in expression of human complex retroviruses. Viruses 2011; 3:1395-414. [PMID: 21994786 PMCID: PMC3185809 DOI: 10.3390/v3081395] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 07/28/2011] [Accepted: 07/28/2011] [Indexed: 12/27/2022] Open
Abstract
The discovery of human retroviruses in the early 1980s revealed the existence of viral-encoded non-structural genes that were not evident in previously described animal retroviruses. Based on the absence or presence of these additional genes retroviruses were classified as ‘simple’ and ‘complex’, respectively. Expression of most of these extra genes is achieved through the generation of alternatively spliced mRNAs. The present review summarizes the genetic organization and expression strategies of human complex retroviruses and highlights the converging mechanisms controlling their life cycles.
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Affiliation(s)
- Ilaria Cavallari
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
| | - Francesca Rende
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
- Istituto Oncologico Veneto-IRCCS, I-35128 Padova, Italy
| | - Donna M. D'Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
| | - Vincenzo Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
- Istituto Oncologico Veneto-IRCCS, I-35128 Padova, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.:+39-049-821-5885; Fax: +39-049-807-2854
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25
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Lairmore MD, Anupam R, Bowden N, Haines R, Haynes RAH, Ratner L, Green PL. Molecular determinants of human T-lymphotropic virus type 1 transmission and spread. Viruses 2011; 3:1131-65. [PMID: 21994774 PMCID: PMC3185783 DOI: 10.3390/v3071131] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/01/2011] [Accepted: 07/02/2011] [Indexed: 01/23/2023] Open
Abstract
Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15 to 20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells, most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3 to 5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma (ATL), or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as, p30, p12, p13 and the antisense encoded HBZ. While progress has been made in the understanding of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.
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Affiliation(s)
- Michael D. Lairmore
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-614-292-9203; Fax: +1-614-292-6473
| | - Rajaneesh Anupam
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Nadine Bowden
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Robyn Haines
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Rashade A. H. Haynes
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Division of Biology and Biological Sciences, Washington University School of Medicine, Campus Box 8069, 660 S. Euclid Ave., St. Louis, MO 63110, USA; E-Mail: (L.R.)
| | - Patrick L. Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Orf-I and orf-II-encoded proteins in HTLV-1 infection and persistence. Viruses 2011; 3:861-85. [PMID: 21994758 PMCID: PMC3185781 DOI: 10.3390/v3060861] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 01/10/2023] Open
Abstract
The 3′ end of the human T-cell leukemia/lymphoma virus type-1 (HTLV-1) genome contains four overlapping open reading frames (ORF) that encode regulatory proteins. Here, we review current knowledge of HTLV-1 orf-I and orf-II protein products. Singly spliced mRNA from orf-I encodes p12, which can be proteolytically cleaved to generate p8, while differential splicing of mRNA from orf-II results in production of p13 and p30. These proteins have been demonstrated to modulate transcription, apoptosis, host cell activation and proliferation, virus infectivity and transmission, and host immune responses. Though these proteins are not essential for virus replication in vitro, p8, p12, p13, and p30 have an important role in the establishment and maintenance of HTLV-1 infection in vivo.
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27
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Human T Lymphotropic Virus Type 1 (HTLV-1): Molecular Biology and Oncogenesis. Viruses 2010; 2:2037-2077. [PMID: 21994719 PMCID: PMC3185741 DOI: 10.3390/v2092037] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/25/2010] [Accepted: 09/15/2010] [Indexed: 12/13/2022] Open
Abstract
Human T lymphotropic viruses (HTLVs) are complex deltaretroviruses that do not contain a proto-oncogene in their genome, yet are capable of transforming primary T lymphocytes both in vitro and in vivo. There are four known strains of HTLV including HTLV type 1 (HTLV-1), HTLV-2, HTLV-3 and HTLV-4. HTLV-1 is primarily associated with adult T cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-2 is rarely pathogenic and is sporadically associated with neurological disorders. There have been no diseases associated with HTLV-3 or HTLV-4 to date. Due to the difference in the disease manifestation between HTLV-1 and HTLV-2, a clear understanding of their individual pathobiologies and the role of various viral proteins in transformation should provide insights into better prognosis and prevention strategies. In this review, we aim to summarize the data accumulated so far in the transformation and pathogenesis of HTLV-1, focusing on the viral Tax and HBZ and citing appropriate comparisons to HTLV-2.
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28
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Van Prooyen N, Andresen V, Gold H, Bialuk I, Pise-Masison C, Franchini G. Hijacking the T-cell communication network by the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) p12 and p8 proteins. Mol Aspects Med 2010; 31:333-43. [PMID: 20673780 DOI: 10.1016/j.mam.2010.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 07/22/2010] [Accepted: 07/23/2010] [Indexed: 12/14/2022]
Abstract
The non-structural proteins encoded by the orf-I, II, III, and IV genes of the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) genome, are critical for the modulation of cellular gene expression and T-cell proliferation, the escape from cytotoxic T-cells and natural killer cells, and virus expression. In here, we review the main functions of the HTLV-1 orf-I products. The 12kDa product from orf-I (p12) is proteolytically cleaved within the endoplasmic reticulum (ER) to generate the 8kDa protein (p8). At the steady state, both proteins are expressed at similar levels in transfected T-cells. The p12 protein remains in the ER and cis-Golgi, whereas the p8 protein traffics to the cell surface and is recruited to the immunological synapse. The p12 and the p8 proteins have seemingly opposite effects on T-cells; the ER resident p12, modulates T-cell activation and proliferation, whereas p8 induces T-cell anergy. The p8 protein also increases the formation of cellular conduits, is transferred to neighboring T-cells, and increases virus transmission. The requirement for HTLV-1 infectivity of orf-I is demonstrated by the loss of virus infectivity in macaques exposed to an engineered virus, whereby expression of orf-I was ablated. Altogether the current knowledge demonstrates that the concerted activity of p8 and p12 is essential for the persistence of virus infected cells in the host.
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Affiliation(s)
- Nancy Van Prooyen
- Animal Models and Retroviral Vaccine Section, Vaccine Branch, National Cancer Institute, National Institute of Health, Bethesda, MD 20892-5065, USA
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29
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Requirement of the human T-cell leukemia virus p12 and p30 products for infectivity of human dendritic cells and macaques but not rabbits. Blood 2010; 116:3809-17. [PMID: 20647569 DOI: 10.1182/blood-2010-05-284141] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The identification of the genes necessary for human T-cell leukemia virus (HTLV-1) persistence in humans may provide targets for therapeutic approaches. We demonstrate that ablation of the HTLV-1 genes encoding p12, p30, or the HBZ protein, does not affect viral infectivity in rabbits and in this species, only the absence of HBZ is associated with a consistent reduction in virus levels. We observed reversion of the HTLV-1 mutants to the HTLV-1 wild-type genotype in none of the inoculated rabbits. In contrast, in macaques, the absence of HBZ was associated with reversion of the mutant virus to the wild-type genotype in 3 of the 4 animals within weeks from infection. Similarly, reversion to the wild type was observed in 2 of the 4 macaque inoculated with the p30 mutant. The 4 macaques exposed to the p12 knock remained seronegative, and only 2 animals were positive at a single time point for viral DNA in tissues. Interestingly, we found that the p12 and the p30 mutants were also severely impaired in their ability to replicate in human dendritic cells. These data suggest that infection of dendritic cells may be required for the establishment and maintenance of HTLV-1 infection in primate species.
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30
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Biasiotto R, Aguiari P, Rizzuto R, Pinton P, D'Agostino DM, Ciminale V. The p13 protein of human T cell leukemia virus type 1 (HTLV-1) modulates mitochondrial membrane potential and calcium uptake. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:945-51. [DOI: 10.1016/j.bbabio.2010.02.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 11/24/2022]
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31
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Galluzzi L, Kepp O, Morselli E, Vitale I, Senovilla L, Pinti M, Zitvogel L, Kroemer G. Viral strategies for the evasion of immunogenic cell death. J Intern Med 2010; 267:526-42. [PMID: 20433579 DOI: 10.1111/j.1365-2796.2010.02223.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Viral strategies for the evasion of immunogenic cell death (Symposium). J Intern Med 2010; 267: 526-542. Driven by co-evolutionary forces, viruses have refined a wide arsenal of strategies to interfere with the host defences. On one hand, viruses can block/retard programmed cell death in infected cells, thereby suppressing one of the most ancient mechanisms against viral dissemination. On the other hand, multiple viral factors can efficiently trigger the death of infected cells and uninfected cells from the immune system, which favours viral spreading and prevents/limits an active antiviral response, respectively. Moreover, several viruses are able to inhibit the molecular machinery that drives the translocation of calreticulin to the surface of dying cells. Thereby, viruses block the exposure of an engulfment signal that is required for the efficient uptake of dying cells by dendritic cells and for the induction of the immune response. In this review, we discuss a variety of mechanisms by which viruses interfere with the cell death machinery and, in particular, by which they subvert immunogenic cell death.
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32
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Silic-Benussi M, Biasiotto R, Andresen V, Franchini G, D'Agostino DM, Ciminale V. HTLV-1 p13, a small protein with a busy agenda. Mol Aspects Med 2010; 31:350-8. [PMID: 20332002 DOI: 10.1016/j.mam.2010.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 01/16/2023]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) infection is characterized by life-long persistence of the virus in the host. While most infected individuals remain asymptomatic, 3-5% will eventually develop adult T-cell leukemia/lymphoma (ATLL) or tropical spastic paraparesis/HTLV-associated myelopathy (TSP/HAM) after a clinical latency that can span years (TSP/HAM) to decades (ATLL). The major oncogenic determinant among HTLV-1 proteins is the Tax transactivator, which influences the expression and function of a great number of cellular proteins, drives cell proliferation, reduces cell death, and induces genetic instability. The present review is focused on the current knowledge of p13, an HTLV-1 accessory protein targeted to the inner mitochondrial membrane and, under certain conditions, to the nucleus. In mitochondria, p13 produces an inward K+current that results in an increased production of ROS by mitochondria. These effects are linked to the protein's effects on cell turnover which include activation of primary T-cells and reduced proliferation/sensitization to death of tumor cells. Recent findings suggest that in the presence of Tax, p13 is subjected to ubiquitylation and partly targeted to the nucleus. Nuclear p13 binds Tax and inhibits its transcriptional activity. These findings suggest that the protein might exert distinct functions depending on its intracellular localization and influence both the turnover of infected cells and the balance between viral latency and productive infection.
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Affiliation(s)
- Micol Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padova, Padova, Italy
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33
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Bagossi P, Bander P, Bozóki B, Tözsér J. Discovery and significance of new human T-lymphotropic viruses: HTLV-3 and HTLV-4. Expert Rev Anti Infect Ther 2010; 7:1235-49. [PMID: 19968515 DOI: 10.1586/eri.09.97] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) were discovered approximately 30 years ago and they are associated with various lymphoproliferative and neurological diseases. The estimated number of infected people is 10-20 million worldwide. In 2005, two new HTLV-1/HTLV-2-related viruses were detected, HTLV-3 and HTLV-4, from the same geographical area of Africa. In the last 4 years, their complete genomic sequences were determined and some of their characteristic features were studied in detail. These newly discovered retroviruses alongside their human (HTLV-1 and -2) and animal relatives (simian T-lymphotropic virus type 1-3) are reviewed. The potential risks associated with these viruses and the potential antiretroviral therapies are also discussed.
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Affiliation(s)
- Péter Bagossi
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, Hungary.
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34
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Jheng JR, Lau KS, Tang WF, Wu MS, Horng JT. Endoplasmic reticulum stress is induced and modulated by enterovirus 71. Cell Microbiol 2010; 12:796-813. [PMID: 20070307 DOI: 10.1111/j.1462-5822.2010.01434.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Picornavirus infection alters the endoplasmic reticulum (ER) membrane but it is unclear whether this induces ER stress. Infection of rhabdomyosarcoma cells with enterovirus 71 (EV71), a picornavirus, caused overexpression of the ER-resident chaperone proteins, BiP and calreticulin, and phosphorylation of eIF2alpha, but infection with UV-inactivated virus did not, indicating that ER stress was induced by viral replication and not by viral attachment or entry. Silencing (si)RNA knockdown demonstrated that phosphorylation of eIF2alpha was dependent on PKR: eIF2alpha phosphorylation was reduced by siPKR but not by siPERK. We provided evidence showing that PERK is upstream of PKR and is thus able to negatively regulate the PKR-eIF2alpha pathway. Pulse-chase experiments revealed that EV71 infection inhibited translation and activation of ATF6. Expression of BiP at the protein level was activated by a virus-dependent, ATF6-independent mechanism. EV71 upregulated XBP1 mRNA level, but neither IRE1-mediated XBP1 splicing nor its active spliced protein was detected, and its downstream gene, EDEM, was not activated. Epigenetic BiP overexpression alleviated EV71-induced ER stress and reduced viral protein expression and replication. Our results suggest that EV71 infection induces ER stress but modifies the outcome to assist viral replication.
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Affiliation(s)
- Jia-Rong Jheng
- Department of Biochemistry, Chang Gung University, Kweishan, Taoyuan, Taiwan
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35
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Murray L, Luke GA, Ryan MD, Wileman T, Knox C. Amino acid substitutions within the 2C coding sequence of Theiler's Murine Encephalomyelitis virus alter virus growth and affect protein distribution. Virus Res 2009; 144:74-82. [PMID: 19728403 DOI: 10.1016/j.virusres.2009.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Theiler's murine encephalomyelitis virus (TMEV) was used to investigate the distribution of P2 proteins in host cells and examine the effect of amino acid substitutions in conserved residues of the 2C protein on virus growth. The distribution of viral proteins 2B, 2C and 2BC with marker proteins of the endoplasmic reticulum (ER) and/or Golgi suggest an association with membranes of the secretory pathway. Similar results were obtained for truncated 2C and 2BC proteins with C-terminal deletions suggesting that the N-terminal region of the 2C protein is important in dictating distribution patterns. The significance of the high degree of conservation of this 2C region throughout the Picornaviridae was investigated by substituting conserved amino acid residues for alanine to create six mutant strains. Substitution mutations E(8)A, W(18)A and W(29)A abolished the ability of the virus to induce cytopathic effect (CPE) in BHK-21 cells. K(14)A, R(4)A and I(23)A delayed the onset and progression of CPE compared to the wild-type (WT) virus, and decreased virus yield. Immunofluorescence analysis of cells transiently expressing mutant 2C proteins revealed that the distribution of 2C was affected by substituting K(14), W(18) and I(23) for alanine indicating that specific conserved residues in 2C dictate protein distribution and virus growth.
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Affiliation(s)
- Lindsay Murray
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, Eastern Cape, South Africa
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36
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Zhou Y, Frey TK, Yang JJ. Viral calciomics: interplays between Ca2+ and virus. Cell Calcium 2009; 46:1-17. [PMID: 19535138 PMCID: PMC3449087 DOI: 10.1016/j.ceca.2009.05.005] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 12/23/2022]
Abstract
Ca2+ is one of the most universal and versatile signaling molecules and is involved in almost every aspect of cellular processes. Viruses are adept at utilizing the universal Ca2+ signal to create a tailored cellular environment that meets their own demands. This review summarizes most of the known mechanisms by which viruses perturb Ca2+ homeostasis and utilize Ca2+ and cellular Ca2+-binding proteins to their benefit in their replication cycles. Ca2+ plays important roles in virion structure formation, virus entry, viral gene expression, posttranslational processing of viral proteins and virion maturation and release. As part of the review, we introduce an algorithm to identify linear “EF-hand” Ca2+-binding motifs which resulted in the prediction of a total of 93 previously unrecognized Ca2+-binding motifs in virus proteins. Many of these proteins are nonstructural proteins, a class of proteins among which Ca2+ interactions had not been formerly appreciated. The presence of linear Ca2+-binding motifs in viral proteins enlarges the spectrum of Ca2+–virus interplay and expands the total scenario of viral calciomics.
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Affiliation(s)
- Yubin Zhou
- Department of Chemistry, Georgia State University, 50 Decatur St., Atlanta, GA 30303 USA
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37
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Journo C, Douceron E, Mahieux R. HTLV gene regulation: because size matters, transcription is not enough. Future Microbiol 2009; 4:425-40. [PMID: 19416012 DOI: 10.2217/fmb.09.13] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Despite being discovered in animals in the early 20th century, the scientific interest in retroviruses was boosted with the discovery of human retroviruses (human T-leukemia/lymphoma virus [HTLV] and HIV), which are responsible for significant morbidity and mortality. HTLV was identified more than 25 years ago as the etiological agent of adult T-cell leukemia/lymphoma. It was then shown to be a complex retrovirus, given that it not only encodes the characteristic retroviral Gag, Pol and Env proteins, but also regulatory and accessory proteins. Since the first studies documenting the role of these proteins in viral expression, the picture has become increasingly more complex. Indeed, owing to the limited size of its genome that contains overlapping open-reading frames, HTLV has evolved unique ways to regulate its expression. Retroviral expression was originally thought to be mainly controlled through the regulation of transcription from the 5 long-terminal repeats, but we now know that the 3 long-terminal repeats also serve as promoters. Regulation of splicing and mRNA export, and post-translational modifications of viral protein also play a major role. This review discusses the latest insights gained into the field of HTLV gene expression.
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Affiliation(s)
- Chloé Journo
- Equipe Oncogenèse Rétrovirale, INSERM-U758 Virologie Humaine, 69364 Lyon Cedex 07, France
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Kinetic analysis of human T-cell leukemia virus type 1 gene expression in cell culture and infected animals. J Virol 2009; 83:3788-97. [PMID: 19193802 DOI: 10.1128/jvi.02315-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) infection causes adult T-cell leukemia and is associated with a variety of lymphocyte-mediated disorders. It has been hypothesized that a highly regulated pattern of HTLV-1 gene expression is critical for virus survival and disease pathogenesis. In this study, real-time reverse transcriptase PCR was used to determine the kinetics of viral gene expression in cells transiently transfected with an HTLV-1 proviral plasmid, in newly infected human peripheral blood mononuclear cells (PBMCs), and in PBMCs from newly infected rabbits. The HTLV-1 gene expression profiles in transiently transfected and infected cells were similar; over time, all transcripts increased and then maintained stable levels. gag/pol, tax/rex, and env mRNA were detected first and at the highest levels, whereas the expression levels of the accessory genes, including the antisense Hbz, were significantly lower than the tax/rex levels (ranging from 1 to 4 logs depending on the specific mRNA). In infected rabbits, tax/rex and gag/pol mRNA levels peaked early after inoculation and progressively decreased, which correlated inversely with the proviral load and host antibody response against viral proteins. Interestingly, Hbz mRNA was detectable at 1 week postinfection and increased and stabilized. The expression levels of all other HTLV-1 genes in infected rabbit PBMCs were at or below our limit of detection. This analysis provides insight into viral gene expression under various in vitro and in vivo experimental conditions. Our in vivo data indicate that in infected rabbits, Hbz mRNA expression over time directly correlates with the proviral load, which provides the first evidence linking Hbz expression to proviral load and the survival of the virus-infected cell in the host.
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In vivo genetic mutations define predominant functions of the human T-cell leukemia/lymphoma virus p12I protein. Blood 2008; 113:3726-34. [PMID: 18791162 DOI: 10.1182/blood-2008-04-146928] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human T-cell leukemia/lymphoma virus type 1 (HTLV-1) ORF-I encodes a 99-amino acid hydrophobic membrane protein, p12(I), that affects receptors in different cellular compartments. We report here that proteolytic cleavage dictates different cellular localization and functions of p12(I). The removal of a noncanonical endoplasmic reticulum (ER) retention/retrieval signal within the amino terminus of p12(I) is necessary for trafficking to the Golgi apparatus and generation of a completely cleaved 8-kDa protein. The 8-kDa protein in turn traffics to the cell surface, is recruited to the immunologic synapse following T-cell receptor (TCR) ligation, and down-regulates TCR proximal signaling. The uncleaved 12-kDa form of p12(I) resides in the ER and interacts with the beta and gamma(c) chains of the interleukin-2 receptor (IL-2R), the heavy chain of the major histocompatibility complex (MHC) class I, as well as calreticulin and calnexin. Genetic analysis of ORF-I from ex vivo samples of HTLV-1-infected patients reveals predominant amino acid substitutions within ORF-I that affect proteolytic cleavage, suggesting that ER-associated functions of p12(I) may contribute to the survival and proliferation of the infected T cells in the host.
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Laybourn P. The ups and downs of Tax and histones in adult T-cell leukemogenesis. Future Oncol 2008; 4:311-7. [PMID: 18518755 DOI: 10.2217/14796694.4.3.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Bogenberger JM, Laybourn PJ. Human T Lymphotropic Virus Type 1 protein Tax reduces histone levels. Retrovirology 2008; 5:9. [PMID: 18237376 PMCID: PMC2276518 DOI: 10.1186/1742-4690-5-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 01/31/2008] [Indexed: 12/21/2022] Open
Abstract
Background Human T-Lymphotropic Virus Type-1 (HTLV-1) is an oncogenic retrovirus that causes adult T-cell leukemia/lymphoma (ATLL). The virally encoded Tax protein is thought to be necessary and sufficient for T-cell leukemogenesis. Tax promotes inappropriate cellular proliferation, represses multiple DNA repair mechanisms, deregulates cell cycle checkpoints, and induces genomic instability. All of these Tax effects are thought to cooperate in the development of ATLL. Results In this study, we demonstrate that histone protein levels are reduced in HTLV-1 infected T-cell lines (HuT102, SLB-1 and C81) relative to uninfected T-cell lines (CEM, Jurkat and Molt4), while the relative amount of DNA per haploid complement is unaffected. In addition, we show that replication-dependent core and linker histone transcript levels are reduced in HTLV-1 infected T-cell lines. Furthermore, we show that Tax expression in Jurkat cells is sufficient for reduction of replication-dependent histone transcript levels. Conclusion These results demonstrate that Tax disrupts the proper regulation of replication-dependent histone gene expression. Further, our findings suggest that HTLV-1 infection uncouples replication-dependent histone gene expression and DNA replication, allowing the depletion of histone proteins with cell division. Histone proteins are involved in the regulation of all metabolic processes involving DNA including transcription, replication, repair and recombination. This study provides a previously unidentified mechanism by which Tax may directly induce chromosomal instability and deregulate gene expression through reduced histone levels.
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Affiliation(s)
- James M Bogenberger
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA.
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Yasunaga JI, Matsuoka M. Leukaemogenic mechanism of human T-cell leukaemia virus type I. Rev Med Virol 2007; 17:301-11. [PMID: 17621367 DOI: 10.1002/rmv.548] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Adult T-cell leukaemia (ATL) is a neoplastic disease derived from CD4(+) T-lymphocytes and etiologically associated with human T-cell leukaemia virus type I (HTLV-I). In addition to structural genes, HTLV-I encodes regulatory and accessory genes in the pX region. Among them, Tax is thought to play a central role in leukaemogenesis through its potent transforming activity. However, since Tax is a major target of the host immune system, its expression is often lost in ATL cells, indicating Tax is dispensable in the last phase of leukaemogenesis. The HTLV-I bZIP factor (HBZ), encoded on the HTLV-I minus strand, was recently shown to be expressed in all ATL cells, and to support growth of human T-cell lines. These findings suggest that HBZ is critical to ATL onset. In addition to viral factors and genetic and epigenetic changes in cellular genes, the host immune status and genetic background also function in leukaemogenesis.
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Affiliation(s)
- Jun-ichirou Yasunaga
- Laboratory of Virus Immunology, Institute for Virus Research, Kyoto University, Kyoto, Japan.
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Fukumoto R, Dundr M, Nicot C, Adams A, Valeri VW, Samelson LE, Franchini G. Inhibition of T-cell receptor signal transduction and viral expression by the linker for activation of T cells-interacting p12(I) protein of human T-cell leukemia/lymphoma virus type 1. J Virol 2007; 81:9088-99. [PMID: 17582004 PMCID: PMC1951423 DOI: 10.1128/jvi.02703-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The p12(I) protein of human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is a small oncoprotein that increases calcium release following protein kinase C activation by phorbol myristate acetate, and importantly, this effect is linker for activation of T cells (LAT) independent. Here, we demonstrate that p12(I) inhibits the phosphorylation of LAT, Vav, and phospholipase C-gamma 1 and decreases NFAT (nuclear factor of activated T cells) activation upon engagement of the T-cell receptor (TCR) with anti-CD3 antibody. Furthermore, we demonstrate that p12(I) localizes to membrane lipid rafts and, upon engagement of the TCR, relocalizes to the interface between T cells and antigen-presenting cells, defined as the immunological synapse. A p12(I) knockout molecular clone of HTLV-1 expresses more virus upon antigen stimulation than the isogenic wild type, suggesting that, by decreasing T-cell responsiveness, p12(I) curtails viral expression. Thus, p12(I) has contrasting effects on TCR signaling: it down-regulates TCR in a LAT-dependent manner on one hand, and on the other, it increases calcium release in a LAT-independent manner. The negative regulation of T-cell activation by p12(I) may have evolved to minimize immune recognition of infected CD4(+) T cells, to impair the function of infected cytotoxic CD8(+) T cells, and to favor viral persistence in the infected host.
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Affiliation(s)
- Risaku Fukumoto
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH, Bethesda, MD 20892-5065, USA
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Jin Z, Tietjen I, Bu L, Liu-Yesucevitz L, Gaur SK, Walsh CA, Piao X. Disease-associated mutations affect GPR56 protein trafficking and cell surface expression. Hum Mol Genet 2007; 16:1972-85. [PMID: 17576745 DOI: 10.1093/hmg/ddm144] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bilateral frontoparietal polymicrogyria (BFPP) is a congenital brain malformation resulting in irregularities on the surface of the cortex, where normally convoluted gyri are replaced by numerous (poly) and noticeably smaller (micro) gyri. Individuals with BFPP suffer from epilepsy, mental retardation, language impairment and motor developmental delay. Mutations in the gene-encoding G protein-coupled receptor 56 (GPR56) cause BFPP; however, it remains unclear how these mutations affect GPR56 function. Here, we examine the biochemical properties and protein trafficking of wild-type and mutant GPR56. We demonstrate that GPR56 protein undergoes two major modifications, GPS domain-mediated protein cleavage and N-glycosylation, and that the N-terminal fragment can be released from the cell surface. In contrast to the wild-type protein, disease-associated GPR56 missense mutations in the tip of the N-terminal domain (R38Q, R38W, Y88C and C91S) produce proteins with reduced intracellular trafficking and poor cell surface expression, whereas the two mutations in the GPS domain (C346S and W349S) produce proteins with dramatically impaired cleavage that fail to traffic beyond the endoplasmic reticulum. Cell-trafficking impairments are abrogated in part by pharmacological chaperones that can partially rescue mutant GPR56 cell surface expression. These data demonstrate that some BFPP-associated mutations in GPR56 impair trafficking of the mutant protein to the plasma membrane, thus providing insights into how BFPP-associated mutations affect GPR56 function.
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Affiliation(s)
- Zhaohui Jin
- Division of Newborn Medicine, Department of Medicine, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
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Yasunaga JI, Matsuoka M. [HTLV-I and leukemogenesis]. Uirusu 2007; 56:241-9. [PMID: 17446673 DOI: 10.2222/jsv.56.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Human T-cell leukemia virus type I (HTLV-I) is a causative virus of adult T-cell leukemia (ATL). ATL is a highly aggressive neoplastic disease of CD4 positive T lymphocyte, which is featured by the pleomorphic tumor cells with hypersegmented nuclei, called " flower cell". HTLV-I increases its copy number by clonal proliferation of the host cells, not by replication of the virus. Therefore, HTLV-I eventually induces ATL. Tax, encoded by HTLV-I pX region, has been recognized as a protein that plays a central role of the transformation of HTLV-I-infected cells by its pleiotropic actions. However, fresh ATL cells frequently lose Tax protein expression by several mechanisms. Recently, HBZ was identified in the complementary strand of HTLV-I and it is suggested that HBZ is a critical gene in leukemogenesis. Furthermore, there is a long latency period before onset of ATL, indicating the multistep mechanisms of leukemogenesis. Therefore, it is suggested that multiple factors, such as viral proteins, genetic and epigenetic changes of host genome, and immune status of the hosts, could be implicated in leukemogenesis of ATL.
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Affiliation(s)
- Jun-ichirou Yasunaga
- Laboratory of Human Tumor Viruses Department of Viral Oncology Institute for Virus Research, Kyoto University.
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Matsuoka M, Jeang KT. Human T-cell leukaemia virus type 1 (HTLV-1) infectivity and cellular transformation. Nat Rev Cancer 2007; 7:270-80. [PMID: 17384582 DOI: 10.1038/nrc2111] [Citation(s) in RCA: 606] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has been 30 years since a 'new' leukaemia termed adult T-cell leukaemia (ATL) was described in Japan, and more than 25 years since the isolation of the retrovirus, human T-cell leukaemia virus type 1 (HTLV-1), that causes this disease. We discuss HTLV-1 infectivity and how the HTLV-1 Tax oncoprotein initiates transformation by creating a cellular environment favouring aneuploidy and clastogenic DNA damage. We also explore the contribution of a newly discovered protein and RNA on the HTLV-1 minus strand, HTLV-1 basic leucine zipper factor (HBZ), to the maintenance of virus-induced leukaemia.
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Affiliation(s)
- Masao Matsuoka
- Laboratory of Virus Immunology, Institute for Virus Research, Kyoto University, Japan
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Miyazaki M, Yasunaga JI, Taniguchi Y, Tamiya S, Nakahata T, Matsuoka M. Preferential selection of human T-cell leukemia virus type 1 provirus lacking the 5' long terminal repeat during oncogenesis. J Virol 2007; 81:5714-23. [PMID: 17344291 PMCID: PMC1900290 DOI: 10.1128/jvi.02511-06] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In adult T-cell leukemia (ATL) cells, a defective human T-cell leukemia virus type 1 (HTLV-1) provirus lacking the 5' long terminal repeat (LTR), designated type 2 defective provirus, is frequently observed. To investigate the mechanism underlying the generation of the defective provirus, we sequenced HTLV-1 provirus integration sites from cases of ATL. In HTLV-1 proviruses retaining both LTRs, 6-bp repeat sequences were adjacent to the 5' and 3' LTRs. In 8 of 12 cases with type 2 defective provirus, 6-bp repeats were identified at both ends. In five of these cases, a short repeat was bound to CA dinucleotides of the pol and env genes at the 5' end, suggesting that these type 2 defective proviruses were formed before integration. In four cases lacking the 6-bp repeat, short (6- to 26-bp) deletions in the host genome were identified, indicating that these defective proviruses were generated after integration. Quantification indicated frequencies of type 2 defective provirus of less than 3.9% for two carriers, which are much lower than those seen for ATL cases (27.8%). In type 2 defective proviruses, the second exons of the tax, rex, and p30 genes were frequently deleted, leaving Tax unable to activate NF-kappaB and CREB pathways. The HTLV-1 bZIP factor gene, located on the minus strand, is expressed in ATL cells with this defective provirus, and its coding sequences are intact, suggesting its significance in oncogenesis.
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Affiliation(s)
- Maki Miyazaki
- Laboratory of Virus Immunology, Institute for Virus Research, Kyoto University, Shogoin Kawara-cho 53, Sakyo-ku, Kyoto 606-8507, Japan
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Li M, Green PL. Detection and quantitation of HTLV-1 and HTLV-2 mRNA species by real-time RT-PCR. J Virol Methods 2007; 142:159-68. [PMID: 17337070 PMCID: PMC2048902 DOI: 10.1016/j.jviromet.2007.01.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/18/2007] [Accepted: 01/26/2007] [Indexed: 11/17/2022]
Abstract
HTLV-1 and HTLV-2 are highly related delta-retroviruses that infect and transform T-lymphocytes, but have distinct pathogenic properties. HTLV replication and survival requires the expression of multiple gene products from an unspliced and a series of highly related alternatively spliced mRNA species. To date, the comparative levels of all known HTLV-1 and HTLV-2 viral mRNAs in different transformed cell lines and at different stages of virus infection have not been assessed. In this study, we compiled a series of oligonucleotide primer pairs and probes to quantify both HTLV-1 and HTLV-2 mRNA species using real-time RT-PCR. The optimized reaction for detection of each mRNA had amplification efficiency greater than 90% with a linear range spanning 25-2.5 x 10(7) copies. The R(2)'s of all standard curves were greater than 0.97. Quantitation of HTLV mRNAs between different cell lines showed variability (gag/pol>or=tax/rex>env>or=accessory proteins), but the overall levels of each mRNA relative to each other within a cell line were similar. These results provide a method to quantify all specific mRNAs from both HTLV-1 and HTLV-2, which can be used to evaluate further viral gene expression and correlate transcript levels to key stages of the virus life cycle and ultimately, pathogenesis.
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Affiliation(s)
- Min Li
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210
- Ohio State Biochemistry Graduate Program, The Ohio State University, Columbus, OH 43210
| | - Patrick L. Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
- Department of Molecular Virology Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, OH 43210
- Ohio State Biochemistry Graduate Program, The Ohio State University, Columbus, OH 43210
- * Corresponding Author: Patrick L. Green, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, Tel: (614)-688-4899, Fax: (614)-292-6473,
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Chami M, Oulès B, Paterlini-Bréchot P. Cytobiological consequences of calcium-signaling alterations induced by human viral proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1344-62. [PMID: 17059849 DOI: 10.1016/j.bbamcr.2006.09.025] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 09/13/2006] [Accepted: 09/15/2006] [Indexed: 01/25/2023]
Abstract
Since calcium-signaling regulates specific and fundamental cellular processes, it represents the ideal target of viral proteins, in order for the virus to control cellular functions and favour its persistence, multiplication and spread. A detailed analysis of reports focused on the impact of viral proteins on calcium-signaling has shown that virus-related elevations of cytosolic calcium levels allow increased viral protein expression (HIV-1, HSV-1/2), viral replication (HBx, enterovirus 2B, HTLV-1 p12(I), HHV-8, EBV), viral maturation (rotavirus), viral release (enterovirus 2B) and cell immortalization (EBV). Interestingly, virus-induced decreased cytosolic calcium levels have been found to be associated with inhibition of immune cells functions (HIV-1 Tat, HHV-8 K15, EBV LMP2A). Finally, several viral proteins are able to modulate intracellular calcium-signaling to control cell viability (HIV-1 Tat, HTLV-1 p13(II), HCV core, HBx, enterovirus 2B, HHV-8 K7). These data point out calcium-signaling as a key cellular target for viral infection and should stimulate further studies exploring new calcium-related therapeutic strategies.
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