1
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Hirons A, Yurick D, Jansz N, Ellenberg P, Franchini G, Einsiedel L, Khoury G, Purcell DFJ. High level of genomic divergence in orf-I p12 and hbz genes of HTLV-1 subtype-C in Central Australia. Retrovirology 2024; 21:14. [PMID: 39014486 PMCID: PMC11253349 DOI: 10.1186/s12977-024-00647-w] [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: 03/18/2024] [Accepted: 06/12/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND Human T cell lymphotropic virus type 1 (HTLV-1) infection remains a largely neglected public health problem, particularly in resource-poor areas with high burden of communicable and non-communicable diseases, such as some remote populations in Central Australia where an estimated 37% of adults are infected with HTLV-1. Most of our understanding of HTLV-1 infection comes from studies of the globally spread subtype-A (HTLV-1a), with few molecular studies reported with the Austral-Melanesian subtype-C (HTLV-1c) predominant in the Indo-Pacific and Oceania regions. RESULTS Using a primer walking strategy and direct sequencing, we constructed HTLV-1c genomic consensus sequences from 22 First Nations participants living with HTLV-1c in Central Australia. Phylogenetic and pairwise analysis of this subtype-C proviral gDNA showed higher levels of genomic divergence in comparison to previously published HTLV-1a genomes. While the overall genomic homology between subtypes was 92.5%, the lowest nucleotide and amino acid sequence identity occurred near the 3' end of the proviral genome coding regulatory genes, especially overlapping hbz (85.37%, 77.46%, respectively) and orf-I product p12 (82.00%, 70.30%, respectively). Strikingly, the HTLV-1c genomic consensus sequences uniformly showed a defective translation start codon for the immune regulatory proteins p12/p8 encoded by the HTLV-1A orf-I. Deletions in the proviral genome were detected in many subjects, particularly in the structural gag, pol and env genes. Similarly, using a droplet digital PCR assay measuring the copies of gag and tax per reference host genome, we quantitatively confirmed that provirus retains the tax gene region at higher levels than gag. CONCLUSIONS Our genomic analysis of HTLV-1c in Central Australia in conjunction with earlier Melanesian HTLV-1c sequences, elucidate substantial differences with respect to the globally spread HTLV-1a. Future studies should address the impact these genomic differences have on infection and the regionally distinctive frequency of associated pulmonary disease. Understanding the host and virus subtype factors which contribute to the differential morbidity observed, is crucial for the development of much needed therapeutics and vaccine strategies against this highly endemic infection in remote First Nations communities in Central Australia.
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Affiliation(s)
- Ashley Hirons
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
| | - David Yurick
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
- UCB Pharma, Smyrna, GA, USA
| | - Natasha Jansz
- Mater Research Institute-University of Queensland, TRI Building, Woolloongabba, QLD, Australia
| | - Paula Ellenberg
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
- Burnet Institute, Melbourne, VIC, Australia
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lloyd Einsiedel
- Department of Medicine, Alice Springs Hospital, Alice Springs, NT, Australia
| | - Georges Khoury
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
- Kite Pharma, Santa Monica, CA, USA
| | - Damian F J Purcell
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia.
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2
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Marino-Merlo F, Grelli S, Mastino A, Lai M, Ferrari P, Nicolini A, Pistello M, Macchi B. Human T-Cell Leukemia Virus Type 1 Oncogenesis between Active Expression and Latency: A Possible Source for the Development of Therapeutic Targets. Int J Mol Sci 2023; 24:14807. [PMID: 37834255 PMCID: PMC10572738 DOI: 10.3390/ijms241914807] [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: 08/13/2023] [Revised: 09/16/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) is the only known human oncogenic retrovirus. HTLV-1 can cause a type of cancer called adult T-cell leukemia/lymphoma (ATL). The virus is transmitted through the body fluids of infected individuals, primarily breast milk, blood, and semen. At least 5-10 million people in the world are infected with HTLV-1. In addition to ATL, HTLV-1 infection can also cause HTLV-I-associated myelopathy (HAM/TSP). ATL is characterized by a low viral expression and poor prognosis. The oncogenic mechanism triggered by HTLV-1 is extremely complex and the molecular pathways are not fully understood. However, viral regulatory proteins Tax and HTLV-1 bZIP factor (HBZ) have been shown to play key roles in the transformation of HTLV-1-infected T cells. Moreover, several studies have shown that the final fate of HTLV-1-infected transformed Tcell clones is the result of a complex interplay of HTLV-1 oncogenic protein expression with cellular transcription factors that subvert the cell cycle and disrupt regulated cell death, thereby exerting their transforming effects. This review provides updated information on the mechanisms underlying the transforming action of HTLV-1 and highlights potential therapeutic targets to combat ATL.
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Affiliation(s)
- Francesca Marino-Merlo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;
| | - Sandro Grelli
- Department of Experimental Medicine, University of Rome “Tor Vergata”, 00133 Rome, Italy;
| | - Antonio Mastino
- The Institute of Translational Pharmacology, CNR, 00133 Rome, Italy;
| | - Michele Lai
- Retrovirus Center and Virology Section, Department of Translational Research, University of Pisa, 56100 Pisa, Italy; (M.L.); (M.P.)
| | - Paola Ferrari
- Unit of Oncology, Department of Medical and Oncological Area, Azienda Ospedaliera—Universitaria Pisana, 56125 Pisa, Italy;
| | - Andrea Nicolini
- Department of Oncology, Transplantations and New Technologies in Medicine, University of Pisa, 56126 Pisa, Italy
| | - Mauro Pistello
- Retrovirus Center and Virology Section, Department of Translational Research, University of Pisa, 56100 Pisa, Italy; (M.L.); (M.P.)
| | - Beatrice Macchi
- Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy;
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3
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Andoh K, Nishimori A, Matsuura Y. The bovine leukemia virus-derived long non-coding RNA AS1-S binds to bovine hnRNPM and alters the interaction between hnRNPM and host mRNAs. Microbiol Spectr 2023; 11:e0085523. [PMID: 37671887 PMCID: PMC10581181 DOI: 10.1128/spectrum.00855-23] [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: 02/27/2023] [Accepted: 07/02/2023] [Indexed: 09/07/2023] Open
Abstract
Viruses utilize several strategies to cause latent infection and evade host immune responses. Long non-coding RNA (lncRNA), a class of non-protein-encoding RNA that regulates various cellular functions by interacting with RNA-binding proteins, plays important roles for viral latency in several viruses, such as herpesviruses and retroviruses, due to its lack of antigenicity. Bovine leukemia virus (BLV), which belongs to the family Retroviridae, encodes the BLV-derived lncRNA AS1-S, which is a major transcript expressed in latently infected cells. We herein identified bovine heterogeneous nuclear ribonucleoprotein M (hnRNPM), an RNA-binding protein located in the nucleus, as the binding partner of AS1-S using an RNA-protein pull-down assay. The pull-down assay using recombinant hnRNPM mutants showed that RNA recognition motifs (RRMs) 1 and 2, located in the N-terminal region of bovine hnRNPM, were responsible for the binding to AS1-S. Furthermore, RNA immunoprecipitation (RIP) assay results showed that the expression of AS1-S increased the number of mRNAs that co-immunoprecipitated with bovine hnRNPM in MDBK cells. These results suggested that AS1-S could alter the interaction between hnRNPM and host mRNAs, potentially interfering with cellular functions during the initial phase of mRNA maturation in the nucleus. Since most of the identified mRNAs that exhibited increased binding to hnRNPM were correlated with the KEGG term "Pathways in cancer," AS1-S might affect the proliferation and expansion of BLV-infected cells and contribute to tumor progression. IMPORTANCE BLV infects bovine B cells and causes malignant lymphoma, a disease that greatly affects the livestock industry. Due to its low incidence and long latent period, the molecular mechanisms underlying the progression of lymphoma remain enigmatic. Several non-coding RNAs (ncRNAs), such as miRNA and lncRNA, have recently been discovered in the BLV genome, and the relationship between BLV pathogenesis and these ncRNAs is attracting attention. However, most of the molecular functions of these transcripts remain unidentified. To the best of our knowledge, this is the first report describing a molecular function for the BLV-derived lncRNA AS1-S. The findings reported herein reveal a novel mechanism underlying BLV pathogenesis that could provide important insights for not only BLV research but also comparative studies of retroviruses.
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Affiliation(s)
- Kiyohiko Andoh
- National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Asami Nishimori
- National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Yuichi Matsuura
- National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
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Toyoda K, Yasunaga JI, Shichijo T, Arima Y, Tsujita K, Tanaka A, Salah T, Zhang W, Hussein O, Sonoda M, Watanabe M, Kurita D, Nakashima K, Yamada K, Miyoshi H, Ohshima K, Matsuoka M. HTLV-1 bZIP Factor-Induced Reprogramming of Lactate Metabolism and Epigenetic Status Promote Leukemic Cell Expansion. Blood Cancer Discov 2023; 4:374-393. [PMID: 37162520 PMCID: PMC10473166 DOI: 10.1158/2643-3230.bcd-22-0139] [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: 09/06/2022] [Revised: 03/17/2023] [Accepted: 04/26/2023] [Indexed: 05/11/2023] Open
Abstract
Acceleration of glycolysis is a common trait of cancer. A key metabolite, lactate, is typically secreted from cancer cells because its accumulation is toxic. Here, we report that a viral oncogene, HTLV-1 bZIP factor (HBZ), bimodally upregulates TAp73 to promote lactate excretion from adult T-cell leukemia-lymphoma (ATL) cells. HBZ protein binds to EZH2 and reduces its occupancy of the TAp73 promoter. Meanwhile, HBZ RNA activates TAp73 transcription via the BATF3-IRF4 machinery. TAp73 upregulates the lactate transporters MCT1 and MCT4. Inactivation of TAp73 leads to intracellular accumulation of lactate, inducing cell death in ATL cells. Furthermore, TAp73 knockout diminishes the development of inflammation in HBZ-transgenic mice. An MCT1/4 inhibitor, syrosingopine, decreases the growth of ATL cells in vitro and in vivo. MCT1/4 expression is positively correlated with TAp73 in many cancers, and MCT1/4 upregulation is associated with dismal prognosis. Activation of the TAp73-MCT1/4 pathway could be a common mechanism contributing to cancer metabolism. SIGNIFICANCE An antisense gene encoded in HTLV-1, HBZ, reprograms lactate metabolism and epigenetic modification by inducing TAp73 in virus-positive leukemic cells. A positive correlation between TAp73 and its target genes is also observed in many other cancer cells, suggesting that this is a common mechanism for cellular oncogenesis. This article is featured in Selected Articles from This Issue, p. 337.
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Affiliation(s)
- Kosuke Toyoda
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun-ichirou Yasunaga
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takafumi Shichijo
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yuichiro Arima
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
| | - Kenichi Tsujita
- Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Center for Metabolic Regulation of Healthy Aging (CMHA), Kumamoto University, Kumamoto, Japan
| | - Azusa Tanaka
- Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tarig Salah
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Wenyi Zhang
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Osama Hussein
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Miyu Sonoda
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Miho Watanabe
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Daisuke Kurita
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazutaka Nakashima
- Department of Pathology, Kurume University School of Medicine, Fukuoka, Japan
| | - Kyohei Yamada
- Department of Pathology, Kurume University School of Medicine, Fukuoka, Japan
| | - Hiroaki Miyoshi
- Department of Pathology, Kurume University School of Medicine, Fukuoka, Japan
| | - Koichi Ohshima
- Department of Pathology, Kurume University School of Medicine, Fukuoka, Japan
| | - Masao Matsuoka
- Department of Hematology, Rheumatology, and Infectious Disease, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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5
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Maksimova V, Wilkie T, Smith S, Phelps C, Melvin C, Yu L, Niewiesk S, Green PL, Panfil AR. HTLV-1 Hbz protein, but not hbz mRNA secondary structure, is critical for viral persistence and disease development. PLoS Pathog 2023; 19:e1011459. [PMID: 37327244 DOI: 10.1371/journal.ppat.1011459] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/05/2023] [Indexed: 06/18/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic cause of adult T-cell leukemia/lymphoma (ATL) and encodes a viral oncoprotein (Hbz) that is consistently expressed in asymptomatic carriers and ATL patients, suggesting its importance in the development and maintenance of HTLV-1 leukemic cells. Our previous work found Hbz protein is dispensable for virus-mediated T-cell immortalization but enhances viral persistence. We and others have also shown that hbz mRNA promotes T-cell proliferation. In our current studies, we evaluated the role of hbz mRNA on HTLV-1-mediated immortalization in vitro as well as in vivo persistence and disease development. We generated mutant proviral clones to examine the individual contributions of hbz mRNA, hbz mRNA secondary structure (stem-loop), and Hbz protein. Wild-type (WT) and all mutant viruses produced virions and immortalized T-cells in vitro. Viral persistence and disease development were also evaluated in vivo by infection of a rabbit model and humanized immune system (HIS) mice, respectively. Proviral load and sense and antisense viral gene expression were significantly lower in rabbits infected with mutant viruses lacking Hbz protein compared to WT or virus with an altered hbz mRNA stem-loop (M3 mutant). HIS mice infected with Hbz protein-deficient viruses showed significantly increased survival times compared to animals infected with WT or M3 mutant virus. Altered hbz mRNA secondary structure, or loss of hbz mRNA or protein, has no significant effect on T-cell immortalization induced by HTLV-1 in vitro; however, the Hbz protein plays a critical role in establishing viral persistence and leukemogenesis in vivo.
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Affiliation(s)
- Victoria Maksimova
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Tasha Wilkie
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Susan Smith
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Cameron Phelps
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Corrine Melvin
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Lianbo Yu
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Stefan Niewiesk
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Patrick L Green
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, Ohio, United States
| | - Amanda R Panfil
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, Ohio, United States
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6
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Plant E, Bellefroid M, Van Lint C. A complex network of transcription factors and epigenetic regulators involved in bovine leukemia virus transcriptional regulation. Retrovirology 2023; 20:11. [PMID: 37268923 PMCID: PMC10236774 DOI: 10.1186/s12977-023-00623-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/09/2023] [Indexed: 06/04/2023] Open
Abstract
Bovine Leukemia Virus (BLV) is the etiological agent of enzootic bovine leukosis, a disease characterized by the neoplastic proliferation of B cells in cattle. While most European countries have introduced efficient eradication programs, BLV is still present worldwide and no treatment is available. A major feature of BLV infection is the viral latency, which enables the escape from the host immune system, the maintenance of a persistent infection and ultimately the tumoral development. BLV latency is a multifactorial phenomenon resulting in the silencing of viral genes due to genetic and epigenetic repressions of the viral promoter located in the 5' Long Terminal Repeat (5'LTR). However, viral miRNAs and antisense transcripts are expressed from two different proviral regions, respectively the miRNA cluster and the 3'LTR. These latter transcripts are expressed despite the viral latency affecting the 5'LTR and are increasingly considered to take part in tumoral development. In the present review, we provide a summary of the experimental evidence that has enabled to characterize the molecular mechanisms regulating each of the three BLV transcriptional units, either through cis-regulatory elements or through epigenetic modifications. Additionally, we describe the recently identified BLV miRNAs and antisense transcripts and their implications in BLV-induced tumorigenesis. Finally, we discuss the relevance of BLV as an experimental model for the closely related human T-lymphotropic virus HTLV-1.
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Affiliation(s)
- Estelle Plant
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université Libre de Bruxelles (ULB), 6041, Gosselies, Belgium
| | - Maxime Bellefroid
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université Libre de Bruxelles (ULB), 6041, Gosselies, Belgium
| | - Carine Van Lint
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université Libre de Bruxelles (ULB), 6041, Gosselies, Belgium.
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7
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Romerio F. Origin and functional role of antisense transcription in endogenous and exogenous retroviruses. Retrovirology 2023; 20:6. [PMID: 37194028 DOI: 10.1186/s12977-023-00622-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/30/2023] [Indexed: 05/18/2023] Open
Abstract
Most proteins expressed by endogenous and exogenous retroviruses are encoded in the sense (positive) strand of the genome and are under the control of regulatory elements within the 5' long terminal repeat (LTR). A number of retroviral genomes also encode genes in the antisense (negative) strand and their expression is under the control of negative sense promoters within the 3' LTR. In the case of the Human T-cell Lymphotropic Virus 1 (HTLV-1), the antisense protein HBZ has been shown to play a critical role in the virus lifecycle and in the pathogenic process, while the function of the Human Immunodeficiency Virus 1 (HIV-1) antisense protein ASP remains unknown. However, the expression of 3' LTR-driven antisense transcripts is not always demonstrably associated with the presence of an antisense open reading frame encoding a viral protein. Moreover, even in the case of retroviruses that do express an antisense protein, such as HTLV-1 and the pandemic strains of HIV-1, the 3' LTR-driven antisense transcript shows both protein-coding and noncoding activities. Indeed, the ability to express antisense transcripts appears to be phylogenetically more widespread among endogenous and exogenous retroviruses than the presence of a functional antisense open reading frame within these transcripts. This suggests that retroviral antisense transcripts may have originated as noncoding molecules with regulatory activity that in some cases later acquired protein-coding function. Here, we will review examples of endogenous and exogenous retroviral antisense transcripts, and the ways through which they benefit viral persistence in the host.
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Affiliation(s)
- Fabio Romerio
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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8
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Scott TA, Soemardy C, Ray R, Morris K. Targeted zinc-finger repressors to the oncogenic HBZ gene inhibit adult T-cell leukemia (ATL) proliferation. NAR Cancer 2023; 5:zcac046. [PMID: 36644398 PMCID: PMC9832686 DOI: 10.1093/narcan/zcac046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/15/2022] [Accepted: 12/15/2022] [Indexed: 01/13/2023] Open
Abstract
Human T-lymphotropic virus type I (HTLV-I) infects CD4+ T-cells resulting in a latent, life-long infection in patients. Crosstalk between oncogenic viral factors results in the transformation of the host cell into an aggressive cancer, adult T-cell leukemia/lymphoma (ATL). ATL has a poor prognosis with no currently available effective treatments, urging the development of novel therapeutic strategies. Recent evidence exploring those mechanisms contributing to ATL highlights the viral anti-sense gene HTLV-I bZIP factor (HBZ) as a tumor driver and a potential therapeutic target. In this work, a series of zinc-finger protein (ZFP) repressors were designed to target within the HTLV-I promoter that drives HBZ expression at highly conserved sites covering a wide range of HTLV-I genotypes. ZFPs were identified that potently suppressed HBZ expression and resulted in a significant reduction in the proliferation and viability of a patient-derived ATL cell line with the induction of cell cycle arrest and apoptosis. These data encourage the development of this novel ZFP strategy as a targeted modality to inhibit the molecular driver of ATL, a possible next-generation therapeutic for aggressive HTLV-I associated malignancies.
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Affiliation(s)
- Tristan A Scott
- Center for Gene Therapy, City of Hope – Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope. 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Citradewi Soemardy
- Center for Gene Therapy, City of Hope – Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope. 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Roslyn M Ray
- Center for Gene Therapy, City of Hope – Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope. 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Kevin V Morris
- Menzies Health Institute Queensland, School of Pharmacy and Medical Science, Griffith University, Gold Coast Campus 4222, Australia
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9
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Zuo X, Zhou R, Yang S, Ma G. HTLV-1 persistent infection and ATLL oncogenesis. J Med Virol 2023; 95:e28424. [PMID: 36546414 DOI: 10.1002/jmv.28424] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/08/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is an oncogenic retrovirus; whereas HTLV-1 mainly persists in the infected host cell as a provirus, it also causes a malignancy called adult T-cell leukemia/lymphoma (ATLL) in about 5% of infection. HTLV-1 replication is in most cases silent in vivo and viral de novo infection rarely occurs; HTLV-1 rather relies on clonal proliferation of infected T cells for viral propagation as it multiplies the number of the provirus copies. It is mechanistically elusive how leukemic clones emerge during the course of HTLV-1 infection in vivo and eventually cause the onset of ATLL. This review summarizes our current understanding of HTLV-1 persistence and oncogenesis, with the incorporation of recent cutting-edge discoveries obtained by high-throughput sequencing.
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Affiliation(s)
- Xiaorui Zuo
- Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Ruoning Zhou
- Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Sikai Yang
- Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Guangyong Ma
- Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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10
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Liu Z, Larocque É, Xie Y, Xiao Y, Lemay G, Peloponese JM, Mesnard JM, Rassart É, Lin R, Zhou S, Zeng Y, Gao H, Cen S, Barbeau B. A newly identified interaction between nucleolar NPM1/B23 and the HTLV-I basic leucine zipper factor in HTLV-1 infected cells. Front Microbiol 2022; 13:988944. [PMID: 36532440 PMCID: PMC9753777 DOI: 10.3389/fmicb.2022.988944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/08/2022] [Indexed: 08/05/2023] Open
Abstract
Human T-cell leukemia virus type 1 is the causative agent of HTLV-1-associated myelopathy/tropical spastic paraparesis and adult T-cell leukemia-lymphoma (ATL). The HTLV-1 basic leucine zipper factor (HBZ) has been associated to the cancer-inducing properties of this virus, although the exact mechanism is unknown. In this study, we identified nucleophosmin (NPM1/B23) as a new interaction partner of HBZ. We show that sHBZ and the less abundant uHBZ isoform interact with nucleolar NPM1/B23 in infected cells and HTLV-1 positive patient cells, unlike equivalent antisense proteins of related non-leukemogenic HTLV-2, -3 and-4 viruses. We further demonstrate that sHBZ association to NPM1/B23 is sensitive to RNase. Interestingly, sHBZ was shown to interact with its own RNA. Through siRNA and overexpression experiments, we further provide evidence that NPM1/B23 acts negatively on viral gene expression with potential impact on cell transformation. Our results hence provide a new insight over HBZ-binding partners in relation to cellular localization and potential function on cell proliferation and should lead to a better understanding of the link between HBZ and ATL development.
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Affiliation(s)
- Zhenlong Liu
- Département de chimie, Université du Québec à Montréal, Montréal, QC, Canada
- Centre d’excellence en recherche sur les maladies orphelines-Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada
- Lady Davis Institute, Jewish General Hospital & Department of Medicine, McGill University, Montreal, QC, Canada
| | - Émilie Larocque
- Centre d’excellence en recherche sur les maladies orphelines-Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada
- Département de microbiologie et immunologie, Université de Montréal, Montréal, QC, Canada
| | - Yongli Xie
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing, China
| | - Yong Xiao
- Département de chimie, Université du Québec à Montréal, Montréal, QC, Canada
- Centre d’excellence en recherche sur les maladies orphelines-Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada
| | - Guy Lemay
- Département de microbiologie et immunologie, Université de Montréal, Montréal, QC, Canada
| | - Jean-Marie Peloponese
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université Montpellier, Montpellier, France
| | - Jean-Michel Mesnard
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université Montpellier, Montpellier, France
| | - Éric Rassart
- Centre d’excellence en recherche sur les maladies orphelines-Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada
- Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Rongtuan Lin
- Lady Davis Institute, Jewish General Hospital & Department of Medicine, McGill University, Montreal, QC, Canada
| | - Shuang Zhou
- Neurosurgery Department, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
| | - Yiming Zeng
- Neurosurgery Department, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
| | - Hongzhi Gao
- Neurosurgery Department, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing, China
| | - Benoit Barbeau
- Département de chimie, Université du Québec à Montréal, Montréal, QC, Canada
- Centre d’excellence en recherche sur les maladies orphelines-Fondation Courtois, Université du Québec à Montréal, Montréal, QC, Canada
- Département de microbiologie et immunologie, Université de Montréal, Montréal, QC, Canada
- Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
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11
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Kameda T, Shide K, Kamiunten A, Kogure Y, Morishita D, Koya J, Tahira Y, Akizuki K, Yokomizo-Nakano T, Kubota S, Marutsuka K, Sekine M, Hidaka T, Kubuki Y, Kitai Y, Matsuda T, Yoda A, Ohshima T, Sugiyama M, Sashida G, Kataoka K, Ogawa S, Shimoda K. CARD11 mutation and HBZ expression induce lymphoproliferative disease and adult T-cell leukemia/lymphoma. Commun Biol 2022; 5:1309. [PMID: 36446869 PMCID: PMC9709164 DOI: 10.1038/s42003-022-04284-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1). In addition to HTLV-1 bZIP factor (HBZ), a leukemogenic antisense transcript of HTLV-1, abnormalities of genes involved in TCR-NF-κB signaling, such as CARD11, are detected in about 90% of patients. Utilizing mice expressing CD4+ T cell-specific CARD11(E626K) and/or CD4+ T cell-specific HBZ, namely CARD11(E626K)CD4-Cre mice, HBZ transgenic (Tg) mice, and CARD11(E626K)CD4-Cre;HBZ Tg double transgenic mice, we clarify these genes' pathogenetic effects. CARD11(E626K)CD4-Cre and HBZ Tg mice exhibit lymphocytic invasion to many organs, including the lungs, and double transgenic mice develop lymphoproliferative disease and increase CD4+ T cells in vivo. CARD11(E626K) and HBZ cooperatively activate the non-canonical NF-κB pathway, IRF4 targets, BATF3/IRF4/HBZ transcriptional network, MYC targets, and E2F targets. Most KEGG and HALLMARK gene sets enriched in acute-type ATL are also enriched in double transgenic mice, indicating that these genes cooperatively contribute to ATL development.
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Affiliation(s)
- Takuro Kameda
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Kotaro Shide
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Ayako Kamiunten
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yasunori Kogure
- grid.272242.30000 0001 2168 5385Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan
| | | | - Junji Koya
- grid.272242.30000 0001 2168 5385Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan
| | - Yuki Tahira
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Keiichi Akizuki
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Takako Yokomizo-Nakano
- grid.274841.c0000 0001 0660 6749Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
| | - Sho Kubota
- grid.274841.c0000 0001 0660 6749Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
| | - Kosuke Marutsuka
- Department of Anatomic Pathology, Miyazaki Prefectural Miyazaki Hospital, Miyazaki, Japan
| | - Masaaki Sekine
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Tomonori Hidaka
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yoko Kubuki
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yuichi Kitai
- grid.39158.360000 0001 2173 7691Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido Japan
| | - Tadashi Matsuda
- grid.39158.360000 0001 2173 7691Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido Japan
| | - Akinori Yoda
- grid.258799.80000 0004 0372 2033Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan
| | - Takayuki Ohshima
- grid.412769.f0000 0001 0672 0015Faculty of Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University, Kagawa, Japan
| | | | - Goro Sashida
- grid.274841.c0000 0001 0660 6749Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
| | - Keisuke Kataoka
- grid.272242.30000 0001 2168 5385Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan ,grid.26091.3c0000 0004 1936 9959Division of Hematology, Department of Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Seishi Ogawa
- grid.258799.80000 0004 0372 2033Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan
| | - Kazuya Shimoda
- grid.410849.00000 0001 0657 3887Division of Hematology, Diabetes, and Endocrinology, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
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12
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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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13
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Tram J, Mesnard JM, Peloponese JM. Alternative RNA splicing in cancer: what about adult T-cell leukemia? Front Immunol 2022; 13:959382. [PMID: 35979354 PMCID: PMC9376482 DOI: 10.3389/fimmu.2022.959382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2022] Open
Abstract
Eukaryotic cells employ a broad range of mechanisms to regulate gene expression. Among others, mRNA alternative splicing is a key process. It consists of introns removal from an immature mRNA (pre-mRNA) via a transesterification reaction to create a mature mRNA molecule. Large-scale genomic studies have shown that in the human genome, almost 95% of protein-encoding genes go through alternative splicing and produce transcripts with different exons combinations (and sometimes retained introns), thus increasing the proteome diversity. Considering the importance of RNA regulation in cellular proliferation, survival, and differentiation, alterations in the alternative splicing pathway have been linked to several human cancers, including adult T-cell leukemia/lymphoma (ATL). ATL is an aggressive and fatal malignancy caused by the Human T-cell leukemia virus type 1 (HTLV-1). HTLV-1 genome encodes for two oncoproteins: Tax and HBZ, both playing significant roles in the transformation of infected cells and ATL onset. Here, we review current knowledge on alternative splicing and its link to cancers and reflect on how dysregulation of this pathway could participate in HTLV-1-induced cellular transformation and adult T-cell leukemia/lymphoma development.
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14
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Accolla RS. The Road to HTLV-1-Induced Leukemia by Following the Subcellular Localization of HTLV-1-Encoded HBZ Protein. Front Immunol 2022; 13:940131. [PMID: 35812456 PMCID: PMC9259882 DOI: 10.3389/fimmu.2022.940131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Human T cell leukemia virus-1 (HTLV-1) is the causative agent of a severe cancer of the lymphoid lineage that develops in 3-5% of infected individuals after many years. HTLV-1 infection may also induce a serious inflammatory pathology of the nervous system designated HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Two virus-encoded proteins, the viral transactivator Tax-1 and the HTLV-1 basic leucine-zipper factor HBZ, are strongly involved in the oncogenic process. Tax-1 is involved in initial phases of the oncogenic process. Conversely, HBZ seems to be involved in maintenance of the neoplastic state as witnessed by the generation of leukemic/lymphomatous phenotype in HBZ transgenic mice and the persistent expression of HBZ in all phases of the oncogenic process. Nevertheless, the intimate molecular and cellular mechanism mediated by the two viral proteins, particularly HBZ, in oncogenesis still remain elusive. An important step toward the complete comprehension of HBZ-associated oncogenicity is the clarification of the anatomical correlates of HBZ during the various phases of HTLV-1 infection to development of HTLV-1-associated inflammatory pathology and ultimately to the establishment of leukemia. In this review, I will summarize recent studies that have established for the first time a temporal and unidirectional expression of HBZ, beginning with an exclusive cytoplasmic localization in infected asymptomatic individuals and in HAM/TSP patients and ending to a progressive cytoplasmic-to-nuclear transition in leukemic cells. These results are framed within the present knowledge of HTLV-1 infection and the future lines of research that may shed new light on the complex mechanism of HTLV-1- mediated oncogenesis.
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15
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Toyoda K, Matsuoka M. Functional and Pathogenic Roles of Retroviral Antisense Transcripts. Front Immunol 2022; 13:875211. [PMID: 35572593 PMCID: PMC9100821 DOI: 10.3389/fimmu.2022.875211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
Exogenous retroviruses such as human immunodeficiency virus type 1 (HIV-1), human T-cell leukemia virus type 1 (HTLV-1) and bovine leukemia virus (BLV) can cause various diseases including immunodeficiency, inflammatory diseases and hematologic malignancies. These retroviruses persistently infect their hosts. Therefore, they need to evade host immune surveillance. One way in which these viruses might avoid immune detection is to utilize functional RNAs, rather than proteins, for certain activities, because RNAs are not recognized by the host immune system. HTLV-1 encodes the HTLV-1 bZIP factor (HBZ) gene in the antisense strand of the provirus. The HBZ protein is constantly expressed in HTLV-1 carriers and patients with adult T-cell leukemia-lymphoma, and it plays critical roles in pathogenesis. However, HBZ not only encodes this protein, but also functions as mRNA. Thus, HBZ gene mRNA is bifunctional. HIV-1 and BLV also encode long non-coding RNAs as antisense transcripts. In this review, we reshape our current understanding of how these antisense transcripts function and how they influence disease pathogenesis.
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16
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Miura M, Naito T, Saito M. Current Perspectives in Human T-Cell Leukemia Virus Type 1 Infection and Its Associated Diseases. Front Med (Lausanne) 2022; 9:867478. [PMID: 35463007 PMCID: PMC9024061 DOI: 10.3389/fmed.2022.867478] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/15/2022] [Indexed: 11/25/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is a replication-competent human retrovirus associated with two distinct types of diseases: a malignancy of mature CD4+ T cells called adult T-cell leukemia-lymphoma (ATL) and a chronic inflammatory central nervous system disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It was the first human retrovirus ever associated with a human cancer. Although most HTLV-1-infected individuals remain asymptomatic for life, a subpopulation develops ATL or HAM/TSP. Although the factors that cause these different manifestations of HTLV-1 infection are not fully understood, accumulating evidence suggests that the complex virus-host interactions, as well as the host immune response against HTLV-1 infection, appear to regulate the development of HTLV-1-associated diseases. This review outlines and discusses the current understanding, ongoing developments, and future perspectives of HTLV-1 research.
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17
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Nečasová I, Stojaspal M, Motyčáková E, Brom T, Janovič T, Hofr C. Transcriptional regulators of human oncoviruses: structural and functional implications for anticancer therapy. NAR Cancer 2022; 4:zcac005. [PMID: 35252867 PMCID: PMC8892037 DOI: 10.1093/narcan/zcac005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/04/2022] [Accepted: 02/15/2022] [Indexed: 11/26/2022] Open
Abstract
Transcription is often the first biosynthetic event of viral infection. Viruses produce preferentially viral transcriptional regulators (vTRs) essential for expressing viral genes and regulating essential host cell proteins to enable viral genome replication. As vTRs are unique viral proteins that promote the transcription of viral nucleic acid, vTRs interact with host proteins to suppress detection and immune reactions to viral infection. Thus, vTRs are promising therapeutic targets that are sequentially and structurally distinct from host cell proteins. Here, we review vTRs of three human oncoviruses: HBx of hepatitis B virus, HBZ of human T-lymphotropic virus type 1, and Rta of Epstein-Barr virus. We present three cunningly exciting and dangerous transcription strategies that make viral infections so efficient. We use available structural and functional knowledge to critically examine the potential of vTRs as new antiviral-anticancer therapy targets. For each oncovirus, we describe (i) the strategy of viral genome transcription; (ii) vTRs' structure and binding partners essential for transcription regulation; and (iii) advantages and challenges of vTR targeting in antiviral therapies. We discuss the implications of vTR regulation for oncogenesis and perspectives on developing novel antiviral and anticancer strategies.
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Affiliation(s)
- Ivona Nečasová
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Martin Stojaspal
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Edita Motyčáková
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Tomáš Brom
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Tomáš Janovič
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Ctirad Hofr
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
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18
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Navarro Borba MM, Santos LA, Neto RC, Oliveira Andrade FD, Salgado Á, de Almeida Rego FF, Júnior Alcantara LC, Farre L, Barreto FK. In silico analysis of human T-lymphotropic virus type 1 complete genomes from patients with different clinical outcomes. Future Virol 2022. [DOI: 10.2217/fvl-2021-0113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aims: This study aims to identify nucleotide variations in human T-lymphotropic virus type 1 (HTLV-1) proviral genome that might be related with the different clinical conditions associated to the virus. Materials & methods: 91 complete HTLV-1 genomes available in GenBank with their respective clinical information were subjected to in silico analyzes (subtyping, molecular characterization and machine learning). Results: We identified 22 mutations that seems to be important in patients’ clinical condition. The presence of some mutations demonstrated alterations in the proteins physicochemical profile, such as the P34L, present in the p12 protein. Furthermore, a correlation between mutations in long terminal repeat and pX region seems to be important for clinical manifestation. Conclusions: Some mutations have the potential to alter the conformation of viral proteins that are important for infection outcomes. Therefore, further functional studies should be performed to assess the impact of these variations on the pathogenesis and on the development of clinical manifestations associated with HTLV-1.
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Affiliation(s)
| | - Luciane Amorim Santos
- Instituto Gonçalo Moniz, Salvador, Brazil
- Escola Bahiana de Medicina e Saúde Pública, Salvador, Brazil
- Universidade Católica do Salvador, Salvador, Brazil
- Programa de Pós-graduação em Ciências da Saúde, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Brazil
| | | | | | - Álvaro Salgado
- Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Luiz Carlos Júnior Alcantara
- Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Lourdes Farre
- Institut Català d’Oncologia, Institut d’Investigació Biomédica de Bellvitge, Barcelona, Spain
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19
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Lin E, Panfil AR, Sandel G, Jain P. Novel perspectives on antisense transcription in HIV-1, HTLV-1, and HTLV-2. Front Microbiol 2022; 13:1042761. [PMID: 36620051 PMCID: PMC9822710 DOI: 10.3389/fmicb.2022.1042761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/24/2022] [Indexed: 12/25/2022] Open
Abstract
The genome of retroviruses contains two promoter elements (called long terminal repeat or LTR) at the 5' and 3' end of their genome. Although the expression of retroviral genes generally depends on the promoter located in the 5' LTR, the 3' LTR also has promoter activity responsible for producing antisense transcripts. These natural antisense transcripts (NATs) are a class of RNA molecules transcribed from the opposite strand of a protein-coding gene. NATs have been identified in many prokaryotic and eukaryotic systems, as well as in human retroviruses such as human immunodeficiency virus type 1 (HIV-1) and HTLV-1/2 (human T-cell leukemia virus type 1/2). The antisense transcripts of HIV-1, HTLV-1, and HTLV-2 have been briefly characterized over the past several years. However, a complete appreciation of the role these transcripts play in the virus lifecycle and the cellular factors which regulate their transcription is still lacking. This review provides an overview of antisense transcription in human retroviruses with a specific focus on the MEF-2 family of transcription factors, the function(s) of the antisense protein products, and the application of antisense transcription models in therapeutics against HIV-1 and HTLV-1 in the context of co-infection.
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Affiliation(s)
- Edward Lin
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Amanda R. Panfil
- Department of Veterinary Biosciences, Center for Retrovirus Research, The Ohio State University, Columbus, OH, United States
| | - Grace Sandel
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Pooja Jain
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- *Correspondence: Pooja Jain,
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20
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Epigenetic silencing of HTLV-1 expression by the HBZ RNA through interference with the basal transcription machinery. Blood Adv 2021; 4:5574-5579. [PMID: 33170933 DOI: 10.1182/bloodadvances.2020001675] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/17/2020] [Indexed: 01/22/2023] Open
Abstract
Key Points
By disrupting basal transcription machinery, HBZ RNA inhibits sense transcription of human T-cell leukemia virus type 1. Repression of genomic expression may allow entry into proviral latency and escape from immune response.
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21
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Li R, Sklutuis R, Groebner JL, Romerio F. HIV-1 Natural Antisense Transcription and Its Role in Viral Persistence. Viruses 2021; 13:v13050795. [PMID: 33946840 PMCID: PMC8145503 DOI: 10.3390/v13050795] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/11/2022] Open
Abstract
Natural antisense transcripts (NATs) represent a class of RNA molecules that are transcribed from the opposite strand of a protein-coding gene, and that have the ability to regulate the expression of their cognate protein-coding gene via multiple mechanisms. NATs have been described in many prokaryotic and eukaryotic systems, as well as in the viruses that infect them. The human immunodeficiency virus (HIV-1) is no exception, and produces one or more NAT from a promoter within the 3’ long terminal repeat. HIV-1 antisense transcripts have been the focus of several studies spanning over 30 years. However, a complete appreciation of the role that these transcripts play in the virus lifecycle is still lacking. In this review, we cover the current knowledge about HIV-1 NATs, discuss some of the questions that are still open and identify possible areas of future research.
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Affiliation(s)
- Rui Li
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
| | - Rachel Sklutuis
- HIV Dynamics and Replication Program, Host-Virus Interaction Branch, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (R.S.); (J.L.G.)
| | - Jennifer L. Groebner
- HIV Dynamics and Replication Program, Host-Virus Interaction Branch, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (R.S.); (J.L.G.)
| | - Fabio Romerio
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
- Correspondence:
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22
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Human retroviral antisense mRNAs are retained in the nuclei of infected cells for viral persistence. Proc Natl Acad Sci U S A 2021; 118:2014783118. [PMID: 33875584 DOI: 10.1073/pnas.2014783118] [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] [Indexed: 12/15/2022] Open
Abstract
Human retroviruses, including human T cell leukemia virus type 1 (HTLV-1) and HIV type 1 (HIV-1), encode an antisense gene in the negative strand of the provirus. Besides coding for proteins, the messenger RNAs (mRNAs) of retroviral antisense genes have also been found to regulate transcription directly. Thus, it has been proposed that retroviruses likely localize their antisense mRNAs to the nucleus in order to regulate nuclear events; however, this opposes the coding function of retroviral antisense mRNAs that requires a cytoplasmic localization for protein translation. Here, we provide direct evidence that retroviral antisense mRNAs are localized predominantly in the nuclei of infected cells. The retroviral 3' LTR induces inefficient polyadenylation and nuclear retention of antisense mRNA. We further reveal that retroviral antisense RNAs retained in the nucleus associate with chromatin and have transcriptional regulatory function. While HTLV-1 antisense mRNA is recruited to the promoter of C-C chemokine receptor type 4 (CCR4) and enhances transcription from it to support the proliferation of HTLV-1-infected cells, HIV-1 antisense mRNA is recruited to the viral LTR and inhibits sense mRNA expression to maintain the latency of HIV-1 infection. In summary, retroviral antisense mRNAs are retained in nucleus, act like long noncoding RNAs instead of mRNAs, and contribute to viral persistence.
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23
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Cucco MS, de Moraes LEP, de Oliveira Andrade F, Khouri R, Galvão-Castro B, Araujo THA, de Almeida Rego FF, Gois LL, Barreto FK, Santos LA. Molecular characterization of HTLV-1 genomic region hbz from patients with different clinical conditions. J Med Virol 2021; 93:6418-6423. [PMID: 33835501 DOI: 10.1002/jmv.27005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/19/2021] [Accepted: 03/31/2021] [Indexed: 01/19/2023]
Abstract
The human T-cell lymphotropic virus type-1 (HTLV-1) is associated with severe pathologies, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), adult T-cell leukemia-lymphoma (ATLL), and infective dermatitis associated with the HTLV-1 (IDH). Interestingly, HTLV-1 infection does not necessarily imply the development of pathological processes and it is unknown why some patients remain asymptomatic carriers (AC). Despite some mutations in the HTLV-1 genome appear to influence the outcome of HTLV-1, there are few studies that characterize molecularly the hbz region. This study aimed to perform the molecular characterization of hbz gene isolated from patients with different clinical outcomes. A total of 15 sequences were generated and analyzed with 571 sequences previously published. The analises showed that the R119Q mutation seems to be related to HTLV-1 clinical conditions since the frequency of this HBZ mutation is significantly different in comparison between AC with HAM/TSP and ATLL. The R119Q mutation is possibly a protective factor as the frequency is higher in AC sequences.
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Affiliation(s)
| | - Laise Eduarda Paixão de Moraes
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brasil.,Programa de Pós-graduação em Ciências da Saúde, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Bahia, Brasil
| | | | - Ricardo Khouri
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brasil.,Programa de Pós-graduação em Ciências da Saúde, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Bahia, Brasil
| | | | | | | | - Luana Leandro Gois
- Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brasil.,Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brasil.,Universidade Católica do Salvador, Salvador, Bahia, Brasil
| | | | - Luciane Amorim Santos
- Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brasil.,Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brasil.,Programa de Pós-graduação em Ciências da Saúde, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Bahia, Brasil.,Universidade Católica do Salvador, Salvador, Bahia, Brasil
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24
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Human T-cell lymphotropic virus HBZ and tax mRNA expression are associated with specific clinicopathological features in adult T-cell leukemia/lymphoma. Mod Pathol 2021; 34:314-326. [PMID: 32973330 DOI: 10.1038/s41379-020-00654-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022]
Abstract
Adult T-cell leukemia/lymphoma (ATLL) is caused by human T-cell leukemia virus type 1 (HTLV-1). HTLV-1-associated mRNA, including HBZ and tax, is deeply involved in the pathogenesis of ATLL. Using 88 ATLL tissue samples, we performed in situ mRNA analysis of HBZ and tax, and investigated its association with clinicopathological characteristics of ATLL. The median value of HBZ signals (/1000 ATLL cells) was 795.2 (range: 0.4-4013.1) and of tax signals (/1000 ATLL cells) was 5.1 (range: 0.1-891.2). The low-expression HBZ group displayed significant increase in the number of skin lesion (P = 0.0283). The high-expression tax group displayed significant increase in the number of PD-1-positive tumor-infiltrating lymphocytes (P < 0.0001). In addition, we identified patients with very high-expression of tax signals (400 or more signals/1000 ATLL cells). These patients displayed significant reductions in the expression of HLA class I (P = 0.0385) and β2M (P = 0.0124). Moreover, these patients displayed significantly poor overall survival (median survival time [MST] 7.7 months, 95% confidence interval [CI] [4.7-NA]), compared with the survival in patients with less than 400 tax signals (MST 22.6 months, 95% CI [13.7-41.7]) (P = 0.0499). These results suggest that Tax-mediated treatment of ATLL should be performed carefully in the high-expression tax group. More detailed studies could elucidate the clinicopathological significance of HBZ and tax mRNA expressions in ATLL.
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25
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Izaki M, Yasunaga JI, Nosaka K, Sugata K, Utsunomiya H, Suehiro Y, Shichijo T, Yamada A, Sugawara Y, Hibi T, Inomata Y, Akari H, Melamed A, Bangham C, Matsuoka M. In vivo dynamics and adaptation of HTLV-1-infected clones under different clinical conditions. PLoS Pathog 2021; 17:e1009271. [PMID: 33524072 PMCID: PMC7877780 DOI: 10.1371/journal.ppat.1009271] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/11/2021] [Accepted: 01/04/2021] [Indexed: 12/18/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) spreads through cell contact. Therefore, this virus persists and propagates within the host by two routes: clonal proliferation of infected cells and de novo infection. The proliferation is influenced by the host immune responses and expression of viral genes. However, the detailed mechanisms that control clonal expansion of infected cells remain to be elucidated. In this study, we show that newly infected clones were strongly suppressed, and then stable clones were selected, in a patient who was infected by live liver transplantation from a seropositive donor. Conversely, most HTLV-1+ clones persisted in patients who received hematopoietic stem cell transplantation from seropositive donors. To clarify the role of cell-mediated immunity in this clonal selection, we suppressed CD8+ or CD16+ cells in simian T-cell leukemia virus type 1 (STLV-1)-infected Japanese macaques. Decreasing CD8+ T cells had marginal effects on proviral load (PVL). However, the clonality of infected cells changed after depletion of CD8+ T cells. Consistent with this, PVL at 24 hours in vitro culture increased, suggesting that infected cells with higher proliferative ability increased. Analyses of provirus in a patient who received Tax-peptide pulsed dendritic cells indicate that enhanced anti-Tax immunity did not result in a decreased PVL although it inhibited recurrence of ATL. We postulate that in vivo selection, due to the immune response, cytopathic effects of HTLV-1 and intrinsic attributes of infected cells, results in the emergence of clones of HTLV-1-infected T cells that proliferate with minimized HTLV-1 antigen expression. HTLV-1 spreads in vivo through two routes: de novo infection and clonal proliferation of infected cells. Reverse transcriptase inhibitors and integrase inhibitors do not influence the PVL in HTLV-1-infected individuals, indicating that clonal proliferation is dominant to maintain and increase PVL in vivo in the chronic phase. It is assumed that the host immune responses are critical factors for clonal proliferation. We found that HTLV-1-infected clones dramatically changed during de novo infection whereas the clones in the chronic phase survived long-term after transplantation, indicating that HTLV-1-infected clones are selected for survival in vivo. Surprisingly, depletion of CD8+ cells had a small impact on PVL in a STLV-1 infected Japanese macaque, but modified the clonality of infected cells. The cells after depletion of CD8+ cells showed a higher proliferative activity during short-term in vitro culture. This study reveals that intrinsic attributes of selected clones contribute to clonal proliferation of infected cells.
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Affiliation(s)
- Mikiko Izaki
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun-ichirou Yasunaga
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Kisato Nosaka
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kenji Sugata
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Hayato Utsunomiya
- Department of Hematology, National Kyushu Cancer Center, Fukuoka, Japan
| | - Youko Suehiro
- Department of Hematology, National Kyushu Cancer Center, Fukuoka, Japan
| | - Takafumi Shichijo
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Asami Yamada
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yasuhiko Sugawara
- Department of Transplantation and Pediatric Surgery, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Taizo Hibi
- Department of Transplantation and Pediatric Surgery, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yukihiro Inomata
- Department of Transplantation and Pediatric Surgery, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hirofumi Akari
- Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan
| | - Anat Melamed
- Section of Virology, Department of Medicine, Imperial College London, London, United Kingdom
| | - Charles Bangham
- Section of Virology, Department of Medicine, Imperial College London, London, United Kingdom
| | - Masao Matsuoka
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- * E-mail:
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26
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Scott TA, Morris KV. Designer nucleases to treat malignant cancers driven by viral oncogenes. Virol J 2021; 18:18. [PMID: 33441159 PMCID: PMC7805041 DOI: 10.1186/s12985-021-01488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/02/2021] [Indexed: 11/22/2022] Open
Abstract
Viral oncogenic transformation of healthy cells into a malignant state is a well-established phenomenon but took decades from the discovery of tumor-associated viruses to their accepted and established roles in oncogenesis. Viruses cause ~ 15% of know cancers and represents a significant global health burden. Beyond simply causing cellular transformation into a malignant form, a number of these cancers are augmented by a subset of viral factors that significantly enhance the tumor phenotype and, in some cases, are locked in a state of oncogenic addiction, and substantial research has elucidated the mechanisms in these cancers providing a rationale for targeted inactivation of the viral components as a treatment strategy. In many of these virus-associated cancers, the prognosis remains extremely poor, and novel drug approaches are urgently needed. Unlike non-specific small-molecule drug screens or the broad-acting toxic effects of chemo- and radiation therapy, the age of designer nucleases permits a rational approach to inactivating disease-causing targets, allowing for permanent inactivation of viral elements to inhibit tumorigenesis with growing evidence to support their efficacy in this role. Although many challenges remain for the clinical application of designer nucleases towards viral oncogenes; the uniqueness and clear molecular mechanism of these targets, combined with the distinct advantages of specific and permanent inactivation by nucleases, argues for their development as next-generation treatments for this aggressive group of cancers.
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Affiliation(s)
- Tristan A Scott
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA.
| | - Kevin V Morris
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute at the City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA
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27
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Savoret J, Mesnard JM, Gross A, Chazal N. Antisense Transcripts and Antisense Protein: A New Perspective on Human Immunodeficiency Virus Type 1. Front Microbiol 2021; 11:625941. [PMID: 33510738 PMCID: PMC7835632 DOI: 10.3389/fmicb.2020.625941] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
It was first predicted in 1988 that there may be an Open Reading Frame (ORF) on the negative strand of the Human Immunodeficiency Virus type 1 (HIV-1) genome that could encode a protein named AntiSense Protein (ASP). In spite of some controversy, reports began to emerge some years later describing the detection of HIV-1 antisense transcripts, the presence of ASP in transfected and infected cells, and the existence of an immune response targeting ASP. Recently, it was established that the asp gene is exclusively conserved within the pandemic group M of HIV-1. In this review, we summarize the latest findings on HIV-1 antisense transcripts and ASP, and we discuss their potential functions in HIV-1 infection together with the role played by antisense transcripts and ASPs in some other viruses. Finally, we suggest pathways raised by the study of antisense transcripts and ASPs that may warrant exploration in the future.
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Affiliation(s)
- Juliette Savoret
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier, France
| | - Jean-Michel Mesnard
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier, France
| | - Antoine Gross
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier, France
| | - Nathalie Chazal
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, Université de Montpellier, Montpellier, France
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28
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Panfil AR, Green PL, Yoder KE. CRISPR Genome Editing Applied to the Pathogenic Retrovirus HTLV-1. Front Cell Infect Microbiol 2020; 10:580371. [PMID: 33425776 PMCID: PMC7785941 DOI: 10.3389/fcimb.2020.580371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 11/20/2020] [Indexed: 11/13/2022] Open
Abstract
CRISPR editing of retroviral proviruses has been limited to HIV-1. We propose human T-cell leukemia virus type 1 (HTLV-1) as an excellent model to advance CRISPR/Cas9 genome editing technologies against actively expressing and latent retroviral proviruses. HTLV-1 is a tumorigenic human retrovirus responsible for the development of both leukemia/lymphoma (ATL) and a neurological disease (HAM/TSP). The virus immortalizes and persists in CD4+ T lymphocytes that survive for the lifetime of the host. The most important drivers of HTLV-1-mediated transformation and proliferation are the tax and hbz viral genes. Tax, transcribed from the plus-sense or genome strand, is essential for de novo infection and cellular immortalization. Hbz, transcribed from the minus-strand, supports proliferation and survival of infected cells in both its protein and mRNA forms. Abrogating the function or expression of tax and/or hbz by genome editing and mutagenic double-strand break repair may disable HTLV-1-infected cell growth/survival and prevent immune modulatory effects and ultimately HTLV-1-associated disease. In addition, the HTLV-1 viral genome is highly conserved with remarkable sequence homogeneity, both within the same host and even among different HTLV isolates. This offers more focused guide RNA targeting. In addition, there are several well-established animal models for studying HTLV-1 infection in vivo as well as cell immortalization in vitro. Therefore, studies with HTLV-1 may provide a better basis to assess and advance in vivo genome editing against retroviral infections.
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Affiliation(s)
- Amanda R Panfil
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States.,Center for Retrovirus Research, The Ohio State University, Columbus, OH, United States
| | - Patrick L Green
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States.,Center for Retrovirus Research, The Ohio State University, Columbus, OH, United States
| | - Kristine E Yoder
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, United States.,Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH, United States
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29
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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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30
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Levy D, Ferreira MCMR, Reichert CO, de Almeida LV, Brocardo G, Lage LAPC, Culler HF, Nukui Y, Bydlowski SP, Pereira J. Cell Cycle Changes, DNA Ploidy, and PTTG1 Gene Expression in HTLV-1 Patients. Front Microbiol 2020; 11:1778. [PMID: 32793179 PMCID: PMC7393187 DOI: 10.3389/fmicb.2020.01778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/07/2020] [Indexed: 11/13/2022] Open
Abstract
Human T-cell lymphotropic virus type-1 (HTLV-1) is a pathogenic retrovirus that is associated with adult T-cell leukemia/lymphoma (ATL). Genetic instability is the hallmark of ATL. Cell cycle progression is needed for virus particle reproduction. HTLV-1 encoded Tax protein ultimately disrupts the mitotic spindle checkpoint, leading to incorrect chromosome segregation, resulting in aneuploidy. Cell cycle abnormalities have been described in T cells transfected with HTLV-1 virus in vitro, but not in HTLV-1 asymptomatic carriers. PTTG1 and HTLV-1 viral protein Tax exhibit a cooperative transforming activity. Overexpressed PTTG1 results in chromosome instability and aneuploidy, which has been suggested as a mechanism underlying PTTG1 transforming activity. Here we aimed to investigate cell cycle, DNA ploidy and PTTG1 mRNA expression in CD4+ and CD8+ T cells in healthy subjects (HS), HTLV-1 asymptomatic carriers and ATL patients. We have identified that HTLV-1 asymptomatic carriers have shown DNA aneuploidy and cell cycle arrest at cell cycle phase G0/G1 in CD4+ T cells. CD8+ T cells of HTLV-1 asymptomatic carriers also demonstrated DNA aneuploidy but without alteration in cell cycle. In ATL, CD4+ and CD8+ T cells present a higher number of cells in cell cycle S-phase and PTTG1 overexpression. These studies provide insight into malignant transformation of HTLV-1 asymptomatic carriers to ATL patients.
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Affiliation(s)
- Debora Levy
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), School of Medicine, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil
| | - Mari Cleia M R Ferreira
- Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Cadiele O Reichert
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), School of Medicine, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil
| | - Lis Vilela de Almeida
- Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Graciela Brocardo
- Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Luis Alberto P C Lage
- Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Hebert F Culler
- Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Youko Nukui
- Pro-Sangue Foundation, Department of Hematology, Hemotherapy and Cell Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Sergio P Bydlowski
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), School of Medicine, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil
| | - Juliana Pereira
- Laboratory of Medical Investigation on Pathogenesis and Targeted Therapy in Onco-Immuno-Hematology (LIM-31), School of Medicine, University of São Paulo, São Paulo, Brazil
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31
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Mohanty S, Harhaj EW. Mechanisms of Oncogenesis by HTLV-1 Tax. Pathogens 2020; 9:E543. [PMID: 32645846 PMCID: PMC7399876 DOI: 10.3390/pathogens9070543] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/24/2020] [Accepted: 07/01/2020] [Indexed: 01/23/2023] Open
Abstract
The human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATLL), a neoplasm of CD4+CD25+ T cells that occurs in 2-5% of infected individuals after decades of asymptomatic latent infection. Multiple HTLV-1-encoded regulatory proteins, including Tax and HTLV-1 basic leucine zipper factor (HBZ), play key roles in viral persistence and latency. The HTLV-1 Tax oncoprotein interacts with a plethora of host cellular proteins to regulate viral gene expression and also promote the aberrant activation of signaling pathways such as NF-κB to drive clonal proliferation and survival of T cells bearing the HTLV-1 provirus. Tax undergoes various post-translational modifications such as phosphorylation and ubiquitination that regulate its function and subcellular localization. Tax shuttles in different subcellular compartments for the activation of anti-apoptotic genes and deregulates the cell cycle with the induction of DNA damage for the accumulation of genomic instability that can result in cellular immortalization and malignant transformation. However, Tax is highly immunogenic and therefore HTLV-1 has evolved numerous strategies to tightly regulate Tax expression while maintaining the pool of anti-apoptotic genes through HBZ. In this review, we summarize the key findings on the oncogenic mechanisms used by Tax that set the stage for the development of ATLL, and the strategies used by HTLV-1 to tightly regulate Tax expression for immune evasion and viral persistence.
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Affiliation(s)
| | - Edward W. Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA;
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32
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Yasunaga JI. Strategies of Human T-Cell Leukemia Virus Type 1 for Persistent Infection: Implications for Leukemogenesis of Adult T-Cell Leukemia-Lymphoma. Front Microbiol 2020; 11:979. [PMID: 32508789 PMCID: PMC7248384 DOI: 10.3389/fmicb.2020.00979] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/23/2020] [Indexed: 01/21/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) establishes persistent infection in vivo in two distinct ways: de novo infection and clonal proliferation of infected cells. Two viral genes, Tax and HTLV-1 bZIP factor (HBZ) play critical roles in viral transcription and promotion of T-cell proliferation, respectively. Tax is a potent transactivator not only for viral transcription but also for many cellular oncogenic pathways, such as the NF-κB pathway. HBZ is a suppressor of viral transcription and has the potential to change the immunophenotype of infected cells, conferring an effector regulatory T cell (eTreg)-like signature (CD4+ CD25+ CCR4+ TIGIT+ Foxp3+) and enhancing the proliferation of this subset. Reports that mice transgenic for either gene develop malignant tumors suggest that both Tax and HBZ are involved in leukemogenesis by HTLV-1. However, the immunogenicity of Tax is very high, and its expression is generally suppressed in vivo. Recently, it was found that Tax can be expressed transiently in a small subpopulation of adult T-cell leukemia-lymphoma (ATL) cells and plays a critical role in maintenance of the overall population. HBZ is expressed in almost all infected cells except for the rare Tax-expressing cells, and activates the pathways associated with cell proliferation. These findings indicate that HTLV-1 fine-tunes the expression of viral genes to control the mode of viral propagation. The interplay between Tax and HBZ is the basis of a sophisticated strategy to evade host immune surveillance and increase transmission - and can lead to ATL as a byproduct.
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Affiliation(s)
- Jun-Ichirou Yasunaga
- Department of Hematology, Rheumatology and Infectious Disease, Faculty of Life Sciences, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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33
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Cells of adult T-cell leukemia evade HTLV-1 Tax/NF-κB hyperactivation-induced senescence. Blood Adv 2020; 3:564-569. [PMID: 30787019 DOI: 10.1182/bloodadvances.2018029322] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/18/2019] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL). The HTLV-1 viral trans-activator/oncoprotein Tax is a major driver of ATL, yet it induces rapid p21Cip1/Waf1 (p21)- and p27Kip1-mediated cellular senescence through constitutive activation (hyperactivation) of NF-κB. Although constitutive NF-κB activation is a common feature of T/B-cell leukemia/lymphoma, including ATL, it is not known how ATL cells maintain chronic NF-κB activation without undergoing senescence. Here, we demonstrate that, in contrast to HTLV-1- T-cell lines, ATL cell lines no longer undergo Tax-induced senescence. Although Tax+ and Tax- ATL cell lines showed signatures of constitutive NF-κB activation, their ability to progress through the cell cycle was unaffected. In some cases, ATL cell lines continued to proliferate despite significant upregulation of p21; additionally, many cell lines displayed altered expression of G1 and G1/S cyclins, particularly overexpression of cyclin D2. We propose that, during the course of ATL development, leukemia cells acquire genetic/epigenetic changes that can mitigate the senescence response triggered by NF-κB hyperactivation. Restoring the NF-κB-induced senescence response would likely help to control the development and progression of ATL and similar lymphoid malignancies.
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34
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Matsuoka M, Mesnard JM. HTLV-1 bZIP factor: the key viral gene for pathogenesis. Retrovirology 2020; 17:2. [PMID: 31915026 PMCID: PMC6950816 DOI: 10.1186/s12977-020-0511-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 01/02/2020] [Indexed: 12/26/2022] Open
Abstract
Human T cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia-lymphoma (ATL) and inflammatory diseases. The HTLV-1 bZIP factor (HBZ) gene is constantly expressed in HTLV-1 infected cells and ATL cells. HBZ protein suppresses transcription of the tax gene through blocking the LTR recruitment of not only ATF/CREB factors but also CBP/p300. HBZ promotes transcription of Foxp3, CCR4, and T-cell immunoreceptor with Ig and ITIM domains (TIGIT). Thus, HBZ is critical for the immunophenotype of infected cells and ATL cells. HBZ also functions in its RNA form. HBZ RNA suppresses apoptosis and promotes proliferation of T cells. Since HBZ RNA is not recognized by cytotoxic T cells, HTLV-1 has a clever strategy for avoiding immune detection. HBZ plays central roles in maintaining infected T cells in vivo and determining their immunophenotype.
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Affiliation(s)
- Masao Matsuoka
- Department of Hematology, Rheumatology and Infectious Diseases, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan. .,Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
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Miura M, Dey S, Ramanayake S, Singh A, Rueda DS, Bangham CRM. Kinetics of HTLV-1 reactivation from latency quantified by single-molecule RNA FISH and stochastic modelling. PLoS Pathog 2019; 15:e1008164. [PMID: 31738810 PMCID: PMC6886867 DOI: 10.1371/journal.ppat.1008164] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 12/02/2019] [Accepted: 10/29/2019] [Indexed: 01/16/2023] Open
Abstract
The human T cell leukemia virus HTLV-1 establishes a persistent infection in vivo in which the viral sense-strand transcription is usually silent at a given time in each cell. However, cellular stress responses trigger the reactivation of HTLV-1, enabling the virus to transmit to a new host cell. Using single-molecule RNA FISH, we measured the kinetics of the HTLV-1 transcriptional reactivation in peripheral blood mononuclear cells (PBMCs) isolated from HTLV-1+ individuals. The abundance of the HTLV-1 sense and antisense transcripts was quantified hourly during incubation of the HTLV-1-infected PBMCs ex vivo. We found that, in each cell, the sense-strand transcription occurs in two distinct phases: the initial low-rate transcription is followed by a phase of rapid transcription. The onset of transcription peaked between 1 and 3 hours after the start of in vitro incubation. The variance in the transcription intensity was similar in polyclonal HTLV-1+ PBMCs (with tens of thousands of distinct provirus insertion sites), and in samples with a single dominant HTLV-1+ clone. A stochastic simulation model was developed to estimate the parameters of HTLV-1 proviral transcription kinetics. In PBMCs from a leukemic subject with one dominant T-cell clone, the model indicated that the average duration of HTLV-1 sense-strand activation by Tax (i.e. the rapid transcription) was less than one hour. HTLV-1 antisense transcription was stable during reactivation of the sense-strand. The antisense transcript HBZ was produced at an average rate of ~0.1 molecules per hour per HTLV-1+ cell; however, between 20% and 70% of HTLV-1-infected cells were HBZ-negative at a given time, the percentage depending on the individual subject. HTLV-1-infected cells are exposed to a range of stresses when they are drawn from the host, which initiate the viral reactivation. We conclude that whereas antisense-strand transcription is stable throughout the stress response, the HTLV-1 sense-strand reactivation is highly heterogeneous and occurs in short, self-terminating bursts.
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Affiliation(s)
- Michi Miura
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Supravat Dey
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Saumya Ramanayake
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, United States of America
| | - David S. Rueda
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
- Single Molecule Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom
| | - Charles R. M. Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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36
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Ratner L. Biomarkers and Preclinical Models for Adult T-Cell Leukemia-Lymphoma Treatment. Front Microbiol 2019; 10:2109. [PMID: 31620102 PMCID: PMC6759749 DOI: 10.3389/fmicb.2019.02109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/27/2019] [Indexed: 11/13/2022] Open
Abstract
Adult T-cell leukemia/lymphoma (ATL) is an aggressive lymphoproliferative malignancy with a very poor prognosis. Despite several recent advances, new therapeutic approaches are critical, and this will require successful preclinical studies, including studies in ATL cell culture systems, and mouse models. Identification of accurate, reproducible biomarkers will be a crucial component of preclinical and clinical studies. This review summarizes the current state-of-the-art in each of these fields, and provides recommendations for future approaches. This problem is an important unmet need in HTLV research.
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Affiliation(s)
- Lee Ratner
- Division of Oncology, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
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Xiang J, Rauch DA, Huey DD, Panfil AR, Cheng X, Esser AK, Su X, Harding JC, Xu Y, Fox GC, Fontana F, Kobayashi T, Su J, Sundaramoorthi H, Wong WH, Jia Y, Rosol TJ, Veis DJ, Green PL, Niewiesk S, Ratner L, Weilbaecher KN. HTLV-1 viral oncogene HBZ drives bone destruction in adult T cell leukemia. JCI Insight 2019; 4:128713. [PMID: 31578308 DOI: 10.1172/jci.insight.128713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/04/2019] [Indexed: 12/16/2022] Open
Abstract
Osteolytic bone lesions and hypercalcemia are common, serious complications in adult T cell leukemia/lymphoma (ATL), an aggressive T cell malignancy associated with human T cell leukemia virus type 1 (HTLV-1) infection. The HTLV-1 viral oncogene HBZ has been implicated in ATL tumorigenesis and bone loss. In this study, we evaluated the role of HBZ on ATL-associated bone destruction using HTLV-1 infection and disease progression mouse models. Humanized mice infected with HTLV-1 developed lymphoproliferative disease and continuous, progressive osteolytic bone lesions. HTLV-1 lacking HBZ displayed only modest delays to lymphoproliferative disease but significantly decreased disease-associated bone loss compared with HTLV-1-infected mice. Gene expression array of acute ATL patient samples demonstrated increased expression of RANKL, a critical regulator of osteoclasts. We found that HBZ regulated RANKL in a c-Fos-dependent manner. Treatment of HTLV-1-infected humanized mice with denosumab, a monoclonal antibody against human RANKL, alleviated bone loss. Using patient-derived xenografts from primary human ATL cells to induce lymphoproliferative disease, we also observed profound tumor-induced bone destruction and increased c-Fos and RANKL gene expression. Together, these data show the critical role of HBZ in driving ATL-associated bone loss through RANKL and identify denosumab as a potential treatment to prevent bone complications in ATL patients.
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Affiliation(s)
- Jingyu Xiang
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel A Rauch
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Devra D Huey
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Amanda R Panfil
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Xiaogang Cheng
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alison K Esser
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xinming Su
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - John C Harding
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yalin Xu
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gregory C Fox
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Francesca Fontana
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Takayuki Kobayashi
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Junyi Su
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hemalatha Sundaramoorthi
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wing Hing Wong
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yizhen Jia
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Thomas J Rosol
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA.,Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
| | - Deborah J Veis
- Department of Medicine, Division of Bone and Mineral Diseases, St. Louis, Missouri, USA
| | - Patrick L Green
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Stefan Niewiesk
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Lee Ratner
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Katherine N Weilbaecher
- Department of Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
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Mota TM, Jones RB. HTLV-1 as a Model for Virus and Host Coordinated Immunoediting. Front Immunol 2019; 10:2259. [PMID: 31616431 PMCID: PMC6768981 DOI: 10.3389/fimmu.2019.02259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/06/2019] [Indexed: 12/17/2022] Open
Abstract
Immunoediting is a process that occurs in cancer, whereby the immune system acts to initially repress, and subsequently promote the outgrowth of tumor cells through the stages of elimination, equilibrium, and escape. Here we present a model for a virus that causes cancer where immunoediting is coordinated through synergistic viral- and host-mediated events. We argue that the initial viral replication process of the Human T cell leukemia virus type I (HTLV-1), which causes adult T cell leukemia/lymphoma (ATL) in ~5% of individuals after decades of latency, harmonizes with the host immune system to create a population of cells destined for malignancy. Furthermore, we explore the possibility for HIV to fit into this model of immunoediting, and propose a non-malignant escape phase for HIV-infected cells that persist beyond equilibrium.
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Affiliation(s)
- Talia M Mota
- Infectious Diseases Division, Department of Medicine, Weill Cornell Medical College, New York, NY, United States
| | - R Brad Jones
- Infectious Diseases Division, Department of Medicine, Weill Cornell Medical College, New York, NY, United States.,Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, NY, United States
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Harrod R. Silencers of HTLV-1 and HTLV-2: the pX-encoded latency-maintenance factors. Retrovirology 2019; 16:25. [PMID: 31492165 PMCID: PMC6731619 DOI: 10.1186/s12977-019-0487-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/30/2019] [Indexed: 11/10/2022] Open
Abstract
Of the members of the primate T cell lymphotropic virus (PTLV) family, only the human T-cell leukemia virus type-1 (HTLV-1) causes disease in humans—as the etiological agent of adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other auto-inflammatory disorders. Despite having significant genomic organizational and structural similarities, the closely related human T-cell lymphotropic virus type-2 (HTLV-2) is considered apathogenic and has been linked with benign lymphoproliferation and mild neurological symptoms in certain infected patients. The silencing of proviral gene expression and maintenance of latency are central for the establishment of persistent infections in vivo. The conserved pX sequences of HTLV-1 and HTLV-2 encode several ancillary factors which have been shown to negatively regulate proviral gene expression, while simultaneously activating host cellular proliferative and pro-survival pathways. In particular, the ORF-II proteins, HTLV-1 p30II and HTLV-2 p28II, suppress Tax-dependent transactivation from the viral promoter—whereas p30II also inhibits PU.1-mediated inflammatory-signaling, differentially augments the expression of p53-regulated metabolic/pro-survival genes, and induces lymphoproliferation which could promote mitotic proviral replication. The ubiquitinated form of the HTLV-1 p13II protein localizes to nuclear speckles and interferes with recruitment of the p300 coactivator by the viral transactivator Tax. Further, the antisense-encoded HTLV-1 HBZ and HTLV-2 APH-2 proteins and mRNAs negatively regulate Tax-dependent proviral gene expression and activate inflammatory signaling associated with enhanced T-cell lymphoproliferation. This review will summarize our current understanding of the pX latency-maintenance factors of HTLV-1 and HTLV-2 and discuss how these products may contribute to the differences in pathogenicity between the human PTLVs.
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Affiliation(s)
- Robert Harrod
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX, 75275-0376, USA.
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Forlani G, Baratella M, Tedeschi A, Pique C, Jacobson S, Accolla RS. HTLV-1 HBZ Protein Resides Exclusively in the Cytoplasm of Infected Cells in Asymptomatic Carriers and HAM/TSP Patients. Front Microbiol 2019; 10:819. [PMID: 31080441 PMCID: PMC6497793 DOI: 10.3389/fmicb.2019.00819] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/01/2019] [Indexed: 12/15/2022] Open
Abstract
Human T cell lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in a subset of infected subjects. Two viral proteins, Tax-1 and HTLV-1 basic leucine zipper factor (HBZ), play important roles in the pathogenesis of both diseases. We recently demonstrated that HBZ, previously considered a nuclear protein, is exclusively localized in the cytoplasm of peripheral blood mononuclear cells (PBMCs) of HAM/TSP patients. Here, the analysis of a larger panel of HAM/TSP cases confirmed that HBZ is a cytoplasmic protein, while Tax-1 preferentially localized in the cytoplasm with fewer speckle-like dots in the nucleus. More importantly, here we report for the first time that HBZ, when expressed in asymptomatic carriers (AC), is also confined in the cytoplasm. Similarly, Tax-1 was preferentially expressed in the cytoplasm in a significant proportion of AC. Interestingly, in both HAM/TSP and AC patients, the expression of HBZ and Tax-1 was rarely found in the same cell. We observed only few cases coexpressing the two oncoprotein in a very limited number of cells. In representative AC and HAM/TSP patients, cells expressing cytoplasmic HBZ were almost exclusively found in the CD4+ T cell compartment and very rarely in CD8+ T cells. Interestingly, at least in the cases analyzed, the expression of thymocite-expressed molecule involved in selection (THEMIS) is dispensable for the cytoplasmic localization of HBZ in both AC and HAM/TSP. The study of an HTLV-1-immortalized cell line established from an HAM/TSP patient confirmed HBZ as a resident cytoplasmic protein not shuttling between the cytoplasm and nucleus. These results extend our previous observation on the dichotomy of HBZ localization between HAM/TSP and ATL, pointing to the exclusive either cytoplasmic or nuclear localization in the two diseased states, respectively. Moreover, they show a rather selective expression in distinct cells of either HBZ or Tax-1. The unprecedented observation that HBZ is expressed only in the cytoplasm in AC strongly suggests a progressive modification of HBZ localization during the disease states associated to HTLV-1 infection. Future studies will clarify whether the distinct HBZ intracellular localization is a marker or a causative event of disease evolution.
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Affiliation(s)
- Greta Forlani
- Laboratories of General Pathology and Immunology “Giovanna Tosi,” Department of Medicine and Surgery, School of Medicine, University of Insubria, Varese, Italy
| | - Marco Baratella
- Laboratories of General Pathology and Immunology “Giovanna Tosi,” Department of Medicine and Surgery, School of Medicine, University of Insubria, Varese, Italy
| | - Alessandra Tedeschi
- Laboratories of General Pathology and Immunology “Giovanna Tosi,” Department of Medicine and Surgery, School of Medicine, University of Insubria, Varese, Italy
| | - Claudine Pique
- INSERM U1016, CNRS UMR 8104, Université Paris Descartes, Sorbonne Paris Cité, Institut Cochin, Paris, France
| | - Steve Jacobson
- Viral Immunology Section, Neuroimmunology Branch, NINDS/NIH, Bethesda, MD, United States
| | - Roberto S. Accolla
- Laboratories of General Pathology and Immunology “Giovanna Tosi,” Department of Medicine and Surgery, School of Medicine, University of Insubria, Varese, Italy
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Mori H, Tomiyasu T, Nishiyama K, Matsumoto M, Osawa Y, Okazaki K. L233P mutation in the bovine leukemia virus Tax protein depresses endothelial cell recruitment and tumorigenesis in athymic nude mice. Arch Virol 2019; 164:1343-1351. [DOI: 10.1007/s00705-019-04191-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/31/2019] [Indexed: 11/25/2022]
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42
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Molecular targeting for treatment of human T-lymphotropic virus type 1 infection. Biomed Pharmacother 2019; 109:770-778. [DOI: 10.1016/j.biopha.2018.10.139] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022] Open
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43
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[Astute strategies of HTLV-1 with driven viral genes]. Uirusu 2019; 69:37-46. [PMID: 32938893 DOI: 10.2222/jsv.69.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the world's first retrovirus with pathogenicity to cause adult T-cell leukemia-lymphoma (ATL) and chronic inflammatory diseases,such as HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and HTLV-1 uveitis. As the virological characteristic, HTLV-1 can transmit efficiently only through cell-to-cell contact. Spread of infection and viral persistence is ingeniously driven by several viral genes as exemplified by HTLV-1 bZIP factor (HBZ) and tax. After the infection, the virus promotes proliferation and immortalization of the infected cells with acculturating immunophenotype into effector/memory T cells. In addition, HBZ enhances expression of co-inhibitory receptors on the surface of infected cells, potentially leading to suppression of host immune responses. These viral strategies can also result in unforeseen by-product, the pathogenicity of HTLV-1-associated diseases. In this review, with recent progress of HTLV-1 researches, we focus on astute regulation systems of the viral genes developed by HTLV-1.
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Bangham CRM, Matsuoka M. Human T-cell leukaemia virus type 1: parasitism and pathogenesis. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0272. [PMID: 28893939 PMCID: PMC5597739 DOI: 10.1098/rstb.2016.0272] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
Human T-cell leukaemia virus type 1 (HTLV-1) causes not only adult T-cell leukaemia-lymphoma (ATL), but also inflammatory diseases including HTLV-1-associated myelopathy/tropical spastic paraparesis. HTLV-1 transmits primarily through cell-to-cell contact, and generates abundant infected cells in the host in order to survive and transmit to a new host. The resulting high proviral load is closely associated with the development of ATL and inflammatory diseases. To increase the number of infected cells, HTLV-1 changes the immunophenotype of infected cells, induces proliferation and inhibits apoptosis through the cooperative actions of two viral genes, tax and HTLV-1 bZIP factor (HBZ). As a result, infected cells survive, proliferate and infiltrate into the tissues, which is critical for transmission of the virus. Thus, the strategy of this virus is indivisibly linked with its pathogenesis, providing a clue for prevention and treatment of HTLV-1-induced diseases. This article is part of the themed issue ‘Human oncogenic viruses’.
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Affiliation(s)
- Charles R M Bangham
- Division of Infectious Diseases, Faculty of Medicine, Imperial College London, London W2 1PG, UK
| | - Masao Matsuoka
- Department of Hematology, Rheumatology, and Infectious Diseases, Kumamoto University Faculty of Life Sciences, 1-1-1 Honjo, Kumamoto 860-8556, Japan .,Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
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Tanaka A, Matsuoka M. HTLV-1 Alters T Cells for Viral Persistence and Transmission. Front Microbiol 2018; 9:461. [PMID: 29615995 PMCID: PMC5869182 DOI: 10.3389/fmicb.2018.00461] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 02/27/2018] [Indexed: 11/13/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) was the first retrovirus to be discovered as a causative agent of adult T-cell leukemia-lymphoma (ATL) and chronic inflammatory diseases. Two viral factors, Tax and HTLV-1 bZIP factor (HBZ), are thought to be involved in the leukemogenesis of ATL. Tax expression is frequently lost due to DNA methylation in the promoter region, genetic changes to the tax gene, and deletion of the 5′ long terminal repeat (LTR) in approximately half of all ATL cases. On the other hand, HBZ is expressed in all ATL cases. HBZ is known to function in both protein form and mRNA form, and both forms play an important role in the oncogenic process of HTLV-1. HBZ protein has a variety of functions, including the suppression of apoptosis, the promotion of proliferation, and the impairment of anti-viral activity, through the interaction with several host cellular proteins including p300/CBP, Foxp3, and Foxo3a. These functions dramatically modify the transcriptional profiling of host T cells. HBZ mRNA also promotes T cell proliferation and viability. HBZ changes infected T cells to CCR4+TIGIT+CD4+ effector/memory T cells. This unique immunophenotype enables T cells to migrate into various organs and tissues and to survive in vivo. In this review, we summarize how HBZ hijacks the transcriptional networks and immune systems of host T cells to contribute to HTLV-1 pathogenesis on the basis of recent new findings about HBZ and tax.
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Affiliation(s)
- Azusa Tanaka
- Department of Drug Discovery Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masao Matsuoka
- Department of Hematology, Rheumatology and Infectious Diseases, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.,Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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Gazon H, Chauhan P, Hamaidia M, Hoyos C, Li L, Safari R, Willems L. How Does HTLV-1 Undergo Oncogene-Dependent Replication Despite a Strong Immune Response? Front Microbiol 2018; 8:2684. [PMID: 29379479 PMCID: PMC5775241 DOI: 10.3389/fmicb.2017.02684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/26/2017] [Indexed: 12/16/2022] Open
Abstract
In 1987, Mitsuaki Yoshida proposed the following model (Yoshida and Seiki, 1987): “... T-cells activated through the endogenous p40x would express viral antigens including the envelope glycoproteins which are exposed on the cell surface. These glycoproteins are targets of host immune surveillance, as is evidenced by the cytotoxic effects of anti-envelope antibodies or patient sera. Eventually all cells expressing the viral antigens, that is, all cells driven by the p40x would be rejected by the host. Only those cells that did not express the viral antigens would survive. Later, these antigen-negative infected cells would begin again to express viral antigens, including p40x, thus entering into the second cycle of cell propagation. These cycles would be repeated in so-called healthy virus carriers for 20 or 30 years or longer....” Three decades later, accumulated experimental facts particularly on intermittent viral transcription and regulation by the host immune response appear to prove that Yoshida was right. This Hypothesis and Theory summarizes the evidences that support this paradigm.
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Affiliation(s)
- Hélène Gazon
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Pradeep Chauhan
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Malik Hamaidia
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Clotilde Hoyos
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Lin Li
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Roghaiyeh Safari
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
| | - Luc Willems
- National Fund for Scientific Research, Molecular and Cellular Epigenetics, Interdisciplinary Cluster for Applied Genoproteomics, Liège, Belgium.,Molecular Biology, TERRA, Gemboux Agro-Bio Tech, Gembloux, Belgium
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47
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Noncoding RNAs in Retrovirus Replication. RETROVIRUS-CELL INTERACTIONS 2018. [PMCID: PMC7173536 DOI: 10.1016/b978-0-12-811185-7.00012-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although a limited percentage of the genome produces proteins, approximately 90% is transcribed, indicating important roles for noncoding RNA (ncRNA). It is now known that these ncRNAs have a multitude of cellular functions ranging from the regulation of gene expression to roles as structural elements in ribonucleoprotein complexes. ncRNA is also represented at nearly every step of viral life cycles. This chapter will focus on ncRNAs of both host and viral origin and their roles in retroviral life cycles. Cellular ncRNA represents a significant portion of material packaged into retroviral virions and includes transfer RNAs, 7SL RNA, U RNA, and vault RNA. Initially thought to be random packaging events, these host RNAs are now proposed to contribute to viral assembly and infectivity. Within the cell, long ncRNA and endogenous retroviruses have been found to regulate aspects of the retroviral life cycle in diverse ways. Additionally, the HIV-1 transactivating response element RNA is thought to impact viral infection beyond the well-characterized role as a transcription activator. RNA interference, thought to be an early version of the innate immune response to viral infection, can still be observed in plants and invertebrates today. The ability of retroviral infection to manipulate the host RNAi pathway is described here. Finally, RNA-based therapies, including gene editing approaches, are being explored as antiretroviral treatments and are discussed.
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Abstract
Human T cell leukemia virus type 1 (HTLV-1), also known as human T lymphotropic virus type 1, was the first exogenous human retrovirus discovered. Unlike the distantly related lentivirus HIV-1, HTLV-1 causes disease in only 5-10% of infected people, depending on their ethnic origin. But whereas HIV-1 infection and the consequent diseases can be efficiently contained in most cases by antiretroviral drug treatment, there is no satisfactory treatment for the malignant or inflammatory diseases caused by HTLV-1. The purpose of the present article is to review recent advances in the understanding of the mechanisms by which the virus persists in vivo and causes disabling or fatal diseases.
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Affiliation(s)
- Charles R M Bangham
- Division of Infectious Diseases, Faculty of Medicine, Imperial College, London W2 1PG, United Kingdom;
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Positive and Negative Regulation of Type I Interferons by the Human T Cell Leukemia Virus Antisense Protein HBZ. J Virol 2017; 91:JVI.00853-17. [PMID: 28768861 DOI: 10.1128/jvi.00853-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/14/2017] [Indexed: 01/11/2023] Open
Abstract
The pathogenesis of human T cell leukemia virus type 1 (HTLV-1) is strongly linked to the viral regulatory proteins Tax1 and HBZ, whose opposing functions contribute to the clinical outcome of infection. Type I interferons alpha and beta (IFN-α and IFN-β) are key cytokines involved in innate immunity, and IFN-α, in combination with other antivirals, is extensively used in the treatment of HTLV-1 infection. The relationship between HTLV-1 and IFN signaling is unclear, and to date the effect of HBZ on this pathway has not been examined. Here we report that HBZ significantly enhances interferon regulatory factor 7 (IRF7)-induced IFN-α- and IFN-stimulated response element (ISRE) promoter activities and IFN-α production and can counteract the inhibitory effect of Tax1. In contrast to this, we show that HBZ and Tax1 cooperate to inhibit the induction of IFN-β and ISRE promoters by IRF3 and IFN-β production. In addition, we reveal that HBZ enhances ISRE activation by IFN-α. We further show that HBZ enhances IRF7 and suppresses IRF3 activation by TBK1 and IKKε. We demonstrate that HBZ has no effect on virus-induced nuclear accumulation of IRF3, suggesting that it may inhibit IRF3 activity at a transcriptional level. We show that HBZ physically interacts with IRF7 and IKKε but not with IRF3 or TBK1. Overall, our findings suggest that both HBZ and Tax1 are negative regulators of immediate early IFN-β innate immune responses, while HBZ but not Tax1 positively regulates the induction of IFN-α and downstream IFN-α signaling.IMPORTANCE Type I interferons are powerful antiviral cytokines and are used extensively in the treatment of HTLV-1-induced adult T cell leukemia (ATL). To date, the relationship between HTLV-1 and the IFN pathway is poorly understood, and studies so far have focused on Tax1. Our study is unique in that it examined the effect of HBZ, alone or in combination with Tax1, on type I IFN signaling. This is important because HBZ is frequently the only viral protein expressed in infected cells, particularly at later stages of infection. A better understanding of the how HBZ regulates IFN signaling may lead to the development of therapeutics that can modify such responses and improve the clinical outcome for infected individuals.
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Billman MR, Rueda D, Bangham CRM. Single-cell heterogeneity and cell-cycle-related viral gene bursts in the human leukaemia virus HTLV-1. Wellcome Open Res 2017. [DOI: 10.12688/wellcomeopenres.12469.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background: The human leukaemia virus HTLV-1 expresses essential accessory genes that manipulate the expression, splicing and transport of viral mRNAs. Two of these genes,taxandhbz, also promote proliferation of the infected cell, and both genes are thought to contribute to oncogenesis in adult T-cell leukaemia/lymphoma. The regulation of HTLV-1 proviral latency is not understood. tax,on the proviral plus strand, is usually silent in freshly-isolated cells, whereas the minus-strand-encodedhbzgene is persistently expressed at a low level. However, the persistently activated host immune response to Tax indicates frequent expression oftaxin vivo. Methods: We used single-molecule RNA-FISH to quantify the expression of HTLV-1 transcripts at the single-cell level in a total of >19,000 cells from five T-cell clones, naturally infected with HTLV-1, isolated by limiting dilution from peripheral blood of HTLV-1-infected subjects. Results: We found strong heterogeneity both within and between clones in the expression of the proviral plus-strand (detected by hybridization to thetaxgene) and the minus-strand (hbzgene). Both genes are transcribed in bursts;taxexpression is enhanced in the absence ofhbz, whilehbzexpression increased in cells with hightaxexpression. Surprisingly, we found thathbzexpression is strongly associated with the S and G2/M phases of the cell cycle, independent oftaxexpression. Contrary to current belief,hbzis not expressed in all cells at all times, even within one clone. Inhbz-positive cells, the abundance ofhbztranscripts showed a very strong positive linear correlation with nuclear volume.Conclusions: The occurrence of intense, intermittent plus-strand gene bursts in independent primary HTLV-1-infected T-cell clones from unrelated individuals strongly suggests that the HTLV-1 plus-strand is expressed in bursts in vivo. Our results offer an explanation for the paradoxical correlations observed between the host immune response and HTLV-1 transcription.
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