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Meissner ME, Talledge N, Mansky LM. Molecular Biology and Diversification of Human Retroviruses. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2022; 2:872599. [PMID: 35783361 PMCID: PMC9242851 DOI: 10.3389/fviro.2022.872599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Studies of retroviruses have led to many extraordinary discoveries that have advanced our understanding of not only human diseases, but also molecular biology as a whole. The most recognizable human retrovirus, human immunodeficiency virus type 1 (HIV-1), is the causative agent of the global AIDS epidemic and has been extensively studied. Other human retroviruses, such as human immunodeficiency virus type 2 (HIV-2) and human T-cell leukemia virus type 1 (HTLV-1), have received less attention, and many of the assumptions about the replication and biology of these viruses are based on knowledge of HIV-1. Existing comparative studies on human retroviruses, however, have revealed that key differences between these viruses exist that affect evolution, diversification, and potentially pathogenicity. In this review, we examine current insights on disparities in the replication of pathogenic human retroviruses, with a particular focus on the determinants of structural and genetic diversity amongst HIVs and HTLV.
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Affiliation(s)
- Morgan E. Meissner
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Molecular, Cellular, Developmental Biology and Genetics Graduate Program, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
| | - Nathaniel Talledge
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Division of Basic Sciences, School of Dentistry, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
| | - Louis M. Mansky
- Institute for Molecular Virology, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Division of Basic Sciences, School of Dentistry, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Molecular, Cellular, Developmental Biology and Genetics Graduate Program, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota – Twin Cities, Minneapolis, MN 55455 USA
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Brites C, Grassi MF, Quaresma JAS, Ishak R, Vallinoto ACR. Pathogenesis of HTLV-1 infection and progression biomarkers: An overview. Braz J Infect Dis 2021; 25:101594. [PMID: 34256025 PMCID: PMC9392164 DOI: 10.1016/j.bjid.2021.101594] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/12/2021] [Accepted: 06/03/2021] [Indexed: 12/12/2022] Open
Abstract
Infection by human T-cell lymphotropic virus type 1 (HTLV-1) occurs in lymphocytes, which travel throughout the body, thus affecting several target organs and causing varied clinical outcomes, particularly in populations that are underserved and do not have access to healthcare. However, the mechanism of pathogenesis is not yet fully understood. The TAX and HTLV-1 basic leucine zipper factor (HBZ) proteins maintain viral persistence and affect pathogenesis through cell proliferation and immune and inflammatory responses that accompany each clinical manifestation. TAX expression leads to inhibition of transcription error control, OX40 overexpression, and cell proliferation in adult T-cell leukemia (ATL). OX40 levels are elevated in the central nervous system (CNS), and the expression of TAX in the CNS causes neuronal damage and loss of immune reactivity among patients with HTLV-1-associated myelopathy (HAM). HBZ reduces viral replication and suppresses the immune response. Its cell compartmentalization has been associated with the pathogenesis of HAM (cytoplasmic localization) and ATL (nuclear localization). TAX and HBZ seem to act antagonistically in immune responses, affecting the pathogenesis of HTLV-1 infection. The progression from HTLV-1 infection to disease is a consequence of HTLV-1 replication in CD4+ T and CD8+ T lymphocytes and the imbalance between proinflammatory and anti-inflammatory cytokines. The compartmentalization of HBZ suggests that this protein may be an additional tool for assessing immune and inflammatory responses, in addition to those already recognized as potential biomarkers associated with progression from infection to disease (including human leukocyte antigen (HLA), killer immunoglobulin-like receptors (KIR), interleukin (IL)-6, IL-10, IL-28, Fas, Fas ligand, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and mannose-binding lectin).
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Affiliation(s)
- Carlos Brites
- Federal University of Bahia (UFBA), Professor Edgard Santos University Hospital Complex, Laboratory of Infectious Diseases Research, Salvador, BA, Brazil
| | | | | | - Ricardo Ishak
- Federal University of Pará (UFPA), Institute of Biological Sciences, Laboratory of Virology, Belém, PA, Brazil
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Schnell AP, Kohrt S, Thoma-Kress AK. Latency Reversing Agents: Kick and Kill of HTLV-1? Int J Mol Sci 2021; 22:ijms22115545. [PMID: 34073995 PMCID: PMC8197370 DOI: 10.3390/ijms22115545] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/14/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1), the cause of adult T-cell leukemia/lymphoma (ATLL), is a retrovirus, which integrates into the host genome and persistently infects CD4+ T-cells. Virus propagation is stimulated by (1) clonal expansion of infected cells and (2) de novo infection. Viral gene expression is induced by the transactivator protein Tax, which recruits host factors like positive transcription elongation factor b (P-TEFb) to the viral promoter. Since HTLV-1 gene expression is repressed in vivo by viral, cellular, and epigenetic mechanisms in late phases of infection, HTLV-1 avoids an efficient CD8+ cytotoxic T-cell (CTL) response directed against the immunodominant viral Tax antigen. Hence, therapeutic strategies using latency reversing agents (LRAs) sought to transiently activate viral gene expression and antigen presentation of Tax to enhance CTL responses towards HTLV-1, and thus, to expose the latent HTLV-1 reservoir to immune destruction. Here, we review strategies that aimed at enhancing Tax expression and Tax-specific CTL responses to interfere with HTLV-1 latency. Further, we provide an overview of LRAs including (1) histone deacetylase inhibitors (HDACi) and (2) activators of P-TEFb, that have mainly been studied in context of human immunodeficiency virus (HIV), but which may also be powerful in the context of HTLV-1.
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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: 1.8] [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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Aberrant Splicing Events and Epigenetics in Viral Oncogenomics: Current Therapeutic Strategies. Cells 2021; 10:cells10020239. [PMID: 33530521 PMCID: PMC7910916 DOI: 10.3390/cells10020239] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023] Open
Abstract
Global cancer incidence and mortality are on the rise. Although cancer is fundamentally a non-communicable disease, a large number of cancers are known to have a viral aetiology. A high burden of infectious agents (Human immunodeficiency virus (HIV), human papillomavirus (HPV), hepatitis B virus (HBV)) in certain Sub-Saharan African countries drives the rates of certain cancers. About one-third of all cancers in Africa are attributed to infection. Seven viruses have been identified with carcinogenic characteristics, namely the HPV, HBV, Hepatitis C virus (HCV), Epstein–Barr virus (EBV), Human T cell leukaemia virus 1 (HTLV-1), Kaposi’s Sarcoma Herpesvirus (KSHV), and HIV-1. The cellular splicing machinery is compromised upon infection, and the virus generates splicing variants that promote cell proliferation, suppress signalling pathways, inhibition of tumour suppressors, alter gene expression through epigenetic modification, and mechanisms to evade an immune response, promoting carcinogenesis. A number of these splice variants are specific to virally-induced cancers. Elucidating mechanisms underlying how the virus utilises these splice variants to maintain its latent and lytic phase will provide insights into novel targets for drug discovery. This review will focus on the splicing genomics, epigenetic modifications induced by and current therapeutic strategies against HPV, HBV, HCV, EBV, HTLV-1, KSHV and HIV-1.
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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: 14] [Impact Index Per Article: 3.5] [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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Casseb J, Janini LM, Barros Kanzaki LI, Lopes LR, Paiva AM. Is the human T-cell lymphotropic virus type 2 in the process of endogenization into the human genome? J Virus Erad 2020; 6:100009. [PMID: 33294211 PMCID: PMC7695812 DOI: 10.1016/j.jve.2020.100009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 12/30/2022] Open
Abstract
Human T-cell lymphotropic virus type 2 (HTLV-2) infection has been shown to be endemic among intravenous drug users in parts of North America, Europe and Southeast Asia and in a number of Amerindian populations. Despite a 65% genetic similarity and common host humoral response, the human T-cell lymphotropic viruses type 1 (HTLV-1) and 2 display different mechanisms of host interaction and capacity for disease development. While HTLV-1 pathogenicity is well documented, HTLV-2 etiology in human disease is not clearly established. From an evolutionary point of view, its introduction and integration into the germ cell chromosomes of host species could be considered as the final stage of parasitism and evasion from host immunity. The extraordinary abundance of endogenous viral sequences in all vertebrate species genomes, including the hominid family, provides evidence of this invasion. Some of these gene sequences still retain viral characteristics and the ability to replicate and hence are potentially able to elicit responses from the innate and adaptive host immunity, which could result in beneficial or pathogenic effects. Taken together, this data may indicate that HTLV-2 is more likely to progress towards endogenization as has happened to the human endogenous retroviruses millions of years ago. Thus, this intimate association (HTLV-2/human genome) may provide protection from the immune system with better adaptation and low pathogenicity.
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Affiliation(s)
- Jorge Casseb
- Institute of Tropical Medicine of Sao Paulo - University of Sao Paulo, Laboratory of Medical Investigation LIM-56 / Faculty of Medicine -USP, Brazil
| | - Luiz Mario Janini
- Discipline of Microbiology, Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo - Unifesp, Sao Paulo, SP, Brazil
| | - Luis Isamu Barros Kanzaki
- Laboratory of Bioprospection, Department of Pharmacy, Faculty of Health. Sciences, University of Brasilia, DF, Brazil
| | - Luciano Rodrigo Lopes
- Bioinformatics and Biomedical Data Science Division, Health Informatics Department, Federal University of Sao Paulo - Unifesp, São Paulo, SP, Brazil
| | - Arthur Maia Paiva
- Institute of Tropical Medicine of Sao Paulo - University of Sao Paulo, Laboratory of Medical Investigation LIM-56 / Faculty of Medicine -USP, Brazil.,University Hospital Alberto Antunes / Federal University of Alagoas, Brazil
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Newman RA, Sastry KJ, Arav-Boger R, Cai H, Matos R, Harrod R. Antiviral Effects of Oleandrin. J Exp Pharmacol 2020; 12:503-515. [PMID: 33262663 PMCID: PMC7686471 DOI: 10.2147/jep.s273120] [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: 09/04/2020] [Accepted: 10/25/2020] [Indexed: 12/13/2022] Open
Abstract
Over the past 15 years, investigators have reported on the utility and safety of cardiac glycosides for numerous health benefits including those as treatments for malignant disease, stroke-mediated ischemic injury and certain neurodegenerative diseases. In addition to those, there is a growing body of evidence for novel antiviral effects of selected cardiac glycoside molecules. One unique cardiac glycoside, oleandrin derived from Nerium oleander, has been reported to have antiviral activity specifically against 'enveloped' viruses including HIV and HTLV-1. Importantly, a recent publication has presented in vitro evidence for oleandrin's ability to inhibit production of infectious virus particles when used for treatment prior to, as well as after infection by SARS-CoV-2/COVID-19. This review will highlight the known in vitro antiviral effects of oleandrin as well as present previously unpublished effects of this novel cardiac glycoside against Ebola virus, Cytomegalovirus, and Herpes simplex viruses.
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Affiliation(s)
- Robert A Newman
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77054, USA.,Phoenix Biotechnology, Inc, San Antonio, TX 78217, USA
| | - K Jagannadha Sastry
- Departments of Thoracic, Head and Neck Medical Oncology and Veterinary Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ravit Arav-Boger
- Division of Infectious Diseases, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Hongyi Cai
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Robert Harrod
- Department of Biological Sciences, the Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, Dallas, TX 75275, USA
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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: 26] [Impact Index Per Article: 5.2] [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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Omsland M, Silic-Benussi M, Moles R, Sarkis S, Purcell DFJ, Yurick D, Khoury G, D'Agostino DM, Ciminale V, Franchini G. Functional properties and sequence variation of HTLV-1 p13. Retrovirology 2020; 17:11. [PMID: 32398094 PMCID: PMC7218495 DOI: 10.1186/s12977-020-00517-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/10/2020] [Indexed: 01/06/2023] Open
Abstract
Human T cell leukemia virus type-1 (HTLV-1) was the first retrovirus found to cause cancer in humans, but the mechanisms that drive the development of leukemia and other diseases associated with HTLV-1 infection remain to be fully understood. This review describes the functional properties of p13, an 87-amino acid protein coded by HTLV-1 open reading frame II (orf-II). p13 is mainly localized in the inner membrane of the mitochondria, where it induces potassium (K+) influx and reactive oxygen species (ROS) production, which can trigger either proliferation or apoptosis, depending on the ROS setpoint of the cell. Recent evidence indicates that p13 may influence the cell’s innate immune response to viral infection and the infected cell phenotype. Association of the HTLV-1 transcriptional activator, Tax, with p13 increases p13’s stability, leads to its partial co-localization with Tax in nuclear speckles, and reduces the ability of Tax to interact with the transcription cofactor CBP/p300. Comparison of p13 sequences isolated from HTLV-1-infected individuals revealed a small number of amino acid variations in the domains controlling the subcellular localization of the protein. Disruptive mutations of p13 were found in samples obtained from asymptomatic patients with low proviral load. p13 sequences of HTLV-1 subtype C isolates from indigenous Australian patients showed a high degree of identity among each other, with all samples containing a pattern of 5 amino acids that distinguished them from other subtypes. Further characterization of p13’s functional properties and sequence variants may lead to a deeper understanding of the impact of p13 as a contributor to the clinical manifestations of HTLV-1 infection.
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Affiliation(s)
- Maria Omsland
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Ramona Moles
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Damian F J Purcell
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia
| | - David Yurick
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia
| | - Georges Khoury
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia.,Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | | | - Vincenzo Ciminale
- Veneto Institute of Oncology IOV-IRCCS, Padua, Italy.,Department of Surgery, Oncology, and Gastroenterology, University of Padua, Padua, Italy
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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