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Haines RA, Urbiztondo RA, Haynes RAH, Simpson E, Niewiesk S, Lairmore MD. Characterization of New Zealand White Rabbit Gut-Associated Lymphoid Tissues and Use as Viral Oncology Animal Model. ILAR J 2017; 57:34-43. [PMID: 27034393 DOI: 10.1093/ilar/ilw004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Rabbits have served as a valuable animal model for the pathogenesis of various human diseases, including those related to agents that gain entry through the gastrointestinal tract such as human T cell leukemia virus type 1. However, limited information is available regarding the spatial distribution and phenotypic characterization of major rabbit leukocyte populations in mucosa-associated lymphoid tissues. Herein, we describe the spatial distribution and phenotypic characterization of leukocytes from gut-associated lymphoid tissues (GALT) from 12-week-old New Zealand White rabbits. Our data indicate that rabbits have similar distribution of leukocyte subsets as humans, both in the GALT inductive and effector sites and in mesenteric lymph nodes, spleen, and peripheral blood. GALT inductive sites, including appendix, cecal tonsil, Peyer's patches, and ileocecal plaque, had variable B cell/T cell ratios (ranging from 4.0 to 0.8) with a predominance of CD4 T cells within the T cell population in all four tissues. Intraepithelial and lamina propria compartments contained mostly T cells, with CD4 T cells predominating in the lamina propria compartment and CD8 T cells predominating in the intraepithelial compartment. Mesenteric lymph node, peripheral blood, and splenic samples contained approximately equal percentages of B cells and T cells, with a high proportion of CD4 T cells compared with CD8 T cells. Collectively, our data indicate that New Zealand White rabbits are comparable with humans throughout their GALT and support future studies that use the rabbit model to study human gut-associated disease or infectious agents that gain entry by the oral route.
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Affiliation(s)
- Robyn A Haines
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
| | - Rebeccah A Urbiztondo
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
| | - Rashade A H Haynes
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
| | - Elaine Simpson
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
| | - Stefan Niewiesk
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
| | - Michael D Lairmore
- Robyn A. Haines, DVM, was a PhD student; Rebeccah A. Urbiztondo, DVM, was a Master's student; Rashade A. H. Haynes, PhD, was a postdoctoral fellow; and Elaine Simpson, DVM, was a summer research student in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio. Stefan Niewiesk, PhD, DVM, is professor in the Department of Veterinary Biosciences at The Ohio State University is Columbus, Ohio. Michael D. Lairmore, DVM, PhD, is dean, in the School of Veterinary Medicine at the University of California, Davis in Davis, California
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Lairmore MD, Niewiesk S. Models of Virus-Induced Carcinogenesis and Oncolytic Viruses. ILAR J 2016; 57:1-2. [PMID: 27034389 DOI: 10.1093/ilar/ilw003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael D Lairmore
- Michael D. Lairmore, DVM, PhD, is dean and distinguished professor in the School of Veterinary Medicine at the University of California-Davis in Davis, California. Stefan Niewiesk, DVM, PhD, is a professor in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio
| | - Stefan Niewiesk
- Michael D. Lairmore, DVM, PhD, is dean and distinguished professor in the School of Veterinary Medicine at the University of California-Davis in Davis, California. Stefan Niewiesk, DVM, PhD, is a professor in the Department of Veterinary Biosciences at The Ohio State University in Columbus, Ohio
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Lairmore MD, Ilkiw J. Animals Used in Research and Education, 1966-2016: Evolving Attitudes, Policies, and Relationships. J Vet Med Educ 2015; 42:425-440. [PMID: 26673210 DOI: 10.3138/jvme.0615-087r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Since the inception of the Association of American Veterinary Medical Colleges (AAVMC), the use of animals in research and education has been a central element of the programs of member institutions. As veterinary education and research programs have evolved over the past 50 years, so too have societal views and regulatory policies. AAVMC member institutions have continually responded to these events by exchanging best practices in training their students in the framework of comparative medicine and the needs of society. Animals provide students and faculty with the tools to learn the fundamental knowledge and skills of veterinary medicine and scientific discovery. The study of animal models has contributed extensively to medicine, veterinary medicine, and basic sciences as these disciplines seek to understand life processes. Changing societal views over the past 50 years have provided active examination and continued refinement of the use of animals in veterinary medical education and research. The future use of animals to educate and train veterinarians will likely continue to evolve as technological advances are applied to experimental design and educational systems. Natural animal models of both human and animal health will undoubtedly continue to serve a significant role in the education of veterinarians and in the development of new treatments of animal and human disease. As it looks to the future, the AAVMC as an organization will need to continue to support and promote best practices in the humane care and appropriate use of animals in both education and research.
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MESH Headings
- Animal Experimentation/history
- Animal Experimentation/legislation & jurisprudence
- Animal Use Alternatives/history
- Animal Use Alternatives/legislation & jurisprudence
- Animal Use Alternatives/trends
- Animal Welfare/history
- Animal Welfare/legislation & jurisprudence
- Animals
- Animals, Laboratory
- Education, Veterinary/history
- Education, Veterinary/methods
- Education, Veterinary/trends
- History, 18th Century
- History, 19th Century
- History, 20th Century
- History, 21st Century
- History, Ancient
- Human-Animal Bond
- Humans
- Models, Animal
- United States
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Abstract
Bovine leukemia virus (BLV) and human T-lymphotrophic virus type-1 (HTLV-1) are related retroviruses associated with persistent and lifelong infections and a low incidence of lymphomas within their hosts. Both viruses can be spread through contact with bodily fluids containing infected cells, most often from mother to offspring through breast milk. Each of these complex retroviruses contains typical gag, pol, and env genes but also unique, nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the pathogenesis of each virus. Comparisons of BLV and HTLV-1 provide insights into mechanisms of spread and tumor formation, as well as potential approaches to therapeutic intervention against the infections.
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Affiliation(s)
- Michael D Lairmore
- School of Veterinary Medicine, University of California, Davis, California, 95616;
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Doueiri R, Anupam R, Kvaratskhelia M, Green KB, Lairmore MD, Green PL. Comparative host protein interactions with HTLV-1 p30 and HTLV-2 p28: insights into difference in pathobiology of human retroviruses. Retrovirology 2012; 9:64. [PMID: 22876852 PMCID: PMC3464894 DOI: 10.1186/1742-4690-9-64] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 07/11/2012] [Indexed: 02/02/2023] Open
Abstract
Background Human T lymphotropic virus type-1 (HTLV-1) and type 2 (HTLV-2) are closely related human retroviruses, but have unique disease associations. HTLV-1 is the causative agent of an aggressive T-cell leukemia known as adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other inflammatory diseases. HTLV-2 infection has not been clearly associated with any disease condition. Although both viruses can transform T cells in vitro, the HTLV-1 provirus is mainly detected in CD4+ T cells whereas HTLV-2 is mainly detected in CD8+ T cells of infected individuals. HTLV-1 and HTLV-2 encode accessory proteins p30 and p28, respectively, which share partial amino acid homology and are required for viral persistence in vivo. The goal of this study was to identify host proteins interacting with p30 and p28 in order to understand their role in pathogenesis. Results Affinity-tag purification coupled with mass spectrometric (MS) analyses revealed 42 and 22 potential interacting cellular partners of p30 and p28, respectively. Of these, only three cellular proteins, protein arginine methyltransferase 5 (PRMT5), hnRNP K and 60 S ribosomal protein L8 were detected in both p30 and p28 fractions. To validate the proteomic results, four interacting proteins were selected for further analyses using immunoblot assays. In full agreement with the MS analysis two cellular proteins REGγ and NEAF-interacting protein 30 (NIP30) selectively interacted with p30 and not with p28; heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) bound to p28 and not to p30; and PRMT5 interacted with both p30 and p28. Further studies demonstrated that reduced levels of PRMT5 resulted in decreased HTLV-2 viral gene expression whereas the viral gene expression of HTLV-1 was unchanged. Conclusion The comparisons of p30 and p28 host protein interaction proteome showed striking differences with some degree of overlap. PRMT5, one of the host proteins that interacted with both p30 and p28 differentially affected HTLV-1 and HTLV-2 viral gene expression suggesting that PRMT5 is involved at different stages of HTLV-1 and HTLV-2 biology. These findings suggest that distinct host protein interaction profiles of p30 and p28 could, in part, be responsible for differences in HTLV-1 and HTLV-2 pathobiology. This study provides new avenues of investigation into mechanisms of viral infection, tropism and persistence.
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Affiliation(s)
- Rami Doueiri
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
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Lairmore MD, Haines R, Anupam R. Mechanisms of human T-lymphotropic virus type 1 transmission and disease. Curr Opin Virol 2012; 2:474-81. [PMID: 22819021 DOI: 10.1016/j.coviro.2012.06.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 10/28/2022]
Abstract
Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15-20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3-5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma, or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis. The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as p30, p12, p13 and the antisense-encoded HTLV-1 basic leucine zipper factor (HBZ). While progress has been made in knowledge of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full-length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.
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Affiliation(s)
- Michael D Lairmore
- University of California-Davis, School of Veterinary Medicine, Davis, CA 95616, United States.
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Barrios CS, Abuerreish M, Lairmore MD, Castillo L, Giam CZ, Beilke MA. Recombinant human T-cell leukemia virus types 1 and 2 Tax proteins induce high levels of CC-chemokines and downregulate CCR5 in human peripheral blood mononuclear cells. Viral Immunol 2011; 24:429-39. [PMID: 22111594 DOI: 10.1089/vim.2011.0037] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human T-cell leukemia viruses types 1 (HTLV-1) and 2 (HTLV-2) produce key transcriptional regulatory gene products, known as Tax1 and Tax2, respectively. Tax1 and Tax2 transactivate multiple host genes involved in cellular immune responses within the cellular microenvironment, including induction of genes encoding expression of CC-chemokines. It is speculated that HTLV Tax proteins may act as immune modulators. In this study, recombinant Tax1 and Tax2 proteins were tested for their effects on the viability of cultured peripheral blood mononuclear cells (PBMCs), and their ability to induce expression of CC-chemokines and to downregulate the level of CCR5 expression in PBMCs. PBMCs obtained from uninfected donors were cultured in a range of Tax1 and Tax2 concentrations (10-100 pM), and supernatant fluids were harvested at multiple time points for quantitative determinations of MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5. Treatment of PBMCs with Tax1 and Tax2 proteins (100 pM) resulted in a significant increase in viability over a 7-d period compared to controls (p<0.01). Both Tax1 and Tax2 induced high levels of all three CC-chemokines over the dosing range compared to mock-treated controls (p<0.05). The gated population of lymphocytes treated with Tax2, as well as lymphocytes from HTLV-2-infected donors, showed a significantly lower percentage of CCR5-positive cells compared to those of uninfected donors and from mock-treated lymphocytes, respectively (p<0.05). These results suggest that Tax1 and Tax2 could promote innate immunity in the extracellular environment during HTLV-1 and HTLV-2 infections via CC-chemokine ligands and receptors.
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Affiliation(s)
- Christy S Barrios
- Infectious Diseases Division, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Martin F, Bangham CRM, Ciminale V, Lairmore MD, Murphy EL, Switzer WM, Mahieux R. Conference highlights of the 15th International Conference on Human Retrovirology: HTLV and related retroviruses, 4-8 June 2011, Leuven, Gembloux, Belgium. Retrovirology 2011; 8:86. [PMID: 22035054 PMCID: PMC3223150 DOI: 10.1186/1742-4690-8-86] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/28/2011] [Indexed: 12/27/2022] Open
Abstract
The June 2011 15th International Conference on Human Retrovirology: HTLV and Related Viruses marks approximately 30 years since the discovery of HTLV-1. As anticipated, a large number of abstracts were submitted and presented by scientists, new and old to the field of retrovirology, from all five continents. The aim of this review is to distribute the scientific highlights of the presentations as analysed and represented by experts in specific fields of epidemiology, clinical research, immunology, animal models, molecular and cellular biology, and virology.
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Affiliation(s)
- Fabiola Martin
- Centre for Immunology and Infection, Department of Biology, Hull and York Medical School, University of York, York, UK
| | - Charles RM Bangham
- Department of Immunology, Wright-Fleming Institute, Imperial College London, London, UK
| | - Vincenzo Ciminale
- Department of Oncology and Surgical Sciences and Istituto Oncologico Veneto-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Padova, Italy
| | - Michael D Lairmore
- Department of Veterinary Biosciences; Centre for Retrovirus Research; and Comprehensive Cancer Centre, The Arthur James Cancer Hospital and Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Edward L Murphy
- University of California San Francisco and Blood Systems Research Institute, San Francisco, California, USA
| | - William M Switzer
- Laboratory Branch, Division of HIV/AIDS Prevention, National Centre for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centres for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Renaud Mahieux
- Retroviral Oncogenesis Laboratory, INSERM-U758 Human Virology, 69364 Lyon cedex 07, France
- Ecole Normale Supérieure de Lyon, 69364 Lyon cedex 07, France
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Zimmerman B, Sargeant A, Landes K, Fernandez SA, Chen CS, Lairmore MD. Efficacy of novel histone deacetylase inhibitor, AR42, in a mouse model of, human T-lymphotropic virus type 1 adult T cell lymphoma. Leuk Res 2011; 35:1491-7. [PMID: 21802726 DOI: 10.1016/j.leukres.2011.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 06/25/2011] [Accepted: 07/09/2011] [Indexed: 12/27/2022]
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) causes a variety of forms of adult T-cell leukemia/lymphoma (ATL), a refractory CD4+/CD25+ T-cell malignancy. Novel approaches to treat ATL patients are required due to the resistance of ATL to conventional chemotherapies. Histone deacetylase inhibitors (HDACi), which induce histone hyperacetylation leading to chromatin remodeling and reactivation of transcriptionally repressed genes have shown efficacy against a variety of cancers. Herein, we tested if valproic acid and the novel orally bioavailable HDACi, AR-42 reduced the proliferation of ATL cell lines by promoting apoptosis and histone hyperacetylation. Both compounds were cytotoxic and elicited a dose dependent increase in cytochrome C and cleaved Poly (ADP-ribose) polymerase (PARP) indicating the induction of cell death by apoptosis and promoted acetylation of histone H3 in both MT-2 and C8166 cell lines. We then evaluated the effects of AR-42, for survival in an ATL NOD/SCID mouse model. A dietary formulation of AR-42 prolonged survival of ATL engrafted mice compared to controls. Our data provide new directions for the treatment of ATL and support the further development of AR-42 against HTLV-1-associated lymphoid malignancies.
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Affiliation(s)
- Bevin Zimmerman
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210-1093, USA
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Lairmore MD, Anupam R, Bowden N, Haines R, Haynes RAH, Ratner L, Green PL. Molecular determinants of human T-lymphotropic virus type 1 transmission and spread. Viruses 2011; 3:1131-65. [PMID: 21994774 PMCID: PMC3185783 DOI: 10.3390/v3071131] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/01/2011] [Accepted: 07/02/2011] [Indexed: 01/23/2023] Open
Abstract
Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15 to 20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells, most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3 to 5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma (ATL), or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as, p30, p12, p13 and the antisense encoded HBZ. While progress has been made in the understanding of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.
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Affiliation(s)
- Michael D. Lairmore
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-614-292-9203; Fax: +1-614-292-6473
| | - Rajaneesh Anupam
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Nadine Bowden
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Robyn Haines
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Rashade A. H. Haynes
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Division of Biology and Biological Sciences, Washington University School of Medicine, Campus Box 8069, 660 S. Euclid Ave., St. Louis, MO 63110, USA; E-Mail: (L.R.)
| | - Patrick L. Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Bolon B, Altrock B, Barthold SW, Baumgarth N, Besselsen D, Boivin G, Boyd KL, Brayton C, Cardiff RD, Couto S, Eaton KA, Foreman O, Griffey SM, La Perle K, Lairmore MD, Liu C, Meyerholz DK, Nikitin AY, Schoeb TR, Schwahn D, Sellers RS, Sundberg JP, Tolwani R, Valli VE, Zink MC. Advancing translational research. Science 2011; 331:1516-7. [PMID: 21436422 DOI: 10.1126/science.331.6024.1516-b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Anupam R, Datta A, Kesic M, Green-Church K, Shkriabai N, Kvaratskhelia M, Lairmore MD. Human T-lymphotropic virus type 1 p30 interacts with REGgamma and modulates ATM (ataxia telangiectasia mutated) to promote cell survival. J Biol Chem 2011; 286:7661-8. [PMID: 21216954 DOI: 10.1074/jbc.m110.176354] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is a causative agent of adult T cell leukemia/lymphoma and a variety of inflammatory disorders. HTLV-1 encodes a nuclear localizing protein, p30, that selectively alters viral and cellular gene expression, activates G(2)-M cell cycle checkpoints, and is essential for viral spread. Here, we used immunoprecipitation and affinity pulldown of ectopically expressed p30 coupled with mass spectrometry to identify cellular binding partners of p30. Our data indicate that p30 specifically binds to cellular ATM (ataxia telangiectasia mutated) and REGγ (a nuclear 20 S proteasome activator). Under conditions of genotoxic stress, p30 expression was associated with reduced levels of ATM and increased cell survival. Knockdown or overexpression of REGγ paralleled p30 expression, suggesting an unexpected enhancement of p30 expression in the presence of REGγ. Finally, size exclusion chromatography revealed the presence of p30 in a high molecular mass complex along with ATM and REGγ. On the basis of our findings, we propose that HTLV-1 p30 interacts with ATM and REGγ to increase viral spread by facilitating cell survival.
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Affiliation(s)
- Rajaneesh Anupam
- Center for Retrovirus Research, Ohio State University, Columbus, Ohio 43210, USA
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Rauch DA, Hurchla MA, Harding JC, Deng H, Shea LK, Eagleton MC, Niewiesk S, Lairmore MD, Piwnica-Worms D, Rosol TJ, Weber JD, Ratner L, Weilbaecher KN. The ARF tumor suppressor regulates bone remodeling and osteosarcoma development in mice. PLoS One 2010; 5:e15755. [PMID: 21209895 PMCID: PMC3012707 DOI: 10.1371/journal.pone.0015755] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 11/22/2010] [Indexed: 12/30/2022] Open
Abstract
The ARF tumor suppressor regulates p53 as well as basic developmental processes independent of p53, including osteoclast activation, by controlling ribosomal biogenesis. Here we provide evidence that ARF is a master regulator of bone remodeling and osteosarcoma (OS) development in mice. Arf-/- mice displayed increased osteoblast (OB) and osteoclast (OC) activity with a significant net increase in trabecular bone volume. The long bones of Arf-/- mice had increased expression of OB genes while Arf-/- OB showed enhanced differentiation in vitro. Mice transgenic for the Tax oncogene develop lymphocytic tumors with associated osteolytic lesions, while Tax+Arf-/- mice uniformly developed spontaneous OS by 7 months of age. Tax+Arf-/- tumors were well differentiated OS characterized by an abundance of new bone with OC recruitment, expressed OB markers and displayed intact levels of p53 mRNA and reduced Rb transcript levels. Cell lines established from OS recapitulated characteristics of the primary tumor, including the expression of mature OB markers and ability to form mineralized tumors when transplanted. Loss of heterozygosity in OS tumors arising in Tax+Arf+/- mice emphasized the necessity of ARF-loss in OS development. Hypothesizing that inhibition of ARF-regulated bone remodeling would repress development of OS, we demonstrated that treatment of Tax+Arf-/- mice with zoledronic acid, a bisphosphonate inhibitor of OC activity and repressor of bone turnover, prevented or delayed the onset of OS. These data describe a novel role for ARF as a regulator of bone remodeling through effects on both OB and OC. Finally, these data underscore the potential of targeting bone remodeling as adjuvant therapy or in patients with genetic predispositions to prevent the development of OS.
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Affiliation(s)
- Daniel A. Rauch
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Michelle A. Hurchla
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - John C. Harding
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Hongju Deng
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lauren K. Shea
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Mark C. Eagleton
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Stefan Niewiesk
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Michael D. Lairmore
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - David Piwnica-Worms
- Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Thomas J. Rosol
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Jason D. Weber
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lee Ratner
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Katherine N. Weilbaecher
- Division of Molecular Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Abstract
Human T-lymphotropic virus type-1 (HTLV-1), the first human retrovirus discovered, is the causative agent of adult T-cell leukemia/lymphoma (ATL) and a number of lymphocyte-mediated inflammatory conditions including HTLV-1-associated myelopathy/tropical spastic paraparesis. Development of animal models to study the pathogenesis of HTLV-1-associated diseases has been problematic. Mechanisms of early infection and cell-to-cell transmission can be studied in rabbits and nonhuman primates, but lesion development and reagents are limited in these species. The mouse provides a cost-effective, highly reproducible model in which to study factors related to lymphoma development and the preclinical efficacy of potential therapies against ATL. The ability to manipulate transgenic mice has provided important insight into viral genes responsible for lymphocyte transformation. Expansion of various strains of immunodeficient mice has accelerated the testing of drugs and targeted therapy against ATL. This review compares various mouse models to illustrate recent advances in the understanding of HTLV-1-associated ATL development and how improvements in these models are critical to the future development of targeted therapies against this aggressive T-cell lymphoma.
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Affiliation(s)
- B Zimmerman
- The Ohio State University, Department of Veterinary Biosciences, Goss Laboratory, 1925 Coffey Road, Columbus, Ohio 43210-1093, USA
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16
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Haynes RAH, Zimmerman B, Millward L, Ware E, Premanandan C, Yu L, Phipps AJ, Lairmore MD. Early spatial and temporal events of human T-lymphotropic virus type 1 spread following blood-borne transmission in a rabbit model of infection. J Virol 2010; 84:5124-30. [PMID: 20219918 PMCID: PMC2863820 DOI: 10.1128/jvi.01537-09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 02/13/2010] [Indexed: 01/13/2023] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell leukemia/lymphoma (ATL) and is associated with a variety of lymphocyte-mediated disorders. HTLV-1 transmission occurs by transmission of infected cells via breast-feeding by infected mothers, sexual intercourse, and contaminated blood products. The route of exposure and early virus replication events are believed to be key determinants of virus-associated spread, antiviral immune responses, and ultimately disease outcomes. The lack of knowledge of early events of HTLV-1 spread following blood-borne transmission of the virus in vivo hinders a more complete understanding of the immunopathogenesis of HTLV-1 infections. Herein, we have used an established animal model of HTLV-1 infection to study early spatial and temporal events of the viral infection. Twelve-week-old rabbits were injected intravenously with cell-associated HTLV-1 (ACH-transformed R49). Blood and tissues were collected at defined intervals throughout the study to test the early spread of the infection. Antibody and hematologic responses were monitored throughout the infection. HTLV-1 intracellular Tax and soluble p19 matrix were tested from ex vivo cultured lymphocytes. Proviral copy numbers were measured by real-time PCR from blood and tissue mononuclear leukocytes. Our data indicate that intravenous infection with cell-associated HTLV-1 targets lymphocytes located in both primary lymphoid and gut-associated lymphoid compartments. A transient lymphocytosis that correlated with peak virus detection parameters was observed by 1 week postinfection before returning to baseline levels. Our data support emerging evidence that HTLV-1 promotes lymphocyte proliferation preceding early viral spread in lymphoid compartments to establish and maintain persistent infection.
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Affiliation(s)
- Rashade A. H. Haynes
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Bevin Zimmerman
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Laurie Millward
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Evan Ware
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Christopher Premanandan
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Lianbo Yu
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Andrew J. Phipps
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Michael D. Lairmore
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
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17
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Haynes RAH, Phipps AJ, Yamamoto B, Green P, Lairmore MD. Development of a cytotoxic T-cell assay in rabbits to evaluate early immune response to human T-lymphotropic virus type 1 infection. Viral Immunol 2010; 22:397-405. [PMID: 19951176 DOI: 10.1089/vim.2009.0059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell lymphoma/leukemia (ATL) following a prolonged clinical incubation period, despite a robust adaptive immune response against the virus. Early immune responses that allow establishment of the infection are difficult to study without effective animal models. We have developed a cytotoxic T-lymphocyte (CTL) assay to monitor the early events of HTLV-1 infection in rabbits. Rabbit skin fibroblast cell lines were established by transformation with a plasmid expressing simian virus 40 (SV40) large T antigen and used as autochthonous targets (derived from same individual animal) to measure CTL activity against HTLV-1 infection in rabbits. Recombinant vaccinia virus (rVV) constructs expressing either HTLV-1 envelope surface unit (SU) glycoprotein 46 or Tax proteins were used to infect fibroblast targets in a (51)Cr-release CTL assay. Rabbits inoculated with Jurkat T cells or ACH.2 cells (expressing ACH HTLV-1 molecule clone) were monitored at 0, 2, 4, 6, 8, 13, 21, and 34 wk post-infection. ACH.2-inoculated rabbits were monitored serologically and for viral infected cells following ex vivo culture. Proviral load analysis indicated that rabbits with higher proviral loads had significant CTL activity against HTLV-1 SU as early as 2 wk post-infection, while both low- and high-proviral-load groups had minimal Tax-specific CTL activity throughout the study. This first development of a stringent assay to measure HTLV-1 SU and Tax-specific CTL assay in the rabbit model will enhance immunopathogenesis studies of HTLV-1 infection. Our data suggest that during the early weeks following infection, HTLV-1-specific CTL responses are primarily targeted against Env-SU.
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Affiliation(s)
- Rashade A H Haynes
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210-1093, USA
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18
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Premanandan C, Storozuk CA, Clay CD, Lairmore MD, Schlesinger LS, Phipps AJ. Complement protein C3 binding to Bacillus anthracis spores enhances phagocytosis by human macrophages. Microb Pathog 2009; 46:306-14. [DOI: 10.1016/j.micpath.2009.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 03/16/2009] [Accepted: 03/18/2009] [Indexed: 11/26/2022]
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Abstract
The number of veterinarians in the United States is inadequate to meet societal needs in biomedical research and public health. Areas of greatest need include translational medical research, veterinary pathology, laboratory-animal medicine, emerging infectious diseases, public health, academic medicine, and production-animal medicine. Veterinarians have unique skill sets that enable them to serve as leaders or members of interdisciplinary research teams involved in basic science and biomedical research with applications to animal or human health. There are too few graduate veterinarians to serve broad national needs in private practice; academia; local, state, and federal government agencies; and private industry. There are no easy solutions to the problem of increasing the number of veterinarians in biomedical research. Progress will require creativity, modification of priorities, broad-based communication, support from faculty and professional organizations, effective mentoring, education in research and alternative careers as part of the veterinary professional curriculum, and recognition of the value of research experience among professional schools' admissions committees. New resources should be identified to improve communication and education, professional and graduate student programs in biomedical research, and support to junior faculty. These actions are necessary for the profession to sustain its viability as an integral part of biomedical research.
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Affiliation(s)
- Thomas J Rosol
- College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
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20
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Hackanson B, Becker H, Berg T, Binder M, Dierks C, Duque-Afonso J, Lairmore MD, Schäfer HS, Schnitzler M, Zeiser R, Martens U, Mertelsmann R, Lübbert M. XXIII International Association for Comparative Research on Leukemia and Related Diseases Symposium: from molecular pathogenesis to targeted therapy in leukemia and solid tumors. Cancer Res 2008; 68:5512-8. [PMID: 18632600 DOI: 10.1158/0008-5472.can-07-6859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Björn Hackanson
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
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21
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Yamamoto B, Li M, Kesic M, Younis I, Lairmore MD, Green PL. Human T-cell leukemia virus type 2 post-transcriptional control protein p28 is required for viral infectivity and persistence in vivo. Retrovirology 2008; 5:38. [PMID: 18474092 PMCID: PMC2405800 DOI: 10.1186/1742-4690-5-38] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 05/12/2008] [Indexed: 11/30/2022] Open
Abstract
Background Human T-cell leukemia virus (HTLV) type 1 and type 2 are related but distinct pathogenic complex retroviruses. HTLV-1 is associated with adult T-cell leukemia and a variety of immune-mediated disorders including the chronic neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraparesis. In contrast, HTLV-2 displays distinct biological differences and is much less pathogenic, with only a few reported cases of leukemia and neurological disease associated with infection. In addition to the structural and enzymatic proteins, HTLV encodes regulatory (Tax and Rex) and accessory proteins. Tax and Rex positively regulate virus production and are critical for efficient viral replication and pathogenesis. Using an over-expression system approach, we recently reported that the accessory gene product of the HTLV-1 and HTLV-2 open reading frame (ORF) II (p30 and p28, respectively) acts as a negative regulator of both Tax and Rex by binding to and retaining their mRNA in the nucleus, leading to reduced protein expression and virion production. Further characterization revealed that p28 was distinct from p30 in that it was devoid of major transcriptional modulating activity, suggesting potentially divergent functions that may be responsible for the distinct pathobiologies of HTLV-1 and HTLV-2. Results In this study, we investigated the functional significance of p28 in HTLV-2 infection, proliferation, and immortaliztion of primary T-cells in culture, and viral survival in an infectious rabbit animal model. An HTLV-2 p28 knockout virus (HTLV-2Δp28) was generated and evaluated. Infectivity and immortalization capacity of HTLV-2Δp28 in vitro was indistinguishable from wild type HTLV-2. In contrast, we showed that viral replication was severely attenuated in rabbits inoculated with HTLV-2Δp28 and the mutant virus failed to establish persistent infection. Conclusion We provide direct evidence that p28 is dispensable for viral replication and cellular immortalization of primary T-lymphocytes in cell culture. However, our data indicate that p28 function is critical for viral survival in vivo. Our results are consistent with the hypothesis that p28 repression of Tax and Rex-mediated viral gene expression may facilitate survival of these cells by down-modulating overall viral gene expression.
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Affiliation(s)
- Brenda Yamamoto
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA.
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22
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Shu ST, Nadella MVP, Dirksen WP, Fernandez SA, Thudi NK, Werbeck JL, Lairmore MD, Rosol TJ. A novel bioluminescent mouse model and effective therapy for adult T-cell leukemia/lymphoma. Cancer Res 2008; 67:11859-66. [PMID: 18089816 DOI: 10.1158/0008-5472.can-07-1701] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adult T-cell /lymphomaleukemia (ATLL) is caused by human T-cell lymphotropic virus type 1 (HTLV-1). Approximately 80% of ATLL patients develop humoral hypercalcemia of malignancy (HHM), a life-threatening complication leading to a poor prognosis. Parathyroid hormone-related protein (PTHrP) and macrophage inflammatory protein-1 alpha (MIP-1 alpha) are important factors in the pathogenesis of HHM in ATLL and the expression of PTHrP can be activated by nuclear factor kappaB (NF-kappaB). NF-kappaB is constitutively activated in ATLL cells and is essential for leukemogenesis including transformation of lymphocytes infected by HTLV-1. Our goal was to evaluate the effects of NF-kappaB disruption by a proteasomal inhibitor (PS-341) and osteoclastic inhibition by zoledronic acid (Zol) on the development of ATLL and HHM using a novel bioluminescent mouse model. We found that PS-341 decreased cell viability, increased apoptosis, and down-regulated PTHrP expression in ATLL cells in vitro. To investigate the in vivo efficacy, nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice were xenografted with ATLL cells and treated with vehicle control, PS-341, Zol, or a combination of PS-341 and Zol. Bioluminescent imaging and tumor cell count showed a significant reduction in tumor burden in mice from all treatment groups. All treatments also significantly reduced the plasma calcium concentrations. Zol treatment increased trabecular bone volume and decreased osteoclast parameters. PS-341 reduced PTHrP and MIP-1 alpha expression in tumor cells in vivo. Our results indicate that both PS-341 and Zol are effective treatments for ATLL and HHM, which are refractory to conventional therapy.
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Affiliation(s)
- Sherry T Shu
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43214, USA
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23
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Datta A, Silverman L, Phipps AJ, Hiraragi H, Ratner L, Lairmore MD. Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival. Retrovirology 2007; 4:49. [PMID: 17634129 PMCID: PMC1937004 DOI: 10.1186/1742-4690-4-49] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 07/16/2007] [Indexed: 12/18/2022] Open
Abstract
Background Human T-lymphotropic virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation. Results Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C), had enhanced checkpoint kinase 1 (Chk1) serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1), diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes. Conclusion Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T-cell survival.
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Affiliation(s)
- Antara Datta
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Lee Silverman
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Drug Safety and Disposition, Millenium Pharmaceuticals, Inc., 45 Sidney Street, Cambridge, Massachusetts, USA
| | - Andrew J Phipps
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Hajime Hiraragi
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Genentech, Inc. MS68, 1 DNA Way, South San Francisco, California, USA
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael D Lairmore
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio, USA
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Lairmore MD, Oglesbee M, Weisbrode SE, Wellman M, Rosol T, Stromberg P. Developing and fostering a dynamic program for training in veterinary pathology and clinical pathology: veterinary students to post-graduate education. J Vet Med Educ 2007; 34:464-472. [PMID: 18287474 PMCID: PMC3057672 DOI: 10.3138/jvme.34.4.464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Recent reports project a deficiency of veterinary pathologists, indicating a need to train highly qualified veterinary pathologists, particularly in academic veterinary medicine. The need to provide high-quality research training for veterinary pathologists has been recognized by the veterinary pathology training program of the Ohio State University (OSU) since its inception. The OSU program incorporates elements of both residency training and graduate education into a unified program. This review illustrates the components and structure of the training program and reflects on future challenges in training veterinary pathologists. Key elements of the OSU program include an experienced faculty, dedicated staff, and high-quality students who have a sense of common mission. The program is supported through cultural and infrastructure support. Financial compensation, limited research funding, and attractive work environments, including work-life balance, will undoubtedly continue to be forces in the marketplace for veterinary pathologists. To remain competitive and to expand the ability to train veterinary pathologists with research skills, programs must support strong faculty members, provide appropriate infrastructure support, and seek active partnerships with private industry to expand program opportunities. Shortages of trained faculty may be partially resolved by regional cooperation to share faculty expertise or through the use of communications technology to bridge distances between programs. To foster continued interest in academic careers, training programs will need to continue to evolve and respond to trainees' needs while maintaining strong allegiances to high-quality pathology training. Work-life balance, collegial environments that foster a culture of respect for veterinary pathology, and continued efforts to reach out to veterinary students to provide opportunities to learn about the diverse careers offered in veterinary pathology will pay long-term dividends for the future of the profession.
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Affiliation(s)
- Michael D. Lairmore
- DVM, PhD, Dipl. ACVP (anatomic pathology), Dipl. ACVM (virology and immunology), is Professor and Chair, Department of Veterinary Biosciences, and Associate Director for Basic Sciences, Comprehensive Cancer Center, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093 USA
| | - Michael Oglesbee
- DVM, PhD, Dipl. ACVP (anatomic pathology), is Professor and Graduate Studies Chair, Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093 USA
| | - Steve E. Weisbrode
- VMD, PhD, Dipl. ACVP (anatomic pathology), is a professor in the Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093 USA. Dr. Weisbrode is a former president of the American College of Veterinary Pathologists
| | - Maxey Wellman
- DVM, PhD, Dipl. ACVP (clinical pathology), is an associate professor in the Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093 USA. Dr. Wellman is a former president of the American Society of Veterinary Clinical Pathologists
| | - Thomas Rosol
- DVM, PhD, Dipl. ACVP (anatomic pathology), is Professor and Dean, College of Veterinary Medicine and Department of Veterinary Biosciences, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1093 USA
| | - Paul Stromberg
- DVM, PhD, Dipl. ACVP (anatomic pathology), is a professorin the Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093 USA. Dr. Stromberg is the current president of the American College of Veterinary Pathologists
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25
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Michael B, Nair AM, Datta A, Hiraragi H, Ratner L, Lairmore MD. Histone acetyltransferase (HAT) activity of p300 modulates human T lymphotropic virus type 1 p30II-mediated repression of LTR transcriptional activity. Virology 2006; 354:225-39. [PMID: 16890266 PMCID: PMC3044896 DOI: 10.1016/j.virol.2006.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 02/22/2006] [Accepted: 07/05/2006] [Indexed: 01/28/2023]
Abstract
Human T-lymphotropic virus type-1 (HTLV-1) is a deltaretrovirus that causes adult T cell leukemia/lymphoma, and is implicated in a variety of lymphocyte-mediated inflammatory disorders. HTLV-1 provirus has regulatory and accessory genes in four pX open reading frames. HTLV-1 pX ORF-II encodes two proteins, p13II and p30II, which are incompletely defined in virus replication or pathogenesis. We have demonstrated that pX ORF-II mutations block virus replication in vivo and that ORF-II encoded p30II, a nuclear-localizing protein that binds with CREB-binding protein (CBP)/p300, represses CREB and Tax responsive element (TRE)-mediated transcription. Herein, we have identified p30II motifs important for p300 binding and in regulating TRE-mediated transcription in the absence and presence of HTLV-1 provirus. Within amino acids 100-179 of p30II, a region important for repression of LTR-mediated transcription, we identified a single lysine residue at amino acid 106 (K3) that significantly modulates the ability of p30II to repress TRE-mediated transcription. Exogenous p300, in a dose-responsive manner, reverses p30II-dependent repression of TRE-mediated transcription, in the absence or presence of the provirus, In contrast to wild type p300, p300 HAT mutants (defective in histone acetyltransferase activity) only partially rescued p30(II)-mediated LTR repression. Deacetylation by histone deacetylase-1 (HDAC-1) enhanced p30II-mediated LTR repression, while inhibition of deacetylation by trichostatin A decreases p30(II)-mediated LTR repression. Collectively, our data indicate that HTLV-1 p30II modulates viral gene expression in a cooperative manner with p300-mediated acetylation.
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Affiliation(s)
- Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Amrithraj M. Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Antara Datta
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Hajime Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael D. Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Corresponding author. Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA. Fax: +1 614 292 6473., (M.D. Lairmore)
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26
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Premanandan C, Lairmore MD, Fernandez S, Phipps AJ. Quantitative measurement of anthrax toxin receptor messenger RNA in primary mononuclear phagocytes. Microb Pathog 2006; 41:193-8. [PMID: 16854559 DOI: 10.1016/j.micpath.2006.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 05/22/2006] [Accepted: 05/23/2006] [Indexed: 11/28/2022]
Abstract
Two anthrax toxin receptors have been identified, tumor endothelial marker 8 (TEM8) and capillary morphogenesis protein 2 (CMG2). Both receptors have been shown to be capable of facilitating the entry of Bacillus anthracis exotoxins into the cytosol of susceptible cells. The levels of TEM8 and CMG2 RNA transcripts present in human primary macrophages derived from multiple unrelated donors and primary mouse macrophages have not been well described. In this communication, we examined the expression of mRNA transcripts of TEM8 and CMG2 in primary human and mouse macrophages and mouse tissues by standard and quantitative real-time RT-PCR. Our results indicate that CMG2 transcripts are preferentially expressed over TEM8 transcripts in primary human and mouse macrophages as compared to immortalized cell lines.
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Affiliation(s)
- Christopher Premanandan
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093, USA
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27
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Nair AM, Michael B, Datta A, Fernandez S, Lairmore MD. Calcium-dependent enhancement of transcription of p300 by human T-lymphotropic type 1 p12I. Virology 2006; 353:247-57. [PMID: 16843515 PMCID: PMC3044894 DOI: 10.1016/j.virol.2006.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 02/10/2006] [Accepted: 06/06/2006] [Indexed: 10/24/2022]
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) p12I localizes to the endoplasmic reticulum and Golgi causing sustained release of calcium, T cell activation, and enhanced expression of several calcium-regulated genes. In recent microarray studies, p300 mRNA was increased in T cells expressing p12I. The co-activator p300 is a key regulator of cellular and viral transcription; however, factors that influence its transcriptional regulation are less well studied. We hypothesized that the transcription of p300 is calcium dependent and that sustained low magnitude increases in intracellular calcium may enhance the transcription of p300. Herein, we report enhanced expression of p300 in T cells by p12I in a calcium-dependent, but calcineurin-independent manner. Sustained low magnitude calcium release induced by ionomycin in T cells was sufficient to increased mRNA and protein levels of p300 resulting in enhanced transcription from a p300-dependent promoter. Promoter analysis of the p300 gene was used to predict calcium-responsive transcription factor binding sites. Using mutant forms of p12I, we demonstrate that ER localization of the viral protein is required to increase p300. In addition, p12I reversed the repression of HTLV-1 LTR-driven transcription by HTLV-1 p30II, a p300-binding protein. HTLV-1 p12I-mediated enhancement of p300 expression represents a novel mechanism of regulation of cellular gene expression by viral proteins. By targeting a ubiquitous second messenger such as calcium, HTLV-1 p12I may regulate the expression of the cellular transcriptional co-activator p300 to modulate viral gene expression and promote lymphocyte survival.
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Affiliation(s)
- Amrithraj M. Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Antara Datta
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Soledad Fernandez
- The Center for Statistics, College of Mathematical and Physical Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Michael D. Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Corresponding author. Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA. Fax: +1 614 292 6473, (M.D. Lairmore)
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28
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Kim SJ, Nair AM, Fernandez S, Mathes L, Lairmore MD. Enhancement of LFA-1-mediated T cell adhesion by human T lymphotropic virus type 1 p12I1. J Immunol 2006; 176:5463-70. [PMID: 16622014 PMCID: PMC2668115 DOI: 10.4049/jimmunol.176.9.5463] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cell-to-cell transmission of retroviruses, such as human T lymphotropic virus type 1 (HTLV-1), is well documented, but the roles of viral regulatory or other nonstructural proteins in the modulation of T cell adhesion are incompletely understood. In this study we tested the role of the HTLV-1 accessory protein, p12(I), on LFA-1-mediated cell adhesion. p12(I) is critical for early HTLV-1 infection by causing the release of calcium from the endoplasmic reticulum to activate NFAT-mediated transcription. We tested the role of this novel viral protein in mediating LFA-1-dependent cell adhesion. Our data indicated that T cells expressing a mutant HTLV-1 provirus that does not produce p12(I) mRNA (ACH.p12(I)) exhibited reduced LFA-1-mediated adhesion compared with wild-type HTLV-1-expressing cells (ACH). Furthermore, the expression of p12(I) in Jurkat T cells using lentiviral vectors enhanced LFA-1-mediated cell adhesion, which was inhibited by the calcium chelator BAPTA-AM, the calcium channel blocker SK&F 96365, and calpeptin, an inhibitor of the calcium-dependent protease calpain. Similar to the intracellular calcium mobilizer, thapsigargin, the expression of p12(I) in Jurkat T cells induced cell surface clustering of LFA-1 without changing the level of integrin expression. Our data are the first to indicate that HTLV-1 p12(I), in addition to enhancing T cell activation, promotes cell-to-cell spread by inducing LFA-1 clustering on T cells via calcium-dependent signaling.
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Affiliation(s)
- Seung-jae Kim
- Center for Retrovirus Research and Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210
| | - Amrithraj M. Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210
| | | | - Lawrence Mathes
- Center for Retrovirus Research and Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210
- Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, OH 43210
| | - Michael D. Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210
- Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, OH 43210
- Address correspondence and reprint requests to Dr. Michael D. Lairmore, Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093. E-mail address:
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29
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Hiraragi H, Kim SJ, Phipps AJ, Silic-Benussi M, Ciminale V, Ratner L, Green PL, Lairmore MD. Human T-lymphotropic virus type 1 mitochondrion-localizing protein p13(II) is required for viral infectivity in vivo. J Virol 2006; 80:3469-76. [PMID: 16537614 PMCID: PMC1440407 DOI: 10.1128/jvi.80.7.3469-3476.2006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1), the etiological agent of adult T-cell leukemia, encodes unique regulatory and accessory proteins in the pX region of the provirus, including the open reading frame II product p13(II). p13(II) localizes to mitochondria, binds farnesyl pyrophosphate synthetase, an enzyme involved in posttranslational farnesylation of Ras, and alters Ras-dependent cell signaling and control of apoptosis. The role of p13(II) in virus infection in vivo remains undetermined. Herein, we analyzed the functional significance of p13(II) in HTLV-1 infection. We compared the infectivity of a human B-cell line that harbors an infectious molecular clone of HTLV-1 with a selective mutation that prevents the translation of p13(II) (729.ACH.p13) to the infectivity of a wild-type HTLV-1-expressing cell line (729.ACH). 729.ACH and 729.ACH.p13 producer lines had comparable infectivities for cultured rabbit peripheral blood mononuclear cells (PBMC), and the fidelity of the start codon mutation in ACH.p13 was maintained after PBMC passage. In contrast, zero of six rabbits inoculated with 729.ACH.p13 cells failed to establish viral infection, whereas six of six rabbits inoculated with wild-type HTLV-1-expressing cells (729.ACH) were infected as measured by antibody responses, proviral load, and HTLV-1 p19 matrix antigen production from ex vivo-cultured PBMC. Our data are the first to indicate that the HTLV-1 mitochondrion-localizing protein p13(II) has an essential biological role during the early phase of virus infection in vivo.
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MESH Headings
- Animals
- Antibodies, Viral/metabolism
- Blotting, Western
- Cell Line, Tumor
- Cells, Cultured
- Coculture Techniques
- Codon, Initiator
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Products, gag/blood
- Genome, Viral
- Geranyltranstransferase/physiology
- HTLV-I Infections/virology
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/immunology
- Human T-lymphotropic virus 1/pathogenicity
- Human T-lymphotropic virus 1/physiology
- Humans
- Leukocytes, Mononuclear/virology
- Mitochondria/enzymology
- Mutation
- Polymerase Chain Reaction
- Proviruses/genetics
- Proviruses/isolation & purification
- Rabbits
- Retroviridae Proteins, Oncogenic/blood
- Viral Load
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Hajime Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA
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30
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Yilmaz A, Fernandez S, Lairmore MD, Boris-Lawrie K. Coordinate enhancement of transgene transcription and translation in a lentiviral vector. Retrovirology 2006; 3:13. [PMID: 16480517 PMCID: PMC1388234 DOI: 10.1186/1742-4690-3-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Accepted: 02/15/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coordinate enhancement of transgene transcription and translation would be a potent approach to significantly improve protein output in a broad array of viral vectors and nonviral expression systems. Many vector transgenes are complementary DNA (cDNA). The lack of splicing can significantly reduce the efficiency of their translation. Some retroviruses contain a 5' terminal post-transcriptional control element (PCE) that facilitates translation of unspliced mRNA. Here we evaluated the potential for spleen necrosis virus PCE to stimulate protein production from HIV-1 based lentiviral vector by: 1) improving translation of the internal transgene transcript; and 2) functionally synergizing with a transcriptional enhancer to achieve coordinate increases in RNA synthesis and translation. RESULTS Derivatives of HIV-1 SIN self-inactivating lentiviral vector were created that contain PCE and cytomegalovirus immediate early enhancer (CMV IE). Results from transfected cells and four different transduced cell types indicate that: 1) PCE enhanced transgene protein synthesis; 2) transcription from the internal promoter is enhanced by CMV IE; 3) PCE and CMV IE functioned synergistically to significantly increase transgene protein yield; 4) the magnitude of translation enhancement by PCE was similar in transfected and transduced cells; 5) differences were observed in steady state level of PCE vector RNA in transfected and transduced cells; 6) the lower steady state was not attributable to reduced RNA stability, but to lower cytoplasmic accumulation in transduced cells. CONCLUSION PCE is a useful tool to improve post-transcriptional expression of lentiviral vector transgene. Coordinate enhancement of transcription and translation is conferred by the combination of PCE with CMV IE transcriptional enhancer and increased protein yield up to 11 to 17-fold in transfected cells. The incorporation of the vector provirus into chromatin correlated with reduced cytoplasmic accumulation of PCE transgene RNA. We speculate that epigenetic modulation of promoter activity altered cotranscriptional recruitment of RNA processing factors and reduced the availability of fully processed transcript or the efficiency of export from the nucleus. Our results provide an example of the dynamic interplay between the transcription and post-transcription steps of gene expression and document that introduction of heterologous gene expression signals can yield disparate effects in transfected versus transduced cells.
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Affiliation(s)
- Alper Yilmaz
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Soledad Fernandez
- Center for Biostatistics, The Ohio State University, Columbus, OH, 43210, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210, USA
| | - Michael D Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
- Department of Molecular Virology, Immunology & Medical Genetics, The Ohio State University, Columbus, OH, 43210, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Kathleen Boris-Lawrie
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
- Department of Molecular Virology, Immunology & Medical Genetics, The Ohio State University, Columbus, OH, 43210, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
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31
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Arnold J, Yamamoto B, Li M, Phipps AJ, Younis I, Lairmore MD, Green PL. Enhancement of infectivity and persistence in vivo by HBZ, a natural antisense coded protein of HTLV-1. Blood 2006; 107:3976-82. [PMID: 16424388 PMCID: PMC1895283 DOI: 10.1182/blood-2005-11-4551] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Natural antisense viral transcripts have been recognized in retroviruses, including human T-cell leukemia virus type 1 (HTLV-1), HIV-1, and feline immunodeficiency virus (FIV), and have been postulated to encode proteins important for the infection cycle and/or pathogenesis of the virus. The antisense strand of the HTLV-1 genome encodes HBZ, a novel nuclear basic region leucine zipper (b-ZIP) protein that in overexpression assays down-regulates Tax oncoprotein-induced viral transcription. Herein, we investigated the contribution of HBZ to HTLV-1-mediated immortalization of primary T lymphocytes in vitro and HTLV-1 infection in a rabbit animal model. HTLV-1 HBZ mutant viruses were generated and evaluated for viral gene expression, protein production, and immortalization capacity. Biologic properties of HBZ mutant viruses in vitro were indistinguishable from wild-type HTLV-1, providing the first direct evidence that HBZ is dispensable for viral replication and cellular immortalization. Rabbits inoculated with irradiated cells expressing HTLV-1 HBZ mutant viruses became persistently infected. However, these rabbits displayed a decreased antibody response to viral gene products and reduced proviral copies in peripheral blood mononuclear cells (PBMCs) as compared with wild-type HTLV-1-infected animals. Our findings indicated that HBZ was not required for in vitro cellular immortalization, but enhanced infectivity and persistence in inoculated rabbits. This study demonstrates that retroviruses use negative-strand-encoded proteins in the establishment of chronic viral infections.
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Affiliation(s)
- Joshua Arnold
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA
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32
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Silverman LR, Phipps AJ, Montgomery A, Fernandez S, Tsukahara T, Ratner L, Lairmore MD. In vivo analysis of replication and immunogenicity of proviral clones of human T-lymphotropic virus type 1 with selective envelope surface-unit mutations. Blood 2005; 106:3602-8. [PMID: 16046523 PMCID: PMC1895059 DOI: 10.1182/blood-2005-03-1076] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 07/20/2005] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell lymphoma/leukemia (ATL). The HTLV-1 envelope gene exhibits limited variability when examined from infected individuals, but has not been tested using infectious clones of the virus in animal models. In vitro assays indicate that HTLV-1 envelope (Env) Ser75Ile, Asn95Asp, and Asn195Asp surface unit (SU) mutants are able to replicate in and immortalize lymphocytes. Herein, we examined the effects of these Env mutants in rabbits inoculated with HTLV-1 immortalized ACH.75, ACH.95, or ACH.195 cell lines (expressing full-length molecular clones with the SU mutations) or the ACH.1 cell line (expressing wild-type SU). All rabbits became infected, and the fidelity of the mutations was maintained throughout the 8-week study. However, SU point mutations resulted in decreased antibody responses to viral group-associated antigen (Gag) and Env antigens. ACH.195 rabbits had a selective decreased antibody response to SU, and one ACH.195 rabbit had an antibody response to both HTLV-1 and HTLV-2 SUs. Some mutant inoculation groups had altered proviral loads. However, peripheral-blood mononuclear cell (PBMC) proviral loads did not correlate with antibody responses. Our data are the first to demonstrate that mutations in critical determinants of HTLV-1 Env SU altered antibody responses and proviral loads, but do not prevent viral replication in vivo.
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Affiliation(s)
- Lee R Silverman
- Center for Retrovirus Research and Department of Veterinary Biosciences, the Center for Biostatistics, The Ohio State University, Columbus, 43210, USA
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33
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Abstract
Over the past 25 years, animal models of human T-lymphotropic virus type 1 (HTLV-1) infection and transformation have provided critical knowledge about viral and host factors in adult T-cell leukemia/lymphoma (ATL). The virus consistently infects rabbits, some non-human primates, and to a lesser extent rats. In addition to providing fundamental concepts in viral transmission and immune responses against HTLV-1 infection, these models have provided new information about the role of viral proteins in carcinogenesis. Mice and rats, in particular immunodeficient strains, are useful models to assess immunologic parameters mediating tumor outgrowth and therapeutic invention strategies against lymphoma. Genetically altered mice including both transgenic and knockout mice offer important models to test the role of specific viral and host genes in the development of HTLV-1-associated lymphoma. Novel approaches in genetic manipulation of both HTLV-1 and animal models are available to address the complex questions that remain about viral-mediated mechanisms of cell transformation and disease. Current progress in the understanding of the molecular events of HTLV-1 infection and transformation suggests that answers to these questions are approachable using animal models of HTLV-1-associated lymphoma.
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Affiliation(s)
- Michael D Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210-1093, USA.
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34
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Abstract
The 12th International Conference on Human Retrovirology: HTLV and Related Retroviruses, was held at the Half Moon Hotel in Montego Bay, Jamaica, from June 22nd to June 25th 2005. The scientific conference, sponsored by the International Retrovirology Association, is held biennially at rotating international venues around the world. The meeting brings together basic scientists, epidemiologists and clinical researchers to discuss findings to prevent HTLV infection or develop new therapies against HTLV-mediated diseases. The Association fosters the education and training of young scientists to bring new approaches to the complex problems of HTLV research, such as translational research to bring findings from the laboratory into clinical trials that benefit HTLV-infected patients. The breadth and quality of research presentations and workshops at the 12th International Conference indicate that these goals are being accomplished. As HTLV research enters its third decade a new generation of scientists face many challenges. However, HTLV scientists and clinicians displayed exciting new approaches and discoveries during plenary talks and poster sessions. The conference encouraged research in HTLV infections and disease, fostered collaborations, and stimulated new partnerships between clinicians and scientists to encourage clinical trials and novel therapeutic interventions.
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Affiliation(s)
- Michael D Lairmore
- Department of Veterinary Biosciences and Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210 USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210 USA
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210 USA
| | - Masahiro Fujii
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences 1-757, Asahimachi-Dori Niigata, Niigata 951-8510 Japan
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35
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Richard V, Nadella MVP, Green PL, Lairmore MD, Feuer G, Foley JG, Rosol TJ. Transcriptional regulation of parathyroid hormone-related protein promoter P3 by ETS-1 in adult T-cell leukemia/lymphoma. Leukemia 2005; 19:1175-83. [PMID: 15889157 PMCID: PMC2661941 DOI: 10.1038/sj.leu.2403787] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) plays a primary role in the development of humoral hypercalcemia of malignancy seen in the majority of adult T-cell leukemia/lymphoma (ATLL) patients with human T-cell lymphotropic virus type-1 (HTLV-1) infection. HTLV-1 Tax has been shown to complex with ETS-1 and SP1 to transactivate the PTHrP P3 promoter. Previously, we established a SCID/bg mouse model of human ATL with RV-ATL cells and showed that PTHrP expression was independent of Tax. In this study, we report an inverse correlation of PTHrP with tax/rex mRNA in multiple HTLV-1-positive cell lines and RV-ATL cells. Stimulation of Jurkat T cells with PMA/ionomycin upregulated the PTHrP P3 promoter by a previously characterized Ets binding site and also induced protein/DNA complex formation identical to that observed in RV-ATL cells. Further, we provide evidence that cotransfection with Ets-1 and constitutively active Mek-1 in HTLV-1-negative transformed T cells with stimulation by PMA/ionomycin not only resulted in a robust induction of PTHrP P3 but also formed a complex with ETS-1/P3 EBS similar to that in ATLL cells. Our data demonstrate that transcriptional regulation of PTHrP in ATLL cells can be controlled by T-cell receptor signaling and the ETS and MAPK ERK pathway in a Tax-independent manner.
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MESH Headings
- Adult
- Animals
- Cell Line, Tumor
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Gene Products, rex/genetics
- Gene Products, rex/metabolism
- Gene Products, tax/genetics
- Gene Products, tax/metabolism
- HTLV-I Infections/metabolism
- HTLV-I Infections/virology
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/metabolism
- Humans
- Leukemia-Lymphoma, Adult T-Cell/genetics
- Leukemia-Lymphoma, Adult T-Cell/metabolism
- Leukemia-Lymphoma, Adult T-Cell/virology
- Male
- Mice
- Parathyroid Hormone-Related Protein/genetics
- Parathyroid Hormone-Related Protein/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Protein c-ets-1
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-ets
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Antigen, T-Cell/metabolism
- Signal Transduction/physiology
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
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Affiliation(s)
- V Richard
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
| | - MVP Nadella
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
| | - PL Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, USA
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, OH, USA
| | - MD Lairmore
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, USA
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, OH, USA
| | - G Feuer
- State University of New York Upstate Medical University, Syracuse, NY, USA
| | - JG Foley
- Medical Sciences, Indiana University School of Medicine, Bloomington, IN, USA
| | - TJ Rosol
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, USA
- Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, OH, USA
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36
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D’Agostino DM, Silic-Benussi M, Hiraragi H, Lairmore MD, Ciminale V. The human T-cell leukemia virus type 1 p13II protein: effects on mitochondrial function and cell growth. Cell Death Differ 2005; 12 Suppl 1:905-15. [PMID: 15761473 PMCID: PMC3057663 DOI: 10.1038/sj.cdd.4401576] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
p13(II) of human T-cell leukemia virus type 1 (HTLV-1) is an 87-amino-acid protein that is targeted to the inner mitochondrial membrane. p13(II) alters mitochondrial membrane permeability, producing a rapid, membrane potential-dependent influx of K(+). These changes result in increased mitochondrial matrix volume and fragmentation and may lead to depolarization and alterations in mitochondrial Ca(2+) uptake/retention capacity. At the cellular level, p13(II) has been found to interfere with cell proliferation and transformation and to promote apoptosis induced by ceramide and Fas ligand. Assays carried out in T cells (the major targets of HTLV-1 infection in vivo) demonstrate that p13(II)-mediated sensitization to Fas ligand-induced apoptosis can be blocked by an inhibitor of Ras farnesylation, thus implicating Ras signaling as a downstream target of p13(II) function.
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Affiliation(s)
- DM D’Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - M Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - H Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
| | - MD Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
- Comprehensive Cancer Center and Richard J. Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - V Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
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Altanerova V, Holicova D, Kucerova L, Altaner C, Lairmore MD, Boris-Lawrie K. Long-term infection with retroviral structural gene vector provides protection against bovine leukemia virus disease in rabbits. Virology 2005; 329:434-9. [PMID: 15518821 PMCID: PMC3049242 DOI: 10.1016/j.virol.2004.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 08/19/2004] [Accepted: 09/03/2004] [Indexed: 01/19/2023]
Abstract
Bovine leukemia virus (BLV) infection of rabbits is a tractable model system to evaluate vaccination strategies against lymphotropic retroviruses, which represent a global human health problem. We have previously developed genetically simplified BLV structural gene vector (SGV) that replicates BLV structural and enzymatic genes independently of BLV regulatory and accessory genes. Results of a 20-month study in a rabbit model demonstrated that BLV SGV induces an antiviral immunological response and lacks pathogenicity. Here, these chronically infected-BLV SGV rabbits are assessed in a proof-of-principle study of preventative vaccination against challenge with pathogenic BLV. This study commences 24 months after BLV SGV inoculation and proceeds for an additional 20 months. The previously characterized BLV SGV rabbits and age-matched control rabbits were challenged with 1 x 10(8) fetal lamb kidney/BLV producer cells. BLV SGV rabbits seroconverted upon BLV challenge, but did not progress to BLV infection nor clinical disease. By contrast, naive rabbits became infected and succumbed to lymphotropic disease. Our findings provide proof-of-principle that chronic infection with BLV SGV induces protection against BLV infection. The data indicate that SGV based on HTLV or HIV is a promising approach against lymphotropic disease by human retroviruses.
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Affiliation(s)
- Veronika Altanerova
- Cancer Research Institute, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
- Centre of Excellence of SAS Bratislava Molecular Medicine, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
| | - Dana Holicova
- Cancer Research Institute, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
| | - Lucia Kucerova
- Cancer Research Institute, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
| | - Cestmir Altaner
- Cancer Research Institute, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
- Centre of Excellence of SAS Bratislava Molecular Medicine, Slovak Academy of Sciences, SK-833 91 Bratislava, Slovakia
| | - Michael D. Lairmore
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210-1093, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210-1093, USA
- Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH, 43210-1093, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210-1093, USA
| | - Kathleen Boris-Lawrie
- Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210-1093, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210-1093, USA
- Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH, 43210-1093, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210-1093, USA
- Corresponding author. Center for Retrovirus Research, The Ohio State University, 1925 Coffey Road, Columbus, OH, 43210-1093. Fax: +1 614 292 6473.
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Lairmore MD, Montgomery A. Isolation and confirmation of human T-cell leukemia virus type 2 from peripheral blood mononuclear cells. Methods Mol Biol 2005; 304:113-23. [PMID: 16061970 PMCID: PMC3060566 DOI: 10.1385/1-59259-907-9:113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Human T-cell leukemia virus type 2 (HTLV-2) was first isolated from leukemia patients, but has been found to be endemic among asymptomatic groups worldwide, including certain American Indian tribes. The virus infection is associated with a low incidence of disease among infected subjects, but has been found in patients with neurologic disorders and contributes to bacterial sepsis in AIDS patients. Polymerase chain reaction (PCR) and virus isolation techniques revealed that a high percentage of HTLV seroreactivity among intravenous drug users and blood donors in the United States is caused by HTLV-2. Among serologic methods, enzyme-linked immunosorbent assays (ELISA) using whole virus preparations or in combination with recombinant and synthetic peptides are used as a primary screen for the infection. Antigen-capture systems have increased the sensitivity and accuracy in verification of HTLV-2 culture systems. The verification of HTLV-2 infection and detection of new strains of related viruses has been enhanced by employing virus-isolation methods using primary lymphocytes. Lymphocyte culture methods have also been used to test transformation properties of the virus and create stably expressing cell lines. This chapter briefly summarizes the biology of HTLV-2 infection and disease and details methods to isolate and verify the virus in lymphocyte cultures.
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Affiliation(s)
- Michael D Lairmore
- Center for Retrovirus Research, Department of Veterinary Biosciences, Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH, USA
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Abstract
The intentional use of Bacillus anthracis, the etiological agent of anthrax, as a bioterrorist weapon in late 2001 made our society acutely aware of the importance of developing, testing, and stockpiling adequate countermeasures against biological attacks. Biodefense vaccines are an important component of our arsenal to be used during a biological attack. However, most of the agents considered significant threats either have been eradicated or rarely infect humans alive today. As such, vaccine efficacy cannot be determined in human clinical trials but must be extrapolated from experimental animal models. This article reviews the efficacy and immunogenicity of human anthrax vaccines in well-defined animal models and the progress toward developing a rugged immunologic correlate of protection. The ongoing evaluation of human anthrax vaccines will be dependent on animal efficacy data in the absence of human efficacy data for licensure by the U.S. Food and Drug Administration.
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Affiliation(s)
- Andrew J Phipps
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210-1093, USA.
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Michael B, Nair AM, Hiraragi H, Shen L, Feuer G, Boris-Lawrie K, Lairmore MD. Human T lymphotropic virus type-1 p30II alters cellular gene expression to selectively enhance signaling pathways that activate T lymphocytes. Retrovirology 2004; 1:39. [PMID: 15560845 PMCID: PMC538277 DOI: 10.1186/1742-4690-1-39] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 11/23/2004] [Indexed: 11/13/2022] Open
Abstract
Background Human T-lymphotropic virus type-1 (HTLV-1) is a deltaretrovirus that causes adult T-cell leukemia/lymphoma and is implicated in a variety of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13II and p30II, which are incompletely defined in the virus life cycle or HTLV-1 pathogenesis. Proviral clones of the virus with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. Exogenous expression of p30II differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and represses tax/rex RNA nuclear export. Results Herein, we further characterized the role of p30II in regulation of cellular gene expression, using stable p30II expression system employing lentiviral vectors to test cellular gene expression with Affymetrix U133A arrays, representing ~33,000 human genes. Reporter assays in Jurkat T cells and RT-PCR in Jurkat and primary CD4+ T-lymphocytes were used to confirm selected gene expression patterns. Our data reveals alterations of interrelated pathways of cell proliferation, T-cell signaling, apoptosis and cell cycle in p30II expressing Jurkat T cells. In all categories, p30II appeared to be an overall repressor of cellular gene expression, while selectively increasing the expression of certain key regulatory genes. Conclusions We are the first to demonstrate that p30II, while repressing the expression of many genes, selectively activates key gene pathways involved in T-cell signaling/activation. Collectively, our data suggests that this complex retrovirus, associated with lymphoproliferative diseases, relies upon accessory gene products to modify cellular environment to promote clonal expansion of the virus genome and thus maintain proviral loads in vivo.
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Affiliation(s)
- Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Safety Assessment, Merck &Co., Inc. WP45-224, West Point PA 19486, USA
| | - Amrithraj M Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Safety Assessment, Merck &Co., Inc. WP45-224, West Point PA 19486, USA
| | - Hajime Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Lei Shen
- Department of Statistics, College of Mathematical and Physical Sciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Gerold Feuer
- Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA
| | - Kathleen Boris-Lawrie
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
| | - Michael D Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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Younis I, Khair L, Dundr M, Lairmore MD, Franchini G, Green PL. Repression of human T-cell leukemia virus type 1 and type 2 replication by a viral mRNA-encoded posttranscriptional regulator. J Virol 2004; 78:11077-83. [PMID: 15452228 PMCID: PMC521841 DOI: 10.1128/jvi.78.20.11077-11083.2004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2 are complex retroviruses that persist in the host, eventually causing leukemia and neurological disease in a small percentage of infected individuals. In addition to structural and enzymatic proteins, HTLV encodes regulatory (Tax and Rex) and accessory (open reading frame I and II) proteins. The viral Tax and Rex proteins positively regulate virus production. Tax activates viral and cellular transcription to promote T-cell growth and, ultimately, malignant transformation. Rex acts posttranscriptionally to facilitate cytoplasmic expression of viral mRNAs that encode the structural and enzymatic gene products, thus positively controlling virion expression. Here, we report that both HTLV-1 and HTLV-2 have evolved accessory genes to encode proteins that act as negative regulators of both Tax and Rex. HTLV-1 p30(II) and the related HTLV-2 p28(II) inhibit virion production by binding to and retaining tax/rex mRNA in the nucleus. Reduction of viral replication in a cell carrying the provirus may allow escape from immune recognition in an infected individual. These data are consistent with the critical role of these proteins in viral persistence and pathogenesis in animal models of HTLV-1 and HTLV-2 infection.
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Affiliation(s)
- Ihab Younis
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Rd., Columbus, OH 43210, USA
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Michael B, Nair A, Lairmore MD. Role of accessory proteins of HTLV-1 in viral replication, T cell activation, and cellular gene expression. FRONT BIOSCI-LANDMRK 2004; 9:2556-76. [PMID: 15358581 PMCID: PMC2829751 DOI: 10.2741/1417] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1), causes adult T cell leukemia/lymphoma (ATLL), and initiates a variety of immune mediated disorders. The viral genome encodes common structural and enzymatic proteins characteristic of all retroviruses and utilizes alternative splicing and alternate codon usage to make several regulatory and accessory proteins encoded in the pX region (pX ORF I to IV). Recent studies indicate that the accessory proteins p12I, p27I, p13II, and p30II, encoded by pX ORF I and II, contribute to viral replication and the ability of the virus to maintain typical in vivo expression levels. Proviral clones that are mutated in either pX ORF I or II, while fully competent in cell culture, are severely limited in their replicative capacity in a rabbit model. These HTLV-1 accessory proteins are critical for establishment of viral infectivity, enhance T-lymphocyte activation and potentially alter gene transcription and mitochondrial function. HTLV-1 pX ORF I expression is critical to the viral infectivity in resting primary lymphocytes suggesting a role for the calcineurin-binding protein p12I in lymphocyte activation. The endoplasmic reticulum and cis-Golgi localizing p12I activates NFAT, a key T cell transcription factor, through calcium-mediated signaling pathways and may lower the threshold of lymphocyte activation via the JAK/STAT pathway. In contrast p30II localizes to the nucleus and represses viral promoter activity, but may regulate cellular gene expression through p300/CBP or related co-activators of transcription. The mitochondrial localizing p13II induces morphologic changes in the organelle and may influence energy metabolism infected cells. Future studies of the molecular details HTLV-1 "accessory" proteins interactions will provide important new directions for investigations of HTLV-1 and related viruses associated with lymphoproliferative diseases. Thus, the accessory proteins of HTLV-1, once thought to be dispensable for viral replication, have proven to be directly involved in viral spread in vivo and represent potential targets for therapeutic intervention against HTLV-1 infection and disease.
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Affiliation(s)
- Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Amithraj Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Michael D. Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
- Corresponding Author: Dr. Michael D. Lairmore, The Ohio State University, Department of Veterinary Biosciences, 1925 Coffey Road, Columbus, OH 43210-1093, Phone: (614) 292-4489. Fax: (614) 292-6473.
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Silverman LR, Phipps AJ, Montgomery A, Ratner L, Lairmore MD. Human T-cell lymphotropic virus type 1 open reading frame II-encoded p30II is required for in vivo replication: evidence of in vivo reversion. J Virol 2004; 78:3837-45. [PMID: 15047799 PMCID: PMC374265 DOI: 10.1128/jvi.78.8.3837-3845.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma and exhibits high genetic stability in vivo. HTLV-1 contains four open reading frames (ORFs) in its pX region. ORF II encodes two proteins, p30(II) and p13(II), both of which are incompletely characterized. p30(II) localizes to the nucleus or nucleolus and has distant homology to the transcription factors Oct-1, Pit-1, and POU-M1. In vitro studies have demonstrated that at low concentrations, p30(II) differentially regulates cellular and viral promoters through an interaction with CREB binding protein/p300. To determine the in vivo significance of p30(II), we inoculated rabbits with cell lines expressing either a wild-type clone of HTLV-1 (ACH.1) or a clone containing a mutation in ORF II, which eliminated wild-type p30(II) expression (ACH.30.1). ACH.1-inoculated rabbits maintained higher HTLV-1-specific antibody titers than ACH.30.1-inoculated rabbits, and all ACH.1-inoculated rabbits were seropositive for HTLV-1, whereas only two of six ACH.30.1-inoculated rabbits were seropositive. Provirus could be consistently PCR amplified from peripheral blood mononuclear cell (PBMC) DNA in all ACH.1-inoculated rabbits but in only three of six ACH.30.1-inoculated rabbits. Quantitative competitive PCR indicated higher PBMC proviral loads in ACH.1-inoculated rabbits. Interestingly, sequencing of ORF II from PBMC of provirus-positive ACH.30.1-inoculated rabbits revealed a reversion to wild-type sequence with evidence of early coexistence of mutant and wild-type sequence. Our data provide evidence that HTLV-1 must maintain its key accessory genes to survive in vivo and that in vivo pressures select for maintenance of wild-type ORF II gene products during the early course of infection.
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Affiliation(s)
- Lee R Silverman
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
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Silic-Benussi M, Cavallari I, Zorzan T, Rossi E, Hiraragi H, Rosato A, Horie K, Saggioro D, Lairmore MD, Willems L, Chieco-Bianchi L, D'Agostino DM, Ciminale V. Suppression of tumor growth and cell proliferation by p13II, a mitochondrial protein of human T cell leukemia virus type 1. Proc Natl Acad Sci U S A 2004; 101:6629-34. [PMID: 15100416 PMCID: PMC404096 DOI: 10.1073/pnas.0305502101] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Human T cell leukemia virus type 1 encodes an "accessory" protein named p13(II) that is targeted to mitochondria and triggers a rapid flux of K(+) and Ca(2+) across the inner membrane. In this study, we investigated the effects of p13(II) on tumorigenicity in vivo and on cell growth in vitro. Results showed that p13(II) significantly reduced the incidence and growth rate of tumors arising from c-myc and Ha-ras-cotransfected rat embryo fibroblasts. Consistent with these findings, HeLa-derived cell lines stably expressing p13(II) exhibited markedly reduced tumorigenicity, as well as reduced proliferation at high density in vitro. Mixed culture assays revealed that the phenotype of the p13(II) cell lines was dominant over that of control lines and was mediated by a heat-labile soluble factor. The p13(II) cell lines exhibited an enhanced response to Ca(2+)-mediated stimuli, as measured by increased sensitivity to C2-ceramide-induced apoptosis and by cAMP-responsive element-binding protein (CREB) phosphorylation in response to histamine. p13(II)-expressing Jurkat T cells also exhibited reduced proliferation, suggesting that the protein might exert similar effects in T cells, the primary target of HTLV-1 infection. These findings provide clues into the function of p13(II) as a negative regulator of cell growth and underscore a link between mitochondria, Ca(2+) signaling, and tumorigenicity.
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Affiliation(s)
- Micol Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padua, Via Gattamelata 64, 35128 Padua, Italy
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Ye J, Silverman L, Lairmore MD, Green PL. HTLV-1 Rex is required for viral spread and persistence in vivo but is dispensable for cellular immortalization in vitro. Blood 2003; 102:3963-9. [PMID: 12907436 PMCID: PMC2852248 DOI: 10.1182/blood-2003-05-1490] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is associated with leukemia/lymphoma and neurologic disorders. Although the viral transcriptional activator Tax is the critical viral oncoprotein, Rex, which regulates the expression of the viral structural and enzymatic genes, is essential for efficient viral replication. Herein, we investigate the contribution of Rex in HTLV-1 immortalization of primary T cells in vitro and viral survival in an infectious rabbit animal model. A Rex-deficient HTLV-1 (HTLVRex-) was constructed and characterized for viral gene expression, protein production, and immortalization capacity. Cells transiently transfected with the HTLVRex- proviral clone produced low detectable levels of p19 Gag. 729HTLVRex- stable transfectants produced functional Tax, but undetectable levels of Rex or p19 Gag. Coculture of irradiated 729HTLVRex- cells with peripheral blood mononuclear cells (PBMCs) resulted in sustained interleukin-2 (IL-2)-dependent growth of primary T lymphocytes. These cells carried the HTLVRex- genome and expressed tax/rex mRNA but produced no detectable Rex or p19 Gag. Rabbits inoculated with irradiated 729HTLVRex- cells or 729HTLVRex- cells transiently transfected with a Rex cDNA expression plasmid failed to become persistently infected or mount a detectable antibody response to the viral gene products. Together, our results provide the first direct evidence that Rex and its function to modulate viral gene expression and virion production is not required for in vitro immortalization by HTLV-1. However, Rex is critical for efficient infection of cells and persistence in vivo.
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Affiliation(s)
- Jianxin Ye
- The Ohio State University, 1925 Coffey Rd, Columbus, OH 43210, USA
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46
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Affiliation(s)
- Donald Holzschu
- Department of Biological Sciences, Ohio University, Athens, Ohio 45701, USA.
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47
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Ding W, Kim SJ, Nair AM, Michael B, Boris-Lawrie K, Tripp A, Feuer G, Lairmore MD. Human T-cell lymphotropic virus type 1 p12I enhances interleukin-2 production during T-cell activation. J Virol 2003; 77:11027-39. [PMID: 14512551 PMCID: PMC225008 DOI: 10.1128/jvi.77.20.11027-11039.2003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2002] [Accepted: 07/15/2003] [Indexed: 11/20/2022] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATLL) and a variety of lymphoproliferative disorders. The early virus-cell interactions that determine a productive infection remain unclear. However, it is well recognized that T-cell activation is required for effective retroviral integration into the host cell genome and subsequent viral replication. The HTLV-1 pX open reading frame I encoding protein, p12(I), is critical for the virus to establish persistent infection in vivo and for infection in quiescent primary lymphocytes in vitro. p12(I) localizes in the endoplasmic reticulum (ER) and cis-Golgi apparatus, increases intracellular calcium and activates nuclear factor of activated T cells (NFAT)-mediated transcription. To clarify the function of p12(I), we tested the production of IL-2 from Jurkat T cells and peripheral blood mononuclear cells (PBMC) expressing p12(I). Lentiviral vector expressed p12(I) in Jurkat T cells enhanced interleukin-2 (IL-2) production in a calcium pathway-dependent manner during T-cell receptor (TCR) stimulation. Expression of p12(I) also induced higher NFAT-mediated reporter gene activities during TCR stimulation in Jurkat T cells. In contrast, p12 expression in PBMC elicited increased IL-2 production in the presence of phorbal ester stimulation, but not during TCR stimulation. Finally, the requirement of ER localization for p12(I)-mediated NFAT activation was demonstrated and two positive regions and two negative regions in p12(I) were identified for the activation of this transcription factor by using p12(I) truncation mutants. These results are the first to indicate that HTLV-1, an etiologic agent associated with lymphoproliferative diseases, uses a conserved accessory protein to induce T-cell activation, an antecedent to efficient viral infection.
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Affiliation(s)
- Wei Ding
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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Kim SJ, Ding W, Albrecht B, Green PL, Lairmore MD. A conserved calcineurin-binding motif in human T lymphotropic virus type 1 p12I functions to modulate nuclear factor of activated T cell activation. J Biol Chem 2003; 278:15550-7. [PMID: 12601010 DOI: 10.1074/jbc.m210210200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The PXIXIT calcineurin binding motif or highly related sequences are found in a variety of calcineurin-binding proteins in yeast, mammalian cells, and viruses. The accessory protein p12(I) encoded in the HTLV-1 pX ORF I promotes T cell activation during the early stages of HTLV-1 infection by activating nuclear factor of activated T cells (NFAT) through calcium release from the endoplasmic reticulum. We identified in p12(I), a conserved motif, which is highly homologous with the PXIXIT calcineurin-binding motif of NFAT. Both immunoprecipitation and calmodulin agarose bead pull-down assays indicated that wild type p12(I) and mutants of p12(I) that contained the motif-bound calcineurin. In addition, an alanine substitution p12(I) mutant (p12(I) AXAXAA) had greatly reduced binding affinity for calcineurin. We then tested whether p12(I) binding to calcineurin affected NFAT activity. p12(I) competed with NFAT for calcineurin binding in calmodulin bead pull-down experiments. Furthermore, the p12(I) AXAXAA mutant enhanced NFAT nuclear translocation compared with wild type p12(I) and increased NFAT transcriptional activity 2-fold greater than wild type p12(I). Similar to NFAT, endogenous calcineurin phosphatase activity was increased in Jurkat T cells expressing p12(I) independent of its calcineurin binding property. Thus, the reduced binding of p12(I) to calcineurin allows enhanced nuclear translocation and transcription mediated by NFAT. Herein, we are the first to identify a retroviral protein that binds calcineurin. Our data suggest that HTLV-1 p12(I) modulates NFAT activation to promote early virus infection of T lymphocytes, providing a novel mechanism for retrovirus-mediated cell activation.
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Affiliation(s)
- Seung-jae Kim
- Center for Retrovirus Research and Department of Veterinary Biosciences, Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093, USA
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Ding W, Albrecht B, Kelley RE, Muthusamy N, Kim SJ, Altschuld RA, Lairmore MD. Human T-cell lymphotropic virus type 1 p12(I) expression increases cytoplasmic calcium to enhance the activation of nuclear factor of activated T cells. J Virol 2002; 76:10374-82. [PMID: 12239314 PMCID: PMC136546 DOI: 10.1128/jvi.76.20.10374-10382.2002] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) establishes persistent infection and is associated with lymphoproliferative or neurodegenerative diseases. As a complex retrovirus, HTLV-1 contains typical structural and enzymatic genes, as well as regulatory and accessory genes encoded in the pX region. The early events necessary for HTLV-1 to establish infection in lymphocytes, its primary target cells, remain unresolved. Recent studies have demonstrated the importance of regulatory and accessory gene products in determining this virus-host interaction. Among these, pX open reading frame I, which encodes two proteins, p12(I) and p27(I), is required for establishing persistent infection in vivo and for infection in quiescent primary lymphocytes. In addition, p12(I) localizes in the endoplasmic reticulum (ER) and cis-Golgi apparatus and associates with a calcium binding protein, calreticulin. We recently reported that p12(I) expression induces the calcium-responsive T-cell transcription factor, nuclear factor of activated T cells (NFAT), in the presence of phorbol ester activation. Based on these studies, we hypothesize that p12(I) may modulate calcium release from the ER. Here, we report that p12(I) expression increases basal cytoplasmic calcium and concurrently diminishes calcium available for release from the ER stores. Overexpression of calreticulin, a calcium buffer protein, blocked p12(I)-mediated NFAT activation independently of its ability to bind p12(I). Chemical inhibition studies using inhibitors of inositol 1,4,5-triphosphate receptor and calcium release-activated calcium channels suggest that inositol 1,4,5-triphosphate receptor in the ER membrane and calcium release-activated calcium channels in the plasma membrane contribute to p12(I)-mediated NFAT activation. Collectively, our results are the first to demonstrate the role of p12(I) in elevating cytoplasmic calcium, an antecedent to T-cell activation, and further support the important role of this accessory protein in the early events of HTLV-1 infection.
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Affiliation(s)
- Wei Ding
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA
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Albrecht B, Lairmore MD. Critical role of human T-lymphotropic virus type 1 accessory proteins in viral replication and pathogenesis. Microbiol Mol Biol Rev 2002; 66:396-406, table of contents. [PMID: 12208996 PMCID: PMC120794 DOI: 10.1128/mmbr.66.3.396-406.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated with a diverse range of lymphoproliferative and neurodegenerative diseases, yet pathogenic mechanisms induced by the virus remain obscure. This complex retrovirus contains typical structural and enzymatic genes but also unique regulatory and accessory genes in four open reading frames (ORFs) of the pX region of the viral genome (pX ORFs I to IV). The regulatory proteins encoded by pX ORFs III and IV, Tax and Rex, respectively, have been extensively characterized. In contrast the contribution of the four accessory proteins p12(I), p27(I), p13(II), and p30(II), encoded by pX ORFs I and II, to viral replication and pathogenesis remained unclear. Proviral clones that are mutated in either pX ORF I or II, while fully competent in cell culture, are severely limited in their replicative capacity in a rabbit model. Emerging evidence indicates that the HTLV-1 accessory proteins are critical for establishment of viral infectivity, enhance T-lymphocyte activation, and potentially alter gene transcription and mitochondrial function. HTLV-1 pX ORF I expression is critical to the viral infectivity in resting primary lymphocytes, suggesting a role for p12(I) in lymphocyte activation. The endoplasmic reticulum and cis-Golgi localizing p12(I), encoded from pX ORF I, activates NFAT, a key T-cell transcription factor, through calcium-mediated signaling pathways and may lower the threshold of lymphocyte activation via the JAK/STAT pathway. In contrast p30(II) localizes to the nucleus and represses viral promoter activity, but may regulate cellular gene expression through p300/CBP or related coactivators of transcription. p13(II) targets mitochondrial proteins, where it alters the organelle morphology and may influence energy metabolism. Collectively, studies of the molecular functions of the HTLV-1 accessory proteins provide insight into strategies used by retroviruses that are associated with lymphoproliferative diseases.
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Affiliation(s)
- Björn Albrecht
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
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