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Shimizu Y. Progression of Carotid Intima-Media Thickness Partly Indicates the Prevention of Hypertension among Older Individuals in the General Population. Life (Basel) 2023; 13:1588. [PMID: 37511963 PMCID: PMC10381883 DOI: 10.3390/life13071588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/04/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Structural atherosclerosis, as evaluated by carotid intima-media thickness (CIMT), is reported to be positively associated with hypertension. However, angiogenesis, which plays an important role in the progression of structural atherosclerosis, prevents hypertension by reducing peripheral vascular resistance. These associations evoke a contradiction: characteristics associated with the progression of structural atherosclerosis, which is related to hypertension, might prevent hypertension. To clarify novel mechanisms underlying the association between structural atherosclerosis and hypertension, multifaceted analyses are necessary. We performed several epidemiological studies based on this concept. This study summarizes those epidemiological studies and adds some discussion. Studies focusing on circulating CD34-positive cells, single-nucleotide polymorphisms (SNPs) of vascular endothelial growth factor (VEGF), SNPs in BRACA1-associated protein (BRAP), platelets, human T-cell leukemia virus type 1 (HTLV-1), and SNPs in aldehyde dehydrogenase 2 (ALDH2) have shown that active endothelial repair, which leads to the progression of structural atherosclerosis, helps prevent hypertension. These associations indicate that the progression of structural atherosclerosis could act as a marker of angiogenesis, which reduces peripheral vascular resistance. In general, a positive association between structural atherosclerosis and hypertension has been reported. However, the progression of structural atherosclerosis could act as a marker of activity that prevents hypertension via reductions in peripheral vascular resistance.
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Affiliation(s)
- Yuji Shimizu
- Epidemiology Section, Division of Public Health, Osaka Institute of Public Health, Osaka 537-0025, Japan
- Department of General Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8501, Japan
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2
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Enose-Akahata Y, Ngouth N, Ohayon J, Mandel M, Chavin J, Turner TJ, Jacobson S. Effect of Teriflunomide on Cells From Patients With Human T-cell Lymphotropic Virus Type 1-Associated Neurologic Disease. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2021; 8:8/3/e986. [PMID: 33837058 PMCID: PMC8054963 DOI: 10.1212/nxi.0000000000000986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 02/12/2021] [Indexed: 02/05/2023]
Abstract
Objective To test the hypothesis that teriflunomide can reduce ex vivo spontaneous proliferation of peripheral blood mononuclear cells (PBMCs) from patients with human T-cell lymphotropic virus type 1 (HTLV-1)–associated myelopathy/tropical spastic paraparesis (HAM/TSP). Methods PBMCs from patients with HAM/TSP were cultured in the presence and absence of teriflunomide and assessed for cell viability, lymphocyte proliferation, activation markers, HTLV-1 tax and HTLV-1 hbz messenger ribonucleic acid (mRNA) expression, and HTLV-1 Tax protein expression. Results In culture, teriflunomide did not affect cell viability. A concentration-dependent reduction in spontaneous proliferation of PBMCs was observed with 25 μM (38.3% inhibition), 50 μM (65.8% inhibition), and 100 μM (90.7% inhibition) teriflunomide. The inhibitory effects of teriflunomide were detected in both CD8+ and CD4+ T-cell subsets, which are involved in the immune response to HTLV-1 infection and the pathogenesis of HAM/TSP. There was no significant change in HTLV-1 proviral load (PVL) or tax mRNA/Tax protein expression in these short-term cultures, but there was a significant reduction of HTLV-1 PVL due to inhibition of proliferation of CD4+ T cells obtained from a subset of patients with HAM/TSP. Conclusions These results suggest that teriflunomide inhibits abnormal T-cell proliferation associated with HTLV-1 infection and may have potential as a therapeutic option in patients with HAM/TSP.
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Affiliation(s)
- Yoshimi Enose-Akahata
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Nyater Ngouth
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Joan Ohayon
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Matt Mandel
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Jeffrey Chavin
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Timothy J Turner
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA
| | - Steven Jacobson
- From the Viral Immunology Section (Y.E.-A., N.N., S.J.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Joan Ohayon, Neuroimmunology Clinic (J.O.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Sanofi (M.M., J.C., T.J.T.), Cambridge, MA.
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Shimizu Y, Arima K, Noguchi Y, Kawashiri SY, Yamanashi H, Tamai M, Nagata Y, Maeda T. Possible mechanisms underlying the association between human T-cell leukemia virus type 1 (HTLV-1) and hypertension in elderly Japanese population. Environ Health Prev Med 2021; 26:17. [PMID: 33514303 PMCID: PMC7846982 DOI: 10.1186/s12199-021-00938-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 01/13/2021] [Indexed: 11/12/2022] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1) activates inflammatory cascades by activating the NF-κB pathway. The minor allele of single nucleotide polymorphism (SNP) in breast cancer suppressor BRCA1-associated protein (BRAP), which has a common etiology with HTLV-1 infection, has been reported to be positively associated with carotid atherosclerosis, but inversely associated with hypertension. Therefore, HTLV-1 infection may be inversely associated with hypertension by activating endothelial maintenance, including atherosclerosis. To clarify these associations, a cross-sectional study was conducted using 2989 Japanese individuals aged 60–99 years participating in a general health check-up. Methods Logistic regression models were used to clarify the association between HTLV-1 and hypertension. Platelet levels stratified analyses were also performed since platelet production, which plays a crucial role in endothelium maintenance, can be stimulated by activating the NF-κB pathway. Results HTLV-1 infection was found to be significantly inversely associated with hypertension, particularly in subjects with high platelet levels (≥ second tertiles of platelet levels); the fully adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were 0.75 (0.62, 0.92) for total and 0.64 (0.50, 0.82) for high platelet levels, respectively. Further analysis of the non-hypertensive subjects demonstrated that HTLV-1 infection was significantly positively associated with atherosclerosis in subjects with the highest tertile of platelet levels (2.11 [1.15, 3.86]) but not in subjects with low platelet levels (first and second tertiles of platelet level) (0.89 [0.57, 1.39]). Conclusion Asymptomatic HTLV-1 infection is inversely associated with hypertension, possibly by activating endothelial maintenance, including atherosclerosis progression.
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Affiliation(s)
- Yuji Shimizu
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan. .,Department of Cardiovascular Disease Prevention, Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan.
| | - Kazuhiko Arima
- Department of Public Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuko Noguchi
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan
| | - Shin-Ya Kawashiri
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan
| | - Hirotomo Yamanashi
- Department of General Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Mami Tamai
- Department of Island and Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yasuhiro Nagata
- Center for Comprehensive Community Care Education, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Takahiro Maeda
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan.,Department of General Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Island and Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Nozuma S, Kubota R, Jacobson S. Human T-lymphotropic virus type 1 (HTLV-1) and cellular immune response in HTLV-1-associated myelopathy/tropical spastic paraparesis. J Neurovirol 2020; 26:652-663. [PMID: 32705480 PMCID: PMC7532128 DOI: 10.1007/s13365-020-00881-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 03/29/2020] [Accepted: 07/06/2020] [Indexed: 12/18/2022]
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is associated with adult T cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is an inflammatory disease of the spinal cord and clinically characterized by progressive spastic paraparesis, urinary incontinence, and mild sensory disturbance. The interaction between the host immune response and HTLV-1-infected cells regulates the development of HAM/TSP. HTLV-1 preferentially infects CD4+ T cells and is maintained by proliferation of the infected T cells. HTLV-1-infected cells rarely express viral antigens in vivo; however, they easily express the antigens after short-term culture. Therefore, such virus-expressing cells may lead to activation and expansion of antigen-specific T cell responses. Infected T cells with HTLV-1 and HTLV-1-specific CD8+ cytotoxic T lymphocytes invade the central nervous system and produce various proinflammatory cytokines and chemokines, leading to neuronal damage and degeneration. Therefore, cellular immune responses to HTLV-1 have been considered to play important roles in disease development of HAM/TSP. Recent studies have clarified the viral strategy for persistence in the host through genetic and epigenetic changes by HTLV-1 and host immune responses including T cell function and differentiation. Newly developed animal models could provide the opportunity to uncover the precise pathogenesis and development of clinically effective treatment. Several molecular target drugs are undergoing clinical trials with promising efficacy. In this review, we summarize recent advances in the immunopathogenesis of HAM/TSP and discuss the perspectives of the research on this disease.
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MESH Headings
- Animals
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/virology
- Cell Proliferation/drug effects
- Cytokines/biosynthesis
- Cytokines/immunology
- Disease Models, Animal
- Host-Pathogen Interactions/immunology
- Human T-lymphotropic virus 1/drug effects
- Human T-lymphotropic virus 1/immunology
- Human T-lymphotropic virus 1/pathogenicity
- Humans
- Immunity, Cellular/drug effects
- Immunologic Factors/therapeutic use
- Leukemia-Lymphoma, Adult T-Cell/drug therapy
- Leukemia-Lymphoma, Adult T-Cell/immunology
- Leukemia-Lymphoma, Adult T-Cell/pathology
- Leukemia-Lymphoma, Adult T-Cell/virology
- Lymphocyte Activation/drug effects
- Neurons/drug effects
- Neurons/immunology
- Neurons/pathology
- Neurons/virology
- Neuroprotective Agents/therapeutic use
- Paraparesis, Tropical Spastic/drug therapy
- Paraparesis, Tropical Spastic/immunology
- Paraparesis, Tropical Spastic/pathology
- Paraparesis, Tropical Spastic/virology
- Spinal Cord/drug effects
- Spinal Cord/immunology
- Spinal Cord/virology
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/virology
- Urinary Incontinence/drug therapy
- Urinary Incontinence/immunology
- Urinary Incontinence/pathology
- Urinary Incontinence/virology
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Affiliation(s)
- Satoshi Nozuma
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Ryuji Kubota
- Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima, Japan
| | - Steven Jacobson
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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Shimizu Y, Yamanashi H, Kitamura M, Furugen R, Iwasaki T, Fukuda H, Hayashida H, Kawasaki K, Kiyoura K, Kawashiri SY, Saito T, Kawakami A, Maeda T. Association between human T cell leukemia virus type-1 (HTLV-1) infection and advanced periodontitis in relation to atherosclerosis among elderly Japanese: a cross-sectional study. Environ Health Prev Med 2019; 24:81. [PMID: 31883515 PMCID: PMC6935119 DOI: 10.1186/s12199-019-0836-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/05/2019] [Indexed: 12/13/2022] Open
Abstract
Background Human T cell leukemia virus type-1 (HTLV-1) stimulates inflammation activity. Our previous study revealed a positive association between asymptomatic HTLV-1 infection and advanced periodontitis among elderly Japanese individuals with low levels of hematopoietic activity (reflected by reticulocyte levels). Since low hematopoietic activity has been correlated with low-grade inflammation and low-grade inflammation is associated with atherosclerosis, the status of atherosclerosis could, in turn, determine the nature of this association. Methods To this end, a cross-sectional study of 907 elderly Japanese individuals (aged 60–99 years), who had participated in dental health check-up during the period 2016–2018, was conducted. Advanced periodontitis was defined as periodontal pocket ≥ 6.0 mm. Results Among the study population, 295 (32.5%) were found to have atherosclerosis defined as a carotid intima-media thickness (CIMT) of ≥ 1.1 mm. HTLV-1 infection was positively associated with advanced periodontitis in participants with atherosclerosis, but no significant associations were observed among the participants without atherosclerosis. The known risk factors’ (including reticulocyte and CIMT) adjusted odds ratio (OR) and 95% confidence interval (CI) of advanced periodontitis were OR 2.01 and 95% CI 1.06–3.81 for participants with atherosclerosis and OR 0.61 and 95% CI 0.34–1.12 for participants without atherosclerosis. Conclusion This study found a significant association between HTLV-1 infection and advanced periodontitis among elderly Japanese with atherosclerosis. However, this association is absent in individuals without atherosclerosis, suggesting that atherosclerosis might act as a determinant in the association between HTLV-1 infection and advanced periodontitis among elderly Japanese.
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Affiliation(s)
- Yuji Shimizu
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan. .,Department of Cardiovascular Disease Prevention, Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan.
| | - Hirotomo Yamanashi
- Department of General Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Masayasu Kitamura
- Department of Oral Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Reiko Furugen
- Department of Oral Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Takahiro Iwasaki
- Department of Community Oral Health, School of Dentistry, Asahi University, Gifu, Japan
| | - Hideki Fukuda
- Department of Oral Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hideaki Hayashida
- Department of Oral Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Koji Kawasaki
- Community Medical Network Center, Nagasaki University Hospital, Nagasaki, Japan
| | - Kairi Kiyoura
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan
| | - Shin-Ya Kawashiri
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan
| | - Toshiyuki Saito
- Department of Oral Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Atsushi Kawakami
- Department of Immunology and Rheumatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Takahiro Maeda
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki-shi, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan.,Department of General Medicine, Nagasaki University Hospital, Nagasaki, Japan.,Department of Island and Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Enose-Akahata Y, Jacobson S. Immunovirological markers in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Retrovirology 2019; 16:35. [PMID: 31783764 PMCID: PMC6884770 DOI: 10.1186/s12977-019-0499-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/23/2019] [Indexed: 02/06/2023] Open
Abstract
Human T cell lymphotropic virus 1 (HTLV-1) is a human retrovirus and infects approximately 10–20 million people worldwide. While the majority of infected people are asymptomatic carriers of HTLV-1, only 4% of infected people develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is a chronic, progressive, neurological disease which usually progresses slowly without remission, and is characterized by perivascular inflammatory infiltrates in chronic inflammatory lesions of the central nervous system (CNS), primarily affecting the spinal cord. A high HTLV-1 proviral load, high levels of antibodies against HTLV-1 antigens, and elevated concentration of proteins are detected in cerebrospinal fluid (CSF) of HAM/TSP patients. These chronically activated immune responses against HTLV-1 and infiltration of inflammatory cells including HTLV-1 infected cells into the CNS contribute to clinical disability and underlie the pathogenesis of HAM/TSP. Since the disease development of HAM/TSP mainly occurs in adults, with a mean age at onset of 40–50 years, it is important for HTLV-1-infected carriers and HAM/TSP patients to be monitored throughout the disease process. Recent advances in technologies and findings provide new insights to virological and immunological aspects in both the CNS as well as in peripheral blood. In this review, we focus on understanding the inflammatory milieu in the CNS and discuss the immunopathogenic process in HTLV-1-associated neurologic diseases.
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Affiliation(s)
- Yoshimi Enose-Akahata
- Viral Immunology Section, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, 9000 Rockville Pike, Building 10 Room 5C-103, Bethesda, MD, USA
| | - Steven Jacobson
- Viral Immunology Section, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, 9000 Rockville Pike, Building 10 Room 5C-103, Bethesda, MD, USA.
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Nozuma S, Jacobson S. Neuroimmunology of Human T-Lymphotropic Virus Type 1-Associated Myelopathy/Tropical Spastic Paraparesis. Front Microbiol 2019; 10:885. [PMID: 31105674 PMCID: PMC6492533 DOI: 10.3389/fmicb.2019.00885] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/05/2019] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is the etiologic agent of both adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is clinically characterized by chronic progressive spastic paraparesis, urinary incontinence, and mild sensory disturbance. Given its well-characterized clinical presentation and pathophysiology, which is similar to the progressive forms of multiple sclerosis (MS), HAM/TSP is an ideal system to better understand other neuroimmunological disorders such as MS. Since the discovery of HAM/TSP, large numbers of clinical, virological, molecular, and immunological studies have been published. The host-virus interaction and host immune response play an important role for the development with HAM/TSP. HTLV-1-infected circulating T-cells invade the central nervous system (CNS) and cause an immunopathogenic response against virus and possibly components of the CNS. Neural damage and subsequent degeneration can cause severe disability in patients with HAM/TSP. Little progress has been made in the discovery of objective biomarkers for grading stages and predicting progression of disease and the development of molecular targeted therapy based on the underlying pathological mechanisms. We review the recent understanding of immunopathological mechanism of HAM/TSP and discuss the unmet need for research on this disease.
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Affiliation(s)
- Satoshi Nozuma
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Steven Jacobson
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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Assil S, Futsch N, Décembre E, Alais S, Gessain A, Cosset FL, Mahieux R, Dreux M, Dutartre H. Sensing of cell-associated HTLV by plasmacytoid dendritic cells is regulated by dense β-galactoside glycosylation. PLoS Pathog 2019; 15:e1007589. [PMID: 30818370 PMCID: PMC6413949 DOI: 10.1371/journal.ppat.1007589] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 03/12/2019] [Accepted: 01/22/2019] [Indexed: 01/20/2023] Open
Abstract
Human T Lymphotropic virus (HTLV) infection can persist in individuals resulting, at least in part, from viral escape of the innate immunity, including inhibition of type I interferon response in infected T-cells. Plasmacytoid dendritic cells (pDCs) are known to bypass viral escape by their robust type I interferon production. Here, we demonstrated that pDCs produce type I interferons upon physical cell contact with HTLV-infected cells, yet pDC activation inversely correlates with the ability of the HTLV-producing cells to transmit infection. We show that pDCs sense surface associated-HTLV present with glycan-rich structure referred to as biofilm-like structure, which thus represents a newly described viral structure triggering the antiviral response by pDCs. Consistently, heparan sulfate proteoglycans and especially the cell surface pattern of terminal β-galactoside glycosylation, modulate the transmission of the immunostimulatory RNA to pDCs. Altogether, our results uncover a function of virus-containing cell surface-associated glycosylated structures in the activation of innate immunity.
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Affiliation(s)
- Sonia Assil
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Nicolas Futsch
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Elodie Décembre
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Sandrine Alais
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Antoine Gessain
- Epidémiologie et Physiopathologie des Virus Oncogènes, Institut Pasteur, Paris France
| | - François-Loïc Cosset
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Renaud Mahieux
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Marlène Dreux
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
- * E-mail: (MD); (HD)
| | - Hélène Dutartre
- CIRI–Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
- * E-mail: (MD); (HD)
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Enose-Akahata Y, Vellucci A, Jacobson S. Role of HTLV-1 Tax and HBZ in the Pathogenesis of HAM/TSP. Front Microbiol 2017; 8:2563. [PMID: 29312243 PMCID: PMC5742587 DOI: 10.3389/fmicb.2017.02563] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/11/2017] [Indexed: 01/25/2023] Open
Abstract
Human T cell lymphotropic virus type 1 (HTLV-1) infection can lead to development of adult T cell leukemia/lymphoma (ATL) or HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in a subset of infected subjects. Understanding the interaction between host and HTLV-1 and the molecular mechanisms associated with disease pathogenesis is critical for development efficient therapies. Two HTLV-1 genes, tax and HTLV-1 basic leucine zipper factor (HBZ), have been demonstrated to play important roles in HTLV-1 infectivity and the growth and survival of leukemic cells. Increased HTLV-1 Tax expression induces the expression of various cellular genes such as IL-2 and IL-15, which directly contributes to lymphocyte activation and immunopathogenesis in HAM/TSP patients. However, little is known about the molecular and cellular mechanism of HBZ in development of HAM/TSP. It has been reported that HBZ mRNA expression was detected in HAM/TSP patients higher than in asymptomatic carriers and correlated with proviral load and disease severity. Unlike HTLV-1 tax, HBZ escapes efficient anti-viral immune responses and therefore these reactivities are difficult to detect. Thus, it is important to focus on understanding the function and the role of HTLV-1 tax and HBZ in disease development of HAM/TSP and discuss the potential use of these HTLV-1 viral gene products as biomarkers and therapeutic targets for HAM/TSP.
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Affiliation(s)
- Yoshimi Enose-Akahata
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Ashley Vellucci
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Steven Jacobson
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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Visualization of HTLV-1-specific cytotoxic T lymphocytes in the spinal cords of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis. J Neuropathol Exp Neurol 2015; 74:2-14. [PMID: 25470342 PMCID: PMC4336315 DOI: 10.1097/nen.0000000000000141] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Activated human T-lymphotropic virus type-1 (HTLV-1)–specific CD8-positive cytotoxic T lymphocytes (CTLs) are markedly increased in the periphery of patients with HTLV-1–associated myelopathy/tropical spastic paraparesis (HAM/TSP), an HTLV-1–induced inflammatory disease of the CNS. Although virus-specific CTLs play a pivotal role to eliminate virus-infected cells, the potential role of HTLV-1–specific CTLs in the pathogenesis of HAM/TSP remains unclear. To address this issue, we evaluated the infiltration of HTLV-1–specific CTLs and the expression of HTLV-1 proteins in the spinal cords of 3 patients with HAM/TSP. Confocal laser scanning microscopy with our unique staining procedure made it possible to visualize HTLV-1–specific CTLs infiltrating the CNS of the HAM/TSP patients. The frequency of HTLV-1–specific CTLs was more than 20% of CD8-positive cells infiltrating the CNS. In addition, HTLV-1 proteins were detected in CD4-positive infiltrating T lymphocytes but not CNS resident cells. Although neurons were generally preserved, apoptotic oligodendrocytes were frequently in contact with CD8-positive cells; this likely resulted in demyelination. These findings suggest that the immune responses of the CTLs against HTLV-1–infected CD4-positive lymphocytes migrating into the CNS resulted in bystander neural damage.
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Separate cellular localizations of human T-lymphotropic virus 1 (HTLV-1) Env and glucose transporter type 1 (GLUT1) are required for HTLV-1 Env-mediated fusion and infection. J Virol 2014; 89:502-11. [PMID: 25339765 DOI: 10.1128/jvi.02686-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Interaction of the envelope glycoprotein (Env) of human T-lymphotropic virus 1 (HTLV-1) with the glucose transporter type 1 (GLUT1) expressed in target cells is essential for viral entry. This study found that the expression level of GLUT1 in virus-producing 293T cells was inversely correlated with HTLV-1 Env-mediated fusion activity and infectivity. Chimeric studies between GLUT1 and GLUT3 indicated that the extracellular loop 6 (ECL6) of GLUT1 is important for the inhibition of cell-cell fusion mediated by Env. When GLUT1 was translocated into the plasma membrane from intracellular storage sites by bafilomycin A1 (BFLA1) treatment in 293T cells, HTLV-1 Env-mediated cell fusion and infection also were inhibited without the overexpression of GLUT1, indicating that the localization of GLUT1 in intracellular compartments rather than in the plasma membrane is crucial for the fusion activity of HTLV-1 Env. Immunoprecipitation and laser scanning confocal microscopic analyses indicated that under normal conditions, HTLV-1 Env and GLUT1 do not colocalize or interact. BFLA1 treatment induced this colocalization and interaction, indicating that GLUT1 normally accumulates in intracellular compartments separate from that of Env. Western blot analyses of FLAG-tagged HTLV-1 Env in virus-producing cells and the incorporation of HTLV-1 Env in virus-like particles (VLPs) indicate that the processing of Env is inhibited by either overexpression of GLUT1 or BFLA1 treatment in virus-producing 293T cells. This inhibition probably is due to the interaction of the Env with GLUT1 in intracellular compartments. Taken together, separate intracellular localizations of GLUT1 and HTLV-1 Env are required for the fusion activity and infectivity of HTLV-1 Env. IMPORTANCE The deltaretrovirus HTLV-1 is a causative agent of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although HTLV-1 is a complex retrovirus that has accessory genes, no HTLV-1 gene product has yet been shown to regulate its receptor GLUT1 in virus-producing cells. In this study, we found that a large amount of GLUT1 or translocation of GLUT1 to the plasma membrane from intracellular compartments in virus-producing cells enhances the colocalization and interaction of GLUT1 with HTLV-1 Env, leading to the inhibition of cell fusion activity and infectivity. The results of our study suggest that GLUT1 normally accumulates in separate intracellular compartments from Env, which is indeed required for the proper processing of Env.
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Ikebuchi R, Konnai S, Okagawa T, Nishimori A, Nakahara A, Murata S, Ohashi K. Differences in cellular function and viral protein expression between IgMhigh and IgMlow B-cells in bovine leukemia virus-infected cattle. J Gen Virol 2014; 95:1832-1842. [PMID: 24814926 DOI: 10.1099/vir.0.065011-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bovine leukemia virus (BLV) induces abnormal B-cell proliferation and B-cell lymphoma in cattle, where the BLV provirus is integrated into the host genome. BLV-infected B-cells rarely express viral proteins in vivo, but short-term cultivation augments BLV expression in some, but not all, BLV-infected B-cells. This observation suggests that two subsets, i.e. BLV-silencing cells and BLV-expressing cells, are present among BLV-infected B-cells, although the mechanisms of viral expression have not been determined. In this study, we examined B-cell markers and viral antigen expression in B-cells from BLV-infected cattle to identify markers that may discriminate BLV-expressing cells from BLV-silencing cells. The proportions of IgM(high) B-cells were increased in blood lymphocytes from BLV-infected cattle. IgM(high) B-cells mainly expressed BLV antigens, whereas IgM(low) B-cells did not, although the provirus load was equivalent in both subsets. Several parameters were investigated in these two subsets to characterize their cellular behaviour. Real-time PCR and microarray analyses detected higher expression levels of some proto-oncogenes (e.g. Maf, Jun and Fos) in IgM(low) B-cells than those in IgM(high) B-cells. Moreover, lymphoma cells obtained from the lymph nodes of 14 BLV-infected cattle contained IgM(low) or IgM(-) B-cells but no IgM(high) B-cells. To our knowledge, this is the first study to demonstrate that IgM(high) B-cells mainly comprise BLV-expressing cells, whereas IgM(low) B-cells comprise a high proportion of BLV-silencing B-cells in BLV-infected cattle.
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Affiliation(s)
- Ryoyo Ikebuchi
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Satoru Konnai
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Tomohiro Okagawa
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Asami Nishimori
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ayako Nakahara
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Shiro Murata
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kazuhiko Ohashi
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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Andrade RG, Gonçalves PDC, Ribeiro MA, Romanelli LCF, Ribas JG, Torres EB, Carneiro-Proietti ABDF, Barbosa-Stancioli EF, Martins ML. Strong correlation between tax and HBZ mRNA expression in HAM/TSP patients: distinct markers for the neurologic disease. J Clin Virol 2012; 56:135-40. [PMID: 23127563 DOI: 10.1016/j.jcv.2012.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/10/2012] [Accepted: 10/10/2012] [Indexed: 11/17/2022]
Abstract
BACKGROUND HTLV-1 proviral load is a risk marker for HAM/TSP, but it is insufficient to determine the disease outcome. HTLV-1 Tax and HBZ proteins have been implicated in HAM/TSP pathogenesis in inducing cell proliferation and cytotoxic T lymphocytes response. OBJECTIVES To quantify the expression of tax and HBZ mRNA in asymptomatic carriers (AC) and HAM patients, and to investigate their association with HAM/TSP. STUDY DESIGN We quantified the expression of HTLV-1 tax and HBZ mRNA in 37 AC and 26 HAM patients classified according to proviral load as low (AC(L) and HAM(L): <1% infected cells) or high (AC(H) and HAM(H): >1%). RESULTS The AC(L) subgroup showed the lowest frequency of individuals expressing tax mRNA in comparison with AC(H), HAM(L) and HAM(H), and tax mRNA load normalized by proviral load was significantly lower in the AC(L). In turn, normalized HBZ mRNA expression was similar in all subgroups. Both tax and HBZ mRNA expression were moderately correlated with proviral load in AC (r=0.6, p<0.001) and were weaker in HAM (r=0.4, p<0.05). In contrast, the correlation between tax and HBZ mRNA load was moderate in AC (r=0.5, p=0.001) and was much stronger in HAM (r=0.8, p<0.001). In addition, HBZ mRNA load, but not tax, was significantly associated with motor disability in HAM patients (p=0.036). CONCLUSIONS The expression of tax mRNA seems to be best to estimate the risk of HAM/TSP, whereas HBZ mRNA appears to be a surrogate marker to disease progression, indicating that they have important but distinct roles in HAM/TSP pathogenesis.
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Affiliation(s)
- Rafaela Gomes Andrade
- Microbiology Department, Biology Science Institute, Federal University of Minas Gerais, Brazil.
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Moens B, Decanine D, Menezes SM, Khouri R, Silva-Santos G, Lopez G, Alvarez C, Talledo M, Gotuzzo E, de Almeida Kruschewsky R, Galvão-Castro B, Vandamme AM, Van Weyenbergh J. Ascorbic acid has superior ex vivo antiproliferative, cell death-inducing and immunomodulatory effects over IFN-α in HTLV-1-associated myelopathy. PLoS Negl Trop Dis 2012; 6:e1729. [PMID: 22848768 PMCID: PMC3404116 DOI: 10.1371/journal.pntd.0001729] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 05/30/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Clear therapeutic guidelines for HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are missing due to the lack of randomized double-blind controlled clinical trials. Moderate yet similar clinical benefit has been demonstrated for IFN-α and high-dose ascorbic acid (AA) monotherapy in a large open clinical trial. However, there is a lack of in vivo and in vitro studies exploring and comparing the effects of high-dose AA and IFN-α treatment in the context of HAM/TSP. Therefore, we performed the first comparative analysis of the ex vivo and in vitro molecular and cellular mechanisms of action of IFN-α and high-dose AA in HAM/TSP. PRINCIPAL FINDINGS Through thymidine incorporation and quantification of Th1/Th2/Th17 cytokines, we demonstrate that high-dose AA displays differential and superior antiproliferative and immunomodulatory effects over IFN-α in HAM/TSP PBMCs ex vivo. In addition, high-dose AA, but not IFN-α, induced cell death in both HAM/TSP PBMCs and HTLV-1-infected T-cell lines MT-2 and MT-4. Microarray data combined with pathway analysis of MT-2 cells revealed AA-induced regulation of genes associated with cell death, including miR-155. Since miR-155 has recently been demonstrated to up-regulate IFN-γ, this microRNA might represent a novel therapeutic target in HAM/TSP, as recently demonstrated in multiple sclerosis, another neuroinflammatory disease. On the other hand, IFN-α selectively up-regulated antiviral and immune-related genes. CONCLUSIONS In comparison to IFN-α, high-dose AA treatment has superior ex vivo and in vitro cell death-inducing, antiproliferative and immunomodulatory anti-HTLV-1 effects. Differential pathway activation by both drugs opens up avenues for targeted treatment in specific patient subsets.
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Affiliation(s)
- Britta Moens
- Rega Institute for Medical Research, K. U. Leuven, Leuven, Belgium.
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15
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Hoshino H. Cellular Factors Involved in HTLV-1 Entry and Pathogenicit. Front Microbiol 2012; 3:222. [PMID: 22737146 PMCID: PMC3380293 DOI: 10.3389/fmicb.2012.00222] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 05/30/2012] [Indexed: 01/13/2023] Open
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T cell leukemia (ATL) and HTLV-1 – associated myelopathy and tropical spastic paraparesis (HAM/TSP). HTLV-1 has a preferential tropism for CD4 T cells in healthy carriers and ATL patients, while both CD4 and CD8 T cells serve as viral reservoirs in HAM/TSP patients. HTLV-1 has also been detected other cell types, including monocytes, endothelial cells, and dendritic cells. In contrast to the limited cell tropism of HTLV-1 in vivo, the HTLV receptor appears to be expressed in almost all human or animal cell lines. It remains to be examined whether this cell tropism is determined by host factors or by HTLV-1 heterogeneity. Unlike most retroviruses, cell-free virions of HTLV-1 are very poorly infectious. The lack of completely HTLV-1-resistant cells and the low infectivity of HTLV-1 have hampered research on the HTLV entry receptor. Entry of HTLV-1 into target cells is thought to involve interactions between the env (Env) glycoproteins, a surface glycoprotein (surface unit), and a transmembrane glycoprotein. Recent studies have shown that glucose transporter GLUT1, heparan sulfate proteoglycans (HSPGs), and neuropilin-1 (NRP-1) are the three proteins important for the entry of HTLV-1. Studies using adherent cell lines have shown that GLUT1 can function as a receptor for HTLV. HSPGs are required for efficient entry of HTLV-1 into primary CD4 T cells. NRP-1 is expressed in most established cell lines. Further studies have shown that these three molecules work together to promote HTLV-1 binding to cells and fusion of viral and cell membranes. The virus could first contact with HSPGs and then form complexes with NRP-1, followed by association with GLUT1. It remains to be determined whether these three molecules can explain HTLV-1 cell tropism. It also remains to be more definitively proven that these molecules are sufficient to permit HTLV-1 entry into completely HTLV-1-resistant cells.
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Affiliation(s)
- Hiroo Hoshino
- Advanced Scientific Research-Leaders Development Unit, Gunma University Graduate School of Medicine Maebashi, Gunma, Japan
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Kuo CWS, Mirsaliotis A, Brighty DW. Antibodies to the envelope glycoprotein of human T cell leukemia virus type 1 robustly activate cell-mediated cytotoxic responses and directly neutralize viral infectivity at multiple steps of the entry process. THE JOURNAL OF IMMUNOLOGY 2011; 187:361-71. [PMID: 21646298 DOI: 10.4049/jimmunol.1100070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Infection of human cells by human T cell leukemia virus type 1 (HTLV-1) is mediated by the viral envelope glycoproteins. The gp46 surface glycoprotein binds to cell surface receptors, including heparan sulfate proteoglycans, neuropilin 1, and glucose transporter 1, allowing the transmembrane glycoprotein to initiate fusion of the viral and cellular membranes. The envelope glycoproteins are recognized by neutralizing Abs and CTL following a protective immune response, and therefore, represent attractive components for a HTLV-1 vaccine. To begin to explore the immunological properties of potential envelope-based subunit vaccine candidates, we have used a soluble recombinant surface glycoprotein (gp46, SU) fused to the Fc region of human IgG (sRgp46-Fc) as an immunogen to vaccinate mice. The recombinant SU protein is highly immunogenic and induces high titer Ab responses, facilitating selection of hybridomas that secrete mAbs targeting SU. Many of these mAbs recognize envelope displayed on the surface of HTLV-1-infected cells and virions and several of the mAbs robustly antagonize envelope-mediated membrane fusion and neutralize pseudovirus infectivity. The most potently neutralizing mAbs recognize the N-terminal receptor-binding domain of SU, though there is considerable variation in neutralizing proficiency of the receptor-binding domain-targeted mAbs. By contrast, Abs targeting the C-terminal domain of SU tend to lack robust neutralizing activity. Importantly, we find that both neutralizing and poorly neutralizing Abs strongly stimulate neutrophil-mediated cytotoxic responses to HTLV-1-infected cells. Our data demonstrate that recombinant forms of SU possess immunological features that are of significant utility to subunit vaccine design.
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Affiliation(s)
- Chien-Wen S Kuo
- Biomedical Research Institute, College of Medicine Dentistry and Nursing, Ninewells Hospital, The University of Dundee, Dundee DD1 9SY, Scotland
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Hilburn S, Rowan A, Demontis MA, MacNamara A, Asquith B, Bangham CRM, Taylor GP. In vivo expression of human T-lymphotropic virus type 1 basic leucine-zipper protein generates specific CD8+ and CD4+ T-lymphocyte responses that correlate with clinical outcome. J Infect Dis 2011; 203:529-36. [PMID: 21208912 DOI: 10.1093/infdis/jiq078] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The roles of the human T-lymphotropic virus type 1 (HTLV-1) basic leucine zipper (HBZ) gene are not clearly understood. We examined CD8+ and CD4+ T cell responses to HBZ and compared these with Tax responses. METHOD Interferon (IFN)-γ and interleukin (IL)-2-secreting T cells were detected by enzyme-linked immunosorbent spot (ELISpot) assays of freshly isolated peripheral blood mononuclear cells (PBMCs) stimulated with synthetic HBZ or Tax peptides. Ten patients with HTLV-1-associated myelopathy (HAM) and 20 asymptomatic HTLV-1 carriers (ACs), (10 high, 10 low viral load). RESULTS Of 30 study participants, 17 had detectable HBZ-specific CD4+ T cells and 12 had HBZ-specific CD8+ T cell responses. Detection of Tax-specific CD4+ T cells (IL-2- or IFN-γ-secreting) did not differ by disease status, but Tax-specific CD8+ T cell responses were more commonly detected in patients with HAM. HBZ-specific CD4+ or CD8+ T cells were less likely to be detected than Tax-specific T cells. IL-2-secreting Tax-specific CD8+ T cells, and IFN-γ-secreting Tax-specific CD4+ T cells were associated with HAM. Low viral load, asymptomatic HTLV-1 carriage was associated with IL-2-secreting CD8+ T cells specific for HBZ. CONCLUSION HBZ protein is expressed in vivo in patients with HAM and in ACs. Our results are consistent with the idea that the T cell response to HBZ plays an important part in restricting HTLV-1 viral load.
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Affiliation(s)
- Silva Hilburn
- Infectious Diseases, Faculty of Medicine, Imperial College, Norfolk Place, London, England
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Zane L, Sibon D, Legras C, Lachuer J, Wierinckx A, Mehlen P, Delfau-Larue MH, Gessain A, Gout O, Pinatel C, Lançon A, Mortreux F, Wattel E. Clonal expansion of HTLV-1 positive CD8+ cells relies on cIAP-2 but not on c-FLIP expression. Virology 2010; 407:341-51. [DOI: 10.1016/j.virol.2010.07.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 05/11/2010] [Accepted: 07/16/2010] [Indexed: 10/19/2022]
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The HTLV-1 Virological Synapse. Viruses 2010; 2:1427-1447. [PMID: 21994688 PMCID: PMC3185711 DOI: 10.3390/v2071427] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/04/2010] [Accepted: 06/29/2010] [Indexed: 01/05/2023] Open
Abstract
Human T-lymphotropic virus-1 (HTLV-1) spreads efficiently between T-cells via a tight and highly organized cell-cell contact known as the virological synapse. It is now thought that many retroviruses and other viruses spread via a virological synapse, which may be defined as a virus-induced, specialized area of cell-to-cell contact that promotes the directed transmission of the virus between cells. We summarize here the mechanisms leading to the formation of the HTLV-1 virological synapse and the role played by HTLV-1 Tax protein. We propose a model of HTLV-1 transmission between T-cells based on the three-dimensional ultrastructure of the virological synapse. Finally, in the light of recent advances, we discuss the possible routes of HTLV-1 spread across the virological synapse.
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Lamb D, Mirsaliotis A, Kelly SM, Brighty DW. Basic residues are critical to the activity of peptide inhibitors of human T cell leukemia virus type 1 entry. J Biol Chem 2008; 284:6575-84. [PMID: 19114713 DOI: 10.1074/jbc.m806725200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A synthetic peptide based on the leash and alpha-helical region (LHR) of human T cell leukemia virus type 1 envelope is a potent inhibitor of viral entry into cells. The inhibitory peptide targets a triple-stranded coiled-coil motif of the fusion-active transmembrane glycoprotein and in a trans-dominant negative manner blocks resolution to the trimer-of-hairpins form. The LHR-mimetic is, therefore, functionally analogous to the C34/T20-type inhibitors of human immunodeficiency virus. Previous attempts to shorten the bioactive peptide produced peptides with severely attenuated activity. We now demonstrate that truncated peptides often suffer from poor solubility and impaired coiled coil binding properties, and we identify features that are critical to peptide function. In particular, the alpha-helical region of the LHR-mimetic is necessary but not sufficient for inhibitory activity. Moreover, two basic residues are crucial for coiled-coil binding and efficient inhibition of membrane fusion. By retaining these basic residues and a region of main chain peptide contacts with the coiled coil, a core LHR-mimetic was obtained that retains both the inhibitory properties and solubility profile of the parental peptide. Variants of the core peptide inhibit both membrane fusion and infection of cells by free viral particles, but unexpectedly, infection by virions was more susceptible to inhibition by low activity inhibitors than syncytium formation. The core inhibitor provides a valuable lead in the search for smaller more bio-available peptides and peptido-mimetics that possess anti-viral activity. Such molecules may be attractive candidates for therapeutic intervention in human T cell leukemia virus type 1 infections.
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Affiliation(s)
- Daniel Lamb
- Biomedical Research Centre, Ninewells Hospital and Medical School, The University, Dundee DD1 9SY, Scotland, United Kingdom
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Nonhelical leash and alpha-helical structures determine the potency of a peptide antagonist of human T-cell leukemia virus entry. J Virol 2008; 82:4965-73. [PMID: 18305034 DOI: 10.1128/jvi.02458-07] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral fusion proteins mediate the entry of enveloped viral particles into cells by inducing fusion of the viral and target cell membranes. Activated fusion proteins undergo a cascade of conformational transitions and ultimately resolve into a compact trimer of hairpins or six-helix bundle structure, which pulls the interacting membranes together to promote lipid mixing. Significantly, synthetic peptides based on a C-terminal region of the trimer of hairpins are potent inhibitors of membrane fusion and viral entry, and such peptides are typically extensively alpha-helical. In contrast, an atypical peptide inhibitor of human T-cell leukemia virus (HTLV) includes alpha-helical and nonhelical leash segments. We demonstrate that both the C helix and C-terminal leash are critical to the inhibitory activities of these peptides. Amino acid side chains in the leash and C helix extend into deep hydrophobic pockets at the membrane-proximal end of the HTLV type 1 (HTLV-1) coiled coil, and these contacts are necessary for potent antagonism of membrane fusion. In addition, a single amino acid substitution within the inhibitory peptide improves peptide interaction with the core coiled coil and yields a peptide with enhanced potency. We suggest that the deep pockets on the coiled coil are ideal targets for small-molecule inhibitors of HTLV-1 entry into cells. Moreover, the extended nature of the HTLV-1-inhibitory peptide suggests that such peptides may be intrinsically amenable to modifications designed to improve inhibitory activity. Finally, we propose that leash-like mimetic peptides may be of value as entry inhibitors for other clinically important viral infections.
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Merimi M, Klener P, Szynal M, Cleuter Y, Bagnis C, Kerkhofs P, Burny A, Martiat P, Van den Broeke A. Complete suppression of viral gene expression is associated with the onset and progression of lymphoid malignancy: observations in Bovine Leukemia Virus-infected sheep. Retrovirology 2007; 4:51. [PMID: 17645797 PMCID: PMC1948017 DOI: 10.1186/1742-4690-4-51] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 07/23/2007] [Indexed: 11/30/2022] Open
Abstract
Background During malignant progression, tumor cells need to acquire novel characteristics that lead to uncontrolled growth and reduced immunogenicity. In the Bovine Leukemia Virus-induced ovine leukemia model, silencing of viral gene expression has been proposed as a mechanism leading to immune evasion. However, whether proviral expression in tumors is completely suppressed in vivo was not conclusively demonstrated. Therefore, we studied viral expression in two selected experimentally-infected sheep, the virus or the disease of which had features that made it possible to distinguish tumor cells from their nontransformed counterparts. Results In the first animal, we observed the emergence of a genetically modified provirus simultaneously with leukemia onset. We found a Tax-mutated (TaxK303) replication-deficient provirus in the malignant B-cell clone while functional provirus (TaxE303) had been consistently monitored over the 17-month aleukemic period. In the second case, both non-transformed and transformed BLV-infected cells were present at the same time, but at distinct sites. While there was potentially-active provirus in the non-leukemic blood B-cell population, as demonstrated by ex-vivo culture and injection into naïve sheep, virus expression was completely suppressed in the malignant B-cells isolated from the lymphoid tumors despite the absence of genetic alterations in the proviral genome. These observations suggest that silencing of viral genes, including the oncoprotein Tax, is associated with tumor onset. Conclusion Our findings suggest that silencing is critical for tumor progression and identify two distinct mechanisms-genetic and epigenetic-involved in the complete suppression of virus and Tax expression. We demonstrate that, in contrast to systems that require sustained oncogene expression, the major viral transforming protein Tax can be turned-off without reversing the transformed phenotype. We propose that suppression of viral gene expression is a contributory factor in the impairment of immune surveillance and the uncontrolled proliferation of the BLV-infected tumor cell.
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Affiliation(s)
- Makram Merimi
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Pavel Klener
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
- Institute of Pathological Physiology, Charles University, Prague, Czech Republic
| | - Maud Szynal
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Yvette Cleuter
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Claude Bagnis
- Etablissement Français du Sang, 13009 Marseille, France
| | | | - Arsène Burny
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Philippe Martiat
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Anne Van den Broeke
- Laboratory of Experimental Hematology, Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
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Merimi M, Klener P, Szynal M, Cleuter Y, Kerkhofs P, Burny A, Martiat P, Van den Broeke A. Suppression of viral gene expression in bovine leukemia virus-associated B-cell malignancy: interplay of epigenetic modifications leading to chromatin with a repressive histone code. J Virol 2007; 81:5929-39. [PMID: 17392371 PMCID: PMC1900279 DOI: 10.1128/jvi.02606-06] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ovine leukemia/lymphoma resulting from bovine leukemia virus infection of sheep offers a large animal model for studying mechanisms underlying leukemogenesis. Silencing of viral information including Tax, the major contributor to the oncogenic potential of the virus, is critical if not mandatory for tumor progression. In this study, we have identified epigenetic mechanisms that govern the complete suppression of viral expression, using a lymphoma-derived B-cell clone carrying a silent provirus. Silencing was not relieved by injection of the malignant B cells into sheep. However, exogenous expression of Tax or treatment with either the DNA methyltransferase inhibitor 5'azacytidine or the histone deacetylase (HDAC) inhibitor trichostatin A rescued viral expression, as demonstrated by in vivo infectivity trials. Comparing silent and reactivated provirus, we found mechanistic connections between chromatin conformation and tumor-associated transcriptional repression. Silencing is associated with DNA methylation and decreased accessibility of promoter sequences. HDAC1 and the transcriptional corepressor mSin3A are associated with the inactive but not the reactivated promoter. Silencing correlates with a repressed chromatin structure marked by histone H3 and H4 hypoacetylation, a loss of methylation at H3 lysine 4, and an increase of H3 lysine 9 methylation. These observations point to the critical role of epigenetic mechanisms in tumor-specific virus/oncogene silencing, a potential strategy to evade immune response and favor the propagation of the transformed cell.
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Affiliation(s)
- Makram Merimi
- Laboratory of Experimental Hematology, Bordet Institute, ULB, 121, Blvd. de Waterloo, 1000 Brussels, Belgium
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24
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Sun J, Barbeau B, Tremblay MJ. HIV-1-mediated syncytium formation promotes cell-to-cell transfer of Tax protein and HTLV-I gene expression. Virus Res 2006; 118:120-9. [PMID: 16413627 DOI: 10.1016/j.virusres.2005.10.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 10/26/2005] [Accepted: 10/30/2005] [Indexed: 10/25/2022]
Abstract
An important increase in luciferase activity was detected following co-culture of Jurkat T cells transiently transfected with an HTLV-I-LTR-driven reporter construct with HIV-1- and HTLV-I-infected cells. Production of infectious HTLV-I and expression of the HTLV-I envelope were not required for this HIV-1-dependent induction while it was severely hampered by anti-gp120 and anti-CD4 antibodies. The HTLV-I Tax protein and the TRE1 repeats were found to be necessary for the HIV-1-mediated enhancement of HTLV-I LTR activity in the co-culture assay. As these results suggested triple fusion events involving all three cell types and the intracellular transfer of Tax, we labelled each cell line with a distinct fluorescent probe. Through confocal microscopy, a number of resulting syncytia and cell clusters were indeed observed to be positive for all three probes. We are proposing a model in which HIV-1-mediated syncytium formation between HIV-1- and HTLV-I-infected cells and uninfected T cells forms a "bridge" or "tunnel" through which Tax from the HTLV-I-infected cells can diffuse and activate HTLV-I-LTR transcription.
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Affiliation(s)
- Jiangfeng Sun
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario and Faculty of Medicine, Laval University, Que., Canada
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25
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Achachi A, Florins A, Gillet N, Debacq C, Urbain P, Foutsop GM, Vandermeers F, Jasik A, Reichert M, Kerkhofs P, Lagneaux L, Burny A, Kettmann R, Willems L. Valproate activates bovine leukemia virus gene expression, triggers apoptosis, and induces leukemia/lymphoma regression in vivo. Proc Natl Acad Sci U S A 2005; 102:10309-14. [PMID: 16006517 PMCID: PMC1177395 DOI: 10.1073/pnas.0504248102] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Leukemogenic viruses like human T-lymphotropic virus and bovine leukemia virus (BLV) presumably persist in the host partly by latent integration of the provirus in a fraction of infected cells, leading to accumulative increase in the outgrowth of transformed cells. Furthermore, viral infection also correlates with a blockade of the apoptotic mechanisms concomitant with an apparent latency of the host cell. Conceptually, induction of viral or cellular gene expression could thus also be used as a therapeutic strategy against retroviral-associated leukemia. Here, we provide evidence that valproate, an inhibitor of deacetylases, activates BLV gene expression in transient transfection experiments and in short-term cultures of primary B-lymphocytes. In vivo, valproate injection into newly BLV-inoculated sheep did not abrogate primary infection. However, valproate treatment, in the absence of any other cytotoxic drug, was efficient for leukemia/lymphoma therapy in the sheep model leading to decreased lymphocyte numbers (respectively from 25.6, 35.7, and 46.5 x 10(3) cells per mm3 to 1.0, 10.6, and 24.3 x 10(3) cells per mm3 in three leukemic sheep) and tumor regression (from >700 cm3 to undetectable). The concept of a therapy that targets the expression of viral and cellular genes might be a promising treatment of adult T cell leukemia or tropical spastic paraparesis/human T-lymphotropic virus-associated myelopathy, diseases for which no satisfactory treatment exists so far.
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Affiliation(s)
- Amine Achachi
- Molecular and Cellular Biology, Gembloux University Faculty of Agronomic Sciences, 5030 Gembloux, Belgium
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26
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Davis DM, Igakura T, McCann FE, Carlin LM, Andersson K, Vanherberghen B, Sjöström A, Bangham CRM, Höglund P. The protean immune cell synapse: a supramolecular structure with many functions. Semin Immunol 2003; 15:317-24. [PMID: 15001170 DOI: 10.1016/j.smim.2003.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Heterogeneity in the supramolecular organization of immunological synapses arises from the involvement of different cells, distinct environmental stimuli, and varying levels of protein expression. There may also be heterogeneity in the types and amounts of cell surface proteins and lipids that transfer between lymphocytes during immune surveillance. In addition, immune cells can be involved in the assembly of a 'viral synapse', such that micrometer-scale organization of proteins at intercellular contacts occurs during transmission of a virus between T cells. Thus, while there may be unity in molecular mechanisms underlying the organization of cell surface receptors at immune cell synapses, there is diversity in their function.
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Affiliation(s)
- Daniel M Davis
- Department of Biological Sciences, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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27
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Franchini G, Fukumoto R, Fullen JR. T-Cell Control by Human T-Cell Leukemia/Lymphoma Virus Type 1. Int J Hematol 2003; 78:280-96. [PMID: 14686485 DOI: 10.1007/bf02983552] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Collective evidence from in vitro studies indicates that several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function, such as antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation may therefore be of importance, as also suggested by epidemiological data. Thus genetic and environmental factors together with the virus contribute to disease development. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells. The relevance of these laboratory findings is related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.
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Affiliation(s)
- Genoveffa Franchini
- Basic Research Laboratory, National Cancer Institute, Bethesda, Maryland 20892-5055, USA.
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28
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Piñón JD, Kelly SM, Price NC, Flanagan JU, Brighty DW. An antiviral peptide targets a coiled-coil domain of the human T-cell leukemia virus envelope glycoprotein. J Virol 2003; 77:3281-90. [PMID: 12584351 PMCID: PMC149751 DOI: 10.1128/jvi.77.5.3281-3290.2003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Retrovirus entry into cells is mediated by the viral envelope glycoproteins which, through a cascade of conformational changes, orchestrate fusion of the viral and cellular membranes. In the absence of membrane fusion, viral entry into the host cell cannot occur. For human T-cell leukemia virus type 1 (HTLV-1), synthetic peptides that mimic a carboxy-terminal region of the transmembrane glycoprotein (TM) ectodomain are potent inhibitors of membrane fusion and virus entry. Here, we demonstrate that this class of inhibitor targets a fusion-active structure of HTLV-1 envelope. In particular, the peptides bind specifically to a core coiled-coil domain of envelope, and peptide variants that fail to bind the coiled-coil lack inhibitory activity. Our data indicate that the inhibitory peptides likely function by disrupting the formation of a trimer-of-hairpins structure that is required for membrane fusion. Importantly, we also show that peptides exhibiting dramatically increased potency can be readily obtained. We suggest that peptides or peptide mimetics targeting the fusion-active structures of envelope may be of therapeutic value in the treatment of HTLV-1 infections.
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Affiliation(s)
- Josefina D Piñón
- The Biomedical Research Centre, Ninewells Hospital and Medical School, The University, Dundee DD1 9SY, United Kingdom
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29
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Franchini G, Nicot C, Johnson JM. Seizing of T Cells by Human T-Cell Leukemia⧸Lymphoma Virus Type 1. Adv Cancer Res 2003; 89:69-132. [PMID: 14587871 DOI: 10.1016/s0065-230x(03)01003-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function. Viral proteins modulate the downstream effects of antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation are therefore important, as also suggested by epidemiological data. The ability of a given individual to respond to specific antigens is determined genetically. Thus, genetic and environmental factors, together with the virus, contribute to disease development. As in the case of other virus-associated cancers, HTLV-1-induced leukemia/lymphoma can be prevented by avoiding viral infection or by intervention during the asymptomatic phase with approaches able to interrupt the vicious cycle of virus-induced proliferation of a subset of T-cells. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells in vitro. The relevance of these laboratory findings will be related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.
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Affiliation(s)
- Genoveffa Franchini
- National Cancer Institute, Basic Research Laboratory, Bethesda, Maryland 20892, USA
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30
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Haller K, Wu Y, Derow E, Schmitt I, Jeang KT, Grassmann R. Physical interaction of human T-cell leukemia virus type 1 Tax with cyclin-dependent kinase 4 stimulates the phosphorylation of retinoblastoma protein. Mol Cell Biol 2002; 22:3327-38. [PMID: 11971966 PMCID: PMC133776 DOI: 10.1128/mcb.22.10.3327-3338.2002] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Tax oncoprotein of human T-cell leukemia virus type 1 (HTLV-1) induces leukemia in transgenic mice and permanent T-cell growth in vitro. In transformed lymphocytes, it acts as an essential growth factor. Tax stimulates the cell cycle in the G(1) phase by activating the cyclin-dependent kinase (CDK) CDK4 and CDK6 holoenzyme complexes. Here we show that Tax directly interacts with CDK4. This binding to CDK4 was specific, since Tax did not bind to either CDK2 or CDK1. The interaction with CDK4/cyclin D complexes was observed in vitro, in transfected fibroblasts, in HTLV-1-infected T cells, and in adult T-cell leukemia-derived cultures. Binding studies with several point and deletion mutants indicated that the N terminus of Tax mediates the interaction with CDK4. The Tax/CDK complex represented an active holoenzyme which capably phosphorylates the Rb protein in vitro and is resistant to repression by the inhibitor p21(CIP). Binding-deficient Tax mutants failed to activate CDK4, indicating that direct association with Tax is required for enhanced kinase activity. Tax also increased the association of CDK4 with its positive cyclin regulatory subunit. Thus, protein-protein contact between Tax and the components of the cyclin D/CDK complexes provides a further mechanistic explanation for the mitogenic and immortalizing effects of this HTLV-1 oncoprotein.
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Affiliation(s)
- Kerstin Haller
- Institut für Klinische und Molekulare Virologie, D-91054 Erlangen, Germany
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31
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Grant C, Barmak K, Alefantis T, Yao J, Jacobson S, Wigdahl B. Human T cell leukemia virus type I and neurologic disease: events in bone marrow, peripheral blood, and central nervous system during normal immune surveillance and neuroinflammation. J Cell Physiol 2002; 190:133-59. [PMID: 11807819 DOI: 10.1002/jcp.10053] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Human T cell lymphotropic/leukemia virus type I (HTLV-I) has been identified as the causative agent of both adult T cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the exact sequence of events that occur during the early stages of infection are not known in detail, the initial route of infection may predetermine, along with host, environmental, and viral factors, the subset of target cells and/or the primary immune response encountered by HTLV-I, and whether an HTLV-I-infected individual will remain asymptomatic, develop ATL, or progress to the neuroinflammatory disease, HAM/TSP. Although a large number of studies have indicated that CD4(+) T cells represent an important target for HTLV-I infection in the peripheral blood (PB), additional evidence has accumulated over the past several years demonstrating that HTLV-I can infect several additional cellular compartments in vivo, including CD8(+) T lymphocytes, PB monocytes, dendritic cells, B lymphocytes, and resident central nervous system (CNS) astrocytes. More importantly, extensive latent viral infection of the bone marrow, including cells likely to be hematopoietic progenitor cells, has been observed in individuals with HAM/TSP as well as some asymptomatic carriers, but to a much lesser extent in individuals with ATL. Furthermore, HTLV-I(+) CD34(+) hematopoietic progenitor cells can maintain the intact proviral genome and initiate viral gene expression during the differentiation process. Introduction of HTLV-I-infected bone marrow progenitor cells into the PB, followed by genomic activation and low level viral gene expression may lead to an increase in proviral DNA load in the PB, resulting in a progressive state of immune dysregulation including the generation of a detrimental cytotoxic Tax-specific CD8(+) T cell population, anti-HTLV-I antibodies, and neurotoxic cytokines involved in disruption of myelin-producing cells and neuronal degradation characteristic of HAM/TSP.
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Affiliation(s)
- Christian Grant
- Laboratory for Molecular Retrovirology and Viral Neuropathogenesis, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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