1
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Modulation of mitochondria by viral proteins. Life Sci 2023; 313:121271. [PMID: 36526048 DOI: 10.1016/j.lfs.2022.121271] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/24/2022] [Accepted: 12/03/2022] [Indexed: 12/15/2022]
Abstract
Mitochondria are dynamic cellular organelles with diverse functions including energy production, calcium homeostasis, apoptosis, host innate immune signaling, and disease progression. Several viral proteins specifically target mitochondria to subvert host defense as mitochondria stand out as the most suitable target for the invading viruses. They have acquired the capability to control apoptosis, metabolic state, and evade immune responses in host cells, by targeting mitochondria. In this way, the viruses successfully allow the spread of viral progeny and thus the infection. Viruses employ their proteins to alter mitochondrial dynamics and their specific functions by a modulation of membrane potential, reactive oxygen species, calcium homeostasis, and mitochondrial bioenergetics to help them achieve a state of persistent infection. A better understanding of such viral proteins and their impact on mitochondrial forms and functions is the main focus of this review. We also attempt to emphasize the importance of exploring the role of mitochondria in the context of SARS-CoV2 pathogenesis and identify host-virus protein interactions.
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2
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Hijacking Host Immunity by the Human T-Cell Leukemia Virus Type-1: Implications for Therapeutic and Preventive Vaccines. Viruses 2022; 14:v14102084. [DOI: 10.3390/v14102084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Human T-cell Leukemia virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other inflammatory diseases. High viral DNA burden (VL) in peripheral blood mononuclear cells is a documented risk factor for ATLL and HAM/TSP, and patients with HAM/TSP have a higher VL in cerebrospinal fluid than in peripheral blood. VL alone is not sufficient to differentiate symptomatic patients from healthy carriers, suggesting the importance of other factors, including host immune response. HTLV-1 infection is life-long; CD4+-infected cells are not eradicated by the immune response because HTLV-1 inhibits the function of dendritic cells, monocytes, Natural Killer cells, and adaptive cytotoxic CD8+ responses. Although the majority of infected CD4+ T-cells adopt a resting phenotype, antigen stimulation may result in bursts of viral expression. The antigen-dependent “on-off” viral expression creates “conditional latency” that when combined with ineffective host responses precludes virus eradication. Epidemiological and clinical data suggest that the continuous attempt of the host immunity to eliminate infected cells results in chronic immune activation that can be further exacerbated by co-morbidities, resulting in the development of severe disease. We review cell and animal model studies that uncovered mechanisms used by HTLV-1 to usurp and/or counteract host immunity.
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3
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Mitochondrial calcium signaling in the brain and its modulation by neurotropic viruses. Mitochondrion 2021; 59:8-16. [PMID: 33838333 DOI: 10.1016/j.mito.2021.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/15/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+) plays fundamental and diverse roles in brain cells as a second messenger of many signaling pathways. Given the high energy demand in the brain and the generally non-regenerative state of neurons, the role of brain mitochondrial calcium [Ca2+]m in particular, in regulating ATP generation and determination of cell fate by initiation or inhibition of programmed cell death (PCD) becomes critical. Since [Ca2+]m signaling has a central role in brain physiology, it represents an ideal target for viruses to hijack the Ca2+ machinery to favor their own persistence, replication and/or dissemination by modulating cell death. This review discusses the ways by which neurotropic viruses are known to exploit the [Ca2+]m signaling of their host cells to regulate cell death in the brain, particularly in neurons. We hope our review will highlight the importance of [Ca2+]m handling in the virus-infected brain and stimulate further studies towards exploring novel [Ca2+]m related therapeutic strategies for viral effects on the brain.
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4
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Panda S, Behera S, Alam MF, Syed GH. Endoplasmic reticulum & mitochondrial calcium homeostasis: The interplay with viruses. Mitochondrion 2021; 58:227-242. [PMID: 33775873 DOI: 10.1016/j.mito.2021.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 03/08/2021] [Accepted: 03/22/2021] [Indexed: 02/08/2023]
Abstract
Calcium ions (Ca2+) act as secondary messengers in a plethora of cellular processes and play crucial role in cellular organelle function and homeostasis. The average resting concentration of Ca2+ is nearly 100 nM and in certain cells it can reach up to 1 µM. The high range of Ca2+ concentration across the plasma membrane and intracellular Ca2+ stores demands a well-coordinated maintenance of free Ca2+ via influx, efflux, buffering and storage. Endoplasmic Reticulum (ER) and Mitochondria depend on Ca2+ for their function and also serve as major players in intracellular Ca2+ homeostasis. The ER-mitochondria interplay helps in orchestrating cellular calcium homeostasis to avoid any detrimental effect resulting from Ca2+ overload or depletion. Since Ca2+ plays a central role in many biological processes it is an essential component of the virus-host interactions. The large gradient across membranes enable the viruses to easily modulate this buffered environment to meet their needs. Viruses exploit Ca2+ signaling to establish productive infection and evade the host immune defense. In this review we will detail the interplay between the viruses and cellular & ER-mitochondrial calcium signaling and the significance of these events on viral life cycle and disease pathogenesis.
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Affiliation(s)
- Swagatika Panda
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India
| | - Suchismita Behera
- Institute of Life Sciences, Bhubaneswar, Clinical Proteomics Laboratory, Institute of Life Sciences, Bhubaneswar, India
| | - Mohd Faraz Alam
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India
| | - Gulam Hussain Syed
- Institute of Life Sciences, Bhubaneswar, Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneswar, India.
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5
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Omsland M, Silic-Benussi M, Moles R, Sarkis S, Purcell DFJ, Yurick D, Khoury G, D'Agostino DM, Ciminale V, Franchini G. Functional properties and sequence variation of HTLV-1 p13. Retrovirology 2020; 17:11. [PMID: 32398094 PMCID: PMC7218495 DOI: 10.1186/s12977-020-00517-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/10/2020] [Indexed: 01/06/2023] Open
Abstract
Human T cell leukemia virus type-1 (HTLV-1) was the first retrovirus found to cause cancer in humans, but the mechanisms that drive the development of leukemia and other diseases associated with HTLV-1 infection remain to be fully understood. This review describes the functional properties of p13, an 87-amino acid protein coded by HTLV-1 open reading frame II (orf-II). p13 is mainly localized in the inner membrane of the mitochondria, where it induces potassium (K+) influx and reactive oxygen species (ROS) production, which can trigger either proliferation or apoptosis, depending on the ROS setpoint of the cell. Recent evidence indicates that p13 may influence the cell’s innate immune response to viral infection and the infected cell phenotype. Association of the HTLV-1 transcriptional activator, Tax, with p13 increases p13’s stability, leads to its partial co-localization with Tax in nuclear speckles, and reduces the ability of Tax to interact with the transcription cofactor CBP/p300. Comparison of p13 sequences isolated from HTLV-1-infected individuals revealed a small number of amino acid variations in the domains controlling the subcellular localization of the protein. Disruptive mutations of p13 were found in samples obtained from asymptomatic patients with low proviral load. p13 sequences of HTLV-1 subtype C isolates from indigenous Australian patients showed a high degree of identity among each other, with all samples containing a pattern of 5 amino acids that distinguished them from other subtypes. Further characterization of p13’s functional properties and sequence variants may lead to a deeper understanding of the impact of p13 as a contributor to the clinical manifestations of HTLV-1 infection.
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Affiliation(s)
- Maria Omsland
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Ramona Moles
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Damian F J Purcell
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia
| | - David Yurick
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia
| | - Georges Khoury
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia.,Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | | | - Vincenzo Ciminale
- Veneto Institute of Oncology IOV-IRCCS, Padua, Italy.,Department of Surgery, Oncology, and Gastroenterology, University of Padua, Padua, Italy
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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6
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Georgieva ER, Borbat PP, Fanouraki C, Freed JH. High-yield production in E. coli and characterization of full-length functional p13 II protein from human T-cell leukemia virus type 1. Protein Expr Purif 2020; 173:105659. [PMID: 32360379 DOI: 10.1016/j.pep.2020.105659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 04/20/2020] [Accepted: 04/26/2020] [Indexed: 10/24/2022]
Abstract
Human T-cell leukemia virus type 1 is an oncovirus that causes aggressive adult T-cell leukemia but is also responsible for severe neurodegenerative and endocrine disorders. Combatting HTLV-1 infections requires a detailed understanding of the viral mechanisms in the host. Therefore, in vitro studies of important virus-encoded proteins would be critical. Our focus herein is on the HTLV-1-encoded regulatory protein p13II, which interacts with the inner mitochondrial membrane, increasing its permeability to cations (predominantly potassium, K+). Thereby, this protein affects mitochondrial homeostasis. We report on our progress in developing specific protocols for heterologous expression of p13II in E. coli, and methods for its purification and characterization. We succeeded in producing large quantities of highly-pure full-length p13II, deemed to be its fully functional form. Importantly, our particular approach based on the fusion of ubiquitin to the p13II C-terminus was instrumental in increasing the persistently low expression of soluble p13II in its native form. We subsequently developed approaches for protein spin labeling and a conformation study using double electron-electron resonance (DEER) spectroscopy and a fluorescence-based cation uptake assay for p13II in liposomes. Our DEER results point to large protein conformation changes occurring upon transition from the soluble to the membrane-bound state. The functional assay on p13II-assisted transport of thallium (Tl+) through the membrane, wherein Tl+ substituted for K+, suggests transmembrane potential involvement in p13II function. Our study lays the foundation for expansion of in vitro functional and structural investigations on p13II and would aid in the development of structure-based protein inhibitors and markers.
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Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA; ACERT Center for Advanced ESR Technology, Cornell University, Ithaca, NY, 14853, USA
| | - Christina Fanouraki
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA; ACERT Center for Advanced ESR Technology, Cornell University, Ithaca, NY, 14853, USA
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7
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Georgieva ER. Non-Structural Proteins from Human T-cell Leukemia Virus Type 1 in Cellular Membranes-Mechanisms for Viral Survivability and Proliferation. Int J Mol Sci 2018; 19:ijms19113508. [PMID: 30413005 PMCID: PMC6274929 DOI: 10.3390/ijms19113508] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 12/27/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of illnesses, such as adult T-cell leukemia/lymphoma, myelopathy/tropical spastic paraparesis (a neurodegenerative disorder), and other diseases. Therefore, HTLV-1 infection is a serious public health concern. Currently, diseases caused by HTLV-1 cannot be prevented or cured. Hence, there is a pressing need to comprehensively understand the mechanisms of HTLV-1 infection and intervention in host cell physiology. HTLV-1-encoded non-structural proteins that reside and function in the cellular membranes are of particular interest, because they alter cellular components, signaling pathways, and transcriptional mechanisms. Summarized herein is the current knowledge about the functions of the membrane-associated p8I, p12I, and p13II regulatory non-structural proteins. p12I resides in endomembranes and interacts with host proteins on the pathways of signal transduction, thus preventing immune responses to the virus. p8I is a proteolytic product of p12I residing in the plasma membrane, where it contributes to T-cell deactivation and participates in cellular conduits, enhancing virus transmission. p13II associates with the inner mitochondrial membrane, where it is proposed to function as a potassium channel. Potassium influx through p13II in the matrix causes membrane depolarization and triggers processes that lead to either T-cell activation or cell death through apoptosis.
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Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
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8
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Lai JH, Luo SF, Ho LJ. Operation of mitochondrial machinery in viral infection-induced immune responses. Biochem Pharmacol 2018; 156:348-356. [PMID: 30172712 PMCID: PMC7092938 DOI: 10.1016/j.bcp.2018.08.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 08/29/2018] [Indexed: 01/05/2023]
Abstract
Mitochondria have been recognized as ancient bacteria that contain evolutionary endosymbionts. Metabolic pathways and inflammatory signals interact within mitochondria in response to different stresses, such as viral infections. In this commentary, we address several interesting questions, including (1) how do mitochondrial machineries participate in immune responses; (2) how do mitochondria mediate antiviral immunity; (3) what mechanisms involved in mitochondrial machinery, including the downregulation of mitochondrial DNA (mtDNA), disturbances of mitochondrial dynamics, and the induction of mitophagy and regulation of apoptosis, have been adopted by viruses to evade antiviral immunity; (4) what mechanisms involve the regulation of mitochondrial machineries in antiviral therapeutics; and (5) what are the potential challenges and perspectives in developing mitochondria-targeting antiviral treatments? This commentary provides a comprehensive review of the roles and mechanisms of mitochondrial machineries in immunity, viral infections and related antiviral therapeutics.
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Affiliation(s)
- Jenn-Haung Lai
- Division of Allergy, Immunology, and Rheumatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Tao-Yuan, Taiwan, ROC; Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan, ROC.
| | - Shue-Fen Luo
- Division of Allergy, Immunology, and Rheumatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Tao-Yuan, Taiwan, ROC
| | - Ling-Jun Ho
- Institute of Cellular and System Medicine, National Health Research Institute, Zhunan, Taiwan, ROC.
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9
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Cavallari I, Scattolin G, Silic-Benussi M, Raimondi V, D'Agostino DM, Ciminale V. Mitochondrial Proteins Coded by Human Tumor Viruses. Front Microbiol 2018; 9:81. [PMID: 29467726 PMCID: PMC5808139 DOI: 10.3389/fmicb.2018.00081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/12/2018] [Indexed: 12/26/2022] Open
Abstract
Viruses must exploit the cellular biosynthetic machinery and evade cellular defense systems to complete their life cycles. Due to their crucial roles in cellular bioenergetics, apoptosis, innate immunity and redox balance, mitochondria are important functional targets of many viruses, including tumor viruses. The present review describes the interactions between mitochondria and proteins coded by the human tumor viruses human T-cell leukemia virus type 1, Epstein-Barr virus, Kaposi's sarcoma-associated herpesvirus, human hepatitis viruses B and C, and human papillomavirus, and highlights how these interactions contribute to viral replication, persistence and transformation.
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Affiliation(s)
| | - Gloria Scattolin
- Department of Surgery, Oncology, and Gastroenterology, University of Padova, Padova, Italy
| | | | | | | | - Vincenzo Ciminale
- Veneto Institute of Oncology IOV-IRRCS, Padova, Italy.,Department of Surgery, Oncology, and Gastroenterology, University of Padova, Padova, Italy
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10
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Song S, Gong S, Singh P, Lyu J, Bai Y. The interaction between mitochondria and oncoviruses. Biochim Biophys Acta Mol Basis Dis 2018; 1864:481-487. [PMID: 28962899 PMCID: PMC8895674 DOI: 10.1016/j.bbadis.2017.09.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 09/23/2017] [Accepted: 09/25/2017] [Indexed: 12/24/2022]
Abstract
Mitochondria play important roles in multiple aspects of viral tumorigenesis. Mitochondrial genomes contribute to the host's genetic background. After viruses enter the cell, they modulate mitochondrial function and thus alter bioenergetics and retrograde signaling pathways. At the same time, mitochondria also regulate and mediate viral oncogenesis. In this context, oncogenesis by oncoviruses like Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human papilloma virus (HPV), Human Immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) will be discussed.
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Affiliation(s)
- Shujie Song
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shasha Gong
- School of Medicine, Taizhou College, Taizhou, Zhejiang, China
| | - Pragya Singh
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Jianxin Lyu
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China,Corresponding author: Wenzhou Medical University, Chashan, Wenzhou 325035, China. (J. Lyu); (Y. Bai). Fax: 86-577-86689771; Tel: 86-577-86689805
| | - Yidong Bai
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas, USA,Corresponding author: Wenzhou Medical University, Chashan, Wenzhou 325035, China. (J. Lyu); (Y. Bai). Fax: 86-577-86689771; Tel: 86-577-86689805
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11
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Kadio B, Yaya S, Basak A, Djè K, Gomes J, Mesenge C. Calcium role in human carcinogenesis: a comprehensive analysis and critical review of literature. Cancer Metastasis Rev 2017; 35:391-411. [PMID: 27514544 DOI: 10.1007/s10555-016-9634-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The central role played by calcium ion in biological systems has generated an interest for its potential implication in human malignancies. Thus, lines of research, on possible association of calcium metabolism regulation with tumorigenesis, implying disruptions and/or alterations of known molecular pathways, have been extensively researched in the recent decades. This paper is a critical synthesis of these findings, based on a functional approach of the calcium signaling toolkit. It provides strong support that this ubiquitous divalent cation is involved in cancer initiation, promotion, and progression. Different pathways have been outlined, involving equally different molecular and cellular structures. However, if the association between calcium and cancer can be described as constant, it is not always linear. We have identified several influencing factors among which the most relevant are (i) the changes in local or tissular concentrations of free calcium and (ii) the histological and physiological types of tissue involved. Such versatility at the molecular level may probably account for the conflicting findings reported by the epidemiological literature on calcium dietary intake and the risk to develop certain cancers such as the prostatic or mammary neoplasms. However, it also fuels the hypothesis that behind each cancer, a specific calcium pathway can be evidenced. Identifying such molecular interactions is probably a promising approach for further understanding and treatment options for the disease.
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Affiliation(s)
- Bernard Kadio
- Interdisciplinary School of Health Sciences, Faculty of Health Science, University of Ottawa, Ottawa, Canada
| | - Sanni Yaya
- School of International Development and Global Studies, Faculty of Social Sciences, University of Ottawa, Social Science Building, 120 University Private, Ottawa, ON, K1N 6N5, Canada.
| | - Ajoy Basak
- Chronic Disease Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
- Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Koffi Djè
- Faculty of Médecine, Department of Urology, Allasane Ouattara University, Bouaké, Ivory Coast
| | - James Gomes
- Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Canada
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12
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Inefficient viral replication of bovine leukemia virus induced by spontaneous deletion mutation in the G4 gene. J Gen Virol 2016; 97:2753-2762. [DOI: 10.1099/jgv.0.000583] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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13
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Bai XT, Nicot C. Overview on HTLV-1 p12, p8, p30, p13: accomplices in persistent infection and viral pathogenesis. Front Microbiol 2012; 3:400. [PMID: 23248621 PMCID: PMC3518833 DOI: 10.3389/fmicb.2012.00400] [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: 07/20/2012] [Indexed: 12/29/2022] Open
Abstract
The human T-lymphotropic virus type-1 (HTLV-1) is etiologically linked to adult T cell leukemia/lymphoma and tropical spastic paraparesis/HTLV-1-associated myelopathy. While the role of Tax and Rex in viral replication and pathogenesis has been extensively studied, recent evidence suggests that additional viral proteins are essential for the virus life cycle in vivo. In this review, we will summarize possible molecular mechanisms evoked in the literature to explain how p12, p8, p30, and p13 facilitate persistent viral infection of the host. We will explore several stratagems used by HTLV-1 accessory genes to escape immune surveillance, to establish latency, and to deregulate cell cycle and apoptosis to participate in virus-mediated cellular transformation.
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Affiliation(s)
- Xue Tao Bai
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center Kansas City, KS, USA
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14
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Williamson CD, DeBiasi RL, Colberg-Poley AM. Viral product trafficking to mitochondria, mechanisms and roles in pathogenesis. Infect Disord Drug Targets 2012; 12:18-37. [PMID: 22034933 PMCID: PMC4435936 DOI: 10.2174/187152612798994948] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/21/2011] [Accepted: 05/02/2011] [Indexed: 05/31/2023]
Abstract
A wide variety of viruses cause significant morbidity and mortality in humans. However, targeted antiviral therapies have been developed for only a subset of these viruses, with the majority of currently licensed antiviral drugs targeting viral entry, replication or exit steps during the viral life cycle. Due to increasing emergence of antiviral drug resistant viruses, the isolation of multiple viral subtypes, and toxicities of existing therapies, there remains an urgent need for the timely development of novel antiviral agents, including those targeting host factors essential for viral replication. This review summarizes viral products that target mitochondria and their effects on common mitochondria regulated pathways. These viral products and the mitochondrial pathways affected by them provide potential novel targets for the rational design of antiviral drugs. Viral products alter oxidative balance, mitochondrial permeability transition pore, mitochondrial membrane potential, electron transport and energy production. Moreover, viruses may cause the Warburg Effect, in which metabolism is reprogrammed to aerobic glycolysis as the main source of energy. Finally, viral products affect proapoptotic and antiapoptotic signaling, as well as mitochondrial innate immune signaling. Because of their importance for the generation of metabolic intermediates and energy as well as cell survival, mitochondrial pathways are targeted by multiple independent viral products. Structural modifications of existing drugs targeted to mitochondrial pathways may lead to the development of novel antiviral drugs with improved efficacy and reduced toxicity.
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Affiliation(s)
- Chad D. Williamson
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
| | - Roberta L. DeBiasi
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Division of Pediatric Infectious Diseases, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
| | - Anamaris M. Colberg-Poley
- Center for Cancer and Immunology Research, Children’s National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010
- Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
- Department of Biochemistry and Molecular Biology, George Washington University School of Medicine and Health Sciences, Washington DC 20037 Tel. 202-476-3984 FAX 202-476-3929
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15
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Neto WK, Da-Costa AC, de Oliveira ACS, Martinez VP, Nukui Y, Sabino EC, Sanabani SS. Correlation between LTR point mutations and proviral load levels among human T cell lymphotropic virus type 1 (HTLV-1) asymptomatic carriers. Virol J 2011; 8:535. [PMID: 22166003 PMCID: PMC3287369 DOI: 10.1186/1743-422x-8-535] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/13/2011] [Indexed: 02/01/2023] Open
Abstract
Background In vitro studies have demonstrated that deletions and point mutations introduced into each 21 bp imperfect repeat of Tax-responsive element (TRE) of the genuine human T-cell leukemia virus type I (HTLV-1) viral promoter abolishes Tax induction. Given these data, we hypothesized that similar mutations may affect the proliferation of HTLV-1i nfected cells and alter the proviral load (PvL). To test this hypothesis, we conducted a cross-sectional genetic analysis to compare the near-complete LTR nucleotide sequences that cover the TRE1 region in a sample of HTLV-1 asymptomatic carriers with different PvL burden. Methods A total of 94 asymptomatic HTLV-1 carriers with both sequence from the 5' long terminal repeat (LTR) and a PvL for Tax DNA measured using a sensitive SYBR Green real-time PCR were studied. The 94 subjects were divided into three groups based on PvL measurement: 31 low, 29 intermediate, and 34 high. In addition, each group was compared based on sex, age, and viral genotypes. In another analysis, the median PvLs between individuals infected with mutant and wild-type viruses were compared. Results Using a categorical analysis, a G232A substitution, located in domain A of the TRE-1 motif, was detected in 38.7% (12/31), 27.5% (8/29), and 61.8% (21/34) of subjects with low, intermediate, or high PvLs, respectively. A significant difference in the detection of this mutation was found between subjects with a high or low PvL and between those with a high or intermediate PvL (both p < 0.05), but not between subjects with a low or intermediate PvL (p > 0.05). This result was confirmed by a non-parametric analysis that showed strong evidence for higher PvLs among HTLV-1 positive individuals with the G232A mutation than those without this mutation (p < 0.03). No significant difference was found between the groups in relation to age, sex or viral subtypes (p > 0. 05). Conclusions The data described here show that changes in domain A of the HTLV-1 TRE-1 motif resulting in the G232A mutation may increase HTLV-1 replication in a majority of infected subjects.
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Affiliation(s)
- Walter K Neto
- Fundação Pro-Sangue, Blood Center of São Paulo, São Paulo, Brazil
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Cavallari I, Rende F, D'Agostino DM, Ciminale V. Converging strategies in expression of human complex retroviruses. Viruses 2011; 3:1395-414. [PMID: 21994786 PMCID: PMC3185809 DOI: 10.3390/v3081395] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 07/28/2011] [Accepted: 07/28/2011] [Indexed: 12/27/2022] Open
Abstract
The discovery of human retroviruses in the early 1980s revealed the existence of viral-encoded non-structural genes that were not evident in previously described animal retroviruses. Based on the absence or presence of these additional genes retroviruses were classified as ‘simple’ and ‘complex’, respectively. Expression of most of these extra genes is achieved through the generation of alternatively spliced mRNAs. The present review summarizes the genetic organization and expression strategies of human complex retroviruses and highlights the converging mechanisms controlling their life cycles.
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Affiliation(s)
- Ilaria Cavallari
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
| | - Francesca Rende
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
- Istituto Oncologico Veneto-IRCCS, I-35128 Padova, Italy
| | - Donna M. D'Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
| | - Vincenzo Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Via Gattamelata 64, I-35128 Padova, Italy; E-Mails: (I.C.); (F.R.); (D.M.D.)
- Istituto Oncologico Veneto-IRCCS, I-35128 Padova, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.:+39-049-821-5885; Fax: +39-049-807-2854
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Suppression of HTLV-1 replication by Tax-mediated rerouting of the p13 viral protein to nuclear speckles. Blood 2011; 118:1549-59. [PMID: 21677314 DOI: 10.1182/blood-2010-06-293340] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Disease development in human T-cell leukemia virus type 1 (HTLV-1)-infected individuals is positively correlated with the level of integrated viral DNA in T cells. HTLV-1 replication is positively regulated by Tax and Rex and negatively regulated by the p30 and HBZ proteins. In the present study, we demonstrate that HTLV-1 encodes another negative regulator of virus expression, the p13 protein. Expressed separately, p13 localizes to the mitochondria, whereas in the presence of Tax, part of it is ubiquitinated, stabilized, and rerouted to the nuclear speckles. The p13 protein directly binds Tax, decreases Tax binding to the CBP/p300 transcriptional coactivator, and, by reducing Tax transcriptional activity, suppresses viral expression. Because Tax stabilizes its own repressor, these findings suggest that HTLV-1 has evolved a complex mechanism to control its own replication. Further, these results highlight the importance of studying the function of the HTLV-1 viral proteins, not only in isolation, but also in the context of full viral replication.
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18
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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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19
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Abstract
Mitochondria are involved in a variety of cellular metabolic processes, and their functions are regulated by extrinsic and intrinsic stimuli including viruses. Recent studies have shown that mitochondria play a central role in the primary host defense mechanisms against viral infections, and a number of novel viral and mitochondrial proteins are involved in these processes. Some viral proteins localize in mitochondria and interact with mitochondrial proteins to regulate cellular responses. This review summarizes recent findings on the functions and roles of these molecules as well as mitochondrial responses to viral infections.
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20
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Redox regulation of T-cell turnover by the p13 protein of human T-cell leukemia virus type 1: distinct effects in primary versus transformed cells. Blood 2010; 116:54-62. [DOI: 10.1182/blood-2009-07-235861] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AbstractThe present study investigated the function of p13, a mitochondrial protein of human T-cell leukemia virus type 1 (HTLV-1). Although necessary for viral propagation in vivo, the mechanism of function of p13 is incompletely understood. Drawing from studies in isolated mitochondria, we analyzed the effects of p13 on mitochondrial reactive oxygen species (ROS) in transformed and primary T cells. In transformed cells (Jurkat, HeLa), p13 did not affect ROS unless the cells were subjected to glucose deprivation, which led to a p13-dependent increase in ROS and cell death. Using RNA interference we confirmed that expression of p13 also influences glucose starvation-induced cell death in the context of HTLV-1–infected cells. ROS measurements showed an increasing gradient from resting to mitogen-activated primary T cells to transformed T cells (Jurkat). Expression of p13 in primary T cells resulted in their activation, an effect that was abrogated by ROS scavengers. These findings suggest that p13 may have a distinct impact on cell turnover depending on the inherent ROS levels; in the context of the HTLV-1 propagation strategy, p13 could increase the pool of “normal” infected cells while culling cells acquiring a transformed phenotype, thus favoring lifelong persistence of the virus in the host.
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21
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Bai XT, Baydoun HH, Nicot C. HTLV-I p30: a versatile protein modulating virus replication and pathogenesis. Mol Aspects Med 2010; 31:344-9. [PMID: 20595036 DOI: 10.1016/j.mam.2010.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 02/15/2010] [Accepted: 05/28/2010] [Indexed: 12/01/2022]
Affiliation(s)
- Xue Tao Bai
- University of Kansas Medical Center, Department of Pathology and Laboratory Medicine, Kansas City, KS 66160, USA
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22
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Biasiotto R, Aguiari P, Rizzuto R, Pinton P, D'Agostino DM, Ciminale V. The p13 protein of human T cell leukemia virus type 1 (HTLV-1) modulates mitochondrial membrane potential and calcium uptake. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:945-51. [DOI: 10.1016/j.bbabio.2010.02.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 11/24/2022]
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23
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Bergonzini V, Salata C, Calistri A, Parolin C, Palù G. View and review on viral oncology research. Infect Agent Cancer 2010; 5:11. [PMID: 20497566 PMCID: PMC2881002 DOI: 10.1186/1750-9378-5-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 05/24/2010] [Indexed: 01/05/2023] Open
Abstract
To date, almost one and a half million cases of cancer are diagnosed every year in the US and nearly 560,000 Americans are expected to die of cancer in the current year, more than 1,500 people a day (data from the American Cancer Society at http://www.cancer.org/). According to the World Health Organization (WHO), roughly 20% of all cancers worldwide results from chronic infections; in particular, up to 15% of human cancers is characterized by a viral aetiology with higher incidence in Developing Countries. The link between viruses and cancer was one of the pivotal discoveries in cancer research during the past Century. Indeed, the infectious nature of specific tumors has important implications in terms of their prevention, diagnosis, and therapy. In the 21st Century, the research on viral oncology field continues to be vigorous, with new significant and original studies on viral oncogenesis and translational research from basic virology to treatment of cancer. This review will cover different viral oncology aspects, starting from the history of viral oncology and moving to the peculiar features of oncogenic RNA and DNA viruses, with a special focus on human pathogens.
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Affiliation(s)
- Valeria Bergonzini
- Department of Histology, Microbiology and Medical Biotechnologies, Division of Microbiology and Virology, University of Padova, Via A Gabelli 63, Padova 35121, Italy
| | - Cristiano Salata
- Department of Histology, Microbiology and Medical Biotechnologies, Division of Microbiology and Virology, University of Padova, Via A Gabelli 63, Padova 35121, Italy
| | - Arianna Calistri
- Department of Histology, Microbiology and Medical Biotechnologies, Division of Microbiology and Virology, University of Padova, Via A Gabelli 63, Padova 35121, Italy
| | - Cristina Parolin
- Department of Biology, University of Padova, Via Ugo Bassi 58B, Padova 35123, Italy
| | - Giorgio Palù
- Department of Histology, Microbiology and Medical Biotechnologies, Division of Microbiology and Virology, University of Padova, Via A Gabelli 63, Padova 35121, Italy
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24
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Zhou Y, Frey TK, Yang JJ. Viral calciomics: interplays between Ca2+ and virus. Cell Calcium 2009; 46:1-17. [PMID: 19535138 PMCID: PMC3449087 DOI: 10.1016/j.ceca.2009.05.005] [Citation(s) in RCA: 206] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 12/23/2022]
Abstract
Ca2+ is one of the most universal and versatile signaling molecules and is involved in almost every aspect of cellular processes. Viruses are adept at utilizing the universal Ca2+ signal to create a tailored cellular environment that meets their own demands. This review summarizes most of the known mechanisms by which viruses perturb Ca2+ homeostasis and utilize Ca2+ and cellular Ca2+-binding proteins to their benefit in their replication cycles. Ca2+ plays important roles in virion structure formation, virus entry, viral gene expression, posttranslational processing of viral proteins and virion maturation and release. As part of the review, we introduce an algorithm to identify linear “EF-hand” Ca2+-binding motifs which resulted in the prediction of a total of 93 previously unrecognized Ca2+-binding motifs in virus proteins. Many of these proteins are nonstructural proteins, a class of proteins among which Ca2+ interactions had not been formerly appreciated. The presence of linear Ca2+-binding motifs in viral proteins enlarges the spectrum of Ca2+–virus interplay and expands the total scenario of viral calciomics.
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Affiliation(s)
- Yubin Zhou
- Department of Chemistry, Georgia State University, 50 Decatur St., Atlanta, GA 30303 USA
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25
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Journo C, Douceron E, Mahieux R. HTLV gene regulation: because size matters, transcription is not enough. Future Microbiol 2009; 4:425-40. [PMID: 19416012 DOI: 10.2217/fmb.09.13] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Despite being discovered in animals in the early 20th century, the scientific interest in retroviruses was boosted with the discovery of human retroviruses (human T-leukemia/lymphoma virus [HTLV] and HIV), which are responsible for significant morbidity and mortality. HTLV was identified more than 25 years ago as the etiological agent of adult T-cell leukemia/lymphoma. It was then shown to be a complex retrovirus, given that it not only encodes the characteristic retroviral Gag, Pol and Env proteins, but also regulatory and accessory proteins. Since the first studies documenting the role of these proteins in viral expression, the picture has become increasingly more complex. Indeed, owing to the limited size of its genome that contains overlapping open-reading frames, HTLV has evolved unique ways to regulate its expression. Retroviral expression was originally thought to be mainly controlled through the regulation of transcription from the 5 long-terminal repeats, but we now know that the 3 long-terminal repeats also serve as promoters. Regulation of splicing and mRNA export, and post-translational modifications of viral protein also play a major role. This review discusses the latest insights gained into the field of HTLV gene expression.
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Affiliation(s)
- Chloé Journo
- Equipe Oncogenèse Rétrovirale, INSERM-U758 Virologie Humaine, 69364 Lyon Cedex 07, France
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26
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Silic-Benussi M, Cannizzaro E, Venerando A, Cavallari I, Petronilli V, La Rocca N, Marin O, Chieco-Bianchi L, Di Lisa F, D'Agostino DM, Bernardi P, Ciminale V. Modulation of mitochondrial K(+) permeability and reactive oxygen species production by the p13 protein of human T-cell leukemia virus type 1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:947-54. [PMID: 19366603 DOI: 10.1016/j.bbabio.2009.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 01/31/2009] [Accepted: 02/05/2009] [Indexed: 01/28/2023]
Abstract
Human T-cell leukemia virus type-1 (HTLV-1) expresses an 87-amino acid protein named p13 that is targeted to the inner mitochondrial membrane. Previous studies showed that a synthetic peptide spanning an alpha helical domain of p13 alters mitochondrial membrane permeability to cations, resulting in swelling. The present study examined the effects of full-length p13 on isolated, energized mitochondria. Results demonstrated that p13 triggers an inward K(+) current that leads to mitochondrial swelling and confers a crescent-like morphology distinct from that caused by opening of the permeability transition pore. p13 also induces depolarization, with a matching increase in respiratory chain activity, and augments production of reactive oxygen species (ROS). These effects require an intact alpha helical domain and strictly depend on the presence of K(+) in the assay medium. The effects of p13 on ROS are mimicked by the K(+) ionophore valinomycin, while the protonophore FCCP decreases ROS, indicating that depolarization induced by K(+) vs. H(+) currents has different effects on mitochondrial ROS production, possibly because of their opposite effects on matrix pH (alkalinization and acidification, respectively). The downstream consequences of p13-induced mitochondrial K(+) permeability are likely to have an important influence on the redox state and turnover of HTLV-1-infected cells.
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Affiliation(s)
- Micol Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padova, I-35128 Padova, Italy
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27
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Baydoun HH, Bellon M, Nicot C. HTLV-1 Yin and Yang: Rex and p30 master regulators of viral mRNA trafficking. AIDS Rev 2008; 10:195-204. [PMID: 19092975 PMCID: PMC2666328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Human retroviruses are associated with a variety of malignancies including Kaposi's sarcoma and Epstein-Barr virus-associated lymphoma in HIV infection, T-cell leukemia/lymphoma and a neurologic disorder in human T-cell lymphotropic virus type 1 (HTLV-1) infection. Both HIV and human T-cell lymphotropic virus type 1 have evolved a complex genetic organization for optimal use of their limited genome and production of all necessary structural and regulatory proteins. Use of alternative splicing is essential for balanced expression of multiple viral regulators from one genomic polycistronic RNA. In addition, nuclear export of incompletely spliced RNA is required for production of structural and enzymatic proteins and virus particles. Decisions controlling these events are largely guarded by viral proteins. In human T-cell lymphotropic virus type 1, Rex and p30 are both nuclear/nucleolar RNA binding regulatory proteins. Rex interacts with a Rex-responsive element to stimulate nuclear export of incompletely spliced RNA and increase production of virus particles. In contrast, human T-cell lymphotropic virus type 1 p30 is involved in the nuclear retention of the tax/rex mRNA leading to inhibition of virus expression and establishment of viral latency. How these two proteins, with apparently opposite functions, orchestrate virus replication and ensure vigilant control of viral gene expression is discussed.
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Affiliation(s)
- Hicham H Baydoun
- University of Kansas Medical Center, Department of Pathology and Laboratory Medicine, Center for Viral Oncology, KU Cancer Center, Kansas City, KS 66160, USA
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28
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Taylor JM, Nicot C. HTLV-1 and apoptosis: role in cellular transformation and recent advances in therapeutic approaches. Apoptosis 2008; 13:733-47. [PMID: 18421579 DOI: 10.1007/s10495-008-0208-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A universal cellular defense mechanism against viral invasion is the elimination of infected cells through apoptotic cell death. To counteract host defenses many viruses have evolved complex apoptosis evasion strategies. The oncogenic human retrovirus HTLV-1 is the etiological agent of adult-T-cell leukemia/lymphoma (ATLL) and the neurodegenerative disease known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The poor prognosis in HTLV-1-induced ATLL is linked to the resistance of neoplastic T cells against conventional therapies and the immuno-compromised state of patients. Nevertheless, several studies have shown that the apoptotic pathway is largely intact and can be reactivated in ATLL tumor cells to induce specific killing. A better understanding of the molecular mechanisms employed by HTLV-1 to counteract cellular death pathways remains an important challenge for future therapies and the treatment of HTLV-1-associated diseases.
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Affiliation(s)
- John M Taylor
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kansas Medical Center, 3025 Wahl Hall West, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
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29
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Abstract
Throughout the process of pathogen–host co-evolution, viruses have developed a battery of distinct strategies to overcome biochemical and immunological defenses of the host. Thus, viruses have acquired the capacity to subvert host cell apoptosis, control inflammatory responses, and evade immune reactions. Since the elimination of infected cells via programmed cell death is one of the most ancestral defense mechanisms against infection, disabling host cell apoptosis might represent an almost obligate step in the viral life cycle. Conversely, viruses may take advantage of stimulating apoptosis, either to kill uninfected cells from the immune system, or to induce the breakdown of infected cells, thereby favoring viral dissemination. Several viral polypeptides are homologs of host-derived apoptosis-regulatory proteins, such as members of the Bcl-2 family. Moreover, viral factors with no homology to host proteins specifically target key components of the apoptotic machinery. Here, we summarize the current knowledge on the viral modulation of mitochondrial apoptosis, by focusing in particular on the mechanisms by which viral proteins control the host cell death apparatus.
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Affiliation(s)
- Lorenzo Galluzzi
- INSERM, U848, Villejuif, France
- Institut Gustave Roussy, Villejuif, France
- Faculté de Médecine, Université Paris-Sud 11, Villejuif, France
| | - Catherine Brenner
- University of Versailles/St Quentin, PRES UniverSud Paris, CNRS UMR8159, Versailles, France
- * E-mail: (CB); (GK)
| | - Eugenia Morselli
- INSERM, U848, Villejuif, France
- Institut Gustave Roussy, Villejuif, France
- Faculté de Médecine, Université Paris-Sud 11, Villejuif, France
| | - Zahia Touat
- University of Versailles/St Quentin, PRES UniverSud Paris, CNRS UMR8159, Versailles, France
| | - Guido Kroemer
- INSERM, U848, Villejuif, France
- Institut Gustave Roussy, Villejuif, France
- Faculté de Médecine, Université Paris-Sud 11, Villejuif, France
- * E-mail: (CB); (GK)
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Abstract
Irrespective of the morphological features of end-stage cell death (that may be apoptotic, necrotic, autophagic, or mitotic), mitochondrial membrane permeabilization (MMP) is frequently the decisive event that delimits the frontier between survival and death. Thus mitochondrial membranes constitute the battleground on which opposing signals combat to seal the cell's fate. Local players that determine the propensity to MMP include the pro- and antiapoptotic members of the Bcl-2 family, proteins from the mitochondrialpermeability transition pore complex, as well as a plethora of interacting partners including mitochondrial lipids. Intermediate metabolites, redox processes, sphingolipids, ion gradients, transcription factors, as well as kinases and phosphatases link lethal and vital signals emanating from distinct subcellular compartments to mitochondria. Thus mitochondria integrate a variety of proapoptotic signals. Once MMP has been induced, it causes the release of catabolic hydrolases and activators of such enzymes (including those of caspases) from mitochondria. These catabolic enzymes as well as the cessation of the bioenergetic and redox functions of mitochondria finally lead to cell death, meaning that mitochondria coordinate the late stage of cellular demise. Pathological cell death induced by ischemia/reperfusion, intoxication with xenobiotics, neurodegenerative diseases, or viral infection also relies on MMP as a critical event. The inhibition of MMP constitutes an important strategy for the pharmaceutical prevention of unwarranted cell death. Conversely, induction of MMP in tumor cells constitutes the goal of anticancer chemotherapy.
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Affiliation(s)
- Guido Kroemer
- Institut Gustave Roussy, Institut National de la Santé et de la Recherche Médicale Unit "Apoptosis, Cancer and Immunity," Université de Paris-Sud XI, Villejuif, France
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Chami M, Oulès B, Paterlini-Bréchot P. Cytobiological consequences of calcium-signaling alterations induced by human viral proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1344-62. [PMID: 17059849 DOI: 10.1016/j.bbamcr.2006.09.025] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 09/13/2006] [Accepted: 09/15/2006] [Indexed: 01/25/2023]
Abstract
Since calcium-signaling regulates specific and fundamental cellular processes, it represents the ideal target of viral proteins, in order for the virus to control cellular functions and favour its persistence, multiplication and spread. A detailed analysis of reports focused on the impact of viral proteins on calcium-signaling has shown that virus-related elevations of cytosolic calcium levels allow increased viral protein expression (HIV-1, HSV-1/2), viral replication (HBx, enterovirus 2B, HTLV-1 p12(I), HHV-8, EBV), viral maturation (rotavirus), viral release (enterovirus 2B) and cell immortalization (EBV). Interestingly, virus-induced decreased cytosolic calcium levels have been found to be associated with inhibition of immune cells functions (HIV-1 Tat, HHV-8 K15, EBV LMP2A). Finally, several viral proteins are able to modulate intracellular calcium-signaling to control cell viability (HIV-1 Tat, HTLV-1 p13(II), HCV core, HBx, enterovirus 2B, HHV-8 K7). These data point out calcium-signaling as a key cellular target for viral infection and should stimulate further studies exploring new calcium-related therapeutic strategies.
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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. THE JOURNAL OF IMMUNOLOGY 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] [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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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] [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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Nicot C, Harrod RL, Ciminale V, Franchini G. Human T-cell leukemia/lymphoma virus type 1 nonstructural genes and their functions. Oncogene 2005; 24:6026-34. [PMID: 16155609 DOI: 10.1038/sj.onc.1208977] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human T-cell leukemia/lymphoma virus (HTLV) genome, in addition to the structural Gag and Env proteins and retroviral enzymes, carries a region at its 3' end originally designated pX. To date, we know that this region encodes two essential transcriptional and post-transcriptional positive regulators of viral expression, the Tax and Rex proteins, respectively (reviewed elsewhere in this issue). Here, we will review current knowledge of the functions of three additional proteins encoded in the pX region, p12I, p13II, and p30II.
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Affiliation(s)
- Christophe Nicot
- Department of Microbiology, University of Kansas Medical Center, Molecular Genetics, and Immunology, 3025 Wahl Hall West, 3901 Rainbow Boulevard, Kansas City, KS 66160-7420, USA
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