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Hokello J, Tyagi K, Owor RO, Sharma AL, Bhushan A, Daniel R, Tyagi M. New Insights into HIV Life Cycle, Th1/Th2 Shift during HIV Infection and Preferential Virus Infection of Th2 Cells: Implications of Early HIV Treatment Initiation and Care. Life (Basel) 2024; 14:104. [PMID: 38255719 PMCID: PMC10817636 DOI: 10.3390/life14010104] [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: 11/24/2023] [Revised: 01/05/2024] [Accepted: 01/07/2024] [Indexed: 01/24/2024] Open
Abstract
The theory of immune regulation involves a homeostatic balance between T-helper 1 (Th1) and T-helper 2 (Th2) responses. The Th1 and Th2 theories were introduced in 1986 as a result of studies in mice, whereby T-helper cell subsets were found to direct different immune response pathways. Subsequently, this hypothesis was extended to human immunity, with Th1 cells mediating cellular immunity to fight intracellular pathogens, while Th2 cells mediated humoral immunity to fight extracellular pathogens. Several disease conditions were later found to tilt the balance between Th1 and Th2 immune response pathways, including HIV infection, but the exact mechanism for the shift from Th1 to Th2 cells was poorly understood. This review provides new insights into the molecular biology of HIV, wherein the HIV life cycle is discussed in detail. Insights into the possible mechanism for the Th1 to Th2 shift during HIV infection and the preferential infection of Th2 cells during the late symptomatic stage of HIV disease are also discussed.
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Affiliation(s)
- Joseph Hokello
- Department of Biology, Faculty of Science and Education, Busitema University, Tororo P.O. Box 236, Uganda;
| | - Kratika Tyagi
- Department of Biotechnology, Banasthali Vidyapith, Jaipur 304022, India;
| | - Richard Oriko Owor
- Department of Chemistry, Faculty of Science and Education, Busitema University, Tororo P.O. Box 236, Uganda;
| | - Adhikarimayum Lakhikumar Sharma
- Center for Translational Medicine, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (A.L.S.); (R.D.)
| | - Alok Bhushan
- Department of Pharmaceutical Sciences, Jefferson College of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA;
| | - Rene Daniel
- Center for Translational Medicine, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (A.L.S.); (R.D.)
| | - Mudit Tyagi
- Center for Translational Medicine, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA; (A.L.S.); (R.D.)
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2
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Gotora PT, van der Sluis R, Williams ME. HIV-1 Tat amino acid residues that influence Tat-TAR binding affinity: a scoping review. BMC Infect Dis 2023; 23:164. [PMID: 36932337 PMCID: PMC10020771 DOI: 10.1186/s12879-023-08123-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/27/2023] [Indexed: 03/19/2023] Open
Abstract
HIV-1 remains a global health concern and to date, nearly 38 million people are living with HIV. The complexity of HIV-1 pathogenesis and its subsequent prevalence is influenced by several factors including the HIV-1 subtype. HIV-1 subtype variation extends to sequence variation in the amino acids of the HIV-1 viral proteins. Of particular interest is the transactivation of transcription (Tat) protein due to its key function in viral transcription. The Tat protein predominantly functions by binding to the transactivation response (TAR) RNA element to activate HIV-1 transcriptional elongation. Subtype-specific Tat protein sequence variation influences Tat-TAR binding affinity. Despite several studies investigating Tat-TAR binding, it is not clear which regions of the Tat protein and/or individual Tat amino acid residues may contribute to TAR binding affinity. We, therefore, conducted a scoping review on studies investigating Tat-TAR binding. We aimed to synthesize the published data to determine (1) the regions of the Tat protein that may be involved in TAR binding, (2) key Tat amino acids involved in TAR binding and (3) if Tat subtype-specific variation influences TAR binding. A total of thirteen studies met our inclusion criteria and the key findings were that (1) both N-terminal and C-terminal amino acids outside the basic domain (47-59) may be important in increasing Tat-TAR binding affinity, (2) substitution of the amino acids Lysine and Arginine (47-59) resulted in a reduction in binding affinity to TAR, and (3) none of the included studies have investigated Tat subtype-specific substitutions and therefore no commentary could be made regarding which subtype may have a higher Tat-TAR binding affinity. Future studies investigating Tat-TAR binding should therefore use full-length Tat proteins and compare subtype-specific variations. Studies of such a nature may help explain why we see differential pathogenesis and prevalence when comparing HIV-1 subtypes.
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3
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Szojka Z, Mótyán JA, Miczi M, Mahdi M, Tőzsér J. Y44A Mutation in the Acidic Domain of HIV-2 Tat Impairs Viral Reverse Transcription and LTR-Transactivation. Int J Mol Sci 2020; 21:ijms21165907. [PMID: 32824587 PMCID: PMC7460587 DOI: 10.3390/ijms21165907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/10/2020] [Accepted: 08/15/2020] [Indexed: 11/28/2022] Open
Abstract
HIV transactivator protein (Tat) plays a pivotal role in viral replication through modulation of cellular transcription factors and transactivation of viral genomic transcription. The effect of HIV-1 Tat on reverse transcription has long been described in the literature, however, that of HIV-2 is understudied. Sequence homology between Tat proteins of HIV-1 and 2 is estimated to be less than 30%, and the main difference lies within their N-terminal region. Here, we describe Y44A-inactivating mutation of HIV-2 Tat, studying its effect on capsid production, reverse transcription, and the efficiency of proviral transcription. Investigation of the mutation was performed using sequence- and structure-based in silico analysis and in vitro experiments. Our results indicate that the Y44A mutant HIV-2 Tat inhibited the activity and expression of RT (reverse transcriptase), in addition to diminishing Tat-dependent LTR (long terminal repeat) transactivation. These findings highlight the functional importance of the acidic domain of HIV-2 Tat in the regulation of reverse transcription and transactivation of the integrated provirions.
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Affiliation(s)
- Zsófia Szojka
- Laboratory of Retroviral Biochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (J.A.M.); (M.M.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - János András Mótyán
- Laboratory of Retroviral Biochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (J.A.M.); (M.M.)
| | - Márió Miczi
- Laboratory of Retroviral Biochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (J.A.M.); (M.M.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Mohamed Mahdi
- Laboratory of Retroviral Biochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (J.A.M.); (M.M.)
- Correspondence: (M.M.); (J.T.)
| | - József Tőzsér
- Laboratory of Retroviral Biochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.S.); (J.A.M.); (M.M.)
- Correspondence: (M.M.); (J.T.)
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4
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Khan N, Chen X, Geiger JD. Role of Divalent Cations in HIV-1 Replication and Pathogenicity. Viruses 2020; 12:E471. [PMID: 32326317 PMCID: PMC7232465 DOI: 10.3390/v12040471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/09/2020] [Accepted: 04/18/2020] [Indexed: 12/22/2022] Open
Abstract
Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.
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Affiliation(s)
| | | | - Jonathan D. Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA; (N.K.); (X.C.)
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5
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Mele AR, Marino J, Dampier W, Wigdahl B, Nonnemacher MR. HIV-1 Tat Length: Comparative and Functional Considerations. Front Microbiol 2020; 11:444. [PMID: 32265877 PMCID: PMC7105873 DOI: 10.3389/fmicb.2020.00444] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/02/2020] [Indexed: 12/22/2022] Open
Affiliation(s)
- Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Jamie Marino
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Will Dampier
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States.,School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
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6
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De Martini W, Rahman R, Ojegba E, Jungwirth E, Macias J, Ackerly F, Fowler M, Cottrell J, Chu T, Chang SL. Kinases: Understanding Their Role in HIV Infection. WORLD JOURNAL OF AIDS 2019; 9:142-160. [PMID: 32257606 PMCID: PMC7118713 DOI: 10.4236/wja.2019.93011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Antiviral drugs currently on the market primarily target proteins encoded by specific viruses. The drawback of these drugs is that they lack antiviral mechanisms that account for resistance or viral mutation. Thus, there is a pressing need for researchers to explore and investigate new therapeutic agents with other antiviral strategies. Viruses such as the human immunodeficiency virus (HIV) alter canonical signaling pathways to create a favorable biochemical environment for infectivity. We used Qiagen Ingenuity Pathway Analysis (IPA) software to review the function of several cellular kinases and the resulting perturbed signaling pathways during HIV infection such as NF-κB signaling. These host cellular kinases such as ADK, PKR, MAP3K11 are involved during HIV infection at various stages of the life cycle. Additionally IPA analysis indicated that these modified host cellular kinases are known to have interactions with each other especially AKT1, a serine/threonine kinase involved in multiple pathways. We present a list of cellular host kinases and other proteins that interact with these kinases. This approach to understanding the relationship between HIV infection and kinase activity may introduce new drug targets to arrest HIV infectivity.
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Affiliation(s)
- William De Martini
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Roksana Rahman
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Eduvie Ojegba
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Emily Jungwirth
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Jasmine Macias
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Frederick Ackerly
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Mia Fowler
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Jessica Cottrell
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Tinchun Chu
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Sulie L. Chang
- Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
- Institute of NeuroImmune Pharmacology, South Orange, NJ, USA
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7
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Spector C, Mele AR, Wigdahl B, Nonnemacher MR. Genetic variation and function of the HIV-1 Tat protein. Med Microbiol Immunol 2019; 208:131-169. [PMID: 30834965 DOI: 10.1007/s00430-019-00583-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 02/11/2019] [Indexed: 12/14/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes a transactivator of transcription (Tat) protein, which has several functions that promote viral replication, pathogenesis, and disease. Amino acid variation within Tat has been observed to alter the functional properties of Tat and, depending on the HIV-1 subtype, may produce Tat phenotypes differing from viruses' representative of each subtype and commonly used in in vivo and in vitro experimentation. The molecular properties of Tat allow for distinctive functional activities to be determined such as the subcellular localization and other intracellular and extracellular functional aspects of this important viral protein influenced by variation within the Tat sequence. Once Tat has been transported into the nucleus and becomes engaged in transactivation of the long terminal repeat (LTR), various Tat variants may differ in their capacity to activate viral transcription. Post-translational modification patterns based on these amino acid variations may alter interactions between Tat and host factors, which may positively or negatively affect this process. In addition, the ability of HIV-1 to utilize or not utilize the transactivation response (TAR) element within the LTR, based on genetic variation and cellular phenotype, adds a layer of complexity to the processes that govern Tat-mediated proviral DNA-driven transcription and replication. In contrast, cytoplasmic or extracellular localization of Tat may cause pathogenic effects in the form of altered cell activation, apoptosis, or neurotoxicity. Tat variants have been shown to differentially induce these processes, which may have implications for long-term HIV-1-infected patient care in the antiretroviral therapy era. Future studies concerning genetic variation of Tat with respect to function should focus on variants derived from HIV-1-infected individuals to efficiently guide Tat-targeted therapies and elucidate mechanisms of pathogenesis within the global patient population.
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Affiliation(s)
- Cassandra Spector
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA.
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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8
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van der Kuyl AC, Vink M, Zorgdrager F, Bakker M, Wymant C, Hall M, Gall A, Blanquart F, Berkhout B, Fraser C, Cornelissen M. The evolution of subtype B HIV-1 tat in the Netherlands during 1985-2012. Virus Res 2018; 250:51-64. [PMID: 29654800 DOI: 10.1016/j.virusres.2018.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 12/18/2022]
Abstract
For the production of viral genomic RNA, HIV-1 is dependent on an early viral protein, Tat, which is required for high-level transcription. The quantity of viral RNA detectable in blood of HIV-1 infected individuals varies dramatically, and a factor involved could be the efficiency of Tat protein variants to stimulate RNA transcription. HIV-1 virulence, measured by set-point viral load, has been observed to increase over time in the Netherlands and elsewhere. Investigation of tat gene evolution in clinical isolates could discover a role of Tat in this changing virulence. A dataset of 291 Dutch HIV-1 subtype B tat genes, derived from full-length HIV-1 genome sequences from samples obtained between 1985-2012, was used to analyse the evolution of Tat. Twenty-two patient-derived tat genes, and the control TatHXB2 were analysed for their capacity to stimulate expression of an LTR-luciferase reporter gene construct in diverse cell lines, as well as for their ability to complement a tat-defective HIV-1LAI clone. Analysis of 291 historical tat sequences from the Netherlands showed ample amino acid (aa) variation between isolates, although no specific mutations were selected for over time. Of note, however, the encoded protein varied its length over the years through the loss or gain of stop codons in the second exon. In transmission clusters, a selection against the shorter Tat86 ORF was apparent in favour of the more common Tat101 version, likely due to negative selection against Tat86 itself, although random drift, transmission bottlenecks, or linkage to other variants could also explain the observation. There was no correlation between Tat length and set-point viral load; however, the number of non-intermediate variants in our study was small. In addition, variation in the length of Tat did not significantly change its capacity to stimulate transcription. From 1985 till 2012, variation in the length of the HIV-1 subtype B tat gene is increasingly found in the Dutch epidemic. However, as Tat proteins did not differ significantly in their capacity to stimulate transcription elongation in vitro, the increased HIV-1 virulence seen in recent years could not be linked to an evolving viral Tat protein.
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Affiliation(s)
- Antoinette C van der Kuyl
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Monique Vink
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Fokla Zorgdrager
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Margreet Bakker
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Chris Wymant
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Matthew Hall
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Astrid Gall
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - François Blanquart
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
| | - Christophe Fraser
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, W21PG, United Kingdom; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Marion Cornelissen
- Laboratory of Experimental Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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9
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Gajanayaka N, O'Hara S, Konarski Y, Fernandes J, Muthumani K, Kozlowski M, Angel JB, Kumar A. HIV and HIV-Tat inhibit LPS-induced IL-27 production in human macrophages by distinct intracellular signaling pathways. J Leukoc Biol 2017; 102:925-939. [PMID: 28698313 DOI: 10.1189/jlb.4a0716-332rr] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 07/09/2017] [Accepted: 07/11/2017] [Indexed: 11/24/2022] Open
Abstract
Monocyte-derived Mϕs (MDMs) from HIV-infected patients and MDM infected in vitro with HIV exhibit a reduced ability to secrete various cytokines, including IL-12. Recently, IL-27, an IL-12 family cytokine, was shown to inhibit HIV replication in Mϕ. Whether HIV infection or HIV accessory protein(s) impact IL-27 production in Mϕs remains unknown. Herein, we show that in vitro HIV infection, as well as intracellular HIV-Tat (Tat) and Tat peptides, inhibit LPS-induced IL-27 production in human MDMs, suggesting impairment of the TLR4 signaling pathway. To understand the signaling pathways governing HIV or Tat-mediated inhibition of LPS-induced IL-27 production, we first demonstrated that p38 MAPK, PI3K, Src-homology region 2 domain-containing tyrosine phosphatase 1 (SHP-1), and Src kinases regulate LPS-induced IL-27 production in MDMs. Tat caused down-regulation of TNFR-associated factor (TRAF)-6 and inhibitor of apoptosis 1 (cIAP-1) and subsequently decreased phosphorylation of downstream PI3K and p38 MAPKs, which were implicated in LPS-induced IL-27 production. Whereas SHP-1 and Src kinases regulated LPS-induced IL-27 production, Tat did not inhibit these kinases, suggesting that they were not involved in Tat-mediated inhibition of LPS-induced IL-27 production. In contrast to Tat, in vitro HIV infection of MDM inhibited LPS-induced IL-27 production via inhibition of p38 MAPK activation. Overall, HIV and Tat inhibit LPS-induced IL-27 production in human macrophages via distinct mechanisms: Tat through the inhibition of cIAP-1-TRAF-6 and subsequent inhibition of PI3K and p38 MAPKs, whereas HIV through the inhibition of p38 MAPK activation.
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Affiliation(s)
- Niranjala Gajanayaka
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Shifawn O'Hara
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Yulia Konarski
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Jason Fernandes
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Kar Muthumani
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Maya Kozlowski
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Jonathan B Angel
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; and
| | - Ashok Kumar
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada; .,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.,Department Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
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10
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To V, Dzananovic E, McKenna SA, O’Neil J. The Dynamic Landscape of the Full-Length HIV-1 Transactivator of Transcription. Biochemistry 2016; 55:1314-25. [DOI: 10.1021/acs.biochem.5b01178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vu To
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Edis Dzananovic
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Sean A. McKenna
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Joe O’Neil
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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11
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Roy CN, Khandaker I, Furuse Y, Oshitani H. Molecular characterization of full-length Tat in HIV-1 subtypes B and C. Bioinformation 2015; 11:151-60. [PMID: 25914449 PMCID: PMC4403036 DOI: 10.6026/97320630011151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/02/2015] [Indexed: 12/13/2022] Open
Abstract
HIV-1Tat (trans-acting activator of transcription) plays essential roles in the replication through viral mRNA and genome transcription from the HIV-1 LTR promoter. However, Tat undergoes continuous amino acid substitutions. As a consequence, the virus escapes from host immunity indicating that genetic diversity of Tat protein in major HIV-1 subtypes is required to be continuously monitored. We analyzed available full-length HIV-1 sequences of subtypes B (n=493) and C (n=280) strains circulating worldwide. We observed 81% and 84% nucleotide sequence identities of HIV-1 Tat for subtypes B and C, respectively. Based on phylogenetic and mutation analyses, global diversity of subtype B was apparently higher compared to that of subtype C. Positively selected sites, such as positions Ser68 and Ser70 in both subtypes, were located in the Tat-transactivation responsive RNA (TAR) interaction domain. We also found positively selected sites in exon 2, such as positions Ser75, Pro77, Asp80, Pro81 and Ser87 for both subtypes. Our study provides useful information on the full-length HIV-1 Tat sequences in globally circulating strains.
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Affiliation(s)
- Chandra Nath Roy
- Department of Virology, Tohoku University Graduate School of Medicine, 2-1 Seiryomachi, Aoba-ku, Sendai city, Miyagi, Japan-9808575
| | - Irona Khandaker
- Department of Virology, Tohoku University Graduate School of Medicine, 2-1 Seiryomachi, Aoba-ku, Sendai city, Miyagi, Japan-9808575
| | - Yuki Furuse
- Department of Virology, Tohoku University Graduate School of Medicine, 2-1 Seiryomachi, Aoba-ku, Sendai city, Miyagi, Japan-9808575
| | - Hitoshi Oshitani
- Department of Virology, Tohoku University Graduate School of Medicine, 2-1 Seiryomachi, Aoba-ku, Sendai city, Miyagi, Japan-9808575
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12
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Dhamija N, Choudhary D, Ladha JS, Pillai B, Mitra D. Tat predominantly associates with host promoter elements in HIV-1-infected T-cells - regulatory basis of transcriptional repression of c-Rel. FEBS J 2014; 282:595-610. [PMID: 25472883 DOI: 10.1111/febs.13168] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/19/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022]
Abstract
HIV-1 Tat is a multifunctional regulatory protein that, in addition to its primary function of transactivating viral transcription, also tends to modulate cellular gene expression, for which the molecular mechanism remains to be clarified. We have reported earlier nuclear factor kappa B (NFκB) enhancer binding activity of Tat and proposed this DNA binding activity as a possible molecular basis for Tat-mediated regulation of cellular gene expression in infected cells. In the present study, we analyzed the genome-wide occupancy of Tat protein on host cell chromatin in HIV-1-infected T-cells to investigate a potential role of Tat on cellular gene expression. The results obtained identify a spectrum of binding sites of Tat protein on the chromatin and reveal that Tat is also recruited on a number of cellular gene promoters in HIV-1-infected T-cells, indicating its possible involvement in the regulation of gene expression of such cellular genes. Tat was identified as a repressor of one such validated gene, c-Rel, because it downregulates the expression of c-Rel in both Tat expressing and HIV-1-infected T-cells. The results also show that Tat downregulates c-Rel promoter activity by interacting with specific NFκB sites on the c-Rel promoter, thus providing a molecular basis of Tat-mediated regulation of cellular gene expression. Thus, in the present study, we have not only identified recruitment sites of Tat on the chromatin in HIV-1-infected T-cells, but also report for the first time that c-Rel is downregulated in HIV-1-infected cells specifically by interaction of Tat with NFκB binding sites on the promoter.
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Dichamp I, Abbas W, Kumar A, Di Martino V, Herbein G. Cellular activation and intracellular HCV load in peripheral blood monocytes isolated from HCV monoinfected and HIV-HCV coinfected patients. PLoS One 2014; 9:e96907. [PMID: 24809719 PMCID: PMC4014560 DOI: 10.1371/journal.pone.0096907] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/13/2014] [Indexed: 12/13/2022] Open
Abstract
Background During HCV infection, the activation status of peripheral blood monocytes and its impact on HCV replication are poorly understood. We hypothesized that a modified activation of peripheral blood monocytes in HIV-HCV coinfected compared to HCV monoinfected patients may contribute to different monocytes reservoirs of HCV replication. Methods We performed a case-control analysis involving HCV-infected patients with and without HIV coinfection. In peripheral blood mononuclear cells (PBMCs), peripheral blood lymphocytes (PBLs) and peripheral blood monocytes isolated from HCV monoinfected and HIV-HCV coinfected patients, intracellular HCV load and a marker of cellular activation, nuclear factor-kappaB (NF-κB) activation, were quantified using intracellular detection of HCV-core protein and electrophoretic mobility shift assay, respectively. Results Intracellular HCV loads were higher in monocytes isolated from HIV-HCV coinfected patients than in those of monoinfected patients. Among PBMCs isolated from HIV-HCV coinfected patients, intracellular HCV loads were higher in monocytes compared to PBLs. Cellular activation as measured by NF-κB activation was higher in monocytes isolated from HIV-HCV coinfected patients than in those of monoinfected patients. Conclusions Our results reveal the peripheral blood monocytes as an important extrahepatic reservoir for HCV in HIV-HCV coinfected patients and indicate a potential association between the activation state of monocytes and the size of the HCV reservoir in HIV-HCV coinfected patients.
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Affiliation(s)
- Isabelle Dichamp
- Pathogens and Inflammation Department, UPRES EA4266, SFR FED 4234, University of Franche-Comté, Besancon, France
- Department of Virology, CHRU Besançon, Besançon, France
| | - Wasim Abbas
- Pathogens and Inflammation Department, UPRES EA4266, SFR FED 4234, University of Franche-Comté, Besancon, France
- Department of Virology, CHRU Besançon, Besançon, France
| | - Amit Kumar
- Pathogens and Inflammation Department, UPRES EA4266, SFR FED 4234, University of Franche-Comté, Besancon, France
- Department of Virology, CHRU Besançon, Besançon, France
| | - Vincent Di Martino
- Pathogens and Inflammation Department, UPRES EA4266, SFR FED 4234, University of Franche-Comté, Besancon, France
- Department of Hepatology, CHRU Besançon, Besançon, France
| | - Georges Herbein
- Pathogens and Inflammation Department, UPRES EA4266, SFR FED 4234, University of Franche-Comté, Besancon, France
- Department of Virology, CHRU Besançon, Besançon, France
- * E-mail:
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Kukkonen S, Martinez-Viedma MDP, Kim N, Manrique M, Aldovini A. HIV-1 Tat second exon limits the extent of Tat-mediated modulation of interferon-stimulated genes in antigen presenting cells. Retrovirology 2014; 11:30. [PMID: 24742347 PMCID: PMC4036831 DOI: 10.1186/1742-4690-11-30] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/27/2014] [Indexed: 12/14/2022] Open
Abstract
Background We have shown that HIV-1 Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters is key to IFN-stimulated genes (ISG) activation in immature dendritic cells and macrophages. Results We evaluated how Tat alleles and mutants differ in cellular gene modulation of immature dendritic cells and monocyte-derived macrophages and what similarities this modulation has with that induced by interferons. The tested alleles and mutants modulated to different degrees ISG, without concomitant induction of interferons. The first exon TatSF21-72 and the minimal transactivator TatSF21-58, all modulated genes to a significantly greater extent than full-length wild type, two-exon Tat, indicating that Tat second exon is critical in reducing the innate response triggered by HIV-1 in these cells. Mutants with reduced LTR transactivation had a substantially reduced effect on host gene expression modulation than wild type TatSF2. However, the more potent LTR transactivator TatSF2A58T modulated ISG expression to a lower degree compared to TatSF2. A cellular gene modulation similar to that induced by Tat and Tat mutants in immature dendritic cells could be observed in monocyte-derived macrophages, with the most significant pathways affected by Tat being the same in both cell types. Tat expression in cells deleted of the type I IFN locus or receptor resulted in a gene modulation pattern similar to that induced in primary immature dendritic cells and monocyte-derived macrophages, excluding the involvement of type I IFNs in Tat-mediated gene modulation. ISG activation depends on Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters and a single exon Tat protein more strongly modulated the luciferase activity mediated by MAP2K3, MAP2K6, and IRF7 promoter sequences located 5′ of the RNA start site than the wild type two-exon Tat, while a cysteine and lysine Tat mutants, reduced in LTR transactivation, had negligible effects on these promoters. Chemical inhibition of CDK9 or Sp1 decreased Tat activation of MAP2K3-, MAP2K6-, and IRF7-mediated luciferase transcription. Conclusions Taken together, these data indicate that the second exon of Tat is critical to the containment of the innate response stimulated by Tat in antigen presenting cells and support a role for Tat in stimulating cellular transcription via its interaction with transcription factors present at promoters.
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Affiliation(s)
| | | | | | | | - Anna Aldovini
- Department of Pediatrics, Harvard Medical School, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
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15
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Abbas W, Herbein G. T-Cell Signaling in HIV-1 Infection. Open Virol J 2013; 7:57-71. [PMID: 23986795 PMCID: PMC3751038 DOI: 10.2174/1874357920130621001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 05/31/2013] [Accepted: 06/04/2013] [Indexed: 12/20/2022] Open
Abstract
HIV exploits the T-cell signaling network to gain access to downstream cellular components, which serves as effective tools to break the cellular barriers. Multiple host factors and their interaction with viral proteins contribute to the complexity of HIV-1 pathogenesis and disease progression. HIV-1 proteins gp120, Nef, Tat and Vpr alter the T-cell signaling pathways by activating multiple transcription factors including NF-ĸB, Sp1 and AP-1. HIV-1 evades the immune system by developing a multi-pronged strategy. Additionally, HIV-1 encoded proteins influence the apoptosis in the host cell favoring or blocking T-cell apoptosis. Thus, T-cell signaling hijacked by viral proteins accounts for both viral persistence and immune suppression during HIV-1 infection. Here, we summarize past and present studies on HIV-1 T-cell signaling with special focus on the possible role of T cells in facilitating viral infection and pathogenesis
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Affiliation(s)
- Wasim Abbas
- Department of Virology, Pathogens & Inflammation Laboratory, UPRES EA4266, SFR FED 4234, University of Franche-Comte, CHRU Besançon, F-25030 Besançon, France
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16
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tat Exon 1 exhibits functional diversity during HIV-1 subtype C primary infection. J Virol 2013; 87:5732-45. [PMID: 23487450 DOI: 10.1128/jvi.03297-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat is a mediator of viral transcription and is involved in the control of virus replication. However, associations between HIV-1 Tat diversity and functional effects during primary HIV-1 infection are still unclear. We estimated selection pressures in tat exon 1 using the mixed-effects model of evolution with 672 viral sequences generated from 20 patients infected with HIV-1 subtype C (HIV-1C) over 500 days postseroconversion. tat exon 1 residues 3, 4, 21, 24, 29, 39, and 68 were under positive selection, and we established that specific amino acid signature patterns were apparent in primary HIV-1C infection compared with chronic infection. We assessed the impact of these mutations on long terminal repeat (LTR) activity and found that Tat activity was negatively affected by the Ala(21) substitution identified in 13/20 (65%) of patients, which reduced LTR activity by 88% (± 1%) (P < 0.001). The greatest increase in Tat activity was seen with the Gln(35)/Lys(39) double mutant that resulted in an additional 49% (± 14%) production of LTR-driven luciferase (P = 0.012). There was a moderate positive correlation between Tat-mediated LTR activity and HIV-1 RNA in plasma (P = 0.026; r = 0.400) after 180 days postseroconversion that was reduced by 500 days postseroconversion (P = 0.043; r = 0.266). Although Tat activation of the LTR is not a strong predictor of these clinical variables, there are significant linear relationships between Tat transactivation and patients' plasma viral loads and CD4 counts, highlighting the complex interplay between Tat mutations in early HIV-1C infection.
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17
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López-Huertas MR, Mateos E, Sánchez Del Cojo M, Gómez-Esquer F, Díaz-Gil G, Rodríguez-Mora S, López JA, Calvo E, López-Campos G, Alcamí J, Coiras M. The presence of HIV-1 Tat protein second exon delays fas protein-mediated apoptosis in CD4+ T lymphocytes: a potential mechanism for persistent viral production. J Biol Chem 2013; 288:7626-7644. [PMID: 23364796 DOI: 10.1074/jbc.m112.408294] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIV-1 replication is efficiently controlled by the regulator protein Tat (101 amino acids) and codified by two exons, although the first exon (1-72 amino acids) is sufficient for this process. Tat can be released to the extracellular medium, acting as a soluble pro-apoptotic factor in neighboring cells. However, HIV-1-infected CD4(+) T lymphocytes show a higher resistance to apoptosis. We observed that the intracellular expression of Tat delayed FasL-mediated apoptosis in both peripheral blood lymphocytes and Jurkat cells, as it is an essential pathway to control T cell homeostasis during immune activation. Jurkat-Tat cells showed impairment in the activation of caspase-8, deficient release of mitochondrial cytochrome c, and delayed activation of both caspase-9 and -3. This protection was due to a profound deregulation of proteins that stabilized the mitochondrial membrane integrity, such as heat shock proteins, prohibitin, or nucleophosmin, as well as to the up-regulation of NF-κB-dependent anti-apoptotic proteins, such as BCL2, c-FLIPS, XIAP, and C-IAP2. These effects were observed in Jurkat expressing full-length Tat (Jurkat-Tat101) but not in Jurkat expressing the first exon of Tat (Jurkat-Tat72), proving that the second exon, and particularly the NF-κB-related motif ESKKKVE, was necessary for Tat-mediated protection against FasL apoptosis. Accordingly, the protection exerted by Tat was independent of its function as a regulator of both viral transcription and elongation. Moreover, these data proved that HIV-1 could have developed strategies to delay FasL-mediated apoptosis in infected CD4(+) T lymphocytes through the expression of Tat, thus favoring the persistent replication of HIV-1 in infected T cells.
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Affiliation(s)
- María Rosa López-Huertas
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Elena Mateos
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - María Sánchez Del Cojo
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Francisco Gómez-Esquer
- Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Madrid, Spain
| | - Gema Díaz-Gil
- Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Madrid, Spain
| | - Sara Rodríguez-Mora
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Juan Antonio López
- Unidad de Proteómica, Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain
| | - Enrique Calvo
- Unidad de Proteómica, Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain
| | - Guillermo López-Campos
- Health and Biomedical Informatics Research Unit, Melbourne Medical School, 3010 Melbourne, Australia
| | - José Alcamí
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain
| | - Mayte Coiras
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain.
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Baalwa J, Wang S, Parrish NF, Decker JM, Keele BF, Learn GH, Yue L, Ruzagira E, Ssemwanga D, Kamali A, Amornkul PN, Price MA, Kappes JC, Karita E, Kaleebu P, Sanders E, Gilmour J, Allen S, Hunter E, Montefiori DC, Haynes BF, Cormier E, Hahn BH, Shaw GM. Molecular identification, cloning and characterization of transmitted/founder HIV-1 subtype A, D and A/D infectious molecular clones. Virology 2012; 436:33-48. [PMID: 23123038 DOI: 10.1016/j.virol.2012.10.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/25/2012] [Accepted: 10/05/2012] [Indexed: 11/18/2022]
Abstract
We report the molecular identification, cloning and initial biological characterization of 12 full-length HIV-1 subtype A, D and A/D recombinant transmitted/founder (T/F) genomes. T/F genomes contained intact canonical open reading frames and all T/F viruses were replication competent in primary human T-cells, although subtype D virus replication was more efficient (p<0.05). All 12 viruses utilized CCR5 but not CXCR4 as a co-receptor for entry and exhibited a neutralization profile typical of tier 2 primary virus strains, with significant differences observed between subtype A and D viruses with respect to sensitivity to monoclonal antibodies VRC01, PG9 and PG16 and polyclonal subtype C anti-HIV IgG (p<0.05 for each). The present report doubles the number of T/F HIV-1 clones available for pathogenesis and vaccine research and extends their representation to include subtypes A, B, C and D.
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Affiliation(s)
- Joshua Baalwa
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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19
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Impact of Tat Genetic Variation on HIV-1 Disease. Adv Virol 2012; 2012:123605. [PMID: 22899925 PMCID: PMC3414192 DOI: 10.1155/2012/123605] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) promoter or long-terminal repeat (LTR) regulates viral gene expression by interacting with multiple viral and host factors. The viral transactivator protein Tat plays an important role in transcriptional activation of HIV-1 gene expression. Functional domains of Tat and its interaction with transactivation response element RNA and cellular transcription factors have been examined. Genetic variation within tat of different HIV-1 subtypes has been shown to affect the interaction of the viral transactivator with cellular and/or viral proteins, influencing the overall level of transcriptional activation as well as its action as a neurotoxic protein. Consequently, the genetic variability within tat may impact the molecular architecture of functional domains of the Tat protein that may impact HIV pathogenesis and disease. Tat as a therapeutic target for anti-HIV drugs has also been discussed.
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20
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Wollebo HS, Melis S, Khalili K, Safak M, White MK. Cooperative roles of NF-κB and NFAT4 in polyomavirus JC regulation at the KB control element. Virology 2012; 432:146-54. [PMID: 22749879 DOI: 10.1016/j.virol.2012.06.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 03/15/2012] [Accepted: 06/05/2012] [Indexed: 11/29/2022]
Abstract
The human polyomavirus JC (JCV) is the causative agent of the CNS demyelinating disease progressive multifocal leukoencephalopathy (PML). Infection by JCV is extremely common and after primary infection, JCV persists in a latent state. However, PML is a very rare disease suggesting that the virus is tightly regulated. Previously, we showed that NF-κB and C/EBPβ regulate the JCV early and late promoters via a DNA control element, KB, which also mediates the stimulatory effects of proinflammatory cytokines such as TNF-α on JCV gene expression. Other studies have implicated NFAT4 in JCV regulation. We now report that NFAT4 and NF-κB interact at the KB element to co-operatively activate both JCV early and late transcription and viral DNA replication. This interplay is inhibited by C/EBPβ and by agents that block the calcineurin/NFAT signaling pathway. The importance of these events in the regulation of JCV latency and reactivation is discussed.
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Affiliation(s)
- Hassen S Wollebo
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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21
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Honda JR, Shang S, Shanley CA, Caraway ML, Henao-Tamayo M, Chan ED, Basaraba RJ, Orme IM, Ordway DJ, Flores SC. Immune Responses of HIV-1 Tat Transgenic Mice to Mycobacterium Tuberculosis W-Beijing SA161. Open AIDS J 2011; 5:86-95. [PMID: 22046211 PMCID: PMC3204420 DOI: 10.2174/1874613601105010086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/22/2011] [Accepted: 05/11/2011] [Indexed: 11/30/2022] Open
Abstract
Background: Mycobacterium tuberculosis remains among the leading causes of death from an infectious agent in the world and exacerbates disease caused by the human immunodeficiency virus (HIV). HIV infected individuals are prone to lung infections by a variety of microbial pathogens, including M. tuberculosis. While the destruction of the adaptive immune response by HIV is well understood, the actual pathogenesis of tuberculosis in co-infected individuals remains unclear. Tat is an HIV protein essential for efficient viral gene transcription, is secreted from infected cells, and is known to influence a variety of host inflammatory responses. We hypothesize Tat contributes to pathophysiological changes in the lung microenvironment, resulting in impaired host immune responses to infection by M. tuberculosis. Results: Herein, we show transgenic mice that express Tat by lung alveolar cells are more susceptible than non-transgenic control littermates to a low-dose aerosol infection of M. tuberculosis W-Beijing SA161. Survival assays demonstrate accelerated mortality rates of the Tat transgenic mice compared to non-transgenics. Tat transgenic mice also showed poorly organized lung granulomata-like lesions. Analysis of the host immune response using quantitative RT-PCR, flow cytometry for surface markers, and intracellular cytokine staining showed increased expression of pro-inflammatory cytokines in the lungs, increased numbers of cells expressing ICAM1, increased numbers of CD4+CD25+Foxp3+ T regulatory cells, and IL-4 producing CD4+ T cells in the Tat transgenics compared to infected non-tg mice. Conclusions: Our data show quantitative differences in the inflammatory response to the SA161 clinical isolate of M. tuberculosis W-Beijing between Tat transgenic and non-transgenic mice, suggesting Tat contributes to the pathogenesis of tuberculosis.
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Affiliation(s)
- Jennifer R Honda
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, 80045, USA
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22
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Ashraf T, Ronaldson PT, Persidsky Y, Bendayan R. Regulation of P-glycoprotein by human immunodeficiency virus-1 in primary cultures of human fetal astrocytes. J Neurosci Res 2011; 89:1773-82. [PMID: 21826700 DOI: 10.1002/jnr.22720] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/28/2011] [Accepted: 05/19/2011] [Indexed: 01/04/2023]
Abstract
P-glycoprotein (P-gp), a drug efflux pump, is known to alter the bioavailability of antiretroviral drugs at several sites, including the brain. We have previously shown that human immunodeficiency virus-1 (HIV-1) glycoprotein 120 (gp120) induces proinflammatory cytokine secretion and decreases P-gp functional expression in rat astrocytes, a cellular reservoir of HIV-1. However, whether P-gp is regulated in a similar way in human astrocytes is unknown. This study investigates the regulation of P-gp in an in vitro model of gp120-triggered human fetal astrocytes (HFAs). In this system, elevated levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α were detected in culture supernatants. Pretreatment with CCR5 neutralizing antibody attenuated cytokine secretion, suggesting that gp120-CCR5 interaction mediated cytokine production. Treatment with gp120 (R5-tropic) resulted in reduced P-gp expression (64%) and function as determined by increased (1.6-fold) cellular accumulation of [(3) H]digoxin, a P-gp substrate. Exposure to R5 or R5/X4-tropic viral isolates led to a downregulation in P-gp expression (75% or 90%, respectively), and treatment with IL-6 also showed lower P-gp expression (50%). Moreover, IL-6 neutralizing antibody blocked gp120-mediated P-gp downregulation, suggesting that IL-6 is a key modulator of P-gp. Gp120- or IL-6-mediated downregulation of P-gp was attenuated by SN50 (a nuclear factor-κB [NF-κB] inhibitor), suggesting involvement of NF-κB signaling in P-gp regulation. Our results suggest that, similarly to the case with rodent astrocytes, pathophysiological stressors associated with brain HIV-1 infection have a downregulatory effect on P-gp functional expression in human astrocytes, which may ultimately result in altered antiretroviral drug accumulation within brain parenchyma.
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Affiliation(s)
- Tamima Ashraf
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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23
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Strazza M, Pirrone V, Wigdahl B, Nonnemacher MR. Breaking down the barrier: the effects of HIV-1 on the blood-brain barrier. Brain Res 2011; 1399:96-115. [PMID: 21641584 DOI: 10.1016/j.brainres.2011.05.015] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 05/06/2011] [Accepted: 05/07/2011] [Indexed: 01/13/2023]
Abstract
Human immunodeficiency virus type 1 (HIV-1) primarily infects CD4(+) T cells and cells of the monocyte-macrophage lineage, resulting in immunodeficiency in an infected patient. Along with this immune deficiency, HIV-1 has been linked to a number of neurological symptoms in the absence of opportunistic infections or other co-morbidities, suggesting that HIV-1 is able to cross the blood-brain barrier (BBB), enter the central nervous system (CNS), and cause neurocognitive impairment. HIV-1-infected monocyte-macrophages traverse the BBB and enter the CNS throughout the course of HIV-1 disease. Once in the brain, both free virus and virus-infected cells are able to infect neighboring resident microglia and astrocytes and possibly other cell types. HIV-1-infected cells in both the periphery and the CNS give rise to elevated levels of viral proteins, including gp120, Tat, and Nef, and of host inflammatory mediators such as cytokines and chemokines. It has been shown that the viral proteins may act alone or in concert with host cytokines and chemokines, affecting the integrity of the BBB. The pathological end point of these interactions may facilitate a positive feedback loop resulting in increased penetration of HIV into the CNS. It is proposed in this review that the dysregulation of the BBB during and after neuroinvasion is a critical component of the neuropathogenic process and that dysregulation of this protective barrier is caused by a combination of viral and host factors including secreted viral proteins, components of the inflammatory process, the aging process, therapeutics, and drug or alcohol abuse.
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Affiliation(s)
- Marianne Strazza
- Department of Microbiology and Immunology, and Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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McQueen P, Donald LJ, Vo TN, Nguyen DH, Griffiths H, Shojania S, Standing KG, O'Neil JD. Tat peptide-calmodulin binding studies and bioinformatics of HIV-1 protein-calmodulin interactions. Proteins 2011; 79:2233-46. [DOI: 10.1002/prot.23048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 03/18/2011] [Accepted: 03/22/2011] [Indexed: 01/08/2023]
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Johri MK, Mishra R, Chhatbar C, Unni SK, Singh SK. Tits and bits of HIV Tat protein. Expert Opin Biol Ther 2011; 11:269-83. [PMID: 21204735 DOI: 10.1517/14712598.2011.546339] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION HIV-Tat protein displays an array of functions that are essential for HIV replication. The structural flexibility of Tat protein has been regarded as one of the unique features responsible for sustaining diverse functions, from facilitated membrane-crossing ability to strong affinity for RNA binding. AREAS COVERED RNA binding ability and presence of multiple interacting domains in the same protein are very important properties of HIV-Tat protein. Tat protein has shown great ability to influence cellular and viral gene expression. We discuss the functions of HIV Tat protein, describing its structural significance, secretion and uptake of HIV Tat protein by immune cells, post-translational modifications and role of HIV Tat protein in HIV pathogenesis. EXPERT OPINION Perturbation in expression of many cytokines and chemokines by HIV-Tat protein exhibits downstream immune suppressive function as well as activation of several apoptotic genes. This explains the massive death of immune cells due to bystander effect of HIV Tat protein among HIV-infected patients.
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Affiliation(s)
- Manish K Johri
- Laboratory of Neurovirology & Inflammation Biology, Section of Infectious Diseases, Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad-500007, (A.P), India
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26
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Khiati A, Chaloin O, Muller S, Tardieu M, Horellou P. Induction of monocyte chemoattractant protein-1 (MCP-1/CCL2) gene expression by human immunodeficiency virus-1 Tat in human astrocytes is CDK9 dependent. J Neurovirol 2010; 16:150-67. [PMID: 20370601 DOI: 10.3109/13550281003735691] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) invades the brain early in infection and may cause HIV-associated dementia (HAD), which is characterized by reactive astrocytes, and macrophage and T-cell infiltrates. HIV-1 Tat protein is thought to contribute to HAD by transactivating host genes, such as that encoding monocyte chemoattractant protein-1 (MCP-1/CCL2), although its mechanisms of action are not fully understood. We investigated the molecular pathways involved in Tat-induced MCP-1/CCL2 gene expression in human astrocytes. We found that Tat induced MCP-1/CCL2 synthesis in human astrocytes infected with a lentivirus carrying the gene encoding Tat or treated with a biologically active synthetic Tat protein. The induction of MCP-1/CCL2 was independent of the nuclear factor kappaB (NF-kappaB) classical pathway, but was significantly inhibited by specific cyclin-dependent kinase 9 (cdk9) inhibitors, such as a dominant-negative mutant or siRNA. By contrast, broader-spectrum cdk inhibitors, such as roscovitine, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB), and flavopiridol, inhibited MCP-1/CCL2 induction by Tat. We also analyzed the effects of roscovitine, DRB, and flavopiridol on Tat-induced HIV-1 long terminal repeat (LTR) expression following the infection of astrocytes and HeLa cells. Astrocytes showed no inhibition by roscovitine, 59% inhibition by DRB, and 80% inhibition by flavopiridol. In control HeLa cells, high levels of inhibition were observed with roscovitine, DRB, and flavopiridol. We have ascertained the direct implication of cdk9 in Tat-induced MCP-1 expression by performing ChIP assay. These results demonstrate that cdk9 is involved in Tat-induced HIV-1 LTR, MCP-1/CCL2 gene expression.
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Affiliation(s)
- Abdelkader Khiati
- INSERM U802 and Université Paris-Sud 11, Faculté de médecine Paris-Sud, Le Kremlin-Bicêtre, France
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Role of HIV-1 Tat in AIDS pathogenesis: its effects on cytokine dysregulation and contributions to the pathogenesis of opportunistic infection. AIDS 2010; 24:1609-23. [PMID: 20588103 DOI: 10.1097/qad.0b013e32833ac6a0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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López-Huertas MR, Callejas S, Abia D, Mateos E, Dopazo A, Alcamí J, Coiras M. Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon. Nucleic Acids Res 2010; 38:3287-307. [PMID: 20139419 PMCID: PMC2879518 DOI: 10.1093/nar/gkq037] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) regulator Tat is essential for viral replication because it achieves complete elongation of viral transcripts. Tat can be released to the extracellular space and taken up by adjacent cells, exerting profound cytoskeleton rearrangements that lead to apoptosis. In contrast, intracellular Tat has been described as protector from apoptosis. Tat gene is composed by two coding exons that yield a protein of 101 amino acids (aa). First exon (1–72aa) is sufficient for viral transcript elongation and second exon (73–101 aa) appears to contribute to non-transcriptional functions. We observed that Jurkat cells stably expressing intracellular Tat101 showed gene expression deregulation 4-fold higher than cells expressing Tat72. Functional experiments were performed to evaluate the effect of this deregulation. First, NF-κB-, NF-AT- and Sp1-dependent transcriptional activities were greatly enhanced in Jurkat-Tat101, whereas Tat72 induced milder but efficient activation. Second, cytoskeleton-related functions as cell morphology, proliferation, chemotaxis, polarization and actin polymerization were deeply altered in Jurkat-Tat101, but not in Jurkat-Tat72. Finally, expression of several cell surface receptors was dramatically impaired by intracellular Tat101 but not by Tat72. Consequently, these modifications were greatly dependent on Tat second exon and they could be related to the anergy observed in HIV-1-infected T cells.
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Affiliation(s)
- M R López-Huertas
- AIDS Immunopathology Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
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Caputo A, Gavioli R, Bellino S, Longo O, Tripiciano A, Francavilla V, Sgadari C, Paniccia G, Titti F, Cafaro A, Ferrantelli F, Monini P, Ensoli F, Ensoli B. HIV-1 Tat-based vaccines: an overview and perspectives in the field of HIV/AIDS vaccine development. Int Rev Immunol 2009; 28:285-334. [PMID: 19811313 DOI: 10.1080/08830180903013026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The HIV epidemic continues to represent one of the major problems worldwide, particularly in the Asia and Sub-Saharan regions of the world, with social and economical devastating effects. Although antiretroviral drugs have had a dramatically beneficial impact on HIV-infected individuals that have access to treatment, it has had a negligible impact on the global epidemic. Hence, the inexorable spreading of the HIV pandemic and the increasing deaths from AIDS, especially in developing countries, underscore the urgency for an effective vaccine against HIV/AIDS. However, the generation of such a vaccine has turned out to be extremely challenging. Here we provide an overview on the rationale for the use of non-structural HIV proteins, such as the Tat protein, alone or in combination with other HIV early and late structural HIV antigens, as novel, promising preventative and therapeutic HIV/AIDS vaccine strategies.
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Affiliation(s)
- Antonella Caputo
- Department of Histology, Microbiology and Medical Biotechnology, University of Padova, Padova, Italy
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Romani B, Engelbrecht S, Glashoff RH. Functions of Tat: the versatile protein of human immunodeficiency virus type 1. J Gen Virol 2009; 91:1-12. [PMID: 19812265 DOI: 10.1099/vir.0.016303-0] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat is a multifunctional protein that contributes to several pathological symptoms of HIV-1 infection as well as playing a critical role in virus replication. Tat is a robust transactivating protein that induces a variety of effects by altering the expression levels of cellular and viral genes. The functions of Tat are therefore primarily related to its role in modulation of gene expression. In this review the functions of HIV-1 Tat that have been well documented, as well as a number of novel functions that have been proposed for this protein, are discussed. Since some of the functions of Tat vary in different cell types in a concentration-dependent manner and because Tat sometimes exerts the same activity through different pathways, study of this protein has at times yielded conflicting and controversial results. Due to its pivotal role in viral replication and in disease pathogenesis, Tat and the cellular pathways targeted by Tat are potential targets for new anti-HIV drugs.
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Affiliation(s)
- Bizhan Romani
- Division of Medical Virology, Department of Pathology, University of Stellenbosch, Tygerberg 7505, South Africa.
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Caputo A, Gavioli R, Bellino S, Longo O, Tripiciano A, Francavilla V, Sgadari C, Paniccia G, Titti F, Cafaro A, Ferrantelli F, Monini P, Ensoli F, Ensoli B. HIV-1 Tat-Based Vaccines: An Overview and Perspectives in the Field of HIV/AIDS Vaccine Development. Int Rev Immunol 2009. [DOI: 10.1080/08830180903013026 10.1080/08830180903013026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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