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D'Orso I. The HIV-1 Transcriptional Program: From Initiation to Elongation Control. J Mol Biol 2024:168690. [PMID: 38936695 DOI: 10.1016/j.jmb.2024.168690] [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: 04/01/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024]
Abstract
A large body of work in the last four decades has revealed the key pillars of HIV-1 transcription control at the initiation and elongation steps. Here, I provide a recount of this collective knowledge starting with the genomic elements (DNA and nascent TAR RNA stem-loop) and transcription factors (cellular and the viral transactivator Tat), and later transitioning to the assembly and regulation of transcription initiation and elongation complexes, and the role of chromatin structure. Compelling evidence support a core HIV-1 transcriptional program regulated by the sequential and concerted action of cellular transcription factors and Tat to promote initiation and sustain elongation, highlighting the efficiency of a small virus to take over its host to produce the high levels of transcription required for viral replication. I summarize new advances including the use of CRISPR-Cas9, genetic tools for acute factor depletion, and imaging to study transcriptional dynamics, bursting and the progression through the multiple phases of the transcriptional cycle. Finally, I describe current challenges to future major advances and discuss areas that deserve more attention to both bolster our basic knowledge of the core HIV-1 transcriptional program and open up new therapeutic opportunities.
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Affiliation(s)
- Iván D'Orso
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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2
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Ashokkumar M, Mei W, Peterson JJ, Harigaya Y, Murdoch DM, Margolis DM, Kornfein C, Oesterling A, Guo Z, Rudin CD, Jiang Y, Browne EP. Integrated Single-cell Multiomic Analysis of HIV Latency Reversal Reveals Novel Regulators of Viral Reactivation. GENOMICS, PROTEOMICS & BIOINFORMATICS 2024; 22:qzae003. [PMID: 38902848 PMCID: PMC11189801 DOI: 10.1093/gpbjnl/qzae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 10/19/2023] [Indexed: 06/22/2024]
Abstract
Despite the success of antiretroviral therapy, human immunodeficiency virus (HIV) cannot be cured because of a reservoir of latently infected cells that evades therapy. To understand the mechanisms of HIV latency, we employed an integrated single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin with sequencing (scATAC-seq) approach to simultaneously profile the transcriptomic and epigenomic characteristics of ∼ 125,000 latently infected primary CD4+ T cells after reactivation using three different latency reversing agents. Differentially expressed genes and differentially accessible motifs were used to examine transcriptional pathways and transcription factor (TF) activities across the cell population. We identified cellular transcripts and TFs whose expression/activity was correlated with viral reactivation and demonstrated that a machine learning model trained on these data was 75%-79% accurate at predicting viral reactivation. Finally, we validated the role of two candidate HIV-regulating factors, FOXP1 and GATA3, in viral transcription. These data demonstrate the power of integrated multimodal single-cell analysis to uncover novel relationships between host cell factors and HIV latency.
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Affiliation(s)
- Manickam Ashokkumar
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Wenwen Mei
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jackson J Peterson
- HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yuriko Harigaya
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David M Murdoch
- Department of Medicine, Duke University, Durham, NC 27708, USA
| | - David M Margolis
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Caleb Kornfein
- Department of Computer Science, Duke University, Durham, NC 27708, USA
| | - Alex Oesterling
- Department of Computer Science, Duke University, Durham, NC 27708, USA
| | - Zhicheng Guo
- Department of Computer Science, Duke University, Durham, NC 27708, USA
| | - Cynthia D Rudin
- Department of Computer Science, Duke University, Durham, NC 27708, USA
| | - Yuchao Jiang
- Department of Statistics, Texas A&M University, College Station, TX 77843, USA
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Edward P Browne
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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3
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Crespo R, Ne E, Reinders J, Meier JI, Li C, Jansen S, Górska A, Koçer S, Kan TW, Doff W, Dekkers D, Demmers J, Palstra RJ, Rao S, Mahmoudi T. PCID2 dysregulates transcription and viral RNA processing to promote HIV-1 latency. iScience 2024; 27:109152. [PMID: 38384833 PMCID: PMC10879814 DOI: 10.1016/j.isci.2024.109152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 12/06/2023] [Accepted: 02/01/2024] [Indexed: 02/23/2024] Open
Abstract
HIV-1 latency results from tightly regulated molecular processes that act at distinct steps of HIV-1 gene expression. Here, we characterize PCI domain-containing 2 (PCID2) protein, a subunit of the transcription and export complex 2 (TREX2) complex, to enforce transcriptional repression and post-transcriptional blocks to HIV-1 gene expression during latency. PCID2 bound the latent HIV-1 LTR (long terminal repeat) and repressed transcription initiation during latency. Depletion of PCID2 remodeled the chromatin landscape at the HIV-1 promoter and resulted in transcriptional activation and latency reversal. Immunoprecipitation coupled to mass spectrometry identified PCID2-interacting proteins to include negative viral RNA (vRNA) splicing regulators, and PCID2 depletion resulted in over-splicing of intron-containing vRNA in cell lines and primary cells obtained from PWH. MCM3AP and DSS1, two other RNA-binding TREX2 complex subunits, also inhibit transcription initiation and vRNA alternative splicing during latency. Thus, PCID2 is a novel HIV-1 latency-promoting factor, which in context of the TREX2 sub-complex PCID2-DSS1-MCM3AP blocks transcription and dysregulates vRNA processing.
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Affiliation(s)
- Raquel Crespo
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Enrico Ne
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Julian Reinders
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Jenny I.J. Meier
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Chengcheng Li
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Sanne Jansen
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Alicja Górska
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Selin Koçer
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Tsung Wai Kan
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
- Department of Pathology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Department of Urology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Wouter Doff
- Proteomics Center, Erasmus University Medical Center, Ee679a PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Dick Dekkers
- Proteomics Center, Erasmus University Medical Center, Ee679a PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Jeroen Demmers
- Proteomics Center, Erasmus University Medical Center, Ee679a PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Robert-Jan Palstra
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
- Department of Pathology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Department of Urology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Shringar Rao
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, Ee622 PO Box 2040, 3000 CA Rotterdam, the Netherlands
- Department of Pathology, Erasmus University Medical Center, Rotterdam, the Netherlands
- Department of Urology, Erasmus University Medical Center, Rotterdam, the Netherlands
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4
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Rausch JW, Parvez S, Pathak S, Capoferri AA, Kearney MF. HIV Expression in Infected T Cell Clones. Viruses 2024; 16:108. [PMID: 38257808 PMCID: PMC10820123 DOI: 10.3390/v16010108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/24/2024] Open
Abstract
The principal barrier to an HIV-1 cure is the persistence of infected cells harboring replication-competent proviruses despite antiretroviral therapy (ART). HIV-1 transcriptional suppression, referred to as viral latency, is foremost among persistence determinants, as it allows infected cells to evade the cytopathic effects of virion production and killing by cytotoxic T lymphocytes (CTL) and other immune factors. HIV-1 persistence is also governed by cellular proliferation, an innate and essential capacity of CD4+ T cells that both sustains cell populations over time and enables a robust directed response to immunological threats. However, when HIV-1 infects CD4+ T cells, this capacity for proliferation can enable surreptitious HIV-1 propagation without the deleterious effects of viral gene expression in latently infected cells. Over time on ART, the HIV-1 reservoir is shaped by both persistence determinants, with selective forces most often favoring clonally expanded infected cell populations harboring transcriptionally quiescent proviruses. Moreover, if HIV latency is incomplete or sporadically reversed in clonal infected cell populations that are replenished faster than they are depleted, such populations could both persist indefinitely and contribute to low-level persistent viremia during ART and viremic rebound if treatment is withdrawn. In this review, select genetic, epigenetic, cellular, and immunological determinants of viral transcriptional suppression and clonal expansion of HIV-1 reservoir T cells, interdependencies among these determinants, and implications for HIV-1 persistence will be presented and discussed.
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Affiliation(s)
- Jason W. Rausch
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; (S.P.); (S.P.); (A.A.C.); (M.F.K.)
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5
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Madlala P, Mkhize Z, Naicker S, Khathi SP, Maikoo S, Gopee K, Dong KL, Ndung'u T. Genetic variation of the HIV-1 subtype C transmitted/founder viruses long terminal repeat elements and the impact on transcription activation potential and clinical disease outcomes. PLoS Pathog 2023; 19:e1011194. [PMID: 37307292 DOI: 10.1371/journal.ppat.1011194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/04/2023] [Indexed: 06/14/2023] Open
Abstract
A genetic bottleneck is a hallmark of HIV-1 transmission such that only very few viral strains, termed transmitted/founder (T/F) variants establish infection in a newly infected host. Phenotypic characteristics of these variants may determine the subsequent course of disease. The HIV-1 5' long terminal repeat (LTR) promoter drives viral gene transcription and is genetically identical to the 3' LTR. We hypothesized that HIV-1 subtype C (HIV-1C) T/F virus LTR genetic variation is a determinant of transcriptional activation potential and clinical disease outcome. The 3'LTR was amplified from plasma samples of 41 study participants acutely infected with HIV-1C (Fiebig stages I and V/VI). Paired longitudinal samples were also available at one year post-infection for 31 of the 41 participants. 3' LTR amplicons were cloned into a pGL3-basic luciferase expression vector, and transfected alone or together with Transactivator of transcription (tat) into Jurkat cells in the absence or presence of cell activators (TNF-α, PMA, Prostratin and SAHA). Inter-patient T/F LTR sequence diversity was 5.7% (Renge: 2-12) with subsequent intrahost viral evolution observed in 48.4% of the participants analyzed at 12 months post-infection. T/F LTR variants exhibited differential basal transcriptional activity, with significantly higher Tat-mediated transcriptional activity compared to basal (p<0.001). Basal and Tat-mediated T/F LTR transcriptional activity showed significant positive correlation with contemporaneous viral loads and negative correlation with CD4 T cell counts (p<0.05) during acute infection respectively. Furthermore, Tat-mediated T/F LTR transcriptional activity significanly correlated positively with viral load set point and viral load; and negatively with CD4 T cell counts at one year post infection (all p<0.05). Lastly, PMA, Prostratin, TNF-α and SAHA cell stimulation resulted in enhanced yet heterologous transcriptional activation of different T/F LTR variants. Our data suggest that T/F LTR variants may influence viral transcriptional activity, disease outcomes and sensitivity to cell activation, with potential implications for therapeutic interventions.
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Affiliation(s)
- Paradise Madlala
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Zakithi Mkhize
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Shamara Naicker
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Samukelisiwe P Khathi
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Shreyal Maikoo
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Kasmira Gopee
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Krista L Dong
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, Massachusetts, United States of America
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, The Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, Massachusetts, United States of America
- Africa Health Research Institute (AHRI), Durban, South Africa
- Division of Infection and Immunity, University College London, London, United Kingdom
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6
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Collora JA, Ho YC. Integration site-dependent HIV-1 promoter activity shapes host chromatin conformation. Genome Res 2023; 33:891-906. [PMID: 37295842 PMCID: PMC10519397 DOI: 10.1101/gr.277698.123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
HIV-1 integration introduces ectopic transcription factor binding sites into host chromatin. We postulate that the integrated provirus serves as an ectopic enhancer that recruits additional transcription factors to the integration locus, increases chromatin accessibility, changes 3D chromatin interactions, and enhances both retroviral and host gene expression. We used four well-characterized HIV-1-infected cell line clones having unique integration sites and low to high levels of HIV-1 expression. Using single-cell DOGMA-seq, which captured the heterogeneity of HIV-1 expression and host chromatin accessibility, we found that HIV-1 transcription correlated with HIV-1 accessibility and host chromatin accessibility. HIV-1 integration increased local host chromatin accessibility within an ∼5- to 30-kb distance. CRISPRa- and CRISPRi-mediated HIV-1 promoter activation and inhibition confirmed integration site-dependent HIV-1-driven changes of host chromatin accessibility. HIV-1 did not drive chromatin confirmation changes at the genomic level (by Hi-C) or the enhancer connectome (by H3K27ac HiChIP). Using 4C-seq to interrogate HIV-1-chromatin interactions, we found that HIV-1 interacted with host chromatin ∼100-300 kb from the integration site. By identifying chromatin regions having both increased transcription factor activity (by ATAC-seq) and HIV-1-chromatin interaction (by 4C-seq), we identified enrichment of ETS, RUNT, and ZNF-family transcription factor binding that may mediate HIV-1-host chromatin interactions. Our study has found that HIV-1 promoter activity increases host chromatin accessibility, and HIV-1 interacted with host chromatin within the existing chromatin boundaries in an integration site-dependent manner.
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Affiliation(s)
- Jack A Collora
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06519, USA
| | - Ya-Chi Ho
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06519, USA
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Ling L, Leda AR, Begum N, Spagnuolo RA, Wahl A, Garcia JV, Valente ST. Loss of In Vivo Replication Fitness of HIV-1 Variants Resistant to the Tat Inhibitor, dCA. Viruses 2023; 15:950. [PMID: 37112931 PMCID: PMC10146675 DOI: 10.3390/v15040950] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/29/2023] [Accepted: 04/01/2023] [Indexed: 04/29/2023] Open
Abstract
HIV resistance to the Tat inhibitor didehydro-cortistatin A (dCA) in vitro correlates with higher levels of Tat-independent viral transcription and a seeming inability to enter latency, which rendered resistant isolates more susceptible to CTL-mediated immune clearance. Here, we investigated the ability of dCA-resistant viruses to replicate in vivo using a humanized mouse model of HIV infection. Animals were infected with WT or two dCA-resistant HIV-1 isolates in the absence of dCA and followed for 5 weeks. dCA-resistant viruses exhibited lower replication rates compared to WT. Viral replication was suppressed early after infection, with viral emergence at later time points. Multiplex analysis of cytokine and chemokines from plasma samples early after infection revealed no differences in expression levels between groups, suggesting that dCA-resistance viruses did not elicit potent innate immune responses capable of blocking the establishment of infection. Viral single genome sequencing results from plasma samples collected at euthanasia revealed that at least half of the total number of mutations in the LTR region of the HIV genome considered essential for dCA evasion reverted to WT. These results suggest that dCA-resistant viruses identified in vitro suffer a fitness cost in vivo, with mutations in LTR and Nef pressured to revert to wild type.
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Affiliation(s)
- Lijun Ling
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ana R. Leda
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL 33458, USA
| | - Nurjahan Begum
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rae Ann Spagnuolo
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Angela Wahl
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - J. Victor Garcia
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Susana T. Valente
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL 33458, USA
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Feng C, Jin C, Liu K, Yang Z. Microbiota-derived short chain fatty acids: Their role and mechanisms in viral infections. Biomed Pharmacother 2023. [DOI: 10.1016/j.biopha.2023.114414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
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9
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Horvath RM, Dahabieh M, Malcolm T, Sadowski I. TRIM24 controls induction of latent HIV-1 by stimulating transcriptional elongation. Commun Biol 2023; 6:86. [PMID: 36690785 PMCID: PMC9870992 DOI: 10.1038/s42003-023-04484-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 01/15/2023] [Indexed: 01/24/2023] Open
Abstract
Binding of USF1/2 and TFII-I (RBF-2) at conserved sites flanking the HIV-1 LTR enhancer is essential for reactivation from latency in T cells, with TFII-I knockdown rendering the provirus insensitive to T cell signaling. We identified an interaction of TFII-I with the tripartite motif protein TRIM24, and these factors were found to be constitutively associated with the HIV-1 LTR. Similar to the effect of TFII-I depletion, loss of TRIM24 impaired reactivation of HIV-1 in response to T cell signaling. TRIM24 deficiency did not affect recruitment of RNA Pol II to the LTR promoter, but inhibited transcriptional elongation, an effect that was associated with decreased RNA Pol II CTD S2 phosphorylation and impaired recruitment of CDK9. A considerable number of genomic loci are co-occupied by TRIM24/TFII-I, and we found that TRIM24 deletion caused altered T cell immune response, an effect that is facilitated by TFII-I. These results demonstrate a role of TRIM24 for regulation of transcriptional elongation from the HIV-1 promoter, through its interaction with TFII-I, and by recruitment of P-TEFb. Furthermore, these factors co-regulate a significant proportion of genes involved in T cell immune response, consistent with tight coupling of HIV-1 transcriptional activation and T cell signaling.
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Affiliation(s)
- Riley M Horvath
- Department of Biochemistry and Molecular Biology, Molecular Epigenetics Group, LSI, University of British Columbia, Vancouver, B.C., Canada
| | - Matthew Dahabieh
- Department of Biochemistry and Molecular Biology, Molecular Epigenetics Group, LSI, University of British Columbia, Vancouver, B.C., Canada
| | - Tom Malcolm
- Department of Biochemistry and Molecular Biology, Molecular Epigenetics Group, LSI, University of British Columbia, Vancouver, B.C., Canada
| | - Ivan Sadowski
- Department of Biochemistry and Molecular Biology, Molecular Epigenetics Group, LSI, University of British Columbia, Vancouver, B.C., Canada.
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Mediouni S, Lyu S, Schader SM, Valente ST. Forging a Functional Cure for HIV: Transcription Regulators and Inhibitors. Viruses 2022; 14:1980. [PMID: 36146786 PMCID: PMC9502519 DOI: 10.3390/v14091980] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/28/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Current antiretroviral therapy (ART) increases the survival of HIV-infected individuals, yet it is not curative. The major barrier to finding a definitive cure for HIV is our inability to identify and eliminate long-lived cells containing the dormant provirus, termed viral reservoir. When ART is interrupted, the viral reservoir ensures heterogenous and stochastic HIV viral gene expression, which can reseed infection back to pre-ART levels. While strategies to permanently eradicate the virus have not yet provided significant success, recent work has focused on the management of this residual viral reservoir to effectively limit comorbidities associated with the ongoing viral transcription still observed during suppressive ART, as well as limit the need for daily ART. Our group has been at the forefront of exploring the viability of the block-and-lock remission approach, focused on the long-lasting epigenetic block of viral transcription such that without daily ART, there is no risk of viral rebound, transmission, or progression to AIDS. Numerous studies have reported inhibitors of both viral and host factors required for HIV transcriptional activation. Here, we highlight and review some of the latest HIV transcriptional inhibitor discoveries that may be leveraged for the clinical exploration of block-and-lock and revolutionize the way we treat HIV infections.
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Affiliation(s)
- Sonia Mediouni
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
| | - Shuang Lyu
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
| | - Susan M. Schader
- Department of Infectious Disease Research, Drug Development Division, Southern Research, 431 Aviation Way, Frederick, MD 21701, USA
| | - Susana T. Valente
- Department of Immunology and Microbiology, UF Scripps Biomedical Research, 130 Scripps Way, 3C1, Jupiter, FL 33458, USA
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11
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Kuniholm J, Coote C, Henderson AJ. Defective HIV-1 genomes and their potential impact on HIV pathogenesis. Retrovirology 2022; 19:13. [PMID: 35764966 PMCID: PMC9238239 DOI: 10.1186/s12977-022-00601-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/17/2022] [Indexed: 11/28/2022] Open
Abstract
Defective HIV-1 proviruses represent a population of viral genomes that are selected for by immune pressures, and clonally expanded to dominate the persistent HIV-1 proviral genome landscape. There are examples of RNA and protein expression from these compromised genomes which are generated by a variety of mechanisms. Despite the evidence that these proviruses are transcribed and translated, their role in HIV pathogenesis has not been fully explored. The potential for these genomes to participate in immune stimulation is particularly relevant considering the accumulation of cells harboring these defective proviruses over the course of antiretroviral therapy in people living with HIV. The expression of defective proviruses in different cells and tissues could drive innate sensing mechanisms and inflammation. They may also alter antiviral T cell responses and myeloid cell functions that directly contribute to HIV-1 associated chronic comorbidities. Understanding the impact of these defective proviruses needs to be considered as we advance cure strategies that focus on targeting the diverse population of HIV-1 proviral genomes.
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Affiliation(s)
- Jeffrey Kuniholm
- Department of Microbiology, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, 02116, USA
| | - Carolyn Coote
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, 02116, USA
| | - Andrew J Henderson
- Department of Microbiology, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, 02116, USA. .,Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, 02116, USA.
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12
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Crespo R, Rao S, Mahmoudi T. HibeRNAtion: HIV-1 RNA Metabolism and Viral Latency. Front Cell Infect Microbiol 2022; 12:855092. [PMID: 35774399 PMCID: PMC9237370 DOI: 10.3389/fcimb.2022.855092] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/10/2022] [Indexed: 01/12/2023] Open
Abstract
HIV-1 infection remains non-curative due to the latent reservoir, primarily a small pool of resting memory CD4+ T cells bearing replication-competent provirus. Pharmacological reversal of HIV-1 latency followed by intrinsic or extrinsic cell killing has been proposed as a promising strategy to target and eliminate HIV-1 viral reservoirs. Latency reversing agents have been extensively studied for their role in reactivating HIV-1 transcription in vivo, although no permanent reduction of the viral reservoir has been observed thus far. This is partly due to the complex nature of latency, which involves strict intrinsic regulation at multiple levels at transcription and RNA processing. Still, the molecular mechanisms that control HIV-1 latency establishment and maintenance have been almost exclusively studied in the context of chromatin remodeling, transcription initiation and elongation and most known LRAs target LTR-driven transcription by manipulating these. RNA metabolism is a largely understudies but critical mechanistic step in HIV-1 gene expression and latency. In this review we provide an update on current knowledge on the role of RNA processing mechanisms in viral gene expression and latency and speculate on the possible manipulation of these pathways as a therapeutic target for future cure studies.
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Affiliation(s)
- Raquel Crespo
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Shringar Rao
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Pathology, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Urology, Erasmus University Medical Center, Rotterdam, Netherlands
- *Correspondence: Tokameh Mahmoudi,
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13
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HIV UTR, LTR, and Epigenetic Immunity. Viruses 2022; 14:v14051084. [PMID: 35632825 PMCID: PMC9146425 DOI: 10.3390/v14051084] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/05/2022] [Accepted: 05/13/2022] [Indexed: 02/06/2023] Open
Abstract
The duel between humans and viruses is unending. In this review, we examine the HIV RNA in the form of un-translated terminal region (UTR), the viral DNA in the form of long terminal repeat (LTR), and the immunity of human DNA in a format of epigenetic regulation. We explore the ways in which the human immune responses to invading pathogenic viral nucleic acids can inhibit HIV infection, exemplified by a chromatin vaccine (cVaccine) to elicit the immunity of our genome—epigenetic immunity towards a cure.
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14
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Abstract
Combinatory antiretroviral therapy (cART) reduces human immunodeficiency virus type 1 (HIV-1) replication but is not curative because cART interruption almost invariably leads to a rapid rebound of viremia due to the persistence of stable HIV-1-infected cellular reservoirs. These reservoirs are mainly composed of CD4+ T cells harboring replication-competent latent proviruses. A broadly explored approach to reduce the HIV-1 reservoir size, the shock and kill strategy, consists of reactivating HIV-1 gene expression from the latently infected cellular reservoirs (the shock), followed by killing of the virus-producing infected cells (the kill). Based on improved understanding of the multiple molecular mechanisms controlling HIV-1 latency, distinct classes of latency reversing agents (LRAs) have been studied for their efficiency to reactivate viral gene expression in in vitro and ex vivo cell models. Here, we provide an up-to-date review of these different mechanistic classes of LRAs and discuss optimizations of the shock strategy by combining several LRAs simultaneously or sequentially.
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Affiliation(s)
- Anthony Rodari
- Service of Molecular Virology, Department of Molecular Biology, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium;
| | - Gilles Darcis
- Infectious Diseases Department, Liège University Hospital, 4000 Liège, Belgium
| | - Carine M Van Lint
- Service of Molecular Virology, Department of Molecular Biology, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium;
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15
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Epigenetic Mechanisms of HIV-1 Persistence. Vaccines (Basel) 2021; 9:vaccines9050514. [PMID: 34067608 PMCID: PMC8156729 DOI: 10.3390/vaccines9050514] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/01/2021] [Accepted: 05/11/2021] [Indexed: 12/14/2022] Open
Abstract
Eradicating HIV-1 in infected individuals will not be possible without addressing the persistence of the virus in its multiple reservoirs. In this context, the molecular characterization of HIV-1 persistence is key for the development of rationalized therapeutic interventions. HIV-1 gene expression relies on the redundant and cooperative recruitment of cellular epigenetic machineries to cis-regulatory proviral regions. Furthermore, the complex repertoire of HIV-1 repression mechanisms varies depending on the nature of the viral reservoir, although, so far, few studies have addressed the specific regulatory mechanisms of HIV-1 persistence in other reservoirs than the well-studied latently infected CD4+ T cells. Here, we present an exhaustive and updated picture of the heterochromatinization of the HIV-1 promoter in its different reservoirs. We highlight the complexity, heterogeneity and dynamics of the epigenetic mechanisms of HIV-1 persistence, while discussing the importance of further understanding HIV-1 gene regulation for the rational design of novel HIV-1 cure strategies.
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16
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Janssens J, Bruggemans A, Christ F, Debyser Z. Towards a Functional Cure of HIV-1: Insight Into the Chromatin Landscape of the Provirus. Front Microbiol 2021; 12:636642. [PMID: 33868195 PMCID: PMC8044952 DOI: 10.3389/fmicb.2021.636642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/09/2021] [Indexed: 12/19/2022] Open
Abstract
Despite potent combination antiretroviral therapy, HIV-1 infection persists due to irreversible integration of the virus in long-living cells of the immune system. The main focus of HIV-1 cure strategies has been on HIV-1 eradication, yet without great success so far. Therefore, HIV-1 remission or a functional cure, whereby the virus is silenced rather than eradicated, is considered as an alternative strategy. Elite controllers, individuals who spontaneously control HIV-1, may point us the way toward a functional HIV-1 cure. In order to achieve such a cure, a profound understanding of the mechanisms controlling HIV-1 expression and silencing is needed. In recent years, evidence has grown that the site of integration as well as the chromatin landscape surrounding the integration site affects the transcriptional state of the provirus. Still, at present, the impact of integration site selection on the establishment and maintenance of the HIV-1 reservoirs remains poorly understood. The discovery of LEDGF/p75 as a binding partner of HIV-1 integrase has led to a better understanding of integration site selection. LEDGF/p75 is one of the important determinants of integration site selection and targets integration toward active genes. In this review, we will provide an overview of the most important determinants of integration site selection. Secondly, we will discuss the chromatin landscape at the integration site and its implications on HIV-1 gene expression and silencing. Finally, we will discuss how interventions that affect integration site selection or modifications of the chromatin could yield a functional cure of HIV-1 infection.
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Affiliation(s)
- Julie Janssens
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Anne Bruggemans
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Frauke Christ
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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17
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In Vitro Pharmacokinetic/Pharmacodynamic Modeling of HIV Latency Reversal by Novel HDAC Inhibitors Using an Automated Platform. SLAS DISCOVERY 2021; 26:642-654. [DOI: 10.1177/2472555220983810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Antiretroviral therapy is able to effectively control but not eradicate HIV infection, which can persist, leading to the need for lifelong therapy. The existence of latently HIV-infected cells is a major barrier to the eradication of chronic HIV infection. Histone deacetylase inhibitors (HDACis), small molecules licensed for oncology indications, have shown the ability to produce HIV transcripts in vitro and in vivo. The pharmacologic parameters that drive optimal HIV latency reversal in vivo are unknown and could be influenced by such factors as the HDACi binding kinetics, concentration of compound, and duration of exposure. This study evaluates how these parameters affect HIV latency reversal for a series of novel HDACis that differ in their enzymatic on and off rates. Varying cellular exposure, using automated washout methods of HDACi in a Jurkat cell model of HIV latency, led to the investigation of the relationship between pharmacokinetic (PK) properties, target engagement (TE), and pharmacodynamic (PD) responses. Using an automated robotic platform enabled miniaturization of a suspension cell-based washout assay that required multiple manipulations over the 48 h duration of the assay. Quantification of histone acetylation (TE) revealed that HDACis showed early peaks and differences in the durability of response between different investigated HDACis. By expanding the sample times, the shift between TE and PD, as measured by green fluorescent protein, could be fully characterized. The comprehensive data set generated by automating the assays described here was used to establish a PK/PD model for HDACi-induced HIV latency reversal.
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18
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Moranguinho I, Valente ST. Block-And-Lock: New Horizons for a Cure for HIV-1. Viruses 2020; 12:v12121443. [PMID: 33334019 PMCID: PMC7765451 DOI: 10.3390/v12121443] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022] Open
Abstract
HIV-1/AIDS remains a global public health problem. The world health organization (WHO) reported at the end of 2019 that 38 million people were living with HIV-1 worldwide, of which only 67% were accessing antiretroviral therapy (ART). Despite great success in the clinical management of HIV-1 infection, ART does not eliminate the virus from the host genome. Instead, HIV-1 remains latent as a viral reservoir in any tissue containing resting memory CD4+ T cells. The elimination of these residual proviruses that can reseed full-blown infection upon treatment interruption remains the major barrier towards curing HIV-1. Novel approaches have recently been developed to excise or disrupt the virus from the host cells (e.g., gene editing with the CRISPR-Cas system) to permanently shut off transcription of the virus (block-and-lock and RNA interference strategies), or to reactivate the virus from cell reservoirs so that it can be eliminated by the immune system or cytopathic effects (shock-and-kill strategy). Here, we will review each of these approaches, with the major focus placed on the block-and-lock strategy.
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19
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Depicting HIV-1 Transcriptional Mechanisms: A Summary of What We Know. Viruses 2020; 12:v12121385. [PMID: 33287435 PMCID: PMC7761857 DOI: 10.3390/v12121385] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 12/19/2022] Open
Abstract
Despite the introduction of combinatory antiretroviral therapy (cART), HIV-1 infection cannot be cured and is still one of the major health issues worldwide. Indeed, as soon as cART is interrupted, a rapid rebound of viremia is observed. The establishment of viral latency and the persistence of the virus in cellular reservoirs constitute the main barrier to HIV eradication. For this reason, new therapeutic approaches have emerged to purge or restrain the HIV-1 reservoirs in order to cure infected patients. However, the viral latency is a multifactorial process that depends on various cellular mechanisms. Since these new therapies mainly target viral transcription, their development requires a detailed and precise understanding of the regulatory mechanism underlying HIV-1 transcription. In this review, we discuss the complex molecular transcriptional network regulating HIV-1 gene expression by focusing on the involvement of host cell factors that could be used as potential drug targets to design new therapeutic strategies and, to a larger extent, to reach an HIV-1 functional cure.
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20
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Opioid-Mediated HIV-1 Immunopathogenesis. J Neuroimmune Pharmacol 2020; 15:628-642. [PMID: 33029670 DOI: 10.1007/s11481-020-09960-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023]
Abstract
Despite the ability of combination antiretroviral therapy to dramatically suppress viremia, the brain continues to be a reservoir of HIV-1 low-level replication. Adding further complexity to this is the comorbidity of drug abuse with HIV-1 associated neurocognitive disorders and neuroHIV. Among several abused drugs, the use of opiates is highly prevalent in HIV-1 infected individuals, both as an abused drug as well as for pain management. Opioids and their receptors have attained notable attention owing to their ability to modulate immune functions, in turn, impacting disease progression. Various cell culture, animal and human studies have implicated the role of opioids and their receptors in modulating viral replication and virus-mediated pathology both positively and negatively. Further, the combinatorial effects of HIV-1/HIV-1 proteins and morphine have demonstrated activation of inflammatory signaling in the host system. Herein, we summarized the current knowledge on the role of opioids on peripheral immunopathogenesis, viral immunopathogenesis, epigenetic profiles of the host and viral genome, neuropathogenesis of SIV/SHIV-infected non-human primates, blood-brain-barrier, HIV-1 viral latency, and viral rebound. Overall, this review provides recent insights into the role of opioids in HIV-1 immunopathogenesis. Graphical abstract.
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21
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Zicari S, Sharma AL, Sahu G, Dubrovsky L, Sun L, Yue H, Jada T, Ochem A, Simon G, Bukrinsky M, Tyagi M. DNA dependent protein kinase (DNA-PK) enhances HIV transcription by promoting RNA polymerase II activity and recruitment of transcription machinery at HIV LTR. Oncotarget 2020; 11:699-726. [PMID: 32133046 PMCID: PMC7041937 DOI: 10.18632/oncotarget.27487] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/29/2020] [Indexed: 01/24/2023] Open
Abstract
Despite reductions in mortality from the use of highly active antiretroviral therapy (HAART), the presence of latent or transcriptionally silent proviruses prevents HIV cure/eradication. We have previously reported that DNA-dependent protein kinase (DNA-PK) facilitates HIV transcription by interacting with the RNA polymerase II (RNAP II) complex recruited at HIV LTR. In this study, using different cell lines and peripheral blood mononuclear cells (PBMCs) of HIV-infected patients, we found that DNA-PK stimulates HIV transcription at several stages, including initiation, pause-release and elongation. We are reporting for the first time that DNA-PK increases phosphorylation of RNAP II C-terminal domain (CTD) at serine 5 (Ser5) and serine 2 (Ser2) by directly catalyzing phosphorylation and by augmenting the recruitment of the positive transcription elongation factor (P-TEFb) at HIV LTR. Our findings suggest that DNA-PK expedites the establishment of euchromatin structure at HIV LTR. DNA-PK inhibition/knockdown leads to the severe impairment of HIV replication and reactivation of latent HIV provirus. DNA-PK promotes the recruitment of Tripartite motif-containing 28 (TRIM28) at LTR and assists the release of paused RNAP II through TRIM28 phosphorylation. These results provide the mechanisms through which DNA-PK controls the HIV gene expression and, likely, can be extended to cellular gene expression, including during cell malignancy, where the role of DNA-PK has been well-established.
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Affiliation(s)
- Sonia Zicari
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.,Section of Intercellular Interactions, Eunice-Kennedy National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Department of Pediatric Medicine, The Bambino Gesù Children's Hospital, Rome, Italy.,These authors contributed equally to this work
| | - Adhikarimayum Lakhikumar Sharma
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.,These authors contributed equally to this work
| | - Geetaram Sahu
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA.,These authors contributed equally to this work
| | - Larisa Dubrovsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037, USA
| | - Lin Sun
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA
| | - Han Yue
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA
| | - Tejaswi Jada
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA
| | - Alex Ochem
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Wernher and Beit Building (South), Observatory 7925, Cape Town, South Africa
| | - Gary Simon
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037, USA
| | - Mudit Tyagi
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.,Division of Infectious Diseases, Department of Medicine, George Washington University, Washington DC 20037, USA.,Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037, USA
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22
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Abstract
Human immunodeficiency virus 1 (HIV-1) replicates through the integration of its viral DNA into the genome of human immune target cells. Chronically infected individuals thus carry a genomic burden of virus-derived sequences that persists through antiretroviral therapy. This burden consists of a small fraction of intact, but transcriptionally silenced, i.e. latent, viral genomes and a dominant fraction of defective sequences. Remarkably, all viral-derived sequences are subject to interaction with host cellular physiology at various levels. In this review, we focus on epigenetic aspects of this interaction. We provide a comprehensive overview of how epigenetic mechanisms contribute to establishment and maintenance of HIV-1 gene repression during latency. We furthermore summarize findings indicating that HIV-1 infection leads to changes in the epigenome of target and bystander immune cells. Finally, we discuss how an improved understanding of epigenetic features and mechanisms involved in HIV-1 infection could be exploited for clinical use.
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23
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Vansant G, Bruggemans A, Janssens J, Debyser Z. Block-And-Lock Strategies to Cure HIV Infection. Viruses 2020; 12:E84. [PMID: 31936859 PMCID: PMC7019976 DOI: 10.3390/v12010084] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 12/12/2022] Open
Abstract
Today HIV infection cannot be cured due to the presence of a reservoir of latently infected cells inducing a viral rebound upon treatment interruption. Hence, the latent reservoir is considered as the major barrier for an HIV cure. So far, efforts to completely eradicate the reservoir via a shock-and-kill approach have proven difficult and unsuccessful. Therefore, more research has been done recently on an alternative block-and-lock functional cure strategy. In contrast to the shock-and-kill strategy that aims to eradicate the entire reservoir, block-and-lock aims to permanently silence all proviruses, even after treatment interruption. HIV silencing can be achieved by targeting different factors of the transcription machinery. In this review, we first describe the underlying mechanisms of HIV transcription and silencing. Next, we give an overview of the different block-and-lock strategies under investigation.
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Affiliation(s)
- Gerlinde Vansant
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit, Leuven, 3000 Flanders, Belgium
| | - Anne Bruggemans
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit, Leuven, 3000 Flanders, Belgium
| | - Julie Janssens
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit, Leuven, 3000 Flanders, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit, Leuven, 3000 Flanders, Belgium
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24
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Chung CH, Allen AG, Sullivan NT, Atkins A, Nonnemacher MR, Wigdahl B, Dampier W. Computational Analysis Concerning the Impact of DNA Accessibility on CRISPR-Cas9 Cleavage Efficiency. Mol Ther 2020; 28:19-28. [PMID: 31672284 PMCID: PMC6953893 DOI: 10.1016/j.ymthe.2019.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 09/26/2019] [Accepted: 10/10/2019] [Indexed: 12/15/2022] Open
Abstract
Defining the variables that impact the specificity of CRISPR/Cas9 has been a major research focus. Whereas sequence complementarity between guide RNA and target DNA substantially dictates cleavage efficiency, DNA accessibility of the targeted loci has also been hypothesized to be an important factor. In this study, functional data from two genome-wide assays, genome-wide, unbiased identification of DSBs enabled by sequencing (GUIDE-seq) and circularization for in vitro reporting of cleavage effects by sequencing (CIRCLE-seq), have been computationally analyzed in conjunction with DNA accessibility determined via DNase I-hypersensitive sequencing from the Encyclopedia of DNA Elements (ENCODE) Database and transcriptome from the Sequence Read Archive to determine whether cellular factors influence CRISPR-induced cleavage efficiency. CIRCLE-seq and GUIDE-seq datasets were selected to represent the absence and presence of cellular factors, respectively. Data analysis revealed that correlations between sequence similarity and CRISPR-induced cleavage frequency were altered by the presence of cellular factors that modulated the level of DNA accessibility. The above-mentioned correlation was abolished when cleavage sites were located in less accessible regions. Furthermore, CRISPR-mediated edits were permissive even at regions that were insufficient for most endogenous genes to be expressed. These results provide a strong basis to dissect the contribution of local chromatin modulation markers on CRISPR-induced cleavage efficiency.
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Affiliation(s)
- Cheng-Han Chung
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Alexander G Allen
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Neil T Sullivan
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Andrew Atkins
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - Will Dampier
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA; Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA; School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104, USA.
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25
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Resistance to the Tat Inhibitor Didehydro-Cortistatin A Is Mediated by Heightened Basal HIV-1 Transcription. mBio 2019; 10:mBio.01750-18. [PMID: 31266880 PMCID: PMC6606815 DOI: 10.1128/mbio.01750-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat binds the viral RNA structure transactivation-responsive element (TAR) and recruits transcriptional cofactors, amplifying viral mRNA expression. The Tat inhibitor didehydro-cortistatin A (dCA) promotes a state of persistent latency, refractory to viral reactivation. Here we investigated mechanisms of HIV-1 resistance to dCA in vitro Mutations in Tat and TAR were not identified, consistent with the high level of conservation of these elements. Instead, viruses resistant to dCA developed higher Tat-independent basal transcription. We identified a combination of mutations in the HIV-1 promoter that increased basal transcriptional activity and modifications in viral Nef and Vpr proteins that increased NF-κB activity. Importantly, these variants are unlikely to enter latency due to accrued transcriptional fitness and loss of sensitivity to Tat feedback loop regulation. Furthermore, cells infected with these variants become more susceptible to cytopathic effects and immune-mediated clearance. This is the first report of viral escape to a Tat inhibitor resulting in heightened Tat-independent activity, all while maintaining wild-type Tat and TAR.IMPORTANCE HIV-1 Tat enhances viral RNA transcription by binding to TAR and recruiting activating factors. Tat enhances its own transcription via a positive-feedback loop. Didehydro-cortistatin A (dCA) is a potent Tat inhibitor, reducing HIV-1 transcription and preventing viral rebound. dCA activity demonstrates the potential of the "block-and-lock" functional cure approaches. We investigated the viral genetic barrier to dCA resistance in vitro While mutations in Tat and TAR were not identified, mutations in the promoter and in the Nef and Vpr proteins promoted high Tat-independent activity. Promoter mutations increased the basal transcription, while Nef and Vpr mutations increased NF-κB nuclear translocation. This heightened transcriptional activity renders CD4+ T cells infected with these viruses more susceptible to cytotoxic T cell-mediated killing and to cell death by cytopathic effects. Results provide insights on drug resistance to a novel class of antiretrovirals and reveal novel aspects of viral transcriptional regulation.
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26
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Li C, Mousseau G, Valente ST. Tat inhibition by didehydro-Cortistatin A promotes heterochromatin formation at the HIV-1 long terminal repeat. Epigenetics Chromatin 2019; 12:23. [PMID: 30992052 PMCID: PMC6466689 DOI: 10.1186/s13072-019-0267-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/30/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Transcription from the integrated HIV-1 promoter is directly governed by its chromatin environment, and the nucleosome-1 downstream from the transcription start site directly impedes transcription from the HIV-1 promoter. The HIV-1 Tat protein regulates the passage from viral latency to active transcription by binding to the viral mRNA hairpin (TAR) and recruiting transcriptional factors to promote transcriptional elongation. The Tat inhibitor didehydro-Cortistatin A (dCA) inhibits transcription and overtime, the lack of low-grade transcriptional events, triggers epigenetic changes at the latent loci that "lock" HIV transcription in a latent state. RESULTS Here we investigated those epigenetic changes using multiple cell line models of HIV-1 latency and active transcription. We demonstrated that dCA treatment does not alter the classic nucleosome positioning at the HIV-1 promoter, but promotes tighter nucleosome/DNA association correlating with increased deacetylated H3 occupancy at nucleosome-1. Recruitment of the SWI/SNF chromatin remodeling complex PBAF, necessary for Tat-mediated transactivation, is also inhibited, while recruitment of the repressive BAF complex is enhanced. These results were supported by loss of RNA polymerase II recruitment on the HIV genome, even during strong stimulation with latency-reversing agents. No epigenetic changes were detected in cell line models of latency with Tat-TAR incompetent proviruses confirming the specificity of dCA for Tat. CONCLUSIONS We characterized the dCA-mediated epigenetic signature on the HIV genome, which translates into potent blocking effects on HIV expression, further strengthening the potential of Tat inhibitors in "block-and-lock" functional cure approaches.
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Affiliation(s)
- Chuan Li
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Guillaume Mousseau
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Susana T Valente
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
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27
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Marian CA, Stoszko M, Wang L, Leighty MW, de Crignis E, Maschinot CA, Gatchalian J, Carter BC, Chowdhury B, Hargreaves DC, Duvall JR, Crabtree GR, Mahmoudi T, Dykhuizen EC. Small Molecule Targeting of Specific BAF (mSWI/SNF) Complexes for HIV Latency Reversal. Cell Chem Biol 2018; 25:1443-1455.e14. [PMID: 30197195 PMCID: PMC6404985 DOI: 10.1016/j.chembiol.2018.08.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 05/24/2018] [Accepted: 08/06/2018] [Indexed: 12/19/2022]
Abstract
The persistence of a pool of latently HIV-1-infected cells despite combination anti-retroviral therapy treatment is the major roadblock for a cure. The BAF (mammalian SWI/SNF) chromatin remodeling complex is involved in establishing and maintaining viral latency, making it an attractive drug target for HIV-1 latency reversal. Here we report a high-throughput screen for inhibitors of BAF-mediated transcription in cells and the subsequent identification of a 12-membered macrolactam. This compound binds ARID1A-specific BAF complexes, prevents nucleosomal positioning, and relieves transcriptional repression of HIV-1. Through this mechanism, these compounds are able to reverse HIV-1 latency in an in vitro T cell line, an ex vivo primary cell model of HIV-1 latency, and in patient CD4+ T cells without toxicity or T cell activation. These macrolactams represent a class of latency reversal agents with unique mechanism of action, and can be combined with other latency reversal agents to improve reservoir targeting.
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Affiliation(s)
- Christine A Marian
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA
| | - Mateusz Stoszko
- Department of Biochemistry, Erasmus University Medical Center, Ee634, P.O. Box 2040, 3000CA Rotterdam, the Netherlands
| | - Lili Wang
- The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, MA 02142, USA
| | - Matthew W Leighty
- The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, MA 02142, USA
| | - Elisa de Crignis
- Department of Biochemistry, Erasmus University Medical Center, Ee634, P.O. Box 2040, 3000CA Rotterdam, the Netherlands
| | - Chad A Maschinot
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA
| | - Jovylyn Gatchalian
- Department of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N Torrey Pines Road, La Jolla, CA 92037, USA
| | - Benjamin C Carter
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA
| | - Basudev Chowdhury
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA
| | - Diana C Hargreaves
- Department of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jeremy R Duvall
- The Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, MA 02142, USA
| | - Gerald R Crabtree
- HHMI and the Departments of Developmental Biology and Pathology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA.
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, Ee634, P.O. Box 2040, 3000CA Rotterdam, the Netherlands.
| | - Emily C Dykhuizen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA.
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Roebuck KA, Saifuddin M. Regulation of HIV-1 transcription. Gene Expr 2018; 8:67-84. [PMID: 10551796 PMCID: PMC6157391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Human immunodeficiency virus type-1 (HIV-1) is a highly pathogenic lentivirus that requires transcription of its provirus genome for completion of the viral life cycle and the production of progeny virions. Since the first genetic analysis of HIV-1 in 1985, much has been learned about the transcriptional regulation of the HIV-1 genome in infected cells. It has been demonstrated that HIV-1 transcription depends on a varied and complex interaction of host cell transcription factors with the viral long terminal repeat (LTR) promoter. The regulatory elements within the LTR interact with constitutive and inducible transcription factors to direct the assembly of a stable transcription complex that stimulates multiple rounds of transcription by RNA polymerase II (RNAPII). However, the majority of these transcripts terminate prematurely in the absence of the virally encoded trans-activator protein Tat, which stimulates HIV-1 transcription elongation by interacting with a stem-loop RNA element (TAR) formed at the extreme 5' end of all viral transcripts. The Tat-TAR interaction recruits a cellular kinase into the initiation-elongation complex that alters the elongation properties of RNAPII during its transit through TAR. This review summarizes our current knowledge and understanding of the regulation of HIV-1 transcription in infected cells and highlights the important contributions human lentivirus gene regulation has made to our general understanding of the transcription process.
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Affiliation(s)
- K A Roebuck
- Department of Immunology/Microbiology, Rush Presbyterian St. Luke's Medical Center, Chicago, IL 60612, USA.
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29
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Castro-Gonzalez S, Colomer-Lluch M, Serra-Moreno R. Barriers for HIV Cure: The Latent Reservoir. AIDS Res Hum Retroviruses 2018; 34:739-759. [PMID: 30056745 PMCID: PMC6152859 DOI: 10.1089/aid.2018.0118] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Thirty-five years after the identification of HIV-1 as the causative agent of AIDS, we are still in search of vaccines and treatments to eradicate this devastating infectious disease. Progress has been made in understanding the molecular pathogenesis of this infection, which has been crucial for the development of the current therapy regimens. However, despite their efficacy at limiting active viral replication, these drugs are unable to purge the latent reservoir: a pool of cells that harbor transcriptionally inactive, but replication-competent HIV-1 proviruses, and that represent the main barrier to eradicate HIV-1 from affected individuals. In this review, we discuss advances in the field that have allowed a better understanding of HIV-1 latency, including the diverse cell types that constitute the latent reservoir, factors influencing latency, tools to study HIV-1 latency, as well as current and prospective therapeutic approaches to target these latently infected cells, so a functional cure for HIV/AIDS can become a reality.
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Affiliation(s)
- Sergio Castro-Gonzalez
- Department of Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, Texas
| | - Marta Colomer-Lluch
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Ruth Serra-Moreno
- Department of Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, Texas
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30
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Sen S, Maulik U. Recent advancement toward significant association between disordered transcripts and virus-infected diseases: a survey. Brief Funct Genomics 2018; 17:458-470. [DOI: 10.1093/bfgp/ely021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sagnik Sen
- Department of Computer Science and Engineering, Jadavpur University, Kolkata-700032, India
| | - Ujjwal Maulik
- Department of Computer Science and Engineering, Jadavpur University, Kolkata-700032, India
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31
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Khan S, Iqbal M, Tariq M, Baig SM, Abbas W. Epigenetic regulation of HIV-1 latency: focus on polycomb group (PcG) proteins. Clin Epigenetics 2018; 10:14. [PMID: 29441145 PMCID: PMC5800276 DOI: 10.1186/s13148-018-0441-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/05/2018] [Indexed: 01/10/2023] Open
Abstract
HIV-1 latency allows the virus to persist until reactivation, in a transcriptionally silent form in its cellular reservoirs despite the presence of effective cART. Such viral persistence represents a major barrier to HIV eradication since treatment interruption leads to rebound plasma viremia. Polycomb group (PcG) proteins have recently got a considerable attention in regulating HIV-1 post-integration latency as they are involved in the repression of proviral gene expression through the methylation of histones. This epigenetic regulation plays an important role in the establishment and maintenance of HIV-1 latency. In fact, PcG proteins act in complexes and modulate the epigenetic signatures of integrated HIV-1 promoter. Key role played by PcG proteins in the molecular control of HIV-1 latency has led to hypothesize that PcG proteins may represent a valuable target for future HIV-1 therapy in purging HIV-1 reservoirs. In this regard, various small molecules have been synthesized or explored to specifically block the epigenetic activity of PcG. In this review, we will highlight the possible therapeutic approaches to achieve either a functional or sterilizing cure of HIV-1 infection with special focus on histone methylation by PcG proteins together with current and novel pharmacological approaches to reactivate HIV-1 from latency that could ultimately lead towards a better clearance of viral latent reservoirs.
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Affiliation(s)
- Sheraz Khan
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Mazhar Iqbal
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Muhammad Tariq
- Department of Biology (Epigenetics group), SBA School of Science and Engineering, LUMS, Lahore, 54792 Pakistan
| | - Shahid M. Baig
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Wasim Abbas
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
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Ne E, Palstra RJ, Mahmoudi T. Transcription: Insights From the HIV-1 Promoter. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 335:191-243. [DOI: 10.1016/bs.ircmb.2017.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Conrad RJ, Fozouni P, Thomas S, Sy H, Zhang Q, Zhou MM, Ott M. The Short Isoform of BRD4 Promotes HIV-1 Latency by Engaging Repressive SWI/SNF Chromatin-Remodeling Complexes. Mol Cell 2017; 67:1001-1012.e6. [PMID: 28844864 DOI: 10.1016/j.molcel.2017.07.025] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/24/2017] [Accepted: 07/25/2017] [Indexed: 11/18/2022]
Abstract
BET proteins commonly activate cellular gene expression, yet inhibiting their recruitment paradoxically reactivates latent HIV-1 transcription. Here we identify the short isoform of BET family member BRD4 (BRD4S) as a corepressor of HIV-1 transcription. We found that BRD4S was enriched in chromatin fractions of latently infected T cells, and it was more rapidly displaced from chromatin upon BET inhibition than the long isoform. BET inhibition induced marked nucleosome remodeling at the latent HIV-1 promoter, which was dependent on the activity of BRG1-associated factors (BAF), an SWI/SNF chromatin-remodeling complex with known repressive functions in HIV-1 transcription. BRD4S directly bound BRG1, a catalytic subunit of BAF, via its bromodomain and extraterminal (ET) domain, and this isoform was necessary for BRG1 recruitment to latent HIV-1 chromatin. Using chromatin immunoprecipitation sequencing (ChIP-seq) combined with assay for transposase-accessible chromatin coupled to high-throughput sequencing (ATAC-seq) data, we found that the latent HIV-1 promoter phenotypically resembles endogenous long terminal repeat (LTR) sequences, pointing to a select role of BRD4S-BRG1 complexes in genomic silencing of invasive retroelements.
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Affiliation(s)
- Ryan J Conrad
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA; Graduate Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Parinaz Fozouni
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Sean Thomas
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hendrik Sy
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Qiang Zhang
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ming-Ming Zhou
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Melanie Ott
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA; Graduate Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA.
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34
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Unravelling HIV-1 Latency, One Cell at a Time. Trends Microbiol 2017; 25:932-941. [PMID: 28668335 DOI: 10.1016/j.tim.2017.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/22/2017] [Accepted: 06/01/2017] [Indexed: 12/14/2022]
Abstract
A single virus is capable of infecting and replicating in a single cell. Recent advances across single-cell omics technologies - genomics, epigenomics, transcriptomics, epitranscriptomics, proteomics, and metabolomics - will offer unprecedented opportunities to gain more insights into the various aspects of the life cycle of viruses and their impact on the host cell. Here, using the human immunodeficiency virus type 1 (HIV-1) as an example, we summarize the current knowledge and the future potential of single-cell omics in the investigation of an important aspect of the life cycle of HIV-1 that represents a major hurdle in achieving viral eradication, HIV-1 latency.
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35
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Turner AMW, Margolis DM. Chromatin Regulation and the Histone Code in HIV Latency
. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2017; 90:229-243. [PMID: 28656010 PMCID: PMC5482300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The formation of a latent reservoir of Human Immunodeficiency Virus (HIV) infection hidden from immune clearance remains a significant obstacle to approaches to eradicate HIV infection. Towards an understanding of the mechanisms of HIV persistence, there is a growing body of work implicating epigenetic regulation of chromatin in establishment and maintenance of this latent reservoir. Here we discuss recent advances in the field of chromatin regulation, specifically in our understanding of the histone code, and how these discoveries relate to our current knowledge of the chromatin mechanisms linked to HIV transcriptional repression and the reversal of latency. We also examine mechanisms unexplored in the context of HIV latency and briefly discuss current therapies aimed at the induction of proviral expression within latently infected cells. We aim to emphasize that a greater understanding of the epigenetic mechanisms which govern HIV latency could lead to new therapeutic targets for latency reversal and clearance cure strategies.
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Affiliation(s)
- Anne-Marie W. Turner
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC,Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - David M. Margolis
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC,Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC,Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC,To whom all correspondence should be addressed: David Margolis, University of North Carolina at Chapel Hill, 2016 Genetic Medicine Building, CB#7042, 120 Mason Farm Road, Chapel Hill, NC, 27599-7435, Tel: (919) 966-6388, .
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The Multifaceted Contributions of Chromatin to HIV-1 Integration, Transcription, and Latency. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 328:197-252. [PMID: 28069134 DOI: 10.1016/bs.ircmb.2016.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The capacity of the human immunodeficiency virus (HIV-1) to establish latent infections constitutes a major barrier to the development of a cure for HIV-1. In latent infection, replication competent HIV-1 provirus is integrated within the host genome but remains silent, masking the infected cells from the activity of the host immune response. Despite the progress in elucidating the molecular players that regulate HIV-1 gene expression, the mechanisms driving the establishment and maintenance of latency are still not fully understood. Transcription from the HIV-1 genome occurs in the context of chromatin and is subjected to the same regulatory mechanisms that drive cellular gene expression. Much like in eukaryotic genes, the nucleosomal landscape of the HIV-1 promoter and its position within genomic chromatin are determinants of its transcriptional activity. Understanding the multilayered chromatin-mediated mechanisms that underpin HIV-1 integration and expression is of utmost importance for the development of therapeutic strategies aimed at reducing the pool of latently infected cells. In this review, we discuss the impact of chromatin structure on viral integration, transcriptional regulation and latency, and the host factors that influence HIV-1 replication by regulating chromatin organization. Finally, we describe therapeutic strategies under development to target the chromatin-HIV-1 interplay.
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37
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Polizzotto MN, Chen G, Tressler RL, Godfrey C. Leveraging Cancer Therapeutics for the HIV Cure Agenda: Current Status and Future Directions. Drugs 2016. [PMID: 26224205 DOI: 10.1007/s40265-015-0426-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Despite effective antiretroviral therapy (ART) and undetectable HIV RNA in the plasma, latent replication-competent HIV persists indefinitely in long-lived cells. Cessation of ART results in rebound of HIV from these persistent reservoirs. While this was thought to be an insurmountable obstacle to viral eradication, recent cases suggest otherwise. To date one patient has been "cured" of HIV and several others have been able to interrupt ART without viral rebound for prolonged periods. These events have sparked renewed interest in developing strategies that will allow eradication of HIV in infected individuals. We review the current knowledge of HIV latency and the viral reservoir, describe the potential utility of emerging cancer therapeutics in HIV cure research with an emphasis on pathways implicated in reservoir persistence, and outline opportunities and challenges in the context of the current clinical trial and regulatory environment.
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Affiliation(s)
- Mark N Polizzotto
- HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, 5601 Fishers Lane, Bethesda, MD, 20892, USA,
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Short Intracellular HIV-1 Transcripts as Biomarkers of Residual Immune Activation in Patients on Antiretroviral Therapy. J Virol 2016; 90:5665-5676. [PMID: 27030274 DOI: 10.1128/jvi.03158-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 03/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED HIV-1 patients continue to remain at an abnormal immune status despite prolonged combination antiretroviral therapy (cART), which results in an increased risk of non-AIDS-related diseases. Given the growing recognition of the importance of understanding and controlling the residual virus in patients, additional virological markers to monitor infected cells are required. However, viral replication in circulating cells is much poorer than that in lymph nodes, which results in the absence of markers to distinguish these cells from uninfected cells in the blood. In this study, we identified prematurely terminated short HIV-1 transcripts (STs) in peripheral blood mononuclear cells (PBMCs) as an efficient intracellular biomarker to monitor viral activation and immune status in patients with cART-mediated full viral suppression in plasma. STs were detected in PBMCs obtained from both treated and untreated patients. ST levels in untreated patients generally increased with disease progression and decreased after treatment initiation. However, some patients exhibited sustained high levels of ST and low CD4(+) cell counts despite full viral suppression by treatment. The levels of STs strongly reflected chronic immune activation defined by coexpression of HLA-DR and CD38 on CD8(+) T cells, rather than circulating proviral load. These observations represent evidence for a relationship between viral persistence and host immune activation, which in turn results in the suboptimal increase in CD4(+) cells despite suppressive antiretroviral therapy. This cell-based measurement of viral persistence contributes to an improved understanding of the dynamics of viral persistence in cART patients and will guide therapeutic approaches targeting viral reservoirs. IMPORTANCE Combination antiretroviral therapy (cART) suppresses HIV-1 load to below the detectable limit in plasma. However, the virus persists, and patients remain at an abnormal immune status, which results in an increased risk of non-AIDS-related complications. To achieve a functional cure for HIV-1 infection, activities of viral reservoirs must be quantified and monitored. However, latently infected cells are difficult to be monitored. Here, we identified prematurely terminated short HIV-1 transcripts (STs) as an efficient biomarker for monitoring viral activation and immune status in patients with cART-mediated full viral suppression in plasma. This cell-based measurement of viral persistence will contribute to our understanding of the impact of residual virus on chronic immune activation in HIV-1 patients during cART.
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Conrad RJ, Ott M. Therapeutics Targeting Protein Acetylation Perturb Latency of Human Viruses. ACS Chem Biol 2016; 11:669-80. [PMID: 26845514 DOI: 10.1021/acschembio.5b00999] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Persistent viral infections are widespread and represent significant public health burdens. Some viruses endure in a latent state by co-opting the host epigenetic machinery to manipulate viral gene expression. Small molecules targeting epigenetic pathways are now in the clinic for certain cancers and are considered as potential treatment strategies to reverse latency in HIV-infected individuals. In this review, we discuss how drugs interfering with one epigenetic pathway, protein acetylation, perturb latency of three families of pathogenic human viruses-retroviruses, herpesviruses, and papillomaviruses.
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Affiliation(s)
- Ryan J. Conrad
- Gladstone Institute of Virology and Immunology, San Francisco, California 94158, United States
- Graduate
Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, California 94158, United States
- Department
of Medicine, University of California, San Francisco, California 94158, United States
| | - Melanie Ott
- Gladstone Institute of Virology and Immunology, San Francisco, California 94158, United States
- Graduate
Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, California 94158, United States
- Department
of Medicine, University of California, San Francisco, California 94158, United States
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40
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Chekuri A, Bhaskar C, Bollimpelli VS, Kondapi AK. TopoisomeraseIIβ in HIV-1 transactivation. Arch Biochem Biophys 2016; 593:90-7. [DOI: 10.1016/j.abb.2016.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/15/2022]
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Small Molecule Inhibitors of BAF; A Promising Family of Compounds in HIV-1 Latency Reversal. EBioMedicine 2015; 3:108-121. [PMID: 26870822 PMCID: PMC4739437 DOI: 10.1016/j.ebiom.2015.11.047] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/19/2015] [Accepted: 11/25/2015] [Indexed: 11/23/2022] Open
Abstract
Persistence of latently infected cells in presence of Anti-Retroviral Therapy presents the main obstacle to HIV-1 eradication. Much effort is thus placed on identification of compounds capable of HIV-1 latency reversal in order to render infected cells susceptible to viral cytopathic effects and immune clearance. We identified the BAF chromatin remodeling complex as a key player required for maintenance of HIV-1 latency, highlighting its potential as a molecular target for inhibition in latency reversal. Here, we screened a recently identified panel of small molecule inhibitors of BAF (BAFi's) for potential to activate latent HIV-1. Latency reversal was strongly induced by BAFi's Caffeic Acid Phenethyl Ester and Pyrimethamine, two molecules previously characterized for clinical application. BAFi's reversed HIV-1 latency in cell line based latency models, in two ex vivo infected primary cell models of latency, as well as in HIV-1 infected patient's CD4 + T cells, without inducing T cell proliferation or activation. BAFi-induced HIV-1 latency reversal was synergistically enhanced upon PKC pathway activation and HDAC-inhibition. Therefore BAFi's constitute a promising family of molecules for inclusion in therapeutic combinatorial HIV-1 latency reversal. BAF complex inhibitors (BAFi's) activate latent HIV-1 in cell line models of latency. BAFi's in combination with HDAC inhibitors and PKC activators synergistically activate latent HIV-1. The BAFi's PYR and CAPE reverse HIV-1 latency in primary cell models of latency and in cells obtained from HIV-1 patients.
Access to Combination antiretroviral therapy (cART) has made HIV-1 infection a chronic disease. However, cART is not curative, as a small number of infected cells harboring silent virus with potential to renew the infection persist despite cART. Efforts to cure HIV-1 include activation of these latent cells, making them susceptible to immune clearance. Here we describe the activity of BAF inhibitors in HIV-1 activation in in vitro models of HIV-1 latency as well as in cells obtained from HIV-1 infected patient volunteers. Our data highlight the clinical potential of BAF inhibitors for inclusion in combinatorial therapy to reverse HIV-1 latency.
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Key Words
- BAF complex
- BAF, BRG-Brahma Associated Factors
- BAF250a, BAF Associated Factor 250 a
- BAFi, BAF inhibitor
- BRG-1, Brahma Related Gene 1
- CAPE, caffeic acid phenetyl esther
- ChIP, Chromatin Immunoprecipitation
- Chromatin remodeling
- CycA, Cyclophilin A
- DHS-1, DNase Hypersensitive Site 1
- ES cells, embryonic stem cells
- FAIRE, Formaldehyde Assisted Isolation of Regulatory Elements
- FBS, Fetal Bovine Serum
- GFP, Green Fluorescent Protein
- HDAC, histone deacetylase
- HIV
- HIV-1, human immunodeficiency virus type 1
- IFNß, Interferon beta
- IL10, Interleukin 10
- IL12, Interleukin 12
- IL4, Interleukin 4
- IL6, Interleukin 6
- INI-1, Integrase Interactor 1
- IRES, Internal Ribosome Entry Site
- IκB-α, Inhibitor of NF-κB – alpha
- LRA, latency reversal agent
- LTR, Long Terminal Repeat
- Latency
- MIP26, Major Intrinsic Protein
- MMP9, Matrix Metallopeptidase 9
- NF-κB, Nuclear Factor Kappa-light-chain-enhancer of activated B cells
- PBMC, peripheral blood mononuclear cell
- PBS, Phosphate Buffered Saline
- PKC, Protein Kinase C
- PYR, Pyrimethamine
- RT-qPCR, Reverse Transcriptase, quantitative Polymerase Chain Reaction
- SAHA, Suberoylanilide Hydroxamic Acid
- SD, Standard Deviation
- SOCS3, Suppressor Of Cytokine Signaling 3
- TGF-ß, Transforming Growth Factor beta
- TLR2, Toll-like Receptor 2
- bp, base pairs
- cART, combination Antiretroviral Therapy
- latency reversal agents
- nuc, nucleosome
- siRNA, small interfering RNA
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Tyagi M, Weber J, Bukrinsky M, Simon GL. The effects of cocaine on HIV transcription. J Neurovirol 2015; 22:261-74. [PMID: 26572787 DOI: 10.1007/s13365-015-0398-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/01/2015] [Accepted: 10/21/2015] [Indexed: 11/29/2022]
Abstract
Illicit drug users are a high-risk population for infection with the human immunodeficiency virus (HIV). A strong correlation exists between prohibited drug use and an increased rate of HIV transmission. Cocaine stands out as one of the most frequently abused illicit drugs, and its use is correlated with HIV infection and disease progression. The central nervous system (CNS) is a common target for both drugs of abuse and HIV, and cocaine intake further accelerates neuronal injury in HIV patients. Although the high incidence of HIV infection in illicit drug abusers is primarily due to high-risk activities such as needle sharing and unprotected sex, several studies have demonstrated that cocaine enhances the rate of HIV gene expression and replication by activating various signal transduction pathways and downstream transcription factors. In order to generate mature HIV genomic transcript, HIV gene expression has to pass through both the initiation and elongation phases of transcription, which requires discrete transcription factors. In this review, we will provide a detailed analysis of the molecular mechanisms that regulate HIV transcription and discuss how cocaine modulates those mechanisms to upregulate HIV transcription and eventually HIV replication.
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Affiliation(s)
- Mudit Tyagi
- Division of Infectious Diseases, Department of Medicine, The George Washington University, 2300 Eye Street, N.W., Washington, DC, 20037, USA. .,Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, 20037, USA.
| | - Jaime Weber
- Division of Infectious Diseases, Department of Medicine, The George Washington University, 2300 Eye Street, N.W., Washington, DC, 20037, USA
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, 20037, USA
| | - Gary L Simon
- Division of Infectious Diseases, Department of Medicine, The George Washington University, 2300 Eye Street, N.W., Washington, DC, 20037, USA
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Bose D, Gagnon J, Chebloune Y. Comparative Analysis of Tat-Dependent and Tat-Deficient Natural Lentiviruses. Vet Sci 2015; 2:293-348. [PMID: 29061947 PMCID: PMC5644649 DOI: 10.3390/vetsci2040293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/24/2015] [Accepted: 08/24/2015] [Indexed: 01/10/2023] Open
Abstract
The emergence of human immunodeficiency virus (HIV) causing acquired immunodeficiency syndrome (AIDS) in infected humans has resulted in a global pandemic that has killed millions. HIV-1 and HIV-2 belong to the lentivirus genus of the Retroviridae family. This genus also includes viruses that infect other vertebrate animals, among them caprine arthritis-encephalitis virus (CAEV) and Maedi-Visna virus (MVV), the prototypes of a heterogeneous group of viruses known as small ruminant lentiviruses (SRLVs), affecting both goat and sheep worldwide. Despite their long host-SRLV natural history, SRLVs were never found to be responsible for immunodeficiency in contrast to primate lentiviruses. SRLVs only replicate productively in monocytes/macrophages in infected animals but not in CD4+ T cells. The focus of this review is to examine and compare the biological and pathological properties of SRLVs as prototypic Tat-independent lentiviruses with HIV-1 as prototypic Tat-dependent lentiviruses. Results from this analysis will help to improve the understanding of why and how these two prototypic lentiviruses evolved in opposite directions in term of virulence and pathogenicity. Results may also help develop new strategies based on the attenuation of SRLVs to control the highly pathogenic HIV-1 in humans.
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Affiliation(s)
- Deepanwita Bose
- Pathogénèse et Vaccination Lentivirales, PAVAL Lab., Université Joseph Fourier Grenoble 1, Bat. NanoBio2, 570 rue de la Chimie, BP 53, 38041, Grenoble Cedex 9, France.
| | - Jean Gagnon
- Pathogénèse et Vaccination Lentivirales, PAVAL Lab., Université Joseph Fourier Grenoble 1, Bat. NanoBio2, 570 rue de la Chimie, BP 53, 38041, Grenoble Cedex 9, France.
| | - Yahia Chebloune
- Pathogénèse et Vaccination Lentivirales, PAVAL Lab., Université Joseph Fourier Grenoble 1, Bat. NanoBio2, 570 rue de la Chimie, BP 53, 38041, Grenoble Cedex 9, France.
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Huang H, Santoso N, Power D, Simpson S, Dieringer M, Miao H, Gurova K, Giam CZ, Elledge SJ, Zhu J. FACT Proteins, SUPT16H and SSRP1, Are Transcriptional Suppressors of HIV-1 and HTLV-1 That Facilitate Viral Latency. J Biol Chem 2015; 290:27297-27310. [PMID: 26378236 DOI: 10.1074/jbc.m115.652339] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Indexed: 11/06/2022] Open
Abstract
Our functional genomic RNAi screens have identified the protein components of the FACT (facilitates chromatin transcription) complex, SUPT16H and SSRP1, as top host factors that negatively regulate HIV-1 replication. FACT interacts specifically with histones H2A/H2B to affect assembly and disassembly of nucleosomes, as well as transcription elongation. We further investigated the suppressive role of FACT proteins in HIV-1 transcription. First, depletion of SUPT16H or SSRP1 protein enhances Tat-mediated HIV-1 LTR (long terminal repeat) promoter activity. Second, HIV-1 Tat interacts with SUPT16H but not SSRP1 protein. However, both SUPT16H and SSRP1 are recruited to LTR promoter. Third, the presence of SUPT16H interferes with the association of Cyclin T1 (CCNT1), a subunit of P-TEFb, with the Tat-LTR axis. Removing inhibitory mechanisms to permit HIV-1 transcription is an initial and key regulatory step to reverse post-integrated latent HIV-1 proviruses for purging of reservoir cells. We therefore evaluated the role of FACT proteins in HIV-1 latency and reactivation. Depletion of SUPT16H or SSRP1 protein affects both HIV-1 transcriptional initiation and elongation and spontaneously reverses latent HIV-1 in U1/HIV and J-LAT cells. Similar effects were observed with a primary CD4+ T cell model of HIV-1 latency. FACT proteins also interfere with HTLV-1 Tax-LTR-mediated transcription and viral latency, indicating that they may act as general transcriptional suppressors for retroviruses. We conclude that FACT proteins SUPT16H and SSRP1 play a key role in suppressing HIV-1 transcription and promoting viral latency, which may serve as promising gene targets for developing novel HIV-1 latency-reversing agents.
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Affiliation(s)
- Huachao Huang
- Departments of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642
| | - Netty Santoso
- Departments of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642
| | - Derek Power
- Departments of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642
| | - Sydney Simpson
- the School of Arts and Sciences, University of Rochester, Rochester, New York 14627
| | - Michael Dieringer
- the School of Arts and Sciences, University of Rochester, Rochester, New York 14627
| | - Hongyu Miao
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York 14642
| | - Katerina Gurova
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Chou-Zen Giam
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Stephen J Elledge
- the Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, Boston, Massachusetts 02115; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Jian Zhu
- Departments of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642; Departments of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642.
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De Crignis E, Mahmoudi T. HIV eradication: combinatorial approaches to activate latent viruses. Viruses 2014; 6:4581-608. [PMID: 25421889 PMCID: PMC4246239 DOI: 10.3390/v6114581] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/01/2014] [Accepted: 11/13/2014] [Indexed: 12/11/2022] Open
Abstract
The concept of eradication of the Human Immune Deficiency Virus (HIV) from infected patients has gained much attention in the last few years. While combination Anti-Retroviral Therapy (c-ART) has been extremely effective in suppressing viral replication, it is not curative. This is due to the presence of a reservoir of latent HIV infected cells, which persist in the presence of c-ART. Recently, pharmaceutical approaches have focused on the development of molecules able to induce HIV-1 replication from latently infected cells in order to render them susceptible to viral cytopathic effects and host immune responses. Alternative pathways and transcription complexes function to regulate the activity of the HIV promoter and might serve as molecular targets for compounds to activate latent HIV. A combined therapy coupling various depressors and activators will likely be the most effective in promoting HIV replication while avoiding pleiotropic effects at the cellular level. Moreover, in light of differences among HIV subtypes and variability in integration sites, the combination of multiple agents targeting multiple pathways will increase likelihood of therapeutic effectiveness and prevent mutational escape. This review provides an overview of the mechanisms that can be targeted to induce HIV activation focusing on potential combinatorial approaches.
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Affiliation(s)
- Elisa De Crignis
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam 3015 CN, The Netherlands.
| | - Tokameh Mahmoudi
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam 3015 CN, The Netherlands.
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Colin L, Verdin E, Van Lint C. HIV-1 chromatin, transcription, and the regulatory protein Tat. Methods Mol Biol 2014; 1087:85-101. [PMID: 24158816 DOI: 10.1007/978-1-62703-670-2_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Upon integration into the host cell genome, the nucleosomal organization and epigenetic control of the HIV-1 provirus play an active role in its transcriptional regulation. Therefore, characterization of the chromatin changes that occur in the viral promoter region in response to different cellular stimuli or drug treatments represents an important aspect of our understanding of HIV-1 transcription. Moreover, the viral transactivator Tat protein potently activates HIV-1 transcription by recruiting the cellular positive transcription elongation factor p-TEFb to the TAR element located at the 5' end of all nascent viral transcripts, thereby promoting efficient elongation. This chapter describes two complementary techniques for analyzing chromatin structure. The first technique is called indirect end-labeling and uses DNase I, micrococcal nuclease (MNase) or specific restriction enzymes to provide a view of nucleosome positions and of nucleosome-free regions within genes that are usually associated with transcriptional regulatory elements. The second technique, called chromatin immunoprecipitation (ChIP), provides a detailed analysis of chromatin structure by determining the pattern of histone modification marks in the DNA region of interest and by identifying the transcription factors as well as the components of the transcriptional initiation and elongation machineries that are recruited in vivo to this chromosomal region.
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Affiliation(s)
- Laurence Colin
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), University of Brussels (ULB), Brussels, Belgium
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Dahiya S, Liu Y, Nonnemacher MR, Dampier W, Wigdahl B. CCAAT enhancer binding protein and nuclear factor of activated T cells regulate HIV-1 LTR via a novel conserved downstream site in cells of the monocyte-macrophage lineage. PLoS One 2014; 9:e88116. [PMID: 24551078 PMCID: PMC3925103 DOI: 10.1371/journal.pone.0088116] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 01/03/2014] [Indexed: 12/11/2022] Open
Abstract
Transcriptional control of the human immunodeficiency virus type 1 (HIV-1) promoter, the long terminal repeat (LTR), is achieved by interactions with cis-acting elements present both upstream and downstream of the start site. In silico transcription factor binding analysis of the HIV-1 subtype B LTR sequences revealed a potential downstream CCAAT enhancer binding protein (C/EBP) binding site. This binding site (+158 to+172), designated DS3, was found to be conserved in 67% of 3,858 unique subtype B LTR sequences analyzed in terms of nucleotide sequence as well as physical location in the LTR. DS3 was found to be well represented in other subtypes as well. Interestingly, DS3 overlaps with a previously identified region that bind members of the nuclear factor of activated T cells (NFAT) family of proteins. NFATc2 exhibited a higher relative affinity for DS3 as compared with members of the C/EBP family (C/EBP α and β). DS3 was able to compete efficiently with the low-affinity upstream C/EBP binding site I with respect to C/EBP binding, suggesting utilization of both NFAT and C/EBP. Moreover, cyclosporine A treatment, which has been shown to prevent dephosphorylation and nuclear translocation of NFAT isoforms, resulted in enhanced C/EBPα binding. The interactions at DS3 were also validated in an integrated HIV-1 LTR in chronically infected U1 cells. A binding knockout of DS3 demonstrated reduced HIV-1 LTR-directed transcription under both basal and interleukin-6-stimulated conditions only in cells of the monocyte-macrophage lineage cells and not in cells of T-cell origin. Thus, the events at DS3 positively regulate the HIV-1 promoter in cells of the monocyte-macrophage lineage.
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Affiliation(s)
- Satinder Dahiya
- 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, Pennsylvania, United States of America
| | - Yujie Liu
- 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, Pennsylvania, United States of America
| | - Michael R. Nonnemacher
- 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, Pennsylvania, United States of America
| | - Will Dampier
- 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, Pennsylvania, United States of America
| | - Brian Wigdahl
- 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, Pennsylvania, United States of America
- * E-mail:
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48
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Matsuoka M, Yasunaga JI. Human T-cell leukemia virus type 1: replication, proliferation and propagation by Tax and HTLV-1 bZIP factor. Curr Opin Virol 2013; 3:684-91. [PMID: 24060211 DOI: 10.1016/j.coviro.2013.08.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/20/2013] [Accepted: 08/21/2013] [Indexed: 12/13/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) spreads primarily by cell-to-cell transmission. Therefore, HTLV-1 promotes the proliferation of infected cells to facilitate transmission. In HTLV-1 infected individuals, the provirus is present mainly in effector/memory T cells and Foxp3+ T cells. Recent study suggests that this immunophenotype is acquired by infected cells through the function of HTLV-1 bZIP factor (HBZ). Tax, which is encoded by the plus strand, is crucial for viral replication and de novo infection, while HBZ, encoded by the minus strand, is important for proliferation of infected cells. Importantly, HBZ and Tax have opposing functions in most transcription pathways. HBZ and Tax cooperate in elaborate ways to permit viral replication, proliferation of infected cells and propagation of the virus.
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Affiliation(s)
- Masao Matsuoka
- Institute for Virus Research, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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Abstract
The HIV/AIDS field is gaining momentum in the goal of finding a functional cure for HIV infection by utilizing strategies that specifically reactivate the latent viral reservoir in combination with the HAART regimen to prevent further viral spread. Small-molecule inhibitors such as histone deacetylase (HDAC) and bromodomain and extraterminal (BET) inhibitors can successfully activate HIV transcription and reverse viral latency in clonal cell lines. However, in resting CD4+ T cells, thought to be the principal physiological reservoir of latent HIV, their effect in reactivating the viral reservoir is more variable. It is possible that the discrepant responsiveness of quiescent primary CD4+ T cells to HDAC and BET inhibitors could be attributed to the limiting levels of P-TEFb, a key viral transcription host cofactor, in these cells. In this review, we discuss the role of P-TEFb and the necessity for its mobilization in stimulating viral reactivation from latency upon treatment with HDAC and BET inhibitors.
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Affiliation(s)
- Sona Budhiraja
- Department of Molecular Microbiology & Virology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Andrew P Rice
- Department of Molecular Microbiology & Virology, Baylor College of Medicine, Houston, TX 77030, USA
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50
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Groen JN, Morris KV. Chromatin, non-coding RNAs, and the expression of HIV. Viruses 2013; 5:1633-45. [PMID: 23812489 PMCID: PMC3738951 DOI: 10.3390/v5071633] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 12/20/2022] Open
Abstract
HIV is a chronic viral infection affecting an estimated 34 million people worldwide. Current therapies employ the use of a cocktail of antiretroviral medications to reduce the spread and effects of HIV, however complete eradication from an individual currently remains unattainable. Viral latency and regulation of gene expression is a key consideration when developing effective treatments. While our understanding of these processes remains incomplete new developments suggest that non-coding RNA (ncRNA) mediated regulation may provide an avenue to controlling both viral expression and latency. Here we discuss the importance of known regulatory mechanisms and suggest directions for further study, in particular the use ncRNAs in controlling HIV expression.
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Affiliation(s)
- Jessica N. Groen
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia; E-Mail:
| | - Kevin V. Morris
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia; E-Mail:
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +61-2-9385-2019
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