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Zareie AR, Dabral P, Verma SC. G-Quadruplexes in the Regulation of Viral Gene Expressions and Their Impacts on Controlling Infection. Pathogens 2024; 13:60. [PMID: 38251367 PMCID: PMC10819198 DOI: 10.3390/pathogens13010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/23/2024] Open
Abstract
G-quadruplexes (G4s) are noncanonical nucleic acid structures that play significant roles in regulating various biological processes, including replication, transcription, translation, and recombination. Recent studies have identified G4s in the genomes of several viruses, such as herpes viruses, hepatitis viruses, and human coronaviruses. These structures are implicated in regulating viral transcription, replication, and virion production, influencing viral infectivity and pathogenesis. G4-stabilizing ligands, like TMPyP4, PhenDC3, and BRACO19, show potential antiviral properties by targeting and stabilizing G4 structures, inhibiting essential viral life-cycle processes. This review delves into the existing literature on G4's involvement in viral regulation, emphasizing specific G4-stabilizing ligands. While progress has been made in understanding how these ligands regulate viruses, further research is needed to elucidate the mechanisms through which G4s impact viral processes. More research is necessary to develop G4-stabilizing ligands as novel antiviral agents. The increasing body of literature underscores the importance of G4s in viral biology and the development of innovative therapeutic strategies against viral infections. Despite some ligands' known regulatory effects on viruses, a deeper comprehension of the multifaceted impact of G4s on viral processes is essential. This review advocates for intensified research to unravel the intricate relationship between G4s and viral processes, paving the way for novel antiviral treatments.
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Affiliation(s)
| | | | - Subhash C. Verma
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, 1664 N Virginia Street, Reno, NV 89557, USA; (A.R.Z.); (P.D.)
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2
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Allen AG, Chung CH, Worrell SD, Nwaozo G, Madrid R, Mele AR, Dampier W, Nonnemacher MR, Wigdahl B. Assessment of anti-HIV-1 guide RNA efficacy in cells containing the viral target sequence, corresponding gRNA, and CRISPR/Cas9. Front Genome Ed 2023; 5:1101483. [PMID: 37124096 PMCID: PMC10134072 DOI: 10.3389/fgeed.2023.1101483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/20/2023] [Indexed: 05/02/2023] Open
Abstract
The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 gene editing system has been shown to be effective at inhibiting human immunodeficiency virus type 1 (HIV-1). Studies have not consistently used a trackable dual reporter system to determine what cells received the Cas9/gRNA to determine the overall knockdown of HIV. Some studies have used stably transduced cells under drug selection to accomplish this goal. Here a two-color system was used that allows tracking of viral protein expression and which cells received the CRISPR/Cas9 system. These experiments ensured that each gRNA used was a perfect match to the intended target to remove this variable. The data showed that gRNAs targeting the transactivation response element (TAR) region or other highly conserved regions of the HIV-1 genome were effective at stopping viral gene expression, with multiple assays demonstrating greater than 95 percent reduction. Conversely, gRNAs targeting conserved sites of the 5' portion of the U3 region were largely ineffective, demonstrating that the location of edits in the long terminal repeat (LTR) matter with respect to function. In addition, it was observed that a gRNA targeting Tat was effective in a T-cell model of HIV-1 latency. Taken together, these studies demonstrated gRNAs designed to highly conserved functional regions have near 100% efficacy in vitro in cells known to have received the Cas9/gRNA pair.
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Affiliation(s)
- Alexander G. Allen
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Cheng-Han Chung
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Stephen D. Worrell
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Glad Nwaozo
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Rebekah Madrid
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Anthony R. Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Will Dampier
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Michael R. Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- Center for Molecular Virology and Gene Therapy, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, United States
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
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3
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Balance between Retroviral Latency and Transcription: Based on HIV Model. Pathogens 2020; 10:pathogens10010016. [PMID: 33383617 PMCID: PMC7824405 DOI: 10.3390/pathogens10010016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 01/04/2023] Open
Abstract
The representative of the Lentivirus genus is the human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome (AIDS). To date, there is no cure for AIDS because of the existence of the HIV-1 reservoir. HIV-1 infection can persist for decades despite effective antiretroviral therapy (ART), due to the persistence of infectious latent viruses in long-lived resting memory CD4+ T cells, macrophages, monocytes, microglial cells, and other cell types. However, the biology of HIV-1 latency remains incompletely understood. Retroviral long terminal repeat region (LTR) plays an indispensable role in controlling viral gene expression. Regulation of the transcription initiation plays a crucial role in establishing and maintaining a retrovirus latency. Whether and how retroviruses establish latency and reactivate remains unclear. In this article, we describe what is known about the regulation of LTR-driven transcription in HIV-1, that is, the cis-elements present in the LTR, the role of LTR transcription factor binding sites in LTR-driven transcription, the role of HIV-1-encoded transactivator protein, hormonal effects on virus transcription, impact of LTR variability on transcription, and epigenetic control of retrovirus LTR. Finally, we focus on a novel clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/dCas9)-based strategy for HIV-1 reservoir purging.
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Regulation of Expression and Latency in BLV and HTLV. Viruses 2020; 12:v12101079. [PMID: 32992917 PMCID: PMC7601775 DOI: 10.3390/v12101079] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotrophic virus type 1 (HTLV-1) and Bovine leukemia virus (BLV) belong to the Deltaretrovirus genus. HTLV-1 is the etiologic agent of the highly aggressive and currently incurable cancer adult T-cell leukemia (ATL) and a neurological disease HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). BLV causes neoplastic proliferation of B cells in cattle: enzootic bovine leucosis (EBL). Despite the severity of these conditions, infection by HTLV-1 and BLV appear in most cases clinically asymptomatic. These viruses can undergo latency in their hosts. The silencing of proviral gene expression and maintenance of latency are central for the establishment of persistent infection, as well as for pathogenesis in vivo. In this review, we will present the mechanisms that control proviral activation and retroviral latency in deltaretroviruses, in comparison with other exogenous retroviruses. The 5′ long terminal repeats (5′-LTRs) play a main role in controlling viral gene expression. While the regulation of transcription initiation is a major mechanism of silencing, we discuss topics that include (i) the epigenetic control of the provirus, (ii) the cis-elements present in the LTR, (iii) enhancers with cell-type specific regulatory functions, (iv) the role of virally-encoded transactivator proteins, (v) the role of repressors in transcription and silencing, (vi) the effect of hormonal signaling, (vii) implications of LTR variability on transcription and latency, and (viii) the regulatory role of non-coding RNAs. Finally, we discuss how a better understanding of these mechanisms may allow for the development of more effective treatments against Deltaretroviruses.
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Genetic variability of the U5 and downstream sequence of major HIV-1 subtypes and circulating recombinant forms. Sci Rep 2020; 10:13214. [PMID: 32764600 PMCID: PMC7411029 DOI: 10.1038/s41598-020-70083-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 07/03/2020] [Indexed: 11/08/2022] Open
Abstract
The critical role of the regulatory elements at the 5′ end of the HIV-1 genome in controlling the life cycle of HIV-1 indicates that this region significantly influences virus fitness and its biological properties. In this study, we performed a detailed characterization of strain-specific variability of sequences from the U5 to upstream of the gag gene start codon of diverse HIV-1 strains by using next-generation sequencing (NGS) techniques. Overall, we found that this region of the HIV-1 genome displayed a low degree of intra-strain variability. On the other hand, inter-strain variability was found to be as high as that reported for gag and env genes (13–17%). We observed strain-specific single point and clustered mutations in the U5, PBS, and gag leader sequences (GLS), generating potential strain-specific transcription factor binding sites (TFBS). Using an infrared gel shift assay, we demonstrated the presence of potential TFBS such as E-box in CRF22_01A, and Stat 6 in subtypes A and G, as well as in their related CRFs. The strain-specific variation found in the sequence corresponding at the RNA level to functional domains of the 5ʹ UTR, could also potentially impact the secondary/tertiary structural rearrangement of this region. Thus, the variability observed in this 5′ end of the genomic region of divergent HIV-1 strains strongly suggests that functions of this region might be affected in a strain-specific manner. Our findings provide new insights into DNA–protein interactions that regulate HIV-1 replication and the influence of strain characterization on the biology of HIV-1 infection.
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Chung CH, Allen AG, Atkins AJ, Sullivan NT, Homan G, Costello R, Madrid R, Nonnemacher MR, Dampier W, Wigdahl B. Safe CRISPR-Cas9 Inhibition of HIV-1 with High Specificity and Broad-Spectrum Activity by Targeting LTR NF-κB Binding Sites. MOLECULAR THERAPY-NUCLEIC ACIDS 2020; 21:965-982. [PMID: 32818921 PMCID: PMC7452136 DOI: 10.1016/j.omtn.2020.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/22/2020] [Accepted: 07/08/2020] [Indexed: 12/26/2022]
Abstract
Viral latency of human immunodeficiency virus type 1 (HIV-1) has become a major hurdle to a cure in the highly effective antiretroviral therapy (ART) era. The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system has successfully been demonstrated to excise or inactivate integrated HIV-1 provirus from infected cells by targeting the long terminal repeat (LTR) region. However, the guide RNAs (gRNAs) have classically avoided transcription factor binding sites (TFBSs) that are readily observed and known to be important in human promoters. Although conventionally thought unfavorable due to potential impact on human promoters, our computational pipeline identified gRNA sequences that were predicted to inactivate HIV-1 transcription by targeting the nuclear factor κB (NF-κB) binding sites (gNFKB0, gNFKB1) with a high safety profile (lack of predicted or observed human edits) and broad-spectrum activity (predicted coverage of known viral sequences). Genome-wide, unbiased identification of double strand breaks (DSBs) enabled by sequencing (GUIDE-seq) showed that the gRNAs targeting NF-κB binding sites had no detectable CRISPR-induced off-target edits in HeLa cells. 5′ LTR-driven HIV-1 transcription was significantly reduced in three HIV-1 reporter cell lines. These results demonstrate a working model to specifically target well-known TFBSs in the HIV-1 LTR that are readily observed in human promoters to reduce HIV-1 transcription with a high-level safety profile and broad-spectrum activity.
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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
| | - Andrew J 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
| | - 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
| | - Greg Homan
- 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
| | - Robert Costello
- 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
| | - Rebekah Madrid
- 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
| | - 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
| | - 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.
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7
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Blackard JT, Davies SM, Laskin BL. BK polyomavirus diversity-Why viral variation matters. Rev Med Virol 2020; 30:e2102. [PMID: 32128960 DOI: 10.1002/rmv.2102] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 02/06/2023]
Abstract
BK polyomavirus (BKPyV or BKV) is a non-enveloped, circular double-stranded DNA virus that may exceed 80% seroprevalence in adults. BKV infection typically occurs during childhood, and the majority of adults are latently infected. While BKV infection is rarely associated with clinical disease in most individuals, in immunosuppressed individuals, reactivation may cause kidney (BK-associated nephropathy) or bladder (hemorrhagic cystitis and ureteral stenosis) injury. No antiviral therapies have been approved for the treatment of BKV infection. Reducing immunosuppression is the most effective therapy, although this is not feasible in many patients. Thus, a robust understanding of viral pathogenesis and viral diversity remains important for the development of future therapeutic strategies. Studies of BKV diversity are quite sparse compared to other common viral infections; thus, much of our understanding of BVK variability and evolution relies heavily analogous studies of other viruses such as HIV or viral hepatitis. We provide a comprehensive review of BKV diversity at the population and individual level with careful consideration of how viral variability may impact viral replication, pathogenesis, tropism, and protein function. We also discuss a number of outstanding questions related to BK virus diversity that should be explored rigorously in future studies.
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Affiliation(s)
- Jason T Blackard
- Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Stella M Davies
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Benjamin L Laskin
- Division of Nephrology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Link RW, Nonnemacher MR, Wigdahl B, Dampier W. Prediction of Human Immunodeficiency Virus Type 1 Subtype-Specific Off-Target Effects Arising from CRISPR-Cas9 Gene Editing Therapy. CRISPR J 2018; 1:294-302. [PMID: 31021222 DOI: 10.1089/crispr.2018.0020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chronic human immunodeficiency virus type 1 (HIV-1) disease is characterized by the retention of provirus within latently infected cells. Anti-HIV-1 CRISPR-Cas9 gene editing is an attractive strategy to excise or inactivate the HIV-1 genome. Recent strategies have focused on designing gRNAs that target the long terminal repeat (LTR) because 5' and 3' LTR symmetry can facilitate proviral excision. However, the promiscuity of CRISPR-Cas9 gene editing system necessitates the investigation of potential off-target effects. Here, potential gRNAs designed from HIV-1 phylogenetic subtypes using the CRISPRseek tool were investigated. Across the LTR, it was found that certain regions show higher human homology than others. When using recommended cutoffs, 96.40% of gRNAs were predicted to have no high probability off-target effects. Given this observation, while high-probability off-target effects are a potential danger, they can be avoided with proper gRNA design.
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Affiliation(s)
- Robert W Link
- 1 School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania
| | - Michael R Nonnemacher
- 2 Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,3 Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania.,4 Sidney Kimmel Cancer Center, Thomas Jefferson University , Philadelphia, Pennsylvania.,5 Center for Genomic Sciences, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Brian Wigdahl
- 2 Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,3 Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania.,4 Sidney Kimmel Cancer Center, Thomas Jefferson University , Philadelphia, Pennsylvania.,5 Center for Genomic Sciences, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Will Dampier
- 1 School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania.,2 Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,3 Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
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Mbondji-wonje C, Dong M, Wang X, Zhao J, Ragupathy V, Sanchez AM, Denny TN, Hewlett I. Distinctive variation in the U3R region of the 5' Long Terminal Repeat from diverse HIV-1 strains. PLoS One 2018; 13:e0195661. [PMID: 29664930 PMCID: PMC5903597 DOI: 10.1371/journal.pone.0195661] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/27/2018] [Indexed: 12/14/2022] Open
Abstract
Functional mapping of the 5’LTR has shown that the U3 and the R regions (U3R) contain a cluster of regulatory elements involved in the control of HIV-1 transcription and expression. As the HIV-1 genome is characterized by extensive variability, here we aimed to describe mutations in the U3R from various HIV-1 clades and CRFs in order to highlight strain specific differences that may impact the biological properties of diverse HIV-1 strains. To achieve our purpose, the U3R sequence of plasma derived virus belonging to different clades (A1, B, C, D, F2) and recombinants (CRF02_AG, CRF01_AE and CRF22_01A1) was obtained using Illumina technology. Overall, the R region was very well conserved among and across different strains, while in the U3 region the average inter-strains nucleotide dissimilarity was up to 25%. The TAR hairpin displayed a strain-distinctive cluster of mutations affecting the bulge and the loop, but mostly the stem. Like in previous studies we found a TATAA motif in U3 promoter region from the majority of HIV-1 strains and a TAAAA motif in CRF01_AE; but also in LTRs from CRF22_01A1 isolates. Although LTRs from CRF22_01A1 specimens were assigned CRF01_AE, they contained two NF-kB sites instead of the single TFBS described in CRF01_AE. Also, as previously describe in clade C isolates, we found no C/EBP binding site directly upstream of the enhancer region in CRF22_01A1 specimens. In our study, one-third of CRF02_AG LTRs displayed three NF-kB sites which have been mainly described in clade C isolates. Overall, the number, location and binding patterns of potential regulatory elements found along the U3R might be specific to some HIV-1 strains such as clade F2, CRF02_AG, CRF01_AE and CRF22_01A1. These features may be worth consideration as they may be involved in distinctive regulation of HIV-1 transcription and replication by different and diverse infecting strains.
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Affiliation(s)
- Christelle Mbondji-wonje
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
- Department of Molecular Biology, Faculty of Medicine, Pharmacy and Biomedical sciences, University of Douala, Douala, Cameroon
- * E-mail: (CM); (IH)
| | - Ming Dong
- U.S. Military HIV Research Program, Silver Spring, Maryland United States of America
| | - Xue Wang
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Jiangqin Zhao
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Viswanath Ragupathy
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Ana M. Sanchez
- Department of Medicine, Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Thomas N. Denny
- Department of Medicine, Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Indira Hewlett
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail: (CM); (IH)
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10
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Qu D, Li C, Sang F, Li Q, Jiang ZQ, Xu LR, Guo HJ, Zhang C, Wang JH. The variances of Sp1 and NF-κB elements correlate with the greater capacity of Chinese HIV-1 B'-LTR for driving gene expression. Sci Rep 2016; 6:34532. [PMID: 27698388 PMCID: PMC5048295 DOI: 10.1038/srep34532] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 09/15/2016] [Indexed: 12/28/2022] Open
Abstract
The 5' end of HIV-1 long terminal repeat (LTR) serves as a promoter that plays an essential role in driving viral gene transcription. Manipulation of HIV-1 LTR provides a potential therapeutic strategy for suppressing viral gene expression or excising integrated provirus. Subtype-specific genetic diversity in the LTR region has been observed. The minor variance of LTR, particularly in the transcription factor binding sites, can have a profound impact on its activity. However, the LTR profiles from major endemic Chinese subtypes are not well characterized. Here, by characterizing the sequences and functions of LTRs from endemic Chinese HIV-1 subtypes, we showed that nucleotide variances of Sp1 core promoter and NF-κB element are associated with varied LTR capacity for driving viral gene transcription. The greater responsiveness of Chinese HIV-1 B'-LTR for driving viral gene transcription upon stimulation is associated with an increased level of viral reactivation. Moreover, we demonstrated that the introduction of CRISPR/dead Cas9 targeting Sp1 or NF-κB element suppressed viral gene expression. Taken together, our study characterized LTRs from endemic HIV-1 subtypes in China and suggests a potential target for the suppression of viral gene expression and a novel strategy that facilitates the accomplishment of a functional cure.
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Affiliation(s)
- Di Qu
- CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Chuan Li
- CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Feng Sang
- Key laboratory of Prevention and Treatment with Traditional Chinese Medicine on Viral Infection Disease, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Qiang Li
- Key laboratory of Prevention and Treatment with Traditional Chinese Medicine on Viral Infection Disease, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Zhi-Qiang Jiang
- Key laboratory of Prevention and Treatment with Traditional Chinese Medicine on Viral Infection Disease, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Li-Ran Xu
- Key laboratory of Prevention and Treatment with Traditional Chinese Medicine on Viral Infection Disease, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Hui-Jun Guo
- Key laboratory of Prevention and Treatment with Traditional Chinese Medicine on Viral Infection Disease, the First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Chiyu Zhang
- CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Jian-Hua Wang
- CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
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11
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Toll-interacting protein inhibits HIV-1 infection and regulates viral latency. Biochem Biophys Res Commun 2016; 475:161-8. [PMID: 27181351 DOI: 10.1016/j.bbrc.2016.05.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 05/12/2016] [Indexed: 12/31/2022]
Abstract
HIV-1 latency is mainly characterized by a reversible silencing of long-terminal repeat (LTR)-driven transcription of provirus. The existing of repressive factors has been described to contribute to transcription silencing of HIV-1. Toll-interacting protein (Tollip) has been identified as a repressor of Toll like receptors (TLR)-mediated signaling. Our previous study has found that Tollip inhibited NF-κB-dependent HIV-1 promoter LTR-driven transcription, indicating the potential role of Tollip in governing viral latency. In this study, by using HIV-1 latently infected Jurkat T-cell and central memory CD4(+) T-cells, we demonstrate the role of Tollip in regulating HIV-1 latency, as the knock-down of Tollip promoted HIV-1 reactivation from both HIV-1 latently infected Jurkat CD4(+) T cells and primary central memory T cells (TCM). Moreover, we found that the activities of LTRs derived from multiple HIV-1 subtypes could be repressed by Tollip; Knock-down of Tollip promoted HIV-1 transcription and infection in CD4(+) T cells. Our data indicate a key role of Tollip in suppressing HIV-1 infection and regulating viral latency, which provides a potential host target for combating HIV-1 infection and latency.
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12
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Antell GC, Dampier W, Aiamkitsumrit B, Nonnemacher MR, Jacobson JM, Pirrone V, Zhong W, Kercher K, Passic S, Williams JW, Schwartz G, Hershberg U, Krebs FC, Wigdahl B. Utilization of HIV-1 envelope V3 to identify X4- and R5-specific Tat and LTR sequence signatures. Retrovirology 2016; 13:32. [PMID: 27143130 PMCID: PMC4855882 DOI: 10.1186/s12977-016-0266-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 04/20/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND HIV-1 entry is a receptor-mediated process directed by the interaction of the viral envelope with the host cell CD4 molecule and one of two co-receptors, CCR5 or CXCR4. The amino acid sequence of the third variable (V3) loop of the HIV-1 envelope is highly predictive of co-receptor utilization preference during entry, and machine learning predictive algorithms have been developed to characterize sequences as CCR5-utilizing (R5) or CXCR4-utilizing (X4). It was hypothesized that while the V3 loop is predominantly responsible for determining co-receptor binding, additional components of the HIV-1 genome may contribute to overall viral tropism and display sequence signatures associated with co-receptor utilization. RESULTS The accessory protein Tat and the HlV-1 long terminal repeat (LTR) were analyzed with respect to genetic diversity and compared by Jensen-Shannon divergence which resulted in a correlation with both mean genetic diversity as well as the absolute difference in genetic diversity between R5- and X4-genome specific trends. As expected, the V3 domain of the gp120 protein was enriched with statistically divergent positions. Statistically divergent positions were also identified in Tat amino acid sequences within the transactivation and TAR-binding domains, and in nucleotide positions throughout the LTR. We further analyzed LTR sequences for putative transcription factor binding sites using the JASPAR transcription factor binding profile database and found several putative differences in transcription factor binding sites between R5 and X4 HIV-1 genomes, specifically identifying the C/EBP sites I and II, and Sp site III to differ with respect to sequence configuration for R5 and X4 LTRs. CONCLUSION These observations support the hypothesis that co-receptor utilization coincides with specific genetic signatures in HIV-1 Tat and the LTR, likely due to differing transcriptional regulatory mechanisms and selective pressures applied within specific cellular targets during the course of productive HIV-1 infection.
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Affiliation(s)
- Gregory C Antell
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.,School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Will Dampier
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.,School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Benjamas Aiamkitsumrit
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jeffrey M Jacobson
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Division of Infectious Diseases and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Vanessa Pirrone
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Wen Zhong
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Katherine Kercher
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Shendra Passic
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jean W Williams
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gregory Schwartz
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Uri Hershberg
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Fred C Krebs
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA. .,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA. .,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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HIV-1 Promoter Single Nucleotide Polymorphisms Are Associated with Clinical Disease Severity. PLoS One 2016; 11:e0150835. [PMID: 27100290 PMCID: PMC4839606 DOI: 10.1371/journal.pone.0150835] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/20/2016] [Indexed: 12/13/2022] Open
Abstract
The large majority of human immunodeficiency virus type 1 (HIV-1) markers of disease progression/severity previously identified have been associated with alterations in host genetic and immune responses, with few studies focused on viral genetic markers correlate with changes in disease severity. This study presents a cross-sectional/longitudinal study of HIV-1 single nucleotide polymorphisms (SNPs) contained within the viral promoter or long terminal repeat (LTR) in patients within the Drexel Medicine CNS AIDS Research and Eradication Study (CARES) Cohort. HIV-1 LTR SNPs were found to associate with the classical clinical disease parameters CD4+ T-cell count and log viral load. They were found in both defined and undefined transcription factor binding sites of the LTR. A novel SNP identified at position 108 in a known COUP (chicken ovalbumin upstream promoter)/AP1 transcription factor binding site was significantly correlated with binding phenotypes that are potentially the underlying cause of the associated clinical outcome (increase in viral load and decrease in CD4+ T-cell count).
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14
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Impact of viral activators and epigenetic regulators on HIV-1 LTRs containing naturally occurring single nucleotide polymorphisms. BIOMED RESEARCH INTERNATIONAL 2015; 2015:320642. [PMID: 25629043 PMCID: PMC4299542 DOI: 10.1155/2015/320642] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 09/29/2014] [Accepted: 10/14/2014] [Indexed: 12/17/2022]
Abstract
Following human immunodeficiency virus type 1 (HIV-1) integration into host cell DNA, the viral promoter can become transcriptionally silent in the absence of appropriate signals and factors. HIV-1 gene expression is dependent on regulatory elements contained within the long terminal repeat (LTR) that drive the synthesis of viral RNAs and proteins through interaction with multiple host and viral factors. Previous studies identified single nucleotide polymorphisms (SNPs) within CCAAT/enhancer binding protein (C/EBP) site I and Sp site III (3T, C-to-T change at position 3, and 5T, C-to-T change at position 5 of the binding site, respectively, when compared to the consensus B sequence) that are low affinity binding sites and correlate with more advanced stages of HIV-1 disease. Stably transfected cell lines containing the wild type, 3T, 5T, and 3T5T LTRs were developed utilizing bone marrow progenitor, T, and monocytic cell lines to explore the LTR phenotypes associated with these genotypic changes from an integrated chromatin-based microenvironment. Results suggest that in nonexpressing cell clones LTR-driven gene expression occurs in a SNP-specific manner in response to LTR activation or treatment with trichostatin A treatment, indicating a possible cell type and SNP-specific mechanism behind the epigenetic control of LTR activation.
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15
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Defining differential genetic signatures in CXCR4- and the CCR5-utilizing HIV-1 co-linear sequences. PLoS One 2014; 9:e107389. [PMID: 25265194 PMCID: PMC4180074 DOI: 10.1371/journal.pone.0107389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/07/2014] [Indexed: 11/29/2022] Open
Abstract
The adaptation of human immunodeficiency virus type-1 (HIV-1) to an array of physiologic niches is advantaged by the plasticity of the viral genome, encoded proteins, and promoter. CXCR4-utilizing (X4) viruses preferentially, but not universally, infect CD4+ T cells, generating high levels of virus within activated HIV-1-infected T cells that can be detected in regional lymph nodes and peripheral blood. By comparison, the CCR5-utilizing (R5) viruses have a greater preference for cells of the monocyte-macrophage lineage; however, while R5 viruses also display a propensity to enter and replicate in T cells, they infect a smaller percentage of CD4+ T cells in comparison to X4 viruses. Additionally, R5 viruses have been associated with viral transmission and CNS disease and are also more prevalent during HIV-1 disease. Specific adaptive changes associated with X4 and R5 viruses were identified in co-linear viral sequences beyond the Env-V3. The in silico position-specific scoring matrix (PSSM) algorithm was used to define distinct groups of X4 and R5 sequences based solely on sequences in Env-V3. Bioinformatic tools were used to identify genetic signatures involving specific protein domains or long terminal repeat (LTR) transcription factor sites within co-linear viral protein R (Vpr), trans-activator of transcription (Tat), or LTR sequences that were preferentially associated with X4 or R5 Env-V3 sequences. A number of differential amino acid and nucleotide changes were identified across the co-linear Vpr, Tat, and LTR sequences, suggesting the presence of specific genetic signatures that preferentially associate with X4 or R5 viruses. Investigation of the genetic relatedness between X4 and R5 viruses utilizing phylogenetic analyses of complete sequences could not be used to definitively and uniquely identify groups of R5 or X4 sequences; in contrast, differences in the genetic diversities between X4 and R5 were readily identified within these co-linear sequences in HIV-1-infected patients.
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16
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Churchill MJ, Cowley DJ, Wesselingh SL, Gorry PR, Gray LR. HIV-1 transcriptional regulation in the central nervous system and implications for HIV cure research. J Neurovirol 2014; 21:290-300. [PMID: 25060300 DOI: 10.1007/s13365-014-0271-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/25/2014] [Accepted: 06/27/2014] [Indexed: 12/15/2022]
Abstract
Human immunodeficiency virus type-1 (HIV-1) invades the central nervous system (CNS) during acute infection which can result in HIV-associated neurocognitive disorders in up to 50% of patients, even in the presence of combination antiretroviral therapy (cART). Within the CNS, productive HIV-1 infection occurs in the perivascular macrophages and microglia. Astrocytes also become infected, although their infection is restricted and does not give rise to new viral particles. The major barrier to the elimination of HIV-1 is the establishment of viral reservoirs in different anatomical sites throughout the body and viral persistence during long-term treatment with cART. While the predominant viral reservoir is believed to be resting CD4(+) T cells in the blood, other anatomical compartments including the CNS, gut-associated lymphoid tissue, bone marrow, and genital tract can also harbour persistently infected cellular reservoirs of HIV-1. Viral latency is predominantly responsible for HIV-1 persistence and is most likely governed at the transcriptional level. Current clinical trials are testing transcriptional activators, in the background of cART, in an attempt to purge these viral reservoirs and reverse viral latency. These strategies aim to activate viral transcription in cells constituting the viral reservoir, so they can be recognised and cleared by the immune system, while new rounds of infection are blocked by co-administration of cART. The CNS has several unique characteristics that may result in differences in viral transcription and in the way latency is established. These include CNS-specific cell types, different transcription factors, altered immune surveillance, and reduced antiretroviral drug bioavailability. A comprehensive understanding of viral transcription and latency in the CNS is required in order to determine treatment outcomes when using transcriptional activators within the CNS.
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Affiliation(s)
- Melissa J Churchill
- Center for Biomedical Research, Burnet Institute, 85 Commercial Rd, Melbourne, 3004, Victoria, Australia,
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17
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Shah S, Alexaki A, Pirrone V, Dahiya S, Nonnemacher MR, Wigdahl B. Functional properties of the HIV-1 long terminal repeat containing single-nucleotide polymorphisms in Sp site III and CCAAT/enhancer binding protein site I. Virol J 2014; 11:92. [PMID: 24886416 PMCID: PMC4047001 DOI: 10.1186/1743-422x-11-92] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 04/25/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND HIV-1 gene expression is driven by the long terminal repeat (LTR), which contains many binding sites shown to interact with an array of host and viral factors. Selective pressures within the host as well as the low fidelity of reverse transcriptase lead to changes in the relative prevalence of genetic variants within the HIV-1 genome, including the LTR, resulting in viral quasispecies that can be differentially regulated and can potentially establish niches within specific cell types and tissues. METHODS Utilizing flow cytometry and electromobility shift assays, specific single-nucleotide sequence polymorphisms (SNPs) were shown to alter both the phenotype of LTR-driven transcription and reactivation. Additional studies also demonstrated differential loading of transcription factors to probes derived from the double-variant LTR as compared to probes from the wild type. RESULTS This study has identified specific SNPs within CCAAT/enhancer binding protein (C/EBP) site I and Sp site III (3 T, C-to-T change at position 3, and 5 T, C-to-T change at position 5 of the binding site, respectively) that alter LTR-driven gene transcription and may alter the course of viral latency and reactivation. The HIV-1 LAI LTRs containing the SNPs of interest were coupled to a plasmid encoding green fluorescent protein (GFP), and polyclonal HIV-1 LTR-GFP stable cell lines utilizing bone marrow progenitor, T, and monocytic cell lines were constructed and utilized to explore the LTR phenotype associated with these genotypic changes. CONCLUSIONS Although the 3 T and 5 T SNPs have been shown to be low-affinity binding sites, the fact that they can still result in effective HIV-1 LTR-driven gene expression, particularly within the TF-1 cell line, has suggested that the low binding site affinities associated with the 3 T C/EBP site I and 5 T Sp site III are potentially compensated for by the interaction of nuclear factor-κB with its corresponding binding sites under selected physiological and cellular conditions. Additionally, tumor necrosis factor-α and Tat can enhance basal transcription of each SNP-specific HIV-1 LTR; however, differential regulation of the LTR is both SNP- and cell type-specific.
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Affiliation(s)
- Sonia Shah
- 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 19102, USA
| | - Aikaterini Alexaki
- 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 19102, USA
| | - Vanessa Pirrone
- 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 19102, USA
| | - 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 19102, USA
| | - 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 19102, USA
| | - 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 19102, USA
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18
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Dahiya S, Irish BP, Nonnemacher MR, Wigdahl B. Genetic variation and HIV-associated neurologic disease. Adv Virus Res 2013; 87:183-240. [PMID: 23809924 DOI: 10.1016/b978-0-12-407698-3.00006-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
HIV-associated neurologic disease continues to be a significant complication in the era of highly active antiretroviral therapy. A substantial subset of the HIV-infected population shows impaired neuropsychological performance as a result of HIV-mediated neuroinflammation and eventual central nervous system (CNS) injury. CNS compartmentalization of HIV, coupled with the evolution of genetically isolated populations in the CNS, is responsible for poor prognosis in patients with AIDS, warranting further investigation and possible additions to the current therapeutic strategy. This chapter reviews key advances in the field of neuropathogenesis and studies that have highlighted how molecular diversity within the HIV genome may impact HIV-associated neurologic disease. We also discuss the possible functional implications of genetic variation within the viral promoter and possibly other regions of the viral genome, especially in the cells of monocyte-macrophage lineage, which are arguably key cellular players in HIV-associated CNS disease.
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Affiliation(s)
- Satinder Dahiya
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Bryan P Irish
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Miller-Jensen K, Skupsky R, Shah PS, Arkin AP, Schaffer DV. Genetic selection for context-dependent stochastic phenotypes: Sp1 and TATA mutations increase phenotypic noise in HIV-1 gene expression. PLoS Comput Biol 2013; 9:e1003135. [PMID: 23874178 PMCID: PMC3708878 DOI: 10.1371/journal.pcbi.1003135] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/16/2013] [Indexed: 12/13/2022] Open
Abstract
The sequence of a promoter within a genome does not uniquely determine gene expression levels and their variability; rather, promoter sequence can additionally interact with its location in the genome, or genomic context, to shape eukaryotic gene expression. Retroviruses, such as human immunodeficiency virus-1 (HIV), integrate their genomes into those of their host and thereby provide a biomedically-relevant model system to quantitatively explore the relationship between promoter sequence, genomic context, and noise-driven variability on viral gene expression. Using an in vitro model of the HIV Tat-mediated positive-feedback loop, we previously demonstrated that fluctuations in viral Tat-transactivating protein levels generate integration-site-dependent, stochastically-driven phenotypes, in which infected cells randomly ‘switch’ between high and low expressing states in a manner that may be related to viral latency. Here we extended this model and designed a forward genetic screen to systematically identify genetic elements in the HIV LTR promoter that modulate the fraction of genomic integrations that specify ‘Switching’ phenotypes. Our screen identified mutations in core promoter regions, including Sp1 and TATA transcription factor binding sites, which increased the Switching fraction several fold. By integrating single-cell experiments with computational modeling, we further investigated the mechanism of Switching-fraction enhancement for a selected Sp1 mutation. Our experimental observations demonstrated that the Sp1 mutation both impaired Tat-transactivated expression and also altered basal expression in the absence of Tat. Computational analysis demonstrated that the observed change in basal expression could contribute significantly to the observed increase in viral integrations that specify a Switching phenotype, provided that the selected mutation affected Tat-mediated noise amplification differentially across genomic contexts. Our study thus demonstrates a methodology to identify and characterize promoter elements that affect the distribution of stochastic phenotypes over genomic contexts, and advances our understanding of how promoter mutations may control the frequency of latent HIV infection. The sequence of a gene within a cellular genome does not uniquely determine its expression level, even for a single type of cell under fixed conditions. Numerous other factors, including gene location on the chromosome and random gene-expression “noise,” can alter expression patterns and cause differences between otherwise identical cells. This poses new challenges for characterizing the genotype–phenotype relationship. Infection by the human immunodeficiency virus-1 (HIV-1) provides a biomedically important example in which transcriptional noise and viral genomic location impact the decision between viral replication and latency, a quiescent but reversible state that cannot be eliminated by anti-viral therapies. Here, we designed a forward genetic screen to systematically identify mutations in the HIV promoter that alter the fraction of genomic integrations that specify noisy/reactivating expression phenotypes. The mechanisms by which the selected mutations specify the observed phenotypic enrichments are investigated through a combination of single-cell experiments and computational modeling. Our study provides a framework for identifying genetic sequences that alter the distribution of stochastic expression phenotypes over genomic locations and for characterizing their mechanisms of regulation. Our results also may yield further insights into the mechanisms by which HIV sequence evolution can alter the propensity for latent infections.
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Affiliation(s)
- Kathryn Miller-Jensen
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- * E-mail: (KMJ); (DVS)
| | - Ron Skupsky
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - Priya S. Shah
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - Adam P. Arkin
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - David V. Schaffer
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, United States of America
- * E-mail: (KMJ); (DVS)
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20
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Impact of Tat Genetic Variation on HIV-1 Disease. Adv Virol 2012; 2012:123605. [PMID: 22899925 PMCID: PMC3414192 DOI: 10.1155/2012/123605] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) promoter or long-terminal repeat (LTR) regulates viral gene expression by interacting with multiple viral and host factors. The viral transactivator protein Tat plays an important role in transcriptional activation of HIV-1 gene expression. Functional domains of Tat and its interaction with transactivation response element RNA and cellular transcription factors have been examined. Genetic variation within tat of different HIV-1 subtypes has been shown to affect the interaction of the viral transactivator with cellular and/or viral proteins, influencing the overall level of transcriptional activation as well as its action as a neurotoxic protein. Consequently, the genetic variability within tat may impact the molecular architecture of functional domains of the Tat protein that may impact HIV pathogenesis and disease. Tat as a therapeutic target for anti-HIV drugs has also been discussed.
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21
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Li L, Aiamkitsumrit B, Pirrone V, Nonnemacher MR, Wojno A, Passic S, Flaig K, Kilareski E, Blakey B, Ku J, Parikh N, Shah R, Martin-Garcia J, Moldover B, Servance L, Downie D, Lewis S, Jacobson JM, Kolson D, Wigdahl B. Development of co-selected single nucleotide polymorphisms in the viral promoter precedes the onset of human immunodeficiency virus type 1-associated neurocognitive impairment. J Neurovirol 2011; 17:92-109. [PMID: 21225391 PMCID: PMC3057211 DOI: 10.1007/s13365-010-0014-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 11/15/2010] [Accepted: 11/24/2010] [Indexed: 01/03/2023]
Abstract
The long terminal repeat (LTR) regulates gene expression of HIV-1 by interacting with multiple host and viral factors. Cross-sectional studies in the pre-HAART era demonstrated that single nucleotide polymorphisms (SNPs) in peripheral blood-derived LTRs (a C-to-T change at position 3 of C/EBP site I (3T) and at position 5 of Sp site III (5T)) increased in frequency as disease severity increased. Additionally, the 3T variant correlated with HIV-1-associated dementia. LTR sequences derived by longitudinal sampling of peripheral blood from a single patient in the DrexelMed HIV/AIDS Genetic Analysis Cohort resulted in the detection of the 3T and 5T co-selected SNPs before the onset of neurologic impairment, demonstrating that these SNPs may be useful in predicting HIV-associated neurological complications. The relative fitness of the LTRs containing the 3T and/or 5T co-selected SNPs as they evolve in their native patient-derived LTR backbone structure demonstrated a spectrum of basal and Tat-mediated transcriptional activities using the IIIB-derived Tat and colinear Tat derived from the same molecular clone containing the 3T/5T LTR SNP. In silico predictions utilizing colinear envelope sequence suggested that the patient's virus evolved from an X4 to an R5 swarm prior to the development of neurological complications and more advanced HIV disease. These results suggest that the HIV-1 genomic swarm may evolve during the course of disease in response to selective pressures that lead to changes in prevalence of specific polymorphisms in the LTR, env, and/or tat that could predict the onset of neurological disease and result in alterations in viral function.
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Affiliation(s)
- Luna Li
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Benjamas Aiamkitsumrit
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Vanessa Pirrone
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Michael R. Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Adam Wojno
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Shendra Passic
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Katherine Flaig
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Evelyn Kilareski
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brandon Blakey
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jade Ku
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Nirzari Parikh
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Rushabh Shah
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Julio Martin-Garcia
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | | | - Laila Servance
- Division of Infectious Disease and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - David Downie
- Division of Infectious Disease and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Sharon Lewis
- Division of Infectious Disease and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jeffrey M. Jacobson
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA. Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA. Division of Infectious Disease and HIV Medicine, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Dennis Kolson
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, MS #1013A, Philadelphia, PA 19102, USA. Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA. Center for Clinical and Translational Medicine, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
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22
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Liu Y, Nonnemacher MR, Stauff DL, Li L, Banerjee A, Irish B, Kilareski E, Rajagopalan N, Suchitra JB, Khan ZK, Ranga U, Wigdahl B. Structural and functional studies of CCAAT/enhancer binding sites within the human immunodeficiency virus type 1 subtype C LTR. Biomed Pharmacother 2010; 64:672-80. [PMID: 20970301 DOI: 10.1016/j.biopha.2010.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/05/2010] [Indexed: 11/17/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) subtype C, which is most predominant in sub-Saharan Africa as well as in Asia and India, is the most prevalent subtype worldwide. A large number of transcription factor families have been shown to be involved in regulating HIV-1 gene expression in T lymphocytes and cells of the monocyte-macrophage lineage. Among these, proteins of the CCAAT/enhancer binding protein (C/EBP) family are of particular importance in regulating HIV-1 gene expression within cells of the monocytic lineage during the course of hematologic development and cellular activation. Few studies have examined the role of C/EBPs in long terminal repeat (LTR)-directed viral gene expression of HIV-1 subtypes other than subtype B. Within subtype B viruses, two functional C/EBP sites located upstream of the TATA box are required for efficient viral replication in cells of the monocyte-macrophage lineage. We report the identification of three putative subtype C C/EBP sites, upstream site 1 and 2 (C-US1 and C-US2) and downstream site 1 (C-DS1). C-US1 and C-DS1 were shown to form specific DNA-protein complexes with members of the C/EBP family (C/EBPα, β, and δ). Functionally, within the U-937 monocytic cell line, subtype B and C LTRs were shown to be equally responsive to C/EBPβ-2, although the basal activity of subtype C LTRs appeared to be higher. Furthermore, the synergistic interaction between C/EBPβ-2 and Tat with the subtype C LTR was also observed in U-937 cells as previously demonstrated with the subtype B LTR.
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Affiliation(s)
- Yujie Liu
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
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23
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Shah S, Nonnemacher MR, Pirrone V, Wigdahl B. Innate and adaptive factors regulating human immunodeficiency virus type 1 genomic activation. J Neuroimmune Pharmacol 2010; 5:278-93. [PMID: 20387125 DOI: 10.1007/s11481-010-9207-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 03/08/2010] [Indexed: 01/13/2023]
Abstract
Over the past decade, antiretroviral therapy targeting the viral entry process, reverse transcriptase, integrase, and protease, has prolonged the lives of people infected with human immunodeficiency virus type 1 (HIV-1). However, despite the development of more effective therapeutic strategies, reservoirs of viral infection remain. This review discusses molecular mechanisms surrounding the development of latency from the site of integration to pre- and post-integration maintenance of latency, including epigenetic factors. In addition, an overview of innate and adaptive cells important to HIV-1 infection are examined from the viewpoint of cytokines released and cytokines that act on these cells to explore an overall understanding of HIV-1 proviral genome activation. Finally, this review is discussed from the viewpoint of how an understanding of the interplay of all of these factors will help guide the next generation of therapies.
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Affiliation(s)
- Sonia Shah
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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24
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Kilareski EM, Shah S, Nonnemacher MR, Wigdahl B. Regulation of HIV-1 transcription in cells of the monocyte-macrophage lineage. Retrovirology 2009; 6:118. [PMID: 20030845 PMCID: PMC2805609 DOI: 10.1186/1742-4690-6-118] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 12/23/2009] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has been shown to replicate productively in cells of the monocyte-macrophage lineage, although replication occurs to a lesser extent than in infected T cells. As cells of the monocyte-macrophage lineage become differentiated and activated and subsequently travel to a variety of end organs, they become a source of infectious virus and secreted viral proteins and cellular products that likely initiate pathological consequences in a number of organ systems. During this process, alterations in a number of signaling pathways, including the level and functional properties of many cellular transcription factors, alter the course of HIV-1 long terminal repeat (LTR)-directed gene expression. This process ultimately results in events that contribute to the pathogenesis of HIV-1 infection. First, increased transcription leads to the upregulation of infectious virus production, and the increased production of viral proteins (gp120, Tat, Nef, and Vpr), which have additional activities as extracellular proteins. Increased viral production and the presence of toxic proteins lead to enhanced deregulation of cellular functions increasing the production of toxic cellular proteins and metabolites and the resulting organ-specific pathologic consequences such as neuroAIDS. This article reviews the structural and functional features of the cis-acting elements upstream and downstream of the transcriptional start site in the retroviral LTR. It also includes a discussion of the regulation of the retroviral LTR in the monocyte-macrophage lineage during virus infection of the bone marrow, the peripheral blood, the lymphoid tissues, and end organs such as the brain. The impact of genetic variation on LTR-directed transcription during the course of retrovirus disease is also reviewed.
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Affiliation(s)
- Evelyn M Kilareski
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Sonia Shah
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Michael R Nonnemacher
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Brian Wigdahl
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
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25
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Abstract
Since identification of the human immunodeficiency virus-1 (HIV-1), numerous studies suggest a link between neurological impairments, in particular dementia, with acquired immunodeficiency syndrome (AIDS) with alarming occurrence worldwide. Approximately, 60% of HIV-infected people show some form of neurological impairment, and neuropathological changes are found in 90% of autopsied cases. Approximately 30% of untreated HIV-infected persons may develop dementia. The mechanisms behind these pathological changes are still not understood. Mounting data obtained by in vivo and in vitro experiments suggest that neuronal apoptosis is a major feature of HIV associated dementia (HAD), which can occur in the absence of direct infection of neurons. The major pathway of neuronal apoptosis occurs indirectly through release of neurotoxins by activated cells in the central nervous system (CNS) involving the induction of excitotoxicity and oxidative stress. In addition a direct mechanism induced by viral proteins in the pathogenesis of HAD may also play a role. This review focuses on the molecular mechanisms of HIV-associated dementia and possible therapeutic strategies.
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Affiliation(s)
- Hakan Ozdener
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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