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Zhou Z, Jiang Y, Zhong X, Yang J, Yang G. Characteristics and mechanisms of latency-reversing agents in the activation of the human immunodeficiency virus 1 reservoir. Arch Virol 2023; 168:301. [PMID: 38019293 DOI: 10.1007/s00705-023-05931-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/23/2023] [Indexed: 11/30/2023]
Abstract
The "Shock and Kill" method is being considered as a potential treatment for eradicating HIV-1 and achieving a functional cure for acquired immunodeficiency syndrome (AIDS). This approach involves using latency-reversing agents (LRAs) to activate human immunodeficiency virus (HIV-1) transcription in latent cells, followed by treatment with antiviral drugs to kill these cells. Although LRAs have shown promise in HIV-1 patient research, their widespread clinical use is hindered by side effects and limitations. In this review, we categorize and explain the mechanisms of these agonists in activating HIV-1 in vivo and discuss their advantages and disadvantages. In the future, combining different HIV-1 LRAs may overcome their respective shortcomings and facilitate a functional cure for HIV-1.
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Affiliation(s)
- Zhujiao Zhou
- Department of Clinical Medicine, School of Medicine, Hangzhou City University, Hangzhou, China
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, 310013, China
| | - Yashuang Jiang
- Department of Clinical Medicine, School of Medicine, Hangzhou City University, Hangzhou, China
| | - Xinyu Zhong
- Department of Clinical Medicine, School of Medicine, Hangzhou City University, Hangzhou, China
- College of Pharmacy, Zhejiang University of Technology, Hangzhou, 310013, China
| | - Jingyi Yang
- Department of Clinical Medicine, School of Medicine, Hangzhou City University, Hangzhou, China
| | - Geng Yang
- Department of Clinical Medicine, School of Medicine, Hangzhou City University, Hangzhou, China.
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310013, China.
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2
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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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3
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Zhao JY, Osipovich O, Koues OI, Majumder K, Oltz EM. Activation of Mouse Tcrb: Uncoupling RUNX1 Function from Its Cooperative Binding with ETS1. THE JOURNAL OF IMMUNOLOGY 2017. [PMID: 28637900 DOI: 10.4049/jimmunol.1700146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
T lineage commitment requires the coordination of key transcription factors (TFs) in multipotent progenitors that transition them away from other lineages and cement T cell identity. Two important TFs for the multipotent progenitors to T lineage transition are RUNX1 and ETS1, which bind cooperatively to composite sites throughout the genome, especially in regulatory elements for genes involved in T lymphopoiesis. Activation of the TCR β (Tcrb) locus in committed thymocytes is a critical process for continued development of these cells, and is mediated by an enhancer, Eβ, which harbors two RUNX-ETS composite sites. An outstanding issue in understanding T cell gene expression programs is whether RUNX1 and ETS1 have independent functions in enhancer activation that can be dissected from cooperative binding. We now show that RUNX1 is sufficient to activate the endogenous mouse Eβ element and its neighboring 25 kb region by independently tethering this TF without coincidental ETS1 binding. Moreover, RUNX1 is sufficient for long-range promoter-Eβ looping, nucleosome clearance, and robust transcription throughout the Tcrb recombination center, spanning both DβJβ clusters. We also find that a RUNX1 domain, termed the negative regulatory domain for DNA binding, can compensate for the loss of ETS1 binding at adjacent sites. Thus, we have defined independent roles for RUNX1 in the activation of a T cell developmental enhancer, as well as its ability to mediate specific changes in chromatin landscapes that accompany long-range induction of recombination center promoters.
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Affiliation(s)
- Jiang-Yang Zhao
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Oleg Osipovich
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Olivia I Koues
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Kinjal Majumder
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
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Raiten DJ, Sakr Ashour FA, Ross AC, Meydani SN, Dawson HD, Stephensen CB, Brabin BJ, Suchdev PS, van Ommen B. Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE). J Nutr 2015; 145:1039S-1108S. [PMID: 25833893 PMCID: PMC4448820 DOI: 10.3945/jn.114.194571] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/08/2014] [Accepted: 10/29/2014] [Indexed: 02/06/2023] Open
Abstract
An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.
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Affiliation(s)
- Daniel J Raiten
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD;
| | - Fayrouz A Sakr Ashour
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD
| | - A Catharine Ross
- Departments of Nutritional Sciences and Veterinary and Biomedical Science and Center for Molecular Immunology and Infectious Disease, Pennsylvania State University, University Park, PA
| | - Simin N Meydani
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA
| | - Harry D Dawson
- USDA-Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics, and Immunology Laboratory, Beltsville, MD
| | - Charles B Stephensen
- Agricultural Research Service, Western Human Nutrition Research Center, USDA, Davis, CA
| | - Bernard J Brabin
- Child and Reproductive Health Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Global Child Health Group, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Parminder S Suchdev
- Department of Pediatrics and Global Health, Emory University, Atlanta, GA; and
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5
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Murry JP, Godoy J, Mukim A, Swann J, Bruce JW, Ahlquist P, Bosque A, Planelles V, Spina CA, Young JAT. Sulfonation pathway inhibitors block reactivation of latent HIV-1. Virology 2014; 471-473:1-12. [PMID: 25310595 DOI: 10.1016/j.virol.2014.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 06/16/2014] [Accepted: 08/18/2014] [Indexed: 12/12/2022]
Abstract
Long-lived pools of latently infected cells are a significant barrier to the development of a cure for HIV-1 infection. A better understanding of the mechanisms of reactivation from latency is needed to facilitate the development of novel therapies that address this problem. Here we show that chemical inhibitors of the sulfonation pathway prevent virus reactivation, both in latently infected J-Lat and U1 cell lines and in a primary human CD4+ T cell model of latency. In each of these models, sulfonation inhibitors decreased transcription initiation from the HIV-1 promoter. These inhibitors block transcription initiation at a step that lies downstream of nucleosome remodeling and affects RNA polymerase II recruitment to the viral promoter. These results suggest that the sulfonation pathway acts by a novel mechanism to regulate efficient virus transcription initiation during reactivation from latency, and further that augmentation of this pathway could be therapeutically useful.
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Affiliation(s)
- Jeffrey P Murry
- Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Joseph Godoy
- Veterans Affairs San Diego Healthcare System, San Diego, CA, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Amey Mukim
- Veterans Affairs San Diego Healthcare System, San Diego, CA, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Justine Swann
- Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - James W Bruce
- Morgridge Institute for Research, Madison, WI, USA; Institute for Molecular Virology, University of Wisconsin, Madison, WI, USA; McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, WI, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Paul Ahlquist
- Morgridge Institute for Research, Madison, WI, USA; Institute for Molecular Virology, University of Wisconsin, Madison, WI, USA; McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, WI, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Alberto Bosque
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Vicente Planelles
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Celsa A Spina
- Veterans Affairs San Diego Healthcare System, San Diego, CA, USA; Department of Pathology, University of California, San Diego, La Jolla, CA, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - John A T Young
- Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037, USA; Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA.
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Kamiyama H, Kakoki K, Shigematsu S, Izumida M, Yashima Y, Tanaka Y, Hayashi H, Matsuyama T, Sato H, Yamamoto N, Sano T, Shidoji Y, Kubo Y. CXCR4-tropic, but not CCR5-tropic, human immunodeficiency virus infection is inhibited by the lipid raft-associated factors, acyclic retinoid analogs, and cholera toxin B subunit. AIDS Res Hum Retroviruses 2013; 29:279-88. [PMID: 22845664 DOI: 10.1089/aid.2012.0174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Development of an effective low-cost anti-acquired immunodeficiency syndrome (AIDS) drugs is needed for treatment of AIDS patients in developing countries. Host cell lipid raft microdomains, which are enriched with cholesterol, glycolipids, ceramide, and gangliosides, are important for human immunodeficiency virus type 1 (HIV-1) entry. Retinoid analogs have been shown to modulate ceramide levels in the cell membrane, while cholera toxin B subunit (CT-B) specifically binds to the ganglioside GM1. In this study, we found that the acyclic retinoid analogs geranylgeranoic acid (GGA) and NIK-333 as well as CT-B efficiently attenuate CXCR4-tropic, but not CCR5-tropic, HIV-1 vector infection. We also found that GGA and NIK-333 suppress CXCR4-tropic HIV-1 infection by attenuating CXCR4 expression. CT-B also attenuated CXCR4-tropic HIV-1 infection, but did not suppress CXCR4 expression. These results suggest a distinct role for lipid raft microdomains in CXCR4- and CCR5-tropic HIV-1 infections and illuminate novel agents for the development of AIDS therapy.
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Affiliation(s)
- Haruka Kamiyama
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Department of Molecular and Cellular Biology, Graduate School of Human Health Sciences, University of Nagasaki, Nagasaki, Japan
| | - Katsura Kakoki
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
| | - Sayuri Shigematsu
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Mai Izumida
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yuka Yashima
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yuetsu Tanaka
- Department of Immunology, Graduate School and Faculty of Medicine, University of the Ryukyu, Okinawa, Japan
| | - Hideki Hayashi
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Toshifumi Matsuyama
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Hironori Sato
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Naoki Yamamoto
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Department of Microbiology, National University of Singapore, Singapore, Singapore
| | | | - Yoshihiro Shidoji
- Department of Molecular and Cellular Biology, Graduate School of Human Health Sciences, University of Nagasaki, Nagasaki, Japan
| | - Yoshinao Kubo
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
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7
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Ying H, Zhang Y, Zhou X, Qu X, Wang P, Liu S, Lu D, Zhu H. Selective histonedeacetylase inhibitor M344 intervenes in HIV-1 latency through increasing histone acetylation and activation of NF-kappaB. PLoS One 2012; 7:e48832. [PMID: 23166597 PMCID: PMC3499534 DOI: 10.1371/journal.pone.0048832] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 10/05/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Histone deacetylase (HDAC) inhibitors present an exciting new approach to activate HIV production from latently infected cells to potentially enhance elimination of these cells and achieve a cure. M344, a novel HDAC inhibitor, shows robust activity in a variety of cancer cells and relatively low toxicity compared to trichostatin A (TSA). However, little is known about the effects and action mechanism of M344 in inducing HIV expression in latently infected cells. METHODOLOGY/PRINCIPAL FINDINGS Using the Jurkat T cell model of HIV latency, we demonstrate that M344 effectively reactivates HIV-1 gene expression in latently infected cells. Moreover, M344-mediated activation of the latent HIV LTR can be strongly inhibited by a NF-κB inhibitor aspirin. We further show that M344 acts by increasing the acetylation of histone H3 and histone H4 at the nucleosome 1 (nuc-1) site of the HIV-1 long terminal repeat (LTR) and by inducing NF-κB p65 nuclear translocation and direct RelA DNA binding at the nuc-1 region of the HIV-1 LTR. We also found that M344 synergized with prostratin to activate the HIV-1 LTR promoter in latently infected cells. CONCLUSIONS/SIGNIFICANCE These results suggest the potential of M344 in anti-latency therapies and an important role for histone modifications and NF-κB transcription factors in regulating HIV-1 LTR gene expression.
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Affiliation(s)
- Hao Ying
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Yuhao Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Xin Zhou
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Xiying Qu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Pengfei Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Sijie Liu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Daru Lu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Huanzhang Zhu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
- * E-mail:
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What did we learn on host's genetics by studying large cohorts of HIV-1-infected patients in the genome-wide association era? Curr Opin HIV AIDS 2011; 6:290-6. [PMID: 21546832 DOI: 10.1097/coh.0b013e3283478449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Genome-wide association studies (GWASs) performed in large cohorts of HIV-1-infected patients have shown that high throughput genomics can add valuable information in understanding disease progression. We report recent information gathered in the international field during the last few years and revisit the importance of well documented cohorts for genotype-phenotype association studies. RECENT FINDINGS The majority of GWASs in the HIV-1 field found that viral loads and disease progression are under the control of variants located in the major histocompatibility complex (MHC) in untreated patients. Although these experiments brought a new and more objective vision of genotype-phenotype correlations in HIV-1 disease, they also pointed out that less than 15% of the observed phenotypic variability can be explained as common genetic variants. Most of the studies have included mainly white patients and the few studies performed in Africans are underpowered but suggest that MHC is probably not the only genetic determinant influencing disease progression in this population. SUMMARY Although the first results of the GWASs in HIV disease look as a confirmation of previous findings, high throughput agnostic genomics entered the field of chronic infectious diseases and will probably unveil new genotype-phenotype associations in the future. Networks between existing cohorts leading to 'virtual mega-cohorts' will be necessary to increase the probability to discover new genetic pathways important for HIV disease. Finally, predictive models including genetic information for clinical usage is another challenge in HIV disease genetics.
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Nuclear receptor signaling inhibits HIV-1 replication in macrophages through multiple trans-repression mechanisms. J Virol 2011; 85:10834-50. [PMID: 21849441 DOI: 10.1128/jvi.00789-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Sexually transmitted pathogens activate HIV-1 replication and inflammatory gene expression in macrophages through engagement of Toll-like receptors (TLRs). Ligand-activated nuclear receptor (NR) transcription factors, including glucocorticoid receptor (GR), peroxisome proliferator-activated receptor gamma (PPARγ), and liver X receptor (LXR), are potent inhibitors of TLR-induced inflammatory gene expression. We therefore hypothesized that ligand-activated NRs repress both basal and pathogen-enhanced HIV-1 replication in macrophages by directly repressing HIV-1 transcription and by ameliorating the local proinflammatory response to pathogens. We show that the TLR2 ligand PAM3CSK4 activated virus transcription in macrophages and that NR signaling repressed both basal and TLR-induced HIV-1 transcription. NR ligand treatment repressed HIV-1 expression when added concurrently with TLR ligands and in the presence of cycloheximide, demonstrating that they act independently of new cellular gene expression. We found that treatment with NR ligands inhibited the association of AP-1 and NF-κB subunits, as well as the coactivator CBP, with the long terminal repeat (LTR). We show for the first time that the nuclear corepressor NCoR is bound to HIV-1 LTR in unstimulated macrophages and is released from the LTR after TLR engagement. Treatment with PPARγ and LXR ligands, but not GR ligands, prevented this TLR-induced clearance of NCoR from the LTR. Our data demonstrate that both classical and nonclassical trans-repression mechanisms account for NR-mediated HIV-1 repression. Finally, NR ligand treatment inhibited the potent proinflammatory response induced by PAM3CSK4 that would otherwise activate HIV-1 expression in infected cells. Our findings provide a rationale for studying ligand-activated NRs as modulators of basal and inflammation-induced HIV-1 replication.
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10
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Gautier VW, Gu L, O'Donoghue N, Pennington S, Sheehy N, Hall WW. In vitro nuclear interactome of the HIV-1 Tat protein. Retrovirology 2009; 6:47. [PMID: 19454010 PMCID: PMC2702331 DOI: 10.1186/1742-4690-6-47] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 05/19/2009] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND One facet of the complexity underlying the biology of HIV-1 resides not only in its limited number of viral proteins, but in the extensive repertoire of cellular proteins they interact with and their higher-order assembly. HIV-1 encodes the regulatory protein Tat (86-101aa), which is essential for HIV-1 replication and primarily orchestrates HIV-1 provirus transcriptional regulation. Previous studies have demonstrated that Tat function is highly dependent on specific interactions with a range of cellular proteins. However they can only partially account for the intricate molecular mechanisms underlying the dynamics of proviral gene expression. To obtain a comprehensive nuclear interaction map of Tat in T-cells, we have designed a proteomic strategy based on affinity chromatography coupled with mass spectrometry. RESULTS Our approach resulted in the identification of a total of 183 candidates as Tat nuclear partners, 90% of which have not been previously characterised. Subsequently we applied in silico analysis, to validate and characterise our dataset which revealed that the Tat nuclear interactome exhibits unique signature(s). First, motif composition analysis highlighted that our dataset is enriched for domains mediating protein, RNA and DNA interactions, and helicase and ATPase activities. Secondly, functional classification and network reconstruction clearly depicted Tat as a polyvalent protein adaptor and positioned Tat at the nexus of a densely interconnected interaction network involved in a range of biological processes which included gene expression regulation, RNA biogenesis, chromatin structure, chromosome organisation, DNA replication and nuclear architecture. CONCLUSION We have completed the in vitro Tat nuclear interactome and have highlighted its modular network properties and particularly those involved in the coordination of gene expression by Tat. Ultimately, the highly specialised set of molecular interactions identified will provide a framework to further advance our understanding of the mechanisms of HIV-1 proviral gene silencing and activation.
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Affiliation(s)
- Virginie W Gautier
- UCD-Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
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11
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Abstract
Cellular defence mechanisms against HIV contribute to its persistence. One of the cellular defenses against virus infection is the silencing of viral gene expression. There is evidence that at least two gene-silencing mechanisms are used against the human immuno-deficiency virus (HIV). Paradoxically, this cellular defense mechanism contributes to viral latency and persistence, and we review here the relationship of viral latency to gene-silencing mechanisms.
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Affiliation(s)
- Hoi-Ping Mok
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK
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12
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Rodeheffer C, von Messling V, Milot S, Lepine F, Manges AR, Ward BJ. Disease manifestations of canine distemper virus infection in ferrets are modulated by vitamin A status. J Nutr 2007; 137:1916-22. [PMID: 17634264 DOI: 10.1093/jn/137.8.1916] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The measles virus (MV) causes half a million childhood deaths annually. Vitamin A supplements significantly reduce measles-associated mortality and morbidity. The mechanisms whereby vitamin A acts against MV are not understood and currently there is no satisfactory small animal model for MV infection. We report on the development of a ferret model to study antiviral activity of vitamin A against canine distemper virus (CDV). CDV is closely related to MV at the molecular level and distemper in ferrets mimics measles in humans. We infected vitamin A-replete (control) and vitamin A-depleted ferrets with CDV and assessed the ability of high-dose vitamin A supplements to influence CDV disease. In control ferrets, CDV infection caused fever, rash, conjunctivitis, cough, coryza, and diarrhea. In contrast, control ferrets that were given 30 mg of vitamin A did not develop typical distemper after infection and exhibited only a mild rash. The supplement did not negatively affect ferret health and resulted in a 100% increase in serum and liver vitamin A concentrations. We also found that profound vitamin A deficiency is inducible in ferrets and can be rapidly reversed upon high-dose vitamin A supplementation. Vitamin A deficiency caused anorexia, diarrhea, cataracts, behavioral abnormalities, and ultimately death, with or without CDV infection. All ferrets that received vitamin A supplements, however, recovered uneventfully from CDV infection. These results replicate many aspects of the observations of vitamin A therapy in humans with measles and suggest that CDV infection in ferrets is an appropriate model for the study of the antiviral mechanism of vitamin A.
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Affiliation(s)
- Carey Rodeheffer
- McGill University Health Centre Research Institute, Faculty of Medicine, Division of Infectious Diseases, Montreal General Hospital, Montreal, QC, Canada
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Stevens M, De Clercq E, Balzarini J. The regulation of HIV-1 transcription: molecular targets for chemotherapeutic intervention. Med Res Rev 2006; 26:595-625. [PMID: 16838299 PMCID: PMC7168390 DOI: 10.1002/med.20081] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The regulation of transcription of the human immunodeficiency virus (HIV) is a complex event that requires the cooperative action of both viral and cellular components. In latently infected resting CD4(+) T cells HIV-1 transcription seems to be repressed by deacetylation events mediated by histone deacetylases (HDACs). Upon reactivation of HIV-1 from latency, HDACs are displaced in response to the recruitment of histone acetyltransferases (HATs) by NF-kappaB or the viral transcriptional activator Tat and result in multiple acetylation events. Following chromatin remodeling of the viral promoter region, transcription is initiated and leads to the formation of the TAR element. The complex of Tat with p-TEFb then binds the loop structures of TAR RNA thereby positioning CDK9 to phosphorylate the cellular RNA polymerase II. The Tat-TAR-dependent phosphorylation of RNA polymerase II plays an important role in transcriptional elongation as well as in other post-transcriptional events. As such, targeting of Tat protein (and/or cellular cofactors) provide an interesting perspective for therapeutic intervention in the HIV replicative cycle and may afford lifetime control of the HIV infection.
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Affiliation(s)
- Miguel Stevens
- Rega Institute for Medical Research, Minderbroedersstraat 10, B‐3000 Leuven, Belgium
| | - Erik De Clercq
- Rega Institute for Medical Research, Minderbroedersstraat 10, B‐3000 Leuven, Belgium
| | - Jan Balzarini
- Rega Institute for Medical Research, Minderbroedersstraat 10, B‐3000 Leuven, Belgium
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Andollo N, Boyano MD, Andrade R, Aréchaga JM. Epigenetic regulation of the imprinted U2af1-rs1 gene during retinoic acid-induced differentiation of embryonic stem cells. Dev Growth Differ 2006; 48:349-60. [PMID: 16872448 DOI: 10.1111/j.1440-169x.2006.00873.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epigenetic modifications such as DNA methylation and changes in chromatin structure are changes in the chemical composition or structure of DNA that work by regulating gene expression. Their mechanisms of action have been generally studied in imprinted genes. The present work analyzes the involvement of these mechanisms in the expression of the U2af1-rs1 imprinted gene during the differentiation process of embryonic stem (ES) cells induced by retinoic acid. By DNA digestion with methylation-dependent or independent restriction enzymes and consecutive Southern blot, we have found that methylation of the U2af1-rs1 gene increases in differentiated ES cells and in embryoid bodies. However, northern blot and real-time reverse transcription-polymerase chain reaction analysis showed a higher expression of the U2af1-rs1 gene in differentiated ES cells and in embryoid bodies than in undifferentiated ones. On the other hand, the sensitivity to DNase-I assay demonstrated an open chromatin conformation for differentiated cells with regard to undifferentiated ES cells. Our results suggest that the expression of the U2af1-rs1 gene would be regulated by changes in chromatin structure rather than by DNA methylation during the RA-induced process of differentiation of ES cells.
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Affiliation(s)
- Noelia Andollo
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Vizcaya, Spain
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Brady J, Kashanchi F. Tat gets the "green" light on transcription initiation. Retrovirology 2005; 2:69. [PMID: 16280076 PMCID: PMC1308864 DOI: 10.1186/1742-4690-2-69] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 11/09/2005] [Indexed: 11/10/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat transactivation is an essential step in the viral life cycle. Over the past several years, it has become widely accepted that Tat exerts its transcriptional effect by binding the transactivation-responsive region (TAR) and enhancing transcriptional elongation. Consistent with this hypothesis, it has been shown that Tat promotes the binding of P-TEFb, a transcription elongation factor composed of cyclin T1 and cdk9, and the interaction of Tat with P-TEFb and TAR leads to hyperphosphorylation of the C-terminal domain (CTD) of RNA Pol II and increased processivity of RNA Pol II. A recent report, however, has generated renewed interest that Tat may also play a critical role in transcription complex (TC) assembly at the preinitiation step. Using in vivo chromatin immunoprecipitation assays, the authors reported that the HIV TC contains TBP but not TBP-associated factors. The stimulatory effect involved the direct interaction of Tat and P-TEFb and was evident at the earliest step of TC assembly, the TBP-TATA box interaction. In this article, we will review this data in context of earlier data which also support Tat's involvement in transcriptional complex assembly. Specifically, we will discuss experiments which demonstrated that Tat interacted with TBP and increased transcription initiation complex stability in cell free assays. We will also discuss studies which demonstrated that over expression of TBP alone was sufficient to obtain Tat activated transcription in vitro and in vivo. Finally, studies using self-cleaving ribozymes which suggested that Tat transactivation was not compatible with pausing of the RNA Pol II at the TAR site will be discussed.
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Affiliation(s)
- John Brady
- National Cancer Institute, Laboratory of Cellular Oncology, Bethesda, MD 20892, USA
| | - Fatah Kashanchi
- The George Washington University School of Medicine, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
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