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Dias J, Cattin A, Bendoumou M, Dutilleul A, Lodge R, Goulet JP, Fert A, Raymond Marchand L, Wiche Salinas TR, Ngassaki Yoka CD, Gabriel EM, Caballero RE, Routy JP, Cohen ÉA, Van Lint C, Ancuta P. Retinoic acid enhances HIV-1 reverse transcription and transcription in macrophages via mTOR-modulated mechanisms. Cell Rep 2024; 43:114414. [PMID: 38943643 PMCID: PMC11341200 DOI: 10.1016/j.celrep.2024.114414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 05/14/2024] [Accepted: 06/12/2024] [Indexed: 07/01/2024] Open
Abstract
The intestinal environment facilitates HIV-1 infection via mechanisms involving the gut-homing vitamin A-derived retinoic acid (RA), which transcriptionally reprograms CD4+ T cells for increased HIV-1 replication/outgrowth. Consistently, colon-infiltrating CD4+ T cells carry replication-competent viral reservoirs in people with HIV-1 (PWH) receiving antiretroviral therapy (ART). Intriguingly, integrative infection in colon macrophages, a pool replenished by monocytes, represents a rare event in ART-treated PWH, thus questioning the effect of RA on macrophages. Here, we demonstrate that RA enhances R5 but not X4 HIV-1 replication in monocyte-derived macrophages (MDMs). RNA sequencing, gene set variation analysis, and HIV interactor NCBI database interrogation reveal RA-mediated transcriptional reprogramming associated with metabolic/inflammatory processes and HIV-1 resistance/dependency factors. Functional validations uncover post-entry mechanisms of RA action including SAMHD1-modulated reverse transcription and CDK9/RNA polymerase II (RNAPII)-dependent transcription under the control of mammalian target of rapamycin (mTOR). These results support a model in which macrophages residing in the intestine of ART-untreated PWH contribute to viral replication/dissemination in an mTOR-sensitive manner.
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Affiliation(s)
- Jonathan Dias
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Amélie Cattin
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Maryam Bendoumou
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université libre de Bruxelles (ULB), 6041 Gosselies, Belgium
| | - Antoine Dutilleul
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université libre de Bruxelles (ULB), 6041 Gosselies, Belgium
| | - Robert Lodge
- Institut de recherches cliniques de Montréal, Montréal, QC, Canada
| | | | - Augustine Fert
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Laurence Raymond Marchand
- Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Tomas Raul Wiche Salinas
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Christ-Dominique Ngassaki Yoka
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Etiene Moreira Gabriel
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada
| | - Ramon Edwin Caballero
- Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada; Department of Microbiology and Immunology, McGill University Health Centre, Montréal, QC, Canada
| | - Jean-Pierre Routy
- Infectious Diseases and Immunity in Global Health Program, Research Institute, McGill University Health Centre, Montréal, QC, Canada; Chronic Viral Illness Service, McGill University Health Centre, Montréal, QC, Canada; Division of Hematology, McGill University Health Centre, Montreal, QC, Canada
| | - Éric A Cohen
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Institut de recherches cliniques de Montréal, Montréal, QC, Canada
| | - Carine Van Lint
- Service of Molecular Virology, Department of Molecular Biology (DBM), Université libre de Bruxelles (ULB), 6041 Gosselies, Belgium.
| | - Petronela Ancuta
- Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada; Centre de recherche du centre hospitalier de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada.
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Olwenyi OA, Acharya A, Routhu NK, Pierzchalski K, Jones JW, Kane MA, Sidell N, Mohan M, Byrareddy SN. Retinoic Acid Improves the Recovery of Replication-Competent Virus from Latent SIV Infected Cells. Cells 2020; 9:E2076. [PMID: 32932813 PMCID: PMC7565696 DOI: 10.3390/cells9092076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/31/2022] Open
Abstract
The accurate estimation and eradication of Human Immunodeficiency Virus (HIV) viral reservoirs is limited by the incomplete reactivation of cells harboring the latent replication-competent virus. We investigated whether the in vitro and in vivo addition of retinoic acid (RA) enhances virus replication and improves the detection of latent virus. Peripheral blood mononuclear cells (PBMCs) from naive and anti-retroviral therapy (ART)-treated SIV-infected rhesus macaques (RMs) were cultured in vitro with anti-CD3/CD28 + IL-2 in the presence/absence of RA. Viral RNA and p27 levels were quantified using RT-qPCR and ELISA, respectively. Viral reservoirs were estimated using the Tat/Rev-Induced Limited Dilution Assay (TILDA) and Quantitative Viral Outgrowth Assay (QVOA). In vitro and in vivo measures revealed that there was also an increase in viral replication in RA-treated versus without RA conditions. In parallel, the addition of RA to either CD3/CD28 or phorbol myristate acetate (PMA)/ionomycin during QVOA and TILDA, respectively, was shown to augment reactivation of the replication-competent viral reservoir in anti-retroviral therapy (ART)-suppressed RMs as shown by a greater than 2.3-fold increase for QVOA and 1 to 2-fold increments for multi-spliced RNA per million CD4+ T cells. The use of RA can be a useful approach to enhance the efficiency of current protocols used for in vitro and potentially in vivo estimates of CD4+ T cell latent reservoirs. In addition, flow cytometry analysis revealed that RA improved estimates of various viral reservoir assays by eliciting broad CD4 T-cell activation as demonstrated by elevated CD25 and CD38 but reduced CD69 and PD-1 expressing cells.
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Affiliation(s)
- Omalla A. Olwenyi
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA; (O.A.O.); (A.A.); (N.K.R.)
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
| | - Arpan Acharya
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA; (O.A.O.); (A.A.); (N.K.R.)
| | - Nanda Kishore Routhu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA; (O.A.O.); (A.A.); (N.K.R.)
| | - Keely Pierzchalski
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA; (K.P.); (J.W.J.); (M.A.K.)
| | - Jace W. Jones
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA; (K.P.); (J.W.J.); (M.A.K.)
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA; (K.P.); (J.W.J.); (M.A.K.)
| | - Neil Sidell
- Department of Obstetrics and Gynecology, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Mahesh Mohan
- Texas Biomedical Research Institute, Southwest National Primate Research Institute, San Antonio, TX 78227, USA;
| | - Siddappa N. Byrareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA; (O.A.O.); (A.A.); (N.K.R.)
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
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3
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Zhang Y, Planas D, Raymond Marchand L, Massanella M, Chen H, Wacleche VS, Gosselin A, Goulet JP, Filion M, Routy JP, Chomont N, Ancuta P. Improving HIV Outgrowth by Optimizing Cell-Culture Conditions and Supplementing With all-trans Retinoic Acid. Front Microbiol 2020; 11:902. [PMID: 32499767 PMCID: PMC7243435 DOI: 10.3389/fmicb.2020.00902] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 04/16/2020] [Indexed: 01/25/2023] Open
Abstract
The persistence of replication-competent HIV reservoirs in people living with HIV (PLWH) receiving antiretroviral therapy (ART) is a barrier to cure. Therefore, their accurate quantification is essential for evaluating the efficacy of new therapeutic interventions and orienting the decision to interrupt ART. Quantitative viral outgrowth assays (QVOAs) represent the "gold standard" for measuring the size of replication-competent HIV reservoirs. However, they require large numbers of cells and are technically challenging. This justifies the need for the development of novel simplified methods adapted for small biological samples. Herein, we sought to simplify the viral outgrowth procedure (VOP) by (i) using memory CD4+ T-cells, documented to be enriched in HIV reservoirs (ii) optimizing cell-culture conditions, and (iii) supplementing with all-trans retinoic acid (ATRA), a positive regulator of HIV replication. Memory CD4+ T-cells were sorted from the peripheral blood of ART-treated (HIV+ART; n = 14) and untreated (HIV+; n = 5) PLWH. The VOP was first performed with one original replicate of 1 × 106 cells/well in 48-well plates. Cells were stimulated via CD3/CD28 for 3 days, washed to remove residual CD3/CD28 Abs, split every 3 days for optimal cell density, and cultured in the presence or the absence of ATRA for 12 days. Soluble and intracellular HIV-p24 levels were quantified by ELISA and flow cytometry, respectively. Optimal cell-culture density achieved by splitting improved HIV outgrowth detection. ATRA promoted superior/accelerated detection of replication-competent HIV in all HIV+ART individuals tested, including those with low/undetectable viral outgrowth in the absence of ATRA. Finally, this VOP was used to design a simplified ATRA-based QVOA by including 4 and 6 original replicates of 1 × 106 cells/well in 48-well plates and 2 × 105 cells/well in 96-well plates, respectively. Consistently, the number of infectious units per million cells (IUPM) was significantly increased in the presence of ATRA. In conclusion, we demonstrate that memory CD4+ T-cell splitting for optimal density in culture and ATRA supplementation significantly improved the efficacy of HIV outgrowth in a simplified ATRA-based QVOA performed in the absence of feeder/target cells or indicator cell lines.
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Affiliation(s)
- Yuwei Zhang
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | - Delphine Planas
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | | | - Marta Massanella
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | - Huicheng Chen
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | - Vanessa Sue Wacleche
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | - Annie Gosselin
- Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | | | | | | | - Nicolas Chomont
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
| | - Petronela Ancuta
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada.,Centre hospitalier de l'Université de Montréal (CHUM)-Research Centre, Montreal, QC, Canada
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4
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Gosselin A, Wiche Salinas TR, Planas D, Wacleche VS, Zhang Y, Fromentin R, Chomont N, Cohen ÉA, Shacklett B, Mehraj V, Ghali MP, Routy JP, Ancuta P. HIV persists in CCR6+CD4+ T cells from colon and blood during antiretroviral therapy. AIDS 2017; 31:35-48. [PMID: 27835617 PMCID: PMC5131694 DOI: 10.1097/qad.0000000000001309] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/07/2016] [Accepted: 10/18/2016] [Indexed: 12/19/2022]
Abstract
OBJECTIVES The objective of this article is to investigate the contribution of colon and blood CD4 T-cell subsets expressing the chemokine receptor CCR6 to HIV persistence during antiretroviral therapy. DESIGN Matched sigmoid biopsies and blood samples (n = 13) as well as leukapheresis (n = 20) were collected from chronically HIV-infected individuals receiving antiretroviral therapy. Subsets of CD4 T cells with distinct differentiation/polarization profiles were identified using surface markers as follows: memory (TM, CD45RA), central memory (TCM; CD45RACCR7), effector (TEM/TM; CD45RACCR7), Th17 (CCR6CCR4), Th1Th17 (CCR6CXCR3), Th1 (CCR6CXCR3), and Th2 (CCR6CCR4). METHODS We used polychromatic flow cytometry for cell sorting, nested real-time PCR for HIV DNA quantification, ELISA and flow cytometry for HIV p24 quantification. HIV reactivation was induced by TCR triggering in the presence/absence of all-trans retinoic acid. RESULTS Compared with blood, the frequency of CCR6 TM was higher in the colon. In both colon and blood compartments, CCR6 TM were significantly enriched in HIV DNA when compared with their CCR6 counterparts (n = 13). In blood, integrated HIV DNA levels were significantly enriched in CCR6 versus CCR6 TCM of four of five individuals and CCR6 versus CCR6 TEM of three of five individuals. Among blood TCM, Th17 and Th1Th17 contributed the most to the pool of cells harboring integrated HIV DNA despite their reduced frequency compared with Th2, which were infected the least. HIV reactivation was induced by TCR triggering and/or retinoic acid exposure at higher levels in CCR6 versus CCR6 TM, TCM, and TEM. CONCLUSION CCR6 is a marker for colon and blood CD4 T cells enriched for replication-competent HIV DNA. Novel eradication strategies should target HIV persistence in CCR6CD4 T cells from various anatomic sites.
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Affiliation(s)
| | - Tomas Raul Wiche Salinas
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
| | - Delphine Planas
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
| | - Vanessa S. Wacleche
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
| | - Yuwei Zhang
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
| | | | - Nicolas Chomont
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
| | - Éric A. Cohen
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
- Institut de Recherche Clinique de Montréal, Montréal, Québec, Canada
| | | | - Vikram Mehraj
- Chronic Viral Illness Service and Research Institute
| | | | - Jean-Pierre Routy
- Chronic Viral Illness Service and Research Institute
- Division of Hematology, McGill University Health Centre, Montreal, Québec, Canada
| | - Petronela Ancuta
- CHUM-Research Centre
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal
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Abstract
A strong causal association has become evident between Zika virus (ZIKV) infection during pregnancy and the occurrence of fetal growth restriction, microcephaly and eye defects. Circumstantial evidence is presented in this paper in support of the hypothesis that these effects, as well as the Guillain-Barré syndrome, are due to an endogenous form of hypervitaminosis A resulting from ZIKV infection-induced damage to the liver and the spillage of stored vitamin A compounds ("retinoids") into the maternal and fetal circulation in toxic concentrations. Retinoids are mainly stored in the liver (about 80%) and are essential for numerous biological functions. In higher concentration, retinoids are potentially cytotoxic, pro-oxidant, mutagenic and teratogenic, especially if sudden shifts occur in their bodily distribution. Although liver involvement has not been mentioned specifically in recent reports, conventional liver enzyme tests underestimate the true extent of liver dysfunction. The proposed model could be tested by comparing retinoid concentration and expression profiles in microcephalic newborns of ZIKV-infected mothers and nonmicrocephalic newborn controls, and by correlating these profiles with measures of clinical severity.
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Affiliation(s)
- Anthony R. Mawson
- Department of Epidemiology and Biostatistics, School of Public Health (Initiative), Jackson State University, Jackson, Mississippi
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Mawson AR. Role of Fat-Soluble Vitamins A and D in the Pathogenesis of Influenza: A New Perspective. ACTA ACUST UNITED AC 2013. [DOI: 10.5402/2013/246737] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Reduced exposure to solar radiation, leading to a deficiency of vitamin D and hence impaired innate immunity, has been suggested as a trigger for influenza viral replication and as an explanation of seasonal influenza. Although this hypothesis accounts for many unexplained facts about the epidemiology of influenza, gaps remain in understanding the pathogenesis and manifestations of the disease. Several observations suggest a role for vitamin A compounds (retinoids) in the disease. This paper presents a new model of the etiopathogenesis of influenza, suggesting that host resistance and susceptibility depend importantly on the ratio of vitamin D to vitamin A activity. Retinoid concentrations within normal physiological limits appear to inhibit influenza pathogenesis whereas higher background concentrations (i.e., very low vitamin D : A ratios) increase the risk of severe complications of the disease. There is also evidence that influenza-induced or preexisting liver disease, diabetes, and obesity worsen the severity of infection, possibly via liver dysfunction and alterations in retinoid metabolism. The model could be tested by determining the presence of retinoids in the secretions of patients with influenza and by studies of retinoid profiles in patients and controls. Potential strategies for prevention and treatment are discussed.
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Affiliation(s)
- Anthony R. Mawson
- Department of Health Policy and Management, School of Health Sciences, College of Public Service, Jackson State University,
350 West Woodrow Wilson Avenue, Room 229, Jackson, MS 39213, USA
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Miller MS, Mymryk JS. An unhealthy relationship: viral manipulation of the nuclear receptor superfamily. Future Microbiol 2011; 6:999-1019. [PMID: 21958141 DOI: 10.2217/fmb.11.80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The nuclear receptor (NR) superfamily is a diverse group of over 50 proteins whose function is to regulate the transcription of a vast array of cellular genes. These proteins are able to tune transcription over an extremely dynamic range due to the fact that they may act as either transcriptional activators or repressors depending on promoter context and ligand status. Due to these unique properties, diverse families of viruses have evolved strategies to exploit NRs in order to regulate expression of their own genes and to optimize the cellular milieu to facilitate the viral lifecycle. While the specific NRs targeted by these viruses vary, the strategies used to target them are common. This is accomplished at the cis-level by incorporation of nuclear receptor response elements into the viral genome and at the trans-level by viral proteins that target NRs directly or indirectly to modulate their function. The specific NR(s) targeted by a particular virus are likely to be reflective of the tissue tropism of the virus in question. Thus, the essential role played by NRs in the replication cycles of such diverse viruses underscores the importance of understanding their functions in the context of specific infections. This knowledge will allow appropriate considerations to be made when treating infected individuals with hormone-associated diseases and will potentially assist in the rational design of novel antiviral therapeutics.
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Affiliation(s)
- Matthew S Miller
- Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
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Monteiro P, Gosselin A, Wacleche VS, El-Far M, Said EA, Kared H, Grandvaux N, Boulassel MR, Routy JP, Ancuta P. Memory CCR6+CD4+T Cells Are Preferential Targets for Productive HIV Type 1 Infection Regardless of Their Expression of Integrin β7. THE JOURNAL OF IMMUNOLOGY 2011; 186:4618-30. [DOI: 10.4049/jimmunol.1004151] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Alvarez S, Bourguet W, Gronemeyer H, de Lera AR. Retinoic acid receptor modulators: a perspective on recent advances and promises. Expert Opin Ther Pat 2011; 21:55-63. [PMID: 21091043 DOI: 10.1517/13543776.2011.536531] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
IMPORTANCE OF THE FIELD Retinoids are currently used in the clinic for the treatment of skin diseases and acute promielocytic leukemia and are known to contribute to early development and organogenesis in embryo and throughout life. Most of these activities are primarily due to the binding of the retinoid to the retinoic acid receptors (RARs, subtypes α, β and γ). Ligand modulates, via allosteric conformational changes, the ability of RARs to interact with different sets of co-regulators. Structure-based insights on the ligand-binding domain of the ligand-bound RARs have clearly linked retinoid function to co-activator (CoA) recruitment for agonists, CoA dissociation for antagonists and corepressor stabilization for inverse agonists. AREAS COVERED IN THIS REVIEW To help understand ligand-modulated RAR action as a consequence of its interaction with different sets of co-regulators, we present the chemical engineering of subsets of retinoid chemotypes (rexinoids, i.e., the ligands of the retinoid X receptors, α, β and γ, with impact in the treatment of cancer and metabolic diseases, are not covered) that display the whole range of ligand functions, including subtype- and isotype-selectivities. WHAT THE READER WILL GAIN An understanding of the correlation of retinoid ligand structure and function. Structural insights into ligand action and retinoid chemotypes. Potential for clinical application of retinoid receptor modulators. TAKE HOME MESSAGE Potential pharmacological/therapeutic applications of these chemical tools extend beyond cancer prevention and therapy to the treatment of autoimmune and neurodegenerative diseases.
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Affiliation(s)
- Susana Alvarez
- Departamento de Química Orgánica, Facultad de Química, Universidade de Vigo, 36310 Vigo, Spain
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June HL, Tzeng Yang ARS, Bryant JL, Jones O, Royal W. Vitamin A deficiency and behavioral and motor deficits in the human immunodeficiency virus type 1 transgenic rat. J Neurovirol 2010; 15:380-9. [PMID: 19995129 DOI: 10.3109/13550280903350200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) transgenic (Tg) rat model incorporates a noninfectious viral genome that is under similar regulatory control mechanisms in vivo as those that exist with natural infection in humans. Vitamin A (VA) deficiency in humans has been associated with progressive systemic HIV disease and with impaired cognition in rodent models. The effects on of VA deficiency on the development of behavioral abnormalities with HIV infection have not been previously described. In these studies, wild-type (Wt) and Tg rats maintained on either a normal (VA+) or a VA-deficient (VA-) diet were examined for activity in an open field (horizontal activity, total distance, vertical activity, and rearing) and on rotarod testing. On both open field and rotarod testing, the Tg rats performed worse than the Wt rats, with the most severe deficits noted in the TgVA- animals. Analysis of the specific effects of the presence of the HIV transgene and the diet on the performance on the open field tests showed a dominant effect from the transgene on all of the tests, with an effect from the diet on only the number of rearings. On rotarod testing, effects form both the diet and the transgene were observed at lower speeds, at the highest speeds, and on the accelerating rotarod. These studies therefore demonstrate that behavioral and motor abnormalities can be detected in this model and are likely due to similar mechanisms by which humans infected with HIV might develop cognitive-motor impairment in association with VA deficiency.
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Affiliation(s)
- Harry L June
- Department of Neurology, The University of Maryland School of Medicine, Baltimore, Maryland, USA
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Silveira MH, Templet EE, Fronczek FR. Synthesis of 9-Bromo-2-fluoro-6,7-dihydro-5H-benzocycloheptene-8-carboxaldehyde. SYNTHETIC COMMUN 2009. [DOI: 10.1080/00397910802527722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Michael H. Silveira
- a Forensic Science Program, Department of Sciences , Our Lady of the Lake College , Baton Rouge, Louisiana, USA
| | - Erin E. Templet
- a Forensic Science Program, Department of Sciences , Our Lady of the Lake College , Baton Rouge, Louisiana, USA
| | - Frank R. Fronczek
- b Department of Chemistry , Louisiana State University , Baton Rouge, Louisiana, USA
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Royal W, Wang H, Jones O, Tran H, Bryant JL. A vitamin A deficient diet enhances proinflammatory cytokine, Mu opioid receptor, and HIV-1 expression in the HIV-1 transgenic rat. J Neuroimmunol 2007; 185:29-36. [PMID: 17289162 PMCID: PMC1885471 DOI: 10.1016/j.jneuroim.2007.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 12/26/2006] [Accepted: 01/03/2007] [Indexed: 11/25/2022]
Abstract
The HIV-1 (HIV) transgenic (Tg) rat develops several immune abnormalities in association with clinical impairments that are similar to what are seen with HIV infection in humans. In HIV infection, retinoids and opioids can have separate and potentially combined effects on the clinical course of HIV disease. In these studies, the effects of a vitamin A deficient diet on T cell proinflammatory cytokine and mu opioid receptor (MOR) expression were examined in the Tg and in wild-type (WT) rats. The effects of the diet on HIV gene expression were also analyzed in the Tg rats. Phytohemagglutinin-stimulated T cells from WT rats on the vitamin A diet and from Tg rats on either diet were more likely to either produce increased percentages of T cells expressing intracytoplasmic IFN-gamma, secrete higher levels of TNF-alpha, and express higher levels of MOR mRNA and surface MOR. Mitogen stimulation also increased Tg rat HIV env, tat, and nef mRNA expression with even higher env and nef mRNA produced in association with the vitamin A deficient diet. All together, these data suggest that a vitamin A deficient diet can result in cellular effects that increase T cell proinflammatory responses and HIV expression, which may alter the course of disease in the HIV Tg rat model.
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Affiliation(s)
- Walter Royal
- Department of Neurology, University of Maryland School of Medicine, 655 West Baltimore Street, BRB 12-031, Baltimore, MD 21201, USA.
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13
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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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14
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Royal W, Leander M, Chen YE, Major EO, Bissonnette RP. Nuclear receptor activation and interaction with morphine. J Neuroimmunol 2005; 157:61-5. [PMID: 15579281 DOI: 10.1016/j.jneuroim.2004.08.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2004] [Indexed: 12/22/2022]
Abstract
Nervous system disease in HIV infection is associated with toxic damage induced by effects from proinflammatory responses and oxidative stress, and such effects may be more prominent among opioid abusers. In these studies, the effects of activating retinoid receptor (retinoic acid receptor (RAR) and retinoid X receptor (RXR)) and peroxisome proliferator activated receptor (PPAR) gamma, which belong to the steroid-lipid nuclear receptor family, on tumor necrosis factor (TNF)-alpha production and inducible nitric oxide synthase (iNOS) gene expression by stimulated U937 and SVG cells, respectively, were examined. Also studied were the effects of morphine on these responses. These studies showed that, in stimulated cells, the observed responses were suppressed by activation of the nuclear receptors as compared to non-stimulated control cells. Moreover, in phytohemagglutinin (PHA)-stimulated U937 cells, morphine reversed the TNF-alpha suppression that was induced by LG101305 and ciglitazone. Preliminary data in SVG cells suggest a tendency for morphine to have a similar effect on LG101305-exposed SVG cells stimulated with a combination of lipopolysaccharide (LPS) and interferon-gamma, whereas this effect was not induced when these cells were incubated with ciglitazone. Therefore, specific nuclear receptor activation may be potentially beneficial in the treatment of neurological disease associated with HIV infection and may show specific interactions with opioids. The mechanisms that underlie these effects require further study.
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Affiliation(s)
- Walter Royal
- Neuroscience Institute, Morehouse School of Medicine, MRC 214, 720 Westview Drive, S.W., Atlanta, GA 30310, USA.
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15
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Rohr O, Marban C, Aunis D, Schaeffer E. Regulation of HIV-1 gene transcription: from lymphocytes to microglial cells. J Leukoc Biol 2003; 74:736-49. [PMID: 12960235 DOI: 10.1189/jlb.0403180] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transcription is a crucial step for human immunodeficiency virus type 1 (HIV-1) expression in all infected host cells, from T lymphocytes, thymocytes, monocytes, macrophages, and dendritic cells in the immune system up to microglial cells in the central nervous system. To maximize its replication, HIV-1 adapts transcription of its integrated proviral genome by ideally exploiting the specific cellular environment and by forcing cellular stimulatory events and impairing transcriptional inhibition. Multiple cell type-specific interplays between cellular and viral factors perform the challenge for the virus to leave latency and actively replicate in a great diversity of cells, despite the variability of its long terminal repeat region in different HIV strains. Knowledge about the molecular mechanisms underlying transcriptional regulatory events helps in the search for therapeutic agents that target the step of transcription in anti-HIV strategies.
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Affiliation(s)
- Olivier Rohr
- Institut National de la Santé Recherche Médicale Unité, Strasbourg, France
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16
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Abstract
Functional analysis of the roles of the nuclear receptor response elements (NRREs) in the transcription and replication of hepatitis B virus (HBV) in the context of its whole genome has been hampered by the extensive overlapping of the NRREs with the regions encoding viral proteins. We introduced point mutations that inactivate the NRREs individually without altering the open reading frames of viral proteins. These mutations in the context of a plasmid containing 1.2 copies of the HBV genome were transiently transfected into the human hepatoma cell line Huh7. Inactivation of the NRRE in either the preC promoter (NRRE(preC)) or enhancer I (NRRE(enhI)) led to moderate reductions in synthesis of viral RNAs. Concurrent inactivation of both NRREs led to 7- to 8-fold reductions in synthesis of the preC, pregenomic, and preS RNAs and a 15-fold reduction in synthesis of the S RNA. The accumulation of viral DNA in the cytoplasmic nucleocapsids and virion particles in the culture medium was also reduced seven- to eightfold. These results suggest that these NRREs are critical for the efficient propagation of HBV in hepatocytes. In cotransfection experiments we also found that overexpression of PPARalpha-RXRalpha in the presence of their respective ligands led to a fourfold increase in pregenomic RNA synthesis and a four- to fivefold increase in viral DNA synthesis, while it had little or no effect on synthesis of the other viral RNAs. Similar effects were observed with overexpression of PPARgamma-RXRalpha in the presence of their respective ligands. This activation was dependent on NRRE(preC), because the increase in synthesis of viral RNA and DNA was not observed when this site was mutated. Likewise, no activation of synthesis of pregenomic RNA and viral DNA by PPARalpha-RXRalpha was observed in a naturally occurring NRRE(preC)(-) mutant of HBV. Our results suggest that interactions between nuclear receptors and NRREs present in the HBV genome may play critical roles in regulating its transcription and replication during HBV infection of hepatocytes.
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Affiliation(s)
- X Yu
- McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison, Wisconsin 53706-1599, USA
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17
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Recio JA, Martínez de la Mata J, Martín-Nieto J, Aranda A. Retinoic acid stimulates HIV-1 transcription in human neuroblastoma SH-SY5Y cells. FEBS Lett 2000; 469:118-22. [PMID: 10708768 DOI: 10.1016/s0014-5793(00)01249-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Although the brain is an important target for the human immunodeficiency virus type 1 (HIV) and viral infection causes neuronal degeneration and dementia, the mechanisms responsible for HIV transcription in neuronal cells are largely unknown. We show here that retinoic acid (RA) stimulates HIV transcription in human neuronal SH-SY5Y cells. The steroid receptor coactivator 1 (SRC-1) enhances the transcriptional response to RA, and the viral protein Tat cooperates with RA and SRC-1 to induce a strong transactivation. These results suggest that retinoid receptors could play an important role as activators of viral gene expression in the human brain.
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Affiliation(s)
- J A Recio
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Arturo Duperier 4, 28029, Madrid, Spain
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18
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Johnson AT, Wang L, Standeven AM, Escobar M, Chandraratna RA. Synthesis and biological activity of high-affinity retinoic acid receptor antagonists. Bioorg Med Chem 1999; 7:1321-38. [PMID: 10465407 DOI: 10.1016/s0968-0896(99)00055-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This article reports the synthesis and biological activity of new high affinity retinioic acid receptor (RAR) antagonists. The effect of introducing heteroatoms in the bicyclic ring system of the potent dihydronaphthalene RAR antagonist 8, and the variation of the pendant aromatic group on the ability of these compounds to function as RAR antagonists is discussed. The use of binding, transcriptional, and in vivo assays revealed that the 2,2-dimethylthiochromene analogue 59, and the 2,2-dimethylchromene derivative 85, were the most effective in blocking retinoid agonist induced activity.
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Affiliation(s)
- A T Johnson
- Department of Chemistry, Allergan Inc., Irvine, CA 92623-9534, USA.
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19
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Lu XP, Fanjul A, Picard N, Shroot B, Pfahl M. A selective retinoid with high activity against an androgen-resistant prostate cancer cell type. Int J Cancer 1999; 80:272-8. [PMID: 9935210 DOI: 10.1002/(sici)1097-0215(19990118)80:2<272::aid-ijc17>3.0.co;2-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Retinoic acid (RA) and its natural and synthetic analogs, the retinoids, regulate many biological processes, including development, differentiation, cell growth, morphogenesis, metabolism and homeostasis. Retinoid effects are mediated by specific nuclear receptors, the RARs and RXRs. Because of their ability to control cell growth and induce differentiation, retinoids are being examined for the prevention and treatment of several cancers. The majority of retinoids so far analyzed and available inhibit primarily cell proliferation and tumor progression but cannot eliminate cancer cells. In addition, the beneficial effects of the natural retinoids are undermined by undesirable side effects, possibly due to indiscriminate activation of all retinoid receptor subtypes and response pathways. Here, we show that a synthetic retinoid, CD-271, that activates selectively the RAR gamma subtype in a given context, shows increased anti-proliferative activity against certain carcinoma cells over all-trans-retinoic acid (tRA). CD-271 exhibits enhanced activity against DU-145 prostate adenocarcinoma cells through apoptosis-inducing activity, while tRA does not. The selective anti-cancer cell action appears to be receptor-mediated as an RAR antagonist reverses the inhibition. This profile was not seen with other selective retinoids, such as RAR alpha-selective agonists, anti-AP-1 compounds and a non-apoptosis inducing RAR gamma agonist. Our data point to a specific role for RAR gamma in controlling the growth of the prostate, consistent with previous RAR gamma gene knockout data. The identified retinoid represents a new class of compounds with potential for the treatment of prostate cancer.
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Affiliation(s)
- X P Lu
- Sidney Kimmel Cancer Center, San Diego, CA, USA
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20
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Daelemans D, Vandamme AM, De Clercq E. Human immunodeficiency virus gene regulation as a target for antiviral chemotherapy. Antivir Chem Chemother 1999; 10:1-14. [PMID: 10079874 DOI: 10.1177/095632029901000101] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Inhibitors interfering with human immunodeficiency virus (HIV) gene regulation may have great potential in anti-HIV drug (combination) therapy. They act against different targets to currently used anti-HIV drugs, reduce virus production from acute and chronically infected cells and are anticipated to elicit less virus drug resistance. Several agents have already proven to inhibit HIV gene regulation in vitro. A first class of compounds interacts with cellular factors that bind to the long terminal repeat (LTR) promoter and that are needed for basal level transcription, such as NF-kappa B and Sp1 inhibitors. A second class of compounds specifically inhibits the transactivation of the HIV LTR promoter by the viral Tat protein, such as the peptoid CGP64222. A third class of compounds prevents the accumulation of single and unspliced mRNAs through inhibition of the viral regulator protein Rev, such as the aminoglycosidic antibiotics. Most of these compounds have been tested in specific transactivation assays. Whether they are active at the postulated target in virus replication assays has, for many of them, not been ascertained. Toxicity data are often lacking or insufficient. Yet these data are crucial in view of the toxicity that may be expected for compounds that primarily interact with cellular factors. Although a promising lead, considerable research is still required before gene regulation inhibitors may come of age as clinically useful agents.
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Affiliation(s)
- D Daelemans
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
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21
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Le Jossic C, Michel D. Striking evolutionary conservation of a cis-element related to nuclear receptor target sites and present in TR2 orphan receptor genes. Biochem Biophys Res Commun 1998; 245:64-9. [PMID: 9535784 DOI: 10.1006/bbrc.1998.8376] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A systematic scanning of nucleic acid databases for DNA elements made of combinations of RGGTCA nuclear receptor half sites, has revealed that identical 19 nucleotide-long motifs composed of two inverted RGGTCA sites with a spacing of 7 nucleotides (IR7), are present upstream of the regions coding for the human TR2 and of the sea urchin SpSHR2 orphan receptors. We have developed an experimental strategy based on PCR, to check if this IR7 could correspond to an unusually long cis-element, conserved along evolution and regulating the TR2 genes. We found that indeed IR7 is present in the 5' untranslated region of TR2 genes from all species tested, including Xenopus, rainbow trout, zebrafish and mouse. The exact conservation throughout the animal kingdom of such a long, non repetitive and non coding genomic region, highly suggests that it should ensure important biological functions. In addition, this work has allowed the identification of a new, non coding, upstream exon in the mouse TR2 gene present in testicular TR2 mRNAs.
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Affiliation(s)
- C Le Jossic
- Laboratoire d'Endocrinologie Moléculaire de la Reproduction, UPRESA 6026 CNRS-Université de Rennes 1, Campus de Beaulieu, Rennes, 35042, France
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22
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Abstract
The brain is an important target for the human immunodeficiency virus type 1 (HIV-1). We show here that nerve growth factor (NGF), which induces neuronal differentiation and survival, causes a strong activation of the HIV-1 long terminal repeat by a Ras/Raf-dependent mechanism in PC12 cells. Mutation of the kappaB sequences contained whithin the long terminal repeat reduces NGF-mediated stimulation. NGF does not activate NF-kappaB in PC12 cells, but rather increases binding of other nuclear factors to the kappaB sequences. Furthermore, a nuclear receptor response element contributes to the stimulatory effect of NGF. The retinoids receptors have been identified as components of the nuclear binding to the nuclear receptor response element in NGF-treated PC12 cells. These results reveal the importance of neurotrophins and nuclear receptor signaling pathways as specific activators of HIV-1 gene expression in neural cells.
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Affiliation(s)
- J A Recio
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Arturo Duperier 4, 28029 Madrid, Spain
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23
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Lee AW, Mitra D, Laurence J. Interaction of pregnancy steroid hormones and zidovudine in inhibition of HIV type 1 replication in monocytoid and placental Hofbauer cells: implications for the prevention of maternal-fetal transmission of HIV. AIDS Res Hum Retroviruses 1997; 13:1235-42. [PMID: 9310291 DOI: 10.1089/aid.1997.13.1235] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Zidovudine (AZT) has been shown to reduce maternal-fetal transmission of HIV-1 by more than two-thirds in a variety of clinical settings. However, the mechanism of action of AZT in this setting is unclear. Suppression of vertical transmission has occurred in the absence of an impact on maternal plasma viremia and no lower threshold of viral load for such transmission has been identified. We hypothesized that augmentation of the anti-HIV effect of AZT may occur locally, at the maternal-fetal interface. We report that the pregnancy hormone progesterone at broad concentrations has little effect on acute HIV-1 infection of a monocytic cell line or primary peripheral blood cells. However, the combination of physiologic concentrations of progesterone (10[-7] to 10[-6] M) and low-dose AZT (10[-8] to 10[-9] M) produced markedly synergistic inhibition of HIV-1 replication within acutely infected monocytic cell lines (U937), and additive inhibition of HIV-1 growth within chronically infected monocytic cells (U1) and primary placental macrophages (Hofbauer cells). Anti-HIV effects were not seen with another pregnancy steroid hormone, estrogen. In terms of possible mechanisms of action for progesterone, we demonstrated that it incompletely suppressed tat activation of long terminal repeat (LTR)-driven gene expression in monocytic cells. However, the progesterone-mediated suppession of tat activation was not affected by mutation of the three consensus progesterone/androgen/glucocorticoid response elements within the HIV-1 LTR, previously shown by our group to be involved in glucocorticoid-mediated suppression of LTR-driven transcription. It is likely that progesterone suppresses LTR-driven gene expression through a nontranscriptional mechanism, and augments the efficacy of AZT through enhancement of its phosphorylation.
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Affiliation(s)
- A W Lee
- Department of Medicine, Cornell University Medical College, New York, New York 10021, USA
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24
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Affiliation(s)
- P Ghazal
- Departments of Immunology and Neuropharmacology, Division of Virology R307B, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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25
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Schwartz C, Canonne-Hergaux F, Aunis D, Schaeffer E. Characterization of nuclear proteins that bind to the regulatory TGATTGGC motif in the human immunodeficiency virus type 1 long terminal repeat. Nucleic Acids Res 1997; 25:1177-84. [PMID: 9092627 PMCID: PMC146561 DOI: 10.1093/nar/25.6.1177] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have recently elucidated the nature and function of transcription factors present in Jurkat, glial and neuronal cells that interact with modulatory region B, the nuclear receptor responsive element, in the long terminal repeat of human immunodeficiency virus type 1 (HIV-1). Considering the key role that the combination of host cell proteins plays in HIV-1 gene transcription, it appears essential to characterize proteins interacting with the adjacent region A. In vitro experiments revealed that the 5'-TGATTGGC-3'motif of region A is the target for at least three distinct proteins, one belonging to the nuclear factor I family, while two others are related to the cAMP response element binding (CREB) protein family. One of these proteins, present in DNA-protein complex C2, is formed by distinct polypeptides of relative molecular mass 43 000 and 50 000. We have purified the 43 kDa protein, which is distinct from CREB-43, and have shown that renatured p43 is able to specifically interact with site A. Transient expression experiments with vectors containing wild-type or mutant motif A revealed that basal HIV-1 gene transcription in Jurkat cells is regulated by antagonistic effects of the site A binding proteins.
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Affiliation(s)
- C Schwartz
- Unité 338 INSERM, Centre de Neurochimie, 5 rue Blaise Pascal, 67084 Strasbourg Cedex, France
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26
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Barger PM, Kelly DP. Identification of a retinoid/chicken ovalbumin upstream promoter transcription factor response element in the human retinoid X receptor gamma2 gene promoter. J Biol Chem 1997; 272:2722-8. [PMID: 9006910 DOI: 10.1074/jbc.272.5.2722] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To investigate the mechanisms involved in the transcriptional control of retinoid X receptor (RXR) gene expression, the 5'-flanking region of the human RXRgamma2 isoform was characterized. An imperfect hexamer repeat (gamma retinoid X response element; gammaRXRE) with a single nucleotide spacer (GGTTGAaAGGTCA) was identified immediately upstream of the RXRgamma2 gene transcription start site. Cotransfection studies in CV-1 cells with expression vectors for the retinoid receptors RXRalpha and retinoic acid receptor beta (RARbeta) demonstrated that the gammaRXRE confers retinoid-mediated transcriptional activation with preferential activation by RXR in the presence of its cognate ligand, 9-cis-retinoic acid (RA). Electrophoretic mobility shift assays demonstrated that RXR homodimer binding to gammaRXRE is markedly enhanced by 9-cis-RA, whereas RAR.RXR heterodimer binding is ligand-independent. DNA binding studies and cell cotransfection experiments also demonstrated that the nuclear receptor, chicken ovalbumin upstream promoter transcription factor (COUP-TF), repressed transcription via the gammaRXRE. Cotransfection experiments revealed that COUP-TF and RXRalpha compete at the gammaRXRE to modulate transcription bidirectionally over a wide range. These results demonstrate that the human RXRgamma2 gene promoter contains a novel imperfect repeat element capable of mediating RXR-dependent transcriptional autoactivation and COUP-TF-dependent repression.
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Affiliation(s)
- P M Barger
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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27
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Zuo F, Kraus RJ, Gulick T, Moore DD, Mertz JE. Direct modulation of simian virus 40 late gene expression by thyroid hormone and its receptor. J Virol 1997; 71:427-36. [PMID: 8985367 PMCID: PMC191068 DOI: 10.1128/jvi.71.1.427-436.1997] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Transcription of the late genes of simian virus 40 (SV40) is repressed during the early phase of the lytic cycle of infection of primate cells by the binding of cellular factors, called IBP-s, to the SV40 late promoter; repression is relieved after the onset of viral DNA replication by titration of these repressors (S. R. Wiley, R. J. Kraus, F. R. Zuo, E. E. Murray, K. Loritz, and J. E. Mertz, Genes Dev. 7:2206-2219, 1993). Recently, we showed that IBP-s consists of several members of the steroid/thyroid hormone receptor superfamily (F. Zuo and J. E. Mertz, Proc. Natl. Acad. Sci. USA 92:8586-8590, 1995). Here, we show that the thyroid hormone receptor TRalpha1, in combination with retinoid X receptor alpha (RXRalpha), is specifically bound at the transcriptional initiation site of the major late promoter of SV40. This binding repressed transcription from the SV40 late promoter by preventing the formation of pre-initiation complexes. Addition of the thyroid hormone 3,5,3'-L-triiodothyronine (T3) resulted in reversal of this repression in cotransfected CV-1 cells. Interestingly, repression did not occur when this thyroid response element (TRE) was translocated to 50 bp upstream of the major late initiation site. Binding of TRalpha1/RXRalpha heterodimers to this TRE induced bending of the promoter DNA. We conclude that hormones and their receptors can directly affect the expression of SV40, probably by affecting protein-protein and protein-DNA interactions involved in the formation of functional preinitiation complexes.
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Affiliation(s)
- F Zuo
- McArdle Laboratory For Cancer Research, University of Wisconsin Medical School, Madison 53706-1599, USA
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28
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Sawaya BE, Rohr O, Aunis D, Schaeffer E. Chicken ovalbumin upstream promoter transcription factor, a transcriptional activator of HIV-1 gene expression in human brain cells. J Biol Chem 1996; 271:23572-6. [PMID: 8798567 DOI: 10.1074/jbc.271.38.23572] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Viral infection of the central nervous system by the human immunodeficiency virus type 1 leads to a wide range of neuropathological disorders. However, the molecular mechanisms governing transcription of the human immunodeficiency virus type 1 genome in brain remain unclear. We have recently established that in brain cells, proteins belonging to the steroid/thyroid/retinoic acid receptor family bind to the -352 to -320 region of the long terminal repeat (LTR). Here, by supershift experiments, we have identified chicken ovalbumin upstream promoter transcription factor (COUP-TF), an orphan member of this nuclear receptor family, as one of the major proteins interacting with this LTR site. Cotransfection studies revealed that COUP-TF is able to dramatically activate LTR-directed gene transcription in human oligodendroglioma but not in astrocytoma cells. This activation occurs through two mechanisms, depending on the LTR sequence. Moreover, in neuronal cells COUP-TF and dopamine, a catecholamine neurotransmitter, enhance LTR-directed transcription by acting on the proximal LTR region. These results reveal the importance of COUP-TF and the dopamine signaling pathway as activators of human immunodeficiency virus type 1 gene expression in brain.
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Affiliation(s)
- B E Sawaya
- Unité 338 INSERM, 5, rue Blaise Pascal, 67084 Strasbourg, France
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29
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Kingsman SM, Kingsman AJ. The regulation of human immunodeficiency virus type-1 gene expression. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 240:491-507. [PMID: 8856047 DOI: 10.1111/j.1432-1033.1996.0491h.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Despite 15 years of intensive research we still do not have an effective treatment for AIDS, the disease caused by human immunodeficiency virus (HIV). Recent research is, however, revealing some of the secrets of the replication cycle of this complex retrovirus, and this may lead to the development of novel antiviral compounds. In particular the virus uses strategies for gene expression that seem to be unique in the eukaryotic world. These involve the use of virally encoded regulatory proteins that mediate their effects through interactions with specific viral target sequences present in the messenger RNA rather than in the proviral DNA. If there are no cellular counterparts of these RNA-dependent gene-regulation pathways then they offer excellent targets for the development of antiviral compounds. The viral promoter is also subject to complex regulation by combinations of cellular factors that may be functional in different cell types and at different cell states. Selective interference of specific cellular factors may also provide a route to inhibiting viral replication without disrupting normal cellular functions. The aim of this review is to discuss the regulation of HIV-1 gene expression and, as far as it is possible, to relate the observations to viral pathogenesis. Some areas of research into the regulation of HIV-1 replication have generated controversy and rather than rehearsing this controversy we have imposed our own bias on the field. To redress the balance and to give a broader view of HIV-1 replication and pathogenesis we refer you to a number of excellent reviews [Cullen, B. R. (1992) Microbiol. Rev. 56, 375-394; Levy, J. A. (1993) Microbiol. Rev. 57, 183-394; Antoni, B. A., Stein, S. & Rabson, A. B. (1994) Adv. Virus Res. 43, 53-145; Rosen, C. A. & Fenyoe, E. M. (1995) AIDS (Phila.) 9, S1-S3].
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MESH Headings
- Acquired Immunodeficiency Syndrome/prevention & control
- Acquired Immunodeficiency Syndrome/therapy
- Amino Acid Sequence
- Base Sequence
- Enhancer Elements, Genetic
- Gene Expression Regulation, Viral
- Gene Products, tat/physiology
- Genome, Viral
- HIV Long Terminal Repeat
- HIV-1/genetics
- HIV-1/physiology
- Humans
- Models, Genetic
- Molecular Sequence Data
- Nucleic Acid Conformation
- Promoter Regions, Genetic
- RNA Processing, Post-Transcriptional
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA-Binding Proteins/metabolism
- TATA Box
- Transcription, Genetic
- Virus Replication
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- S M Kingsman
- Department of Biochemistry, University of Oxford, England
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30
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Sawaya BE, Rohr O, Aunis D, Schaeffer E. Regulation of human immunodeficiency virus type 1 gene transcription by nuclear receptors in human brain cells. J Biol Chem 1996; 271:22895-900. [PMID: 8798469 DOI: 10.1074/jbc.271.37.22895] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Infection of cells of the central nervous system by the human immunodeficiency virus type-1 (HIV-1) leads to HIV-1-associated neuropathology. Recent studies have demonstrated the importance of long terminal repeat (LTR) binding sites in determining the pathogenicity of HIV. Here we have investigated the presence and the functional role of transcription factors that have the potential to interact, directly or indirectly, with the nuclear receptor-responsive element in the LTR of HIV-1, in different human cell lines of the brain. Cotransfection experiments showed that in oligodendroglioma TC-620 cells, the retinoic acid receptor and the retinoid X receptor activate LTR-driven transcription in the absence of ligand. Addition of all-trans- or 9-cis-retinoic acid reverses this effect. In contrast, in astrocytoma, neuronal, and microglial cells, no significant effect of the retinoid acid pathway was detected. This retinoid response is mediated by distinct molecular interactions in the lymphotropic LAI and the neurotropic JR-CSF HIV-1 strains. Moreover, retinoid receptors were found to antagonize the chicken ovalbumin upstream promoter transcription factor- as well as the c-JUN-mediated LTR transactivation. Our findings demonstrate the importance of the retinoic acid signaling pathway and of cross-coupling interactions in the repression of HIV-1 LTR gene expression.
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Affiliation(s)
- B E Sawaya
- Unité 338 INSERM, 5, rue Blaise Pascal, 67084 Strasbourg Cedex, France
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31
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La Vista-Picard N, Hobbs PD, Pfahl M, Dawson MI, Pfahl M. The receptor-DNA complex determines the retinoid response: a mechanism for the diversification of the ligand signal. Mol Cell Biol 1996; 16:4137-46. [PMID: 8754812 PMCID: PMC231410 DOI: 10.1128/mcb.16.8.4137] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To obtain insights into the principles governing the complex biological responses to retinoids, we have analyzed the ligand sensitivities of various retinoid receptor-DNA complexes. We find that different retinoid receptor heterodimers show distinct activation patterns with various response elements while a given heterodimer can be activated at different retinoic acid concentrations on different response elements. In vitro binding experiments suggest that the same retinoic acid receptor-retinoid X receptor (RAR-RXR) heterodimer can have different ligand affinities, depending on the response element it is bound to. The differential responses of a particular receptor heterodimer with various retinoic acid responsive elements can be enhanced through the use of conformationally restricted retinoids. RAR- and RXR-selective retinoids can also synergistically activate the receptor heterodimers, indicating that both partners in the heterodimer can contribute to ligand-induced transcriptional activation. However, the relative influence of the RAR or RXR partner is specific for each response element. Together, our data demonstrate that it is the receptor-DNA complex and not the receptor alone that determines the ligand response. This flexibility allows for a highly pleiotropic retinoid response. Furthermore, conformationally restricted retinoids can accentuate the differential responses and exhibit a certain degree of gene selectivity by differentially activating the RAR or RXR component in the context of a given response element.
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32
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Zoumpourlis V, Ergazaki M, Spandidos DA. Transcriptional Activation of the Human Immunodeficiency Virus Long Terminal Repeat Sequences by Retinoic Acid in Human Epithelial and Fibroblast Tumor Cell Lines. Int J Biol Markers 1996; 11:153-8. [PMID: 8915710 DOI: 10.1177/172460089601100303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We employed a recombinant plasmid, pBHIV1, carrying the long terminal repeat (LTR) sequences of HIV-1 linked to the reporter chloramphenicol acetyl transferase (CAT) gene and to the aminoglycoside phosphotransferase (aph) gene as a selectable marker. We introduced pBHIV1 into human epithelial and fibroblast tumor cell lines (HeLa and MRCSV40TGR), and obtained stable geneticin-resistant HLHIV1-A and SVTGHIV1-A cells, respectively. The response to the retinoic acid was studied on the LTR regulated CAT activity in both cell lines. It was found that retinoic acid at a concentration of 1×10−5effects a 3.2 - fold increase in CAT expression compared to HIV LTR in HLHIV1-A, but requires a concentration of 5×10−5M to enhance this expression 4.6-fold in SVTGHIV1-A cells. These data show that retinoic acid may play a critical role in HIV-1 expression in human epithelial and fibroblast cell lines.
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Affiliation(s)
- V Zoumpourlis
- Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece
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33
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Lee MO, Dawson MI, Picard N, Hobbs PD, Pfahl M. A novel class of retinoid antagonists and their mechanism of action. J Biol Chem 1996; 271:11897-903. [PMID: 8662628 DOI: 10.1074/jbc.271.20.11897] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Retinoids regulate a broad range of biological processes through two subfamilies of nuclear retinoid receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). Recently, we reported a novel type of retinoic acid antagonist (SR11335) and showed that this compound can inhibit retinoic acid (RA)-induced activation of a human immunodeficiency virus type 1 (HIV-1) promoter construct that contains a special RA response element (RARE). We have now further characterized the antagonism mediated by SR11335 and of newly synthesized structurally related compounds. Two compounds, SR11330 and SR11334, which are poor transactivators, also showed antagonist activities, inhibiting all-trans-RA (tRA) and 9-cis-RA. The retinoids inhibited transcriptional activation of RAR/RXR heterodimers effectively, while inhibition of RXR homodimers was less efficient. Inhibition was observed on several RAREs, including the TREpal, betaRARE, apoAI-RARE, and CRBPI-RARE. In addition, the antagonists inhibited tRA-induced differentiation of HL-60 cells. The antagonist did not interfere with DNA binding of the receptors. In limited proteolytic digestion assays, SR11335 induced resistance of the receptors to proteolysis, but the pattern of the degradation was not altered from that induced by tRA, suggesting that these antagonists induce their biological effects by competing with agonists for binding to RARs, thereby preventing the induction of conformational changes of the receptors necessary for transcriptional activation.
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Affiliation(s)
- M O Lee
- Sidney Kimmel Cancer Center, La Jolla, California 92037, USA
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34
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Bouterfa HL, Piedrafita FJ, Doenecke D, Pfahl M. Regulation of H1(0) gene expression by nuclear receptors through an unusual response element: implications for regulation of cell proliferation. DNA Cell Biol 1995; 14:909-19. [PMID: 7576177 DOI: 10.1089/dna.1995.14.909] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cloning and sequence analysis of the 5'-flanking region of the human H1(0) histone gene, a differentiation-specific member of the H1 family, has revealed several potential regulatory elements. In this study, we have characterized the interactions of nuclear receptors with an unusual response element consisting of two half-sites arranged as a direct repeat with an 8-bp spacer (DR-8). Thyroid hormone receptors (TR) bind this DR-8 as homodimers and heterodimers with RXR. Retinoic acid receptors (RARs) also bind as heterodimers with RXR to the DR-8, and this binding is enhanced in the presence of retinoic acid (RA) and/or 9-cis RA. Reporter constructs containing the DR-8 allowed a several-fold induction by T3 in the presence of TRs. RAR alpha and RAR beta allowed RA-dependent transcriptional activation whereas RAR gamma mostly increased basal activity. 9-cis RA inhibited the T3 response, indicating a hormonal cross-talk among the subfamily of nuclear receptors. Two orphan receptors, COUP-TF and v-erbA, also bind the DR-8 sequence in the human H1(0) promoter. COUP-TF, which usually represses RAREs, enhances transcriptional activation through the DR-8 whereas v-erbA completely represses TR-RXR induction of the H1(0) gene. Thus, a number of signaling pathways that play important roles during development and differentiation are able to influence the transcription rate of this special H1 subtype directly through a DR-8 response element in its promoter. Because H1(0) expression levels inversely correlate with cell proliferation, our data suggest that several nuclear receptors and the v-erbA oncogene can influence cell proliferation via the regulation of H1(0) expression.
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Affiliation(s)
- H L Bouterfa
- Sidney Kimmel Cancer Center, La Jolla, CA 92037, USA
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35
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Zuo F, Mertz JE. Simian virus 40 late gene expression is regulated by members of the steroid/thyroid hormone receptor superfamily. Proc Natl Acad Sci U S A 1995; 92:8586-90. [PMID: 7567979 PMCID: PMC41011 DOI: 10.1073/pnas.92.19.8586] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Transcription of the late genes of simian virus 40 (SV40) is repressed during the early phase of the lytic cycle of infection of binding of cellular factors, called IBP-s, to the SV40 late promoter; repression is relieved after the onset of viral DNA replication by titration of these repressors. Preliminary data indicated that one of the major components of IBP-s was human estrogen-related receptor 1 (hERR1). We show here that several members of the steroid/thyroid hormone receptor superfamily, including testis receptor 2, thyroid receptor alpha 1 in combination with retinoid X receptor alpha, chicken ovalbumin upstream promoter transcription factors 1 and 2 (COUP-TF1 and COUP-TF2), as well as hERR1, possess the properties of IBP-s. These receptors bind specifically to hormone receptor binding sites present in the SV40 major late promoter. Recombinant COUP-TF1 specifically represses transcription from the SV40 major late promoter in a cell-free transcription system. Expression of COUP-TF1, COUP-TF2, or hERR1 in monkey cells results in repression of the SV40 late promoter, but not the early promoter, in the absence of the virally encoded large tumor antigen. Overexpression of COUP-TF1 leads to a delay in the early-to-late switch in SV40 gene expression during the lytic cycle of infection. Thus, members of this superfamily can play major direct roles in regulating expression of SV40. Possibly, natural or synthetic ligands to these receptors can serve as antiviral drugs. Our findings also provide the basis for the development of assays to screen for the ligands to testis receptor 2 and hERR1.
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MESH Headings
- Antigens, Viral, Tumor/metabolism
- Base Sequence
- COUP Transcription Factor I
- COUP Transcription Factors
- DNA Replication
- DNA-Binding Proteins/metabolism
- Gene Expression Regulation, Viral
- Genes, Switch
- HeLa Cells
- Humans
- Molecular Sequence Data
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Promoter Regions, Genetic
- Protein Binding
- Protein Conformation
- Proteins/metabolism
- Receptors, Cytoplasmic and Nuclear
- Receptors, Estrogen/metabolism
- Receptors, Retinoic Acid/metabolism
- Receptors, Steroid/metabolism
- Receptors, Thyroid Hormone/metabolism
- Retinoid X Receptors
- Simian virus 40/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
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Affiliation(s)
- F Zuo
- McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison 53706-1599, USA
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36
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Goodman AB. Chromosomal locations and modes of action of genes of the retinoid (vitamin A) system support their involvement in the etiology of schizophrenia. AMERICAN JOURNAL OF MEDICAL GENETICS 1995; 60:335-48. [PMID: 7485272 DOI: 10.1002/ajmg.1320600415] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Vitamin A (retinoid), an essential nutrient for fetal and subsequent mammalian development, is involved in gene expression, cell differentiation, proliferation, migration, and death. Retinoic acid (RA) the morphogenic derivative of vitamin A is highly teratogenic. In humans retinoid excess or deficit can result in brain anomalies and psychosis. This review discusses chromosomal loci of genes that control the retinoid cascade in relation to some candidate genes in schizophrenia. The paper relates the knowledge about the transport, delivery, and action of retinoids to what is presently known about the pathology of schizophrenia, with particular reference to the dopamine hypothesis, neurotransmitters, the glutamate hypothesis, retinitis pigmentosa, dermatologic disorders, and craniofacial anomalies.
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Affiliation(s)
- A B Goodman
- Statistical Sciences and Epidemiology Division, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
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37
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Lee MO, Liu Y, Zhang XK. A retinoic acid response element that overlaps an estrogen response element mediates multihormonal sensitivity in transcriptional activation of the lactoferrin gene. Mol Cell Biol 1995; 15:4194-207. [PMID: 7623814 PMCID: PMC230658 DOI: 10.1128/mcb.15.8.4194] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The lactoferrin gene is highly expressed in many different tissues, and its expression is controlled by different regulators. In this report, we have defined a retinoic acid response element (RARE) in the 5'-flanking region of the lactoferrin gene promoter. The lactoferrin-RARE is composed of two AGGTCA-like motifs arranged as a direct repeat with 1-bp spacing (DR-1). A gel retardation assay demonstrated that it bound strongly with retinoid X receptor (RXR) homodimers and RXR-retinoic acid receptor (RAR) heterodimers as well as chicken ovalbumin upstream promoter transcription factor (COUP-TF) orphan receptor. In CV-1 cells, the lactoferrin-RARE linked with a heterologous thymidine kinase promoter was strongly activated by RXR homodimers in response to 9-cis-retinoic acid (9-cis-RA) but not to all-trans-RA. When the COUP-TF orphan receptor was cotransfected, the 9-cis-RA-induced RXR homodimer activity was strongly repressed. A unique feature of the lactoferrin-RARE is that it has an AGGTCA-like motif in common with an estrogen-responsive element (ERE). The composite RARE/ERE contributes to the functional interaction between retinoid receptors and the estrogen receptor (ER) and their ligands. In CV-1 cells, cotransfection of the retinoid and estrogen receptors led to mutual inhibition of the other's activity, while an RA-dependent inhibition of ER activity was observed in breast cancer cells. Furthermore, the lactoferrin-RARE/ERE showed differential transactivation activity in different cell types. RAs could activate the lactoferrin-RARE/ERE in human leukemia HL-60 cells and U937 cells but not in human breast cancer cells. By gel retardation analyses, we demonstrated that strong binding of the endogenous COUP-TF in breast cancer cells to the composite element contributed to diminished RA response in these cells. Thus, the lactoferrin-RARE/ERE functions as a signaling switch module that mediates multihormonal responsiveness in the regulation of lactoferrin gene expression.
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Affiliation(s)
- M O Lee
- La Jolla Cancer Research Foundation, Cancer Research Center, California 92037, USA
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38
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Bendik I, Pfahl M. Similar ligand-induced conformational changes of thyroid hormone receptors regulate homo- and heterodimeric functions. J Biol Chem 1995; 270:3107-14. [PMID: 7852392 DOI: 10.1074/jbc.270.7.3107] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Thyroid hormone receptors (TRs) bind specific thyroid hormone response elements (TREs) as heterodimers with retinoid X receptors (RXRs) and act as transcriptional activators. As homodimers, TRs can bind a distinct set of sequences and function as ligand sensitive repressors. In our study, we compared the natural malic enzyme TRE (ME-TRE) as a model system for the TR/RXR heterodimer pathway to the chicken lysozyme silencer element F2-TRE which is strongly bound and regulated by TR/TR homodimers. Using electrophoretic mobility shift assays, transient transfections with a variety of natural and synthetic triiodothyronine and thyroxine derivatives as well as limited proteolytic analysis, we show that the natural homo- and heterodimeric pathways show similar ligand requirements. Furthermore, we observe that the ligand-induced conformational changes in the receptor proteins that either result in a loss of TR/TR homodimer binding and release of transcriptional repression or in transcriptional activation of TR/RXR heterodimers are indistinguishable. Therefore, we propose that in TR/TR homodimers and TR/RXR heterodimers very similar moieties of the receptors are involved in ligand binding and subsequent conformational changes that lead to loss of gene repression (TR/TR homodimer) and gain of gene activation (TR/RXR heterodimer).
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Affiliation(s)
- I Bendik
- Cancer Center, La Jolla Cancer Research Foundation, California 92037
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39
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Chapter 13. Retinoids for the Treatment of Oncological Disease. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1995. [DOI: 10.1016/s0065-7743(08)60926-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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40
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Fanjul A, Dawson MI, Hobbs PD, Jong L, Cameron JF, Harlev E, Graupner G, Lu XP, Pfahl M. A new class of retinoids with selective inhibition of AP-1 inhibits proliferation. Nature 1994; 372:107-11. [PMID: 7969403 DOI: 10.1038/372107a0] [Citation(s) in RCA: 246] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Retinoids regulate many biological processes, including differentiation, morphogenesis and cell proliferation. They are also important therapeutic agents, but their clinical usefulness is limited because of side effects. Retinoid activities are mediated by specific nuclear receptors, the RARs and RXRs, which can induce transcriptional activation through specific DNA sites or by inhibiting the transcription factor AP-1 (refs 12-15), which usually mediates cell proliferation signals. Because the two types of receptor actions are mechanistically distinct, we investigated whether conformationally restricted retinoids, selective for each type of receptor action, could be identified. Here we describe a new class of retinoids that selectively inhibits AP-1 activity but does not activate transcription. These retinoids do not induce differentiation in F9 cells but inhibit effectively the proliferation of several tumour cell lines, and could thus serve as candidates for new retinoid therapeutic agents with reduced side effects.
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Affiliation(s)
- A Fanjul
- Cancer Center, La Jolla Cancer Research Foundation, La Jolla, California 92037
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41
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A novel orphan receptor specific for a subset of thyroid hormone-responsive elements and its interaction with the retinoid/thyroid hormone receptor subfamily. Mol Cell Biol 1994. [PMID: 7935418 DOI: 10.1128/mcb.14.10.7025] [Citation(s) in RCA: 217] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The steroid/hormone nuclear receptor superfamily comprises several subfamilies of receptors that interact with overlapping DNA sequences and/or related ligands. The thyroid/retinoid hormone receptor subfamily has recently attracted much interest because of the complex network of its receptor interactions. The retinoid X receptors (RXRs), for instance, play a very central role in this subfamily, forming heterodimers with several receptors. Here we describe a novel member of this subfamily that interacts with RXR. Using a v-erbA probe, we obtained a cDNA which encodes a novel 445-amino-acid protein, RLD-1, that contains the characteristic domains of nuclear receptors. Northern (RNA) blot analysis showed that in mature rats, the receptor is highly expressed in spleen, pituitary, lung, liver, and fat. In addition, weaker expression is observed in several other tissues. Amino acid sequence alignment and DNA-binding data revealed that the DNA-binding domain of the new receptor is related to that of the thyroid/retinoid subgroup of nuclear receptors. RLD-1 preferentially binds as a heterodimer with RXR to a direct repeat of the half-site sequence 5'-G/AGGTCA-3', separated by four nucleotides (DR-4). Surprisingly, this binding is dependent to a high degree on the nature of the spacing nucleotides. None of the known nuclear receptor ligands activated RLD-1. In contrast, a DR-4-dependent constitutive transcriptional activation of a chloramphenicol acetyltransferase reporter gene by the RLD-1/RXR alpha heterodimer was observed. Our data suggest a highly specific role for this novel receptor within the network of gene regulation by the thyroid/retinoid receptor subfamily.
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42
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Apfel R, Benbrook D, Lernhardt E, Ortiz MA, Salbert G, Pfahl M. A novel orphan receptor specific for a subset of thyroid hormone-responsive elements and its interaction with the retinoid/thyroid hormone receptor subfamily. Mol Cell Biol 1994; 14:7025-35. [PMID: 7935418 PMCID: PMC359232 DOI: 10.1128/mcb.14.10.7025-7035.1994] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The steroid/hormone nuclear receptor superfamily comprises several subfamilies of receptors that interact with overlapping DNA sequences and/or related ligands. The thyroid/retinoid hormone receptor subfamily has recently attracted much interest because of the complex network of its receptor interactions. The retinoid X receptors (RXRs), for instance, play a very central role in this subfamily, forming heterodimers with several receptors. Here we describe a novel member of this subfamily that interacts with RXR. Using a v-erbA probe, we obtained a cDNA which encodes a novel 445-amino-acid protein, RLD-1, that contains the characteristic domains of nuclear receptors. Northern (RNA) blot analysis showed that in mature rats, the receptor is highly expressed in spleen, pituitary, lung, liver, and fat. In addition, weaker expression is observed in several other tissues. Amino acid sequence alignment and DNA-binding data revealed that the DNA-binding domain of the new receptor is related to that of the thyroid/retinoid subgroup of nuclear receptors. RLD-1 preferentially binds as a heterodimer with RXR to a direct repeat of the half-site sequence 5'-G/AGGTCA-3', separated by four nucleotides (DR-4). Surprisingly, this binding is dependent to a high degree on the nature of the spacing nucleotides. None of the known nuclear receptor ligands activated RLD-1. In contrast, a DR-4-dependent constitutive transcriptional activation of a chloramphenicol acetyltransferase reporter gene by the RLD-1/RXR alpha heterodimer was observed. Our data suggest a highly specific role for this novel receptor within the network of gene regulation by the thyroid/retinoid receptor subfamily.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cells, Cultured
- Cloning, Molecular
- DNA-Binding Proteins
- Gene Expression Regulation
- Liver X Receptors
- Molecular Sequence Data
- Orphan Nuclear Receptors
- Protein Binding
- Rats
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Retinoic Acid/classification
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Receptors, Thyroid Hormone/classification
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/metabolism
- Regulatory Sequences, Nucleic Acid
- Retinoid X Receptors
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Thyroid Hormones/metabolism
- Tissue Distribution
- Transcription Factors
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Affiliation(s)
- R Apfel
- La Jolla Cancer Research Foundation, California 92037
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43
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Pfahl M, Apfel R, Bendik I, Fanjul A, Graupner G, Lee MO, La-Vista N, Lu XP, Piedrafita J, Ortiz MA. Nuclear retinoid receptors and their mechanism of action. VITAMINS AND HORMONES 1994; 49:327-82. [PMID: 7810073 DOI: 10.1016/s0083-6729(08)61150-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M Pfahl
- La Jolla Cancer Research Foundation, California 92037
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