1
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Hoekstra M, Ren B, Laurila PP, Hildebrand RB, Soronen J, Frodermann V, Li Z, Boon MR, Geerling JJ, Rensen PCN, Jauhiainen M, Van Eck M. Hematopoietic upstream stimulating factor 1 deficiency is associated with increased atherosclerosis susceptibility in LDL receptor knockout mice. Sci Rep 2021; 11:16419. [PMID: 34385562 PMCID: PMC8361089 DOI: 10.1038/s41598-021-95858-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/07/2021] [Indexed: 02/06/2023] Open
Abstract
Total body upstream stimulatory factor 1 (USF1) deficiency in mice is associated with brown adipose tissue activation and a marked protection against the development of obesity and atherosclerotic lesions. Functional expression of USF1 has also been detected in monocytes and monocyte-derived macrophages. In the current study we therefore tested whether selective hematopoietic USF1 deficiency can also beneficially impact the development of atherosclerosis. For this purpose, LDL receptor knockout mice were transplanted with bone marrow from USF1 knockout mice or their wild-type littermate controls and subsequently fed a Western-type diet for 20 weeks to stimulate atherosclerotic lesion development. Strikingly, absence of USF1 function in bone marrow-derived cells was associated with exacerbated blood leukocyte (+ 100%; P < 0.01) and peritoneal leukocyte (+ 50%; P < 0.05) lipid loading and an increased atherosclerosis susceptibility (+ 31%; P < 0.05). These effects could be attributed to aggravated hyperlipidemia, i.e. higher plasma free cholesterol (+ 33%; P < 0.001) and cholesteryl esters (+ 39%; P < 0.001), and the development of hepatosteatosis. In conclusion, we have shown that hematopoietic USF1 deficiency is associated with an increased atherosclerosis susceptibility in LDL receptor knockout mice. These findings argue against a contribution of macrophage-specific USF1 deficiency to the previously described beneficial effect of total body USF1 deficiency on atherosclerosis susceptibility in mice.
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Affiliation(s)
- Menno Hoekstra
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
| | - Baoyan Ren
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Pirkka-Pekka Laurila
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland.,Genomics and Biobank Unit, National Institute for Health and Welfare, Biomedicum 1, Helsinki, Finland.,Institute for Molecular Medicine Finland, FIMM, Helsinki, Finland
| | - Reeni B Hildebrand
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Jarkko Soronen
- Genomics and Biobank Unit, National Institute for Health and Welfare, Biomedicum 1, Helsinki, Finland.,Pharmaceuticals Division, Bayer Oy BOF-PH-MRA-MA, Medical Affairs PO, Espoo, Finland
| | - Vanessa Frodermann
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Zhuang Li
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mariëtte R Boon
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Janine J Geerling
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Patrick C N Rensen
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland
| | - Miranda Van Eck
- Gorlaeus Laboratories, Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
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2
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Liu Y, Nonnemacher MR, Alexaki A, Pirrone V, Banerjee A, Li L, Kilareski E, Wigdahl B. Functional Studies of CCAAT/Enhancer Binding Protein Site Located Downstream of the Transcriptional Start Site. Clin Med Insights Pathol 2017; 10:1179555717694556. [PMID: 29162980 PMCID: PMC5692137 DOI: 10.1177/1179555717694556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/20/2016] [Indexed: 12/13/2022] Open
Abstract
Previous studies have identified a CCAAT/enhancer binding protein (C/EBP) site located downstream of the transcriptional start site (DS3). The role of the DS3 element with respect to HIV-1 transactivation by Tat and viral replication has not been characterized. We have demonstrated that DS3 was a functional C/EBPβ binding site and mutation of this site to the C/EBP knockout DS3-9C variant showed lower HIV-1 long terminal repeat (LTR) transactivation by C/EBPβ. However, it was able to exhibit similar or even higher transcription levels by Tat compared to the parental LTR. C/EBPβ and Tat together further enhanced the transcription level of the parental LAI-LTR and DS3-9C LTR, with higher levels in the DS3-9C LTR. HIV molecular clone viruses carrying the DS3-9C variant LTR demonstrated a decreased replication capacity and delayed rate of replication. These results suggest that DS3 plays a role in virus transcriptional initiation and provides new insight into C/EBP regulation of HIV-1.
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Affiliation(s)
- Yujie Liu
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Aikaterini Alexaki
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Vanessa Pirrone
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Anupam Banerjee
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Luna Li
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Evelyn Kilareski
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.,Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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3
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Regulation of C/EBPβ and resulting functions in cells of the monocytic lineage. Cell Signal 2012; 24:1287-96. [DOI: 10.1016/j.cellsig.2012.02.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 02/14/2012] [Indexed: 01/10/2023]
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4
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Soldati C, Bithell A, Conforti P, Cattaneo E, Buckley NJ. Rescue of gene expression by modified REST decoy oligonucleotides in a cellular model of Huntington's disease. J Neurochem 2010; 116:415-25. [PMID: 21105876 DOI: 10.1111/j.1471-4159.2010.07122.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Transcriptional dysfunction is a prominent hallmark of Huntington's disease (HD). Several transcription factors have been implicated in the aetiology of HD progression and one of the most prominent is repressor element 1 (RE1) silencing transcription factor (REST). REST is a global repressor of neuronal gene expression and in the presence of mutant Huntingtin increased nuclear REST levels lead to elevated RE1 occupancy and a concomitant increase in target gene repression, including brain-derived neurotrophic factor. It is of great interest to devise strategies to reverse transcriptional dysregulation caused by increased nuclear REST and determine the consequences in HD. Thus far, such strategies have involved RNAi or mutant REST constructs. Decoys are double-stranded oligodeoxynucleotides corresponding to the DNA-binding element of a transcription factor and act to sequester it, thereby abrogating its transcriptional activity. Here, we report the use of a novel decoy strategy to rescue REST target gene expression in a cellular model of HD. We show that delivery of the decoy in cells expressing mutant Huntingtin leads to its specific interaction with REST, a reduction in REST occupancy of RE1s and rescue of target gene expression, including Bdnf. These data point to an alternative strategy for rebalancing the transcriptional dysregulation in HD.
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Affiliation(s)
- Chiara Soldati
- Department of Neuroscience and Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, The James Black Centre, London, UK
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5
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Liu Y, Nonnemacher MR, Stauff DL, Li L, Banerjee A, Irish B, Kilareski E, Rajagopalan N, Suchitra JB, Khan ZK, Ranga U, Wigdahl B. Structural and functional studies of CCAAT/enhancer binding sites within the human immunodeficiency virus type 1 subtype C LTR. Biomed Pharmacother 2010; 64:672-80. [PMID: 20970301 DOI: 10.1016/j.biopha.2010.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/05/2010] [Indexed: 11/17/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) subtype C, which is most predominant in sub-Saharan Africa as well as in Asia and India, is the most prevalent subtype worldwide. A large number of transcription factor families have been shown to be involved in regulating HIV-1 gene expression in T lymphocytes and cells of the monocyte-macrophage lineage. Among these, proteins of the CCAAT/enhancer binding protein (C/EBP) family are of particular importance in regulating HIV-1 gene expression within cells of the monocytic lineage during the course of hematologic development and cellular activation. Few studies have examined the role of C/EBPs in long terminal repeat (LTR)-directed viral gene expression of HIV-1 subtypes other than subtype B. Within subtype B viruses, two functional C/EBP sites located upstream of the TATA box are required for efficient viral replication in cells of the monocyte-macrophage lineage. We report the identification of three putative subtype C C/EBP sites, upstream site 1 and 2 (C-US1 and C-US2) and downstream site 1 (C-DS1). C-US1 and C-DS1 were shown to form specific DNA-protein complexes with members of the C/EBP family (C/EBPα, β, and δ). Functionally, within the U-937 monocytic cell line, subtype B and C LTRs were shown to be equally responsive to C/EBPβ-2, although the basal activity of subtype C LTRs appeared to be higher. Furthermore, the synergistic interaction between C/EBPβ-2 and Tat with the subtype C LTR was also observed in U-937 cells as previously demonstrated with the subtype B LTR.
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Affiliation(s)
- Yujie Liu
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
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6
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Herbein G, Varin A. The macrophage in HIV-1 infection: from activation to deactivation? Retrovirology 2010; 7:33. [PMID: 20380696 PMCID: PMC2859752 DOI: 10.1186/1742-4690-7-33] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 04/09/2010] [Indexed: 01/09/2023] Open
Abstract
Macrophages play a crucial role in innate and adaptative immunity in response to microorganisms and are an important cellular target during HIV-1 infection. Recently, the heterogeneity of the macrophage population has been highlighted. Classically activated or type 1 macrophages (M1) induced in particular by IFN-γ display a pro-inflammatory profile. The alternatively activated or type 2 macrophages (M2) induced by Th-2 cytokines, such as IL-4 and IL-13 express anti-inflammatory and tissue repair properties. Finally IL-10 has been described as the prototypic cytokine involved in the deactivation of macrophages (dM). Since the capacity of macrophages to support productive HIV-1 infection is known to be modulated by cytokines, this review shows how modulation of macrophage activation by cytokines impacts the capacity to support productive HIV-1 infection. Based on the activation status of macrophages we propose a model starting with M1 classically activated macrophages with accelerated formation of viral reservoirs in a context of Th1 and proinflammatory cytokines. Then IL-4/IL-13 alternatively activated M2 macrophages will enter into the game that will stop the expansion of the HIV-1 reservoir. Finally IL-10 deactivation of macrophages will lead to immune failure observed at the very late stages of the HIV-1 disease.
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Affiliation(s)
- Georges Herbein
- Department of Virology, UPRES EA 4266 Pathogens and Inflammation, IFR 133 INSERM, Franche-Comte University, CHU Besançon, Besançon, France.
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7
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Gudmundsdottir I, Risatti GR. Infection of porcine alveolar macrophages with recombinant chimeric porcine reproductive and respiratory syndrome virus: effects on cellular gene transcription and virus growth. Virus Res 2009; 145:145-50. [PMID: 19540286 DOI: 10.1016/j.virusres.2009.06.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/29/2009] [Accepted: 06/03/2009] [Indexed: 12/28/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) genetic determinants affecting the response of the host primary target cell, the macrophage, to infection are yet to be defined. Here we have used recombinant viruses encompassing ORF 1A to identify PRRSV determinants associated with growth and modulation of pro- and anti-inflammatory cytokine expression in primary pulmonary alveolar macrophages (PAMs) cultures. Three genomic chimeras encompassing ORF 1A of PRRSV live attenuated vaccine Prime Pac (LAV SP) in the genetic background of pathogenic strain NVSL 97-7895 (FL12v) were characterized in vitro. Unlike parental viruses, two of the recombinant viruses encompassing the area of the genome encoding for NSP2 to NSP8 showed reduced growth in PAM cultures. The effect of virus infections on gene activation was studied for 25 immunomodulatory cellular genes in PAMs at 24 and 48h post-infection (hpi). Steady state mRNA levels in PAMs infected with recombinant and LAV SP viruses were compared to levels observed in cells infected with parental virus FL12v. Recombinant viruses induced patterns of transcriptional activation differing from patterns induced by parental FL12v, suggesting a regulatory role of PRRSV ORF1A on PAM gene expression.
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Affiliation(s)
- Ingigerdur Gudmundsdottir
- Department of Pathobiology and Veterinary Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269-3089, USA
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8
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Liu Y, Nonnemacher MR, Wigdahl B. CCAAT/enhancer-binding proteins and the pathogenesis of retrovirus infection. Future Microbiol 2009; 4:299-321. [PMID: 19327116 DOI: 10.2217/fmb.09.4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Previous studies indicate that two upstream CCAAT/enhancer-binding protein (C/EBP) sites and C/EBPbeta are required for subtype B HIV-1 gene expression in cells of the monocyte-macrophage lineage. The mechanisms of C/EBP regulation of HIV-1 transcription and replication remain unclear. This review focuses on studies concerning the role of C/EBP factors in HIV-1, human T-cell leukemia virus type 1, and SIV transcription in various cell types and tissues cultured in vitro, animal models and during human infection. The structure and function of the C/EBPbeta gene and the related protein isoforms are discussed along with the transcription factors, coactivators, viral proteins, cytokines and chemokines that affect C/EBP function.
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Affiliation(s)
- Yujie Liu
- Department of Microbiology & Immunology, Center for Molecular Virology & Neuroimmunology, Center for Cancer Biology, Philadelphia, PA 19129, USA
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9
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Saksena S, Dwivedi A, Gill RK, Singla A, Alrefai WA, Malakooti J, Ramaswamy K, Dudeja PK. PKC-dependent stimulation of the human MCT1 promoter involves transcription factor AP2. Am J Physiol Gastrointest Liver Physiol 2009; 296:G275-83. [PMID: 19033536 PMCID: PMC2643915 DOI: 10.1152/ajpgi.90503.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Monocarboxylate transporter (MCT1) plays an important role in the absorption of short-chain fatty acids (SCFA) such as butyrate in the human colon. Previous studies from our laboratory have demonstrated that phorbol ester, PMA (1 microM, 24 h), upregulates butyrate transport and MCT1 protein expression in human intestinal Caco-2 cells. However, the molecular mechanisms involved in the transcriptional regulation of MCT1 gene expression by PMA in the intestine are not known. In the present study, we showed that PMA (0.1 microM, 24 h) increased the MCT1 promoter activity (-871/+91) by approximately fourfold. A corresponding increase in MCT1 mRNA abundance in response to PMA was also observed. PMA-induced stimulation of MCT1 promoter activity was observed as early as 1 h and persisted until 24 h, suggesting that the effects of PMA are attributable to initial PKC activation. Kinase inhibitor and phosphorylation studies indicated that these effects may be mediated through activation of the atypical PKC-zeta isoform. 5'-deletion studies demonstrated that the MCT1 core promoter region (-229/+91) is the PMA-responsive region. Site-directed mutagenesis studies showed the predominant involvement of potential activator protein 2 (AP2) binding site in the activation of MCT1 promoter activity by PMA. In addition, overexpression of AP2 in Caco-2 cells significantly increased MCT1 promoter activity in a dose-dependent manner. These findings showing the regulation of MCT1 promoter by PKC and AP2 are of significant importance for an understanding of the molecular regulation of SCFA absorption in the human intestine.
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Affiliation(s)
- Seema Saksena
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Alka Dwivedi
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ravinder K. Gill
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Amika Singla
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Waddah A. Alrefai
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Jaleh Malakooti
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Krishnamurthy Ramaswamy
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pradeep K. Dudeja
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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10
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Pares-Matos EI, Milligan JS, Bina M. Exploring Transcription Factor Binding Properties of Several Non-coding DNA Sequence Elements in the Human NF-IL6 Gene. J Mol Biol 2006; 357:732-47. [PMID: 16458921 DOI: 10.1016/j.jmb.2005.12.071] [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] [Received: 11/15/2005] [Revised: 12/19/2005] [Accepted: 12/21/2005] [Indexed: 12/18/2022]
Abstract
We examined several DNA segments upstream of the transcription start site of the human NF-IL6 gene to evaluate the predictions of two computational models developed to identify potential regulatory elements in the non-coding regions of genes. One model, comparative genomics, is based on the hypothesis that functional regulatory sequences can be localized in alignments of genomic DNA from several species. The other model is based on the hypothesis that protein-binding sites in genomic DNA may include sequence elements that occur frequently in proximal promoters of genes. The segments selected for DNA binding and functional evaluations included: (1) two conserved regions identified in multi-species sequence alignments; (2) a region containing several localized hits with 9-mers that ranked highly in studies of proximal promoters of human genes; and (3) two regions that were either GC-rich and/or contained tracts of G. The assays were done under nearly identical experimental conditions, using a cell line (U937) representing human monocytes/macrophages. The experiments also aimed at evaluating what effect, if any, cellular stimulation could have on the interactions of nuclear proteins with naturally occurring GC-rich elements in a human genomic DNA. In DNA binding assays, several complexes were formed with the conserved regions identified in multi-species sequence alignment. Furthermore, these regions were active in functional assays. The region containing several matches with 9-mers derived from proximal promoters of human genes was not conserved but formed several complexes with nuclear proteins including Sp1, Egr-1, and an unidentified protein. In addition, this region was active in functional assays and responded to cellular stimulations. Overall, the results of the assays suggest an important role for the sequence context of genomic DNA in protein binding and selection.
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11
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Ramírez de Arellano E, Soriano V, Holguín A. [Regulation of transcription in different HIV-1 subtypes]. Enferm Infecc Microbiol Clin 2005; 23:156-62. [PMID: 15757588 DOI: 10.1157/13072166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transcriptional activation of HIV-1 gene expression is controlled in part by the interaction of viral and cellular transcription factors with the HIV-1 long terminal repeat (LTR) sequences. LTR variability among different HIV-1 subtypes could affect LTR binding of either cellular or viral elements, influencing the transcription level. This effect, in turn, may have consequences on the biology of the different HIV-1 clades and on disease progression. In some circumstances, a relationship between replication capacity in vitro and changes in binding sequences for transcription factors located at the LTR has been proven.
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Affiliation(s)
- Eva Ramírez de Arellano
- Laboratorio de Biología Molecular, Servicio de Enfermedades Infecciosas, Hospital Carlos III, Madrid, Spain
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12
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Osiecki K, Xie L, Zheng JH, Squires R, Pettoello-Mantovani M, Goldstein H. Identification of granulocyte-macrophage colony-stimulating factor and lipopolysaccharide-induced signal transduction pathways that synergize to stimulate HIV type 1 production by monocytes from HIV type 1 transgenic mice. AIDS Res Hum Retroviruses 2005; 21:125-39. [PMID: 15725751 DOI: 10.1089/aid.2005.21.125] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
HIV-1-infected monocyte/macrophages located in lymph nodes and tissues are highly productive sources of HIV-1 and may function as a persistent reservoir contributing to the rebound viremia observed after highly active antiretroviral therapy is stopped. Mechanisms activating latently infected, primary monocyte/macrophages to produce HIV-1 were investigated using monocytes isolated from a transgenic mouse line carrying a full-length proviral clone of a monocyte-tropic HIV-1 isolate, HIV-1(JR-CSF), regulated by the endogenous long terminal repeat (LTR) (JR-CSF mice). Granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with lipopolysaccharide (LPS) induced infectious HIV-1 production by JR-CSF mouse monocytes over 10-fold and 100-fold higher than that stimulated by GM-CSF or LPS alone, respectively. We examined mechanisms of GM-CSF synergy with LPS and demonstrated that GM-CSF up-regulated the LPS receptor, TLR-4, and also synergized with LPS to activate mitogen-activated protein (MAP) kinase/ERK kinase and the Sp1 transcription factor. Inhibitors of either MAP kinase/ERK kinase or p38 kinase but not PI 3-kinase potently suppressed GM-CSF and LPS-induced HIV-1 production by JR-CSF mouse monocytes. Because Sp1 is activated by both the MAP kinase/ERK kinase and p38 kinase pathways, we postulate that synergistic activation of these pathways by GM-CSF and LPS induced sufficient levels of Sp1 to activate the HIV-1 LTR in a Tat-independent manner and induced HIV-1 production by JR-CSF mouse monocytes. Thus, our study delineated the pathway of HIV-1 LTR activation by GM-CSF and LPS and indicated that JR-CSF transgenic mice may provide a new in vitro and in vivo system for investigating the mechanism by which inflammatory and infectious stimuli activate HIV-1 production from latently infected monocytes.
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Affiliation(s)
- Kristin Osiecki
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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13
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Lee ES, Kalantari P, Tsutsui Section S, Klatt A, Holden J, Correll PH, Power Section C, Henderson AJ. RON Receptor Tyrosine Kinase, a Negative Regulator of Inflammation, Inhibits HIV-1 Transcription in Monocytes/Macrophages and Is Decreased in Brain Tissue from Patients with AIDS. THE JOURNAL OF IMMUNOLOGY 2004; 173:6864-72. [PMID: 15557181 DOI: 10.4049/jimmunol.173.11.6864] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of macrophages and microglia cells after HIV-1 infection and their production of inflammatory mediators contribute to HIV-associated CNS diseases. The mechanisms that initiate and maintain inflammation after HIV-1 infection in the brain have not been well studied. Furthermore, it is not understood why in HIV-associated CNS disease, macrophages and microglia are biased toward inflammation rather than production of mediators that control inflammation. We have focused on the receptor tyrosine kinase RON, a critical negative regulator of macrophage function and inflammation, to determine whether this receptor regulates HIV-1 expression. Overexpressing RON in monocytes/macrophages demonstrates that RON inhibits HIV-1 proviral transcription in part by decreasing the binding activity of NF-kappaB to the HIV-1 long terminal repeat. Because macrophages and microglia cells are a critical reservoir for HIV-1 in the CNS, we examined brain tissues for RON expression and detected RON in astrocytes, cortical neurons, and monocytoid cells. RON was detected in all control patients who were HIV seronegative (n = 7), whereas six of nine brain samples obtained from AIDS patients exhibited reduced RON protein. These data suggest that RON initiates signaling pathways that negatively regulate HIV-1 transcription in monocytes/macrophages and that HIV-1 suppresses RON function by decreasing protein levels in the brain to assure efficient replication. Furthermore, HIV-1 infection would compromise the ability of RON to protect against inflammation and consequent CNS damage.
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Affiliation(s)
- Eileen S Lee
- Graduate Program in Biochemistry, Department of Veterinary Science, Pennsylvania State University, University Park, PA 16802, USA
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14
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Abstract
To examine the mechanism of HIV-1 regulation by NF-IL6 in activated human cells, we selected a Jurkat cell line that did not contain endogenous NF-IL6. In this cellular environment, we evaluated the effect of exogenous NF-IL6 on transcription mediated by native and deleted LTR sequences. In Jurkat cells stimulated with LPS and PMA, LTR-mediated transcription was enhanced by NF-IL6. The results of deletion studies revealed a central role for the basal LTR region and the TATA element in the LTR, in upregulation of reporter gene expression by NF-IL6 in activated cells. In the selected cellular environment, regulation of transcription by NF-IL6 was not evident in studies of promoter regions of other genes. The results implied that the basal region of HIV-1 LTR includes molecular properties that support activation of HIV-1 by NF-IL6 in stimulated cells.
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Affiliation(s)
- Anissa E Buckner
- Department of Chemistry, Purdue University, 1393 Brown Building, W. Lafayette, IN 47907, USA
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15
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Yang Y, Pares-Matos EI, Tesmer VM, Dai C, Ashworth S, Huai J, Bina M. Organization of the promoter region of the human NF-IL6 gene. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1577:102-8. [PMID: 12151100 DOI: 10.1016/s0167-4781(02)00401-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In monocyte/macrophages, the human NF-IL6 gene was activated by LPS or PMA. However, a robust response required stimulation of cells with both LPS and PMA. To examine the molecular basis of this response, we isolated human genomic DNA and determined the nucleotide sequence of a segment (6.4 kb) that included the transcription initiation site of the gene. The unique sequences in the 6.4-kb DNA include several potential transcription factor-binding elements that may explain the molecular basis of the activation of the human NF-IL6 gene by signaling molecules that control the immune and inflammatory responses. Deletion analysis localized an LPS+PMA responsive region downstream position -287, with respect to the transcription initiation site of the NF-IL6 gene. The responsive region includes a potential site for interactions with CREB and a region (-287 to -247) that interacts with SP1 and SP3. In functional assays, the potential CREB site responded to cellular stimulation. The region that interacted with SP1 and SP3 augmented the overall level of activity produced in response to LPS+PMA.
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Affiliation(s)
- Yingmei Yang
- Department of Chemistry, Purdue University, 1393 Brown Building, West Lafayette, IN 47907-1393, USA
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