Histone deacetylase–mediated transcriptional activation reduces proviral loads in HTLV-1–associated myelopathy/tropical spastic paraparesis patients

Blood ◽  
2007 ◽  
Vol 110 (10) ◽  
pp. 3722-3728 ◽  
Author(s):  
Agnès Lezin ◽  
Nicolas Gillet ◽  
Stéphane Olindo ◽  
Aïssatou Signaté ◽  
Nathalie Grandvaux ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Transcriptional Activation ◽  
Gene Activation ◽  
Spastic Paraparesis ◽  
Viral Gene Expression ◽  
Tropical Spastic Paraparesis ◽  
Viral Reservoir ◽  
Viral Gene

AbstractEpigenetic modifications of chromatin may play a role in maintaining viral latency and thus persistence of the human T-lymphotropic virus type 1 (HTLV-1), which is responsible for HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). A major determinant of disease progression is increased peripheral blood proviral load (PVL), possibly via the accumulation of infected cells in the central nervous system (CNS) creating a damaging inflammatory response. Current therapeutic approaches that focus on reducing either cell proliferation, viral replication, or tissue invasion are still unsatisfactory. Contrasting with these inhibitory strategies, we evaluated the efficacy of a novel approach aimed, paradoxically, at activating viral gene expression to expose virus-positive cells to the host immune response. We used valproate (VPA), a histone deacetylase inhibitor that has been used for decades as a chronic, safe treatment for epileptic disorders. Based on in vitro and in vivo data, we provide evidence that transient activation of the latent viral reservoir causes its collapse, a process that may alleviate the condition of HAM/TSP. This represents the first such approach to treating HAM/TSP, using gene activation therapy to tilt the host-pathogen balance in favor of an existing antiviral response. This trial is registered at http://clinicaltrials.gov/as no. NCT00519181.

scholarly journals β-adrenergic Receptor Stimulation Revealed a Novel Regulatory Pathway via Suppressing Histone Deacetylase 3 to Induce Uncoupling Protein 1 Expression in Mice Beige Adipocyte

2018 ◽  
Vol 19 (8) ◽  
pp. 2436 ◽  
Author(s):  
Ana Yuliana ◽  
Huei-Fen Jheng ◽  
Satoko Kawarasaki ◽  
Wataru Nomura ◽  
Haruya Takahashi ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Transcriptional Activation ◽  
Adrenergic Receptor ◽  
Uncoupling Protein ◽  
Open Chromatin ◽  
Uncoupling Protein 1 ◽  
Beige Adipocyte ◽  
Ucp1 Expression

Browning of adipose tissue has been prescribed as a potential way to treat obesity, marked by the upregulation of uncoupling protein 1 (Ucp1). Several reports have suggested that histone deacetylase (HDAC) might regulate Ucp1 by remodelling chromatin structure, although the mechanism remains unclear. Herein, we investigate the effect of β-adrenergic receptor (β-AR) activation on the chromatin state of beige adipocyte. β-AR-stimulated Ucp1 expression via cold (in vivo) and isoproterenol (in vitro) resulted in acetylation of histone activation mark H3K27. H3K27 acetylation was also seen within Ucp1 promoter upon isoproterenol addition, favouring open chromatin for Ucp1 transcriptional activation. This result was found to be associated with the downregulation of class I HDAC mRNA, particularly Hdac3 and Hdac8. Further investigation showed that although HDAC8 activity decreased, Ucp1 expression was not altered when HDAC8 was activated or inhibited. In contrast, HDAC3 mRNA and protein levels were simultaneously downregulated upon isoproterenol addition, resulting in reduced recruitment of HDAC3 to the Ucp1 enhancer region, causing an increased H3K27 acetylation for Ucp1 upregulation. The importance of HDAC3 inhibition was confirmed through the enhanced Ucp1 expression when the cells were treated with HDAC3 inhibitor. This study highlights the novel mechanism of HDAC3-regulated Ucp1 expression during β-AR stimulation.

scholarly journals Cell-to-Cell Contact as an Efficient Mode of Epstein-Barr Virus Infection of Diverse Human Epithelial Cells

1998 ◽  
Vol 72 (5) ◽  
pp. 4371-4378 ◽  
Author(s):  
Shosuke Imai ◽  
Jun Nishikawa ◽  
Kenzo Takada
Keyword(s):  
Epithelial Cells ◽  
Cell Lines ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Cell Contact ◽  
Barr Virus ◽  
Epithelial Cell Lines ◽  
Epstein Barr

ABSTRACT We show clear evidence for direct infection of various human epithelial cells by Epstein-Barr virus (EBV) in vitro. The successful infection was achieved by using recombinant EBV (Akata strain) carrying a selective marker gene but without any other artificial operations, such as introduction of the known EBV receptor (CD21) gene or addition of polymeric immunoglobulin A against viral gp350 in culture. Of 21 human epithelial cell lines examined, 18 became infected by EBV, as ascertained by the detection of EBV-determined nuclear antigen (EBNA) 1 expression in the early period after virus exposure, and the following selection culture easily yielded a number of EBV-infected clones from 15 cell lines. None of the human fibroblasts and five nonhuman-derived cell lines examined was susceptible to the infection. By comparison, cocultivation with virus producers showed ≈800-fold-higher efficiency of infection than cell-free infection did, suggesting the significance of direct cell-to-cell contact as a mode of virus spread in vivo. Most of the epithelial cell lines infectable with EBV were negative for CD21 expression at the protein and mRNA levels. The majority of EBV-infected clones established from each cell line invariably expressed EBNA1, EBV-encoded small RNAs, rightward transcripts from theBamHI-A region of the virus genome, and latent membrane protein (LMP) 2A, but not the other EBNAs or LMP1. This restricted form of latent viral gene expression, which is a central issue for understanding epithelial oncogenesis by EBV, resembled that seen in EBV-associated gastric carcinoma and LMP1-negative nasopharyngeal carcinoma. The results indicate that direct infection of epithelial cells by EBV may occur naturally in vivo, and this could be mediated by an unidentified, epithelium-specific binding receptor for EBV. The EBV convertants are viewed, at least in terms of viral gene expression, as in vitro analogs of EBV-associated epithelial tumor cells, thus facilitating analysis of an oncogenic role(s) for EBV in epithelial cells.

scholarly journals HTLV-1 Rex is required for viral spread and persistence in vivo but is dispensable for cellular immortalization in vitro

Blood ◽  
2003 ◽  
Vol 102 (12) ◽  
pp. 3963-3969 ◽  
Author(s):  
Jianxin Ye ◽  
Lee Silverman ◽  
Michael D. Lairmore ◽  
Patrick L. Green
Keyword(s):  
Gene Expression ◽  
Interleukin 2 ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Viral Oncoprotein ◽  
Cell Leukemia Virus Type ◽  
Viral Spread ◽  
Human T Cell

Abstract Human T-cell leukemia virus type 1 (HTLV-1) is associated with leukemia/lymphoma and neurologic disorders. Although the viral transcriptional activator Tax is the critical viral oncoprotein, Rex, which regulates the expression of the viral structural and enzymatic genes, is essential for efficient viral replication. Herein, we investigate the contribution of Rex in HTLV-1 immortalization of primary T cells in vitro and viral survival in an infectious rabbit animal model. A Rex-deficient HTLV-1 (HTLVRex-) was constructed and characterized for viral gene expression, protein production, and immortalization capacity. Cells transiently transfected with the HTLVRex- proviral clone produced low detectable levels of p19 Gag. 729HTLVRex- stable transfectants produced functional Tax, but undetectable levels of Rex or p19 Gag. Coculture of irradiated 729HTLVRex- cells with peripheral blood mononuclear cells (PBMCs) resulted in sustained interleukin-2 (IL-2)-dependent growth of primary T lymphocytes. These cells carried the HTLVRex- genome and expressed tax/rex mRNA but produced no detectable Rex or p19 Gag. Rabbits inoculated with irradiated 729HTLVRex- cells or 729HTLVRex- cells transiently transfected with a Rex cDNA expression plasmid failed to become persistently infected or mount a detectable antibody response to the viral gene products. Together, our results provide the first direct evidence that Rex and its function to modulate viral gene expression and virion production is not required for in vitro immortalization by HTLV-1. However, Rex is critical for efficient infection of cells and persistence in vivo.

scholarly journals Rat Cytomegalovirus Gene Expression in Cardiac Allograft Recipients Is Tissue Specific and Does Not Parallel the Profiles Detected In Vitro

2007 ◽  
Vol 81 (8) ◽  
pp. 3816-3826 ◽  
Author(s):  
Daniel N. Streblow ◽  
Koen W. R. van Cleef ◽  
Craig N. Kreklywich ◽  
Christine Meyer ◽  
Patricia Smith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rat Heart ◽  
Cultured Cells ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Viral Mrna ◽  
Tissue Specific ◽  
Viral Genes

ABSTRACT Rat cytomegalovirus (RCMV) is a β-herpesvirus with a 230-kbp genome containing over 167 open reading frames (ORFs). RCMV gene expression is tightly regulated in cultured cells, occurring in three distinct kinetic classes (immediate early, early, and late). However, the extent of viral-gene expression in vivo and its relationship to the in vitro expression are unknown. In this study, we used RCMV-specific DNA microarrays to investigate the viral transcriptional profiles in cultured, RCMV-infected endothelial cells, fibroblasts, and aortic smooth muscle cells and to compare these profiles to those found in tissues from RCMV-infected rat heart transplant recipients. In cultured cells, RCMV expresses approximately 95% of the known viral ORFs with few differences between cell types. By contrast, in vivo viral-gene expression in tissues from rat heart allograft recipients is highly restricted. In the tissues studied, a total of 80 viral genes expressing levels twice above background (5,000 to 10,000 copies per μg total RNA) were detected. In each tissue type, there were a number of genes expressed exclusively in that tissue. Although viral mRNA and genomic DNA levels were lower in the spleen than in submandibular glands, the number of individual viral genes expressed was higher in the spleen (60 versus 41). This finding suggests that the number of viral genes expressed is specific to a given tissue and is not dependent upon the viral load or viral mRNA levels. Our results demonstrate that the profiles, as well as the amplitude, of viral-gene expression are tissue specific and are dramatically different from those in infected cultured cells, indicating that RCMV gene expression in vitro does not reflect viral-gene expression in vivo.

scholarly journals In Vivo Requirement of Activator-Specific Binding Targets of Mediator

2000 ◽  
Vol 20 (23) ◽  
pp. 8709-8719 ◽  
Author(s):  
Jin Mo Park ◽  
Hye-Suk Kim ◽  
Sang Jun Han ◽  
Moon-Sun Hwang ◽  
Young Chul Lee ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Specific Binding ◽  
Gene Activation ◽  
Dna Interaction ◽  
Activation Process ◽  
Binding Region ◽  
Physiological Conditions ◽  
Functional Analyses

ABSTRACT There has been no unequivocal demonstration that the activator binding targets identified in vitro play a key role in transcriptional activation in vivo. To examine whether activator-Mediator interactions are required for gene transcription under physiological conditions, we performed functional analyses with Mediator components that interact specifically with natural yeast activators. Different activators interact with Mediator via distinct binding targets. Deletion of a distinct activator binding region of Mediator completely compromised gene activation in vivo by some, but not all, transcriptional activators. These demonstrate that the activator-specific targets in Mediator are essential for transcriptional activation in living cells, but their requirement was affected by the nature of the activator-DNA interaction and the existence of a postrecruitment activation process.

scholarly journals Over-representation of MEF-2 isoforms (A/C) is associated with HTLV-1-induced acute ATLL and their recruitment to 3’LTR facilitates HBZ expression from the antisense promoter via interactions with Menin and Jun D

2021 ◽  
Author(s):  
Kiran Madugula ◽  
Julie Joseph ◽  
Vanessa Teixeira ◽  
Rashida Ginwala ◽  
Catherine Demarino ◽  
...  
Keyword(s):  
T Cell ◽  
Transcriptional Control ◽  
Treatment Options ◽  
Viral Gene Expression ◽  
Etiologic Agent ◽  
Antisense Strand ◽  
Viral Gene ◽  
Adult T Cell Leukemia

Abstract Background. HTLV-1 is a complex human retrovirus and an etiologic agent causing a malignant and intractable T-cell neoplasia termed Adult T-cell leukemia and lymphoma (ATLL). Patients suffering from ATLL present with poor prognoses and a dearth of treatment options warranting a continuous need to develop novel therapeutic targets. In contrast to the HTLV-1 transactivator protein Tax, HTLV-1 bZIP protein (HBZ) maintains its expression in ATLL cells. The HBZ gene is encoded from the antisense strand of the provirus and is not under the transcriptional control of the 5’ long terminal repeat (LTR) unlike other viral genes such as Tax. Few modifications have been reported in the 3’LTR, which regulates HBZ expression. Herein, we delineate the activities of a transcription factor MEF (Myocyte enhancer factor)-2 at both 5’ and 3’LTRs in the context of ATLL progression and maintenance. Results. In this study, we report that two MEF isoforms (2A and 2C) are highly overexpressed in acute ATLL patients from North America. These isoforms are recruited to the viral promoters at both the 5’ and 3’LTRs. Their knockdown by shRNAs resulted in the downregulation of Tax and HBZ expression as well as a significant decrease in proliferation and cell cycle arrest in ATLL cells. Similarly, chemical inhibition of MEF proteins by MC1568 (a selective Class IIa HDAC inhibitor) resulted in the cytotoxicity of ATLL cells in vitro as well as reduction of proviral load and viral gene expression in vivo. At the molecular level, high enrichment of MEF-2C occurred at the 3’LTR along with cofactors Menin, Jun D, and Sp1/Sp3 thus providing a novel mechanism of regulation at the antisense promoter of HTLV-1. Conclusions. This study establishes MEF-2 as critical players in ATLL, which interacts with Tax and HBZ at their respective promoters highlighting a novel mechanism of regulation at the 3’LTR involving Jun D and Menin. MEF signaling represent a potential target for therapeutic intervention.

258 MESSENGER RNA EXPRESSION PATTERNS OF HISTONE MODIFICATION GENES IN BOVINE EMBRYOS DERIVED FROM DIFFERENT ORIGINS

2006 ◽  
Vol 18 (2) ◽  
pp. 236 ◽  
Author(s):  
M. Nowak-Imialek ◽  
C. Wrenzycki ◽  
D. Herrmann ◽  
I. Lagutina ◽  
A. Lucas-Hahn ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Relative Abundance ◽  
Transcriptional Activation ◽  
Messenger Rna ◽  
Expression Patterns ◽  
Rna Expression ◽  
Bovine Embryos ◽  
Different Origins

Epigenetic modifications of the genome, such as covalent modifications of histones, are crucial for transcriptional regulation during development. The N-terminal tails of the histones are subject to post-translational modifications, including acetylation, deacetylation and methylation. histone acetylation loosens chromatin packing and correlates with transcriptional activation. The enzymes Histone acetyltransferases (HATs) transfer acetyl moieties to the lysine residues of histones H2A, H2B, H3, and H4. Histone acetylation is a reversible process which is catalyzed by the histone deacetylase (HDAC) and results in transcriptional repression. Histone methyltransferase (HMT) is responsible for the methylation of arginine in histones 3 and 4, playing an important role in transcriptional activation of genes. In contrast, the H3 Lys 9 methylation is associated with a transcriptionally repressive heterochromatin. The objective of the present study was to determine the effects of different origins of embryos on the relative abundance of transcripts for the histone acetyltransferase 1 (HAT1), histone deacetylase 2 (HDAC2), histone metyltransferases (SUV39H1 and G9A), and heterochromatin protein 1 (HP1). Messenger RNA expression profiles of these genes were investigated in bovine oocytes and pre-implantation embryos up to the blastocyt stage produced either in vitro by two different culture systems, i.e. SOF+BSA or TCM+SERUM, by somatic cloning using adult male and female fibroblasts, parthenogenetic activation, and androgenetic construction, or in vivo, employing semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Significant differences are described below. HAT1, SUV39H1, G9A, and HP1 mRNA transcripts decreased in enucleated oocytes, compared with immature oocytes. The relative abundance of HAT1 and SUV39H1 transcripts was significantly increased in NT-derived zygotes produced from adult female fibroblasts, compared to their in vitro fertilized and parthenogenetic counterparts. No differences were found in the relative abundances of gene transcripts at the 8-16-cell stage, except for parthenogenetic embryos in which SUV39H1 transcripts were significantly higher than in all other 8-16 cell groups. The relative abundance of SUV39H1, G9A, and HP1 transcripts were significantly higher in NT-derived blastocysts derived from adult male fibroblasts than in their in vivo-generated counterparts. HP1 and G9A transcript levels were significantly increased in NT-derived blastocysts derived from male fibroblasts compared to NT-derived embryos produced from female fibroblasts. The results show that the in vitro environment and the nuclear transfer protocol affect mRNA expression patterns of histone modification genes in pre-implantation bovine embryos.

A discrete element 3' of human immunodeficiency virus 1 (HIV-1) and HIV-2 mRNA initiation sites mediates transcriptional activation by an HIV trans activator

1988 ◽  
Vol 8 (6) ◽  
pp. 2555-2561
Author(s):  
A Jakobovits ◽  
D H Smith ◽  
E B Jakobovits ◽  
D J Capon
Keyword(s):  
Transcriptional Activation ◽  
Mutational Analysis ◽  
Regulatory Element ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Translational Efficiency ◽  
Mrna Accumulation ◽  
Enhancer Activity ◽  
Hiv 1

An important point of regulation in the reproductive growth and latency of the human and simian immunodeficiency viruses (HIV and SIV, respectively) is provided by virally encoded trans-activators (tat), proteins capable of dramatically increasing viral gene expression. The mechanism of this autostimulatory pathway has remained unclear, however, with substantial effects having been reported at the level of either mRNA accumulation, translational efficiency, or both. Our previous findings indicated that trans-activation results primarily from induction of RNA levels but could not distinguish between the roles of transcriptional rate, RNA stabilization, and RNA transport in this event. In addition, the boundaries of tat-responding elements, which would be valuable in elucidating the mode of tat action, are not precisely known. In this study, HIV-1 and HIV-2 long terminal repeat-directed expression was characterized by using an in vitro nuclear transcription assay to clarify this mechanism, and a detailed mutational analysis was undertaken to localize precisely the sequences participating in this process. Two key findings were revealed: an increased transcription rate was the primary event in tat-mediated activation of HIV-1 and HIV-2, and trans-activation was impaired by mutations in two regions, the TATA box and sequences between +19 to +42, a region lacking enhancer activity. These results implicate a discrete 3' regulatory element in the transcriptional activation of the HIVs.

Butyrate induces selective transcriptional activation of a hypomethylated embryonic globin gene in adult erythroid cells

Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1536-1542
Author(s):  
LJ Burns ◽  
JG Glauber ◽  
GD Ginder
Keyword(s):  
Sodium Butyrate ◽  
Transcriptional Activation ◽  
Globin Gene ◽  
Gene Activation ◽  
Globin Genes ◽  
Erythroid Cells ◽  
Hemoglobin Switching ◽  
High Level

An animal model of hemoglobin switching has been developed in which anemic adult chickens are treated with 5-azacytidine and sodium butyrate or alpha-aminobutyric acid, thereby resulting in activation of the embryonic rho-globin gene in adult erythroid cells. In vitro nuclear runoff transcription assays using erythroid nuclei from treated birds show that the mechanism of activation of the rho-globin gene is transcriptional whereas no transcriptional activation of the embryonic epsilon-globin gene occurs. The action of 5-azacytidine appears to be as an inhibitor of DNA methylation because other S-phase active cytotoxic drugs, when substituted for 5-azacytidine, do not cause demethylation of the embryonic globin genes, nor do they allow transcriptional activation to occur. Embryonic rho-globin gene activation in this model is not due to selection of primitive erythroid cells since a subpopulation of primitive erythroid cells is not evident either morphologically or when cells are probed for embryonic and adult globin RNA by in situ hybridization. These studies show that demethylation by 5-azacytidine is a prerequisite but not sufficient cis- regulatory event for a high level of transcriptional activation of the embryonic rho-globin gene in adult erythroid cells in vivo. The possible basis for the selective transcriptional activation by sodium butyrate in this system is discussed.

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