scholarly journals Inhibition of Replication of Reactivated Human Immunodeficiency Virus Type 1 (HIV-1) in Latently Infected U1 Cells Transduced with an HIV-1 Long Terminal Repeat-Driven PKR cDNA Construct

1999 ◽  
Vol 73 (11) ◽  
pp. 9021-9028 ◽  
Author(s):  
Nicholas F. Muto ◽  
Camille Martinand-Mari ◽  
Martin E. Adelson ◽  
Robert J. Suhadolnik
Keyword(s):  
Human Immunodeficiency Virus ◽  
Long Terminal Repeat ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Terminal Repeat ◽  
Tnf Α ◽  
Immunodeficiency Virus ◽  
Latently Infected ◽  
Hiv 1

ABSTRACT Treatment of human immunodeficiency virus type 1 (HIV-1)-infected individuals with highly active antiretroviral therapy has effectively decreased viral load to undetectable levels. However, efforts to eliminate HIV-1 from these individuals have been unsuccessful, due to the presence of stable, latent viral reservoirs in resting and active CD4+ T lymphocytes and macrophages. These latent populations have become critical targets in the effort to eradicate HIV-1 from infected individuals. The mechanisms of HIV-1 latency have been studied by using the HIV-1-infected promonocytic cell line U1. The interferon-inducible double-stranded RNA-dependent p68 protein kinase (PKR), a key enzyme in the host-mediated antiviral response, is known to be down-regulated during HIV-1 infection. Therefore, in order to evaluate the role of PKR in the inhibition of replication of reactivated HIV-1 in latently infected U1 cells, we have utilized cDNA constructs containing PKR under the transcriptional control of the HIV-1 long terminal repeat. One PKR-transduced clone, U1/106-4:27, inhibited the tumor necrosis factor alpha (TNF-α)-induced replication of HIV-1 by 99% compared to control U1 cells as measured by syncytium formation and HIV-1 p24 antigen enzyme-linked immunosorbent assay. Western blot analysis showed an increase in PKR expression through 96 h postinduction in the U1/106-4:27 clone, concomitant with maximal increases in phosphorylation of the α subunit of eukaryotic initiation factor 2 and NF-κB activity at 72 h postinduction. These results demonstrate that overexpression of PKR can inhibit the replication of reactivated HIV-1 in latently infected cells and confirm the involvement of PKR in the interferon-associated antiviral pathway against HIV-1 infection. Additionally, treatment of the PKR-transduced U1/106-4:27 clone with the protease inhibitor saquinavir (250 nM) completely inhibited TNF-α-induced HIV-1 replication.

scholarly journals The Human Factors YY1 and LSF Repress the Human Immunodeficiency Virus Type 1 Long Terminal Repeat via Recruitment of Histone Deacetylase 1

2000 ◽  
Vol 74 (15) ◽  
pp. 6790-6799 ◽  
Author(s):  
Jason J. Coull ◽  
Fabio Romerio ◽  
Jian-Min Sun ◽  
Janet L. Volker ◽  
Katherine M. Galvin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Long Terminal Repeat ◽  
Histone Deacetylase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Zinc Fingers ◽  
Terminal Repeat ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Enigmatic mechanisms restore the resting state in activated lymphocytes following human immunodeficiency virus type 1 (HIV-1) infection, rarely allowing persistent nonproductive infection. We detail a mechanism whereby cellular factors could establish virological latency. The transcription factors YY1 and LSF cooperate in repression of transcription from the HIV-1 long terminal repeat (LTR). LSF recruits YY1 to the LTR via the zinc fingers of YY1. The first two zinc fingers were observed to be sufficient for this interaction in vitro. A mutant of LSF incapable of binding DNA blocked repression. Like other transcriptional repressors, YY1 can function via recruitment of histone deacetylase (HDAC). We find that HDAC1 copurifies with the LTR-binding YY1-LSF repressor complex, the domain of YY1 that interacts with HDAC1 is required to repress the HIV-1 promoter, expression of HDAC1 augments repression of the LTR by YY1, and the deacetylase inhibitor trichostatin A blocks repression mediated by YY1. This novel link between HDAC recruitment and inhibition of HIV-1 expression by YY1 and LSF, in the natural context of a viral promoter integrated into chromosomal DNA, is the first demonstration of a molecular mechanism of repression of HIV-1. YY1 and LSF may establish transcriptional and virological latency of HIV, a state that has recently been recognized in vivo and has significant implications for the long-term treatment of AIDS.

scholarly journals Inhibition of Human Immunodeficiency Virus Type 1 Replication in Latently Infected Cells by a Novel IκB Kinase Inhibitor

2006 ◽  
Vol 50 (2) ◽  
pp. 547-555 ◽  
Author(s):  
Ann Florence B. Victoriano ◽  
Kaori Asamitsu ◽  
Yurina Hibi ◽  
Kenichi Imai ◽  
Nina G. Barzaga ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Iκb Kinase ◽  
Tnf Α ◽  
Immunodeficiency Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT In human immunodeficiency virus type 1 (HIV-1) latently infected cells, NF-κB plays a major role in the transcriptional induction of HIV-1 replication. Hence, downregulation of NF-κB activation has long been sought for effective anti-HIV therapy. Tumor necrosis factor alpha (TNF-α) stimulates IκB kinase (IKK) complex, a critical regulator in the NF-κB signaling pathway. A novel IKK inhibitor, ACHP {2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-piperidin-4-yl-nicotinonitrile}, was developed and evaluated as a potent and specific inhibitor for IKK-α and IKK-β. In this study, we examined the ability of this compound to inhibit HIV-1 replication in OM10.1 cells latently infected with HIV. When these cells were pretreated with ACHP, TNF-α-induced HIV-1 replication was dramatically inhibited, as measured by the HIV p24 antigen levels in the culture supernatants. Its 50% effective concentration was approximately 0.56 μM, whereas its 50% cytotoxic concentration was about 15 μM. Western blot analysis revealed inhibition of IκBα phosphorylation, IκBα degradation, p65 nuclear translocation, and p65 phosphorylation. ACHP was also found to suppress HIV-1 long terminal repeat (LTR)-driven gene expression through the inhibition of NF-κB activation. Furthermore, ACHP inhibited TNF-α-induced NF-κB (p65) recruitment to the HIV-1 LTR, as assessed by chromatin immunoprecipitation assay. These findings suggest that ACHP acts as a potent suppressor of TNF-α-induced HIV replication in latently infected cells and that this inhibition is mediated through suppression of IKK activity.

scholarly journals Cross-Interaction between JC Virus Agnoprotein and Human Immunodeficiency Virus Type 1 (HIV-1) Tat Modulates Transcription of the HIV-1 Long Terminal Repeat in Glial Cells

2006 ◽  
Vol 80 (18) ◽  
pp. 9288-9299 ◽  
Author(s):  
Dorota Kaniowska ◽  
Rafal Kaminski ◽  
Shohreh Amini ◽  
Sujatha Radhakrishnan ◽  
Jay Rappaport ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Long Terminal Repeat ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Jc Virus ◽  
Terminal Repeat ◽  
Human Astrocytes ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human polyomavirus JC virus (JCV) is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), which is commonly seen in AIDS patients. The bicistronic viral RNA, which is transcribed at the late phase of infection, is responsible for expressing the viral capsid proteins and a small regulatory protein, agnoprotein. Immunohistochemical analysis of brain tissue from subjects with AIDS/PML revealed colocalization of the human immunodeficiency virus type 1 (HIV-1) transactivator, Tat, and JCV agnoprotein in nucleus and cytoplasm of “bizarre” astrocytes. In accord with this observation, we detected the copresence of agnoprotein and Tat in human astrocytes upon infection with JCV and HIV-1 or in astrocytic cells expressing these proteins after transfection. Interestingly, results from infection of human astrocytes with HIV-1 and JCV showed a decrease in the level of HIV-1 replication in cells that are coinfected with JCV. Conversely, a slight increase in the level of JCV replication was observed in the presence of HIV-1. The copresence of JCV and HIV-1 in astrocytes prompted us to investigate the possible cross-interaction of agnoprotein with Tat and its impact on HIV-1 gene transcription. Our results demonstrate that agnoprotein through its N-terminal domain associates with Tat and the interaction causes the suppression of Tat-mediated enhancement of HIV-1 promoter activity in these cells. Results from RNA and protein binding assays showed that agnoprotein can inhibit the association of Tat with its target RNA sequence, TAR, and with cyclin T1. Furthermore, agnoprotein is able to interfere with cross-interaction of Tat with the p65 subunit of NF-κB and Sp1, whose functions are critical for Tat activation of the long terminal repeat. These observations unravel a new pathway for the molecular interaction of these two viruses in biologically relevant cells in the brains of AIDS/PML patients.

scholarly journals IRF-1 Is Required for Full NF-κB Transcriptional Activity at the Human Immunodeficiency Virus Type 1 Long Terminal Repeat Enhancer

2008 ◽  
Vol 82 (7) ◽  
pp. 3632-3641 ◽  
Author(s):  
Marco Sgarbanti ◽  
Anna L. Remoli ◽  
Giulia Marsili ◽  
Barbara Ridolfi ◽  
Alessandra Borsetti ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Long Terminal Repeat ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Transcriptional Activity ◽  
Terminal Repeat ◽  
Viral Transactivator ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) gene expression is controlled by a complex interplay between viral and host factors. We have previously shown that interferon-regulatory factor 1 (IRF-1) is stimulated early after HIV-1 infection and regulates promoter transcriptional activity even in the absence of the viral transactivator Tat. In this work we demonstrate that IRF-1 is also required for full NF-κB transcriptional activity. We provide evidence that IRF-1 and NF-κB form a functional complex at the long terminal repeat (LTR) κB sites, which is abolished by specific mutations in the two adjacent κB sites in the enhancer region. Silencing IRF-1 with small interfering RNA resulted in impaired NF-κB-mediated transcriptional activity and in repressed HIV-1 transcription early in de novo-infected T cells. These data indicate that in early phases of HIV-1 infection or during virus reactivation from latency, when the viral transactivator is absent or present at very low levels, IRF-1 is an additional component of the p50/p65 heterodimer binding the LTR enhancer, absolutely required for efficient HIV-1 replication.

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