scholarly journals Targeting Epigenetics to Cure HIV-1: Lessons From (and for) Cancer Treatment

2021 ◽  
Vol 11 ◽  
Author(s):  
J. Peter Svensson
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cancer Treatment ◽  
Chromatin Structure ◽  
Cd4 Cells ◽  
Functional Cure ◽  
Transcription Control ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Single Promoter

The Human Immunodeficiency Virus type 1 (HIV-1) integrates in the host genome as a provirus resulting in a long-lived reservoir of infected CD4 cells. As a provirus, HIV-1 has several aspects in common with an oncogene. Both the HIV-1 provirus and oncogenes only cause disease when expressed. A successful cure of both cancer and HIV-1 includes elimination of all cells with potential to regenerate the disease. For over two decades, epigenetic drugs developed against cancer have been used in the HIV-1 field to modulate the state of the proviral chromatin. Cells with an intact HIV-1 provirus exist in three states of infection: productive, inducible latent, and non-inducible latent. Here focus is on HIV-1, transcription control and chromatin structure; how the inducible proviruses are maintained in a chromatin structure that allows reactivation of transcription; and how transcription switches between different stages to allow for an abundance of different transcripts from a single promoter. Recently it was shown that a functional cure of HIV can be achieved by encapsulating all intact HIV-1 proviruses in heterochromatin, giving hope that epigenetic interventions may be used to end the HIV-1 epidemic.

scholarly journals Induction of Autophagy to Achieve a Human Immunodeficiency Virus Type 1 Cure

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1798
Author(s):  
Grant R. Campbell ◽  
Stephen A. Spector
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Functional Cure ◽  
Immunodeficiency Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

Effective antiretroviral therapy has led to significant human immunodeficiency virus type 1 (HIV-1) suppression and improvement in immune function. However, the persistence of integrated proviral DNA in latently infected reservoir cells, which drive viral rebound post-interruption of antiretroviral therapy, remains the major roadblock to a cure. Therefore, the targeted elimination or permanent silencing of this latently infected reservoir is a major focus of HIV-1 research. The most studied approach in the development of a cure is the activation of HIV-1 expression to expose latently infected cells for immune clearance while inducing HIV-1 cytotoxicity—the “kick and kill” approach. However, the complex and highly heterogeneous nature of the latent reservoir, combined with the failure of clinical trials to reduce the reservoir size casts doubt on the feasibility of this approach. This concern that total elimination of HIV-1 from the body may not be possible has led to increased emphasis on a “functional cure” where the virus remains but is unable to reactivate which presents the challenge of permanently silencing transcription of HIV-1 for prolonged drug-free remission—a “block and lock” approach. In this review, we discuss the interaction of HIV-1 and autophagy, and the exploitation of autophagy to kill selectively HIV-1 latently infected cells as part of a cure strategy. The cure strategy proposed has the advantage of significantly decreasing the size of the HIV-1 reservoir that can contribute to a functional cure and when optimised has the potential to eradicate completely HIV-1.

scholarly journals Transcriptional Activation of the Integrated Chromatin-Associated Human Immunodeficiency Virus Type 1 Promoter

1998 ◽  
Vol 18 (5) ◽  
pp. 2535-2544 ◽  
Author(s):  
Aboubaker El Kharroubi ◽  
Graziella Piras ◽  
Ralf Zensen ◽  
Malcolm A. Martin
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Chromatin Structure ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Core Promoter ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The regulation of human immunodeficiency virus type 1 (HIV-1) gene expression involves a complex interplay between cellular transcription factors, chromatin-associated proviral DNA, and the virus-encoded transactivator protein, Tat. Here we show that Tat transactivates the integrated HIV-1 long terminal repeat (LTR), even in the absence of detectable basal promoter activity, and this transcriptional activation is accompanied by chromatin remodeling downstream of the transcription initiation site, as monitored by increased accessibility to restriction endonucleases. However, with an integrated promoter lacking both Sp1 and NF-κB sites, Tat was unable to either activate transcription or induce changes in chromatin structure even when it was tethered to the HIV-1 core promoter upstream of the TATA box. Tat responsiveness was observed only when Sp1 or NF-κB was bound to the promoter, implying that Tat functions subsequent to the formation of a specific transcription initiation complex. Unlike Tat, NF-κB failed to stimulate the integrated transcriptionally silent HIV-1 promoter. Histone acetylation renders the inactive HIV-1 LTR responsive to NF-κB, indicating that a suppressive chromatin structure must be remodeled prior to transcriptional activation by NF-κB. Taken together, these results suggest that Sp1 and NF-κB are required for the assembly of transcriptional complexes on the integrated viral promoter exhibiting a continuum of basal activities, all of which are fully responsive to Tat.

scholarly journals A novel cellular RNA helicase, RH116, differentially regulates cell growth, programmed cell death and human immunodeficiency virus type 1 replication

2003 ◽  
Vol 84 (12) ◽  
pp. 3215-3225 ◽  
Author(s):  
C. Cocude ◽  
M.-J. Truong ◽  
O. Billaut-Mulot ◽  
V. Delsart ◽  
E. Darcissac ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Death ◽  
Cell Growth ◽  
Programmed Cell Death ◽  
Human Immunodeficiency Virus Type ◽  
Rna Helicase ◽  
Cd4 Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

In an effort to define novel cellular factors regulating human immunodeficiency virus type 1 (HIV-1) replication, a differential display analysis has been performed on endogenously infected cells stimulated with the HIV-suppressive immunomodulator Murabutide. In this study, the cloning and identification of a Murabutide-downregulated gene, named RH116, bearing classical motifs that are characteristic of the DExH family of RNA helicases, are reported. The 116 kDa encoded protein shares 99·9 % similarity with MDA-5, an inducible RNA helicase described recently. Ectopic expression of RH116 in HeLa-CD4 cells inhibited cell growth and cell proliferation but had no measurable effect on programmed cell death. RH116 presented steady state cytoplasmic localization and could translocate to the nucleus following HIV-1 infection. Moreover, the endogenous expression of RH116, at both the transcript and protein levels, was found to be considerably upregulated after infection. Overexpression of RH116 in HIV-1-infected HeLa-CD4 cells also resulted in a dramatic increase in the level of secreted viral p24 protein. This enhancement in virus replication did not stem from upregulated proviral DNA levels but correlated with increased unspliced and singly spliced viral mRNA transcripts. These findings implicate RH116 in the regulation of HIV-1 replication and point to an apoptosis-independent role for this novel helicase in inducing cell growth arrest.

scholarly journals Human Immunodeficiency Virus Type 1 Attachment to HeLa CD4 Cells Is CD4 Independent and gp120 Dependent and Requires Cell Surface Heparans

1998 ◽  
Vol 72 (5) ◽  
pp. 3623-3634 ◽  
Author(s):  
Isabelle Mondor ◽  
Sophie Ugolini ◽  
Quentin J. Sattentau
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Hela Cells ◽  
Target Cells ◽  
Cd4 Cells ◽  
Virus Binding ◽  
Hla Dr ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The binding of human immunodeficiency virus type 1 (HIV-1) (Hx10) virions to two different cell lines was analyzed by using a novel assay based on the detection, by anti-HLA-DR-specific antibodies, of HLA-DR+ virus binding to HLA-DR− cells. Virion attachment to the CD4+-T-cell line A3.01 was highly CD4 dependent in that it was potently inhibited by CD4 monoclonal antibodies (MAbs), and little virus binding to the CD4−sister A2.01 line was observed. By contrast, virion binding to HeLa cells expressing moderate or high levels of CD4 was equivalent to, or lower than, binding to wild-type CD4− HeLa cells. Moreover, several CD4 MAbs did not reduce, but enhanced, HIV-1 attachment to HeLa-CD4 cells. CD4 was required for infection of HeLa cells, however, demonstrating a postattachment role for this receptor. MAbs specific for the V2 and V3 loops and the CD4i epitope of gp120 strongly inhibited virion binding to HeLa-CD4 cells, whereas MAbs specific for the CD4bs and the 2G12 epitopes enhanced attachment. Despite this, all gp120- and gp41-specific MAbs tested neutralized infectivity on HeLa-CD4 cells. HIV-1 attachment to HeLa cells was only partially inhibited by MAbs specific for adhesion molecules present on the virus or target cells but was completely blocked by polyanions such as heparin, dextran sulfate, and pentosan sulfate. Treatment of HeLa-CD4 cells with heparinases completely eliminated HIV attachment and infection, strongly implicating cell surface heparans in the attachment process. CD4 dependence for HIV-1 attachment to target cells is thus highly cell line specific and may be replaced by other ligand-receptor interactions.

Involvement of long terminal repeat U3 sequences overlapping the transcription control region in human immunodeficiency virus type 1 mRNA 3' end formation

1991 ◽  
Vol 11 (3) ◽  
pp. 1624-1630
Author(s):  
J D DeZazzo ◽  
J E Kilpatrick ◽  
M J Imperiale
Keyword(s):  
Human Immunodeficiency Virus ◽  
Control Region ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Transcription Control ◽  
S1 Nuclease ◽  
Immunodeficiency Virus ◽  
A Site ◽  
Hiv 1

In retroviral proviruses, the poly(A) site is present in both long terminal repeats (LTRs) but used only in the 3' position. One mechanism to account for this selective poly(A) site usage is that LTR U3 sequences, transcribed only from the 3' poly(A) site, are required in the RNA for efficient processing. To test this possibility, mutations were made in the human immunodeficiency virus type 1 (HIV-1) U3 region and the mutated LTRs were inserted into simple and complex transcription units. HIV-1 poly(A) site usage was then quantitated by S1 nuclease analysis following transfection of each construct into human 293 cells. The results showed that U3 sequences confined to the transcription control region were required for efficient usage of the HIV-1 poly(A) site, even when it was placed 1.5 kb from the promoter. Although the roles of U3 in processing and transcription activation were separable, optimal 3' end formation was partly dependent on HIV-1 enhancer and SP1 binding site sequences.

scholarly journals cis-acting sequences located downstream of the human immunodeficiency virus type 1 promoter affect its chromatin structure and transcriptional activity.

1996 ◽  
Vol 16 (6) ◽  
pp. 2958-2966 ◽  
Author(s):  
A el Kharroubi ◽  
M A Martin
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Chromatin Structure ◽  
Transcriptional Activity ◽  
Regulatory Sequences ◽  
Immunodeficiency Virus ◽  
Basal Transcriptional Activity ◽  
Hiv 1

We have examined the roles of AP-1, AP-3-like, DBF1, and Sp1 binding sites, which are located downstream of the human immunodeficiency virus type 1 (HIV-1) promoter, in regulating basal transcriptional activity directed by the integrated viral long terminal repeat (LTR). Point mutations affecting all four of these elements functionally inactivated the HIV-1 LTR when it was constrained in a chromatin configuration. Analyses of the chromatin structures of the transcriptionally active wild-type and inactive mutated HIV-1 promoters revealed several differences. In the active promoter, the 3' half of the U3 region, including the basal promoter, the enhancer, and the putative upstream regulatory sequences are situated within a nuclease-hypersensitive region. However, the far upstream U3 region appears to be packaged into a nuclease-resistant nucleosomal structure, whereas the R, U5, and gag leader sequences are associated with a region of altered chromatin that is sensitive to restriction endonucleases. In the inactive template, only the basal promoter and enhancer element remain sensitive to nucleases, and the adjacent upstream and downstream regions are incorporated into nuclease-resistant nucleosomal structures. Taken together, these results indicate that the chromatin structure of the integrated HIV-1 LTR plays a critical role in modulating basal transcriptional activity.

scholarly journals Expression of the Human Immunodeficiency Virus Type-1 Coreceptors CXCR-4 (fusin, LESTR) and CKR-5 in CD34+ Hematopoietic Progenitor Cells

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3522-3528 ◽  
Author(s):  
Martin Deichmann ◽  
Ralf Kronenwett ◽  
Rainer Haas
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Progenitor Cells ◽  
Hematopoietic Progenitor Cells ◽  
Cd4 Cells ◽  
Hematopoietic Progenitor ◽  
Cd34 Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

Abstract CD34+ hematopoietic progenitor cells were assessed for mRNA expression of the human immunodeficiency virus type-1 (HIV-1) coreceptors CXCR-4, also termed fusin or LESTR, and CKR-5, also called CC-CKR-5 or CCR-5. The CD34+ cells were obtained from leukapheresis products of 17 patients after granulocyte colony-stimulating factor–supported cytotoxic chemotherapy. Using a two-step enrichment procedure including immunomagnetic bead separation and fluorescence-activated cell sorting, the CD34+ cells had a median purity of 99.8%. Assessing 9 CD34+ cell samples by polymerase chain reaction after reverse transcription (RT-PCR), CXCR-4 mRNA was found in all samples, whereas CKR-5 mRNA was only present in 3 samples, even though a nested PCR was used. Eight additional CD34+ cell samples were sorted according to CD4 expression. Based on a three-color immunofluorescence analysis, the mean relative fluorescence intensity of HLA-DR was smaller on CD34+/CD4+ cells in comparison with CD34+/CD4− cells. CXCR-4 mRNA was found in 5 of 8 CD34+/CD4+ samples and in 7 of 8 CD34+/CD4− samples, whereas CKR-5 mRNA was detected in 2 CD34+/CD4+ samples and in 1 CD34+/CD4− cell sample. Looking at the total number of CD34+ cell samples examined, the proportion of specimens containing CXCR-4 mRNA was 84% in comparison with 24% of specimens positive for CKR-5 mRNA. These data suggest that CD34+/CD4+ hematopoietic progenitor cells, including true stem cell candidates, could be susceptible to HIV-1 infection. Considering the relatively low incidence of CD34+ cell samples containing CKR-5 mRNA, CD34+/CD4+ cells appear to be particularly prone for HIV-1 infection via the CXCR-4 coreceptor. Because this chemokine receptor allows T-cell–tropic HIV-1 strains to infect cells, CD34+ cells expressing CD4 and CXCR-4 might be infected by HIV-1 during later stages of the disease, following a viral phenotype switch from macrophage- to T-cell–tropic HIV-1 strains.

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