Hexamethylbisacetamide Remodels the Human Immunodeficiency Virus Type 1 (HIV-1) Promoter and Induces Tat-Independent HIV-1 Expression but Blunts Cell Activation

ABSTRACT Hexamethylbisacetamide (HMBA) induces human immunodeficiency virus type 1 (HIV-1) gene expression in latently infected T-cell and monocytoid cell lines. We find that HMBA activation of viral expression is Tat independent but, like Tat, increases the efficiency of elongation of the HIV-1 promoter (long terminal repeat [LTR]) transcripts. Further, exposure to HMBA induces chromatin remodeling at nucleosome 1 (Nuc-1) near the start site of LTR transcription but does so without increasing histone acetylation or altering histone methylation near Nuc-1. Of note, despite enhanced proviral expression, HMBA suppressed HIV infection ex vivo in primary blood mononuclear cell (PBMC) cultures. Treatment with HMBA did not alter expression of the HIV coreceptors, CCR5 and CXCR4, in PBMCs but down-regulated CD4. Finally, HMBA interferes with cell proliferation and activation; it suppressed expression of Ki67 and CD25 and in PBMCs exposed to mitogen. As HMBA has been tested in oncology trials, its unusual properties make it a useful reagent for future studies of HIV promoter regulation and a novel prototype molecule for therapeutics that abort the latent proviral state of chronic HIV infection.

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

Cells ◽

10.3390/cells10071798 ◽

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.

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CCR5- and CXCR4-Tropic Subtype C Human Immunodeficiency Virus Type 1 Isolates Have a Lower Level of Pathogenic Fitness than Other Dominant Group M Subtypes: Implications for the Epidemic

Journal of Virology ◽

10.1128/jvi.02051-08 ◽

2009 ◽

Vol 83 (11) ◽

pp. 5592-5605 ◽

Cited By ~ 63

Author(s):

Awet Abraha ◽

Immaculate L. Nankya ◽

Richard Gibson ◽

Korey Demers ◽

Denis M. Tebit ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Ex Vivo ◽

Sub Saharan Africa ◽

Subtype C ◽

Immunodeficiency Virus ◽

Subtype A ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) subtype C is the dominant subtype globally, due largely to the incidence of subtype C infections in sub-Saharan Africa and east Asia. We compared the relative replicative fitness (ex vivo) of the major (M) group of HIV-1 subtypes A, B, C, D, and CRF01_AE and group O isolates. To estimate pathogenic fitness, pairwise competitions were performed between CCR5-tropic (R5) or CXCR4-tropic (X4) virus isolates in peripheral blood mononuclear cells (PBMC). A general fitness order was observed among 33 HIV-1 isolates; subtype B and D HIV-1 isolates were slightly more fit than the subtype A and dramatically more fit than the 12 subtype C isolates. All group M isolates were more fit (ex vivo) than the group O isolates. To estimate ex vivo transmission fitness, a subset of primary HIV-1 isolates were examined in primary human explants from penile, cervical, and rectal tissues. Only R5 isolates and no X4 HIV-1 isolates could replicate in these tissues, whereas the spread to PM1 cells was dependent on active replication and passive virus transfer. In tissue competition experiments, subtype C isolates could compete with and, in some cases, even win over subtype A and D isolates. However, when the migratory cells from infected tissues were mixed with a susceptible cell line, the subtype C isolates were outcompeted by other subtypes, as observed in experiments with PBMC. These findings suggest that subtype C HIV-1 isolates might have equal transmission fitness but reduced pathogenic fitness relative to other group M HIV-1 isolates.

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Human Immunodeficiency Virus Type 1 Variants Resistant to First- and Second-Version Fusion Inhibitors and Cytopathic in Ex Vivo Human Lymphoid Tissue

Journal of Virology ◽

10.1128/jvi.02546-06 ◽

2007 ◽

Vol 81 (12) ◽

pp. 6563-6572 ◽

Cited By ~ 33

Author(s):

Raghavan Chinnadurai ◽

Devi Rajan ◽

Jan Münch ◽

Frank Kirchhoff

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Lymphoid Tissue ◽

Ex Vivo ◽

Fusion Inhibitors ◽

Immunodeficiency Virus ◽

Human Lymphoid Tissue ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) fusion inhibitors blocking viral entry by binding the gp41 heptad repeat 1 (HR1) region offer great promise for antiretroviral therapy, and the first of these inhibitors, T20 (Fuzeon; enfuvirtide), is successfully used in the clinic. It has been reported previously that changes in the 3-amino-acid GIV motif at positions 36 to 38 of gp41 HR1 mediate resistance to T20 but usually not to second-version fusion inhibitors, such as T1249, which target an overlapping but distinct region in HR1 including a conserved hydrophobic pocket (HP). Based on the common lack of cross-resistance and the difficulty of selecting T1249-resistant HIV-1 variants, it has been suggested that the determinants of resistance to first- and second-version fusion inhibitors may be different. To further assess HIV-1 resistance to fusion inhibitors and to analyze where changes in HR1 are tolerated, we randomized 16 codons in the HR1 region, including those making contact with HR2 codons and/or encoding residues in the GIV motif and the HP. We found that changes only at positions 37I, 38V, and 40Q near the N terminus of HR1 were tolerated. The propagation of randomly gp41-mutated HIV-1 variants in the presence of T1249 allowed the effective selection of highly resistant forms, all containing changes in the IV residues. Overall, the extent of T1249 resistance was inversely correlated to viral fitness and cytopathicity. Notably, one HIV-1 mutant showing ∼10-fold-reduced susceptibility to T1249 inhibition replicated with wild type-like kinetics and caused substantial CD4+-T-cell depletion in ex vivo-infected human lymphoid tissue in the presence and absence of an inhibitor. Taken together, our results show that the GIV motif also plays a key role in resistance to second-version fusion inhibitors and suggest that some resistant HIV-1 variants may be pathogenic in vivo.

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Human Immunodeficiency Virus Type 1 Latency Model for High-Throughput Screening

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.12.5185-5188.2005 ◽

2005 ◽

Vol 49 (12) ◽

pp. 5185-5188 ◽

Cited By ~ 16

Author(s):

Sofiya Micheva-Viteva ◽

Annmarie L. Pacchia ◽

Yacov Ron ◽

Stuart W. Peltz ◽

Joseph P. Dougherty

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

High Throughput ◽

High Throughput Screening ◽

Immunodeficiency Virus ◽

Latently Infected ◽

A Cell ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) is not eliminated from patients even after years of antiretroviral therapy, apparently due to the presence of latently infected cells. Here we describe the development of a cell-based system of latency that can be used for high-throughput screening aimed at novel drug discovery to eradicate HIV-1 infection.

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Topotecan inhibits human immunodeficiency virus type 1 infection through a topoisomerase-independent mechanism in a cell line with altered topoisomerase I.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.5.977 ◽

1997 ◽

Vol 41 (5) ◽

pp. 977-981 ◽

Cited By ~ 11

Author(s):

J L Zhang ◽

P L Sharma ◽

C J Li ◽

B J Dezube ◽

A B Pardee ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Cell Line ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Topoisomerase I ◽

Immunodeficiency Virus ◽

Latently Infected ◽

A Cell ◽

Hiv 1

Topotecan (TPT), a known inhibitor of topoisomerase I, has previously been shown to inhibit the replication of several viruses. The mechanism of inhibition was proposed to be the inhibition of topoisomerase I. We report that TPT decreased replication of human immunodeficiency virus type 1 (HIV-1) in CPT-K5, a cell line with a topoisomerase I mutation. TPT inhibited production of HIV-1 RNA and p24 in CPT-K5 and wild-type cells equally effectively. The antiviral effects of TPT were observed not only in the topoisomerase-mutated CPT-K5 line but also in peripheral blood mononuclear cells (PBMC) acutely infected with clinical isolates and in OM10.1 cells latently infected with HIV and activated by tumor necrosis factor alpha. Little toxicity from TPT was noted in HIV-1-infected PBMC and in CPT-K5 and OM10.1 cells as measured by cell growth and proliferation assays. These observations suggest that TPT targets factors in virus replication other than cellular topoisomerase I and inhibits cytokine-mediated activation in latently infected cells by means other than cytotoxicity. These results suggest a potential for TPT and for other camptothecins in anti-HIV therapy alone and in combination with other antiretroviral drugs.

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Proline 35 of Human Immunodeficiency Virus Type 1 (HIV-1) Vpr Regulates the Integrity of the N-Terminal Helix and the Incorporation of Vpr into Virus Particles and Supports the Replication of R5-Tropic HIV-1 in Human Lymphoid Tissue Ex Vivo

Journal of Virology ◽

10.1128/jvi.02803-06 ◽

2007 ◽

Vol 81 (17) ◽

pp. 9572-9576 ◽

Cited By ~ 6

Author(s):

Jörg Votteler ◽

Nicole Studtrucker ◽

Stefan Sörgel ◽

Jan Münch ◽

Elke Rücker ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Lymphoid Tissue ◽

Mutational Analysis ◽

Ex Vivo ◽

Immunodeficiency Virus ◽

Human Lymphoid Tissue ◽

Hiv 1

ABSTRACT Mutational analysis of the four conserved proline residues in human immunodeficiency virus type 1 (HIV-1) Vpr reveals that only Pro-35 is required for efficient replication of R5-tropic, but not of X4-tropic, viruses in human lymphoid tissue (HLT) cultivated ex vivo. While Vpr-mediated apoptosis and G2 cell cycle arrest, as well as the expression and subcellular localization of Vpr, were independent, the capacity for encapsidation of Vpr into budding virions was dependent on Pro-35. 1H nuclear magnetic resonance data suggest that mutation of Pro-35 causes a conformational change in the hydrophobic core of the molecule, whose integrity is required for the encapsidation of Vpr, and thus, Pro-35 supports the replication of R5-tropic HIV-1 in HLT.

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Characterization of Chemokine Receptor Utilization of Viruses in the Latent Reservoir for Human Immunodeficiency Virus Type 1

Journal of Virology ◽

10.1128/jvi.74.17.7824-7833.2000 ◽

2000 ◽

Vol 74 (17) ◽

pp. 7824-7833 ◽

Cited By ~ 115

Author(s):

Theodore Pierson ◽

Trevor L. Hoffman ◽

Joel Blankson ◽

Diana Finzi ◽

Karen Chadwick ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Chemokine Receptor ◽

Latent Reservoir ◽

Immunodeficiency Virus ◽

Latently Infected ◽

Hiv 1

ABSTRACT Latently infected resting CD4+ T cells provide a long-term reservoir for human immunodeficiency virus type 1 (HIV-1) and are likely to represent the major barrier to virus eradication in patients on combination antiretroviral therapy. The mechanisms by which viruses enter the latent reservoir and the nature of the chemokine receptors involved have not been determined. To evaluate the phenotype of the virus in this compartment with respect to chemokine receptor utilization, full-length HIV-1 env genes were cloned from latently infected cells and assayed functionally. We demonstrate that the majority of the viruses in the latent reservoir utilize CCR5 during entry, although utilization of several other receptors, including CXCR4, was observed. No alternative coreceptors were shown to be involved in a systematic fashion. Although R5 viruses are present in the latent reservoir, CCR5 was not expressed at high levels on resting CD4+ T cells. To understand the mechanism by which R5 viruses enter latent reservoir, the ability of an R5 virus, HIV-1 Ba-L, to infect highly purified resting CD4+ T lymphocytes from uninfected donors was evaluated. Entry of Ba-L could be observed when virus was applied at a multiplicity approaching 1. However, infection was limited to a subset of cells expressing low levels of CCR5 and markers of immunologic memory. Naive cells could not be infected by an R5 virus even when challenged with a large inoculum. Direct cell fractionation studies showed that latent virus is present predominantly in resting memory cells but also at lower levels in resting naive cells. Taken together, these findings provide support for the hypothesis that the direct infection of naive T cells is not the major mechanism by which the latent infection of resting T cells is established.

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New Synthetic Histone Deacetylase Inhibitors CGMC0005 and CGMC0006 Effectively Reactivate Latently Infected Human Immunodeficiency Virus Type-1 (HIV-1) from ACH2 and J1.1 CD4+ T Cells

Antiviral Research ◽

10.1016/j.antiviral.2008.01.077 ◽

2008 ◽

Vol 78 (2) ◽

pp. A40-A41

Author(s):

Kee-Jong Hong ◽

Sung-Soon Kim ◽

Hak Sung Lee ◽

Joo-Shil Lee ◽

Byeong-Sun Choi

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Histone Deacetylase ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Histone Deacetylase Inhibitors ◽

Immunodeficiency Virus ◽

Latently Infected ◽

Hiv 1

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Vpr and Vpu Are Important for Efficient Human Immunodeficiency Virus Type 1 Replication and CD4+ T-Cell Depletion in Human Lymphoid Tissue Ex Vivo

Journal of Virology ◽

10.1128/jvi.78.22.12689-12693.2004 ◽

2004 ◽

Vol 78 (22) ◽

pp. 12689-12693 ◽

Cited By ~ 33

Author(s):

Elke Rücker ◽

Jean-Charles Grivel ◽

Jan Münch ◽

Frank Kirchhoff ◽

Leonid Margolis

Keyword(s):

Human Immunodeficiency Virus ◽

T Cell ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Lymphoid Tissue ◽

Ex Vivo ◽

Immunodeficiency Virus ◽

Human Lymphoid Tissue ◽

Hiv 1

ABSTRACT The relevance of the accessory vpr, vpu, and nef genes for human immunodeficiency virus type 1 (HIV-1) replication in human lymphoid tissue (HLT), the major site of viral replication in vivo, is largely unknown. Here, we show that an individual deletion of nef, vpr, or vpu significantly decreases HIV-1 replication and prevents CD4+ T-cell depletion in ex vivo HLT. However, only combined defects in all three accessory genes entirely disrupt the replicative capacity of HIV-1. Our results demonstrate that nef, vpr, and vpu are all essential for efficient viral spread in HLT, suggesting an important role in AIDS pathogenesis.

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