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Arumugam T, Ramphal U, Adimulam T, Chinniah R, Ramsuran V. Deciphering DNA Methylation in HIV Infection. Front Immunol 2021; 12:795121. [PMID: 34925380 PMCID: PMC8674454 DOI: 10.3389/fimmu.2021.795121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022] Open
Abstract
With approximately 38 million people living with HIV/AIDS globally, and a further 1.5 million new global infections per year, it is imperative that we advance our understanding of all factors contributing to HIV infection. While most studies have focused on the influence of host genetic factors on HIV pathogenesis, epigenetic factors are gaining attention. Epigenetics involves alterations in gene expression without altering the DNA sequence. DNA methylation is a critical epigenetic mechanism that influences both viral and host factors. This review has five focal points, which examines (i) fluctuations in the expression of methylation modifying factors upon HIV infection (ii) the effect of DNA methylation on HIV viral genes and (iii) host genome (iv) inferences from other infectious and non-communicable diseases, we provide a list of HIV-associated host genes that are regulated by methylation in other disease models (v) the potential of DNA methylation as an epi-therapeutic strategy and biomarker. DNA methylation has also been shown to serve as a robust therapeutic strategy and precision medicine biomarker against diseases such as cancer and autoimmune conditions. Despite new drugs being discovered for HIV, drug resistance is a problem in high disease burden settings such as Sub-Saharan Africa. Furthermore, genetic therapies that are under investigation are irreversible and may have off target effects. Alternative therapies that are nongenetic are essential. In this review, we discuss the potential role of DNA methylation as a novel therapeutic intervention against HIV.
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Affiliation(s)
- Thilona Arumugam
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Upasana Ramphal
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine & Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Theolan Adimulam
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Romona Chinniah
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Veron Ramsuran
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine & Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
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Abstract
Diverse enveloped viruses enter cells by endocytosis and fusion with intracellular compartments. Recent evidence suggests that HIV also infects permissive cell lines by fusing with endosomes in a pH-independent manner. This finding highlights the importance of time-resolved monitoring of viral uptake. In the present study, we designed an imaging-based assay to measure endocytosis in real-time through probing the virus' accessibility to external solutions. Exposure of viruses bearing a pH-sensitive GFP (green fluorescent protein) variant on their surface to solutions of different acidity altered the fluorescence of surface-accessible particles, but not internalized viruses. By sequentially applying acidic and alkaline buffers with or without ammonium chloride, we were able to quantify the fractions of internalized and non-internalized virions, as well as the fraction of detached particles, over time. The exact time of single-virus internalization was assessed from the point when a particle ceased to respond to a perfusion with alternating acidic and alkaline buffers. We found that, surprisingly, HIV pseudoparticles entered acidic compartments shortly after internalization. These results suggest that the virus might be sorted to a quickly maturing pool of endocytic vesicles and thus be trafficked to fusion-permissive sites near the cell nucleus.
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Anzinger JJ, Olinger GG, Spear GT. Donor variability in HIV binding to peripheral blood mononuclear cells. Virol J 2008; 5:95. [PMID: 18706090 PMCID: PMC2538508 DOI: 10.1186/1743-422x-5-95] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 08/15/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV infection of cells varies greatly between individuals, with multiple steps in the replication cycle potentially contributing to the variability. Although entry and post-entry variability of HIV infection levels in cells has been demonstrated, variability in HIV binding has not been examined. In this study, we examined variability of HIV binding to peripheral blood mononuclear cells (PBMC) from different donors. RESULTS HIV binding to PBMC varied up to 3.9-fold between individuals and was independent of CD4. Replication of HIV in donor PBMC required CD4 and paralleled virus binding trends of donor PBMC. To assess the stability of virus binding phenotypes over time, HIV was bound to donors with low- and high-binding phenotypes. The binding phenotypes were maintained when tested weekly over a 4-week period for 3 of 4 donors, while one high-binding donor decreased to lower binding on the 4th week. The low- and high-binding phenotypes were also preserved across different HIV strains. Experiments performed to determine if there was an association between HIV binding levels and specific cell subset levels within PBMC showed no correlation, suggesting that HIV binds to multiple cell subsets. CONCLUSION These results show that differences exist in HIV binding to donor PBMC. Our data also show that HIV binding to donor PBMC is CD4-independent and can change over time, suggesting that virus binding variability is due to differences in the expression of changeable cell-surface host factors. Taken together, this study highlights the impact of cell-surface factors in HIV binding to, and infection of, PBMC which likely represents an important step in HIV infection in vivo.
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Affiliation(s)
- Joshua J Anzinger
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 5N111, Bethesda, Maryland 20892, USA.
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Garrido M, Mozos A, Martínez A, García F, Serafín A, Morente V, Caballero M, Gil C, Fumero E, Miró JM, Climent N, Gatell JM, Alos L. HIV-1 upregulates intercellular adhesion molecule-1 gene expression in lymphoid tissue of patients with chronic HIV-1 infection. J Acquir Immune Defic Syndr 2008; 46:268-74. [PMID: 17786132 DOI: 10.1097/qai.0b013e318142c74c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Intercellular adhesion molecule (ICAM)-1 is an adhesion molecule that plays an important role in the transmission of HIV-1 to CD4+ target cells and in the decrease of these cells in lymphoid tissue (LT). Our main objective was to study ICAM-1 expression in LT from HIV-1-infected persons and to correlate this expression with LT viral load and the immunoarchitecture alteration before and after highly active antiretroviral therapy (HAART). METHODS Tonsillar LT samples from 16 patients with chronic asymptomatic HIV-1 infection were studied before initiating treatment and after 12 months of HAART. ICAM-1 protein expression was studied by immunohistochemistry in all cases, and ICAM-1 messenger RNA (mRNA) was quantified from frozen tissue in 6 patients using quantitative real-time polymerase chain reaction (PCR). LT viral load was determined by PCR. The LT immunoarchitecture, p24 immunoexpression, and CD4+ cell count were assessed from tissue sections. RESULTS Before initiating HAART, there was high immunohistochemical ICAM-1 expression in follicular dendritic and endothelial cells and high ICAM-1 mRNA quantification. These findings correlated with a high LT viral load, strong p24 expression, and an effacement of LT immunoarchitecture with a low number of CD4+ cells. After HAART, there was a significant decrease of immunohistochemical and gene ICAM-1 expression. These results correlated with a significant decrease of LT viral load and p24 immunoexpression, a recovery of LT architecture, and a significant increase of CD4+ cells. CONCLUSIONS HIV-1 upregulates ICAM-1 expression in LT. This finding is associated with a marked effacement of LT architecture. HAART produces downregulation of ICAM-1 expression and recovery of LT architecture by reducing LT viral load significantly.
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Affiliation(s)
- Marta Garrido
- Department of Pathology, Hospital Clínic, Institut d'Investigacions Biomédiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain
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Haim H, Steiner I, Panet A. Time frames for neutralization during the human immunodeficiency virus type 1 entry phase, as monitored in synchronously infected cell cultures. J Virol 2007; 81:3525-34. [PMID: 17251303 PMCID: PMC1866073 DOI: 10.1128/jvi.02293-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Characterization of the neutralizing interaction between antibody and virus is hindered by the nonsynchronized progression of infection in cell cultures. Discrete steps of the viral entry sequence cannot be discerned, and thus, the mode of antibody-mediated interference with virus infectivity remains undefined. Here, we magnetically synchronize the motion and cell attachment of human immunodeficiency virus type 1 (HIV-1) to monitor the progression of neutralization, both in solution and following virus attachment to the cell. By simultaneous transfer of all viral particles from reaction solution with antibody to the cell-bound state, the precise rate of neutralization of cell-free virus could be determined for each antibody. HIV-1 neutralization by both monoclonal and polyclonal antibody preparations followed distinct pseudo-first-order kinetics. For all antibodies, cell types, and HIV-1 strains examined, postattachment interference served a major role in the neutralizing effect. To monitor the progression of postattachment interference, we synchronized the entry process at initiation and measured the escape of cell-bound virus from antibody. We found that different antibodies neutralized the virus over different time frames during the entry phase. Virus was observed to progress through a sequence of shifting sensitivities to different antibodies during entry, suggested here to correlate with the exposure time of the target epitope on receptor-activated viral envelope proteins. Thus, by monitoring the progression of HIV-1 entry under synchronized conditions, we identify a new and significant determinant of antibody neutralization capacity, namely, the time frames for neutralization during the course of the viral entry phase.
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Affiliation(s)
- Hillel Haim
- Department of Virology, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel.
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Anzinger JJ, Mezo I, Ji X, Gabali AM, Thomas LL, Spear GT. HIV infection of mononuclear cells is calcium-dependent. Virus Res 2006; 122:183-8. [PMID: 16842879 DOI: 10.1016/j.virusres.2006.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Revised: 06/02/2006] [Accepted: 06/07/2006] [Indexed: 01/03/2023]
Abstract
Strategies that prevent initial HIV infection of cells are greatly needed. In this study, we determined the requirement of divalent cations for HIV infection of and attachment to peripheral blood mononuclear cells (PBMC), which contain several types of HIV-infectable cells-CD4(+) T cells, monocytes and dendritic cells. EDTA, added only during PBMC exposure to HIV, reduced infection by an average of 92%. The reduction of infection by EDTA was accompanied by a reduction in HIV binding to PBMC; R5, X4 and dual-tropic HIV binding to PBMC were inhibited by >85%. EGTA similarly reduced HIV binding to PBMC, while addition of Ca(2+) or Mn(2+), but not Mg(2+), fully restored binding. Virus attachment was inhibited in a dose-dependent manner by trypsin treatment of PBMC, indicating protein involvement in HIV binding. In contrast, mannan or soluble ICAM-1 did not inhibit HIV binding to PBMC. These data indicate that a Ca(2+)-dependent cell-surface protein(s) is responsible for the majority of HIV attachment to and infection of PBMC. Further studies of this are likely to reveal novel strategies to prevent infection of PBMC.
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Affiliation(s)
- Joshua J Anzinger
- Department of Immunology and Microbiology, Rush University Medical Center, 1735 W. Harrison St., Cohn Building, Chicago, IL 60612, USA
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Chaipan C, Soilleux EJ, Simpson P, Hofmann H, Gramberg T, Marzi A, Geier M, Stewart EA, Eisemann J, Steinkasserer A, Suzuki-Inoue K, Fuller GL, Pearce AC, Watson SP, Hoxie JA, Baribaud F, Pöhlmann S. DC-SIGN and CLEC-2 mediate human immunodeficiency virus type 1 capture by platelets. J Virol 2006; 80:8951-60. [PMID: 16940507 PMCID: PMC1563896 DOI: 10.1128/jvi.00136-06] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelets can engulf human immunodeficiency virus type 1 (HIV-1), and a significant amount of HIV-1 in the blood of infected individuals is associated with these cells. However, it is unclear how platelets capture HIV-1 and whether platelet-associated virus remains infectious. DC-SIGN and other lectins contribute to capture of HIV-1 by dendritic cells (DCs) and facilitate HIV-1 spread in DC/T-cell cocultures. Here, we show that platelets express both the C-type lectin-like receptor 2 (CLEC-2) and low levels of DC-SIGN. CLEC-2 bound to HIV-1, irrespective of the presence of the viral envelope protein, and facilitated HIV-1 capture by platelets. However, a substantial fraction of the HIV-1 binding activity of platelets was dependent on DC-SIGN. A combination of DC-SIGN and CLEC-2 inhibitors strongly reduced HIV-1 association with platelets, indicating that these lectins are required for efficient HIV-1 binding to platelets. Captured HIV-1 was maintained in an infectious state over several days, suggesting that HIV-1 can escape degradation by platelets and might use these cells to promote its spread. Our results identify CLEC-2 as a novel HIV-1 attachment factor and provide evidence that platelets capture and transfer infectious HIV-1 via DC-SIGN and CLEC-2, thereby possibly facilitating HIV-1 dissemination in infected patients.
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Affiliation(s)
- Chawaree Chaipan
- Nikolaus-Fiebiger-Center for Molecular Medicine, University Erlangen-Nürnberg, Glückstrasse 6, 91054 Erlangen, Germany
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Saphire ACS, Gallay PA, Bark SJ. Proteomic Analysis of Human Immunodeficiency Virus Using Liquid Chromatography/Tandem Mass Spectrometry Effectively Distinguishes Specific Incorporated Host Proteins. J Proteome Res 2006; 5:530-8. [PMID: 16512667 DOI: 10.1021/pr050276b] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A major challenge to studying virus-incorporated host proteins is the fact that they are not encoded by the viral genome. We used Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) on whole virions to obtain a snapshot of the HIV-1 proteome. We identified known viral and host-cellular proteins and also identified novel components of HIV-1 and confirm these by traditional biochemical methods. Our comparison of wild-type and mutant viruses demonstrates that LC-MS/MS has the specificity to distinguish the presence/absence of a single host protein in intact virions.
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Affiliation(s)
- Andrew C S Saphire
- The Center for Protein Sciences and Department of Immunology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, USA
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Chandrashekran A, Gordon MY, Casimir C. Targeted retroviral transduction of c-kit+ hematopoietic cells using novel ligand display technology. Blood 2004; 104:2697-703. [PMID: 15256424 DOI: 10.1182/blood-2003-10-3717] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractGene therapy for a wide variety of disorders would be greatly enhanced by the development of vectors that could be targeted for gene delivery to specific populations of cells. We describe here high-efficiency targeted transduction based on a novel targeting strategy that exploits the ability of retroviruses to incorporate host cell proteins into the surface of the viral particle as they bud through the plasma membrane. Ecotropic retroviral particles produced in cells engineered to express the membrane-bound form of stem cell factor (mbSCF) transduce both human cell lines and primary cells with high efficiency in a strictly c-kit (SCF receptor)-dependent fashion. The availability of efficient targeted vectors provides a platform for the development of a new generation of therapies using in vivo gene delivery. (Blood. 2004;104: 2697-2703)
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Affiliation(s)
- Anil Chandrashekran
- Department of Haematology, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Rd, London W12 0NN, United Kingdom
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Burrer R, Haessig-Einius S, Aubertin AM, Moog C. Polyclonal immunoglobulin G from patients neutralizes human immunodeficiency virus type 1 primary isolates by binding free virions, but without interfering with an initial CD4-independent attachment of the virus to primary blood mononuclear cells. J Virol 2003; 77:11385-97. [PMID: 14557624 PMCID: PMC229376 DOI: 10.1128/jvi.77.21.11385-11397.2003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the relationship between human immunodeficiency virus type 1 (HIV-1) primary isolate (PI) antibody-mediated neutralization and attachment to primary blood mononuclear cells (PBMC). Incubation of PIs with immunoglobulin G (IgG) purified from infected patients did not inhibit attachment of the viruses with PBMC, but partial to complete neutralization was achieved. Neutralization of PIs already fixed on the cells was achieved by some IgG samples only and was of limited intensity compared to the former neutralization protocol. On the contrary, the binding of IgG to free virions was shown to be sufficient to reach potent neutralization, as the infectivity of IgG-PI complexes purified from the bulk of antibodies before addition to PBMC was strongly diminished compared to mock-treated controls. Monoclonal antibodies to the CDR2 domain of CD4 completely inhibited the infection of PBMC without interfering with the attachment of PIs to the cells, suggesting that, under these experimental conditions, the initial attachment of viruses to PBMC involves alternative cellular receptors. This initial interaction may also involve other components of the viral envelope than gp120, as partial depletion of the surface glycoproteins of primary viral particles that resulted in an almost complete loss of infectivity did not impair attachment to PBMC. A limited inhibition of attachment was observed when interfering with putative interactions with cellular heparan sulfate, whereas no effect was observed for cellular CD147 or nucleolin or for virion-incorporated cyclophilin A. Altogether, our results favor a mechanism of neutralization of HIV-1 PIs by polyclonal IgG where antibodies predominantly bind free virions and neutralize without interfering with the attachment to PBMC, which, in this model, is mainly CD4 independent.
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Affiliation(s)
- Renaud Burrer
- Inserm U544, Institut de Virologie, Université Louis Pasteur, 67000 Strasbourg, France
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Tardif MR, Tremblay MJ. Presence of host ICAM-1 in human immunodeficiency virus type 1 virions increases productive infection of CD4+ T lymphocytes by favoring cytosolic delivery of viral material. J Virol 2003; 77:12299-309. [PMID: 14581566 PMCID: PMC254246 DOI: 10.1128/jvi.77.22.12299-12309.2003] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although there is now convincing evidence that the infectivity of human immunodeficiency virus type 1 (HIV-1) is increased by incorporation of host intercellular adhesion molecule 1 (ICAM-1) in budding virions, the exact mechanism(s) through which ICAM-1 can so significantly affect HIV-1 biology remains obscure. To address this question, we focused our attention on the most proximal events in the virus life cycle. We made comparative analyses to estimate attachment and internalization of isogenic HIV-1 particles either lacking or bearing host-derived ICAM-1. Using attachment-and-entry assays and confocal fluorescence microscopy, we found that virus binding and uptake were both markedly enhanced by insertion of ICAM-1 within the virus envelope when PM1 lymphoid cells and primary human cells (i.e., peripheral blood lymphocytes and purified CD4(+) T cells) were used as targets. Moreover, ICAM-1-bearing virions entered cells with faster uptake kinetics than viruses devoid of ICAM-1. Experiments conducted with fully competent viruses further confirmed the positive effect of virion-anchored host ICAM-1 on HIV-1 replication. Interestingly, subcellular-fractionation assays revealed that ICAM-1 incorporation modifies the HIV-1 entry route by increasing the level of viral material released in the cytosol, a process of internalization known to be mediated mainly by pH-independent membrane fusion and to result in productive infection. A virion-based fusion assay confirmed that the acquisition of ICAM-1 increases the efficiency of productive HIV-1 entry in primary CD4(+) T lymphocytes. These observations provide new insights into how interactions other than those with gp120 and CD4-coreceptor complex can modulate the process of productive HIV-1 infection in CD4(+) T lymphocytes, a cell target highly relevant to HIV-1 pathogenesis.
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Affiliation(s)
- Mélanie R Tardif
- Research Center in Infectious Diseases, CHUL Research Center, Quebec, Canada
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Abstract
Human immunodeficiency virus type-1 particles contain host proteins, both on their surface and interior. This review summarises the cellular proteins found in these virions and covers some of their potential roles in the viral life cycle and pathogenesis. For most proteins studied, their role and function are either unknown or in the hypothesis stage. This reflects the relatively recent emphasis given to these proteins by the HIV-1 field as well as the incomplete understanding of their function in the cell. The study of cellular proteins in HIV-1 promises to help us better understand the interaction of this virus with the cell, the immune system, and the whole human host as well as to shed light on the nature of AIDS and suggest more targets for therapeutic intervention. Finally, many of the cell systems themselves are still poorly understood. The extensive study of HIV-1 has already brought increased attention to the fields of immunology and vaccine science and, in the same way, might assist our understanding of the cellular pathways themselves.
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Affiliation(s)
- David E Ott
- AIDS Vaccine Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA.
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