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Moranguinho I, Taveira N, Bártolo I. Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds. Int J Mol Sci 2023; 24:ijms24065905. [PMID: 36982978 PMCID: PMC10053740 DOI: 10.3390/ijms24065905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/08/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Currently, it is estimated that 1-2 million people worldwide are infected with HIV-2, accounting for 3-5% of the global burden of HIV. The course of HIV-2 infection is longer compared to HIV-1 infection, but without effective antiretroviral therapy (ART), a substantial proportion of infected patients will progress to AIDS and die. Antiretroviral drugs in clinical use were designed for HIV-1 and, unfortunately, some do not work as well, or do not work at all, for HIV-2. This is the case for non-nucleoside reverse transcriptase inhibitors (NNRTIs), the fusion inhibitor enfuvirtide (T-20), most protease inhibitors (PIs), the attachment inhibitor fostemsavir and most broadly neutralizing antibodies. Integrase inhibitors work well against HIV-2 and are included in first-line therapeutic regimens for HIV-2-infected patients. However, rapid emergence of drug resistance and cross-resistance within each drug class dramatically reduces second-line treatment options. New drugs are needed to treat infection with drug-resistant isolates. Here, we review the therapeutic armamentarium available to treat HIV-2-infected patients, as well as promising drugs in development. We also review HIV-2 drug resistance mutations and resistance pathways that develop in HIV-2-infected patients under treatment.
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Affiliation(s)
- Inês Moranguinho
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
| | - Nuno Taveira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Superior de Ciências da Saúde Egas Moniz, 2829-511 Caparica, Portugal
| | - Inês Bártolo
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
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2
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Tzou PL, Descamps D, Rhee SY, Raugi DN, Charpentier C, Taveira N, Smith RA, Soriano V, de Mendoza C, Holmes SP, Gottlieb GS, Shafer RW. Expanded Spectrum of Antiretroviral-Selected Mutations in Human Immunodeficiency Virus Type 2. J Infect Dis 2021; 221:1962-1972. [PMID: 31965175 DOI: 10.1093/infdis/jiaa026] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/17/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND HIV-1 and HIV-2 differ in their antiretroviral (ARV) susceptibilities and drug resistance mutations (DRMs). METHODS We analyzed published HIV-2 pol sequences to identify HIV-2 treatment-selected mutations (TSMs). Mutation prevalences were determined by HIV-2 group and ARV status. Nonpolymorphic mutations were those in <1% of ARV-naive persons. TSMs were those associated with ARV therapy after multiple comparisons adjustment. RESULTS We analyzed protease (PR) sequences from 483 PR inhibitor (PI)-naive and 232 PI-treated persons; RT sequences from 333 nucleoside RT inhibitor (NRTI)-naive and 252 NRTI-treated persons; and integrase (IN) sequences from 236 IN inhibitor (INSTI)-naive and 60 INSTI-treated persons. In PR, 12 nonpolymorphic TSMs occurred in ≥11 persons: V33I, K45R, V47A, I50V, I54M, T56V, V62A, A73G, I82F, I84V, F85L, L90M. In RT, 9 nonpolymorphic TSMs occurred in ≥10 persons: K40R, A62V, K70R, Y115F, Q151M, M184VI, S215Y. In IN, 11 nonpolymorphic TSMs occurred in ≥4 persons: Q91R, E92AQ, T97A, G140S, Y143G, Q148R, A153G, N155H, H156R, R231 5-amino acid insertions. Nine of 32 nonpolymorphic TSMs were previously unreported. CONCLUSIONS This meta-analysis confirmed the ARV association of previously reported HIV-2 DRMs and identified novel TSMs. Genotypic and phenotypic studies of HIV-2 TSMs will improve approaches to predicting HIV-2 ARV susceptibility and treating HIV-2-infected persons.
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Affiliation(s)
- Philip L Tzou
- Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, California, USA
| | - Diane Descamps
- Laboratoire de Virologie, Hôpital Bichat-Claude Bernard, APHP.Nord Universite de Paris, France.,INSERM UMR 1137, Paris, France
| | - Soo-Yon Rhee
- Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, California, USA
| | - Dana N Raugi
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Charlotte Charpentier
- Laboratoire de Virologie, Hôpital Bichat-Claude Bernard, APHP.Nord Universite de Paris, France.,INSERM UMR 1137, Paris, France
| | - Nuno Taveira
- Research Institute for Medicines, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.,Instituto Universitário Egas Moniz, Monte da Caparica, Portugal
| | - Robert A Smith
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Vicente Soriano
- Health Sciences School and Medical Center, Universidad Internacional de La Rioja, Madrid, Spain
| | - Carmen de Mendoza
- Puerta de Hierro University Hospital and Research Institute, Madrid, Spain
| | - Susan P Holmes
- Department of Statistics, Stanford University, Stanford, California, USA
| | - Geoffrey S Gottlieb
- Department of Medicine, University of Washington, Seattle, Washington, USA.,Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Robert W Shafer
- Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, California, USA
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3
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Wöhrl BM. Structural and Functional Aspects of Foamy Virus Protease-Reverse Transcriptase. Viruses 2019; 11:v11070598. [PMID: 31269675 PMCID: PMC6669543 DOI: 10.3390/v11070598] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 12/15/2022] Open
Abstract
Reverse transcription describes the process of the transformation of single-stranded RNA into double-stranded DNA via an RNA/DNA duplex intermediate, and is catalyzed by the viral enzyme reverse transcriptase (RT). This event is a pivotal step in the life cycle of all retroviruses. In contrast to orthoretroviruses, the domain structure of the mature RT of foamy viruses is different, i.e., it harbors the protease (PR) domain at its N-terminus, thus being a PR-RT. This structural feature has consequences on PR activation, since the enzyme is monomeric in solution and retroviral PRs are only active as dimers. This review focuses on the structural and functional aspects of simian and prototype foamy virus reverse transcription and reverse transcriptase, as well as special features of reverse transcription that deviate from orthoretroviral processes, e.g., PR activation.
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Affiliation(s)
- Birgitta M Wöhrl
- Lehrstuhl Biopolymere, Universität Bayreuth, D-95440 Bayreuth, Germany.
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4
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90-90-90 for HIV-2? Ending the HIV-2 epidemic by enhancing care and clinical management of patients infected with HIV-2. Lancet HIV 2019; 5:e390-e399. [PMID: 30052509 DOI: 10.1016/s2352-3018(18)30094-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 12/23/2022]
Abstract
Distinct from HIV-1 and often neglected in the global campaign to end the AIDS epidemic, HIV-2 presents unique and underappreciated challenges in diagnosis, clinical care, antiretroviral therapy (ART), and HIV programmatic management. Here, we review the epidemiology and natural history of HIV-2, diagnostics and algorithms for accurately diagnosing and differentiating HIV-2 from HIV-1, the unique features of HIV-2 ART and drug resistance, and the clinical care and management of patients infected with HIV-2 in both developed and resource-limited settings. Ultimately, further research is needed to address the gaps in our knowledge of HIV-2 infection, increased resources are needed to specifically target HIV-2 as part of the UNAIDS/WHO 90-90-90 campaign to end AIDS, and increased determination is needed to better advocate for inclusion of people living with HIV-2 in global HIV/AIDS initiatives.
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5
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The High Genetic Barrier of EFdA/MK-8591 Stems from Strong Interactions with the Active Site of Drug-Resistant HIV-1 Reverse Transcriptase. Cell Chem Biol 2018; 25:1268-1278.e3. [PMID: 30174310 DOI: 10.1016/j.chembiol.2018.07.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/14/2018] [Accepted: 07/27/2018] [Indexed: 12/12/2022]
Abstract
4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA/MK-8591), a nucleoside reverse transcriptase inhibitor (NRTI) under clinical trials, is a potent and promising long-acting anti-HIV type 1 (HIV-1) agent. EFdA and its derivatives possess a modified 4'-moiety and potently inhibit the replication of a wide spectrum of HIV-1 strains resistant to existing NRTIs. Here, we report that EFdA and NRTIs with a 4'-ethynyl- or 4'-cyano-moiety exerted activity against HIV-1 with an M184V mutation and multiple NRTI-resistant HIV-1s, whereas NRTIs with other moieties (e.g., 4'-methyl) did not show this activity. Structural analysis indicated that EFdA and 4'-ethynyl-NRTIs (but not other 4'-modified NRTIs), formed strong van der Waals interactions with critical amino acid residues of reverse transcriptase. Such interactions were maintained even in the presence of a broad resistance-endowing M184V substitution, thus potently inhibiting drug-resistant HIV-1 strains. These findings also explain the mechanism for the potency of EFdA and provide insights for further design of anti-HIV-1 therapeutics.
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6
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Seley-Radtke KL, Yates MK. The evolution of nucleoside analogue antivirals: A review for chemists and non-chemists. Part 1: Early structural modifications to the nucleoside scaffold. Antiviral Res 2018; 154:66-86. [PMID: 29649496 PMCID: PMC6396324 DOI: 10.1016/j.antiviral.2018.04.004] [Citation(s) in RCA: 302] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/22/2018] [Accepted: 04/04/2018] [Indexed: 02/07/2023]
Abstract
This is the first of two invited articles reviewing the development of nucleoside-analogue antiviral drugs, written for a target audience of virologists and other non-chemists, as well as chemists who may not be familiar with the field. Rather than providing a simple chronological account, we have examined and attempted to explain the thought processes, advances in synthetic chemistry and lessons learned from antiviral testing that led to a few molecules being moved forward to eventual approval for human therapies, while others were discarded. The present paper focuses on early, relatively simplistic changes made to the nucleoside scaffold, beginning with modifications of the nucleoside sugars of Ara-C and other arabinose-derived nucleoside analogues in the 1960's. A future paper will review more recent developments, focusing especially on more complex modifications, particularly those involving multiple changes to the nucleoside scaffold. We hope that these articles will help virologists and others outside the field of medicinal chemistry to understand why certain drugs were successfully developed, while the majority of candidate compounds encountered barriers due to low-yielding synthetic routes, toxicity or other problems that led to their abandonment. This is the first of two invited articles reviewing the development of nucleoside-analogue antiviral drugs. It is written for a target audience of virologists and other non-chemists, and for chemists unfamiliar with the field. Numerous modifications have been made to the nucleoside scaffold in order to impart therapeutic benefits. Nucleoside modifications led to the development of potent antivirals such as acyclovir, entecavir, and tenofovir. We examine thought processes, progress in synthetic chemistry and results of antiviral testing that led to approved drugs.
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Affiliation(s)
- Katherine L Seley-Radtke
- 1000 Hilltop Circle, Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, USA.
| | - Mary K Yates
- 1000 Hilltop Circle, Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, USA
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7
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HIV-1 with HBV-associated Q151M substitution in RT becomes highly susceptible to entecavir: structural insights into HBV-RT inhibition by entecavir. Sci Rep 2018; 8:1624. [PMID: 29374261 PMCID: PMC5785976 DOI: 10.1038/s41598-018-19602-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/02/2018] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B virus (HBV) reverse transcriptase (RT) is essential for viral replication and is an important drug target. Nonetheless, the notorious insolubility of HBV RT has hindered experimental structural studies and structure-based drug design. Here, we demonstrate that a Q151M substitution alone at the nucleotide-binding site (N-site) of human immunodeficiency virus type-1 (HIV-1) RT renders HIV-1 highly sensitive to entecavir (ETV), a potent nucleoside analogue RT inhibitor (NRTI) against HBV. The results suggest that Met151 forms a transient hydrophobic interaction with the cyclopentyl methylene of ETV, a characteristic hydrophobic moiety of ETV. We thus solved the crystal structures of HIV-1 RTQ151M:DNA complex with bound dGTP or ETV-triphosphate (ETV-TP). The structures revealed that ETV-TP is accommodated at the N-site slightly apart from the ribose ring of the 3′-end nucleotide, compared to the position of bound dGTP and previously reported NRTI/dNTP. In addition, the protruding methylene group of bound ETV-TP directly pushes the side-chain of Met184 backward. Met184 is a key residue that confers ETV resistance upon substitution with smaller Ile/Val. These results provide novel insights into NRTI binding to the N-site and further provide important clues for the development of novel anti-HBV/HIV-1 RT inhibitors to overcome critical drug resistance.
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8
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Álvarez M, Nevot M, Mendieta J, Martínez MA, Menéndez-Arias L. Amino acid residues in HIV-2 reverse transcriptase that restrict the development of nucleoside analogue resistance through the excision pathway. J Biol Chem 2017; 293:2247-2259. [PMID: 29275329 DOI: 10.1074/jbc.ra117.000177] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/21/2017] [Indexed: 01/13/2023] Open
Abstract
Nucleoside reverse transcriptase (RT) inhibitors (NRTIs) are the backbone of current antiretroviral treatments. However, the emergence of viral resistance against NRTIs is a major threat to their therapeutic effectiveness. In HIV-1, NRTI resistance-associated mutations either reduce RT-mediated incorporation of NRTI triphosphates (discrimination mechanism) or confer an ATP-mediated nucleotide excision activity that removes the inhibitor from the 3' terminus of DNA primers, enabling further primer elongation (excision mechanism). In HIV-2, resistance to zidovudine (3'-azido-3'-deoxythymidine (AZT)) and other NRTIs is conferred by mutations affecting nucleotide discrimination. Mutations of the excision pathway such as M41L, D67N, K70R, or S215Y (known as thymidine-analogue resistance mutations (TAMs)) are rare in the virus from HIV-2-infected individuals. Here, we demonstrate that mutant M41L/D67N/K70R/S215Y HIV-2 RT lacks ATP-dependent excision activity, and recombinant virus containing this RT remains susceptible to AZT inhibition. Mutant HIV-2 RTs were tested for their ability to unblock and extend DNA primers terminated with AZT and other NRTIs, when complexed with RNA or DNA templates. Our results show that Met73 and, to a lesser extent, Ile75 suppress excision activity when TAMs are present in the HIV-2 RT. Interestingly, recombinant HIV-2 carrying a mutant D67N/K70R/M73K RT showed 10-fold decreased AZT susceptibility and increased rescue efficiency on AZT- or tenofovir-terminated primers, as compared with the double-mutant D67N/K70R. Molecular dynamics simulations reveal that Met73influences β3-β4 hairpin loop conformation, whereas its substitution affects hydrogen bond interactions at position 70, required for NRTI excision. Our work highlights critical HIV-2 RT residues impeding the development of excision-mediated NRTI resistance.
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Affiliation(s)
- Mar Álvarez
- From the Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid
| | - María Nevot
- the Laboratori de Retrovirologia, Fundació irsiCaixa, Hospital Universitari Germans Trias i Pujol, Badalona, 08916 Barcelona, and
| | - Jesús Mendieta
- From the Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid.,the Departamento de Biotecnología, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Miguel A Martínez
- the Laboratori de Retrovirologia, Fundació irsiCaixa, Hospital Universitari Germans Trias i Pujol, Badalona, 08916 Barcelona, and
| | - Luis Menéndez-Arias
- From the Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid,
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9
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High-Frequency Illegitimate Strand Transfers of Nascent DNA Fragments During Reverse Transcription Result in Defective Retrovirus Genomes. J Acquir Immune Defic Syndr 2017; 72:353-62. [PMID: 26885810 DOI: 10.1097/qai.0000000000000952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Two strand transfers of nascent DNA fragments during reverse transcription are required for retrovirus replication. However, whether strand transfers occur at illegitimate sites and how this may affect retrovirus replication are not well understood. METHODS The reverse transcription was carried out with reverse transcriptases (RTs) from HIV-1, HIV-2, and murine leukemia virus. The nascent complementary DNA fragments were directly cloned without polymerase chain reaction amplification. The sequences were compared with the template sequence to determine if new sequences contained mismatched sequences caused by illegitimate strand transfers. RESULTS Among 1067 nascent reverse transcript sequences, most of them (72%) matched to the template sequences, although they randomly stopped across the RNA templates. The other 28% of them contained mismatched 3'-end sequences because of illegitimate strand transfers. Most of the illegitimate strand transfers (81%) were disassociated from RNA templates and realigned onto opposite complementary DNA strands. Up to 3 strand transfers were detected in a single sequence, whereas most of them (93%) contained 1 strand transfer. Because most of the illegitimate strand-transfer fragments were generated from templates at 2 opposite orientations, they resulted in defective viral genomes and could not be detected by previous methods. Further analysis showed that mutations at pause/disassociation sites resulted in significantly higher strand-transfer rates. Moreover, illegitimate strand-transfer rates were significantly higher for HIV-2 RT (38.2%) and murine leukemia virus RT (44.6%) than for HIV-1 RT (5.1%). CONCLUSIONS Illegitimate strand transfers frequently occur during reverse transcription and can result in a large portion of defective retrovirus genomes.
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10
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MK-8591 (4'-Ethynyl-2-Fluoro-2'-Deoxyadenosine) Exhibits Potent Activity against HIV-2 Isolates and Drug-Resistant HIV-2 Mutants in Culture. Antimicrob Agents Chemother 2017; 61:AAC.00744-17. [PMID: 28559249 DOI: 10.1128/aac.00744-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/19/2017] [Indexed: 11/20/2022] Open
Abstract
There is a pressing need to identify more effective antiretroviral drugs for HIV-2 treatment. Here, we show that the investigational compound MK-8591 (4'-ethynyl-2-fluoro-2'-deoxyadenosine [EFdA]) is highly active against group A and B isolates of HIV-2; 50% effective concentrations [EC50] for HIV-2 were, on average, 4.8-fold lower than those observed for HIV-1. MK-8591 also retains potent activity against multinucleoside-resistant HIV-2 mutants (EC50 ≤ 11 nM). These data suggest that MK-8591 may have antiviral activity in HIV-2-infected individuals.
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Achuthan V, Singh K, DeStefano JJ. Physiological Mg 2+ Conditions Significantly Alter the Inhibition of HIV-1 and HIV-2 Reverse Transcriptases by Nucleoside and Non-Nucleoside Inhibitors in Vitro. Biochemistry 2016; 56:33-46. [PMID: 27936595 DOI: 10.1021/acs.biochem.6b00943] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reverse transcriptases (RTs) are typically assayed in vitro with 5-10 mM Mg2+, whereas the free Mg2+ concentration in cells is much lower. Artificially high Mg2+ concentrations used in vitro can misrepresent different properties of human immunodeficiency virus (HIV) RT, including fidelity, catalysis, pausing, and RNase H activity. Here, we analyzed nucleoside (NRTIs) and non-nucleoside RT inhibitors (NNRTIs) in primer extension assays at different concentrations of free Mg2+. At low concentrations of Mg2+, NRTIs and dideoxynucleotides (AZTTP, ddCTP, ddGTP, and 3TCTP) inhibited HIV-1 and HIV-2 RT synthesis less efficiently than they did with large amounts of Mg2+, whereas inhibition by the "translocation-defective RT inhibitor" EFdA (4'-ethynyl-2-fluoro-2'-deoxyadenosine) was unaffected by Mg2+ concentrations. Steady-state kinetic analyses revealed that the reduced level of inhibition at low Mg2+ concentrations resulted from a 3-9-fold (depending on the particular nucleotide and inhibitor) less efficient incorporation (based on kcat/Km) of these NRTIs under this condition compared to incorporation of natural dNTPs. In contrast, EFdATP was incorporated with an efficiency similar to that of its analogue dATP at low Mg2+ concentrations. Unlike NRTIs, NNRTIs (nevirapine, efavirenz, and rilviripine), were approximately 4-fold (based on IC50 values) more effective at low than at high Mg2+ concentrations. Drug-resistant HIV-1 RT mutants also displayed the Mg2+-dependent difference in susceptibility to NRTIs and NNRTIs. In summary, analyzing the efficiency of inhibitors under more physiologically relevant low-Mg2+ conditions yielded results dramatically different from those from measurements using commonly employed high-Mg2+ in vitro conditions. These results also emphasize differences in Mg2+ sensitivity between the translocation inhibitor EFdATP and other NRTIs.
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Affiliation(s)
- Vasudevan Achuthan
- Cell Biology and Molecular Genetics, University of Maryland , College Park, Maryland 20742, United States.,Maryland Pathogen Research Institute , College Park, Maryland 20742, United States
| | - Kamlendra Singh
- Christopher S. Bond Life Sciences Center, University of Missouri , Columbia, Missouri 65211, United States.,Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine , Columbia, Missouri 65211, United States
| | - Jeffrey J DeStefano
- Cell Biology and Molecular Genetics, University of Maryland , College Park, Maryland 20742, United States.,Maryland Pathogen Research Institute , College Park, Maryland 20742, United States
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12
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Visseaux B, Damond F, Matheron S, Descamps D, Charpentier C. Hiv-2 molecular epidemiology. INFECTION GENETICS AND EVOLUTION 2016; 46:233-240. [PMID: 27530215 DOI: 10.1016/j.meegid.2016.08.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/13/2022]
Abstract
The Simian Immunodeficiency Virus of sooty mangabeys (SIVsmm) has been revealed to be at the origin of Human Immunodeficiency Virus type 2 (HIV-2) in humans, firstly detected from two Portuguese patients in 1986. HIV-2 is mainly restricted to West Africa where it infects up to 1 to 2 million people. HIV-2 is also present in Europe, mainly Portugal and France, India and United States of America. Two major HIV-2 groups, groups A and B, were generated by two independent transmission events involving infected sooty mangabeys from the Taï forest in Ivory Coast. Seven other HIV-2 groups have been described, but each has only been identified in one patient. To date, no subtypes have been formally described but some preliminary data suggest that HIV-2 group A may be divided in two distinct subtypes with distinct geographical origins. To date only two recombinant forms have been described: one circulating recombinant form (CRF01_AB) and one unique recombinant form. In this review, we focused mainly on molecular data available and their insights about HIV-2 origins, diversity, drug resistance and global epidemiology.
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Affiliation(s)
- Benoit Visseaux
- INSERM, IAME, UMR 1137, F-75018 Paris, France; Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, F-75018 Paris, France; AP-HP, Hôpital Bichat, Laboratoire de Virologie, F-75018 Paris, France.
| | - Florence Damond
- INSERM, IAME, UMR 1137, F-75018 Paris, France; Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, F-75018 Paris, France; AP-HP, Hôpital Bichat, Laboratoire de Virologie, F-75018 Paris, France
| | - Sophie Matheron
- INSERM, IAME, UMR 1137, F-75018 Paris, France; Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, F-75018 Paris, France; AP-HP, Hôpital Bichat, Service de Maladies Infectieuses et Tropicales, F-75018 Paris, France
| | - Diane Descamps
- INSERM, IAME, UMR 1137, F-75018 Paris, France; Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, F-75018 Paris, France; AP-HP, Hôpital Bichat, Laboratoire de Virologie, F-75018 Paris, France
| | - Charlotte Charpentier
- INSERM, IAME, UMR 1137, F-75018 Paris, France; Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, F-75018 Paris, France; AP-HP, Hôpital Bichat, Laboratoire de Virologie, F-75018 Paris, France
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Abstract
Diversity-generating retroelements (DGRs) are DNA diversification machines found in diverse bacterial and bacteriophage genomes that accelerate the evolution of ligand-receptor interactions. Diversification results from a unidirectional transfer of sequence information from an invariant template repeat (TR) to a variable repeat (VR) located in a protein-encoding gene. Information transfer is coupled to site-specific mutagenesis in a process called mutagenic homing, which occurs through an RNA intermediate and is catalyzed by a unique, DGR-encoded reverse transcriptase that converts adenine residues in the TR into random nucleotides in the VR. In the prototype DGR found in the Bordetella bacteriophage BPP-1, the variable protein Mtd is responsible for phage receptor recognition. VR diversification enables progeny phage to switch tropism, accelerating their adaptation to changes in sequence or availability of host cell-surface molecules for infection. Since their discovery, hundreds of DGRs have been identified, and their functions are just beginning to be understood. VR-encoded residues of many DGR-diversified proteins are displayed in the context of a C-type lectin fold, although other scaffolds, including the immunoglobulin fold, may also be used. DGR homing is postulated to occur through a specialized target DNA-primed reverse transcription mechanism that allows repeated rounds of diversification and selection, and the ability to engineer DGRs to target heterologous genes suggests applications for bioengineering. This chapter provides a comprehensive review of our current understanding of this newly discovered family of beneficial retroelements.
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14
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Schneider A, Corona A, Spöring I, Jordan M, Buchholz B, Maccioni E, Di Santo R, Bodem J, Tramontano E, Wöhrl BM. Biochemical characterization of a multi-drug resistant HIV-1 subtype AG reverse transcriptase: antagonism of AZT discrimination and excision pathways and sensitivity to RNase H inhibitors. Nucleic Acids Res 2016; 44:2310-22. [PMID: 26850643 PMCID: PMC4797301 DOI: 10.1093/nar/gkw060] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 01/24/2016] [Indexed: 11/27/2022] Open
Abstract
We analyzed a multi-drug resistant (MR) HIV-1 reverse transcriptase (RT), subcloned from a patient-derived subtype CRF02_AG, harboring 45 amino acid exchanges, amongst them four thymidine analog mutations (TAMs) relevant for high-level AZT (azidothymidine) resistance by AZTMP excision (M41L, D67N, T215Y, K219E) as well as four substitutions of the AZTTP discrimination pathway (A62V, V75I, F116Y and Q151M). In addition, K65R, known to antagonize AZTMP excision in HIV-1 subtype B was present. Although MR-RT harbored the most significant amino acid exchanges T215Y and Q151M of each pathway, it exclusively used AZTTP discrimination, indicating that the two mechanisms are mutually exclusive and that the Q151M pathway is obviously preferred since it confers resistance to most nucleoside inhibitors. A derivative was created, additionally harboring the TAM K70R and the reversions M151Q as well as R65K since K65R antagonizes excision. MR-R65K-K70R-M151Q was competent of AZTMP excision, whereas other combinations thereof with only one or two exchanges still promoted discrimination. To tackle the multi-drug resistance problem, we tested if the MR-RTs could still be inhibited by RNase H inhibitors. All MR-RTs exhibited similar sensitivity toward RNase H inhibitors belonging to different inhibitor classes, indicating the importance of developing RNase H inhibitors further as anti-HIV drugs.
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Affiliation(s)
- Anna Schneider
- Universität Bayreuth, Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, SS 554, 09042, Monserrato, Cagliari, Italy
| | - Imke Spöring
- Julius-Maximilians-Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Strasse 7, 97078 Würzburg, Germany
| | - Mareike Jordan
- Universität Bayreuth, Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Bernd Buchholz
- Universität Heidelberg, Medizinische Fakultät Mannheim, Klinik für Kinder- und Jugendmedizin, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Elias Maccioni
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, SS 554, 09042, Monserrato, Cagliari, Italy
| | - Roberto Di Santo
- Dipartimento di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci Bolognetti, "Sapienza" Università di Roma, Rome, I-00185, Italy
| | - Jochen Bodem
- Julius-Maximilians-Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Strasse 7, 97078 Würzburg, Germany
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, SS 554, 09042, Monserrato, Cagliari, Italy
| | - Birgitta M Wöhrl
- Universität Bayreuth, Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universitätsstrasse 30, 95447 Bayreuth, Germany
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Hollenbaugh JA, Schader SM, Schinazi RF, Kim B. Differential regulatory activities of viral protein X for anti-viral efficacy of nucleos(t)ide reverse transcriptase inhibitors in monocyte-derived macrophages and activated CD4(+) T cells. Virology 2015; 485:313-21. [PMID: 26319213 PMCID: PMC4619155 DOI: 10.1016/j.virol.2015.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/27/2015] [Accepted: 08/08/2015] [Indexed: 01/05/2023]
Abstract
Vpx encoded by HIV-2 and SIVsm enhances retroviral reverse transcription in macrophages in vitro by mediating the degradation of the host SAMHD1 protein that hydrolyzes dNTPs and by elevating cellular dNTP levels. Here we employed RT-SHIV constructs (SIV encoding HIV-1 RT) to investigate the contribution of Vpx to the potency of NRTIs, which compete against dNTPs, in monocyte-derived macrophages (MDMs) and activated CD4(+) T cells. Relative to HIV-1, both SIV and RT-SHIV exhibited reduced sensitivities to AZT, 3TC and TDF in MDMs but not in activated CD4(+) T cells. However, when SIV and RT-SHIV constructs not coding for Vpx were utilized, we observed greater sensitivities to all NRTIs tested using activated CD4(+) T cells relative to the Vpx-coding counterparts. This latter phenomenon was observed for AZT only when using MDMs. Our data suggest that Vpx in RT-SHIVs may underestimate the antiviral efficacy of NRTIs in a cell type dependent manner.
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Affiliation(s)
- Joseph A Hollenbaugh
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Susan M Schader
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Raymond F Schinazi
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; Veterans Affairs Medical Center, Atlanta, GA, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; College of Pharmacy, Kyung Hee University, Seoul, South Korea.
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The Nucleoside Analog BMS-986001 Shows Greater In Vitro Activity against HIV-2 than against HIV-1. Antimicrob Agents Chemother 2015; 59:7437-46. [PMID: 26392486 DOI: 10.1128/aac.01326-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/11/2015] [Indexed: 02/07/2023] Open
Abstract
Treatment options for individuals infected with human immunodeficiency virus type 2 (HIV-2) are restricted by the intrinsic resistance of the virus to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and the reduced susceptibility of HIV-2 to several protease inhibitors (PIs) used in antiretroviral therapy (ART). In an effort to identify new antiretrovirals for HIV-2 treatment, we evaluated the in vitro activity of the investigational nucleoside analog BMS-986001 (2',3'-didehydro-3'-deoxy-4'-ethynylthymidine; also known as censavudine, festinavir, OBP-601, 4'-ethynyl stavudine, or 4'-ethynyl-d4T). In single-cycle assays, BMS-986001 inhibited HIV-2 isolates from treatment-naive individuals, with 50% effective concentrations (EC50s) ranging from 30 to 81 nM. In contrast, EC50s for group M and O isolates of HIV-1 ranged from 450 to 890 nM. Across all isolates tested, the average EC50 for HIV-2 was 9.5-fold lower than that for HIV-1 (64 ± 18 nM versus 610 ± 200 nM, respectively; mean ± standard deviation). BMS-986001 also exhibited full activity against HIV-2 variants whose genomes encoded the single amino acid changes K65R and Q151M in reverse transcriptase, whereas the M184V mutant was 15-fold more resistant to the drug than the parental HIV-2ROD9 strain. Taken together, our findings show that BMS-986001 is an effective inhibitor of HIV-2 replication. To our knowledge, BMS-986001 is the first nucleoside analog that, when tested against a diverse collection of HIV-1 and HIV-2 isolates, exhibits more potent activity against HIV-2 than against HIV-1 in culture.
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Analysis of the Zidovudine Resistance Mutations T215Y, M41L, and L210W in HIV-1 Reverse Transcriptase. Antimicrob Agents Chemother 2015; 59:7184-96. [PMID: 26324274 DOI: 10.1128/aac.05069-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 08/23/2015] [Indexed: 01/01/2023] Open
Abstract
Although anti-human immunodeficiency virus type 1 (HIV-1) therapies have become more sophisticated and more effective, drug resistance continues to be a major problem. Zidovudine (azidothymidine; AZT) was the first nucleoside reverse transcriptase (RT) inhibitor (NRTI) approved for the treatment of HIV-1 infections and is still being used, particularly in the developing world. This drug targets the conversion of single-stranded RNA to double-stranded DNA by HIV-1 RT. However, resistance to the drug quickly appeared both in viruses replicating in cells in culture and in patients undergoing AZT monotherapy. The primary resistance pathway selects for mutations of T215 that change the threonine to either a tyrosine or a phenylalanine (T215Y/F); this resistance pathway involves an ATP-dependent excision mechanism. The pseudo-sugar ring of AZT lacks a 3' OH; RT incorporates AZT monophosphate (AZTMP), which blocks the end of the viral DNA primer. AZT-resistant forms of HIV-1 RT use ATP in an excision reaction to unblock the 3' end of the primer strand, allowing its extension by RT. The T215Y AZT resistance mutation is often accompanied by two other mutations, M41L and L210W. In this study, the roles of these mutations, in combination with T215Y, were examined to determine whether they affect polymerization and excision by HIV-1 RT. The M41L mutation appears to help restore the DNA polymerization activity of RT containing the T215Y mutation and also enhances AZTMP excision. The L210W mutation plays a similar role, but it enhances excision by RTs that carry the T215Y mutation when ATP is present at a low concentration.
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Ashok P, Chander S, Balzarini J, Pannecouque C, Murugesan S. Design, synthesis of new β-carboline derivatives and their selective anti-HIV-2 activity. Bioorg Med Chem Lett 2015; 25:1232-5. [DOI: 10.1016/j.bmcl.2015.01.058] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/10/2015] [Accepted: 01/23/2015] [Indexed: 11/28/2022]
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Deuzing IP, Charpentier C, Wright DW, Matheron S, Paton J, Frentz D, van de Vijver DA, Coveney PV, Descamps D, Boucher CAB, Beerens N. Mutation V111I in HIV-2 reverse transcriptase increases the fitness of the nucleoside analogue-resistant K65R and Q151M viruses. J Virol 2015; 89:833-43. [PMID: 25355888 PMCID: PMC4301157 DOI: 10.1128/jvi.02259-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/23/2014] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Infection with HIV-2 can ultimately lead to AIDS, although disease progression is much slower than with HIV-1. HIV-2 patients are mostly treated with a combination of nucleoside reverse transcriptase (RT) inhibitors (NRTIs) and protease inhibitors designed for HIV-1. Many studies have described the development of HIV-1 resistance to NRTIs and identified mutations in the polymerase domain of RT. Recent studies have shown that mutations in the connection and RNase H domains of HIV-1 RT may also contribute to resistance. However, only limited information exists regarding the resistance of HIV-2 to NRTIs. In this study, therefore, we analyzed the polymerase, connection, and RNase H domains of RT in HIV-2 patients failing NRTI-containing therapies. Besides the key resistance mutations K65R, Q151M, and M184V, we identified a novel mutation, V111I, in the polymerase domain. This mutation was significantly associated with mutations K65R and Q151M. Sequencing of the connection and RNase H domains of the HIV-2 patients did not reveal any of the mutations that were reported to contribute to NRTI resistance in HIV-1. We show that V111I does not strongly affect drug susceptibility but increases the replication capacity of the K65R and Q151M viruses. Biochemical assays demonstrate that V111I restores the polymerization defects of the K65R and Q151M viruses but negatively affects the fidelity of the HIV-2 RT enzyme. Molecular dynamics simulations were performed to analyze the structural changes mediated by V111I. This showed that V111I changed the flexibility of the 110-to-115 loop region, which may affect deoxynucleoside triphosphate (dNTP) binding and polymerase activity. IMPORTANCE Mutation V111I in the HIV-2 reverse transcriptase enzyme was identified in patients failing therapies containing nucleoside analogues. We show that the V111I change does not strongly affect the sensitivity of HIV-2 to nucleoside analogues but increases the fitness of viruses with drug resistance mutations K65R and Q151M.
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Affiliation(s)
- Ilona P Deuzing
- Department of Virology, Viroscience Laboratory, Erasmus MC, Rotterdam, the Netherlands
| | - Charlotte Charpentier
- INSERM, IAME, UMR 1137, University Paris Diderot, Sorbonne Paris Cité, Paris, France AP-HP, Hôpital Bichat, Laboratoire de Virologie, Paris, France
| | - David W Wright
- Centre for Computational Science, Department of Chemistry, University College London, London, United Kingdom Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Sophie Matheron
- INSERM, IAME, UMR 1137, University Paris Diderot, Sorbonne Paris Cité, Paris, France AP-HP, Hôpital Bichat, Service des Maladies Infecieuse et Tropicales, Paris, France
| | - Jack Paton
- Centre for Computational Science, Department of Chemistry, University College London, London, United Kingdom Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Dineke Frentz
- Department of Virology, Viroscience Laboratory, Erasmus MC, Rotterdam, the Netherlands
| | - David A van de Vijver
- Department of Virology, Viroscience Laboratory, Erasmus MC, Rotterdam, the Netherlands
| | - Peter V Coveney
- Centre for Computational Science, Department of Chemistry, University College London, London, United Kingdom
| | - Diane Descamps
- INSERM, IAME, UMR 1137, University Paris Diderot, Sorbonne Paris Cité, Paris, France AP-HP, Hôpital Bichat, Laboratoire de Virologie, Paris, France
| | - Charles A B Boucher
- Department of Virology, Viroscience Laboratory, Erasmus MC, Rotterdam, the Netherlands
| | - Nancy Beerens
- Department of Virology, Viroscience Laboratory, Erasmus MC, Rotterdam, the Netherlands
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Lange JMA, Ananworanich J. The discovery and development of antiretroviral agents. Antivir Ther 2014; 19 Suppl 3:5-14. [PMID: 25310317 DOI: 10.3851/imp2896] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2014] [Indexed: 10/24/2022]
Abstract
Since the discovery of HIV as the causative agent of AIDS in 1983/1984, remarkable progress has been made in finding antiretroviral drugs (ARVs) that are effective against it. A major breakthrough occurred in 1996 when it was found that triple drug therapy (HAART) could durably suppress viral replication to minimal levels. It was then widely felt, however, that HAART was too expensive and complex for low- and middle-income countries, and so, with the exception of a few of these countries, such as Brazil, a massive scale-up did not begin until the WHO launched its '3 by 5' initiative and sizeable funding mechanisms, such as the Global Fund to Fight AIDS, TB and Malaria and the US President's Emergency Plan for AIDS Relief (PEPFAR), came into existence. A pivotal enabler of the scale-up was a steady lowering of drug prices through entry of generic antiretrovirals, competition between generic manufacturers and the making of volume commitments. The WHO Prequalification of Medicines Programme and the Expedited Review Provision of the US Food and Drug Administration have been important for the assurance of quality standards. Antiretroviral drug development by research-based pharmaceutical companies continues, with several important innovative products, such as long-acting agents, in the pipeline.
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Affiliation(s)
- Joep M A Lange
- Department of Global Health, Academic Medical Center, University of Amsterdam, Amsterdam Institute for Global Health and Development, Amsterdam, the Netherlands
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21
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Beach LB, Rawson JM, Kim B, Patterson SE, Mansky LM. Novel inhibitors of human immunodeficiency virus type 2 infectivity. J Gen Virol 2014; 95:2778-2783. [PMID: 25103850 DOI: 10.1099/vir.0.069864-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Human immunodeficiency virus type 2 (HIV-2) infects about two million people worldwide. HIV-2 has fewer treatment options than HIV-1, yet may evolve drug resistance more quickly. We have analysed several novel drugs for anti-HIV-2 activity. It was observed that 5-azacytidine, clofarabine, gemcitabine and resveratrol have potent anti-HIV-2 activity. The EC50 values for 5-azacytidine, clofarabine and resveratrol were found to be significantly lower with HIV-2 than with HIV-1. A time-of-addition assay was used to analyse the ability of these drugs to interfere with HIV-2 replication. Reverse transcription was the likely target for antiretroviral activity. Taken together, several novel drugs have been discovered to have activity against HIV-2. Based upon their known activities, these drugs may elicit enhanced HIV-2 mutagenesis and therefore be useful for inducing HIV-2 lethal mutagenesis. In addition, the data are consistent with HIV-2 reverse transcriptase being more sensitive than HIV-1 reverse transcriptase to dNTP pool alterations.
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Affiliation(s)
- Lauren B Beach
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jonathan M Rawson
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Baek Kim
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Steven E Patterson
- Center for Drug Design, University of Minnesota, Minneapolis, MN 55455, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Louis M Mansky
- Center for Drug Design, University of Minnesota, Minneapolis, MN 55455, USA.,Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA
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Nucleoside Analogue Inhibitors of Human Immunodeficiency Virus Reverse Transcriptase. Antiviral Res 2014. [DOI: 10.1128/9781555815493.ch4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Mutations in HIV-1 reverse transcriptase affect the errors made in a single cycle of viral replication. J Virol 2014; 88:7589-601. [PMID: 24760888 DOI: 10.1128/jvi.00302-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED The genetic variation in HIV-1 in patients is due to the high rate of viral replication, the high viral load, and the errors made during viral replication. Some of the mutations in reverse transcriptase (RT) that alter the deoxynucleoside triphosphate (dNTP)-binding pocket, including those that confer resistance to nucleoside/nucleotide analogs, affect dNTP selection during replication. The effects of mutations in RT on the spectrum (nature, position, and frequency) of errors made in vivo are poorly understood. We previously determined the mutation rate and the frequency of different types of mutations and identified hot spots for mutations in a lacZα (the α complementing region of lacZ) reporter gene carried by an HIV-1 vector that replicates using wild-type RT. We show here that four mutations (Y115F, M184V, M184I, and Q151M) in the dNTP-binding pocket of RT that had relatively small effects on the overall HIV-1 mutation rate (less than 3-fold compared to the wild type) significantly increased mutations at some specific positions in the lacZα reporter gene. We also show that changes in a sequence that flanks the reporter gene can affect the mutations that arise in the reporter. These data show that changes either in HIV-1 RT or in the sequence of the nucleic acid template can affect the spectrum of mutations made during viral replication. This could, by implication, affect the generation of drug-resistant mutants and immunological-escape mutants in patients. IMPORTANCE RT is the viral enzyme that converts the RNA genome of HIV into DNA. Errors made during replication allow the virus to escape from the host's immune system and to develop resistance to the available anti-HIV drugs. We show that four different mutations in RT which are known to be associated with resistance to anti-RT drugs modestly increased the overall frequency of errors made during viral replication. However, the increased errors were not uniformly distributed; the additional errors occurred at a small number of positions (hot spots). Moreover, some of the RT mutations preferentially affected the nature of the errors that were made (some RT mutations caused an increase in insertion and deletion errors; others caused an increase in substitution errors). We also show that sequence changes in a region adjacent to a target gene can affect the errors made within the target gene.
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Menéndez-Arias L, Alvarez M. Antiretroviral therapy and drug resistance in human immunodeficiency virus type 2 infection. Antiviral Res 2013; 102:70-86. [PMID: 24345729 DOI: 10.1016/j.antiviral.2013.12.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/02/2013] [Accepted: 12/06/2013] [Indexed: 12/19/2022]
Abstract
One to two million people worldwide are infected with the human immunodeficiency virus type 2 (HIV-2), with highest prevalences in West African countries, but also present in Western Europe, Asia and North America. Compared to HIV-1, HIV-2 infection undergoes a longer asymptomatic phase and progresses to AIDS more slowly. In addition, HIV-2 shows lower transmission rates, probably due to its lower viremia in infected individuals. There is limited experience in the treatment of HIV-2 infection and several antiretroviral drugs used to fight HIV-1 are not effective against HIV-2. Effective drugs against HIV-2 include nucleoside analogue reverse transcriptase (RT) inhibitors (e.g. zidovudine, tenofovir, lamivudine, emtricitabine, abacavir, stavudine and didanosine), protease inhibitors (saquinavir, lopinavir and darunavir), and integrase inhibitors (raltegravir, elvitegravir and dolutegravir). Maraviroc, a CCR5 antagonist blocking coreceptor binding during HIV entry, is active in vitro against CCR5-tropic HIV-2 but more studies are needed to validate its use in therapeutic treatments against HIV-2 infection. HIV-2 strains are naturally resistant to a few antiretroviral drugs developed to suppress HIV-1 propagation such as nonnucleoside RT inhibitors, several protease inhibitors and the fusion inhibitor enfuvirtide. Resistance selection in HIV-2 appears to be faster than in HIV-1. In this scenario, the development of novel drugs specific for HIV-2 is an important priority. In this review, we discuss current anti-HIV-2 therapies and mutational pathways leading to drug resistance.
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Affiliation(s)
- Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Mar Alvarez
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain
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[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]. Enferm Infecc Microbiol Clin 2013; 31:602.e1-602.e98. [PMID: 24161378 DOI: 10.1016/j.eimc.2013.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 04/08/2013] [Indexed: 02/08/2023]
Abstract
OBJECTIVE This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients. METHODS To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America. RESULTS cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis. CONCLUSIONS These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.
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[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]. Enferm Infecc Microbiol Clin 2012; 30:e1-89. [PMID: 22633764 DOI: 10.1016/j.eimc.2012.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 03/19/2012] [Indexed: 11/20/2022]
Abstract
This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.
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HIV-1 and HIV-2 reverse transcriptases: different mechanisms of resistance to nucleoside reverse transcriptase inhibitors. J Virol 2012; 86:5885-94. [PMID: 22438533 DOI: 10.1128/jvi.06597-11] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
As anti-HIV therapy becomes more widely available in developing nations, it is clear that drug resistance will continue to be a major problem. The related viruses HIV-1 and HIV-2 share many of the same resistance pathways to nucleoside reverse transcriptase inhibitors (NRTIs). However, clinical data suggest that while HIV-1 reverse transcriptase (RT) usually uses an ATP-dependent excision pathway to develop resistance to the nucleoside analog zidovudine (AZT), HIV-2 RT does not appear to use this pathway. We previously described data that suggested that wild-type (WT) HIV-2 RT has a much lower ability to excise AZT monophosphate (AZTMP) than does WT HIV-1 RT and suggested that this is the reason that HIV-2 RT more readily adopts an exclusion pathway against AZT triphosphate (AZTTP), while HIV-1 RT is better able to exploit the ATP-dependent pyrophosphorolysis mechanism. However, we have now done additional experiments, which show that while HIV-1 RT can adopt either an exclusion- or excision-based resistance mechanism against AZT, HIV-2 RT can use only the exclusion mechanism. All of our attempts to make HIV-2 RT excision competent did not produce an AZT-resistant RT but instead yielded RTs that were less able to polymerize than the WT. This suggests that the exclusion pathway is the only pathway available to HIV-2.
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Ndongwe TP, Adedeji AO, Michailidis E, Ong YT, Hachiya A, Marchand B, Ryan EM, Rai DK, Kirby KA, Whatley AS, Burke DH, Johnson M, Ding S, Zheng YM, Liu SL, Kodama EI, Delviks-Frankenberry KA, Pathak VK, Mitsuya H, Parniak MA, Singh K, Sarafianos SG. Biochemical, inhibition and inhibitor resistance studies of xenotropic murine leukemia virus-related virus reverse transcriptase. Nucleic Acids Res 2011; 40:345-59. [PMID: 21908397 PMCID: PMC3245923 DOI: 10.1093/nar/gkr694] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We report key mechanistic differences between the reverse transcriptases (RT) of human immunodeficiency virus type-1 (HIV-1) and of xenotropic murine leukemia virus-related virus (XMRV), a gammaretrovirus that can infect human cells. Steady and pre-steady state kinetics demonstrated that XMRV RT is significantly less efficient in DNA synthesis and in unblocking chain-terminated primers. Surface plasmon resonance experiments showed that the gammaretroviral enzyme has a remarkably higher dissociation rate (koff) from DNA, which also results in lower processivity than HIV-1 RT. Transient kinetics of mismatch incorporation revealed that XMRV RT has higher fidelity than HIV-1 RT. We identified RNA aptamers that potently inhibit XMRV, but not HIV-1 RT. XMRV RT is highly susceptible to some nucleoside RT inhibitors, including Translocation Deficient RT inhibitors, but not to non-nucleoside RT inhibitors. We demonstrated that XMRV RT mutants K103R and Q190M, which are equivalent to HIV-1 mutants that are resistant to tenofovir (K65R) and AZT (Q151M), are also resistant to the respective drugs, suggesting that XMRV can acquire resistance to these compounds through the decreased incorporation mechanism reported in HIV-1.
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Affiliation(s)
- Tanyaradzwa P Ndongwe
- Christopher Bond Life Sciences Center, Department of Molecular Microbiology & Immunology, University of Missouri, School of Medicine, Columbia, MO 65211, USA
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Benard A, van Sighem A, Taieb A, Valadas E, Ruelle J, Soriano V, Calmy A, Balotta C, Damond F, Brun-Vezinet F, Chene G, Matheron S. Immunovirological response to triple nucleotide reverse-transcriptase inhibitors and ritonavir-boosted protease inhibitors in treatment-naive HIV-2-infected patients: The ACHIEV2E Collaboration Study Group. Clin Infect Dis 2011; 52:1257-66. [PMID: 21507923 DOI: 10.1093/cid/cir123] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Triple nucleoside reverse-transcriptase inhibitors (NRTIs) are recommended by the World Health Organization as first-line regimen in treatment-naïve HIV-2-infected patients. However, ritonavir-boosted protease inhibitor (PI/r)-containing regimens are frequently prescribed. In the absence of previous randomized trials, we retrospectively compared these regimens in observational cohorts. METHODS HIV-2-infected patients from 7 European cohorts who started triple NRTI or PI/r since January 1998 were included. Piecewise linear models were used to estimate CD4 cell count and plasma HIV-2 RNA level slopes, differentiating an early phase (until end of month 3) and a second phase (months 4-12). On-treatment analyses censored data at major treatment modification and systematically at month 12. RESULTS Forty-four patients started triple NRTI therapy and 126 started PI/r therapy. Overall, the median CD4 cell count was 191 cells/mm(3) and the median plasma HIV-2 RNA level was ≥2.7 log(10) copies/ml in 61% of the patients at combination antiretroviral therapy (cART) initiation; the median duration of the first cART was 20 months, not differing between groups. PI/r regimens were associated with better CD4 cell count and HIV-2 RNA level outcomes, compared with NRTI regimens. Estimated CD4 cell count slopes were +6 and +12 cells/mm(3)/month during the early phase (P = .22), and -60 cells/mm(3)/year versus +76 cells/mm(3)/year during the second phase (P = .002), for triple NRTI and PI/r, respectively. Estimated mean HIV-2 RNA levels at month 12 in patients with detectable viremia at cART initiation were 4.0 and 2.2 log(10) copies/ml, respectively (P = .005). CONCLUSIONS In this observational study, PI/r-containing regimens showed superior efficacy over triple NRTI regimens as first-line therapy in HIV-2-infected patients.
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Ibe S, Sugiura W. Clinical significance of HIV reverse-transcriptase inhibitor-resistance mutations. Future Microbiol 2011; 6:295-315. [PMID: 21449841 DOI: 10.2217/fmb.11.7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In this article, we summarize recent knowledge on drug-resistance mutations within HIV reverse transcriptase (RT). Several large-scale HIV-1 genotypic analyses have revealed that the most prevalent nucleos(t)ide analog RT inhibitor (NRTI)-resistance mutation is M184V/I followed by a series of thymidine analog-associated mutations: M41L, D67N, K70R, L210W, T215Y/F and K219Q/E. Among non-nucleoside RT inhibitor (NNRTI)-resistance mutations, K103N was frequently observed, followed by Y181C and G190A. Interestingly, V106M was identified in HIV-1 subtype C as a subtype-specific multi-NNRTI-resistance mutation. Regarding mutations in the HIV-1 RT C-terminal region, including the connection subdomain and RNase H domain, their clinical impacts are still controversial, although their effects on NRTI and NNRTI resistance have been confirmed in vitro. In HIV-2 infections, the high prevalence of the Q151M mutation associated with multi-NRTI resistance has been frequently observed.
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Affiliation(s)
- Shiro Ibe
- Department of Infection & Immunology, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan
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HIV-2 integrase variation in integrase inhibitor-naïve adults in Senegal, West Africa. PLoS One 2011; 6:e22204. [PMID: 21765953 PMCID: PMC3134476 DOI: 10.1371/journal.pone.0022204] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 06/16/2011] [Indexed: 11/19/2022] Open
Abstract
Background Antiretroviral therapy for HIV-2 infection is hampered by intrinsic resistance to many of the drugs used to treat HIV-1. Limited studies suggest that the integrase inhibitors (INIs) raltegravir and elvitegravir have potent activity against HIV-2 in culture and in infected patients. There is a paucity of data on genotypic variation in HIV-2 integrase that might confer intrinsic or transmitted INI resistance. Methods We PCR amplified and analyzed 122 HIV-2 integrase consensus sequences from 39 HIV-2–infected, INI-naive adults in Senegal, West Africa. We assessed genetic variation and canonical mutations known to confer INI-resistance in HIV-1. Results No amino acid-altering mutations were detected at sites known to be pivotal for INI resistance in HIV-1 (integrase positions 143, 148 and 155). Polymorphisms at several other HIV-1 INI resistance-associated sites were detected at positions 72, 95, 125, 154, 165, 201, 203, and 263 of the HIV-2 integrase protein. Conclusion Emerging genotypic and phenotypic data suggest that HIV-2 is susceptible to the new class of HIV integrase inhibitors. We hypothesize that intrinsic HIV-2 integrase variation at “secondary” HIV-1 INI-resistance sites may affect the genetic barrier to HIV-2 INI resistance. Further studies will be needed to assess INI efficacy as part of combination antiretroviral therapy in HIV-2–infected patients.
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Martínez JP, Bocharov G, Ignatovich A, Reiter J, Dittmar MT, Wain-Hobson S, Meyerhans A. Fitness ranking of individual mutants drives patterns of epistatic interactions in HIV-1. PLoS One 2011; 6:e18375. [PMID: 21483787 PMCID: PMC3069090 DOI: 10.1371/journal.pone.0018375] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 02/28/2011] [Indexed: 11/19/2022] Open
Abstract
Fitness interactions between mutations, referred to as epistasis, can strongly impact evolution. For RNA viruses and retroviruses with their high mutation rates, epistasis may be particularly important to overcome fitness losses due to the accumulation of deleterious mutations and thus could influence the frequency of mutants in a viral population. As human immunodeficiency virus type 1 (HIV-1) resistance to azidothymidine (AZT) requires selection of sequential mutations, it is a good system to study the impact of epistasis. Here we present a thorough analysis of a classical AZT-resistance pathway (the 41–215 cluster) of HIV-1 variants by fitness measurements in single round infection assays covering physiological drug concentrations ex vivo. The sign and value of epistasis varied and did not predict the epistatic effect on the mutant frequency. This complex behavior is explained by the fitness ranking of the variants that strongly depends on environmental factors, i.e., the presence and absence of drugs and the host cells used. Although some interactions compensate fitness losses, the observed small effect on the relative mutant frequencies suggests that epistasis might be inefficient as a buffering mechanism for fitness losses in vivo. While the use of epistasis-based hypotheses to make general assumptions on the evolutionary dynamics of viral populations is appealing, our data caution their interpretation without further knowledge on the characteristics of the viral mutant spectrum under different environmental conditions.
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Affiliation(s)
| | - Gennady Bocharov
- Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Anna Ignatovich
- Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russian Federation
| | - Jochen Reiter
- Department of Virology, University of the Saarland, Homburg, Germany
| | - Matthias T. Dittmar
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, London, United Kingdom
| | | | - Andreas Meyerhans
- Department of Virology, University of the Saarland, Homburg, Germany
- ICREA Infection Biology Laboratory, Department of Experimental and Health Sciences, University Pompeu Fabra, Barcelona, Spain
- * E-mail:
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Herschhorn A, Hizi A. Retroviral reverse transcriptases. Cell Mol Life Sci 2010; 67:2717-47. [PMID: 20358252 PMCID: PMC11115783 DOI: 10.1007/s00018-010-0346-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 02/22/2010] [Accepted: 03/08/2010] [Indexed: 12/22/2022]
Abstract
Reverse transcription is a critical step in the life cycle of all retroviruses and related retrotransposons. This complex process is performed exclusively by the retroviral reverse transcriptase (RT) enzyme that converts the viral single-stranded RNA into integration-competent double-stranded DNA. Although all RTs have similar catalytic activities, they significantly differ in several aspects of their catalytic properties, their structures and subunit composition. The RT of human immunodeficiency virus type-1 (HIV-1), the virus causing acquired immunodeficiency syndrome (AIDS), is a prime target for the development of antiretroviral drug therapy of HIV-1/AIDS carriers. Therefore, despite the fundamental contributions of other RTs to the understanding of RTs and retrovirology, most recent RT studies are related to HIV-1 RT. In this review we summarize the basic properties of different RTs. These include, among other topics, their structures, enzymatic activities, interactions with both viral and host proteins, RT inhibition and resistance to antiretroviral drugs.
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Affiliation(s)
- Alon Herschhorn
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Amnon Hizi
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
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Saeng-aroon S, Tsuchiya N, Auwanit W, Ayuthaya PIN, Pathipvanich P, Sawanpanyalert P, Rojanawiwat A, Kannagi M, Ariyoshi K, Sugiura W. Drug-resistant mutation patterns in CRF01_AE cases that failed d4T+3TC+nevirapine fixed-dosed, combination treatment: Follow-up study from the Lampang cohort. Antiviral Res 2010; 87:22-9. [DOI: 10.1016/j.antiviral.2010.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 03/25/2010] [Accepted: 04/01/2010] [Indexed: 10/19/2022]
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Abstract
HIV-1 Reverse Transcriptase (HIV-1 RT) has been the target of numerous approved anti-AIDS drugs that are key components of Highly Active Anti-Retroviral Therapies (HAART). It remains the target of extensive structural studies that continue unabated for almost twenty years. The crystal structures of wild-type or drug-resistant mutant HIV RTs in the unliganded form or in complex with substrates and/or drugs have offered valuable glimpses into the enzyme’s folding and its interactions with DNA and dNTP substrates, as well as with nucleos(t)ide reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTIs) drugs. These studies have been used to interpret a large body of biochemical results and have paved the way for innovative biochemical experiments designed to elucidate the mechanisms of catalysis and drug inhibition of polymerase and RNase H functions of RT. In turn, the combined use of structural biology and biochemical approaches has led to the discovery of novel mechanisms of drug resistance and has contributed to the design of new drugs with improved potency and ability to suppress multi-drug resistant strains.
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Mechanisms of resistance associated with excision of incorporated nucleotide analogue inhibitors of HIV-1 reverse transcriptase. Curr Opin HIV AIDS 2009; 2:103-7. [PMID: 19372874 DOI: 10.1097/coh.0b013e3280287a60] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW Nucleoside analogue reverse transcriptase inhibitors are important components in current drug regimens used to treat infection with HIV. Despite the potency of drug combinations that involve two nucleoside reverse transcriptase inhibitors and a non-nucleoside analogue or a protease inhibitor, the emergence of resistance remains a major reason for treatment failure. This article reviews biochemical mechanisms associated with resistance to nucleoside reverse transcriptase inhibitors. RECENT FINDINGS The thymidine analogues zidovudine and stavudine select for mutational patterns that facilitate the phosphorolytic excision of literally all available nucleoside reverse transcriptase inhibitors. Major progress has been made in defining genotypes that either support or counteract the reaction. Thymidine analogue-associated mutations were shown to increase rates of excision. In contrast, non-thymidine analogue reverse transcriptase inhibitors select for different mutations, e.g. M184V, L74V, and K65R that diminish the effects of thymidine analogue-associated mutations. Possible underlying biochemical mechanisms are discussed in this review. SUMMARY The non-thymidine analogue-associated mutations M184V, L74V, and K65R show incompatibilities with thymidine-analogue-associated mutations. Maximizing these effects in clinical practice may help delay the emergence of resistance. Together, the clinical and biochemical data validate the excision reaction as a target for the development of novel compounds that interfere with the reaction.
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Matamoros T, Nevot M, Martínez MA, Menéndez-Arias L. Thymidine analogue resistance suppression by V75I of HIV-1 reverse transcriptase: effects of substituting valine 75 on stavudine excision and discrimination. J Biol Chem 2009; 284:32792-802. [PMID: 19801659 DOI: 10.1074/jbc.m109.038885] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Val(75) of HIV-1 reverse transcriptase (RT) plays a role in positioning the template nucleotide +1 during the formation of the ternary complex. Mutations, such as V75M and V75A, emerge in patients infected with HIV-1 group M subtype B and group O variants, after failing treatment with stavudine (d4T) and other nucleoside RT inhibitors. V75I is an accessory mutation of the Q151M multidrug resistance complex of HIV-1 RT and is rarely associated with thymidine analogue resistance mutations (TAMs). In vitro, it confers resistance to acyclovir. TAMs confer resistance to zidovudine (AZT) and d4T by increasing the rate of ATP-mediated excision of the terminal nucleotide monophosphate (primer unblocking). In a wild-type HIV-1 group O RT sequence context, V75A and V75M conferred increased excision activity on d4T-terminated primers, in the presence of PP(i). In contrast, V75I decreased the PP(i)-mediated unblocking efficiency on AZT and d4T-terminated primers, in different sequence contexts (i.e. wild-type group M subtype B or group O RTs). Interestingly, in the sequence context of an excision-proficient RT (i.e. M41L/A62V/T69SSS/K70R/T215Y), the introduction of V75I led to a significant decrease of its ATP-dependent excision activity on AZT-, d4T-, and acyclovir-terminated primers. The excision rate of d4T-monophosphate in the presence of ATP (3.2 mm) was about 10 times higher for M41L/A62V/T69SSS/K70R/T215Y than for the mutant M41L/A62V/T69SSS/K70R/V75I/T215Y RT. The antagonistic effect of V75I with TAMs was further demonstrated in phenotypic assays. Recombinant HIV-1 containing the M41L/A62V/T69SSS/K70R/V75I/T215Y RT showed 18.3- and 1.5-fold increased susceptibility to AZT and d4T, respectively, in comparison with virus containing the M41L/A62V/T69SSS/K70R/T215Y RT.
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Affiliation(s)
- Tania Matamoros
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, Campus de Cantoblanco, 28049 Madrid, Spain
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Ntemgwa ML, d'Aquin Toni T, Brenner BG, Camacho RJ, Wainberg MA. Antiretroviral drug resistance in human immunodeficiency virus type 2. Antimicrob Agents Chemother 2009; 53:3611-9. [PMID: 19470514 PMCID: PMC2737883 DOI: 10.1128/aac.00154-09] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Michel L Ntemgwa
- McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
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Smith RA, Anderson DJ, Pyrak CL, Preston BD, Gottlieb GS. Antiretroviral drug resistance in HIV-2: three amino acid changes are sufficient for classwide nucleoside analogue resistance. J Infect Dis 2009; 199:1323-6. [PMID: 19358668 DOI: 10.1086/597802] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Genotypic surveys suggest that human immunodeficiency virus type 1 (HIV-1) and HIV-2 evolve different sets of mutations in response to nucleoside reverse-transcriptase inhibitors (NRTIs). We used site-directed mutagenesis, culture-based phenotyping, and cell-free assays to determine the resistance profiles conferred by specific amino acid replacements in HIV-2 reverse transcriptase. Although thymidine analogue mutations had no effect on zidovudine sensitivity, the addition of Q151M together with K65R or M184V was sufficient for high-level resistance to both lamivudine and zidovudine in HIV-2, and the combination of K65R, Q151M, and M184V conferred classwide NRTI resistance. These data suggest that current NRTI-based regimens are suboptimal for treating HIV-2 infection.
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Affiliation(s)
- Robert A Smith
- Department of Pathology, Division of Allergy and Infectious Diseases, University of Washington, Seattle, WA 98133, USA.
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Nucleoside and nucleotide analogs select in culture for different patterns of drug resistance in human immunodeficiency virus types 1 and 2. Antimicrob Agents Chemother 2008; 53:708-15. [PMID: 19064892 DOI: 10.1128/aac.01109-08] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent findings suggest bidirectional antagonisms between the K65R mutation and thymidine analogue mutations in human immunodeficiency virus type 1 (HIV-1)-infected, treatment-experienced patients, yet little is known about HIV-2 in this regard. This study addressed the effects of innate polymorphisms in HIV-2 on emergent resistance to nucleoside/nucleotide analogues. Emergent drug resistance profiles in HIV-2 subtypes A (n = 3) and B (n = 1) were compared to those of HIV-1 subtypes B and C. Drug resistance was evaluated with cord blood mononuclear cells (CBMCs) and MT2 cells, using selective pressure with tenofovir (TFV), zidovudine (ZDV), stavudine (d4T), didanosine (ddI), abacavir (ABC), lamivudine (3TC), emtricitabine (FTC), or various dual-drug combinations. Resistance was evaluated using conventional and ultrasensitive sequencing approaches. In agreement with our previous findings, dual-drug combinations of TFV, ddI, ABC, d4T, ZDV, and 3TC preferentially selected for K65R in HIV-1 subtype C isolates. In HIV-1 subtype B, TFV-3TC and ZDV-3TC selected for M184I and D67N, respectively. In contrast, selections with all four HIV-2 cultures favored the development of M184I in dual-drug combinations that included either 3TC or FTC. Since HIV-2 cultures did not develop K65R, an ultrasensitive allele-specific real-time PCR assay was developed to distinguish the presence of 65R from wild-type K65 after 16 cycles with a discriminatory ability of 0.1% against a population of wild-type virus. These results underscore potential differences in emergent drug resistance pathways in HIV-1 and HIV-2 and show that polymorphisms may influence the development of the resistance pathways that are likely to emerge.
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de Silva TI, Cotten M, Rowland-Jones SL. HIV-2: the forgotten AIDS virus. Trends Microbiol 2008; 16:588-95. [PMID: 18964021 DOI: 10.1016/j.tim.2008.09.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/16/2008] [Accepted: 09/18/2008] [Indexed: 10/21/2022]
Abstract
HIV type 2 (HIV-2), a closely related retrovirus discovered a few years after HIV type 1, causes AIDS in only a minority of infected individuals. Determining why HIV-2 causes asymptomatic infection in most patients could further our understanding of HIV immunopathogenesis. Studies to date have suggested that both enhanced immune responses and lower viral replication could play a role. We summarize the important findings to date and highlight areas that warrant further exploration.
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Affiliation(s)
- Thushan I de Silva
- Medical Research Council Laboratories, Atlantic Road, PO Box 273, Fajara, The Gambia, West Africa.
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A call for randomized controlled trials of antiretroviral therapy for HIV-2 infection in West Africa. AIDS 2008; 22:2069-72; discussion 2073-4. [PMID: 18832869 DOI: 10.1097/qad.0b013e32830edd44] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Baseline resistance of primary human immunodeficiency virus type 1 strains to the CXCR4 inhibitor AMD3100. J Virol 2008; 82:11695-704. [PMID: 18799588 DOI: 10.1128/jvi.01303-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We screened a panel of R5X4 and X4 human immunodeficiency virus type 1 (HIV-1) strains for their sensitivities to AMD3100, a small-molecule CXCR4 antagonist that blocks HIV-1 infection via this coreceptor. While no longer under clinical development, AMD3100 is a useful tool with which to probe interactions between the viral envelope (Env) protein and CXCR4 and to identify pathways by which HIV-1 may become resistant to this class of antiviral agents. While infection by most virus strains was completely blocked by AMD3100, we identified several R5X4 and X4 isolates that exhibited plateau effects: as the AMD3100 concentration was increased, virus infection and membrane fusion diminished to variable degrees. Once saturating concentrations of AMD3100 were achieved, further inhibition was not observed, indicating a noncompetitive mode of viral resistance to the drug. The magnitude of the plateau varied depending on the virus isolate, as well as the cell type used, with considerable variation observed when primary human T cells from different human donors were used. Structure-function studies indicated that the V1/V2 region of the R5X4 HIV-1 isolate DH12 was necessary for AMD3100 resistance and could confer this property on two heterologous Env proteins. We conclude that some R5X4 and X4 HIV-1 isolates can utilize the AMD3100-bound conformation of CXCR4, with the efficiency being influenced by both viral and host factors. Baseline resistance to this CXCR4 antagonist could influence the clinical use of such compounds.
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Hizi A, Herschhorn A. Retroviral reverse transcriptases (other than those of HIV-1 and murine leukemia virus): a comparison of their molecular and biochemical properties. Virus Res 2008; 134:203-20. [PMID: 18291546 DOI: 10.1016/j.virusres.2007.12.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 12/16/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
Abstract
This chapter reviews most of the biochemical data on reverse transcriptases (RTs) of retroviruses, other than those of HIV-1 and murine leukemia virus (MLV) that are covered in detail in other reviews of this special edition devoted to reverse transcriptases. The various RTs mentioned are grouped according to their retroviral origins and include the RTs of the alpharetroviruses, lentiviruses (both primate, other than HIV-1, and non-primate lentiviruses), betaretroviruses, deltaretroviruses and spumaretroviruses. For each RT group, the processing, molecular organization as well as the enzymatic activities and biochemical properties are described. Several RTs function as dimers, primarily as heterodimers, while the others are active as monomeric proteins. The comparisons between the diverse properties of the various RTs show the common traits that characterize the RTs from all retroviral subfamilies. In addition, the unique features of the specific RTs groups are also discussed.
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Affiliation(s)
- Amnon Hizi
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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Comparison of viro-immunological marker changes between HIV-1 and HIV-2-infected patients in France. AIDS 2008; 22:457-68. [PMID: 18301058 DOI: 10.1097/qad.0b013e3282f4ddfc] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND HIV-2 is known to be less pathogenic than HIV-1, although the underlying mechanisms are still debated. We compared the changes over time in viro-immunological markers in HIV-1 and HIV-2-infected patients living in France during natural history and after initiation of the first combination antiretroviral therapy (CART). METHOD Patients were included in the ANRS CO3 HIV-1 cohort (N = 6707) or the ANRS CO5 HIV-2 cohort (N = 572). HIV-1-infected patients were matched to HIV-2 patients according to sex, age, HIV transmission group and period of treatment initiation. Changes in markers were estimated using linear mixed models. RESULTS Analyses were performed for three groups of patients: those with estimated date of contamination (98 HIV-1 and 49 HIV-2-seroincident patients); untreated seroprevalent patients (320 HIV-1 and 160 HIV-2); and those initiating a first CART (59 HIV-1 and 63 HIV-2). In group 1, CD4 T-cell counts decreased less rapidly in HIV-2 than HIV-1 patients (-9 versus -49 cells/microl per year, P < 10(-4)). Results were similar in group 2. Baseline CD4 cell count at CART initiation was not different according to the type of infection. During the first 2 months of treatment, the CD4 cell count increased by +59 cells/microl per month (CI 34; 84) for HIV-1 and +24 (CI 6; 42) for HIV-2. The plasma viral load drop was threefold more important in HIV-1 patients: -1.56 log10/ml per month versus -0.62 among HIV-2 patients (P < 10(-4)). CONCLUSION Differences between the two infections during natural history are similar to those previously described in Africa. Once treatment is started, response is poorer in HIV-2 than in HIV-1 patients.
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Menéndez-Arias L. Mechanisms of resistance to nucleoside analogue inhibitors of HIV-1 reverse transcriptase. Virus Res 2008; 134:124-46. [PMID: 18272247 DOI: 10.1016/j.virusres.2007.12.015] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 12/21/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
Human immunodeficiency virus (HIV) reverse transcriptase (RT) inhibitors can be classified into nucleoside and nonnucleoside RT inhibitors. Nucleoside RT inhibitors are converted to active triphosphate analogues and incorporated into the DNA in RT-catalyzed reactions. They act as chain terminators blocking DNA synthesis, since they lack the 3'-OH group required for the phosphodiester bond formation. Unfortunately, available therapies do not completely suppress viral replication, and the emergence of drug-resistant HIV variants is facilitated by the high adaptation capacity of the virus. Mutations in the RT-coding region selected during treatment with nucleoside analogues confer resistance through different mechanisms: (i) altering discrimination between nucleoside RT inhibitors and natural substrates (dNTPs) (e.g. Q151M, M184V, etc.), or (ii) increasing the RT's phosphorolytic activity (e.g. M41L, T215Y and other thymidine analogue resistance mutations), which in the presence of a pyrophosphate donor (usually ATP) allow the removal of chain-terminating inhibitors from the 3' end of the primer. Both mechanisms are implicated in multi-drug resistance. The excision reaction can be modulated by mutations conferring resistance to nucleoside or nonnucleoside RT inhibitors, and by amino acid substitutions that interfere with the proper binding of the template-primer, including mutations that affect RNase H activity. New developments in the field should contribute towards improving the efficacy of current therapies.
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Affiliation(s)
- Luis Menéndez-Arias
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Nicolás Cabrera, 1, Campus de Cantoblanco, 28049 Madrid, Spain.
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Smith RA, Gottlieb GS, Anderson DJ, Pyrak CL, Preston BD. Human immunodeficiency virus types 1 and 2 exhibit comparable sensitivities to Zidovudine and other nucleoside analog inhibitors in vitro. Antimicrob Agents Chemother 2008; 52:329-32. [PMID: 17967913 PMCID: PMC2223890 DOI: 10.1128/aac.01004-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/14/2007] [Accepted: 10/23/2007] [Indexed: 11/20/2022] Open
Abstract
Using an indicator cell assay that directly quantifies viral replication, we show that human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2, respectively) exhibit similar sensitivities to 3'-azido-3'-deoxythymidine (zidovudine) as well as other nucleoside analog inhibitors of reverse transcriptase. These data support the use of nucleoside analogs for antiviral therapy of HIV-2 infection.
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Affiliation(s)
- Robert A Smith
- University of Washington, Department of Pathology, K-046 HSB, Box 357705, 1959 NE Pacific St., Seattle, WA 98195, USA.
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Hartl MJ, Kretzschmar B, Frohn A, Nowrouzi A, Rethwilm A, Wöhrl BM. AZT resistance of simian foamy virus reverse transcriptase is based on the excision of AZTMP in the presence of ATP. Nucleic Acids Res 2007; 36:1009-16. [PMID: 18096624 PMCID: PMC2241919 DOI: 10.1093/nar/gkm1087] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Azidothymidine (AZT, zidovudine) is one of the few nucleoside inhibitors known to inhibit foamy virus replication. We have shown previously that up to four mutations in the reverse transcriptase gene of simian foamy virus from macaque (SFVmac) are necessary to confer high resistance against AZT. To characterize the mechanism of AZT resistance we expressed two recombinant reverse transcriptases of highly AZT-resistant SFVmac in Escherichia coli harboring three (K211I, S345T, E350K) or four mutations (K211I, I224T, S345T, E350K) in the reverse transcriptase gene. Our analyses show that the polymerization activity of these mutants is impaired. In contrast to the AZT-resistant reverse transcriptase of HIV-1, the AZT resistant enzymes of SFVmac reveal differences in their kinetic properties. The SFVmac enzymes exhibit lower specific activities on poly(rA)/oligo(dT) and higher KM-values for polymerization but no change in KD-values for DNA/DNA or RNA/DNA substrates. The AZT resistance of the mutant enzymes is based on the excision of the incorporated inhibitor in the presence of ATP. The additional amino acid change of the quadruple mutant appears to be important for regaining polymerization efficiency.
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Affiliation(s)
- Maximilian J Hartl
- Universität Bayreuth, Lehrstuhl für Struktur und Chemie der Biopolymere & Research Center for Biomacromolecules, 95440 Bayreuth, Germany
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Fox ZV, Geretti AM, Kjaer J, Dragsted UB, Phillips AN, Gerstoft J, Staszewski S, Clotet B, von Wyl V, Lundgren JD. The ability of four genotypic interpretation systems to predict virological response to ritonavir-boosted protease inhibitors. AIDS 2007; 21:2033-42. [PMID: 17885293 DOI: 10.1097/qad.0b013e32825a69e4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND : Limited information exists on the prognostic value of genotypic interpretation systems (GISs) for ritonavir-boosted protease inhibitors (PI/rs). We compared PI/r resistance levels ascribed by four GIS and examined their abilities to predict HIV-RNA reductions after starting a PI/r-based regimen (baseline). METHODS : Data on viraemic (HIV-RNA > 500 copies/ml) patients starting a PI/r with a baseline resistance test were combined from an observational cohort study (EuroSIDA) and three randomized trials (MaxCmin1; MaxCmin2 and COLATE). The GIS surveyed were ANRS, DMC, REGA and Stanford. Factors associated with HIV-RNA change were identified through censored regression analysis. RESULTS : We included 744 patients, of whom 67% were PI experienced. At baseline 12-28% (depending on the GIS) patients had a virus with predicted resistance/intermediate resistance to the PI/r initiated. Concordance between GISs on ascribed PI/r resistance levels was moderate: kappa values ranged from 0.01 to 1.00, with the lowest kappas seen for amprenavir. The median (interquartile range) baseline HIV-RNA was 4.4 (3.5-5.1) log10 and was reduced by 2.2 (2.1-2.3) log10 12 (9-13) weeks after baseline. GIS consistently showed greater HIV-RNA reductions as the ascribed level of sensitivity to the PI/r increased. Conversely, the number of other active drugs in the rest of the regimen, according to each GIS did not predict HIV-RNA reductions consistently. CONCLUSION : Despite large variations in how GIS classify HIV susceptibility to PI/r, all GIS predicted HIV-RNA reductions of a similar magnitude. The ascribed level of susceptibility to other drugs in the regimen did not predict HIV-RNA decline.
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Affiliation(s)
- Zoe V Fox
- Copenhagen HIV Programme, Medical Faculty at University of Copenhagen, Denmark.
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Kretzschmar B, Nowrouzi A, Hartl MJ, Gärtner K, Wiktorowicz T, Herchenröder O, Kanzler S, Rudolph W, Mergia A, Wöhrl B, Rethwilm A. AZT-resistant foamy virus. Virology 2007; 370:151-7. [PMID: 17904181 PMCID: PMC2276251 DOI: 10.1016/j.virol.2007.08.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 07/25/2007] [Accepted: 08/21/2007] [Indexed: 11/24/2022]
Abstract
Azidothymidine (AZT) is a reverse transcriptase (RT) inhibitor that efficiently blocks the replication of spumaretroviruses or foamy viruses (FVs). To more precisely elucidate the mechanism of action of the FV RT enzyme, we generated an AZT-resistant FV in cell culture. Biologically resistant virus was obtained for simian foamy virus from macaque (SFVmac), which was insensitive to AZT concentrations of 1 mM, but not for FVs derived from chimpanzees. Nucleotide sequencing revealed four non-silent mutations in the pol gene. Introduction of these mutations into an infectious molecular clone identified all changes to be required for the fully AZT-resistant phenotype of SFVmac. The alteration of individual sites showed that AZT resistance in SFVmac was likely acquired by consecutive acquisition of pol mutations in a defined order, because some alterations on their own did not result in an efficiently replicating virus, neither in the presence nor in the absence of AZT. The introduction of the mutations into the RT of the closely related prototypic FV (PFV) did not yield an AZT-resistant virus, instead they significantly impaired the viral fitness.
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Affiliation(s)
- Benedikt Kretzschmar
- Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany
| | - Ali Nowrouzi
- Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany
| | | | - Kathleen Gärtner
- Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany
| | - Tatiana Wiktorowicz
- Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany
| | - Ottmar Herchenröder
- Technische Universität Dresden, Medizinische Fakultät “Carl Gustav Carus,” Institut für Virologie, Dresden, Germany
| | - Sylvia Kanzler
- Technische Universität Dresden, Medizinische Fakultät “Carl Gustav Carus,” Institut für Virologie, Dresden, Germany
| | - Wolfram Rudolph
- Technische Universität Dresden, Medizinische Fakultät “Carl Gustav Carus,” Institut für Virologie, Dresden, Germany
| | - Ayalew Mergia
- Department of Infectious Disease and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Birgitta Wöhrl
- Universität Bayreuth, Lehrstuhl Biopolymere, Bayreuth, Germany
| | - Axel Rethwilm
- Universität Würzburg, Institut für Virologie und Immunbiologie, Versbacher Str. 7, 97078 Würzburg, Germany
- Corresponding author. Fax: +49 931 201 49553. E-mail address: (A. Rethwilm)
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