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Ling L, Leda AR, Begum N, Spagnuolo RA, Wahl A, Garcia JV, Valente ST. Loss of In Vivo Replication Fitness of HIV-1 Variants Resistant to the Tat Inhibitor, dCA. Viruses 2023; 15:950. [PMID: 37112931 PMCID: PMC10146675 DOI: 10.3390/v15040950] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/29/2023] [Accepted: 04/01/2023] [Indexed: 04/29/2023] Open
Abstract
HIV resistance to the Tat inhibitor didehydro-cortistatin A (dCA) in vitro correlates with higher levels of Tat-independent viral transcription and a seeming inability to enter latency, which rendered resistant isolates more susceptible to CTL-mediated immune clearance. Here, we investigated the ability of dCA-resistant viruses to replicate in vivo using a humanized mouse model of HIV infection. Animals were infected with WT or two dCA-resistant HIV-1 isolates in the absence of dCA and followed for 5 weeks. dCA-resistant viruses exhibited lower replication rates compared to WT. Viral replication was suppressed early after infection, with viral emergence at later time points. Multiplex analysis of cytokine and chemokines from plasma samples early after infection revealed no differences in expression levels between groups, suggesting that dCA-resistance viruses did not elicit potent innate immune responses capable of blocking the establishment of infection. Viral single genome sequencing results from plasma samples collected at euthanasia revealed that at least half of the total number of mutations in the LTR region of the HIV genome considered essential for dCA evasion reverted to WT. These results suggest that dCA-resistant viruses identified in vitro suffer a fitness cost in vivo, with mutations in LTR and Nef pressured to revert to wild type.
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Affiliation(s)
- Lijun Ling
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ana R. Leda
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL 33458, USA
| | - Nurjahan Begum
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rae Ann Spagnuolo
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Angela Wahl
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - J. Victor Garcia
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Susana T. Valente
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL 33458, USA
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2
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Rodriguez-Irizarry VJ, Schneider AC, Ahle D, Smith JM, Suarez-Martinez EB, Salazar EA, McDaniel Mims B, Rasha F, Moussa H, Moustaïd-Moussa N, Pruitt K, Fonseca M, Henriquez M, Clauss MA, Grisham MB, Almodovar S. Mice with humanized immune system as novel models to study HIV-associated pulmonary hypertension. Front Immunol 2022; 13:936164. [PMID: 35990658 PMCID: PMC9390008 DOI: 10.3389/fimmu.2022.936164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/19/2022] [Indexed: 11/30/2022] Open
Abstract
People living with HIV and who receive antiretroviral therapy have a significantly improved lifespan, compared to the early days without therapy. Unfortunately, persisting viral replication in the lungs sustains chronic inflammation, which may cause pulmonary vascular dysfunction and ultimate life-threatening Pulmonary Hypertension (PH). The mechanisms involved in the progression of HIV and PH remain unclear. The study of HIV-PH is limited due to the lack of tractable animal models that recapitulate infection and pathobiological aspects of PH. On one hand, mice with humanized immune systems (hu-mice) are highly relevant to HIV research but their suitability for HIV-PH research deserves investigation. On another hand, the Hypoxia-Sugen is a well-established model for experimental PH that combines hypoxia with the VEGF antagonist SU5416. To test the suitability of hu-mice, we combined HIV with either SU5416 or hypoxia. Using right heart catheterization, we found that combining HIV+SU5416 exacerbated PH. HIV infection increases human pro-inflammatory cytokines in the lungs, compared to uninfected mice. Histopathological examinations showed pulmonary vascular inflammation with arterial muscularization in HIV-PH. We also found an increase in endothelial-monocyte activating polypeptide II (EMAP II) when combining HIV+SU5416. Therefore, combinations of HIV with SU5416 or hypoxia recapitulate PH in hu-mice, creating well-suited models for infectious mechanistic pulmonary vascular research in small animals.
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Affiliation(s)
- Valerie J. Rodriguez-Irizarry
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States,Department of Biology, University of Puerto Rico in Ponce, Ponce, PR, United States
| | - Alina C. Schneider
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Daniel Ahle
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Justin M. Smith
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | | | - Ethan A. Salazar
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Brianyell McDaniel Mims
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Fahmida Rasha
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Hanna Moussa
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Naima Moustaïd-Moussa
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, United States
| | - Kevin Pruitt
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Marcelo Fonseca
- Program of Physiology and Biophysics, University of Chile, Santiago, Chile
| | - Mauricio Henriquez
- Program of Physiology and Biophysics, University of Chile, Santiago, Chile
| | - Matthias A. Clauss
- Pulmonary, Critical Care, Sleep and Occupational Medicine, Indiana University, Indianapolis, IN, United States
| | - Matthew B. Grisham
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Sharilyn Almodovar
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States,Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States,*Correspondence: Sharilyn Almodovar,
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3
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Productive Replication of HIV-1 but Not SIVmac in Small Ruminant Cells. Pathogens 2022; 11:pathogens11070799. [PMID: 35890043 PMCID: PMC9316499 DOI: 10.3390/pathogens11070799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 02/05/2023] Open
Abstract
Animal lentiviruses (LVs) have been proven to have the capacity to cross the species barrier, to adapt in the new hosts, and to increase their pathogenesis, therefore leading to the emergence of threatening diseases. However, their potential for widespread diffusion is limited by restrictive cellular factors that block viral replication in the cells of many species. In previous studies, we demonstrated that the restriction of CAEV infection of sheep choroid plexus cells was due to aberrant post-translation cleavage of the CAEV Env gp170 precursor. Later, we showed that the lack of specific receptor(s) for caprine encephalitis arthritis virus (CAEV) on the surface of human cells was the only barrier to their infection. Here, we examined whether small ruminant (SR) cells can support the replication of primate LVs. Three sheep and goat cell lines were inoculated with cell-free HIV-1 and SIVmac viral stocks or transfected with infectious molecular clone DNAs of these viruses. The two recombinant lentiviral clones contained the green fluorescent protein (GFP) reporter sequence. Infection was detected by GFP expression in target cells, and the infectious virus produced and released in the culture medium of treated cells was detected using the indicator TZM-bl cell line. Pseudotyped HIV-GFP and SIV-GFP with vesicular stomatitis virus G glycoprotein (VSV-G) allowed the cell receptors to be overcome for virus entry to further evaluate the viral replication/restriction in SR cells. As expected, neither HIV nor SIV viruses infected any of the SR cells. In contrast, the transfection of plasmid DNAs of the infectious molecular clones of both viruses in SR cells produced high titers of infectious viruses for human indicators, but not SR cell lines. Surprisingly, SR cells inoculated with HIV-GFP/VSV-G, but not SIV-GFP/VSV-G, expressed the GFP and produced a virus that efficiently infected the human indictor, but not the SR cells. Collectively, these data provide a demonstration of the lack of replication of the SIVmac genome in SR cells, while, in contrast, there was no restriction on the replication of the IV-1 genome in these cells. However, because of the lack of functional receptors to SIVmac and HIV-1 at the surface of SR cells, there is specific lentiviral entry.
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4
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Kumar A, Mahajan A, Salazar EA, Pruitt K, Guzman CA, Clauss MA, Almodovar S, Dhillon NK. Impact of human immunodeficiency virus on pulmonary vascular disease. Glob Cardiol Sci Pract 2021; 2021:e202112. [PMID: 34285903 PMCID: PMC8272407 DOI: 10.21542/gcsp.2021.12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 05/31/2021] [Indexed: 01/08/2023] Open
Abstract
With the advent of anti-retroviral therapy, non-AIDS-related comorbidities have increased in people living with HIV. Among these comorbidities, pulmonary hypertension (PH) is one of the most common causes of morbidity and mortality. Although chronic HIV-1 infection is independently associated with the development of pulmonary arterial hypertension, PH in people living with HIV may also be the outcome of various co-morbidities commonly observed in these individuals including chronic obstructive pulmonary disease, left heart disease and co-infections. In addition, the association of these co-morbidities and other risk factors, such as illicit drug use, can exacerbate the development of pulmonary vascular disease. This review will focus on these complex interactions contributing to PH development and exacerbation in HIV patients. We also examine the interactions of HIV proteins, including Nef, Tat, and gp120 in the pulmonary vasculature and how these proteins alter the endothelial and smooth muscle function by transforming them into susceptible PH phenotype. The review also discusses the available infectious and non-infectious animal models to study HIV-associated PAH, highlighting the advantages and disadvantages of each model, along with their ability to mimic the clinical manifestations of HIV-PAH.
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Affiliation(s)
- Ashok Kumar
- Pulmonary, Critical Care and Sleep Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Aatish Mahajan
- Pulmonary, Critical Care and Sleep Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Ethan A Salazar
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Kevin Pruitt
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Christian Arce Guzman
- Pulmonary, Critical Care, Sleep & Occupational Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Matthias A Clauss
- Pulmonary, Critical Care, Sleep & Occupational Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sharilyn Almodovar
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Navneet K Dhillon
- Pulmonary, Critical Care and Sleep Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
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5
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The Role of APOBECs in Viral Replication. Microorganisms 2020; 8:microorganisms8121899. [PMID: 33266042 PMCID: PMC7760323 DOI: 10.3390/microorganisms8121899] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/14/2022] Open
Abstract
Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC) proteins are a diverse and evolutionarily conserved family of cytidine deaminases that provide a variety of functions from tissue-specific gene expression and immunoglobulin diversity to control of viruses and retrotransposons. APOBEC family expansion has been documented among mammalian species, suggesting a powerful selection for their activity. Enzymes with a duplicated zinc-binding domain often have catalytically active and inactive domains, yet both have antiviral function. Although APOBEC antiviral function was discovered through hypermutation of HIV-1 genomes lacking an active Vif protein, much evidence indicates that APOBECs also inhibit virus replication through mechanisms other than mutagenesis. Multiple steps of the viral replication cycle may be affected, although nucleic acid replication is a primary target. Packaging of APOBECs into virions was first noted with HIV-1, yet is not a prerequisite for viral inhibition. APOBEC antagonism may occur in viral producer and recipient cells. Signatures of APOBEC activity include G-to-A and C-to-T mutations in a particular sequence context. The importance of APOBEC activity for viral inhibition is reflected in the identification of numerous viral factors, including HIV-1 Vif, which are dedicated to antagonism of these deaminases. Such viral antagonists often are only partially successful, leading to APOBEC selection for viral variants that enhance replication or avoid immune elimination.
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6
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Impact of Suboptimal APOBEC3G Neutralization on the Emergence of HIV Drug Resistance in Humanized Mice. J Virol 2020; 94:JVI.01543-19. [PMID: 31801862 DOI: 10.1128/jvi.01543-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/20/2019] [Indexed: 01/05/2023] Open
Abstract
HIV diversification facilitates immune escape and complicates antiretroviral therapy. In this study, we take advantage of a humanized-mouse model to probe the contribution of APOBEC3 mutagenesis to viral evolution. Humanized mice were infected with isogenic HIV molecular clones (HIV-WT, HIV-45G, and HIV-ΔSLQ) that differ in their abilities to counteract APOBEC3G (A3G). Infected mice remained naive or were treated with the reverse transcriptase (RT) inhibitor lamivudine (3TC). Viremia, emergence of drug-resistant variants, and quasispecies diversification in the plasma compartment were determined throughout infection. While both HIV-WT and HIV-45G achieved robust infection, over time, HIV-45G replication was significantly reduced compared to that of HIV-WT in the absence of 3TC treatment. In contrast, treatment responses differed significantly between HIV-45G- and HIV-WT-infected mice. Antiretroviral treatment failed in 91% of HIV-45G-infected mice, while only 36% of HIV-WT-infected mice displayed a similar negative outcome. Emergence of 3TC-resistant variants and nucleotide diversity were determined by analyzing 155,462 single HIV reverse transcriptase gene (RT) and 6,985 vif sequences from 33 mice. Prior to treatment, variants with genotypic 3TC resistance (RT-M184I/V) were detected at low levels in over a third of all the animals. Upon treatment, the composition of the plasma quasispecies rapidly changed, leading to a majority of circulating viral variants encoding RT-184I. Interestingly, increased viral diversity prior to treatment initiation correlated with higher plasma viremia in HIV-45G-infected animals, but not in HIV-WT-infected animals. Taken together, HIV variants with suboptimal anti-A3G activity were attenuated in the absence of selection but displayed a fitness advantage in the presence of antiretroviral treatment.IMPORTANCE Both viral (e.g., RT) and host (e.g., A3G) factors can contribute to HIV sequence diversity. This study shows that suboptimal anti-A3G activity shapes viral fitness and drives viral evolution in the plasma compartment in humanized mice.
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7
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Nixon CC, Mavigner M, Sampey GC, Brooks AD, Spagnuolo RA, Irlbeck DM, Mattingly C, Ho PT, Schoof N, Cammon CG, Tharp GK, Kanke M, Wang Z, Cleary RA, Upadhyay AA, De C, Wills SR, Falcinelli SD, Galardi C, Walum H, Schramm NJ, Deutsch J, Lifson JD, Fennessey CM, Keele BF, Jean S, Maguire S, Liao B, Browne EP, Ferris RG, Brehm JH, Favre D, Vanderford TH, Bosinger SE, Jones CD, Routy JP, Archin NM, Margolis DM, Wahl A, Dunham RM, Silvestri G, Chahroudi A, Garcia JV. Systemic HIV and SIV latency reversal via non-canonical NF-κB signalling in vivo. Nature 2020; 578:160-165. [PMID: 31969707 PMCID: PMC7111210 DOI: 10.1038/s41586-020-1951-3] [Citation(s) in RCA: 198] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 12/16/2019] [Indexed: 01/27/2023]
Abstract
Long-lasting, latently infected resting CD4+ T cells are the greatest obstacle to obtaining a cure for HIV infection, as these cells can persist despite decades of treatment with antiretroviral therapy (ART). Estimates indicate that more than 70 years of continuous, fully suppressive ART are needed to eliminate the HIV reservoir1. Alternatively, induction of HIV from its latent state could accelerate the decrease in the reservoir, thus reducing the time to eradication. Previous attempts to reactivate latent HIV in preclinical animal models and in clinical trials have measured HIV induction in the peripheral blood with minimal focus on tissue reservoirs and have had limited effect2-9. Here we show that activation of the non-canonical NF-κB signalling pathway by AZD5582 results in the induction of HIV and SIV RNA expression in the blood and tissues of ART-suppressed bone-marrow-liver-thymus (BLT) humanized mice and rhesus macaques infected with HIV and SIV, respectively. Analysis of resting CD4+ T cells from tissues after AZD5582 treatment revealed increased SIV RNA expression in the lymph nodes of macaques and robust induction of HIV in almost all tissues analysed in humanized mice, including the lymph nodes, thymus, bone marrow, liver and lung. This promising approach to latency reversal-in combination with appropriate tools for systemic clearance of persistent HIV infection-greatly increases opportunities for HIV eradication.
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Affiliation(s)
- Christopher C Nixon
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Maud Mavigner
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Gavin C Sampey
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Qura Therapeutics, Chapel Hill, NC, USA
| | - Alyssa D Brooks
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Rae Ann Spagnuolo
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David M Irlbeck
- Qura Therapeutics, Chapel Hill, NC, USA
- HIV Drug Discovery, ViiV Healthcare, Research Triangle Park, NC, USA
| | - Cameron Mattingly
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Phong T Ho
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nils Schoof
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Corinne G Cammon
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Greg K Tharp
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Matthew Kanke
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhang Wang
- GlaxoSmithKline Research and Development, Collegeville, PA, USA
| | - Rachel A Cleary
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amit A Upadhyay
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Chandrav De
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Saintedym R Wills
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Qura Therapeutics, Chapel Hill, NC, USA
| | - Shane D Falcinelli
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Cristin Galardi
- Qura Therapeutics, Chapel Hill, NC, USA
- HIV Drug Discovery, ViiV Healthcare, Research Triangle Park, NC, USA
| | - Hasse Walum
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Nathaniel J Schramm
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Christine M Fennessey
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Sherrie Jean
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Sean Maguire
- GlaxoSmithKline Research and Development, Collegeville, PA, USA
| | - Baolin Liao
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Infectious Diseases, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Edward P Browne
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Robert G Ferris
- Qura Therapeutics, Chapel Hill, NC, USA
- HIV Drug Discovery, ViiV Healthcare, Research Triangle Park, NC, USA
| | - Jessica H Brehm
- Qura Therapeutics, Chapel Hill, NC, USA
- HIV Drug Discovery, ViiV Healthcare, Research Triangle Park, NC, USA
| | - David Favre
- Qura Therapeutics, Chapel Hill, NC, USA
- GlaxoSmithKline Research and Development, Collegeville, PA, USA
| | | | - Steven E Bosinger
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Corbin D Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jean-Pierre Routy
- Chronic Viral Infection Service, McGill University Health Centre, Montreal, Quebec, Canada
- Division of Hematology, McGill University Health Centre, Montreal, Quebec, Canada
| | - Nancie M Archin
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David M Margolis
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Qura Therapeutics, Chapel Hill, NC, USA
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Epidemiology, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Angela Wahl
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Richard M Dunham
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- UNC HIV Cure Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Qura Therapeutics, Chapel Hill, NC, USA.
- HIV Drug Discovery, ViiV Healthcare, Research Triangle Park, NC, USA.
| | - Guido Silvestri
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Ann Chahroudi
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.
- Emory + Children's Center for Childhood Infections and Vaccines, Atlanta, GA, USA.
| | - J Victor Garcia
- International Center for the Advancement of Translational Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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8
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Role of co-expressed APOBEC3F and APOBEC3G in inducing HIV-1 drug resistance. Heliyon 2019; 5:e01498. [PMID: 31025011 PMCID: PMC6475876 DOI: 10.1016/j.heliyon.2019.e01498] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/24/2019] [Accepted: 04/05/2019] [Indexed: 01/04/2023] Open
Abstract
The APOBEC3 enzymes can induce mutagenesis of HIV-1 proviral DNA through the deamination of cytosine. HIV-1 overcomes this restriction through the viral protein Vif that induces APOBEC3 proteasomal degradation. Within this dynamic host-pathogen relationship, the APOBEC3 enzymes have been found to be beneficial, neutral, or detrimental to HIV-1 biology. Here, we assessed the ability of co-expressed APOBEC3F and APOBEC3G to induce HIV-1 resistance to antiviral drugs. We found that co-expression of APOBEC3F and APOBEC3G enabled partial resistance of APOBEC3F to Vif-mediated degradation with a corresponding increase in APOBEC3F-induced deaminations in the presence of Vif, in addition to APOBEC3G-induced deaminations. We recovered HIV-1 drug resistant variants resulting from APOBEC3-induced mutagenesis, but these variants were less able to replicate than drug resistant viruses derived from RT-induced mutations alone. The data support a model in which APOBEC3 enzymes cooperate to restrict HIV-1, promoting viral inactivation over evolution to drug resistance.
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9
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Salter JD, Polevoda B, Bennett RP, Smith HC. Regulation of Antiviral Innate Immunity Through APOBEC Ribonucleoprotein Complexes. Subcell Biochem 2019; 93:193-219. [PMID: 31939152 DOI: 10.1007/978-3-030-28151-9_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The DNA mutagenic enzyme known as APOBEC3G (A3G) plays a critical role in innate immunity to Human Immunodeficiency Virus-1 (HIV-1 ). A3G is a zinc-dependent enzyme that mutates select deoxycytidines (dC) to deoxyuridine (dU) through deamination within nascent single stranded DNA (ssDNA) during HIV reverse transcription. This activity requires that the enzyme be delivered to viral replication complexes by redistributing from the cytoplasm of infected cells to budding virions through what appears to be an RNA-dependent process. Once inside infected cells, A3G must bind to nascent ssDNA reverse transcripts for dC to dU base modification gene editing. In this chapter we will discuss data indicating that ssDNA deaminase activity of A3G is regulated by RNA binding to A3G and ribonucleoprotein complex formation along with evidence suggesting that RNA-selective interactions with A3G are temporally and mechanistically important in this process.
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Affiliation(s)
- Jason D Salter
- OyaGen, Inc, 77 Ridgeland Road, Rochester, NY, 14623, USA
| | - Bogdan Polevoda
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Rochester, NY, 14642, USA
| | - Ryan P Bennett
- OyaGen, Inc, 77 Ridgeland Road, Rochester, NY, 14623, USA
| | - Harold C Smith
- OyaGen, Inc, 77 Ridgeland Road, Rochester, NY, 14623, USA. .,Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Rochester, NY, 14642, USA.
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10
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Anderson BD, Ikeda T, Moghadasi SA, Martin AS, Brown WL, Harris RS. Natural APOBEC3C variants can elicit differential HIV-1 restriction activity. Retrovirology 2018; 15:78. [PMID: 30558640 PMCID: PMC6297987 DOI: 10.1186/s12977-018-0459-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 12/06/2018] [Indexed: 01/29/2023] Open
Abstract
Background The APOBEC3 (A3) family of DNA cytosine deaminases provides an innate barrier to infection by retroviruses including HIV-1. A total of five enzymes, A3C, A3D, A3F, A3G and A3H, are degraded by the viral accessory protein Vif and expressed at high levels in CD4+ T cells, the primary reservoir for HIV-1 replication in vivo. Apart from A3C, all of these enzymes mediate restriction of Vif-deficient HIV-1. However, a rare variant of human A3C (Ile188) was shown recently to restrict Vif-deficient HIV-1 in a 293T-based single cycle infection system. The potential activity of this naturally occurring A3C variant has yet to be characterized in a T cell-based spreading infection system. Here we employ a combination of Cas9/gRNA disruption and transient and stable protein expression to assess the roles of major Ser188 and minor Ile188 A3C variants in HIV-1 restriction in T cell lines. Results Cas9-mediated mutation of endogenous A3C in the non-permissive CEM2n T cell line did not alter HIV-1 replication kinetics, and complementation with A3C-Ser188 or A3C-Ile188 was similarly aphenotypic. Stable expression of A3C-Ser188 in the permissive T cell line SupT11 also had little effect. However, stable expression of A3C-Ile188 in SupT11 cells inhibited Vif-deficient virus replication and inflicted G-to-A mutations. Conclusions A3C-Ile188 is capable of inhibiting Vif-deficient HIV-1 replication in T cells. Although A3C is eclipsed by the dominant anti-viral activities of other A3s in non-permissive T cell lines and primary T lymphocytes, this enzyme may still be able to contribute to HIV-1 diversification in vivo. Our results highlight the functional redundancy in the human A3 family with regards to HIV-1 restriction and the need to consider naturally occurring variants.
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Affiliation(s)
- Brett D Anderson
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Terumasa Ikeda
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Howard Hughes Medical Institute, University of Minnesota, 2231 6th St. S.E., Minneapolis, MN, 55455, USA
| | - Seyed Arad Moghadasi
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Amber St Martin
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - William L Brown
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA. .,Howard Hughes Medical Institute, University of Minnesota, 2231 6th St. S.E., Minneapolis, MN, 55455, USA.
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11
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Hossain D, Ferreira Barbosa JA, Cohen ÉA, Tsang WY. HIV-1 Vpr hijacks EDD-DYRK2-DDB1 DCAF1 to disrupt centrosome homeostasis. J Biol Chem 2018; 293:9448-9460. [PMID: 29724823 PMCID: PMC6005440 DOI: 10.1074/jbc.ra117.001444] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 04/17/2018] [Indexed: 11/06/2022] Open
Abstract
Viruses exploit the host cell machinery for their own profit. To evade innate immune sensing and promote viral replication, HIV type 1 (HIV-1) subverts DNA repair regulatory proteins and induces G2/M arrest. The preintegration complex of HIV-1 is known to traffic along microtubules and accumulate near the microtubule-organizing center. The centrosome is the major microtubule-organizing center in most eukaryotic cells, but precisely how HIV-1 impinges on centrosome biology remains poorly understood. We report here that the HIV-1 accessory protein viral protein R (Vpr) localized to the centrosome through binding to DCAF1, forming a complex with the ubiquitin ligase EDD-DYRK2-DDB1DCAF1 and Cep78, a resident centrosomal protein previously shown to inhibit EDD-DYRK2-DDB1DCAF1 Vpr did not affect ubiquitination of Cep78. Rather, it enhanced ubiquitination of an EDD-DYRK2-DDB1DCAF1 substrate, CP110, leading to its degradation, an effect that could be overcome by Cep78 expression. The down-regulation of CP110 and elongation of centrioles provoked by Vpr were independent of G2/M arrest. Infection of T lymphocytes with HIV-1, but not with HIV-1 lacking Vpr, promoted CP110 degradation and centriole elongation. Elongated centrioles recruited more γ-tubulin to the centrosome, resulting in increased microtubule nucleation. Our results suggest that Vpr is targeted to the centrosome where it hijacks a ubiquitin ligase, disrupting organelle homeostasis, which may contribute to HIV-1 pathogenesis.
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Affiliation(s)
- Delowar Hossain
- From the Institut de recherches cliniques de Montréal, Montreal, Quebec H2W 1R7, Canada
- the Division of Experimental Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | | | - Éric A Cohen
- From the Institut de recherches cliniques de Montréal, Montreal, Quebec H2W 1R7, Canada
- the Division of Experimental Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
- the Department of Microbiology, Infectiology, and Immunology, Université de Montréal, Montreal, Quebec H3C 3J7, Canada, and
| | - William Y Tsang
- From the Institut de recherches cliniques de Montréal, Montreal, Quebec H2W 1R7, Canada,
- the Division of Experimental Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
- the Department of Pathology and Cell Biology, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
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12
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Bennett RP, Salter JD, Smith HC. A New Class of Antiretroviral Enabling Innate Immunity by Protecting APOBEC3 from HIV Vif-Dependent Degradation. Trends Mol Med 2018; 24:507-520. [PMID: 29609878 PMCID: PMC7362305 DOI: 10.1016/j.molmed.2018.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/05/2018] [Accepted: 03/08/2018] [Indexed: 12/11/2022]
Abstract
The infectivity of HIV depends on overcoming APOBEC3 (A3) innate immunity, predominantly through the expression of the viral protein Vif, which induces A3 degradation in the proteasome. Disruption of the functional interactions of Vif enables A3 mutagenesis of the HIV genome during viral replication, which can result in a broadly neutralizing antiviral effect. Vif function requires self-association along with interactions with A3 proteins, protein chaperones, and factors of the ubiquitination machinery and these are described here as a potential platform for novel antiviral drug discovery. This Review will examine the current state of development of Vif inhibitors that we believe to have therapeutic and functional cure potential.
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Affiliation(s)
- Ryan P Bennett
- OyaGen, Inc., 77 Ridgeland Road, Rochester, NY 14623, USA.
| | - Jason D Salter
- OyaGen, Inc., 77 Ridgeland Road, Rochester, NY 14623, USA
| | - Harold C Smith
- OyaGen, Inc., 77 Ridgeland Road, Rochester, NY 14623, USA; University of Rochester, School of Medicine and Dentistry, Department of Biochemistry and Biophysics, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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T cells with low CD2 levels express reduced restriction factors and are preferentially infected in therapy naïve chronic HIV-1 patients. J Int AIDS Soc 2018; 20:21865. [PMID: 28953327 PMCID: PMC5964667 DOI: 10.7448/ias.20.1.21865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Restriction factors (RFs) suppress HIV-1 in cell lines and primary cell models. Hence, RFs might be attractive targets for novel antiviral strategies, but their importance for virus control in vivo is controversial. METHODS We profiled the expression of RFs in primary blood-derived mononuclear cells (PBMC) from therapy-naïve HIV-1 patients and quantified infection. RESULTS Overall, there was no correlation between individual RF expression and HIV-1 status in total PBMC. However, we identified a T cell population with low levels of intracellular CD2 and reduced expression of SAMHD1, p21 and SerinC5. CD2low T cells with reduced RF expression were markedly positive for HIV-1 p24. In contrast, CD2+ T cells were less infected and expressed higher levels of RFs. CD2low T cell infection correlated with viral loads and was associated with HIV-1 disease progression. CONCLUSIONS In untreated therapy naïve chronic HIV-1 patients, RF expression in T cells is associated with CD2 expression and seems to influence viral loads. Our study suggests that RFs help to control HIV-1 infection in certain T cells in vivo and supports the potential for RFs as promising targets for therapeutic intervention.
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14
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Honeycutt JB, Garcia JV. Humanized mice: models for evaluating NeuroHIV and cure strategies. J Neurovirol 2017; 24:185-191. [PMID: 28831774 DOI: 10.1007/s13365-017-0567-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/29/2017] [Accepted: 08/08/2017] [Indexed: 02/06/2023]
Abstract
While the human immunodeficiency virus (HIV) epidemic was initially characterized by a high prevalence of severe and widespread neurological pathologies, the development of better treatments to suppress viremia over years and even decades has mitigated many of the severe neurological pathologies previously observed. Despite effective treatment, mild neurocognitive impairment and premature cognitive aging are observed in HIV-infected individuals, suggesting a changing but ongoing role of HIV infection in the central nervous system (CNS). Although current therapies are effective in suppressing viremia, they are not curative and patients must remain on life-long treatment or risk recrudescence of virus. Important for the development and evaluation of a cure for HIV will be animal models that recapitulate critical aspects of infection in vivo. In the following, we seek to summarize some of the recent developments in humanized mouse models and their usefulness in modeling HIV infection of the CNS and HIV cure strategies.
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Affiliation(s)
- Jenna B Honeycutt
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina (UNC), School of Medicine, Chapel Hill, NC, USA.
| | - J Victor Garcia
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina (UNC), School of Medicine, Chapel Hill, NC, USA
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15
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Nakano Y, Aso H, Soper A, Yamada E, Moriwaki M, Juarez-Fernandez G, Koyanagi Y, Sato K. A conflict of interest: the evolutionary arms race between mammalian APOBEC3 and lentiviral Vif. Retrovirology 2017; 14:31. [PMID: 28482907 PMCID: PMC5422959 DOI: 10.1186/s12977-017-0355-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/27/2017] [Indexed: 01/06/2023] Open
Abstract
Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) proteins are mammalian-specific cellular deaminases and have a robust ability to restrain lentivirus replication. To antagonize APOBEC3-mediated antiviral action, lentiviruses have acquired viral infectivity factor (Vif) as an accessory gene. Mammalian APOBEC3 proteins inhibit lentiviral replication by enzymatically inserting G-to-A hypermutations in the viral genome, whereas lentiviral Vif proteins degrade host APOBEC3 via the ubiquitin/proteasome-dependent pathway. Recent investigations provide evidence that lentiviral vif genes evolved to combat mammalian APOBEC3 proteins. In corollary, mammalian APOBEC3 genes are under Darwinian selective pressure to escape from antagonism by Vif. Based on these observations, it is widely accepted that lentiviral Vif and mammalian APOBEC3 have co-evolved and this concept is called an "evolutionary arms race." This review provides a comprehensive summary of current knowledge with respect to the evolutionary dynamics occurring at this pivotal host-virus interface.
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Affiliation(s)
- Yusuke Nakano
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
| | - Hirofumi Aso
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
- Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Andrew Soper
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
| | - Eri Yamada
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
| | - Miyu Moriwaki
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Guillermo Juarez-Fernandez
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
| | - Yoshio Koyanagi
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
| | - Kei Sato
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoinkawara-cho, Sakyo-ku, Kyoto, 6068507 Japan
- CREST, Japan Science and Technology Agency, Saitama, Japan
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16
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Ito F, Fu Y, Kao SCA, Yang H, Chen XS. Family-Wide Comparative Analysis of Cytidine and Methylcytidine Deamination by Eleven Human APOBEC Proteins. J Mol Biol 2017; 429:1787-1799. [PMID: 28479091 DOI: 10.1016/j.jmb.2017.04.021] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 04/28/2017] [Accepted: 04/29/2017] [Indexed: 01/17/2023]
Abstract
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) proteins are a family of cytidine deaminases involved in various important biological processes such as antibody diversification/maturation, restriction of viral infection, and generation of somatic mutations. Catalytically active APOBEC proteins execute their biological functions mostly through deaminating cytosine (C) to uracil on single-stranded DNA/RNA. Activation-induced cytidine deaminase, one of the APOBEC members, was reported to deaminate methylated cytosine (mC) on DNA, and this mC deamination was proposed to be involved in the demethylation of mC for epigenetic regulation. The mC deamination activity is later demonstrated for APOBEC3A (A3A) and more recently for APOBEC3B and APOBEC3H (A3H). Despite extensive studies on APOBEC proteins, questions regarding whether the rest of APOBEC members have any mC deaminase activity and what are the relative deaminase activities for each APOBEC member remain unclear. Here, we performed a family-wide analysis of deaminase activities on C and mC by using purified recombinant proteins for 11 known human APOBEC proteins under similar conditions. Our comprehensive analyses revealed that each APOBEC has unique deaminase activity and selectivity for mC. A3A and A3H showed distinctively high deaminase activities on C and mC with relatively high selectivity for mC, whereas six other APOBEC members showed relatively low deaminase activity and selectivity for mC. Our mutational analysis showed that loop-1 of A3A is responsible for its high deaminase activity and selectivity for mC. These findings extend our understanding of APOBEC family proteins that have important roles in diverse biological functions and in genetic mutations.
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Affiliation(s)
- Fumiaki Ito
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Yang Fu
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Shen-Chi A Kao
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Hanjing Yang
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA; Department of Chemistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA; Center of Excellence in NanoBiophysics, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA.
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17
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Nakano Y, Misawa N, Juarez-Fernandez G, Moriwaki M, Nakaoka S, Funo T, Yamada E, Soper A, Yoshikawa R, Ebrahimi D, Tachiki Y, Iwami S, Harris RS, Koyanagi Y, Sato K. HIV-1 competition experiments in humanized mice show that APOBEC3H imposes selective pressure and promotes virus adaptation. PLoS Pathog 2017; 13:e1006348. [PMID: 28475648 PMCID: PMC5435363 DOI: 10.1371/journal.ppat.1006348] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/17/2017] [Accepted: 04/12/2017] [Indexed: 01/14/2023] Open
Abstract
APOBEC3 (A3) family proteins are DNA cytosine deaminases recognized for contributing to HIV-1 restriction and mutation. Prior studies have demonstrated that A3D, A3F, and A3G enzymes elicit a robust anti-HIV-1 effect in cell cultures and in humanized mouse models. Human A3H is polymorphic and can be categorized into three phenotypes: stable, intermediate, and unstable. However, the anti-viral effect of endogenous A3H in vivo has yet to be examined. Here we utilize a hematopoietic stem cell-transplanted humanized mouse model and demonstrate that stable A3H robustly affects HIV-1 fitness in vivo. In contrast, the selection pressure mediated by intermediate A3H is relaxed. Intriguingly, viral genomic RNA sequencing reveled that HIV-1 frequently adapts to better counteract stable A3H during replication in humanized mice. Molecular phylogenetic analyses and mathematical modeling suggest that stable A3H may be a critical factor in human-to-human viral transmission. Taken together, this study provides evidence that stable variants of A3H impose selective pressure on HIV-1.
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Affiliation(s)
- Yusuke Nakano
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Naoko Misawa
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Guillermo Juarez-Fernandez
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Miyu Moriwaki
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Shinji Nakaoka
- Institute of Industrial Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Takaaki Funo
- Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Eri Yamada
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Andrew Soper
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Rokusuke Yoshikawa
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Diako Ebrahimi
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Yuuya Tachiki
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Shingo Iwami
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Yoshio Koyanagi
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Kei Sato
- Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
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18
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Okada A, Iwatani Y. APOBEC3G-Mediated G-to-A Hypermutation of the HIV-1 Genome: The Missing Link in Antiviral Molecular Mechanisms. Front Microbiol 2016; 7:2027. [PMID: 28066353 PMCID: PMC5165236 DOI: 10.3389/fmicb.2016.02027] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/02/2016] [Indexed: 12/20/2022] Open
Abstract
APOBEC3G (A3G) is a member of the cellular polynucleotide cytidine deaminases, which catalyze the deamination of cytosine (dC) to uracil (dU) in single-stranded DNA. These enzymes potently inhibit the replication of a variety of retroviruses and retrotransposons, including HIV-1. A3G is incorporated into vif-deficient HIV-1 virions and targets viral reverse transcripts, particularly minus-stranded DNA products, in newly infected cells. It is well established that the enzymatic activity of A3G is closely correlated with the potential to greatly inhibit HIV-1 replication in the absence of Vif. However, the details of the underlying molecular mechanisms are not fully understood. One potential mechanism of A3G antiviral activity is that the A3G-dependent deamination may trigger degradation of the dU-containing reverse transcripts by cellular uracil DNA glycosylases (UDGs). More recently, another mechanism has been suggested, in which the virion-incorporated A3G generates lethal levels of the G-to-A hypermutation in the viral DNA genome, thus potentially driving the viruses into “error catastrophe” mode. In this mini review article, we summarize the deaminase-dependent and deaminase-independent molecular mechanisms of A3G and discuss how A3G-mediated deamination is linked to antiviral mechanisms.
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Affiliation(s)
- Ayaka Okada
- Department of Microbiology and Immunology, Laboratory of Infectious Diseases, Clinical Research Center, National Hospital Organization Nagoya Medical Center Nagoya, Japan
| | - Yasumasa Iwatani
- Department of Microbiology and Immunology, Laboratory of Infectious Diseases, Clinical Research Center, National Hospital Organization Nagoya Medical CenterNagoya, Japan; Department of AIDS Research, Nagoya University Graduate School of MedicineNagoya, Japan
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Li SX, Barrett BS, Guo K, Santiago ML. Tetherin/BST-2: Restriction Factor or Immunomodulator? Curr HIV Res 2016; 14:235-46. [PMID: 26957198 DOI: 10.2174/1570162x14999160224102752] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cell-mediated immune (CMI) responses are critical for the control of HIV-1 infection and their importance was highlighted by the existence of viral proteins, particularly Vpu and Nef, that antagonize these responses. Pandemic HIV-1 Vpu counteracts Tetherin/BST-2, a host factor that could prevent the release of HIV-1 virions by tethering virions on the cell surface, but a link between Tetherin and HIV-1 CMI responses has not yet been demonstrated in vivo. In vitro, the virological and immunological impact of Tetherin-mediated accumulation of virions ranged from enhanced or diminished cell-to-cell spread to enhanced recognition by virus-specific antibodies for natural killer cellmediated lysis. However, Tetherin-restricted virions could be internalized through an endocytosis motif in the Tetherin cytoplasmic tail. METHODS Given the uncertainties on which in vitro results manifest in vivo and the dearth of knowledge on how Tetherin influences retroviral immunity, in vivo retrovirus infections in mice encoding wild-type, null and endocytosis-defective Tetherin were performed. Here, we review and highlight the results from these in vivo studies. RESULTS Current data suggests that endocytosis-defective Tetherin functions as a potent innate restriction factor. By contrast, endocytosis-competent Tetherin, the form found in most mammals including humans and the form counteracted by HIV-1 Vpu, was linked to stronger CMI responses in mice. CONCLUSION We propose that the main role of endocytosis-competent Tetherin is not to directly restrict retroviral replication, but to promote a more effective CMI response against retroviruses.
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Affiliation(s)
| | | | | | - Mario L Santiago
- Division of Infectious Diseases, University of Colorado Denver, Mail Stop B-168, 12700 E 19th Avenue, Aurora, CO 80045, USA.
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HIV Maintains an Evolving and Dispersed Population in Multiple Tissues during Suppressive Combined Antiretroviral Therapy in Individuals with Cancer. J Virol 2016; 90:8984-93. [PMID: 27466425 DOI: 10.1128/jvi.00684-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/13/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED While combined antiretroviral therapy (cART) can result in undetectable plasma viral loads, it does not eradicate HIV infection. Furthermore, HIV-infected individuals while on cART remain at an increased risk of developing serious comorbidities, such as cancer, neurological disease, and atherosclerosis, suggesting that during cART, tissue-based HIV may contribute to such pathologies. We obtained DNA and RNA env, nef, and pol sequences using single-genome sequencing from postmortem tissues of three HIV(+) cART-treated (cART(+)) individuals with undetectable viral load and metastatic cancer at death and performed time-scaled Bayesian evolutionary analyses. We used a sensitive in situ hybridization technique to visualize HIV gag-pol mRNA transcripts in cerebellum and lymph node tissues from one patient. Tissue-associated virus evolved at similar rates in cART(+) and cART-naive (cART(-)) patients. Phylogenetic trees were characterized by two distinct features: (i) branching patterns consistent with constant viral evolution and dispersal among tissues and (ii) very recently derived clades containing both DNA and RNA sequences from multiple tissues. Rapid expansion of virus near death corresponded to wide-spread metastasis. HIV RNA(+) cells clustered in cerebellum tissue but were dispersed in lymph node tissue, mirroring the evolutionary patterns observed for that patient. Activated, infiltrating macrophages were associated with HIV RNA. Our data provide evidence that tissues serve as a sanctuary for wild-type HIV during cART and suggest the importance of macrophages as an alternative reservoir and mechanism of virus spread. IMPORTANCE Combined antiretroviral therapy (cART) reduces plasma HIV to undetectable levels; however, removal of cART results in plasma HIV rebound, thus highlighting its inability to entirely rid the body of infection. Additionally, HIV-infected individuals on cART remain at high risk of serious diseases, which suggests a contribution from residual HIV. In this study, we isolated and sequenced HIV from postmortem tissues from three HIV(+) cART(+) individuals who died with metastatic cancer and had no detectable plasma viral load. Using high-resolution evolutionary analyses, we found that tissue-based HIV continues to replicate, evolve, and migrate among tissues during cART. Furthermore, cancer onset and metastasis coincided with increased HIV expansion, suggesting a linked mechanism. HIV-expressing cells were associated with tissue macrophages, a target of HIV infection. Our results suggest the importance of tissues, and macrophages in particular, as a target for novel anti-HIV therapies.
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21
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Ernst W. Humanized mice in infectious diseases. Comp Immunol Microbiol Infect Dis 2016; 49:29-38. [PMID: 27865261 DOI: 10.1016/j.cimid.2016.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 08/12/2016] [Accepted: 08/12/2016] [Indexed: 02/06/2023]
Abstract
The pathogenesis of infectious agents with human tropism can only be properly studied in an in vivo model featuring human cells or tissue. Humanized mice represent a small animal model featuring human cells or tissue that can be infected by human-specific viruses, bacteria, and parasites and also providing a functional human immune system. This makes the analysis of a human immune response to infection possible and allows for preclinical testing of new vaccines and therapeutic agents. Results of various studies using humanized mice to investigate pathogens with human tropism are presented in this review. In addition, the limitations of humanized mice and methods to improve this valuable animal model are discussed.
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Affiliation(s)
- W Ernst
- Clinic of Gynecology and Obstetrics St. Hedwig, University of Regensburg, Regensburg, Bavaria, Germany.
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22
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Shanmugasundaram U, Kovarova M, Ho PT, Schramm N, Wahl A, Parniak MA, Garcia JV. Efficient Inhibition of HIV Replication in the Gastrointestinal and Female Reproductive Tracts of Humanized BLT Mice by EFdA. PLoS One 2016; 11:e0159517. [PMID: 27438728 PMCID: PMC4954669 DOI: 10.1371/journal.pone.0159517] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/05/2016] [Indexed: 02/07/2023] Open
Abstract
Background The nucleoside reverse transcriptase inhibitor (NRTI) 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) in preclinical development exhibits improved safety and antiviral activity profiles with minimal drug resistance compared to approved NRTIs. However, the systemic antiviral efficacy of EFdA has not been fully evaluated. In this study, we utilized bone marrow/liver/thymus (BLT) humanized mice to investigate the systemic effect of EFdA treatment on HIV replication and CD4+ T cell depletion in the peripheral blood (PB) and tissues. In particular, we performed a comprehensive analysis of the female reproductive tract (FRT) and gastrointestinal (GI) tract, major sites of transmission, viral replication, and CD4+ T cell depletion and where some current antiretroviral drugs have a sub-optimal effect. Results EFdA treatment resulted in reduction of HIV-RNA in PB to undetectable levels in the majority of treated mice by 3 weeks post-treatment. HIV-RNA levels in cervicovaginal lavage of EFdA-treated BLT mice also declined to undetectable levels demonstrating strong penetration of EFdA into the FRT. Our results also demonstrate a strong systemic suppression of HIV replication in all tissues analyzed. In particular, we observed more than a 2-log difference in HIV-RNA levels in the GI tract and FRT of EFdA-treated BLT mice compared to untreated HIV-infected control mice. In addition, HIV-RNA was also significantly lower in the lymph nodes, liver, lung, spleen of EFdA-treated BLT mice compared to untreated HIV-infected control mice. Furthermore, EFdA treatment prevented the depletion of CD4+ T cells in the PB, mucosal tissues and lymphoid tissues. Conclusion Our findings indicate that EFdA is highly effective in controlling viral replication and preserving CD4+ T cells in particular with high efficiency in the GI and FRT tract. Thus, EFdA represents a strong potential candidate for further development as a part of antiretroviral therapy regimens.
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Affiliation(s)
- Uma Shanmugasundaram
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Martina Kovarova
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Phong T. Ho
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Nathaniel Schramm
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Angela Wahl
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Michael A. Parniak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - J. Victor Garcia
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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23
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Cadena C, Stavrou S, Manzoni T, Iyer SS, Bibollet-Ruche F, Zhang W, Hahn BH, Browne EP, Ross SR. The effect of HIV-1 Vif polymorphisms on A3G anti-viral activity in an in vivo mouse model. Retrovirology 2016; 13:45. [PMID: 27363431 PMCID: PMC4929759 DOI: 10.1186/s12977-016-0280-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/22/2016] [Indexed: 11/10/2022] Open
Abstract
Humans encode seven APOBEC3 proteins (A-H), with A3G, 3F and 3H as the major factors restricting HIV-1 replication. HIV-1, however, encodes Vif, which counteracts A3 proteins by chaperoning them to the proteasome where they are degraded. Vif polymorphisms found in HIV-1s isolated from infected patients have varying anti-A3G potency when assayed in vitro, but there are few studies demonstrating this in in vivo models. Here, we created Friend murine leukemia viruses encoding vif alleles that were previously shown to differentially neutralize A3G in cell culture or that were originally found in primary HIV-1 isolates. Infection of transgenic mice expressing different levels of human A3G showed that these naturally occurring Vif variants differed in their ability to counteract A3G during in vivo infection, although the effects on viral replication were not identical to those seen in cultured cells. We also found that the polymorphic Vifs that attenuated viral replication reverted to wild type only in A3G transgenic mice. Finally, we found that the level of A3G-mediated deamination was inversely correlated with the level of viral replication. This animal model should be useful for studying the functional significance of naturally occurring vif polymorphisms, as well as viral evolution in the presence of A3G.
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Affiliation(s)
- Cristhian Cadena
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Spyridon Stavrou
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Microbiology and Immunology, University of Illinois at Chicago College of Medicine, Chicago, IL, 60612, USA
| | - Tomaz Manzoni
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shilpa S Iyer
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frederic Bibollet-Ruche
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Weiyu Zhang
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Beatrice H Hahn
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Edward P Browne
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Division of Infectious Diseases, Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Susan R Ross
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Microbiology and Immunology, University of Illinois at Chicago College of Medicine, Chicago, IL, 60612, USA.
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Interferon Alpha Subtype-Specific Suppression of HIV-1 Infection In Vivo. J Virol 2016; 90:6001-6013. [PMID: 27099312 DOI: 10.1128/jvi.00451-16] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/13/2016] [Indexed: 01/29/2023] Open
Abstract
UNLABELLED Although all 12 subtypes of human interferon alpha (IFN-α) bind the same receptor, recent results have demonstrated that they elicit unique host responses and display distinct efficacies in the control of different viral infections. The IFN-α2 subtype is currently in HIV-1 clinical trials, but it has not consistently reduced viral loads in HIV-1 patients and is not the most effective subtype against HIV-1 in vitro We now demonstrate in humanized mice that, when delivered at the same high clinical dose, the human IFN-α14 subtype has very potent anti-HIV-1 activity whereas IFN-α2 does not. In both postexposure prophylaxis and treatment of acute infections, IFN-α14, but not IFN-α2, significantly suppressed HIV-1 replication and proviral loads. Furthermore, HIV-1-induced immune hyperactivation, which is a prognosticator of disease progression, was reduced by IFN-α14 but not IFN-α2. Whereas ineffective IFN-α2 therapy was associated with CD8(+) T cell activation, successful IFN-α14 therapy was associated with increased intrinsic and innate immunity, including significantly higher induction of tetherin and MX2, increased APOBEC3G signature mutations in HIV-1 proviral DNA, and higher frequencies of TRAIL(+) NK cells. These results identify IFN-α14 as a potent new therapeutic that operates via mechanisms distinct from those of antiretroviral drugs. The ability of IFN-α14 to reduce both viremia and proviral loads in vivo suggests that it has strong potential as a component of a cure strategy for HIV-1 infections. The broad implication of these results is that the antiviral efficacy of each individual IFN-α subtype should be evaluated against the specific virus being treated. IMPORTANCE The naturally occurring antiviral protein IFN-α2 is used to treat hepatitis viruses but has proven rather ineffective against HIV in comparison to triple therapy with the antiretroviral (ARV) drugs. Although ARVs suppress the replication of HIV, they fail to completely clear infections. Since IFN-α acts by different mechanism than ARVs and has been shown to reduce HIV proviral loads, clinical trials are under way to test whether IFN-α2 combined with ARVs might eradicate HIV-1 infections. IFN-α is actually a family of 12 distinct proteins, and each IFN-α subtype has different efficacies toward different viruses. Here, we use mice that contain a human immune system, so they can be infected with HIV. With this model, we demonstrate that while IFN-α2 is only weakly effective against HIV, IFN-α14 is extremely potent. This discovery identifies IFN-α14 as a more powerful IFN-α subtype for use in combination therapy trials aimed toward an HIV cure.
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APOBEC3G and APOBEC3F Act in Concert To Extinguish HIV-1 Replication. J Virol 2016; 90:4681-4695. [PMID: 26912618 DOI: 10.1128/jvi.03275-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 02/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The multifunctional HIV-1 accessory protein Vif counters the antiviral activities of APOBEC3G (A3G) and APOBEC3F (A3F), and some Vifs counter stable alleles of APOBEC3H (A3H). Studies in humanized mice have shown that HIV-1 lacking Vif expression is not viable. Here, we look at the relative contributions of the three APOBEC3s to viral extinction. Inoculation of bone marrow/liver/thymus (BLT) mice with CCR5-tropic HIV-1JRCSF(JRCSF) expressing a vif gene inactive for A3G but not A3F degradation activity (JRCSFvifH42/43D) displayed either no or delayed replication. JRCSF expressing a vif gene mutated to inactivate A3F degradation but not A3G degradation (JRCSFvifW79S) always replicated to high viral loads with variable delays. JRCSF with vif mutated to lack both A3G and A3F degradation activities (JRCSFvifH42/43DW79S) failed to replicate, mimicking JRCSF without Vif expression (JRCSFΔvif). JRCSF and JRCSFvifH42/43D, but not JRCSFvifW79S or JRCSFvifH42/43DW79S, degraded APOBEC3D. With one exception, JRCSFs expressing mutant Vifs that replicated acquired enforced vif mutations. These mutations partially restored A3G or A3F degradation activity and fully replaced JRCSFvifH42/43D or JRCSFvifW79S by 10 weeks. Surprisingly, induced mutations temporally lagged behind high levels of virus in blood. In the exceptional case, JRCSFvifH42/43D replicated after a prolonged delay with no mutations in vif but instead a V27I mutation in the RNase H coding sequence. JRCSFvifH42/43D infections exhibited massive GG/AG mutations in pol viral DNA, but in viral RNA, there were no fixed mutations in the Gag or reverse transcriptase coding sequence. A3H did not contribute to viral extinction but, in combination with A3F, could delay JRCSF replication. A3H was also found to hypermutate viral DNA. IMPORTANCE Vif degradation of A3G and A3F enhances viral fitness, as virus with even a partially restored capacity for degradation outgrows JRCSFvifH42/43D and JRCSFvifW79S. Unexpectedly, fixation of mutations that replaced H42/43D or W79S in viral RNA lagged behind the appearance of high viral loads. In one exceptional JRCSFvifH42/43D infection, vif was unchanged but replication proceeded after a long delay. These results suggest that Vif binds and inhibits the non-cytosine deaminase activities of intact A3G and intact A3F, allowing JRCSFvifH42/43D and JRCSFvifW79S to replicate with reduced fitness. Subsequently, enhanced Vif function is acquired by enforced mutations. In infected cells, JRCSFΔvif and JRCSFvifH42/43DW79S are exposed to active A3F and A3G and fail to replicate. JRCSFvifH42/43D Vif degrades A3F and, in some cases, overcomes A3G mutagenic activity to replicate. Vif may have evolved to inhibit A3F and A3G by stoichiometric binding and subsequently acquired the ability to target these proteins to proteasomes.
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Yoshikawa R, Nakano Y, Yamada E, Izumi T, Misawa N, Koyanagi Y, Sato K. Species-specific differences in the ability of feline lentiviral Vif to degrade feline APOBEC3 proteins. Microbiol Immunol 2016; 60:272-9. [PMID: 26935128 PMCID: PMC5074269 DOI: 10.1111/1348-0421.12371] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/21/2016] [Accepted: 02/29/2016] [Indexed: 01/24/2023]
Abstract
How host-virus co-evolutionary relationships manifest is one of the most intriguing issues in virology. To address this topic, the mammal-lentivirus relationship can be considered as an interplay of cellular and viral proteins, particularly apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) and viral infectivity factor (Vif). APOBEC3s enzymatically restrict lentivirus replication, whereas Vif antagonizes the host anti-viral action mediated by APOBEC3. In this study, the focus was on the interplay between feline APOBEC3 proteins and two feline immunodeficiency viruses in cats and pumas. To our knowledge, this study provides the first evidence of non-primate lentiviral Vif being incapable of counteracting a natural host's anti-viral activity mediated via APOBEC3 protein.
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Affiliation(s)
- Rokusuke Yoshikawa
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
| | - Yusuke Nakano
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
| | - Eri Yamada
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
| | - Taisuke Izumi
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
- CRESTJapan Science and Technology AgencySaitama3220012Japan
| | - Naoko Misawa
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
| | - Yoshio Koyanagi
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
| | - Kei Sato
- Laboratory of Viral PathogenesisInstitute for Virus ResearchKyoto UniversityKyoto6068507
- CRESTJapan Science and Technology AgencySaitama3220012Japan
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Richards C, Albin JS, Demir Ö, Shaban NM, Luengas EM, Land AM, Anderson BD, Holten JR, Anderson JS, Harki DA, Amaro RE, Harris RS. The Binding Interface between Human APOBEC3F and HIV-1 Vif Elucidated by Genetic and Computational Approaches. Cell Rep 2015; 13:1781-8. [PMID: 26628363 DOI: 10.1016/j.celrep.2015.10.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 09/10/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022] Open
Abstract
APOBEC3 family DNA cytosine deaminases provide overlapping defenses against pathogen infections. However, most viruses have elaborate evasion mechanisms such as the HIV-1 Vif protein, which subverts cellular CBF-β and a polyubiquitin ligase complex to neutralize these enzymes. Despite advances in APOBEC3 and Vif biology, a full understanding of this direct host-pathogen conflict has been elusive. We combine virus adaptation and computational studies to interrogate the APOBEC3F-Vif interface and build a robust structural model. A recurring compensatory amino acid substitution from adaptation experiments provided an initial docking constraint, and microsecond molecular dynamic simulations optimized interface contacts. Virus infectivity experiments validated a long-lasting electrostatic interaction between APOBEC3F E289 and HIV-1 Vif R15. Taken together with mutagenesis results, we propose a wobble model to explain how HIV-1 Vif has evolved to bind different APOBEC3 enzymes and, more generally, how pathogens may evolve to escape innate host defenses.
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Affiliation(s)
- Christopher Richards
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - John S Albin
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Özlem Demir
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nadine M Shaban
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elizabeth M Luengas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Allison M Land
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brett D Anderson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - John R Holten
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - John S Anderson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel A Harki
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rommie E Amaro
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA.
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Huang J, Li X, Coelho-dos-Reis JGA, Zhang M, Mitchell R, Nogueira RT, Tsao T, Noe AR, Ayala R, Sahi V, Gutierrez GM, Nussenzweig V, Wilson JM, Nardin EH, Nussenzweig RS, Tsuji M. Human immune system mice immunized with Plasmodium falciparum circumsporozoite protein induce protective human humoral immunity against malaria. J Immunol Methods 2015; 427:42-50. [PMID: 26410104 DOI: 10.1016/j.jim.2015.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/17/2015] [Accepted: 09/23/2015] [Indexed: 12/28/2022]
Abstract
In this study, we developed human immune system (HIS) mice that possess functional human CD4+ T cells and B cells, named HIS-CD4/B mice. HIS-CD4/B mice were generated by first introducing HLA class II genes, including DR1 and DR4, along with genes encoding various human cytokines and human B cell activation factor (BAFF) to NSG mice by adeno-associated virus serotype 9 (AAV9) vectors, followed by engrafting human hematopoietic stem cells (HSCs). HIS-CD4/B mice, in which the reconstitution of human CD4+ T and B cells resembles to that of humans, produced a significant level of human IgG against Plasmodium falciparum circumsporozoite (PfCS) protein upon immunization. CD4+ T cells in HIS-CD4/B mice, which possess central and effector memory phenotypes like those in humans, are functional, since PfCS protein-specific human CD4+ T cells secreting IFN-γ and IL-2 were detected in immunized HIS-CD4/B mice. Lastly, PfCS protein-immunized HIS-CD4/B mice were protected from in vivo challenge with transgenic P. berghei sporozoites expressing the PfCS protein. The immune sera collected from protected HIS-CD4/B mice reacted against transgenic P. berghei sporozoites expressing the PfCS protein and also inhibited the parasite invasion into hepatocytes in vitro. Taken together, these studies show that our HIS-CD4/B mice could mount protective human anti-malaria immunity, consisting of human IgG and human CD4+ T cell responses both specific for a human malaria antigen.
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Affiliation(s)
- Jing Huang
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | - Xiangming Li
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | | | - Min Zhang
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Robert Mitchell
- Division of Parasitology, Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Raquel Tayar Nogueira
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | - Tiffany Tsao
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | | | | | - Vincent Sahi
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | | | - Victor Nussenzweig
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - James M Wilson
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elizabeth H Nardin
- Division of Parasitology, Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Ruth S Nussenzweig
- Division of Parasitology, Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Moriya Tsuji
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA.
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Kovarova M, Council OD, Date AA, Long JM, Nochii T, Belshan M, Shibata A, Vincent H, Baker CE, Thayer WO, Kraus G, Lachaud-Durand S, Williams P, Destache CJ, Garcia JV. Nanoformulations of Rilpivirine for Topical Pericoital and Systemic Coitus-Independent Administration Efficiently Prevent HIV Transmission. PLoS Pathog 2015; 11:e1005075. [PMID: 26271040 PMCID: PMC4536200 DOI: 10.1371/journal.ppat.1005075] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/08/2015] [Indexed: 01/11/2023] Open
Abstract
Vaginal HIV transmission accounts for the majority of new infections worldwide. Currently, multiple efforts to prevent HIV transmission are based on pre-exposure prophylaxis with various antiretroviral drugs. Here, we describe two novel nanoformulations of the reverse transcriptase inhibitor rilpivirine for pericoital and coitus-independent HIV prevention. Topically applied rilpivirine, encapsulated in PLGA nanoparticles, was delivered in a thermosensitive gel, which becomes solid at body temperature. PLGA nanoparticles with encapsulated rilpivirine coated the reproductive tract and offered significant protection to BLT humanized mice from a vaginal high-dose HIV-1 challenge. A different nanosuspension of crystalline rilpivirine (RPV LA), administered intramuscularly, protected BLT mice from a single vaginal high-dose HIV-1 challenge one week after drug administration. Using transmitted/founder viruses, which were previously shown to establish de novo infection in humans, we demonstrated that RPV LA offers significant protection from two consecutive high-dose HIV-1 challenges one and four weeks after drug administration. In this experiment, we also showed that, in certain cases, even in the presence of drug, HIV infection could occur without overt or detectable systemic replication until levels of drug were reduced. We also showed that infection in the presence of drug can result in acquisition of multiple viruses after subsequent exposures. These observations have important implications for the implementation of long-acting antiretroviral formulations for HIV prevention. They provide first evidence that occult infections can occur, despite the presence of sustained levels of antiretroviral drugs. Together, our results demonstrate that topically- or systemically administered rilpivirine offers significant coitus-dependent or coitus-independent protection from HIV infection. When taken consistently, PrEP has been shown to reduce the risk of HIV infection by up to 92% in people who are at high risk. However, PrEP is much less effective if it is not taken consistently. To improve adherence to the drug regimen, several new drug delivery systems, that include novel gel formulations and long-acting delivery systems, are being evaluated. In this manuscript, we used BLT humanized mice, an in vivo model of vaginal HIV transmission, to evaluate two novel delivery systems for HIV prevention. In the first approach, we combined the highly efficient encapsulation of antiretroviral drugs into nanoparticles with a thermosensitive gel that remains liquid at room temperature and solidifies at body temperature. Our results showed that this delivery system provided significant protection from HIV vaginal infection. In a second approach, we evaluated a long-acting nanoparticle formulation for coitus-independent protection from HIV acquisition. Our results showed that a single injection of the long-acting antiviral drug also resulted in reduced HIV infection. However, protection was not complete and transmission was concealed by a significant delay in the onset of plasma viremia that could result in superinfection by two different viruses administered up to four weeks apart.
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Affiliation(s)
- Martina Kovarova
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (MK); (JVG)
| | - Olivia D. Council
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Abhijit A. Date
- Department of Pharmacy Practice, Creighton University School of Pharmacy and Health Professions, Omaha, Nebraska, United States of America
| | - Julie M. Long
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Tomonori Nochii
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Michael Belshan
- Department of Pharmacy Practice, Creighton University School of Pharmacy and Health Professions, Omaha, Nebraska, United States of America
| | - Annemarie Shibata
- Department of Pharmacy Practice, Creighton University School of Pharmacy and Health Professions, Omaha, Nebraska, United States of America
| | - Heather Vincent
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Caroline E. Baker
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | - William O. Thayer
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
| | | | | | | | - Christopher J. Destache
- Department of Pharmacy Practice, Creighton University School of Pharmacy and Health Professions, Omaha, Nebraska, United States of America
| | - J. Victor Garcia
- Division of Infectious Diseases, Center for AIDS Research, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (MK); (JVG)
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Watkins RL, Foster JL, Garcia JV. In vivo analysis of Nef's role in HIV-1 replication, systemic T cell activation and CD4(+) T cell loss. Retrovirology 2015; 12:61. [PMID: 26169178 PMCID: PMC4501112 DOI: 10.1186/s12977-015-0187-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/29/2015] [Indexed: 11/21/2022] Open
Abstract
Background Nef is a multifunctional HIV-1 protein critical for progression to AIDS. Humans infected with nef(−) HIV-1 have greatly delayed or no disease consequences. We have contrasted nef(−) and nef(+) infection of BLT humanized mice to better characterize Nef’s pathogenic effects. Results Mice were inoculated with CCR5-tropic HIV-1JRCSF (JRCSF) or JRCSF with an irreversibly inactivated nef (JRCSFNefdd). In peripheral blood (PB), JRCSF exhibited high levels of viral RNA (peak viral loads of 4.71 × 106 ± 1.23 × 106 copies/ml) and a progressive, 75% loss of CD4+ T cells over 17 weeks. Similar losses were observed in CD4+ T cells from bone marrow, spleen, lymph node, lung and liver but thymocytes were not significantly decreased. JRCSFNefdd also had high peak viral loads (2.31 × 106 ± 1.67 × 106) but induced no loss of PB CD4+ T cells. In organs, JRCSFNefdd produced small, but significant, reductions in CD4+ T cell levels and did not affect the level of thymocytes. Uninfected mice have low levels of HLA-DR+CD38+CD8+ T cells in blood (1–2%). Six weeks post inoculation, JRCSF infection resulted in significantly elevated levels of activated CD8+ T cells (6.37 ± 1.07%). T cell activation coincided with PB CD4+ T cell loss which suggests a common Nef-dependent mechanism. At 12 weeks, in JRCSF infected animals PB T cell activation sharply increased to 19.7 ± 2.9% then subsided to 5.4 ± 1.4% at 14 weeks. HLA-DR+CD38+CD8+ T cell levels in JRCSFNefdd infected mice did not rise above 1–2% despite sustained high levels of viremia. Interestingly, we also noted that in mice engrafted with human tissue expressing a putative protective HLA-B allele (B42:01), JRCSFNefdd exhibited a substantial (200-fold) reduced viral load compared to JRCSF. Conclusions Nef expression was necessary for both systemic T cell activation and substantial CD4+ T cell loss from blood and tissues. JRCSFNefdd infection did not activate CD8+ T cells or reduce the level of CD4+ T cells in blood but did result in a small Nef-independent decrease in CD4+ T cells in organs. These observations strongly support the conclusion that viral pathogenicity is mostly driven by Nef. We also observed for the first time substantial host-specific suppression of HIV-1 replication in a small animal infection model. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0187-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Richard L Watkins
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
| | - John L Foster
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
| | - J Victor Garcia
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
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Simon V, Bloch N, Landau NR. Intrinsic host restrictions to HIV-1 and mechanisms of viral escape. Nat Immunol 2015; 16:546-53. [PMID: 25988886 PMCID: PMC6908429 DOI: 10.1038/ni.3156] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/24/2015] [Indexed: 02/06/2023]
Abstract
To replicate in their hosts, viruses have to navigate the complexities of the mammalian cell, co-opting mechanisms of cellular physiology while defeating restriction factors that are dedicated to halting their progression. Primate lentiviruses devote a relatively large portion of their coding capacity to counteracting restriction factors by encoding accessory proteins dedicated to neutralizing the antiviral function of these intracellular inhibitors. Research into the roles of the accessory proteins has revealed the existence of previously undetected intrinsic defenses, provided insight into the evolution of primate lentiviruses as they adapt to new species and uncovered new targets for the development of therapeutics. This Review discusses the biology of the restriction factors APOBEC3, SAMHD1 and tetherin and the viral accessory proteins that counteract them.
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Affiliation(s)
- Viviana Simon
- Department of Microbiology, The Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Nicolin Bloch
- Department of Microbiology, NYU School of Medicine, New York, New York, USA
| | - Nathaniel R Landau
- Department of Microbiology, NYU School of Medicine, New York, New York, USA
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Harris RS, Dudley JP. APOBECs and virus restriction. Virology 2015; 479-480:131-45. [PMID: 25818029 PMCID: PMC4424171 DOI: 10.1016/j.virol.2015.03.012] [Citation(s) in RCA: 384] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 02/10/2015] [Accepted: 03/04/2015] [Indexed: 12/22/2022]
Abstract
The APOBEC family of single-stranded DNA cytosine deaminases comprises a formidable arm of the vertebrate innate immune system. Pre-vertebrates express a single APOBEC, whereas some mammals produce as many as 11 enzymes. The APOBEC3 subfamily displays both copy number variation and polymorphisms, consistent with ongoing pathogenic pressures. These enzymes restrict the replication of many DNA-based parasites, such as exogenous viruses and endogenous transposable elements. APOBEC1 and activation-induced cytosine deaminase (AID) have specialized functions in RNA editing and antibody gene diversification, respectively, whereas APOBEC2 and APOBEC4 appear to have different functions. Nevertheless, the APOBEC family protects against both periodic viral zoonoses as well as exogenous and endogenous parasite replication. This review highlights viral pathogens that are restricted by APOBEC enzymes, but manage to escape through unique mechanisms. The sensitivity of viruses that lack counterdefense measures highlights the need to develop APOBEC-enabling small molecules as a new class of anti-viral drugs.
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Affiliation(s)
- Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, Institute for Molecular Virology, Center for Genome Engineering, and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Jaquelin P Dudley
- Department of Molecular Biosciences, Center for Infectious Disease, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, United States.
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ASK1 restores the antiviral activity of APOBEC3G by disrupting HIV-1 Vif-mediated counteraction. Nat Commun 2015; 6:6945. [PMID: 25901786 PMCID: PMC4423214 DOI: 10.1038/ncomms7945] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/17/2015] [Indexed: 12/24/2022] Open
Abstract
APOBEC3G (A3G) is an innate antiviral restriction factor that strongly inhibits the replication of human immunodeficiency virus type 1 (HIV-1). An HIV-1 accessory protein, Vif, hijacks the host ubiquitin–proteasome system to execute A3G degradation. Identification of the host pathways that obstruct the action of Vif could provide a new strategy for blocking viral replication. We demonstrate here that the host protein ASK1 (apoptosis signal-regulating kinase 1) interferes with the counteraction by Vif and revitalizes A3G-mediated viral restriction. ASK1 binds the BC-box of Vif, thereby disrupting the assembly of the Vif–ubiquitin ligase complex. Consequently, ASK1 stabilizes A3G and promotes its incorporation into viral particles, ultimately reducing viral infectivity. Furthermore, treatment with the antiretroviral drug AZT (zidovudine) induces ASK1 expression and restores the antiviral activity of A3G in HIV-1-infected cells. This study thus demonstrates a distinct function of ASK1 in restoring the host antiviral system that can be enhanced by AZT treatment. The human protein APOBEC3G (A3G) inhibits HIV-1 replication, but the viral protein Vif counteracts by inducing A3G degradation. Here Miyakawa et al. show that the antiretroviral drug AZT restores A3G function in vitro by stimulating expression of a host protein, ASK1, which interferes with the action of Vif.
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Yamada E, Yoshikawa R, Nakano Y, Misawa N, Koyanagi Y, Sato K. Impacts of humanized mouse models on the investigation of HIV-1 infection: illuminating the roles of viral accessory proteins in vivo. Viruses 2015; 7:1373-90. [PMID: 25807049 PMCID: PMC4379576 DOI: 10.3390/v7031373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/26/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes four accessory genes: vif, vpu, vpr, and nef. Recent investigations using in vitro cell culture systems have shed light on the roles of these HIV-1 accessory proteins, Vif, Vpr, Vpu, and Nef, in counteracting, modulating, and evading various cellular factors that are responsible for anti-HIV-1 intrinsic immunity. However, since humans are the exclusive target for HIV-1 infection, conventional animal models are incapable of mimicking the dynamics of HIV-1 infection in vivo. Moreover, the effects of HIV-1 accessory proteins on viral infection in vivo remain unclear. To elucidate the roles of HIV-1 accessory proteins in the dynamics of viral infection in vivo, humanized mouse models, in which the mice are xenotransplanted with human hematopoietic stem cells, has been utilized. This review describes the current knowledge of the roles of HIV-1 accessory proteins in viral infection, replication, and pathogenicity in vivo, which are revealed by the studies using humanized mouse models.
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Affiliation(s)
- Eri Yamada
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Rokusuke Yoshikawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yusuke Nakano
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Naoko Misawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Kei Sato
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
- CREST, Japan Science and Technology Agency, Saitama 3220012, Japan.
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Li Y, Di Santo JP. Probing Human NK Cell Biology Using Human Immune System (HIS) Mice. Curr Top Microbiol Immunol 2015; 395:191-208. [PMID: 26459320 DOI: 10.1007/82_2015_488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Our incomplete understanding of the mechanisms that orchestrate human lymphocyte differentiation and condition human immune responses is in part due to the limited access to normal human tissue samples that can inform on these complex processes. In addition, in vitro culture conditions fail to recapitulate the three-dimensional microenvironments that influence cell-cell interactions and impact on immune outcomes. Small animals provide a preclinical model to dissect and probe immunity and over the past decades, development of immunodeficient hosts that can be engrafted with human hematopoietic precursors and mature cells have led to the development of new in vivo models to study human lymphocyte development and function. Natural killer (NK) cells are implicated in the recognition and elimination of pathogen-infected and transformed cells and belong to a family of diverse innate lymphoid cells (ILCs) that provide early immune defense against disease. Here, we summarize the use of humanized mouse models for the study of NK cell and group 1 ILCs and their respective roles in immunity and tissue homeostasis.
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Affiliation(s)
- Yan Li
- Innate Immunity Unit, Institut Pasteur, 25 rue du Docteur Roux, Paris, 75724, France.,Inserm U668, Paris, France
| | - James P Di Santo
- Innate Immunity Unit, Institut Pasteur, 25 rue du Docteur Roux, Paris, 75724, France. .,Inserm U668, Paris, France.
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Sato K, Takeuchi JS, Misawa N, Izumi T, Kobayashi T, Kimura Y, Iwami S, Takaori-Kondo A, Hu WS, Aihara K, Ito M, An DS, Pathak VK, Koyanagi Y. APOBEC3D and APOBEC3F potently promote HIV-1 diversification and evolution in humanized mouse model. PLoS Pathog 2014; 10:e1004453. [PMID: 25330146 PMCID: PMC4199767 DOI: 10.1371/journal.ppat.1004453] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/05/2014] [Indexed: 12/02/2022] Open
Abstract
Several APOBEC3 proteins, particularly APOBEC3D, APOBEC3F, and APOBEC3G, induce G-to-A hypermutations in HIV-1 genome, and abrogate viral replication in experimental systems, but their relative contributions to controlling viral replication and viral genetic variation in vivo have not been elucidated. On the other hand, an HIV-1-encoded protein, Vif, can degrade these APOBEC3 proteins via a ubiquitin/proteasome pathway. Although APOBEC3 proteins have been widely considered as potent restriction factors against HIV-1, it remains unclear which endogenous APOBEC3 protein(s) affect HIV-1 propagation in vivo. Here we use a humanized mouse model and HIV-1 with mutations in Vif motifs that are responsible for specific APOBEC3 interactions, DRMR/AAAA (4A) or YRHHY/AAAAA (5A), and demonstrate that endogenous APOBEC3D/F and APOBEC3G exert strong anti-HIV-1 activity in vivo. We also show that the growth kinetics of 4A HIV-1 negatively correlated with the expression level of APOBEC3F. Moreover, single genome sequencing analyses of viral RNA in plasma of infected mice reveal that 4A HIV-1 is specifically and significantly diversified. Furthermore, a mutated virus that is capable of using both CCR5 and CXCR4 as entry coreceptor is specifically detected in 4A HIV-1-infected mice. Taken together, our results demonstrate that APOBEC3D/F and APOBEC3G fundamentally work as restriction factors against HIV-1 in vivo, but at the same time, that APOBEC3D and APOBEC3F are capable of promoting viral diversification and evolution in vivo. Mutation can produce three outcomes in viruses: detrimental, neutral, or beneficial. The first one leads to abrogation of virus replication because of error catastrophe, while the last one lets the virus escape from anti-viral immune system or adapt to the host. Human APOBEC3D, APOBEC3F, and APOBEC3G are cellular cytidine deaminases which cause G-to-A mutations in HIV-1 genome. Here we use a humanized mouse model and demonstrate that endogenous APOBEC3F and APOBEC3G induce G-to-A hypermutation in viral genomes and exert strong anti-HIV-1 activity in vivo. We also reveal that endogenous APOBEC3D and/or APOBEC3F induce viral diversification, which can lead to the emergence of a mutated virus that converts its coreceptor usage. Our results suggest that APOBEC3D and APOBEC3F are capable of promoting viral diversification and functional evolution in vivo.
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Affiliation(s)
- Kei Sato
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
- * E-mail:
| | - Junko S. Takeuchi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
| | - Naoko Misawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
| | - Taisuke Izumi
- Viral Mutation Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Tomoko Kobayashi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
| | - Yuichi Kimura
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
| | - Shingo Iwami
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Kazuyuki Aihara
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, Japan
- Graduate School of Information Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Mamoru Ito
- Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan
| | - Dong Sung An
- Division of Hematology and Oncology, University of California, Los Angeles, Los Angeles, California, United States of America
- School of Nursing, University of California, Los Angeles, Los Angeles, California, United States of America
- AIDS Institute, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Vinay K. Pathak
- Viral Mutation Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto, Japan
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Barrett BS, Guo K, Harper MS, Li SX, Heilman KJ, Davidson NO, Santiago ML. Reassessment of murine APOBEC1 as a retrovirus restriction factor in vivo. Virology 2014; 468-470:601-608. [PMID: 25303118 DOI: 10.1016/j.virol.2014.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 09/02/2014] [Accepted: 09/06/2014] [Indexed: 12/21/2022]
Abstract
APOBEC1 is a cytidine deaminase involved in cholesterol metabolism that has been linked to retrovirus restriction, analogous to the evolutionarily-related APOBEC3 proteins. In particular, murine APOBEC1 was shown to inhibit Friend retrovirus (FV) in vitro, generating high levels of C-to-T and G-to-A mutations. These observations raised the possibility that FV infection might be altered in APOBEC1-null mice. To examine this question directly, we infected wild-type and APOBEC1-null mice with FV complex and evaluated acute infection levels. Surprisingly, APOBEC1-null mice exhibited similar cellular infection levels and plasma viremia relative to wild-type mice. Moreover, next-generation sequencing analyses revealed that in contrast to APOBEC3, APOBEC1 did not enhance retroviral C-to-T and G-to-A mutational frequencies in genomic DNA. Thus, APOBEC1 neither inhibited nor significantly drove the molecular evolution of FV in vivo. Our findings reinforce that not all retrovirus restriction factors characterized as potent in vitro may be functionally relevant in vivo.
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Affiliation(s)
- Bradley S Barrett
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
| | - Kejun Guo
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
| | - Michael S Harper
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA; Department of Immunology and Microbiology, University of Colorado Denver, Aurora, CO 80045, USA
| | - Sam X Li
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA; Department of Immunology and Microbiology, University of Colorado Denver, Aurora, CO 80045, USA
| | - Karl J Heilman
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
| | - Nicholas O Davidson
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Mario L Santiago
- Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA; Department of Immunology and Microbiology, University of Colorado Denver, Aurora, CO 80045, USA.
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Martinez-Torres F, Nochi T, Wahl A, Garcia JV, Denton PW. Hypogammaglobulinemia in BLT humanized mice--an animal model of primary antibody deficiency. PLoS One 2014; 9:e108663. [PMID: 25271886 PMCID: PMC4182704 DOI: 10.1371/journal.pone.0108663] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 08/24/2014] [Indexed: 12/29/2022] Open
Abstract
Primary antibody deficiencies present clinically as reduced or absent plasma antibodies without another identified disorder that could explain the low immunoglobulin levels. Bone marrow-liver-thymus (BLT) humanized mice also exhibit primary antibody deficiency or hypogammaglobulinemia. Comprehensive characterization of B cell development and differentiation in BLT mice revealed other key parallels with primary immunodeficiency patients. We found that B cell ontogeny was normal in the bone marrow of BLT mice but observed an absence of switched memory B cells in the periphery. PC-KLH immunizations led to the presence of switched memory B cells in immunized BLT mice although plasma cells producing PC- or KLH- specific IgG were not detected in tissues. Overall, we have identified the following parallels between the humoral immune systems of primary antibody deficiency patients and those in BLT mice that make this in vivo model a robust and translational experimental platform for gaining a greater understanding of this heterogeneous array of humoral immunodeficiency disorders in humans: (i) hypogammaglobulinemia; (ii) normal B cell ontogeny in bone marrow; and (iii) poor antigen-specific IgG response to immunization. Furthermore, the development of strategies to overcome these humoral immune aberrations in BLT mice may in turn provide insights into the pathogenesis of some primary antibody deficiency patients which could lead to novel clinical interventions for improved humoral immune function.
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Affiliation(s)
- Francisco Martinez-Torres
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Tomonori Nochi
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Angela Wahl
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
| | - J. Victor Garcia
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (JVG); (PWD)
| | - Paul W. Denton
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail: (JVG); (PWD)
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van Montfoort N, Olagnier D, Hiscott J. Unmasking immune sensing of retroviruses: interplay between innate sensors and host effectors. Cytokine Growth Factor Rev 2014; 25:657-68. [PMID: 25240798 DOI: 10.1016/j.cytogfr.2014.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Retroviruses can selectively trigger an array of innate immune responses through various PRR. The identification and the characterization of the molecular basis of retroviral DNA sensing by the DNA sensors IFI16 and cGAS has been one of the most exciting developments in viral immunology in recent years. DNA sensing by these cytosolic sensors not only leads to the initiation of the type I interferon (IFN) antiviral response and the induction of the inflammatory response, but also triggers cell death mechanisms including pyroptosis and apoptosis in retrovirus-infected cells, thereby providing important insights into the pathophysiology of chronic retroviral infection. Host restriction factors such as SAMHD1 and Trex1 play important roles in regulating innate immune sensing, and have led to the idea that innate immune defense and host restriction actually converge at different levels to determine the outcome of retroviral infection. In this review, we discuss the sensing of retroviruses by cytosolic DNA sensors, the relevance of host factors during retroviral infection, and the interplay between host factors and the innate antiviral response in different cell types, within the context of two human pathogenic retroviruses - human immunodeficiency virus (HIV-1) and human T cell-leukemia virus type I (HTLV-1).
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Affiliation(s)
- Nadine van Montfoort
- Vaccine & Gene Therapy Institute of Florida, 9801 Discovery Way, Port Saint Lucie, FL 34987, USA
| | - David Olagnier
- Vaccine & Gene Therapy Institute of Florida, 9801 Discovery Way, Port Saint Lucie, FL 34987, USA
| | - John Hiscott
- Vaccine & Gene Therapy Institute of Florida, 9801 Discovery Way, Port Saint Lucie, FL 34987, USA.
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Stavrou S, Crawford D, Blouch K, Browne EP, Kohli RM, Ross SR. Different modes of retrovirus restriction by human APOBEC3A and APOBEC3G in vivo. PLoS Pathog 2014; 10:e1004145. [PMID: 24851906 PMCID: PMC4031197 DOI: 10.1371/journal.ppat.1004145] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/12/2014] [Indexed: 12/22/2022] Open
Abstract
The apolipoprotein B editing complex 3 (A3) cytidine deaminases are among the most highly evolutionarily selected retroviral restriction factors, both in terms of gene copy number and sequence diversity. Primate genomes encode seven A3 genes, and while A3F and 3G are widely recognized as important in the restriction of HIV, the role of the other genes, particularly A3A, is not as clear. Indeed, since human cells can express multiple A3 genes, and because of the lack of an experimentally tractable model, it is difficult to dissect the individual contribution of each gene to virus restriction in vivo. To overcome this problem, we generated human A3A and A3G transgenic mice on a mouse A3 knockout background. Using these mice, we demonstrate that both A3A and A3G restrict infection by murine retroviruses but by different mechanisms: A3G was packaged into virions and caused extensive deamination of the retrovirus genomes while A3A was not packaged and instead restricted infection when expressed in target cells. Additionally, we show that a murine leukemia virus engineered to express HIV Vif overcame the A3G-mediated restriction, thereby creating a novel model for studying the interaction between these proteins. We have thus developed an in vivo system for understanding how human A3 proteins use different modes of restriction, as well as a means for testing therapies that disrupt HIV Vif-A3G interactions. APOBEC3 genes are part of the host's arsenal against virus infections. Humans have 7 APOBEC3 genes and determining how each specifically functions to inhibit retroviruses like HIV is complicated, because all 7 can be produced in a given cell type or tissue. This is important, because some viruses make their own factors, such as the HIV Vif protein, that block the anti-viral activity of APOBEC3 proteins. Moreover, there is interest in developing anti-viral therapeutics that enhance the action of APOBEC3 proteins. To overcome this limitation, we made transgenic mice that express two of the human proteins, APOBEC3A and APOBEC3G in mice that do not express their own APOBEC3. These mice were able to effectively block infection by several mouse retroviruses. Moreover, we found that APOBEC3A and APOBEC3G used different mechanisms to block infection in vivo. These transgenic mice have the potential to increase our understanding of how the human proteins function to restrict virus infection in vivo and should be useful for the development of therapeutics that enhance APOBEC3 proteins' antiviral function.
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Affiliation(s)
- Spyridon Stavrou
- Department of Microbiology, Institute for Immunology and Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Daniel Crawford
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kristin Blouch
- Department of Microbiology, Institute for Immunology and Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Edward P. Browne
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Rahul M. Kohli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Susan R. Ross
- Department of Microbiology, Institute for Immunology and Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Desimmie BA, Delviks-Frankenberrry KA, Burdick RC, Qi D, Izumi T, Pathak VK. Multiple APOBEC3 restriction factors for HIV-1 and one Vif to rule them all. J Mol Biol 2014; 426:1220-45. [PMID: 24189052 PMCID: PMC3943811 DOI: 10.1016/j.jmb.2013.10.033] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 12/11/2022]
Abstract
Several members of the APOBEC3 family of cellular restriction factors provide intrinsic immunity to the host against viral infection. Specifically, APOBEC3DE, APOBEC3F, APOBEC3G, and APOBEC3H haplotypes II, V, and VII provide protection against HIV-1Δvif through hypermutation of the viral genome, inhibition of reverse transcription, and inhibition of viral DNA integration into the host genome. HIV-1 counteracts APOBEC3 proteins by encoding the viral protein Vif, which contains distinct domains that specifically interact with these APOBEC3 proteins to ensure their proteasomal degradation, allowing virus replication to proceed. Here, we review our current understanding of APOBEC3 structure, editing and non-editing mechanisms of APOBEC3-mediated restriction, Vif-APOBEC3 interactions that trigger APOBEC3 degradation, and the contribution of APOBEC3 proteins to restriction and control of HIV-1 replication in infected patients.
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Affiliation(s)
- Belete A Desimmie
- Viral Mutation Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | | | - Ryan C Burdick
- Viral Mutation Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - DongFei Qi
- Viral Mutation Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Taisuke Izumi
- Viral Mutation Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Vinay K Pathak
- Viral Mutation Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
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Quantification of deaminase activity-dependent and -independent restriction of HIV-1 replication mediated by APOBEC3F and APOBEC3G through experimental-mathematical investigation. J Virol 2014; 88:5881-7. [PMID: 24623435 DOI: 10.1128/jvi.00062-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
APOBEC3F and APOBEC3G cytidine deaminases potently inhibit human immunodeficiency virus type 1 (HIV-1) replication by enzymatically inserting G-to-A mutations in viral DNA and/or impairing viral reverse transcription independently of their deaminase activity. Through experimental and mathematical investigation, here we quantitatively demonstrate that 99.3% of the antiviral effect of APOBEC3G is dependent on its deaminase activity, whereas 30.2% of the antiviral effect of APOBEC3F is attributed to deaminase-independent ability. This is the first report quantitatively elucidating how APOBEC3F and APOBEC3G differ in their anti-HIV-1 modes.
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Wang X, Ao Z, Danappa Jayappa K, Shi B, Kobinger G, Yao X. R88-APOBEC3Gm Inhibits the Replication of Both Drug-resistant Strains of HIV-1 and Viruses Produced From Latently Infected Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e151. [PMID: 24594845 PMCID: PMC4027983 DOI: 10.1038/mtna.2014.2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 01/14/2014] [Indexed: 12/30/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) drug resistance and the latent reservoir are the two major obstacles to effectively controlling and curing HIV-1 infection. Therefore, it is critical to develop therapeutic strategies specifically targeting these two obstacles. Recently, we described a novel anti-HIV approach based on a modified human intrinsic restriction factor, R88-APOBEC3G (R88-A3G). In this study, we further characterized the antiviral potential of R88-A3GD128K (R88-A3Gm) against drug-resistant strains of HIV-1 and viruses produced from latently infected cells. We delivered R88-A3Gm into target cells using a doxycycline (Dox)-inducible lentiviral vector and demonstrated that its expression and antiviral activity were highly regulated by Dox. In the presence of Dox, R88-A3Gm–transduced T cells were resistant to infection caused by wild-type and various drug-resistant strains of HIV-1. Moreover, when the R88-A3Gm–expressing vector was transduced into the HIV-1 latently infected ACH-2 cell line or human CD4+ T cells, on activation by phorbol-12-myristate-13-acetate or phytohemaglutinin, R88-A3Gm was able to curtail the replication of progeny viruses. Altogether, these data clearly indicate that R88-A3Gm is a highly potent HIV-1 inhibitor, and R88-A3Gm–based anti-HIV gene therapy is capable of targeting both active and latent HIV-1–infected cells to prevent subsequent viral replication and dissemination.
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Affiliation(s)
- Xiaoxia Wang
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Zhujun Ao
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kallesh Danappa Jayappa
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Bei Shi
- Zunyi Medical College, Zunyi, Guizhou, China
| | - Gary Kobinger
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Xiaojian Yao
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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Denton PW, Long JM, Wietgrefe SW, Sykes C, Spagnuolo RA, Snyder OD, Perkey K, Archin NM, Choudhary SK, Yang K, Hudgens MG, Pastan I, Haase AT, Kashuba AD, Berger EA, Margolis DM, Garcia JV. Targeted cytotoxic therapy kills persisting HIV infected cells during ART. PLoS Pathog 2014; 10:e1003872. [PMID: 24415939 PMCID: PMC3887103 DOI: 10.1371/journal.ppat.1003872] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/22/2013] [Indexed: 11/18/2022] Open
Abstract
Antiretroviral therapy (ART) can reduce HIV levels in plasma to undetectable levels, but rather little is known about the effects of ART outside of the peripheral blood regarding persistent virus production in tissue reservoirs. Understanding the dynamics of ART-induced reductions in viral RNA (vRNA) levels throughout the body is important for the development of strategies to eradicate infectious HIV from patients. Essential to a successful eradication therapy is a component capable of killing persisting HIV infected cells during ART. Therefore, we determined the in vivo efficacy of a targeted cytotoxic therapy to kill infected cells that persist despite long-term ART. For this purpose, we first characterized the impact of ART on HIV RNA levels in multiple organs of bone marrow-liver-thymus (BLT) humanized mice and found that antiretroviral drug penetration and activity was sufficient to reduce, but not eliminate, HIV production in each tissue tested. For targeted cytotoxic killing of these persistent vRNA(+) cells, we treated BLT mice undergoing ART with an HIV-specific immunotoxin. We found that compared to ART alone, this agent profoundly depleted productively infected cells systemically. These results offer proof-of-concept that targeted cytotoxic therapies can be effective components of HIV eradication strategies.
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Affiliation(s)
- Paul W. Denton
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Julie M. Long
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Stephen W. Wietgrefe
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Craig Sykes
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Rae Ann Spagnuolo
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Olivia D. Snyder
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Katherine Perkey
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Nancie M. Archin
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Shailesh K. Choudhary
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Kuo Yang
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Michael G. Hudgens
- Department of Biostatistics, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Ira Pastan
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ashley T. Haase
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Angela D. Kashuba
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Edward A. Berger
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David M. Margolis
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - J. Victor Garcia
- Division of Infectious Diseases, Department of Medicine, UNC Center for AIDS Research, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Hassan MA, Butty V, Jensen KDC, Saeij JPJ. The genetic basis for individual differences in mRNA splicing and APOBEC1 editing activity in murine macrophages. Genome Res 2013; 24:377-89. [PMID: 24249727 PMCID: PMC3941103 DOI: 10.1101/gr.166033.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Alternative splicing and mRNA editing are known to contribute to transcriptome diversity. Although alternative splicing is pervasive and contributes to a variety of pathologies, including cancer, the genetic context for individual differences in isoform usage is still evolving. Similarly, although mRNA editing is ubiquitous and associated with important biological processes such as intracellular viral replication and cancer development, individual variations in mRNA editing and the genetic transmissibility of mRNA editing are equivocal. Here, we have used linkage analysis to show that both mRNA editing and alternative splicing are regulated by the macrophage genetic background and environmental cues. We show that distinct loci, potentially harboring variable splice factors, regulate the splicing of multiple transcripts. Additionally, we show that individual genetic variability at the Apobec1 locus results in differential rates of C-to-U(T) editing in murine macrophages; with mouse strains expressing mostly a truncated alternative transcript isoform of Apobec1 exhibiting lower rates of editing. As a proof of concept, we have used linkage analysis to identify 36 high-confidence novel edited sites. These results provide a novel and complementary method that can be used to identify C-to-U editing sites in individuals segregating at specific loci and show that, beyond DNA sequence and structural changes, differential isoform usage and mRNA editing can contribute to intra-species genomic and phenotypic diversity.
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Affiliation(s)
- Musa A Hassan
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Watkins RL, Zou W, Denton PW, Krisko JF, Foster JL, Garcia JV. In vivo analysis of highly conserved Nef activities in HIV-1 replication and pathogenesis. Retrovirology 2013; 10:125. [PMID: 24172637 PMCID: PMC3907037 DOI: 10.1186/1742-4690-10-125] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/23/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The HIV-1 accessory protein, Nef, is decisive for progression to AIDS. In vitro characterization of the protein has described many Nef activities of unknown in vivo significance including CD4 downregulation and a number of activities that depend on Nef interacting with host SH3 domain proteins. Here, we use the BLT humanized mouse model of HIV-1 infection to assess their impact on viral replication and pathogenesis and the selection pressure to restore these activities using enforced in vivo evolution. RESULTS We followed the evolution of HIV-1LAI (LAI) with a frame-shifted nef (LAINeffs) during infection of BLT mice. LAINeffs was rapidly replaced in blood by virus with short deletions in nef that restored the open reading frame (LAINeffs∆-1 and LAINeffs∆-13). Subsequently, LAINeffs∆-1 was often replaced by wild type LAI. Unexpectedly, LAINeffs∆-1 and LAINeffs∆-13 Nefs were specifically defective for CD4 downregulation activity. Viruses with these mutant nefs were used to infect BLT mice. LAINeffs∆-1 and LAINeffs∆-13 exhibited three-fold reduced viral replication (compared to LAI) and a 50% reduction of systemic CD4+ T cells (>90% for LAI) demonstrating the importance of CD4 downregulation. These results also demonstrate that functions other than CD4 downregulation enhanced viral replication and pathogenesis of LAINeffs∆-1 and LAINeffs∆-13 compared to LAINeffs. To gain insight into the nature of these activities, we constructed the double mutant P72A/P75A. Multiple Nef activities can be negated by mutating the SH3 domain binding site (P72Q73V74P75L76R77) to P72A/P75A and this mutation does not affect CD4 downregulation. Virus with nef mutated to P72A/P75A closely resembled the wild-type virus in vivo as viral replication and pathogenesis was not significantly altered. Unlike LAINeffs described above, the P72A/P75A mutation had a very weak tendency to revert to wild type sequence. CONCLUSIONS The in vivo phenotype of Nef is significantly dependent on CD4 downregulation but minimally on the numerous Nef activities that require an intact SH3 domain binding motif. These results suggest that CD4 downregulation plus one or more unknown Nef activities contribute to enhanced viral replication and pathogenesis and are suitable targets for anti-HIV therapy. Enforced evolution studies in BLT mice will greatly facilitate identification of these critical activities.
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Affiliation(s)
- Richard L Watkins
- Division of Infectious Diseases, Center for AIDS Research, 2042 Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC 27599-7042, USA.
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Watkins RL, Zou W, Denton PW, Krisko JF, Foster JL, Garcia JV. In vivo analysis of highly conserved Nef activities in HIV-1 replication and pathogenesis. Retrovirology 2013. [PMID: 24172637 DOI: 10.1186/742-4690-10-125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
BACKGROUND The HIV-1 accessory protein, Nef, is decisive for progression to AIDS. In vitro characterization of the protein has described many Nef activities of unknown in vivo significance including CD4 downregulation and a number of activities that depend on Nef interacting with host SH3 domain proteins. Here, we use the BLT humanized mouse model of HIV-1 infection to assess their impact on viral replication and pathogenesis and the selection pressure to restore these activities using enforced in vivo evolution. RESULTS We followed the evolution of HIV-1LAI (LAI) with a frame-shifted nef (LAINeffs) during infection of BLT mice. LAINeffs was rapidly replaced in blood by virus with short deletions in nef that restored the open reading frame (LAINeffs∆-1 and LAINeffs∆-13). Subsequently, LAINeffs∆-1 was often replaced by wild type LAI. Unexpectedly, LAINeffs∆-1 and LAINeffs∆-13 Nefs were specifically defective for CD4 downregulation activity. Viruses with these mutant nefs were used to infect BLT mice. LAINeffs∆-1 and LAINeffs∆-13 exhibited three-fold reduced viral replication (compared to LAI) and a 50% reduction of systemic CD4+ T cells (>90% for LAI) demonstrating the importance of CD4 downregulation. These results also demonstrate that functions other than CD4 downregulation enhanced viral replication and pathogenesis of LAINeffs∆-1 and LAINeffs∆-13 compared to LAINeffs. To gain insight into the nature of these activities, we constructed the double mutant P72A/P75A. Multiple Nef activities can be negated by mutating the SH3 domain binding site (P72Q73V74P75L76R77) to P72A/P75A and this mutation does not affect CD4 downregulation. Virus with nef mutated to P72A/P75A closely resembled the wild-type virus in vivo as viral replication and pathogenesis was not significantly altered. Unlike LAINeffs described above, the P72A/P75A mutation had a very weak tendency to revert to wild type sequence. CONCLUSIONS The in vivo phenotype of Nef is significantly dependent on CD4 downregulation but minimally on the numerous Nef activities that require an intact SH3 domain binding motif. These results suggest that CD4 downregulation plus one or more unknown Nef activities contribute to enhanced viral replication and pathogenesis and are suitable targets for anti-HIV therapy. Enforced evolution studies in BLT mice will greatly facilitate identification of these critical activities.
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Affiliation(s)
- Richard L Watkins
- Division of Infectious Diseases, Center for AIDS Research, 2042 Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC 27599-7042, USA.
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Leung C, Chijioke O, Gujer C, Chatterjee B, Antsiferova O, Landtwing V, McHugh D, Raykova A, Münz C. Infectious diseases in humanized mice. Eur J Immunol 2013; 43:2246-54. [PMID: 23913412 DOI: 10.1002/eji.201343815] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/23/2013] [Accepted: 07/31/2013] [Indexed: 12/15/2022]
Abstract
Despite many theoretical incompatibilities between mouse and human cells, mice with reconstituted human immune system components contain nearly all human leukocyte populations. Accordingly, several human-tropic pathogens have been investigated in these in vivo models of the human immune system, including viruses such as human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV), as well as bacteria such as Mycobacterium tuberculosis and Salmonella enterica Typhi. While these studies initially aimed to establish similarities in the pathogenesis of infections between these models and the pathobiology in patients, recent investigations have provided new and interesting functional insights into the protective value of certain immune compartments and altered pathology upon mutant pathogen infections. As more tools and methodologies are developed to make these models more versatile to study human immune responses in vivo, such improvements build toward small animal models with human immune components, which could predict immune responses to therapies and vaccination in human patients.
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Affiliation(s)
- Carol Leung
- Department of Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
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