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Law EK, Sieuwerts AM, LaPara K, Leonard B, Starrett GJ, Molan AM, Temiz NA, Vogel RI, Meijer-van Gelder ME, Sweep FCGJ, Span PN, Foekens JA, Martens JWM, Yee D, Harris RS. The DNA cytosine deaminase APOBEC3B promotes tamoxifen resistance in ER-positive breast cancer. SCIENCE ADVANCES 2016; 2:e1601737. [PMID: 27730215 PMCID: PMC5055383 DOI: 10.1126/sciadv.1601737] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 08/31/2016] [Indexed: 05/27/2023]
Abstract
Breast tumors often display extreme genetic heterogeneity characterized by hundreds of gross chromosomal aberrations and tens of thousands of somatic mutations. Tumor evolution is thought to be ongoing and driven by multiple mutagenic processes. A major outstanding question is whether primary tumors have preexisting mutations for therapy resistance or whether additional DNA damage and mutagenesis are necessary. Drug resistance is a key measure of tumor evolvability. If a resistance mutation preexists at the time of primary tumor presentation, then the intended therapy is likely to fail. However, if resistance does not preexist, then ongoing mutational processes still have the potential to undermine therapeutic efficacy. The antiviral enzyme APOBEC3B (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3B) preferentially deaminates DNA C-to-U, which results in signature C-to-T and C-to-G mutations commonly observed in breast tumors. We use clinical data and xenograft experiments to ask whether APOBEC3B contributes to ongoing breast tumor evolution and resistance to the selective estrogen receptor modulator, tamoxifen. First, APOBEC3B levels in primary estrogen receptor-positive (ER+) breast tumors inversely correlate with the clinical benefit of tamoxifen in the treatment of metastatic ER+ disease. Second, APOBEC3B depletion in an ER+ breast cancer cell line results in prolonged tamoxifen responses in murine xenograft experiments. Third, APOBEC3B overexpression accelerates the development of tamoxifen resistance in murine xenograft experiments by a mechanism that requires the enzyme's catalytic activity. These studies combine to indicate that APOBEC3B promotes drug resistance in breast cancer and that inhibiting APOBEC3B-dependent tumor evolvability may be an effective strategy to improve efficacies of targeted cancer therapies.
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Affiliation(s)
- Emily K. Law
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Anieta M. Sieuwerts
- Department of Medical Oncology and Cancer Genomics Netherlands, Erasmus MC Cancer Institute, 3015 GE Rotterdam, Netherlands
| | - Kelly LaPara
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brandon Leonard
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gabriel J. Starrett
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Amy M. Molan
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Nuri A. Temiz
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rachel Isaksson Vogel
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Division of Gynecologic Oncology, Department of Obstetrics, Gynecology and Women’s Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Marion E. Meijer-van Gelder
- Department of Medical Oncology and Cancer Genomics Netherlands, Erasmus MC Cancer Institute, 3015 GE Rotterdam, Netherlands
| | - Fred C. G. J. Sweep
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Paul N. Span
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, Netherlands
| | - John A. Foekens
- Department of Medical Oncology and Cancer Genomics Netherlands, Erasmus MC Cancer Institute, 3015 GE Rotterdam, Netherlands
| | - John W. M. Martens
- Department of Medical Oncology and Cancer Genomics Netherlands, Erasmus MC Cancer Institute, 3015 GE Rotterdam, Netherlands
| | - Douglas Yee
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Reuben S. Harris
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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202
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Greenwood EJD, Matheson NJ, Wals K, van den Boomen DJH, Antrobus R, Williamson JC, Lehner PJ. Temporal proteomic analysis of HIV infection reveals remodelling of the host phosphoproteome by lentiviral Vif variants. eLife 2016; 5:e18296. [PMID: 27690223 PMCID: PMC5085607 DOI: 10.7554/elife.18296] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/28/2016] [Indexed: 12/20/2022] Open
Abstract
Viruses manipulate host factors to enhance their replication and evade cellular restriction. We used multiplex tandem mass tag (TMT)-based whole cell proteomics to perform a comprehensive time course analysis of >6500 viral and cellular proteins during HIV infection. To enable specific functional predictions, we categorized cellular proteins regulated by HIV according to their patterns of temporal expression. We focussed on proteins depleted with similar kinetics to APOBEC3C, and found the viral accessory protein Vif to be necessary and sufficient for CUL5-dependent proteasomal degradation of all members of the B56 family of regulatory subunits of the key cellular phosphatase PP2A (PPP2R5A-E). Quantitative phosphoproteomic analysis of HIV-infected cells confirmed Vif-dependent hyperphosphorylation of >200 cellular proteins, particularly substrates of the aurora kinases. The ability of Vif to target PPP2R5 subunits is found in primate and non-primate lentiviral lineages, and remodeling of the cellular phosphoproteome is therefore a second ancient and conserved Vif function.
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Affiliation(s)
- Edward JD Greenwood
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Nicholas J Matheson
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kim Wals
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Dick JH van den Boomen
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - James C Williamson
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Paul J Lehner
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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203
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Desimmie BA, Burdick RC, Izumi T, Doi H, Shao W, Alvord WG, Sato K, Koyanagi Y, Jones S, Wilson E, Hill S, Maldarelli F, Hu WS, Pathak VK. APOBEC3 proteins can copackage and comutate HIV-1 genomes. Nucleic Acids Res 2016; 44:7848-65. [PMID: 27439715 PMCID: PMC5027510 DOI: 10.1093/nar/gkw653] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 01/31/2023] Open
Abstract
Although APOBEC3 cytidine deaminases A3G, A3F, A3D and A3H are packaged into virions and inhibit viral replication by inducing G-to-A hypermutation, it is not known whether they are copackaged and whether they can act additively or synergistically to inhibit HIV-1 replication. Here, we showed that APOBEC3 proteins can be copackaged by visualization of fluorescently-tagged APOBEC3 proteins using single-virion fluorescence microscopy. We further determined that viruses produced in the presence of A3G + A3F and A3G + A3H, exhibited extensive comutation of viral cDNA, as determined by the frequency of G-to-A mutations in the proviral genomes in the contexts of A3G (GG-to-AG) and A3D, A3F or A3H (GA-to-AA) edited sites. The copackaging of A3G + A3F and A3G + A3H resulted in an additive increase and a modest synergistic increase (1.8-fold) in the frequency of GA-to-AA mutations, respectively. We also identified distinct editing site trinucleotide sequence contexts for each APOBEC3 protein and used them to show that hypermutation of proviral DNAs from seven patients was induced by A3G, A3F (or A3H), A3D and A3G + A3F (or A3H). These results indicate that APOBEC3 proteins can be copackaged and can comutate the same genomes, and can cooperate to inhibit HIV replication.
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Affiliation(s)
- Belete A Desimmie
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Ryan C Burdick
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Taisuke Izumi
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Hibiki Doi
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Wei Shao
- Clinical Retrovirology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - W Gregory Alvord
- Statistical Consulting, Data Management Services, Inc., Frederick, MD 21702, USA
| | - Kei Sato
- Institute of Virus Research, Kyoto University, Kyoto, 606-8057, Japan CREST, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Yoshio Koyanagi
- Institute of Virus Research, Kyoto University, Kyoto, 606-8057, Japan
| | - Sara Jones
- Leidos Biomedical Research, Inc., Bethesda, MD 20892, USA
| | - Eleanor Wilson
- Clinical Retrovirology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Shawn Hill
- Clinical Retrovirology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Frank Maldarelli
- Clinical Retrovirology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Vinay K Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
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204
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Gu J, Chen Q, Xiao X, Ito F, Wolfe A, Chen XS. Biochemical Characterization of APOBEC3H Variants: Implications for Their HIV-1 Restriction Activity and mC Modification. J Mol Biol 2016; 428:4626-4638. [PMID: 27534815 DOI: 10.1016/j.jmb.2016.08.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 08/07/2016] [Accepted: 08/08/2016] [Indexed: 12/26/2022]
Abstract
APOBEC3H (A3H) is the most polymorphic member of the APOBEC3 family. Seven haplotypes (hap I-VII) and four mRNA splicing variants (SV) of A3H have been identified. The various haplotypes differ in anti-HIV activity, which is attributed to differences in protein stability, subcellular distribution, and/or RNA binding and virion packaging. Here, we report the first comparative biochemical studies of all the A3H variants using highly purified proteins. We show that all haplotypes were stably expressed and could be purified to homogeneity by Escherichia coli expression. Surprisingly, four out of the seven haplotypes showed high cytosine (C) deaminase activity, with hap V displaying extremely high activity that was comparable to the highly active A3A. Furthermore, all four haplotypes that were active in C deamination were also highly active on methylated C (mC), with hap II displaying almost equal deamination efficiency on both. The deamination activity of these A3H variants correlates well with their reported anti-HIV activity for the different haplotypes, suggesting that deaminase activity may be an important factor in determining their respective anti-HIV activities. Moreover, mC deamination of A3H displayed a strong preference for the sequence motif of T-mCpG-C/G, which may suggest a potential role in genomic mC modification at the characteristic "CpG" island motif.
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Affiliation(s)
- Jiang Gu
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Qihan Chen
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiao Xiao
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA; Genetic, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Fumiaki Ito
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Aaron Wolfe
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA; Genetic, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology Program, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089, USA; Center of Excellence in NanoBiophysics, University of Southern California, Los Angeles, CA 90089, USA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA; Genetic, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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205
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Mohammed I, Kummetha IR, Singh G, Sharova N, Lichinchi G, Dang J, Stevenson M, Rana TM. 1,2,3-Triazoles as Amide Bioisosteres: Discovery of a New Class of Potent HIV-1 Vif Antagonists. J Med Chem 2016; 59:7677-82. [PMID: 27509004 DOI: 10.1021/acs.jmedchem.6b00247] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RN-18 based viral infectivity factor (Vif), Vif antagonists reduce viral infectivity by rescuing APOBEC3G (A3G) expression and enhancing A3G-dependent Vif degradation. Replacement of amide functionality in RN-18 (IC50 = 6 μM) by isosteric heterocycles resulted in the discovery of a 1,2,3-trizole, 1d (IC50 = 1.2 μM). We identified several potent HIV-1 inhibitors from a 1d based library including 5ax (IC50 = 0.01 μM), 5bx (0.2 μM), 2ey (0.4 μM), 5ey (0.6 μM), and 6bx (0.2 μM).
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Affiliation(s)
- Idrees Mohammed
- Program for RNA Biology, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States
| | - Indrasena Reddy Kummetha
- Department of Pediatrics, University of California San Diego School of Medicine , 9500 Gilman Drive, MC 0762, La Jolla, California 92093 United States
| | - Gatikrushna Singh
- Program for RNA Biology, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States
| | - Natalia Sharova
- Division of Infectious Diseases, Miller School of Medicine, University of Miami , Miami, Florida 33136, United States
| | - Gianluigi Lichinchi
- Program for RNA Biology, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.,Department of Pediatrics, University of California San Diego School of Medicine , 9500 Gilman Drive, MC 0762, La Jolla, California 92093 United States
| | - Jason Dang
- Department of Pediatrics, University of California San Diego School of Medicine , 9500 Gilman Drive, MC 0762, La Jolla, California 92093 United States
| | - Mario Stevenson
- Division of Infectious Diseases, Miller School of Medicine, University of Miami , Miami, Florida 33136, United States
| | - Tariq M Rana
- Program for RNA Biology, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.,Department of Pediatrics, University of California San Diego School of Medicine , 9500 Gilman Drive, MC 0762, La Jolla, California 92093 United States
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206
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Sakai Y, Miyake A, Doi N, Sasada H, Miyazaki Y, Adachi A, Nomaguchi M. Expression Profiles of Vpx/Vpr Proteins Are Co-related with the Primate Lentiviral Lineage. Front Microbiol 2016; 7:1211. [PMID: 27536295 PMCID: PMC4971069 DOI: 10.3389/fmicb.2016.01211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/20/2016] [Indexed: 01/03/2023] Open
Abstract
Viruses of human immunodeficiency virus type 2 (HIV-2) and some simian immunodeficiency virus (SIV) lineages carry a unique accessory protein called Vpx. Vpx is essential or critical for viral replication in natural target cells such as macrophages and T lymphocytes. We have previously shown that a poly-proline motif (PPM) located at the C-terminal region of Vpx is required for its efficient expression in two strains of HIV-2 and SIVmac, and that the Vpx expression levels of the two clones are significantly different. Notably, the PPM sequence is conserved and confined to Vpx and Vpr proteins derived from certain lineages of HIV-2/SIVs. In this study, Vpx/Vpr proteins from diverse primate lentiviral lineages were experimentally and phylogenetically analyzed to obtain the general expression picture in cells. While both the level and PPM-dependency of Vpx/Vpr expression in transfected cells varied among viral strains, each viral group, based on Vpx/Vpr amino acid sequences, was found to exhibit a characteristic expression profile. Moreover, phylogenetic tree analyses on Gag and Vpx/Vpr proteins gave essentially the same results. Taken together, our study described here suggests that each primate lentiviral lineage may have developed a unique expression pattern of Vpx/Vpr proteins for adaptation to its hostile cellular and species environments in the process of viral evolution.
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Affiliation(s)
- Yosuke Sakai
- Department of Microbiology, Tokushima University Graduate School of Medical Science Tokushima, Japan
| | - Ariko Miyake
- Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi University Yamaguchi, Japan
| | - Naoya Doi
- Department of Microbiology, Tokushima University Graduate School of Medical Science Tokushima, Japan
| | - Hikari Sasada
- Department of Microbiology, Tokushima University Graduate School of Medical Science Tokushima, Japan
| | - Yasuyuki Miyazaki
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science Tokyo, Japan
| | - Akio Adachi
- Department of Microbiology, Tokushima University Graduate School of Medical Science Tokushima, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Tokushima University Graduate School of Medical Science Tokushima, Japan
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207
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Abstract
HIV has a very limited species tropism that prevents the use of most conventional small animal models for AIDS research. The in vivo analysis of HIV/AIDS has benefited extensively from novel chimeric animal models that accurately recapitulate key aspects of the human condition. Specifically, immunodeficient mice that are systemically repopulated with human hematolymphoid cells offer a viable alternative for the study of a multitude of highly relevant aspects of HIV replication, pathogenesis, therapy, transmission, prevention, and eradication. This article summarizes some of the multiple contributions that humanized mouse models of HIV infection have made to the field of AIDS research. These models have proven to be highly informative and hold great potential for accelerating multiple aspects of HIV research in the future.
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208
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Functional characterization of Vif proteins from HIV-1 infected patients with different APOBEC3G haplotypes. AIDS 2016; 30:1723-9. [PMID: 27064995 DOI: 10.1097/qad.0000000000001113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The human cytidine deaminase APOBEC3G (A3G) potently restricts HIV-1 but the virus, in turn, expresses a Vif protein which degrades A3G. A natural A3G-H186R variant, common in African populations, has been associated with a more rapid AIDS disease progression, but the underlying mechanism remains unknown. We hypothesized that differences in HIV-1 Vif activity towards A3G wild type and A3G-H186R contribute to the distinct clinical AIDS manifestation. METHODS Vif variants were cloned from plasma samples of 26 South African HIV-1 subtype C infected patients, which either express wild type A3G or A3G-H186R. The Vif alleles were assessed for their ability to counteract A3G variants using western blot and single-cycle infectivity assays. RESULTS We obtained a total of 392 Vif sequences which displayed an amino acid sequence difference of 6.2-19.2% between patients. The intrapatient Vif diversities from patient groups A3G, A3G and A3G were similar. Vif variants obtained from patients expressing A3G and A3G were capable of counteracting both A3G variants with similar efficiency. However, the antiviral activity of A3G-H186R was significantly reduced in both the presence and absence of Vif, indicating that the A3G-H186R variant intrinsically exerts less antiviral activity. CONCLUSION A3G wild type and A3G-H186R are equally susceptible to counteraction by Vif, regardless of whether the Vif variant was obtained from A3G and A3G patients. However, the A3G-H186R variant intrinsically displayed lower antiviral activity, which could explain the higher plasma viral loads and accelerated disease progression reported for patients expressing A3G.
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209
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Crystal structure of the Trim5α Bbox2 domain from rhesus macaques describes a plastic oligomerisation interface. J Struct Biol 2016; 195:282-285. [PMID: 27402535 DOI: 10.1016/j.jsb.2016.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 11/21/2022]
Abstract
Retroviral pathogens have been an evolutionary pressure for many primate species, driving the development of an intrinsic cellular response to retroviruses and antiretroviral proteins. One such antiretroviral protein is the restriction factor Trim5α, that blocks HIV-1 infection in rhesus macaques at an early post-entry stage in the retroviral lifecycle. Trim5α self-assembles into a large hexagonal array, complimentary to the retroviral capsid. Assembly is mediated by the conserved N-terminal architecture comprising a RING domain, a Bbox domain, and a coiled coil. Recently we have shown that the Bbox domain and elements of the coiled coil form a trimer in solution, and that the Bbox domain drives assembly. During crystallisation experiments using the trimer forming construct, we determined the structure of a dimeric Bbox domain to a resolution of 1.8Å. Interface analysis reveals that residues previously shown to be required for assembly and restriction, Glu120 and Arg121, are central to the interface. Comparison to a mutant Trim5α dimer interface shows a translation of the Bbox dimerisation interface removing interactions important in the wildtype protein.
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210
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Crespo H, Bertolotti L, Proffiti M, Cascio P, Cerruti F, Acutis PL, de Andrés D, Reina R, Rosati S. Low proviral small ruminant lentivirus load as biomarker of natural restriction in goats. Vet Microbiol 2016; 192:152-162. [PMID: 27527777 DOI: 10.1016/j.vetmic.2016.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 11/16/2022]
Abstract
Small ruminant lentiviruses (SRLV) globally affect welfare and production of sheep and goats and are mainly controlled through elimination of infected animals, independently of the viral kinetics within the single animal. Control programs are based on highly sensitive serological tests, however the existence of low antibody responders leads to the permanent presence of seronegative infected animals in the flock, thus perpetuating the infection. On the other hand, long-term non-progressors show a detectable antibody response not indicative of a shedding animal, suggesting immune contention of infection. In this study, we analyse two goat populations within the same herd, harbouring low or high proviral SRLV loads respectively, both showing a robust antibody response. In vivo findings were confirmed in vitro since fibroblastic cell lines obtained from one high and one low proviral load representative goats, showed respectively a high and a faint production of virus upon infection with reference and field circulating SRLV strains. Differences in virus production were relieved when strain CAEV-Co was used for experimental infection. We analysed LTR promoter activity, proviral load, entry step and production of virus and viral proteins. Intriguingly, proteasomal activity was higher in fibroblasts from low proviral load animals and proteasome inhibition increased viral production in both cell lines, suggesting the implication of active proteasome-dependent restriction factors. Among them, we analysed relative expression and sequences of TRIM5α, APOBEC3 (Z1, Z2, Z3 and Z2-Z3) and BST-2 (Tetherin) and found a global antiviral status in low proviral carriers that may confer protection against viral shedding and disease onset.
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Affiliation(s)
- Helena Crespo
- Instituto de Agrobiotecnología, UPNA-CSIC-Gob, de Navarra, Avda. Pamplona 123, 31192 Mutilva, Spain
| | - Luigi Bertolotti
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, L.go P. Braccini 2, 10095 Grugliasco (TO), Italy
| | - Margherita Proffiti
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, L.go P. Braccini 2, 10095 Grugliasco (TO), Italy
| | - Paolo Cascio
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, L.go P. Braccini 2, 10095 Grugliasco (TO), Italy
| | - Fulvia Cerruti
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, L.go P. Braccini 2, 10095 Grugliasco (TO), Italy
| | - Pier Luigi Acutis
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
| | - Damián de Andrés
- Instituto de Agrobiotecnología, UPNA-CSIC-Gob, de Navarra, Avda. Pamplona 123, 31192 Mutilva, Spain
| | - Ramsés Reina
- Instituto de Agrobiotecnología, UPNA-CSIC-Gob, de Navarra, Avda. Pamplona 123, 31192 Mutilva, Spain.
| | - Sergio Rosati
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, L.go P. Braccini 2, 10095 Grugliasco (TO), Italy
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Boyd DF, Sharma A, Humes D, Cheng-Mayer C, Overbaugh J. Adapting SHIVs In Vivo Selects for Envelope-Mediated Interferon-α Resistance. PLoS Pathog 2016; 12:e1005727. [PMID: 27399306 PMCID: PMC4939950 DOI: 10.1371/journal.ppat.1005727] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/05/2016] [Indexed: 02/07/2023] Open
Abstract
Lentiviruses are able to establish persistent infection in their respective hosts despite a potent type-I interferon (IFN-I) response following transmission. A number of IFN-I-induced host factors that are able to inhibit lentiviral replication in vitro have been identified, and these studies suggest a role for IFN-induced factors as barriers to cross-species transmission. However, the ability of these factors to inhibit viral replication in vivo has not been well characterized, nor have the viral determinants that contribute to evasion or antagonism of the host IFN-I response. In this study, we hypothesized that the host IFN-I response serves as a strong selective pressure in the context of SIV/HIV chimeric virus (SHIV) infection of macaques and sought to identify the viral determinants that contribute to IFN-I resistance. We assessed the ability of SHIVs encoding HIV-1 sequences adapted by serial passage in macaques versus SHIVs encoding HIV sequences isolated directly from infected individuals to replicate in the presence of IFNα in macaque lymphocytes. We demonstrate that passage in macaques selects for IFNα resistant viruses that have higher replication kinetics and increased envelope content. SHIVs that encode HIV-1 sequences derived directly from infected humans were sensitive to IFNα -induced inhibition whereas SHIVs obtained after passage in macaques were not. This evolutionary process was directly observed in viruses that were serially passaged during the first few months of infection-a time when the IFNα response is high. Differences in IFNα sensitivity mapped to HIV-1 envelope and were associated with increased envelope levels despite similar mRNA expression, suggesting a post-transcriptional mechanism. These studies highlight critical differences in IFNα sensitivity between HIV-1 sequences in infected people and those used in SHIV models.
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Affiliation(s)
- David F. Boyd
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Pathobiology Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Amit Sharma
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Daryl Humes
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | | | - Julie Overbaugh
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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212
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Rotavirus NSP1 Associates with Components of the Cullin RING Ligase Family of E3 Ubiquitin Ligases. J Virol 2016; 90:6036-48. [PMID: 27099313 DOI: 10.1128/jvi.00704-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The rotavirus nonstructural protein NSP1 acts as an antagonist of the host antiviral response by inducing degradation of key proteins required to activate interferon (IFN) production. Protein degradation induced by NSP1 is dependent on the proteasome, and the presence of a RING domain near the N terminus has led to the hypothesis that NSP1 is an E3 ubiquitin ligase. To examine this hypothesis, pulldown assays were performed, followed by mass spectrometry to identify components of the host ubiquitination machinery that associate with NSP1. Multiple components of cullin RING ligases (CRLs), which are essential multisubunit ubiquitination complexes, were identified in association with NSP1. The mass spectrometry was validated in both transfected and infected cells to show that the NSP1 proteins from different strains of rotavirus associated with key components of CRL complexes, most notably the cullin scaffolding proteins Cul3 and Cul1. In vitro binding assays using purified proteins confirmed that NSP1 specifically interacted with Cul3 and that the N-terminal region of Cul3 was responsible for binding to NSP1. To test if NSP1 used CRL3 to induce degradation of the target protein IRF3 or β-TrCP, Cul3 levels were knocked down using a small interfering RNA (siRNA) approach. Unexpectedly, loss of Cul3 did not rescue IRF3 or β-TrCP from degradation in infected cells. The results indicate that, rather than actively using CRL complexes to induce degradation of target proteins required for IFN production, NSP1 may use cullin-containing complexes to prevent another cellular activity. IMPORTANCE The ubiquitin-proteasome pathway plays an important regulatory role in numerous cellular functions, and many viruses have evolved mechanisms to exploit or manipulate this pathway to enhance replication and spread. Rotavirus, a major cause of severe gastroenteritis in young children that causes approximately 420,000 deaths worldwide each year, utilizes the ubiquitin-proteasome system to subvert the host innate immune response by inducing the degradation of key components required for the production of interferon (IFN). Here, we show that NSP1 proteins from different rotavirus strains associate with the scaffolding proteins Cul1 and Cul3 of CRL ubiquitin ligase complexes. Nonetheless, knockdown of Cul1 and Cul3 suggests that NSP1 induces the degradation of some target proteins independently of its association with CRL complexes, stressing a need to further investigate the mechanistic details of how NSP1 subverts the host IFN response.
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213
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Hotter D, Sauter D, Kirchhoff F. Guanylate binding protein 5: Impairing virion infectivity by targeting retroviral envelope glycoproteins. Small GTPases 2016; 8:31-37. [PMID: 27275775 PMCID: PMC5331900 DOI: 10.1080/21541248.2016.1189990] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Guanylate binding proteins (GBPs) are interferon-inducible cellular factors that belong to the superfamily of guanosine triphosphatases (GTPases) and play important roles in the cell-intrinsic defense against bacteria, protozoa and viruses. In a recent report in Cell Host & Microbe, we identify GBP5 as novel restriction factor of HIV-1 that reduces the infectivity of progeny virions by interfering with processing and incorporation of the viral envelope (Env) glycoprotein. The inhibitory activity of GBP5 requires C-terminal isoprenylation, mediating Golgi-association, but not its GTPase function. Notably, GBP5 expression levels vary considerably in human macrophages and inversely correlate with infectious virus yield. We demonstrate that GBP5 can be evaded by an unusual tradeoff mechanism: Naturally occurring mutations in the start codon of the viral accessory gene vpu attenuate GBP5 inhibition by increasing Env expression at the cost of Vpu function. Whether direct counteraction mechanisms or more subtle changes balancing Vpu and Env expression also affect HIV-1 inhibition by GBP5 remains to be clarified. Other open questions are whether GBP5 restricts HIV-1 in CD4+ T cells and if other GBP family members also decrease infectivity of HIV and/or additional enveloped viruses.
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Affiliation(s)
- Dominik Hotter
- a Institute of Molecular Virology, Ulm University Medical Center , Ulm , Germany
| | - Daniel Sauter
- a Institute of Molecular Virology, Ulm University Medical Center , Ulm , Germany
| | - Frank Kirchhoff
- a Institute of Molecular Virology, Ulm University Medical Center , Ulm , Germany
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214
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Wilkins J, Zheng YM, Yu J, Liang C, Liu SL. Nonhuman Primate IFITM Proteins Are Potent Inhibitors of HIV and SIV. PLoS One 2016; 11:e0156739. [PMID: 27257969 PMCID: PMC4892622 DOI: 10.1371/journal.pone.0156739] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/18/2016] [Indexed: 12/15/2022] Open
Abstract
Interferon-induced transmembrane (IFITM) proteins are potent antiviral factors shown to restrict the infection of many enveloped viruses, including HIV. Here we report cloning and characterization of a panel of nonhuman primate IFITMs. We show that, similar to human IFITM, nonhuman primate IFITM proteins inhibit HIV and other primate lentiviruses. While some nonhuman primate IFITM proteins are more potent than human counterparts to inhibit HIV-1, they are generally not effective against HIV-2 similar to that of human IFITMs. Notably, depending on SIV strains and also IFITM species tested, nonhuman primate IFITM proteins exhibit distinct activities against SIVs; no correlation was found to support the notion that IFITM proteins are most active in non-natural primate hosts. Consistent with our recent findings for human IFITMs, nonhuman primate IFITM proteins interact with HIV-1 Env and strongly act in viral producer cells to impair viral infectivity and block cell-to-cell transmission. Accordingly, knockdown of primate IFITM3 increases HIV-1 replication in nohuman primate cells. Interestingly, analysis of DNA sequences of human and nonhuman primate IFITMs suggest that IFITM proteins have been undergoing purifying selection, rather than positive selection typical for cellular restriction factors. Overall, our study reveals some new and unexpected features of IFITMs in restricting primate lentiviruses, which enhances our understanding of virus-host interaction and AIDS pathogenesis.
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Affiliation(s)
- Jordan Wilkins
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Yi-Min Zheng
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Jingyou Yu
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Chen Liang
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Departments of Medicine, Microbiology & Immunology, McGill University, Montreal, Quebec, Canada
| | - Shan-Lu Liu
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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215
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Roles of Capsid-Interacting Host Factors in Multimodal Inhibition of HIV-1 by PF74. J Virol 2016; 90:5808-5823. [PMID: 27076642 DOI: 10.1128/jvi.03116-15] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 04/02/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The viral capsid of HIV-1 interacts with a number of host factors to orchestrate uncoating and regulate downstream events, such as reverse transcription, nuclear entry, and integration site targeting. PF-3450074 (PF74), an HIV-1 capsid-targeting low-molecular-weight antiviral compound, directly binds to the capsid (CA) protein at a site also utilized by host cell proteins CPSF6 and NUP153. Here, we found that the dose-response curve of PF74 is triphasic, consisting of a plateau and two inhibitory phases of different slope values, consistent with a bimodal mechanism of drug action. High PF74 concentrations yielded a steep curve with the highest slope value among different classes of known antiretrovirals, suggesting a dose-dependent, cooperative mechanism of action. CA interactions with both CPSF6 and cyclophilin A (CypA) were essential for the unique dose-response curve. A shift of the steep curve at lower drug concentrations upon blocking the CA-CypA interaction suggests a protective role for CypA against high concentrations of PF74. These findings, highlighting the unique characteristics of PF74, provide a model in which its multimodal mechanism of action of both noncooperative and cooperative inhibition by PF74 is regulated by interactions of cellular proteins with incoming viral capsids. IMPORTANCE PF74, a novel capsid-targeting antiviral against HIV-1, shares its binding site in the viral capsid protein (CA) with the host factors CPSF6 and NUP153. This work reveals that the dose-response curve of PF74 consists of two distinct inhibitory phases that are differentially regulated by CA-interacting host proteins. PF74's potency depended on these CA-binding factors at low doses. In contrast, the antiviral activity of high PF74 concentrations was attenuated by cyclophilin A. These observations provide novel insights into both the mechanism of action of PF74 and the roles of host factors during the early steps of HIV-1 infection.
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216
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Wei W, Guo H, Ma M, Markham R, Yu XF. Accumulation of MxB/Mx2-resistant HIV-1 Capsid Variants During Expansion of the HIV-1 Epidemic in Human Populations. EBioMedicine 2016; 8:230-236. [PMID: 27428433 PMCID: PMC4919602 DOI: 10.1016/j.ebiom.2016.04.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 11/06/2022] Open
Abstract
Recent studies have identified human myxovirus resistance protein 2 (MxB or Mx2) as an interferon induced inhibitor of HIV-1 replication. However, whether HIV-1 can overcome MxB restriction without compromise of viral fitness has been undefined. Here, we have discovered that naturally occurring capsid (CA) variants can render HIV-1 resistant to the activity of MxB without losing viral infectivity or the ability to escape from interferon induction. Moreover, these MxB resistant HIV-1 variants do not lose MxB recognition. Surprisingly, MxB resistant CA variants are most commonly found in the Clade C HIV-1 that is the most rapidly expanding Clade throughout the world. Accumulation of MxB resistant mutations is also observed during HIV-1 spreading in human populations. These findings support a potential role for MxB as a selective force during HIV-1 transmission and evolution. Naturally occurring HIV-1capsid variants confer HIV-1 resistance to MxB. MxB-resistant capsid A116 is a major variant in HIV-1 Subtype C. HIV-1 capsid variant A116 is accumulating during expansion of the HIV-1 epidemic in China. MxB-resistant HIV-1 capsid variants maintain interaction with MxB.
Interferon (IFN) is a key component of the innate immune response to exogenous pathogens. Human MxB has been identified as a potent inhibitor of HIV-1 induced by interferon. How HIV-1 escapes from MxB inhibition is not clear. This study demonstrates that capsid variations detected in primary HIV-1 isolates can mediate MxB resistance. MxB resistant capsid mutations can accumulate during HIV-1 transmission and are mostly enriched in Clade C HIV-1 that is the most rapidly expanding Clade throughout the world. Identification of the critical role of these capsid mutations in overcoming a host restriction factor may provide opportunities for the development of therapeutic interventions.
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Affiliation(s)
- Wei Wei
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin Province, China; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
| | - Haoran Guo
- School of Life Sciences, Tianjin University, Tianjin, China
| | - Min Ma
- School of Life Sciences, Tianjin University, Tianjin, China
| | - Richard Markham
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Xiao-Fang Yu
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin Province, China; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
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217
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Lahaye X, Satoh T, Gentili M, Cerboni S, Silvin A, Conrad C, Ahmed-Belkacem A, Rodriguez EC, Guichou JF, Bosquet N, Piel M, Le Grand R, King MC, Pawlotsky JM, Manel N. Nuclear Envelope Protein SUN2 Promotes Cyclophilin-A-Dependent Steps of HIV Replication. Cell Rep 2016; 15:879-892. [PMID: 27149839 PMCID: PMC4850421 DOI: 10.1016/j.celrep.2016.03.074] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 02/12/2016] [Accepted: 03/20/2016] [Indexed: 12/01/2022] Open
Abstract
During the early phase of replication, HIV reverse transcribes its RNA and crosses the nuclear envelope while escaping host antiviral defenses. The host factor Cyclophilin A (CypA) is essential for these steps and binds the HIV capsid; however, the mechanism underlying this effect remains elusive. Here, we identify related capsid mutants in HIV-1, HIV-2, and SIVmac that are restricted by CypA. This antiviral restriction of mutated viruses is conserved across species and prevents nuclear import of the viral cDNA. Importantly, the inner nuclear envelope protein SUN2 is required for the antiviral activity of CypA. We show that wild-type HIV exploits SUN2 in primary CD4+ T cells as an essential host factor that is required for the positive effects of CypA on reverse transcription and infection. Altogether, these results establish essential CypA-dependent functions of SUN2 in HIV infection at the nuclear envelope. HIV capsid mutants reveal that Cyclophilin A can restrict viral nuclear import Nuclear envelope protein SUN2 is implicated in the restriction of HIV mutants SUN2 is essential for wild-type HIV infection in CD4+ T cells and dendritic cells In CD4+ T cells, the activities of CypA on HIV-1 infection require SUN2
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Affiliation(s)
- Xavier Lahaye
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Takeshi Satoh
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Matteo Gentili
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Silvia Cerboni
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Aymeric Silvin
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Cécile Conrad
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | | | - Elisa C Rodriguez
- Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520-8002, USA
| | - Jean-François Guichou
- CNRS UMR5048, INSERM U1054 - Université de Montpellier, Centre de Biochimie Structurale, 34090 Montpellier, France
| | - Nathalie Bosquet
- Université Paris Sud, INSERM, CEA, DRF-Immunology of Viral Infections and Autoimmune Diseases department (IMVA), UMR1184, IDMIT Infrastructure, iMETI, 92260 Fontenay-aux-Roses, France
| | - Matthieu Piel
- Subcellular Structure and Cellular Dynamics Department, Institut Curie, PSL Research University, CNRS UMR144, 75005 Paris, France; Institut Pierre-Gilles de Gennes, PSL Research University, 75005 Paris, France
| | - Roger Le Grand
- Université Paris Sud, INSERM, CEA, DRF-Immunology of Viral Infections and Autoimmune Diseases department (IMVA), UMR1184, IDMIT Infrastructure, iMETI, 92260 Fontenay-aux-Roses, France
| | - Megan C King
- Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520-8002, USA
| | - Jean-Michel Pawlotsky
- INSERM U955, 94010 Créteil, France; Department of Virology, National Reference Center for Viral Hepatitis B, C and D, Hôpital Henri Mondor, Université Paris-Est, 94010 Créteil, France
| | - Nicolas Manel
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France.
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Natural Single-Nucleotide Variations in the HIV-1 Genomic SA1prox Region Can Alter Viral Replication Ability by Regulating Vif Expression Levels. J Virol 2016; 90:4563-4578. [PMID: 26912631 DOI: 10.1128/jvi.02939-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/15/2016] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED We previously found that natural single-nucleotide variations located within a proximal region of splicing acceptor 1 (SA1prox) in the HIV-1 genome could alter the viral replication potential and mRNA expression pattern, especially the vif mRNA level. Here, we studied the virological and molecular basis of nucleotide sequence variations in SA1prox for alterations of viral replication ability. Consistent with our previous findings, variant clones indeed expressed Vif at different levels and grew distinctively in cells with various APOBEC3G expression levels. Similar effects were observed for natural variations found in HIV-2 SA1prox, suggesting the importance of the SA1prox sequence. To define nucleotides critical for the regulation of HIV-1 Vif expression, effects of natural SA1prox variations newly found in the HIV Sequence Compendium database on vif mRNA/Vif protein levels were examined. Seven out of nine variations were found to produce Vif at lower, higher, or more excessive levels than wild-type NL4-3. Combination experiments of variations giving distinct Vif levels suggested that the variations mutually affected vif transcript production. While low and high producers of Vif grew in an APOBEC3G-dependent manner, excessive expressers always showed an impeded growth phenotype due to defects in single-cycle infectivity and/or virion production levels. The phenotype of excessive expressers was not due primarily to inadequate expression of Tat or Rev, although SA1prox variations altered the overall HIV-1 mRNA expression pattern. Collectively, our results demonstrate that HIV SA1prox regulates Vif expression levels and suggest a relationship between SA1prox and viral adaptation/evolution given that variations occurred naturally. IMPORTANCE While human cells possess restriction factors to inhibit HIV-1 replication, HIV-1 encodes antagonists to overcome these barriers. Conflicts between host restriction factors and viral counterparts are critical driving forces behind mutual evolution. The interplay of cellular APOBEC3G and viral Vif proteins is a typical example. Here, we demonstrate that naturally occurring single-nucleotide variations in the proximal region of splicing acceptor 1 (SA1prox) of the HIV-1 genome frequently alter Vif expression levels, thereby modulating viral replication potential in cells with various ABOBEC3G levels. The results of the present study reveal a previously unidentified and important way for HIV-1 to compete with APOBEC3G restriction by regulating its Vif expression levels. We propose that SA1prox plays a regulatory role in Vif counteraction against APOBEC3G in order to contribute to HIV-1 replication and evolution, and this may be applicable to other primate lentiviruses.
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219
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The clinical applications of genome editing in HIV. Blood 2016; 127:2546-52. [PMID: 27053530 DOI: 10.1182/blood-2016-01-678144] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/09/2016] [Indexed: 12/13/2022] Open
Abstract
HIV/AIDS has long been at the forefront of the development of gene- and cell-based therapies. Although conventional gene therapy approaches typically involve the addition of anti-HIV genes to cells using semirandomly integrating viral vectors, newer genome editing technologies based on engineered nucleases are now allowing more precise genetic manipulations. The possible outcomes of genome editing include gene disruption, which has been most notably applied to the CCR5 coreceptor gene, or the introduction of small mutations or larger whole gene cassette insertions at a targeted locus. Disruption of CCR5 using zinc finger nucleases was the first-in-human application of genome editing and remains the most clinically advanced platform, with 7 completed or ongoing clinical trials in T cells and hematopoietic stem/progenitor cells (HSPCs). Here we review the laboratory and clinical findings of CCR5 editing in T cells and HSPCs for HIV therapy and summarize other promising genome editing approaches for future clinical development. In particular, recent advances in the delivery of genome editing reagents and the demonstration of highly efficient homology-directed editing in both T cells and HSPCs are expected to spur the development of even more sophisticated applications of this technology for HIV therapy.
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220
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Abstract
Long terminal repeat (LTR) retrotransposons constitute significant fractions of many eukaryotic genomes. Two ancient families are Ty1/Copia (Pseudoviridae) and Ty3/Gypsy (Metaviridae). The Ty3/Gypsy family probably gave rise to retroviruses based on the domain order, similarity of sequences, and the envelopes encoded by some members. The Ty3 element of Saccharomyces cerevisiae is one of the most completely characterized elements at the molecular level. Ty3 is induced in mating cells by pheromone stimulation of the mitogen-activated protein kinase pathway as cells accumulate in G1. The two Ty3 open reading frames are translated into Gag3 and Gag3-Pol3 polyprotein precursors. In haploid mating cells Gag3 and Gag3-Pol3 are assembled together with Ty3 genomic RNA into immature virus-like particles in cellular foci containing RNA processing body proteins. Virus-like particle Gag3 is then processed by Ty3 protease into capsid, spacer, and nucleocapsid, and Gag3-Pol3 into those proteins and additionally, protease, reverse transcriptase, and integrase. After haploid cells mate and become diploid, genomic RNA is reverse transcribed into cDNA. Ty3 integration complexes interact with components of the RNA polymerase III transcription complex resulting in Ty3 integration precisely at the transcription start site. Ty3 activation during mating enables proliferation of Ty3 between genomes and has intriguing parallels with metazoan retrotransposon activation in germ cell lineages. Identification of nuclear pore, DNA replication, transcription, and repair host factors that affect retrotransposition has provided insights into how hosts and retrotransposons interact to balance genome stability and plasticity.
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Abstract
Over 40% of mammalian genomes comprise the products of reverse transcription. Among such retrotransposed sequences are those characterized by the presence of long terminal repeats (LTRs), including the endogenous retroviruses (ERVs), which are inherited genetic elements closely resembling the proviruses formed following exogenous retrovirus infection. Sequences derived from ERVs make up at least 8 to 10% of the human and mouse genomes and range from ancient sequences that predate mammalian divergence to elements that are currently still active. In this chapter we describe the discovery, classification and origins of ERVs in mammals and consider cellular mechanisms that have evolved to control their expression. We also discuss the negative effects of ERVs as agents of genetic disease and cancer and review examples of ERV protein domestication to serve host functions, as in placental development. Finally, we address growing evidence that the gene regulatory potential of ERV LTRs has been exploited multiple times during evolution to regulate genes and gene networks. Thus, although recently endogenized retroviral elements are often pathogenic, those that survive the forces of negative selection become neutral components of the host genome or can be harnessed to serve beneficial roles.
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222
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Thompson J, Ma F, Quinn M, Xiang SH. Genome-Wide Search for Host Association Factors during Ovine Progressive Pneumonia Virus Infection. PLoS One 2016; 11:e0150344. [PMID: 26950733 PMCID: PMC4780736 DOI: 10.1371/journal.pone.0150344] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/14/2016] [Indexed: 11/18/2022] Open
Abstract
Ovine progressive pneumonia virus (OPPV) is an important virus that causes serious diseases in sheep and goats with a prevalence of 36% in the USA. Although OPPV was discovered more than half of a century ago, little is known about the infection and pathogenesis of this virus. In this report, we used RNA-seq technology to conduct a genome-wide probe for cellular factors that are associated with OPPV infection. A total of approximately 22,000 goat host genes were detected of which 657 were found to have been significantly up-regulated and 889 down-regulated at 12 hours post-infection. In addition to previously known restriction factors from other viral infections, a number of factors which may be specific for OPPV infection were uncovered. The data from this RNA-seq study will be helpful in our understanding of OPPV infection, and also for further study in the prevention and intervention of this viral disease.
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Affiliation(s)
- Jesse Thompson
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- School of Veterinary Medicine and Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Fangrui Ma
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Meghan Quinn
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- School of Veterinary Medicine and Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Shi-Hua Xiang
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- School of Veterinary Medicine and Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- * E-mail:
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223
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SAMHD1 transcript upregulation during SIV infection of the central nervous system does not associate with reduced viral load. Sci Rep 2016; 6:22629. [PMID: 26936683 PMCID: PMC4776177 DOI: 10.1038/srep22629] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/18/2016] [Indexed: 02/01/2023] Open
Abstract
Restriction of HIV-1 in myeloid-lineage cells is attributed in part to the nucleotidase activity of the SAM-domain and HD-domain containing protein (SAMHD1), which depletes free nucleotides, blocking reverse transcription. In the same cells, the Vpx protein of HIV-2 and most SIVs counteracts SAMHD1. Both Type I and II interferons may stimulate SAMHD1 transcription. The contributions of SAMHD1 to retroviral restriction in the central nervous system (CNS) have been the subject of limited study. We hypothesized that SAMHD1 would respond to interferon in the SIV-infected CNS but would not control virus due to SIV Vpx. Accordingly, we investigated SAMHD1 transcript abundance and association with the Type I interferon response in an SIV model. SAMHD1 transcript levels were IFN responsive, increasing during acute phase infection and decreasing during a more quiescent phase, but generally remaining elevated at all post-infection time points. In vitro, SAMHD1 transcript was abundant in macaque astrocytes and further induced by Type I interferon, while IFN produced a weaker response in the more permissive environment of the macrophage. We cannot rule out a contribution of SAMHD1 to retroviral restriction in relatively non-permissive CNS cell types. We encourage additional research in this area, particularly in the context of HIV-1 infection.
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Abstract
A fascinating aspect of retroviruses is their tendency to nonrandomly incorporate host cell RNAs into virions. In addition to the specific tRNAs that prime reverse transcription, all examined retroviruses selectively package multiple host cell noncoding RNAs (ncRNAs). Many of these ncRNAs appear to be encapsidated shortly after synthesis, before assembling with their normal protein partners. Remarkably, although some packaged ncRNAs, such as pre-tRNAs and the spliceosomal U6 small nuclear RNA (snRNA), were believed to reside exclusively within mammalian nuclei, it was demonstrated recently that the model retrovirus murine leukemia virus (MLV) packages these ncRNAs from a novel pathway in which unneeded nascent ncRNAs are exported to the cytoplasm for degradation. The finding that retroviruses package forms of ncRNAs that are rare in cells suggests several hypotheses for how these RNAs could assist retrovirus assembly and infectivity. Moreover, recent experiments in several laboratories have identified additional ways in which cellular ncRNAs may contribute to the retrovirus life cycle. This review focuses on the ncRNAs that are packaged by retroviruses and the ways in which both encapsidated ncRNAs and other cellular ncRNAs may contribute to retrovirus replication.
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Abstract
HIV persistence in patients undergoing antiretroviral therapy is a major impediment to the cure of HIV/AIDS. The molecular and cellular mechanisms underlying HIV persistence in vivo have not been fully elucidated. This lack of basic knowledge has hindered progress in this area. The in vivo analysis of HIV persistence and the implementation of curative strategies would benefit from animal models that accurately recapitulate key aspects of the human condition. This Review summarizes the contribution that humanized mouse models of HIV infection have made to the field of HIV cure research. Even though these models have been shown to be highly informative in many specific areas, their great potential to serve as excellent platforms for discovery in HIV pathogenesis and treatment has yet to be fully developed.
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226
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Dotson D, Woodruff EA, Villalta F, Dong X. Filamin A Is Involved in HIV-1 Vpu-mediated Evasion of Host Restriction by Modulating Tetherin Expression. J Biol Chem 2016; 291:4236-46. [PMID: 26742839 DOI: 10.1074/jbc.m115.708123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Indexed: 11/06/2022] Open
Abstract
Tetherin, also known as bone marrow stromal antigen 2 (BST-2), inhibits the release of a wide range of enveloped viruses, including human immunodeficiency virus, type 1 (HIV-1) by directly tethering nascent virions to the surface of infected cells. The HIV-1 accessary protein Vpu counteracts tetherin restriction via sequestration, down-regulation, and/or displacement mechanisms to remove tetherin from sites of virus budding. However, the exact mechanism of Vpu-mediated antagonism of tetherin restriction remains to be fully understood. Here we report a novel role for the actin cross-linking regulator filamin A (FLNa) in Vpu anti-tetherin activities. We demonstrate that FLNa associates with tetherin and that FLNa modulates tetherin turnover. FLNa deficiency was found to enhance cell surface and steady-state levels of tetherin expression. In contrast, we observed that overexpression of FLNa reduced tetherin expression levels both on the plasma membrane and in intracellular compartments. Although FLNb shows high amino acid sequence similarity with FLNa, we reveal that only FLNa, but not FLNb, plays an essential role in tetherin turnover. We further showed that FLNa deficiency inhibited Vpu-mediated enhancement of virus release through interfering with the activity of Vpu to down-regulate cellular tetherin. Taken together, our studies suggest that Vpu hijacks the FLNa function in the modulation of tetherin to neutralize the antiviral factor tetherin. These findings may provide novel strategies for the treatment of HIV-1 infection.
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Affiliation(s)
- Dominique Dotson
- From the Department of Microbiology and Immunology and Center for AIDS Health Disparities Research, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208
| | - Elvin A Woodruff
- From the Department of Microbiology and Immunology and Center for AIDS Health Disparities Research, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208
| | - Fernando Villalta
- From the Department of Microbiology and Immunology and Center for AIDS Health Disparities Research, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208
| | - Xinhong Dong
- From the Department of Microbiology and Immunology and Center for AIDS Health Disparities Research, School of Medicine, Meharry Medical College, Nashville, Tennessee 37208
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227
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Specific induction of endogenous viral restriction factors using CRISPR/Cas-derived transcriptional activators. Proc Natl Acad Sci U S A 2015; 112:E7249-56. [PMID: 26668372 DOI: 10.1073/pnas.1516305112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Whereas several mammalian proteins can restrict the replication of HIV-1 and other viruses, these are often not expressed in relevant target cells. A potential method to inhibit viral replication might therefore be to use synthetic transcription factors to induce restriction factor expression. In particular, mutants of the RNA-guided DNA binding protein Cas9 that have lost their DNA cleavage activity could be used to recruit transcription activation domains to specific promoters. However, initial experiments revealed only weak activation unless multiple promoter-specific single guide RNAs (sgRNAs) were used. Recently, the recruitment of multiple transcription activation domains by a single sgRNA, modified to contain MS2-derived stem loops that recruit fusion proteins consisting of the MS2 coat protein linked to transcription activation domains, was reported to induce otherwise silent cellular genes. Here, we demonstrate that such "synergistic activation mediators" can induce the expression of two restriction factors, APOBEC3G (A3G) and APOBEC3B (A3B), in human cells that normally lack these proteins. We observed modest activation of endogenous A3G or A3B expression using single sgRNAs but high expression when two sgRNAs were used. Whereas the induced A3G and A3B proteins both blocked infection by an HIV-1 variant lacking a functional vif gene by inducing extensive dC-to-dU editing, only the induced A3B protein inhibited wild-type HIV-1. These data demonstrate that Cas9-derived transcriptional activators have the potential to be used for screens for endogenous genes that affect virus replication and raise the possibility that synthetic transcription factors might prove clinically useful if efficient delivery mechanisms could be developed.
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Garfinkel DJ, Tucker JM, Saha A, Nishida Y, Pachulska-Wieczorek K, Błaszczyk L, Purzycka KJ. A self-encoded capsid derivative restricts Ty1 retrotransposition in Saccharomyces. Curr Genet 2015; 62:321-9. [PMID: 26650614 DOI: 10.1007/s00294-015-0550-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 11/24/2015] [Indexed: 11/27/2022]
Abstract
Retrotransposons and retroviral insertions have molded the genomes of many eukaryotes. Since retroelements transpose via an RNA intermediate, the additive nature of the replication cycle can result in massive increases in copy number if left unchecked. Host organisms have countered with several defense systems, including domestication of retroelement genes that now act as restriction factors to minimize propagation. We discovered a novel truncated form of the Saccharomyces Ty1 retrotransposon capsid protein, dubbed p22 that inhibits virus-like particle (VLP) assembly and function. The p22 restriction factor expands the repertoire of defense proteins targeting the capsid and highlights a novel host-parasite strategy. Instead of inhibiting all transposition by domesticating the restriction gene as a distinct locus, Ty1 and budding yeast may have coevolved a relationship that allows high levels of transposition when Ty1 copy numbers are low and progressively less transposition as copy numbers rise. Here, we offer a perspective on p22 restriction, including its mode of expression, effect on VLP functions, interactions with its target, properties as a nucleic acid chaperone, similarities to other restriction factors, and future directions.
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Affiliation(s)
- David J Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA.
| | - Jessica M Tucker
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Agniva Saha
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Yuri Nishida
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Katarzyna Pachulska-Wieczorek
- Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Leszek Błaszczyk
- Institute of Computing Science, Poznan University of Technology, Poznan, Poland
| | - Katarzyna J Purzycka
- Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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Bunupuradah T, Matsuoka K, Imahashi M, Iwatani Y, Ananworanich J, Puthanakit T, Saphonn V, Aurpibul L, Sophonphan J, Yagi T, Phanuphak P, Sugiura W. APOBEC3G genotypes and proviral DNA hypermutations on HIV/AIDS disease progression in Thai and Cambodian children. Future Virol 2015. [DOI: 10.2217/fvl.15.101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim: To evaluate the effect of APOBEC3G host factor on HIV/AIDS progression in perinatally HIV-infected Thai and Cambodian children with distinct clinical patterns; rapid progressors (RPs) and long-term nonprogressors (LTNPs). Materials & methods: APOBEC3G genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in DNA samples. APOBEC3G-mediated G-to-A hypermutations were analyzed by sequencing of the vif/vpu genes from proviral DNA. Results: Frequency of APOBEC3G 186H/R genotypes, AA:AG:GG, in the RPs was 100:0:0% and 83:17:0% (p = 0.3) in LTNPs. Hypermutation of the vif-coding region was observed in none of the RPs and 8.3% of LTNPs (p = 0.5). Hypermutations at the vpu genes were not detected in either groups’ proviral DNA. Conclusion: We observed no significant association of APOBEC3G genotypes and hypermutation rates between children with different profiles of HIV/AIDS disease progression.
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Affiliation(s)
- Torsak Bunupuradah
- HIV-NAT, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok 10330, Thailand
| | - Kazuhiro Matsuoka
- Clinical Research Center, National Hospital Organization Nagoya MedicalCenter, 4-1-1 Sannomaru, Naka-ku, Nagoya, Aichi 460-0001, Japan
| | - Mayumi Imahashi
- Clinical Research Center, National Hospital Organization Nagoya MedicalCenter, 4-1-1 Sannomaru, Naka-ku, Nagoya, Aichi 460-0001, Japan
| | - Yasumasa Iwatani
- Clinical Research Center, National Hospital Organization Nagoya MedicalCenter, 4-1-1 Sannomaru, Naka-ku, Nagoya, Aichi 460-0001, Japan
- Program in Integrated Molecular Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
| | - Jintanat Ananworanich
- HIV-NAT, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok 10330, Thailand
- Current address: US Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720 A, Rockledge Drive, Suite 400, Bethesda, MD 20817, USA
- SEARCH, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok, 10330, Thailand
| | - Thanyawee Puthanakit
- HIV-NAT, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok 10330, Thailand
- Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, 1873, Rama IV Road, Pathumwan, Bangkok, Thailand 10330
| | - Vonthanak Saphonn
- Social Health Clinic, #2, St 289 (Kim Il Sung Blvd), Khan Toul Kok, Phnom Penh, Cambodia
| | - Linda Aurpibul
- Research Institute for Health Sciences, Chiang Mai University, 110 Intavaroros Road, Sriphum, Muang, Chiang Mai, 50200, Thailand
| | - Jiratchaya Sophonphan
- HIV-NAT, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok 10330, Thailand
| | - Tetsuya Yagi
- Department of Infectious Diseases, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
| | - Praphan Phanuphak
- HIV-NAT, the Thai Red Cross AIDS Research Centre, 104 Ratchadamri Road, Pathumwan, Bangkok 10330, Thailand
| | - Wataru Sugiura
- Clinical Research Center, National Hospital Organization Nagoya MedicalCenter, 4-1-1 Sannomaru, Naka-ku, Nagoya, Aichi 460-0001, Japan
- Program in Integrated Molecular Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
- GlaxoSmithKline KK, 6-15, Sendagaya 4-chome, Shibuya-ku, Zip: 151-8566, Tokyo, Japan
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230
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Zhang HL, Liu FL, Jin YB, Deng Q, Liu BL, Zhuo M, Liu XH, Zheng YT, Ling F. The effects of TRIM5α polymorphism on HIV-2ROD and SIVmac239 replication in PBMCs from Chinese rhesus macaques and Vietnamese-origin cynomolgus macaques. Virology 2015; 487:222-9. [PMID: 26550946 DOI: 10.1016/j.virol.2015.10.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 10/22/2022]
Abstract
Because of the difficulty of obtaining Indian-origin rhesus macaques, Chinese-origin rhesus macaques (CR) and Vietnamese-origin cynomolgus macaques (CM) are now used frequently in HIV/AIDS research. Nonetheless, the effects of TRIM5α polymorphism on viral replication in both CR and CM are unclear. To address these questions, we recruited 70 unrelated CR and 40 unrelated CM and studied the effect of TRIM5α polymorphism on HIV-2ROD and SIVmac239 replication in PBMCs. We found that 3 polymorphisms, located in the B30.2 domain of CR TRIM5α formed a haplotype and affected HIV-2ROD replication. In addition, we found that the variant Y178H, located in the Coiled-coil domain of CM TRIM5α, affected TRIM5α-mediated HIV-2ROD restriction. Finally, two polymorphisms, located in the Coiled-coil domain, altered anti-SIVmac239 activity in CR. We concluded that, CM TRIM5α polymorphism could alter HIV-2ROD infection; however, a different domain of CR TRIM5α was responsible for restricting different virus replication.
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Affiliation(s)
- Hui-Ling Zhang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
| | - Feng-Liang Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, PR China
| | - Ya-Bin Jin
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
| | - Qing Deng
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
| | - Bei-Lei Liu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
| | - Min Zhuo
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China
| | - Xiao-Hui Liu
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, PR China
| | - Yong-Tang Zheng
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, PR China.
| | - Fei Ling
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, PR China.
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231
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Harper MS, Guo K, Gibbert K, Lee EJ, Dillon SM, Barrett BS, McCarter MD, Hasenkrug KJ, Dittmer U, Wilson CC, Santiago ML. Interferon-α Subtypes in an Ex Vivo Model of Acute HIV-1 Infection: Expression, Potency and Effector Mechanisms. PLoS Pathog 2015; 11:e1005254. [PMID: 26529416 PMCID: PMC4631339 DOI: 10.1371/journal.ppat.1005254] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/08/2015] [Indexed: 02/07/2023] Open
Abstract
HIV-1 is transmitted primarily across mucosal surfaces and rapidly spreads within the intestinal mucosa during acute infection. The type I interferons (IFNs) likely serve as a first line of defense, but the relative expression and antiviral properties of the 12 IFNα subtypes against HIV-1 infection of mucosal tissues remain unknown. Here, we evaluated the expression of all IFNα subtypes in HIV-1-exposed plasmacytoid dendritic cells by next-generation sequencing. We then determined the relative antiviral potency of each IFNα subtype ex vivo using the human intestinal Lamina Propria Aggregate Culture model. IFNα subtype transcripts from the centromeric half of the IFNA gene complex were highly expressed in pDCs following HIV-1 exposure. There was an inverse relationship between IFNA subtype expression and potency. IFNα8, IFNα6 and IFNα14 were the most potent in restricting HIV-1 infection. IFNα2, the clinically-approved subtype, and IFNα1 were both highly expressed but exhibited relatively weak antiviral activity. The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D. However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity. By contrast, both potent (IFNα8) and weak (IFNα1) subtypes significantly induced HIV-1 GG-to-AG hypermutation. The results unravel non-redundant functions of the IFNα subtypes against HIV-1 infection, with strong implications for HIV-1 mucosal immunity, viral evolution and IFNα-based functional cure strategies.
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Affiliation(s)
- Michael S. Harper
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Immunology and Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kejun Guo
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kathrin Gibbert
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Eric J. Lee
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Stephanie M. Dillon
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Bradley S. Barrett
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Martin D. McCarter
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kim J. Hasenkrug
- Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Ulf Dittmer
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- * E-mail: (UD); (CCW); (MLS)
| | - Cara C. Wilson
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Immunology and Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail: (UD); (CCW); (MLS)
| | - Mario L. Santiago
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Immunology and Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail: (UD); (CCW); (MLS)
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232
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The Ty1 Retrotransposon Restriction Factor p22 Targets Gag. PLoS Genet 2015; 11:e1005571. [PMID: 26451601 PMCID: PMC4599808 DOI: 10.1371/journal.pgen.1005571] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/15/2015] [Indexed: 01/09/2023] Open
Abstract
A novel form of copy number control (CNC) helps maintain a low number of Ty1 retrovirus-like transposons in the Saccharomyces genome. Ty1 produces an alternative transcript that encodes p22, a trans-dominant negative inhibitor of Ty1 retrotransposition whose sequence is identical to the C-terminal half of Gag. The level of p22 increases with copy number and inhibits normal Ty1 virus-like particle (VLP) assembly and maturation through interactions with full length Gag. A forward genetic screen for CNC-resistant (CNCR) mutations in Ty1 identified missense mutations in GAG that restore retrotransposition in the presence of p22. Some of these mutations map within a predicted UBN2 domain found throughout the Ty1/copia family of long terminal repeat retrotransposons, and others cluster within a central region of Gag that is referred to as the CNCR domain. We generated multiple alignments of yeast Ty1-like Gag proteins and found that some Gag proteins, including those of the related Ty2 elements, contain non-Ty1 residues at multiple CNCR sites. Interestingly, the Ty2-917 element is resistant to p22 and does not undergo a Ty1-like form of CNC. Substitutions conferring CNCR map within predicted helices in Ty1 Gag that overlap with conserved sequence in Ty1/copia, suggesting that p22 disturbs a central function of the capsid during VLP assembly. When hydrophobic residues within predicted helices in Gag are mutated, Gag level remains unaffected in most cases yet VLP assembly and maturation is abnormal. Gag CNCR mutations do not alter binding to p22 as determined by co-immunoprecipitation analyses, but instead, exclude p22 from Ty1 VLPs. These findings suggest that the CNCR alleles enhance retrotransposition in the presence of p22 by allowing productive Gag-Gag interactions during VLP assembly. Our work also expands the strategies used by retroviruses for developing resistance to Gag-like restriction factors to now include retrotransposons. The presence of transposable elements in the eukaryotic genome threatens genomic stability and normal gene function, thus various defense mechanisms exist to silence element expression and target integration to benign locations in the genome. Even though the budding yeast Saccharomyces lacks many of the defense systems present in other eukaryotes, including RNAi, DNA methylation, and APOBEC3 proteins, they maintain low numbers of mobile elements in their genome. In the case of the Saccharomyces retrotransposon Ty1, a system called copy number control (CNC) helps determine the number of elements in the genome. Recently, we demonstrated that the mechanism of CNC relies on a trans-acting protein inhibitor of Ty1 expressed from the element itself. This protein inhibitor, called p22, impacts the replication of Ty1 as its copy number increases. To identify a molecular target of p22, mutagenized Ty1 was subjected to a forward genetic screen for CNC-resistance. Mutations in specific domains of Gag, including the UBN2 Gag motif and a novel region we have named the CNCR domain, confer CNCR by preventing the incorporation of p22 into assembling virus-like particles (VLPs), which restores maturation and completion of the Ty1 life cycle. The mechanism of Ty1 inhibition by p22 is conceptually similar to Gag-like restriction factors in mammals since they inhibit normal particle function. In particular, resistance to p22 and the enJS56A1 restriction factor of sheep involves exclusion of the restriction factor during particle assembly, although Ty1 CNCR achieves this in a way that is distinct from the Jaagsiekte retrovirus escape mutants. Our work introduces an intriguing variation on resistance mechanisms to retroviral restriction factors.
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233
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Douam F, Gaska JM, Winer BY, Ding Q, von Schaewen M, Ploss A. Genetic Dissection of the Host Tropism of Human-Tropic Pathogens. Annu Rev Genet 2015; 49:21-45. [PMID: 26407032 DOI: 10.1146/annurev-genet-112414-054823] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Infectious diseases are the second leading cause of death worldwide. Although the host multitropism of some pathogens has rendered their manipulation possible in animal models, the human-restricted tropism of numerous viruses, bacteria, fungi, and parasites has seriously hampered our understanding of these pathogens. Hence, uncovering the genetic basis underlying the narrow tropism of such pathogens is critical for understanding their mechanisms of infection and pathogenesis. Moreover, such genetic dissection is essential for the generation of permissive animal models that can serve as critical tools for the development of therapeutics or vaccines against challenging human pathogens. In this review, we describe different experimental approaches utilized to uncover the genetic foundation regulating pathogen host tropism as well as their relevance for studying the tropism of several important human pathogens. Finally, we discuss the current and future uses of this knowledge for generating genetically modified animal models permissive for these pathogens.
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Affiliation(s)
- Florian Douam
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Jenna M Gaska
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Benjamin Y Winer
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Qiang Ding
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Markus von Schaewen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
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234
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Etienne L, Bibollet-Ruche F, Sudmant PH, Wu LI, Hahn BH, Emerman M. The Role of the Antiviral APOBEC3 Gene Family in Protecting Chimpanzees against Lentiviruses from Monkeys. PLoS Pathog 2015; 11:e1005149. [PMID: 26394054 PMCID: PMC4578921 DOI: 10.1371/journal.ppat.1005149] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/13/2015] [Indexed: 02/07/2023] Open
Abstract
Cross-species transmissions of viruses from animals to humans are at the origin of major human pathogenic viruses. While the role of ecological and epidemiological factors in the emergence of new pathogens is well documented, the importance of host factors is often unknown. Chimpanzees are the closest relatives of humans and the animal reservoir at the origin of the human AIDS pandemic. However, despite being regularly exposed to monkey lentiviruses through hunting, chimpanzees are naturally infected by only a single simian immunodeficiency virus, SIVcpz. Here, we asked why chimpanzees appear to be protected against the successful emergence of other SIVs. In particular, we investigated the role of the chimpanzee APOBEC3 genes in providing a barrier to infection by most monkey lentiviruses. We found that most SIV Vifs, including Vif from SIVwrc infecting western-red colobus, the chimpanzee’s main monkey prey in West Africa, could not antagonize chimpanzee APOBEC3G. Moreover, chimpanzee APOBEC3D, as well as APOBEC3F and APOBEC3H, provided additional protection against SIV Vif antagonism. Consequently, lentiviral replication in primary chimpanzee CD4+ T cells was dependent on the presence of a lentiviral vif gene that could antagonize chimpanzee APOBEC3s. Finally, by identifying and functionally characterizing several APOBEC3 gene polymorphisms in both common chimpanzees and bonobos, we found that these ape populations encode APOBEC3 proteins that are uniformly resistant to antagonism by monkey lentiviruses. Many human pathogens are of zoonotic origin, meaning they originated in animals. This includes HIV-1, the cause of the human AIDS pandemic, which is the result of cross-species transmissions of lentiviruses from chimpanzees and gorillas. However, little is known about the host factors that provide natural protection against viral emergence in a new species. Chimpanzees, which are humans’ closest relatives, harbor only a single lentiviral lineage, despite their frequent exposure to lentiviruses that infect monkeys on which they prey. Here, we investigate the capacity of the accessory protein Vif from different primate lentiviruses to antagonize the APOBEC3 antiviral gene family found in chimpanzees. We found that the Vif protein from most monkey lentiviruses was not able to antagonize chimpanzee APOBEC3G. Furthermore, other APOBEC3 proteins from chimpanzees were also resistant to Vif antagonism. Finally, we showed that, despite polymorphism in the APOBEC3 genes, common chimpanzee and bonobo populations are uniformly resistant to monkey lentiviral Vif antagonism. Our results are consistent with the hypothesis that the host APOBEC3 antiviral proteins protect chimpanzees against many HIV-related viruses commonly found in monkeys.
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Affiliation(s)
- Lucie Etienne
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Frederic Bibollet-Ruche
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Peter H Sudmant
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Lily I Wu
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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Abstract
PURPOSE OF REVIEW To provide updated insights into innate antiviral immunity and highlight prototypical evolutionary features of well characterized HIV restriction factors. RECENT FINDINGS Recently, a new HIV restriction factor, Myxovirus resistance 2, has been discovered and the region/residue responsible for its activity identified using an evolutionary approach. Furthermore, IFI16, an innate immunity protein known to sense several viruses, has been shown to contribute to the defense to HIV-1 by causing cell death upon sensing HIV-1 DNA. SUMMARY Restriction factors against HIV show characteristic signatures of positive selection. Different patterns of accelerated sequence evolution can distinguish antiviral strategies--offense or defence--as well as the level of specificity of the antiviral properties. Sequence analysis of primate orthologs of restriction factors serves to localize functional domains and sites responsible for antiviral action. We use recent discoveries to illustrate how evolutionary genomic analyses help identify new antiviral genes and their mechanisms of action.
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236
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Ahlenstiel CL, Suzuki K, Marks K, Symonds GP, Kelleher AD. Controlling HIV-1: Non-Coding RNA Gene Therapy Approaches to a Functional Cure. Front Immunol 2015; 6:474. [PMID: 26441979 PMCID: PMC4584958 DOI: 10.3389/fimmu.2015.00474] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/31/2015] [Indexed: 12/27/2022] Open
Abstract
The current treatment strategy for HIV-1 involves prolonged and intensive combined antiretroviral therapy (cART), which successfully suppresses plasma viremia. It has transformed HIV-1 infection into a chronic disease. However, despite the success of cART, a latent form of HIV-1 infection persists as integrated provirus in resting memory CD4(+) T cells. Virus can reactivate from this reservoir upon cessation of treatment, and hence HIV requires lifelong therapy. The reservoir represents a major barrier to eradication. Understanding molecular mechanisms regulating HIV-1 transcription and latency are crucial to develop alternate treatment strategies, which impact upon the reservoir and provide a path toward a "functional cure" in which there is no detectable viremia in the absence of cART. Numerous reports have suggested ncRNAs are involved in regulating viral transcription and latency. This review will discuss the latest developments in ncRNAs, specifically short interfering (si)RNA and short hairpin (sh)RNA, targeting molecular mechanisms of HIV-1 transcription, which may represent potential future therapeutics. It will also briefly address animal models for testing potential therapeutics and current gene therapy clinical trials.
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Affiliation(s)
| | - Kazuo Suzuki
- The Kirby Institute, UNSW Australia, Sydney, NSW, Australia
- Immunovirology Laboratory, St. Vincent’s Centre for Applied Medical Research, Darlinghurst, NSW, Australia
| | - Katherine Marks
- Immunovirology Laboratory, St. Vincent’s Centre for Applied Medical Research, Darlinghurst, NSW, Australia
| | | | - Anthony D. Kelleher
- The Kirby Institute, UNSW Australia, Sydney, NSW, Australia
- Immunovirology Laboratory, St. Vincent’s Centre for Applied Medical Research, Darlinghurst, NSW, Australia
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237
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A multi-scale mathematical modeling framework to investigate anti-viral therapeutic opportunities in targeting HIV-1 accessory proteins. J Theor Biol 2015; 386:89-104. [PMID: 26385832 DOI: 10.1016/j.jtbi.2015.08.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/13/2015] [Accepted: 08/31/2015] [Indexed: 02/03/2023]
Abstract
Human immunodeficiency virus-1 (HIV-1) employs accessory proteins to evade innate immune responses by neutralizing the anti-viral activity of host restriction factors. Apolipoprotein B mRNA-editing enzyme 3G (APOBEC3G, A3G) and bone marrow stromal cell antigen 2 (BST2) are host resistance factors that potentially inhibit HIV-1 infection. BST2 reduces viral production by tethering budding HIV-1 particles to virus producing cells, while A3G inhibits the reverse transcription (RT) process and induces viral genome hypermutation through cytidine deamination, generating fewer replication competent progeny virus. Two HIV-1 proteins counter these cellular restriction factors: Vpu, which reduces surface BST2, and Vif, which degrades cellular A3G. The contest between these host and viral proteins influences whether HIV-1 infection is established and progresses towards AIDS. In this work, we present an age-structured multi-scale viral dynamics model of in vivo HIV-1 infection. We integrated the intracellular dynamics of anti-viral activity of the host factors and their neutralization by HIV-1 accessory proteins into the virus/cell population dynamics model. We calculate the basic reproductive ratio (Ro) as a function of host-viral protein interaction coefficients, and numerically simulated the multi-scale model to understand HIV-1 dynamics following host factor-induced perturbations. We found that reducing the influence of Vpu triggers a drop in Ro, revealing the impact of BST2 on viral infection control. Reducing Vif׳s effect reveals the restrictive efficacy of A3G in blocking RT and in inducing lethal hypermutations, however, neither of these factors alone is sufficient to fully restrict HIV-1 infection. Interestingly, our model further predicts that BST2 and A3G function synergistically, and delineates their relative contribution in limiting HIV-1 infection and disease progression. We provide a robust modeling framework for devising novel combination therapies that target HIV-1 accessory proteins and boost antiviral activity of host factors.
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238
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Anderson BD, Harris RS. Transcriptional regulation of APOBEC3 antiviral immunity through the CBF-β/RUNX axis. SCIENCE ADVANCES 2015; 1:e1500296. [PMID: 26601257 PMCID: PMC4643775 DOI: 10.1126/sciadv.1500296] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/03/2015] [Indexed: 06/05/2023]
Abstract
A diverse set of innate immune mechanisms protects cells from viral infections. The APOBEC3 family of DNA cytosine deaminases is an integral part of these defenses. For instance, APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H would have the potential to destroy HIV-1 complementary DNA replication intermediates if not for neutralization by a proteasomal degradation mechanism directed by the viral protein Vif. At the core of this complex, Vif heterodimerizes with the transcription cofactor CBF-β, which results in fewer transcription complexes between CBF-β and its normal RUNX partners. Recent studies have shown that the Vif/CBF-β interaction is specific to the primate lentiviruses HIV-1 and SIV (simian immunodeficiency virus), although related nonprimate lentiviruses still require a Vif-dependent mechanism for protection from host species' APOBEC3 enzymes. We provide a molecular explanation for this evolutionary conundrum by showing that CBF-β is required for expression of the aforementioned HIV-1-restrictive APOBEC3 gene repertoire. Knockdown and knockout studies demonstrate that CBF-β is required for APOBEC3 mRNA expression in the nonpermissive T cell line H9 and in primary CD4(+) T lymphocytes. Complementation experiments using CBF-β separation-of-function alleles show that the interaction with RUNX transcription factors is required for APOBEC3 transcriptional regulation. Accordingly, the infectivity of Vif-deficient HIV-1 increases in cells lacking CBF-β, demonstrating the importance of CBF-β/RUNX-mediated transcription in establishing the APOBEC3 antiviral state. These findings demonstrate a major layer of APOBEC3 gene regulation in lymphocytes and suggest that primate lentiviruses evolved to hijack CBF-β in order to simultaneously suppress this potent antiviral defense system at both transcriptional and posttranslational levels.
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239
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Abstract
PURPOSE OF REVIEW HIV genetic diversity poses major challenges for the prevention, control, and cure of infection. Characterizing the diversity and evolution of HIV populations within the host provides insights into the mechanisms of HIV persistence during antiretroviral therapy (ART). This review describes the HIV diversity within patients, how it is affected by suppressive ART, and makes a case for early treatment after HIV infection. RECENT FINDINGS HIV evolution is effectively halted by ART. However, cells that were infected prior to initiating therapy can proliferate to very high numbers both before and during treatment. Such clonal expansions result in the persistence of integrated proviruses despite therapy. These expanding proviruses have been shown to be a source for residual viremia during ART, and they may be a source for viral rebound after interrupting ART. SUMMARY Plasma HIV RNA shows no evidence for evolution during ART, suggesting that HIV persistence is not driven by low-level, ongoing replication. The emergence of identical viral sequences observed in both HIV RNA and DNA is likely due to proliferation of infected cells. Early treatment restricts the viral population and reduces the number of variants that must be targeted for future therapeutic strategies.
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240
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Gentili M, Kowal J, Tkach M, Satoh T, Lahaye X, Conrad C, Boyron M, Lombard B, Durand S, Kroemer G, Loew D, Dalod M, Théry C, Manel N. Transmission of innate immune signaling by packaging of cGAMP in viral particles. Science 2015; 349:1232-6. [PMID: 26229115 DOI: 10.1126/science.aab3628] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/22/2015] [Indexed: 12/20/2022]
Abstract
Infected cells detect viruses through a variety of receptors that initiate cell-intrinsic innate defense responses. Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) is a cytosolic sensor for many DNA viruses and HIV-1. In response to cytosolic viral DNA, cGAS synthesizes the second messenger 2'3'-cyclic GMP-AMP (cGAMP), which activates antiviral signaling pathways. We show that in cells producing virus, cGAS-synthesized cGAMP can be packaged in viral particles and extracellular vesicles. Viral particles efficiently delivered cGAMP to target cells. cGAMP transfer by viral particles to dendritic cells activated innate immunity and antiviral defenses. Finally, we show that cell-free murine cytomegalovirus and Modified Vaccinia Ankara virus contained cGAMP. Thus, transfer of cGAMP by viruses may represent a defense mechanism to propagate immune responses to uninfected target cells.
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Affiliation(s)
- Matteo Gentili
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Joanna Kowal
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Mercedes Tkach
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Takeshi Satoh
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Xavier Lahaye
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Cécile Conrad
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France
| | - Marilyn Boyron
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, INSERM U1104, CNRS UMR7280, 13288 Marseille, France
| | - Bérangère Lombard
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Paris, France
| | | | - Guido Kroemer
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, 94805 Villejuif, France
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Paris, France
| | - Marc Dalod
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, INSERM U1104, CNRS UMR7280, 13288 Marseille, France
| | - Clotilde Théry
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France. Labex Dendritic Cell Biology (DCBIOL), Paris, France
| | - Nicolas Manel
- INSERM U932, Immunity and Cancer Unit, Institut Curie, Paris, France. Labex Dendritic Cell Biology (DCBIOL), Paris, France. Labex Vaccine Research Institute (VRI), Paris, France.
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241
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Garg A, Kaul D, Chauhan N. APOBEC3G governs to ensure cellular oncogenic transformation. Blood Cells Mol Dis 2015; 55:248-54. [PMID: 26227855 DOI: 10.1016/j.bcmd.2015.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/14/2015] [Accepted: 07/14/2015] [Indexed: 01/01/2023]
Abstract
The oncogenic potential of APOBEC3G gene was recently appreciated by the finding that revealed inhibitory influence of APOBEC3G upon micro-RNA mediated repression of the gene responsible for hepatic metastasis. Here we report for the first time that sustained APOBEC3G expression is the characteristic trait exhibited by various cancer cells of different tissue origins as well as APOBEC3G represses cellular gene coding for tumor suppressor KLF4 by binding to its mRNA. This phenomenon was paralleled by the sustained expression of the cellular SP1 which ensured overexpression of genes coding for c-myc, Bmi-1, BCL-2 and MDM2 coupled with downregulation of tumor suppressor p53 thereby creating a favorable situation for oncogenic transformation.
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Affiliation(s)
- Anuradha Garg
- Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India.
| | - Deepak Kaul
- Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India.
| | - Nalini Chauhan
- Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India.
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242
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Leng J, Ho HP, Buzon MJ, Pereyra F, Walker BD, Yu XG, Chang EJ, Lichterfeld M. A cell-intrinsic inhibitor of HIV-1 reverse transcription in CD4(+) T cells from elite controllers. Cell Host Microbe 2015; 15:717-728. [PMID: 24922574 DOI: 10.1016/j.chom.2014.05.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/30/2014] [Accepted: 04/23/2014] [Indexed: 01/22/2023]
Abstract
HIV-1 reverse transcription represents the predominant target for pharmacological inhibition of viral replication, but cell-intrinsic mechanisms that can block HIV-1 reverse transcription in a clinically significant way are poorly defined. We find that effective HIV-1 reverse transcription depends on the phosphorylation of viral reverse transcriptase by host cyclin-dependent kinase (CDK) 2 at a highly conserved Threonine residue. CDK2-dependent phosphorylation increased the efficacy and stability of viral reverse transcriptase and enhanced viral fitness. Interestingly, p21, a cell-intrinsic CDK inhibitor that is upregulated in CD4(+) T cells from "elite controllers," potently inhibited CDK2-dependent phosphorylation of HIV-1 reverse transcriptase and significantly reduced the efficacy of viral reverse transcription. These data suggest that p21 can indirectly block HIV-1 reverse transcription by inhibiting host cofactors supporting HIV-1 replication and identify sites of viral vulnerability that are effectively targeted in persons with natural control of HIV-1 replication.
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Affiliation(s)
- Jin Leng
- Infectious Disease Division, Massachusetts General Hospital, Boston, MA, USA.,Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Hsin-Pin Ho
- Department of Chemistry, York College and the Graduate Center, City University of New York, New York, NY, USA
| | - Maria J Buzon
- Infectious Disease Division, Massachusetts General Hospital, Boston, MA, USA.,Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Florencia Pereyra
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.,Infectious Disease Division, Brigham and Women's Hospital, Boston, MA, USA
| | - Bruce D Walker
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Xu G Yu
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Emmanuel J Chang
- Department of Chemistry, York College and the Graduate Center, City University of New York, New York, NY, USA
| | - Mathias Lichterfeld
- Infectious Disease Division, Massachusetts General Hospital, Boston, MA, USA
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243
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Pery E, Sheehy A, Miranda Nebane N, Misra V, Mankowski MK, Rasmussen L, Lucile White E, Ptak RG, Gabuzda D. Redoxal, an inhibitor of de novo pyrimidine biosynthesis, augments APOBEC3G antiviral activity against human immunodeficiency virus type 1. Virology 2015; 484:276-287. [PMID: 26141568 DOI: 10.1016/j.virol.2015.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/05/2015] [Accepted: 06/11/2015] [Indexed: 12/31/2022]
Abstract
APOBEC3G (A3G) is a cytidine deaminase that restricts HIV-1 replication by inducing G-to-A hypermutation in viral DNA; deamination-independent mechanisms are also implicated. HIV-1 Vif protein counteracts A3G by inducing its proteasomal degradation. Thus, the Vif-A3G axis is a potential therapeutic target. To identify compounds that inhibit Vif:A3G interaction, a 307,520 compound library was tested in a TR-FRET screen. Two identified compounds, redoxal and lomofungin, inhibited HIV-1 replication in peripheral blood mononuclear cells. Lomofungin activity was linked to A3G, but not pursued further due to cytotoxicity. Redoxal displayed A3G-dependent restriction, inhibiting viral replication by stabilizing A3G protein levels and increasing A3G in virions. A3G-independent activity was also detected. Treatment with uridine or orotate, intermediates of pyrimidine synthesis, diminished redoxal-induced stabilization of A3G and antiviral activity. These results identify redoxal as an inhibitor of HIV-1 replication and suggest its ability to inhibit pyrimidine biosynthesis suppresses viral replication by augmenting A3G antiviral activity.
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Affiliation(s)
- Erez Pery
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, Boston, MA 02115, United States; Department of Pathology, Harvard Medical School, Boston, MA 02115, United States
| | - Ann Sheehy
- Department of Biology, College of the Holy Cross, Worcester, MA 01610, United States
| | - N Miranda Nebane
- Southern Research Institute High Throughput Screening Center, Birmingham, AL 35205, United States
| | - Vikas Misra
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, Boston, MA 02115, United States
| | - Marie K Mankowski
- Southern Research Institute, Department of Infectious Disease Research, Frederick, MD 21701, United States
| | - Lynn Rasmussen
- Southern Research Institute High Throughput Screening Center, Birmingham, AL 35205, United States
| | - E Lucile White
- Southern Research Institute High Throughput Screening Center, Birmingham, AL 35205, United States
| | - Roger G Ptak
- Southern Research Institute, Department of Infectious Disease Research, Frederick, MD 21701, United States
| | - Dana Gabuzda
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, Boston, MA 02115, United States; Department of Neurology (Microbiology), Harvard Medical School, Boston, MA 02115, United States.
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244
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Adoro S, Cubillos-Ruiz JR, Chen X, Deruaz M, Vrbanac VD, Song M, Park S, Murooka TT, Dudek TE, Luster AD, Tager AM, Streeck H, Bowman B, Walker BD, Kwon DS, Lazarevic V, Glimcher LH. IL-21 induces antiviral microRNA-29 in CD4 T cells to limit HIV-1 infection. Nat Commun 2015; 6:7562. [PMID: 26108174 PMCID: PMC4481879 DOI: 10.1038/ncomms8562] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 05/20/2015] [Indexed: 01/15/2023] Open
Abstract
Initial events after exposure determine HIV-1 disease progression, underscoring a critical need to understand host mechanisms that interfere with initial viral replication. Although associated with chronic HIV-1 control, it is not known whether interleukin-21 (IL-21) contributes to early HIV-1 immunity. Here we take advantage of tractable primary human lymphoid organ aggregate cultures to show that IL-21 directly suppresses HIV-1 replication, and identify microRNA-29 (miR-29) as an antiviral factor induced by IL-21 in CD4 T cells. IL-21 promotes transcription of all miR-29 species through STAT3, whose binding to putative regulatory regions within the MIR29 gene is enriched by IL-21 signalling. Notably, exogenous IL-21 limits early HIV-1 infection in humanized mice, and lower viremia in vivo is associated with higher miR-29 expression. Together, these findings reveal a novel antiviral IL-21-miR-29 axis that promotes CD4 T-cell-intrinsic resistance to HIV-1 infection, and suggest a role for IL-21 in initial HIV-1 control in vivo. HIV-infected patients who maintain undetectable virus levels possess elevated plasma concentrations of IL-21. Here, Adoro et al. show that IL-21 inhibits early viral infection in humanized mice and suppresses HIV-1 replication in vitro by upregulating a microRNA via the regulatory protein STAT3.
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Affiliation(s)
- Stanley Adoro
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA.,Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
| | - Juan R Cubillos-Ruiz
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA.,Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
| | - Xi Chen
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA
| | - Maud Deruaz
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Vladimir D Vrbanac
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA.,Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Minkyung Song
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA
| | - Suna Park
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA
| | - Thomas T Murooka
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Timothy E Dudek
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
| | - Andrew D Luster
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Andrew M Tager
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA.,Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Hendrik Streeck
- Institute for Medical Biology, University Hospital Essen, University of Duisburg-Essen, Essen D-45147, Germany
| | - Brittany Bowman
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
| | - Bruce D Walker
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20814, USA
| | - Douglas S Kwon
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
| | - Vanja Lazarevic
- Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA
| | - Laurie H Glimcher
- Department of Medicine, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, New York 10065, USA.,Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139, USA
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245
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Holmes M, Zhang F, Bieniasz PD. Single-Cell and Single-Cycle Analysis of HIV-1 Replication. PLoS Pathog 2015; 11:e1004961. [PMID: 26086614 PMCID: PMC4472667 DOI: 10.1371/journal.ppat.1004961] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 05/18/2015] [Indexed: 12/12/2022] Open
Abstract
The dynamics of the late stages of the HIV-1 life cycle are poorly documented. Viral replication dynamics are typically measured in populations of infected cells, but asynchrony that is introduced during the early steps of HIV-1 replication complicates the measurement of the progression of subsequent steps and can mask replication dynamics and their variation in individual infected cells. We established microscopy-based methods to dynamically measure HIV-1-encoded reporter gene and antiviral gene expression in individual infected cells. We coupled these measurements with conventional analyses to quantify delays in the HIV-1 replication cycle imposed by the biphasic nature of HIV-1 gene expression and by the assembly-inhibiting property of the matrix domain of Gag. We further related the dynamics of restriction factor (APOBEC3G) removal to the dynamics of HIV-1 replication in individual cells. These studies provide a timeline for key events in the HIV-1 replication cycle, and reveal that the interval between the onset of early and late HIV-1 gene expression is only ~3h, but matrix causes a ~6–12h delay in the generation of extracellular virions. Interestingly, matrix delays particle assembly to a time at which APOBEC3G has largely been removed from the cell. Thus, a need to prepare infected cells to be efficient producers of infectious HIV-1 may provide an impetus for programmed delays in HIV-1 virion genesis. Our findings also emphasize the significant heterogeneity in the length of the HIV-1 replication cycle in homogenous cell populations and suggest that a typical infected cell generates new virions for only a few hours at the end of a 48h lifespan. Therefore, small changes in the lifespan of infected cells might have a large effect on viral yield in a single cycle and the overall clinical course in infected individuals. The HIV-1 replication cycle is composed of several sequential steps. While the timing of the early steps of HIV-1 replication is quite well understood, measuring the duration of later steps is complicated by the fact that asynchrony is introduced into populations of infected cells during early steps. We devised imaging methods for measuring the duration of late steps in HIV-1 replication in single infected cells, circumventing the problems associated with measurements in populations of asynchronously infected cells. By combining these measurements with conventional analyses of HIV-1 replication in populations of cells, we derived a time-line of key events during the late steps of the HIV-1 life cycle. We find that the delay between early and late gene expression is small but that a subsequent programmed delay in virus assembly enables HIV-1 to remove a host antiviral protein from infected cells before new virions are generated. In so doing, HIV-1 may prevent futile virion production.
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Affiliation(s)
- Mowgli Holmes
- Columbia University, New York, New York, United States of America
- Aaron Diamond AIDS Research Center and Laboratory of Retrovirology, The Rockefeller University, New York, New York, United States of America
| | - Fengwen Zhang
- Aaron Diamond AIDS Research Center and Laboratory of Retrovirology, The Rockefeller University, New York, New York, United States of America
| | - Paul D. Bieniasz
- Aaron Diamond AIDS Research Center and Laboratory of Retrovirology, The Rockefeller University, New York, New York, United States of America
- Howard Hughes Medical Institute, New York, New York, United States of America
- * E-mail:
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246
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Kouno T, Luengas EM, Shigematsu M, Shandilya SMD, Zhang J, Chen L, Hara M, Schiffer CA, Harris RS, Matsuo H. Structure of the Vif-binding domain of the antiviral enzyme APOBEC3G. Nat Struct Mol Biol 2015; 22:485-91. [PMID: 25984970 PMCID: PMC4456288 DOI: 10.1038/nsmb.3033] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 04/21/2015] [Indexed: 12/24/2022]
Abstract
The human APOBEC3G (A3G) DNA cytosine deaminase restricts and hypermutates DNA-based parasites including HIV-1. The viral infectivity factor (Vif) prevents restriction by triggering A3G degradation. While the structure of the A3G catalytic domain is known, the structure of the N-terminal Vif-binding domain has proven more elusive. Here, evolution- and structure-guided mutagenesis was used to solubilize the Vif-binding domain of A3G permitting structural determination by NMR spectroscopy. A smaller zinc-coordinating pocket and altered helical packing distinguish it from catalytic domain structures, and help explain the reported inactivity of this domain. This soluble A3G N-terminal domain is bound by Vif, which enabled mutagenesis and biochemical experiments to identify a unique Vif-interacting surface formed by α1-β1, β2-α2, and β4-α4 loops. This structure sheds new light on the Vif-A3G interaction and provides critical information for future drug development.
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Affiliation(s)
- Takahide Kouno
- 1] Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA. [2] Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Elizabeth M Luengas
- Biochemistry, Molecular Biology and Biophysics Department, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Megumi Shigematsu
- Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shivender M D Shandilya
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - JingYing Zhang
- Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Luan Chen
- Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mayuko Hara
- Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Reuben S Harris
- Biochemistry, Molecular Biology and Biophysics Department, Masonic Cancer Center, Center for Genome Engineering, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Hiroshi Matsuo
- Biochemistry, Molecular Biology and Biophysics Department, Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 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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248
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Doyle T, Goujon C, Malim MH. HIV-1 and interferons: who's interfering with whom? Nat Rev Microbiol 2015; 13:403-13. [PMID: 25915633 DOI: 10.1038/nrmicro3449] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The ability of interferons (IFNs) to inhibit HIV-1 replication in cell culture models has long been recognized, and the therapeutic administration of IFNα to HIV-1-infected patients who are not receiving antiretroviral therapy produces a clear but transient decrease in plasma viral load. Conversely, studies of chronic HIV-1 infection in humans and SIV-infected animal models of AIDS show positive correlations between elevated plasma levels of IFNs, increased expression of IFN-stimulated genes (ISGs), biomarkers of inflammation and disease progression. In this Review, we discuss the evidence that IFNs can control HIV-1 replication in vivo and debate the controversial role of IFNs in promoting the pathological sequelae of chronic HIV-1 infection.
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Affiliation(s)
- Tomas Doyle
- Department of Infectious Diseases, King's College London, 2nd Floor, Borough Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK
| | - Caroline Goujon
- Department of Infectious Diseases, King's College London, 2nd Floor, Borough Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK
| | - Michael H Malim
- Department of Infectious Diseases, King's College London, 2nd Floor, Borough Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK
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249
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Wang Y, Lavender P, Watson J, Arno M, Lehner T. Stress-activated Dendritic Cells (DC) Induce Dual Interleukin (IL)-15- and IL1β-mediated Pathways, Which May Elicit CD4+ Memory T Cells and Interferon (IFN)-stimulated Genes. J Biol Chem 2015; 290:15595-15609. [PMID: 25907558 DOI: 10.1074/jbc.m115.645754] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Indexed: 01/03/2023] Open
Abstract
The prevailing evidence suggests that immunological memory does not require antigenic re-stimulation but is maintained by low level tonic stimulation. We examined the hypothesis that stress agents contribute to tonic cellular activation and maintain immunological memory. Stimulation of monocyte-derived dendritic cells (DC) with stress agents elicits reactive oxygen species and HSP70. NFκB is activated, which up-regulates membrane-associated (ma) IL-15, caspase-1 and IL-1β. Co-culture of stress-treated DC with mononuclear cells activates IL-15 and IL-1β receptors on CD4(+) T cells, eliciting CD40L, proliferation, and up-regulation of CD45RO(+) memory T cells. The transcription factors Tbet(high) and RORγt are up-regulated, whereas FoxP3 is down-regulated, resulting in enhanced Th1 and Th17 expression and the corresponding cytokines. The interaction between maIL-15 expressed by DC and IL-15R on CD4(+) T cells results in one pathway and the corresponding cells expressing IL-1β and IL1βR as a second pathway. Importantly, inhibition studies with IL-15 antibodies and IL-1βR inhibitor suggest that both pathways may be required for optimum CD4(+) CD45RO(+) memory T cell expression. Type 1 IFN expression in splenic CD11c DC of stress-treated mice demonstrated a significant increase of IFN-α in CD11c CD317(+) and CD8α(+) DC. Analysis of RNA in human CD4(+) memory T cells showed up-regulation of type 1 IFN-stimulated genes and inhibition with histone methyltransferase inhibitor. We suggest the paradigm that stress-induced tonic stimulation might be responsible for the robust persistence of the immune response in vaccination and that epigenetic changes are involved in maintaining CD4(+) T cell memory.
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Affiliation(s)
- Yufei Wang
- Mucosal Immunology Unit, Kings College London, London SE1 1UL, United Kingdom
| | - Paul Lavender
- MRC, and Asthma UK Centre in Allergic Mechanisms of Asthma, Kings College London, London SE1 1UL, United Kingdom
| | - Julie Watson
- MRC, and Asthma UK Centre in Allergic Mechanisms of Asthma, Kings College London, London SE1 1UL, United Kingdom
| | - Matthew Arno
- Genomics Centre, Kings College London, London SE1 1UL, United Kingdom
| | - Thomas Lehner
- Mucosal Immunology Unit, Kings College London, London SE1 1UL, United Kingdom.
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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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