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Hagelauer E, Lotke R, Kmiec D, Hu D, Hohner M, Stopper S, Nchioua R, Kirchhoff F, Sauter D, Schindler M. Tetherin Restricts SARS-CoV-2 despite the Presence of Multiple Viral Antagonists. Viruses 2023; 15:2364. [PMID: 38140605 PMCID: PMC10747847 DOI: 10.3390/v15122364] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
Coronavirus infection induces interferon-stimulated genes, one of which encodes Tetherin, a transmembrane protein inhibiting the release of various enveloped viruses from infected cells. Previous studies revealed that SARS-CoV encodes two Tetherin antagonists: the Spike protein (S), inducing lysosomal degradation of Tetherin, and ORF7a, altering its glycosylation. Similarly, SARS-CoV-2 has also been shown to use ORF7a and Spike to enhance virion release in the presence of Tetherin. Here, we directly compare the abilities and mechanisms of these two viral proteins to counteract Tetherin. Therefore, cell surface and total Tetherin levels upon ORF7a or S expression were investigated using flow cytometry and Western blot analysis. SARS-CoV and SARS-CoV-2 S only marginally reduced Tetherin cell surface levels in a cell type-dependent manner. In HEK293T cells, under conditions of high exogenous Tetherin expression, SARS-CoV-2 S and ORF7a reduced total cellular Tetherin levels much more efficiently than the respective counterparts derived from SARS-CoV. Nevertheless, ORF7a from both species was able to alter Tetherin glycosylation. The ability to decrease total protein levels of Tetherin was conserved among S proteins from different SARS-CoV-2 variants (α, γ, δ, ο). While SARS-CoV-2 S and ORF7a both colocalized with Tetherin, only ORF7a directly interacted with the restriction factor in a two-hybrid assay. Despite the presence of multiple Tetherin antagonists, SARS-CoV-2 replication in Caco-2 cells was further enhanced upon Tetherin knockout. Altogether, our data show that endogenous Tetherin restricts SARS-CoV-2 replication and that the antiviral activity of Tetherin is only partially counteracted by viral antagonists with differential and complementary modes of action.
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Affiliation(s)
- Elena Hagelauer
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Rishikesh Lotke
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany; (D.K.); (R.N.); (F.K.)
| | - Dan Hu
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Mirjam Hohner
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Sophie Stopper
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Rayhane Nchioua
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany; (D.K.); (R.N.); (F.K.)
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany; (D.K.); (R.N.); (F.K.)
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany; (E.H.); (R.L.); (D.H.); (M.H.); (S.S.); (D.S.)
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Leifels M, Khalilur Rahman O, Sam IC, Cheng D, Chua FJD, Nainani D, Kim SY, Ng WJ, Kwok WC, Sirikanchana K, Wuertz S, Thompson J, Chan YF. The one health perspective to improve environmental surveillance of zoonotic viruses: lessons from COVID-19 and outlook beyond. ISME COMMUNICATIONS 2022; 2:107. [PMID: 36338866 PMCID: PMC9618154 DOI: 10.1038/s43705-022-00191-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/26/2022] [Accepted: 10/11/2022] [Indexed: 11/11/2022]
Abstract
The human population has doubled in the last 50 years from about 3.7 billion to approximately 7.8 billion. With this rapid expansion, more people live in close contact with wildlife, livestock, and pets, which in turn creates increasing opportunities for zoonotic diseases to pass between animals and people. At present an estimated 75% of all emerging virus-associated infectious diseases possess a zoonotic origin, and outbreaks of Zika, Ebola and COVID-19 in the past decade showed their huge disruptive potential on the global economy. Here, we describe how One Health inspired environmental surveillance campaigns have emerged as the preferred tools to monitor human-adjacent environments for known and yet to be discovered infectious diseases, and how they can complement classical clinical diagnostics. We highlight the importance of environmental factors concerning interactions between animals, pathogens and/or humans that drive the emergence of zoonoses, and the methodologies currently proposed to monitor them-the surveillance of wastewater, for example, was identified as one of the main tools to assess the spread of SARS-CoV-2 by public health professionals and policy makers during the COVID-19 pandemic. One-Health driven approaches that facilitate surveillance, thus harbour the potential of preparing humanity for future pandemics caused by aetiological agents with environmental reservoirs. Via the example of COVID-19 and other viral diseases, we propose that wastewater surveillance is a useful complement to clinical diagnosis as it is centralized, robust, cost-effective, and relatively easy to implement.
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Affiliation(s)
- Mats Leifels
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Omar Khalilur Rahman
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - I-Ching Sam
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Medical Microbiology, University Malaya Medical Centre, Kuala Lumpur, Malaysia
| | - Dan Cheng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Feng Jun Desmond Chua
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Dhiraj Nainani
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Se Yeon Kim
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Wei Jie Ng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Wee Chiew Kwok
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kwanrawee Sirikanchana
- Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
- Centre of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education, Bangkok, Thailand
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
| | - Janelle Thompson
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Yoke Fun Chan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Curlin JZ, Schmitt K, Remling-Mulder L, Moriarty R, Baczenas JJ, Goff K, O’Connor S, Stenglein M, Marx PA, Akkina R. In vivo infection dynamics and human adaptive changes of SIVsm-derived viral siblings SIVmac239, SIV B670 and SIVhu in humanized mice as a paralog of HIV-2 genesis. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2021; 1:813606. [PMID: 37168442 PMCID: PMC10168645 DOI: 10.3389/fviro.2021.813606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Simian immunodeficiency virus native to sooty mangabeys (SIVsm) is believed to have given rise to HIV-2 through cross-species transmission and evolution in the human. SIVmac239 and SIVB670, pathogenic to macaques, and SIVhu, isolated from an accidental human infection, also have origins in SIVsm. With their common ancestral lineage as that of HIV-2 from the progenitor SIVsm, but with different passage history in different hosts, they provide a unique opportunity to evaluate cross-species transmission to a new host and their adaptation/evolution both in terms of potential genetic and phenotypic changes. Using humanized mice with a transplanted human system, we evaluated in vivo replication kinetics, CD4+ T cell dynamics and genetic adaptive changes during serial passage with a goal to understand their evolution under human selective immune pressure. All the three viruses readily infected hu-mice causing chronic viremia. While SIVmac and SIVB670 caused CD4+ T cell depletion during sequential passaging, SIVhu with a deletion in nef gene was found to be less pathogenic. Deep sequencing of the genomes of these viruses isolated at different times revealed numerous adaptive mutations of significance that increased in frequency during sequential passages. The ability of these viruses to infect and replicate in humanized mice provides a new small animal model to study SIVs in vivo in addition to more expensive macaques. Since SIVmac and related viruses have been indispensable in many areas of HIV pathogenesis, therapeutics and cure research, availability of this small animal hu-mouse model that is susceptible to both SIV and HIV viruses is likely to open novel avenues of investigation for comparative studies using the same host.
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Affiliation(s)
- James Z. Curlin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
- Antiviral Discovery, Evaluation and Application Research (ADEAR) Training Program, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kimberly Schmitt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Leila Remling-Mulder
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Ryan Moriarty
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - John J. Baczenas
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kelly Goff
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Shelby O’Connor
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mark Stenglein
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Preston A. Marx
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane National Primate Research Center, Covington, LA, USA
| | - Ramesh Akkina
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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APOBEC3F Constitutes a Barrier to Successful Cross-Species Transmission of Simian Immunodeficiency Virus SIVsmm to Humans. J Virol 2021; 95:e0080821. [PMID: 34132575 DOI: 10.1128/jvi.00808-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Simian immunodeficiency virus infecting sooty mangabeys (SIVsmm) has been transmitted to humans on at least nine occasions, giving rise to human immunodeficiency virus type 2 (HIV-2) groups A to I. SIVsmm isolates replicate in human T cells and seem capable of overcoming major human restriction factors without adaptation. However, only groups A and B are responsible for the HIV-2 epidemic in sub-Saharan Africa, and it is largely unclear whether adaptive changes were associated with spread in humans. To address this, we examined the sensitivity of infectious molecular clones (IMCs) of five HIV-2 strains and representatives of five different SIVsmm lineages to various APOBEC3 proteins. We confirmed that SIVsmm strains replicate in human T cells, albeit with more variable replication fitness and frequently lower efficiency than HIV-2 IMCs. Efficient viral propagation was generally dependent on intact vif genes, highlighting the need for counteraction of APOBEC3 proteins. On average, SIVsmm was more susceptible to inhibition by human APOBEC3D, -F, -G, and -H than HIV-2. For example, human APOBEC3F reduced infectious virus yield of SIVsmm by ∼80% but achieved only ∼40% reduction in the case of HIV-2. Functional and mutational analyses of human- and monkey-derived alleles revealed that an R128T polymorphism in APOBEC3F contributes to species-specific counteraction by HIV-2 and SIVsmm Vifs. In addition, a T84S substitution in SIVsmm Vif increased its ability to counteract human APOBEC3F. Altogether, our results confirm that SIVsmm Vif proteins show intrinsic activity against human APOBEC3 proteins but also demonstrate that epidemic HIV-2 strains evolved an increased ability to counteract this class of restriction factors during human adaptation. IMPORTANCE Viral zoonoses pose a significant threat to human health, and it is important to understand determining factors. SIVs infecting great apes gave rise to HIV-1. In contrast, SIVs infecting African monkey species have not been detected in humans, with one notable exception. SIVsmm from sooty mangabeys has crossed the species barrier to humans on at least nine independent occasions and seems capable of overcoming many innate defense mechanisms without adaptation. Here, we confirmed that SIVsmm Vif proteins show significant activity against human APOBEC3 proteins. Our analyses also revealed, however, that different lineages of SIVsmm are significantly more susceptible to inhibition by various human APOBEC3 proteins than HIV-2 strains. Mutational analyses suggest that an R128T substitution in APOBEC3F and a T84S change in Vif contribute to species-specific counteraction by HIV-2 and SIVsmm. Altogether, our results support that epidemic HIV-2 strains acquired increased activity against human APOBEC3 proteins to clear this restrictive barrier.
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Slow Receptor Binding of the Noncytopathic HIV-2 UC1 Envs Is Balanced by Long-Lived Activation State and Efficient Fusion Activity. Cell Rep 2021; 31:107749. [PMID: 32521274 DOI: 10.1016/j.celrep.2020.107749] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2020] [Accepted: 05/18/2020] [Indexed: 01/08/2023] Open
Abstract
Many HIV strains downregulate the levels of CD4 receptor on the surface of infected cells to prevent superinfection. In contrast, the rare HIV-2UC1 strain is noncytopathic and has no effect on CD4 expression in infected cells but still replicates as efficiently as more cytopathic strains in peripheral blood mononuclear cells (PBMCs). Here, we show that HIV-2UC1 Env interactions with the CD4 receptor exhibit slow association kinetics, whereas the dissociation kinetics is within the range of cytopathic strains. Despite the resulting 10- to 100-fold decrease in binding affinity, HIV-2UC1 Envs exhibit long-lived activation state and efficient fusion activity. These observations suggest that HIV-2UC1 Envs evolved to balance low affinity with an improved and readily triggerable molecular machinery to mediate entry. Resistance to cold exposure, similar to many primary HIV-1 isolates, and to sCD4 neutralization suggests that HIV-2UC1 Envs preferentially sample a closed Env conformation. Our data provide insights into the mechanism of HIV entry.
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Thippeshappa R, Kimata JT, Kaushal D. Toward a Macaque Model of HIV-1 Infection: Roadblocks, Progress, and Future Strategies. Front Microbiol 2020; 11:882. [PMID: 32477302 PMCID: PMC7237640 DOI: 10.3389/fmicb.2020.00882] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022] Open
Abstract
The human-specific tropism of Human Immunodeficiency Virus Type 1 (HIV-1) has complicated the development of a macaque model of HIV-1 infection/AIDS that is suitable for preclinical evaluation of vaccines and novel treatment strategies. Several innate retroviral restriction factors, such as APOBEC3 family of proteins, TRIM5α, BST2, and SAMHD1, that prevent HIV-1 replication have been identified in macaque cells. Accessory proteins expressed by Simian Immunodeficiency virus (SIV) such as viral infectivity factor (Vif), viral protein X (Vpx), viral protein R (Vpr), and negative factor (Nef) have been shown to play key roles in overcoming these restriction factors in macaque cells. Thus, substituting HIV-1 accessory genes with those from SIV may enable HIV-1 replication in macaques. We and others have constructed macaque-tropic HIV-1 derivatives [also called simian-tropic HIV-1 (stHIV-1) or Human-Simian Immunodeficiency Virus (HSIV)] carrying SIV vif to overcome APOBEC3 family proteins. Additional modifications to HIV-1 gag in some of the macaque-tropic HIV-1 have also been done to overcome TRIM5α restriction in rhesus and cynomolgus macaques. Although these viruses replicate persistently in macaque species, they do not result in CD4 depletion. Thus, these studies suggest that additional blocks to HIV-1 replication exist in macaques that prevent high-level viral replication. Furthermore, serial animal-to-animal passaging of macaque-tropic HIV-1 in vivo has not resulted in pathogenic variants that cause AIDS in immunocompetent macaques. In this review, we discuss recent developments made toward developing macaque model of HIV-1 infection.
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Affiliation(s)
- Rajesh Thippeshappa
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Jason T Kimata
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Deepak Kaushal
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
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7
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Kmiec D, Nchioua R, Sherrill-Mix S, Stürzel CM, Heusinger E, Braun E, Gondim MVP, Hotter D, Sparrer KMJ, Hahn BH, Sauter D, Kirchhoff F. CpG Frequency in the 5' Third of the env Gene Determines Sensitivity of Primary HIV-1 Strains to the Zinc-Finger Antiviral Protein. mBio 2020; 11:e02903-19. [PMID: 31937644 PMCID: PMC6960287 DOI: 10.1128/mbio.02903-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 11/27/2019] [Indexed: 02/07/2023] Open
Abstract
CpG dinucleotide suppression has been reported to allow HIV-1 to evade inhibition by the zinc-finger antiviral protein (ZAP). Here, we show that primate lentiviruses display marked differences in CpG frequencies across their genome, ranging from 0.44% in simian immunodeficiency virus SIVwrc from Western red colobus to 2.3% in SIVmon infecting mona monkeys. Moreover, functional analyses of a large panel of human and simian immunodeficiency viruses revealed that the magnitude of CpG suppression does not correlate with their susceptibility to ZAP. However, we found that the number of CpG dinucleotides within a region of ∼700 bases at the 5' end of the env gene determines ZAP sensitivity of primary HIV-1 strains but not of HIV-2. Increased numbers of CpGs in this region were associated with reduced env mRNA expression and viral protein production. ZAP sensitivity profiles of chimeric simian-human immunodeficiency viruses (SHIVs) expressing different HIV-1 env genes were highly similar to those of the corresponding HIV-1 strains. The frequency of CpGs in the identified env region correlated with differences in clinical progression rates. Thus, the CpG frequency in a specific part of env, rather than the overall genomic CpG content, governs the susceptibility of HIV-1 to ZAP and might affect viral pathogenicity in vivoIMPORTANCE Evasion of the zinc-finger antiviral protein (ZAP) may drive CpG dinucleotide suppression in HIV-1 and many other viral pathogens but the viral determinants of ZAP sensitivity are poorly defined. Here, we examined CpG suppression and ZAP sensitivity in a large number of primate lentiviruses and demonstrate that their genomic frequency of CpGs varies substantially and does not correlate with ZAP sensitivity. We further show that the number of CpG residues in a defined region at the 5' end of the env gene together with structural features plays a key role in HIV-1 susceptibility to ZAP and correlates with differences in clinical progression rates in HIV-1-infected individuals. Our identification of a specific part of env as a major determinant of HIV-1 susceptibility to ZAP restriction provides a basis for future studies of the underlying inhibitory mechanisms and their potential relevance in the pathogenesis of AIDS.
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Affiliation(s)
- Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Rayhane Nchioua
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Scott Sherrill-Mix
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Elena Heusinger
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Elisabeth Braun
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Marcos V P Gondim
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | | | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
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8
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Buffalo CZ, Stürzel CM, Heusinger E, Kmiec D, Kirchhoff F, Hurley JH, Ren X. Structural Basis for Tetherin Antagonism as a Barrier to Zoonotic Lentiviral Transmission. Cell Host Microbe 2019; 26:359-368.e8. [PMID: 31447307 DOI: 10.1016/j.chom.2019.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/05/2019] [Accepted: 07/31/2019] [Indexed: 12/25/2022]
Abstract
Tetherin is a host defense factor that physically prevents virion release from the plasma membrane. The Nef accessory protein of simian immunodeficiency virus (SIV) engages the clathrin adaptor AP-2 to downregulate tetherin via its DIWK motif. As human tetherin lacks DIWK, antagonism of tetherin by Nef is a barrier to simian-human transmission of non-human primate lentiviruses. To determine the molecular basis for tetherin counteraction, we reconstituted the AP-2 complex with a simian tetherin and SIV Nef and determined its structure by cryoelectron microscopy (cryo-EM). Nef refolds the first α-helix of the β2 subunit of AP-2 to a β hairpin, creating a binding site for the DIWK sequence. The tetherin binding site in Nef is distinct from those of most other Nef substrates, including MHC class I, CD3, and CD4 but overlaps with the site for the restriction factor SERINC5. This structure explains the dependence of SIVs on tetherin DIWK and consequent barrier to human transmission.
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Affiliation(s)
- Cosmo Z Buffalo
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Elena Heusinger
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - James H Hurley
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Xuefeng Ren
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA.
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9
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Abstract
HIV, the causative agent of AIDS, has a complex evolutionary history involving several cross-species transmissions and recombination events as well as changes in the repertoire and function of its accessory genes. Understanding these events and the adaptations to new host species provides key insights into innate defense mechanisms, viral dependencies on cellular factors, and prerequisites for the emergence of the AIDS pandemic. In addition, understanding the factors and adaptations required for the spread of HIV in the human population helps to better assess the risk of future lentiviral zoonoses and provides clues to how improved control of viral replication can be achieved. Here, we summarize our current knowledge on viral features and adaptations preceding the AIDS pandemic. We aim at providing a viral point of view, focusing on known key hurdles of each cross-species transmission and the mechanisms that HIV and its simian precursors evolved to overcome them.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Centre, Ulm 89081, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Centre, Ulm 89081, Germany.
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10
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Kmiec D, Akbil B, Ananth S, Hotter D, Sparrer KMJ, Stürzel CM, Trautz B, Ayouba A, Peeters M, Yao Z, Stagljar I, Passos V, Zillinger T, Goffinet C, Sauter D, Fackler OT, Kirchhoff F. SIVcol Nef counteracts SERINC5 by promoting its proteasomal degradation but does not efficiently enhance HIV-1 replication in human CD4+ T cells and lymphoid tissue. PLoS Pathog 2018; 14:e1007269. [PMID: 30125328 PMCID: PMC6117100 DOI: 10.1371/journal.ppat.1007269] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/30/2018] [Accepted: 08/08/2018] [Indexed: 12/18/2022] Open
Abstract
SERINC5 is a host restriction factor that impairs infectivity of HIV-1 and other primate lentiviruses and is counteracted by the viral accessory protein Nef. However, the importance of SERINC5 antagonism for viral replication and cytopathicity remained unclear. Here, we show that the Nef protein of the highly divergent SIVcol lineage infecting mantled guerezas (Colobus guereza) is a potent antagonist of SERINC5, although it lacks the CD4, CD3 and CD28 down-modulation activities exerted by other primate lentiviral Nefs. In addition, SIVcol Nefs decrease CXCR4 cell surface expression, suppress TCR-induced actin remodeling, and counteract Colobus but not human tetherin. Unlike HIV-1 Nef proteins, SIVcol Nef induces efficient proteasomal degradation of SERINC5 and counteracts orthologs from highly divergent vertebrate species, such as Xenopus frogs and zebrafish. A single Y86F mutation disrupts SERINC5 and tetherin antagonism but not CXCR4 down-modulation by SIVcol Nef, while mutation of a C-proximal di-leucine motif has the opposite effect. Unexpectedly, the Y86F change in SIVcol Nef had little if any effect on viral replication and CD4+ T cell depletion in preactivated human CD4+ T cells and in ex vivo infected lymphoid tissue. However, SIVcol Nef increased virion infectivity up to 10-fold and moderately increased viral replication in resting peripheral blood mononuclear cells (PBMCs) that were first infected with HIV-1 and activated three or six days later. In conclusion, SIVcol Nef lacks several activities that are conserved in other primate lentiviruses and utilizes a distinct proteasome-dependent mechanism to counteract SERINC5. Our finding that evolutionarily distinct SIVcol Nefs show potent anti-SERINC5 activity supports a relevant role of SERINC5 antagonism for viral fitness in vivo. Our results further suggest this Nef function is particularly important for virion infectivity under conditions of limited CD4+ T cell activation. The accessory protein Nef promotes primate lentiviral replication and enhances the pathogenicity of HIV-1 by mechanisms of immune evasion and enhancing viral infectivity and replication. Here, we show that the evolutionarily most isolated primate lentivirus SIVcol lacks several otherwise conserved Nef functions. Nevertheless, SIVcol Nef potently antagonizes SERINC5, a recently discovered inhibitor of viral infectivity, by down-modulating it from the cell surface and inducing its proteasomal degradation. We identified Y86 in SIVcol Nef as a key determinant of SERINC5 antagonism. Efficient counteraction of SERINC5 did not increase HIV-1 replication in preactivated CD4+ T cells and in ex vivo infected lymphoid tissue but had modest enhancing effects when resting PBMCs were first infected and activated six days later. Evolution of high anti-SERINC5 activity by SIVcol Nef supports a relevant role of this antagonism in vivo, for instance by enhancing virion infectivity under conditions of limited T cell activation.
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Affiliation(s)
- Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Bengisu Akbil
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Swetha Ananth
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | | | | | - Birthe Trautz
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Ahidjo Ayouba
- TransVIHMI, Institut de Recherche pour le Développement, University of Montpellier, INSERM, Montpellier, France
| | - Martine Peeters
- TransVIHMI, Institut de Recherche pour le Développement, University of Montpellier, INSERM, Montpellier, France
| | - Zhong Yao
- Donnelly Centre, University of Toronto, Ontario, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Ontario, Canada
- Departments of Biochemistry and Molecular Genetics, University of Toronto, Ontario, Canada
| | - Vânia Passos
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Thomas Zillinger
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | | | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Oliver T. Fackler
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
- * E-mail:
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