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Morath K, Sadhu L, Dyckhoff G, Gapp M, Keppler OT, Fackler OT. Activation-neutral gene editing of tonsillar CD4 T cells for functional studies in human ex vivo tonsil cultures. CELL REPORTS METHODS 2024; 4:100685. [PMID: 38211593 PMCID: PMC10831948 DOI: 10.1016/j.crmeth.2023.100685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/13/2023] [Accepted: 12/13/2023] [Indexed: 01/13/2024]
Abstract
The molecular and immunological properties of tissue-resident resting CD4 T cells are understudied due to the lack of suitable gene editing methods. Here, we describe the ex vivo culture and gene editing methodology ediTONSIL for CD4 T cells from human tonsils. Optimized CRISPR-Cas9 RNP nucleofection results in knockout efficacies of over 90% without requiring exogenous activation. Editing can be performed on multiple cell types in bulk cultures or on isolated CD4 T cells that can be labeled and reintroduced into their tissue environment. Importantly, CD4 T cells maintain their tissue-specific properties such as viability, activation state, or immunocompetence following reassembly into lymphoid aggregates. This highly efficient and versatile gene editing workflow for tonsillar CD4 T cells enables the dissection of molecular mechanisms in ex vivo cultures of human lymphoid tissue and can be adapted to other tonsil-resident cell types.
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Affiliation(s)
- Katharina Morath
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Lopamudra Sadhu
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Gerhard Dyckhoff
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Madeleine Gapp
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Ludwig-Maximilians-Universität München, Pettenkoferstraße 9a, 80336 Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Ludwig-Maximilians-Universität München, Pettenkoferstraße 9a, 80336 Munich, Germany; German Centre for Infection Research (DZIF), Partner Site München, Munich, Germany
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany.
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2
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Pedreño-López S, García E, Guerrero D, Gómez-Mora E, Molina Mateu L, Orera Pérez F, Senserrich J, Clotet B, Cabrera C. Modulation of the autophagic pathway inhibits HIV-1 infection in human lymphoid tissue cultured ex vivo. Sci Rep 2022; 12:7439. [PMID: 35523829 PMCID: PMC9076641 DOI: 10.1038/s41598-022-11181-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/19/2022] [Indexed: 11/09/2022] Open
Abstract
A complex link exists between HIV-1 and autophagy, and discordant results have been reported in different in vitro models regarding the way HIV and autophagy modulate each other. Despite this, there is very limited knowledge about the interplay between HIV and autophagy in vivo in lymphoid tissue, due in part by the lack of cell models that recapitulate the in vivo setting. Here, we evaluate the interrelationship between HIV and autophagy using human ex vivo lymphoid tissue cultures as an HIV infection model. Our results showed that human lymphoid aggregated cultures (HLACs) from tonsillar tissue displayed fully functional autophagic activity. In this system, HIV infection resulted in an increase in autophagy. Notably, we observed that both, autophagy-enhancing (rapamycin) or blocking drugs (3-methyladenine, chloroquine and bafilomycin), were able to decrease HIV-DNA levels and HIV replication. Therefore, efficient HIV-1 replication requires a fine-tuned level of autophagy, so modifications of this balance will have a negative impact on its replication. Therefore, targeting the autophagic pathway could be a new therapeutic approach to be explored to treat HIV-1 infection. Ex vivo cultures of human lymphoid tissue are a suitable model to obtain further insights into HIV and its intricate relationship with autophagy.
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Affiliation(s)
- Sònia Pedreño-López
- grid.7080.f0000 0001 2296 0625AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916 Badalona, Barcelona Spain
| | - Elisabet García
- grid.7080.f0000 0001 2296 0625AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916 Badalona, Barcelona Spain
| | - Dolores Guerrero
- grid.7080.f0000 0001 2296 0625Otorhinolaryngology Department, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - Elisabet Gómez-Mora
- grid.7080.f0000 0001 2296 0625AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916 Badalona, Barcelona Spain
| | - Laura Molina Mateu
- grid.7080.f0000 0001 2296 0625Otorhinolaryngology Department, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - Fernando Orera Pérez
- grid.7080.f0000 0001 2296 0625Otorhinolaryngology Department, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - Jordi Senserrich
- grid.7080.f0000 0001 2296 0625AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916 Badalona, Barcelona Spain
| | - Bonaventura Clotet
- grid.7080.f0000 0001 2296 0625AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916 Badalona, Barcelona Spain ,grid.411438.b0000 0004 1767 6330Infectious Diseases Department, Hospital Germans Trias i Pujol, Badalona, Catalonia Spain ,grid.440820.aUniversitat de Vic Central de Catalunya, Vic, Catalonia Spain
| | - Cecilia Cabrera
- AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet S/N, 08916, Badalona, Barcelona, Spain.
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3
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Schmidt A, Baumjohann D. 3D Tissue Explant and Single-Cell Suspension Organoid Culture Systems for Ex Vivo Drug Testing on Human Tonsil-Derived T Follicular Helper Cells. Methods Mol Biol 2022; 2380:267-288. [PMID: 34802138 DOI: 10.1007/978-1-0716-1736-6_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Research on the human immune system is often restricted to peripheral blood cells. However, these cells can be different from those found in secondary lymphoid organs. For instance, specialized T and B cells that are localized in germinal centers (GCs), which are complex anatomical structures being required for the generation of potent antibodies, are not found in peripheral blood. Most T helper cells located in GCs belong to the T follicular helper (Tfh) cell subset, which provides critical support to B cells. Bona fide human GC Tfh cells can be obtained from secondary lymphoid tissues such as tonsils, which are routinely removed by surgery. We here describe a method that is based on human lymphoid histoculture (HLH) and human lymphoid aggregate culture (HLAC) to culture human adenoid (pharyngeal tonsil) tissue ex vivo, followed by deep Tfh cell phenotyping by flow cytometry. This method allows studying Tfh cells in a versatile explant culture system that preserves many aspects of the original in vivo three-dimensional (3D) structure, in parallel to single-cell suspension organoid cultures in which the original tissue structure is disintegrated. We also describe how this versatile platform can be used for drug testing or manipulation of human Tfh cells in vitro for mechanistic studies.
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Affiliation(s)
- Angelika Schmidt
- Institute for Immunology, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, Martinsried, Germany
| | - Dirk Baumjohann
- Institute for Immunology, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, Martinsried, Germany.
- Medical Clinic III for Oncology, Hematology, Immuno-Oncology and Rheumatology, University Hospital Bonn, University of Bonn, Bonn, Germany.
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4
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Biswas A, Zhou D, Fiches GN, Wu Z, Liu X, Ma Q, Zhao W, Zhu J, Santoso NG. Inhibition of polo-like kinase 1 (PLK1) facilitates reactivation of gamma-herpesviruses and their elimination. PLoS Pathog 2021; 17:e1009764. [PMID: 34297745 PMCID: PMC8336821 DOI: 10.1371/journal.ppat.1009764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 08/04/2021] [Accepted: 06/29/2021] [Indexed: 01/06/2023] Open
Abstract
Both Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) establish the persistent, life-long infection primarily at the latent status, and associate with certain types of tumors, such as B cell lymphomas, especially in immuno-compromised individuals including people living with HIV (PLWH). Lytic reactivation of these viruses can be employed to kill tumor cells harboring latently infected viral episomes through the viral cytopathic effects and the subsequent antiviral immune responses. In this study, we identified that polo-like kinase 1 (PLK1) is induced by KSHV de novo infection as well as lytic switch from KSHV latency. We further demonstrated that PLK1 depletion or inhibition facilitates KSHV reactivation and promotes cell death of KSHV-infected lymphoma cells. Mechanistically, PLK1 regulates Myc that is critical to both maintenance of KSHV latency and support of cell survival, and preferentially affects the level of H3K27me3 inactive mark both globally and at certain loci of KSHV viral episomes. Furthremore, we recognized that PLK1 inhibition synergizes with STAT3 inhibition to efficiently induce KSHV reactivation. We also confirmed that PLK1 depletion or inhibition yields the similar effect on EBV lytic reactivation and cell death of EBV-infected lymphoma cells. Lastly, we noticed that PLK1 in B cells is elevated in the context of HIV infection and caused by HIV Nef protein to favor KSHV/EBV latency.
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Affiliation(s)
- Ayan Biswas
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
- Department of Genetics, School of Medicine, Unversity of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Dawei Zhou
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Guillaume N. Fiches
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Zhenyu Wu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
- Department of Biomedical Informatics, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Xuefeng Liu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, D.C., United States of America
| | - Qin Ma
- Department of Biomedical Informatics, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Weiqiang Zhao
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Jian Zhu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Netty G. Santoso
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
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5
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Reif T, Dyckhoff G, Hohenberger R, Kolbe CC, Gruell H, Klein F, Latz E, Stolp B, Fackler OT. Contact-dependent inhibition of HIV-1 replication in ex vivo human tonsil cultures by polymorphonuclear neutrophils. CELL REPORTS MEDICINE 2021; 2:100317. [PMID: 34195682 PMCID: PMC8233696 DOI: 10.1016/j.xcrm.2021.100317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/02/2021] [Accepted: 05/20/2021] [Indexed: 12/01/2022]
Abstract
Polymorphonuclear neutrophils (PMNs), the most abundant white blood cells, are recruited rapidly to sites of infection to exert potent anti-microbial activity. Information regarding their role in infection with human immunodeficiency virus (HIV) is limited. Here we report that addition of PMNs to HIV-infected cultures of human tonsil tissue or peripheral blood mononuclear cells causes immediate and long-lasting suppression of HIV-1 spread and virus-induced depletion of CD4 T cells. This inhibition of HIV-1 spread strictly requires PMN contact with infected cells and is not mediated by soluble factors. 2-Photon (2PM) imaging visualized contacts of PMNs with HIV-1-infected CD4 T cells in tonsil tissue that do not result in lysis or uptake of infected cells. The anti-HIV activity of PMNs also does not involve degranulation, formation of neutrophil extracellular traps, or integrin-dependent cell communication. These results reveal that PMNs efficiently blunt HIV-1 replication in primary target cells and tissue by an unconventional mechanism. PMNs blunt HIV-1 spread and CD4 T cell depletion in HIV-infected human tonsils Suppression of HIV-1 replication by PMNs requires cell-cell contacts PMNs do not affect HIV via effector functions such as NETosis or degranulation PMNs exert unconventional antiviral activity
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Affiliation(s)
- Tatjana Reif
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Gerhard Dyckhoff
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Ralph Hohenberger
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Carl-Christian Kolbe
- Institute of Innate Immunity, Department of Innate Immunity and Metaflammation, University Hospital Bonn, 53127 Bonn, Germany
| | - Henning Gruell
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50931 Cologne, Germany
| | - Florian Klein
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, 50931 Cologne, Germany
| | - Eicke Latz
- Institute of Innate Immunity, Department of Innate Immunity and Metaflammation, University Hospital Bonn, 53127 Bonn, Germany
| | - Bettina Stolp
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.,German Center for Infection Research (DZIF), Partner Site Heidelberg, 69120 Heidelberg, Germany
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6
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Kruize Z, van Nuenen AC, van Wijk SW, Girigorie AF, van Dort KA, Booiman T, Kootstra NA. Nef Obtained from Individuals with HIV-1 Vary in Their Ability to Antagonize SERINC3- and SERINC5-Mediated HIV-1 Restriction. Viruses 2021; 13:v13030423. [PMID: 33800773 PMCID: PMC8000780 DOI: 10.3390/v13030423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/25/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
Nef is a multifunctional viral protein that has the ability to downregulate cell surface molecules, including CD4 and major histocompatibility complex class I (MHC-I) and, as recently shown, also members of the serine incorporator family (SERINC). Here, we analyzed the impact of naturally occurring mutations in HIV-1 Nef on its ability to counteract SERINC restriction and the clinical course of infection. HIV-1 Nef sequences were obtained from 123 participants of the Amsterdam Cohort Studies and showed multiple amino acid variations and mutations. Most of the primary Nef proteins showed increased activity to counteract SERINC3 and SERINC5 as compared to NL4-3 Nef. Several mutations in Nef were associated with either an increased or decreased infectivity of Bal26-pseudotyped HIV-1 produced in the presence of SERINC3 or SERINC5. The 8R, 157N and R178G Nef mutations were shown to have an effect on disease progression. Survival analysis showed an accelerated disease progression of individuals infected with HIV-1 carrying arginine or asparagine at position 8 or 157 in Nef, respectively, or the R178G Nef mutation. Here, we observed that naturally occurring mutations in Nef affect the ability of Nef to counteract SERINC3- and SERINC5-mediated inhibition of viral infectivity. The majority of these Nef mutations had no significant effect on HIV-1 pathogenesis and only the 8R, 157N and R178G mutations were associated with disease course.
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7
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Kaw S, Ananth S, Tsopoulidis N, Morath K, Coban BM, Hohenberger R, Bulut OC, Klein F, Stolp B, Fackler OT. HIV-1 infection of CD4 T cells impairs antigen-specific B cell function. EMBO J 2020; 39:e105594. [PMID: 33146906 PMCID: PMC7737609 DOI: 10.15252/embj.2020105594] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
Failures to produce neutralizing antibodies upon HIV‐1 infection result in part from B‐cell dysfunction due to unspecific B‐cell activation. How HIV‐1 affects antigen‐specific B‐cell functions remains elusive. Using an adoptive transfer mouse model and ex vivo HIV infection of human tonsil tissue, we found that expression of the HIV‐1 pathogenesis factor NEF in CD4 T cells undermines their helper function and impairs cognate B‐cell functions including mounting of efficient specific IgG responses. NEF interfered with T cell help via a specific protein interaction motif that prevents polarized cytokine secretion at the T‐cell–B‐cell immune synapse. This interference reduced B‐cell activation and proliferation and thus disrupted germinal center formation and affinity maturation. These results identify NEF as a key component for HIV‐mediated dysfunction of antigen‐specific B cells. Therapeutic targeting of the identified molecular surface in NEF will facilitate host control of HIV infection.
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Affiliation(s)
- Sheetal Kaw
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Swetha Ananth
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Nikolaos Tsopoulidis
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Katharina Morath
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Bahar M Coban
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Ralph Hohenberger
- Department of Otorhinolaryngology, University Hospital Heidelberg, Heidelberg, Germany
| | - Olcay C Bulut
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany.,Department of Otorhinolaryngology, Head and Neck Surgery, SLK Klinikum Am Gesundbrunnen, Heilbronn, Germany
| | - Florian Klein
- Laboratory of Experimental Immunology, Institute of Virology, University Hospital of Cologne, Cologne, Germany.,German Centre for Infection Research (DZIF), Partner Site Köln, Köln, Germany
| | - Bettina Stolp
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
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8
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Schmidt A, Huber JE, Sercan Alp Ö, Gürkov R, Reichel CA, Herrmann M, Keppler OT, Leeuw T, Baumjohann D. Complex human adenoid tissue-based ex vivo culture systems reveal anti-inflammatory drug effects on germinal center T and B cells. EBioMedicine 2020; 53:102684. [PMID: 32114393 PMCID: PMC7049648 DOI: 10.1016/j.ebiom.2020.102684] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Human immunology research is often limited to peripheral blood. However, there are important differences between blood immune cells and their counterparts residing in secondary lymphoid organs, such as in the case of germinal center (GC) T follicular helper (Tfh) cells and GC B cells. METHODS We developed a versatile ex vivo lymphoid organ culture platform that is based on human pharyngeal tonsils (adenoids) and allows for drug testing. We systematically phenotyped Tfh and GC B cell subsets in explant- and suspension cultures using multicolor flow cytometry and cytokine multiplex analysis. FINDINGS Phenotypic changes of certain ex vivo cultured immune cell subsets could be modulated by cytokine addition. Furthermore, we optimized an activation-induced marker assay to evaluate the response to T cell stimulation. We provide proof-of-concept that Tfh and GC B cells could be modulated in these cultures by different anti-inflammatory drugs in unstimulated states and upon activation with vaccine-derived antigens. For example, GC B cells were lost upon CD40L blockade, and clinically approved JAK inhibitors impacted Tfh and GC B cells, including down-regulation of their key transcription factor BCL6. BCL6 regulation was affected by IL-6 signaling in T cells and IL-4 in B cells, respectively. Furthermore, we demonstrated that JAK signaling and TNF signaling contributed to the stimulation-induced activation of tonsil-derived T cells. INTERPRETATION Our optimized methods, assays, and mechanistic findings can contribute to a better understanding of human GC responses. These insights may be relevant for improving autoimmune disease therapy and vaccination efficacy. FUNDING This work was supported by a project grant under the joint research cooperation agreement of LMU Munich, LMU University Hospital, and Sanofi-Aventis Deutschland GmbH, as well as by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Emmy Noether Programme BA 5132/1-1 and BA 5132/1-2 (252623821), SFB 1054 Project B12 (210592381), and SFB 914 Project B03 (165054336).
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Affiliation(s)
- Angelika Schmidt
- Institute for Immunology, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany.
| | - Johanna E Huber
- Institute for Immunology, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Özen Sercan Alp
- R&D, TA Immunology & Inflammation Research, Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, 65926 Frankfurt am Main, Germany
| | - Robert Gürkov
- Department of Otorhinolaryngology, University Hospital, LMU Munich, 81377 Munich, Germany
| | - Christoph A Reichel
- Department of Otorhinolaryngology, University Hospital, LMU Munich, 81377 Munich, Germany; Walter Brendel Centre of Experimental Medicine, University Hospital, LMU Munich, 81377 Munich, Germany
| | - Matthias Herrmann
- R&D, TA Immunology & Inflammation Research, Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, 65926 Frankfurt am Main, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
| | - Thomas Leeuw
- R&D, TA Immunology & Inflammation Research, Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, 65926 Frankfurt am Main, Germany
| | - Dirk Baumjohann
- Institute for Immunology, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany; Medical Clinic III for Oncology, Hematology, Immuno-Oncology and Rheumatology, University Hospital Bonn, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
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9
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Łyszkiewicz M, Ziętara N, Frey L, Pannicke U, Stern M, Liu Y, Fan Y, Puchałka J, Hollizeck S, Somekh I, Rohlfs M, Yilmaz T, Ünal E, Karakukcu M, Patiroğlu T, Kellerer C, Karasu E, Sykora KW, Lev A, Simon A, Somech R, Roesler J, Hoenig M, Keppler OT, Schwarz K, Klein C. Human FCHO1 deficiency reveals role for clathrin-mediated endocytosis in development and function of T cells. Nat Commun 2020; 11:1031. [PMID: 32098969 PMCID: PMC7042371 DOI: 10.1038/s41467-020-14809-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/23/2020] [Indexed: 01/05/2023] Open
Abstract
Clathrin-mediated endocytosis (CME) is critical for internalisation of molecules across cell membranes. The FCH domain only 1 (FCHO1) protein is key molecule involved in the early stages of CME formation. The consequences of mutations in FCHO1 in humans were unknown. We identify ten unrelated patients with variable T and B cell lymphopenia, who are homozygous for six distinct mutations in FCHO1. We demonstrate that these mutations either lead to mislocalisation of the protein or prevent its interaction with binding partners. Live-cell imaging of cells expressing mutant variants of FCHO1 provide evidence of impaired formation of clathrin coated pits (CCP). Patient T cells are unresponsive to T cell receptor (TCR) triggering. Internalisation of the TCR receptor is severely perturbed in FCHO1-deficient Jurkat T cells but can be rescued by expression of wild-type FCHO1. Thus, we discovered a previously unrecognised critical role of FCHO1 and CME during T-cell development and function in humans.
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Affiliation(s)
- Marcin Łyszkiewicz
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany.
- Institute for Immunology, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martinsried, 82152, Munich, Germany.
| | - Natalia Ziętara
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
- Institute for Immunology, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martinsried, 82152, Munich, Germany
| | - Laura Frey
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Ulrich Pannicke
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Marcel Stern
- Max von Pettenkofer Institute, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
| | - Yanshan Liu
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Yanxin Fan
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Jacek Puchałka
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Sebastian Hollizeck
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Ido Somekh
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Meino Rohlfs
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Tuğba Yilmaz
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Ekrem Ünal
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Musa Karakukcu
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Türkan Patiroğlu
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
- Department of Pediatrics, Division of Pediatric Immunology, Erciyes University, Kayseri, Turkey
| | | | - Ebru Karasu
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Karl-Walter Sykora
- Department of Pediatric Hematology/Oncology, Hannover Medical School, Hannover, Germany
| | - Atar Lev
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Amos Simon
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Raz Somech
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Joachim Roesler
- Department of Pediatrics, Carl Gustav Carus Technical University Dresden, Dresden, Germany
| | - Manfred Hoenig
- Department of Pediatrics, University Medical Centre Ulm, Ulm, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Klaus Schwarz
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
- Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg, Hessen, Germany
| | - Christoph Klein
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany.
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Multifunctional Roles of the N-Terminal Region of HIV-1 SF2Nef Are Mediated by Three Independent Protein Interaction Sites. J Virol 2019; 94:JVI.01398-19. [PMID: 31597760 DOI: 10.1128/jvi.01398-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 01/23/2023] Open
Abstract
HIV-1 Nef promotes virus spread and disease progression by altering host cell transport and signaling processes through interaction with multiple host cell proteins. The N-terminal region in HIV-1 Nef encompassing residues 12 to 39 has been implicated in many Nef activities, including disruption of CD4 T lymphocyte polarization and homing to lymph nodes, antagonism of SERINC5 restriction to virion infectivity, downregulation of cell surface CD4 and major histocompatibility complex class I (MHC-I), release of Nef-containing extracellular vesicles, and phosphorylation of Nef by recruitment of the Nef-associated kinase complex (NAKC). How this region mediates these pleiotropic functions is unclear. Characterization of a panel of alanine mutants spanning the N-terminal region to identify specific functional determinants revealed this region to be dispensable for effects of Nef from HIV-1 strain SF2 (HIV-1SF2Nef) on T cell actin organization and chemotaxis, retargeting of the host cell kinase Lck to the trans-Golgi network, and incorporation of Nef into extracellular vesicles. MHC-I downmodulation was specific to residue M20, and inhibition of T cell polarization by Nef required the integrity of the entire region. In contrast, downmodulation of cell surface CD4 and SERINC5 antagonism were mediated by a specific motif encompassing residues 32 to 39 that was also essential for efficient HIV replication in primary CD4 T lymphocytes. Finally, Nef phosphorylation via association with the NAKC was mediated by two EP repeats within residues 24 to 29 but was dispensable for other functions. These results identify the N-terminal region as a multifunctional interaction module for at least three different host cell ligands that mediate independent functions of HIV-1SF2Nef to facilitate immune evasion and virus spread.IMPORTANCE HIV-1 Nef critically determines virus spread and disease progression in infected individuals by acting as a protein interaction adaptor via incompletely defined mechanisms and ligands. Residues 12 to 39 near the N terminus of Nef have been described as an interaction platform for the Nef-associated kinase complex (NAKC) and were recently identified as essential determinants for a broad range of Nef activities. Here, we report a systematic mapping of this amino acid stretch that revealed the presence of three independent interaction motifs with specific ligands and activities. While downmodulation of cell surface MHC-I depends on M20, two EP repeats are the minimal binding site for the NAKC, and residues 32 to 39 mediate antagonism of the host cell restriction factor SERINC5 as well as downmodulation of cell surface CD4. These results reveal that the N-terminal region of HIV-1SF2Nef is a versatile and multifunctional protein interaction module that exerts essential functions of the pathogenicity factor via independent mechanisms.
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Lamas-Murua M, Stolp B, Kaw S, Thoma J, Tsopoulidis N, Trautz B, Ambiel I, Reif T, Arora S, Imle A, Tibroni N, Wu J, Cui G, Stein JV, Tanaka M, Lyck R, Fackler OT. HIV-1 Nef Disrupts CD4 + T Lymphocyte Polarity, Extravasation, and Homing to Lymph Nodes via Its Nef-Associated Kinase Complex Interface. THE JOURNAL OF IMMUNOLOGY 2018; 201:2731-2743. [PMID: 30257886 DOI: 10.4049/jimmunol.1701420] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 08/21/2018] [Indexed: 12/31/2022]
Abstract
HIV-1 Nef is a multifunctional protein that optimizes virus spread and promotes immune evasion of infected cells to accelerate disease progression in AIDS patients. As one of its activities, Nef reduces the motility of infected CD4+ T lymphocytes in confined space. In vivo, Nef restricts T lymphocyte homing to lymph nodes as it reduces the ability for extravasation at the diapedesis step. Effects of Nef on T lymphocyte motility are typically mediated by its ability to reduce actin remodeling. However, interference with diapedesis does not depend on residues in Nef required for inhibition of host cell actin dynamics. In search for an alternative mechanism by which Nef could alter T lymphocyte extravasation, we noted that the viral protein interferes with the polarization of primary human CD4+ T lymphocytes upon infection with HIV-1. Expression of Nef alone is sufficient to disrupt T cell polarization, and this effect is conserved among lentiviral Nef proteins. Nef acts by arresting the oscillation of CD4+ T cells between polarized and nonpolarized morphologies. Mapping studies identified the binding site for the Nef-associated kinase complex (NAKC) as critical determinant of this Nef activity and a NAKC-binding-deficient Nef variant fails to impair CD4+ T lymphocyte extravasation and homing to lymph nodes. These results thus imply the disruption of T lymphocyte polarity via its NAKC binding site as a novel mechanism by which lentiviral Nef proteins alter T lymphocyte migration in vivo.
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Affiliation(s)
- Miguel Lamas-Murua
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Bettina Stolp
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Sheetal Kaw
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Judith Thoma
- Physical Chemistry of Biosystems, University of Heidelberg, 69120 Heidelberg, Germany
| | - Nikolaos Tsopoulidis
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Birthe Trautz
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Ina Ambiel
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Tatjana Reif
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Sakshi Arora
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Andrea Imle
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Nadine Tibroni
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jingxia Wu
- T Cell Metabolism (D140), German Cancer Research Centre, 69120 Heidelberg, Germany
| | - Guoliang Cui
- T Cell Metabolism (D140), German Cancer Research Centre, 69120 Heidelberg, Germany
| | - Jens V Stein
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland; and
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, University of Heidelberg, 69120 Heidelberg, Germany.,Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Ruth Lyck
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland; and
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
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12
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Cho YK, Kim JE, Lee SH, Foley BT, Choi BS. Impact of HIV-1 subtype and Korean Red Ginseng on AIDS progression: comparison of subtype B and subtype D. J Ginseng Res 2018; 43:312-318. [PMID: 30976169 PMCID: PMC6437552 DOI: 10.1016/j.jgr.2018.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/11/2018] [Accepted: 07/16/2018] [Indexed: 11/18/2022] Open
Abstract
Background To date, no study has described disease progression in Asian patients infected with HIV-1 subtype D. Methods To determine whether the disease progression differs in patients infected with subtypes D and B prior to starting combination antiretroviral therapy, the annual decline (AD) in CD4+ T cell counts over 96 ± 59 months was retrospectively analyzed in 163 patients and compared in subtypes D and B based on the nef gene. Results CD4+ T cell AD was significantly higher in the six subtype D–infected patients than in the 157 subtype B–infected patients irrespective of Korean Red Ginseng (KRG) treatment (p < 0.001). Of these, two subtype D–infected patients and 116 subtype B–infected patients had taken KRG. AD was significantly lower in patient in the KRG-treated group than in those in the KRG-naïve group irrespective of subtype (p < 0.05). To control for the effect of KRG, patients not treated with KRG were analyzed, with AD found to be significantly greater in subtype D–infected patients than in subtype B–infected patients (p < 0.01). KRG treatment had a greater effect on AD in subtype D–infected patients than in subtype B–infected patients (4.5-fold vs. 1.6-fold). Mortality rates were significantly higher in both the 45 KRG-naïve (p < 0.001) and all 163 (p < 0.01) patients infected with subtype D than subtype B. Conclusion Subtype D infection is associated with a >2-fold higher risk of death and a 2.9-fold greater rate of progression than subtype B, regardless of KRG treatment.
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Affiliation(s)
- Young-Keol Cho
- Department of Microbiology, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Corresponding author. Department of Microbiology, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.
| | - Jung-Eun Kim
- Department of Microbiology, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sun-Hee Lee
- Division of Infectious Diseases, Department of Internal Medicine, Pusan National University Hospital, Busan, Republic of Korea
| | - Brian T. Foley
- HIV Databases, Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Byeong-Sun Choi
- Division of AIDS, Center for Immunology and Pathology, Korea National Institute of Health, Chung-buk, Republic of Korea
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13
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Wang G, Wang Z, Zhuang P, Zhao X, Cheng Z. Exosomes carring gag/env of ALV-J possess negative effect on immunocytes. Microb Pathog 2017; 112:142-147. [PMID: 28916320 DOI: 10.1016/j.micpath.2017.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/04/2017] [Accepted: 09/11/2017] [Indexed: 01/21/2023]
Abstract
J subgroup avian leukosis virus (ALV-J) is an exogenous retrovirus of avian. A key feature of ALV-J infection is leading to severe immunosuppressive characteristic of diseases. Viral components of retrovirus were reported closely associated with immunosuppression, and several similarities between exosomes and retrovirus preparations have lead to the hypotheses of retrovirus hijacker exosomes pathway. In this study, we purified exosomes from DF-1 cells infected and uninfected by ALV-J. Electron microscopy and mass spectrometry (MS) analysis showed that ALV-J not only increased the production of exosomes from ALV-J infected DF-1 cells (Exo-J) but also stimulated some proteins expression, especially ALV-J components secreted in exosomes. Immunosuppressive domain peptide (ISD) of envelope subunit transmembrane (TM) and gag of ALV-J were secreted in Exo-J. It has been reported that HIV gag was budded from endosome-like domains of the T cell plasma membrane. But env protein was first detected in exosomes from retrovirus infected cells. We found that Exo-J caused negative effects on splenocytes in a dose-dependant manner by flow cytometric analysis. And low dose of Exo-J activated immune activity of splenocytes, while high dose possessed immunosuppressive properties. Interestingly, Exo-J has no significant effects on the immunosuppression induced by ALV-J, and the immunosuppressive effects induced by Exo-J lower than that by ALV-J. Taken together, our data indicated that Exo-J supplied a microenvironment for the replication and transformation of ALV-J.
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Affiliation(s)
- Guihua Wang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, PR China
| | - Zhenzhen Wang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China
| | - Pingping Zhuang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China
| | - Xiaomin Zhao
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, PR China
| | - Ziqiang Cheng
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, PR China.
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Spotlight on HIV-1 Nef: SERINC3 and SERINC5 Identified as Restriction Factors Antagonized by the Pathogenesis Factor. Viruses 2015; 7:6730-8. [PMID: 26703715 PMCID: PMC4690893 DOI: 10.3390/v7122970] [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: 10/27/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022] Open
Abstract
The Nef protein is an accessory gene product encoded by human immunodeficiency virus types 1 and 2 (HIV-1/-2) and simian immunodeficiency virus (SIV) that boosts virus replication in the infected host and accelerates disease progression. Unlike the HIV-1 accessory proteins Vif, Vpr and Vpu, Nef was, until recently, not known to antagonize the antiviral activity of a host cell restriction factor. Two recent reports now describe the host cell proteins serine incorporator 3 and 5 (SERINC3 and SERINC5) as potent inhibitors of HIV-1 particle infectivity and demonstrate that Nef counteracts these effects. These findings establish SERINC3/5 as restrictions to HIV replication in human cells and define a novel activity for the HIV pathogenesis factor Nef.
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15
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Watkins RL, Foster JL, Garcia JV. In vivo analysis of Nef's role in HIV-1 replication, systemic T cell activation and CD4(+) T cell loss. Retrovirology 2015; 12:61. [PMID: 26169178 PMCID: PMC4501112 DOI: 10.1186/s12977-015-0187-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/29/2015] [Indexed: 11/21/2022] Open
Abstract
Background Nef is a multifunctional HIV-1 protein critical for progression to AIDS. Humans infected with nef(−) HIV-1 have greatly delayed or no disease consequences. We have contrasted nef(−) and nef(+) infection of BLT humanized mice to better characterize Nef’s pathogenic effects. Results Mice were inoculated with CCR5-tropic HIV-1JRCSF (JRCSF) or JRCSF with an irreversibly inactivated nef (JRCSFNefdd). In peripheral blood (PB), JRCSF exhibited high levels of viral RNA (peak viral loads of 4.71 × 106 ± 1.23 × 106 copies/ml) and a progressive, 75% loss of CD4+ T cells over 17 weeks. Similar losses were observed in CD4+ T cells from bone marrow, spleen, lymph node, lung and liver but thymocytes were not significantly decreased. JRCSFNefdd also had high peak viral loads (2.31 × 106 ± 1.67 × 106) but induced no loss of PB CD4+ T cells. In organs, JRCSFNefdd produced small, but significant, reductions in CD4+ T cell levels and did not affect the level of thymocytes. Uninfected mice have low levels of HLA-DR+CD38+CD8+ T cells in blood (1–2%). Six weeks post inoculation, JRCSF infection resulted in significantly elevated levels of activated CD8+ T cells (6.37 ± 1.07%). T cell activation coincided with PB CD4+ T cell loss which suggests a common Nef-dependent mechanism. At 12 weeks, in JRCSF infected animals PB T cell activation sharply increased to 19.7 ± 2.9% then subsided to 5.4 ± 1.4% at 14 weeks. HLA-DR+CD38+CD8+ T cell levels in JRCSFNefdd infected mice did not rise above 1–2% despite sustained high levels of viremia. Interestingly, we also noted that in mice engrafted with human tissue expressing a putative protective HLA-B allele (B42:01), JRCSFNefdd exhibited a substantial (200-fold) reduced viral load compared to JRCSF. Conclusions Nef expression was necessary for both systemic T cell activation and substantial CD4+ T cell loss from blood and tissues. JRCSFNefdd infection did not activate CD8+ T cells or reduce the level of CD4+ T cells in blood but did result in a small Nef-independent decrease in CD4+ T cells in organs. These observations strongly support the conclusion that viral pathogenicity is mostly driven by Nef. We also observed for the first time substantial host-specific suppression of HIV-1 replication in a small animal infection model. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0187-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Richard L Watkins
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
| | - John L Foster
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
| | - J Victor Garcia
- Division of Infectious Diseases, UNC Center for AIDS Research, Genetic Medicine, University of North Carolina, Campus Box 7042, Chapel Hill, NC, 27599-7042, USA.
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16
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Adding new dimensions: towards an integrative understanding of HIV-1 spread. Nat Rev Microbiol 2014; 12:563-74. [PMID: 25029025 DOI: 10.1038/nrmicro3309] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In vitro studies in primary or immortalized cells continue to be used to elucidate the essential principles that govern the interactions between HIV-1 and isolated target cells. However, until recently, substantial technical barriers prevented this information from being efficiently translated to the more complex scenario of HIV-1 spread in the host in vivo, which has limited our understanding of the impact of host physiological parameters on the spread of HIV-1. In this Review, we discuss the recent development of imaging approaches to visualize HIV-1 spread and the adaptation of these approaches to organotypic ex vivo models and animal models. We focus on new concepts, including the mechanisms and in vivo relevance of cell-cell transmission for HIV-1 spread and the function of the HIV-1 pathogenesis factor Nef, which have emerged from the application of these integrative approaches in complex cell systems.
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Pan X, Baldauf HM, Keppler OT, Fackler OT. Restrictions to HIV-1 replication in resting CD4+ T lymphocytes. Cell Res 2013; 23:876-85. [PMID: 23732522 PMCID: PMC3698640 DOI: 10.1038/cr.2013.74] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
CD4+ T lymphocytes represent the main target cell population of human immunodeficiency virus (HIV). In an activated state, CD4+ T cells residing in lymphoid organs are a major reservoir of ongoing HIV-1 replication in infected individuals. In contrast, resting CD4+ T cells are highly resistant to productive HIV-1 infection, yet are massively depleted during disease progression and represent a substantial latent reservoir for the virus in vivo. Barriers preventing replication of HIV-1 in resting CD4+ T cells include a rigid layer of cortical actin and, early after HIV-1 entry, a block that limits reverse transcription of incoming viral RNA genomes. Defining the molecular bases of these restrictions has remained one of the central open questions in HIV research. Recent advances unraveled mechanisms by which HIV-1 bypasses the entry block and established the host cell restriction factor SAMHD1, a deoxynucleoside triphosphate triphosphohydrolase, as a central determinant of the cellular restriction to HIV-1 reverse transcription in resting CD4+ T cells. This review summarizes our current molecular and pathophysiological understanding of the multi-faceted interactions of HIV-1 with resting CD4+ T lymphocytes.
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Affiliation(s)
- Xiaoyu Pan
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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18
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Abraham L, Fackler OT. HIV-1 Nef: a multifaceted modulator of T cell receptor signaling. Cell Commun Signal 2012; 10:39. [PMID: 23227982 PMCID: PMC3534016 DOI: 10.1186/1478-811x-10-39] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 11/28/2012] [Indexed: 12/26/2022] Open
Abstract
Nef, an accessory protein of the Human Immunodeficiency Virus type 1 (HIV-1), is dispensable for viral replication in cell culture, but promotes virus replication and pathogenesis in the infected host. Acting as protein-interaction adaptor, HIV-1 Nef modulates numerous target cell activities including cell surface receptor expression, cytoskeletal remodeling, vesicular transport, and signal transduction. In infected T-lymphocytes, altering T-cell antigen receptor (TCR) signaling has long been recognized as one key function of the viral protein. However, reported effects of Nef range from inhibition to activation of this cascade. Recent advances in the field begin to explain these seemingly contradictory observations and suggest that Nef alters intracellular trafficking of TCR proximal machinery to disrupt plasma membrane bound TCR signaling while at the same time, the viral protein induces localized signal transduction at the trans-Golgi network. This review summarizes these new findings on how HIV-1 Nef reprograms TCR signalling output from a broad response to selective activation of the RAS-Erk pathway. We also discuss the implications of these alterations in the context of HIV-1 infection and in light of current concepts of TCR signal transduction.
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Affiliation(s)
- Libin Abraham
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, INF 324, Heidelberg, 69120, Germany.
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19
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Zou W, Denton PW, Watkins RL, Krisko JF, Nochi T, Foster JL, Garcia JV. Nef functions in BLT mice to enhance HIV-1 replication and deplete CD4+CD8+ thymocytes. Retrovirology 2012; 9:44. [PMID: 22640559 PMCID: PMC3403983 DOI: 10.1186/1742-4690-9-44] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Accepted: 05/28/2012] [Indexed: 02/05/2023] Open
Abstract
Background The outcome of untreated HIV-1 infection is progression to AIDS and death in nearly all cases. Some important exceptions are the small number of patients infected with HIV-1 deleted for the accessory gene, nef. With these infections, disease progression is entirely suppressed or greatly delayed. Whether Nef is critical for high levels of replication or is directly cytotoxic remains controversial. The major problem in determining the role of Nef in HIV/AIDS has been the lack of tractable in vivo models where Nef’s complex pathogenic phenotype can be recapitulated. Results Intravenous inoculation (3000 to 600,000 TCIU) of BLT humanized mice with HIV-1LAI reproducibly establishes a systemic infection. HIV-1LAI (LAI) replicates to high levels (peak viral load in blood 8,200,000 ± 1,800,000 copies of viral RNA/ml, range 3,600,000 to 20,400,000; n = 9) and exhaustively depletes CD4+ T cells in blood and tissues. CD4+CD8+ thymocytes were also efficiently depleted but CD4+CD8- thymocytes were partially resistant to cell killing by LAI. Infection with a nef-deleted LAI (LAINefdd) gave lower peak viral loads (1,220,000 ± 330,000, range 27,000 to 4,240,000; n = 17). For fourteen of seventeen LAINefdd-infected mice, there was little to no loss of either CD4+ T cells or thymocytes. Both LAI- and LAINefdd-infected mice had about 8% of total peripheral blood CD8+ T cells that were CD38+HLA-DR+ compared <1% for uninfected mice. Three exceptional LAINefdd-infected mice that lost CD4+ T cells received 600,000 TCIU. All three exhibited peak viral loads over 3,000,000 copies of LAINefdd RNA/ml. Over an extended time course, substantial systemic CD4+ T cell loss was observed for the three mice, but there was no loss of CD4+CD8+ or CD4+CD8- thymocytes. Conclusion We conclude Nef is necessary for elevated viral replication and as a result indirectly contributes to CD4+ T cell killing. Further, Nef was not necessary for the activation of peripheral blood CD8+ T cells following infection. However, CD4+CD8+ thymocyte killing was dependent on Nef even in cases of elevated LAINefdd replication and T cell loss. This depletion of thymic T cell precursors may be a significant factor in the elevated pathogenicity of CXCR4 trophic HIV-1.
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Affiliation(s)
- Wei Zou
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, NC 27599-7042, USA
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20
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Meuwissen PJ, Stolp B, Iannucci V, Vermeire J, Naessens E, Saksela K, Geyer M, Vanham G, Arien KK, Fackler OT, Verhasselt B. Identification of a highly conserved valine-glycine-phenylalanine amino acid triplet required for HIV-1 Nef function. Retrovirology 2012; 9:34. [PMID: 22537596 PMCID: PMC3476393 DOI: 10.1186/1742-4690-9-34] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 04/27/2012] [Indexed: 12/02/2022] Open
Abstract
Background The Nef protein of HIV facilitates virus replication and disease progression in infected patients. This role as pathogenesis factor depends on several genetically separable Nef functions that are mediated by interactions of highly conserved protein-protein interaction motifs with different host cell proteins. By studying the functionality of a series of nef alleles from clinical isolates, we identified a dysfunctional HIV group O Nef in which a highly conserved valine-glycine-phenylalanine (VGF) region, which links a preceding acidic cluster with the following proline-rich motif into an amphipathic surface was deleted. In this study, we aimed to study the functional importance of this VGF region. Results The dysfunctional HIV group O8 nef allele was restored to the consensus sequence, and mutants of canonical (NL4.3, NA-7, SF2) and non-canonical (B2 and C1422) HIV-1 group M nef alleles were generated in which the amino acids of the VGF region were changed into alanines (VGF→AAA) and tested for their capacity to interfere with surface receptor trafficking, signal transduction and enhancement of viral replication and infectivity. We found the VGF motif, and each individual amino acid of this motif, to be critical for downregulation of MHC-I and CXCR4. Moreover, Nef’s association with the cellular p21-activated kinase 2 (PAK2), the resulting deregulation of cofilin and inhibition of host cell actin remodeling, and targeting of Lck kinase to the trans-golgi-network (TGN) were affected as well. Of particular interest, VGF integrity was essential for Nef-mediated enhancement of HIV virion infectivity and HIV replication in peripheral blood lymphocytes. For targeting of Lck kinase to the TGN and viral infectivity, especially the phenylalanine of the triplet was essential. At the molecular level, the VGF motif was required for the physical interaction of the adjacent proline-rich motif with Hck. Conclusion Based on these findings, we propose that this highly conserved three amino acid VGF motif together with the acidic cluster and the proline-rich motif form a previously unrecognized amphipathic surface on Nef. This surface appears to be essential for the majority of Nef functions and thus represents a prime target for the pharmacological inhibition of Nef.
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Affiliation(s)
- Pieter J Meuwissen
- Department of Clinical Chemistry, Microbiology, and Immunology, Ghent University, Ghent, (B-9000), Belgium
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21
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Harthill M. Review: micronutrient selenium deficiency influences evolution of some viral infectious diseases. Biol Trace Elem Res 2011; 143:1325-36. [PMID: 21318622 PMCID: PMC7090490 DOI: 10.1007/s12011-011-8977-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 01/17/2011] [Indexed: 11/13/2022]
Abstract
Recently emerged viral infectious diseases (VIDs) include HIV/AIDS, influenzas H5N1 and 2009 H1N1, SARS, and Ebola hemorrhagic fevers. Earlier research determined metabolic oxidative stress in hosts deficient in antioxidant selenium (Se) (<1 μMol Se/L of blood) induces both impaired human host immunocompetence and rapidly mutated benign variants of RNA viruses to virulence. These viral mutations are consistent, rather than stochastic, and long-lived. When Se-deficient virus-infected hosts were supplemented with dietary Se, viral mutation rates diminished and immunocompetence improved. Herein is described the role of micronutrient Se deficiency on the evolution of some contemporary RNA viruses and their subsequent VIDs. Distinguishing cellular and biomolecular evidence for several VIDs suggests that environmental conditions conducive to chronic dietary Se deprivation could be monitored for bioindicators of incipient viral virulence and subsequent pathogenesis.
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Affiliation(s)
- Michalann Harthill
- Geochemistry and Health International, Inc., Frederick, MD 21705-3523, USA.
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22
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Evans VA, Lal L, Akkina R, Solomon A, Wright E, Lewin SR, Cameron PU. Thymic plasmacytoid dendritic cells are susceptible to productive HIV-1 infection and efficiently transfer R5 HIV-1 to thymocytes in vitro. Retrovirology 2011; 8:43. [PMID: 21639903 PMCID: PMC3118182 DOI: 10.1186/1742-4690-8-43] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 06/03/2011] [Indexed: 01/28/2023] Open
Abstract
Background HIV-1 infection of the thymus contributes to the defective regeneration and loss of CD4+ T cells in HIV-1-infected individuals. As thymic dendritic cells (DC) are permissive to infection by HIV-1, we examined the ability of thymic DC to enhance infection of thymocytes which may contribute to the overall depletion of CD4+ T cells. We compared productive infection in isolated human thymic and blood CD11c+ myeloid DC (mDC) and CD123+ plasmacytoid DC (pDC) using enhanced green fluorescent protein (EGFP) CCR5 (R5)-tropic NL(AD8) and CXCR4 (X4)-tropic NL4-3 HIV-1 reporter viruses. Transfer of productive HIV-1 infection from thymic mDC and pDC was determined by culturing these DC subsets either alone or with sorted thymocytes. Results Productive infection was observed in both thymic pDC and mDC following exposure to R5 HIV-1 and X4 HIV-1. Thymic pDC were more frequently productively infected by both R5 and X4 HIV-1 than thymic mDC (p = 0.03; n = 6). Thymic pDC efficiently transferred productive R5 HIV-1 infection to both CD3hi (p = 0.01; mean fold increase of 6.5; n = 6) and CD3lo thymocytes (mean fold increase of 1.6; n = 2). In comparison, transfer of productive infection by thymic mDC was not observed for either X4 or R5 HIV-1. Conclusions The capacity of thymic pDC to efficiently transfer R5 HIV-1 to both mature and immature thymocytes that are otherwise refractory to R5 virus may represent a pathway to early infection and impaired production of thymocytes and CD4+ T cells in HIV-1-infected individuals.
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Affiliation(s)
- Vanessa A Evans
- Monash University, Department of Medicine, Central and Eastern Clinical School, Alfred Campus, Commercial Rd., Melbourne, Victoria 3004, Australia
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23
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Breuer S, Schievink SI, Schulte A, Blankenfeldt W, Fackler OT, Geyer M. Molecular design, functional characterization and structural basis of a protein inhibitor against the HIV-1 pathogenicity factor Nef. PLoS One 2011; 6:e20033. [PMID: 21625496 PMCID: PMC3098852 DOI: 10.1371/journal.pone.0020033] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 04/10/2011] [Indexed: 12/31/2022] Open
Abstract
Increased spread of HIV-1 and rapid emergence of drug resistance warrants development of novel antiviral strategies. Nef, a critical viral pathogenicity factor that interacts with host cell factors but lacks enzymatic activity, is not targeted by current antiviral measures. Here we inhibit Nef function by simultaneously blocking several highly conserved protein interaction surfaces. This strategy, referred to as “wrapping Nef”, is based on structure-function analyses that led to the identification of four target sites: (i) SH3 domain interaction, (ii) interference with protein transport processes, (iii) CD4 binding and (iv) targeting to lipid membranes. Screening combinations of Nef-interacting domains, we developed a series of small Nef interacting proteins (NIs) composed of an SH3 domain optimized for binding to Nef, fused to a sequence motif of the CD4 cytoplasmic tail and combined with a prenylation signal for membrane association. NIs bind to Nef in the low nM affinity range, associate with Nef in human cells and specifically interfere with key biological activities of Nef. Structure determination of the Nef-inhibitor complex reveals the molecular basis for binding specificity. These results establish Nef-NI interfaces as promising leads for the development of potent Nef inhibitors.
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Affiliation(s)
- Sebastian Breuer
- Abteilung Physikalische Biochemie, Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany
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Nef does not inhibit F-actin remodelling and HIV-1 cell-cell transmission at the T lymphocyte virological synapse. Eur J Cell Biol 2010; 90:913-21. [PMID: 21044805 DOI: 10.1016/j.ejcb.2010.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 09/07/2010] [Accepted: 09/22/2010] [Indexed: 11/24/2022] Open
Abstract
Nef, a HIV-1 pathogenesis factor, elevates virus replication in vivo and thus progression to AIDS by incompletely defined mechanisms. As one of its biological properties, Nef enhances the infectivity of cell-free HIV-1 particles in single round infections, however it fails to provide a significant and amplifying growth advantage for HIV-1 on such virus producing cells. A major difference between HIV-1 cell-free single round infections and virus replication kinetics on T lymphocytes consists in the predominant role of cell-associated virus transmission rather than cell-free infection during multiple round virus replication. HIV-1 cell-to-cell transmission occurs across close cell contacts also referred to as virological synapse (VS) and involves polarization of the F-actin cytoskeleton, formation of F-actin rich membrane bridges as well as virus budding to cell-cell contacts. Since Nef potently interferes with triggered actin remodelling in several cell systems to reduce e.g. cell motility and signal transduction, we set out here to address whether Nef also affects organization and possibly function of the T lymphocyte VS. We find that in addition to increasing infectivity of cell-free virions, Nef can also moderately enhance single rounds of HIV-1 cell-cell transmission between Jurkat T lymphocytes. This occurs without affecting cell conjugation efficiencies or polarization of F-actin and HIV-1 p24Gag at the VS, identifying actin remodelling at the VS as an example of Nef-insensitive host cell actin rearrangements. However, Nef-mediated enhancement of single round cell-free infection or cell-to-cell transmission does not potentiate over multiple rounds of infection. These results suggest that Nef affects cell-free and cell-associated HIV-1 infection by the same mechanism acting on the intrinsic infectivity of HIV-1 particles. They further indicate that the high efficacy of cell-to-cell transmission can compensate such infectivity defects. Nef therefore selectively interferes with actin remodelling processes involved in antiviral host cell defense while actin driven processes that promote virus propagation remain unaltered.
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Lenassi M, Cagney G, Liao M, Vaupotic T, Bartholomeeusen K, Cheng Y, Krogan NJ, Plemenitas A, Peterlin BM. HIV Nef is secreted in exosomes and triggers apoptosis in bystander CD4+ T cells. Traffic 2010; 11:110-22. [PMID: 19912576 DOI: 10.1111/j.1600-0854.2009.01006.x] [Citation(s) in RCA: 396] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The HIV accessory protein negative factor (Nef) is one of the earliest and most abundantly expressed viral proteins. It is also found in the serum of infected individuals (Caby MP, Lankar D, Vincendeau-Scherrer C, Raposo G, Bonnerot C. Exosomal-like vesicles are present in human blood plasma. Int Immunol 2005;17:879-887). Extracellular Nef protein has deleterious effects on CD4(+) T cells (James CO, Huang MB, Khan M, Garcia-Barrio M, Powell MD, Bond VC. Extracellular Nef protein targets CD4(+) T cells for apoptosis by interacting with CXCR4 surface receptors. J Virol 2004;78:3099-3109), the primary targets of HIV, and can suppress immunoglobulin class switching in bystander B cells (Qiao X, He B, Chiu A, Knowles DM, Chadburn A, Cerutti A. Human immunodeficiency virus 1 Nef suppresses CD40-dependent immunoglobulin class switching in bystander B cells. Nat Immunol 2006;7:302-310). Nevertheless, the mode of exit of Nef from infected cells remains a conundrum. We found that Nef stimulates its own export via the release of exosomes from all cells examined. Depending on its intracellular location, these Nef exosomes form at the plasma membrane, late endosomes or both compartments in Jurkat, SupT1 and primary T cells, respectively. Nef release through exosomes is conserved also during HIV-1 infection of peripheral blood lymphocytes (PBLs). Released Nef exosomes cause activation-induced cell death of resting PBLs in vitro. Thus, HIV-infected cells export Nef in bioactive vesicles, which facilitate the depletion of CD4(+) T cells that is a hallmark of acquired immunodeficiency syndrome (AIDS).
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Affiliation(s)
- Metka Lenassi
- Departments of Medicine, Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
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Ali SA, Huang MB, Campbell PE, Roth WW, Campbell T, Khan M, Newman G, Villinger F, Powell MD, Bond VC. Genetic characterization of HIV type 1 Nef-induced vesicle secretion. AIDS Res Hum Retroviruses 2010; 26:173-92. [PMID: 20156100 DOI: 10.1089/aid.2009.0068] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The HIV-1 Nef protein is known to be secreted, and our group has shown that Nef is secreted from nef-transfected and HIV-1-infected cells in small exosome-like vesicles (d. 40-100 nm). The role of secreted Nef remains to be fully characterized. Thus, it is important to characterize the nature of and the mechanisms regulating Nef secretion. We hypothesized that specific structural domains on the Nef protein interact with components of the endosomal trafficking machinery, sorting Nef into multivesicular bodies (MVB) and packaging it in exosome-like vesicles. To identify those domains, a series of mutants spanning the entire nef sequence were made and cloned into the expression vector pQB1, which expresses the mutants as Nef-GFP fusion proteins. These constructs were used in transient transfection assays to identify sequences necessary for secretion of the Nef-GFP fusion protein. N-terminal domains were identified as critical for Nef-induced vesicle secretion: (1) a basic cluster of four arginine residues (aa 17, 19, 21, 22), (2) the phosphofurin acidic cluster sequence (PACS; Glu62-65), and (3) a previously uncharacterized domain spanning amino acid residues 66-70 (VGFPV), which we named the secretion modification region (SMR). Additional amino acids P25, 29GVG31, and T44 were identified in HIV-1 Nef as regulating its secretion. These residues have not been associated with other reported Nef functions. The myristoylation domain, ubiquitination lysine residues, and the C-terminal portion of Nef (aa 71-206) had no effect on secretion. A minimal HIV-1 Nef sequence, comprising the identified motifs, was sufficient for Nef-induced vesicle secretion.
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Affiliation(s)
- Syed A. Ali
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Ming-Bo Huang
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Patrick E. Campbell
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - William W. Roth
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Tamika Campbell
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Mahfuz Khan
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Gale Newman
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Francois Villinger
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Michael D. Powell
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Vincent C. Bond
- Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310
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Geuenich S, Kaderali L, Allespach I, Sertel S, Keppler OT. Biological signature characteristics of primary isolates from human immunodeficiency virus type 1 group O in ex vivo human tonsil histocultures. J Virol 2009; 83:10494-503. [PMID: 19706709 PMCID: PMC2753123 DOI: 10.1128/jvi.00928-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 07/30/2009] [Indexed: 01/09/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) group M viruses have achieved a global distribution, while HIV-1 group O viruses are endemic only in particular regions of Africa. Here, we evaluated biological characteristics of group O and group M viruses in ex vivo models of HIV-1 infection. The replicative capacity and ability to induce CD4 T-cell depletion of eight group O and seven group M primary isolates were monitored in cultures of human peripheral blood mononuclear cells and tonsil explants. Comparative and longitudinal infection studies revealed HIV-1 group-specific activity patterns: CCR5-using (R5) viruses from group M varied considerably in their replicative capacity but showed similar levels of cytopathicity. In contrast, R5 isolates from group O were relatively uniform in their replicative fitness but displayed a high and unprecedented variability in their potential to deplete CD4 T cells. Two R5 group O isolates were identified that cause massive depletion of CD4 T cells, to an extent comparable to CXCR4-using viruses and not documented for any R5 isolate from group M. Intergroup comparisons found a five- to eightfold lower replicative fitness of isolates from group O than for isolates from group M yet a similar overall intrinsic pathogenicity in tonsil cultures. This study establishes biological ex vivo characteristics of HIV-1 group O primary isolates. The current findings challenge the belief that a grossly reduced replicative fitness or inherently impaired cytopathicity of viruses from this group underlies their low global prevalence.
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Affiliation(s)
- Silvia Geuenich
- Department of Virology, University of Heidelberg, Heidelberg, Germany
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