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Aryal CM, Pan J. Probing the interactions of the HIV-1 matrix protein-derived polybasic region with lipid bilayers: insights from AFM imaging and force spectroscopy. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2024; 53:57-67. [PMID: 38172352 DOI: 10.1007/s00249-023-01697-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/18/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024]
Abstract
The human immunodeficiency virus type 1 (HIV-1) matrix protein contains a highly basic region, MA-HBR, crucial for various stages of viral replication. To elucidate the interactions between the polybasic peptide MA-HBR and lipid bilayers, we employed liquid-based atomic force microscopy (AFM) imaging and force spectroscopy on lipid bilayers of differing compositions. In 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers, AFM imaging revealed the formation of annulus-shaped protrusions upon exposure to the polybasic peptide, accompanied by distinctive mechanical responses characterized by enhanced bilayer puncture forces. Importantly, our AFM-based force spectroscopy measurements unveiled that MA-HBR induces interleaflet decoupling within the cohesive bilayer organization. This is evidenced by a force discontinuity observed within the bilayer's elastic deformation regime. In POPC/cholesterol bilayers, MA-HBR caused similar yet smaller annular protrusions, demonstrating an intriguing interplay with cholesterol-rich membranes. In contrast, in bilayers containing anionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS) lipids, MA-HBR induced unique annular protrusions, granular nanoparticles, and nanotubules, showcasing its distinctive effects in anionic lipid-enriched environments. Notably, our force spectroscopy data revealed that anionic POPS lipids weakened interleaflet adhesion within the bilayer, resulting in interleaflet decoupling, which potentially contributes to the specific bilayer perturbations induced by MA-HBR. Collectively, our findings highlight the remarkable variations in how the polybasic peptide, MA-HBR, interacts with lipid bilayers of differing compositions, shedding light on its role in host membrane restructuring during HIV-1 infection.
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Affiliation(s)
- Chinta M Aryal
- Department of Physics, University of South Florida, Tampa, FL, 33620, USA
- , 2920 Burnet Ave Apt 3, Cincinnati, OH, 45219, USA
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL, 33620, USA.
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2
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Boix-Besora A, Gòdia F, Cervera L. Gag Virus-like Particles Functionalized with SARS-CoV-2 Variants: Generation, Characterization and Recognition by COVID-19 Convalescent Patients' Sera. Vaccines (Basel) 2023; 11:1641. [PMID: 38005972 PMCID: PMC10675557 DOI: 10.3390/vaccines11111641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 10/21/2023] [Indexed: 11/26/2023] Open
Abstract
The robustness, safety, versatility, and high immunogenicity of virus-like particles (VLPs) make them a promising approach for the generation of vaccines against a broad range of pathogens. VLPs are recombinant macromolecular structures that closely mimic the native conformation of viruses without carrying viral genetic material. Particularly, HIV-1 Gag-based VLPs are a suitable platform for the presentation of the SARS-CoV-2 Spike (S) protein on their surface. In this context, this work studies the effect of different rationally engineered mutations of the S protein to improve some of its characteristics. The studied variants harbored mutations such as proline substitutions for S stabilization, D614G from the early dominant pandemic form, the elimination of the S1/S2 furin cleavage site to improve S homogeneity, the suppression of a retention motif to favor its membrane localization, and cysteine substitutions to increase its immunogenicity and avoid potential undesired antibody-dependent enhancement (ADE) effects. The influence of the mutations on VLP expression was studied, as well as their immunogenic potential, by testing the recognition of the generated VLP variants by COVID-19 convalescent patients' sera. The results of this work are conceived to give insights on the selection of S protein candidates for their use as immunogens and to showcase the potential of VLPs as carriers for antigen presentation.
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Affiliation(s)
- Arnau Boix-Besora
- Grup d’Enginyeria de Bioprocessos i Biocatàlisi Aplicada ENG4BIO, Escola d’Enginyeria, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
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3
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Zgheib S, Taha N, Zeiger M, Glushonkov O, Lequeu T, Anton H, Didier P, Boutant E, Mély Y, Réal E. The human cellular protein NoL12 is a specific partner of the HIV-1 nucleocapsid protein NCp7. J Virol 2023; 97:e0004023. [PMID: 37695057 PMCID: PMC10537728 DOI: 10.1128/jvi.00040-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 07/12/2023] [Indexed: 09/12/2023] Open
Abstract
The human immunodeficiency virus-1 (HIV-1) nucleocapsid protein (NCp7) is a nucleic acid chaperone protein with two highly conserved zinc fingers. To exert its key roles in the viral cycle, NCp7 interacts with several host proteins. Among them, the human NoL12 protein (hNoL12) was previously identified in genome wide screens as a potential partner of NCp7. hNoL12 is a highly conserved 25 kDa nucleolar RNA-binding protein implicated in the 5'end processing of ribosomal RNA in the nucleolus and thus in the assembly and maturation of ribosomes. In this work, we confirmed the NCp7/hNoL12 interaction in cells by Förster resonance energy transfer visualized by Fluorescence Lifetime Imaging Microscopy and co-immunoprecipitation. The interaction between NCp7 and hNoL12 was found to strongly depend on their both binding to RNA, as shown by the loss of interaction when the cell lysates were pretreated with RNase. Deletion mutants of hNoL12 were tested for their co-immunoprecipitation with NCp7, leading to the identification of the exonuclease domain of hNoL12 as the binding domain for NCp7. Finally, the interaction with hNoL12 was found to be specific of the mature NCp7 and to require NCp7 basic residues. IMPORTANCE HIV-1 mature nucleocapsid (NCp7) results from the maturation of the Gag precursor in the viral particle and is thus mostly abundant in the first phase of the infection which ends with the genomic viral DNA integration in the cell genome. Most if not all the nucleocapsid partners identified so far are not specific of the mature form. We described here the specific interaction in the nucleolus between NCp7 and the human nucleolar protein 12, a protein implicated in ribosomal RNA maturation and DNA damage response. This interaction takes place in the cell nucleolus, a subcellular compartment where NCp7 accumulates. The absence of binding between hNoL12 and Gag makes hNoL12 one of the few known specific cellular partners of NCp7.
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Affiliation(s)
- Sarwat Zgheib
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Nedal Taha
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Manon Zeiger
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Oleksandr Glushonkov
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Thiebault Lequeu
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Halina Anton
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Pascal Didier
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Emmanuel Boutant
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Yves Mély
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Eléonore Réal
- CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
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4
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Mazurov D, Ramadan L, Kruglova N. Packaging and Uncoating of CRISPR/Cas Ribonucleoproteins for Efficient Gene Editing with Viral and Non-Viral Extracellular Nanoparticles. Viruses 2023; 15:v15030690. [PMID: 36992399 PMCID: PMC10056905 DOI: 10.3390/v15030690] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023] Open
Abstract
Rapid progress in gene editing based on clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) has revolutionized functional genomic studies and genetic disease correction. While numerous gene editing applications have been easily adapted by experimental science, the clinical utility of CRISPR/Cas remains very limited due to difficulty in delivery to primary cells and possible off-target effects. The use of CRISPR in the form of a ribonucleoprotein (RNP) complex substantially reduces the time of DNA exposure to the effector nuclease and minimizes its off-target activity. The traditional electroporation and lipofection methods lack the cell-type specificity of RNP delivery, can be toxic for cells, and are less efficient when compared to nanoparticle transporters. This review focuses on CRISPR/Cas RNP packaging and delivery using retro/lentiviral particles and exosomes. First, we briefly describe the natural stages of viral and exosomal particle formation, release and entry into the target cells. This helps us understand the mechanisms of CRISPR/Cas RNP packaging and uncoating utilized by the current delivery systems, which we discuss afterward. Much attention is given to the exosomes released during viral particle production that can be passively loaded with RNPs as well as the mechanisms necessary for particle fusion, RNP release, and transportation inside the target cells. Collectively, together with specific packaging mechanisms, all these factors can substantially influence the editing efficiency of the system. Finally, we discuss ways to improve CRISPR/Cas RNP delivery using extracellular nanoparticles.
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Affiliation(s)
- Dmitriy Mazurov
- Cell and Gene Technology Group, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology RAS, 119334 Moscow, Russia
- Correspondence: or
| | - Lama Ramadan
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Moscow, Russia
| | - Natalia Kruglova
- Cell and Gene Technology Group, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology RAS, 119334 Moscow, Russia
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Piranej S, Zhang L, Bazrafshan A, Marin M, Melikyan GB, Salaita K. Rolosense: Mechanical detection of SARS-CoV-2 using a DNA-based motor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530294. [PMID: 36909543 PMCID: PMC10002644 DOI: 10.1101/2023.02.27.530294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Assays detecting viral infections play a significant role in limiting the spread of diseases such as SARS-CoV-2. Here we present Rolosense, a virus sensing platform that transduces the motion of synthetic DNA-based motors transporting 5-micron particles on RNA fuel chips. Motors and chips are modified with virus-binding aptamers that lead to stalling of motion. Therefore, motors perform a "mechanical test" of viral target and stall in the presence of whole virions which represents a unique mechanism of transduction distinct from conventional assays. Rolosense can detect SARS-CoV-2 spiked in artificial saliva and exhaled breath condensate with a sensitivity of 103 copies/mL and discriminates among other respiratory viruses. The assay is modular and amenable to multiplexing, as we demonstrated one-pot detection of influenza A and SARS-CoV-2. As a proof-of-concept, we show readout can be achieved using a smartphone camera in as little as 15 mins without any sample preparation steps. Taken together, mechanical detection using Rolosense can be broadly applied to any viral target and has the potential to enable rapid, low-cost, point-of-care screening of circulating viruses.
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Affiliation(s)
- Selma Piranej
- Department of Chemistry, Emory University, Atlanta, GA 30322 (USA)
| | - Luona Zhang
- Department of Chemistry, Emory University, Atlanta, GA 30322 (USA)
| | | | - Mariana Marin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322 (USA)
- Children’s Healthcare of Atlanta, Atlanta, Georgia 30322 (USA)
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322 (USA)
- Children’s Healthcare of Atlanta, Atlanta, Georgia 30322 (USA)
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, GA 30322 (USA)
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322 (USA)
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Monette A, Niu M, Maldonado RK, Chang J, Lambert GS, Flanagan JM, Cochrane A, Parent LJ, Mouland AJ. Influence of HIV-1 genomic RNA on the formation of Gag biomolecular condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529585. [PMID: 36865181 PMCID: PMC9980109 DOI: 10.1101/2023.02.23.529585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Biomolecular condensates (BMCs) play an important role in the replication of a growing number of viruses, but many important mechanistic details remain to be elucidated. Previously, we demonstrated that pan-retroviral nucleocapsid (NC) and the HIV-1 pr55 Gag (Gag) proteins phase separate into condensates, and that HIV-1 protease (PR)-mediated maturation of Gag and Gag-Pol precursor proteins yield self-assembling BMCs having HIV-1 core architecture. Using biochemical and imaging techniques, we aimed to further characterize the phase separation of HIV-1 Gag by determining which of its intrinsically disordered regions (IDRs) influence the formation of BMCs and how the HIV-1 viral genomic RNA (gRNA) could influence BMC abundance and size. We found that mutations in the Gag matrix (MA) domain or the NC zinc finger motifs altered condensate number and size in a salt-dependent manner. Gag BMCs were also bimodally influenced by the gRNA, with a condensate-promoting regime at lower protein concentrations and a gel dissolution at higher protein concentrations. Interestingly, incubation of Gag with CD4 + T cell nuclear lysates led to the formation of larger BMCs as compared to much smaller ones observed in the presence of cytoplasmic lysates. These findings suggests that the composition and properties of Gag-containing BMCs may be altered by differential association of host factors in nuclear and cytosolic compartments during virus assembly. This study significantly advances our understanding of HIV-1 Gag BMC formation and provides a foundation for future therapeutic targeting of virion assembly.
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Wang SF, Hung YH, Tsao CH, Chiang CY, Teoh PG, Chiang ML, Lin WH, Hsu DK, Jan HM, Lin HC, Lin CH, Liu FT, Chen HY. Galectin-3 facilitates cell-to-cell HIV-1 transmission by altering the composition of membrane lipid rafts in CD4 T cells. Glycobiology 2022; 32:760-777. [PMID: 35789267 DOI: 10.1093/glycob/cwac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 05/28/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Galectin-3 (GAL3) is a β-galactoside-binding lectin expressed in CD4 T cells infected with human immunodeficiency virus-1 (HIV-1). GAL3 promotes HIV-1 budding by associating with ALIX and Gag p6. GAL3 has been shown to localize in membrane lipid rafts in dendritic cells and positively regulate cell migration. HIV-1 spreads between T cells by forming supramolecular structures (virological synapses [VSs]), whose integrity depends on lipid rafts. Here, we addressed the potential role of GAL3 in cell-to-cell transmission of HIV-1 in CD4 T cells. GAL3 expressed in donor cells was more important for facilitating HIV-1 cell-to-cell transfer than GAL3 expressed in target cells. GAL3 was found to be co-transferred with Gag from HIV-1-positive donor to HIV-1-negative target T cells. HIV-1 infection induced translocation of GAL3 together with Gag to the cell-cell interfaces and colocalize with GM1, where GAL3 facilitated VS formation. GAL3 regulated the coordinated transfer of Gag and flotillin-1 into plasma membrane fractions. Finally, depletion of GAL3 reduced the cholesterol levels in membrane lipid rafts in CD4 T cells. These findings provide evidence that endogenous GAL3 stimulates lipid raft components and facilitates intercellular HIV-1 transfer among CD4 T cells, offering another pathway by which GAL3 regulates HIV-1 infection. These findings may inform the treatment of HIV-1 infection based on targeting GAL3 to modulate lipid rafts.
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Affiliation(s)
- Sheng-Fan Wang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yu-Hsien Hung
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ching-Han Tsao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Ph.D. Program in Translational Medicine, Kaohsiung Medical University and Academia Sinica, Taiwan
| | - Cho-Ying Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Pak-Guan Teoh
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Meng-Lin Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wei-Han Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Daniel K Hsu
- Department of Dermatology, University of California Davis, California, USA
| | - Hau-Ming Jan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsiu-Chu Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chun-Hung Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Fu-Tong Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Dermatology, University of California Davis, California, USA
| | - Huan-Yuan Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Dermatology, University of California Davis, California, USA
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Heterologous Expression of Full-Length and Truncated Human ZIP4 Zinc Transporter in Saccharomyces cerevisiae. Biomolecules 2022; 12:biom12050726. [PMID: 35625653 PMCID: PMC9138318 DOI: 10.3390/biom12050726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/01/2023] Open
Abstract
The human (h) transporter hZIP4 is the primary Zn2+ importer in the intestine. hZIP4 is also expressed in a variety of organs such as the pancreas and brain. Dysfunction of hZIP4 can result in the Zn2+ deficiency disease acrodermatitis enteropathica (AE). AE can disrupt digestive and immune system homeostasis. A limited number of hZIP4 expression strategies have hindered increasing knowledge about this essential transmembrane protein. Here, we report the heterologous expression of hZIP4 in Saccharomyces cerevisiae. Both a wild-type and a mutant S. cerevisiae strain, in which the endogenous Zn2+ transporters were deleted, were used to test the expression and localization of an hZIP4–GFP fusion protein. A full-length hZIP4–GFP and a truncated membrane-domain-only (mhZIP4–GFP) protein were observed to be present in the plasma membrane in yeast.
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9
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Transduction of HEK293 Cells with BacMam Baculovirus Is an Efficient System for the Production of HIV-1 Virus-like Particles. Viruses 2022; 14:v14030636. [PMID: 35337043 PMCID: PMC8954388 DOI: 10.3390/v14030636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/06/2022] [Accepted: 03/15/2022] [Indexed: 12/13/2022] Open
Abstract
Gag virus-like particles (VLPs) are promising vaccine candidates against infectious diseases. VLPs are generally produced using the insect cell/baculovirus expression vector system (BEVS), or in mammalian cells by plasmid DNA transient gene expression (TGE). However, VLPs produced with the insect cell/BEVS are difficult to purify and might not display the appropriate post-translational modifications, whereas plasmid DNA TGE approaches are expensive and have a limited scale-up capability. In this study, the production of Gag VLPs with the BacMam expression system in a suspension culture of HEK293 cells is addressed. The optimal conditions of multiplicity of infection (MOI), viable cell density (VCD) at infection, and butyric acid (BA) concentration that maximize cell transduction and VLP production are determined. In these conditions, a maximum cell transduction efficiency of 91.5 ± 1.1%, and a VLP titer of 2.8 ± 0.1 × 109 VLPs/mL are achieved. Successful VLP generation in transduced HEK293 cells is validated using super-resolution fluorescence microscopy, with VLPs produced resembling immature HIV-1 virions and with an average size comprised in the 100–200 nm range. Additionally, evidence that BacMam transduction occurs via different pathways including dynamin-mediated endocytosis and macropinocytosis is provided. This work puts the basis for future studies aiming at scaling up the BacMam baculovirus system as an alternative strategy for VLP production.
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10
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Sumner C, Kotani O, Liu S, Musier-Forsyth K, Sato H, Ono A. Molecular Determinants in tRNA D-arm Required for Inhibition of HIV-1 Gag Membrane Binding. J Mol Biol 2022; 434:167390. [PMID: 34883117 PMCID: PMC8752508 DOI: 10.1016/j.jmb.2021.167390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 02/01/2023]
Abstract
Plasma-membrane-specific localization of Gag, an essential step in HIV-1 particle assembly, is regulated by the interaction of the Gag MA domain with PI(4,5)P2 and tRNA-mediated inhibition of non-specific or premature membrane binding. Different tRNAs inhibit PI(4,5)P2-independent membrane binding to varying degrees in vitro; however, the structural determinants for this difference remain unknown. Here we demonstrate that membrane binding of full-length Gag synthesized in vitro using reticulocyte lysates is inhibited when RNAs that contain the anticodon arm of tRNAPro, but not that of tRNALys3, are added exogenously. In contrast, in the context of a liposome binding assay in which the effects of tRNAs on purified MA were tested, full-length tRNALys3 showed greater inhibition of MA membrane binding than full-length tRNAPro. While transplantation of the D loop sequence of tRNALys3 into tRNAPro resulted in a modest increase in the inhibitory effect relative to WT tRNAPro, replacing the entire D arm sequence with that of tRNALys3 was necessary to confer the full inhibitory effects upon tRNAPro. Together, these results demonstrate that the D arm of tRNALys3 is a major determinant of strong inhibition of MA membrane binding and that this inhibitory effect requires not only the D loop, which was recently reported to contact the MA highly basic region, but the loop sequence in the context of the D arm structure.
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Affiliation(s)
- Christopher Sumner
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
| | - Osamu Kotani
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shuohui Liu
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Karin Musier-Forsyth
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Hironori Sato
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Akira Ono
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
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11
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Castro-Gonzalez S, Chen Y, Benjamin J, Shi Y, Serra-Moreno R. Residues T 48 and A 49 in HIV-1 NL4-3 Nef are responsible for the counteraction of autophagy initiation, which prevents the ubiquitin-dependent degradation of Gag through autophagosomes. Retrovirology 2021; 18:33. [PMID: 34711257 PMCID: PMC8555152 DOI: 10.1186/s12977-021-00576-y] [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: 07/13/2021] [Accepted: 10/05/2021] [Indexed: 11/21/2022] Open
Abstract
Background Autophagy plays an important role as a cellular defense mechanism against intracellular pathogens, like viruses. Specifically, autophagy orchestrates the recruitment of specialized cargo, including viral components needed for replication, for lysosomal degradation. In addition to this primary role, the cleavage of viral structures facilitates their association with pattern recognition receptors and MHC-I/II complexes, which assists in the modulation of innate and adaptive immune responses against these pathogens. Importantly, whereas autophagy restricts the replicative capacity of human immunodeficiency virus type 1 (HIV-1), this virus has evolved the gene nef to circumvent this process through the inhibition of early and late stages of the autophagy cascade. Despite recent advances, many details of the mutual antagonism between HIV-1 and autophagy still remain unknown. Here, we uncover the genetic determinants that drive the autophagy-mediated restriction of HIV-1 as well as the counteraction imposed by Nef. Additionally, we also examine the implications of autophagy antagonism in HIV-1 infectivity. Results We found that sustained activation of autophagy potently inhibits HIV-1 replication through the degradation of HIV-1 Gag, and that this effect is more prominent for nef-deficient viruses. Gag re-localizes to autophagosomes where it interacts with the autophagosome markers LC3 and SQSTM1. Importantly, autophagy-mediated recognition and recruitment of Gag requires the myristoylation and ubiquitination of this virus protein, two post-translational modifications that are essential for Gag’s central role in virion assembly and budding. We also identified residues T48 and A49 in HIV-1 NL4-3 Nef as responsible for impairing the early stages of autophagy. Finally, a survey of pandemic HIV-1 transmitted/founder viruses revealed that these isolates are highly resistant to autophagy restriction. Conclusions This study provides evidence that autophagy antagonism is important for virus replication and suggests that the ability of Nef to counteract autophagy may have played an important role in mucosal transmission. Hence, disabling Nef in combination with the pharmacological manipulation of autophagy represents a promising strategy to prevent HIV spread. Supplementary Information The online version contains supplementary material available at 10.1186/s12977-021-00576-y.
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Affiliation(s)
| | - Yuexuan Chen
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jared Benjamin
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuhang Shi
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Ruth Serra-Moreno
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.
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12
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Herrmann D, Zhou LW, Hanson HM, Willkomm NA, Mansky LM, Saad JS. Structural Insights into the Mechanism of Human T-cell Leukemia Virus Type 1 Gag Targeting to the Plasma Membrane for Assembly. J Mol Biol 2021; 433:167161. [PMID: 34298060 PMCID: PMC8453114 DOI: 10.1016/j.jmb.2021.167161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 01/10/2023]
Abstract
Retroviral Gag targeting to the plasma membrane (PM) for assembly is mediated by the N-terminal matrix (MA) domain. For many retroviruses, Gag-PM interaction is dependent on phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). However, it has been shown that for human T-cell leukemia virus type 1 (HTLV-1), Gag binding to membranes is less dependent on PI(4,5)P2 than HIV-1, suggesting that other factors may modulate Gag assembly. To elucidate the mechanism by which HTLV-1 Gag binds to the PM, we employed NMR techniques to determine the structure of unmyristoylated MA (myr(-)MA) and to characterize its interactions with lipids and liposomes. The MA structure consists of four α-helices and unstructured N- and C-termini. We show that myr(-)MA binds to PI(4,5)P2 via the polar head and that binding to inositol phosphates (IPs) is significantly enhanced by increasing the number of phosphate groups on the inositol ring, indicating that the MA-IP binding is governed by charge-charge interactions. The IP binding site was mapped to a well-defined basic patch formed by lysine and arginine residues. Using an NMR-based liposome binding assay, we show that PI(4,5)P2and phosphatidylserine enhance myr(-)MA binding in a synergistic fashion. Confocal microscopy data revealed formation of puncta on the PM of Gag expressing cells. However, G2A-Gag mutant, lacking myristoylation, is diffuse and cytoplasmic. These results suggest that although myr(-)MA binds to membranes, myristoylation appears to be key for formation of HTLV-1 Gag puncta on the PM. Altogether, these findings advance our understanding of a key mechanism in retroviral assembly.
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Affiliation(s)
- Dominik Herrmann
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lynne W Zhou
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Heather M Hanson
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Nora A Willkomm
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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13
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Song DH, Garcia G, Situ K, Chua BA, Hong MLO, Do EA, Ramirez CM, Harui A, Arumugaswami V, Morizono K. Development of a blocker of the universal phosphatidylserine- and phosphatidylethanolamine-dependent viral entry pathways. Virology 2021; 560:17-33. [PMID: 34020328 DOI: 10.1016/j.virol.2021.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 12/28/2022]
Abstract
Envelope phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEtr) have been shown to mediate binding of enveloped viruses. However, commonly used PtdSer binding molecules such as Annexin V cannot block PtdSer-mediated viral infection. Lack of reagents that can conceal envelope PtdSer and PtdEtr and subsequently inhibit infection hinders elucidation of the roles of the envelope phospholipids in viral infection. Here, we developed sTIM1dMLDR801, a reagent capable of blocking PtdSer- and PtdEtr-dependent infection of enveloped viruses. Using sTIM1dMLDR801, we found that envelope PtdSer and/or PtdEtr can support ZIKV infection of not only human but also mosquito cells. In a mouse model for ZIKV infection, sTIM1dMLDR801 reduced ZIKV load in serum and the spleen, indicating envelope PtdSer and/or PtdEtr support in viral infection in vivo. sTIM1dMLDR801 will enable elucidation of the roles of envelope PtdSer and PtdEtr in infection of various virus species, thereby facilitating identification of their receptors and transmission mechanisms.
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Affiliation(s)
- Da-Hoon Song
- Division of Hematology and Oncology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; UCLA AIDS Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Gustavo Garcia
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA
| | - Kathy Situ
- Division of Hematology and Oncology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; UCLA AIDS Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Bernadette A Chua
- Division of Hematology and Oncology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; UCLA AIDS Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Madeline Lauren O Hong
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - Elyza A Do
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - Christina M Ramirez
- Department of Biostatistics, UCLA Fielding School of Public Health, University of California, Los Angeles, CA, 90095, USA
| | - Airi Harui
- Division of Pulmonary and Critical Care, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Vaithilingaraja Arumugaswami
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, 90095, USA
| | - Kouki Morizono
- Division of Hematology and Oncology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; UCLA AIDS Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
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14
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Turman JM, Cheplowitz AM, Tiwari C, Thomas T, Joshi D, Bhat M, Wu Q, Pong E, Chu SY, Szymkowski DE, Sharma A, Seveau S, Robinson JM, Kwiek JJ, Burton D, Rajaram MVS, Kim J, Hangartner L, Ganesan LP. Accelerated Clearance and Degradation of Cell-Free HIV by Neutralizing Antibodies Occurs via FcγRIIb on Liver Sinusoidal Endothelial Cells by Endocytosis. THE JOURNAL OF IMMUNOLOGY 2021; 206:1284-1296. [PMID: 33568400 DOI: 10.4049/jimmunol.2000772] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 01/05/2021] [Indexed: 01/19/2023]
Abstract
Neutralizing Abs suppress HIV infection by accelerating viral clearance from blood circulation in addition to neutralization. The elimination mechanism is largely unknown. We determined that human liver sinusoidal endothelial cells (LSEC) express FcγRIIb as the lone Fcγ receptor, and using humanized FcγRIIb mouse, we found that Ab-opsonized HIV pseudoviruses were cleared considerably faster from circulation than HIV by LSEC FcγRIIb. Compared with humanized FcγRIIb-expressing mice, HIV clearance was significantly slower in FcγRIIb knockout mice. Interestingly, a pentamix of neutralizing Abs cleared HIV faster compared with hyperimmune anti-HIV Ig (HIVIG), although the HIV Ab/Ag ratio was higher in immune complexes made of HIVIG and HIV than pentamix and HIV. The effector mechanism of LSEC FcγRIIb was identified to be endocytosis. Once endocytosed, both Ab-opsonized HIV pseudoviruses and HIV localized to lysosomes. This suggests that clearance of HIV, endocytosis, and lysosomal trafficking within LSEC occur sequentially and that the clearance rate may influence downstream events. Most importantly, we have identified LSEC FcγRIIb-mediated endocytosis to be the Fc effector mechanism to eliminate cell-free HIV by Abs, which could inform development of HIV vaccine and Ab therapy.
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Affiliation(s)
- James M Turman
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Alana M Cheplowitz
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Charu Tiwari
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Thushara Thomas
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Dhruvi Joshi
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Menakshi Bhat
- Center for Retrovirus Research, Department of Microbiology, The Ohio State University, Columbus, OH 43210
| | - Qian Wu
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | | | | | | | - Amit Sharma
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210.,Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
| | - Stephanie Seveau
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | - John M Robinson
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210
| | - Jesse J Kwiek
- Center for Retrovirus Research, Department of Microbiology, The Ohio State University, Columbus, OH 43210
| | - Dennis Burton
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037; and
| | - Murugesan V S Rajaram
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115
| | - Lars Hangartner
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037; and
| | - Latha P Ganesan
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210;
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15
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Puente-Massaguer E, Grau-Garcia P, Strobl F, Grabherr R, Striedner G, Lecina M, Gòdia F. Accelerating HIV-1 VLP production using stable High Five insect cell pools. Biotechnol J 2020; 16:e2000391. [PMID: 33247883 DOI: 10.1002/biot.202000391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/21/2020] [Indexed: 12/25/2022]
Abstract
Stable cell pools are receiving a renewed interest as a potential alternative system to clonal cell lines. The shorter development timelines and the capacity to achieve high product yields make them an interesting approach for recombinant protein production. In this study, stable High Five cell pools are assessed for the production of a simple protein, mCherry, and the more complex HIV-1 Gag-eGFP virus-like particles (VLPs). Random integration coupled to fluorescence-activated cell sorting (FACS) in suspension conditions is applied to accelerate the stable cell pool generation process and enrich it with high producer cells. This methodology is successfully transferred to a bioreactor for VLP production, resulting in a 2-fold increase in VLP yields with respect to shake flask cultures. In these conditions, maximum viable cell concentration improves by 1.5-fold, and by-product formation is significantly reduced. Remarkably, a global increase in the uptake of amino acids in the Gag-eGFP stable cell pool is observed when compared with parental High Five cells, reflecting the additional metabolic burden associated with VLP production. These results suggest that stable High Five cell pools are a robust and powerful approach to produce VLPs and other recombinant proteins, and put the basis for future studies aiming to scale up this system.
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Affiliation(s)
- Eduard Puente-Massaguer
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Paula Grau-Garcia
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Florian Strobl
- Austrian Centre of Industrial Biotechnology (acib GmbH), Vienna, 1010, Austria.,Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190, Austria
| | - Reingard Grabherr
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190, Austria
| | - Gerald Striedner
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190, Austria
| | - Martí Lecina
- IQS School of Engineering, Universitat Ramón Llull, Barcelona, 08017, Spain
| | - Francesc Gòdia
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
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16
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Meusser B, Purfuerst B, Luft FC. HIV-1 Gag release from yeast reveals ESCRT interaction with the Gag N-terminal protein region. J Biol Chem 2020; 295:17950-17972. [PMID: 32994219 PMCID: PMC7939435 DOI: 10.1074/jbc.ra120.014710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/25/2020] [Indexed: 11/30/2022] Open
Abstract
The HIV-1 protein Gag assembles at the plasma membrane and drives virion budding, assisted by the cellular endosomal complex required for transport (ESCRT) proteins. Two ESCRT proteins, TSG101 and ALIX, bind to the Gag C-terminal p6 peptide. TSG101 binding is important for efficient HIV-1 release, but how ESCRTs contribute to the budding process and how their activity is coordinated with Gag assembly is poorly understood. Yeast, allowing genetic manipulation that is not easily available in human cells, has been used to characterize the cellular ESCRT function. Previous work reported Gag budding from yeast spheroplasts, but Gag release was ESCRT-independent. We developed a yeast model for ESCRT-dependent Gag release. We combined yeast genetics and Gag mutational analysis with Gag-ESCRT binding studies and the characterization of Gag-plasma membrane binding and Gag release. With our system, we identified a previously unknown interaction between ESCRT proteins and the Gag N-terminal protein region. Mutations in the Gag-plasma membrane-binding matrix domain that reduced Gag-ESCRT binding increased Gag-plasma membrane binding and Gag release. ESCRT knockout mutants showed that the release enhancement was an ESCRT-dependent effect. Similarly, matrix mutation enhanced Gag release from human HEK293 cells. Release enhancement partly depended on ALIX binding to p6, although binding site mutation did not impair WT Gag release. Accordingly, the relative affinity for matrix compared with p6 in GST-pulldown experiments was higher for ALIX than for TSG101. We suggest that a transient matrix-ESCRT interaction is replaced when Gag binds to the plasma membrane. This step may activate ESCRT proteins and thereby coordinate ESCRT function with virion assembly.
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Affiliation(s)
- Birgit Meusser
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | | | - Friedrich C Luft
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Experimental and Clinical Research Center, Berlin, Germany.
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17
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Expression of transgenes enriched in rare codons is enhanced by the MAPK pathway. Sci Rep 2020; 10:22166. [PMID: 33335127 PMCID: PMC7746698 DOI: 10.1038/s41598-020-78453-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/23/2020] [Indexed: 11/10/2022] Open
Abstract
The ability to translate three nucleotide sequences, or codons, into amino acids to form proteins is conserved across all organisms. All but two amino acids have multiple codons, and the frequency that such synonymous codons occur in genomes ranges from rare to common. Transcripts enriched in rare codons are typically associated with poor translation, but in certain settings can be robustly expressed, suggestive of codon-dependent regulation. Given this, we screened a gain-of-function library for human genes that increase the expression of a GFPrare reporter encoded by rare codons. This screen identified multiple components of the mitogen activated protein kinase (MAPK) pathway enhancing GFPrare expression. This effect was reversed with inhibitors of this pathway and confirmed to be both codon-dependent and occur with ectopic transcripts naturally coded with rare codons. Finally, this effect was associated, at least in part, with enhanced translation. We thus identify a potential regulatory module that takes advantage of the redundancy in the genetic code to modulate protein expression.
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18
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HIV-1 Gag Forms Ribonucleoprotein Complexes with Unspliced Viral RNA at Transcription Sites. Viruses 2020; 12:v12111281. [PMID: 33182496 PMCID: PMC7696413 DOI: 10.3390/v12111281] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/28/2020] [Accepted: 11/03/2020] [Indexed: 01/03/2023] Open
Abstract
The ability of the retroviral Gag protein of Rous sarcoma virus (RSV) to transiently traffic through the nucleus is well-established and has been implicated in genomic RNA (gRNA) packaging Although other retroviral Gag proteins (human immunodeficiency virus type 1, HIV-1; feline immunodeficiency virus, FIV; Mason-Pfizer monkey virus, MPMV; mouse mammary tumor virus, MMTV; murine leukemia virus, MLV; and prototype foamy virus, PFV) have also been observed in the nucleus, little is known about what, if any, role nuclear trafficking plays in those viruses. In the case of HIV-1, the Gag protein interacts in nucleoli with the regulatory protein Rev, which facilitates nuclear export of gRNA. Based on the knowledge that RSV Gag forms viral ribonucleoprotein (RNPs) complexes with unspliced viral RNA (USvRNA) in the nucleus, we hypothesized that the interaction of HIV-1 Gag with Rev could be mediated through vRNA to form HIV-1 RNPs. Using inducible HIV-1 proviral constructs, we visualized HIV-1 Gag and USvRNA in discrete foci in the nuclei of HeLa cells by confocal microscopy. Two-dimensional co-localization and RNA-immunoprecipitation of fractionated cells revealed that interaction of nuclear HIV-1 Gag with USvRNA was specific. Interestingly, treatment of cells with transcription inhibitors reduced the number of HIV-1 Gag and USvRNA nuclear foci, yet resulted in an increase in the degree of Gag co-localization with USvRNA, suggesting that Gag accumulates on newly synthesized viral transcripts. Three-dimensional imaging analysis revealed that HIV-1 Gag localized to the perichromatin space and associated with USvRNA and Rev in a tripartite RNP complex. To examine a more biologically relevant cell, latently infected CD4+ T cells were treated with prostratin to stimulate NF-κB mediated transcription, demonstrating striking localization of full-length Gag at HIV-1 transcriptional burst site, which was labelled with USvRNA-specific riboprobes. In addition, smaller HIV-1 RNPs were observed in the nuclei of these cells. These data suggest that HIV-1 Gag binds to unspliced viral transcripts produced at the proviral integration site, forming vRNPs in the nucleus.
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19
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PEI-Mediated Transient Transfection of High Five Cells at Bioreactor Scale for HIV-1 VLP Production. NANOMATERIALS 2020; 10:nano10081580. [PMID: 32806511 PMCID: PMC7466501 DOI: 10.3390/nano10081580] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/20/2020] [Accepted: 08/07/2020] [Indexed: 12/25/2022]
Abstract
High Five cells are an excellent host for the production of virus-like particles (VLPs) with the baculovirus expression vector system (BEVS). However, the concurrent production of high titers of baculovirus hinder the purification of these nanoparticles due to similarities in their physicochemical properties. In this study, first a transient gene expression (TGE) method based on the transfection reagent polyethylenimine (PEI) is optimized for the production of HIV-1 VLPs at shake flask level. Furthermore, VLP production by TGE in High Five cells is successfully demonstrated at bioreactor scale, resulting in a higher maximum viable cell concentration (5.1 × 106 cell/mL), the same transfection efficiency and a 1.8-fold increase in Gag-eGFP VLP production compared to shake flasks. Metabolism analysis of High Five cells indicates a reduction in the consumption of the main metabolites with respect to non-transfected cell cultures, and an increase in the uptake rate of several amino acids when asparagine is depleted. Quality assessment by nanoparticle tracking analysis and flow virometry of the VLPs produced shows an average size of 100–200 nm, in agreement with immature HIV-1 viruses reported in the literature. Overall, this work demonstrates that the High Five/TGE system is a suitable approach for the production of VLP-based vaccine candidates and other recombinant proteins.
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20
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Type I Phosphatidylinositol-4-Phosphate 5-Kinases α and γ Play a Key Role in Targeting HIV-1 Pr55 Gag to the Plasma Membrane. J Virol 2020; 94:JVI.00189-20. [PMID: 32376619 DOI: 10.1128/jvi.00189-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/28/2020] [Indexed: 12/31/2022] Open
Abstract
HIV-1 assembly occurs principally at the plasma membrane (PM) of infected cells. Gag polyprotein precursors (Pr55Gag) are targeted to the PM, and their binding is mediated by the interaction of myristoylated matrix domain and a PM-specific phosphoinositide, the phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]. The major synthesis pathway of PI(4,5)P2 involves the activity of phosphatidylinositol-4-phosphate 5-kinase family type 1 composed of three isoforms (PIP5K1α, PIP5K1β, and PIP5K1γ). To examine whether the activity of a specific PIP5K1 isoform determines proper Pr55Gag localization at the PM, we compared the cellular behavior of Pr55Gag in the context of PIP5K1 inhibition using siRNAs that individually targeted each of the three isoforms in TZM-bl HeLa cells. We found that downregulation of PIP5K1α and PIP5K1γ strongly impaired the targeting of Pr55Gag to the PM with a rerouting of the polyprotein within intracellular compartments. The efficiency of Pr55Gag release was thus impaired through the silencing of these two isoforms, while PIP5K1β is dispensable for Pr55Gag targeting to the PM. The PM mistargeting due to the silencing of PIP5K1α leads to Pr55Gag hydrolysis through lysosome and proteasome pathways, while the silencing of PIP5K1γ leads to Pr55Gag accumulation in late endosomes. Our findings demonstrated that, within the PIP5K1 family, only the PI(4,5)P2 pools produced by PIP5K1α and PIP5K1γ are involved in the Pr55Gag PM targeting process.IMPORTANCE PM specificity of Pr55Gag membrane binding is mediated through the interaction of PI(4,5)P2 with the matrix (MA) basic residues. It was shown that overexpression of a PI(4,5)P2-depleting enzyme strongly impaired PM localization of Pr55Gag However, cellular factors that control PI(4,5)P2 production required for Pr55Gag-PM targeting have not yet been characterized. In this study, by individually inhibiting PIP5K1 isoforms, we elucidated a correlation between PI(4,5)P2 metabolism pathways mediated by PIP5K1 isoforms and the targeting of Pr55Gag to the PM of TZM-bl HeLa cells. Confocal microscopy analyses of cells depleted from PIP5K1α and PIP5K1γ show a rerouting of Pr55Gag to various intracellular compartments. Notably, Pr55Gag is degraded by the proteasome and/or by the lysosomes in PIP5K1α-depleted cells, while Pr55Gag is targeted to endosomal vesicles in PIP5K1γ-depleted cells. Thus, our results highlight, for the first time, the roles of PIP5K1α and PIP5K1γ as determinants of Pr55Gag targeting to the PM.
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21
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Gallinaro A, Borghi M, Pirillo MF, Cecchetti S, Bona R, Canitano A, Michelini Z, Di Virgilio A, Olvera A, Brander C, Negri D, Cara A. Development and Preclinical Evaluation of an Integrase Defective Lentiviral Vector Vaccine Expressing the HIVACAT T Cell Immunogen in Mice. Mol Ther Methods Clin Dev 2020; 17:418-428. [PMID: 32154327 PMCID: PMC7056611 DOI: 10.1016/j.omtm.2020.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 12/25/2022]
Abstract
Cellular immune responses play a fundamental role in controlling viral replication and AIDS progression in human immunodeficiency virus (HIV)-infected subjects and in simian immunodeficiency virus (SIV)-infected macaques. Integrase defective lentiviral vector (IDLV) represents a promising vaccine candidate, inducing functional and durable immune responses in mice and non-human primates. Here, we designed HIV- and SIV-based IDLVs to express the HIVACAT T cell immunogen (HTI), a mosaic antigen designed to cover vulnerable sites in HIV-1 Gag, Pol, Vif, and Nef. We observed that HTI expression during lentiviral vector production interfered profoundly with IDLV particles release because of sequestration of both HIV- and SIV-Gag proteins in the cytoplasm of the vector-producing cells. However, modifications in IDLV design and vector production procedures greatly improved recovery of both HIV- and SIV-based IDLV-HTI. Immunization experiments in BALB/c mice showed that both IDLVs elicited HTI-specific T cell responses. However, immunization with HIV-based IDLV elicited also a T cell response toward exogenous HIV proteins in IDLV particles, suggesting that SIV-based IDLV may be a preferable platform to assess the induction of transgene-specific immune responses against rationally designed HIV structural antigens. These data support the further evaluation of IDLV as an effective platform of T cell immunogens for the development of an effective HIV vaccine.
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Affiliation(s)
| | - Martina Borghi
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | | | - Serena Cecchetti
- Confocal Microscopy Unit NMR, Confocal Microscopy Area Core Facilities, Istituto Superiore di Sanità, Rome, Italy
| | - Roberta Bona
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Andrea Canitano
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Zuleika Michelini
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Antonio Di Virgilio
- Center for Animal Research and Welfare, Istituto Superiore di Sanità, Rome, Italy
| | - Alex Olvera
- Irsicaixa AIDS Research Institute, 08916 Badalona, Catalonia, Spain
- Universitat de Vic-Universitat Central de Catalunya (UVic-UCC), 08500 Vic, Barcelona, Spain
| | - Christian Brander
- Irsicaixa AIDS Research Institute, 08916 Badalona, Catalonia, Spain
- Universitat de Vic-Universitat Central de Catalunya (UVic-UCC), 08500 Vic, Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
- AELIX Therapeutics, Barcelona, Spain
| | - Donatella Negri
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Andrea Cara
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
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22
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Puente-Massaguer E, Saccardo P, Ferrer-Miralles N, Lecina M, Gòdia F. Coupling Microscopy and Flow Cytometry for a Comprehensive Characterization of Nanoparticle Production in Insect Cells. Cytometry A 2020; 97:921-932. [PMID: 32515126 DOI: 10.1002/cyto.a.24033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 01/01/2023]
Abstract
Advancements in the field of characterization techniques have broadened the opportunities to deepen into nanoparticle production bioprocesses. Gag-based virus-like particles (VLPs) have shown their potential as candidates for recombinant vaccine development. However, comprehensive characterization of the production process is still a requirement to meet the desired critical quality attributes. In this work, the production process of Gag VLPs by baculovirus (BV) infection in the reference High Five and Sf9 insect cell lines is characterized in detail. To this end, the Gag polyprotein was fused in frame to the enhanced green fluorescent protein (eGFP) to favor process evaluation with multiple analytical tools. Tracking of the infection process using confocal microscopy and flow cytometry revealed a pronounced increase in the complexity of High Five over Sf9 cells. Cryogenic transmission electron microscopy (cryo-TEM) characterization determined that changes in cell complexity could be attributed to the presence of occlusion-derived BV in High Five cells, whereas Sf9 cells evidenced a larger proportion of the budded virus phenotype (23-fold). Initial evaluation of the VLP production process using spectrofluorometry showed that higher levels of the Gag-eGFP polyprotein were obtained in High Five cells (3.6-fold). However, comparative analysis based on nanoparticle quantification by flow virometry and nanoparticle tracking analysis (NTA) proved that Sf9 cells were 1.7- and 1.5-fold more productive in terms of assembled VLPs, respectively. Finally, analytical ultracentrifugation coupled to flow virometry evidenced a larger sedimentation coefficient of High Five-derived VLPs, indicating a possible interaction with other cellular compounds. Taken together, these results highlight the combined use of microscopy and flow cytometry techniques to improve vaccine development processes using the insect cell/BV expression vector system. © 2020 International Society for Advancement of Cytometry.
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Affiliation(s)
- Eduard Puente-Massaguer
- Departament d'Enginyeria Química, Biològica i Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Paolo Saccardo
- Plataforma de Producción de Proteínas, CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Neus Ferrer-Miralles
- Plataforma de Producción de Proteínas, CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Martí Lecina
- IQS School of Engineering, Universitat Ramón Llull, Barcelona, Spain
| | - Francesc Gòdia
- Departament d'Enginyeria Química, Biològica i Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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González-Domínguez I, Puente-Massaguer E, Cervera L, Gòdia F. Quantification of the HIV-1 virus-like particle production process by super-resolution imaging: From VLP budding to nanoparticle analysis. Biotechnol Bioeng 2020; 117:1929-1945. [PMID: 32242921 DOI: 10.1002/bit.27345] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 03/17/2020] [Accepted: 03/27/2020] [Indexed: 12/31/2022]
Abstract
Virus-like particles (VLPs) offer great promise in the field of nanomedicine. Enveloped VLPs are a class of these nanoparticles and their production process occurs by a budding process, which is known to be the most critical step at intracellular level. In this study, we developed a novel imaging method based on super-resolution fluorescence microscopy (SRFM) to assess the generation of VLPs in living cells. This methodology was applied to study the production of Gag VLPs in three animal cell platforms of reference: HEK 293-transient gene expression (TGE), High Five-baculovirus expression vector system (BEVS) and Sf9-BEVS. Quantification of the number of VLP assembly sites per cell ranged from 500 to 3,000 in the different systems evaluated. Although the BEVS was superior in terms of Gag polyprotein expression, the HEK 293-TGE platform was more efficient regarding the assembly of Gag as VLPs. This was translated into higher levels of non-assembled Gag monomer in BEVS harvested supernatants. Furthermore, the presence of contaminating nanoparticles was evidenced in all three systems, specifically in High Five cells. The SRFM-based method here developed was also successfully applied to measure the concentration of VLPs in crude supernatants. The lipid membrane of VLPs and the presence of nucleic acids alongside these nanoparticles could also be detected using common staining procedures. Overall, a complete picture of the VLP production process was achieved in these three production platforms. The robustness and sensitivity of this new approach broaden the applicability of SRFM toward the development of new detection, diagnosis and quantification methods based on confocal microscopy in living systems.
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Affiliation(s)
- Irene González-Domínguez
- Departament d'Enginyeria Química Biològica i Ambiental, Universitat Autònoma de Barcelona, Barcelona, Bellaterra, Spain
| | - Eduard Puente-Massaguer
- Departament d'Enginyeria Química Biològica i Ambiental, Universitat Autònoma de Barcelona, Barcelona, Bellaterra, Spain
| | - Laura Cervera
- Departament d'Enginyeria Química Biològica i Ambiental, Universitat Autònoma de Barcelona, Barcelona, Bellaterra, Spain
| | - Francesc Gòdia
- Departament d'Enginyeria Química Biològica i Ambiental, Universitat Autònoma de Barcelona, Barcelona, Bellaterra, Spain
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25
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Carravilla P, Nieva JL, Eggeling C. Fluorescence Microscopy of the HIV-1 Envelope. Viruses 2020; 12:E348. [PMID: 32245254 PMCID: PMC7150788 DOI: 10.3390/v12030348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/18/2022] Open
Abstract
Human immunodeficiency virus (HIV) infection constitutes a major health and social issue worldwide. HIV infects cells by fusing its envelope with the target cell plasma membrane. This process is mediated by the viral Env glycoprotein and depends on the envelope lipid composition. Fluorescent microscopy has been employed to investigate the envelope properties, and the processes of viral assembly and fusion, but the application of this technique to the study of HIV is still limited by a number of factors, such as the small size of HIV virions or the difficulty to label the envelope components. Here, we review fluorescence imaging studies of the envelope lipids and proteins, focusing on labelling strategies and model systems.
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Affiliation(s)
- Pablo Carravilla
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany;
- Leibniz Institute of Photonic Technology, Albert Einstein Strasse 9, 07743 Jena, Germany
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain;
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, E-48940 Leioa, Spain
| | - José L. Nieva
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain;
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, E-48940 Leioa, Spain
| | - Christian Eggeling
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany;
- Leibniz Institute of Photonic Technology, Albert Einstein Strasse 9, 07743 Jena, Germany
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK
- Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena, Germany
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Puente-Massaguer E, Lecina M, Gòdia F. Integrating nanoparticle quantification and statistical design of experiments for efficient HIV-1 virus-like particle production in High Five cells. Appl Microbiol Biotechnol 2020; 104:1569-1582. [PMID: 31907573 PMCID: PMC7224031 DOI: 10.1007/s00253-019-10319-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/04/2019] [Accepted: 12/13/2019] [Indexed: 02/06/2023]
Abstract
The nature of enveloped virus-like particles (VLPs) has triggered high interest in their application to different research fields, including vaccine development. The baculovirus expression vector system (BEVS) has been used as an efficient platform for obtaining large amounts of these complex nanoparticles. To date, most of the studies dealing with VLP production by recombinant baculovirus infection utilize indirect detection or quantification techniques that hinder the appropriate characterization of the process and product. Here, we propose the application of cutting-edge quantification methodologies in combination with advanced statistical designs to exploit the full potential of the High Five/BEVS as a platform to produce HIV-1 Gag VLPs. The synergies between CCI, MOI, and TOH were studied using a response surface methodology approach on four different response functions: baculovirus infection, VLP production, VLP assembly, and VLP productivity. TOH and MOI proved to be the major influencing factors in contrast with previous reported data. Interestingly, a remarkable competition between Gag VLP production and non-assembled Gag was detected. Also, the use of nanoparticle tracking analysis and flow virometry revealed the existence of remarkable quantities of extracellular vesicles. The different responses of the study were combined to determine two global optimum conditions, one aiming to maximize the VLP titer (quantity) and the second aiming to find a compromise between VLP yield and the ratio of assembled VLPs (quality). This study provides a valuable approach to optimize VLP production and demonstrates that the High Five/BEVS can support mass production of Gag VLPs and potentially other complex nanoparticles.
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Affiliation(s)
- Eduard Puente-Massaguer
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.
| | - Martí Lecina
- IQS School of Engineering, Universitat Ramón Llull, Barcelona, Spain
| | - Francesc Gòdia
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
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Puente-Massaguer E, Lecina M, Gòdia F. Application of advanced quantification techniques in nanoparticle-based vaccine development with the Sf9 cell baculovirus expression system. Vaccine 2020; 38:1849-1859. [PMID: 31911032 DOI: 10.1016/j.vaccine.2019.11.087] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 12/24/2022]
Abstract
Nanoparticles generated by recombinant technologies are receiving increased interest in several applications, particularly the use of virus like particles (VLPs) for the generation of safer vaccines. The characterization and quantification of these nanoparticles with complex structures is very relevant for a better comprehension of the production systems and should circumvent the limitations of the most conventional quantification techniques often used. Here, we applied confocal microscopy, flow virometry and nanoparticle tracking analysis (NTA) to assess the production process of Gag virus-like particles (VLPs) in the Sf9 cell/baculovirus expression vector system (BEVS). These novel techniques were implemented in an optimization workflow based on Design of Experiments (DoE) and desirability functions to determine the best production conditions. A higher level of sensitivity was observed for NTA and confocal microscopy but flow virometry proved to be more accurate. Interestingly, extracellular vesicles were detected as an important source of contamination of this system. The synergistic interplay of viable cell concentration at infection (CCI), multiplicity of infection (MOI) and time of harvest (TOH) was assessed on five objective responses: VLP assembly, baculovirus infection, VLP production, cell viability and VLP productivity. Two global optimal conditions were defined, one targeting the maximal yield of VLPs and the other providing a balance between production and assembled VLPs. In both cases, a low MOI proved to be the best condition to achieve the highest VLP production and productivity yields. Cryo-EM analysis of nanoparticles produced in these conditions showed the typical size and morphology of HIV-1 VLPs. This study presents an integrative approach based on the combination of DoE and direct nanoparticle quantification techniques to comprehensively optimize the production of VLPs and other viral-based biotherapeutics.
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Affiliation(s)
- Eduard Puente-Massaguer
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Martí Lecina
- IQS School of Engineering, Universitat Ramón Llull, Barcelona, Spain
| | - Francesc Gòdia
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
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28
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Quantification of phosphoinositides reveals strong enrichment of PIP 2 in HIV-1 compared to producer cell membranes. Sci Rep 2019; 9:17661. [PMID: 31776383 PMCID: PMC6881329 DOI: 10.1038/s41598-019-53939-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/09/2019] [Indexed: 02/06/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) acquires its lipid envelope during budding from the plasma membrane of the host cell. Various studies indicated that HIV-1 membranes differ from producer cell plasma membranes, suggesting budding from specialized membrane microdomains. The phosphoinositide PI(4,5)P2 has been of particular interest since PI(4,5)P2 is needed to recruit the viral structural polyprotein Gag to the plasma membrane and thus facilitates viral morphogenesis. While there is evidence for an enrichment of PIP2 in HIV-1, fully quantitative analysis of all phosphoinositides remains technically challenging and therefore has not been reported, yet. Here, we present a comprehensive analysis of the lipid content of HIV-1 and of plasma membranes from infected and non-infected producer cells, resulting in a total of 478 quantified lipid compounds, including molecular species distribution of 25 different lipid classes. Quantitative analyses of phosphoinositides revealed strong enrichment of PIP2, but also of PIP3, in the viral compared to the producer cell plasma membrane. We calculated an average of ca. 8,000 PIP2 molecules per HIV-1 particle, three times more than Gag. We speculate that the high density of PIP2 at the HIV-1 assembly site is mediated by transient interactions with viral Gag polyproteins, facilitating PIP2 concentration in this microdomain. These results are consistent with our previous observation that PIP2 is not only required for recruiting, but also for stably maintaining Gag at the plasma membrane. We believe that this quantitative analysis of the molecular anatomy of the HIV-1 lipid envelope may serve as standard reference for future investigations.
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29
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Salimi H, Johnson J, Flores MG, Zhang MS, O'Malley Y, Houtman JC, Schlievert PM, Haim H. The lipid membrane of HIV-1 stabilizes the viral envelope glycoproteins and modulates their sensitivity to antibody neutralization. J Biol Chem 2019; 295:348-362. [PMID: 31757809 DOI: 10.1074/jbc.ra119.009481] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/19/2019] [Indexed: 11/06/2022] Open
Abstract
The envelope glycoproteins (Envs) of HIV-1 are embedded in the cholesterol-rich lipid membrane of the virus. Chemical depletion of cholesterol from HIV-1 particles inactivates their infectivity. We observed that diverse HIV-1 strains exhibit a range of sensitivities to such treatment. Differences in sensitivity to cholesterol depletion could not be explained by variation in Env components known to interact with cholesterol, including the cholesterol-recognition motif and cytoplasmic tail of gp41. Using antibody-binding assays, measurements of virus infectivity, and analyses of lipid membrane order, we found that depletion of cholesterol from HIV-1 particles decreases the conformational stability of Env. It enhances exposure of partially cryptic epitopes on the trimer and increases sensitivity to structure-perturbing treatments such as antibodies and cold denaturation. Substitutions in the cholesterol-interacting motif of gp41 induced similar effects as depletion of cholesterol. Surface-acting agents, which are incorporated into the virus lipid membrane, caused similar effects as disruption of the Env-cholesterol interaction. Furthermore, substitutions in gp120 that increased structural stability of Env (i.e. induced a "closed" conformation of the trimer) increased virus resistance to cholesterol depletion and to the surface-acting agents. Collectively, these results indicate a critical contribution of the viral membrane to the stability of the Env trimer and to neutralization resistance against antibodies. Our findings suggest that the potency of poorly neutralizing antibodies, which are commonly elicited in vaccinated individuals, may be markedly enhanced by altering the lipid composition of the viral membrane.
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Affiliation(s)
- Hamid Salimi
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jacklyn Johnson
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Manuel G Flores
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Michael S Zhang
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Yunxia O'Malley
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jon C Houtman
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Patrick M Schlievert
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Hillel Haim
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
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Conformational Engineering of HIV-1 Env Based on Mutational Tolerance in the CD4 and PG16 Bound States. J Virol 2019; 93:JVI.00219-19. [PMID: 30894475 DOI: 10.1128/jvi.00219-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/16/2019] [Indexed: 12/22/2022] Open
Abstract
HIV-1 infection is initiated by viral Env engaging the host receptor CD4, triggering Env to transition from a "closed" to "open" conformation during the early events of virus-cell membrane fusion. To understand how Env sequence accommodates this conformational change, mutational landscapes decoupled from virus replication were determined for Env from BaL (clade B) and DU422 (clade C) isolates interacting with CD4 or antibody PG16 that preferentially recognizes closed trimers. Sequence features uniquely important to each bound state were identified, including glycosylation and binding sites. Notably, the Env apical domain and trimerization interface are under selective pressure for PG16 binding. Based on this key observation, mutations were found that increase presentation of quaternary epitopes associated with properly conformed trimers when Env is expressed at the plasma membrane. Many mutations reduce electrostatic repulsion at the Env apex and increase PG16 recognition of Env sequences from clades A and B. Other mutations increase hydrophobic packing at the gp120 inner-outer domain interface and were broadly applicable for engineering Env from diverse strains spanning tiers 1, 2, and 3 across clades A, B, C, and BC recombinants. Core mutations predicted to introduce steric strain in the open state show markedly reduced CD4 interactions. Finally, we demonstrate how our methodology can be adapted to interrogate interactions between membrane-associated Env and the matrix domain of Gag. These findings and methods may assist vaccine design.IMPORTANCE HIV-1 Env is dynamic and undergoes large conformational changes that drive fusion of virus and host cell membranes. Three Env proteins in a trimer contact each other at their apical tips to form a closed conformation that presents epitopes recognized by broadly neutralizing antibodies. The apical tips separate, among other changes, to form an open conformation that binds tightly to host receptors. Understanding how Env sequence facilitates these structural changes can inform the biophysical mechanism and aid immunogen design. Using deep mutational scans decoupled from virus replication, we report mutational landscapes for Env from two strains interacting with conformation-dependent binding proteins. Residues in the Env trimer interface and apical domains are preferentially conserved in the closed conformation, and conformational diversity is facilitated by electrostatic repulsion and an underpacked core between domains. Specific mutations are described that enhance presentation of the trimeric closed conformation across diverse HIV-1 strains.
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31
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Polpitiya Arachchige S, Henke W, Kalamvoki M, Stephens EB. Analysis of herpes simplex type 1 gB, gD, and gH/gL on production of infectious HIV-1: HSV-1 gD restricts HIV-1 by exclusion of HIV-1 Env from maturing viral particles. Retrovirology 2019; 16:9. [PMID: 30940160 PMCID: PMC6444546 DOI: 10.1186/s12977-019-0470-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We previously showed that the gM of HSV-1 could restrict the release of infectious HIV-1 from cells. In this study, we analyzed if the four HSV-1 glycoproteins (gD, gB, and gH/gL), which are the minimum glycoproteins required for HSV-1 entry, restricted the release of infectious HIV-1. RESULTS Of these four glycoproteins, gD and gH/gL restricted the production of infectious HIV-1 from cells transfected with an infectious molecular clone of HIV-1 (strain NL4-3) while gB had no significant effect. Pulse-chase analyses indicated that gD did not affect the biosynthesis and processing of gp160 into gp120/gp41, the transport of the gp120/gp41 to the cell surface, or the release of HIV-1 particles from the cell surface. Our analyses revealed that gD was incorporated into HIV-1 virus particles while gp120/gp41 was excluded from released virus particles. Truncated mutants of gD revealed that the cytoplasmic domain was dispensable but that a membrane bound gD was required for the restriction of release of infectious HIV-1. Finally, cell lines expressing gD also potently restricted the release of infectious virus. CONCLUSIONS Due to its ability to exclude HIV-1 gp120/gp41 from maturing virus, gD may provide a useful tool in deciphering mechanisms of Env incorporation into maturing virus particles.
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Affiliation(s)
- Sachith Polpitiya Arachchige
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, 2000 Hixon Hall, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Wyatt Henke
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, 2000 Hixon Hall, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Maria Kalamvoki
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, 2000 Hixon Hall, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Edward B Stephens
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, 2000 Hixon Hall, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA.
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González-Domínguez I, Grimaldi N, Cervera L, Ventosa N, Gòdia F. Impact of physicochemical properties of DNA/PEI complexes on transient transfection of mammalian cells. N Biotechnol 2019; 49:88-97. [DOI: 10.1016/j.nbt.2018.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 09/24/2018] [Accepted: 09/29/2018] [Indexed: 12/26/2022]
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33
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Hadpech S, Jinathep W, Saoin S, Thongkum W, Chupradit K, Yasamut U, Moonmuang S, Tayapiwatana C. Impairment of a membrane-targeting protein translated from a downstream gene of a "self-cleaving" T2A peptide conjunction. Protein Expr Purif 2018; 150:17-25. [PMID: 29733907 DOI: 10.1016/j.pep.2018.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/26/2018] [Accepted: 05/03/2018] [Indexed: 12/20/2022]
Abstract
The requirement for reliable bicistronic or multicistronic vectors in gene delivery systems is at the forefront of bio/biomedical technology. A method that provides an efficient co-expression of multiple heterologous proteins would be valuable for many applications, especially in medical science for treating various types of disease. In this study, we designed and constructed a bicistronic expression vector using a self-cleaving 2A peptide derived from a virus of the insect Thosea asigna (T2A). This exhibited the most efficient cleavage of the 2A sequence. Two versions of the T2A-based vector were constructed by switching the DNA sequences encoding the proteins of interest, the N-myristoylated protein and the nuclear-homing protein, upstream and downstream of the 2A linker, respectively. Our results showed that similar levels of mRNA expression were found and 100% of cleavage efficiency of T2A was observed. Nevertheless, we also reported the cleared evidence that the N-myristoylated protein cannot be placed downstream of the 2A sequence. Since the protein product fails to translocate to the plasma membrane due to altered myristoylation process, the gene position of the T2A-based vector is meaningful for the subcellular localization of the N-myristoylated protein. Therefore, the observation was marked as a precaution for using the 2A peptide. To adopt the 2A peptide technology for generating the bicistronic or multicistronic expression, the vector design should be carefully considered for the transgene position, signal sequences, and post-translational modifications of each individual protein.
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Affiliation(s)
- Sudarat Hadpech
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Wannarat Jinathep
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Somphot Saoin
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Weeraya Thongkum
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Koollawat Chupradit
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Umpa Yasamut
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Sutpirat Moonmuang
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Chatchai Tayapiwatana
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Biomolecular Therapy and Diagnostic, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.
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Fuenmayor J, Cervera L, Rigau C, Gòdia F. Enhancement of HIV-1 VLP production using gene inhibition strategies. Appl Microbiol Biotechnol 2018; 102:4477-4487. [DOI: 10.1007/s00253-018-8930-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/06/2018] [Accepted: 03/10/2018] [Indexed: 10/17/2022]
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Cervera L, Kamen AA. Large-Scale Transient Transfection of Suspension Mammalian Cells for VLP Production. Methods Mol Biol 2018; 1674:117-127. [PMID: 28921433 DOI: 10.1007/978-1-4939-7312-5_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Large-scale transient transfection of mammalian cell suspension cultures enables the production of biological products in sufficient quantity and under stringent quality attributes to perform accelerated in vitro evaluations and has the potential to support preclinical or even clinical studies. Here we describe the methodology to produce VLPs in a 3L bioreactor, using suspension HEK 293 cells and PEIPro as a transfection reagent. Cells are grown in the bioreactor to 1 × 106 cells/mL and transfected with a plasmid DNA-PEI complex at a ratio of 1:2. Dissolved oxygen and pH are controlled and are online monitored during the production phase and cell growth and viability can be measured off line taking samples from the bioreactor. If the product is labeled with a fluorescent marker, transfection efficiency can be also assessed using flow cytometry analysis. Typically, the production phase lasts between 48 and 96 h until the product is harvested.
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Affiliation(s)
- Laura Cervera
- Bioengineering Department, McGill University, 817 Sherbrooke Street West, Room 270D, Montreal, QC, Canada, H3A 0C3
| | - Amine A Kamen
- Bioengineering Department, McGill University, 817 Sherbrooke Street West, Room 270D, Montreal, QC, Canada, H3A 0C3.
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Production of HIV virus-like particles by transient transfection of CAP-T cells at bioreactor scale avoiding medium replacement. J Biotechnol 2017; 263:11-20. [DOI: 10.1016/j.jbiotec.2017.09.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 09/25/2017] [Accepted: 09/27/2017] [Indexed: 11/20/2022]
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Fuenmayor J, Cervera L, Gutiérrez-Granados S, Gòdia F. Transient gene expression optimization and expression vector comparison to improve HIV-1 VLP production in HEK293 cell lines. Appl Microbiol Biotechnol 2017; 102:165-174. [PMID: 29103166 DOI: 10.1007/s00253-017-8605-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/20/2017] [Accepted: 10/21/2017] [Indexed: 01/01/2023]
Abstract
Transient gene expression (TGE) has been used at small and medium scale for the production of biologicals in sufficient quantities to perform pre-clinical and characterization studies. Polyethyleneimine (PEI)-mediated transfection offers a low toxicity and non-expensive method for cell transfection. DNA and PEI concentration for transient gene expression has been extensively optimized in order to increase product titers. However, the possibility to extrapolate the optimal concentrations found for a specific bioprocess when expression vectors or cell lines need to be changed has not been investigated.In this work, the combination of three different HEK293 cell lines with three different vectors was studied for the production of HIV-1 virus-like particles (VLPs). The concentration of DNA and PEI was optimized for the nine combinations. The obtained results were very similar in all cases (DNA = 2.34 ± 0.18 μg/mL and PEI = 5.81 ± 0.18 μg/mL), revealing that transfection efficiency is not dependent on the cell line or vector type, but on DNA and PEI quantities. Furthermore, two of the cell lines tested stably expressed a protein able to recognize specific origins of replication: HEK293T/SV40 and HEK293E/oriP. Origins of replication were included in the vector sequences in order to test their capacity to increase production titers. HEK293T/SV40 resulted in a decrease of cell density and productivity of 2.3-fold compared to a control plasmid. On the other hand, HEK293E/OriP platform enabled a threefold improvement in HIV-1 VLP production keeping the same cell densities and viabilities compared to a control plasmid.
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Affiliation(s)
- Javier Fuenmayor
- Grup d'Enginyeria Cel·lular i Bioprocés, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain.
| | - Laura Cervera
- Grup d'Enginyeria Cel·lular i Bioprocés, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
| | - Sonia Gutiérrez-Granados
- Grup d'Enginyeria Cel·lular i Bioprocés, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
| | - Francesc Gòdia
- Grup d'Enginyeria Cel·lular i Bioprocés, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
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38
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Cervera L, González-Domínguez I, Segura MM, Gòdia F. Intracellular characterization of Gag VLP production by transient transfection of HEK 293 cells. Biotechnol Bioeng 2017; 114:2507-2517. [DOI: 10.1002/bit.26367] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 01/21/2023]
Affiliation(s)
- Laura Cervera
- Grup d'Enginyeria Cellular i Bioprocés, Escola d'Enginyeria; Universitat Autònoma de Barcelona; Campus de Bellaterra; Cerdanyola del Vallès 08193 Barcelona Spain
| | - Irene González-Domínguez
- Grup d'Enginyeria Cellular i Bioprocés, Escola d'Enginyeria; Universitat Autònoma de Barcelona; Campus de Bellaterra; Cerdanyola del Vallès 08193 Barcelona Spain
| | - María Mercedes Segura
- Bluebird Bio Inc., Pharmaceutical Sciences; Vector Process Development Manufacturing Group; Cambridge Massachusetts
| | - Francesc Gòdia
- Grup d'Enginyeria Cellular i Bioprocés, Escola d'Enginyeria; Universitat Autònoma de Barcelona; Campus de Bellaterra; Cerdanyola del Vallès 08193 Barcelona Spain
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Udenwobele DI, Su RC, Good SV, Ball TB, Varma Shrivastav S, Shrivastav A. Myristoylation: An Important Protein Modification in the Immune Response. Front Immunol 2017; 8:751. [PMID: 28713376 PMCID: PMC5492501 DOI: 10.3389/fimmu.2017.00751] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 06/13/2017] [Indexed: 01/24/2023] Open
Abstract
Protein N-myristoylation is a cotranslational lipidic modification specific to the alpha-amino group of an N-terminal glycine residue of many eukaryotic and viral proteins. The ubiquitous eukaryotic enzyme, N-myristoyltransferase, catalyzes the myristoylation process. Precisely, attachment of a myristoyl group increases specific protein–protein interactions leading to subcellular localization of myristoylated proteins with its signaling partners. The birth of the field of myristoylation, a little over three decades ago, has led to the understanding of the significance of protein myristoylation in regulating cellular signaling pathways in several biological processes especially in carcinogenesis and more recently immune function. This review discusses myristoylation as a prerequisite step in initiating many immune cell signaling cascades. In particular, we discuss the hitherto unappreciated implication of myristoylation during myelopoiesis, innate immune response, lymphopoiesis for T cells, and the formation of the immunological synapse. Furthermore, we discuss the role of myristoylation in inducing the virological synapse during human immunodeficiency virus infection as well as its clinical implication. This review aims to summarize existing knowledge in the field and to highlight gaps in our understanding of the role of myristoylation in immune function so as to further investigate into the dynamics of myristoylation-dependent immune regulation.
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Affiliation(s)
- Daniel Ikenna Udenwobele
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,Department of Biochemistry, University of Nigeria, Nsukka, Enugu, Nigeria
| | - Ruey-Chyi Su
- JC Wilt Infectious Diseases Research Institute, National HIV and Retrovirology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Sara V Good
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada
| | - Terry Blake Ball
- JC Wilt Infectious Diseases Research Institute, National HIV and Retrovirology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada.,Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada
| | - Shailly Varma Shrivastav
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,VastCon Inc., Winnipeg, MB, Canada
| | - Anuraag Shrivastav
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
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Mücksch F, Laketa V, Müller B, Schultz C, Kräusslich HG. Synchronized HIV assembly by tunable PIP 2 changes reveals PIP 2 requirement for stable Gag anchoring. eLife 2017; 6. [PMID: 28574338 PMCID: PMC5495570 DOI: 10.7554/elife.25287] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/25/2017] [Indexed: 12/15/2022] Open
Abstract
HIV-1 assembles at the plasma membrane (PM) of infected cells. PM association of the main structural protein Gag depends on its myristoylated MA domain and PM PI(4,5)P2. Using a novel chemical biology tool that allows rapidly tunable manipulation of PI(4,5)P2 levels in living cells, we show that depletion of PI(4,5)P2 completely prevents Gag PM targeting and assembly site formation. Unexpectedly, PI(4,5)P2 depletion also caused loss of pre-assembled Gag lattices from the PM. Subsequent restoration of PM PI(4,5)P2 reinduced assembly site formation even in the absence of new protein synthesis, indicating that the dissociated Gag molecules remained assembly competent. These results reveal an important role of PI(4,5)P2 for HIV-1 morphogenesis beyond Gag recruitment to the PM and suggest a dynamic equilibrium of Gag-lipid interactions. Furthermore, they establish an experimental system that permits synchronized induction of HIV-1 assembly leading to induced production of infectious virions by targeted modulation of Gag PM targeting.
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Affiliation(s)
- Frauke Mücksch
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Vibor Laketa
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Center for Infectious Disease Research, Partner site Heidelberg, Braunschweig, Germany
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Carsten Schultz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, United States
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.,German Center for Infectious Disease Research, Partner site Heidelberg, Braunschweig, Germany
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41
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Sakin V, Hanne J, Dunder J, Anders-Össwein M, Laketa V, Nikić I, Kräusslich HG, Lemke EA, Müller B. A Versatile Tool for Live-Cell Imaging and Super-Resolution Nanoscopy Studies of HIV-1 Env Distribution and Mobility. Cell Chem Biol 2017; 24:635-645.e5. [PMID: 28457706 DOI: 10.1016/j.chembiol.2017.04.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/12/2017] [Accepted: 04/06/2017] [Indexed: 12/27/2022]
Abstract
The envelope glycoproteins (Env) of HIV-1 mediate cell entry through fusion of the viral envelope with a target cell membrane. Intramembrane mobility and clustering of Env trimers at the viral budding site are essential for its function. Previous live-cell and super-resolution microscopy studies were limited by lack of a functional fluorescent Env derivative, requiring antibody labeling for detection. Introduction of a bio-orthogonal amino acid by genetic code expansion, combined with click chemistry, offers novel possibilities for site-specific, minimally invasive labeling. Using this approach, we established efficient incorporation of non-canonical amino acids within HIV-1 Env in mammalian cells. The engineered protein retained plasma membrane localization, glycosylation, virion incorporation, and fusogenic activity, and could be rapidly and specifically labeled with synthetic dyes. This strategy allowed us to revisit Env dynamics and nanoscale distribution at the plasma membrane close to its native state, applying fluorescence recovery after photo bleaching and STED nanoscopy, respectively.
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Affiliation(s)
- Volkan Sakin
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Janina Hanne
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Optical Nanoscopy Division, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Jessica Dunder
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Maria Anders-Össwein
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Vibor Laketa
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, Partner Site Heidelberg, 69120 Heidelberg, Germany
| | - Ivana Nikić
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, Partner Site Heidelberg, 69120 Heidelberg, Germany
| | - Edward A Lemke
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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42
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Subcellular Localization of HIV-1 gag-pol mRNAs Regulates Sites of Virion Assembly. J Virol 2017; 91:JVI.02315-16. [PMID: 28053097 DOI: 10.1128/jvi.02315-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/23/2016] [Indexed: 02/07/2023] Open
Abstract
Full-length unspliced human immunodeficiency virus type 1 (HIV-1) RNAs serve dual roles in the cytoplasm as mRNAs encoding the Gag and Gag-Pol capsid proteins as well as genomic RNAs (gRNAs) packaged by Gag into virions undergoing assembly at the plasma membrane (PM). Because Gag is sufficient to drive the assembly of virus-like particles even in the absence of gRNA binding, whether viral RNA trafficking plays an active role in the native assembly pathway is unknown. In this study, we tested the effects of modulating the cytoplasmic abundance or distribution of full-length viral RNAs on Gag trafficking and assembly in the context of single cells. Increasing full-length viral RNA abundance or distribution had little-to-no net effect on Gag assembly competency when provided in trans In contrast, artificially tethering full-length viral RNAs or surrogate gag-pol mRNAs competent for Gag synthesis to non-PM membranes or the actin cytoskeleton severely reduced net virus particle production. These effects were explained, in large part, by RNA-directed changes to Gag's distribution in the cytoplasm, yielding aberrant subcellular sites of virion assembly. Interestingly, RNA-dependent disruption of Gag trafficking required either of two cis-acting RNA regulatory elements: the 5' packaging signal (Psi) bound by Gag during genome encapsidation or, unexpectedly, the Rev response element (RRE), which regulates the nuclear export of gRNAs and other intron-retaining viral RNAs. Taken together, these data support a model for native infection wherein structural features of the gag-pol mRNA actively compartmentalize Gag to preferred sites within the cytoplasm and/or PM.IMPORTANCE The spatial distribution of viral mRNAs within the cytoplasm can be a crucial determinant of efficient translation and successful virion production. Here we provide direct evidence that mRNA subcellular trafficking plays an important role in regulating the assembly of human immunodeficiency virus type 1 (HIV-1) virus particles at the plasma membrane (PM). Artificially tethering viral mRNAs encoding Gag capsid proteins (gag-pol mRNAs) to distinct non-PM subcellular locales, such as cytoplasmic vesicles or the actin cytoskeleton, markedly alters Gag subcellular distribution, relocates sites of assembly, and reduces net virus particle production. These observations support a model for native HIV-1 assembly wherein HIV-1 gag-pol mRNA localization helps to confine interactions between Gag, viral RNAs, and host determinants in order to ensure virion production at the right place and right time. Direct perturbation of HIV-1 mRNA subcellular localization may represent a novel antiviral strategy.
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43
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Mates JM, Yao Z, Cheplowitz AM, Suer O, Phillips GS, Kwiek JJ, Rajaram MVS, Kim J, Robinson JM, Ganesan LP, Anderson CL. Mouse Liver Sinusoidal Endothelium Eliminates HIV-Like Particles from Blood at a Rate of 100 Million per Minute by a Second-Order Kinetic Process. Front Immunol 2017; 8:35. [PMID: 28167948 PMCID: PMC5256111 DOI: 10.3389/fimmu.2017.00035] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/09/2017] [Indexed: 01/13/2023] Open
Abstract
We crafted human immunodeficiency virus (HIV)-like particles of diameter about 140 nm, which expressed two major HIV-1 proteins, namely, env and gag gene products, and used this reagent to simulate the rate of decay of HIV from the blood stream of BALB/c male mice. We found that most (~90%) of the particles were eliminated (cleared) from the blood by the liver sinusoidal endothelial cells (LSECs), the remainder from Kupffer cells; suggesting that LSECs are the major liver scavengers for HIV clearance from blood. Decay was rapid with kinetics suggesting second order with respect to particles, which infers dimerization of a putative receptor on LSEC. The number of HIV-like particles required for saturating the clearance mechanism was approximated. The capacity for elimination of blood-borne HIV-like particles by the sinusoid was 112 million particles per minute. Assuming that the sinusoid endothelial cells were about the size of glass-adherent macrophages, then elimination capacity was more than 540 particles per hour per endothelial cell.
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Affiliation(s)
- Jessica M Mates
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
| | - Zhili Yao
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
| | - Alana M Cheplowitz
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
| | - Ozan Suer
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
| | - Gary S Phillips
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University , Columbus, OH , USA
| | - Jesse J Kwiek
- Department of Microbiology, The Ohio State University , Columbus, OH , USA
| | - Murugesan V S Rajaram
- Department of Microbial Infection and Immunity, The Ohio State University , Columbus, OH , USA
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, Northeastern University , Boston, MA , USA
| | - John M Robinson
- Physiology and Cell Biology, The Ohio State University , Columbus, OH , USA
| | - Latha P Ganesan
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
| | - Clark L Anderson
- Departments of Internal Medicine, The Ohio State University , Columbus, OH , USA
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Caccuri F, Iaria ML, Campilongo F, Varney K, Rossi A, Mitola S, Schiarea S, Bugatti A, Mazzuca P, Giagulli C, Fiorentini S, Lu W, Salmona M, Caruso A. Cellular aspartyl proteases promote the unconventional secretion of biologically active HIV-1 matrix protein p17. Sci Rep 2016; 6:38027. [PMID: 27905556 PMCID: PMC5131311 DOI: 10.1038/srep38027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 11/03/2016] [Indexed: 11/24/2022] Open
Abstract
The human immune deficiency virus type 1 (HIV-1) matrix protein p17 (p17), although devoid of a signal sequence, is released by infected cells and detected in blood and in different organs and tissues even in HIV-1-infected patients undergoing successful combined antiretroviral therapy (cART). Extracellularly, p17 deregulates the function of different cells involved in AIDS pathogenesis. The mechanism of p17 secretion, particularly during HIV-1 latency, still remains to be elucidated. A recent study showed that HIV-1-infected cells can produce Gag without spreading infection in a model of viral latency. Here we show that in Gag-expressing cells, secretion of biologically active p17 takes place at the plasma membrane and occurs following its interaction with phosphatidylinositol-(4,5)-bisphosphate and its subsequent cleavage from the precursor Gag (Pr55Gag) operated by cellular aspartyl proteases. These enzymes operate a more complex Gag polypeptide proteolysis than the HIV-1 protease, thus hypothetically generating slightly truncated or elongated p17s in their C-terminus. A 17 C-terminal residues excised p17 was found to be structurally and functionally identical to the full-length p17 demonstrating that the final C-terminal region of p17 is irrelevant for the protein’s biological activity. These findings offer new opportunities to identify treatment strategies for inhibiting p17 release in the extracellular microenvironment.
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Affiliation(s)
- Francesca Caccuri
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Maria Luisa Iaria
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Federica Campilongo
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Kristen Varney
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alessandro Rossi
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Stefania Mitola
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Silvia Schiarea
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Antonella Bugatti
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Pietro Mazzuca
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Cinzia Giagulli
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Simona Fiorentini
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Wuyuan Lu
- Institute of Human Virology, University of Maryland, Baltimore, Maryland, USA
| | - Mario Salmona
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Arnaldo Caruso
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
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45
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HIV Envelope gp120 Alters T Cell Receptor Mobilization in the Immunological Synapse of Uninfected CD4 T Cells and Augments T Cell Activation. J Virol 2016; 90:10513-10526. [PMID: 27630246 DOI: 10.1128/jvi.01532-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/07/2016] [Indexed: 01/21/2023] Open
Abstract
HIV is transmitted most efficiently from cell to cell, and productive infection occurs mainly in activated CD4 T cells. It is postulated that HIV exploits immunological synapses formed between CD4 T cells and antigen-presenting cells to facilitate the targeting and infection of activated CD4 T cells. This study sought to evaluate how the presence of the HIV envelope (Env) in the CD4 T cell immunological synapse affects synapse formation and intracellular signaling to impact the downstream T cell activation events. CD4 T cells were applied to supported lipid bilayers that were reconstituted with HIV Env gp120, anti-T cell receptor (anti-TCR) monoclonal antibody, and ICAM-1 to represent the surface of HIV Env-bearing antigen-presenting cells. The results showed that the HIV Env did not disrupt immunological synapse formation. Instead, the HIV Env accumulated with TCR at the center of the synapse, altered the kinetics of TCR recruitment to the synapse and affected synapse morphology over time. The HIV Env also prolonged Lck phosphorylation at the synapse and enhanced TCR-induced CD69 upregulation, interleukin-2 secretion, and proliferation to promote virus infection. These results suggest that HIV uses the immunological synapse as a conduit not only for selective virus transmission to activated CD4 T cells but also for boosting the T cell activation state, thereby increasing its likelihood of undergoing productive replication in targeted CD4 T cells. IMPORTANCE There are about two million new HIV infections every year. A better understanding of how HIV is transmitted to susceptible cells is critical to devise effective strategies to prevent HIV infection. Activated CD4 T cells are preferentially infected by HIV, although how this is accomplished is not fully understood. This study examined whether HIV co-opts the normal T cell activation process through the so-called immunological synapse. We found that the HIV envelope is recruited to the center of the immunological synapse together with the T cell receptor and enhances the T cell receptor-induced activation of CD4 T cells. Heightened cellular activation promotes the capacity of CD4 T cells to support productive HIV replication. This study provides evidence of the exploitation of the normal immunological synapse and T cell activation process by HIV to boost the activation state of targeted CD4 T cells and promote the infection of these cells.
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46
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Spearman P. HIV-1 Gag as an Antiviral Target: Development of Assembly and Maturation Inhibitors. Curr Top Med Chem 2016; 16:1154-66. [PMID: 26329615 DOI: 10.2174/1568026615666150902102143] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 06/18/2015] [Accepted: 06/21/2015] [Indexed: 01/10/2023]
Abstract
HIV-1 Gag is the master orchestrator of particle assembly. The central role of Gag at multiple stages of the HIV lifecycle has led to efforts to develop drugs that directly target Gag and prevent the formation and release of infectious particles. Until recently, however, only the catalytic site protease inhibitors have been available to inhibit late stages of HIV replication. This review summarizes the current state of development of antivirals that target Gag or disrupt late events in the retrovirus lifecycle such as maturation of the viral capsid. Maturation inhibitors represent an exciting new series of antiviral compounds, including those that specifically target CA-SP1 cleavage and the allosteric integrase inhibitors that inhibit maturation by a completely different mechanism. Numerous small molecules and peptides targeting CA have been studied in attempts to disrupt steps in assembly. Efforts to target CA have recently gained considerable momentum from the development of small molecules that bind CA and alter capsid stability at the post-entry stage of the lifecycle. Efforts to develop antivirals that inhibit incorporation of genomic RNA or to inhibit late budding events remain in preliminary stages of development. Overall, the development of novel antivirals targeting Gag and the late stages in HIV replication appears much closer to success than ever, with the new maturation inhibitors leading the way.
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Affiliation(s)
- Paul Spearman
- Department of Pediatrics; Pediatric Infectious Diseases, Emory University, 2015 Uppergate Drive, Atlanta, GA 30322.
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47
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Inlora J, Chukkapalli V, Bedi S, Ono A. Molecular Determinants Directing HIV-1 Gag Assembly to Virus-Containing Compartments in Primary Macrophages. J Virol 2016; 90:8509-19. [PMID: 27440886 PMCID: PMC5021390 DOI: 10.1128/jvi.01004-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/11/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED The subcellular sites of HIV-1 assembly, determined by the localization of the structural protein Gag, vary in a cell-type-dependent manner. In T cells and transformed cell lines used as model systems, HIV-1 assembles at the plasma membrane (PM). The binding and localization of HIV-1 Gag to the PM are mediated by the interaction between the matrix (MA) domain, specifically the highly basic region, and a PM-specific acidic phospholipid, phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. In primary macrophages, prominent accumulation of assembling or assembled particles is found in the virus-containing compartments (VCCs), which largely consist of convoluted invaginations of the PM. To elucidate the molecular mechanism of HIV-1 Gag targeting to the VCCs, we examined the impact of overexpression of polyphosphoinositide 5-phosphatase IV (5ptaseIV), which depletes cellular PI(4,5)P2, in primary macrophages. We found that the VCC localization and virus release of HIV-1 are severely impaired upon 5ptaseIV overexpression, suggesting an important role for the MA-PI(4,5)P2 interaction in HIV-1 assembly in primary macrophages. However, our analysis of HIV-1 Gag derivatives with MA changes showed that this interaction contributes to Gag membrane binding but is dispensable for specific targeting of Gag to the VCCs per se We further determined that deletion of the NC domain abolishes VCC-specific localization of HIV-1 Gag. Notably, HIV-1 Gag localized efficiently to the VCCs when the NC domain was replaced with a leucine zipper dimerization motif that promotes Gag multimerization. Altogether, our data revealed that targeting of HIV-1 Gag to the VCCs requires NC-dependent multimerization. IMPORTANCE In T cells and model cell lines, HIV-1 Gag localizes to the PM in a manner dependent on the MA-PI(4,5)P2 interaction. On the other hand, in primary macrophages, HIV-1 Gag localizes to convoluted intracellular membrane structures termed virus-containing compartments (VCCs). Although these compartments have been known for decades, and despite the implication of viruses in VCCs being involved in virus reservoir maintenance and spread, the viral determinant(s) that promotes Gag targeting to VCCs is unknown. In this study, we found that the MA-PI(4,5)P2 interaction facilitates efficient Gag membrane binding in macrophages but is not essential for Gag targeting to VCCs. Rather, our results revealed that NC-dependent multimerization promotes VCC targeting. Our findings highlight the differential roles played by MA and NC in HIV-1 Gag membrane binding and targeting and suggest a multimerization-dependent mechanism for Gag trafficking in primary macrophages similar to that for Gag localization to uropods in polarized T cells.
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Affiliation(s)
- Jingga Inlora
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vineela Chukkapalli
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sukhmani Bedi
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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48
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Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
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49
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HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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50
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Sakin V, Paci G, Lemke EA, Müller B. Labeling of virus components for advanced, quantitative imaging analyses. FEBS Lett 2016; 590:1896-914. [PMID: 26987299 DOI: 10.1002/1873-3468.12131] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/31/2022]
Abstract
In recent years, investigation of virus-cell interactions has moved from ensemble measurements to imaging analyses at the single-particle level. Advanced fluorescence microscopy techniques provide single-molecule sensitivity and subdiffraction spatial resolution, allowing observation of subviral details and individual replication events to obtain detailed quantitative information. To exploit the full potential of these techniques, virologists need to employ novel labeling strategies, taking into account specific constraints imposed by viruses, as well as unique requirements of microscopic methods. Here, we compare strengths and limitations of various labeling methods, exemplify virological questions that were successfully addressed, and discuss challenges and future potential of novel approaches in virus imaging.
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Affiliation(s)
- Volkan Sakin
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Germany
| | - Giulia Paci
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Edward A Lemke
- Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Germany
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