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Waheed AA, Zhu Y, Agostino E, Naing L, Hikichi Y, Soheilian F, Yoo SW, Song Y, Zhang P, Slusher BS, Haughey NJ, Freed EO. Neutral sphingomyelinase 2 is required for HIV-1 maturation. Proc Natl Acad Sci U S A 2023; 120:e2219475120. [PMID: 37406093 PMCID: PMC10334776 DOI: 10.1073/pnas.2219475120] [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: 11/18/2022] [Accepted: 04/11/2023] [Indexed: 07/07/2023] Open
Abstract
HIV-1 assembly occurs at the inner leaflet of the plasma membrane (PM) in highly ordered membrane microdomains. The size and stability of membrane microdomains is regulated by activity of the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) that is localized primarily to the inner leaflet of the PM. In this study, we demonstrate that pharmacological inhibition or depletion of nSMase2 in HIV-1-producer cells results in a block in the processing of the major viral structural polyprotein Gag and the production of morphologically aberrant, immature HIV-1 particles with severely impaired infectivity. We find that disruption of nSMase2 also severely inhibits the maturation and infectivity of other primate lentiviruses HIV-2 and simian immunodeficiency virus, has a modest or no effect on nonprimate lentiviruses equine infectious anemia virus and feline immunodeficiency virus, and has no effect on the gammaretrovirus murine leukemia virus. These studies demonstrate a key role for nSMase2 in HIV-1 particle morphogenesis and maturation.
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Affiliation(s)
- Abdul A. Waheed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD21702
| | - Yanan Zhu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, OxfordOX3 7BN, United Kingdom
| | - Eva Agostino
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD21702
| | - Lwar Naing
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD21702
| | - Yuta Hikichi
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD21702
| | - Ferri Soheilian
- Electron Microscopy Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD21702
| | - Seung-Wan Yoo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21287
| | - Yun Song
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, DidcotOX11 0DE, United Kingdom
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, OxfordOX3 7BN, United Kingdom
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, DidcotOX11 0DE, United Kingdom
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, OxfordOX3 7BN, United Kingdom
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21287
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD21287
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21287
| | - Norman J. Haughey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21287
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21287
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD21702
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Lyonnais S, Sadiq SK, Lorca-Oró C, Dufau L, Nieto-Marquez S, Escribà T, Gabrielli N, Tan X, Ouizougun-Oubari M, Okoronkwo J, Reboud-Ravaux M, Gatell JM, Marquet R, Paillart JC, Meyerhans A, Tisné C, Gorelick RJ, Mirambeau G. The HIV-1 Nucleocapsid Regulates Its Own Condensation by Phase-Separated Activity-Enhancing Sequestration of the Viral Protease during Maturation. Viruses 2021; 13:v13112312. [PMID: 34835118 PMCID: PMC8625067 DOI: 10.3390/v13112312] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 02/07/2023] Open
Abstract
A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phase-separated molecular ‘sponges’, stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ∼2400 Gag and ∼120 GagPol by the viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak–strong–moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.
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Affiliation(s)
- Sébastien Lyonnais
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Centre d’Etudes des Maladies Infectieuses et Pharmacologie Anti-Infectieuse (CEMIPAI), CNRS UAR 3725, Université de Montpellier, 1919 Route de Mende, CEDEX 05, 34293 Montpellier, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - S. Kashif Sadiq
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - Cristina Lorca-Oró
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Laure Dufau
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Sara Nieto-Marquez
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Tuixent Escribà
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Natalia Gabrielli
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Xiao Tan
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Mohamed Ouizougun-Oubari
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Josephine Okoronkwo
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Michèle Reboud-Ravaux
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - José Maria Gatell
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Facultat de Medicina y Ciencias de la Salud, Universitat de Barcelona, Carrer de Casanova 143, 08036 Barcelona, Spain
| | - Roland Marquet
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Jean-Christophe Paillart
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Andreas Meyerhans
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
| | - Carine Tisné
- Expression Génétique Microbienne, CNRS UMR 8261, Institut de Biologie Physico-Chimique (IBPC), Université de Paris, 13 Rue Pierre et Marie Curie, 75005 Paris, France;
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA;
| | - Gilles Mirambeau
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biologie Intégrative des Organismes Marins (BIOM), CNRS UMR 7232, Observatoire Océanologique de Banyuls (OOB), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 1 Avenue Pierre Fabre, 66650 Banyuls-sur-Mer, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
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Boutant E, Bonzi J, Anton H, Nasim MB, Cathagne R, Réal E, Dujardin D, Carl P, Didier P, Paillart JC, Marquet R, Mély Y, de Rocquigny H, Bernacchi S. Zinc Fingers in HIV-1 Gag Precursor Are Not Equivalent for gRNA Recruitment at the Plasma Membrane. Biophys J 2020; 119:419-433. [PMID: 32574557 PMCID: PMC7376094 DOI: 10.1016/j.bpj.2020.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/15/2020] [Accepted: 05/06/2020] [Indexed: 01/16/2023] Open
Abstract
The human immunodeficiency virus type 1 Gag precursor specifically selects the unspliced viral genomic RNA (gRNA) from the bulk of cellular and spliced viral RNAs via its nucleocapsid (NC) domain and drives gRNA encapsidation at the plasma membrane (PM). To further identify the determinants governing the intracellular trafficking of Gag-gRNA complexes and their accumulation at the PM, we compared, in living and fixed cells, the interactions between gRNA and wild-type Gag or Gag mutants carrying deletions in NC zinc fingers (ZFs) or a nonmyristoylated version of Gag. Our data showed that the deletion of both ZFs simultaneously or the complete NC domain completely abolished intracytoplasmic Gag-gRNA interactions. Deletion of either ZF delayed the delivery of gRNA to the PM but did not prevent Gag-gRNA interactions in the cytoplasm, indicating that the two ZFs display redundant roles in this respect. However, ZF2 played a more prominent role than ZF1 in the accumulation of the ribonucleoprotein complexes at the PM. Finally, the myristate group, which is mandatory for anchoring the complexes at the PM, was found to be dispensable for the association of Gag with the gRNA in the cytosol.
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Affiliation(s)
- Emmanuel Boutant
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France.
| | - Jeremy Bonzi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg, France
| | - Halina Anton
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Maaz Bin Nasim
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Raphael Cathagne
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Eléonore Réal
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Denis Dujardin
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Philippe Carl
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Pascal Didier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Jean-Christophe Paillart
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg, France
| | - Roland Marquet
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Hugues de Rocquigny
- Morphogenèse et Antigénicité du VIH et des Virus des Hépatites, Inserm - U1259 MAVIVH, Tours, France.
| | - Serena Bernacchi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg, France.
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Pornillos O, Ganser-Pornillos BK. Maturation of retroviruses. Curr Opin Virol 2019; 36:47-55. [PMID: 31185449 PMCID: PMC6730672 DOI: 10.1016/j.coviro.2019.05.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 01/10/2023]
Abstract
During retrovirus maturation, cleavage of the precursor structural Gag polyprotein by the viral protease induces architectural rearrangement of the virus particle from an immature into a mature, infectious form. The structural rearrangement encapsidates the viral RNA genome in a fullerene capsid, producing a diffusible viral core that can initiate infection upon entry into the cytoplasm of a host cell. Maturation is an important therapeutic window against HIV-1. In this review, we highlight recent breakthroughs in understanding of the structures of retroviral immature and mature capsid lattices that define the boundary conditions of maturation and provide novel insights on capsid transformation. We also discuss emerging insights on encapsidation of the viral genome in the mature capsid, as well as remaining questions for further study.
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Affiliation(s)
- Owen Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.
| | - Barbie K Ganser-Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.
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Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation. mBio 2018; 9:mBio.01567-18. [PMID: 30327442 PMCID: PMC6191540 DOI: 10.1128/mbio.01567-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Late in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122-125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122-125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive for in vitro assembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122-125) loop comprises a structural element critical for the formation of the immature Gag lattice.IMPORTANCE Capsid (CA) plays multiple roles in the HIV-1 replication cycle. CA-CA domain interactions are responsible for multimerization of the Gag polyprotein at virus assembly sites, and in the mature virion, CA monomers assemble into a conical core that encapsidates the viral RNA genome. Multiple CA regions that contribute to the assembly and release of HIV-1 particles have been mapped and investigated. Here, we identified and characterized a Pro-rich loop in CA that is important for the formation of the immature Gag lattice. Changes in this region disrupt viral production and abrogate the formation of infectious, mature virions. Propagation of the mutants in culture led to the selection of second-site compensatory mutations within CA. These results expand our knowledge of the assembly and maturation steps in the viral replication cycle and may be relevant for development of antiviral drugs targeting CA.
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Tsukioka T, Takemura S, Minamiyama Y, Mizuguchi S, Toda M, Okada S. Attenuation of Bleomycin-Induced Pulmonary Fibrosis in Rats with S-Allyl Cysteine. Molecules 2017; 22:molecules22040543. [PMID: 28353632 PMCID: PMC6154609 DOI: 10.3390/molecules22040543] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/20/2017] [Accepted: 03/24/2017] [Indexed: 01/24/2023] Open
Abstract
Pulmonary fibrosis is a complex disease with high mortality and morbidity. As there are currently no effective treatments, development of new strategies is essential for improving therapeutic outcomes. S-allyl cysteine (SAC) is a constituent of aged garlic extract that has demonstrated efficacy as an antioxidant and anti-inflammatory agent. The current study examines the effects of SAC on pulmonary fibrosis induced by a single intratracheal instillation of bleomycin (2.5 mg/kg). SAC was administered to rats as 0.15% SAC-containing diet from seven days prior to instillation up until the conclusion of the experiment (14 days post-instillation). SAC significantly reduced collagen mRNA expression and protein deposition (33.3 ± 2.7 μg/mg and 28.2 ± 2.1 μg/mg tissue in vehicle- and SAC-treated rats, respectively), and decreased fibrotic area, as assessed histologically. In the rats’ lungs, SAC also attenuated the increased expression of transforming growth factor-β1 (TGF-β1), a central regulator of myofibroblast recruitment, activation, and differentiation. While bleomycin instillation increased the number of myofibroblasts within the lung mesenchymal area, this change was significantly reduced by SAC treatment. SAC may exert efficacy as an anti-fibrotic by attenuating myofibroblast differentiation through TGF-β1-mediated fibroproliferative processes. Thus, our results indicate SAC may be useful for the prevention or treatment of pulmonary fibrosis.
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Affiliation(s)
- Takuma Tsukioka
- Department of Thoracic Surgery, Osaka City University Graduate School of Medicine, Osaka 5458585, Japan.
| | - Shigekazu Takemura
- Department of Hepato-Biliary-Pancreatic Surgery, Osaka City University Graduate School of Medicine, Osaka 5458585, Japan.
| | - Yukiko Minamiyama
- Department of Hepato-Biliary-Pancreatic Surgery, Osaka City University Graduate School of Medicine, Osaka 5458585, Japan.
- Food Hygiene and Environmental Health Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto 6068522, Japan.
| | - Shinjiro Mizuguchi
- Department of Thoracic Surgery, Osaka City University Graduate School of Medicine, Osaka 5458585, Japan.
| | - Michihito Toda
- Department of Thoracic Surgery, Osaka City University Graduate School of Medicine, Osaka 5458585, Japan.
| | - Shigeru Okada
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 7008558, Japan.
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RNA and Nucleocapsid Are Dispensable for Mature HIV-1 Capsid Assembly. J Virol 2015; 89:9739-47. [PMID: 26178992 DOI: 10.1128/jvi.00750-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/09/2015] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED Human immunodeficiency virus type 1 (HIV-1) is released from infected cells in an immature, noninfectious form in which the structural polyprotein Gag is arranged in a hexameric lattice, forming an incomplete spherical shell. Maturation to the infectious form is mediated by the viral protease, which cleaves Gag at five sites, releasing the CA (capsid) protein, which forms a conical capsid encasing the condensed RNA genome. The pathway of this structural rearrangement is currently not understood, and it is unclear how cone assembly is initiated. RNA represents an integral structural component of retroviruses, and the viral nucleoprotein core has previously been proposed to nucleate mature capsid assembly. We addressed this hypothesis by replacing the RNA-binding NC (nucleocapsid) domain of HIV-1 Gag and the adjacent spacer peptide 2 (SP2) by a leucine zipper (LZ) protein-protein interaction domain [Gag(LZ)] in the viral context. We found that Gag(LZ)-carrying virus [HIV(LZ)] was efficiently released and viral polyproteins were proteolytically processed, though with reduced efficiency. Cryo-electron tomography revealed that the particles lacked a condensed nucleoprotein and contained an increased proportion of aberrant core morphologies caused either by the absence of RNA or by altered Gag processing. Nevertheless, a significant proportion of HIV(LZ) particles contained mature capsids with the wild-type morphology. These results clearly demonstrate that the nucleoprotein complex is dispensable as a nucleator for mature HIV-1 capsid assembly in the viral context. IMPORTANCE Formation of a closed conical capsid encasing the viral RNA genome is essential for HIV-1 infectivity. It is currently unclear what viral components initiate and regulate the formation of the capsid during virus morphogenesis, but it has been proposed that the ribonucleoprotein complex plays a role. To test this, we prepared virus-like particles lacking the viral nucleocapsid protein and RNA and analyzed their three-dimensional structure by cryo-electron tomography. While most virions displayed an abnormal morphology under these conditions, some particles showed a normal mature morphology with closed conical capsids. These data demonstrate that the presence of RNA and the nucleocapsid protein is not required for the formation of a mature, cone-shaped HIV-1 capsid.
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Potempa M, Nalivaika E, Ragland D, Lee SK, Schiffer CA, Swanstrom R. A Direct Interaction with RNA Dramatically Enhances the Catalytic Activity of the HIV-1 Protease In Vitro. J Mol Biol 2015; 427:2360-78. [PMID: 25986307 DOI: 10.1016/j.jmb.2015.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/08/2015] [Accepted: 05/08/2015] [Indexed: 01/09/2023]
Abstract
Though the steps of human immunodeficiency virus type 1 (HIV-1) virion maturation are well documented, the mechanisms regulating the proteolysis of the Gag and Gag-Pro-Pol polyproteins by the HIV-1 protease (PR) remain obscure. One proposed mechanism argues that the maturation intermediate p15NC must interact with RNA for efficient cleavage by the PR. We investigated this phenomenon and found that processing of multiple substrates by the HIV-1 PR was enhanced in the presence of RNA. The acceleration of proteolysis occurred independently from the substrate's ability to interact with nucleic acid, indicating that a direct interaction between substrate and RNA is not necessary for enhancement. Gel-shift assays demonstrated the HIV-1 PR is capable of interacting with nucleic acids, suggesting that RNA accelerates processing reactions by interacting with the PR rather than the substrate. All HIV-1 PRs examined have this ability; however, the HIV-2 PR does not interact with RNA and does not exhibit enhanced catalytic activity in the presence of RNA. No specific sequence or structure was required in the RNA for a productive interaction with the HIV-1 PR, which appears to be principally, though not exclusively, driven by electrostatic forces. For a peptide substrate, RNA increased the kinetic efficiency of the HIV-1 PR by an order of magnitude, affecting both turnover rate (k(cat)) and substrate affinity (K(m)). These results suggest that an allosteric binding site exists on the HIV-1 PR and that HIV-1 PR activity during maturation could be regulated in part by the juxtaposition of the enzyme with virion-packaged RNA.
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Affiliation(s)
- Marc Potempa
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ellen Nalivaika
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Debra Ragland
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sook-Kyung Lee
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ronald Swanstrom
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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9
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Potempa M, Lee SK, Wolfenden R, Swanstrom R. The triple threat of HIV-1 protease inhibitors. Curr Top Microbiol Immunol 2015; 389:203-41. [PMID: 25778681 DOI: 10.1007/82_2015_438] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Newly released human immunodeficiency virus type 1 (HIV-1) particles obligatorily undergo a maturation process to become infectious. The HIV-1 protease (PR) initiates this step, catalyzing the cleavage of the Gag and Gag-Pro-Pol structural polyproteins. Proper organization of the mature virus core requires that cleavage of these polyprotein substrates proceeds in a highly regulated, specific series of events. The vital role the HIV-1 PR plays in the viral life cycle has made it an extremely attractive target for inhibition and has accordingly fostered the development of a number of highly potent substrate-analog inhibitors. Though the PR inhibitors (PIs) inhibit only the HIV-1 PR, their effects manifest at multiple different stages in the life cycle due to the critical importance of the PR in preparing the virus for these subsequent events. Effectively, PIs masquerade as entry inhibitors, reverse transcription inhibitors, and potentially even inhibitors of post-reverse transcription steps. In this chapter, we review the triple threat of PIs: the intermolecular cooperativity in the form of a cooperative dose-response for inhibition in which the apparent potency increases with increasing inhibition; the pleiotropic effects of HIV-1 PR inhibition on entry, reverse transcription, and post-reverse transcription steps; and their potency as transition state analogs that have the potential for further improvement that could lead to an inability of the virus to evolve resistance in the context of single drug therapy.
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Affiliation(s)
- Marc Potempa
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, 27599, USA
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10
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Esteva MJ, Affranchino JL, González SA. Lentiviral Gag assembly analyzed through the functional characterization of chimeric simian immunodeficiency viruses expressing different domains of the feline immunodeficiency virus capsid protein. PLoS One 2014; 9:e114299. [PMID: 25462889 PMCID: PMC4252113 DOI: 10.1371/journal.pone.0114299] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/07/2014] [Indexed: 12/18/2022] Open
Abstract
To gain insight into the functional relationship between the capsid (CA) domains of the Gag polyproteins of simian and feline immunodeficiency viruses (SIV and FIV, respectively), we constructed chimeric SIVs in which the CA-coding region was partially or totally replaced by the equivalent region of the FIV CA. The phenotypic characterization of the chimeras allowed us to group them into three categories: the chimeric viruses that, while being assembly-competent, exhibit a virion-associated unstable FIV CA; a second group represented only by the chimeric SIV carrying the N-terminal domain (NTD) of the FIV CA which proved to be assembly-defective; and a third group constituted by the chimeric viruses that produce virions exhibiting a mature and stable FIV CA protein, and which incorporate the envelope glycoprotein and contain wild-type levels of viral genome RNA and reverse transcriptase. Further analysis of the latter group of chimeric SIVs demonstrated that they are non-infectious due to a post-entry impairment, such as uncoating of the viral core, reverse transcription or nuclear import of the preintegration complex. Furthermore, we show here that the carboxyl-terminus domain (CTD) of the FIV CA has an intrinsic ability to dimerize in vitro and form high-molecular-weight oligomers, which, together with our finding that the FIV CA-CTD is sufficient to confer assembly competence to the resulting chimeric SIV Gag polyprotein, provides evidence that the CA-CTD exhibits more functional plasticity than the CA-NTD. Taken together, our results provide relevant information on the biological relationship between the CA proteins of primate and nonprimate lentiviruses.
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Affiliation(s)
- María J. Esteva
- Laboratorio de Virología, Universidad de Belgrano (UB) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - José L. Affranchino
- Laboratorio de Virología, Universidad de Belgrano (UB) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Silvia A. González
- Laboratorio de Virología, Universidad de Belgrano (UB) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- * E-mail:
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11
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van Bel N, van der Velden Y, Bonnard D, Le Rouzic E, Das AT, Benarous R, Berkhout B. The allosteric HIV-1 integrase inhibitor BI-D affects virion maturation but does not influence packaging of a functional RNA genome. PLoS One 2014; 9:e103552. [PMID: 25072705 PMCID: PMC4114784 DOI: 10.1371/journal.pone.0103552] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 05/20/2014] [Indexed: 12/30/2022] Open
Abstract
The viral integrase (IN) is an essential protein for HIV-1 replication. IN inserts the viral dsDNA into the host chromosome, thereby aided by the cellular co-factor LEDGF/p75. Recently a new class of integrase inhibitors was described: allosteric IN inhibitors (ALLINIs). Although designed to interfere with the IN-LEDGF/p75 interaction to block HIV DNA integration during the early phase of HIV-1 replication, the major impact was surprisingly found on the process of virus maturation during the late phase, causing a reverse transcription defect upon infection of target cells. Virus particles produced in the presence of an ALLINI are misformed with the ribonucleoprotein located outside the virus core. Virus assembly and maturation are highly orchestrated and regulated processes in which several viral proteins and RNA molecules closely interact. It is therefore of interest to study whether ALLINIs have unpredicted pleiotropic effects on these RNA-related processes. We confirm that the ALLINI BI-D inhibits virus replication and that the produced virus is non-infectious. Furthermore, we show that the wild-type level of HIV-1 genomic RNA is packaged in virions and these genomes are in a dimeric state. The tRNAlys3 primer for reverse transcription was properly placed on this genomic RNA and could be extended ex vivo. In addition, the packaged reverse transcriptase enzyme was fully active when extracted from virions. As the RNA and enzyme components for reverse transcription are properly present in virions produced in the presence of BI-D, the inhibition of reverse transcription is likely to reflect the mislocalization of the components in the aberrant virus particle.
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Affiliation(s)
- Nikki van Bel
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Yme van der Velden
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | | | | | - Atze T. Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | | | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- * E-mail:
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12
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Bell NM, L'Hernault A, Murat P, Richards JE, Lever AML, Balasubramanian S. Targeting RNA-protein interactions within the human immunodeficiency virus type 1 lifecycle. Biochemistry 2013; 52:9269-74. [PMID: 24358934 PMCID: PMC3928988 DOI: 10.1021/bi401270d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
RNA–protein
interactions are vital throughout the HIV-1
life cycle for the successful production of infectious virus particles.
One such essential RNA–protein interaction occurs between the
full-length genomic viral RNA and the major structural protein of
the virus. The initial interaction is between the Gag polyprotein
and the viral RNA packaging signal (psi or Ψ), a highly conserved
RNA structural element within the 5′-UTR of the HIV-1 genome,
which has gained attention as a potential therapeutic target. Here,
we report the application of a target-based assay to identify small
molecules, which modulate the interaction between Gag and Ψ.
We then demonstrate that one such molecule exhibits potent inhibitory
activity in a viral replication assay. The mode of binding of the
lead molecules to the RNA target was characterized by 1H NMR spectroscopy.
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Affiliation(s)
- Neil M Bell
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, U.K
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13
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Abstract
Integrase (IN) is required for lentivirus replication and is a proven drug target for the prevention of AIDS in HIV-1-infected patients. While clinical strand transfer inhibitors disarm the IN active site, allosteric inhibition of enzyme activity through the disruption of IN-IN protein interfaces holds great therapeutic potential. A promising class of allosteric IN inhibitors (ALLINIs), 2-(quinolin-3-yl) acetic acid derivatives, engage the IN catalytic core domain dimerisation interface at the binding site for the host integration co-factor LEDGF/p75. ALLINIs promote IN multimerisation and, independent of LEDGF/p75 protein, block the formation of the active IN-DNA complex, as well as inhibit the IN-LEDGF/p75 interaction in vitro. Yet, rather unexpectedly, the full inhibitory effect of these compounds is exerted during the late phase of HIV-1 replication. ALLINIs impair particle core maturation as well as reverse transcription and integration during the subsequent round of virus infection. Recapitulating the pleiotropic phenotypes observed with numerous IN mutant viruses, ALLINIs provide insight into underlying aspects of IN biology that extend beyond its catalytic activity. Therefore, in addition to the potential to expand our repertoire of HIV-1 antiretrovirals, ALLINIs afford important structural probes to dissect the multifaceted nature of the IN protein throughout the course of HIV-1 replication.
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14
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Allosteric integrase inhibitor potency is determined through the inhibition of HIV-1 particle maturation. Proc Natl Acad Sci U S A 2013; 110:8690-5. [PMID: 23610442 DOI: 10.1073/pnas.1300703110] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Integration is essential for HIV-1 replication, and the viral integrase (IN) protein is an important therapeutic target. Allosteric IN inhibitors (ALLINIs) that engage the IN dimer interface at the binding site for the host protein lens epithelium-derived growth factor (LEDGF)/transcriptional coactivator p75 are an emerging class of small molecule antagonists. Consistent with the inhibition of a multivalent drug target, ALLINIs display steep antiviral dose-response curves ex vivo. ALLINIs multimerize IN protein and concordantly block its assembly with viral DNA in vitro, indicating that the disruption of two integration-associated functions, IN catalysis and the IN-LEDGF/p75 interaction, determines the multimode mechanism of ALLINI action. We now demonstrate that ALLINI potency is unexpectedly accounted for during the late phase of HIV-1 replication. The compounds promote virion IN multimerization and, reminiscent of class II IN mutations, block the formation of the electron-dense viral core and inhibit reverse transcription and integration in subsequently infected target cells. Mature virions are recalcitrant to ALLINI treatment, and compound potency during virus production is independent of the level of LEDGF/p75 expression. We conclude that cooperative multimerization of IN by ALLINIs together with the inability for LEDGF/p75 to effectively engage the virus during its egress from cells underscores the multimodal mechanism of ALLINI action. Our results highlight the versatile nature of allosteric inhibitors to primarily inhibit viral replication at a step that is distinct from the catalytic requirement for the target enzyme. The vulnerability of IN to small molecules during the late phase of HIV-1 replication unveils a pharmacological Achilles' heel for exploitation in clinical ALLINI development.
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15
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Álvarez-Fernández C, Crespo Guardo A, García-Pérez J, García F, Blanco J, Escribà-García L, Gatell JM, Alcamí J, Plana M, Sánchez-Palomino S. Generation and characterization of a defective HIV-1 Virus as an immunogen for a therapeutic vaccine. PLoS One 2012; 7:e48848. [PMID: 23144996 PMCID: PMC3492255 DOI: 10.1371/journal.pone.0048848] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 10/01/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The generation of new immunogens able to elicit strong specific immune responses remains a major challenge in the attempts to obtain a prophylactic or therapeutic vaccine against HIV/AIDS. We designed and constructed a defective recombinant virus based on the HIV-1 genome generating infective but non-replicative virions able to elicit broad and strong cellular immune responses in HIV-1 seropositive individuals. RESULTS Viral particles were generated through transient transfection in producer cells (293-T) of a full length HIV-1 DNA carrying a deletion of 892 base pairs (bp) in the pol gene encompassing the sequence that codes for the reverse transcriptase (NL4-3/ΔRT clone). The viral particles generated were able to enter target cells, but due to the absence of reverse transcriptase no replication was detected. The immunogenic capacity of these particles was assessed by ELISPOT to determine γ-interferon production in a cohort of 69 chronic asymptomatic HIV-1 seropositive individuals. Surprisingly, defective particles produced from NL4-3/ΔRT triggered stronger cellular responses than wild-type HIV-1 viruses inactivated with Aldrithiol-2 (AT-2) and in a larger proportion of individuals (55% versus 23% seropositive individuals tested). Electron microscopy showed that NL4-3/ΔRT virions display immature morphology. Interestingly, wild-type viruses treated with Amprenavir (APV) to induce defective core maturation also induced stronger responses than the same viral particles generated in the absence of protease inhibitors. CONCLUSIONS We propose that immature HIV-1 virions generated from NL4-3/ΔRT viral clones may represent new prototypes of immunogens with a safer profile and stronger capacity to induce cellular immune responses than wild-type inactivated viral particles.
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Affiliation(s)
- Carmen Álvarez-Fernández
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Alberto Crespo Guardo
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Javier García-Pérez
- AIDS Immunopathology Unit. National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Felipe García
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Julia Blanco
- Institut de Recerca de la Sindrome de Inmunodeficencia Adquirida, IrsiCaixa, Badalona, Spain-HIVACAT
| | - Laura Escribà-García
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Jose Maria Gatell
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Jose Alcamí
- AIDS Immunopathology Unit. National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Montserrat Plana
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
| | - Sonsoles Sánchez-Palomino
- Institut dInvestigations Biomèdiques August Pi i Sunyer (IDIBAPS)-AIDS Research Group, Hospital Clinic, Catalonian Center for HIV Vaccines (HIVACAT) and University of Barcelona, Barcelona, Spain
- * E-mail:
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16
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Novel two-round phenotypic assay for protease inhibitor susceptibility testing of recombinant and primary HIV-1 isolates. J Clin Microbiol 2012; 50:3909-16. [PMID: 23015664 DOI: 10.1128/jcm.01636-12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antiretroviral drug susceptibility tests facilitate therapeutic management of HIV-1-infected patients. Although genotyping systems are affordable, inaccuracy in the interpretation of complex mutational patterns may limit their usefulness. Currently available HIV-1 phenotypic assays are based on the generation of recombinant viruses in which the specific viral gene of interest, derived from a patient plasma sample, is cloned into a susceptible genetic viral backbone prior to in vitro drug susceptibility evaluation. Nevertheless, in the case of protease inhibitors, not only are mutations in the HIV-1 protease-coding region involved in resistance, but the role of Gag in drug susceptibility has also recently been reported. In order to avoid the inherent limitations resulting from partial cloning of the viral genome, we designed and evaluated a new experimental strategy to test the in vitro susceptibility of primary viral isolates to protease inhibitors. Our protocol, which is based on a two-round infection protocol using the reporter TZM-bl cell line, showed a good correlation with genotypic resistance prediction and with the Antivirogram phenotypic assay, in both protease-recombinant viruses and primary viral isolates. The protocol is suitable for any HIV-1 subtype and enables rapid in-house measurement of protease inhibitor susceptibility, thus making it possible to evaluate the concomitant effects of both patient-derived gag and protease-coding regions.
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17
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Agrawal N, Leaman DP, Rowcliffe E, Kinkead H, Nohria R, Akagi J, Bauer K, Du SX, Whalen RG, Burton DR, Zwick MB. Functional stability of unliganded envelope glycoprotein spikes among isolates of human immunodeficiency virus type 1 (HIV-1). PLoS One 2011; 6:e21339. [PMID: 21738637 PMCID: PMC3124497 DOI: 10.1371/journal.pone.0021339] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 05/26/2011] [Indexed: 01/20/2023] Open
Abstract
The HIV-1 envelope glycoprotein (Env) spike is challenging to study at the molecular level, due in part to its genetic variability, structural heterogeneity and lability. However, the extent of lability in Env function, particularly for primary isolates across clades, has not been explored. Here, we probe stability of function for variant Envs of a range of isolates from chronic and acute infection, and from clades A, B and C, all on a constant virus backbone. Stability is elucidated in terms of the sensitivity of isolate infectivity to destabilizing conditions. A heat-gradient assay was used to determine T90 values, the temperature at which HIV-1 infectivity is decreased by 90% in 1 h, which ranged between ∼40 to 49°C (n = 34). For select Envs (n = 10), the half-lives of infectivity decay at 37°C were also determined and these correlated significantly with the T90 (p = 0.029), though two ‘outliers’ were identified. Specificity in functional Env stability was also evident. For example, Env variant HIV-1ADA was found to be labile to heat, 37°C decay, and guanidinium hydrochloride but not to urea or extremes of pH, when compared to its thermostable counterpart, HIV-1JR-CSF. Blue native PAGE analyses revealed that Env-dependent viral inactivation preceded complete dissociation of Env trimers. The viral membrane and membrane-proximal external region (MPER) of gp41 were also shown to be important for maintaining trimer stability at physiological temperature. Overall, our results indicate that primary HIV-1 Envs can have diverse sensitivities to functional inactivation in vitro, including at physiological temperature, and suggest that parameters of functional Env stability may be helpful in the study and optimization of native Env mimetics and vaccines.
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Affiliation(s)
- Nitish Agrawal
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Daniel P. Leaman
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Eric Rowcliffe
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Heather Kinkead
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Raman Nohria
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Junya Akagi
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Katherine Bauer
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sean X. Du
- AltraVax, Inc., Sunnyvale, California, United States of America
| | | | - Dennis R. Burton
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, California, United States of America
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Boston, Massachusetts, United States of America
| | - Michael B. Zwick
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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18
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Ohishi M, Nakano T, Sakuragi S, Shioda T, Sano K, Sakuragi JI. The relationship between HIV-1 genome RNA dimerization, virion maturation and infectivity. Nucleic Acids Res 2010; 39:3404-17. [PMID: 21186186 PMCID: PMC3082877 DOI: 10.1093/nar/gkq1314] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The relationship between virion protein maturation and genomic RNA dimerization of human immunodeficiency virus type 1 (HIV-1) remains incompletely understood. We have constructed HIV-1 Gag cleavage site mutants to enable the steady state observation of virion maturation steps, and precisely study Gag processing, RNA dimerization, virion morphology and infectivity. Within the virion maturation process, the RNA dimer stabilization begins during the primary cleavage (p2-NC) of Pr55 Gag. However, the primary cleavage alone is not sufficient, and the ensuing cleavages are required for the completion of dimerization. From our observations, the increase of cleavage products may not put a threshold on the transition from fragile to stable dimeric RNA. Most of the RNA dimerization process did not require viral core formation, and particle morphology dynamics during viral maturation did not completely synchronize with the transition of dimeric RNA status. Although the endogenous virion RT activity was fully acquired at the initial step of maturation, the following process was necessary for viral DNA production in infected cell, suggesting the maturation of viral RNA/protein plays critical role for viral infectivity other than RT process.
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Affiliation(s)
- Masahisa Ohishi
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University Suita, Osaka 565-0871, Japan
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19
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Carlson LA, de Marco A, Oberwinkler H, Habermann A, Briggs JAG, Kräusslich HG, Grünewald K. Cryo electron tomography of native HIV-1 budding sites. PLoS Pathog 2010; 6:e1001173. [PMID: 21124872 PMCID: PMC2991257 DOI: 10.1371/journal.ppat.1001173] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 09/30/2010] [Indexed: 12/14/2022] Open
Abstract
The structure of immature and mature HIV-1 particles has been analyzed in detail by cryo electron microscopy, while no such studies have been reported for cellular HIV-1 budding sites. Here, we established a system for studying HIV-1 virus-like particle assembly and release by cryo electron tomography of intact human cells. The lattice of the structural Gag protein in budding sites was indistinguishable from that of the released immature virion, suggesting that its organization is determined at the assembly site without major subsequent rearrangements. Besides the immature lattice, a previously not described Gag lattice was detected in some budding sites and released particles; this lattice was found at high frequencies in a subset of infected T-cells. It displays the same hexagonal symmetry and spacing in the MA-CA layer as the immature lattice, but lacks density corresponding to NC-RNA-p6. Buds and released particles carrying this lattice consistently lacked the viral ribonucleoprotein complex, suggesting that they correspond to aberrant products due to premature proteolytic activation. We hypothesize that cellular and/or viral factors normally control the onset of proteolytic maturation during assembly and release, and that this control has been lost in a subset of infected T-cells leading to formation of aberrant particles. The production of new HIV-1 particles is initiated at the plasma membrane where the viral polyprotein Gag assembles into a budding site, and proceeds through release of an immature virion which is subsequently transformed to the infectious virion by proteolytic cleavage of Gag. Here, we established experimental systems to study HIV-1 budding sites by cryo electron tomography. This technique allows three-dimensional structure determination of single objects at macromolecular resolution, thus being uniquely suited to study variable structures such as HIV-1 particles and budding sites. Using cryo electron tomography, we obtained three-dimensional images with unprecedented detail of the formation of HIV-1 particles. By analyzing these images we show that the organization of released immature HIV-1 is determined at its intracellular assembly without major subsequent rearrangements. We further identify a lattice structure of the viral protein Gag present in budding sites that seem to lack the viral genome and thus cannot be precursors of infectious viruses. We show that some HIV-1 infected T-cells preferentially carry these budding sites, suggesting that they have lost a crucial control of the proteolytic maturation of the virus.
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Affiliation(s)
- Lars-Anders Carlson
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- Department of Molecular Structural Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Alex de Marco
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Heike Oberwinkler
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Anja Habermann
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - John A. G. Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- * E-mail: (HGK); (KG)
| | - Kay Grünewald
- Department of Molecular Structural Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
- Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (HGK); (KG)
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20
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Müller B, Anders M, Akiyama H, Welsch S, Glass B, Nikovics K, Clavel F, Tervo HM, Keppler OT, Kräusslich HG. HIV-1 Gag processing intermediates trans-dominantly interfere with HIV-1 infectivity. J Biol Chem 2009; 284:29692-703. [PMID: 19666477 DOI: 10.1074/jbc.m109.027144] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Protease inhibitors (PI) act by blocking human immunodeficiency virus (HIV) polyprotein processing, but there is no direct quantitative correlation between the degree of impairment of Gag processing and virion infectivity at low PI concentrations. To analyze the consequences of partial processing, virus particles were produced in the presence of limiting PI concentrations or by co-transfection of wild-type proviral plasmids with constructs carrying mutations in one or more cleavage sites. Low PI concentrations caused subtle changes in polyprotein processing associated with a pronounced reduction of particle infectivity. Dissection of individual stages of viral entry indicated a block in accumulation of reverse transcriptase products, whereas virus entry, enzymatic reverse transcriptase activity, and replication steps following reverse transcription were not affected. Co-expression of low amounts of partially processed forms of Gag together with wild-type HIV generally exerted a trans-dominant effect, which was most prominent for a construct carrying mutations at both cleavage sites flanking the CA domain. Interestingly, co-expression of low amounts of Gag mutated at the CA-SP1 cleavage site also affected processing activity at this site in the wild-type virus. The results indicate that low amounts (<5%) of Gag processing intermediates can display a trans-dominant effect on HIV particle maturation, with the maturation cleavage between CA and SP1 being of particular importance. These effects are likely to be important for the strong activity of PI at concentrations achieved in vivo and also bear relevance for the mechanism of action of the antiviral drug bevirimat.
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Affiliation(s)
- Barbara Müller
- Department of Virology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany.
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A strongly transdominant mutation in the human immunodeficiency virus type 1 gag gene defines an Achilles heel in the virus life cycle. J Virol 2009; 83:8536-43. [PMID: 19515760 DOI: 10.1128/jvi.00317-09] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) protease (PR) makes five obligatory cleavages in the viral Gag polyprotein precursor. The cleavage events release the virion structural proteins from the precursor and allow the virion to undergo maturation to become infectious. The protease cleavage between the matrix protein (MA) domain and the adjacent capsid protein (CA) domain releases CA from the membrane-anchored MA and allows the N terminus of CA to refold into a structure that facilitates the formation of hexamer arrays that represent the structural unit of the capsid shell. In this study, we analyzed the extent to which each of the HIV-1 Gag processing sites must be cleaved by substituting the P1-position amino acid at each processing site with Ile. A mutation that blocks cleavage at the MA/CA processing site (Y132I) displayed a strong transdominant effect when tested in a phenotypic mixing strategy, inhibiting virion infectivity with a 50% inhibitory concentration of only 4% of the mutant relative to the wild type. This mutation is 10- to 20-fold more potent in phenotypic mixing than an inactivating mutation in the viral protease, the target of many successful inhibitors, and more potent than an inactivating mutation at any of the other Gag cleavage sites. The transdominant effect is manifested as the assembly of an aberrant virion core. Virus containing 20% of the Y132I mutant and 80% of the wild type (to assess the transdominant effect on infectivity) was blocked either before reverse transcription (RT) or at an early RT step. The ability of a small amount of the MA/CA fusion protein to poison the oligomeric assembly of infectious virus identifies an essential step in the complex process of virion formation and maturation. The effect of a small-molecule inhibitor that is able to block MA/CA cleavage even partially would be amplified by this transdominant negative effect on the highly orchestrated process of virion assembly.
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Kafaie J, Dolatshahi M, Ajamian L, Song R, Mouland AJ, Rouiller I, Laughrea M. Role of capsid sequence and immature nucleocapsid proteins p9 and p15 in Human Immunodeficiency Virus type 1 genomic RNA dimerization. Virology 2009; 385:233-44. [DOI: 10.1016/j.virol.2008.11.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 10/18/2008] [Accepted: 11/14/2008] [Indexed: 11/28/2022]
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