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Jorkesh A, Rothenberger S, Baldassar L, Grybaite B, Kavaliauskas P, Mickevicius V, Dettin M, Vascon F, Cendron L, Pasquato A. Screening of Small-Molecule Libraries Using SARS-CoV-2-Derived Sequences Identifies Novel Furin Inhibitors. Int J Mol Sci 2024; 25:5079. [PMID: 38791119 PMCID: PMC11121672 DOI: 10.3390/ijms25105079] [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: 03/25/2024] [Revised: 04/23/2024] [Accepted: 04/27/2024] [Indexed: 05/26/2024] Open
Abstract
SARS-CoV-2 is the pathogen responsible for the most recent global pandemic, which has claimed hundreds of thousands of victims worldwide. Despite remarkable efforts to develop an effective vaccine, concerns have been raised about the actual protection against novel variants. Thus, researchers are eager to identify alternative strategies to fight against this pathogen. Like other opportunistic entities, a key step in the SARS-CoV-2 lifecycle is the maturation of the envelope glycoprotein at the RARR685↓ motif by the cellular enzyme Furin. Inhibition of this cleavage greatly affects viral propagation, thus representing an ideal drug target to contain infection. Importantly, no Furin-escape variants have ever been detected, suggesting that the pathogen cannot replace this protease by any means. Here, we designed a novel fluorogenic SARS-CoV-2-derived substrate to screen commercially available and custom-made libraries of small molecules for the identification of new Furin inhibitors. We found that a peptide substrate mimicking the cleavage site of the envelope glycoprotein of the Omicron variant (QTQTKSHRRAR-AMC) is a superior tool for screening Furin activity when compared to the commercially available Pyr-RTKR-AMC substrate. Using this setting, we identified promising novel compounds able to modulate Furin activity in vitro and suitable for interfering with SARS-CoV-2 maturation. In particular, we showed that 3-((5-((5-bromothiophen-2-yl)methylene)-4-oxo-4,5 dihydrothiazol-2-yl)(3-chloro-4-methylphenyl)amino)propanoic acid (P3, IC50 = 35 μM) may represent an attractive chemical scaffold for the development of more effective antiviral drugs via a mechanism of action that possibly implies the targeting of Furin secondary sites (exosites) rather than its canonical catalytic pocket. Overall, a SARS-CoV-2-derived peptide was investigated as a new substrate for in vitro high-throughput screening (HTS) of Furin inhibitors and allowed the identification of compound P3 as a promising hit with an innovative chemical scaffold. Given the key role of Furin in infection and the lack of any Food and Drug Administration (FDA)-approved Furin inhibitor, P3 represents an interesting antiviral candidate.
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Affiliation(s)
- Alireza Jorkesh
- Department of Pharmaceutical and Pharmacological Science, University of Padova, Via Marzolo, 5, 35131 Padova, Italy;
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy; (F.V.); (L.C.)
| | - Sylvia Rothenberger
- Institute of Microbiology, University Hospital Center and University of Lausanne, Rue du Bugnon 48, 1011 Lausanne, Switzerland;
- Spiez Laboratory, Federal Office for Civil Protection, Austrasse, 3700 Spiez, Switzerland
| | - Laura Baldassar
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy; (L.B.); (M.D.)
| | - Birute Grybaite
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu Rd. 19, LT-50254 Kaunas, Lithuania; (B.G.); (V.M.)
| | - Povilas Kavaliauskas
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu Rd. 19, LT-50254 Kaunas, Lithuania; (B.G.); (V.M.)
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell University, 1300 York Avenue, New York, NY 10065, USA
- Biological Research Center, Lithuanian University of Health Sciences, Tilzes Str. 18, LT-47181 Kaunas, Lithuania
- Institute of Infectious Diseases and Pathogenic Microbiology, Birstono Str. 38A, LT-59116 Prienai, Lithuania
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Vytautas Mickevicius
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu Rd. 19, LT-50254 Kaunas, Lithuania; (B.G.); (V.M.)
| | - Monica Dettin
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy; (L.B.); (M.D.)
| | - Filippo Vascon
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy; (F.V.); (L.C.)
| | - Laura Cendron
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy; (F.V.); (L.C.)
| | - Antonella Pasquato
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy; (L.B.); (M.D.)
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Lotke R, Petersen M, Sauter D. Restriction of Viral Glycoprotein Maturation by Cellular Protease Inhibitors. Viruses 2024; 16:332. [PMID: 38543698 PMCID: PMC10975521 DOI: 10.3390/v16030332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 05/23/2024] Open
Abstract
The human genome is estimated to encode more than 500 proteases performing a wide range of important physiological functions. They digest proteins in our food, determine the activity of hormones, induce cell death and regulate blood clotting, for example. During viral infection, however, some proteases can switch sides and activate viral glycoproteins, allowing the entry of virions into new target cells and the spread of infection. To reduce unwanted effects, multiple protease inhibitors regulate the proteolytic processing of self and non-self proteins. This review summarizes our current knowledge of endogenous protease inhibitors, which are known to limit viral replication by interfering with the proteolytic activation of viral glycoproteins. We describe the underlying molecular mechanisms and highlight the diverse strategies by which protease inhibitors reduce virion infectivity. We also provide examples of how viruses evade the restriction imposed by protease inhibitors. Finally, we briefly outline how cellular protease inhibitors can be modified and exploited for therapeutic purposes. In summary, this review aims to summarize our current understanding of cellular protease inhibitors as components of our immune response to a variety of viral pathogens.
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Affiliation(s)
| | | | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany
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3
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Pierce CA, Loh LN, Steach HR, Cheshenko N, Preston-Hurlburt P, Zhang F, Stransky S, Kravets L, Sidoli S, Philbrick W, Nassar M, Krishnaswamy S, Herold KC, Herold BC. HSV-2 triggers upregulation of MALAT1 in CD4+ T cells and promotes HIV latency reversal. J Clin Invest 2023; 133:e164317. [PMID: 37079384 PMCID: PMC10232005 DOI: 10.1172/jci164317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 04/17/2023] [Indexed: 04/21/2023] Open
Abstract
Herpes simplex virus type 2 (HSV-2) coinfection is associated with increased HIV-1 viral loads and expanded tissue reservoirs, but the mechanisms are not well defined. HSV-2 recurrences result in an influx of activated CD4+ T cells to sites of viral replication and an increase in activated CD4+ T cells in peripheral blood. We hypothesized that HSV-2 induces changes in these cells that facilitate HIV-1 reactivation and replication and tested this hypothesis in human CD4+ T cells and 2D10 cells, a model of HIV-1 latency. HSV-2 promoted latency reversal in HSV-2-infected and bystander 2D10 cells. Bulk and single-cell RNA-Seq studies of activated primary human CD4+ T cells identified decreased expression of HIV-1 restriction factors and increased expression of transcripts including MALAT1 that could drive HIV replication in both the HSV-2-infected and bystander cells. Transfection of 2D10 cells with VP16, an HSV-2 protein that regulates transcription, significantly upregulated MALAT1 expression, decreased trimethylation of lysine 27 on histone H3 protein, and triggered HIV latency reversal. Knockout of MALAT1 from 2D10 cells abrogated the response to VP16 and reduced the response to HSV-2 infection. These results demonstrate that HSV-2 contributes to HIV-1 reactivation through diverse mechanisms, including upregulation of MALAT1 to release epigenetic silencing.
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Affiliation(s)
- Carl A. Pierce
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, New York, USA
| | - Lip Nam Loh
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, New York, USA
| | | | - Natalia Cheshenko
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, New York, USA
| | | | - Fengrui Zhang
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | | | - Leah Kravets
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, New York, USA
| | | | - William Philbrick
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Michel Nassar
- Department of Otorhinolaryngology–Head and Neck Surgery, Albert Einstein College of Medicine, New York, New York, USA
| | - Smita Krishnaswamy
- Department of Computational Biology
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Kevan C. Herold
- Department of Immunobiology, and
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Betsy C. Herold
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, New York, USA
- Department of Pediatrics, Albert Einstein College of Medicine, New York, New York, USA
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4
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Cassari L, Pavan A, Zoia G, Chinellato M, Zeni E, Grinzato A, Rothenberger S, Cendron L, Dettin M, Pasquato A. SARS-CoV-2 S Mutations: A Lesson from the Viral World to Understand How Human Furin Works. Int J Mol Sci 2023; 24:4791. [PMID: 36902222 PMCID: PMC10003014 DOI: 10.3390/ijms24054791] [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: 01/30/2023] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the etiological agent responsible for the worldwide pandemic and has now claimed millions of lives. The virus combines several unusual characteristics and an extraordinary ability to spread among humans. In particular, the dependence of the maturation of the envelope glycoprotein S from Furin enables the invasion and replication of the virus virtually within the entire body, since this cellular protease is ubiquitously expressed. Here, we analyzed the naturally occurring variation of the amino acids sequence around the cleavage site of S. We found that the virus grossly mutates preferentially at P positions, resulting in single residue replacements that associate with gain-of-function phenotypes in specific conditions. Interestingly, some combinations of amino acids are absent, despite the evidence supporting some cleavability of the respective synthetic surrogates. In any case, the polybasic signature is maintained and, as a consequence, Furin dependence is preserved. Thus, no escape variants to Furin are observed in the population. Overall, the SARS-CoV-2 system per se represents an outstanding example of the evolution of substrate-enzyme interaction, demonstrating a fast-tracked optimization of a protein stretch towards the Furin catalytic pocket. Ultimately, these data disclose important information for the development of drugs targeting Furin and Furin-dependent pathogens.
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Affiliation(s)
- Leonardo Cassari
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy
| | - Angela Pavan
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy
| | - Giulia Zoia
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy
| | - Monica Chinellato
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy
| | - Elena Zeni
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy
| | - Alessandro Grinzato
- European Synchrotron Radiation Facility, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Sylvia Rothenberger
- Institute of Microbiology, University Hospital Center and University of Lausanne, Rue du Bugnon 48, 1011 Lausanne, Switzerland
- Spiez Laboratory, Federal Office for Civil Protection, Austrasse, 3700 Spiez, Switzerland
| | - Laura Cendron
- Department of Biology, University of Padua, Viale G. Colombo 3, 35131 Padova, Italy
| | - Monica Dettin
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy
| | - Antonella Pasquato
- Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy
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5
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Onoja A, Picchiotti N, Fallerini C, Baldassarri M, Fava F, Colombo F, Chiaromonte F, Renieri A, Furini S, Raimondi F. An explainable model of host genetic interactions linked to COVID-19 severity. Commun Biol 2022; 5:1133. [PMID: 36289370 PMCID: PMC9606365 DOI: 10.1038/s42003-022-04073-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 10/05/2022] [Indexed: 11/25/2022] Open
Abstract
We employed a multifaceted computational strategy to identify the genetic factors contributing to increased risk of severe COVID-19 infection from a Whole Exome Sequencing (WES) dataset of a cohort of 2000 Italian patients. We coupled a stratified k-fold screening, to rank variants more associated with severity, with the training of multiple supervised classifiers, to predict severity based on screened features. Feature importance analysis from tree-based models allowed us to identify 16 variants with the highest support which, together with age and gender covariates, were found to be most predictive of COVID-19 severity. When tested on a follow-up cohort, our ensemble of models predicted severity with high accuracy (ACC = 81.88%; AUCROC = 96%; MCC = 61.55%). Our model recapitulated a vast literature of emerging molecular mechanisms and genetic factors linked to COVID-19 response and extends previous landmark Genome-Wide Association Studies (GWAS). It revealed a network of interplaying genetic signatures converging on established immune system and inflammatory processes linked to viral infection response. It also identified additional processes cross-talking with immune pathways, such as GPCR signaling, which might offer additional opportunities for therapeutic intervention and patient stratification. Publicly available PheWAS datasets revealed that several variants were significantly associated with phenotypic traits such as "Respiratory or thoracic disease", supporting their link with COVID-19 severity outcome.
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Affiliation(s)
- Anthony Onoja
- Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy
| | - Nicola Picchiotti
- University of Siena, DIISM-SAILAB, Siena, Italy
- Department of Mathematics, University of Pavia, Pavia, Italy
| | - Chiara Fallerini
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Medical Genetics, University of Siena, Siena, Italy
| | - Margherita Baldassarri
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Medical Genetics, University of Siena, Siena, Italy
| | - Francesca Fava
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Medical Genetics, University of Siena, Siena, Italy
- Genetica Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Francesca Colombo
- Istituto di Tecnologie Biomediche-Consiglio Nazionale delle Ricerche, Segrate, MI, Italy
| | - Francesca Chiaromonte
- Dept. of Statistics and Huck Institutes of the Life Sciences, Penn State University, University Park, PA, 16802, USA
- Institute of Economics and EMbeDS, Sant'Anna School of Advanced Studies, 56127, Pisa, Italy
| | - Alessandra Renieri
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy.
- Medical Genetics, University of Siena, Siena, Italy.
- Genetica Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy.
| | - Simone Furini
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
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Abstract
The HIV Env glycoprotein is the surface glycoprotein responsible for viral entry into CD4+ immune cells. During infection, Env also serves as a primary target for antibody responses, which are robust but unable to control virus replication. Immune evasion by HIV-1 Env appears to employ complex mechanisms to regulate what antigenic states are presented to the immune system. Immunodominant features appear to be distinct from epitopes that interfere with Env functions in mediating infection. Further, cell-cell transmission studies indicate that vulnerable conformational states are additionally hidden from recognition on infected cells, even though the presence of Env at the cell surface is required for viral infection through the virological synapse. Cell-cell infection studies support that Env on infected cells is presented in distinct conformations from that on virus particles. Here we review data regarding the regulation of conformational states of Env and assess how regulated sorting of Env within the infected cell may underlie mechanisms to distinguish Env on the surface of virus particles versus Env on the surface of infected cells. These mechanisms may allow infected cells to avoid opsonization, providing cell-to-cell infection by HIV with a selective advantage during evolution within an infected individual. Understanding how distinct Env conformations are presented on cells versus viruses may be essential to designing effective vaccine approaches and therapeutic strategies to clear infected cell reservoirs.
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Affiliation(s)
- Connie Zhao
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Hongru Li
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Talia H. Swartz
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Benjamin K. Chen
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Prévost J, Medjahed H, Vézina D, Chen HC, Hahn BH, Smith AB, Finzi A. HIV-1 Envelope Glycoproteins Proteolytic Cleavage Protects Infected Cells from ADCC Mediated by Plasma from Infected Individuals. Viruses 2021; 13:2236. [PMID: 34835042 PMCID: PMC8625184 DOI: 10.3390/v13112236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) is synthesized in the endoplasmic reticulum as a trimeric gp160 precursor, which requires proteolytic cleavage by a cellular furin protease to mediate virus-cell fusion. Env is conformationally flexible but controls its transition from the unbound "closed" conformation (State 1) to downstream CD4-bound conformations (States 2/3), which are required for fusion. In particular, HIV-1 has evolved several mechanisms that reduce the premature "opening" of Env which exposes highly conserved epitopes recognized by non-neutralizing antibodies (nnAbs) capable of mediating antibody-dependent cellular cytotoxicity (ADCC). Env cleavage decreases its conformational transitions favoring the adoption of the "closed" conformation. Here we altered the gp160 furin cleavage site to impair Env cleavage and to examine its impact on ADCC responses mediated by plasma from HIV-1-infected individuals. We found that infected primary CD4+ T cells expressing uncleaved, but not wildtype, Env are efficiently recognized by nnAbs and become highly susceptible to ADCC responses mediated by plasma from HIV-1-infected individuals. Thus, HIV-1 limits the exposure of uncleaved Env at the surface of HIV-1-infected cells at least in part to escape ADCC responses.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Halima Medjahed
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA;
| | - Amos B. Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
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8
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Coutard B, Valle C, de Lamballerie X, Canard B, Seidah NG, Decroly E. The spike glycoprotein of the new coronavirus 2019-nCoV contains a furin-like cleavage site absent in CoV of the same clade. Antiviral Res 2020; 176:104742. [PMID: 32057769 PMCID: PMC7114094 DOI: 10.1016/j.antiviral.2020.104742] [Citation(s) in RCA: 1194] [Impact Index Per Article: 298.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 02/06/2023]
Abstract
In 2019, a new coronavirus (2019-nCoV) infecting Humans has emerged in Wuhan, China. Its genome has been sequenced and the genomic information promptly released. Despite a high similarity with the genome sequence of SARS-CoV and SARS-like CoVs, we identified a peculiar furin-like cleavage site in the Spike protein of the 2019-nCoV, lacking in the other SARS-like CoVs. In this article, we discuss the possible functional consequences of this cleavage site in the viral cycle, pathogenicity and its potential implication in the development of antivirals. The genomic sequence of 2019-nCoV indicates that the virus clusters with betacoronaviruses of lineage b. 2019-nCoV S-protein sequence has a specific furin-like cleavage site absent in lineage b CoV including SARS-CoV sequences. The furin-like cleavage site in the S-protein of 2019-nCoV may have implications for the viral life cycle and pathogenicity. Campaigns to develop anti-2019-nCoV therapeutics should include the evaluation of furin inhibitors.
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Affiliation(s)
- B Coutard
- Unité des Virus Émergents (UVE: Aix-Marseille Univ - IRD 190 - Inserm 1207 - IHU Méditerranée Infection), Marseille, France
| | - C Valle
- Aix Marseille Université, CNRS, AFMB UMR 7257, Marseille, France
| | - X de Lamballerie
- Unité des Virus Émergents (UVE: Aix-Marseille Univ - IRD 190 - Inserm 1207 - IHU Méditerranée Infection), Marseille, France
| | - B Canard
- Aix Marseille Université, CNRS, AFMB UMR 7257, Marseille, France
| | - N G Seidah
- Laboratory of Biochemical Neuroendocrinology, Montreal Clinical Research Institute (IRCM, Affiliated to the University of Montreal), 110 Pine Ave West, Montreal, QC, H2W1R7, Canada
| | - E Decroly
- Aix Marseille Université, CNRS, AFMB UMR 7257, Marseille, France.
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9
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Margolin E, Chapman R, Williamson A, Rybicki EP, Meyers AE. Production of complex viral glycoproteins in plants as vaccine immunogens. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1531-1545. [PMID: 29890031 PMCID: PMC6097131 DOI: 10.1111/pbi.12963] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 05/19/2023]
Abstract
Plant molecular farming offers a cost-effective and scalable approach to the expression of recombinant proteins which has been proposed as an alternative to conventional production platforms for developing countries. In recent years, numerous proofs of concept have established that plants can produce biologically active recombinant proteins and immunologically relevant vaccine antigens that are comparable to those made in conventional expression systems. Driving many of these advances is the remarkable plasticity of the plant proteome which enables extensive engineering of the host cell, as well as the development of improved expression vectors facilitating higher levels of protein production. To date, the only plant-derived viral glycoprotein to be tested in humans is the influenza haemagglutinin which expresses at ~50 mg/kg. However, many other viral glycoproteins that have potential as vaccine immunogens only accumulate at low levels in planta. A critical consideration for the production of many of these proteins in heterologous expression systems is the complexity of post-translational modifications, such as control of folding, glycosylation and disulphide bridging, which is required to reproduce the native glycoprotein structure. In this review, we will address potential shortcomings of plant expression systems and discuss strategies to optimally exploit the technology for the production of immunologically relevant and structurally authentic glycoproteins for use as vaccine immunogens.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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10
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Molecular Architecture of the Cleavage-Dependent Mannose Patch on a Soluble HIV-1 Envelope Glycoprotein Trimer. J Virol 2017; 91:JVI.01894-16. [PMID: 27807235 DOI: 10.1128/jvi.01894-16] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/25/2016] [Indexed: 01/04/2023] Open
Abstract
The formation of a correctly folded and natively glycosylated HIV-1 viral spike is dependent on protease cleavage of the gp160 precursor protein in the Golgi apparatus. Cleavage induces a compact structure which not only renders the spike capable of fusion but also limits further maturation of its extensive glycosylation. The redirection of the glycosylation pathway to preserve underprocessed oligomannose-type glycans is an important feature in immunogen design, as glycans contribute to or influence the epitopes of numerous broadly neutralizing antibodies. Here we present a quantitative site-specific analysis of a recombinant, trimeric mimic of the native HIV-1 viral spike (BG505 SOSIP.664) compared to the corresponding uncleaved pseudotrimer and the matched gp120 monomer. We present a detailed molecular map of a trimer-associated glycan remodeling that forms a localized subdomain of the native mannose patch. The formation of native trimers is a critical design feature in shaping the glycan epitopes presented on recombinant vaccine candidates. IMPORTANCE The envelope spike of human immunodeficiency virus type 1 (HIV-1) is a target for antibody-based neutralization. For some patients infected with HIV-1, highly potent antibodies have been isolated that can neutralize a wide range of circulating viruses. It is a goal of HIV-1 vaccine research to elicit these antibodies by immunization with recombinant mimics of the viral spike. These antibodies have evolved to recognize the dense array of glycans that coat the surface of the viral molecule. We show how the structure of these glycans is shaped by steric constraints imposed upon them by the native folding of the viral spike. This information is important in guiding the development of vaccine candidates.
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11
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Neuroinflammation-Induced Interactions between Protease-Activated Receptor 1 and Proprotein Convertases in HIV-Associated Neurocognitive Disorder. Mol Cell Biol 2015; 35:3684-700. [PMID: 26283733 DOI: 10.1128/mcb.00764-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/11/2015] [Indexed: 01/31/2023] Open
Abstract
The proprotein convertases (PCs) furin, PC5, PACE4, and PC7 cleave secretory proteins after basic residues, including the HIV envelope glycoprotein (gp160) and Vpr. We evaluated the abundance of PC mRNAs in postmortem brains of individuals exhibiting HIV-associated neurocognitive disorder (HAND), likely driven by neuroinflammation and neurotoxic HIV proteins (e.g., envelope and Vpr). Concomitant with increased inflammation-related gene expression (interleukin-1β [IL-1β]), the mRNA levels of the above PCs are significantly increased, together with those of the proteinase-activated receptor 1 (PAR1), an inflammation-associated receptor that is cleaved by thrombin at ProArg41↓ (where the down arrow indicates the cleavage location), and potentially by PCs at Arg41XXXXArg46↓. The latter motif in PAR1, but not its R46A mutant, drives its interactions with PCs. Indeed, PAR1 upregulation leads to the inhibition of membrane-bound furin, PC5B, and PC7 and inhibits gp160 processing and HIV infectivity. Additionally, a proximity ligation assay revealed that furin and PC7 interact with PAR1. Reciprocally, increased furin expression reduces the plasma membrane abundance of PAR1 by trapping it in the trans-Golgi network. Furthermore, soluble PC5A/PACE4 can target/disarm cell surface PAR1 through cleavage at Arg46↓. PACE4/PC5A decreased calcium mobilization induced by thrombin stimulation. Our data reveal a new PC-PAR1-interaction pathway, which offsets the effects of HIV-induced neuroinflammation, viral infection, and potentially the development of HAND.
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12
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Ho H, Li Y, Nie G. Inhibition of embryo implantation in mice through vaginal administration of a proprotein convertase 6 inhibitor. Reprod Biol 2014; 14:155-9. [PMID: 24856475 DOI: 10.1016/j.repbio.2013.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 12/24/2013] [Indexed: 11/29/2022]
Abstract
Uterine proprotein convertase 6 (PC6) plays a critical role in embryo implantation in both mice and women. It was hypothesized that inhibiting uterine PC6 could prevent pregnancy. Vaginal administration of a PC6 inhibitor presents the ideal route for local drug delivery. A peptide-based PC6 inhibitor, C-30k-PEG Poly R that was previously shown to have properties of increased vaginal absorption and penetration was tested for its contraceptive potential in mice following vaginal administration. The study demonstrated that this approach could inhibit embryo implantation in some mice (24% completely and 47% partially inhibited).
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Affiliation(s)
- Huiting Ho
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia
| | - Ying Li
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
| | - Guiying Nie
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia.
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13
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Aiamkitsumrit B, Dampier W, Antell G, Rivera N, Martin-Garcia J, Pirrone V, Nonnemacher MR, Wigdahl B. Bioinformatic analysis of HIV-1 entry and pathogenesis. Curr HIV Res 2014; 12:132-61. [PMID: 24862329 PMCID: PMC4382797 DOI: 10.2174/1570162x12666140526121746] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/18/2014] [Accepted: 05/06/2014] [Indexed: 02/07/2023]
Abstract
The evolution of human immunodeficiency virus type 1 (HIV-1) with respect to co-receptor utilization has been shown to be relevant to HIV-1 pathogenesis and disease. The CCR5-utilizing (R5) virus has been shown to be important in the very early stages of transmission and highly prevalent during asymptomatic infection and chronic disease. In addition, the R5 virus has been proposed to be involved in neuroinvasion and central nervous system (CNS) disease. In contrast, the CXCR4-utilizing (X4) virus is more prevalent during the course of disease progression and concurrent with the loss of CD4(+) T cells. The dual-tropic virus is able to utilize both co-receptors (CXCR4 and CCR5) and has been thought to represent an intermediate transitional virus that possesses properties of both X4 and R5 viruses that can be encountered at many stages of disease. The use of computational tools and bioinformatic approaches in the prediction of HIV-1 co-receptor usage has been growing in importance with respect to understanding HIV-1 pathogenesis and disease, developing diagnostic tools, and improving the efficacy of therapeutic strategies focused on blocking viral entry. Current strategies have enhanced the sensitivity, specificity, and reproducibility relative to the prediction of co-receptor use; however, these technologies need to be improved with respect to their efficient and accurate use across the HIV-1 subtypes. The most effective approach may center on the combined use of different algorithms involving sequences within and outside of the env-V3 loop. This review focuses on the HIV-1 entry process and on co-receptor utilization, including bioinformatic tools utilized in the prediction of co-receptor usage. It also provides novel preliminary analyses for enabling identification of linkages between amino acids in V3 with other components of the HIV-1 genome and demonstrates that these linkages are different between X4 and R5 viruses.
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Affiliation(s)
| | | | | | | | | | | | | | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA 19102.
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14
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Ho H, Singh H, Heng S, Nero TL, Paule S, Parker MW, Johnson AT, Jiao GS, Nie G. Small molecule proprotein convertase inhibitors for inhibition of embryo implantation. PLoS One 2013; 8:e81380. [PMID: 24324690 PMCID: PMC3852413 DOI: 10.1371/journal.pone.0081380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 10/14/2013] [Indexed: 11/19/2022] Open
Abstract
Uterine proprotein convertase (PC) 6 plays a critical role in embryo implantation and is pivotal for pregnancy establishment. Inhibition of PC6 may provide a novel approach for the development of non-hormonal and female-controlled contraceptives. We investigated a class of five synthetic non-peptidic small molecule compounds that were previously reported as potent inhibitors of furin, another PC member. We examined (i) the potency of these compounds in inhibiting PC6 activity in vitro; (ii) their binding modes in the PC6 active site in silico; (iii) their efficacy in inhibiting PC6-dependent cellular processes essential for embryo implantation using human cell-based models. All five compounds showed potent inhibition of PC6 activity in vitro, and in silico docking demonstrated that these inhibitors could adopt a similar binding mode in the PC6 active site. However, when these compounds were tested for their inhibition of decidualization of primary human endometrial stromal cells, a PC6-dependent cellular process critical for embryo implantation, only one (compound 1o) showed potent inhibition. The lack of activity in the cell-based assay may reflect the inability of the compounds to penetrate the cell membrane. Because compound's lipophilicity is linked to cell penetration, a measurement of lipophilicity (logP) was calculated for each compound. Compound 1o is unique as it appears the most lipophilic among the five compounds. Compound 1o also inhibited another crucial PC6-dependent process, the attachment of human trophoblast spheroids to endometrial epithelial cells (a model for human embryo attachment). We thus identified compound 1o as a potent small molecule PC6 inhibitor with pharmaceutical potential to inhibit embryo implantation. Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates. Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug.
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Affiliation(s)
- Huiting Ho
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Harmeet Singh
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
| | - Sophea Heng
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Tracy L. Nero
- Biota Structural Biology Laboratory and ACRF Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Sarah Paule
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
| | - Michael W. Parker
- Biota Structural Biology Laboratory and ACRF Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Alan T. Johnson
- Department of Chemistry, PanThera Biopharma LLC, Aiea, Hawaii, United States of America
| | - Guan-Sheng Jiao
- Department of Chemistry, PanThera Biopharma LLC, Aiea, Hawaii, United States of America
- * E-mail: (GN); (GSJ)
| | - Guiying Nie
- Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (GN); (GSJ)
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15
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Hipp MM, Shepherd D, Gileadi U, Aichinger MC, Kessler BM, Edelmann MJ, Essalmani R, Seidah NG, Reis e Sousa C, Cerundolo V. Processing of human toll-like receptor 7 by furin-like proprotein convertases is required for its accumulation and activity in endosomes. Immunity 2013; 39:711-21. [PMID: 24138882 PMCID: PMC4839496 DOI: 10.1016/j.immuni.2013.09.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 07/25/2013] [Indexed: 11/18/2022]
Abstract
Toll-like receptor 7 (TLR7) triggers antiviral immune responses by recognizing viral single-stranded RNA in endosomes, but the biosynthetic pathway of human TLR7 (hTLR7) remains unclear. Here, we show that hTLR7 is proteolytically processed and that the C-terminal fragment selectively accumulates in endocytic compartments. hTLR7 processing occurred at neutral pH and was dependent on furin-like proprotein convertases (PCs). Furthermore, TLR7 processing was required for its functional response to TLR7 agonists such as R837 or influenza virus. Notably, proinflammatory and differentiation stimuli increased the expression of furin-like PCs in immune cells, suggesting a positive feedback mechanism for TLR7 processing during infection. Because self-RNA can under certain conditions activate TLR7 and trigger autoimmunity, our results identify furin-like PCs as a possible target to attenuate TLR7-dependent autoimmunity and other immune pathologies.
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Affiliation(s)
- Madeleine M Hipp
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DU, UK
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16
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Kato S, Zhang R, Roberts JD. Proprotein convertases play an important role in regulating PKGI endoproteolytic cleavage and nuclear transport. Am J Physiol Lung Cell Mol Physiol 2013; 305:L130-40. [PMID: 23686857 PMCID: PMC3726948 DOI: 10.1152/ajplung.00391.2012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 05/15/2013] [Indexed: 12/27/2022] Open
Abstract
Nitric oxide and cGMP modulate vascular smooth muscle cell (SMC) phenotype by regulating cell differentiation and proliferation. Recent studies suggest that cGMP-dependent protein kinase I (PKGI) cleavage and the nuclear translocation of a constitutively active kinase fragment, PKGIγ, are required for nuclear cGMP signaling in SMC. However, the mechanisms that control PKGI proteolysis are unknown. Inspection of the amino acid sequence of a PKGI cleavage site that yields PKGIγ and a protease database revealed a putative minimum consensus sequence for proprotein convertases (PCs). Therefore we investigated the role of PCs in regulating PKGI proteolysis. We observed that overexpression of PCs, furin and PC5, but not PC7, which are all expressed in SMC, increase PKGI cleavage in a dose-dependent manner in human embryonic kidney (HEK) 293 cells. Moreover, furin-induced proteolysis of mutant PKGI, in which alanines were substituted into the putative PC consensus sequence, was decreased in these cells. In addition, overexpression of furin increased PKGI proteolysis in LoVo cells, which is an adenocarcinoma cell line expressing defective furin without PC activity. Also, expression of α1-PDX, an engineered serpin-like PC inhibitor, reduced PC activity and decreased PKGI proteolysis in HEK293 cells. Last, treatment of low-passage rat aortic SMC with membrane-permeable PC inhibitor peptides decreased cGMP-stimulated nuclear PKGIγ translocation. These data indicate for the first time that PCs have a role in regulating PKGI proteolysis and the nuclear localization of its active cleavage product, which are important for cGMP-mediated SMC phenotype.
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Affiliation(s)
- Shin Kato
- Cardiovascular Research Center of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
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17
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Chereshnev VA, Bocharov G, Bazhan S, Bachmetyev B, Gainova I, Likhoshvai V, Argilaguet JM, Martinez JP, Rump JA, Mothe B, Brander C, Meyerhans A. Pathogenesis and treatment of HIV infection: the cellular, the immune system and the neuroendocrine systems perspective. Int Rev Immunol 2013; 32:282-306. [PMID: 23617796 DOI: 10.3109/08830185.2013.779375] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Infections with HIV represent a great challenge for the development of strategies for an effective cure. The spectrum of diseases associated with HIV ranges from opportunistic infections and cancers to systemic physiological disorders like encephalopathy and neurocognitive impairment. A major progress in controlling HIV infection has been achieved by highly active antiretroviral therapy (HAART). However, HAART does neither eliminate the virus reservoirs in form of latently infected cells nor does it completely reconstitute immune reactivity and physiological status. Furthermore, the failure of the STEP vaccine trial and the only marginal efficacies of the RV144 trial together suggest that the causal relationships between the complex sets of viral and immunological processes that contribute to protection or disease pathogenesis are still poorly understood. Here, we provide an up-to-date overview of HIV-host interactions at the cellular, the immune system and the neuroendocrine systems level. Only by integrating this multi-level knowledge one will be able to handle the systems complexity and develop new methodologies of analysis and prediction for a functional restoration of the immune system and the health of the infected host.
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Affiliation(s)
- V A Chereshnev
- Institute of Immunology and Physiology, Ural Branch RAS, Ekaterinburg, Russia.
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18
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Ho H, Nero TL, Singh H, Parker MW, Nie G. PEGylation of a proprotein convertase peptide inhibitor for vaginal route of drug delivery: in vitro bioactivity, stability and in vivo pharmacokinetics. Peptides 2012; 38:266-74. [PMID: 23000303 DOI: 10.1016/j.peptides.2012.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 01/27/2023]
Abstract
Uterine proprotein convertase (PC) 6 is critical for embryo implantation in mice and women. It is also one of the PC family members that play a vital role in HIV infectivity. We hypothesized that inhibiting PC6 in the female reproductive tract (vagina, cervix and uterus), may protect women from both pregnancy and HIV infection. One key requirement to prove this concept in an animal model is a vaginally deliverable PC6 inhibitor. Nona-D-arginine (Poly R) is a potent peptide PC inhibitor and is able to inhibit HIV in cell culture. We modified Poly R by PEGylation with different strategies and determined their biochemical properties in vitro and in vivo. PEGylation at the C-terminus, regardless of the PEG size (30 kDa or 1239 Da) did not compromise the inhibitory potency of Poly R. In contrast, PEGylation at both termini (1239 Da) dramatically reduced its inhibitory activity. Poly R and C-PEGylated Poly Rs also showed equal potency in inhibiting a PC6-dependent cellular process critical for embryo implantation. Poly R and the equipotent C-PEGylated Poly Rs were further tested for their serum stability in vitro and pharmacokinetics in vivo following vaginal administration in mice. All Poly Rs were equally stable in mouse serum in vitro for 24h; C-PEGylated Poly Rs showed enhanced vaginal absorption and penetration across the vaginal mucosa/epithelium. This is the first report that C-terminal PEGylation significantly enhances the therapeutic properties of Poly R for vaginal drug delivery. Our findings also provide important insights into future design of Poly R derivatives.
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Affiliation(s)
- Huiting Ho
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
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19
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Inhibition of proprotein convertase 5/6 activity: potential for nonhormonal women-centered contraception. Contraception 2011; 85:602-10. [PMID: 22079608 DOI: 10.1016/j.contraception.2011.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 10/04/2011] [Accepted: 10/05/2011] [Indexed: 11/22/2022]
Abstract
BACKGROUND Proprotein convertase 5/6 (PC6) is critical for endometrial epithelial receptivity and stromal cell decidualization for embryo implantation in women. We hypothesized that inhibiting PC6 could block implantation for contraception. The aim of this study was to prove this concept using human cell models and rabbits. STUDY DESIGN A potential PC6 inhibitor, C1239-PEG-Poly R, was biochemically confirmed to be a potent PC6 inhibitor. The potential contraceptive action of the inhibitor was then tested in decidualization of primary human endometrial stromal cells in a human trophoblast spheroid attachment model and in vivo in rabbits. RESULTS The PC6 inhibitor C1239-PEG-Poly R inhibited in a dose-dependent manner both decidualization and spheroid attachment. Vaginal delivery of 200 μL of the inhibitor at a final concentration of 5 mM to rabbits over a 3-day period starting 6 days after mating resulted in a 60% decrease in implantation and, hence, pregnancy. CONCLUSIONS This study presents proof of concept that PC6 inhibition has the potential to block embryo implantation, providing nonhormonal contraception for women.
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20
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Susan-Resiga D, Essalmani R, Hamelin J, Asselin MC, Benjannet S, Chamberland A, Day R, Szumska D, Constam D, Bhattacharya S, Prat A, Seidah NG. Furin is the major processing enzyme of the cardiac-specific growth factor bone morphogenetic protein 10. J Biol Chem 2011; 286:22785-94. [PMID: 21550985 DOI: 10.1074/jbc.m111.233577] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bone morphogenetic protein 10 (BMP10) is a member of the TGF-β superfamily and plays a critical role in heart development. In the postnatal heart, BMP10 is restricted to the right atrium. The inactive pro-BMP10 (∼60 kDa) is processed into active BMP10 (∼14 kDa) by an unknown protease. Proteolytic cleavage occurs at the RIRR(316)↓ site (human), suggesting the involvement of proprotein convertase(s) (PCs). In vitro digestion of a 12-mer peptide encompassing the predicted cleavage site with furin, PACE4, PC5/6, and PC7, showed that furin cleaves the best, whereas PC7 is inactive on this peptide. Ex vivo studies in COS-1 cells, a cell line lacking PC5/6, revealed efficient processing of pro-BMP10 by endogenous PCs other than PC5/6. The lack of processing of overexpressed pro-BMP10 in the furin- and PACE4-deficient cell line, CHO-FD11, and in furin-deficient LoVo cells, was restored by stable (CHO-FD11/Fur cells) or transient (LoVo cells) expression of furin. Use of cell-permeable and cell surface inhibitors suggested that endogenous PCs process pro-BMP10 mostly intracellularly, but also at the cell surface. Ex vivo experiments in mouse primary hepatocytes (wild type, PC5/6 knock-out, and furin knock-out) corroborated the above findings that pro-BMP10 is a substrate for endogenous furin. Western blot analyses of heart right atria extracts from wild type and PACE4 knock-out adult mice showed no significant difference in the processing of pro-BMP10, implying no in vivo role of PACE4. Overall, our in vitro, ex vivo, and in vivo data suggest that furin is the major convertase responsible for the generation of BMP10.
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Affiliation(s)
- Delia Susan-Resiga
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Université de Montréal, Montreal, Quebec H2W 1R7, Canada
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21
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Rousselet E, Benjannet S, Hamelin J, Canuel M, Seidah NG. The proprotein convertase PC7: unique zymogen activation and trafficking pathways. J Biol Chem 2011; 286:2728-38. [PMID: 21075846 PMCID: PMC3024769 DOI: 10.1074/jbc.m110.192344] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 11/09/2010] [Indexed: 01/04/2023] Open
Abstract
The zymogen activation mechanism and physiological functions of the most ancient and highly conserved basic amino acid-specific proprotein convertase 7 (PC7) are not known. Herein, we characterized the biosynthesis, subcellular localization, and trafficking of the membrane-bound full-length rat and human PC7. The prosegment of PC7 is primarily secreted alone as a non-inhibitory protein via the conventional, Golgi-dependent, secretory pathway. Mature PC7 is partially sulfated and thus reaches the cell surface via the conventional route. However, a fraction of PC7 reaches the cell surface through a brefeldin A- and COPII-independent unconventional secretory pathway. The latter trafficking may explain the rapid (<10 min) transit of a fraction of PC7 from the ER to the cell surface. Electron microscopy further confirmed the localization of PC7 to the cell surface of HEK293 cells. Within the cytosolic tail, only two cysteines (Cys(699) and Cys(704)) are palmitoylated, but this modification does not affect the choice of trafficking pathway. Swapping the transmembrane-cytosolic tail (TMCT) sequences of the convertases Furin and PC7 revealed that PC7(TMCT-Furin) is much more sulfated and hence traffics more efficiently through the conventional secretory pathway. In contrast, the Furin(TMCT-PC7) is no longer sulfated and thus reaches the cell surface by the unconventional pathway. Because trafficking of PC7(CT-Furin) and Furin(CT-PC7) resemble their wild type counterparts, we deduce that the transmembrane domain of PC7 regulates the sorting of PC7 toward the unconventional secretory pathway. In conclusion, PC7 is distinct from other proprotein convertases in its zymogen activation, subcellular localization, and trafficking.
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Affiliation(s)
- Estelle Rousselet
- From the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Suzanne Benjannet
- From the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Josée Hamelin
- From the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Maryssa Canuel
- From the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Nabil G. Seidah
- From the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
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22
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Rousselet E, Benjannet S, Marcinkiewicz E, Asselin MC, Lazure C, Seidah NG. Proprotein convertase PC7 enhances the activation of the EGF receptor pathway through processing of the EGF precursor. J Biol Chem 2011; 286:9185-95. [PMID: 21209099 DOI: 10.1074/jbc.m110.189936] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Although the processing profile of the membrane-bound epidermal growth factor precursor (pro-EGF) is tissue-specific, it has not been investigated at the cellular level nor have the cognate proteinases been defined. Among the proprotein convertases (PCs), only the membrane-bound PC7, the most ancient and conserved basic amino acid-specific PC family member, induces the processing of pro-EGF into an ∼115-kDa transmembrane form (EGF-115) at an unusual VHPR(290)↓A motif. Because site-directed mutagenesis revealed that Arg(290) is not critical, the generation of EGF-115 by PC7 is likely indirect. This was confirmed by testing a wide range of protease inhibitors, which revealed that the production of EGF-115 is most probably achieved via the activation by PC7 of a latent serine and/or cysteine protease(s). EGF-115 is more abundant at the cell surface than pro-EGF and is associated with a stronger EGF receptor (EGFR) activation, as evidenced by higher levels of phosphorylated ERK1/2. This suggests that the generation of EGF-115 represents a regulatory mechanism of juxtacrine EGFR activation. Thus, PC7 is distinct from the other PCs in its ability to enhance the activation of the cell surface EGFR.
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Affiliation(s)
- Estelle Rousselet
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
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23
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Abstract
Enveloped viruses penetrate their cell targets following the merging of their membrane with that of the cell. This fusion process is catalyzed by one or several viral glycoproteins incorporated on the membrane of the virus. These envelope glycoproteins (EnvGP) evolved in order to combine two features. First, they acquired a domain to bind to a specific cellular protein, named "receptor." Second, they developed, with the help of cellular proteins, a function of finely controlled fusion to optimize the replication and preserve the integrity of the cell, specific to the genus of the virus. Following the activation of the EnvGP either by binding to their receptors and/or sometimes the acid pH of the endosomes, many changes of conformation permit ultimately the action of a specific hydrophobic domain, the fusion peptide, which destabilizes the cell membrane and leads to the opening of the lipidic membrane. The comprehension of these mechanisms is essential to develop medicines of the therapeutic class of entry inhibitor like enfuvirtide (Fuzeon) against human immunodeficiency virus (HIV). In this chapter, we will summarize the different envelope glycoprotein structures that viruses develop to achieve membrane fusion and the entry of the virus. We will describe the different entry pathways and cellular proteins that viruses have subverted to allow infection of the cell and the receptors that are used. Finally, we will illustrate more precisely the recent discoveries that have been made within the field of the entry process, with a focus on the use of pseudoparticles. These pseudoparticles are suitable for high-throughput screenings that help in the development of natural or artificial inhibitors as new therapeutics of the class of entry inhibitors.
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Affiliation(s)
- François-Loic Cosset
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
| | - Dimitri Lavillette
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
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24
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Essalmani R, Susan-Resiga D, Chamberland A, Abifadel M, Creemers JW, Boileau C, Seidah NG, Prat A. In vivo evidence that furin from hepatocytes inactivates PCSK9. J Biol Chem 2010; 286:4257-63. [PMID: 21147780 DOI: 10.1074/jbc.m110.192104] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The proprotein convertase PCSK9 plays a key role in cholesterol homeostasis by binding the LDL receptor and targeting it toward degradation. PCSK9 is strongly expressed in the liver and is found in human and mouse plasma as mature (∼ 62 kDa) and inactivated (∼ 55 kDa) forms. Ex vivo data showed that human PCSK9 is inactivated by cleavage at Arg(218)↓ by the overexpressed convertases furin and PC5/6A. Analysis of the plasma of human heterozygotes for R218S and F216L mutations revealed a ∼ 50% reduction in the levels of the ∼ 55-kDa form. To identify the convertase(s) responsible for cleavage at Arg(218) in vivo, we inactivated the genes of furin and/or PC5/6 specifically in hepatocytes. The PCSK9-inactivated form was strongly reduced in mice lacking furin in hepatocytes (Fur-hKO) and only slightly reduced in PC5/6-hKO plasma. In agreement with a key role of furin in regulating PCSK9 activity in vivo, we observed an overall 26% drop in the LDL receptor protein levels of Fur-hKO livers, likely due to the compound effects of a 35% increase in PCSK9 mRNA levels and the loss of PCSK9 cleavage, suggesting a higher activity of PCSK9 in these mice. Overexpression of PCSK9 in primary hepatocytes obtained from these mice revealed that only full-length, membrane-bound, but not soluble, furin is the cognate convertase. We conclude that in hepatocytes furin regulates PCSK9 mRNA levels and is the key in vivo-inactivating protease of circulating PCSK9.
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Affiliation(s)
- Rachid Essalmani
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
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25
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Furin targeted drug delivery for treatment of rhabdomyosarcoma in a mouse model. PLoS One 2010; 5:e10445. [PMID: 20454619 PMCID: PMC2862740 DOI: 10.1371/journal.pone.0010445] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 04/01/2010] [Indexed: 01/01/2023] Open
Abstract
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Improvement of treatment efficacy and decreased side effects through tumor-targeted drug delivery would be desirable. By panning with a phage-displayed cyclic random peptide library we selected a peptide with strong affinity for RMS in vitro and in vivo. The peptide minimal binding motif Arg-X-(Arg/Lys)(Arg/Lys) identified by alanine-scan, suggested the target receptor to be a proprotein convertase (PC). Expression profiling of all PCs in RMS biopsies and cell lines revealed consistent high expression levels for the membrane-bound furin and PC7. Direct binding of RMS-P3 peptide to furin was demonstrated by affinity chromatography and supported by activity and colocalization studies. Treatment of RMS in mice with doxorubicin coupled to the targeting peptide resulted in a two-fold increase in therapeutic efficacy compared to doxorubicin treatment alone. Our findings indicate surface-furin binding as novel mechanism for therapeutic cell penetration which needs to be further investigated. Furthermore, this work demonstrates that specific targeting of membrane-bound furin in tumors is possible for and suggests that RMS and other tumors might benefit from proprotein convertases targeted drug delivery.
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Kilpatrick LM, Stephens AN, Hardman BM, Salamonsen LA, Li Y, Stanton PG, Nie G. Proteomic Identification of Caldesmon as a Physiological Substrate of Proprotein Convertase 6 in Human Uterine Decidual Cells Essential for Pregnancy Establishment. J Proteome Res 2009; 8:4983-92. [DOI: 10.1021/pr900381a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Lynette M. Kilpatrick
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Andrew N. Stephens
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Belinda M. Hardman
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Lois A. Salamonsen
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Ying Li
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Peter G. Stanton
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
| | - Guiying Nie
- Prince Henry’s Institute of Medical Research, 246 Clayton Road, Clayton, Victoria, 3168, Australia
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27
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Chrétien M, Seidah NG, Basak A, Mbikay M. Proprotein convertases as therapeutic targets. Expert Opin Ther Targets 2008; 12:1289-300. [DOI: 10.1517/14728222.12.10.1289] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Ozden S, Lucas-Hourani M, Ceccaldi PE, Basak A, Valentine M, Benjannet S, Hamelin J, Jacob Y, Mamchaoui K, Mouly V, Desprès P, Gessain A, Butler-Browne G, Chrétien M, Tangy F, Vidalain PO, Seidah NG. Inhibition of Chikungunya Virus Infection in Cultured Human Muscle Cells by Furin Inhibitors. J Biol Chem 2008; 283:21899-908. [DOI: 10.1074/jbc.m802444200] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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29
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Pasquato A, Seidah NG. The H5N1 Influenza Variant Fujian-Like Hemagglutinin Selected Following Vaccination Exhibits a Compromised Furin Cleavage. J Mol Neurosci 2008; 35:339-43. [DOI: 10.1007/s12031-008-9052-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 02/07/2008] [Indexed: 12/01/2022]
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30
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Xiao Y, Chen G, Richard J, Rougeau N, Li H, Seidah NG, Cohen EA. Cell-surface processing of extracellular human immunodeficiency virus type 1 Vpr by proprotein convertases. Virology 2007; 372:384-97. [PMID: 18061232 DOI: 10.1016/j.virol.2007.10.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 09/27/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
Increasing evidence suggests that extracellular Vpr could contribute to HIV pathogenesis through its effect on bystander cells. Soluble forms of Vpr have been detected in the sera and cerebrospinal fluids of HIV-1-infected patients, and in vitro studies have implicated extracellular Vpr as an effector of cellular responses, including G2 arrest, apoptosis and induction of cytokines and chemokines production, presumably through its ability to transduce into multiple cell types. However, the mechanism underlying Vpr release from HIV-1-producing cells remains undefined and the biological modifications that the extracellular protein may undergo are largely unknown. We provide evidence indicating that soluble forms of Vpr are present in the extracellular medium of HIV-1-producing cells. Release of Vpr in the extracellular medium did not originate from decaying or disrupted HIV-1 virions that package Vpr but rather appeared associated with HIV-1-mediated cytopathicity. Interestingly, Vpr was found to undergo proteolytic processing at a very well conserved proprotein convertase (PC) cleavage site, R(85)QRR(88) downward arrow, located within the functionally important C-terminal arginine-rich domain of the protein. Vpr processing occurred extracellularly upon close contact to cells and most likely involved a cell surface-associated PC. Consistently, PC inhibitors suppressed Vpr processing, while expression of extracellular matrix-associated PC5 and PACE4 enhanced Vpr cleavage. PC-mediated processing of extracellular Vpr led to the production of a truncated Vpr product that was defective for the induction of cell cycle arrest and apoptosis when expressed in human cells. Collectively, these results suggest that cell surface processing of extracellular Vpr by PCs might regulate the levels of active soluble Vpr.
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Affiliation(s)
- Yong Xiao
- Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal, Montreal, Quebec, Canada
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31
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Bontemps Y, Scamuffa N, Calvo F, Khatib A. Potential opportunity in the development of new therapeutic agents based on endogenous and exogenous inhibitors of the proprotein convertases. Med Res Rev 2007; 27:631-48. [PMID: 17019676 PMCID: PMC7168524 DOI: 10.1002/med.20072] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The proprotein convertases (PCs) are responsible for the endoproteolytic processing of various protein precursors (e.g., growth factors, receptors, adhesion molecules, and matrix metalloproteinases) implicated in several diseases such as obesity, diabetes, atherosclerosis, cancer, and Alzheimer disease. The potential clinical and pharmacological role of the PCs has fostered the development of various PC‐inhibitors. In this review we summarized the recent findings on PCs inhibitors, their mode of actions and potential use in the therapy of various diseases. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 5, 631–648, 2007
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Affiliation(s)
- Yannick Bontemps
- INSERM, U 716, Equipe AVENIR, Institut de Génétique Moléculaire, Paris 75010, France
- Université Paris 7, Paris 75251, France
| | - Nathalie Scamuffa
- INSERM, U 716, Equipe AVENIR, Institut de Génétique Moléculaire, Paris 75010, France
- Université Paris 7, Paris 75251, France
| | - Fabien Calvo
- INSERM, U 716, Equipe AVENIR, Institut de Génétique Moléculaire, Paris 75010, France
- Université Paris 7, Paris 75251, France
| | - Abdel‐Majid Khatib
- INSERM, U 716, Equipe AVENIR, Institut de Génétique Moléculaire, Paris 75010, France
- Université Paris 7, Paris 75251, France
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32
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Lee SN, Kacprzak MM, Day R, Lindberg I. Processing and trafficking of a prohormone convertase 2 active site mutant. Biochem Biophys Res Commun 2007; 355:825-9. [PMID: 17320043 PMCID: PMC2040296 DOI: 10.1016/j.bbrc.2007.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 02/08/2007] [Indexed: 11/17/2022]
Abstract
Processing of most PC zymogens is required for successful folding and/or passage through the secretory pathway; active site mutants are retained in the ER and degraded. We here report that the active site serine mutant of PC2 (PC2-S383A) was efficiently secreted as the intact zymogen in CHO-K1 cells, suggesting that its propeptide can productively insert into the mutated binding pocket without causing misfolding. In AtT-20 cells, PC2-S383A was cleaved at the secondary cleavage site within the propeptide; this cleavage event was pH-dependent and was inhibited by a proprotein convertase inhibitor. In vitro digestion of PC2-S383A with various convertases indicates that this site is accessible to in trans cleavage. Abundant immunoreactive S383A PC2 was found in secretory granules, supporting the idea that this protein is efficiently trafficked through the secretory pathway.
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Affiliation(s)
- Sang-Nam Lee
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Magdalena M. Kacprzak
- Turku Centre for Biotechnology, Abo Akademi and Turku University, Turku FIN-20521, Finland
| | - Robert Day
- Département de Pharmacologie, Faculté de Mèdecine et Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Québec, Canada JIH 5N4
| | - Iris Lindberg
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70112
- To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center/Research Institute for Children Children’s Hospital, 200 Henry Clay Ave, New Orleans, Louisiana, 70118, Tel: 504 896 2755, Fax: 504 896 9413, E-mail:
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33
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Pasquato A, Pullikotil P, Asselin MC, Vacatello M, Paolillo L, Ghezzo F, Basso F, Di Bello C, Dettin M, Seidah NG. The proprotein convertase SKI-1/S1P. In vitro analysis of Lassa virus glycoprotein-derived substrates and ex vivo validation of irreversible peptide inhibitors. J Biol Chem 2006; 281:23471-81. [PMID: 16790437 DOI: 10.1074/jbc.m513675200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Herein we designed, synthesized, tested, and validated fluorogenic methylcoumarinamide (MCA) and chloromethylketone-peptides spanning the Lassa virus GPC cleavage site as substrates and inhibitors for the proprotein convertase SKI-1/S1P. The 7-mer MCA (YISRRLL-MCA) and 8-mer MCA (IYISRRLL-MCA) are very efficiently cleaved with respect to both the 6-mer MCA (ISRRLL-MCA) and point mutated fluorogenic analogues, except for the 7-mer mutant Y253F. The importance of the P7 phenylic residue was confirmed by digestions of two 16-mer non-fluorogenic peptidyl substrates that differ by a single point mutation (Y253A). Because NMR analysis of these 16-mer peptides did not reveal significant structural differences at recognition motif RRLL, the P7 Tyr residue is likely important in establishing key interactions within the catalytic pocket of SKI-1. Based on these data, we established through analysis of pro-ATF6 and pro-SREBP-2 cellular processing that decanoylated chloromethylketone 7-mer, 6-mer, and 4-mer peptides containing the core RRLL sequence are irreversible and potent ex vivo SKI-1 inhibitors. Although caution must be exercised in using these inhibitors in in vitro reactions, as they can also inhibit the basic amino acid-specific convertase furin, within cells and when used at concentrations < or = 100 microM these inhibitors are relatively specific for inhibition of SKI-1 processing events, as opposed to those performed by furin-like convertases.
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Affiliation(s)
- Antonella Pasquato
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
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34
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Jiang W, Jin N, Cui S, Li Z, Zhang L, Zhang H, Wang H, Han W. Construction and characterization of recombinant fowlpox virus coexpressing HIV-1CN gp120 and IL-2. J Virol Methods 2005; 130:95-101. [PMID: 16029899 DOI: 10.1016/j.jviromet.2005.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 06/09/2005] [Accepted: 06/14/2005] [Indexed: 10/25/2022]
Abstract
The acquired immunodeficiency syndrome (AIDS) has now become one of the most serious infectious disease in the world, the safe and effective AIDS vaccines would be the best tools to control the disease. Fowlpox virus has been studied recently as a potential vector for the delivery of heterologous vaccine antigen. In this study, a recombinant fowlpox virus coexpressing gp120 of Chinese prevalent HIV-1 strain and IL-2 was constructed and the cellular immune responses against HIV-1 gp120 in BALB/c mice were evaluated. Chinese vaccine strain 282E4 of fowlpox virus was used as the vector to construct the recombinant fowlpox virus (rFPV) coexpressing HIV-1 gp120 and IL-2 via homologous recombination, and the recombinant virus was identified by PCR and Western blotting. The specific DNA fragment was amplified by PCR from the genomes of rFPV. Western blotting analysis showed that HIV-1 gp120 and IL-2 was expressed not only in chicken embryo fibroblast (CEF) cells infected by rFPV, but also in mammalian cells infected by rFPV. After the recombinant fowlpox virus was inoculated into BALB/c mice, specific CTL activities in the immunized mice were detected in the spleen. The results demonstrated that rFPV had good immunogenicity and could induce BALB/c mice to produce specific cellular immunity. IL-2 played a role of immunoadjuvant and enhanced the cellular immune response. The study provides the basis for the preparation of a Chinese vaccine candidate against HIV-1.
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Affiliation(s)
- Wenzheng Jiang
- School of Life Science, East China Normal University, Shanghai, 200062, PR China
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35
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Falcigno L, Oliva R, D'Auria G, Maletta M, Dettin M, Pasquato A, Di Bello C, Paolillo L. Structural investigation of the HIV-1 envelope glycoprotein gp160 cleavage site 3: role of site-specific mutations. Chembiochem 2005; 5:1653-61. [PMID: 15526330 DOI: 10.1002/cbic.200400181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Proteolytic processing of HIV gp160 to produce gp120 and gp41 is performed by PC enzymes. This process is a prerequisite for the virus infectivity, since both gp120 and gp41 participate in the virus HIV-1 entry mechanism. The structure of the gp120/gp41 junction remains to be elucidated, and the structural features required for molecular recognition between HIV-1 gp160 and proteolytic enzymes have not been clarified. Furin is the best PC candidate for the gp160 proteolytic processing known to date. In previous studies on model peptides, we have shown the relevance of an N-terminal helix for the proper recognition of the gp160 processing site by furin. Here we analyze the effect of point mutations in peptides lacking a regular N-terminal helix. To this end, we present the structure-activity characterization of three peptide analogues of the HIV gp160 processing site that all present mutations in proline at positions P3 and/or P2', while sharing the same N-terminal sequence, containing helix-breaking D-amino acids. Conformational analysis of the peptides was carried out in solution by NMR techniques, and furin's efficiency in cleaving them was measured. Structural findings are presented and discussed in relation to the different exhibited activity.
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Affiliation(s)
- Lucia Falcigno
- Dipartimento di Chimica, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cintia, 80126 Napoli, Italy
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36
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Nie G, Li Y, Wang M, Liu YX, Findlay JK, Salamonsen LA. Inhibiting Uterine PC6 Blocks Embryo Implantation: An Obligatory Role for a Proprotein Convertase in Fertility1. Biol Reprod 2005; 72:1029-36. [PMID: 15601911 DOI: 10.1095/biolreprod.104.036889] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Successful embryo implantation involves complex interactions between the embryo and the uterus and is critical in establishing pregnancy. Proprotein convertase (PC) 6 (PC6) is one of the PC endoproteases regulating protein function through posttranslational activation of precursor proteins, including growth and differentiation factors. Here we show that PC6 protein is induced in the uterine stromal cells specifically at the site of embryo attachment during early pregnancy in mice. In vivo blocking of uterine production of PC6 protein using morpholino antisense oligonucleotides in mice resulted in total inhibition of implantation, revealing a vital role for PC6 in modulating the uterus for embryo implantation. Studies in primates (rhesus monkey and human) showed a dramatic upregulation of endometrial PC6 during the phase of uterine receptivity and at implantation, particularly during a critical uterine cell differentiation process termed decidualization. Thus, the current studies have demonstrated that PC6 is an essential molecule in modulating uterine function to support the establishment of embryo implantation. Interestingly, PC6 is one of the PCs identified to be important in processing the coat protein of HIV; inhibition of PCs has been suggested to be an effective approach to reduce HIV transmission. We therefore propose the novel concept that PC6 could be a potential nonhormonal target in the female reproductive tract for dual protection for women, both in preventing pregnancy and reducing HIV infection.
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Affiliation(s)
- Guiying Nie
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia.
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37
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Nie G, Findlay JK, Salamonsen LA. Identification of novel endometrial targets for contraception. Contraception 2005; 71:272-81. [PMID: 15792646 DOI: 10.1016/j.contraception.2004.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 12/02/2004] [Indexed: 11/28/2022]
Abstract
Successful embryo implantation is a critical step in establishing pregnancy and requires appropriate preparation of the endometrium to provide a transient state of "uterine receptivity." The most essential of the molecular events determining receptivity may therefore provide potential targets for postcoital contraception. Using the mouse as a model, we identified molecules specifically regulated in the endometrium at very early implantation: these were monoclonal nonspecific suppressor factor beta (MNSFbeta), splicing factor SC35, a novel protease of the HtrA family, termed HtrA3, calcium-binding protein (CaBP)-d9k (calbindin d9k) and proprotein convertase 6 (PC6). All of these molecules were also expressed in human endometrium, with the exception of CaBP-d9k, which was represented by the functionally similar CaBP-d28k. Appropriate spatial and temporal expressions of mRNA and protein were demonstrated for all five candidate molecules in mouse and primate (human and rhesus monkey) endometrium during the menstrual cycle and early pregnancy. Functional studies in mice established that blocking production of the CaBPs and PC6 within the endometrium completely prevented implantation and thus provided proof of principle that these molecules are potential contraceptive targets.
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Affiliation(s)
- Guiying Nie
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
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38
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Wickham L, Benjannet S, Marcinkiewicz E, Chretien M, Seidah NG. Beta-amyloid protein converting enzyme 1 and brain-specific type II membrane protein BRI3: binding partners processed by furin. J Neurochem 2005; 92:93-102. [PMID: 15606899 DOI: 10.1111/j.1471-4159.2004.02840.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using a yeast two-hybrid system, we screened a human brain cDNA library for possible interacting proteins with the C-terminal cytosolic tail of the beta-secretase beta-amyloid protein converting enzyme (BACE)1. This identified seven potential candidates, including the brain-specific type II membrane protein BRI3. Co-localization and co-immunoprecipitation experiments confirmed that BACE1 and BRI3 co-localize and interact with each other via the cytosolic tail of BACE1. Furthermore, pulse and pulse-chase analyses revealed that the pro-protein convertases furin, and to a lesser extent PC7 and PC5A, process BRI3 into a C-terminal secreted approximately 4-kDa product. Thus, furin efficiently processes both pro-BACE1 and its novel interacting protein pro-BRI3.
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Affiliation(s)
- Louise Wickham
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
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39
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Müller EJ, Caldelari R, Posthaus H. Role of subtilisin-like convertases in cadherin processing or the conundrum to stall cadherin function by convertase inhibitors in cancer therapy. J Mol Histol 2005; 35:263-75. [PMID: 15339046 DOI: 10.1023/b:hijo.0000032358.51866.a2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cadherins are a family of intercellular adhesion receptors. Produced as inactive precursors, they become functional adhesion molecules after proteolytic cleavage by subtilisin-like pro-protein convertases (PCs). Owing to their activation and assembly into multiprotein adhesion complexes at sites of cell contacts, adhesion-competent cadherins are prerequisite for tissue integrity. In recent years evidence has accumulated that intercellular junctions not only provide mechanical linkage, but in addition are potent modulators of signalling cascades. This infers a biological role to intercellular adhesion complexes that is significantly more complex and powerful. Currently, the broad implications of disturbances in somatic tissue adhesion components are only just beginning to emerge. Prominent examples of adhesion defects include autoimmune diseases, or tumour invasion and metastasis and malignant transformation. This review reports on our current knowledge of cadherin function and their maturation by pro-protein convertases, and puts special emphasis on the consequences of pro-protein convertase inhibition for epithelial tissue homeostasis.
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Affiliation(s)
- E J Müller
- Institute of Animal Pathology, University of Berne, Bern, Switzerland
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40
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Delgado M, Pozo D, Ganea D. The significance of vasoactive intestinal peptide in immunomodulation. Pharmacol Rev 2004; 56:249-90. [PMID: 15169929 DOI: 10.1124/pr.56.2.7] [Citation(s) in RCA: 295] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
First identified by Said and Mutt some 30 years ago, the vasoactive intestinal peptide (VIP) was originally isolated as a vasodilator peptide. Subsequently, its biochemistry was elucidated, and within the 1st decade, their signature features as a neuropeptide became consolidated. It did not take long for these insights to permeate the field of immunology, out of which surprising new attributes for VIP were found in the last years. VIP is rapidly transforming into something more than a mere hormone. In evolving scientifically from a hormone to a novel agent for modifying immune function and possibly a cytokine-like molecule, VIP research has engaged many physiologists, molecular biologists, biochemists, endocrinologists, and pharmacologists and it is a paradigm to explore mutual interactions between neural and neuroendocrine links in health and disease. The aim of this review is firstly to update our knowledge of the cellular and molecular events relevant to VIP function on the immune system and secondly to gather together recent data that support its role as a type 2 cytokine. Recognition of the central functions VIP plays in cellular processes is focusing our attention on this "very important peptide" as exciting new candidates for therapeutic intervention and drug development.
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Affiliation(s)
- Mario Delgado
- Instituto de Parasitologia y Biomedicina "Lopez Neyra," Calle Ventanilla 11, Granada 18001, Spain.
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41
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Keelapang P, Sriburi R, Supasa S, Panyadee N, Songjaeng A, Jairungsri A, Puttikhunt C, Kasinrerk W, Malasit P, Sittisombut N. Alterations of pr-M cleavage and virus export in pr-M junction chimeric dengue viruses. J Virol 2004; 78:2367-81. [PMID: 14963133 PMCID: PMC369205 DOI: 10.1128/jvi.78.5.2367-2381.2004] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2003] [Accepted: 11/07/2003] [Indexed: 12/20/2022] Open
Abstract
During the export of flavivirus particles through the secretory pathway, a viral envelope glycoprotein, prM, is cleaved by the proprotein convertase furin; this cleavage is required for the subsequent rearrangement of receptor-binding E glycoprotein and for virus infectivity. Similar to many furin substrates, prM in vector-borne flaviviruses contains basic residues at positions P1, P2, and P4 proximal to the cleavage site; in addition, a number of charged residues are found at position P3 and between positions P5 and P13 that are conserved for each flavivirus antigenic complex. The influence of additional charged residues on pr-M cleavage and virus replication was investigated by replacing the 13-amino-acid, cleavage-proximal region of a dengue virus (strain 16681) with those of tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV) and by comparing the resultant chimeric viruses generated from RNA-transfected mosquito cells. Among the three chimeric viruses, cleavage of prM was enhanced to a larger extent in JEVpr/16681 than in YFVpr/16681 but was slightly reduced in TBEVpr/16681. Unexpectedly, JEVpr/16681 exhibited decreased focus size, reduced peak titer, and depressed replication in C6/36, PS, and Vero cell lines. The reduction of JEVpr/16681 multiplication correlated with delayed export of infectious virions out of infected cells but not with changes in specific infectivity. Binding of JEVpr/16681 to immobilized heparin and the heparin-inhibitable infection of cells were not altered. Thus, diverse pr-M junction-proximal sequences of flaviviruses differentially influence pr-M cleavage when tested in a dengue virus prM background. More importantly, greatly enhanced prM cleavability adversely affects dengue virus export while exerting a minimal effect on infectivity. Because extensive changes of charged residues at the pr-M junction, as in JEVpr/16681, were not observed among a large number of dengue virus isolates, these results provide a possible mechanism by which the sequence conservation of the pr-M junction of dengue virus is maintained in nature.
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Affiliation(s)
- Poonsook Keelapang
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, USA
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42
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Vincent MJ, Sanchez AJ, Erickson BR, Basak A, Chretien M, Seidah NG, Nichol ST. Crimean-Congo hemorrhagic fever virus glycoprotein proteolytic processing by subtilase SKI-1. J Virol 2003; 77:8640-9. [PMID: 12885882 PMCID: PMC167219 DOI: 10.1128/jvi.77.16.8640-8649.2003] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Accepted: 05/27/2003] [Indexed: 01/17/2023] Open
Abstract
Crimean-Congo hemorrhagic fever (CCHF) virus is a tick-borne member of the genus Nairovirus, family Bunyaviridae. The mature virus glycoproteins, Gn and Gc (previously referred to as G2 and G1), are generated by proteolytic cleavage from precursor proteins. The amino termini of Gn and Gc are immediately preceded by tetrapeptides RRLL and RKPL, respectively, leading to the hypothesis that SKI-1 or related proteases may be involved (A. J. Sanchez, M. J. Vincent, and S. T. Nichol, J. Virol. 76:7263-7275, 2002). In vitro peptide cleavage data show that an RRLL peptide representing the Gn processing site is efficiently cleaved by SKI-1 protease, whereas an RKPL peptide representing the Gc processing site is cleaved at negligible levels. The efficient cleavage of RRLL peptide is consistent with the known recognition sequences of SKI-1, including the sequence determinants involved in the cleavage of the Lassa virus (family Arenaviridae) glycoprotein precursor. These in vitro findings were confirmed by expression of wild-type or mutant CCHF virus glycoproteins in CHO cells engineered to express functional or nonfunctional SKI-1. Gn processing was found to be dependent on functional SKI-1, whereas Gc processing was not. Gn processing occurred in the endoplasmic reticulum-cis Golgi compartments and was dependent on an R at the -4 position within the RRLL recognition motif, consistent with the known cleavage properties of SKI-1. Comparison of SKI-1 cleavage efficiency between peptides representing Lassa virus GP2 and CCHF virus Gn cleavage sites suggests that amino acids flanking the RRLL may modulate the efficiency. The apparent lack of SKI-1 cleavage at the CCHF virus Gc RKPL site indicates that related proteases, other than SKI-1, are likely to be involved in the processing at this site and identical or similar sites utilized in several New World arenaviruses.
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Affiliation(s)
- Martin J Vincent
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, USA
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Bergeron E, Basak A, Decroly E, Seidah NG. Processing of alpha4 integrin by the proprotein convertases: histidine at position P6 regulates cleavage. Biochem J 2003; 373:475-84. [PMID: 12691605 PMCID: PMC1223497 DOI: 10.1042/bj20021630] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2002] [Revised: 03/17/2003] [Accepted: 04/14/2003] [Indexed: 11/17/2022]
Abstract
The proprotein convertases (PCs) participate in the limited proteolysis of integrin alpha4 subunit at the H(592)VISKR(597) downward arrow ST site (where underlined residues indicate positively charged amino acids important for PC-mediated cleavage and downward arrow indicates the cleavage site), since this cleavage is inhibited by the serpin alpha1-PDX (alpha1-antitrypsin Portland). Co-expression of alpha4 with each convertase in LoVo (furin-deficient human colon carcinoma) cells revealed that furin and proprotein convertase 5A (PC5A) are the best pro-alpha4 convertases. In agreement, processing of endogenous pro-alpha4 in human lymphoblastoid CEM-T4 cells was enhanced greatly in stable transfectants overexpressing either enzyme. In many leucocyte cell lines, the expression of furin closely correlated with the endogenous processing efficacy, suggesting that furin is a candidate pro-alpha4 convertase. Mutational analysis showed that replacement of P1 Arg(597) with alanine (R597A) abrogated cleavage, whereas the P6 mutant H592R is even better processed by the endogenous convertases of Chinese-hamster ovary CHO-K1 cells. In vitro kinetic studies using synthetic peptides confirmed the importance of a positively charged residue at P6 and showed that wild-type alpha4 processing is performed best by furin and PC5A at acidic and neutral pHs, respectively. Biosynthetic analysis of pro-alpha4 and its H592R and H592K mutants in the presence or absence of the weak base, NH(4)Cl, revealed that the P6 histidine residue renders its processing by furin sensitive to cellular pH. This suggests that pro-alpha4 cleavage occurs preferentially in acidic compartments. In conclusion, although the accepted furin processing motif is Arg-Xaa-(Lys/Arg)-Arg downward arrow, our data further extend it to include a regulatory histidine residue at P6 in precursors that lack a basic residue at P4.
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Affiliation(s)
- Eric Bergeron
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC, Canada, H2W 1R7
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Taylor NA, Van De Ven WJM, Creemers JWM. Curbing activation: proprotein convertases in homeostasis and pathology. FASEB J 2003; 17:1215-27. [PMID: 12832286 DOI: 10.1096/fj.02-0831rev] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The proprotein convertases (PCs) are a seven-member family of endoproteases that activate proproteins by cleavage at basic motifs. Expression patterns for individual PCs vary widely, and all cells express several members. The list of substrates activated by PCs has grown to include neuropeptides, peptide hormones, growth and differentiation factors, receptors, enzymes, adhesion molecules, blood coagulation factors, plasma proteins, viral coat proteins, and bacterial toxins. It has become clear that the PC family plays a crucial role in a variety of physiological processes and is involved in the pathology of diseases such as cancer, viral infection, and Alzheimer's disease. Recent studies using PC inhibitors have demonstrated their potential as therapeutic targets. Despite the avalanche of in vitro data, the physiological role of individual PCs has remained largely elusive. Recently, however, knockout mouse models have been developed for furin, PC1, PC2, PC4, PC6B, LPC, and PACE4, and human patients with PC1 deficiency have been identified. The phenotypes range from undetectable to early embryonic lethality. The major lesson learned from these studies is that specific PC-substrate pairs do exist, but that there is substantial redundancy for the majority of substrates. To some extent, redundancy may be cell type and even species dependent.
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Affiliation(s)
- Neil A Taylor
- Laboratory of Molecular Oncology, Department for Human Genetics, University of Leuven and Flanders Interuniversity Institute for Biotechnology, Gasthuisberg O/N 6, Herestraat 49, B-3000 Leuven, Belgium
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Kalus I, Schnegelsberg B, Seidah NG, Kleene R, Schachner M. The proprotein convertase PC5A and a metalloprotease are involved in the proteolytic processing of the neural adhesion molecule L1. J Biol Chem 2003; 278:10381-8. [PMID: 12529374 DOI: 10.1074/jbc.m208351200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The transmembrane and multidomain neural adhesion molecule L1 plays important functional roles in the developing and adult nervous system. L1 is proteolytically processed at two distinct sites within the extracellular domain, leading to the generation of different fragments. In this report, we present evidence that the proprotein convertase PC5A is the protease that cleaves L1 in the third fibronectin type III domain, whereas the proprotein convertases furin, PC1, PC2, PACE4, and PC7 are not effective in cleaving L1. Analysis of mutations revealed Arg(845) to be the site of cleavage generating the N-terminal 140-kDa fragment. This fragment was present in the hippocampus, which expresses PC5A, but was not detectable in the cerebellum, which does not express PC5A. The 140-kDa L1 fragment was found to be tightly associated with the full-length 200-kDa L1 molecule. The complex dissociated from the membrane upon cleavage by a protease acting at a more membrane-proximal site of full-length L1. This proteolytic cleavage was inhibited by the metalloprotease inhibitor GM 6001 and enhanced by a calmodulin inhibitor. L1-dependent neurite outgrowth of cerebellar neurons was inhibited by GM 6001, suggesting that proteolytic processing of L1 by a metalloprotease is involved in neurite outgrowth.
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Affiliation(s)
- Ina Kalus
- Zentrum für Molekulare Neurobiologie, University of Hamburg, Martinistrasse 52, Germany
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Abstract
Proprotein convertases (PCs) are known to activate many important molecules and their overexpression plays a significant role in tumor progression. Only little is known about the involvement of PCs in the processing of cadherin adhesion molecules, which are potent tumor suppressors. Here we show in a baculovirus overexpression system that the desmosomal cadherins Dsg1 and Dsg3 are substrates for the PC furin. Accordingly, inhibition of PCs in differentiating mouse keratinocytes by alpha 1-anti-trypsin Portland (alpha 1-PDX) negatively interfered with pro-epithelial (proE)-cadherin processing, but unexpectedly also resulted in a dramatic reduction of E-cadherin, Dsg1 and Dsg3 protein and Dsg1 mRNA. Because loss of intercellular adhesion is a rate-limiting step in the transition from benign to malignant tumors, these results have significant implications for the use of PC inhibitors as possible therapeutic tools.
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Affiliation(s)
- Horst Posthaus
- Institute of Animal Pathology, University of Bern, Laenggass Str. 122, 3012 Bern, Switzerland
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Nie GY, Li Y, Minoura H, Findlay JK, Salamonsen LA. Specific and transient up-regulation of proprotein convertase 6 at the site of embryo implantation and identification of a unique transcript in mouse uterus during early pregnancy. Biol Reprod 2003; 68:439-47. [PMID: 12533406 DOI: 10.1095/biolreprod.102.006676] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The present investigation was conducted to identify and characterize an mRNA that was found by RNA differential display to be uniquely regulated at the sites of embryo implantation in mouse uterus. This mRNA was upregulated at the sites of blastocyst attachment at implantation and was identified as proprotein convertase 6 (PC6). PC6 mRNA level was low in the nonpregnant and early pregnant uterus before embryo implantation commenced (before Day 4.5, vaginal plug = Day 0). During the initiation and progression of blastocyst attachment (around Day 4.5), the mRNA was dramatically upregulated only at the implantation sites. The increased transcription was maintained on Day 5.5; the mRNA level declined slightly on Day 6.5 and then fell sharply to reach the nonpregnant level around Days 8.5-10.5. Thus, the upregulation is transient and coincides with the period of embryo attachment and implantation; it is also very specific to implantation sites. In situ hybridization analysis localized the mRNA expression predominantly in the decidual cells immediately surrounding the implanting embryo at the antimesometrial pole. Additionally, multiple mRNA species resulting from alternative splicing were observed in the uterus, as previously reported in the intestine and brain, and further analysis of these transcripts identified a uterine-specific PC6 mRNA. These data lead us to suggest that PC6 plays an important role in the processes of stromal cell decidualization and embryo implantation.
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Affiliation(s)
- Gui-Ying Nie
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia.
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Nour N, Basak A, Chrétien M, Seidah NG. Structure-function analysis of the prosegment of the proprotein convertase PC5A. J Biol Chem 2003; 278:2886-95. [PMID: 12414802 DOI: 10.1074/jbc.m208009200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To investigate if some residues within the prosegment of PC5A are important for its optimal proteolytic function, various PC5A mutants were cellularly expressed, and their processing activities were compared using pro-vascular endothelial growth factor C (pro-VEGF-C) as a substrate. Although wild type PC5A almost completely processes pro-VEGF-C, a prosegment deletion as well as both P1 mutants of the primary (R116A) and secondary (R84A) autocatalytic cleavage sites are inactive. The in vitro inhibitory potency of various decapeptides mimicking the C-terminal sequence of PC5 prosegment (pPC5) revealed that the native (107)QQVVKKRTKR(116) peptide is a nanomolar inhibitor, whereas its P6 mutant K111H is more selective toward PC5A than Furin. In vitro activity assays using the bacterially expressed pPC5 and its mutants revealed them to be very potent nanomolar inhibitors (IC(50)) and only approximately 6-fold more selective inhibitors of PC5A versus Furin. Expression of the preprosegment of PC5 (ppPC5) and its mutants in Chinese hamster ovary FD11 cells overexpressing pro-VEGF-C with either PC5A or Furin showed them to be as good inhibitors of PC5A as the serpin alpha1-antitrypsin Portland (alpha1-PDX), ppFurin, or ppPACE4 but less potent toward overexpressed Furin. In conclusion, cleavages of the prosegment of PC5A at both Arg(116) and Arg(84) are required for PC5A cellular activity, and ppPC5 is a very potent but modestly selective cellular inhibitor of PC5A.
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Affiliation(s)
- Nadia Nour
- Laboratories of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada
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Bahbouhi B, Chazal N, Seidah NG, Chiva C, Kogan M, Albericio F, Giralt E, Bahraoui E. Effects of L- and D-REKR amino acid-containing peptides on HIV and SIV envelope glycoprotein precursor maturation and HIV and SIV replication. Biochem J 2002; 366:863-72. [PMID: 12071862 PMCID: PMC1222836 DOI: 10.1042/bj20020052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2002] [Revised: 05/23/2002] [Accepted: 06/18/2002] [Indexed: 11/17/2022]
Abstract
The aim of the present study was to evaluate the capacity of synthetic l- and d-peptides encompassing the HIV-1(BRU) gp160 REKR cleavage site to interfere with HIV and simian immuno-deficiency virus (SIV) replication and maturation of the envelope glycoprotein (Env) precursors. To facilitate their penetration into cells, a decanoyl (dec) group was added at the N-terminus. The sequences synthesized included dec5d or dec5l (decREKRV), dec9d or dec9l (decRVVQREKRV) and dec14d or dec14l (TKAKRRVVQREKRV). The peptide dec14d was also prepared with a chloromethane (cmk) group as C-terminus. Because l-peptides exhibit significant cytotoxicity starting at 35 microM, further characterization was conducted mostly with d-peptides, which exhibited no cytotoxicity at concentrations higher than 70 microM. The data show that only dec14d and dec14dcmk could inhibit HIV-1(BRU), HIV-2(ROD) and SIV(mac251) replication and their syncytium-inducing capacities. Whereas peptides dec5d and dec9d were inactive, dec14dcmk was at least twice as active as peptide dec14d. At the molecular level, our data show a direct correlation between anti-viral activity and the ability of the peptides to interfere with maturation of the Env precursors. Furthermore, we show that when tested in vitro the dec14d peptide inhibited PC7 with an inhibition constant K(i)=4.6 microM, whereas the peptide dec14l preferentially inhibited furin with a K(i)=28 microM. The fact that PC7 and furin are the major prohormone convertases reported to be expressed in T4 lymphocytes, the principal cell targets of HIV, suggests that they are involved in the maturation of HIV and SIV Env precursors.
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Affiliation(s)
- Bouchaib Bahbouhi
- Laboratoire d'Immuno-Virologie, EA 30-38 Université Paul Sabatier, UFR/SVT, 118 route de Narbonne 31062 Toulouse, France.
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