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Sauvageau J, Koyuturk I, St Michael F, Brochu D, Goneau MF, Schoenhofen I, Perret S, Star A, Robotham A, Haqqani A, Kelly J, Gilbert M, Durocher Y. Simplifying glycan monitoring of complex antigens such as the SARS-CoV-2 spike to accelerate vaccine development. Commun Chem 2023; 6:189. [PMID: 37684364 PMCID: PMC10491790 DOI: 10.1038/s42004-023-00988-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Glycosylation is a key quality attribute that must be closely monitored for protein therapeutics. Established assays such as HILIC-Fld of released glycans and LC-MS of glycopeptides work well for glycoproteins with a few glycosylation sites but are less amenable for those with multiple glycosylation sites, resulting in complex datasets that are time consuming to generate and difficult to analyze. As part of efforts to improve preparedness for future pandemics, researchers are currently assessing where time can be saved in the vaccine development and production process. In this context, we evaluated if neutral and acidic monosaccharides analysis via HPAEC-PAD could be used as a rapid and robust alternative to LC-MS and HILIC-Fld for monitoring glycosylation between protein production batches. Using glycoengineered spike proteins we show that the HPAEC-PAD monosaccharide assays could quickly and reproducibly detect both major and minor glycosylation differences between batches. Moreover, the monosaccharide results aligned well with those obtained by HILIC-Fld and LC-MS.
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Affiliation(s)
- Janelle Sauvageau
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada.
| | - Izel Koyuturk
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, H3C 3J7, Canada
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
| | - Frank St Michael
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Denis Brochu
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Marie-France Goneau
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Ian Schoenhofen
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Sylvie Perret
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
| | - Alexandra Star
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Anna Robotham
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Arsalan Haqqani
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - John Kelly
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Michel Gilbert
- Human Health Therapeutics Research Centre, National Research Council of Canada, 100 Sussex Dr., Ottawa, ON, K1A 0R6, Canada
| | - Yves Durocher
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, H3C 3J7, Canada
- Human Health Therapeutics Research Centre, National Research Council of Canada, 6100 Avenue Royalmount, Montréal, QC, H4P 2R2, Canada
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2
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Impact of the temperature on the interactions between common variants of the SARS-CoV-2 receptor binding domain and the human ACE2. Sci Rep 2022; 12:11520. [PMID: 35798770 PMCID: PMC9261887 DOI: 10.1038/s41598-022-15215-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/21/2022] [Indexed: 11/28/2022] Open
Abstract
Several key mutations in the Spike protein receptor binding domain (RBD) have been identified to influence its affinity for the human Angiotensin-Converting Enzyme 2 (ACE2). Here, we perform a comparative study of the ACE2 binding to the wild type (Wuhan) RBD and some of its variants: Alpha B.1.1.7, Beta B.1.351, Delta B.1.617.2, Kappa B.1.617.1, B.1.1.7 + L452R and Omicron B.1.1.529. Using a coiled-coil mediated tethering approach of ACE2 in a novel surface plasmon resonance (SPR)-based assay, we measured interactions at different temperatures. Binding experiments at 10 °C enhanced the kinetic dissimilarities between the RBD variants and allowed a proper fit to a Langmuir 1:1 model with high accuracy and reproducibility, thus unraveling subtle differences within RBD mutants and ACE2 glycovariants. Our study emphasizes the importance of SPR-based assay parameters in the acquisition of biologically relevant data and offers a powerful tool to deepen our understanding of the role of the various RBD mutations in ACE2 interaction binding parameters.
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3
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Joubert S, Guimond J, Perret S, Malenfant F, Elahi SM, Marcil A, Parat M, Gilbert M, Lenferink A, Baardsnes J, Durocher Y. Production of afucosylated antibodies in CHO cells by co-expression of an anti-FUT8 intrabody. Biotechnol Bioeng 2022; 119:2206-2220. [PMID: 35509261 DOI: 10.1002/bit.28127] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/17/2022] [Accepted: 04/21/2022] [Indexed: 11/11/2022]
Abstract
Some effector functions prompted by IgG antibodies, such as antibody-dependent cell-mediated cytotoxicity (ADCC), strongly depend on the N-glycans linked to asparagine 297 of the Fc region of the protein. A single alpha-(1,6)-fucosyltransferase (FUT8) is responsible for catalyzing the addition of an α-1,6-linked fucose residue to the first GlcNAc residue of the N-linked glycans. Antibodies missing this core fucose show a significantly enhanced ADCC and increased anti-tumor activity, which could help reduce therapeutic dose requirement, potentially translating into reduced safety concerns and manufacturing costs. Several approaches have been developed to modify glycans and improve the biological functions of antibodies. Here, we demonstrate that expression of a membrane-associated anti-FUT8 intrabody engineered to reside in the endoplasmic reticulum and Golgi apparatus can efficiently reduce FUT8 activity and therefore the core-fucosylation of the Fc N-glycan of an antibody. IgG1-producing CHO cells expressing the intrabody secrete antibodies with reduced core fucosylation as demonstrated by lectin blot analysis and UPLC-HILIC glycan analysis. Cells engineered to inhibit directly and specifically alpha-(1,6)-fucosyltransferase activity allows for the production of g/L levels of IgGs with strongly enhanced ADCC effector function, for which the level of fucosylation can be selected. The quick and efficient method described here should have broad practical applicability for the development of next-generation therapeutic antibodies with enhanced effector functions. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Simon Joubert
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Julie Guimond
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Sylvie Perret
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Félix Malenfant
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Seyyed Mehdy Elahi
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Anne Marcil
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Marie Parat
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Michel Gilbert
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Anne Lenferink
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Jason Baardsnes
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
| | - Yves Durocher
- Human Health Therapeutics Research Center, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada
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4
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Colwill K, Galipeau Y, Stuible M, Gervais C, Arnold C, Rathod B, Abe KT, Wang JH, Pasculescu A, Maltseva M, Rocheleau L, Pelchat M, Fazel‐Zarandi M, Iskilova M, Barrios‐Rodiles M, Bennett L, Yau K, Cholette F, Mesa C, Li AX, Paterson A, Hladunewich MA, Goodwin PJ, Wrana JL, Drews SJ, Mubareka S, McGeer AJ, Kim J, Langlois M, Gingras A, Durocher Y. A scalable serology solution for profiling humoral immune responses to SARS-CoV-2 infection and vaccination. Clin Transl Immunology 2022; 11:e1380. [PMID: 35356067 PMCID: PMC8942165 DOI: 10.1002/cti2.1380] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
Objectives Antibody testing against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been instrumental in detecting previous exposures and analyzing vaccine-elicited immune responses. Here, we describe a scalable solution to detect and quantify SARS-CoV-2 antibodies, discriminate between natural infection- and vaccination-induced responses, and assess antibody-mediated inhibition of the spike-angiotensin converting enzyme 2 (ACE2) interaction. Methods We developed methods and reagents to detect SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA). The main assays focus on the parallel detection of immunoglobulin (Ig)Gs against the spike trimer, its receptor binding domain (RBD) and nucleocapsid (N). We automated a surrogate neutralisation (sn)ELISA that measures inhibition of ACE2-spike or -RBD interactions by antibodies. The assays were calibrated to a World Health Organization reference standard. Results Our single-point IgG-based ELISAs accurately distinguished non-infected and infected individuals. For seroprevalence assessment (in a non-vaccinated cohort), classifying a sample as positive if antibodies were detected for ≥ 2 of the 3 antigens provided the highest specificity. In vaccinated cohorts, increases in anti-spike and -RBD (but not -N) antibodies are observed. We present detailed protocols for serum/plasma or dried blood spots analysis performed manually and on automated platforms. The snELISA can be performed automatically at single points, increasing its scalability. Conclusions Measuring antibodies to three viral antigens and identify neutralising antibodies capable of disrupting spike-ACE2 interactions in high-throughput enables large-scale analyses of humoral immune responses to SARS-CoV-2 infection and vaccination. The reagents are available to enable scaling up of standardised serological assays, permitting inter-laboratory data comparison and aggregation.
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Affiliation(s)
- Karen Colwill
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Yannick Galipeau
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
| | - Matthew Stuible
- Mammalian Cell Expression, Human Health Therapeutics Research CentreNational Research Council CanadaMontréalQCCanada
| | - Christian Gervais
- Mammalian Cell Expression, Human Health Therapeutics Research CentreNational Research Council CanadaMontréalQCCanada
| | - Corey Arnold
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
| | - Bhavisha Rathod
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Present address:
Treadwell TherapeuticsTorontoONCanada
| | - Kento T Abe
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Jenny H Wang
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Adrian Pasculescu
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Mariam Maltseva
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
| | - Lynda Rocheleau
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
- The Centre for Infection, Immunity, and InflammationUniversity of OttawaOttawaONCanada
| | - Mahya Fazel‐Zarandi
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Mariam Iskilova
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Miriam Barrios‐Rodiles
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Linda Bennett
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Kevin Yau
- Division of NephrologyDepartment of MedicineSunnybrook Health Sciences CentreTorontoONCanada
| | - François Cholette
- National Microbiology LaboratoryPublic Health Agency of CanadaWinnipegMBCanada
- Department of Medical Microbiology and Infectious DiseasesUniversity of ManitobaWinnipegMBCanada
| | - Christine Mesa
- National Microbiology LaboratoryPublic Health Agency of CanadaWinnipegMBCanada
| | - Angel X Li
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Microbiology, at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Aimee Paterson
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Microbiology, at Mount Sinai HospitalSinai HealthTorontoONCanada
| | - Michelle A Hladunewich
- Division of NephrologyDepartment of MedicineSunnybrook Health Sciences CentreTorontoONCanada
| | - Pamela J Goodwin
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of MedicineUniversity of TorontoTorontoONCanada
| | - Jeffrey L Wrana
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Steven J Drews
- Microbiology, Donation Policy and StudiesCanadian Blood ServicesEdmontonABCanada
- Division of Diagnostic and Applied MicrobiologyDepartment of Laboratory Medicine and PathologyUniversity of AlbertaEdmontonABCanada
| | - Samira Mubareka
- Division of MicrobiologyDepartment of Laboratory Medicine and Molecular DiagnosticsSunnybrook Health Sciences CentreTorontoONCanada
- Biological SciencesSunnybrook Research InstituteTorontoONCanada
- Division of Infectious DiseasesSunnybrook Health Sciences CentreTorontoONCanada
- Department of Laboratory Medicine and PathologyUniversity of TorontoTorontoONCanada
| | - Allison J McGeer
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Microbiology, at Mount Sinai HospitalSinai HealthTorontoONCanada
- Institute of Health Policy, Management and EvaluationUniversity of TorontoTorontoONCanada
| | - John Kim
- National Microbiology LaboratoryPublic Health Agency of CanadaWinnipegMBCanada
| | - Marc‐André Langlois
- Department of Biochemistry, Microbiology, and ImmunologyUniversity of OttawaOttawaONCanada
- The Centre for Infection, Immunity, and InflammationUniversity of OttawaOttawaONCanada
| | - Anne‐Claude Gingras
- Lunenfeld‐Tanenbaum Research Institute at Mount Sinai HospitalSinai HealthTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Yves Durocher
- Mammalian Cell Expression, Human Health Therapeutics Research CentreNational Research Council CanadaMontréalQCCanada
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5
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Soutto M, Bhat N, Khalafi S, Zhu S, Poveda J, Garcia-Buitrago M, Zaika A, El-Rifai W. NF-kB-dependent activation of STAT3 by H. pylori is suppressed by TFF1. Cancer Cell Int 2021; 21:444. [PMID: 34419066 PMCID: PMC8380333 DOI: 10.1186/s12935-021-02140-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/08/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND H. pylori infection is the main risk factor for gastric cancer. In this study, we investigated H. pylori-mediated activation of STAT3 and NF-κB in gastric cancer, using in vitro and in vivo models. METHODS To investigate the activation of NF-κB and STAT3 by H. pylori strains we used in vitro and in vivo mouse models, western blots, immunofluorescence, ChIP Assay, luciferase and quantitative real-time PCR assays. RESULTS Following infection with H. pylori in vitro, we found an earlier phosphorylation of NF-kB-p65 (S536), followed by STAT3 (Y705). Immunofluorescence, using in vitro and in vivo models, demonstrated nuclear localization of NF-kB and STAT3, following H. pylori infection. NF-kB and STAT3 luciferase reporter assays confirmed earlier activation of NF-kB followed by STAT3. In vitro and in vivo models demonstrated induction of mRNA expression of IL-6 (p < 0.001), VEGF-α (p < 0.05), IL-17 (p < 0.001), and IL-23 (p < 0.001). Using ChIP, we confirmed co-binding of both NF-kB-p65 and STAT3 on the IL6 promoter. The reconstitution of Trefoil Factor 1 (TFF1) suppressed activation of NF-kB with reduction in IL6 levels and STAT3 activity, in response to H. pylori infection. Using pharmacologic (BAY11-7082) and genetic (IκB super repressor (IκBSR)) inhibitors of NF-kB-p65, we confirmed the requirement of NF-kB-p65 for activation of STAT3, as measured by phosphorylation, transcription activity, and nuclear localization of STAT3 in in vitro and in vivo models. CONCLUSION Our findings suggest the presence of an early autocrine NF-kB-dependent activation of STAT3 in response to H. pylori infection. TFF1 acts as an anti-inflammatory guard against H. pylori-mediated activation of pro-inflammatory networks.
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Affiliation(s)
- Mohammed Soutto
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Veterans Affairs, Miami Healthcare System, Miami, FL, 33136-1015, USA
| | - Nadeem Bhat
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Shayan Khalafi
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Shoumin Zhu
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Julio Poveda
- Department of Pathology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | | | - Alexander Zaika
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Veterans Affairs, Miami Healthcare System, Miami, FL, 33136-1015, USA
| | - Wael El-Rifai
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA.
- Department of Veterans Affairs, Miami Healthcare System, Miami, FL, 33136-1015, USA.
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Stuible M, Gervais C, Lord-Dufour S, Perret S, L'Abbé D, Schrag J, St-Laurent G, Durocher Y. Rapid, high-yield production of full-length SARS-CoV-2 spike ectodomain by transient gene expression in CHO cells. J Biotechnol 2021; 326:21-27. [PMID: 33301853 PMCID: PMC7720734 DOI: 10.1016/j.jbiotec.2020.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/29/2020] [Accepted: 12/06/2020] [Indexed: 01/06/2023]
Abstract
Recombinant forms of the spike protein of SARS-CoV-2 and related viruses have proven difficult to produce with good yields in mammalian cells. Given the panoply of potential COVID-19 diagnostic tools and therapeutic candidates that require purified spike protein and its importance for ongoing SARS-CoV-2 research, we have explored new approaches for spike production and purification. Three transient gene expression methods based on PEI-mediated transfection of CHO or HEK293 cells in suspension culture in chemically-defined media were compared for rapid production of full-length SARS-CoV-2 spike ectodomain. A high-cell-density protocol using DXB11-derived CHOBRI/55E1 cells gave substantially better yields than the other methods. Different forms of the spike ectodomain were expressed, including the wild-type SARS-CoV-2 sequence and a mutated form (to favor expression of the full-length spike ectodomain stabilized in pre-fusion conformation), with and without fusion to putative trimerization domains. An efficient two-step affinity purification method was also developed. Ultimately, we have been able to produce highly homogenous preparations of full-length spike, both monomeric and trimeric, with yields of 100-150 mg/L in the harvested medium. The speed and productivity of this method support further development of CHO-based approaches for recombinant spike protein manufacturing.
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Affiliation(s)
- Matthew Stuible
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Christian Gervais
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Simon Lord-Dufour
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Sylvie Perret
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Denis L'Abbé
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Joseph Schrag
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Gilles St-Laurent
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada
| | - Yves Durocher
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada.
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7
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Abe KT, Li Z, Samson R, Samavarchi-Tehrani P, Valcourt EJ, Wood H, Budylowski P, Dupuis AP, Girardin RC, Rathod B, Wang JH, Barrios-Rodiles M, Colwill K, McGeer AJ, Mubareka S, Gommerman JL, Durocher Y, Ostrowski M, McDonough KA, Drebot MA, Drews SJ, Rini JM, Gingras AC. A simple protein-based surrogate neutralization assay for SARS-CoV-2. JCI Insight 2020; 5:142362. [PMID: 32870820 PMCID: PMC7566699 DOI: 10.1172/jci.insight.142362] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/31/2020] [Indexed: 12/22/2022] Open
Abstract
Most of the patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mount a humoral immune response to the virus within a few weeks of infection, but the duration of this response and how it correlates with clinical outcomes has not been completely characterized. Of particular importance is the identification of immune correlates of infection that would support public health decision-making on treatment approaches, vaccination strategies, and convalescent plasma therapy. While ELISA-based assays to detect and quantitate antibodies to SARS-CoV-2 in patient samples have been developed, the detection of neutralizing antibodies typically requires more demanding cell-based viral assays. Here, we present a safe and efficient protein-based assay for the detection of serum and plasma antibodies that block the interaction of the SARS-CoV-2 spike protein receptor binding domain (RBD) with its receptor, angiotensin-converting enzyme 2 (ACE2). The assay serves as a surrogate neutralization assay and is performed on the same platform and in parallel with an ELISA for the detection of antibodies against the RBD, enabling a direct comparison. The results obtained with our assay correlate with those of 2 viral-based assays, a plaque reduction neutralization test (PRNT) that uses live SARS-CoV-2 virus and a spike pseudotyped viral vector-based assay.
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Affiliation(s)
- Kento T. Abe
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Zhijie Li
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Reuben Samson
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Payman Samavarchi-Tehrani
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Emelissa J. Valcourt
- Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory (NML), Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Heidi Wood
- Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory (NML), Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Patrick Budylowski
- Department of Immunology and
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Alan P. Dupuis
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Roxie C. Girardin
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Bhavisha Rathod
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Jenny H. Wang
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Miriam Barrios-Rodiles
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Karen Colwill
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Allison J. McGeer
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
- Department of Microbiology, University Health Network and Sinai Health System, Toronto, Ontario, Canada
- Dalla Lana School of Public Health and
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Samira Mubareka
- Department of Laboratory Medicine and Molecular Diagnostics, Division of Microbiology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Division of Infectious Diseases, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Yves Durocher
- Mammalian Cell Expression, Human Health Therapeutics Research Centre, National Research Council Canada, Montréal, Quebec, Canada
| | - Mario Ostrowski
- Department of Immunology and
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Kathleen A. McDonough
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, New York, USA
| | - Michael A. Drebot
- Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory (NML), Public Health Agency of Canada, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology and Infectious Disease, University of Manitoba, Manitoba, Canada
| | - Steven J. Drews
- Canadian Blood Services, Edmonton, AB & Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - James M. Rini
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
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8
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Naider F, Becker JM. A Paradigm for Peptide Hormone-GPCR Analyses. Molecules 2020; 25:E4272. [PMID: 32961885 PMCID: PMC7570734 DOI: 10.3390/molecules25184272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 01/14/2023] Open
Abstract
Work from our laboratories over the last 35 years that has focused on Ste2p, a G protein-coupled receptor (GPCR), and its tridecapeptide ligand α-factor is reviewed. Our work utilized the yeast Saccharomyces cerevisiae as a model system for understanding peptide-GPCR interactions. It explored the structure and function of synthetic α-factor analogs and biosynthetic receptor domains, as well as designed mutations of Ste2p. The results and conclusions are described using the nuclear magnetic resonance interrogation of synthetic Ste2p transmembrane domains (TMs), the fluorescence interrogation of agonist and antagonist binding, the biochemical crosslinking of peptide analogs to Ste2p, and the phenotypes of receptor mutants. We identified the ligand-binding domain in Ste2p, the functional assemblies of TMs, unexpected and interesting ligand analogs; gained insights into the bound α-factor structure; and unraveled the function and structures of various Ste2p domains, including the N-terminus, TMs, loops connecting the TMs, and the C-terminus. Our studies showed interactions between specific residues of Ste2p in an active state, but not resting state, and the effect of ligand activation on the dimerization of Ste2p. We show that, using a battery of different biochemical and genetic approaches, deep insight can be gained into the structure and conformational dynamics of GPCR-peptide interactions in the absence of a crystal structure.
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Affiliation(s)
- Fred Naider
- Department of Chemistry, College of Staten Island, CUNY, 2800 Victory Blvd, Staten Island, NY 10314, USA
| | - Jeffrey M. Becker
- Department of Microbiology, University of Tennessee, 610 Ken and Blaire Mossman Building, 1311 Cumberland Avenue, Knoxville, TN 37996, USA
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9
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Sanches M, D'Angelo I, Jaramillo M, Baardsnes J, Zwaagstra J, Schrag J, Schoenhofen I, Acchione M, Lawn S, Wickman G, Weisser N, Poon DKY, Ng G, Dixit S. AlbuCORE: an albumin-based molecular scaffold for multivalent biologics design. MAbs 2020; 12:1802188. [PMID: 32816577 PMCID: PMC7531512 DOI: 10.1080/19420862.2020.1802188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
As biologics have become a mainstay in the development of novel therapies, protein engineering tools to expand on their structural advantages, namely specificity, affinity, and valency are of interest. Antibodies have dominated this field as the preferred scaffold for biologics development while there has been limited exploration into the use of albumin with its unique physiological characteristics as a platform for biologics design. There has been a great deal of interest to create bispecific and more complex multivalent molecules to build on the advantages offered by protein-based therapeutics relative to small molecules. Here, we explore the use of human serum albumin (HSA) as a scaffold for the design of multispecific biologics. In particular, we describe a structure-guided approach to the design of split HSA molecules we refer to as AlbuCORE, that effectively and spontaneously forms a native albumin-like molecule, but in a heterodimeric state upon co-expression. We show that the split AlbuCORE designs allow the creation of novel fusion entities with unique alternate geometries. We also show that, apart from these AlbuCORE fusion entities, there is an opportunity to explore their albumin-like small hydrophobic molecule carrying capacity as a drug conjugate in these designs.
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Affiliation(s)
| | - Igor D'Angelo
- One Amgen Center Dr, Amgen Inc ., Thousand Oaks, CA, USA
| | - Maria Jaramillo
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - Jason Baardsnes
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - John Zwaagstra
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - Joe Schrag
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - Ian Schoenhofen
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - Mauro Acchione
- Human Health Therapeutics Portfolio, NRC-CNRC , Montreal, QC, Canada
| | - Sam Lawn
- R&D, Zymeworks Inc , Vancouver, BC, Canada
| | | | | | | | - Gordon Ng
- Search and Evaluation, Abbvie Inc , North Chicago, Illinois, USA
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10
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Padet L, Dieudé M, Karakeussian‐Rimbaud A, Yang B, Turgeon J, Cailhier J, Cardinal H, Hébert M. New insights into immune mechanisms of antiperlecan/LG3 antibody production: Importance of T cells and innate B1 cells. Am J Transplant 2019; 19:699-712. [PMID: 30129231 PMCID: PMC6519043 DOI: 10.1111/ajt.15082] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/25/2018] [Accepted: 07/29/2018] [Indexed: 01/25/2023]
Abstract
Autoantibodies against perlecan/LG3 (anti-LG3) have been associated with increased risks of delayed graft function, acute rejection, and reduced long-term survival. High titers of anti-LG3 antibodies have been found in de novo renal transplants recipients in the absence of allosensitizing or autoimmune conditions. Here, we seek to understand the pathways controlling anti-LG3 production prior to transplantation. Mice immunized with recombinant LG3 produce concomitantly IgM and IgG anti-LG3 antibodies suggesting a memory response. ELISpot confirmed the presence of LG3-specific memory B cells in nonimmunized mice. Purification of B1 and B2 subtypes identified peritoneal B1 cells as the major source of memory B cells reactive to LG3. Although nonimmunized CD4-deficient mice were found to express LG3-specific memory B cells, depletion of CD4+ T cells in wild type mice during immunization significantly decreased anti-LG3 production. These results demonstrate that B cell memory to LG3 is T cell independent but that production of anti-LG3 antibodies requires T cell help. Further supporting an important role for T cells in controlling anti-LG3 levels, we found that human renal transplant recipients show a significant decrease in anti-LG3 titers upon the initiation of CNI-based immunosuppression. Collectively, these results identify T cell targeting interventions as a means of reducing anti-LG3 levels in renal transplant patients.
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Affiliation(s)
- Lauriane Padet
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada,Université de MontréalMontrealQuebecCanada
| | - Mélanie Dieudé
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada
| | - Annie Karakeussian‐Rimbaud
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada
| | - Bing Yang
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada,Université de MontréalMontrealQuebecCanada
| | - Julie Turgeon
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada
| | - Jean‐François Cailhier
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada
| | - Héloïse Cardinal
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada
| | - Marie‐Josée Hébert
- Research CentreCentre Hospitalier de l'Université de Montréal (CRCHUM)MontrealQuebecCanada,Canadian National Transplant Research ProgramEdmontonAlbertaCanada,Université de MontréalMontrealQuebecCanada
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11
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Stuible M, Burlacu A, Perret S, Brochu D, Paul-Roc B, Baardsnes J, Loignon M, Grazzini E, Durocher Y. Optimization of a high-cell-density polyethylenimine transfection method for rapid protein production in CHO-EBNA1 cells. J Biotechnol 2018; 281:39-47. [PMID: 29886030 DOI: 10.1016/j.jbiotec.2018.06.307] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/23/2018] [Accepted: 06/06/2018] [Indexed: 12/12/2022]
Abstract
For pre-clinical evaluation of biotherapeutic candidates, protein production by transient gene expression (TGE) in Chinese Hamster Ovary (CHO) cells offers important advantages, including the capability of rapidly and cost-effectively generating recombinant proteins that are highly similar to those produced in stable CHO clones. We have established a novel CHO clone (CHO-3E7) expressing a form of the Epstein-Barr virus nuclear antigen-1 (EBNA-1) with improved TGE productivity relative to parental CHO cells. Taking advantage of a new transfection-compatible media formulation that permits prolonged, high-density culture, we optimized transfection parameters (cell density, plasmid vector and polyethylenimine concentrations) and post-transfection culture conditions to establish a new, high-performing process for rapid protein production. The growth media is chemically defined, and a single hydrolysate feed is added post-transfection, followed by periodic glucose supplementation. This method gave significantly higher yields than our standard low-cell density, F17-based CHO-3E7 TGE method, averaging several hundred mg/l for a panel of recombinant proteins and antibodies. Purified antibodies produced using the two methods had distinct glycosylation profiles but showed identical target binding kinetics by SPR. Key advantages of this new protein production platform include the cost-effectiveness of the transfection reagent, the commercial availability of the culture media and the ability to perform high-cell-density transfection without media change.
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Affiliation(s)
- Matthew Stuible
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Alina Burlacu
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Sylvie Perret
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Denis Brochu
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Béatrice Paul-Roc
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Jason Baardsnes
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Martin Loignon
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Eric Grazzini
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada
| | - Yves Durocher
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount, Montreal, QC, H4P 2R2, Canada.
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12
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McKenzie EA, Abbott WM. Expression of recombinant proteins in insect and mammalian cells. Methods 2018; 147:40-49. [PMID: 29778647 DOI: 10.1016/j.ymeth.2018.05.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/10/2018] [Accepted: 05/15/2018] [Indexed: 12/12/2022] Open
Abstract
Purified recombinant proteins are key reagents in academic and industrial research. The ability to make these proteins quickly often relies on the availability of higher eukaryotic cell hosts such as insect and mammalian cells where there is a very wide range of post-translational modifications, protein folding and trafficking pathways. This enables the generation of many proteins that cannot be made in microbial hosts. In this article we outline some of the most commonly used methods to express recombinant proteins in insect and mammalian cells.
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Affiliation(s)
- Edward A McKenzie
- Protein Expression Facility, Manchester Institute of Biotechnology, Faculty of Life Sciences, 131 Princess Street, Manchester M1 7DN, UK
| | - W Mark Abbott
- Peak Proteins Ltd, Alderley Park, Cheshire SK10 4TG, UK.
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13
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Shao L, Chen Z, Peng D, Soutto M, Zhu S, Bates A, Zhang S, El-Rifai W. Methylation of the HOXA10 Promoter Directs miR-196b-5p-Dependent Cell Proliferation and Invasion of Gastric Cancer Cells. Mol Cancer Res 2018; 16:696-706. [PMID: 29453320 DOI: 10.1158/1541-7786.mcr-17-0655] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/09/2018] [Accepted: 01/24/2018] [Indexed: 01/05/2023]
Abstract
The cross-talk between epigenetics and miRNA expression plays an important role in human tumorigenesis. Herein, the regulation and role of miR-196b-5p in gastric cancer was investigated. qRT-PCR demonstrated that miR-196b-5p is significantly overexpressed in human gastric cancer tissues (P < 0.01). In addition, it was determined that HOXA10, a homeobox family member and host gene for miR-196b-5p, is overexpressed and positively correlated with miR-196b-5p expression levels (P < 0.001). Quantitative pyrosequencing methylation analysis demonstrated significantly lower levels of DNA methylation at the HOXA10 promoter in gastric cancer, as compared with nonneoplastic gastric mucosa specimens. 5-Aza-2'-deoxycytidine treatment confirmed that demethylation of HOXA10 promoter induces the expression of HOXA10 and miR-196b-5p in gastric cancer cell model systems. Using the Tff1 knockout mouse model of gastric neoplasia, hypomethylation and overexpression of HOXA10 and miR-196b-5p in gastric tumors was observed, as compared with normal gastric mucosa from Tff1 wild-type mice. Mechanistically, reconstitution of TFF1 in human gastric cancer cells led to an increased HOXA10 promoter methylation with reduced expression of HOXA10 and miR-196b-5p. Functionally, miR-196b-5p reconstitution promoted human gastric cancer cell proliferation and invasion in vitro In summary, the current data demonstrate overexpression of miR-196b-5p in gastric cancer and suggest that TFF1 plays an important role in suppressing the expression of miR-196b-5p by mediating DNA methylation of the HOXA10 promoter. Loss of TFF1 expression may promote proliferation and invasion of gastric cancer cells through induction of promoter hypomethylation and expression of the HOXA10/miR-196b-5p axis.Implications: This study indicates that loss of TFF1 promotes the aberrant overexpression of HOXA10 and miR-196b-5p by demethylation of the HOXA10 promoter, which provides a new perspective of TFF1/HOXA10/miR-196b-5p functions in human gastric cancer. Mol Cancer Res; 16(4); 696-706. ©2018 AACR.
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Affiliation(s)
- Linlin Shao
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida
| | - Zheng Chen
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida
| | - Dunfa Peng
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida
| | - Mohammed Soutto
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida
| | - Shoumin Zhu
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida
| | - Andreia Bates
- Department of Surgery, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Shutian Zhang
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Wael El-Rifai
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, Florida. .,Department of Veterans Affairs, Miami VA Healthcare System, Miami, Florida.,Sylvester Comprehensive Cancer Center, University of Miami, Miami, Florida
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14
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Abstract
The presence of α2,6-sialic acids on the Fc N-glycan provides anti-inflammatory properties to the IgGs through a mechanism that remains unclear. Fc-sialylated IgGs are rare in humans as well as in industrial host cell lines such as Chinese hamster ovary (CHO) cells. Facilitated access to well-characterized α2,6-sialylated IgGs would help elucidate the mechanism of this intriguing IgG's effector function. This study presents a method for the efficient Fc glycan α2,6-sialylation of a wild-type and a F243A IgG1 mutant by transient co-expression with the human α2,6-sialyltransferase 1 (ST6) and β1,4-galactosyltransferase 1 (GT) in CHO cells. Overexpression of ST6 alone only had a moderate effect on the glycoprofiles, whereas GT alone greatly enhanced Fc-galactosylation, but not sialylation. Overexpression of both GT and ST6 was necessary to obtain a glycoprofile dominated by α2,6-sialylated glycans in both antibodies. The wild-type was composed of the G2FS(6)1 glycan (38%) with remaining unsialylated glycans, while the mutant glycoprofile was essentially composed of G2FS(6)1 (25%), G2FS(3,6)2 (16%) and G2FS(6,6)2 (37%). The α2,6-linked sialic acids represented over 85% of all sialic acids in both antibodies. We discuss how the limited sialylation level in the wild-type IgG1 expressed alone or with GT results from the glycan interaction with Fc's amino acid residues or from intrinsic galactosyl- and sialyl-transferases substrate specificities.
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Key Words
- B4GALT1
- CHO cells
- ECL, Erythrina Cristagalli lectin
- GT, β1,4-galactosyltransferase 1
- HILIC, hydrophilic interaction liquid chromatography
- IgG1
- LC-ESI-MS, liquid chromatography coupled to electrospray ionization mass spectrometry
- MAL-II, Maackia Amurensis lectin II
- N-glycosylation
- PEI, polyethylenimine
- SIAT1
- SNA, Sambucus Nigra agglutinin
- ST6, α2,6-sialyltransferase 1
- TZM, trastuzumab (Herceptin®)
- cIEF, capillary zone electrophoresis isoelectric focusing
- mAbs, monoclonal antibodies
- sialylation
- transfection
- α2,3SA, α2,3-linked sialic acid
- α2,6SA, α2,6-linked sialic acid
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Affiliation(s)
- Céline Raymond
- a Human Health Therapeutics Portfolio; National Research Council of Canada ; Montreal , Canada
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15
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Alvaro CG, Thorner J. Heterotrimeric G Protein-coupled Receptor Signaling in Yeast Mating Pheromone Response. J Biol Chem 2016; 291:7788-95. [PMID: 26907689 PMCID: PMC4824985 DOI: 10.1074/jbc.r116.714980] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The DNAs encoding the receptors that respond to the peptide mating pheromones of the budding yeast Saccharomyces cerevisiae were isolated in 1985, and were the very first genes for agonist-binding heterotrimeric G protein-coupled receptors (GPCRs) to be cloned in any organism. Now, over 30 years later, this yeast and its receptors continue to provide a pathfinding experimental paradigm for investigating GPCR-initiated signaling and its regulation, as described in this retrospective overview.
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Affiliation(s)
- Christopher G Alvaro
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Jeremy Thorner
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
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16
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Preparation of legionaminic acid analogs of sialo-glycoconjugates by means of mammalian sialyltransferases. Glycoconj J 2015; 32:729-34. [DOI: 10.1007/s10719-015-9624-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/20/2015] [Accepted: 09/22/2015] [Indexed: 12/16/2022]
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17
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Soutto M, Chen Z, Saleh MA, Katsha A, Zhu S, Zaika A, Belkhiri A, El-Rifai W. TFF1 activates p53 through down-regulation of miR-504 in gastric cancer. Oncotarget 2015; 5:5663-73. [PMID: 25015107 PMCID: PMC4170596 DOI: 10.18632/oncotarget.2156] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The expression of TFF1 is frequently down-regulated in human gastric cancer whereas its knockout leads to the development of gastric adenomas and carcinomas in mouse models. The molecular mechanisms underlying the TFF1 tumor suppressor functions remain unclear. In this study, we demonstrate, using colony formation assay and Annexin V staining, that reconstitution of TFF1 expression in gastric cancer cell models suppresses cell growth and promotes cell death. Furthermore, using a tumor xenograft mouse model of gastric cancer, we demonstrated that reconstitution of TFF1 suppresses tumor growth in vivo. The results from PG13-luciferase reporter assay and Western blot analysis indicated that TFF1 promotes the expression and transcription activity of the p53 protein. Further analysis using cycloheximide-based protein assay and quantitative real-time PCR data suggested that TFF1 does not interfere with p53 mRNA levels or protein stability. Alternatively, we found that the reconstitution of TFF1 down-regulates miR-504, a negative regulator of p53. Western blot analysis data demonstrated that miR-504 abrogates TFF1-induced p53 protein expression and activity. In conclusion, the in vitro and in vivo data demonstrate, for the first time, a novel mechanism by which the tumor suppressor functions of TFF1 involve activation of p53 through down-regulation of miR-504.
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Affiliation(s)
- Mohammed Soutto
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA. Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Zheng Chen
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mohamed A Saleh
- Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ahmed Katsha
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Shoumin Zhu
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alexander Zaika
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Abbes Belkhiri
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Wael El-Rifai
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA. Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA. Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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18
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Zuber J, Danial SA, Connelly SM, Naider F, Dumont ME. Identification of destabilizing and stabilizing mutations of Ste2p, a G protein-coupled receptor in Saccharomyces cerevisiae. Biochemistry 2015; 54:1787-806. [PMID: 25647246 DOI: 10.1021/bi501314t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The isolation of mutations affecting the stabilities of transmembrane proteins is useful for enhancing the suitability of proteins for structural characterization and identification of determinants of membrane protein stability. We have pursued a strategy for the identification of stabilized variants of the yeast α-factor receptor Ste2p. Because it was not possible to screen directly for mutations providing thermal stabilization, we first isolated a battery of destabilized temperature-sensitive variants, based on loss of signaling function and decreased levels of binding of the fluorescent ligand, and then screened for intragenic second-site suppressors of these phenotypes. The initial screens recovered singly and multiply substituted mutations conferring temperature sensitivity throughout the predicted transmembrane helices of the receptor. All of the singly substituted variants exhibit decreases in cell-surface expression. We then screened randomly mutagenized libraries of clones expressing temperature-sensitive variants for second-site suppressors that restore elevated levels of binding sites for fluorescent ligand. To determine whether any of these were global suppressors, and thus likely stabilizing mutations, they were combined with different temperature-sensitive mutations. Eight of the suppressors exhibited the ability to reverse the defect in ligand binding of multiple temperature-sensitive mutations. Combining certain suppressors into a single allele resulted in levels of suppression greater than that seen with either suppressor alone. Solubilized receptors containing suppressor mutations in the absence of temperature-sensitive mutations exhibit a reduced tendency to aggregate during immobilization on an affinity matrix. Several of the suppressors also exhibit allele-specific behavior indicative of specific intramolecular interactions in the receptor.
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Affiliation(s)
- Jeffrey Zuber
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry , P.O. Box 712, Rochester, New York 14642, United States
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19
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Cohen LS, Fracchiolla KE, Becker J, Naider F. Invited review GPCR structural characterization: Using fragments as building blocks to determine a complete structure. Biopolymers 2014; 102:223-43. [DOI: 10.1002/bip.22490] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Leah S. Cohen
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
| | - Katrina E. Fracchiolla
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
| | - Jeff Becker
- Department of Microbiology; University of Tennessee; Knoxville TN 37996
| | - Fred Naider
- Department of Chemistry; The College of Staten Island, City University of New York (CUNY); Staten Island NY 10314
- Department of Biochemistry; The Graduate Center; CUNY NY 10016-4309
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20
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Sridharan R, Zuber J, Connelly SM, Mathew E, Dumont ME. Fluorescent approaches for understanding interactions of ligands with G protein coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1838:15-33. [PMID: 24055822 PMCID: PMC3926105 DOI: 10.1016/j.bbamem.2013.09.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 11/18/2022]
Abstract
G protein coupled receptors are responsible for a wide variety of signaling responses in diverse cell types. Despite major advances in the determination of structures of this class of receptors, the underlying mechanisms by which binding of different types of ligands specifically elicits particular signaling responses remain unclear. The use of fluorescence spectroscopy can provide important information about the process of ligand binding and ligand dependent conformational changes in receptors, especially kinetic aspects of these processes that can be difficult to extract from X-ray structures. We present an overview of the extensive array of fluorescent ligands that have been used in studies of G protein coupled receptors and describe spectroscopic approaches for assaying binding and probing the environment of receptor-bound ligands with particular attention to examples involving yeast pheromone receptors. In addition, we discuss the use of fluorescence spectroscopy for detecting and characterizing conformational changes in receptors induced by the binding of ligands. Such studies have provided strong evidence for diversity of receptor conformations elicited by different ligands, consistent with the idea that GPCRs are not simple on and off switches. This diversity of states constitutes an underlying mechanistic basis for biased agonism, the observation that different stimuli can produce different responses from a single receptor. It is likely that continued technical advances will allow fluorescence spectroscopy to play an important role in continued probing of structural transitions in G protein coupled receptors. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.
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Affiliation(s)
- Rajashri Sridharan
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Jeffrey Zuber
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Sara M. Connelly
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Elizabeth Mathew
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Mark E. Dumont
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
- Department of Pediatrics, P.O. Box 777, University of Rochester Medical Center, Rochester, NY 14642
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IGFBP-4 anti-angiogenic and anti-tumorigenic effects are associated with anti-cathepsin B activity. Neoplasia 2013; 15:554-67. [PMID: 23633927 DOI: 10.1593/neo.13212] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 02/12/2013] [Accepted: 02/15/2013] [Indexed: 11/18/2022] Open
Abstract
Insulin-like growth factor-binding protein 4 (IGFBP-4/IBP-4) has potent IGF-independent anti-angiogenic and antitumorigenic effects. In this study, we demonstrated that these activities are located in the IGFBP-4 C-terminal protein fragment (CIBP-4), a region containing a thyroglobulin type 1 (Tg1) domain. Proteins bearing Tg1 domains have been shown to inhibit cathepsins, lysosomal enzymes involved in basement membrane degradation and implicated in tumor invasion and angiogenesis. In our studies, CIBP-4 was shown to internalize and co-localize with lysosomal-like structures in both endothelial cells (ECs) and glioblastoma U87MG cells. CIBP-4 also inhibited both growth factor-induced EC tubulogenesis in Matrigel and the concomitant increases in intracellular cathepsin B (CatB) activity. In vitro assays confirmed CIBP-4 capacity to block recombinant CatB activity. Biodistribution analysis of intravenously injected CIBP-4-Cy5.5 in a glioblastoma tumor xenograft model indicated targeted accumulation of CIBP-4 in tumors. Most importantly, CIBP-4 reduced tumor growth in this animal model by 60%. Pleiotropic anti-angiogenic and anti-tumorigenic activities of CIBP-4 most likely underlie its observed therapeutic potential against glioblastoma.
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22
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Salt ions and related parameters affect PEI-DNA particle size and transfection efficiency in Chinese hamster ovary cells. Cytotechnology 2013; 67:67-74. [PMID: 24166598 DOI: 10.1007/s10616-013-9658-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022] Open
Abstract
Transfection efficiency is directly associated with the expression level and quantity of recombinant protein after the transient transfection of animal cells. The transfection process can be influenced by many still-unknown factors, so it is valuable to study the precise mechanism and explore these factors in gene delivery. Polyethylenimine (PEI) is considered to have high transfection efficiency and endosome-disrupting capacity. Here we aimed to investigate optimal conditions for transfection efficiency by setting different parameters, including salt ion concentration, DNA/PEI ratio, and incubation time. We examined the PEI-DNA particle size using a Malvern particle size analyzer and assessed the transfection efficiency using flow cytometry in Chinese hamster ovary-S cells. Salt ions, higher amounts of PEI tended to improve the aggregation of PEI-DNA particles and the particle size of PEI-DNA complexes and the transfection efficiency were increased. Besides, the particle size was also found to benefit from longer incubation time. However, the transfection efficiency increased to maximum of 68.92 % at an incubation time of 10 min, but decreased significantly thereafter to 23.71 %, when incubating for 120 min (P < 0.05). Besides, PEI-DNA complexes formed in salt-free condition were unstable. Our results suggest DNA and PEI incubated in 300 mM NaCl at a ratio of 1:4 for 10 min could achieve the optimal transfection efficiency. Our results might provide guidance for the optimization of transfection efficiency and the industrial production of recombinant proteins.
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Hacker DL, Kiseljak D, Rajendra Y, Thurnheer S, Baldi L, Wurm FM. Polyethyleneimine-based transient gene expression processes for suspension-adapted HEK-293E and CHO-DG44 cells. Protein Expr Purif 2013; 92:67-76. [PMID: 24021764 PMCID: PMC7129890 DOI: 10.1016/j.pep.2013.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/30/2022]
Abstract
A brief overview of principles of TGE using mammalian cells. Description of TGE processes for HEK293 and CHO cells. Description of orbitally shaken bioreactors for suspension cell cultivation. Description of polyethylenime-based transfection processes.
Transient gene expression (TGE) from mammalian cells is an increasingly important tool for the rapid production of recombinant proteins for research applications in biochemistry, structural biology, and biomedicine. Here we review methods for the transfection of human embryo kidney (HEK-293) and Chinese hamster ovary (CHO) cells in suspension culture using the cationic polymer polyethylenimine (PEI) for gene delivery.
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Affiliation(s)
- David L Hacker
- Protein Expression Core Facility, EPFL, CH-1015 Lausanne, Switzerland; Laboratory of Cellular Biotechnology, EPFL, CH-1015 Lausanne, Switzerland.
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Transient gene expression in serum-free suspension-growing mammalian cells for the production of foot-and-mouth disease virus empty capsids. PLoS One 2013; 8:e72800. [PMID: 23977353 PMCID: PMC3748020 DOI: 10.1371/journal.pone.0072800] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/12/2013] [Indexed: 02/04/2023] Open
Abstract
Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. It produces severe economic losses in the livestock industry. Currently available vaccines are based on inactivated FMD virus (FMDV). The use of empty capsids as a subunit vaccine has been reported to be a promising candidate because it avoids the use of virus in the vaccine production and conserves the conformational epitopes of the virus. In this report, we explored transient gene expression (TGE) in serum-free suspension-growing mammalian cells for the production of FMDV recombinant empty capsids as a subunit vaccine. The recombinant proteins produced, assembled into empty capsids and induced protective immune response against viral challenge in mice. Furthermore, they were recognized by anti-FMDV bovine sera. By using this technology, we were able to achieve expression levels that are compatible with the development of a vaccine. Thus, TGE of mammalian cells is an easy to perform, scalable and cost-effective technology for the production of a recombinant subunit vaccine against FMDV.
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25
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Transient and stable expression of the neurotensin receptor NTS1: a comparison of the baculovirus-insect cell and the T-REx-293 expression systems. PLoS One 2013; 8:e63679. [PMID: 23696845 PMCID: PMC3656039 DOI: 10.1371/journal.pone.0063679] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 04/05/2013] [Indexed: 01/06/2023] Open
Abstract
Nowadays, baculovirus-infected insect cells and tetracycline-inducible mammalian cell lines (T-REx-293) are intensively used for G protein-coupled receptor (GPCR) production for crystallography purposes. Here we constructed a suspension T-REx-293 cell line to stably express an engineered neurotensin receptor 1 (NTS1) mutant and we quantitatively compared this cell line with the transient baculovirus-insect cell system throughout a milligram-scale NTS1 expression and purification process. The two systems were comparable with respect to functional NTS1 expression levels and receptor binding affinity for the agonist [3H] neurotensin. However, NTS1 surface display on T-REx-293 cells determined by radio-ligand binding assays was 2.8 fold higher than that on insect cells. This work demonstrates two approaches for preparing milligram quantities of purified NTS1 suitable for structural studies and provides useful input to users in choosing and optimizing an appropriate expression host for other GPCRs.
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26
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Facile backbone structure determination of human membrane proteins by NMR spectroscopy. Nat Methods 2012; 9:834-9. [PMID: 22609626 DOI: 10.1038/nmeth.2033] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 04/25/2012] [Indexed: 12/31/2022]
Abstract
Although nearly half of today's major pharmaceutical drugs target human integral membrane proteins (hIMPs), only 30 hIMP structures are currently available in the Protein Data Bank, largely owing to inefficiencies in protein production. Here we describe a strategy for the rapid structure determination of hIMPs, using solution NMR spectroscopy with systematically labeled proteins produced via cell-free expression. We report new backbone structures of six hIMPs, solved in only 18 months from 15 initial targets. Application of our protocols to an additional 135 hIMPs with molecular weight <30 kDa yielded 38 hIMPs suitable for structural characterization by solution NMR spectroscopy without additional optimization.
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A framework for mapping, visualisation and automatic model creation of signal-transduction networks. Mol Syst Biol 2012; 8:578. [PMID: 22531118 PMCID: PMC3361003 DOI: 10.1038/msb.2012.12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
An intuitive formalism for reconstructing cellular networks from empirical data is presented, and used to build a comprehensive yeast MAP kinase network. The accompanying rxncon software tool can convert networks to a range of standard graphical formats and mathematical models. ![]()
Network mapping at the granularity of empirical data that largely avoids combinatorial complexity Automatic visualisation and model generation with the rxncon open source software tool Visualisation in a range of formats, including all three SBGN formats, as well as contingency matrix or regulatory graph Comprehensive and completely references map of the yeast MAP kinase network in the rxncon format
Intracellular signalling systems are highly complex. This complexity makes handling, analysis and visualisation of available knowledge a major challenge in current signalling research. Here, we present a novel framework for mapping signal-transduction networks that avoids the combinatorial explosion by breaking down the network in reaction and contingency information. It provides two new visualisation methods and automatic export to mathematical models. We use this framework to compile the presently most comprehensive map of the yeast MAP kinase network. Our method improves previous strategies by combining (I) more concise mapping adapted to empirical data, (II) individual referencing for each piece of information, (III) visualisation without simplifications or added uncertainty, (IV) automatic visualisation in multiple formats, (V) automatic export to mathematical models and (VI) compatibility with established formats. The framework is supported by an open source software tool that facilitates integration of the three levels of network analysis: definition, visualisation and mathematical modelling. The framework is species independent and we expect that it will have wider impact in signalling research on any system.
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Raymond C, Tom R, Perret S, Moussouami P, L’Abbé D, St-Laurent G, Durocher Y. A simplified polyethylenimine-mediated transfection process for large-scale and high-throughput applications. Methods 2011; 55:44-51. [DOI: 10.1016/j.ymeth.2011.04.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/12/2011] [Accepted: 04/15/2011] [Indexed: 12/13/2022] Open
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Umanah GKE, Huang LY, Maccarone JM, Naider F, Becker JM. Changes in conformation at the cytoplasmic ends of the fifth and sixth transmembrane helices of a yeast G protein-coupled receptor in response to ligand binding. Biochemistry 2011; 50:6841-54. [PMID: 21728340 DOI: 10.1021/bi200254h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The third intracellular loop (IL3) of G protein-coupled receptors (GPCRs) is an important contact domain between GPCRs and their G proteins. Previously, the IL3 of Ste2p, a Saccharomyces cerevisiae GPCR, was suggested to undergo a conformational change upon activation as detected by differential protease susceptibility in the presence and absence of ligand. In this study using disulfide cross-linking experiments we show that the Ste2p cytoplasmic ends of helix 5 (TM5) and helix 6 (TM6) that flank the amino and carboxyl sides of IL3 undergo conformational changes upon ligand binding, whereas the center of the IL3 loop does not. Single Cys substitution of residues in the middle of IL3 led to receptors that formed high levels of cross-linked Ste2p, whereas Cys substitution at the interface of IL3 and the contiguous cytoplasmic ends of TM5 and TM6 resulted in minimal disulfide-mediated cross-linked receptor. The alternating pattern of residues involved in cross-linking suggested the presence of a 3(10) helix in the middle of IL3. Agonist (WHWLQLKPGQPNleY) induced Ste2p activation reduced cross-linking mediated by Cys substitutions at the cytoplasmic ends of TM5 and TM6 but not by residues in the middle of IL3. Thus, the cytoplasmic ends of TM5 and TM6 undergo conformational change upon ligand binding. An α-factor antagonist (des-Trp, des-His-α-factor) did not influence disulfide-mediated Ste2p cross-linking, suggesting that the interaction of the N-terminus of α-factor with Ste2p is critical for inducing conformational changes at TM5 and TM6. We propose that the changes in conformation revealed for residues at the ends of TM5 and TM6 are affected by the presence of G protein but not G protein activation. This study provides new information about role of specific residues of a GPCR in signal transduction and how peptide ligand binding activates the receptor.
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Affiliation(s)
- George K E Umanah
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, United States
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30
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Schmidt P, Lindner D, Montag C, Berndt S, Beck-Sickinger AG, Rudolph R, Huster D. Prokaryotic expression, in vitro folding, and molecular pharmacological characterization of the neuropeptide Y receptor type 2. Biotechnol Prog 2010; 25:1732-9. [PMID: 19725122 DOI: 10.1002/btpr.266] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
G protein-coupled receptors (GPCRs) are a class of membrane proteins that represent a major target for pharmacological developments. However, there is still little knowledge about GPCR structure and dynamics since high-level expression and characterization of active GPCRs in vitro is extremely complicated. Here, we describe the recombinant expression and functional folding of the human Y(2) receptor from inclusion bodies of E. coli cultures. Milligram protein quantities were produced using high density fermentation and isolated in a single step purification with a yield of over 20 mg/L culture. Extensive studies were carried out on in vitro refolding and stabilization of the isolated receptor in detergent solution. The specific binding of the ligand, the 36 residue neuropeptide Y (NPY), to the recombinant Y(2) receptors in micellar form was shown by several radioligand affinity assays. In competition experiments, an IC(50) value in low nanomolar range could be determined. Further, a K(D) value of 1.9 nM was determined from a saturation assay, where NPY was titrated to the recombinant Y(2) receptors.
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Affiliation(s)
- Peter Schmidt
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
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31
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Recent advances in the production of proteins in insect and mammalian cells for structural biology. J Struct Biol 2010; 172:55-65. [PMID: 20153433 DOI: 10.1016/j.jsb.2010.02.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 02/04/2010] [Accepted: 02/07/2010] [Indexed: 11/22/2022]
Abstract
The production of proteins in sufficient quantity and of appropriate quality is an essential pre-requisite for structural studies. Escherichia coli remains the dominant expression system in structural biology with nearly 90% of the structures in the Protein Data Bank (PDB) derived from proteins produced in this bacterial host. However, many mammalian and eukaryotic viral proteins require post-translation modification for proper folding and/or are part of large multimeric complexes. Therefore expression in higher eukaryotic cell lines from both invertebrate and vertebrate is required to produce these proteins. Although these systems are generally more time-consuming and expensive to use than bacteria, there have been improvements in technology that have streamlined the processes involved. For example, the use of multi-host vectors, i.e., containing promoters for not only E. coli but also mammalian and baculovirus expression in insect cells, enables target genes to be evaluated in both bacterial and higher eukaryotic hosts from a single vector. Culturing cells in micro-plate format allows screening of large numbers of vectors in parallel and is amenable to automation. The development of large-scale transient expression in mammalian cells offers a way of rapidly producing proteins with relatively high throughput. Strategies for selenomethionine-labelling (important for obtaining phase information in crystallography) and controlling glycosylation (important for reducing the chemical heterogeneity of glycoproteins) have also been reported for higher eukaryotic cell expression systems.
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32
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Purification of transmembrane proteins from Saccharomyces cerevisiae for X-ray crystallography. Protein Expr Purif 2010; 71:207-23. [PMID: 20045057 DOI: 10.1016/j.pep.2009.12.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 12/23/2009] [Accepted: 12/26/2009] [Indexed: 01/15/2023]
Abstract
To enhance the quantity and quality of eukaryotic transmembrane proteins (TMPs) available for structure determination by X-ray crystallography, we have optimized protocols for purification of TMPs expressed in the yeast Saccharomyces cerevisiae. We focused on a set of the highest-expressing endogenous yeast TMPs for which there are established biochemical assays. Genes encoding the target TMPs are transferred via ligation-independent cloning to a series of vectors that allow expression of reading frames fused to C-terminal His10 and ZZ (IgG-binding) domains that are separated from the reading frame by a cleavage site for rhinovirus 3C protease. Several TMP targets expressed from these vectors have been purified via affinity chromatography and gel filtration chromatography at levels and purities sufficient for ongoing crystallization trials. Initial purifications were based on expression of the genes under control of a galactose-inducible promoter, but higher cell densities and improved expression have been obtained through use of the yeast ADH2 promoter. Wide variations have been observed in the behavior of different TMP targets during purification; some can be readily purified, while others do not bind efficiently to affinity matrices, are not efficiently cleaved from the matrices, or remain tightly associated with the matrices even after cleavage of the affinity tags. The size, oligomeric state, and composition of purified protein-detergent complexes purified under different conditions were analyzed using a colorimetric assay of detergent concentrations and by analytical size-exclusion chromatography using static light scattering, refractive index, and UV absorption detection to monitor the elution profiles. Effective procedures were developed for obtaining high concentrations of purified TMPs without excessively concentrating detergents.
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Tole S, Mukovozov IM, Huang YW, Magalhaes MAO, Yan M, Crow MR, Liu GY, Sun CX, Durocher Y, Glogauer M, Robinson LA. The axonal repellent, Slit2, inhibits directional migration of circulating neutrophils. J Leukoc Biol 2009; 86:1403-15. [PMID: 19759280 DOI: 10.1189/jlb.0609391] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In inflammatory diseases, circulating neutrophils are recruited to sites of injury. Attractant signals are provided by many different chemotactic molecules, such that blockade of one may not prevent neutrophil recruitment effectively. The Slit family of secreted proteins and their transmembrane receptor, Robo, repel axonal migration during CNS development. Emerging evidence shows that by inhibiting the activation of Rho-family GTPases, Slit2/Robo also inhibit migration of other cell types toward a variety of chemotactic factors in vitro and in vivo. The role of Slit2 in inflammation, however, has been largely unexplored. We isolated primary neutrophils from human peripheral blood and mouse bone marrow and detected Robo-1 expression. Using video-microscopic live cell tracking, we found that Slit2 selectively impaired directional migration but not random movement of neutrophils toward fMLP. Slit2 also inhibited neutrophil migration toward other chemoattractants, namely C5a and IL-8. Slit2 inhibited neutrophil chemotaxis by preventing chemoattractant-induced actin barbed end formation and cell polarization. Slit2 mediated these effects by suppressing inducible activation of Cdc42 and Rac2 but did not impair activation of other major kinase pathways involved in neutrophil migration. We further tested the effects of Slit2 in vivo using mouse models of peritoneal inflammation induced by sodium periodate, C5a, and MIP-2. In all instances, Slit2 reduced neutrophil recruitment effectively (P<0.01). Collectively, these data demonstrate that Slit2 potently inhibits chemotaxis but not random motion of circulating neutrophils and point to Slit2 as a potential new therapeutic for preventing localized inflammation.
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Affiliation(s)
- Soumitra Tole
- The Hospital for Sick Children Research Institute, Toronto, Canada
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Shi C, Kendall SC, Grote E, Kaminskyj S, Loewen MC. N-terminal residues of the yeast pheromone receptor, Ste2p, mediate mating events independently of G1-arrest signaling. J Cell Biochem 2009; 107:630-8. [DOI: 10.1002/jcb.22129] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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Nallet S, Amacker M, Westerfeld N, Baldi L, König I, Hacker DL, Zaborosch C, Zurbriggen R, Wurm FM. Respiratory syncytial virus subunit vaccine based on a recombinant fusion protein expressed transiently in mammalian cells. Vaccine 2009; 27:6415-9. [PMID: 19559121 DOI: 10.1016/j.vaccine.2009.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although respiratory syncytial virus (RSV) causes severe lower respiratory tract infection in infants and adults at risk, no RSV vaccine is currently available. In this report, efforts toward the generation of an RSV subunit vaccine using recombinant RSV fusion protein (rRSV-F) are described. The recombinant protein was produced by transient gene expression (TGE) in suspension-adapted human embryonic kidney cells (HEK-293E) in 4 L orbitally shaken bioreactors. It was then purified and formulated in immunostimulating reconstituted influenza virosomes (IRIVs). The candidate vaccine induced anti-RSV-F neutralizing antibodies in mice, and challenge studies in cotton rats are ongoing. If successful in preclinical and clinical trials, this will be the first recombinant subunit vaccine produced by large-scale TGE in mammalian cells.
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Affiliation(s)
- Sophie Nallet
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Bioengineering, Laboratory of Cellular Biotechnology, CH-1015 Lausanne, Switzerland
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36
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In vitro characterization of ligand-induced oligomerization of the S. cerevisiae G-protein coupled receptor, Ste2p. Biochim Biophys Acta Gen Subj 2008; 1790:1-7. [PMID: 18996443 DOI: 10.1016/j.bbagen.2008.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Revised: 10/10/2008] [Accepted: 10/10/2008] [Indexed: 01/17/2023]
Abstract
BACKGROUND The S. cerevisiae alpha-factor receptor, Ste2p, is a G-protein coupled receptor that plays key roles in yeast signaling and mating. Oligomerization of Ste2p has previously been shown to be important for intracellular trafficking, receptor processing and endocytosis. However the role of ligand in receptor oligomerization remains enigmatic. METHODS Using functional recombinant forms of purified Ste2p, atomic force microscopy, dynamic light scattering and chemical crosslinking are applied to investigate the role of ligand in Ste2p oligomerization. RESULTS Atomic force microscopy images indicate a molecular height for recombinant Ste2p in the presence of alpha-factor nearly double that of Ste2p alone. This observation is supported by complementary dynamic light scattering measurements which indicate a ligand-induced increase in the polydispersity of the Ste2p hydrodynamic radius. Finally, chemical cross-linking of HEK293 plasma membranes presenting recombinant Ste2p indicates alpha-factor induced stabilization of the dimeric form and higher order oligomeric forms of the receptor upon SDS-PAGE analysis. CONCLUSIONS alpha-factor induces oligomerization of Ste2p in vitro and in membrane. GENERAL SIGNIFICANCE These results provide additional evidence of a possible role for ligand in mediation of Ste2p oligomerization in vivo.
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Paris S, Burlacu A, Durocher Y. Opposing Roles of Syndecan-1 and Syndecan-2 in Polyethyleneimine-mediated Gene Delivery. J Biol Chem 2008; 283:7697-704. [DOI: 10.1074/jbc.m705424200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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38
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Lee BK, Jung KS, Son C, Kim H, VerBerkmoes NC, Arshava B, Naider F, Becker JM. Affinity purification and characterization of a G-protein coupled receptor, Saccharomyces cerevisiae Ste2p. Protein Expr Purif 2007; 56:62-71. [PMID: 17646109 PMCID: PMC2065862 DOI: 10.1016/j.pep.2007.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 06/01/2007] [Accepted: 06/10/2007] [Indexed: 11/28/2022]
Abstract
We present an example of expression and purification of a biologically active G-protein coupled receptor (GPCR) from yeast. An expression vector was constructed to encode the Saccharomyces cerevisiae GPCR alpha-factor receptor (Ste2p, the STE2 gene product) containing a 9-amino acid sequence of rhodopsin that served as an epitope/affinity tag. In the construct, two glycosylation sites and two cysteine residues were removed to aid future structural and functional studies. The receptor was expressed in yeast cells and was detected as a single band in a western blot indicating the absence of glycosylation. Ligand binding and signaling assays of the epitope-tagged, mutated receptor showed it maintained the full wild-type biological activity. For extraction of Ste2p, yeast membranes were solubilized with 0.5% n-dodecyl maltoside (DM). Approximately 120 microg of purified alpha-factor receptor was obtained per liter of culture by single-step affinity chromatography using a monoclonal antibody to the rhodopsin epitope. The binding affinity (K(d)) of the purified alpha-factor receptor in DM micelles was 28 nM as compared to K(d)=12.7 nM for Ste2p in cell membranes, and approximately 40% of the purified receptor was correctly folded as judged by ligand saturation binding. About 50% of the receptor sequence was retrieved from MALDI-TOF and nanospray mass spectrometry after CNBr digestion of the purified receptor. The methods described will enable structural studies of the alpha-factor receptor and may provide an efficient technique to purify other GPCRs that have been functionally expressed in yeast.
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Affiliation(s)
- Byung-Kwon Lee
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996 USA
| | - Kyung-Sik Jung
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996 USA
| | - Cagdas Son
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996 USA
| | - Heejung Kim
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996 USA
| | | | - Boris Arshava
- Department of Chemistry, College of Staten Island, CUNY, Staten Island, NY 10301 USA
| | - Fred Naider
- Department of Chemistry, College of Staten Island, CUNY, Staten Island, NY 10301 USA
- The Leonard and Esther Term Professor at the College of Staten Island
| | - Jeffrey M. Becker
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996 USA
- *Address reprint requests to: Jeffrey M. Becker, Tel: 865-974-3006, Fax: 865-974-4007, E-mail address:
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Abstract
Coronins are conserved F-actin binding proteins that have been implicated in a variety of processes including fibroblast migration, phagocytosis, and chemotaxis. Recent data from our lab indicate that coronin 1B coordinates Arp2/3-dependent actin filament nucleation and cofilin-mediated filament turnover at the leading edge of migrating fibroblasts. Analysis of coronin function has been hampered by the lack of a clear understanding of how coronin interacts with F-actin. Here, we identify a surface-exposed conserved arginine residue at position 30 (R30), which is crucial for coronin 1B binding to F-actin both in vitro and in vivo. Using actin co-sedimentation, we demonstrate that coronin 1B binds with high affinity to ATP/ADP-P(i)-F-actin (170 nM) and with 47-fold lower affinity to ADP-F-actin (8 microM). In contrast to a previous study, we find no evidence for enhanced cofilin binding to F-actin in the presence of either coronin 1B or coronin 1A. Instead, we find that coronin 1B protects actin filaments from cofilin-induced depolymerization. Consistent with an important role for interactions between coronin 1B and F-actin in vivo, an R30D coronin mutant that does not bind F-actin localizes inefficiently to the leading edge. Furthermore, our analysis indicates that F-actin binding is absolutely required for coronin 1B to exert its effects on whole-cell motility and lamellipodial dynamics.
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Affiliation(s)
- Liang Cai
- Lineberger Comprehensive Cancer Center, Department of Cell & Developmental Biology, University of North Carolina at Chapel Hill, North Carolina 27599-7295, USA
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40
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Shi C, Kaminskyj S, Caldwell S, Loewen MC. A role for a complex between activated G protein-coupled receptors in yeast cellular mating. Proc Natl Acad Sci U S A 2007; 104:5395-400. [PMID: 17369365 PMCID: PMC1838501 DOI: 10.1073/pnas.0608219104] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cell-cell fusion is a fundamental process that facilitates a wide variety of biological events in organisms ranging from yeast to humans. However, relatively little is actually understood with respect to fusion mechanisms. In the model organism Saccharomyces cerevisiae, mating of opposite-type cells is triggered by pheromone activation of the G protein-coupled receptors, alpha-factor receptor (Ste2p) and a-factor receptor (Ste3p), leading to mitogen-activated protein kinase signaling, growth arrest, and cellular fusion events. Herein we now provide evidence of a role for these receptors in the later cell fusion stage of mating. In vitro assays demonstrated the ability of the receptors to promote mixing of proteoliposomes containing phosphatidylserine, potentially based on a pheromone-dependent interaction between Ste2p and Ste3p that was confirmed by tandem affinity purification and cellular pull-down assays. The cellular mating activity of Ste2p was subsequently probed in vivo. Notably, a receptor-null yeast strain expressing N-terminally truncated Ste2p yielded a phenotype demonstrating wild-type signaling but arrested mating. The arrested prezygotes showed evidence of some cell wall erosion but no membrane juxtaposition at the fusion site. Further, in vitro analyses correlated this mutation with loss of the interaction between Ste2p and Ste3p and inhibition of related lipid mixing. Overall, these results support a role for a complex between activated yeast pheromone receptors in later cell fusion stages of mating, possibly mediating events at the level of cell wall digestion and membrane juxtaposition before membrane fusion.
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Affiliation(s)
- Chunhua Shi
- *Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, Canada S7N 0W9
| | - Susan Kaminskyj
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Sarah Caldwell
- Department of Veterinary Biomedical Science, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
| | - Michèle C. Loewen
- *Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, Canada S7N 0W9
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E2; and
- To whom correspondence should be addressed. E-mail:
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Pham PL, Kamen A, Durocher Y. Large-scale transfection of mammalian cells for the fast production of recombinant protein. Mol Biotechnol 2007; 34:225-37. [PMID: 17172668 DOI: 10.1385/mb:34:2:225] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Recombinant proteins (r-proteins) are increasingly important in fundamental research and for clinical applications. As many of these r-proteins are of human or animal origin, cultivated mammalian cells are the host of choice to ensure their functional folding and proper posttranslational modifications. Large-scale transfection of human embryonic kidney 293 or Chinese hamster ovary cells is now an established technology that can be used in the production of hundreds of milligram to gram quantities of a r-protein in less than 1 mo from cloning of its cDNA. This chapter aims to provide an overview of large-scale transfection technology with a particular emphasis on calcium phosphate and polyethylenimine-mediated gene transfer.
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Affiliation(s)
- Phuong Lan Pham
- Laboratoire de Biotechnologie Vétérinaire et Alimentaire, Faculté de Médecine Vétérinaire, Université de Montréal, CP5000, Sainte-Hyacinthe (Québec) J2S 7C6, Canada
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Baldi L, Hacker DL, Adam M, Wurm FM. Recombinant protein production by large-scale transient gene expression in mammalian cells: state of the art and future perspectives. Biotechnol Lett 2007; 29:677-84. [PMID: 17235486 DOI: 10.1007/s10529-006-9297-y] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 12/19/2006] [Accepted: 12/21/2006] [Indexed: 11/29/2022]
Abstract
The expansion of the biologics pipeline depends on the identification of candidate proteins for clinical trials. Speed is one of the critical issues, and the rapid production of high quality, research-grade material for preclinical studies by transient gene expression (TGE) is addressing this factor in an impressive way: following DNA transfection, the production phase for TGE is usually 2-10 days. Recombinant proteins (r-proteins) produced by TGE can therefore enter the drug development and screening process in a very short time--weeks. With "classical" approaches to protein expression from mammalian cells, it takes months to establish a productive host cell line. This article summarizes efforts in industry and academia to use TGE to produce tens to hundreds of milligrams of r-proteins for either fundamental research or preclinical studies.
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Affiliation(s)
- Lucia Baldi
- Laboratory of Cellular Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Station 6, 1015, Lausanne, Switzerland.
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Current awareness on yeast. Yeast 2006. [DOI: 10.1002/yea.1316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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