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Abstract
INTRODUCTION Glycans are increasingly important in the development of new biopharmaceuticals with optimized efficacy, half-life, and antigenicity. Current expression platforms for recombinant glycoprotein therapeutics typically do not produce homogeneous glycans and frequently display non-human glycans which may cause unwanted side effects. To circumvent these issues, glyco-engineering has been applied to different expression systems including mammalian cells, insect cells, yeast, and plants. AREAS COVERED This review summarizes recent developments in glyco-engineering focusing mainly on in vivo expression systems for recombinant proteins. The highlighted strategies aim at producing glycoproteins with homogeneous N- and O-linked glycans of defined composition. EXPERT OPINION Glyco-engineering of expression platforms is increasingly recognized as an important strategy to improve biopharmaceuticals. A better understanding and control of the factors leading to glycan heterogeneity will allow simplified production of recombinant glycoprotein therapeutics with less variation in terms of glycosylation. Further technological advances will have a major impact on manufacturing processes and may provide a completely new class of glycoprotein therapeutics with customized functions.
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Affiliation(s)
- Martina Dicker
- a 1 University of Natural Resources and Life Sciences , Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria
| | - Richard Strasser
- b 2 University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria +43 1 47654 6705 ; +43 1 47654 6392 ;
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Pabst M, Küster SK, Wahl F, Krismer J, Dittrich PS, Zenobi R. A Microarray-Matrix-assisted Laser Desorption/Ionization-Mass Spectrometry Approach for Site-specific Protein N-glycosylation Analysis, as Demonstrated for Human Serum Immunoglobulin M (IgM). Mol Cell Proteomics 2015; 14:1645-56. [PMID: 25802287 DOI: 10.1074/mcp.o114.046748] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Indexed: 12/31/2022] Open
Abstract
We demonstrate a new approach for the site-specific identification and characterization of protein N-glycosylation. It is based on a nano-liquid chromatography microarray-matrix assisted laser desorption/ionization-MS platform, which employs droplet microfluidics for on-plate nanoliter reactions. A chromatographic separation of a proteolytic digest is deposited at a high frequency on the microarray. In this way, a short separation run is archived into thousands of nanoliter reaction cavities, and chromatographic peaks are spread over multiple array spots. After fractionation, each other spot is treated with PNGaseF to generate two correlated traces within one run, one with treated spots where glycans are enzymatically released from the peptides, and one containing the intact glycopeptides. Mining for distinct glycosites is performed by searching for the predicted deglycosylated peptides in the treated trace. An identified peptide then leads directly to the position of the "intact" glycopeptide clusters, which are located in the adjacent spots. Furthermore, the deglycosylated peptide can be sequenced efficiently in a simple collision-induced dissociation-MS experiment. We applied the microarray approach to a detailed site-specific glycosylation analysis of human serum IgM. By scanning the treated spots with low-resolution matrix assisted laser desorption/ionization-time-of-flight-MS, we observed all five deglycosylated peptides, including the one originating from the secretory chain. A detailed glycopeptide characterization was then accomplished on the adjacent, untreated spots with high mass resolution and high mass accuracy using a matrix assisted laser desorption ionization-Fourier transform-MS. We present the first detailed and comprehensive mass spectrometric analysis on the glycopeptide level for human polyclonal IgM with high mass accuracy. Besides complex type glycans on Asn 395, 332, 171, and on the J chain, we observed oligomannosidic glycans on Asn 563, Asn 402 and minor amounts of oligomannosidic glycans on the glycosite Asn 171. Furthermore, hybrid type glycans were found on Asn 402, Asn 171 and in traces Asn 332.
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Affiliation(s)
- Martin Pabst
- From the ‡Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Simon Karl Küster
- From the ‡Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Fabian Wahl
- §Sigma-Aldrich Chemie GmbH, Industriestrasse 25, 9471 Buchs (SG), Switzerland
| | - Jasmin Krismer
- From the ‡Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Petra S Dittrich
- From the ‡Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Renato Zenobi
- From the ‡Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland;
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53
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Chromikova V, Mader A, Hofbauer S, Göbl C, Madl T, Gach JS, Bauernfried S, Furtmüller PG, Forthal DN, Mach L, Obinger C, Kunert R. Introduction of germline residues improves the stability of anti-HIV mAb 2G12-IgM. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1536-44. [PMID: 25748881 PMCID: PMC4582045 DOI: 10.1016/j.bbapap.2015.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/16/2015] [Accepted: 02/24/2015] [Indexed: 11/02/2022]
Abstract
Immunoglobulins M (IgMs) are gaining increasing attention as biopharmaceuticals since their multivalent mode of binding can give rise to high avidity. Furthermore, IgMs are potent activators of the complement system. However, they are frequently difficult to express recombinantly and can suffer from low conformational stability. Here, the broadly neutralizing anti-HIV-1 antibody 2G12 was class-switched to IgM and then further engineered by introduction of 17 germline residues. The impact of these changes on the structure and conformational stability of the antibody was then assessed using a range of biophysical techniques. We also investigated the effects of the class switch and germline substitutions on the ligand-binding properties of 2G12 and its capacity for HIV-1 neutralization. Our results demonstrate that the introduced germline residues improve the conformational and thermal stability of 2G12-IgM without altering its overall shape and ligand-binding properties. Interestingly, the engineered protein was found to exhibit much lower neutralization potency than its wild-type counterpart, indicating that potent antigen recognition is not solely responsible for IgM-mediated HIV-1 inactivation.
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Affiliation(s)
- Veronika Chromikova
- Department of Biotechnology, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Alexander Mader
- Department of Biotechnology, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Stefan Hofbauer
- Department of Chemistry, Division of Biochemistry, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria; Department for Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Austria
| | - Christoph Göbl
- Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department of Chemistry, Technical University Munich, Garching, Germany; Institute of Structural Biology, Helmholtz Center Munich, Neuherberg, Germany
| | - Tobias Madl
- Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department of Chemistry, Technical University Munich, Garching, Germany; Institute of Structural Biology, Helmholtz Center Munich, Neuherberg, Germany; Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Austria
| | - Johannes S Gach
- Department of Medicine, Division of Infectious Diseases, University of CA, Irvine, USA
| | - Stefan Bauernfried
- Department of Biotechnology, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Paul G Furtmüller
- Department of Chemistry, Division of Biochemistry, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Donald N Forthal
- Department of Medicine, Division of Infectious Diseases, University of CA, Irvine, USA
| | - Lukas Mach
- Department of Applied Genetics and Cell Biology, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Division of Biochemistry, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Renate Kunert
- Department of Biotechnology, Vienna Institute of BioTechnology at BOKU, University of Natural Resources and Life Sciences, Vienna, Austria.
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Ko K. Expression of recombinant vaccines and antibodies in plants. Monoclon Antib Immunodiagn Immunother 2015; 33:192-8. [PMID: 24937251 DOI: 10.1089/mab.2014.0049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plants are able to perform post-translational maturations of therapeutic proteins required for their functional biological activity and suitable in vivo pharmacokinetics. Plants can be a low-cost, large-scale production platform of recombinant biopharmaceutical proteins such as vaccines and antibodies. Plants, however, lack mechanisms of processing authentic human N-glycosylation, which imposes a major limitation in their use as an expression system for therapeutic glycoproducts. Efforts have been made to circumvent plant-specific N-glycosylation, as well as to supplement the plant's endogenous system with human glycosyltransferases for non-immunogenic and humanized N-glycan production. Herein we review studies on the potential of plants to serve as production systems for therapeutic and prophylactic biopharmaceuticals. We have especially focused on recombinant vaccines and antibodies and new expression strategies to overcome the existing problems associated with their production in plants.
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Affiliation(s)
- Kisung Ko
- Department of Medicine, Therapeutic Protein Engineering Lab, College of Medicine, Chung-Ang University , Seoul, Korea
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Loos A, Castilho A. Transient Glyco-Engineering of N. benthamiana Aiming at the Synthesis of Multi-antennary Sialylated Proteins. Methods Mol Biol 2015; 1321:233-48. [PMID: 26082227 DOI: 10.1007/978-1-4939-2760-9_17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recombinantly produced therapeutic proteins bring benefits to patients and production companies alike. However, due to high production costs the potential of this technology cannot be fully tapped and therefor safe, scalable, and economic alternatives to the standard mammalian cell culture-based manufacturing systems are needed. Plant-based expression systems with their current technological advances constitute such an alternative. Many recombinant biopharmaceuticals are glycoproteins and their structural properties and pharmacokinetics are strongly influenced by their glycosylation profile. Differences in glycosylation between plants and mammals can for this reason result in different therapeutic efficacies. In particular, low levels of sialylation may lead to a short serum half-life of therapeutic proteins and nonhuman types of glycosylation can induce degradation and immunogenic responses. Controlling glycosylation of plant-derived therapeutics is therefore fundamental to enhance their efficacy and eliminate possible adverse effects caused by non-authentic glycosylation. Here we describe methods to transiently express high levels of recombinant proteins in Nicotiana benthamiana and simultaneously modulate their glycosylation pattern towards the synthesis of highly sialylated humanlike structures.
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Affiliation(s)
- Andreas Loos
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
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Barb AW. Intramolecular N-glycan/polypeptide interactions observed at multiple N-glycan remodeling steps through [(13)C,(15)N]-N-acetylglucosamine labeling of immunoglobulin G1. Biochemistry 2014; 54:313-22. [PMID: 25551295 PMCID: PMC4302832 DOI: 10.1021/bi501380t] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Asparagine-linked (N) glycosylation
is a common eukaryotic protein
modification that affects protein folding, function, and stability
through intramolecular interactions between N-glycan
and polypeptide residues. Attempts to characterize the structure–activity
relationship of each N-glycan are hindered by inherent
properties of the glycoprotein, including glycan conformational and
compositional heterogeneity. These limitations can be addressed by
using a combination of nuclear magnetic resonance techniques following
enzymatic glycan remodeling to simultaneously generate homogeneous
glycoforms. However, widely applicable methods do not yet exist. To
address this technological gap, immature glycoforms of the immunoglobulin
G1 fragment crystallizable (Fc) were isolated in a homogeneous state
and enzymatically remodeled with [13C,15N]-N-acetylglucosamine (GlcNAc). UDP-[13C,15N]GlcNAc was synthesized enzymatically in a one-pot reaction from
[13C]glucose and [15N-amido]glutamine. Modifying Fc with recombinantly expressed glycosyltransferases
(Gnt1 and Gnt2) and UDP-[13C,15N]GlcNAc resulted
in complete glycoform conversion as judged by mass spectrometry. Two-dimensional
heteronuclear single-quantum coherence spectra of the Gnt1 product,
containing a single [13C,15N]GlcNAc residue
on each N-glycan, showed that the N-glycan is stabilized through interactions with polypeptide residues.
Similar spectra of homogeneous glycoforms, halted at different points
along the N-glycan remodeling pathway, revealed the
presence of an increased level of interaction between the N-glycan and polypeptide at each step, including mannose
trimming, as the N-glycan was converted to a complex-type,
biantennary form. Thus, conformational restriction increases as Fc N-glycan maturation proceeds. Gnt1 and Gnt2 catalyze fundamental
reactions in the synthesis of every glycoprotein with a complex-type N-glycan; thus, the strategies presented herein can be applied
to a broad range of glycoprotein studies.
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Affiliation(s)
- Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
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Castilho A, Windwarder M, Gattinger P, Mach L, Strasser R, Altmann F, Steinkellner H. Proteolytic and N-glycan processing of human α1-antitrypsin expressed in Nicotiana benthamiana. PLANT PHYSIOLOGY 2014; 166:1839-51. [PMID: 25355867 PMCID: PMC4256845 DOI: 10.1104/pp.114.250720] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 10/28/2014] [Indexed: 05/19/2023]
Abstract
Plants are increasingly being used as an expression system for complex recombinant proteins. However, our limited knowledge of the intrinsic factors that act along the secretory pathway, which may compromise product integrity, renders process design difficult in some cases. Here, we pursued the recombinant expression of the human protease inhibitor α1-antitrypsin (A1AT) in Nicotiana benthamiana. This serum protein undergoes intensive posttranslational modifications. Unusually high levels of recombinant A1AT were expressed in leaves (up to 6 mg g(-1) of leaf material) in two forms: full-length A1AT located in the endoplasmic reticulum displaying inhibitory activity, and secreted A1AT processed in the reactive center loop, thus rendering it unable to interact with target proteinases. We found that the terminal protein processing is most likely a consequence of the intrinsic function of A1AT (i.e. its interaction with proteases [most likely serine proteases] along the secretory pathway). Secreted A1AT carried vacuolar-type paucimannosidic N-glycans generated by the activity of hexosaminidases located in the apoplast/plasma membrane. Notwithstanding, an intensive glycoengineering approach led to secreted A1AT carrying sialylated N-glycan structures largely resembling its serum-derived counterpart. In summary, we elucidate unique insights in plant glycosylation processes and show important aspects of postendoplasmic reticulum protein processing in plants.
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Affiliation(s)
- Alexandra Castilho
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Markus Windwarder
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Pia Gattinger
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Lukas Mach
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Richard Strasser
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Friedrich Altmann
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Herta Steinkellner
- Departments of Applied Genetics and Cell Biology (A.C., P.G., L.M., R.S., H.S.) andChemistry (M.W., F.A.), University of Natural Resources and Life Sciences, 1190 Vienna, Austria
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Research Highlights. Nat Biotechnol 2014. [DOI: 10.1038/nbt.2932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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59
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Affiliation(s)
- Andrew Hiatt
- Mapp Biopharmaceutical, Inc., San Diego, CA 92121
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