glyXalign: High-throughput migration time alignment preprocessing of electrophoretic data retrieved via multiplexed capillary gel electrophoresis with laser-induced fluorescence detection-based glycoprofiling

High-Throughput Glycomic Methods

Glycomics aims to identify the structure and function of the glycome, the complete set of oligosaccharides (glycans), produced in a given cell or organism, as well as to identify genes and other factors that govern glycosylation. This challenging endeavor requires highly robust, sensitive, and potentially automatable analytical technologies for the analysis of hundreds or thousands of glycomes in a timely manner (termed high-throughput glycomics). This review provides a historic overview as well as highlights recent developments and challenges of glycomic profiling by the most prominent high-throughput glycomic approaches, with N-glycosylation analysis as the focal point. It describes the current state-of-the-art regarding levels of characterization and most widely used technologies, selected applications of high-throughput glycomics in deciphering glycosylation process in healthy and disease states, as well as future perspectives.

GlycoStore: A Platform for H/UPLC and Capillary Electrophoresis Glycan Data

GlycoStore ( http://www.glycostore.org ) is an open access chromatographic and electrophoretic retention database of glycans characterized from glycoproteins, glycolipids, and biotherapeutics. It is a continuation of the GlycoBase project (Oxford Glycobiology Institute and National Institute for Bioprocessing Research and Training, Ireland) but addresses many of the technological limitations that impacted the growth of GlycoBase, in particular, improvements to the bioinformatics architecture, enhancing data annotations and coverage, and improving connectivity with external resources. The first release of GlycoStore (October 2017) contains over 850 glycan entries accompanied by 8500+ retention positions including data from: (1) fluorescently labelled released glycans determined using hydrophilic interaction chromatography (HILIC) ultrahigh-performance liquid chromatography (U/HPLC) and reversed phase (RP)-U/HPLC; (2) porous graphitized carbon chromatography (PGC) interfaced with ESI-MS/MS; and (3) capillary electrophoresis with laser induced fluorescence detection (CE-LIF). In this chapter, we outline the objectives of GlycoStore, and describe a selection of step-by-step workflows for navigating and browsing the information available. We also provide a short description of informatics tools available to query the database using Semantic technologies. The information presented in this chapter supplements our documentation knowledge base that describes interface improvements, new features and tools, and content updates ( https://unicarbkb.freshdesk.com/ ).

Analysis of Monoclonal Antibodies by Capillary Electrophoresis: Sample Preparation, Separation, and Detection

Therapeutic monoclonal antibodies (mAbs) are dominating the biopharmaceutical field due to the fact of their high specificity in the treatment of diverse diseases. Nevertheless, mAbs are very complex glycoproteins exhibiting several macro- and microheterogeneities that may affect their safety, quality, and efficacy. This complexity is very challenging for mAbs development, formulation, and quality control. To tackle the quality issue, a combination of multiple analytical approaches is necessary. In this perspective, capillary electrophoresis has gained considerable interest over the last decade due to the fact of its complementary features to chromatographic approaches. This review provides an overview of the strategies of mAbs and derivatives analysis by capillary electrophoresis hyphenated to ultraviolet, fluorescence, and mass spectrometry detection. The main sample preparation approaches used for mAb analytical characterization (i.e., intact, middle-up/down, and bottom-up) are detailed. The different electrophoretic modes used as well as integrated analysis approaches (sample preparation and separation) are critically discussed.

Capillary (Gel) Electrophoresis-Based Methods for Immunoglobulin (G) Glycosylation Analysis

The in-depth characterization of protein glycosylation has become indispensable in many research fields and in the biopharmaceutical industry. Especially knowledge about modulations in immunoglobulin G (IgG) N-glycosylation and their effect on immunity enabled a better understanding of human diseases and the development of new, more effective drugs for their treatment. This chapter provides a deeper insight into capillary (gel) electrophoresis-based (C(G)E) glycan analysis, addressing its impressive performance and possibilities, its great potential regarding real high-throughput for large cohort studies, as well as its challenges and limitations. We focus on the latest developments with respect to miniaturization and mass spectrometry coupling, as well as data analysis and interpretation. The use of exoglycosidase sequencing in combination with current C(G)E technology is discussed, highlighting possible difficulties and pitfalls. The application section describes the detailed characterization of N-glycosylation, utilizing multiplexed CGE with laser-induced fluorescence detection (xCGE-LIF). Besides a comprehensive overview on antibody glycosylation by comparing species-specific IgGs and human immunoglobulins A, D, E, G, and M, the chapter comprises a comparison of therapeutic monoclonal antibodies from different production cell lines, as well as a detailed characterization of Fab and Fc glycosylation. These examples illustrate the full potential of C(G)E, resolving the smallest differences in sugar composition and structure.

Recent advances in glycoinformatic platforms for glycomics and glycoproteomics

Protein glycosylation is the most complex and prevalent post-translation modification in terms of the number of proteins modified and the diversity generated. To understand the functional roles of glycoproteins it is important to gain an insight into the repertoire of oligosaccharides present. The comparison and relative quantitation of glycoforms combined with site-specific identification and occupancy are necessary steps in this direction. Computational platforms have continued to mature assisting researchers with the interpretation of such glycomics and glycoproteomics data sets, but frequently support dedicated workflows and users rely on the manual interpretation of data to gain insights into the glycoproteome. The growth of site-specific knowledge has also led to the implementation of machine-learning algorithms to predict glycosylation which is now being integrated into glycoproteomics pipelines. This short review describes commercial and open-access databases and software with an emphasis on those that are actively maintained and designed to support current analytical workflows.

Capillary Electrophoresis Separations of Glycans

Capillary electrophoresis has emerged as a powerful approach for carbohydrate analyses since 2014. The method provides high resolution capable of separating carbohydrates by charge-to-size ratio. Principle applications are heavily focused on N-glycans, which are highly relevant to biological therapeutics and biomarker research. Advances in techniques used for N-glycan structural identification include migration time indexing and exoglycosidase and lectin profiling, as well as mass spectrometry. Capillary electrophoresis methods have been developed that are capable of separating glycans with the same monosaccharide sequence but different positional isomers, as well as determining whether monosaccharides composing a glycan are alpha or beta linked. Significant applications of capillary electrophoresis to the analyses of N-glycans in biomarker discovery and biological therapeutics are emphasized with a brief discussion included on carbohydrate analyses of glycosaminoglycans and mono-, di-, and oligosaccharides relevant to food and plant products. Innovative, emerging techniques in the field are highlighted and the future direction of the technology is projected based on the significant contributions of capillary electrophoresis to glycoscience from 2014 to the present as discussed in this review.

High-throughput glycosylation analysis of therapeutic immunoglobulin G by capillary gel electrophoresis using a DNA analyzer

The Fc glycosylation of therapeutic antibodies is crucial for their effector functions and their behavior in pharmacokinetics and pharmacodynamics. To monitor the Fc glycosylation in bioprocess development and characterization,high-throughput techniques for glycosylation analysis are needed. Here, we describe the development of a largely automated high-throughput glycosylation profiling method with multiplexing capillary-gel-electrophoresis (CGE) with laser induced fluorescence (LIF) detection using a DNA analyzer. After PNGaseF digestion, the released glycans were labeled with 9-aminopyrene-1,3,6-trisulfonic acid (APTS) in 96-well plates, which was followed by the simultaneous analysis of up to 48 samples. The peak assignment was conducted by HILIC-UPLC-MS/MS of the APTS-labeled glycans combined with peak fractionation and subsequent CGE-LIF analysis of the MS-characterized fractions. Quantitative data evaluation of the various IgG glycans was performed automatically using an in-house developed software solution. The excellent method accuracy and repeatability of the test system was verified by comparison with two UPLC-based methods for glycan analysis. Finally, the practical value of the developed method was demonstrated by analyzing the antibody glycosylation profiles from fermentation broths after small scale protein A purification.

Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis

The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis.

Comparative performance of four methods for high-throughput glycosylation analysis of immunoglobulin G in genetic and epidemiological research

The biological and clinical relevance of glycosylation is becoming increasingly recognized, leading to a growing interest in large-scale clinical and population-based studies. In the past few years, several methods for high-throughput analysis of glycans have been developed, but thorough validation and standardization of these methods is required before significant resources are invested in large-scale studies. In this study, we compared liquid chromatography, capillary gel electrophoresis, and two MS methods for quantitative profiling of N-glycosylation of IgG in the same data set of 1201 individuals. To evaluate the accuracy of the four methods we then performed analysis of association with genetic polymorphisms and age. Chromatographic methods with either fluorescent or MS-detection yielded slightly stronger associations than MS-only and multiplexed capillary gel electrophoresis, but at the expense of lower levels of throughput. Advantages and disadvantages of each method were identified, which should inform the selection of the most appropriate method in future studies.