We are delighted to present you this year´s keynote speakers, all world-class scientists who have accepted our invitation to present their groundbreaking work in glycoscience at Glycobasque 9.

“Learning molecular recognition in glycobiology via DNA-encoding, machine learning and chirality inversion“
University of Alberta (Canada)
Abstract
Glycans densely coat the surface of all cells in all kingdoms of life. DNA technologies such as single cell sequencing revolutionized investigation of all events associated with the Central Dogma. As the structure of glycans is not encoded by DNA, it is not possible to study glycans using DNA technology. Liquid Glycan Arrays (LiGA) overcome this fundamental barrier by introducing a 1:1 correspondence between DNA sequence and glycan structure and its multivalent presentation on a soluble, monodisperse, nanoscale carrier. LiGA measures interactions of glycans with receptors expressed on the surface of any cell types in vitro and in vivo, inside live animals. We build on this capacity to develop foundational machine learning (ML) models that can extrapolate the strength of glycan:protein interactions for any glycans or proteins. Chirality is critical in glycan:protein recognition. Proteins that recognize glycans bind only to a small subset of plausible stereoisomers. Prediction of stereoisomer-dependent binding is challenging for contemporary foundational ML models. Data for chirality inversion is scarce; furthermore, public data for ML training is dominated by achiral ligands. As a result, many models are not sensitive to minute changes in stereochemistry. LiGA made it possible to collect thousands of high-quality measurements for stereoisomers of core monosaccharides across hundreds of interaction partners such as purified lectins, diverse mammalian cell types, organs inside live mice, and live bacteria. We found that binding of extant proteins to natural glycans of inverted chirality is widespread and can be inhibited by soluble glycans. Human and mouse immune cells show minor binding towards enantiomers of natural glycans. IgMs isolated from human serum showed donor-specific recognition of L-glycans. In retrospect, recognition of L-glycans by extant proteins is not surprising due to the wide prevalence of L-glycans in the glycocalyx of many present-day microorganisms. Recognition of stereoisomers of present-day glycans by extant glycan-binding proteins expands fundamental understanding of processes such as colonization, immune response, and self-versus-nonself discrimination. This evidence-based analysis of molecular recognition makes an important contribution to the recently emerged risk assessment associated with the synthesis of enantiomeric life forms.

“Decoding Glycan Regulation and Display in Human Cells and Tissues”
Leiden University Medical Center (Netherlands)
Abstract
Cell surface glycans play crucial roles in establishing cell communication, adhesion, and migration. Specifically at the cancer cell surface, glycosylation is altered compared to healthy cells, displaying cancer-specific glycoforms. These cancer glycans affect tumor behavior, and can be targeted for treatment. Yet, resolving the precise structures, spatial organization, and regulatory mechanisms of glycoconjugates remains a major analytical challenge.To address this, we developed a suite of versatile mass spectrometry (MS)-based platforms enabling cell type-, cell surface-, and protein‑specific characterization of human glycosylation. Our in-depth LC-MS-based strategies allow deep structural elucidation of the different glycan classes and combining these methods with an array of glycoengineered human cell lines provides insights into glycan structures and their regulation in a cellular context. Complementing this, MS imaging provides spatial maps of N‑glycans within tissues and enables multi‑omic integration with metabolomics and lipidomics to reveal the metabolic context of glycan regulation. Finally, to specifically analyze the N-glycoprotein forms expressed at the cell surface, we combined LC-MS-based glycoproteomics with highly specific cell surface protein labeling and enrichment to study how specific proteins change their glycoforms under defined biological conditions.In summary, we present analytical tools required to study cellular glycosylation in health and disease as well as to track genetic or metabolic manipulation of the glycosylation machinery. Understanding these processes and identifying disease-specific glycoconjugates have important implications for their future use as therapeutic targets.

“Are there sugars in bacteria? What can we do with them”
Indian Institute of Technology Bombay (India)
Abstract
Bacterial glycans are often comprised of rare D and L deoxy amino sugars, which are not present on the human cell surface. This peculiar structural difference allows discrimination between the pathogen and the host cell and offers avenues for target-specific drug discovery and carbohydrate-based vaccine development. However, such complex glycans cannot be isolated with sufficient purity in acceptable amounts, and therefore chemical synthesis is a crucial step toward the development of these products. We recently established short and convenient methodologies for the synthesis of orthogonally protected bacterial D and L-deoxy amino hexopyranoside and glycosamine building blocks starting from easily available D-mannose and L-rhamnose. The one-pot protocols rely on highly regioselective nucleophilic displacements of triflates. These procedures have been applied to the synthesis of highly immunogenic conjugation-ready bacterial glycans as well as zwitterionic oligosaccharides. The azide containing sugars also enabled metabolic oligosaccharide engineering studies that led to discovery of selective inhibitors of glycan biosynthesis. In this talk I will present our recent results on the total synthesis of highly complex and densely functionalized bacterial glycans and the application of rare sugars in selective detection and disarming of pathogens. The synthetic oligosaccharides provide valuable epitopes for immunological studies aimed at vaccine development

“Targeting Tumor Glycosylation to Break Immune Suppression”
University of Basel (Switzerland)
Abstract
Cancer immunotherapy has markedly improved patient outcomes, with immune checkpoint inhibitors inducing durable remissions even in some patients with advanced malignancies. However, the majority of patients derive limited or no benefit from current immunotherapeutic strategies. Targeting cancer-associated glycans represents a promising approach to overcome resistance. This presentation will discuss the development of glycan-targeting antibodies for chimeric antigen receptor (CAR) T cells and bispecific antibodies, as well as strategies to glyco-engineer the tumor microenvironment to enhance antitumor immunity. Preclinical studies demonstrate that enzymatic or small-molecule modulation of tumor-associated glycans can significantly potentiate immunotherapy. Early-phase clinical trials evaluating these glycan-targeted approaches are now underway.

“Glycan Microarrays for Decoding Glycan-Mediated Microbe-Host interactions“
Imperial College London (UK)
Abstract
Glycans mediate a vast network of molecular recognition events that regulate essential biological processes across all living organisms. As prominent components of the host cell surface, they mediate cell adhesion and signalling, maintain barrier function, and serve as attachment sites for microbes, playing critical roles in colonisation and infection. While the glycome defines the full repertoire of glycan structures expressed by a cell, tissue, or organism at a given physiological state, understanding their biological function requires mapping the ‘Glycointeractome’, the complete network of glycan-driven interactions. Glycan microarray technologies, first introduced in 2002 by Professor Ten Feizi FRS and colleagues at Imperial College London, have become indispensable high-throughput platforms used worldwide to interrogate glycan-protein interactions, enabling functional insights at unprecedented scale. In this talk, I will present the unique and expanding glycan libraries, microarray strategies, and data resources established within the ICL Carbohydrate Microarray Facility, and highlight recent discoveries from interdisciplinary collaborations that have advanced our understanding of glycan interactions at immune and host-microbe interfaces. I will also discuss the challenges and translational opportunities of glycan microarrays, and the need for multidisciplinary integration of interaction analyses, systems biology, and data science to achieve comprehensive, mechanistic, and predictive decoding of the glycointeractome.