Decoding the function of the human glycome using chemical glycoprobes and glycosensor arrays

With evolutionary selection, a number of glycotransferases (GTs) and glycosidases (GAs) are expressed in human cells to biosynthesize human glycans. These biopolymers, including N-glycans, O-glycans and glycosaminoglycans, are synthetic products from the synergistic action of hundreds of GTs and GAs, and are thereby highly heterogeneous in nature. This results in ambiguity in the functional study of the human glycome with molecular precision. Recent literature has seen the rapid development of chemical glycoprobes for GTs and GAs in live cells and animals under various physiological and disease-relevant conditions, as well as the construction of glycosensor arrays consisting of fluorescently labelled human glycans to decipher their recognition patterns for biological targets (e.g. pathogens and cancer cells) assisted by dimension-reduction analyses. These studies have advanced basic glycobiological research as well as disease diagnosis and therapy. This tutorial review highlights a selection of examples relevant to this interdisciplinary research area and proposes future directions anticipated to make the functional decoding of the human glycome more effective, thus facilitating precision medicine.