The emerging landscape of brain glycosylation: from molecular complexity to therapeutic potential.

Glycosylation functions as a pivotal posttranslational modification in proteins and as a distinct biosynthetic process in lipids. In the brain, it plays essential roles in development, function and homeostasis by modulating protein folding, receptor trafficking and intercellular communication. Although glycans constitute less than 1% of the brain's mass, their impact is disproportionately profound. Recent technological advances have uncovered the essential contributions of both protein- and lipid-bound glycans, including N-glycans, O-glycans and gangliosides, to brain physiology and disease. Here we explore the emerging landscape of brain glycosylation, highlighting its distinct roles in neurodevelopment, synaptic organization and immune regulation. Aberrant glycosylation has been implicated in neurodegenerative diseases (for example, Alzheimer's and Parkinson's), psychiatric disorders (for example, depression and schizophrenia) and neurodevelopmental conditions (for example, autism spectrum disorders, attention deficit hyperactivity disorder and dystroglycanopathies). We summarize recent breakthroughs in glycomics technologies, including glycan enrichment, liquid chromatography-tandem mass spectrometry, MALDI-based imaging mass spectrometry and high-throughput omics, which enable molecular and spatial mapping of brain glycosylation. Artificial-intelligence-driven bioinformatics and multi-omics integration are rapidly opening new avenues for deciphering glycan-mediated regulation in brain health and disease. Together, these developments position brain glycosylation as a transformative frontier in neuroscience, with the potential to yield novel diagnostic biomarkers and therapeutic strategies for complex brain disorders.