High-resolution LC-MS/MS analysis of brain N-glycans reveals composition-specific changes in Parkinson's disease

Parkinson's disease (PD) is classically defined by basal ganglia pathology; however, dysfunction of the frontal cortex contributes substantially to cognitive impairment. Despite this, the N-glycomic landscape of this region remains poorly characterized. In this study, we profiled N-glycans in frontal cortex tissue from PD brains and matched controls using an LC-MS-based approach. A total of 117 distinct N-glycan compositions spanning high-mannose, hybrid, and complex classes were identified and quantified. At the glycan class level, no significant differences were observed between PD and control samples. In contrast, composition-specific alterations were detected, with a small subset of N-glycans exhibiting differential abundance. Notably, a multi-fucosylated N-glycan (HexNAc4Hex6Fuc2) was significantly upregulated in PD, whereas a sialofucosylated N-glycan (HexNAc6Hex5Fuc1NeuAc2) was significantly downregulated in PD. Additional glycans showed consistent directional trends at nominal significance. Together, these findings indicate that N-glycosylation changes in the PD frontal cortex are selective and composition-specific, rather than reflecting global remodeling of the glycome. This work provides a foundation for future glycoprotein-specific and functional investigations of PD-associated glycosylation.