Changes in tissue protein n-glycosylation and associated molecular signature occur in the human parkinsonian brain in a region-specific manner

Abstract

Parkinson’s Disease (PD) associated state of neuroinflammation due to the aggregation of aberrant proteins is widely reported. One type of post-translational modification involved in protein stability is glycosylation. Here, we aimed to characterise the human Parkinsonian nigro-striatal N-glycome, and related transcriptome/proteome, and its correlation with endoplasmic reticulum stress and unfolded protein response (UPR), providing a comprehensive characterisation of the PD molecular signature. Significant changes were seen upon PD: 3% increase in sialylation and 5% increase in fucosylation in both regions, and 2% increase in oligomannosylated N-glycans in the substantia nigra. In the latter, a decrease in the mRNA expression of sialidases and an upregulation in the UPR pathway were also seen. To show the correlation between these, we also describe a small in vitro study where changes in specific glycosylation trait enzymes (inhibition of sialyltransferases) led to impairments in cell mitochondrial activity, changes in glyco-profile and upregulation in UPR pathways. This complete characterisation of the human nigro-striatal N-glycome provides an insight into the glycomic profile of PD through a transversal approach while combining the other PD “omics” pieces, which can potentially assist in the development of glyco-focused therapeutics.