Asia-Oceania Mass Spectrometry Conference

12:20 - 12:45: High-sensitive spatial and cell-type proteomics
Ruijun Tian, Ph.D., Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, China

Spatial and cell-type multi-omics has drawn tremendous attentition due to its powerfulness for unbiasedly and systematically discovering biomolecules from biomedical samples with high heterogeneity. Comparing with genomic approaches, current proteomic approaches have been largely lagged behind due to the requirement for processing limited amount of samples and high sensitivity for LC-MS analysis. In the present study, we developed a fully integrated proteomics sample preparation technology SISPROT which could efficiently process nanogram level tissue slice sample for removing the staining dyes, protein digestion and peptide desalting. By systematically optimizing the nanoflow capillary column and timsTOF Pro system, more than 3000 proteins could be confidently identified from as small as 50 µm2 of tissue slice processed by SISPROT. By further combining with AI-based multi-color immunohistochemical (IHC) imaging investigation with single-cell resolution at centimeter scale, we achieved high-sensitive spatial visual proteomic analysis of formalin-fixed and parrffin-embedded (FFPE) tissue slice. Furthermore, by adopting the same SISPROT and timsTOF Pro technologies, we routinely performed high-sensitive cell-type proteomics ranging from 10-1000 cells collected by FACS. By seamlessly combining the spatial and cell-type proteomics, we could now understand the tumor heterogeneity at the proteome level than was previously possible.

12:45 - 13:10: The Role of Protein Glycosylation in Neuropsychiatric Disorders
Boyoung Lee, Ph.D., Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea

Protein glycosylation is a complex posttranslational modification (PTM) that regulates protein function by attaching glycans to proteins. However, its role in brain function has been poorly understood. Our laboratory primarily focuses on investigating the role of glycosylation in neuropsychiatric disorders, such as schizophrenia and depression. In this study, we present our recent findings on glycan profiling in animal models of schizophrenia, specifically using Plcb1 knockout mice (Plcb1 KO) as a genetic mouse model. Plcb1 KO mice were selected for this study due to their high genetic linkage to schizophrenia, as observed in patients, and because these knockout mice exhibit schizophrenia-like phenotypes. Firstly, we divided the brains of Plcb1 KO mice into nine regions to map N-glycans. Our analysis revealed abnormal N-glycosylation in the medial prefrontal cortex (mPFC) of Plcb1 KO mice compared to the control group. Additionally, RNA sequencing results demonstrated significant alterations in several enzymes involved in N-glycan biosynthesis pathways. Furthermore, through glycoproteomics analysis, we identified a candidate target glycoprotein with altered N-glycosylation in the knockout mice. We suggest that the aberrant N-glycosylation in the mPFC is associated with cognitive deficits observed in Plcb1 KO mice, which is a core feature of schizophrenia. Additionally, to visualize the spatial distribution of N-glycans, we utilized TimsTOF Flex (Bruker) for MALDI-MSI (Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging) on brain samples from both wild-type and Plcb1 KO mice. In summary, our data strongly indicate that the abnormal N-glycosylation observed in the mPFC contributes to the cognitive impairment observed in schizophrenia. These findings shed light on the potential role of glycosylation in the pathophysiology of neuropsychiatric disorders, specifically schizophrenia, and open avenues for further research and therapeutic interventions.