Simultaneous Multiplexed Imaging of Biomolecules in Transgenic Mouse Brain Tissues Using Mass Spectrometry Imaging: A Multi-omic Approach

The importance of multi-omic-based approaches to better understand diverse pathological mechanisms including neurodegenerative diseases has emerged. Spatial information can be of great help in understanding how biomolecules interact pathologically and in elucidating target biomarkers for developing therapeutics. While various analytical methods have been attempted for imaging-based biomolecule analysis, a multi-omic approach to imaging remains challenging due to the different characteristics of biomolecules. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool due to its sensitivity, chemical specificity, and high spatial resolution in visualizing chemical information in cells and tissues. In this paper, we suggest a new strategy to simultaneously obtain the spatial information of various kinds of biomolecules that includes both labeled and label-free approaches using ToF-SIMS. The enzyme-assisted labeling strategy for the targets of interest enables the sensitive and specific imaging of large molecules such as peptides, proteins, and mRNA, a task that has been, to date, difficult for any MS analysis. Together with the strength of the analytical performance of ToF-SIMS in the label-free tissue imaging of small biomolecules, the proposed strategy allows one to simultaneously obtain integrated information of spatial distribution of metabolites, lipids, peptides, proteins, and mRNA at a high resolution in a single measurement. As part of the suggested strategy, we present a sample preparation method suitable for MS imaging. Because a comprehensive method to examine the spatial distribution of multiple biomolecules in tissues has remained elusive, our strategy can be a useful tool to support the understanding of the interactions of biomolecules in tissues as well as pathological mechanisms.

Automated summary

The importance of multi-omic-based approaches in understanding various pathological mechanisms, including neurodegenerative diseases, is highlighted. Spatial information is crucial for understanding pathological biomolecular interactions and identifying therapeutic target biomarkers. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool for visualizing chemical information in cells and tissues with high sensitivity, chemical specificity, and spatial resolution. This paper proposes a new strategy using ToF-SIMS to simultaneously obtain spatial information on different biomolecules, including labeled and label-free approaches. The strategy enables sensitive and specific imaging of large molecules such as peptides, proteins, and mRNA, and also provides high-resolution label-free tissue imaging of small biomolecules. This comprehensive approach allows for the integrated analysis of metabolites, lipids, peptides, proteins, and mRNA in tissues, providing valuable insights into biomolecular interactions and pathological mechanisms.