Analytical Chemistry

Proteoform-selective imaging of tissues using mass spectrometry



Unraveling the complexity of biological systems relies on the development of new approaches for spatially resolved proteoform-specific analysis of the proteome. Top-down proteomics is a powerful tool, which has been used for the identification of thousands of proteoforms in biological samples. Herein, we present a first spatially resolved top-down proteomics analysis of biological tissues using nanospray desorption electrospray ionization mass spectrometry imaging (nano-DESI MSI). Nano-DESI generates multiply charged protein ions, which is advantageous for their structural characterization using tandem mass spectrometry (MS/MS). Proof-of-concept experiments demonstrate that the nano-DESI MSI combined with on-tissue top-down proteomics is ideally suited for the proteoform-selective imaging of thin tissue sections. Using rat brain tissue as a model system, we provide the first evidence of the differential proteoform expression in different regions of the brain.


Thumbnail image of Proteoform-selective MSI.pdf

Supplementary material

Thumbnail image of Supporting Information.pdf
Supporting information
This document contains the descriptions of methods and experiments, and supplemental figures.
Thumbnail image of Supporting Table.xlsx
Supporting table
This document contains the proteoforms assignments.
Thumbnail image of On-tissue top-down proteomics results.tdReport
Top-down proteomics report
This document is a report of top-down proteomics report.