High resolution imaging and analysis of extracellular vesicles using mass spectral imaging and machine learning.

Journal: Journal of extracellular biology
Published Date:

Abstract

Extracellular vesicles (EVs) are potentially useful biomarkers for disease detection and monitoring. Development of a label-free technique for imaging and distinguishing small volumes of EVs from different cell types and cell states would be of great value. Here, we have designed a method to explore the chemical changes in EVs associated with neuroinflammation using Time-of-Flight Secondary Ion Mass spectrometry (ToF-SIMS) and machine learning (ML). Mass spectral imaging was able to identify and differentiate EVs released by microglia following lipopolysaccharide (LPS) stimulation compared to a control group. This process requires a much smaller sample size (1 µL) than other molecular analysis methods (up to 50 µL). Conspicuously, we saw a reduction in free cysteine thiols (a marker of cellular oxidative stress associated with neuroinflammation) in EVs from microglial cells treated with LPS, consistent with the reduced cellular free thiol levels measured experimentally. This validates the synergistic combination of ToF-SIMS and ML as a sensitive and valuable technique for collecting and analysing molecular data from EVs at high resolution.

Authors

  • Sarah Elizabeth Bamford
    Centre for Materials and Surface Science and Department of Mathematical and Physical Sciences La Trobe University Bundoora Victoria Australia.
  • Natasha Vassileff
    The Department of Biochemistry and Chemistry La Trobe Institute for Molecular Science La Trobe University Bundoora Victoria Australia.
  • Jereme G Spiers
    The Department of Biochemistry and Chemistry La Trobe Institute for Molecular Science La Trobe University Bundoora Victoria Australia.
  • Wil Gardner
    Centre for Materials and Surface Science and Department of Mathematical and Physical Sciences La Trobe University Bundoora Victoria Australia.
  • David A Winkler
    The Department of Biochemistry and Chemistry La Trobe Institute for Molecular Science La Trobe University Bundoora Victoria Australia.
  • Benjamin W Muir
    CSIRO Manufacturing Clayton Victoria Australia.
  • Andrew F Hill
    The Department of Biochemistry and Chemistry La Trobe Institute for Molecular Science La Trobe University Bundoora Victoria Australia.
  • Paul J Pigram
    Centre for Materials and Surface Science and Department of Mathematical and Physical Sciences La Trobe University Bundoora Victoria Australia.

Keywords

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