Deuterium Oxide Labeling for Global Omics Relative Quantification: Application to Lipidomics

A novel
quantitative mass spectrometric method based on partial
metabolic deuterium oxide (D2O) labeling, named “Deuterium
Oxide Labeling for Global Omics Relative Quantification (DOLGOReQ)”,
was developed for relative quantification of lipids on a global scale.
To assess the precision and robustness of DOLGOReQ, labeled and unlabeled
lipids from HeLa cells were mixed in various ratios based on their
cell numbers. Using in-house software developed for automated high-throughput
data analysis of DOLGOReQ, the number of detectable mass isotopomers
and the degree of deuterium labeling were exploited to filter out
low quality quantification results. Quantification of an equimolar
mixture of HeLa cell lipids exhibited high reproducibility and accuracy
across multiple biological and technical replicates. Two orders of
magnitude of effective dynamic range for reasonable relative quantification
could be established with HeLa cells mixed from 10:1 to 1:10 ratios
between labeled and unlabeled samples. The quantification precision
of DOLGOReQ was also illustrated with lipids commonly detected in
both positive and negative ion modes. Finally, quantification performance
of DOLGOReQ was demonstrated in a biological sample by measuring the
relative change in the lipidome of HeLa cells under normal and hypoxia
conditions.