posted on 2024-01-11, 15:15authored byTingyuan Yang, Shuli Tang, Jiaxin Feng, Xin Yan
Changes in the levels of lipid sn-positional
isomers
are associated with perturbation of the physiological environment
within the biological system. Consequently, knowing the concentrations
of these lipids holds significant importance for unraveling their
involvement in disease diagnosis and pathological mechanisms. However,
existing methods for lipid quantification often fall short in accuracy
due to the structural diversity and isomeric forms of lipids. To address
this challenge, we have developed an aziridine-based isobaric tag
labeling strategy that allows (i) differentiation and (ii) enhanced
relative quantification of lipid sn-positional isomers
from distinct samples in a single run. The methodology enabled by
aziridination, isobaric tag labeling, and lithiation has been applied
to various phospholipids, enabling the determination of the sn-positions of fatty acyl chains and enhanced relative
quantification. The analysis of Escherichia coli lipid extracts demonstrated the enhanced determination of the concentration
ratios of lipid isomers by measuring the intensity ratios of mass
reporters released from sn-positional diagnostic
ions. Moreover, we applied the method to the analysis of human colon
cancer plasma. Intriguingly, 17 PC lipid sn-positional
isomers were identified and quantified simultaneously, and among them,
7 showed significant abundance changes in the colon cancer plasma,
which can be used as potential plasma markers for diagnosis of human
colon cancer.