Cost-effective workflow for efficient unsaturated lipidomics enabled by a novel ion chemistry

About This Grant

Abstract Isomerism in carbon-carbon double bond (C=C) position is common in unsaturated lipids. Tracking shifting lipid C=C isomerism in lipids not only sheds light on the complexity of the biological lipidome but also enables the detection of minor, yet significant, perturbations in lipid isomer ratios caused by certain disease conditions. Despite the significant progress made to enable resolution of lipid C=C positions, the existing technologies have their limitations, making it still challenging to do C=C isomeric lipid analysis in a cost-effective and high throughput manner. We recently discovered a novel ion chemistry, OzNOxESI, in the ionization source of a mass spectrometer. The reaction is sufficiently fast for coupling with LC-MS based lipidomics workflows, and the OzNOx adducts of unsaturated lipids produce ions diagnostic of C=C position under collisional induced dissociation, which provides a simple, easily accessible, and cost-effective solution for determining lipid C=C position with minimal modification to a mass spectrometer. In this project, we plan to extend this novel ion chemistry beyond phospholipids to be applicable to all lipid classes, particularly the structurally more complex glycerolipids and sphingolipids, and investigate how the intensity of C=C diagnostic ions changes with respect to location on the fatty acyl chain, aiming for an algorithm that can correct C=C position induced-ion intensity differences for more accurate quantification of C=C regioisomeric lipids. We also plan to establish safe, efficient, and robust OzNOxESI on newer generation ion sources, making this capability available on newer mass spectrometers. In addition, we plan to develop a software suite to manage all data processing needs in lipid analysis, making it a one-stop solution for identification and quantification of lipids with structural details at the C=C regioisomer level. To achieve these goals, lipid standards and lipid extracts from cell lines, animal tissues, and human plasma will be thoroughly investigated as representative biological samples. The outcomes of this project can democratize advanced lipidomics capabilities and expedite the investigation of lipid unsaturation in biology and disease.