Characterization of cardiolipins and their oxidation products by LC–MS analysis

• Oxidizable polyunsaturated cardiolipins in eukaryotes.
• Lipidomics/oxidative lipidomics of cardiolipins.
• Analysis of oxygenated CL in cells and tissues.
• CL oxidation in model systems.

Cardiolipins, a class of mitochondria-specific lipid molecules, is one of the most unusual and ancient phospholipids found in essentially all living species. Typical of mammalian cells is the presence of vulnerable to oxidation polyunsaturated fatty acid resides in CL molecules. The overall role and involvement of cardiolipin oxidation (CLox) products in major intracellular signaling as well as extracellular inflammatory and immune responses have been established. However, identification of individual peroxidized molecular species in the context of their ability to induce specific biological responses has not been yet achieved. This is due, at least in part, to technological difficulties in detection, identification, structural characterization and quantitation of CLox associated with their very low abundance and exquisite diversification. This dictates the need for the development of new methodologies for reliable, sensitive and selective analysis of both CLox. LC–MS-based oxidative lipidomics with high mass accuracy instrumentation as well as new software packages are promising in achieving the goals of expedited and reliable analysis of cardiolipin oxygenated species in biosamples.