KCS

Polyglycerophopholipids (PGPLs) are divided into phospholipids (PLs) containing two gylcerols including phosphatidylglycerol (PG), bis(monoacylglycero)phosphate (BMP), hemi BMP, and bis(diacylglycero)phosphate (BDP), and PLs with three glycerols such as cardiolipin (CL), monolysocardiolipin (MLCL), and dilysocardiolipin (DLCL). PGPLs are synthesized from PG and closely related to each other. Since PGPLs have been reported to be associated with neurodegenerative diseases, accurate determination of these lipids is important. Isotope-labeled methylation (ILM) method using (trimethylsilyl)diazomethane (TMSD) can be utilized for relative quantitation of lipids without the addition of internal standard lipids. In addition, many lipids of trace amount could be detected by ILM method with low detection limit. In this study, analysis of PGPLs with ILM method was carried out using nUHPLC-ESI-MS/MS. The collision-induced dissociation (CID) experiments was conducted for the methylated standard PGPLs. The efficiency of methylation for these lipids was found to be > 97% and the degree of methylation was dependent on the number of phosphate groups (1: PG, BMP, Hemi BMP and BDP, 2: CL, MLCL and DLCL). PG and BMP, which are geometrical isomers, and three isomers of BMP can be resolved from each other. A good linear relationship between experimental mixing ratio and calculated peak area of H-/D- methylated lipids were observed. This method was applied to the investigation of PGPLs from a neuronal cell line (SH-SY5Y) which was treated with some drugs, commonly used for the Parkinson’s disease model, were quantitatively analyzed.