Fig. 1

Negative ion mode MALDI-MS analysis of the lipid extracts of three PDO cell lines derived from PT19_03, PT19_06 and PT21_11 patients. A Lipid profiles acquired in negative ion mode by automatic acquisition. Lipid species can be grouped in two main ranges: the m/z range 700–900, where GPL and GPS species are present, and the m/z range 1100–1500, where minor peaks compatible with GSLs and CLs species are visible. B Two-dimensional principal component analysis (2D PCA) scores plot of the individual PDO cumulated spectra (525, 483 and 462, respectively) using 131 aligned peaks. Two principal components (PC) explained 79.28% of the variance of the data. In (C), we show the fragmentation pattern of ions with m/z 885.6, 778.5, 1088.5, and 1450 obtained by MS/MS analysis. m/z 885.6 corresponding to PI 38:4 was fragmented into the characteristic product ions with m/z 419.2, 283.1, and 240.8; m/z 778.5 was fragmented into ions with m/z 96.9 (hydrogen sulfate ion), m/z 258.7 (dehydrogenated galactose-sulfate) and m/z 240.7 (dehydrated galactose-sulfate), ions known to be representative signals of the ST head group and corresponding to ST d18:1-C16:0. The m/z 1088.6 ion corresponding to the GlcNAc-PI 38:4 species [15] was fragmented into product ions with m/z 443.9 (GlcNAc-myo-inositol-1,2-cyclic phosphate) and its dehydration product at m/z 425.7. These two ions are characteristic of the negative ion GlcNAc-PI spectra. Peaks at m/z 78.7, 152.7, and 282.9 are (phosphate), (glycerol-cyclic phosphate), and (stearate), respectively. m/z 1450.8 was fragmented into product ions with m/z 831.7, 751.7, 695.6, 697.6, 415.2, 417.5, 281, and 279 typical fragments of CL72:7, with the most intense peaks corresponding to linoleate (m/z 279), monoacylglycerol phosphatidate (m/z 415.2), and diacylglycerol phosphatidate (m/z 695.6)