Opielka M., Urbanowicz K., Konieczna-Wolska K., Müller E., Krajewski O., Feucherolles M., Zhou Q., Bienkowski M., Frache G., Hopf C., Schirmer L., Rutkowska A., Smolenski R.T.
Journal of Lipid Research, vol. 66, n° 11, art. no. 100912, 2025
Myelin pathology in demyelinating diseases is accompanied by lipid remodeling that remains challenging to characterize at the spatial level using traditional mass spectrometry. We developed an optimized AP-MALDI-Orbitrap MSI pipeline, incorporating sample preparation improvements and mass recalibration, to investigate lipid dynamics in the cuprizone (CPZ) mouse model of demyelination. Dual-modality, untargeted lipid profiling was performed to map spatially resolved lipid alterations during demyelination and spontaneous remyelination in two key brain areas of male mice: corpus callosum (CC) and cortex (Ctx), with lipid identifications benchmarked against 4D-LC-TIMS-MS/MS. Demyelinated regions were identified using Black Gold II staining. Using 1 ppm mass tolerance, we annotated 154 and 133 lipids at the sum-composition level in CC and Ctx, respectively, with 60% validated by LC-MS/MS. Spatial lipid profiling revealed CPZ-induced alterations in sphingolipids, sulfatides, and glycerophospholipids, supported by reanalysis of a published snRNA-seq dataset from a mouse CPZ model. Long-chain ceramides (Cer) and hexosylceramides (HexCer) were reduced in demyelinated regions, with partial, region-specific recovery during remyelination. Short-chain sulfatides (SHexCer), sphingomyelins (SM), and seminolipids transiently increased in the CC during demyelination, while long-chain sulfatides decreased in both CC and Ctx. Additionally, we observed demyelination-induced upregulation of polyunsaturated glycerophospholipids in CC and phosphatidylinositols (PI) in cortex. Lipid subclass changes emerged as reliable markers of both demyelination and remyelination in the mouse brain. Region-specific alterations in lipid metabolism provide new insights into the processes of de- and remyelination. Notably, remyelinated fibers have a distinct lipid profile compared to intact myelin, suggesting that lipid-based therapeutic strategies could improve myelin repair.
