Unveiling Lipid Dysregulation: Lipidomics of Mouse Brain and Isolated Myelin in Niemann - Pick Disease Type C1

Niemann-Pick Disease Type C1 (NPC1) is a fatal, neurodegenerative disorder, characterized by lysosomal lipid accumulation and dysmyelination. Previous studies have documented some lipid abnormalities in the null mouse (Npc1-/-) focused on the whole brain and liver. However, the specific lipidomic alterations in severely affected brain regions, such as cerebellum and isolated myelin remain understudied. We present a comprehensive LC-MS-based lipidomic analysis of the cerebellum and cortex of Npc1-/- mice during disease progression stages, along with the first comprehensive characterization of the myelin lipidome in NPC1 disease. Our results reveal that the cerebellum accumulates lipid species, including sphingolipids and glycerophospholipids progressively, while the cortex shows an overall decline in lipid levels, indicating region-specific lipid dysregulation. Notably, bis(monoacylglycero)phosphates and their precursors--including lysophosphatidylglycerol and hemibismonoacylglycerophosphate exhibit significant accumulation, with a preference for docosahexaenoic acid (DHA)-containing species. Despite known cholesterol storage defects in NPC1, we observed reduced free cholesterol levels in both regions, which we attribute to myelin loss. Myelin-specific lipidomics demonstrated extensive dysregulation, particularly in cortical myelin, including severe losses in sulfatides, ether-lipids, and acylcarnitine, alongside striking accumulation of hydroxy-ceramides. These findings identify novel lipid alterations in brain subregions and myelin, offering critical insight into the lipid perturbations under the loss of NPC1, and highlight lipid targets that may be crucial for therapeutic intervention and biomarker development.