Deep Profiling of Porcine Brain Gangliosides Enabled by TiO2 Magnetic Nanoparticle-Based Enrichment and Advanced Lipidomic Analysis

Abstract

Gangliosides are a class of glycosphingolipids highly enriched in the central nervous system which play key roles in neurological functions and pathologies. Deep profiling of gangliosides remains challenging due to their low abundance, high structural complexity, and matrix effect. Recently, we have developed a method for cellular ganglioside enrichment using TiO2 magnetic nanoparticles; however, the large difference within the brain lipidome demands significant modification of the method. Herein, we introduce a tailored enrichment procedure which selectively depletes major brain-specific interfering lipids, thereby allowing the enrichment of gangliosides with up to four sialic acid residues. Furthermore, the integration of amide-hydrophilic interaction liquid chromatography with trapped ion mobility spectrometry and tandem mass spectrometry greatly facilitates the discovery of new ganglioside structures. Applied to porcine brain total lipid extract, we achieve the identification 239 species across 40 subclasses, including newly discovered GD1c and O-Ac-GD1c, with 184 of them characterized at the chain composition level. Compared to the fewer than 15 subclasses identified in brain gangliosides using non-enriched approaches, our data present the most extensive structural atlas of brain gangliosides reported to date. This approach holds promise for investigating brain ganglioside metabolism involved in neurodevelopment, neurodegeneration, and other neurological contexts.