Rapid and sensitive LC-ESI-MS of gangliosides

Gangliosides are a class of sphingolipids characterized by a ceramide lipid chain attached to an anionic oligosaccharide moiety that varies in complexity based on the level of sialylation. Heterogeneity in the oligosaccharide chain of gangliosides is a direct result of the monosaccharide structure, content, sequence, and connections. Gangliosides are highly concentrated in the central nervous system, and are cell type-specific as well as development-dependent and their quantities and species can undergo drastic changes during cell differentiation. Specific localization of gangliosides also allows for interaction with a variety of bioeffectors, including glycoproteins, antibodies, peptide hormones, and growth factors. There are currently no rapid analytical assays capable of identifying and quantifying gangliosides. The aim of this study is to establish a reliable chromatographic mass spectrometry based assay capable of profiling ganglioside levels in complex biological samples at high sensitivity. We describe here a chromatographic method using an amino column on which the separation is based on hydrophilic interaction with the sugar moiety of gangliosides. Several gangliosides, including GM1-3, GD1a,b, GD2-3, and GT1a,b, were efficiently separated in less than 10 min at a limit of detection ranging between 10-50 pg on column with a concentration dynamic range extending over 4 orders of magnitude. The developed method allowed the sensitive quantitation of gangliosides derived from the blood serum of patients with different esophagus diseases, including, adenocarcinoma, high-grade dysplasia, and Barrett's.