posted on 2022-12-27, 19:05authored byKaterina
V. Djambazova, Martin Dufresne, Lukasz G. Migas, Angela R. S. Kruse, Raf Van de Plas, Richard M. Caprioli, Jeffrey M. Spraggins
Gangliosides are acidic glycosphingolipids, containing
ceramide
moieties and oligosaccharide chains with one or more sialic acid residue(s)
and are highly diverse isomeric structures with distinct biological
roles. Matrix-assisted laser desorption/ionization imaging mass spectrometry
(MALDI IMS) enables the untargeted spatial analysis of gangliosides,
among other biomolecules, directly from tissue sections. Integrating
trapped ion mobility spectrometry with MALDI IMS allows for the analysis
of isomeric lipid structures in situ. Here, we demonstrate the gas-phase
separation and identification of disialoganglioside isomers GD1a and
GD1b that differ in the position of a sialic acid residue, in multiple
samples, including a standard mixture of both isomers, a biological
extract, and directly from thin tissue sections. The unique spatial
distributions of GD1a/b (d36:1) and GD1a/b (d38:1) isomers were determined
in rat hippocampus and spinal cord tissue sections, demonstrating
the ability to structurally characterize and spatially map gangliosides
based on both the carbohydrate chain and ceramide moieties.