Analysis of Ganglioside Distribution in Mammalian Brain Tissue by Direct profiling and micro-extraction studies using MALDI-TOF/MS.

摘要

Gangliosides are a family of sphingoglycolipids (synthesized from ceramide) and are characterized by the presence of an oligosaccharide chains with sialic acid moieties. These lipids are constituents of the outer layer of plasma membranes and are particularly abundant in the central nervous system (CNS) and peripheral nervous system (PNS). Gangliosides metabolic or immunological alterations may have serious pathological consequences in the CNS such as lysosomal diseases [1] and are also implicates in Alzheimer disease [2]. Gangliosides distribution was studied using a MALDI-TOF/TOF (GM_(1)a, GD_(1)a, GD_(1)b, and GT_(1)b) [3] [4]. Recent studies have shown that eicosasphingosine species of gangliosides (d20:1 sphingo?d base) are mainly localized in the dentate gyrus of the mouse brain [5] [6]. In this study, we have tested a new matrix preparation (2,6-dihydroxyacetophenone (DHA)/ammonium sulfate/Heptafluorobutyric acid (HFBA)) to maximize the detection of all ganglioside species, while limiting the formation of salt adducts by addition of ammonium sulfate, and increasing the DHA stability in vacuum by addition of HFBA. Our results, in both extracted samples and in whole tissue sections using negative ion reflectron and linear mode, show differences in localization in several brain regions depending on the sphingo?d base associated gangliosides.