title: Early stage fetal neocortex exhibits a complex ganglioside profile as revealed by high resolution tandem mass spectrometry.
abstract: In this study we report on the first mass spectrometric (MS) investigation of gangliosides and preliminary assessment of the expression and structure in normal fetal neocortex in early developmental stages: 14th (Neo14) and 16th (Neo16) gestational weeks. Ganglioside analysis was carried out using a hybrid quadrupole time-of-flight (QTOF) MS with direct sample infusion by nanoelectrospray ionization (nanoESI) in the negative ion mode. Under optimized conditions a large number of glycoforms i.e. 75 in Neo14 and 71 in Neo16 mixtures were identified. The ganglioside species were found characterized by a high diversity of the ceramide constitution, an elevated sialylation degree (up to pentasialylated gangliosides-GP1) and sugar cores modified by fucosylation (Fuc) and acetylation (O-Ac). Direct comparison between Neo14 and Neo16 revealed a prominent expression of monosialylated structures in the Neo16 as well as the presence of a larger number of polysialylated species in Neo14 which constitutes a clear marker of rapid development-dependant changes in the sialylation. Also the MS screening results highlighted that presumably O-acetylation process occurs faster than fucosylation. CID MS/MS under variable collision energy applied for the first time for structural analysis of a fucosylated pentasialylated species induced an efficient fragmentation with generation of ions supporting Fuc-GP1d isomer in early stage fetal brain neocortex.
authors.forename: Roxana M
authors.initials: RM
authors.lastname: Ghiulai
authors.forename: Mirela
authors.initials: M
authors.lastname: Sarbu
authors.forename: Željka
authors.initials: Ž
authors.lastname: Vukelić
authors.forename: Constantin
authors.initials: C
authors.lastname: Ilie
authors.forename: Alina D
authors.initials: AD
authors.lastname: Zamfir
mesh_terms: D000107:Acetylation; D003720:Densitometry / Q000379:methods; D005732:Gangliosides / Q000032:analysis / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D036103:Nanotechnology; D019579:Neocortex / Q000196:embryology* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D005732:Gangliosides