Microscale Analysis of Glycosphingolipids from Schistosoma mansoni Cercariae

Glycosphingolipids are ubiquitous cell membrane components which play important roles in recognition processes and signal transduction, thus affecting many cellular functions [1-3]. Studies on specific functional roles of glycosphingolipids require detailed information on both carbohydrates as well as ceramide moieties. As glycolipids are often available in small amount only, we have developed a microscale approach for structural analysis of these compounds. The protocol is based on enzymatic digestion by sphingolipid ceramide N-deacylase in a two-phase liquid system [4]. Resulting lyso-glycosphingolipids were recovered from the aqueous phase and analysed by mass spectrometry, whereas released fatty acids were isolated from organic and aqueous phases and identified as methyl ester derivatives. Application of this methodology to distinct glycolipid fractions obtained from the cercarial life-cycle stage of the human parasitic helminth Schistosoma mansoni revealed clear differences in the ceramide compositions of ceramide monohexoside versus ceramide pentahexoside species carrying a Lewis X carbohydrate epitope. Whereas ceramide monohexosides were dominated by the preponderant presence of phytosphingosine species with 18-20 carbon atoms and fatty acids comprising 16 carbon atoms, respective ceramide pentahexoside-derived sphingoid bases represented predominantly sphinganine derivatives with 18-21 carbon atoms and fatty acids with 20-28 carbon atoms. Starting from 2.5 nmol of glycosphingolipids detailed structural information could be thus obtained.