The N-glycome of human embryonic stem cells
- Equal contributors
1 Glykos Finland Ltd, Helsinki, Finland
2 Biomedicum Stem Cell Center, University of Helsinki, Helsinki, Finland
3 Family Federation of Finland, Infertility Clinic, Helsinki, Finland
4 Finnish Red Cross Blood Service, Helsinki, Finland
5 Program in Structural Biology and Biophysics, Institute of Biotechnology/NMR Laboratory, University of Helsinki, Helsinki, Finland
6 Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland
7 Current address: Nexstim Ltd., Helsinki, Finland
BMC Cell Biology 2009, 10:42 doi:10.1186/1471-2121-10-42Published: 2 June 2009
Complex carbohydrate structures, glycans, are essential components of glycoproteins, glycolipids, and proteoglycans. While individual glycan structures including the SSEA and Tra antigens are already used to define undifferentiated human embryonic stem cells (hESC), the whole spectrum of stem cell glycans has remained unknown. We undertook a global study of the asparagine-linked glycoprotein glycans (N-glycans) of hESC and their differentiated progeny using MALDI-TOF mass spectrometric and NMR spectroscopic profiling. Structural analyses were performed by specific glycosidase enzymes and mass spectrometric fragmentation analyses.
The data demonstrated that hESC have a characteristic N-glycome which consists of both a constant part and a variable part that changes during hESC differentiation. hESC-associated N-glycans were downregulated and new structures emerged in the differentiated cells. Previously mouse embryonic stem cells have been associated with complex fucosylation by use of SSEA-1 antibody. In the present study we found that complex fucosylation was the most characteristic glycosylation feature also in undifferentiated hESC. The most abundant complex fucosylated structures were Lex and H type 2 antennae in sialylated complex-type N-glycans.
The N-glycan phenotype of hESC was shown to reflect their differentiation stage. During differentiation, hESC-associated N-glycan features were replaced by differentiated cell-associated structures. The results indicated that hESC differentiation stage can be determined by direct analysis of the N-glycan profile. These results provide the first overview of the N-glycan profile of hESC and form the basis for future strategies to target stem cell glycans.