The N-glycome of human embryonic stem cells.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Satomaa
Tero
T
Glykos Finland Ltd, Helsinki, Finland. tero.satomaa@glykos.fi
Heiskanen
Annamari
A
Mikkola
Milla
M
Olsson
Cia
C
Blomqvist
Maria
M
Tiittanen
Minna
M
Jaatinen
Taina
T
Aitio
Olli
O
Olonen
Anne
A
Helin
Jari
J
Hiltunen
Jukka
J
Natunen
Jari
J
Tuuri
Timo
T
Otonkoski
Timo
T
Saarinen
Juhani
J
Laine
Jarmo
J
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002454:Cell Differentiation; D015536:Down-Regulation; D053595:Embryonic Stem Cells / Q000737:chemistry* / Q000166:cytology*; D005643:Fucose / Q000737:chemistry; D054794:Glycomics; D006801:Humans; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D011134:Polysaccharides; D005643:Fucose