Increased alpha2,3-sialylation and hyperglycosylation of N-glycans in embryonic rat cortical neurons during camptothecin-induced apoptosis.
Alterations in the glycan chains of cell surface glycoconjugates are frequently involved biological processes such as cell-cell interaction, cell migration, differentiation and development. Cultured embryonic (E18) rat cortical neurons underwent apoptosis in response to camptothecin, and lectin histochemistry showed that binding to apoptotic neurons of FITC-conjugated Maackia amurensis agglutinin (MAA), which is specific for terminal alpha2,3-sialic acid residues, increased progressively with increasing concentrations of camptothecin. Analysis of the total proteins of apoptotic neurons by SDS-PAGE, and lectin blotting using HRP-labeled MAA, revealed that the expression of terminal alpha2,3-sialic acid residues on an unknown protein with an apparent molecular mass of 25.6 kDa also increased in apoptotic neurons. NP-HPLC analysis of the total cellular N-glycans of normal and apoptotic neurons demonstrated that the expression of structurally simpler biantennary types of N-glycans fell by 49% during apoptosis whereas the more branched triantennary types of N-glycans with terminal sialic acid residues increased by up to 59%. These results suggest that increased surface expression of alpha2,3-sialic acid residues and hyperglycosylation of N-glycans is a common feature of cellular responses to changes in cell physiology such as tumorigenesis and apoptosis.
Kim
Sung-Min
SM
Department of Biotechnology and Biomaterial Engineering Center, The Catholic University of Korea, Bucheon 420-743, Korea.
Lee
Jung-Sun
JS
Lee
Yoon-Hee
YH
Kim
Woo-Jung
WJ
Do
Su-Il
SI
Choo
Young-Kug
YK
Park
Yong-Il
YI
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002166:Camptothecin / Q000494:pharmacology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology*; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D009419:Nerve Tissue Proteins / Q000302:isolation & purification; D009474:Neurons / Q000187:drug effects*; D011134:Polysaccharides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012794:Sialic Acids / Q000378:metabolism*
D009419:Nerve Tissue Proteins; D011134:Polysaccharides; D012794:Sialic Acids; D002166:Camptothecin