Alteration of sugar chains on alpha(1)-acid glycoprotein secreted following cytokine stimulation of HuH-7 cells in vitro.
In inflammation, hepatocytes secrete several proteins into serum, the so-called acute phase proteins. In addition to increased serum levels of alpha(1)-acid glycoprotein (AGP), there are also changes in the composition of its sugar chains. To investigate the cytokine-stimulated alteration of sugar chains on AGP, we cultured the human hepatoma cell line HuH-7 cells in serum-free medium (IS-RPMI) with and without IL-1beta and IL-6, and analyzed AGP secretion into the medium. AGP was increased during stimulation with both IL-1beta and IL-6, although the effect of IL-1beta was more pronounced. Lectin-binding assay for secreted AGP also indicated significant increases in the binding activities to Aleuria aurantia lectin (AAL), Sambucus sieboldiana agglutinin (SSA), and concanavalin-A (ConA). In particular, AAL binding activity increased with higher expression of the sialyl Lewis X (sLe(X)) antigen, NeuAc alpha2-3 Gal beta1-4 (Fuc alpha1-3) GlcNAc-R. Thus, the increase in AGP fucosylation may be correlated with the increase of sLe(X). The present results indicate that the serum-free culture of HuH-7 cells provides a useful model for investigating the secretion of proteins from hepatocytes, and the effects of cytokines on the changes in sugar chains of glycoproteins in vitro.
Azuma
Y
Y
Department of Clinical Chemistry, School of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba, Japan. yutaro@phar.toho-u.ac.jp
Murata
M
M
Matsumoto
K
K
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006528:Carcinoma, Hepatocellular; D016895:Culture Media, Serum-Free; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D007700:Kinetics; D037102:Lectins; D008113:Liver Neoplasms; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D009961:Orosomucoid / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism; D000080506:Sialyl Lewis X Antigen; D014407:Tumor Cells, Cultured
D016895:Culture Media, Serum-Free; D007375:Interleukin-1; D015850:Interleukin-6; D037102:Lectins; D009844:Oligosaccharides; D009961:Orosomucoid; D000080506:Sialyl Lewis X Antigen