Enhanced sialylation of albumin-erythropoietin through increased synthesis of UDP-N-acetylglucosamine in CHO cell culture

초록

Terminal sialic acid residues of N-linked glycan are major factor to determine half-life of glycoproteins. So, it is important to increase sialic acid contents of glycoprotein for the extension of half-life. There was a lot of efforts to maximize sialylation of various glycoproteins. One of the strategies is supplementation of glycan precursors in cell cultures. However, further research should be conducted according to the kinds of target protein and cell line because results of the feeding strategy are different. For that reason, in this study, uridine, N-acetylglucosamine (GlcNAc) and Mn2+ were added in Chinese hamster ovary (CHO) cell cultures producing albumin-erythropoietin (Alb-EPO). Uridine and GlcNAc were supplemented to increase the synthesis of UDP-GlcNAc. Mn2+ was added as a form of MnCl2 which act as a coenzyme of several glycosyltransferases to increase the sialylation of Alb-EPO. Optimization of the feeding strategy was performed by using response surface methodology (RSM). Feeding concentration of uridine was 2 mM to 10 mM, GlcNAc was 5 mM to 15 mM, and MnCl2 was fixed at 2 μM. As a result, uridine and GlcNAc showed a negative impact on IVCD(약자에 대한 full name 필요) of CHO cell culture and productivity of Alb-EPO. GlcNAc affected more negatively than uridine. However, titer of Alb-EPO was observed at similar level to control and even sialic acid content was increased. In conclusion, this feeding strategy of uridine, GlcNAc, and MnCl2 was found to enhance the sialylation of Alb-EPO in CHO cell culture.