Increased Sialylation of Albumin-Erythropoietin by Enhancing the Synthesis of UDP-NAcetylglucosamine in CHO Cell Cultures

초록

Since terminal sialic acid residue of N-glycan affects the half-life of glycoproteins, various strategies have been developed to maximize sialic acid contents of various glycoproteins. In particular, the addition of glycosylation-related precursors can effectively enhance the sialylation of glycoproteins. However, this strategy was known to be cell line and product specific. For these reasons, uridine, N-acetylglucosamine (GlcNAc), and manganese chloride were added to Chinese hamster ovary (CHO) cell cultures in this study. Uridine and GlcNAc were supplemented to increase the synthesis of UDP-GlcNAc. In addition, manganese chloride, as a coenzyme of several glycosyltransferases, was added to increase the sialylation of albumin-erythropoietin (Alb-EPO). Response surface methodology was used to optimize the feeding strategy. Feeding concentration of uridine was 2 mM to 10 mM, GlcNAc was 5 mM to 15 mM, and manganese chloride was fixed at 2 μM. as a result, uridine and GlcNAc showed negative impacts on both cell growth and production of Alb-EPO, while manganese chloride did not show any effect on culture performance. However, sialic acid content was increased up to 2-fold when precursors were present in culture medium. These results demonstrate that the combined feeding of uridine, GlcNAc, and manganese chloride can effectively enhance the sialylation of Alb-EPO in CHO cell cultures.