SiaNAl can be efficiently incorporated in glycoproteins of human mesenchymal stromal cells by metabolic glycoengineering

Metabolic glycoengineering involves the stimulation of
cells with
functionalized monosaccharides. Glucosamine, galactosamine, and mannosamine
derivatives are commercially available, but their application may
lead to undirected (i.e., chemical) incorporation into proteins. However,
sialic acids are attached to the ends of complex sugar chains of glycoproteins,
which might be beneficial for cell surface modification via click
chemistry. Thus, we studied the incorporation of chemically synthesized
unnatural alkyne modified sialic acid (SiaNAl) into glycoproteins
of human telomerase-immortalized mesenchymal stromal cells (hMSC-TERT)
and we show that SiaNAl can be efficiently incorporated in glycoproteins
involved in signal transduction and cell junction.

代谢糖工程（Metabolic glycoengineering）指通过功能化单糖对细胞进行刺激。葡萄糖胺、半乳糖胺及甘露糖胺衍生物均已商品化，但这类衍生物的应用可能会导致蛋白发生非定向（即化学）掺入。然而，唾液酸附着于糖蛋白复合糖链的末端，这一特性或可为通过点击化学（click chemistry）实现细胞表面修饰提供有利条件。为此，本研究探究了化学合成的非天然炔基修饰唾液酸（SiaNAl）在人端粒酶永生化间充质基质细胞（hMSC-TERT）糖蛋白中的掺入情况，并证实SiaNAl可高效掺入参与信号转导与细胞连接的糖蛋白中。