Abstract

Mesenchymal Stem cells (MSCs) are multipotent stromal cells that have a great potential to treat incurable diseases such as skeletal diseases and cardiovascular diseases. One of the challenges in MSCs therapy is to deliver MSCs to target tissues like heart and bone by systemic infusion. Some studies revealed that MSCs' low engraftment efficiency may be due to the lack of relevant cell-surface carbohydrates such as sialyl Lewis X (SLeX), which act as selectin ligands, and which have been shown to enhance the targeted migration of MSCs in previous research. Thus, we aimed to develop a methodology to synthesize a cell-surface-attachable SLeX conjugate and anchor it on the surface of live cells via linkage to cell-surface proteins. In this study, we employed an enzymatic synthesis pathway and successfully produced a SLeX-PEG3-Azide conjugate. We also added a cell surface labeling group NHS-ester on the azide tail of the SLeX-PEG3-Azide conjugate using click chemistry which is bio-orthogonal and compatible with living cells. Through our study, we built up a new method of synthesis of cell surface adhesive agent SLeX and carried out preliminary tests towards establishing a cell-labeling method to attach the molecule onto cell-surfaces. Compared with previous studies, our methodology is not restricted to existing precursors of SLeX on cell surfaces and it is also more economical by using enzymatic synthesis with glycosyltransferases that are easily produced by recombinant expression in E. coli.