A Glycoengineered Enzyme with Multiple Mannose-6-Phosphates Is Internalized into Diseased Cells to Restore Its Activity in Lysosomes.

In this study we developed an efficient method to prepare glycoengineered β-N-acetylhexosaminidase containing multiple mannose-6-phosphates (M6Ps) by combining genetic code expansion with bioorthogonal ligation techniques. We found that multiple M6P-conjugated enzymes were produced with a high efficiency by using combined techniques. Importantly, glycoengineered enzymes entered lysosomes of patient-derived primary cells, which lack endogenous lysosomal β-N-acetylhexosaminidase, more readily than commercialized human β-hexosaminidase. Moreover, glycoengineered enzymes successfully removed GM2-ganglioside stored in lysosomes of diseased cells, indicating that its activity is restored in diseased cells. We also synthesized and applied a lysosome-targeting fluorogenic substrate to monitor endogenous and supplemental glycoengineered β-N-acetylhexosaminidase activities in lysosomes. The results of this study indicate that the present strategy, which relies on genetic code expansion and bioorthogonal ligation techniques, is highly attractive to generate multi-M6P-containing lysosomal enzymes that can be used to study lysosomal storage disorders associated with lysosomal enzyme deficiencies.