Biodistribution, Kinetics, and Efficacy of Highly Phosphorylated and Non-phosphorylated β-Glucuronidase in the Murine Model of Mucopolysaccharidosis VII

Mark S. Sands, Carole A. Vogler, Kevin K. Ohlemiller, Marie S. Roberts, Jeffrey H. Grubb, Beth Levy, William S. Sly

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Enzyme replacement therapy (ERT) has been shown to be effective at reducing the accumulation of undegraded substrates in lysosomal storage diseases. Most ERT studies have been performed with recombinant proteins that are mixtures of phosphorylated and non-phosphorylated enzyme. Because different cell types use different receptors to take up phosphorylated or non-phosphorylated enzyme, it is difficult to determine which form of enzyme contributed to the clinical response. Here we compare the uptake, distribution, and efficacy of highly phosphorylated and non-phosphorylated β-glucuronidase (GUSB) in the MPS VII mouse. Highly phosphorylated murine GUSB was efficiently taken up by a wide range of tissues. In contrast, non-phosphorylated murine GUSB was taken up primarily by tissues of the reticuloendothelial (RE) system. Although the tissue distribution was different, the half-lives of both enzymes in any particular tissue were similar. Both preparations of enzyme were capable of preventing the accumulation of lysosomal storage in cell types they targeted. An important difference in clinical efficacy emerged in that phosphorylated GUSB was more efficient than non-phosphorylated enzyme at preventing the hearing loss associated with this disease. These data suggest that both forms of enzyme contribute to the clinical responses of ERT in MPS VII mice but that enzyme preparations containing phosphorylated GUSB are more broadly effective than non-phosphorylated enzyme.

Original languageEnglish
Pages (from-to)43160-43165
Number of pages6
JournalJournal of Biological Chemistry
Volume276
Issue number46
DOIs
StatePublished - Nov 16 2001

Keywords

  • USA

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