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Carbohydrate-remodelled acid alpha-glucosidase with higher affinity for the cation-independent mannose 6-phosphate receptor demonstrates improved delivery to muscles of Pompe mice.
Biochem J. 2005 Aug 01; 389(Pt 3):619-28.BJ

Abstract

To enhance the delivery of rhGAA (recombinant GAA, where GAA stands for acid alpha-glucosidase) to the affected muscles in Pompe disease, the carbohydrate moieties on the enzyme were remodelled to exhibit a high affinity ligand for the CI-MPR (cation-independent M6P receptor, where M6P stands for mannose 6-phosphate). This was achieved by chemically conjugating on to rhGAA, a synthetic oligosaccharide ligand bearing M6P residues in the optimal configuration for binding the receptor. The carbonyl chemistry used resulted in the conjugation of approx. six synthetic ligands on to each enzyme. The resulting modified enzyme [neo-rhGAA (modified recombinant human GAA harbouring synthetic oligosaccharide ligands)] displayed near-normal specific activity and significantly increased affinity for the CI-MPR. However, binding to the mannose receptor was unaffected despite the introduction of additional mannose residues in neo-rhGAA. Uptake studies using L6 myoblasts showed neo-rhGAA was internalized approx. 20-fold more efficiently than the unmodified enzyme. Administration of neo-rhGAA into Pompe mice also resulted in greater clearance of glycogen from all the affected muscles when compared with the unmodified rhGAA. Comparable reductions in tissue glycogen levels in the Pompe mice were realized using an approx. 8-fold lower dose of neo-rhGAA in the heart and diaphragm and an approx. 4-fold lower dose in the skeletal muscles. Treatment of older Pompe mice, which are more refractory to enzyme therapy, with 40 mg/kg neo-rhGAA resulted in near-complete clearance of glycogen from all the affected muscles as opposed to only partial correction with the unmodified rhGAA. These results demonstrate that remodelling the carbohydrate of rhGAA to improve its affinity for the CI-MPR represents a feasible approach to enhance the efficacy of enzyme replacement therapy for Pompe disease.

Authors+Show Affiliations

Genzyme Corporation, 31 New York Avenue, Framingham, MA 01701-9322, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15839836

Citation

Zhu, Yunxiang, et al. "Carbohydrate-remodelled Acid Alpha-glucosidase With Higher Affinity for the Cation-independent Mannose 6-phosphate Receptor Demonstrates Improved Delivery to Muscles of Pompe Mice." The Biochemical Journal, vol. 389, no. Pt 3, 2005, pp. 619-28.
Zhu Y, Li X, McVie-Wylie A, et al. Carbohydrate-remodelled acid alpha-glucosidase with higher affinity for the cation-independent mannose 6-phosphate receptor demonstrates improved delivery to muscles of Pompe mice. Biochem J. 2005;389(Pt 3):619-28.
Zhu, Y., Li, X., McVie-Wylie, A., Jiang, C., Thurberg, B. L., Raben, N., Mattaliano, R. J., & Cheng, S. H. (2005). Carbohydrate-remodelled acid alpha-glucosidase with higher affinity for the cation-independent mannose 6-phosphate receptor demonstrates improved delivery to muscles of Pompe mice. The Biochemical Journal, 389(Pt 3), 619-28.
Zhu Y, et al. Carbohydrate-remodelled Acid Alpha-glucosidase With Higher Affinity for the Cation-independent Mannose 6-phosphate Receptor Demonstrates Improved Delivery to Muscles of Pompe Mice. Biochem J. 2005 Aug 1;389(Pt 3):619-28. PubMed PMID: 15839836.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Carbohydrate-remodelled acid alpha-glucosidase with higher affinity for the cation-independent mannose 6-phosphate receptor demonstrates improved delivery to muscles of Pompe mice. AU - Zhu,Yunxiang, AU - Li,Xuemei, AU - McVie-Wylie,Alison, AU - Jiang,Canwen, AU - Thurberg,Beth L, AU - Raben,Nina, AU - Mattaliano,Robert J, AU - Cheng,Seng H, PY - 2005/4/21/pubmed PY - 2005/11/5/medline PY - 2005/4/21/entrez SP - 619 EP - 28 JF - The Biochemical journal JO - Biochem. J. VL - 389 IS - Pt 3 N2 - To enhance the delivery of rhGAA (recombinant GAA, where GAA stands for acid alpha-glucosidase) to the affected muscles in Pompe disease, the carbohydrate moieties on the enzyme were remodelled to exhibit a high affinity ligand for the CI-MPR (cation-independent M6P receptor, where M6P stands for mannose 6-phosphate). This was achieved by chemically conjugating on to rhGAA, a synthetic oligosaccharide ligand bearing M6P residues in the optimal configuration for binding the receptor. The carbonyl chemistry used resulted in the conjugation of approx. six synthetic ligands on to each enzyme. The resulting modified enzyme [neo-rhGAA (modified recombinant human GAA harbouring synthetic oligosaccharide ligands)] displayed near-normal specific activity and significantly increased affinity for the CI-MPR. However, binding to the mannose receptor was unaffected despite the introduction of additional mannose residues in neo-rhGAA. Uptake studies using L6 myoblasts showed neo-rhGAA was internalized approx. 20-fold more efficiently than the unmodified enzyme. Administration of neo-rhGAA into Pompe mice also resulted in greater clearance of glycogen from all the affected muscles when compared with the unmodified rhGAA. Comparable reductions in tissue glycogen levels in the Pompe mice were realized using an approx. 8-fold lower dose of neo-rhGAA in the heart and diaphragm and an approx. 4-fold lower dose in the skeletal muscles. Treatment of older Pompe mice, which are more refractory to enzyme therapy, with 40 mg/kg neo-rhGAA resulted in near-complete clearance of glycogen from all the affected muscles as opposed to only partial correction with the unmodified rhGAA. These results demonstrate that remodelling the carbohydrate of rhGAA to improve its affinity for the CI-MPR represents a feasible approach to enhance the efficacy of enzyme replacement therapy for Pompe disease. SN - 1470-8728 UR - https://www.unboundmedicine.com/medline/citation/15839836/Carbohydrate_remodelled_acid_alpha_glucosidase_with_higher_affinity_for_the_cation_independent_mannose_6_phosphate_receptor_demonstrates_improved_delivery_to_muscles_of_Pompe_mice_ L2 - https://portlandpress.com/biochemj/article-lookup/doi/10.1042/BJ20050364 DB - PRIME DP - Unbound Medicine ER -