The pharmacological chaperone 1-deoxynojirimycin increases the activity and lysosomal trafficking of multiple mutant forms of acid alpha-glucosidase.

Abstract

Pompe disease is a lysosomal storage disorder (LSD) caused by mutations in the gene that encodes acid alpha-glucosidase (GAA). Recently, small molecule pharmacological chaperones have been shown to increase protein stability and cellular levels for mutant lysosomal enzymes and have emerged as a new therapeutic strategy for the treatment of LSDs. In this study, we characterized the pharmacological chaperone 1-deoxynojirimycin (DNJ) on 76 different mutant forms of GAA identified in Pompe disease. DNJ significantly increased enzyme activity and protein levels for 16 different GAA mutants in patient-derived fibroblasts and in transiently transfected COS-7 cells. Additionally, DNJ increased the processing of these GAA mutants to their mature lysosomal forms, suggesting facilitated trafficking through the secretory pathway. Immunofluorescence microscopy studies showed increased colocalization of GAA with the lysosomal marker LAMP2 after incubation with DNJ, confirming increased lysosomal trafficking. Lastly, a GAA structural model was constructed based on the related eukaryotic glucosidase maltase-glucoamylase. The mutated residues identified in responsive forms of GAA are located throughout most of the structural domains, with half of these residues located in two short regions within the catalytic domain. Taken together, these data support further evaluation of DNJ as a potential treatment for Pompe disease in patients that express responsive forms of GAA.

• Authors: John J Flanagan, Barbara Rossi, Katherine Tang, Xiaoyang Wu, Kirsten Mascioli, Francesca Donaudy, Maria Rosaria Tuzzi, Federica Fontana, Maria Vittoria Cubellis, Caterina Porto, Elfrida Benjamin, David J Lockhart, Kenneth J Valenzano, Generoso Andria, Giancarlo Parenti, Hung V Do
• Journal: Human mutation (Hum Mutat) Vol. 30 Issue 12 Pg. 1683-92 (Dec 2009) ISSN: 1098-1004 [Electronic] United States
• PMID: 19862843 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Mutant Proteins
• Recombinant Proteins
• 1-Deoxynojirimycin
• GAA protein, human
• alpha-Glucosidases

Topics

• 1-Deoxynojirimycin (pharmacology)
• Adolescent
• Adult
• Animals
• COS Cells
• Chlorocebus aethiops
• Enzyme Stability (drug effects)
• Fibroblasts (drug effects, enzymology)
• Glycogen Storage Disease Type II (enzymology)
• Humans
• Infant
• Lysosomes (drug effects, enzymology)
• Models, Molecular
• Mutant Proteins (metabolism)
• Protein Structure, Secondary
• Protein Transport (drug effects)
• Recombinant Proteins (metabolism)
• alpha-Glucosidases (chemistry, metabolism)