The pharmacological chaperone 1-deoxynojirimycin increases the activity and lysosomal trafficking of multiple mutant forms of acid alpha-glucosidase.
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.
Amicus Therapeutics Inc., Cranbury, New Jersey 08512, USA.
John J
JJ
Flanagan
Barbara
B
Rossi
Katherine
K
Tang
Xiaoyang
X
Wu
Kirsten
K
Mascioli
Francesca
F
Donaudy
Maria Rosaria
MR
Tuzzi
Federica
F
Fontana
Maria Vittoria
MV
Cubellis
Caterina
C
Porto
Elfrida
E
Benjamin
David J
DJ
Lockhart
Kenneth J
KJ
Valenzano
Generoso
G
Andria
Giancarlo
G
Parenti
Hung V
HV
Do
D017485:1-Deoxynojirimycin / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004795:Enzyme Stability / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006009:Glycogen Storage Disease Type II / Q000201:enzymology; D006801:Humans; D007223:Infant; D008247:Lysosomes / Q000187:drug effects* / Q000201:enzymology*; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism*; D017433:Protein Structure, Secondary; D021381:Protein Transport / Q000187:drug effects; D011994:Recombinant Proteins / Q000378:metabolism; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism*
D050505:Mutant Proteins; D011994:Recombinant Proteins; D017485:1-Deoxynojirimycin; C509951:GAA protein, human; D000520:alpha-Glucosidases