title: Pharmacological enhancement of α-glucosidase by the allosteric chaperone N-acetylcysteine.
abstract: Pompe disease (PD) is a metabolic myopathy due to the deficiency of the lysosomal enzyme α-glucosidase (GAA). The only approved treatment for this disorder, enzyme replacement with recombinant human GAA (rhGAA), has shown limited therapeutic efficacy in some PD patients. Pharmacological chaperone therapy (PCT), either alone or in combination with enzyme replacement, has been proposed as an alternative therapeutic strategy. However, the chaperones identified so far also are active site-directed molecules and potential inhibitors of target enzymes. We demonstrated that N-acetylcysteine (NAC) is a novel allosteric chaperone for GAA. NAC improved the stability of rhGAA as a function of pH and temperature without disrupting its catalytic activity. A computational analysis of NAC-GAA interactions confirmed that NAC does not interact with GAA catalytic domain. NAC enhanced the residual activity of mutated GAA in cultured PD fibroblasts and in COS7 cells overexpressing mutated GAA. NAC also enhanced rhGAA efficacy in PD fibroblasts. In cells incubated with NAC and rhGAA, GAA activities were 3.7-8.7-fold higher than those obtained in cells treated with rhGAA alone. In a PD mouse model the combination of NAC and rhGAA resulted in better correction of enzyme activity in liver, heart, diaphragm and gastrocnemia, compared to rhGAA alone.
authors.affiliation: Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Porto
authors.forename: Maria C
authors.initials: MC
authors.lastname: Ferrara
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Meli
authors.forename: Emma
authors.initials: E
authors.lastname: Acampora
authors.forename: Valeria
authors.initials: V
authors.lastname: Avolio
authors.forename: Margherita
authors.initials: M
authors.lastname: Rosa
authors.forename: Beatrice
authors.initials: B
authors.lastname: Cobucci-Ponzano
authors.forename: Giorgio
authors.initials: G
authors.lastname: Colombo
authors.forename: Marco
authors.initials: M
authors.lastname: Moracci
authors.forename: Generoso
authors.initials: G
authors.lastname: Andria
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Parenti
mesh_terms: D000111:Acetylcysteine / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002522:Chlorocebus aethiops; D004795:Enzyme Stability / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006009:Glycogen Storage Disease Type II / Q000188:drug therapy; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D018832:Molecular Chaperones / Q000494:pharmacology / Q000627:therapeutic use; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism* / Q000627:therapeutic use*
chemical_list: D018832:Molecular Chaperones; D000520:alpha-Glucosidases; D000111:Acetylcysteine