title: Transgenic mouse expressing human mutant alpha-galactosidase A in an endogenous enzyme deficient background: a biochemical animal model for studying active-site specific chaperone therapy for Fabry disease.
abstract: Fabry disease is an inborn error of glycosphingolipid metabolism caused by the deficiency of lysosomal alpha-galactosidase A (alpha-Gal A). We have established transgenic mice that exclusively express human mutant alpha-Gal A (R301Q) in an alpha-Gal A knock-out background (TgM/KO mice). This serves as a biochemical model to study and evaluate active-site specific chaperone (ASSC) therapy for Fabry disease, which is specific for those missense mutations that cause misfolding of alpha-Gal A. The alpha-Gal A activities in the heart, kidney, spleen, and liver of homozygous TgM/KO mice were 52.6, 9.9, 29.6 and 44.4 unit/mg protein, respectively, corresponding to 16.4-, 0.8-, 0.6- and 1.4-fold of the endogenous enzyme activities in the same tissues of non-transgenic mice with a similar genetic background. Oral administration of 1-deoxygalactonojirimycin (DGJ), a competitive inhibitor of alpha-Gal A and an effective ASSC for Fabry disease, at 0.05 mM in the drinking water of the mice for 2 weeks resulted in 13.8-, 3.3-, 3.9-, and 2.6-fold increases in enzyme activities in the heart, kidney, spleen and liver, respectively. No accumulation of globotriaosylceramide, a natural substrate of alpha-Gal A, could be detected in the heart of TgM/KO mice after DGJ treatment, indicating that degradation of the glycolipid in the heart was not inhibited by DGJ at that dosage. The alpha-Gal A activity in homozygous or heterozygous fibroblasts established from TgM/KO mice (TMK cells) was approximately 39 and 20 unit/mg protein, respectively. These TgM/KO mice and TMK cells are useful tools for studying the mechanism of ASSC therapy, and for screening ASSCs for Fabry disease.
authors.affiliation: Department of Human Genetics, Mount Sinai School of Medicine, Fifth Avenue at 100th Street, New York, NY 10029, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishii
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Yoshioka
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Mannen
authors.forename: Ashok B
authors.initials: AB
authors.lastname: Kulkarni
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Fan
mesh_terms: D017485:1-Deoxynojirimycin / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D004195:Disease Models, Animal; D000795:Fabry Disease / Q000201:enzymology / Q000235:genetics / Q000628:therapy*; D005347:Fibroblasts; D015316:Genetic Therapy; D006321:Heart / Q000187:drug effects; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D009206:Myocardium / Q000378:metabolism; D017510:Protein Folding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012680:Sensitivity and Specificity; D014281:Trihexosylceramides / Q000378:metabolism; D000519:alpha-Galactosidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018832:Molecular Chaperones; D012333:RNA, Messenger; D014281:Trihexosylceramides; D017485:1-Deoxynojirimycin; C018549:globotriaosylceramide; D000519:alpha-Galactosidase