title: Complete normalization of hepatic G6PC deficiency in murine glycogen storage disease type Ia using gene therapy.
abstract: Glycogen storage disease type Ia (GSD-Ia) patients deficient in glucose-6-phosphatase-alpha (G6Pase-alpha or G6PC) manifest disturbed glucose homeostasis. We examined the efficacy of liver G6Pase-alpha delivery mediated by AAV-GPE, an adeno-associated virus (AAV) serotype 8 vector expressing human G6Pase-alpha directed by the human G6PC promoter/enhancer (GPE), and compared it to AAV-CBA, that directed murine G6Pase-alpha expression using a hybrid chicken beta-actin (CBA) promoter/cytomegalovirus (CMV) enhancer. The AAV-GPE directed hepatic G6Pase-alpha expression in the infused G6pc(-/-) mice declined 12-fold from age 2 to 6 weeks but stabilized at wild-type levels from age 6 to 24 weeks. In contrast, the expression directed by AAV-CBA declined 95-fold over 24 weeks, demonstrating that the GPE is more effective in directing persistent in vivo hepatic transgene expression. We further show that the rapid decline in transgene expression directed by AAV-CBA results from an inflammatory immune response elicited by the AAV-CBA vector. The AAV-GPE-treated G6pc(-/-) mice exhibit normal levels of blood glucose, blood metabolites, hepatic glycogen, and hepatic fat. Moreover, the mice maintained normal blood glucose levels even after 6 hours of fasting. The complete normalization of hepatic G6Pase-alpha deficiency by the G6PC promoter/enhancer holds promise for the future of gene therapy in human GSD-Ia patients.
authors.affiliation: Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1830, USA.
authors.forename: Wai Han
authors.initials: WH
authors.lastname: Yiu
authors.forename: Young Mok
authors.initials: YM
authors.lastname: Lee
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Peng
authors.forename: Chi-Jiunn
authors.initials: CJ
authors.lastname: Pan
authors.forename: Paul A
authors.initials: PA
authors.lastname: Mead
authors.forename: Brian C
authors.initials: BC
authors.lastname: Mansfield
authors.forename: Janice Y
authors.initials: JY
authors.lastname: Chou
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics; D015316:Genetic Therapy; D005822:Genetic Vectors; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics; D005953:Glycogen Storage Disease Type I / Q000628:therapy*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout
chemical_list: D005954:Glucosephosphate Dehydrogenase
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