title: The upstream enhancer elements of the G6PC promoter are critical for optimal G6PC expression in murine glycogen storage disease type Ia.
abstract: Glycogen storage disease type-Ia (GSD-Ia) patients deficient in glucose-6-phosphatase-α (G6Pase-α or G6PC) manifest impaired glucose homeostasis characterized by fasting hypoglycemia, growth retardation, hepatomegaly, nephromegaly, hyperlipidemia, hyperuricemia, and lactic acidemia. Two efficacious recombinant adeno-associated virus pseudotype 2/8 (rAAV8) vectors expressing human G6Pase-α have been independently developed. One is a single-stranded vector containing a 2864-bp of the G6PC promoter/enhancer (rAAV8-GPE) and the other is a double-stranded vector containing a shorter 382-bp minimal G6PC promoter/enhancer (rAAV8-miGPE). To identify the best construct, a direct comparison of the rAAV8-GPE and the rAAV8-miGPE vectors was initiated to determine the best vector to take forward into clinical trials. We show that the rAAV8-GPE vector directed significantly higher levels of hepatic G6Pase-α expression, achieved greater reduction in hepatic glycogen accumulation, and led to a better toleration of fasting in GSD-Ia mice than the rAAV8-miGPE vector. Our results indicated that additional control elements in the rAAV8-GPE vector outweigh the gains from the double-stranded rAAV8-miGPE transduction efficiency, and that the rAAV8-GPE vector is the current choice for clinical translation in human GSD-Ia.
authors.affiliation: Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Young Mok
authors.initials: YM
authors.lastname: Lee
authors.forename: Chi-Jiunn
authors.initials: CJ
authors.lastname: Pan
authors.forename: Dwight D
authors.initials: DD
authors.lastname: Koeberl
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; D004195:Disease Models, Animal; D004742:Enhancer Elements, Genetic; D015870:Gene Expression; D005786:Gene Expression Regulation; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D005952:Glucose-6-Phosphatase / Q000235:genetics*; D005953:Glycogen Storage Disease Type I / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism; D055442:Metabolome; D051379:Mice; D018345:Mice, Knockout; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D014161:Transduction, Genetic; D019076:Transgenes
chemical_list: D005952:Glucose-6-Phosphatase; D005947:Glucose
keywords: AAV; Adeno-associated virus; G6P; G6PC promoter/enhancer; G6Pase; GPE; GSD-Ia; Gene therapy; Glucose-6-phosphatase; Glycogen storage disease type I; HCA; adeno-associated virus; glucose-6-phosphatase; glucose-6-phosphate; glycogen storage disease type Ia; hepatocellular adenoma