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Minimal hepatic glucose-6-phosphatase-α activity required to sustain survival and prevent hepatocellular adenoma formation in murine glycogen storage disease type Ia

Glycogen storage disease type Ia (GSD-Ia), characterized by impaired glucose homeostasis and chronic risk of hepatocellular adenoma (HCA), is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC) activity. In a previous 70–90 week-study, we showed that a recombinant adeno-associated v...

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Detalles Bibliográficos
Autores principales: Lee, Young Mok, Kim, Goo-Young, Pan, Chi-Jiunn, Mansfield, Brian C., Chou, Janice Y.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4750588/
https://www.ncbi.nlm.nih.gov/pubmed/26937391
http://dx.doi.org/10.1016/j.ymgmr.2015.03.001
Descripción
Sumario:Glycogen storage disease type Ia (GSD-Ia), characterized by impaired glucose homeostasis and chronic risk of hepatocellular adenoma (HCA), is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC) activity. In a previous 70–90 week-study, we showed that a recombinant adeno-associated virus (rAAV) vector-mediated gene transfer that restores more than 3% of wild-type hepatic G6Pase-α activity in G6pc(−/−) mice corrects hepatic G6Pase-α deficiency with no evidence of HCA. We now examine the minimal hepatic G6Pase-α activity required to confer therapeutic efficacy. We show that rAAV-treated G6pc(−/−) mice expressing 0.2% of wild-type hepatic G6Pase-α activity suffered from frequent hypoglycemic seizures at age 63–65 weeks but mice expressing 0.5–1.3% of wild-type hepatic G6Pase-α activity (AAV-LL mice) sustain 4–6 h of fast and grow normally to age 75–90 weeks. Despite marked increases in hepatic glycogen accumulation, the AAV-LL mice display no evidence of hepatic abnormalities, hepatic steatosis, or HCA. Interprandial glucose homeostasis is maintained by the G6Pase-α/glucose-6-phosphate transporter (G6PT) complex, and G6PT-mediated microsomal G6P uptake is the rate-limiting step in endogenous glucose production. We show that hepatic G6PT activity is increased in AAV-LL mice. These findings are encouraging for clinical studies of G6Pase-α gene-based therapy for GSD-Ia.