Development and characterization of an inducible mouse model for glycogen storage disease type Ib
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Background and aims
Glycogen storage disease type Ib (GSD1b) is a rare metabolic and immune disorder caused by a deficiency in the glucose-6-phosphate transporter (G6PT) and characterized by impaired glucose homeostasis, myeloid dysfunction, and long-term risk of hepatocellular adenomas. Despite maximal therapy, based on a strict diet and on granulocyte colony-stimulating factor treatment, long-term severe complications still develop. Understanding the pathophysiology of GSD1b is a prerequisite to develop new therapeutic strategies and depends on the availability of animal models. The G6PT-KO mouse mimics the human disease but is very fragile and rarely survives weaning. We generated a conditional G6PT-deficient mouse as an alternative model for studying the long-term pathophysiology of the disease. We utilized this conditional mouse to develop an inducible G6PT-KO model to allow temporally regulated G6PT deletion by the administration of tamoxifen (TM).
We generated a conditional G6PT-deficient mouse utilizing the CRElox strategy. Histology, histochemistry, and phenotype analyses were performed at different times after TM-induced G6PT inactivation. Neutrophils and monocytes were isolated and analyzed for functional activity with standard techniques.
The G6PT-inducible KO mice display the expected disturbances of G6P metabolism and myeloid dysfunctions of the human disorder, even though with a milder intensity.
TM-induced inactivation of G6PT in these mice leads to a phenotype which mimics that of human GSD1b patients. The conditional mice we have generated represent an excellent tool to study the tissue-specific role of the G6PT gene and the mechanism of long-term complications in GSD1b.
Compliance with ethical standards
Conflict of interest
Federica Raggi, Anna Livia Pissavino, Roberta Resaz, Daniela Segalerba, Andrea Puglisi, Cristina Vanni, Francesca Antonini, Genny Del Zotto, Alessandra Gamberucci, Paola Marcolongo, Maria Carla Bosco, Federica Grillo, Luca Mastracci, and Alessandra Eva declare that they have no conflict of interest.
This work was supported by grants from Associazione Italiana Glicogenosi (to A.E.), from Compagnia di San Paolo (grant 318 to A.E.), and Ministero della Salute.
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