Aberrant proliferation and differentiation of glycogen storage disease type Ib mesenchymal stem cells.

Glycogen storage disease type Ib (GSD-Ib) is caused by mutations of the glucose-6-phosphate transporter (G6PT) and characterized by disrupted glucose homeostasis, neutropenia, and neutrophil dysfunction. To investigate the role of G6PT in human adipose-derived mesenchymal stem cells (hMSCs), the G6PT gene was mutated by CRISPR/Cas9 technology and single cell-derived G6PT-/- hMSCs were established. G6PT-/- hMSCs have significantly increased cell proliferation but impaired adipogenesis and osteogenesis. These phenotypes are associated with two mechanisms: i) metabolic reprogramming in G6PT-/- hMSCs causing a metabolic shift toward glycolysis rather than oxidative phosphorylation and ii) increased cyclooxygenase-2-derived prostaglandin E2 secretion in G6PT-/- hMSCs. This study demonstrates that G6PT is essential for proliferation and differentiation of MSCs, providing important insights into the GSD-Ib phenotypes.