Lack of glucose recycling between endoplasmic reticulum and cytoplasm underlies cellular dysfunction in glucose-6-phosphatase-β–deficient neutrophils in a congenital neutropenia syndrome

• Published in: Blood 2010-10, Vol.116 (15), p.2783-2792
• Main Authors: Jun, Hyun Sik, Lee, Young Mok, Cheung, Yuk Yin, McDermott, David H., Murphy, Philip M., De Ravin, Suk See, Mansfield, Brian C., Chou, Janice Y.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Adolescent; Animals; Annexin A5 - metabolism; Apoptosis; Biological and medical sciences; Caspase 3 - metabolism; Child; Cytoplasm - metabolism; Endoplasmic Reticulum - metabolism; Female; Glucose - metabolism; Glucose Transporter Type 1 - metabolism; Glucose-6-Phosphatase - genetics; Glucose-6-Phosphatase - metabolism; Glycogen Storage Disease Type I - genetics; Glycogen Storage Disease Type I - metabolism; Glycogen Storage Disease Type I - pathology; Hematologic and hematopoietic diseases; Humans; Lactic Acid - metabolism; Male; Medical sciences; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH Oxidases - metabolism; Neutropenia - congenital; Neutropenia - genetics; Neutropenia - metabolism; Neutropenia - pathology; Neutrophils - metabolism; Neutrophils - pathology; Phagocytes, Granulocytes, and Myelopoiesis; Stress, Physiological; Syndrome
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2009-12-258491

G6PC3 deficiency, characterized by neutropenia and neutrophil dysfunction, is caused by deficiencies in the endoplasmic reticulum (ER) enzyme glucose-6-phosphatase-β (G6Pase-β or G6PC3) that converts glucose-6-phosphate (G6P) into glucose, the primary energy source of neutrophils. Enhanced neutrophil ER stress and apoptosis underlie neutropenia in G6PC3 deficiency, but the exact functional role of G6Pase-β in neutrophils remains unknown. We hypothesized that the ER recycles G6Pase-β–generated glucose to the cytoplasm, thus regulating the amount of available cytoplasmic glucose/G6P in neutrophils. Accordingly, a G6Pase-β deficiency would impair glycolysis and hexose monophosphate shunt activities leading to reductions in lactate production, adenosine-5′-triphosphate (ATP) production, and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. Using annexin V–depleted neutrophils, we show that glucose transporter-1 translocation is impaired in neutrophils from G6pc3−/− mice and G6PC3-deficient patients along with impaired glucose uptake in G6pc3−/− neutrophils. Moreover, levels of G6P, lactate, and ATP are markedly lower in murine and human G6PC3-deficient neutrophils, compared with their respective controls. In parallel, the expression of NADPH oxidase subunits and membrane translocation of p47phox are down-regulated in murine and human G6PC3-deficient neutrophils. The results establish that in nonapoptotic neutrophils, G6Pase-β is essential for normal energy homeostasis. A G6Pase-β deficiency prevents recycling of ER glucose to the cytoplasm, leading to neutrophil dysfunction.