Impaired neutrophil activity and increased susceptibility to bacterial infection in mice lacking glucose-6-phosphatase-beta

• Published in: The Journal of clinical investigation Vol. 117; no. 3; pp. 784 - 793
• Main Authors: Cheung, Yuk Yin, Kim, So Youn, Yiu, Wai Han, Pan, Chi-Jiunn, Jun, Hyun-Sik, Ruef, Robert A, Lee, Eric J, Westphal, Heiner, Mansfield, Brian C, Chou, Janice Y
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.03.2007
• Subjects: Animals; Bacteria; Bacterial infections; Bacterial Infections - enzymology; Bacterial Infections - genetics; Bacterial Infections - immunology; Blood Glucose - analysis; Disease Models, Animal; Genetic Predisposition to Disease; Glucose-6-phosphatase; Glucose-6-Phosphatase - analysis; Glucose-6-Phosphatase - genetics; Glucose-6-Phosphatase - metabolism; Glucose-6-Phosphate - metabolism; Hematopoiesis - genetics; Homeostasis; Leucopenia; Mice; Neutropenia; Neutropenia - enzymology; Neutropenia - genetics; Neutrophils - enzymology; Neutrophils - immunology; Peritonitis - enzymology; Peritonitis - genetics; Peritonitis - microbiology; Protein Subunits - analysis; Protein Subunits - genetics; Protein Subunits - metabolism; Rats as laboratory animals
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/JCI30443

Neutropenia and neutrophil dysfunction are common in many diseases, although their etiology is often unclear. Previous views held that there was a single ER enzyme, glucose-6-phosphatase-alpha (G6Pase-alpha), whose activity--limited to the liver, kidney, and intestine--was solely responsible for the final stages of gluconeogenesis and glycogenolysis, in which glucose-6-phosphate (G6P) is hydrolyzed to glucose for release to the blood. Recently, we characterized a second G6Pase activity, that of G6Pase-beta (also known as G6PC), which is also capable of hydrolyzing G6P to glucose but is ubiquitously expressed and not implicated in interprandial blood glucose homeostasis. We now report that the absence of G6Pase-beta led to neutropenia; defects in neutrophil respiratory burst, chemotaxis, and calcium flux; and increased susceptibility to bacterial infection. Consistent with this, G6Pase-beta-deficient (G6pc3-/-) mice with experimental peritonitis exhibited increased expression of the glucose-regulated proteins upregulated during ER stress in their neutrophils and bone marrow, and the G6pc3-/- neutrophils exhibited an enhanced rate of apoptosis. Our results define a molecular pathway to neutropenia and neutrophil dysfunction of previously unknown etiology, providing a potential model for the treatment of these conditions.