title: Differential expression of genes and changes in glucose metabolism in the liver of liver-specific glucokinase gene knockout mice.
abstract: To investigate the role of liver-specific expression of glucokinase (GCK) in the pathogenesis of hyperglycemia and to identify candidate genes involved in mechanisms of the onset and progression of maturity onset diabetes of the young, type 2 (MODY-2), we examined changes in biochemical parameters and gene expression in GCK knockout (gck(w/-)) and wild-type (gck(w/w)) mice as they aged. Fasting blood glucose levels were found to be significantly higher in the gck(w/-) mice, compared to age-matched gck(w/w) mice, at all ages (P<0.05), except at 2 weeks. GCK activity of gck(w/-) mice was about 50% of that of wild type (gck(w/w)) mice (P<0.05). Glycogen content at 4 and 40 weeks of age was lower in gck(w/-) mice compared to gck(w/w) mice. Differentially expressed genes in the livers of 2 and 26 week-old liver-specific GCK knockout (gck(w/-)) mice were identified by suppression subtractive hybridization (SSH), which resulted in the identification of phosphoenolpyruvatecarboxykinase (PEPCK, also called PCK1) and Sterol O-acyltransferase 2 (SOAT2) as candidate genes involved in pathogenesis. The expressions of PEPCK and SOAT2 along with glycogen phosphorylase (GP) and glycogen synthase (GS) were then examined in GCK knockout (gck(w/-)) and wild-type (gck(w/w)) mice at different ages. Changes in PEPCK mRNA levels were confirmed by real-time RT-PCR, while no differences in the levels of expression of SOAT2 or GS were observed in age-matched GCK knockout (gck(w/-)) and wild-type (gck(w/w)) mice. GP mRNA levels were decreased in 40-week old gck(w/-) mice compared to age-matched gck(w/w) mice. Changes in gluconeogenesis, delayed development of GCK and impaired hepatic glycogen synthesis in the liver potentially lead to the onset and progression of MODY2.
authors.affiliation: Department of Pharmacology, Peking University, Health Science Center, Beijing 100191, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Yiqing
authors.initials: Y
authors.lastname: Mao
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Tingting
authors.initials: T
authors.lastname: Guo
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.forename: Rongjing
authors.initials: R
authors.lastname: Song
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Li
authors.forename: David M
authors.initials: DM
authors.lastname: Irwin
authors.forename: Gang
authors.initials: G
authors.lastname: Niu
authors.forename: Huanran
authors.initials: H
authors.lastname: Tan
mesh_terms: D000367:Age Factors; D000818:Animals; D050260:Carbohydrate Metabolism / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D018450:Disease Progression; D005786:Gene Expression Regulation; D005941:Glucokinase / Q000235:genetics* / Q000378:metabolism; D005943:Gluconeogenesis / Q000235:genetics / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009928:Organ Specificity / Q000235:genetics; D059467:Transcriptome
chemical_list: D005941:Glucokinase; D005947:Glucose