title: A decrease in hepatic microRNA-9 expression impairs gluconeogenesis by targeting FOXO1 in obese mice.
abstract: MicroRNA-9 (miR-9) is involved in the regulation of pancreatic beta cell function. However, its role in gluconeogenesis is still unclear. Our objective was to investigate the role of miR-9 in hepatic glucose production (HGP).
  
  
  
  MiR-9 expression was measured in livers of high-fat diet (HFD) mice and ob/ob mice. The methylation status of the miR-9-3 promoter regions in hepatocytes was determined by the methylation-specific PCR procedure. The binding activity of DNA methyltransferase (DNMT)1, DNMT3a and DNMT3b on the miR-9-3 promoter was detected by chromatin immunoprecipitation (ChIP) and quantitative real-time PCR assays. HGP was evaluated in vitro and in vivo. Glucose tolerance, insulin tolerance and pyruvate tolerance tests were also performed.
  
  
  
  Reduced miR-9 expression and hypermethylation of the miR-9-3 promoter were observed in the livers of obese mice. Further study showed that the binding of DNMT1, but not of DNMT3a and DNMT3b, to the miR-9-3 promoter was increased in hepatocytes from ob/ob mice. Knockdown of DNMT1 alleviated the decrease in hepatic miR-9 expression in vivo and in vitro. Overexpression of hepatic miR-9 improved insulin sensitivity in obese mice and inhibited HGP. In addition, deletion of hepatic miR-9 led to an increase in random and fasting blood glucose levels in lean mice. Importantly, silenced forkhead box O1 (FOXO1) expression reversed the gluconeogenesis and glucose production in hepatocytes induced by miR-9 deletion.
  
  
  
  Our observations suggest that the decrease in miR-9 expression contributes to an inappropriately activated gluconeogenesis in obese mice.
authors.affiliation: Department of Endocrinology, Clinical Medical College of Yangzhou University, Yangzhou, China.|Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
authors.forename: Caifeng
authors.initials: C
authors.lastname: Yan
authors.affiliation: Department of Endocrinology, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.affiliation: Center of Pathology and Clinical Laboratory, Mingde Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Xuan
authors.affiliation: Center of Pathology and Clinical Laboratory, Mingde Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Dongming
authors.initials: D
authors.lastname: Su
authors.affiliation: Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
authors.forename: Hui
authors.initials: H
authors.lastname: You
authors.affiliation: Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Endocrinology, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, China.
authors.forename: Nuoqi
authors.initials: N
authors.lastname: Chen
authors.affiliation: Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China. liangxiubin@njmu.edu.cn.
authors.forename: Xiubin
authors.initials: X
authors.lastname: Liang
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics / Q000502:physiology; D000090205:DNA Methyltransferase 3A; D059305:Diet, High-Fat; D000071161:Forkhead Box Protein O1 / Q000235:genetics / Q000378:metabolism*; D005943:Gluconeogenesis / Q000235:genetics / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D051379:Mice; D008820:Mice, Obese; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D000097584:DNA Methyltransferase 3B
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D000071161:Forkhead Box Protein O1; D005947:Glucose; D035683:MicroRNAs; D000097584:DNA Methyltransferase 3B; C000715535:Dnmt3a protein, mouse; C467200:Foxo1 protein, mouse; C551804:MIRN9 microRNA, mouse
keywords: DNA methylation; FOXO1; Insulin resistance; MicroRNA-9