title: Inhibition of silent information regulator 1 induces glucose metabolism disorders of hepatocytes and enhances hepatitis C virus replication.
abstract: OBJECTIVE
  Glucose metabolism disorders including insulin resistance (IR) and type 2 diabetes are frequent and important cofactors of chronic hepatitis C (CHC). Silent information regulator 1 (SIRT1) plays a key role in the regulation of hepatic glucose metabolism. We investigated the possible effect of HCV replication on glucose metabolism of hepatocytes and expression of SIRT1 using Huh-7.5 cells harboring the HCV replicon.
  
  
  METHODS
  The level of reactive oxygen species (ROS) and value of NAD(+)/NADH and ATP/ADP were detected. Glucose uptake by hepatocytes and glucose production were measured. The activity and expression levels of SIRT1 and expression of its downstream glucose-metabolism genes were measured.
  
  
  RESULTS
  In replicon cells, the level of ROS increased and the value of nicotinamide adenine dinucleotide (NAD(+))/NADH decreased, then the activity and expression level of mRNA and protein of SIRT1 decreased. Inhibition of SIRT1 not only increased insulin receptor substrate-1 phosphorylation and decreased Akt phosphorylation, inhibited cell surface expression of glucose transporter 2 and suppressed cellular glucose uptake, but it also decreased phosphorylation of forkhead box O1, then upregulated phosphoenolpyruvate carboxykinase and glucose 6-phosphatase genes and downregulated the glucokinase gene, thus promoting glucose production. Interferon treatment restored the aforementioned changes. SIRT1 activator improved glucose metabolism disorders by an increase in glucose uptake and a decrease in glucose production, and it inhibited HCV replication.
  
  
  CONCLUSIONS
  HCV replication decreasing the NAD(+)/NADH ratio may downregulate the activity and expression of SIRT1, then change the expression profile of glucose metabolism-related genes, thereby causing glucose metabolism disorders of hepatocytes and promoting HCV replication. Treatment with SIRT1 activator improves glucose metabolic disorders and inhibits HCV replication, suggesting that restoration of SIRT1 activity may be a promising new therapeutic approach for CHC patients with IR.
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Harbin Medical University, 246 Xuefu Road, Nangang District, Harbin, 150086, China.
authors.forename: Jian-Wu
authors.initials: JW
authors.lastname: Yu
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Harbin Medical University, 246 Xuefu Road, Nangang District, Harbin, 150086, China. lijiesun5234@yahoo.com.cn.
authors.forename: Li-Jie
authors.initials: LJ
authors.lastname: Sun
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Harbin Medical University, 246 Xuefu Road, Nangang District, Harbin, 150086, China.
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Zhao
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Harbin Medical University, 246 Xuefu Road, Nangang District, Harbin, 150086, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Kang
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Harbin Medical University, 246 Xuefu Road, Nangang District, Harbin, 150086, China.
authors.forename: Bing-Zhu
authors.initials: BZ
authors.lastname: Yan
keywords: Hepatic glucose metabolism; Hepatitis C viruses; Silent information regulator 1 (SIRT1)