A decrease in hepatic microRNA-9 expression impairs gluconeogenesis by targeting FOXO1 in obese mice

Abstract

Aim/hypothesis 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). Methods 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. Results 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. Conclusions/interpretation Our observations suggest that the decrease in miR-9 expression contributes to an inappropriately activated gluconeogenesis in obese mice.

Long noncoding RNA Gomafu upregulates Foxo1 expression to promote hepatic insulin resistance by sponging miR-139-5p

“…Hepatocytes were isolated and cultured from the livers of male C57BL/BKS mice as described previously 10 . Cell viability of primary hepatocytes was evaluated by the trypan blue exclusion test and was always higher than 70%.…”

“…Recent studies have shown that microRNAs are involved in regulating hepatic Foxo1 expression and activity. Our previous study demonstrated that miR-9 was a regulator in hepatic gluconeogenesis and HPG by directly targeting Foxo1 both in vitro and in vivo 10 . Luo et al confirmed that miR-21 regulated hepatic gluconeogenesis and insulin sensitivity through Foxo1 and its down signaling pathways 11 .…”

α-Tocopherol influences glycaemic control and miR-9-3 DNA methylation in overweight and obese women under an energy-restricted diet: a randomized, double-blind, exploratory, controlled clinical trial

“…Transcription of miRs can also be epigenetically regulated by methylation in CpG islands [ 12 , 13 ]. In the human genome, there are three different regions that can be transcribed in the same mature miR-9 sequence: miR-9-1 (chromosome 1), miR-9-2 (chromosome 5) and miR-9-3 (chromosome 15) [ 10 , 14 ]. MiR-9 plays a role in insulin and glucose homeostasis, in vitro and in vivo, and its dysregulation has been associated with obesity, diabetes, and non-alcoholic fatty liver disease [ 14 – 17 ].…”

“…In the human genome, there are three different regions that can be transcribed in the same mature miR-9 sequence: miR-9-1 (chromosome 1), miR-9-2 (chromosome 5) and miR-9-3 (chromosome 15) [ 10 , 14 ]. MiR-9 plays a role in insulin and glucose homeostasis, in vitro and in vivo, and its dysregulation has been associated with obesity, diabetes, and non-alcoholic fatty liver disease [ 14 – 17 ]. However, despite these findings, the impact of nutritional interventions related to obesity on miR methylation levels has not yet been described, with most studies investigating genes encoding mRNA [ 4 ].…”

Micromanaging Freeze Tolerance: The Biogenesis and Regulation of microRNAs in Frozen Frogs

“…4.2). This is likely being facilitated by FOXO1, as studies have shown that decreased levels of hepatic miR-9 expression activate gluconeogenesis and promote hepatic glucose production via a FOXO1-mechanism (Yan et al, 2016). Taken together, these newlyidentified hepatic miRNA modulation mechanisms help prevent the breakdown of valuable glucose cryoprotective stores and add an additional layer of regulatory complexity to the biochemical controls that are known to directly modulate these metabolic enzymes.…”