MicroRNA-194 Modulates Glucose Metabolism and Its Skeletal Muscle Expression Is Reduced in Diabetes

PLoS One. 2016 May 10;11(5):e0155108. doi: 10.1371/journal.pone.0155108. eCollection 2016.

Abstract

Background: The regulation of microRNAs (miRNAs) at different stages of the progression of type 2 diabetes mellitus (T2DM) and their role in glucose homeostasis was investigated.

Methods: Microarrays were used to assess miRNA expression in skeletal muscle biopsies taken from healthy individuals and patients with pre-diabetes or T2DM, and insulin resistant offspring of rat dams fed a high fat diet during pregnancy.

Results: Twenty-three miRNAs were differentially expressed in patients with T2DM, and 7 in the insulin resistant rat offspring compared to their controls. Among these, only one miRNA was similarly regulated: miR-194 expression was significantly reduced by 25 to 50% in both the rat model and in human with pre-diabetes and established diabetes. Knockdown of miR-194 in L6 skeletal muscle cells induced an increase in basal and insulin-stimulated glucose uptake and glycogen synthesis. This occurred in conjunction with an increased glycolysis, indicated by elevated lactate production. Moreover, oxidative capacity was also increased as we found an enhanced glucose oxidation in presence of the mitochondrial uncoupler FCCP. When miR-194 was down-regulated in vitro, western blot analysis showed an increased phosphorylation of AKT and GSK3β in response to insulin, and an increase in expression of proteins controlling mitochondrial oxidative phosphorylation.

Conclusions: Type 2 diabetes mellitus is associated with regulation of several miRNAs in skeletal muscle. Interestingly, miR-194 was a unique miRNA that appeared regulated across different stages of the disease progression, from the early stages of insulin resistance to the development of T2DM. We have shown miR-194 is involved in multiple aspects of skeletal muscle glucose metabolism from uptake, through to glycolysis, glycogenesis and glucose oxidation, potentially via mechanisms involving AKT, GSK3 and oxidative phosphorylation. MiR-194 could be down-regulated in patients with early features of diabetes as an adaptive response to facilitate tissue glucose uptake and metabolism in the face of insulin resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Diabetes Mellitus, Type 2 / genetics*
  • Diabetes Mellitus, Type 2 / metabolism
  • Diabetes Mellitus, Type 2 / pathology
  • Diet, High-Fat / adverse effects
  • Disease Models, Animal
  • Female
  • Gene Expression Regulation
  • Glucose / metabolism*
  • Glycogen / metabolism
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism
  • Humans
  • Insulin / metabolism*
  • Insulin Resistance
  • Male
  • Mice, Inbred C57BL
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Mitochondria / metabolism
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / pathology
  • Myoblasts / metabolism
  • Myoblasts / pathology
  • Oxidative Phosphorylation
  • Prediabetic State / etiology
  • Prediabetic State / genetics*
  • Prediabetic State / metabolism
  • Prediabetic State / pathology
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction

Substances

  • Insulin
  • MIRN194 microRNA, human
  • MIRN194 microRNA, rat
  • MicroRNAs
  • Glycogen
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3
  • Glucose

Grants and funding

JAA acknowledges Fellowships from the Heart Foundation and Monash University. BAK is a Senior Principal Research Fellow of the National Health and Medical Research Council of Australia. This work was supported by the Heart Foundation G11M 5728 and an NHMRC Program Grant and the OIS scheme from the Victorian State Government. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.