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

Latouche C, Natoli A, Reddy-Luthmoodoo M, Heywood SE, Armitage JA, Kingwell BA - PLoS ONE (2016)

Bottom Line: Twenty-three miRNAs were differentially expressed in patients with T2DM, and 7 in the insulin resistant rat offspring compared to their controls.Moreover, oxidative capacity was also increased as we found an enhanced glucose oxidation in presence of the mitochondrial uncoupler FCCP.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.

View Article: PubMed Central - PubMed

Affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.

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.

No MeSH data available.


Related in: MedlinePlus

Effect of miR-194 inhibition on AKT and GSK3β expression in L6 cells.Expression of the phosphorylated and total forms of AKT (A) and GSK3β (B) were measured by Western blot in L6 cells 48 hours after transfection with a miR-194 inhibitor. Ratios phosphorylated:total are expressed as mean ± SEM (n = 3 per group). Representative blots are shown below the graphs. P-values were determined using 2-way ANOVA (normally distributed data) or Kruskal-Wallis 1-way ANOVA on ranks (non-normally distributed data) followed by Student-Newman-Keuls post-hoc tests (* p<0.05 vs. control, # p<0.05 vs. basal).
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pone.0155108.g004: Effect of miR-194 inhibition on AKT and GSK3β expression in L6 cells.Expression of the phosphorylated and total forms of AKT (A) and GSK3β (B) were measured by Western blot in L6 cells 48 hours after transfection with a miR-194 inhibitor. Ratios phosphorylated:total are expressed as mean ± SEM (n = 3 per group). Representative blots are shown below the graphs. P-values were determined using 2-way ANOVA (normally distributed data) or Kruskal-Wallis 1-way ANOVA on ranks (non-normally distributed data) followed by Student-Newman-Keuls post-hoc tests (* p<0.05 vs. control, # p<0.05 vs. basal).

Mentions: To address the possible mechanisms by which miR-194 regulates glucose metabolism, we examined components of signaling pathways contributing to glucose metabolism. Phosphorylation of AKT (Ser473) and GSK3β (Ser9), relative to total expression, in response to insulin were increased by 43±9% and 71±4% respectively (p<0.05) in L6 cells transfected with the miR-194 inhibitor (Fig 4). There was no effect on phosphorylation of these proteins by miR-194 inhibition under basal conditions.


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

Latouche C, Natoli A, Reddy-Luthmoodoo M, Heywood SE, Armitage JA, Kingwell BA - PLoS ONE (2016)

Effect of miR-194 inhibition on AKT and GSK3β expression in L6 cells.Expression of the phosphorylated and total forms of AKT (A) and GSK3β (B) were measured by Western blot in L6 cells 48 hours after transfection with a miR-194 inhibitor. Ratios phosphorylated:total are expressed as mean ± SEM (n = 3 per group). Representative blots are shown below the graphs. P-values were determined using 2-way ANOVA (normally distributed data) or Kruskal-Wallis 1-way ANOVA on ranks (non-normally distributed data) followed by Student-Newman-Keuls post-hoc tests (* p<0.05 vs. control, # p<0.05 vs. basal).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862646&req=5

pone.0155108.g004: Effect of miR-194 inhibition on AKT and GSK3β expression in L6 cells.Expression of the phosphorylated and total forms of AKT (A) and GSK3β (B) were measured by Western blot in L6 cells 48 hours after transfection with a miR-194 inhibitor. Ratios phosphorylated:total are expressed as mean ± SEM (n = 3 per group). Representative blots are shown below the graphs. P-values were determined using 2-way ANOVA (normally distributed data) or Kruskal-Wallis 1-way ANOVA on ranks (non-normally distributed data) followed by Student-Newman-Keuls post-hoc tests (* p<0.05 vs. control, # p<0.05 vs. basal).
Mentions: To address the possible mechanisms by which miR-194 regulates glucose metabolism, we examined components of signaling pathways contributing to glucose metabolism. Phosphorylation of AKT (Ser473) and GSK3β (Ser9), relative to total expression, in response to insulin were increased by 43±9% and 71±4% respectively (p<0.05) in L6 cells transfected with the miR-194 inhibitor (Fig 4). There was no effect on phosphorylation of these proteins by miR-194 inhibition under basal conditions.

Bottom Line: Twenty-three miRNAs were differentially expressed in patients with T2DM, and 7 in the insulin resistant rat offspring compared to their controls.Moreover, oxidative capacity was also increased as we found an enhanced glucose oxidation in presence of the mitochondrial uncoupler FCCP.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.

View Article: PubMed Central - PubMed

Affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.

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.

No MeSH data available.


Related in: MedlinePlus