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MiR-19a regulates PTEN expression to mediate glycogen synthesis in hepatocytes.

Dou L, Meng X, Sui X, Wang S, Shen T, Huang X, Guo J, Fang W, Man Y, Xi J, Li J - Sci Rep (2015)

Bottom Line: We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis.Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes.Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China.

ABSTRACT
MiR-19a, a member of mir-17-92 microRNA clusters, has been demonstrated to promote cell proliferation and angiogenesis via regulating the PI3K/AKT pathway, the major insulin signaling pathway. However, whether miR-19a plays an important role in glycogen synthesis in hepatocytes remains unknown. Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms. Our studies indicate that miR-19a was down-regulated in the livers of db/db mice and mice injected with IL-6, as well as mouse NCTC 1469 hepatocytes and HEP 1-6 hepatocytes treated by IL-6. We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis. Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes. Moreover, we identified PTEN as the target of miR-19a by a luciferase assay. Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells. These findings show for the first time that miR-19a might activate the AKT/GSK pathway and glycogenesis via down-regulation of PTEN expression.

No MeSH data available.


Related in: MedlinePlus

MiR-19a ameliorates IL-6-induced impaired phosphorylation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.Activation of the AKT/GSK pathway (a and b) and synthesis of glycogen (e and f) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics for 48 h. AKT/GSK pathway activation (c and d) and glycogenesis (g and h) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a inhibitor for 48 h. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs.IL-6). Full-length blots are presented in the supplementary information (supplementary Figure S3).
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f3: MiR-19a ameliorates IL-6-induced impaired phosphorylation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.Activation of the AKT/GSK pathway (a and b) and synthesis of glycogen (e and f) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics for 48 h. AKT/GSK pathway activation (c and d) and glycogenesis (g and h) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a inhibitor for 48 h. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs.IL-6). Full-length blots are presented in the supplementary information (supplementary Figure S3).

Mentions: To further determine the role of miR-19a in IL-6-induced insulin resistance, NCTC 1469 cells and HEP 1–6 cells were treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics or inhibitor for 48 h. Over-expression of miR-19a ameliorated IL-6-induced impaired activation of the AKT/GSK pathway (Fig. 3a,b) and synthesis of glycogen (Fig. 3e,f) in NCTC 1469 cells and HEP 1–6 cells. However, down-regulation of miR-19a further promoted IL-6-induced reduced AKT/GSK pathway activation (Fig. 3c,d) and glycogenesis (Fig. 3g,h) in NCTC 1469 cells and HEP 1–6 cells.


MiR-19a regulates PTEN expression to mediate glycogen synthesis in hepatocytes.

Dou L, Meng X, Sui X, Wang S, Shen T, Huang X, Guo J, Fang W, Man Y, Xi J, Li J - Sci Rep (2015)

MiR-19a ameliorates IL-6-induced impaired phosphorylation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.Activation of the AKT/GSK pathway (a and b) and synthesis of glycogen (e and f) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics for 48 h. AKT/GSK pathway activation (c and d) and glycogenesis (g and h) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a inhibitor for 48 h. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs.IL-6). Full-length blots are presented in the supplementary information (supplementary Figure S3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481380&req=5

f3: MiR-19a ameliorates IL-6-induced impaired phosphorylation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.Activation of the AKT/GSK pathway (a and b) and synthesis of glycogen (e and f) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics for 48 h. AKT/GSK pathway activation (c and d) and glycogenesis (g and h) in the NCTC 1469 cells and HEP 1–6 cells treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a inhibitor for 48 h. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs.IL-6). Full-length blots are presented in the supplementary information (supplementary Figure S3).
Mentions: To further determine the role of miR-19a in IL-6-induced insulin resistance, NCTC 1469 cells and HEP 1–6 cells were treated with 10 ng/ml IL-6 for 24 h followed by transfection with miR-19a mimics or inhibitor for 48 h. Over-expression of miR-19a ameliorated IL-6-induced impaired activation of the AKT/GSK pathway (Fig. 3a,b) and synthesis of glycogen (Fig. 3e,f) in NCTC 1469 cells and HEP 1–6 cells. However, down-regulation of miR-19a further promoted IL-6-induced reduced AKT/GSK pathway activation (Fig. 3c,d) and glycogenesis (Fig. 3g,h) in NCTC 1469 cells and HEP 1–6 cells.

Bottom Line: We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis.Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes.Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China.

ABSTRACT
MiR-19a, a member of mir-17-92 microRNA clusters, has been demonstrated to promote cell proliferation and angiogenesis via regulating the PI3K/AKT pathway, the major insulin signaling pathway. However, whether miR-19a plays an important role in glycogen synthesis in hepatocytes remains unknown. Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms. Our studies indicate that miR-19a was down-regulated in the livers of db/db mice and mice injected with IL-6, as well as mouse NCTC 1469 hepatocytes and HEP 1-6 hepatocytes treated by IL-6. We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis. Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes. Moreover, we identified PTEN as the target of miR-19a by a luciferase assay. Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells. These findings show for the first time that miR-19a might activate the AKT/GSK pathway and glycogenesis via down-regulation of PTEN expression.

No MeSH data available.


Related in: MedlinePlus