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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: Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms.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.

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 mediates activation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.(a and g) Levels of miR-19a in mouse NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics or miRNA mimic control. Activation of the AKT/GSK pathway (b and h) and synthesis of glycogen (e and k) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics. (c and i) Expression of miR-19a in the NCTC 1469 cells transfected with miR-19a inhibitor or miRNA inhibitor control. Phosphorylation of the AKT/GSK pathway (d and j) and synthesis of glycogen (f and l) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a inhibitor. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01byANOVAtest (vs. control). Full-length blots are presented in the supplementary information (supplementary Figure S2).
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f2: MiR-19a mediates activation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.(a and g) Levels of miR-19a in mouse NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics or miRNA mimic control. Activation of the AKT/GSK pathway (b and h) and synthesis of glycogen (e and k) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics. (c and i) Expression of miR-19a in the NCTC 1469 cells transfected with miR-19a inhibitor or miRNA inhibitor control. Phosphorylation of the AKT/GSK pathway (d and j) and synthesis of glycogen (f and l) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a inhibitor. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01byANOVAtest (vs. control). Full-length blots are presented in the supplementary information (supplementary Figure S2).

Mentions: Next, we investigated the effects of miR-19a on the activation of the PI3K/AKT pathway and glycogenesis in NCTC 1469 cells and HEP 1–6 cells. MiR-19a mimics and inhibitor were transfected into both types of cells for 48 h. As shown in Fig. 2a and 2b, the level of miR-19a was increased to more than 100-fold in the two cell lines transfected with miR-19a mimics compared with those transfected with miRNA mimic control. In parallel with the increased miR-19a expression, the synthesis of glycogen and the activation of the AKT/glycogen synthase kinase (GSK) pathway were elevated in both NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics (Fig. 2c–f). In contrast, the level of miR-19a was decreased to 30-40% compared with those transfected with miRNA inhibitor control (Fig. 2g,h). Inhibition of miR-19a blocked glycogenesis (Fig. 2i,j) and the activation of the PI3K/AKT pathway (Fig. 2k,l).


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 mediates activation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.(a and g) Levels of miR-19a in mouse NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics or miRNA mimic control. Activation of the AKT/GSK pathway (b and h) and synthesis of glycogen (e and k) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics. (c and i) Expression of miR-19a in the NCTC 1469 cells transfected with miR-19a inhibitor or miRNA inhibitor control. Phosphorylation of the AKT/GSK pathway (d and j) and synthesis of glycogen (f and l) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a inhibitor. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01byANOVAtest (vs. control). Full-length blots are presented in the supplementary information (supplementary Figure S2).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: MiR-19a mediates activation of the AKT/GSK pathway and synthesis of glycogen in hepatocytes.(a and g) Levels of miR-19a in mouse NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics or miRNA mimic control. Activation of the AKT/GSK pathway (b and h) and synthesis of glycogen (e and k) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics. (c and i) Expression of miR-19a in the NCTC 1469 cells transfected with miR-19a inhibitor or miRNA inhibitor control. Phosphorylation of the AKT/GSK pathway (d and j) and synthesis of glycogen (f and l) in the NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a inhibitor. Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01byANOVAtest (vs. control). Full-length blots are presented in the supplementary information (supplementary Figure S2).
Mentions: Next, we investigated the effects of miR-19a on the activation of the PI3K/AKT pathway and glycogenesis in NCTC 1469 cells and HEP 1–6 cells. MiR-19a mimics and inhibitor were transfected into both types of cells for 48 h. As shown in Fig. 2a and 2b, the level of miR-19a was increased to more than 100-fold in the two cell lines transfected with miR-19a mimics compared with those transfected with miRNA mimic control. In parallel with the increased miR-19a expression, the synthesis of glycogen and the activation of the AKT/glycogen synthase kinase (GSK) pathway were elevated in both NCTC 1469 cells and HEP 1–6 cells transfected with miR-19a mimics (Fig. 2c–f). In contrast, the level of miR-19a was decreased to 30-40% compared with those transfected with miRNA inhibitor control (Fig. 2g,h). Inhibition of miR-19a blocked glycogenesis (Fig. 2i,j) and the activation of the PI3K/AKT pathway (Fig. 2k,l).

Bottom Line: Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms.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.

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