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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

PTEN participates in miR-19a-mediated glycogenesis in hepatocytes.Protein levels and mRNA levels (a) of PTEN in the NCTC 1469 cells transfected with siRNA (si-1519) targeting PTEN mRNA or with negative siRNA control. Down-regulation of PTEN rescued the effects of miR-19a inhibitor suppression on the activation of the AKT/GSK pathway (d and e) and improved glycogenesis (b and c) in NCTC 1469 cells and HEP 1–6cells. PTEN did not affect the glycogenesis after treatment with PI3K inhibitor LY294002 (f and g) . The molecular mechanism by which PTEN participates in miR-19a-mediated glycogenesis in hepatocytes (h). Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs. control or miR-19a inhibitor or LY294002). Full-length blots are presented in the supplementary information (supplementary Figure S5).
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f5: PTEN participates in miR-19a-mediated glycogenesis in hepatocytes.Protein levels and mRNA levels (a) of PTEN in the NCTC 1469 cells transfected with siRNA (si-1519) targeting PTEN mRNA or with negative siRNA control. Down-regulation of PTEN rescued the effects of miR-19a inhibitor suppression on the activation of the AKT/GSK pathway (d and e) and improved glycogenesis (b and c) in NCTC 1469 cells and HEP 1–6cells. PTEN did not affect the glycogenesis after treatment with PI3K inhibitor LY294002 (f and g) . The molecular mechanism by which PTEN participates in miR-19a-mediated glycogenesis in hepatocytes (h). Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs. control or miR-19a inhibitor or LY294002). Full-length blots are presented in the supplementary information (supplementary Figure S5).

Mentions: To gain further insights into the role of PTEN in miR-19a-mediated glycogenesis, siRNA (si-1519) targeting PTEN mRNA was transfected into NCTC 1469 cells and HEP 1–6 cells. Both the protein levels and mRNA levels of PTEN were decreased by 30–40% compared with those transfected with negative siRNA control (Fig. 5a). Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NCTC 1469 cells and HEP 1–6 cells (Fig. 5d,e). Moreover, PTEN did not affect glycogenesis after treatment with PI3K inhibitor LY294002 (Fig. 5f,g). In conclusion, as shown in Fig. 5h, PTEN participates in miR-19a-mediated glycogenesis in hepatocytes via regulation of the AKT/GSK pathway.


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)

PTEN participates in miR-19a-mediated glycogenesis in hepatocytes.Protein levels and mRNA levels (a) of PTEN in the NCTC 1469 cells transfected with siRNA (si-1519) targeting PTEN mRNA or with negative siRNA control. Down-regulation of PTEN rescued the effects of miR-19a inhibitor suppression on the activation of the AKT/GSK pathway (d and e) and improved glycogenesis (b and c) in NCTC 1469 cells and HEP 1–6cells. PTEN did not affect the glycogenesis after treatment with PI3K inhibitor LY294002 (f and g) . The molecular mechanism by which PTEN participates in miR-19a-mediated glycogenesis in hepatocytes (h). Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs. control or miR-19a inhibitor or LY294002). Full-length blots are presented in the supplementary information (supplementary Figure S5).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: PTEN participates in miR-19a-mediated glycogenesis in hepatocytes.Protein levels and mRNA levels (a) of PTEN in the NCTC 1469 cells transfected with siRNA (si-1519) targeting PTEN mRNA or with negative siRNA control. Down-regulation of PTEN rescued the effects of miR-19a inhibitor suppression on the activation of the AKT/GSK pathway (d and e) and improved glycogenesis (b and c) in NCTC 1469 cells and HEP 1–6cells. PTEN did not affect the glycogenesis after treatment with PI3K inhibitor LY294002 (f and g) . The molecular mechanism by which PTEN participates in miR-19a-mediated glycogenesis in hepatocytes (h). Data represent the mean ± S.D. N = 3 independent experiments. *p < 0.05; **p < 0.01by ANOVAtest (vs. control or miR-19a inhibitor or LY294002). Full-length blots are presented in the supplementary information (supplementary Figure S5).
Mentions: To gain further insights into the role of PTEN in miR-19a-mediated glycogenesis, siRNA (si-1519) targeting PTEN mRNA was transfected into NCTC 1469 cells and HEP 1–6 cells. Both the protein levels and mRNA levels of PTEN were decreased by 30–40% compared with those transfected with negative siRNA control (Fig. 5a). Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NCTC 1469 cells and HEP 1–6 cells (Fig. 5d,e). Moreover, PTEN did not affect glycogenesis after treatment with PI3K inhibitor LY294002 (Fig. 5f,g). In conclusion, as shown in Fig. 5h, PTEN participates in miR-19a-mediated glycogenesis in hepatocytes via regulation of the AKT/GSK pathway.

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