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Gluconeogenesis, lipogenesis, and HBV replication are commonly regulated by PGC-1α-dependent pathway.

Jhuang HJ, Hsu WH, Lin KT, Hsu SL, Wang FS, Chou CK, Lee KH, Tsou AP, Lai JM, Yeh SF, Huang CY - Oncotarget (2015)

Bottom Line: We found that 8-Br-cAMP and glucocorticoids synergistically induce PGC-1α and its downstream targets, including PEPCK and G6Pase.HH-F3 also inhibited fatty acid synthase (FASN) expression and decreased lipid accumulation by down-regulating PGC-1α.HH-F3 may have potential use for the treatment of chronic hepatitis B patients with associated metabolic syndrome.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.

ABSTRACT
PGC-1α, a major metabolic regulator of gluconeogenesis and lipogenesis, is strongly induced to coactivate Hepatitis B virus (HBV) gene expression in the liver of fasting mice. We found that 8-Br-cAMP and glucocorticoids synergistically induce PGC-1α and its downstream targets, including PEPCK and G6Pase. Also, HBV core promoter activity was synergistically enhanced by 8-Br-cAMP and glucocorticoids. Graptopetalum paraguayense (GP), a herbal medicine, is commonly used in Taiwan to treat liver disorders. Partially purified fraction of GP (named HH-F3) suppressed 8-Br-cAMP/glucocorticoid-induced G6Pase, PEPCK and PGC-1α expression and suppressed HBV core promoter activity. HH-F3 blocked HBV core promoter activity via inhibition of PGC-1α expression. Ectopically expressed PGC-1α rescued HH-F3-inhibited HBV surface antigen expression, HBV mRNA production, core protein levels, and HBV replication. HH-F3 also inhibited fatty acid synthase (FASN) expression and decreased lipid accumulation by down-regulating PGC-1α. Thus, HH-F3 can inhibit HBV replication, gluconeogenesis and lipogenesis by down-regulating PGC-1α. Our study indicates that targeting PGC-1α may be a therapeutic strategy for treatment of HBV infections. HH-F3 may have potential use for the treatment of chronic hepatitis B patients with associated metabolic syndrome.

No MeSH data available.


Related in: MedlinePlus

HH-F3 suppresses 8-bromo-cAMP/dexamethasone-induced gluconeogenic enzymesG6Pase and PEPCK gene expression, and G6Pase promoter activityHuman hepatoma Hep3B/T2 cells were pre-treated with 0.5 mM 8-bromo-cAMP (8-Br-cAMP) alone or 0.5 μM dexamethasone (Dex) alone or both for 30 minutes. Different concentrations of HH-F3 were then added in serum-free DMEM for 24 h. The mRNAs of the gluconeogenic genes (A)PEPCK and (B)G6Pase were isolated and measured by Q-RT PCR and normalized to β-actin. Insulin was used as a positive control. (C) For the promoter activity assay, Hep3B/T2 cells were transfected with luciferase reporter plasmids driven by the G6Pase promoter. The luciferase activities were normalized to the β-galactosidase activity from co-transfected pCMV-β-galactosidase plasmids. *P < 0.05 compared with the vehicle group. #P < 0.05, ##P < 0.01 compared with the 8-Br-cAMP/Dex-induced group (n = 3).
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Figure 2: HH-F3 suppresses 8-bromo-cAMP/dexamethasone-induced gluconeogenic enzymesG6Pase and PEPCK gene expression, and G6Pase promoter activityHuman hepatoma Hep3B/T2 cells were pre-treated with 0.5 mM 8-bromo-cAMP (8-Br-cAMP) alone or 0.5 μM dexamethasone (Dex) alone or both for 30 minutes. Different concentrations of HH-F3 were then added in serum-free DMEM for 24 h. The mRNAs of the gluconeogenic genes (A)PEPCK and (B)G6Pase were isolated and measured by Q-RT PCR and normalized to β-actin. Insulin was used as a positive control. (C) For the promoter activity assay, Hep3B/T2 cells were transfected with luciferase reporter plasmids driven by the G6Pase promoter. The luciferase activities were normalized to the β-galactosidase activity from co-transfected pCMV-β-galactosidase plasmids. *P < 0.05 compared with the vehicle group. #P < 0.05, ##P < 0.01 compared with the 8-Br-cAMP/Dex-induced group (n = 3).

Mentions: To examine the effects of GP and HH-F3 on gluconeogenesis in HCC, the Hep3B/T2 hepatoma cell line expressing HBV was pretreated with 8-Bromo-cAMP and dexamethasone (8-Br-cAMP/Dex) for 30 min and then was treated with HH-F3 for 24 h. All of the reagents used, including 8-Br-cAMP, dexamethasone, and HH-F3 (20 μg/ml), did not affect cell viability within 24 h (Supplementary Figure 1). Consistent with previous studies, 8-Br-cAMP/Dex could synergistically activate gene expression of key gluconeogenic genes, including phosphoenol pyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), in Hep3B/T2 cells. Treatment with HH-F3 suppressed 8-Br-cAMP/Dex-induced PEPCK and G6Pase gene expression dose-dependently (Figure 2A and 2B). Similarly, the incubation of Hep3B/T2 cells with 8-Br-cAMP/Dex increased G6Pase promoter activity. Exposure to HH-F3 significantly reduced 8-Br-cAMP/Dex-induced G6Pase promoter activity (Figure 2C). These results indicate that HH-F3 can inhibit key gluconeogenic enzyme gene expression.


Gluconeogenesis, lipogenesis, and HBV replication are commonly regulated by PGC-1α-dependent pathway.

Jhuang HJ, Hsu WH, Lin KT, Hsu SL, Wang FS, Chou CK, Lee KH, Tsou AP, Lai JM, Yeh SF, Huang CY - Oncotarget (2015)

HH-F3 suppresses 8-bromo-cAMP/dexamethasone-induced gluconeogenic enzymesG6Pase and PEPCK gene expression, and G6Pase promoter activityHuman hepatoma Hep3B/T2 cells were pre-treated with 0.5 mM 8-bromo-cAMP (8-Br-cAMP) alone or 0.5 μM dexamethasone (Dex) alone or both for 30 minutes. Different concentrations of HH-F3 were then added in serum-free DMEM for 24 h. The mRNAs of the gluconeogenic genes (A)PEPCK and (B)G6Pase were isolated and measured by Q-RT PCR and normalized to β-actin. Insulin was used as a positive control. (C) For the promoter activity assay, Hep3B/T2 cells were transfected with luciferase reporter plasmids driven by the G6Pase promoter. The luciferase activities were normalized to the β-galactosidase activity from co-transfected pCMV-β-galactosidase plasmids. *P < 0.05 compared with the vehicle group. #P < 0.05, ##P < 0.01 compared with the 8-Br-cAMP/Dex-induced group (n = 3).
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Related In: Results  -  Collection

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Figure 2: HH-F3 suppresses 8-bromo-cAMP/dexamethasone-induced gluconeogenic enzymesG6Pase and PEPCK gene expression, and G6Pase promoter activityHuman hepatoma Hep3B/T2 cells were pre-treated with 0.5 mM 8-bromo-cAMP (8-Br-cAMP) alone or 0.5 μM dexamethasone (Dex) alone or both for 30 minutes. Different concentrations of HH-F3 were then added in serum-free DMEM for 24 h. The mRNAs of the gluconeogenic genes (A)PEPCK and (B)G6Pase were isolated and measured by Q-RT PCR and normalized to β-actin. Insulin was used as a positive control. (C) For the promoter activity assay, Hep3B/T2 cells were transfected with luciferase reporter plasmids driven by the G6Pase promoter. The luciferase activities were normalized to the β-galactosidase activity from co-transfected pCMV-β-galactosidase plasmids. *P < 0.05 compared with the vehicle group. #P < 0.05, ##P < 0.01 compared with the 8-Br-cAMP/Dex-induced group (n = 3).
Mentions: To examine the effects of GP and HH-F3 on gluconeogenesis in HCC, the Hep3B/T2 hepatoma cell line expressing HBV was pretreated with 8-Bromo-cAMP and dexamethasone (8-Br-cAMP/Dex) for 30 min and then was treated with HH-F3 for 24 h. All of the reagents used, including 8-Br-cAMP, dexamethasone, and HH-F3 (20 μg/ml), did not affect cell viability within 24 h (Supplementary Figure 1). Consistent with previous studies, 8-Br-cAMP/Dex could synergistically activate gene expression of key gluconeogenic genes, including phosphoenol pyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), in Hep3B/T2 cells. Treatment with HH-F3 suppressed 8-Br-cAMP/Dex-induced PEPCK and G6Pase gene expression dose-dependently (Figure 2A and 2B). Similarly, the incubation of Hep3B/T2 cells with 8-Br-cAMP/Dex increased G6Pase promoter activity. Exposure to HH-F3 significantly reduced 8-Br-cAMP/Dex-induced G6Pase promoter activity (Figure 2C). These results indicate that HH-F3 can inhibit key gluconeogenic enzyme gene expression.

Bottom Line: We found that 8-Br-cAMP and glucocorticoids synergistically induce PGC-1α and its downstream targets, including PEPCK and G6Pase.HH-F3 also inhibited fatty acid synthase (FASN) expression and decreased lipid accumulation by down-regulating PGC-1α.HH-F3 may have potential use for the treatment of chronic hepatitis B patients with associated metabolic syndrome.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.

ABSTRACT
PGC-1α, a major metabolic regulator of gluconeogenesis and lipogenesis, is strongly induced to coactivate Hepatitis B virus (HBV) gene expression in the liver of fasting mice. We found that 8-Br-cAMP and glucocorticoids synergistically induce PGC-1α and its downstream targets, including PEPCK and G6Pase. Also, HBV core promoter activity was synergistically enhanced by 8-Br-cAMP and glucocorticoids. Graptopetalum paraguayense (GP), a herbal medicine, is commonly used in Taiwan to treat liver disorders. Partially purified fraction of GP (named HH-F3) suppressed 8-Br-cAMP/glucocorticoid-induced G6Pase, PEPCK and PGC-1α expression and suppressed HBV core promoter activity. HH-F3 blocked HBV core promoter activity via inhibition of PGC-1α expression. Ectopically expressed PGC-1α rescued HH-F3-inhibited HBV surface antigen expression, HBV mRNA production, core protein levels, and HBV replication. HH-F3 also inhibited fatty acid synthase (FASN) expression and decreased lipid accumulation by down-regulating PGC-1α. Thus, HH-F3 can inhibit HBV replication, gluconeogenesis and lipogenesis by down-regulating PGC-1α. Our study indicates that targeting PGC-1α may be a therapeutic strategy for treatment of HBV infections. HH-F3 may have potential use for the treatment of chronic hepatitis B patients with associated metabolic syndrome.

No MeSH data available.


Related in: MedlinePlus