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Transcription factor Nrf2 regulates SHP and lipogenic gene expression in hepatic lipid metabolism.

ABSTRACT: Nuclear factor erythroid-2 related factor 2 (Nrf2) plays a pivotal role in cytoprotection against both endogenous and exogenous stresses. Here, we establish a novel molecular link between Nrf2, nuclear receptor small heterodimer partner (SHP; NROB2), lipogenic genes, and hepatic lipid homeostasis. Deletion of Nrf2 (Nrf2?(/)?) in mice resulted in a reduced liver weight, a decrease in fatty acid content of hepatic triacylglycerol, as well as concomitant increases in the levels of serum VLDL-triglyceride (TG), HDL cholesterol, and ketone bodies at 6 mo of age. Liver weight and hepatic TG content were consistently lower in Nrf2?(/)? mice upon a high-fat challenge. This phenotype was accompanied by downregulation of genes in lipid synthesis and uptake and upregulation of genes in lipid oxidation in older Nrf2?(/)? mice. Interestingly, SHP expression was induced with age in Nrf2(+/+) mice but decreased by Nrf2 deficiency. Forced expression and activation of Nrf2 by Nrf2 activators consistently induced SHP expression, and Nrf2 was identified as a novel activator of the SHP gene transcription. We also identified PPAR-?, Fas, Scd1, and Srebp-1 as direct targets of Nrf2 activation. These findings provide evidence for a role of Nrf2 in the modulation of hepatic lipid homeostasis through transcriptional activation of SHP and lipogenic gene expression.

SUBMITTER: Huang J

PROVIDER: S-EPMC3006243 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

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Transcription factor Nrf2 regulates SHP and lipogenic gene expression in hepatic lipid metabolism.

Huang Jiansheng J Tabbi-Anneni Imene I Gunda Viswanath V Wang Li L

American journal of physiology. Gastrointestinal and liver physiology 20101007 6

Nuclear factor erythroid-2 related factor 2 (Nrf2) plays a pivotal role in cytoprotection against both endogenous and exogenous stresses. Here, we establish a novel molecular link between Nrf2, nuclear receptor small heterodimer partner (SHP; NROB2), lipogenic genes, and hepatic lipid homeostasis. Deletion of Nrf2 (Nrf2⁻(/)⁻) in mice resulted in a reduced liver weight, a decrease in fatty acid content of hepatic triacylglycerol, as well as concomitant increases in the levels of serum VLDL-trigly ...[more]

PMID: 20930048

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Project description:AIM:To investigate the effects of blueberry on hepatic fibrosis and NF-E2-related factor 2 (Nrf2) transcription factor in rats. METHODS:Forty-five male Sprague-Dawley rats were randomly divided into control group (A); CCl(4)-induced hepatic fibrosis group (B); blueberry prevention group (C); Dan-shao-hua-xian capsule (DSHX) prevention group (D); and blueberry + DSHX prevention group (E). Liver fibrosis was induced in rats by subcutaneous injection of CCl(4) and a high-lipid/low-protein diet for 8 wk (except the control group). The level of hyaluronic acid (HA) and alanine aminotransferase (ALT) in serum was examined. The activity of superoxide dismutase (SOD), glutathione-S-transferase (GST) and malondialdehyde (MDA) in liver homogenates was determined. The degree of hepatic fibrosis was evaluated by hematoxylin and eosin and Masson staining. Expression of Nrf2 and NADPH quinone oxidoreductase 1 (Nqo1) was detected by real-time reversed transcribed-polymerase chain reaction, immunohistochemical techniques, and western blotting. RESULTS:Compared with group B, liver indices, levels of serum HA and ALT of groups C, D and E were reduced (liver indices: 0.038 +/- 0.008, 0.036 +/- 0.007, 0.036 +/- 0.005 vs 0.054 +/- 0.009, P < 0.05; HA: 502.33 +/- 110.57 ng/mL, 524.25 +/- 255.42 ng/mL, 499.25 +/- 198.10 ng/mL vs 828.50 +/- 237.83 ng/mL, P < 0.05; ALT: 149.44 +/- 16.51 U/L, 136.88 +/- 10.07 U/L, 127.38 +/- 11.03 U/L vs 203.25 +/- 31.62 U/L, P < 0.05), and SOD level was significantly higher, but MDA level was lower, in liver homogenates (SOD: 1.36 +/- 0.09 U/mg, 1.42 +/- 0.13 U/mg, 1.50 +/- 0.15 U/mg vs 1.08 +/- 0.19 U/mg, P < 0.05; MDA: 0.294 +/- 0.026 nmol/mg, 0.285 +/- 0.025 nmol/mg, 0.284 +/- 0.028 nmol/mg vs 0.335 +/- 0.056 nmol/mg, P < 0.05). Meanwhile, the stage of hepatic fibrosis was significantly weakened (P < 0.05). Compared with group A, the activity of GST liver homogenates and expression levels of Nrf2 and Nqo1 in group B were elevated (P < 0.05). The expression level of Nrf2 and Nqo1 in groups C, D, and E were increased as compared with group B, but the difference was not significant. CONCLUSION:Blueberry has preventive and protective effects on CCl(4)-induced hepatic fibrosis by reducing hepatocyte injury and lipid peroxidation. However, these effects may not be related to the activation of Nrf2 during long-term of CCl(4).

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Transcription factor Nrf2 regulates SHP and lipogenic gene expression in hepatic lipid metabolism.

Publications

Transcription factor Nrf2 regulates SHP and lipogenic gene expression in hepatic lipid metabolism.

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