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Sample records for fenofibrate activates ampk

  1. Fenofibrate

    Science.gov (United States)

    ... atherosclerosis) decreases the blood flow and, therefore, the oxygen supply to the heart, brain, and other parts ... to take fenofibrate.tell your doctor if you drink or have ever drunk large amounts of alcohol ...

  2. Fenofibrate activates Nrf2 through p62-dependent Keap1 degradation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Su [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kang, Dong Hoon [Department of Life Science and Ewha Research Center for Systems Biology (Korea, Republic of); The Research Center for Cell Homeostasis, Ewha Womans University, Seoul 127-750 (Korea, Republic of); Lee, Da Hyun [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Bae, Soo Han, E-mail: soohanbae@yuhs.ac [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

    2015-09-25

    Peroxisome proliferator-activated receptor α (PPARα) activates the β-oxidation of fatty acids in the liver. Fenofibrate is a potent agonist of PPARα and is used in the treatment of hyperlipidemia. Fenofibrate treatment often induces the production of intracellular reactive oxygen species (ROS), leading to cell death. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is an essential component of the defense mechanism against oxidative stress. However, the molecular mechanism underlying the regulation of the Nrf2-Keap1 pathway in fenofibrate-induced cell death is not known. In this study, we demonstrated that fenofibrate induces Keap1 degradation and Nrf2 activation. This fenofibrate-mediated Keap1 degradation is partly dependent on autophagy. Furthermore, fenofibrate-induced Keap1 degradation followed by Nrf2 activation is mainly mediated by p62, which functions as an adaptor protein in the autophagic pathway. Consistent with these findings, ablation of p62 increased fenofibrate-mediated apoptotic cell death associated with ROS accumulation. These results strongly suggest that p62 plays a crucial role in preventing fenofibrate-induced cell death. - Highlights: • Fenofibrate induces cell death by increasing ROS production. • The underlying defense mechanism against this effect is unknown. • Fenofibrate induces autophagy-dependent Keap1 degradation and Nrf2 activation. • This process is p62-dependent; lack of p62 enhanced fenofibrate-mediated apoptosis. • p62 plays a crucial role in preventing fenofibrate-induced cell death.

  3. The nuclear protein Artemis promotes AMPK activation by stabilizing the LKB1-AMPK complex

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Koji, E-mail: k_nakagawa@pharm.hokudai.ac.jp [Department of Pathophysiology and Therapeutics, Division of Pharmascience, Faculty of Pharmaceutical Sciences, Hokkaido University, N12 W6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Uehata, Yasuko; Natsuizaka, Mitsuteru; Kohara, Toshihisa; Darmanin, Stephanie [Department of Gastroenterology and Hematology, Graduate School of Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Asaka, Masahiro [Department of Gastroenterology and Hematology, Graduate School of Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Department of Cancer Preventive Medicine, Graduate School of Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Takeda, Hiroshi [Department of Pathophysiology and Therapeutics, Division of Pharmascience, Faculty of Pharmaceutical Sciences, Hokkaido University, N12 W6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Department of Gastroenterology and Hematology, Graduate School of Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Kobayashi, Masanobu [Department of Cancer Preventive Medicine, Graduate School of Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); School of Nursing and Social Services, Health Sciences University of Hokkaido, Ishikari-Toubetsu, Hokkaido 061-0293 (Japan)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer The nuclear protein Artemis physically interacts with AMPK{alpha}2. Black-Right-Pointing-Pointer Artemis co-localizes with AMPK{alpha}2 in the nucleus. Black-Right-Pointing-Pointer Artemis promotes phosphorylation and activation of AMPK. Black-Right-Pointing-Pointer The interaction between AMPK{alpha}2 and LKB1 is stabilized by Artemis. -- Abstract: AMP-activated protein kinase (AMPK) is a hetero-trimeric Ser/Thr kinase composed of a catalytic {alpha} subunit and regulatory {beta} and {gamma} subunits; it functions as an energy sensor that controls cellular energy homeostasis. In response to an increased cellular AMP/ATP ratio, AMPK is activated by phosphorylation at Thr172 in the {alpha}-subunit by upstream AMPK kinases (AMPKKs), including tumor suppressor liver kinase B1 (LKB1). To elucidate more precise molecular mechanisms of AMPK activation, we performed yeast two-hybrid screening and isolated the complementary DNA (cDNA) encoding the nuclear protein Artemis/DNA cross-link repair 1C (DCLRE1C) as an AMPK{alpha}2-binding protein. Artemis was found to co-immunoprecipitate with AMPK{alpha}2, and the co-localization of Artemis with AMPK{alpha}2 in the nucleus was confirmed by immunofluorescence staining in U2OS cells. Moreover, over-expression of Artemis enhanced the phosphorylation of AMPK{alpha}2 and the AMPK substrate acetyl-CoA carboxylase (ACC). Conversely, RNAi-mediated knockdown of Artemis reduced AMPK and ACC phosphorylation. In addition, Artemis markedly increased the physical association between AMPK{alpha}2 and LKB1. Taken together, these results suggest that Artemis functions as a positive regulator of AMPK signaling by stabilizing the LKB1-AMPK complex.

  4. AMPK Activation Affects Glutamate Metabolism in Astrocytes

    DEFF Research Database (Denmark)

    Voss, Caroline Marie; Pajęcka, Kamilla; Stridh, Malin H

    2015-01-01

    acid (TCA) cycle was studied using high-performance liquid chromatography analysis supplemented with gas chromatography-mass spectrometry technology. It was found that AMPK activation had profound effects on the pathways involved in glutamate metabolism since the entrance of the glutamate carbon...... skeleton into the TCA cycle was reduced. On the other hand, glutamate uptake into the astrocytes as well as its conversion to glutamine catalyzed by glutamine synthetase was not affected by AMPK activation. Interestingly, synthesis and release of citrate, which are hallmarks of astrocytic function, were...

  5. How is AMPK activity regulated in skeletal muscles during exercise?

    DEFF Research Database (Denmark)

    Jørgensen, Sebastian Beck; Rose, Adam John

    2008-01-01

    AMPK is a metabolic "master" controller activated in skeletal muscle by exercise in a time and intensity dependent manner, and has been implicated in regulating metabolic pathways in muscle during physical exercise. AMPK signaling in skeletal muscle is regulated by several systemic...... and intracellular factors and the regulation of skeletal muscle AMPK in response to exercise is the focus of this review. Specifically, the role of LKB1 and phosphatase PP2C in nucleotide-dependent activation of AMPK, and ionized calcium in CaMKK-dependent activation of AMPK in working muscle is discussed. We also...

  6. How is AMPK activity regulated in skeletal muscles during exercise?

    DEFF Research Database (Denmark)

    Jørgensen, Sebastian Beck; Rose, Adam John

    2008-01-01

    AMPK is a metabolic "master" controller activated in skeletal muscle by exercise in a time and intensity dependent manner, and has been implicated in regulating metabolic pathways in muscle during physical exercise. AMPK signaling in skeletal muscle is regulated by several systemic...... and intracellular factors and the regulation of skeletal muscle AMPK in response to exercise is the focus of this review. Specifically, the role of LKB1 and phosphatase PP2C in nucleotide-dependent activation of AMPK, and ionized calcium in CaMKK-dependent activation of AMPK in working muscle is discussed. We also...... discuss the influence of reactive oxygen species produced within the muscle as well as muscle glycogen and TAK1 in regulating AMPK during exercise. Currently, during intensive contraction, activation of alpha2-AMPK seems mainly to rely on AMP accumulating from ATP-hydrolysis whereas calcium signaling may...

  7. Arctigenin alleviates ER stress via activating AMPK

    Science.gov (United States)

    Gu, Yuan; Sun, Xiao-xiao; Ye, Ji-ming; He, Li; Yan, Shou-sheng; Zhang, Hao-hao; Hu, Li-hong; Yuan, Jun-ying; Yu, Qiang

    2012-01-01

    Aim: To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms. Methods: A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKβ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels. Results: ATG (2.5, 5 and 10 μmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 μmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 μmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 μmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 μmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 β cells. Conclusion: ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load. PMID:22705729

  8. The nuclear protein Artemis promotes AMPK activation by stabilizing the LKB1–AMPK complex

    International Nuclear Information System (INIS)

    Nakagawa, Koji; Uehata, Yasuko; Natsuizaka, Mitsuteru; Kohara, Toshihisa; Darmanin, Stephanie; Asaka, Masahiro; Takeda, Hiroshi; Kobayashi, Masanobu

    2012-01-01

    Highlights: ► The nuclear protein Artemis physically interacts with AMPKα2. ► Artemis co-localizes with AMPKα2 in the nucleus. ► Artemis promotes phosphorylation and activation of AMPK. ► The interaction between AMPKα2 and LKB1 is stabilized by Artemis. -- Abstract: AMP-activated protein kinase (AMPK) is a hetero-trimeric Ser/Thr kinase composed of a catalytic α subunit and regulatory β and γ subunits; it functions as an energy sensor that controls cellular energy homeostasis. In response to an increased cellular AMP/ATP ratio, AMPK is activated by phosphorylation at Thr172 in the α-subunit by upstream AMPK kinases (AMPKKs), including tumor suppressor liver kinase B1 (LKB1). To elucidate more precise molecular mechanisms of AMPK activation, we performed yeast two-hybrid screening and isolated the complementary DNA (cDNA) encoding the nuclear protein Artemis/DNA cross-link repair 1C (DCLRE1C) as an AMPKα2-binding protein. Artemis was found to co-immunoprecipitate with AMPKα2, and the co-localization of Artemis with AMPKα2 in the nucleus was confirmed by immunofluorescence staining in U2OS cells. Moreover, over-expression of Artemis enhanced the phosphorylation of AMPKα2 and the AMPK substrate acetyl-CoA carboxylase (ACC). Conversely, RNAi-mediated knockdown of Artemis reduced AMPK and ACC phosphorylation. In addition, Artemis markedly increased the physical association between AMPKα2 and LKB1. Taken together, these results suggest that Artemis functions as a positive regulator of AMPK signaling by stabilizing the LKB1–AMPK complex.

  9. Fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of LncRNA MEG3

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Duanmin [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Su, Cunjin [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Jiang, Min [Department of Breast Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shen, Yating [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shi, Aiming; Zhao, Fenglun [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Chen, Ruidong [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shen, Zhu [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Bao, Junjie, E-mail: baojjsdfey@sina.com [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Tang, Wen, E-mail: sztangwen@163.com [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China)

    2016-03-04

    There is still no suitable drug for pancreatic cancer treatment, which is one of the most aggressive human tumors. Maternally expressed gene 3 (MEG3), a LncRNA, has been suggested as a tumor suppressor in a range of human tumors. Studies found fenofibrate exerted anti-tumor roles in various human cancer cell lines. However, its role in pancreatic cancer remains unknown. The present study aimed to explore the impacts of fenofibrate on pancreatic cancer cell lines, and to investigate MEG3 role in its anti-tumor mechanisms. We used MTT assay to determine cells proliferation, genome-wide LncRNA microarray analysis to identify differently expressed LncRNAs, siRNA or pCDNA-MEG3 transfection to interfere or upregulate MEG3 expression, western blot to detect protein levels, real-time PCR to determine MEG3 level. Fenofibrate significantly inhibited proliferation of pancreatic cancer cells, increased MEG3 expression and p53 levels. Moreover, knockdown of MEG3 attenuated cytotoxicity induced by fenofibrate. Furthermore, overexpression of MEG3 induced cells death and increased p53 expression. Our results indicated fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of MEG3. - Highlights: • We found that fenofibrate suppressed proliferation of pancreatic cancer cells. • We found fenofibrate increased LncRNA-MEG3 expression and p53 level in PANC-1 cells. • Inhibition of MEG3 expression attenuated anti-tumor effects of fenofibrate.

  10. The PPARα Agonist Fenofibrate Preserves Hippocampal Neurogenesis and Inhibits Microglial Activation After Whole-Brain Irradiation

    International Nuclear Information System (INIS)

    Ramanan, Sriram; Kooshki, Mitra; Zhao Weiling; Hsu, F.-C.; Riddle, David R.; Robbins, Mike E.

    2009-01-01

    Purpose: Whole-brain irradiation (WBI) leads to cognitive impairment months to years after radiation. Numerous studies suggest that decreased hippocampal neurogenesis and microglial activation are involved in the pathogenesis of WBI-induced brain injury. The goal of this study was to investigate whether administration of the peroxisomal proliferator-activated receptor (PPAR) α agonist fenofibrate would prevent the detrimental effect of WBI on hippocampal neurogenesis. Methods and Materials: For this study, 129S1/SvImJ wild-type and PPARα knockout mice that were fed either regular or 0.2% wt/wt fenofibrate-containing chow received either sham irradiation or WBI (10-Gy single dose of 137 Cs γ-rays). Mice were injected intraperitoneally with bromodeoxyuridine to label the surviving cells at 1 month after WBI, and the newborn neurons were counted at 2 months after WBI by use of bromodeoxyuridine/neuronal nuclei double immunofluorescence. Proliferation in the subgranular zone and microglial activation were measured at 1 week and 2 months after WBI by use of Ki-67 and CD68 immunohistochemistry, respectively. Results: Whole-brain irradiation led to a significant decrease in the number of newborn hippocampal neurons 2 months after it was performed. Fenofibrate prevented this decrease by promoting the survival of newborn cells in the dentate gyrus. In addition, fenofibrate treatment was associated with decreased microglial activation in the dentate gyrus after WBI. The neuroprotective effects of fenofibrate were abolished in the knockout mice, indicating a PPARα-dependent mechanism or mechanisms. Conclusions: These data highlight a novel role for PPARα ligands in improving neurogenesis after WBI and offer the promise of improving the quality of life for brain cancer patients receiving radiotherapy.

  11. Exercise-induced AMPK activity in skeletal muscle

    DEFF Research Database (Denmark)

    Friedrichsen, Martin; Mortensen, Brynjulf; Pehmøller, Christian

    2013-01-01

    The energy/fuel sensor 5'-AMP-activated protein kinase (AMPK) is viewed as a master regulator of cellular energy balance due to its many roles in glucose, lipid, and protein metabolism. In this review we focus on the regulation of AMPK activity in skeletal muscle and its involvement in glucose...

  12. Fenofibrate, a peroxisome proliferator-activated receptor α ligand, prevents abnormal liver function induced by a fasting–refeeding process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon No; Dutta, Raghbendra Kumar; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Yoo, Kyeong-Won [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Immune-network Pioneer Research Center, Department of Biochemistry, College of Medicine, Dong-A University, Busan (Korea, Republic of); Song, Seung Ryel [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Park, Do-Sim [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Department of Laboratory of Medicine, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); So, Hong-Seob [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Park, Raekil, E-mail: rkpark@wku.ac.kr [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of)

    2013-12-06

    Highlights: •A fasting–refeeding high fat diet (HDF) model mimics irregular eating habit. •A fasting–refeeding HFD induces liver ballooning injury. •A fasting–refeeding HDF process elicits hepatic triglyceride accumulation. •Fenofibrate, PPARα ligand, prevents liver damage induced by refeeding HFD. -- Abstract: Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is an anti-hyperlipidemic agent that has been widely used in the treatment of dyslipidemia. In this study, we examined the effect of fenofibrate on liver damage caused by refeeding a high-fat diet (HFD) in mice after 24 h fasting. Here, we showed that refeeding HFD after fasting causes liver damage in mice determined by liver morphology and liver cell death. A detailed analysis revealed that hepatic lipid droplet formation is enhanced and triglyceride levels in liver are increased by refeeding HFD after starvation for 24 h. Also, NF-κB is activated and consequently induces the expression of TNF-α, IL1-β, COX-2, and NOS2. However, treating with fenofibrate attenuates the liver damage and triglyceride accumulation caused by the fasting–refeeding HFD process. Fenofibrate reduces the expression of NF-κB target genes but induces genes for peroxisomal fatty acid oxidation, peroxisome biogenesis and mitochondrial fatty acid oxidation. These results strongly suggest that the treatment of fenofibrate ameliorates the liver damage induced by fasting–refeeding HFD, possibly through the activation of fatty acid oxidation.

  13. Fenofibrate, a peroxisome proliferator-activated receptor α ligand, prevents abnormal liver function induced by a fasting–refeeding process

    International Nuclear Information System (INIS)

    Lee, Joon No; Dutta, Raghbendra Kumar; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu; Yoo, Kyeong-Won; Song, Seung Ryel; Park, Do-Sim; So, Hong-Seob; Park, Raekil

    2013-01-01

    Highlights: •A fasting–refeeding high fat diet (HDF) model mimics irregular eating habit. •A fasting–refeeding HFD induces liver ballooning injury. •A fasting–refeeding HDF process elicits hepatic triglyceride accumulation. •Fenofibrate, PPARα ligand, prevents liver damage induced by refeeding HFD. -- Abstract: Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is an anti-hyperlipidemic agent that has been widely used in the treatment of dyslipidemia. In this study, we examined the effect of fenofibrate on liver damage caused by refeeding a high-fat diet (HFD) in mice after 24 h fasting. Here, we showed that refeeding HFD after fasting causes liver damage in mice determined by liver morphology and liver cell death. A detailed analysis revealed that hepatic lipid droplet formation is enhanced and triglyceride levels in liver are increased by refeeding HFD after starvation for 24 h. Also, NF-κB is activated and consequently induces the expression of TNF-α, IL1-β, COX-2, and NOS2. However, treating with fenofibrate attenuates the liver damage and triglyceride accumulation caused by the fasting–refeeding HFD process. Fenofibrate reduces the expression of NF-κB target genes but induces genes for peroxisomal fatty acid oxidation, peroxisome biogenesis and mitochondrial fatty acid oxidation. These results strongly suggest that the treatment of fenofibrate ameliorates the liver damage induced by fasting–refeeding HFD, possibly through the activation of fatty acid oxidation

  14. Activation of Sterol Regulatory Element Binding Factors by Fenofibrate and Gemfibrozil Stimulate Myelination in Zebrafish

    Directory of Open Access Journals (Sweden)

    Yuhei Nishimura

    2016-07-01

    Full Text Available Oligodendrocytes are major myelin-producing cells and play essential roles in the function of a healthy nervous system. However, they are also one of the most vulnerable neural cell types in the central nervous system (CNS, and myelin abnormalities in the CNS are found in a wide variety of neurological disorders, including multiple sclerosis, adrenoleukodystrophy, and schizophrenia. There is an urgent need to identify small molecular weight compounds that can stimulate myelination. In this study, we performed comparative transcriptome analysis to identify pharmacodynamic effects common to miconazole and clobetasol, which have been shown to stimulate myelination by mouse oligodendrocyte progenitor cells (OPCs. Of the genes differentially expressed in both miconazole- and clobetasol-treated mouse OPCs compared with untreated cells, we identified differentially expressed genes (DEGs common to both drug treatments. Gene ontology analysis revealed that these DEGs are significantly associated with the sterol biosynthetic pathway, and further bioinformatics analysis suggested that sterol regulatory element binding factors (SREBFs might be key upstream regulators of the DEGs. In silico screening of a public database for chemicals associated with SREBF activation identified fenofibrate, a peroxisome proliferator-activated receptor α (PPARα agonist, as a drug that increases the expression of known SREBF targets, raising the possibility that fenofibrate may also stimulate myelination. To test this, we performed in vivo imaging of zebrafish expressing a fluorescent reporter protein under the control of the myelin basic protein (mbp promoter. Treatment of zebrafish with fenofibrate significantly increased expression of the fluorescent reporter compared with untreated zebrafish. This increase was attenuated by co-treatment with fatostatin, a specific inhibitor of SREBFs, confirming that the fenofibrate effect was mediated via SREBFs. Furthermore, incubation

  15. Activation of Sterol Regulatory Element Binding Factors by Fenofibrate and Gemfibrozil Stimulates Myelination in Zebrafish.

    Science.gov (United States)

    Ashikawa, Yoshifumi; Nishimura, Yuhei; Okabe, Shiko; Sasagawa, Shota; Murakami, Soichiro; Yuge, Mizuki; Kawaguchi, Koki; Kawase, Reiko; Tanaka, Toshio

    2016-01-01

    Oligodendrocytes are major myelin-producing cells and play essential roles in the function of a healthy nervous system. However, they are also one of the most vulnerable neural cell types in the central nervous system (CNS), and myelin abnormalities in the CNS are found in a wide variety of neurological disorders, including multiple sclerosis, adrenoleukodystrophy, and schizophrenia. There is an urgent need to identify small molecular weight compounds that can stimulate myelination. In this study, we performed comparative transcriptome analysis to identify pharmacodynamic effects common to miconazole and clobetasol, which have been shown to stimulate myelination by mouse oligodendrocyte progenitor cells (OPCs). Of the genes differentially expressed in both miconazole- and clobetasol-treated mouse OPCs compared with untreated cells, we identified differentially expressed genes (DEGs) common to both drug treatments. Gene ontology analysis revealed that these DEGs are significantly associated with the sterol biosynthetic pathway, and further bioinformatics analysis suggested that sterol regulatory element binding factors (SREBFs) might be key upstream regulators of the DEGs. In silico screening of a public database for chemicals associated with SREBF activation identified fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, as a drug that increases the expression of known SREBF targets, raising the possibility that fenofibrate may also stimulate myelination. To test this, we performed in vivo imaging of zebrafish expressing a fluorescent reporter protein under the control of the myelin basic protein (mbp) promoter. Treatment of zebrafish with fenofibrate significantly increased expression of the fluorescent reporter compared with untreated zebrafish. This increase was attenuated by co-treatment with fatostatin, a specific inhibitor of SREBFs, confirming that the fenofibrate effect was mediated via SREBFs. Furthermore, incubation of zebrafish

  16. Etoposide induces ATM-dependent mitochondrial biogenesis through AMPK activation.

    Directory of Open Access Journals (Sweden)

    Xuan Fu

    2008-04-01

    Full Text Available DNA damage such as double-stranded DNA breaks (DSBs has been reported to stimulate mitochondrial biogenesis. However, the underlying mechanism is poorly understood. The major player in response to DSBs is ATM (ataxia telangiectasia mutated. Upon sensing DSBs, ATM is activated through autophosphorylation and phosphorylates a number of substrates for DNA repair, cell cycle regulation and apoptosis. ATM has been reported to phosphorylate the alpha subunit of AMP-activated protein kinase (AMPK, which senses AMP/ATP ratio in cells, and can be activated by upstream kinases. Here we provide evidence for a novel role of ATM in mitochondrial biogenesis through AMPK activation in response to etoposide-induced DNA damage.Three pairs of human ATM+ and ATM- cells were employed. Cells treated with etoposide exhibited an ATM-dependent increase in mitochondrial mass as measured by 10-N-Nonyl-Acridine Orange and MitoTracker Green FM staining, as well as an increase in mitochondrial DNA content. In addition, the expression of several known mitochondrial biogenesis regulators such as the major mitochondrial transcription factor NRF-1, PGC-1alpha and TFAM was also elevated in response to etoposide treatment as monitored by RT-PCR. Three pieces of evidence suggest that etoposide-induced mitochondrial biogenesis is due to ATM-dependent activation of AMPK. First, etoposide induced ATM-dependent phosphorylation of AMPK alpha subunit at Thr172, indicative of AMPK activation. Second, inhibition of AMPK blocked etoposide-induced mitochondrial biogenesis. Third, activation of AMPK by AICAR (an AMP analogue stimulated mitochondrial biogenesis in an ATM-dependent manner, suggesting that ATM may be an upstream kinase of AMPK in the mitochondrial biogenesis pathway.These results suggest that activation of ATM by etoposide can lead to mitochondrial biogenesis through AMPK activation. We propose that ATM-dependent mitochondrial biogenesis may play a role in DNA damage response

  17. Predominant alpha2/beta2/gamma3 AMPK activation during exercise in human skeletal muscle

    DEFF Research Database (Denmark)

    Birk, Jesper Bratz; Wojtaszewski, Jørgen

    2006-01-01

    -Thr-172 AMPK phosphorylation (r2 = 0.84, P important actor in exercise-regulated AMPK signalling in human skeletal muscle, probably mediating phosphorylation of ACCß.......5'AMP-activated protein kinase (AMPK) is a key regulator of cellular metabolism and is regulated in muscle during exercise. We have previously established that only three of 12 possible AMPK a/ß/¿-heterotrimers are present in human skeletal muscle. Previous studies describe discrepancies between...... total AMPK activity and regulation of its target acetyl-CoA-carboxylase (ACC)ß. Also, exercise training decreases expression of the regulatory ¿3 AMPK subunit and attenuates a2 AMPK activity during exercise. We hypothesize that these observations reflect a differential regulation of the AMPK...

  18. Effects of alpha-AMPK knockout on exercise-induced gene activation in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Jørgensen, Sebastian Beck; Wojtaszewski, Jørgen; Viollet, Benoit

    2005-01-01

    running (90 min), and in recovery. Running increased a1-AMPK kinase activity, phosphorylation (P) of AMPK, and acetyl-CoA carboxylase (ACC)ß in a2-WT and a2-KO muscles and increased a2-AMPK kinase activity in a2-WT. In a2-KO muscles, AMPK-P and ACCß-P were markedly lower compared with a2-WT. However, in a...

  19. Lack of metformin effect on mouse embryo AMPK activity: implications for metformin treatment during pregnancy.

    Science.gov (United States)

    Lee, Hyung-Yul; Wei, Dan; Loeken, Mary R

    2014-01-01

    Adenosine monophosphate-activated protein kinase (AMPK) is stimulated in embryos during diabetic pregnancy by maternal hyperglycaemia-induced embryo oxidative stress. Stimulation of AMPK disrupts embryo gene expression and causes neural tube defects. Metformin, which may be taken during early pregnancy, has been reported to stimulate AMPK activity. Thus, the benefits of improved glycaemic control could be offset by stimulated embryo AMPK activity. Here, we investigated whether metformin can stimulate AMPK activity in mouse embryos and can adversely affect embryo gene expression and neural tube defects. Pregnant nondiabetic mice were administered metformin beginning on the first day of pregnancy. Activation of maternal and embryo AMPK [phospho-AMPK α (Thr172) relative to total AMPK], expression of Pax3, a gene required for neural tube closure, and neural tube defects were studied. Mouse embryonic stem cells were used as a cell culture model of embryonic neuroepithelium to study metformin effects on AMPK and Pax3 expression. Metformin had no effect on AMPK in embryos or maternal skeletal muscle but increased activated AMPK in maternal liver. Metformin did not inhibit Pax3 expression or increase neural tube defects. However, metformin increased activated AMPK and inhibited Pax3 expression by mouse embryonic stem cells. Mate1/Slc47a1 and Oct3/Slc22a, which encode metformin transporters, were expressed at barely detectable levels by embryos. Although metformin can have effects associated with diabetic embryopathy in vitro, the lack of effects on mouse embryos in vivo may be due to lack of metformin transporters and indicates that the benefits of metformin on glycaemic control are not counteracted by stimulation of embryo AMPK activity and consequent embryopathy. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Novel small-molecule AMPK activator orally exerts beneficial effects on diabetic db/db mice

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuan-Yuan; Yu, Li-Fang; Zhang, Li-Na; Qiu, Bei-Ying; Su, Ming-Bo; Wu, Fang; Chen, Da-Kai; Pang, Tao; Gu, Min; Zhang, Wei; Ma, Wei-Ping; Jiang, Hao-Wen; Li, Jing-Ya, E-mail: jyli@mail.shcnc.ac.cn; Nan, Fa-Jun, E-mail: fjnan@mail.shcnc.ac.cn; Li, Jia, E-mail: jli@mail.shcnc.ac.cn

    2013-12-01

    AMP-activated protein kinase (AMPK), which is a pivotal guardian of whole-body energy metabolism, has become an attractive therapeutic target for metabolic syndrome. Previously, using a homogeneous scintillation proximity assay, we identified the small-molecule AMPK activator C24 from an optimization based on the original allosteric activator PT1. In this paper, the AMPK activation mechanism of C24 and its potential beneficial effects on glucose and lipid metabolism on db/db mice were investigated. C24 allosterically stimulated inactive AMPK α subunit truncations and activated AMPK heterotrimers by antagonizing autoinhibition. In primary hepatocytes, C24 increased the phosphorylation of AMPK downstream target acetyl-CoA carboxylase dose-dependently without changing intracellular AMP/ATP ratio, indicating its allosteric activation in cells. Through activating AMPK, C24 decreased glucose output by down-regulating mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in primary hepatocytes. C24 also decreased the triglyceride and cholesterol contents in HepG2 cells. Due to its improved bioavailability, chronic oral treatment with multiple doses of C24 significantly reduced blood glucose and lipid levels in plasma, and improved the glucose tolerance of diabetic db/db mice. The hepatic transcriptional levels of PEPCK and G6Pase were reduced. These results demonstrate that this orally effective activator of AMPK represents a novel approach to the treatment of metabolic syndrome. - Highlights: • C24 activates AMPK through antagonizing autoinhibition within α subunit. • C24 activates AMPK in hepatocytes and decreases glucose output via AMPK. • C24 exerts beneficial effects on diabetic db/db mice. • C24 represents a novel therapeutic for treatment of metabolic syndrome.

  1. Novel small-molecule AMPK activator orally exerts beneficial effects on diabetic db/db mice

    International Nuclear Information System (INIS)

    Li, Yuan-Yuan; Yu, Li-Fang; Zhang, Li-Na; Qiu, Bei-Ying; Su, Ming-Bo; Wu, Fang; Chen, Da-Kai; Pang, Tao; Gu, Min; Zhang, Wei; Ma, Wei-Ping; Jiang, Hao-Wen; Li, Jing-Ya; Nan, Fa-Jun; Li, Jia

    2013-01-01

    AMP-activated protein kinase (AMPK), which is a pivotal guardian of whole-body energy metabolism, has become an attractive therapeutic target for metabolic syndrome. Previously, using a homogeneous scintillation proximity assay, we identified the small-molecule AMPK activator C24 from an optimization based on the original allosteric activator PT1. In this paper, the AMPK activation mechanism of C24 and its potential beneficial effects on glucose and lipid metabolism on db/db mice were investigated. C24 allosterically stimulated inactive AMPK α subunit truncations and activated AMPK heterotrimers by antagonizing autoinhibition. In primary hepatocytes, C24 increased the phosphorylation of AMPK downstream target acetyl-CoA carboxylase dose-dependently without changing intracellular AMP/ATP ratio, indicating its allosteric activation in cells. Through activating AMPK, C24 decreased glucose output by down-regulating mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in primary hepatocytes. C24 also decreased the triglyceride and cholesterol contents in HepG2 cells. Due to its improved bioavailability, chronic oral treatment with multiple doses of C24 significantly reduced blood glucose and lipid levels in plasma, and improved the glucose tolerance of diabetic db/db mice. The hepatic transcriptional levels of PEPCK and G6Pase were reduced. These results demonstrate that this orally effective activator of AMPK represents a novel approach to the treatment of metabolic syndrome. - Highlights: • C24 activates AMPK through antagonizing autoinhibition within α subunit. • C24 activates AMPK in hepatocytes and decreases glucose output via AMPK. • C24 exerts beneficial effects on diabetic db/db mice. • C24 represents a novel therapeutic for treatment of metabolic syndrome

  2. 5'-Monophosphate-activated protein kinase (AMPK improves autophagic activity in diabetes and diabetic complications

    Directory of Open Access Journals (Sweden)

    Fan Yao

    2016-01-01

    Full Text Available Diabetes mellitus (DM, an endocrine disorder, will be one of the leading causes of death world-wide in about two decades. Cellular injuries and disorders of energy metabolism are two key factors in the pathogenesis of diabetes, which also become the important causes for the process of diabetic complications. AMPK is a key enzyme in maintaining metabolic homeostasis and has been implicated in the activation of autophagy in distinct tissues. An increasing number of researchers have confirmed that autophagy is a potential factor to affect or induce diabetes and its complications nowadays, which could remove cytotoxic proteins and dysfunctional organelles. This review will summarize the regulation of autophagy and AMPK in diabetes and its complications, and explore how AMPK stimulates autophagy in different diabetic syndromes. A deeper understanding of the regulation and activity of AMPK in autophagy would enhance its development as a promising therapeutic target for diabetes treatment.

  3. Activation of skeletal muscle AMPK promotes glucose disposal and glucose lowering in non-human primates and mice

    DEFF Research Database (Denmark)

    Cokorinos, Emily C; Delmore, Jake; Reyes, Allan R

    2017-01-01

    The AMP-activated protein kinase (AMPK) is a potential therapeutic target for metabolic diseases based on its reported actions in the liver and skeletal muscle. We evaluated two distinct direct activators of AMPK: a non-selective activator of all AMPK complexes, PF-739, and an activator selective...

  4. Synthesis and biological evaluation of arctigenin ester and ether derivatives as activators of AMPK.

    Science.gov (United States)

    Shen, Sida; Zhuang, Jingjing; Chen, Yijia; Lei, Min; Chen, Jing; Shen, Xu; Hu, Lihong

    2013-07-01

    A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure-activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. AMPK Re-Activation Suppresses Hepatic Steatosis but its Downregulation Does Not Promote Fatty Liver Development

    Directory of Open Access Journals (Sweden)

    Nadia Boudaba

    2018-02-01

    Full Text Available Nonalcoholic fatty liver disease is a highly prevalent component of disorders associated with disrupted energy homeostasis. Although dysregulation of the energy sensor AMP-activated protein kinase (AMPK is viewed as a pathogenic factor in the development of fatty liver its role has not been directly demonstrated. Unexpectedly, we show here that liver-specific AMPK KO mice display normal hepatic lipid homeostasis and are not prone to fatty liver development, indicating that the decreases in AMPK activity associated with hepatic steatosis may be a consequence, rather than a cause, of changes in hepatic metabolism. In contrast, we found that pharmacological re-activation of downregulated AMPK in fatty liver is sufficient to normalize hepatic lipid content. Mechanistically, AMPK activation reduces hepatic triglyceride content both by inhibiting lipid synthesis and by stimulating fatty acid oxidation in an LKB1-dependent manner, through a transcription-independent mechanism. Furthermore, the effect of the antidiabetic drug metformin on lipogenesis inhibition and fatty acid oxidation stimulation was enhanced by combination treatment with small-molecule AMPK activators in primary hepatocytes from mice and humans. Overall, these results demonstrate that AMPK downregulation is not a triggering factor in fatty liver development but in contrast, establish the therapeutic impact of pharmacological AMPK re-activation in the treatment of fatty liver disease.

  6. AMP-Activated Kinase AMPK Is Expressed in Boar Spermatozoa and Regulates Motility

    Science.gov (United States)

    Hurtado de Llera, Ana; Martin-Hidalgo, David; Gil, María C.

    2012-01-01

    The main functions of spermatozoa required for fertilization are dependent on the energy status and metabolism. AMP-activated kinase, AMPK, acts a sensor and regulator of cell metabolism. As AMPK studies have been focused on somatic cells, our aim was to investigate the expression of AMPK protein in spermatozoa and its possible role in regulating motility. Spermatozoa from boar ejaculates were isolated and incubated under different conditions (38,5°C or 17°C, basal medium TBM or medium with Ca2+ and bicarbonate TCM, time from 1–24 hours) in presence or absence of AMPK inhibitor, compound C (CC, 30 µM). Western blotting reveals that AMPK is expressed in boar spermatozoa at relatively higher levels than in somatic cells. AMPK phosphorylation (activation) in spermatozoa is temperature-dependent, as it is undetectable at semen preservation temperature (17°C) and increases at 38,5°C in a time-dependent manner. AMPK phosphorylation is independent of the presence of Ca2+ and/or bicarbonate in the medium. We confirm that CC effectively blocks AMPK phosphorylation in boar spermatozoa. Analysis of spermatozoa motility by CASA shows that CC treatment either in TBM or in TCM causes a significant reduction of any spermatozoa motility parameter in a time-dependent manner. Thus, AMPK inhibition significantly decreases the percentages of motile and rapid spermatozoa, significantly reduces spermatozoa velocities VAP, VCL and affects other motility parameters and coefficients. CC treatment does not cause additional side effects in spermatozoa that might lead to a lower viability even at 24 h incubation. Our results show that AMPK is expressed in spermatozoa at high levels and is phosphorylated under physiological conditions. Moreover, our study suggests that AMPK regulates a relevant function of spermatozoa, motility, which is essential for their ultimate role of fertilization. PMID:22719961

  7. Mutant TDP-43 deregulates AMPK activation by PP2A in ALS models.

    Directory of Open Access Journals (Sweden)

    Nirma D Perera

    Full Text Available Bioenergetic abnormalities and metabolic dysfunctionoccur in amyotrophic lateral sclerosis (ALS patients and genetic mouse models. However, whether metabolic dysfunction occurs earlyin ALS pathophysiology linked to different ALS genes remains unclear.Here, we investigatedAMP-activated protein kinase (AMPK activation, which is a key enzyme induced by energy depletion and metabolic stress, inneuronal cells and mouse models expressing mutantsuperoxide dismutase 1 (SOD1or TAR DNA binding protein 43 (TDP-43 linked to ALS.AMPKphosphorylation was sharply increased in spinal cords of transgenic SOD1G93A mice at disease onset and accumulated incytoplasmic granules in motor neurons, but not in pre-symptomatic mice. AMPK phosphorylation also occurred in peripheraltissues, liver and kidney, in SOD1G93A mice at disease onset, demonstrating that AMPK activation occurs late and is not restricted to motor neurons. Conversely, AMPK activity was drastically diminished in spinal cords and brains of presymptomatic and symptomatictransgenic TDP-43A315T mice and motor neuronal cells expressing different TDP-43 mutants. We show that mutant TDP-43 induction of the AMPK phosphatase,protein phosphatase 2A (PP2A, is associated with AMPK inactivation in these ALS models. Furthermore, PP2A inhibition by okadaic acid reversed AMPK inactivation by mutant TDP-43 in neuronal cells. Our results suggest that mutant SOD1 and TDP-43 exert contrasting effects on AMPK activation which may reflect key differences in energy metabolism and neurodegeneration in spinal cords of SOD1G93A and TDP-43A315T mice. While AMPK activation in motor neurons correlateswith progressionin mutant SOD1-mediated disease, AMPK inactivation mediated by PP2Ais associated withmutant TDP-43-linked ALS.

  8. A Critical SUMO1 Modification of LKB1 Regulates AMPK Activity during Energy Stress

    KAUST Repository

    Ritho, Joan

    2015-07-23

    SUMOylation has been implicated in cellular stress adaptation, but its role in regulating liver kinase B1 (LKB1), a major upstream kinase of the energy sensor AMP-activated protein kinase (AMPK), is unknown. Here, we show that energy stress triggers an increase in SUMO1 modification of LKB1, despite a global reduction in both SUMO1 and SUMO2/3 conjugates. During metabolic stress, SUMO1 modification of LKB1 lysine 178 is essential in promoting its interaction with AMPK via a SUMO-interacting motif (SIM) essential for AMPK activation. The LKB1 K178R SUMO mutant had defective AMPK signaling and mitochondrial function, inducing death in energy-deprived cells. These results provide additional insight into how LKB1-AMPK signaling is regulated during energy stress, and they highlight the critical role of SUMOylation in maintaining the cell’s energy equilibrium.

  9. CB1 receptor mediates the effects of glucocorticoids on AMPK activity in the hypothalamus.

    Science.gov (United States)

    Scerif, Miski; Füzesi, Tamás; Thomas, Julia D; Kola, Blerina; Grossman, Ashley B; Fekete, Csaba; Korbonits, Márta

    2013-10-01

    AMP-activated protein kinase (AMPK), a regulator of cellular and systemic energy homeostasis, can be influenced by several hormones. Tissue-specific alteration of AMPK activity by glucocorticoids may explain the increase in appetite, the accumulation of lipids in adipose tissues, and the detrimental cardiac effects of Cushing's syndrome. Endocannabinoids are known to mediate the effects of various hormones and to influence AMPK activity. Cannabinoids have central orexigenic and direct peripheral metabolic effects via the cannabinoid receptor type 1 (CB1). In our preliminary experiments, WT mice received implants of a corticosterone-containing pellet to establish a mouse model of Cushing's syndrome. Subsequently, WT and Cb1 (Cnr1)-knockout (CB1-KO) littermates were treated with corticosterone and AMPK activity in the hypothalamus, various adipose tissues, liver and cardiac tissue was measured. Corticosterone-treated CB1-KO mice showed a lack of weight gain and of increase in hypothalamic and hepatic AMPK activity. In adipose tissues, baseline AMPK activity was higher in CB1-KO mice, but a glucocorticoid-induced drop was observed, similar to that observed in WT mice. Cardiac AMPK levels were reduced in CB1-KO mice, but while WT mice showed significantly reduced AMPK activity following glucocorticoid treatment, CB1-KO mice showed a paradoxical increase. Our findings indicate the importance of the CB1 receptor in the central orexigenic effect of glucocorticoid-induced activation of hypothalamic AMPK activity. In the periphery adipose tissues, changes may occur independently of the CB1 receptor, but the receptor appears to alter the responsiveness of the liver and myocardial tissues to glucocorticoids. In conclusion, our data suggest that an intact cannabinoid pathway is required for the full metabolic effects of chronic glucocorticoid excess.

  10. Natural AMPK Activators: An Alternative Approach for the Treatment and Management of Metabolic Syndrome.

    Science.gov (United States)

    Sharma, Hitender; Kumar, Sunil

    2017-01-01

    This review covers recent discoveries of phytoconstituents, herbal extracts and some semi-synthetic compounds for treating metabolic syndrome with AMPK activation as one of their mechanisms of action. Recent researches have demonstrated AMPK activation to ameliorate multiple components of metabolic syndrome by regulating a balance between anabolic and catabolic cellular reactions. The review attempts to delineate the AMPK activation by natural agents from the perspective of its functional consequences on enzymes, transcription factors and signaling molecules and also on other potential factors contributing in the amelioration of metabolic syndrome. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Activation of AMPK inhibits cholera toxin stimulated chloride secretion in human and murine intestine.

    Directory of Open Access Journals (Sweden)

    Ailín C Rogers

    Full Text Available Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR, is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK, can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK. In order to substantiate our findings on the whole tissue level, short-circuit current (SCC was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness.

  12. Interleukin-18 activates skeletal muscle AMPK and reduces weight gain and insulin resistance in mice.

    Science.gov (United States)

    Lindegaard, Birgitte; Matthews, Vance B; Brandt, Claus; Hojman, Pernille; Allen, Tamara L; Estevez, Emma; Watt, Matthew J; Bruce, Clinton R; Mortensen, Ole H; Syberg, Susanne; Rudnicka, Caroline; Abildgaard, Julie; Pilegaard, Henriette; Hidalgo, Juan; Ditlevsen, Susanne; Alsted, Thomas J; Madsen, Andreas N; Pedersen, Bente K; Febbraio, Mark A

    2013-09-01

    Circulating interleukin (IL)-18 is elevated in obesity, but paradoxically causes hypophagia. We hypothesized that IL-18 may attenuate high-fat diet (HFD)-induced insulin resistance by activating AMP-activated protein kinase (AMPK). We studied mice with a global deletion of the α-isoform of the IL-18 receptor (IL-18R(-/-)) fed a standard chow or HFD. We next performed gain-of-function experiments in skeletal muscle, in vitro, ex vivo, and in vivo. We show that IL-18 is implicated in metabolic homeostasis, inflammation, and insulin resistance via mechanisms involving the activation of AMPK in skeletal muscle. IL-18R(-/-) mice display increased weight gain, ectopic lipid deposition, inflammation, and reduced AMPK signaling in skeletal muscle. Treating myotubes or skeletal muscle strips with IL-18 activated AMPK and increased fat oxidation. Moreover, in vivo electroporation of IL-18 into skeletal muscle activated AMPK and concomitantly inhibited HFD-induced weight gain. In summary, IL-18 enhances AMPK signaling and lipid oxidation in skeletal muscle implicating IL-18 in metabolic homeostasis.

  13. AMPK and insulin action

    DEFF Research Database (Denmark)

    Frøsig, Christian; Jensen, Thomas Elbenhardt; Jeppesen, Jacob

    2013-01-01

    The 5'-AMP-activated protein kinase (AMPK) is considered "a metabolic master-switch" in skeletal muscle reducing ATP- consuming processes whilst stimulating ATP regeneration. Within recent years, AMPK has also been proposed as a potential target to attenuate insulin resistance, although the exact...... role of AMPK is not well understood. Here we hypothesized that mice lacking a2AMPK activity in muscle would be more susceptible to develop insulin resistance associated with ageing alone or in combination with high fat diet. Young (~4 month) or old (~18 month) wild type and muscle specific a2AMPK...... was not worsened in mice lacking functional a2AMPK in muscle. It is concluded that a2AMPK deficiency in mouse skeletal muscle does not cause muscle insulin resistance in young and old mice and does not exacerbate obesity-induced insulin resistance in old mice suggesting that decreased a2AMPK activity does...

  14. The AMP-Dependent Protein Kinase (AMPK Activator A-769662 Causes Arterial Relaxation by Reducing Cytosolic Free Calcium Independently of an Increase in AMPK Phosphorylation

    Directory of Open Access Journals (Sweden)

    Yi Huang

    2017-10-01

    Full Text Available Although recent studies reveal that activation of the metabolic and Ca2+ sensor AMPK strongly inhibits smooth muscle contraction, there is a paucity of information about the potential linkage between pharmacological AMPK activation and vascular smooth muscle (VSM contraction regulation. Our aim was to test the general hypothesis that the allosteric AMPK activator A-769662 causes VSM relaxation via inhibition of contractile protein activation, and to specifically determine which activation mechanism(s is(are affected. The ability of A-769662 to cause endothelium-independent relaxation of contractions induced by several contractile stimuli was examined in large and small musculocutaneous and visceral rabbit arteries. For comparison, the structurally dissimilar AMPK activators MET, SIM, and BBR were assessed. A-769662 displayed artery- and agonist-dependent differential inhibitory activities that depended on artery size and location. A-769662 did not increase AMPK-pT172 levels, but did increase phosphorylation of the downstream AMPK substrate, acetyl-CoA carboxylase (ACC. A-769662 did not inhibit basal phosphorylation levels of several contractile protein regulatory proteins, and did not alter the activation state of rhoA. A-769662 did not inhibit Ca2+- and GTPγS-induced contractions in β-escin-permeabilized muscle, suggesting that A-769662 must act by inhibiting Ca2+ signaling. In intact artery, A-769662 immediately reduced basal intracellular free calcium ([Ca2+]i, inhibited a stimulus-induced increase in [Ca2+]i, and inhibited a cyclopiazonic acid (CPA-induced contraction. MET increased AMPK-pT172, and caused neither inhibition of contraction nor inhibition of [Ca2+]i. Together, these data support the hypothesis that the differential inhibition of stimulus-induced arterial contractions by A-769662 was due to selective inhibition of a Ca2+ mobilization pathway, possibly involving CPA-dependent Ca2+ entry via an AMPK-independent pathway. That

  15. Use of metformin alone is not associated with survival outcomes of colorectal cancer cell but AMPK activator AICAR sensitizes anticancer effect of 5-fluorouracil through AMPK activation.

    Directory of Open Access Journals (Sweden)

    Xinbing Sui

    Full Text Available Colorectal cancer (CRC is still the third most common cancer and the second most common causes of cancer-related death around the world. Metformin, a biguanide, which is widely used for treating diabetes mellitus, has recently been shown to have a suppressive effect on CRC risk and mortality, but not all laboratory studies suggest that metformin has antineoplastic activity. Here, we investigated the effect of metformin and AMPK activator AICAR on CRC cells proliferation. As a result, metformin did not inhibit cell proliferation or induce apoptosis for CRC cell lines in vitro and in vivo. Different from metformin, AICAR emerged antitumor activity and sensitized anticancer effect of 5-FU on CRC cells in vitro and in vivo. In further analysis, we show that AMPK activation may be a key molecular mechanism for the additive effect of AICAR. Taken together, our results suggest that metformin has not antineoplastic activity for CRC cells as a single agent but AMPK activator AICAR can induce apoptosis and enhance the cytotoxic effect of 5-FU through AMPK activation.

  16. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    International Nuclear Information System (INIS)

    Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing; Gauthier, Marie-Soleil; Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper; Dole, William P.

    2011-01-01

    Highlights: → Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). → ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. → ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. → Exposure of human adipocytes to fatty acids and (TNFα) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and peroxisome proliferator-activated

  17. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Sandra C. [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States); Chau, Mary D.L.; Yang, Qing [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Gauthier, Marie-Soleil [Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02140 (United States); Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Dole, William P., E-mail: bill.dole@novartis.com [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-07-08

    Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

  18. Belinostat-induced apoptosis and growth inhibition in pancreatic cancer cells involve activation of TAK1-AMPK signaling axis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bing, E-mail: wangbin69@yahoo.com; Wang, Xin-bao; Chen, Li-yu; Huang, Ling; Dong, Rui-zen

    2013-07-19

    Highlights: •Belinostat activates AMPK in cultured pancreatic cancer cells. •Activation of AMPK is important for belinostat-induced cytotoxic effects. •ROS and TAK1 are involved in belinostat-induced AMPK activation. •AMPK activation mediates mTOR inhibition by belinostat. -- Abstract: Pancreatic cancer accounts for more than 250,000 deaths worldwide each year. Recent studies have shown that belinostat, a novel pan histone deacetylases inhibitor (HDACi) induces apoptosis and growth inhibition in pancreatic cancer cells. However, the underlying mechanisms are not fully understood. In the current study, we found that AMP-activated protein kinase (AMPK) activation was required for belinostat-induced apoptosis and anti-proliferation in PANC-1 pancreatic cancer cells. A significant AMPK activation was induced by belinostat in PANC-1 cells. Inhibition of AMPK by RNAi knockdown or dominant negative (DN) mutation significantly inhibited belinostat-induced apoptosis in PANC-1 cells. Reversely, AMPK activator AICAR and A-769662 exerted strong cytotoxicity in PANC-1 cells. Belinostat promoted reactive oxygen species (ROS) production in PANC-1 cells, increased ROS induced transforming growth factor-β-activating kinase 1 (TAK1)/AMPK association to activate AMPK. Meanwhile, anti-oxidants N-Acetyl-Cysteine (NAC) and MnTBAP as well as TAK1 shRNA knockdown suppressed belinostat-induced AMPK activation and PANC-1 cell apoptosis. In conclusion, we propose that belinostat-induced apoptosis and growth inhibition require the activation of ROS-TAK1-AMPK signaling axis in cultured pancreatic cancer cells.

  19. Rho-kinase inhibition ameliorates metabolic disorders through activation of AMPK pathway in mice.

    Directory of Open Access Journals (Sweden)

    Kazuki Noda

    Full Text Available BACKGROUND: Metabolic disorders, caused by excessive calorie intake and low physical activity, are important cardiovascular risk factors. Rho-kinase, an effector protein of the small GTP-binding protein RhoA, is an important cardiovascular therapeutic target and its activity is increased in patients with metabolic syndrome. We aimed to examine whether Rho-kinase inhibition improves high-fat diet (HFD-induced metabolic disorders, and if so, to elucidate the involvement of AMP-activated kinase (AMPK, a key molecule of metabolic conditions. METHODS AND RESULTS: Mice were fed a high-fat diet, which induced metabolic phenotypes, such as obesity, hypercholesterolemia and glucose intolerance. These phenotypes are suppressed by treatment with selective Rho-kinase inhibitor, associated with increased whole body O2 consumption and AMPK activation in the skeletal muscle and liver. Moreover, Rho-kinase inhibition increased mRNA expression of the molecules linked to fatty acid oxidation, mitochondrial energy production and glucose metabolism, all of which are known as targets of AMPK in those tissues. In systemic overexpression of dominant-negative Rho-kinase mice, body weight, serum lipid levels and glucose metabolism were improved compared with littermate control mice. Furthermore, in AMPKα2-deficient mice, the beneficial effects of fasudil, a Rho-kinase inhibitor, on body weight, hypercholesterolemia, mRNA expression of the AMPK targets and increase of whole body O2 consumption were absent, whereas glucose metabolism was restored by fasudil to the level in wild-type mice. In cultured mouse myocytes, pharmacological and genetic inhibition of Rho-kinase increased AMPK activity through liver kinase b1 (LKB1, with up-regulation of its targets, which effects were abolished by an AMPK inhibitor, compound C. CONCLUSIONS: These results indicate that Rho-kinase inhibition ameliorates metabolic disorders through activation of the LKB1/AMPK pathway, suggesting that

  20. Glutaredoxins concomitant with optimal ROS activate AMPK through S-glutathionylation to improve glucose metabolism in type 2 diabetes.

    Science.gov (United States)

    Dong, Kelei; Wu, Meiling; Liu, Xiaomin; Huang, Yanjie; Zhang, Dongyang; Wang, Yiting; Yan, Liang-Jun; Shi, Dongyun

    2016-12-01

    AMPK dysregulation contributes to the onset and development of type 2 diabetes (T2DM). AMPK is known to be activated by reactive oxygen species (ROS) and antioxidant interference. However the mechanism by which redox state mediates such contradictory result remains largely unknown. Here we used streptozotocin-high fat diet (STZ-HFD) induced-type 2 diabetic rats and cells lines (L02 and HEK 293) to explore the mechanism of redox-mediated AMPK activation. We show glutaredoxins (Grxs) concomitant with optimal ROS act as an essential mediator for AMPK activation. ROS level results in different mechanisms for AMPK activation. Under low ROS microenvironment, Grxs-mediated S-glutathionylation on AMPK-α catalytic subunit activates AMPK to improve glucose transportation and degradation while inhibiting glycogen synthesis and keeping redox balance. While, under high ROS microenvironment, AMPK is activated by an AMP-dependent mechanism, however sustained high level ROS also causes loss of AMPK protein. This finding provides evidence for a new approach to diabetes treatment by individual doses of ROS or antioxidant calibrated against the actual redox level in vivo. Moreover, the novel function of Grxs in promoting glucose metabolism may provide new target for T2DM treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Activation of AMPK by OSU53 protects spinal cord neurons from oxidative stress.

    Science.gov (United States)

    Xu, Jun; Wu, Liang; Zhang, Yiming; Gu, Huijie; Huang, Zhongyue; Zhou, Kaifeng; Yin, Xiaofan

    2017-12-22

    The present study tested the potential effect of OSU53, a novel AMPK activator, against hydrogen peroxide (H2O2)-induced spinal cord neuron damages. Treatment with OSU53 attenuated H2O2-induced death and apoptosis of primary murine spinal cord neurons. OSU53 activated AMPK signaling, which is required for its actions in spinal cord neurons. The AMPK inhibitor Compound C or AMPKα1 siRNA almost abolished OSU53-mediated neuroprotection against H2O2. On the other hand, sustained-activation of AMPK by introducing the constitutive-active AMPKα1 mimicked OSU53's actions, and protected spinal cord neurons from oxidative stress. OSU53 significantly attenuated H2O2-induced reactive oxygen species production, lipid peroxidation and DNA damages in spinal cord neurons. Additionally, OSU53 increased NADPH content and heme oxygenase-1 mRNA expression in H2O2-treated spinal cord neurons. Together, we indicate that targeted-activation of AMPK by OSU53 protects spinal cord neurons from oxidative stress.

  2. Dibenzoylmethane exerts metabolic activity through regulation of AMP-activated protein kinase (AMPK-mediated glucose uptake and adipogenesis pathways.

    Directory of Open Access Journals (Sweden)

    Nami Kim

    Full Text Available Dibenzoylmethane (DBM has been shown to exert a variety of beneficial effects on human health. However, the mechanism of action is poorly understood. In this study, DBM increased phosphorylation of AMP-activated protein kinase (AMPK and stimulated glucose uptake in a skeletal muscle cell line. Both knockdown of AMPK with siRNA and inhibition with AMPK inhibitor blocked DBM-induced glucose uptake. DBM increased the concentration of intracellular calcium and glucose uptake due to DBM was abolished by STO-609 (a calcium/calmodulin-dependent protein kinase inhibitor. DBM stimulated phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK, which was blocked by pretreatment with compound C, an AMPK inhibitor. The expression of glucose transporter type 4 (GLUT4 was increased by DBM. The translocation of GLUT4 to the plasma membrane was also increased by DBM in AMPK dependently. In addition, DBM suppressed weight gain and prevented fat accumulation in the liver and abdomen in mice fed a high-fat diet. In pre-adipocyte cells, DBM decreased the activity of acetyl-CoA carboxylase (ACC, the rate-limiting enzyme of fatty acid synthesis. Expression of the adipogenic gene, fatty acid synthase (FAS, was suppressed by DBM in an AMPK-dependent manner. These results showed that the beneficial metabolic effects of DBM might be due to regulation of glucose uptake via AMPK in skeletal muscle and inhibition of adipogenesis in pre-adipocytes.

  3. Novel direct AMPK activator suppresses non-small cell lung cancer through inhibition of lipid metabolism

    Science.gov (United States)

    Chen, Xi; Xie, Chun; Fan, Xing-Xing; Jiang, Ze-Bo; Wong, Vincent Kam-Wai; Xu, Jia-Hui; Yao, Xiao-Jun; Liu, Liang; Leung, Elaine Lai-Han

    2017-01-01

    Drug resistance is becoming an obstacle in anti-cancer therapies. For target-based therapy of lung cancer, gefitinib, as the first generation of tyrosine kinase inhibitors (TKIs), demonstrated good initial response to the non-small cell lung cancer (NSCLC) patients whom harbors epidermal growth factor receptor (EGFR) mutation. However, within one year, additional EGFR mutation occurred, leading to eventual gefitinib-resistance. Therefore, it is urgently to discover novel effective small molecule inhibitors for those patients. Abnormal energy metabolism is accepted as new cancer hallmark. Recently, a metabolism rate-limiting enzyme 5’-adenosine menophosphate-activated protein kinase (AMPK) has become a promising anti-cancer target. In this study, we have identified a novel direct AMPK agonist, D561-0775 from a compound library by using molecular docking screening technique. We demonstrated that D561-0775 exhibited significant inhibitory effect on gefitinib-resistant NSCLC cell lines but less cytotoxicity on normal cells. Furthermore, D561-0775 demonstrated a remarkable in vitro AMPK enzyme activation effect. Taken together, D561-0775 showed potential anti-cancer activity via inducing apoptosis, cell cycle arrest, suppressing glycolysis and cholesterol synthesis after activation of AMPK in gefitinib-resistant H1975 cells. D561-0775 has provided a new chemical structure that could be developed as cancer drug for gefitinib-resistant NSCLC patients through inhibition lipid metabolism by directly targeting at AMPK directly. PMID:29221189

  4. Metformin and salicylate synergistically activate liver AMPK, inhibit lipogenesis and improve insulin sensitivity

    Science.gov (United States)

    Ford, Rebecca J.; Fullerton, Morgan D.; Pinkosky, Stephen L.; Day, Emily A.; Scott, John W.; Oakhill, Jonathan S.; Bujak, Adam L.; Smith, Brennan K.; Crane, Justin D.; Blumer, Regje M.; Marcinko, Katarina; Kemp, Bruce E.; Gerstein, Hertzel C.; Steinberg, Gregory R.

    2017-01-01

    Metformin is the mainstay therapy for type 2 diabetes (T2D) and many patients also take salicylate-based drugs [i.e., aspirin (ASA)] for cardioprotection. Metformin and salicylate both increase AMP-activated protein kinase (AMPK) activity but by distinct mechanisms, with metformin altering cellular adenylate charge (increasing AMP) and salicylate interacting directly at the AMPK β1 drug-binding site. AMPK activation by both drugs results in phosphorylation of ACC (acetyl-CoA carboxylase; P-ACC) and inhibition of acetyl-CoA carboxylase (ACC), the rate limiting enzyme controlling fatty acid synthesis (lipogenesis). We find doses of metformin and salicylate used clinically synergistically activate AMPK in vitro and in vivo, resulting in reduced liver lipogenesis, lower liver lipid levels and improved insulin sensitivity in mice. Synergism occurs in cell-free assays and is specific for the AMPK β1 subunit. These effects are also observed in primary human hepatocytes and patients with dysglycaemia exhibit additional improvements in a marker of insulin resistance (proinsulin) when treated with ASA and metformin compared with either drug alone. These data indicate that metformin–salicylate combination therapy may be efficacious for the treatment of non-alcoholic fatty liver disease (NAFLD) and T2D. PMID:25742316

  5. AMPK Negatively Regulates Peripheral Myelination via Activation of c-Jun.

    Science.gov (United States)

    Liu, Xiaoyu; Peng, Su; Zhao, Yahong; Zhao, Tingting; Wang, Meihong; Luo, Lan; Yang, Yumin; Sun, Cheng

    2017-07-01

    The process of Schwann cells (SCs) forming a sheath around axons is termed as myelination, which plays a pivotal role for proper physiological function in the peripheral nervous system (PNS). The molecular mechanisms regulating SC myelination in the PNS remain to be elucidated. Here, we show that AMP-activated protein kinase (AMPK) in sciatic nerves was gradually decreased during the PNS myelination process. Pharmacological interventions showed that activation of AMPK by AICAR attenuated myelin gene expression in SCs, whereas inhibition of AMPK by Compound C (ComC) or AMPKα1 knockdown stimulated myelin gene expression. Following experiments revealed that c-Jun, a negative modulator of PNS myelination, was activated by AMPK in SCs. The application of ComC in newborn rats markedly downregulated c-Jun expression in sciatic nerves. The lipid and protein synthesis in sciatic nerves was greatly potentiated by ComC. As a consequence, myelin gene expression in sciatic nerves, as well as myelin sheath thickness, were promoted in the ComC-treated rats. All together, our data identify that AMPK is an important negative regulator of Schwann cell myelination in the PNS, and this regulation role may rely on c-Jun activation.

  6. Zanthoxylum alkylamides activate phosphorylated AMPK and ameliorate glycolipid metabolism in the streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Ren, Tingyuan; Zhu, Yuping; Kan, Jianquan

    2017-01-01

    This study aimed to evaluate the effects of Zanthoxylum alkylamides on the glycolipid metabolism of rats with streptozotocin (STZ)-induced diabetes. Diabetic rats were given daily oral treatments of 2, 4, or 8 mg/kg bw alkylamides for 28 days. Alkylamides significantly decreased fasting blood glucose and fructosamine content, as well as relieved organ enlargement caused by diabetes. The serum and liver triglyceride, malondialdehyde, and free fatty-acid contents of rats with STZ-induced diabetes were significantly reduced. Total cholesterol in the liver also significantly decreased. Quantitative polymerase chain reaction (Q-PCR) and Western blot detected insignificantly increased (P > 0.05) mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK) in the skeletal muscle of diabetic rats. However, AMPK and p-AMPK (Thr172) protein expression levels significantly increased. The mRNA and protein expression levels of silencing information regulator 1 significantly increased. The mRNA expression levels of acetyl-CoA-carboxylase (ACC) and protein p-ACC (Ser79) also increased. The mRNA and protein expression levels of glucose transporter type 4 (GLUT4) were significantly upregulated in the skeletal muscle cell membranes of diabetic rats. Results indicated that alkylamides activated the AMPK-signaling pathway. Thus, inhibiting ACC activity reduced fatty-acid synthesis. The rapid translocation of GLUT4 mediated increased glucose transport rate and reduced blood glucose. Therefore, alkylamides can ameliorate glucose and lipid metabolism disorders in diabetic rats by activating the AMPK pathway.

  7. Palmitoleic Acid Improves Metabolic Functions in Fatty Liver by PPARα-Dependent AMPK Activation.

    Science.gov (United States)

    de Souza, Camila O; Teixeira, Alexandre A S; Biondo, Luana A; Lima Junior, Edson A; Batatinha, Helena A P; Rosa Neto, Jose C

    2017-08-01

    Palmitoleic acid, since described as lipokine, increases glucose uptake by modulation of 5'AMP-activated protein kinase (AMPK), as well as increasing lipolysis by activation of peroxisome proliferator-activated receptor-α (PPARα), in adipose tissue. However, in liver, the effects of palmitoleic acid on glucose metabolism and the role of PPARα remain unknown. To investigate whether palmitoleic acid improved the hepatic insulin sensitivity of obese mice. C57BL6 and PPARα knockout (KO) mice were fed for 12 weeks with a standard diet (SD) or high-fat diet (HF), and in the last 2 weeks were treated with oleic or palmitoleic acid. Palmitoleic acid promoted a faster uptake of glucose in the body, associated with higher insulin concentration; however, even when stimulated with insulin, palmitoleic acid did not modulate the insulin pathway (AKT, IRS). Palmitoleic acid increased the phosphorylation of AMPK, upregulated glucokinase and downregulated SREBP-1. Regarding AMPK downstream, palmitoleic acid increased the production of FGF-21 and stimulated the expression of PPARα. Palmitoleic acid treatment did not increase AMPK phosphorylation, modulate glucokinase or increase FGF-21 in liver of PPARα KO mice. In mice fed with a high-fat diet, palmitoleic acid supplementation stimulated the uptake of glucose in liver through activation of AMPK and FGF-21, dependent on PPARα. J. Cell. Physiol. 232: 2168-2177, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Kaempferol induces autophagic cell death of hepatocellular carcinoma cells via activating AMPK signaling.

    Science.gov (United States)

    Han, Bing; Yu, Yi-Qun; Yang, Qi-Lian; Shen, Chun-Ying; Wang, Xiao-Juan

    2017-10-17

    In the present study, we demonstrate that Kaempferol inhibited survival and proliferation of established human hepatocellular carcinoma (HCC) cell lines (HepG2, Huh-7, BEL7402, and SMMC) and primary human HCC cells. Kaempferol treatment in HCC cells induced profound AMP-activated protein kinase (AMPK) activation, which led to Ulk1 phosphorylation, mTOR complex 1 inhibition and cell autophagy. Autophagy induction was reflected by Beclin-1/autophagy gene 5 upregulation and p62 degradation as well as light chain 3B (LC3B)-I to LC3B-II conversion and LC3B puncta formation. Inhibition of AMPK, via AMPKα1 shRNA or dominant negative mutation, reversed above signaling changes. AMPK inhibition also largely inhibited Kaempferol-induced cytotoxicity in HCC cells. Autophagy inhibition, by 3-methyaldenine or Beclin-1 shRNA, also protected HCC cells from Kaempferol. Kaempferol downregulated melanoma antigen 6, the AMPK ubiquitin ligase, causing AMPKα1 stabilization and accumulation. We conclude that Kaempferol inhibits human HCC cells via activating AMPK signaling.

  9. Rhodiola crenulata extract suppresses hepatic gluconeogenesis via activation of the AMPK pathway.

    Science.gov (United States)

    Lee, Shih-Yu; Lai, Feng-Yi; Shi, Li-Shian; Chou, Yu-Ching; Yen, I-Chuan; Chang, Tsu-Chung

    2015-04-15

    Rhodiola, a popular herb, has been used for treating high altitude sicknesses, depression, fatigue, and diabetes. However, the detailed mechanisms by which Rhodiola crenulata functions in the liver need further clarification. The current study was designed to examine the effects of Rhodiola crenulata root extract (RCE) on hepatic glucose production. Human hepatoma HepG2 cells were treated with RCE for 6 h. Glucose production, the expression level of p-AMPK, and the expression of key gluconeogenic genes were measured. The effects of RCE were also studied in Sprague-Dawley (SD) rats. The efficacy and underlying mechanism of RCE in the liver were examined. RCE significantly suppressed glucose production and gluconeogenic gene expression in HepG2 cells while activating the AMPK signaling pathway. Interestingly, RCE-suppressed hepatic gluconeogenesis was eliminated by an AMPK-specific inhibitor, but not by the PI3K/AKT-specific inhibitor. In addition, oral administration of RCE significantly increased phosphorylated AMPK levels and inhibited gluconeogenic gene expression in the rat liver. Furthermore, RCE treatment also decreased plasma glucose concentration in rats. We present in vitro and in vivo evidence that RCE might exert the glucose-lowering effect partly by inhibiting hepatic gluconeogenesis through activating the AMPK signaling pathway. These findings provide evidence that Rhodiola crenulata may be helpful for the management of type II diabetes. Copyright © 2015 Elsevier GmbH. All rights reserved.

  10. Swift Quantification of Fenofibrate and Tiemonium methylsulfate Active Ingredients in Solid Drugs Using Particle Induced X-Ray Emission

    International Nuclear Information System (INIS)

    Bejjani, A.; Nsouli, B.; Zahraman, K.; Assi, S.; Younes, Gh.; Yazbi, F.

    2011-01-01

    The quantification of active ingredients (AI) in drugs is a crucial and important step in the drug quality control process. This is usually performed by using wet chemical techniques like LC-MS, UV spectrophotometry and other appropriate organic analytical methods. However, if the active ingredient contains specific heteroatoms (F, S, Cl), elemental IBA like PIXE and PIGE techniques, using small tandem accelerator of 1-2 MV, can be explored for molecular quantification. IBA techniques permit the analysis of the sample under solid form, without any laborious sample preparations. In this work, we demonstrate the ability of the Thick Target PIXE technique for rapid and accurate quantification of both low and high concentrations of active ingredients in different commercial drugs. Fenofibrate, a chlorinated active ingredient, is present in high amounts in two different commercial drugs, its quantification was done using the relative approach to an external standard. On the other hand, Tiemonium methylsulfate which exists in relatively low amount in commercial drugs, its quantification was done using GUPIX simulation code (absolute quantification). The experimental aspects related to the quantification validity (use of external standards, absolute quantification, matrix effect,...) are presented and discussed. (author)

  11. Selective Activation of AMPK β1-Containing Isoforms Improves Kidney Function in a Rat Model of Diabetic Nephropathy.

    Science.gov (United States)

    Salatto, Christopher T; Miller, Russell A; Cameron, Kimberly O; Cokorinos, Emily; Reyes, Allan; Ward, Jessica; Calabrese, Matthew F; Kurumbail, Ravi G; Rajamohan, Francis; Kalgutkar, Amit S; Tess, David A; Shavnya, Andre; Genung, Nathan E; Edmonds, David J; Jatkar, Aditi; Maciejewski, Benjamin S; Amaro, Marina; Gandhok, Harmeet; Monetti, Mara; Cialdea, Katherine; Bollinger, Eliza; Kreeger, John M; Coskran, Timothy M; Opsahl, Alan C; Boucher, Germaine G; Birnbaum, Morris J; DaSilva-Jardine, Paul; Rolph, Tim

    2017-05-01

    Diabetic nephropathy remains an area of high unmet medical need, with current therapies that slow down, but do not prevent, the progression of disease. A reduced phosphorylation state of adenosine monophosphate-activated protein kinase (AMPK) has been correlated with diminished kidney function in both humans and animal models of renal disease. Here, we describe the identification of novel, potent, small molecule activators of AMPK that selectively activate AMPK heterotrimers containing the β 1 subunit. After confirming that human and rodent kidney predominately express AMPK β 1, we explore the effects of pharmacological activation of AMPK in the ZSF1 rat model of diabetic nephropathy. Chronic administration of these direct activators elevates the phosphorylation of AMPK in the kidney, without impacting blood glucose levels, and reduces the progression of proteinuria to a greater degree than the current standard of care, angiotensin-converting enzyme inhibitor ramipril. Further analyses of urine biomarkers and kidney tissue gene expression reveal AMPK activation leads to the modulation of multiple pathways implicated in kidney injury, including cellular hypertrophy, fibrosis, and oxidative stress. These results support the need for further investigation into the potential beneficial effects of AMPK activation in kidney disease. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Activation of Skeletal Muscle AMPK Promotes Glucose Disposal and Glucose Lowering in Non-human Primates and Mice.

    Science.gov (United States)

    Cokorinos, Emily C; Delmore, Jake; Reyes, Allan R; Albuquerque, Bina; Kjøbsted, Rasmus; Jørgensen, Nicolas O; Tran, Jean-Luc; Jatkar, Aditi; Cialdea, Katherine; Esquejo, Ryan M; Meissen, John; Calabrese, Matthew F; Cordes, Jason; Moccia, Robert; Tess, David; Salatto, Christopher T; Coskran, Timothy M; Opsahl, Alan C; Flynn, Declan; Blatnik, Matthew; Li, Wenlin; Kindt, Erick; Foretz, Marc; Viollet, Benoit; Ward, Jessica; Kurumbail, Ravi G; Kalgutkar, Amit S; Wojtaszewski, Jørgen F P; Cameron, Kimberly O; Miller, Russell A

    2017-05-02

    The AMP-activated protein kinase (AMPK) is a potential therapeutic target for metabolic diseases based on its reported actions in the liver and skeletal muscle. We evaluated two distinct direct activators of AMPK: a non-selective activator of all AMPK complexes, PF-739, and an activator selective for AMPK β1-containing complexes, PF-249. In cells and animals, both compounds were effective at activating AMPK in hepatocytes, but only PF-739 was capable of activating AMPK in skeletal muscle. In diabetic mice, PF-739, but not PF-249, caused a rapid lowering of plasma glucose levels that was diminished in the absence of skeletal muscle, but not liver, AMPK heterotrimers and was the result of an increase in systemic glucose disposal with no impact on hepatic glucose production. Studies of PF-739 in cynomolgus monkeys confirmed translation of the glucose lowering and established activation of AMPK in skeletal muscle as a potential therapeutic approach to treat diabetic patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. AMPK activation: Role in the signaling pathways of neuroinflammation and neurodegeneration.

    Science.gov (United States)

    Peixoto, Christina Alves; Oliveira, Wilma Helena de; Araújo, Shyrlene Meiry da Racho; Nunes, Ana Karolina Santana

    2017-12-01

    Adenosine monophosphate-activated protein kinase (AMPK) is an evolutionarily conserved sensor of cellular energy status and has been reported to be involved in chronic inflammatory disorders. AMPK is expressed in immune cells, such as dendritic cells, macrophages, lymphocytes and neutrophils, and is an important regulator of inflammatory responses through the regulation of complex signaling networks in part by inhibiting downstream cascade pathways, such as nuclear factor kB, which is a key regulator of innate immunity and inflammation, as well as acting as a negative regulator of toll-like receptors. Recent data suggest that AMPK dysregulation may participate in neurodegenerative diseases, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and neuropathies. However, there are conflicting reports on the benefits or detrimental effects of AMPK in distinct pathological conditions. This paper offers a review of the recent literature on the pharmacological modulation of the AMPK system as a potential molecular target in the management of neurodegenerative diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Quercetin enhances hypoxia-mediated apoptosis via direct inhibition of AMPK activity in HCT116 colon cancer.

    Science.gov (United States)

    Kim, Hak-Su; Wannatung, Tirawat; Lee, Sooho; Yang, Woo Kyeom; Chung, Sung Hyun; Lim, Jong-Seok; Choe, Wonchae; Kang, Insug; Kim, Sung-Soo; Ha, Joohun

    2012-09-01

    Tumor hypoxia is considered the best validated target in clinical oncology because of its significant contribution to chemotherapy failure and drug resistance. As an approach to target hypoxia, we assessed the potential of quercetin, a flavonoid widely distributed in plants, as a anticancer agent under hypoxic conditions and examined its pharmacological mechanisms by primarily focusing on the role of AMP-activated protein kinase (AMPK). Quercetin significantly attenuated tumor growth in an HCT116 cancer xenograft in vivo model with a substantial reduction of AMPK activity. In a cell culture system, quercetin more dramatically induced apoptosis of HCT116 cancer cells under hypoxic conditions than normoxic conditions, and this was tightly associated with inhibition of hypoxia-induced AMPK activity. An in vitro kinase assay demonstrated that quercetin directly inhibits AMPK activity. Inhibition of AMPK by expressing a dominant-negative form resulted in an increase of apoptosis under hypoxia, and a constitutively active form of AMPK effectively blocked quercetin-induced apoptosis under hypoxia. Collectively, our data suggest that quercetin directly inhibits hypoxia-induced AMPK, which plays a protective role against hypoxia. Quercetin also reduced the activity of hypoxia-inducible factor-1 (HIF-1), a major transcription factor for adaptive cellular response to hypoxia. Moreover, quercetin sensitized HCT116 cancer cells to the anticancer drugs cisplatin and etoposide under hypoxic conditions. Our findings suggest that AMPK may serve as a novel target for overcoming tumor hypoxia-associated negative aspects.

  15. Higher skeletal muscle alpha2AMPK activation and lower energy charge and fat oxidation in men than in women during submaximal exercise

    DEFF Research Database (Denmark)

    Roepstorff, Carsten; Thiele, Maja; Hillig, Thore

    2006-01-01

    5'AMP-activated protein kinase (AMPK) is an energy sensor activated by perturbed cellular energy status such as during muscle contraction. Activated AMPK is thought to regulate several key metabolic pathways. We used sex comparison to investigate whether AMPK signalling in skeletal muscle regulat...... fat oxidation during exercise....

  16. Interleukin-18 activates skeletal muscle AMPK and reduces weight gain and insulin resistance in mice

    DEFF Research Database (Denmark)

    Madsen, Birgitte Lindegaard; Matthews, Vance B; Brandt, Claus

    2013-01-01

    Circulating interleukin (IL)-18 is elevated in obesity, but paradoxically causes hypophagia. We hypothesized that IL-18 may attenuate high fat diet induced insulin resistance by activating AMP activated protein kinase (AMPK). We studied mice with a global deletion of the α isoform of the IL-18...

  17. A novel AMPK activator hernandezine inhibits LPS-induced TNFα production.

    Science.gov (United States)

    Li, Ping; Li, Xiaofang; Wu, Yonghong; Li, Manxiang; Wang, Xiaochuang

    2017-09-15

    Here, we found that hernandezine, a novel AMPK activator, inhibited LPS-induced TNFα expression/production in human macrophage cells (THP-1 and U937 lines). Activation of AMPK is required for hernandezine-induced anti-LPS response. AMPKα shRNA or dominant negative mutation (T172A) blocked hernandezine-induced AMPK activation, which almost completely reversed anti-LPS activity by hernandezine. Exogenous expression of the constitutively activate AMPKα (T172D, caAMPKα) also suppressed TNFα production by LPS. Remarkably, hernandezine was unable to further inhibit LPS-mediated TNFα production in caAMPKα-expressing cells. Hernandezine inhibited LPS-induced reactive oxygen species (ROS) production and nuclear factor kappa B (NFκB) activation. Treatment of hernandezine in ex-vivo cultured primary human peripheral blood mononuclear cells (PBMCs) also largely attenuated LPS-induced TNFα production. Together, we conclude that AMPK activation by hernandezine inhibits LPS-induced TNFα production in macrophages/monocytes.

  18. Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle

    DEFF Research Database (Denmark)

    Bultot, Laurent; Jensen, Thomas Elbenhardt; Lai, Yu-Chiang

    2016-01-01

    AMP-activated protein kinase (AMPK) plays diverse roles and coordinates complex metabolic pathways for maintenance of energy homeostasis. This could be explained by the fact that AMPK exists as multiple heterotrimer complexes comprising a catalytic α-subunit (α1 and α2) and regulatory β (β1 and β...

  19. Specific Sirt1 Activator-mediated Improvement in Glucose Homeostasis Requires Sirt1-Independent Activation of AMPK

    Directory of Open Access Journals (Sweden)

    Sung-Jun Park

    2017-04-01

    Full Text Available The specific Sirt1 activator SRT1720 increases mitochondrial function in skeletal muscle, presumably by activating Sirt1. However, Sirt1 gain of function does not increase mitochondrial function, which raises a question about the central role of Sirt1 in SRT1720 action. Moreover, it is believed that the metabolic effects of SRT1720 occur independently of AMP-activated protein kinase (AMPK, an important metabolic regulator that increases mitochondrial function. Here, we show that SRT1720 activates AMPK in a Sirt1-independent manner and SRT1720 activates AMPK by inhibiting a cAMP degrading phosphodiesterase (PDE in a competitive manner. Inhibiting the cAMP effector protein Epac prevents SRT1720 from activating AMPK or Sirt1 in myotubes. Moreover, SRT1720 does not increase mitochondrial function or improve glucose tolerance in AMPKα2 knockout mice. Interestingly, weight loss induced by SRT1720 is not sufficient to improve glucose tolerance. Therefore, contrary to current belief, the metabolic effects produced by SRT1720 require AMPK, which can be activated independently of Sirt1.

  20. Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Wei, E-mail: weiming@xiyi.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Department of Pharmacology, Xi’an Medical University, Xi’an 710021 (China); Lu, Gan, E-mail: leonming99@163.com [Department of Gynecology of Shaanxi Provincial People’s Hospital, Xi’an, 710068 (China); Xin, Sha, E-mail: 248967979@qq.com [Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an 710032 (China); Huanyu, Lu, E-mail: 2366927258@qq.com [Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi’an 710032 (China); Yinghao, Jiang, E-mail: jiangyh@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Xiaoying, Lei, E-mail: leixiaoy@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Chengming, Xu, E-mail: chengmingxu@yeah.net [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Banjun, Ruan, E-mail: running@163.com [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Li, Wang, E-mail: wanglifw@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); and others

    2016-08-05

    Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

  1. Lipoprotein internalisation induced by oncogenic AMPK activation is essential to maintain glioblastoma cell growth.

    Science.gov (United States)

    Ríos, M; Foretz, M; Viollet, B; Prieto, A; Fraga, M; García-Caballero, T; Costoya, J A; Señarís, R

    2014-12-01

    Metabolic adaptations are essential during tumour growth to maintain the high proliferation levels exhibited by cancer cells. In this study, we examined the transformations that occurred in the lipid metabolism in astrocytic tumours, and the possible role of the fuel-sensing enzyme AMPK. Metabolic targets might help design new and effective drugs for cancer. To accomplish this objective, we studied both mice and human astrocytic tumours. We first used a mouse model of astrocytoma driven by oncogenic H-RasV12 and/or with PTEN deletion based on the common constitutive activation of the Raf/MEK/ERK and PI3K/AKT cascades in human astrocytomas. We then confirmed the results in human glioblastoma cell lines and in glioblastoma tissue samples from patients. We show that the high levels of activated AMPK, observed in astrocytic tumours, increase extracellular lipid internalisation and reduce energy expenditure by inhibiting 'de novo' fatty acid (FA) synthesis, which allows tumour cells to obtain building blocks and energy to be able to create new organelles and new cells. Our findings demonstrate that AMPK plays a crucial role in glioblastoma cell growth and suggest that blocking lipoprotein receptors could potentially be used as a plausible therapeutic approach for these and other type of tumours with high levels of AMPK. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

    International Nuclear Information System (INIS)

    Ming, Wei; Lu, Gan; Xin, Sha; Huanyu, Lu; Yinghao, Jiang; Xiaoying, Lei; Chengming, Xu; Banjun, Ruan; Li, Wang

    2016-01-01

    Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

  3. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function.

    Directory of Open Access Journals (Sweden)

    Sun Woo Sophie Kang

    Full Text Available Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK. When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury.

  4. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function

    Science.gov (United States)

    Taniane, Caitlin; Farrell, Geoffrey; Arias, Irwin M.; Lippincott-Schwartz, Jennifer; Fu, Dong

    2016-01-01

    Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK). When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury. PMID:27792760

  5. Activation of AMPK in human fetal membranes alleviates infection-induced expression of pro-inflammatory and pro-labour mediators.

    Science.gov (United States)

    Lim, R; Barker, G; Lappas, M

    2015-04-01

    In non-gestational tissues, the activation of adenosine monophosphate (AMP)-activated kinase (AMPK) is associated with potent anti-inflammatory actions. Infection and/or inflammation, by stimulating pro-inflammatory cytokines and matrix metalloproteinase (MMP)-9, play a central role in the rupture of fetal membranes. However, no studies have examined the role of AMPK in human labour. Fetal membranes, from term and preterm, were obtained from non-labouring and labouring women, and after preterm pre-labour rupture of membranes (PPROM). AMPK activity was assessed by Western blotting of phosphorylated AMPK expression. To determine the effect of AMPK activators on pro-inflammatory cytokines, fetal membranes were pre-treated with AMPK activators then stimulated with bacterial products LPS and flagellin or viral dsDNA analogue poly(I:C). Primary amnion cells were used to determine the effect of AMPK activators on IL-1β-stimulated MMP-9 expression. AMPK activity was decreased with term labour. There was no effect of preterm labour. AMPK activity was also decreased in preterm fetal membranes, in the absence of labour, with PROM compared to intact membranes. AMPK activators AICAR, phenformin and A769662 significantly decreased IL-6 and IL-8 stimulated by LPS, flagellin and poly(I:C). Primary amnion cells treated with AMPK activators significantly decreased IL-1β-induced MMP-9 expression. The decrease in AMPK activity in fetal membranes after spontaneous term labour and PPROM indicates an anti-inflammatory role for AMPK in human labour and delivery. The use of AMPK activators as possible therapeutics for threatened preterm labour would be an exciting future avenue of research. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Sulforaphane induced adipolysis via hormone sensitive lipase activation, regulated by AMPK signaling pathway.

    Science.gov (United States)

    Lee, Ju-Hee; Moon, Myung-Hee; Jeong, Jae-Kyo; Park, Yang-Gyu; Lee, You-Jin; Seol, Jae-Won; Park, Sang-Youel

    2012-10-05

    Sulforaphane, an aliphatic isothiocyanate derived from cruciferous vegetables, is known for its antidiabetic properties. The effects of sulforaphane on lipid metabolism in adipocytes are not clearly understood. Here, we investigated whether sulforaphane stimulates lipolysis. Mature adipocytes were incubated with sulforaphane for 24h and analyzed using a lipolysis assay which quantified glycerol released into the medium. We investigated gene expression of hormone-sensitive lipase (HSL), and levels of HSL phosphorylation and AMP-activated protein kinase on sulforaphane-mediated lipolysis in adipocytes. Sulforaphane promoted lipolysis and increased both HSL gene expression and HSL activation. Sulforaphane suppressed AMPK phosphorylation at Thr-172 in a dose-dependent manner, which was associated with a decrease in HSL phosphorylation at Ser-565, enhancing the phosphorylation of HSL Ser-563. Taken together, these results suggest that sulforaphane promotes lipolysis via hormone sensitive lipase activation mediated by decreasing AMPK signal activation in adipocytes. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Nitric oxide increases cyclic GMP levels, AMP-activated protein kinase (AMPK)alpha1-specific activity and glucose transport in human skeletal muscle

    DEFF Research Database (Denmark)

    Deshmukh, A S; Long, Y C; de Castro Barbosa, T

    2010-01-01

    an insulin-independent signalling mechanism. Consistent with this, spermine NONOate increased AMP-activated protein kinase (AMPK)-alpha1-associated activity (1.7-fold, p .... CONCLUSIONS/INTERPRETATION: Pharmacological treatment of skeletal muscle with spermine NONOate increases glucose transport via insulin-independent signalling pathways involving increased intracellular cGMP levels and AMPK-alpha1-associated activity....

  8. Maternal obesity alters fatty acid oxidation, AMPK activity, and associated DNA methylation in mesenchymal stem cells from human infants

    Directory of Open Access Journals (Sweden)

    Kristen E. Boyle

    2017-11-01

    Conclusions: These data suggest that greater infant adiposity is associated with suppressed AMPK activity and reduced lipid oxidation in MSCs from infants born to mothers with obesity and may be an important, early marker of underlying obesity risk.

  9. Intact Regulation of the AMPK Signaling Network in Response to Exercise and Insulin in Skeletal Muscle of Male Patients With Type 2 Diabetes: Illumination of AMPK Activation in Recovery From Exercise.

    Science.gov (United States)

    Kjøbsted, Rasmus; Pedersen, Andreas J T; Hingst, Janne R; Sabaratnam, Rugivan; Birk, Jesper B; Kristensen, Jonas M; Højlund, Kurt; Wojtaszewski, Jørgen F P

    2016-05-01

    Current evidence on exercise-mediated AMPK regulation in skeletal muscle of patients with type 2 diabetes (T2D) is inconclusive. This may relate to inadequate segregation of trimeric complexes in the investigation of AMPK activity. We examined the regulation of AMPK and downstream targets ACC-β, TBC1D1, and TBC1D4 in muscle biopsy specimens obtained from 13 overweight/obese patients with T2D and 14 weight-matched male control subjects before, immediately after, and 3 h after exercise. Exercise increased AMPK α2β2γ3 activity and phosphorylation of ACCβ Ser(221), TBC1D1 Ser(237)/Thr(596), and TBC1D4 Ser(704) Conversely, exercise decreased AMPK α1β2γ1 activity and TBC1D4 Ser(318)/Thr(642) phosphorylation. Interestingly, compared with preexercise, 3 h into exercise recovery, AMPK α2β2γ1 and α1β2γ1 activity were increased concomitant with increased TBC1D4 Ser(318)/Ser(341)/Ser(704) phosphorylation. No differences in these responses were observed between patients with T2D and control subjects. Subjects were also studied by euglycemic-hyperinsulinemic clamps performed at rest and 3 h after exercise. We found no evidence for insulin to regulate AMPK activity. Thus, AMPK signaling is not compromised in muscle of patients with T2D during exercise and insulin stimulation. Our results reveal a hitherto unrecognized activation of specific AMPK complexes in exercise recovery. We hypothesize that the differential regulation of AMPK complexes plays an important role for muscle metabolism and adaptations to exercise. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  10. Oleuropein activated AMPK and induced insulin sensitivity in C2C12 muscle cells.

    Science.gov (United States)

    Hadrich, Fatma; Garcia, Marie; Maalej, Amina; Moldes, Marthe; Isoda, Hiroko; Feve, Bruno; Sayadi, Sami

    2016-04-15

    Oleuropein has been recognized as an important medicinal compound because of its various biological properties, including anti-cancer, antidiabetic and anti-atherosclerotic activities. Here, we evaluate the antioxidant activity as well as the mechanism of the hypoglycemic effects of oleuropein in C2C12 cells and we establish the mechanism underlying these effects. To perform this study, C2C12 cells viability was analyzed via MTT assay and the antioxidant activity was investigated by ROS and TBARS assays. Also, the effect of oleuropein on AMPK and PI3 kinase signaling pathways was evaluated. Treatment with oleuropein was able to protect cells against H2O2 induced stress in cells. On the other hand, the molecular bases of its actions have been scarcely understood. Oleuropein significantly enhanced glucose consumption and the phosphorylation of AMPK (AMP-activated protein kinase/ACC (acetyl-CoA carboxylase)) and MAPKs (mitogen-activated protein kinases), but not PI3 kinase (Phosphatidylinositol 3-kinase)/Akt. However, the co-treatment of oleuropein and insulin improved the insulin sensitivity via insulin-dependent (PI3 kinase/Akt) and insulin independent (AMPK/ACC) pathways. These results could be confirmed from the findings of GLUT4 translocation which was strongly enhanced in the case of oleuropein. Our results provide important insights for the possible mechanism of action of oleuropein as a therapeutic agent in diabetic patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Silencing Nrf2 impairs glioma cell proliferation via AMPK-activated mTOR inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Yue [Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province (China); Wang, Handong, E-mail: njhdwang@hotmail.com [Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province (China); Wang, Qiang [Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province (China); Ding, Hui [Department of Neurosurgery, Jinling Hospital, School of Medicine, Southern Medical University (Guangzhou), 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province (China); Wu, Heming [Department of Neurosurgery, Nanjing Jingdu Hospital, No. 34, Biao 34, Yanggongjing Road, Nanjing 210002, Jiangsu Province (China); Pan, Hao [Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province (China)

    2016-01-15

    Gliomas are the leading cause of death among adults with primary brain malignancies. Treatment for malignant gliomas remains limited, and targeted therapies have been incompletely explored. Nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription regulator for antioxidant and detoxification enzymes, is abundantly expressed in cancer cells. In this study, the role and mechanism of Nrf2 in cancer cell proliferation was investigated in multiple glioma cell lines. We first evaluated the expression patterns of Nrf2 in four glioma cell lines and found all four cell lines expressed Nrf2, but the highest level was observed in U251 cells. We further evaluated the biological functions of Nrf2 in U251 glioma cell proliferation by specific inhibition of Nrf2 using short hairpin RNA (shRNA). We found that Nrf2 depletion inhibited glioma cell proliferation. Nrf2 depletion also decreased colony formation in U251 cells stably expressing Nrf2 shRNA compared to scrambled control shRNA. Moreover, suppression of Nrf2 expression could lead to ATP depletion (with concomitant rise in AMP/ATP ratio) and consequently to AMPK-activated mTOR inhibition. Finally, activation of adenosine monophosphate–activated protein kinase (AMPK) by treated with phenformin, an AMPK agonist, can mimic the inhibitory effect of Nrf2 knockdown in U251 cells. In conclusion, our findings will shed light to the role and mechanism of Nrf2 in regulating glioma proliferation via ATP-depletion-induced AMPK activation and consequent mTOR inhibition, a novel insight into our understanding the role and mechanism of Nrf2 in glioma pathoetiology. To our knowledge, this is also the first report to provide a rationale for the implication of cross-linking between Nrf2 and mTOR signaling.

  12. Effect of curcumin (Curcuma longa extract) on LPS-induced acute lung injury is mediated by the activation of AMPK.

    Science.gov (United States)

    Kim, Joungmin; Jeong, Seong-Wook; Quan, Hui; Jeong, Cheol-Won; Choi, Jeong-Il; Bae, Hong-Beom

    2016-02-01

    Curcumin, a biphenolic compound extracted from turmeric (Curcuma longa), possesses potent anti-inflammatory activity. The present study investigated whether curcumin could increase 5' adenosine monophosphate-activated protein kinase (AMPK) activity in macrophages and modulate the severity of lipopolysaccharide (LPS)-induced acute lung injury. Macrophages were treated with curcumin and then exposed (or not) to LPS. Acute lung injury was induced by intratracheal administration of LPS in BALB/c mice. Curcumin increased phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), a downstream target of AMPK, in a time- and concentration-dependent manner. Curcumin did not increase phosphorylation of liver kinase B1, a primary kinase upstream of AMPK. STO-609, an inhibitor of calcium(2+)/calmodulin-dependent protein kinase kinase, diminished curcumin-induced AMPK phosphorylation, but transforming growth factor-beta-activated kinase 1 inhibitor did not. Curcumin also diminished the LPS-induced increase in phosphorylation of inhibitory κB-alpha and the production of tumor necrosis factor alpha (TNF-α), macrophage inflammatory protein (MIP)-2, and interleukin (IL)-6 by macrophages. Systemic administration of curcumin significantly decreased the production of TNF-α, MIP-2, and IL-6 as well as neutrophil accumulation in bronchoalveolar lavage fluid, and also decreased pulmonary myeloperoxidase levels and the wet/dry weight ratio in mice subjected to LPS treatment. These results suggest that the protective effect of curcumin on LPS-induced acute lung injury is associated with AMPK activation.

  13. AMP-activated protein kinase (AMPK mediates nutrient regulation of thioredoxin-interacting protein (TXNIP in pancreatic beta-cells.

    Directory of Open Access Journals (Sweden)

    Maayan Shaked

    Full Text Available Thioredoxin-interacting protein (TXNIP regulates critical biological processes including inflammation, stress and apoptosis. TXNIP is upregulated by glucose and is a critical mediator of hyperglycemia-induced beta-cell apoptosis in diabetes. In contrast, the saturated long-chain fatty acid palmitate, although toxic to the beta-cell, inhibits TXNIP expression. The mechanisms involved in the opposing effects of glucose and fatty acids on TXNIP expression are unknown. We found that both palmitate and oleate inhibited TXNIP in a rat beta-cell line and islets. Palmitate inhibition of TXNIP was independent of fatty acid beta-oxidation or esterification. AMP-activated protein kinase (AMPK has an important role in cellular energy sensing and control of metabolic homeostasis; therefore we investigated its involvement in nutrient regulation of TXNIP. As expected, glucose inhibited whereas palmitate stimulated AMPK. Pharmacologic activators of AMPK mimicked fatty acids by inhibiting TXNIP. AMPK knockdown increased TXNIP expression in presence of high glucose with and without palmitate, indicating that nutrient (glucose and fatty acids effects on TXNIP are mediated in part via modulation of AMPK activity. TXNIP is transcriptionally regulated by carbohydrate response element-binding protein (ChREBP. Palmitate inhibited glucose-stimulated ChREBP nuclear entry and recruitment to the Txnip promoter, thereby inhibiting Txnip transcription. We conclude that AMPK is an important regulator of Txnip transcription via modulation of ChREBP activity. The divergent effects of glucose and fatty acids on TXNIP expression result in part from their opposing effects on AMPK activity. In light of the important role of TXNIP in beta-cell apoptosis, its inhibition by fatty acids can be regarded as an adaptive/protective response to glucolipotoxicity. The finding that AMPK mediates nutrient regulation of TXNIP may have important implications for the pathophysiology and treatment

  14. Polyphenol-Rich Propolis Extracts Strengthen Intestinal Barrier Function by Activating AMPK and ERK Signaling

    Science.gov (United States)

    Wang, Kai; Jin, Xiaolu; Chen, Yifan; Song, Zehe; Jiang, Xiasen; Hu, Fuliang; Conlon, Michael A.; Topping, David L.

    2016-01-01

    Propolis has abundant polyphenolic constituents and is used widely as a health/functional food. Here, we investigated the effects of polyphenol-rich propolis extracts (PPE) on intestinal barrier function in human intestinal epithelial Caco-2 cells, as well as in rats. In Caco-2 cells, PPE increased transepithelial electrical resistance and decreased lucifer yellow flux. PPE-treated cells showed increased expression of the tight junction (TJ) loci occludin and zona occludens (ZO)-1. Confocal microscopy showed organized expressions in proteins related to TJ assembly, i.e., occludin and ZO-1, in response to PPE. Furthermore, PPE led to the activation of AMPK, ERK1/2, p38, and Akt. Using selective inhibitors, we found that the positive effects of PPE on barrier function were abolished in cells in which AMPK and ERK1/2 signaling were inhibited. Moreover, rats fed a diet supplemented with PPE (0.3% in the diet) exhibited increased colonic epithelium ZO-1 expression. Overall, these data suggest that PPE strengthens intestinal barrier function by activating AMPK and ERK signaling and provide novel insights into the potential application of propolis for human gut health. PMID:27164138

  15. SIRT1 is required for AMPK activation and the beneficial effects of resveratrol on mitochondrial function

    Science.gov (United States)

    Price, Nathan L.; Gomes, Ana P.; Ling, Alvin J.Y.; Duarte, Filipe V.; Martin-Montalvo, Alejandro; North, Brian J.; Agarwal, Beamon; Ye, Lan; Ramadori, Giorgio; Teodoro, Joao S.; Hubbard, Basil P.; Varela, Ana T.; Davis, James G.; Varamini, Behzad; Hafner, Angela; Moaddel, Ruin; Rolo, Anabela P.; Coppari, Roberto; Palmeira, Carlos M.; de Cabo, Rafael; Baur, Joseph A.; Sinclair, David A.

    2012-01-01

    SUMMARY Resveratrol induces mitochondrial biogenesis and protects against metabolic decline but whether SIRT1 mediates these benefits is the subject of debate. To circumvent the developmental defects of germ-line SIRT1 knockouts, we have developed the first inducible system that permits whole-body deletion of SIRT1 in adult mice. Mice treated with a moderate dose of resveratrol showed increased mitochondrial biogenesis and function, AMPK activation and increased NAD+ levels in skeletal muscle, whereas SIRT1 knockouts displayed none of these benefits. A mouse overexpressing SIRT1 mimicked these effects. A high dose of resveratrol activated AMPK in a SIRT1-independent manner, demonstrating that resveratrol dosage is a critical factor. Importantly, at both doses of resveratrol no improvements in mitochondrial function were observed in animals lacking SIRT1. Together these data indicate that SIRT1 plays an essential role in the ability of moderate doses of resveratrol to stimulate AMPK and improve mitochondrial function both in vitro and in vivo. PMID:22560220

  16. FK866-induced NAMPT inhibition activates AMPK and downregulates mTOR signaling in hepatocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Susanne, E-mail: Susanne.Schuster@medizin.uni-leipzig.de [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany); Penke, Melanie; Gorski, Theresa [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany); Gebhardt, Rolf [Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Johannisallee 30, 04103 Leipzig (Germany); Weiss, Thomas S. [Children' s University Hospital, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Kiess, Wieland; Garten, Antje [Center for Pediatric Research Leipzig, University Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Liebigstr. 21, 04103 Leipzig (Germany)

    2015-03-06

    Background: Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway starting from nicotinamide. Cancer cells have an increased demand for NAD due to their high proliferation and DNA repair rate. Consequently, NAMPT is considered as a putative target for anti-cancer therapies. There is evidence that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) become dysregulated during the development of hepatocellular carcinoma (HCC). Here, we investigated the effects of NAMPT inhibition by its specific inhibitor FK866 on the viability of hepatocarcinoma cells and analyzed the effects of FK866 on the nutrient sensor AMPK and mTOR complex1 (mTORC1) signaling. Results: FK866 markedly decreased NAMPT activity and NAD content in hepatocarcinoma cells (Huh7 cells, Hep3B cells) and led to delayed ATP reduction which was associated with increased cell death. These effects could be abrogated by administration of nicotinamide mononucleotide (NMN), the enzyme product of NAMPT. Our results demonstrated a dysregulation of the AMPK/mTOR pathway in hepatocarcinoma cells compared to non-cancerous hepatocytes with a higher expression of mTOR and a lower AMPKα activation in hepatocarcinoma cells. We found that NAMPT inhibition by FK866 significantly activated AMPKα and inhibited the activation of mTOR and its downstream targets p70S6 kinase and 4E-BP1 in hepatocarcinoma cells. Non-cancerous hepatocytes were less sensitive to FK866 and did not show changes in AMPK/mTOR signaling after FK866 treatment. Conclusion: Taken together, these findings reveal an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of hepatocarcinoma cells and suggest NAMPT inhibition as a potential treatment option for HCC. - Highlights: • FK866 increases cell death in p53-deficient hepatocarcinoma cells. • AMPK/mTOR signaling is dysregulated in hepatocarcinoma cells. • FK866-induced NAMPT inhibition activates AMPK

  17. FK866-induced NAMPT inhibition activates AMPK and downregulates mTOR signaling in hepatocarcinoma cells

    International Nuclear Information System (INIS)

    Schuster, Susanne; Penke, Melanie; Gorski, Theresa; Gebhardt, Rolf; Weiss, Thomas S.; Kiess, Wieland; Garten, Antje

    2015-01-01

    Background: Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway starting from nicotinamide. Cancer cells have an increased demand for NAD due to their high proliferation and DNA repair rate. Consequently, NAMPT is considered as a putative target for anti-cancer therapies. There is evidence that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) become dysregulated during the development of hepatocellular carcinoma (HCC). Here, we investigated the effects of NAMPT inhibition by its specific inhibitor FK866 on the viability of hepatocarcinoma cells and analyzed the effects of FK866 on the nutrient sensor AMPK and mTOR complex1 (mTORC1) signaling. Results: FK866 markedly decreased NAMPT activity and NAD content in hepatocarcinoma cells (Huh7 cells, Hep3B cells) and led to delayed ATP reduction which was associated with increased cell death. These effects could be abrogated by administration of nicotinamide mononucleotide (NMN), the enzyme product of NAMPT. Our results demonstrated a dysregulation of the AMPK/mTOR pathway in hepatocarcinoma cells compared to non-cancerous hepatocytes with a higher expression of mTOR and a lower AMPKα activation in hepatocarcinoma cells. We found that NAMPT inhibition by FK866 significantly activated AMPKα and inhibited the activation of mTOR and its downstream targets p70S6 kinase and 4E-BP1 in hepatocarcinoma cells. Non-cancerous hepatocytes were less sensitive to FK866 and did not show changes in AMPK/mTOR signaling after FK866 treatment. Conclusion: Taken together, these findings reveal an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of hepatocarcinoma cells and suggest NAMPT inhibition as a potential treatment option for HCC. - Highlights: • FK866 increases cell death in p53-deficient hepatocarcinoma cells. • AMPK/mTOR signaling is dysregulated in hepatocarcinoma cells. • FK866-induced NAMPT inhibition activates AMPK

  18. Knockdown of MAGEA6 Activates AMP-Activated Protein Kinase (AMPK) Signaling to Inhibit Human Renal Cell Carcinoma Cells.

    Science.gov (United States)

    Ye, Xueting; Xie, Jing; Huang, Hang; Deng, Zhexian

    2018-01-01

    Melanoma antigen A6 (MAGEA6) is a cancer-specific ubiquitin ligase of AMP-activated protein kinase (AMPK). The current study tested MAGEA6 expression and potential function in renal cell carcinoma (RCC). MAGEA6 and AMPK expression in human RCC tissues and RCC cells were tested by Western blotting assay and qRT-PCR assay. shRNA method was applied to knockdown MAGEA6 in human RCC cells. Cell survival and proliferation were tested by MTT assay and BrdU ELISA assay, respectively. Cell apoptosis was tested by the TUNEL assay and single strand DNA ELISA assay. The 786-O xenograft in nude mouse model was established to test RCC cell growth in vivo. MAGEA6 is specifically expressed in RCC tissues as well as in the established (786-O and A498) and primary human RCC cells. MAGEA6 expression is correlated with AMPKα1 downregulation in RCC tissues and cells. It is not detected in normal renal tissues nor in the HK-2 renal epithelial cells. MAGEA6 knockdown by targeted-shRNA induced AMPK stabilization and activation, which led to mTOR complex 1 (mTORC1) in-activation and RCC cell death/apoptosis. AMPK inhibition, by AMPKα1 shRNA or the dominant negative AMPKα1 (T172A), almost reversed MAGEA6 knockdown-induced RCC cell apoptosis. Conversely, expression of the constitutive-active AMPKα1 (T172D) mimicked the actions by MAGEA6 shRNA. In vivo, MAGEA6 shRNA-bearing 786-O tumors grew significantly slower in nude mice than the control tumors. AMPKα1 stabilization and activation as well as mTORC1 in-activation were detected in MAGEA6 shRNA tumor tissues. MAGEA6 knockdown inhibits human RCC cells via activating AMPK signaling. © 2018 The Author(s). Published by S. Karger AG, Basel.

  19. Entada phaseoloides extract suppresses hepatic gluconeogenesis via activation of the AMPK signaling pathway.

    Science.gov (United States)

    Zheng, Tao; Hao, Xincai; Wang, Qibin; Chen, Li; Jin, Si; Bian, Fang

    2016-12-04

    The seed of Entada phaseoloides (L.) Merr. (Entada phaseoloides) has been long used as a folk medicine for the treatment of Diabetes mellitus by Chinese ethnic minorities. Recent reports have demonstrated that total saponins from Entada phaseoloides (TSEP) could reduce fasting blood glucose in type 2 diabetic rats. However, the mechanism has not been fully elucidated. The aim of this study was to explore the underlying mechanisms of TSEP on type 2 Diabetes mellitus (T2DM). Primary mouse hepatocytes and HepG2 cells were used to investigate the effects of TSEP on gluconeogenesis. After treatment with TSEP, glucose production, genes expression levels of Glucose-6-phosphatase (G6pase) and Phosphoenoylpyruvate carboxykinase (Pepck) were detected. The efficacy and underlying mechanism of TSEP on AMP-activated protein kinase (AMPK) signaling pathway were determinated. TSEP significantly inhibited glucose production and the gluconeogenic gene expression. Treatment with TSEP elevated the phosphorylation of AMPK, which in turn promoted the phosphorylation of acetyl coenzyme A (ACC) and Akt/glycogen synthase kinase 3β (GSK3β), respectively. Furthermore, TSEP reduced lipid accumulation and improved insulin sensitivity in hepatocytes. These findings provide evidence that TSEP exerts an antidiabetic effect by suppressing hepatic gluconeogenesis via the AMPK signaling pathway. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Antidiabetic Effect of Salvianolic Acid A on Diabetic Animal Models via AMPK Activation and Mitochondrial Regulation

    Directory of Open Access Journals (Sweden)

    Guifen Qiang

    2015-05-01

    Full Text Available Background/Aims: Diabetes mellitus (DM characterized by hyperglycemia contributes to macrovascular and microvascular complications. Salvianolic acid A (SalA is a polyphenolic compound isolated from the root of Salvia miltiorrhiza Bunge, which is a traditional Chinese medicine widely used to treat cardiovascular diseases. However, little is known about its antidiabetic effect. Our study aimed to investigate the in vivo and in vitro antidiabetic effect of SalA and the underlying mechanisms. Methods: Alloxan-induced type 1 diabetic mice and high-fat diet (HFD and low-dose streptozotocin (STZ-induced type 2 diabetic rats received SalA treatment. Blood glucose, oral glucose tolerance test (OGTT, 24-h food and water intake were monitored. In vitro, glucose consumption and uptake were measured in HepG2 cells and L6 myotubes. Mitochondrial function was detected in hepatic and skeletal muscle mitochondria. AMP-activated protein kinase (AMPK and Akt were analyzed by western blot. Results: In both type 1 and type 2 diabetic animals, SalA lowered fasting blood glucose (FBG and fed blood glucose in dose-dependent manner, as well as reduced 24-h food and water intake. In vitro, SalA caused dose-dependent increase in glucose consumption and enhanced glucose uptake. SalA significantly increased ATP production from 10 min to 12 h in HepG2 cells and L6 myotubes. Interestingly, SalA decreased mitochondrial membrane potential (MMP in HepG2 cells. Furthermore, SalA improved hepatic and skeletal muscle mitochondrial function, increased ATP production, and concurrently decreased MMP. In particularly, SalA activated AMPK phosphorylation through Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ/AMPK signaling pathway, independent of liver kinase 1 (LKB1/AMPK pathway. However, SalA didn't show any effect on insulin secretagogue and activation of PI3K/Akt signaling pathway. Conclusion: SalA exhibits the antidiabetic effects in diabetic animal models through

  1. LPS inhibits caspase 3-dependent apoptosis in RAW264.7 macrophages induced by the AMPK activator AICAR

    Energy Technology Data Exchange (ETDEWEB)

    Russe, Otto Quintus, E-mail: quintus@russe.eu; Möser, Christine V., E-mail: chmoeser@hotmail.com; Kynast, Katharina L., E-mail: katharina.kynast@googlemail.com; King, Tanya S., E-mail: tanya.sarah.king@googlemail.com; Olbrich, Katrin, E-mail: Katrin.olbrich@gmx.net; Grösch, Sabine, E-mail: groesch@em.uni-frankfurt.de; Geisslinger, Gerd, E-mail: geisslinger@em.uni-frankfurt.de; Niederberger, Ellen, E-mail: e.niederberger@em.uni-frankfurt.de

    2014-05-09

    Highlights: • AMPK-activation induces caspase 3-dependent apoptosis in macrophages. • Apoptosis is associated with decreased mTOR and increased p21 levels. • All effects can be significantly inhibited by the TLR4 agonist lipopolysaccharide. - Abstract: AMP-activated kinase is a cellular energy sensor which is activated in stages of increased ATP consumption. Its activation has been associated with a number of beneficial effects such as decreasing inflammatory processes and the disease progress of diabetes and obesity, respectively. Furthermore, AMPK activation has been linked with induction of cell cycle arrest and apoptosis in cancer and vascular cells, indicating that it might have a therapeutic impact for the treatment of cancer and atherosclerosis. However, the impact of AMPK on the proliferation of macrophages, which also play a key role in the formation of atherosclerotic plaques and in inflammatory processes, has not been focused so far. We have assessed the influence of AICAR- and metformin-induced AMPK activation on cell viability of macrophages with and without inflammatory stimulation, respectively. In cells without inflammatory stimulation, we found a strong induction of caspase 3-dependent apoptosis associated with decreased mTOR levels and increased expression of p21. Interestingly, these effects could be inhibited by co-stimulation with bacterial lipopolysaccharide (LPS) but not by other proinflammatory cytokines suggesting that AICAR induces apoptosis via AMPK in a TLR4-pathway dependent manner. In conclusion, our results revealed that AMPK activation is not only associated with positive effects but might also contribute to risk factors by disturbing important features of macrophages. The fact that LPS is able to restore AMPK-associated apoptosis might indicate an important role of TLR4 agonists in preventing unfavorable cell death of immune cells.

  2. Modulation of de novo purine biosynthesis leads to activation of AMPK and results in improved glucose handling and insulin sensitivity.

    Science.gov (United States)

    Sadasivan, Satish Kumar; Vasamsetti, Balamuralikrishna; Singh, Jaideep; Siddaraju, Nethra; Khan, Khaiser Mehdi; Oommen, Anup Mammen; Jagannath, Madanalli R; Rao, Raghavendra Pralhada

    2014-01-01

    AMP activated protein kinase (AMPK) regulates key metabolic reactions and plays a major role in glucose homeostasis. Activating the AMPK is considered as one of the potential therapeutic strategies in treating type-2 diabetes. However, targeting AMPK by small molecule mediated approach can be challenging owing to diverse isoforms of the enzyme and their varied combination in different tissues. In the current study we employ a novel strategy of achieving AMPK activation through increasing the levels of cellular AMP (an allosteric activator of AMPK) levels by activating the enzyme involved in AMP biosynthesis namely Adenylosuccinate lyase (ADSL). Rat primary hepatocytes were cultured under metabolic overload conditions (500 μM palmitate) to induce insulin resistance. ADSL was overexpressed in these hepatocytes and its effect on hepatic glucose output, and triglyceride accumulation was checked. In addition to this, ADSL was overexpressed in high fat diet induced obese mice by hydrodynamic tail vein injection and its effect on fasting glucose, glucose tolerance and pyruvate tolerance were checked. Rat primary hepatocytes when cultured under metabolic overload conditions developed insulin resistance as measured in terms of failure of insulin to suppress the glucose output. Overexpressing the ADSL in these hepatocytes resulted in increased AMPK phosporylation and improved the insulin sensitivity and also resulted in reduced triglyceride accumulation and inflammatory cytokine levels. In addition to this, when ADSL was overexpressed in high fat diet induced obese mice, it resulted in reduced the fasting hyperglycemia (20% reduction), and increased glucose and pyruvate tolerance. This study indicates that activating ADSL can be a potential mechanism to achieve the activation of AMPK in the cells. This leads to a novel idea of exploring the purine nucleotide metabolic pathway as a promising therapeutic target for diabetes and metabolic syndrome.

  3. Noise-Induced Loss of Hair Cells and Cochlear Synaptopathy Are Mediated by the Activation of AMPK

    Science.gov (United States)

    Hill, Kayla; Yuan, Hu; Wang, Xianren

    2016-01-01

    Noise-induced hearing loss (NIHL) is a major unresolved public health problem. Here, we investigate pathomechanisms of sensory hair cell death and suggest a novel target for protective intervention. Cellular survival depends upon maintenance of energy homeostasis, largely by AMP-activated protein kinase (AMPK). In response to a noise exposure in CBA/J mice, the levels of phosphorylated AMPKα increased in hair cells in a noise intensity-dependent manner. Inhibition of AMPK via siRNA or the pharmacological inhibitor compound C attenuated noise-induced loss of outer hair cells (OHCs) and synaptic ribbons, and preserved auditory function. Additionally, noise exposure increased the activity of the upstream AMPK kinase liver kinase B1 (LKB1) in cochlear tissues. The inhibition of LKB1 by siRNA attenuated the noise-increased phosphorylation of AMPKα in OHCs, reduced the loss of inner hair cell synaptic ribbons and OHCs, and protected against NIHL. These results indicate that noise exposure induces hair cell death and synaptopathy by activating AMPK via LKB1-mediated pathways. Targeting these pathways may provide a novel route to prevent NIHL. SIGNIFICANCE STATEMENT Our results demonstrate for the first time that the activation of AMP-activated protein kinase (AMPK) α in sensory hair cells is noise intensity dependent and contributes to noise-induced hearing loss by mediating the loss of inner hair cell synaptic ribbons and outer hair cells. Noise induces the phosphorylation of AMPKα1 by liver kinase B1 (LKB1), triggered by changes in intracellular ATP levels. The inhibition of AMPK activation by silencing AMPK or LKB1, or with the pharmacological inhibitor compound C, reduced outer hair cell and synaptic ribbon loss as well as noise-induced hearing loss. This study provides new insights into mechanisms of noise-induced hearing loss and suggests novel interventions for the prevention of the loss of sensory hair cells and cochlear synaptopathy. PMID:27413159

  4. AMPK alpha1 activation is required for stimulation of glucose uptake by twitch contraction, but not by H2O2, in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Schjerling, Peter; Viollet, Benoit

    2008-01-01

    into muscle by certain stimuli. In contrast, no clear function has yet been determined for alpha(1) AMPK in skeletal muscle, possibly due to alpha-AMPK isoform signaling redundancy. By applying low-intensity twitch-contraction and H(2)O(2) stimulation to activate alpha(1) AMPK, but not alpha(2) AMPK......, in wildtype and alpha-AMPK transgenic mouse muscles, this study aimed to define conditions where alpha(1) AMPK is required to increase muscle glucose uptake. METHODOLOGY/PRINCIPAL FINDINGS: Following stimulation with H(2)O(2) (3 mM, 20 min) or twitch-contraction (0.1 ms pulse, 2 Hz, 2 min), signaling and 2......-deoxyglucose uptake were measured in incubated soleus muscles from wildtype and muscle-specific kinase-dead AMPK (KD), alpha(1) AMPK knockout or alpha(2) AMPK knockout mice. H(2)O(2) increased the activity of both alpha(1) and alpha(2) AMPK in addition to Akt phosphorylation, and H(2)O(2)-stimulated glucose...

  5. GSK3β-dependent inhibition of AMPK potentiates activation of neutrophils and macrophages and enhances severity of acute lung injury

    Science.gov (United States)

    Park, Dae Won; Jiang, Shaoning; Liu, Yanping; Siegal, Gene P.; Inoki, Ken; Abraham, Edward

    2014-01-01

    Although AMP-activated protein kinase (AMPK) is involved in regulating carbohydrate and lipid metabolism, activated AMPK also plays an anti-inflammatory role in many cell populations. However, despite the ability of AMPK activation to diminish the severity of inflammatory responses, previous studies have found that AMPK activity is diminished in LPS-treated neutrophils and also in lungs of mice with LPS-induced acute lung injury (ALI). Since GSK3β participates in regulating AMPK activity, we examined potential roles for GSK3β in modulating LPS-induced activation of neutrophils and macrophages and in influencing severity of ALI. We found that GSK3β-dependent phosphorylation of T479-AMPK was associated with pT172 dephosphorylation and inactivation of AMPK following TLR4 engagement. GSK3β inhibitors BIO (6-bromoindirubin-3′-oxime), SB216763, or siRNA knockdown of GSK3β, but not the PI3K/AKT inhibitor LY294002, prevented Thr172-AMPK dephosphorylation. Exposure to LPS resulted in rapid binding between IKKβ and AMPKα, and phosphorylation of S485-AMPK by IKKβ. These results suggest that IKKβ-dependent phosphorylation of S485-AMPK was an essential step in subsequent phosphorylation and inactivation AMPK by GSK3β. Inhibition of GSK3β activity delayed IκBα degradation and diminished expression of the proinflammatory TNF-α in LPS-stimulated neutrophils and macrophages. In vivo, inhibition of GSK3β decreased the severity of LPS-induced lung injury as assessed by development of pulmonary edema, production of TNF-α and MIP-2, and release of the alarmins HMGB1 and histone 3 in the lungs. These results show that inhibition of AMPK by GSK3β plays an important contributory role in enhancing LPS-induced inflammatory responses, including worsening the severity of ALI. PMID:25239914

  6. Ginkgolic acid inhibits the invasiveness of colon cancer cells through AMPK activation.

    Science.gov (United States)

    Qiao, Lina; Zheng, Jianbao; Jin, Xianzhen; Wei, Guangbing; Wang, Guanghui; Sun, Xuejun; Li, Xuqi

    2017-11-01

    Tumor cell invasion and metastasis are important processes in colorectal cancer that exert negative effects on patient outcomes; consequently, a prominent topic in the field of colorectal cancer study is the identification of safe and affordable anticancer drugs against cell invasion and metastasis, with limited side effects. Ginkgolic acid is a phenolic acid extracted from ginkgo fruit, ginkgo exotesta and ginkgo leaves. Previous studies have indicated that ginkgolic acid inhibits tumor growth and invasion in a number of types of cancer; however, limited studies have considered the effects of ginkgolic acid on colon cancer. In the present study, SW480 colon cancer cells were treated with a range of concentrations of ginkgolic acid; tetrazolium dye-based MTT, wound-scratch and transwell migration assays were performed to investigate the effects on the proliferation, migration and invasion of colon cancer cells, and potential mechanisms for the effects were explored. The results indicated that ginkgolic acid reduced the proliferation and significantly inhibited the migration and invasion of SW480 cells in a concentration-dependent manner. Additional experiments indicated that ginkgolic acid significantly decreased the expression of invasion-associated proteins, including matrix metalloproteinase (MMP)-2, MMP-9, urinary-type plasminogen activator and C-X-C chemokine receptor type 4, and activated adenosine monophosphate activated protein kinase (AMPK) in SW480 cells. Small interfering RNA silencing of AMPK expression reversed the effect of ginkgolic acid on the expression of invasion-associated proteins. This result suggested that ginkgolic acid inhibited the proliferation, migration and invasion of SW480 colon cancer cells by inducing AMPK activation and inhibiting the expression of invasion-associated proteins.

  7. PT-1 selectively activates AMPK-γ1 complexes in mouse skeletal muscle, but activates all three γ subunit complexes in cultured human cells by inhibiting the respiratory chain

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Ross, Fiona A; Kleinert, Maximilian

    2015-01-01

    strategy to combat diseases such as cancer and type 2 diabetes. We report that the AMPK activator PT-1 selectively increased the activity of γ1- but not γ3-containing complexes in incubated mouse muscle. PT-1 increased the AMPK-dependent phosphorylation of the autophagy-regulating kinase ULK1 on Ser555...... AMPK by direct binding between the kinase and auto-inhibitory domains of the α subunit. We show instead that PT-1 activates AMPK indirectly by inhibiting the respiratory chain and increasing cellular AMP:ATP and/or ADP:ATP ratios. Consistent with this mechanism, PT-1 failed to activate AMPK in HEK-293...

  8. AMPK activation through mitochondrial regulation results in increased substrate oxidation and improved metabolic parameters in models of diabetes.

    Directory of Open Access Journals (Sweden)

    Yonchu Jenkins

    Full Text Available Modulation of mitochondrial function through inhibiting respiratory complex I activates a key sensor of cellular energy status, the 5'-AMP-activated protein kinase (AMPK. Activation of AMPK results in the mobilization of nutrient uptake and catabolism for mitochondrial ATP generation to restore energy homeostasis. How these nutrient pathways are affected in the presence of a potent modulator of mitochondrial function and the role of AMPK activation in these effects remain unclear. We have identified a molecule, named R419, that activates AMPK in vitro via complex I inhibition at much lower concentrations than metformin (IC50 100 nM vs 27 mM, respectively. R419 potently increased myocyte glucose uptake that was dependent on AMPK activation, while its ability to suppress hepatic glucose production in vitro was not. In addition, R419 treatment of mouse primary hepatocytes increased fatty acid oxidation and inhibited lipogenesis in an AMPK-dependent fashion. We have performed an extensive metabolic characterization of its effects in the db/db mouse diabetes model. In vivo metabolite profiling of R419-treated db/db mice showed a clear upregulation of fatty acid oxidation and catabolism of branched chain amino acids. Additionally, analyses performed using both (13C-palmitate and (13C-glucose tracers revealed that R419 induces complete oxidation of both glucose and palmitate to CO2 in skeletal muscle, liver, and adipose tissue, confirming that the compound increases mitochondrial function in vivo. Taken together, our results show that R419 is a potent inhibitor of complex I and modulates mitochondrial function in vitro and in diabetic animals in vivo. R419 may serve as a valuable molecular tool for investigating the impact of modulating mitochondrial function on nutrient metabolism in multiple tissues and on glucose and lipid homeostasis in diabetic animal models.

  9. Nootkatone, a characteristic constituent of grapefruit, stimulates energy metabolism and prevents diet-induced obesity by activating AMPK.

    Science.gov (United States)

    Murase, Takatoshi; Misawa, Koichi; Haramizu, Satoshi; Minegishi, Yoshihiko; Hase, Tadashi

    2010-08-01

    AMP-activated protein kinase (AMPK) is a serine/threonine kinase that is implicated in the control of energy metabolism and is considered to be a molecular target for the suppression of obesity and the treatment of metabolic syndrome. Here, we identified and characterized nootkatone, a constituent of grapefruit, as a naturally occurring AMPK activator. Nootkatone induced an increase in AMPKalpha1 and -alpha2 activity along with an increase in the AMP/ATP ratio and an increase the phosphorylation of AMPKalpha and the downstream target acetyl-CoA carboxylase (ACC), in C(2)C(12) cells. Nootkatone-induced activation of AMPK was possibly mediated both by LKB1 and Ca(2+)/calmodulin-dependent protein kinase kinase. Nootkatone also upregulated PPARgamma coactivator-1alpha in C(2)C(12) cells and C57BL/6J mouse muscle. In addition, administration of nootkatone (200 mg/kg body wt) significantly enhanced AMPK activity, accompanied by LKB1, AMPK, and ACC phosphorylation in the liver and muscle of mice. Whole body energy expenditure evaluated by indirect calorimetry was also increased by nootkatone administration. Long-term intake of diets containing 0.1% to 0.3% (wt/wt) nootkatone significantly reduced high-fat and high-sucrose diet-induced body weight gain, abdominal fat accumulation, and the development of hyperglycemia, hyperinsulinemia, and hyperleptinemia in C57BL/6J mice. Furthermore, endurance capacity, evaluated as swimming time to exhaustion in BALB/c mice, was 21% longer in mice fed 0.2% nootkatone than in control mice. These findings indicate that long-term intake of nootkatone is beneficial toward preventing obesity and improving physical performance and that these effects are due, at least in part, to enhanced energy metabolism through AMPK activation in skeletal muscle and liver.

  10. Activation of AMPK by Buddleja officinalis Maxim. Flower Extract Contributes to Protecting Hepatocytes from Oxidative Stress.

    Science.gov (United States)

    Jung, Ji Yun; Lee, Chul Won; Park, Sang Mi; Jegal, Kyung Hwan; Kim, Jae Kwang; Park, Chung A; Cho, Il Je; Jung, Dae Hwa; An, Won G; Ku, Sae Kwang; Zhao, Rongjie; Kim, Sang Chan

    2017-01-01

    The Buddleja officinalis Maxim. flower is used in traditional Chinese and Korean medicine to treat inflammation, vascular diseases, headache, and stroke, as well as enhance liver function. This research investigated the effects of B. officinalis Maxim. flower extract (BFE) on hepatotoxicity. The cytoprotective effects and mechanism of BFE against severe mitochondrial dysfunction and H 2 O 2 production in hepatotoxicity induced by coadministration of arachidonic acid (AA) and iron were observed in the HepG2 cell line. In addition, we performed blood biochemical, histopathological, and histomorphometric analyses of mice with carbon tetrachloride- (CCl 4 -) induced acute liver damage. BFE inhibited the AA + iron-mediated hepatotoxicity of HepG2 cells. Moreover, it inhibited mitochondrial dysfunction, H 2 O 2 production, and glutathione depletion mediated by AA + iron in the same cells. Meanwhile, the cytoprotective effects of BFE against oxidative stress were associated with the activation of AMP-activated protein kinase (AMPK). In particular, based on the histopathological observations, BFE (30 and 100 mg/kg) showed clear hepatoprotective effects against CCl 4 -induced acute hepatic damage. Furthermore, it inhibited 4-hydroxynonenal and nitrotyrosine immunoreactivity in hepatocytes. These results provide evidence that BFE has beneficial hepatoprotective effects against hepatic damage via the activation of AMPK pathway. Accordingly, BFE may have therapeutic potential for diverse liver disorders.

  11. Activation of AMPK by Buddleja officinalis Maxim. Flower Extract Contributes to Protecting Hepatocytes from Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Ji Yun Jung

    2017-01-01

    Full Text Available The Buddleja officinalis Maxim. flower is used in traditional Chinese and Korean medicine to treat inflammation, vascular diseases, headache, and stroke, as well as enhance liver function. This research investigated the effects of B. officinalis Maxim. flower extract (BFE on hepatotoxicity. The cytoprotective effects and mechanism of BFE against severe mitochondrial dysfunction and H2O2 production in hepatotoxicity induced by coadministration of arachidonic acid (AA and iron were observed in the HepG2 cell line. In addition, we performed blood biochemical, histopathological, and histomorphometric analyses of mice with carbon tetrachloride- (CCl4- induced acute liver damage. BFE inhibited the AA + iron-mediated hepatotoxicity of HepG2 cells. Moreover, it inhibited mitochondrial dysfunction, H2O2 production, and glutathione depletion mediated by AA + iron in the same cells. Meanwhile, the cytoprotective effects of BFE against oxidative stress were associated with the activation of AMP-activated protein kinase (AMPK. In particular, based on the histopathological observations, BFE (30 and 100 mg/kg showed clear hepatoprotective effects against CCl4-induced acute hepatic damage. Furthermore, it inhibited 4-hydroxynonenal and nitrotyrosine immunoreactivity in hepatocytes. These results provide evidence that BFE has beneficial hepatoprotective effects against hepatic damage via the activation of AMPK pathway. Accordingly, BFE may have therapeutic potential for diverse liver disorders.

  12. Compound 13, an α1-selective small molecule activator of AMPK, inhibits Helicobacter pylori-induced oxidative stresses and gastric epithelial cell apoptosis

    International Nuclear Information System (INIS)

    Zhao, Hangyong; Zhu, Huanghuang; Lin, Zhou; Lin, Gang; Lv, Guoqiang

    2015-01-01

    Half of the world's population experiences Helicobacter pylori (H. pylori) infection, which is a main cause of gastritis, duodenal and gastric ulcer, and gastric cancers. In the current study, we investigated the potential role of compound 13 (C13), a novel α1-selective small molecule activator of AMP-activated protein kinase (AMPK), against H. pylori-induced cytotoxicity in cultured gastric epithelial cells (GECs). We found that C13 induced significant AMPK activation, evidenced by phosphorylation of AMPKα1 and ACC (acetyl-CoA carboxylase), in both primary and transformed GECs. Treatment of C13 inhibited H. pylori-induced GEC apoptosis. AMPK activation was required for C13-mediated GEC protection. Inhibition of AMPK kinase activity by the AMPK inhibitor Compound C, or silencing AMPKα1 expression by targeted-shRNAs, alleviated C13-induced GEC protective activities against H. pylori. Significantly, C13 inhibited H. pylori-induced reactive oxygen species (ROS) production in GECs. C13 induced AMPK-dependent expression of anti-oxidant gene heme oxygenase (HO-1) in GECs. Zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP), two HO-1 inhibitors, not only suppressed C13-mediated ROS scavenging activity, but also alleviated its activity in GECs against H. pylori. Together, these results indicate that C13 inhibits H. pylori-induced ROS production and GEC apoptosis through activating AMPK–HO–1 signaling. - Highlights: • We synthesized compound 13 (C13), a α1-selective small molecule AMPK activator. • C13-induced AMPK activation requires α1 subunit in gastric epithelial cells (GECs). • C13 enhances Helicobacter pylori-induced pro-survival AMPK activation to inhibit GEC apoptosis. • C13 inhibits H. pylori-induced reactive oxygen species (ROS) production in GECs. • AMPK-heme oxygenase (HO-1) activation is required for C13-mediated anti-oxidant activity

  13. Compound 13, an α1-selective small molecule activator of AMPK, inhibits Helicobacter pylori-induced oxidative stresses and gastric epithelial cell apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hangyong; Zhu, Huanghuang; Lin, Zhou; Lin, Gang; Lv, Guoqiang, E-mail: lvguoqiangwuxivip@163.com

    2015-08-07

    Half of the world's population experiences Helicobacter pylori (H. pylori) infection, which is a main cause of gastritis, duodenal and gastric ulcer, and gastric cancers. In the current study, we investigated the potential role of compound 13 (C13), a novel α1-selective small molecule activator of AMP-activated protein kinase (AMPK), against H. pylori-induced cytotoxicity in cultured gastric epithelial cells (GECs). We found that C13 induced significant AMPK activation, evidenced by phosphorylation of AMPKα1 and ACC (acetyl-CoA carboxylase), in both primary and transformed GECs. Treatment of C13 inhibited H. pylori-induced GEC apoptosis. AMPK activation was required for C13-mediated GEC protection. Inhibition of AMPK kinase activity by the AMPK inhibitor Compound C, or silencing AMPKα1 expression by targeted-shRNAs, alleviated C13-induced GEC protective activities against H. pylori. Significantly, C13 inhibited H. pylori-induced reactive oxygen species (ROS) production in GECs. C13 induced AMPK-dependent expression of anti-oxidant gene heme oxygenase (HO-1) in GECs. Zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP), two HO-1 inhibitors, not only suppressed C13-mediated ROS scavenging activity, but also alleviated its activity in GECs against H. pylori. Together, these results indicate that C13 inhibits H. pylori-induced ROS production and GEC apoptosis through activating AMPK–HO–1 signaling. - Highlights: • We synthesized compound 13 (C13), a α1-selective small molecule AMPK activator. • C13-induced AMPK activation requires α1 subunit in gastric epithelial cells (GECs). • C13 enhances Helicobacter pylori-induced pro-survival AMPK activation to inhibit GEC apoptosis. • C13 inhibits H. pylori-induced reactive oxygen species (ROS) production in GECs. • AMPK-heme oxygenase (HO-1) activation is required for C13-mediated anti-oxidant activity.

  14. Synthesis and In Vitro AMPK Activation of Cycloalkyl/Alkarylbiguanides with Robust In Vivo Antihyperglycemic Action

    Directory of Open Access Journals (Sweden)

    Erika Gutierrez-Lara

    2017-01-01

    Full Text Available This work describes the design, synthesis in one step, and the in vitro, in vivo, and in silico antidiabetic evaluation of a series of ten alicyclic and aromatic (alkyl +aryl: alkarylbiguanides, analogues of metformin and phenformin. The design was conceived using isosteric replacement, chain-ring transformation, and lower and higher homologation strategies. All compounds were obtained as crystals and their structure was confirmed on the basis of their spectral data (NMR and mass spectra, and their purity was ascertained by microanalysis. Compounds were in vitro evaluated as activators of AMP-Activated Protein Kinase (AMPK. The results indicated that compounds 4, 5, and 6 showed similar or even better effect compared to metformin. Docking analysis was performed with regulatory subunit γ of AMPK, showing several interactions with nucleotide binding pocket. The in vivo evaluation of compounds 4–6 at a single dose of 50 mg/kg was performed in a murine experimental model of diabetes. The results showed an important and robust decrease of plasmatic glucose levels (−40%. Compound 6 was selected for an oral glucose tolerance test, showing an antihyperglycemic effect similar to metformin. The in vivo results indicated that compounds 4–6 may be effective in treating experimental T2DM.

  15. AMPK activation restores ischemic post‑conditioning cardioprotection in STZ‑induced type 1 diabetic rats: Role of autophagy.

    Science.gov (United States)

    Zhou, Bin; Leng, Yan; Lei, Shao-Qing; Xia, Zhong-Yuan

    2017-09-01

    Although the mechanism remains unclear, ischemic post‑conditioning (IPO) is a promising approach to combat myocardial ischemia reperfusion (IR) injury; however, it has been proven ineffective in diabetes. The present study aimed to identify whether hyperglycemia‑induced AMP‑activated protein kinase (AMPK) inhibition contributes to the ineffectiveness of IPO via autophagy attenuation in diabetic hearts. Diabetic and non‑diabetic rats were subjected to myocardial IR and/or IPO with/without treatment with the AMPK activator A‑769662 and/or autophagy inhibitor 3‑methyladenine (3‑MA). Rat cardiomyocyte H9c2 cells were pretreated with A‑769662 and/or 3‑MA, and subjected to hypoxia reoxygenation (HR) or hypoxia post‑conditioning (HPO). The degree of injury to the myocardium/cells, oxidative stress, AMPK/mammalian target of rapamycin (mTOR) signaling and autophagy status were analyzed. In diabetic rats the myocardial infarct size, and creatine kinase‑MB and malondialdehyde release, were increased compared with non‑diabetic rats, concomitant with increased cardiac dysfunction and decreased cardiac superoxide dismutase activity, AMPK phosphorylation and autophagy following IR. IPO attenuated myocardial infarct size, increased AMPK phosphorylation and enhanced autophagy in non‑diabetic animals. A‑769662 (6.0 mg/kg) restored IPO cardioprotection in diabetic rats. In vitro, HPO combined with A‑769662 decreased HR injury in H9c2 cells exposed to high glucose, as evidenced by decreased lactic dehydrogenase expression and oxidative stress, accompanied by increased cell viability and autophagy. The A‑769662‑mediated restoration of IPO/HPO cardioprotection was completely reversed by treatment with the autophagy inhibitor 3‑MA. In conclusion, AMPK inhibition, by decreasing autophagy, may be a mechanism through which diabetic hearts are rendered unresponsive to IPO cardioprotection.

  16. Cardiovascular Protective Effect of Metformin and Telmisartan: Reduction of PARP1 Activity via the AMPK-PARP1 Cascade.

    Directory of Open Access Journals (Sweden)

    Fenqing Shang

    Full Text Available Hyperglycemia and hypertension impair endothelial function in part through oxidative stress-activated poly (ADP-ribose polymerase 1 (PARP1. Biguanides and angiotensin II receptor blockers (ARBs such as metformin and telmisartan have a vascular protective effect. We used cultured vascular endothelial cells (ECs, diabetic and hypertensive rodent models, and AMPKα2-knockout mice to investigate whether metformin and telmisartan have a beneficial effect on the endothelium via AMP-activated protein kinase (AMPK phosphorylation of PARP1 and thus inhibition of PARP1 activity. The results showed that metformin and telmisartan, but not glipizide and metoprolol, activated AMPK, which phosphorylated PARP1 Ser-177 in cultured ECs and the vascular wall of rodent models. Experiments using phosphorylated/de-phosphorylated PARP1 mutants show that AMPK phosphorylation of PARP1 leads to decreased PARP1 activity and attenuated protein poly(ADP-ribosylation (PARylation, but increased endothelial nitric oxide synthase (eNOS activity and silent mating type information regulation 2 homolog 1 (SIRT1 expression. Taken together, the data presented here suggest biguanides and ARBs have a beneficial effect on the vasculature by the cascade of AMPK phosphorylation of PARP1 to inhibit PARP1 activity and protein PARylation in ECs, thereby mitigating endothelial dysfunction.

  17. Enhanced Expression of WD Repeat-Containing Protein 35 via CaMKK/AMPK Activation in Bupivacaine-Treated Neuro2a Cells

    Science.gov (United States)

    Huang, Lei; Kondo, Fumio; Gosho, Masahiko; Feng, Guo-Gang; Harato, Misako; Xia, Zhong-yuan; Ishikawa, Naohisa; Fujiwara, Yoshihiro; Okada, Shoshiro

    2014-01-01

    We previously reported that bupivacaine induces reactive oxygen species (ROS) generation, p38 mitogen-activated protein kinase (MAPK) activation and nuclear factor-kappa B activation, resulting in an increase in expression of WD repeat-containing protein 35 (WDR35) in mouse neuroblastoma Neuro2a cells. However, the identity of signaling upstream of p38 MAPK pathways to WDR35 expression remains unclear. It has been shown that AMP-activated protein kinase (AMPK) can activate p38 MAPK through diverse mechanisms. In addition, several kinases acting upstream of AMPK have been identified including Ca2+/calmodulin-dependent protein kinase kinase (CaMKK). Recent studies reported that AMPK may be involved in bupivacaine-induced cytotoxicity in Schwann cells and in human neuroblastoma SH-SY5Y cells. The present study was undertaken to test whether CaMKK and AMPK are involved in bupivacaine-induced WDR35 expression in Neuro2a cells. Our results showed that bupivacaine induced activation of AMPK and p38 MAPK in Neuro2a cells. The AMPK inhibitors, compound C and iodotubercidin, attenuated the bupivacaine-induced activation of AMPK and p38 MAPK, resulting in an inhibition of the bupivacaine-induced increase in WDR35 expression. Treatment with the CaMKK inhibitor STO-609 also attenuated the bupivacaine-induced activation of AMPK and p38 MAPK, resulting in an inhibition of the bupivacaine-induced increase in WDR35 expression. These results suggest that bupivacaine activates AMPK and p38 MAPK via CaMKK in Neuro2a cells, and that the CaMKK/AMPK/p38 MAPK pathway is involved in regulating WDR35 expression. PMID:24859235

  18. Fenofibrate down-regulates the expressions of androgen receptor (AR) and AR target genes and induces oxidative stress in the prostate cancer cell line LNCaP

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hu; Zhu, Chen; Qin, Chao [State Key Laboratory of Reproductive Medicine, Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Tao, Tao [Department of Neurosurgery, First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Li, Jie; Cheng, Gong; Li, Pu; Cao, Qiang; Meng, Xiaoxin; Ju, Xiaobing; Shao, Pengfei; Hua, Lixin [State Key Laboratory of Reproductive Medicine, Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Gu, Min, E-mail: medzhao1980@163.com [State Key Laboratory of Reproductive Medicine, Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Yin, Changjun, E-mail: drcjyin@gmail.com [State Key Laboratory of Reproductive Medicine, Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing (China)

    2013-03-08

    Highlights: ► Fenofibrate induces cell cycle arrest in G1 phase and apoptosis in LNCaP cells. ► Fenofibrate reduces the expressions of androgen receptor in LNCaP cells. ► Fenofibrate induces oxidative stress in the prostate cancer cell line LNCaP. -- Abstract: Fenofibrate, a peroxisome proliferator-androgen receptor-alpha agonist, is widely used in treating different forms of hyperlipidemia and hypercholesterolemia. Recent reports have indicated that fenofibrate exerts anti-proliferative and pro-apoptotic properties. This study aims to investigate the effects of fenofibrate on the prostate cancer (PCa) cell line LNCaP. The effects of fenofibrate on LNCaP cells were evaluated by flow cytometry, reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assays, Western blot analysis, and dual-luciferase reporter assay. Fenofibrate induces cell cycle arrest in G1 phase and apoptosis in LNCaP cells, reduces the expressions of androgen receptor (AR) and AR target genes (prostate-specific antigen and TMPRSS2), and inhibits Akt phosphorylation. Fenofibrate can induce the accumulation of intracellular reactive oxygen species and malondialdehyde, and decrease the activities of total anti-oxidant and superoxide dismutase in LNCaP cells. Fenofibrate exerts an anti-proliferative property by inhibiting the expression of AR and induces apoptosis by causing oxidative stress. Therefore, our data suggest fenofibrate may have beneficial effects in fenofibrate users by preventing prostate cancer growth through inhibition of androgen activation and expression.

  19. Hearts lacking plasma membrane KATPchannels display changes in basal aerobic metabolic substrate preference and AMPK activity.

    Science.gov (United States)

    Youssef, Nermeen; Campbell, Scott; Barr, Amy; Gandhi, Manoj; Hunter, Beth; Dolinsky, Vernon; Dyck, Jason R B; Clanachan, Alexander S; Light, Peter E

    2017-09-01

    Cardiac ATP-sensitive K + (K ATP ) channels couple changes in cellular metabolism to membrane excitability and are activated during metabolic stress, although under basal aerobic conditions, K ATP channels are thought to be predominately closed. Despite intense research into the roles of K ATP channels during metabolic stress, their contribution to aerobic basal cardiac metabolism has not been previously investigated. Hearts from Kir6.2 +/+ and Kir6.2 -/- mice were perfused in working mode, and rates of glycolysis, fatty acid oxidation, and glucose oxidation were measured. Changes in activation/expression of proteins regulating metabolism were probed by Western blot analysis. Despite cardiac mechanical function and metabolic efficiency being similar in both groups, hearts from Kir6.2 -/- mice displayed an approximately twofold increase in fatty acid oxidation and a 0.45-fold reduction in glycolytic rates but similar glucose oxidation rates compared with hearts from Kir6.2 +/+ mice. Kir6.2 -/- hearts also possessed elevated levels of activated AMP-activated protein kinase (AMPK), higher glycogen content, and reduced mitochondrial density. Moreover, activation of AMPK by isoproterenol or diazoxide was significantly blunted in Kir6.2 -/- hearts. These data indicate that K ATP channel ablation alters aerobic basal cardiac metabolism. The observed increase in fatty acid oxidation and decreased glycolysis before any metabolic insult may contribute to the poor recovery observed in Kir6.2 -/- hearts in response to exercise or ischemia-reperfusion injury. Therefore, K ATP channels may play an important role in the regulation of cardiac metabolism through AMPK signaling. NEW & NOTEWORTHY In this study, we show that genetic ablation of plasma membrane ATP-sensitive K + channels results in pronounced changes in cardiac metabolic substrate preference and AMP-activated protein kinase activity. These results suggest that ATP-sensitive K + channels may play a novel role in

  20. PF-4708671 activates AMPK independently of p70S6K1 inhibition.

    Directory of Open Access Journals (Sweden)

    Gilad W Vainer

    Full Text Available The P70 ribosomal protein S6 kinase 1 (P70S6K1 is activated by the mammalian target of rapamycin (mTORC1 and regulates proliferation, growth, and metabolism. PF-4708671 is a novel, cell-permeable, has been proposed to be a highly specific inhibitor of p70S6K1. It is used in micromolar concentration range to dissect signaling pathways downstream of mTORC1 and to study the function of p70S6K1. Here we show that PF-4708671 induces AMP-activated protein kinase (AMPK phosphorylation and activation in immortalized mouse embryonic fibroblasts (MEF independently of p70S6K1, due to specific inhibition of mitochondrial respiratory chain Complex I.

  1. AKT and AMPK activation after high-fat and high-glucose in vitro treatment of prostate epithelial cells.

    Science.gov (United States)

    Ribeiro, D L; Góes, R M; Pinto-Fochi, M E; Taboga, S R; Abrahamsson, P-A; Dizeyi, N

    2014-06-01

    Considering the increasing consumption of saturated fat and glucose in diets worldwide and its possible association to carcinogenesis, this investigation analysed the proliferation profile of nonmalignant human prostate epithelial cells after exposure to elevated levels of fat and glucose. PNT1A cells were cultured with palmitate (100 or 200 μM) and/or glucose (450 mg/dl) for 24 or 48 h. Treated cells were evaluated for viability test and cell proliferation (MTS assay). AKT and AMPK phosphorylation status were analysed by Western blotting. After 24 h of high-fat alone or associated with high-glucose treatment, there was an increase in AMPK and AKT activation associated to unchanged MTS-cell proliferation. Following 48 h of high-fat but not high-glucose alone, cells decreased AMPK activation and maintained elevated AKT levels. These data were associated to increased cell proliferation after further high-fat treatment. After longer high-fat exposure, MTS revealed that cells remained proliferating. High-glucose alone or associated to high-fat treatment was not able to increase cell proliferation and AKT activation. A high-fat medium containing 100 μM of palmitate stimulates proliferation in PNT1A cells by decreasing the activation of AMPK and increasing activation of AKT after longer exposure time. These findings improve the knowledge about the negative effect of high levels of this saturated fatty acid on proliferative disorders of prostate. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Activation of Liver AMPK with PF-06409577 Corrects NAFLD and Lowers Cholesterol in Rodent and Primate Preclinical Models.

    Science.gov (United States)

    Esquejo, Ryan M; Salatto, Christopher T; Delmore, Jake; Albuquerque, Bina; Reyes, Allan; Shi, Yuji; Moccia, Rob; Cokorinos, Emily; Peloquin, Matthew; Monetti, Mara; Barricklow, Jason; Bollinger, Eliza; Smith, Brennan K; Day, Emily A; Nguyen, Chuong; Geoghegan, Kieran F; Kreeger, John M; Opsahl, Alan; Ward, Jessica; Kalgutkar, Amit S; Tess, David; Butler, Lynne; Shirai, Norimitsu; Osborne, Timothy F; Steinberg, Gregory R; Birnbaum, Morris J; Cameron, Kimberly O; Miller, Russell A

    2018-04-08

    Dysregulation of hepatic lipid and cholesterol metabolism is a significant contributor to cardiometabolic health, resulting in excessive liver lipid accumulation and ultimately non-alcoholic steatohepatitis (NASH). Therapeutic activators of the AMP-Activated Protein Kinase (AMPK) have been proposed as a treatment for metabolic diseases; we show that the AMPK β1-biased activator PF-06409577 is capable of lowering hepatic and systemic lipid and cholesterol levels in both rodent and monkey preclinical models. PF-06409577 is able to inhibit de novo lipid and cholesterol synthesis pathways, and causes a reduction in hepatic lipids and mRNA expression of markers of hepatic fibrosis. These effects require AMPK activity in the hepatocytes. Treatment of hyperlipidemic rats or cynomolgus monkeys with PF-06409577 for 6weeks resulted in a reduction in circulating cholesterol. Together these data suggest that activation of AMPK β1 complexes with PF-06409577 is capable of impacting multiple facets of liver disease and represents a promising strategy for the treatment of NAFLD and NASH in humans. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  3. High Fat Diet Attenuates the Anticontractile Activity of Aortic PVAT via a Mechanism Involving AMPK and Reduced Adiponectin Secretion

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    Tarek A. M. Almabrouk

    2018-02-01

    Full Text Available Background and aim: Perivascular adipose tissue (PVAT positively regulates vascular function through production of factors such as adiponectin but this effect is attenuated in obesity. The enzyme AMP-activated protein kinase (AMPK is present in PVAT and is implicated in mediating the vascular effects of adiponectin. In this study, we investigated the effect of an obesogenic high fat diet (HFD on aortic PVAT and whether any changes involved AMPK.Methods: Wild type Sv129 (WT and AMPKα1 knockout (KO mice aged 8 weeks were fed normal diet (ND or HFD (42% kcal fat for 12 weeks. Adiponectin production by PVAT was assessed by ELISA and AMPK expression studied using immunoblotting. Macrophages in PVAT were identified using immunohistochemistry and markers of M1 and M2 macrophage subtypes evaluated using real time-qPCR. Vascular responses were measured in endothelium-denuded aortic rings with or without attached PVAT. Carotid wire injury was performed and PVAT inflammation studied 7 days later.Key results: Aortic PVAT from KO and WT mice was morphologically indistinct but KO PVAT had more infiltrating macrophages. HFD caused an increased infiltration of macrophages in WT mice with increased expression of the M1 macrophage markers Nos2 and Il1b and the M2 marker Chil3. In WT mice, HFD reduced the anticontractile effect of PVAT as well as reducing adiponectin secretion and AMPK phosphorylation. PVAT from KO mice on ND had significantly reduced adiponectin secretion and no anticontractile effect and feeding HFD did not alter this. Wire injury induced macrophage infiltration of PVAT but did not cause further infiltration in KO mice.Conclusions: High-fat diet causes an inflammatory infiltrate, reduced AMPK phosphorylation and attenuates the anticontractile effect of murine aortic PVAT. Mice lacking AMPKα1 phenocopy many of the changes in wild-type aortic PVAT after HFD, suggesting that AMPK may protect the vessel against deleterious changes in response to

  4. Honokiol activates the LKB1–AMPK signaling pathway and attenuates the lipid accumulation in hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Min Suk; Kim, Jung Hwan; Kim, Hye Jung; Chang, Ki Churl; Park, Sang Won, E-mail: parksw@gnu.ac.kr

    2015-04-15

    Honokiol is a bioactive neolignan compound isolated from the species of Magnolia. This study was designed to elucidate the cellular mechanism by which honokiol alleviates the development of non-alcoholic steatosis. HepG2 cells were treated with honokiol for 1 h, and then exposed to 1 mM free fatty acid (FFA) for 24 h to simulate non-alcoholic steatosis in vitro. C57BL/6 mice were fed with a high-fat diet for 28 days, and honokiol (10 mg/kg/day) was daily treated. Honokiol concentration-dependently attenuated intracellular fat overloading and triglyceride (TG) accumulation in FFA-exposed HepG2 cells. These effects were blocked by pretreatment with an AMP-activated protein kinase (AMPK) inhibitor. Honokiol significantly inhibited sterol regulatory element-binding protein-1c (SREBP-1c) maturation and the induction of lipogenic proteins, stearoyl-CoA desaturase-1 (SCD-1) and fatty acid synthase (FAS) in FFA-exposed HepG2 cells, but these effects were blocked by pretreatment of an AMPK inhibitor. Honokiol induced AMPK phosphorylation and subsequent acetyl-CoA carboxylase (ACC) phosphorylation, which were inhibited by genetic deletion of liver kinase B1 (LKB1). Honokiol stimulated LKB1 phosphorylation, and genetic deletion of LKB1 blocked the effect of honokiol on SREBP-1c maturation and the induction of SCD-1 and FAS proteins in FFA-exposed HepG2 cells. Honokiol attenuated the increases in hepatic TG and lipogenic protein levels and fat accumulation in the mice fed with high-fat diet, while significantly induced LKB1 and AMPK phosphorylation. Taken together, our findings suggest that honokiol has an anti-lipogenic effect in hepatocytes, and this effect may be mediated by the LKB1–AMPK signaling pathway, which induces ACC phosphorylation and inhibits SREBP-1c maturation in hepatocytes. - Highlights: • Honokiol attenuates lipid accumulation induced by free fatty acid in hepatocyte. • Honokiol inhibits the increase in lipogenic enzyme levels induced by free fatty

  5. Honokiol activates the LKB1–AMPK signaling pathway and attenuates the lipid accumulation in hepatocytes

    International Nuclear Information System (INIS)

    Seo, Min Suk; Kim, Jung Hwan; Kim, Hye Jung; Chang, Ki Churl; Park, Sang Won

    2015-01-01

    Honokiol is a bioactive neolignan compound isolated from the species of Magnolia. This study was designed to elucidate the cellular mechanism by which honokiol alleviates the development of non-alcoholic steatosis. HepG2 cells were treated with honokiol for 1 h, and then exposed to 1 mM free fatty acid (FFA) for 24 h to simulate non-alcoholic steatosis in vitro. C57BL/6 mice were fed with a high-fat diet for 28 days, and honokiol (10 mg/kg/day) was daily treated. Honokiol concentration-dependently attenuated intracellular fat overloading and triglyceride (TG) accumulation in FFA-exposed HepG2 cells. These effects were blocked by pretreatment with an AMP-activated protein kinase (AMPK) inhibitor. Honokiol significantly inhibited sterol regulatory element-binding protein-1c (SREBP-1c) maturation and the induction of lipogenic proteins, stearoyl-CoA desaturase-1 (SCD-1) and fatty acid synthase (FAS) in FFA-exposed HepG2 cells, but these effects were blocked by pretreatment of an AMPK inhibitor. Honokiol induced AMPK phosphorylation and subsequent acetyl-CoA carboxylase (ACC) phosphorylation, which were inhibited by genetic deletion of liver kinase B1 (LKB1). Honokiol stimulated LKB1 phosphorylation, and genetic deletion of LKB1 blocked the effect of honokiol on SREBP-1c maturation and the induction of SCD-1 and FAS proteins in FFA-exposed HepG2 cells. Honokiol attenuated the increases in hepatic TG and lipogenic protein levels and fat accumulation in the mice fed with high-fat diet, while significantly induced LKB1 and AMPK phosphorylation. Taken together, our findings suggest that honokiol has an anti-lipogenic effect in hepatocytes, and this effect may be mediated by the LKB1–AMPK signaling pathway, which induces ACC phosphorylation and inhibits SREBP-1c maturation in hepatocytes. - Highlights: • Honokiol attenuates lipid accumulation induced by free fatty acid in hepatocyte. • Honokiol inhibits the increase in lipogenic enzyme levels induced by free fatty

  6. Leptin Boosts Cellular Metabolism by Activating AMPK and the Sirtuins to Reduce Tau Phosphorylation and β-Amyloid in Neurons

    Science.gov (United States)

    Greco, Steven J.; Hamzelou, Ashkan; Johnston, Jane M.; Smith, Mark A.; Ashford, J. Wesson; Tezapsidis, Nikolaos

    2011-01-01

    Leptin is a pleiotropic hormone primarily secreted by adipocytes. A high density of functional Leptin receptors has been reported to be expressed in the hippocampus and other cortical regions of the brain, the physiological significance of which has not been explored extensively. Alzheimer’s disease (AD) is marked by impaired brain metabolism with decreased glucose utilization in those regions which often precede pathological changes. Recent epidemiological studies suggest that plasma Leptin is protective against AD. Specifically, elderly with plasma Leptin levels in the lowest quartile were found to be four times more likely to develop AD than those in the highest quartile. We have previously reported that Leptin modulates AD pathological pathways in vitro through a mechanism involving the energy sensor, AMP-activated protein kinase (AMPK). To this end, we investigated the extent to which activation of AMPK as well as another class of sensors linking energy availability to cellular metabolism, the sirtuins (SIRT), mediate Leptin’s biological activity. Leptin directly activated neuronal AMPK and SIRT in cell lines. Additionally, the ability of Leptin to reduce tau phosphorylation and β-amyloid production was sensitive to the AMPK and sirtuin inhibitors, compound C and nicotinamide, respectively. These findings implicate that Leptin normally acts as a signal for energy homeostasis in neurons. Perhaps Leptin deficiency in AD contributes to a neuronal imbalance in handling energy requirements, leading to higher Aβ and phospho-tau, which can be restored by replenishing low Leptin levels. This may also be a legitimate strategy for therapy. PMID:21945934

  7. AMP-activated protein kinase (AMPK) {beta}1{beta}2 muscle null mice reveal an essential role for AMPK in maintaining mitochondrial content and glucose uptake during exercise

    DEFF Research Database (Denmark)

    O'Neill, Hayley M; Maarbjerg, Stine Just; Crane, Justin D

    2011-01-01

    of AMPK subunits in whole-body AMPK a2, ß2, and ¿3 null mice has made it difficult to determine the physiological importance of AMPK in regulating muscle metabolism, because these models have normal mitochondrial content, contraction-stimulated glucose uptake, and insulin sensitivity. In the current study......, we generated mice lacking both AMPK ß1 and ß2 isoforms in skeletal muscle (ß1ß2M-KO). ß1ß2M-KO mice are physically inactive and have a drastically impaired capacity for treadmill running that is associated with reductions in skeletal muscle mitochondrial content but not a fiber-type switch....... Interestingly, young ß1ß2M-KO mice fed a control chow diet are not obese or insulin resistant but do have impaired contraction-stimulated glucose uptake. These data demonstrate an obligatory role for skeletal muscle AMPK in maintaining mitochondrial capacity and contraction-stimulated glucose uptake, findings...

  8. Effect of resistance exercise under conditions of reduced blood insulin on AMPKα Ser485/491 inhibitory phosphorylation and AMPK pathway activation.

    Science.gov (United States)

    Kido, Kohei; Yokokawa, Takumi; Ato, Satoru; Sato, Koji; Fujita, Satoshi

    2017-08-01

    Insulin stimulates skeletal muscle glucose uptake via activation of the protein kinase B/Akt (Akt) pathway. Recent studies suggest that insulin downregulates AMP-activated protein kinase (AMPK) activity via Ser485/491 phosphorylation of the AMPK α-subunit. Thus lower blood insulin concentrations may induce AMPK signal activation. Acute exercise is one method to stimulate AMPK activation; however, no study has examined the relationship between blood insulin levels and acute resistance exercise-induced AMPK pathway activation. Based on previous findings, we hypothesized that the acute resistance exercise-induced AMPK pathway activation would be augmented by disruptions in insulin secretion through a decrease in AMPKα Ser485/491 inhibitory phosphorylation. To test the hypothesis, 10-wk-old male Sprague-Dawley rats were administered the toxin streptozotocin (STZ; 55 mg/kg) to destroy the insulin secreting β-cells. Three days postinjection, the right gastrocnemius muscle from STZ and control rats was subjected to resistance exercise by percutaneous electrical stimulation. Animals were killed 0, 1, or 3 h later; activation of the Akt/AMPK and downstream pathways in the muscle tissue was analyzed by Western blotting and real-time PCR. Notably, STZ rats showed a significant decrease in basal Akt and AMPKα Ser485/491 phosphorylation, but substantial exercise-induced increases in both AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79 phosphorylation were observed. Although no significant impact on resistance exercise-induced Akt pathway activation or glucose uptake was found, resistance exercise-induced peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 α (PGC-1α) gene expression was augmented by STZ treatment. Collectively, these data suggest that circulating insulin levels may regulate acute resistance exercise-induced AMPK pathway activation and AMPK-dependent gene expression relating to basal AMPKα Ser485/491 phosphorylation. Copyright © 2017

  9. Prolyl isomerase Pin1 negatively regulates AMP-activated protein kinase (AMPK) by associating with the CBS domain in the γ subunit.

    Science.gov (United States)

    Nakatsu, Yusuke; Iwashita, Misaki; Sakoda, Hideyuki; Ono, Hiraku; Nagata, Kengo; Matsunaga, Yasuka; Fukushima, Toshiaki; Fujishiro, Midori; Kushiyama, Akifumi; Kamata, Hideaki; Takahashi, Shin-Ichiro; Katagiri, Hideki; Honda, Hiroaki; Kiyonari, Hiroshi; Uchida, Takafumi; Asano, Tomoichiro

    2015-10-02

    AMP-activated protein kinase (AMPK) plays a critical role in metabolic regulation. In this study, first, it was revealed that Pin1 associates with any isoform of γ, but not with either the α or the β subunit, of AMPK. The association between Pin1 and the AMPK γ1 subunit is mediated by the WW domain of Pin1 and the Thr(211)-Pro-containing motif located in the CBS domain of the γ1 subunit. Importantly, overexpression of Pin1 suppressed AMPK phosphorylation in response to either 2-deoxyglucose or biguanide stimulation, whereas Pin1 knockdown by siRNAs or treatment with Pin1 inhibitors enhanced it. The experiments using recombinant Pin1, AMPK, LKB1, and PP2C proteins revealed that the protective effect of AMP against PP2C-induced AMPKα subunit dephosphorylation was markedly suppressed by the addition of Pin1. In good agreement with the in vitro data, the level of AMPK phosphorylation as well as the expressions of mitochondria-related genes, such as PGC-1α, which are known to be positively regulated by AMPK, were markedly higher with reduced triglyceride accumulation in the muscles of Pin1 KO mice as compared with controls. These findings suggest that Pin1 plays an important role in the pathogenic mechanisms underlying impaired glucose and lipid metabolism, functioning as a negative regulator of AMPK. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Diabetes-Related Ankyrin Repeat Protein (DARP/Ankrd23 Modifies Glucose Homeostasis by Modulating AMPK Activity in Skeletal Muscle.

    Directory of Open Access Journals (Sweden)

    Yoshiaki Shimoda

    Full Text Available Skeletal muscle is the major site for glucose disposal, the impairment of which closely associates with the glucose intolerance in diabetic patients. Diabetes-related ankyrin repeat protein (DARP/Ankrd23 is a member of muscle ankyrin repeat proteins, whose expression is enhanced in the skeletal muscle under diabetic conditions; however, its role in energy metabolism remains poorly understood. Here we report a novel role of DARP in the regulation of glucose homeostasis through modulating AMP-activated protein kinase (AMPK activity. DARP is highly preferentially expressed in skeletal muscle, and its expression was substantially upregulated during myotube differentiation of C2C12 myoblasts. Interestingly, DARP-/- mice demonstrated better glucose tolerance despite similar body weight, while their insulin sensitivity did not differ from that in wildtype mice. We found that phosphorylation of AMPK, which mediates insulin-independent glucose uptake, in skeletal muscle was significantly enhanced in DARP-/- mice compared to that in wildtype mice. Gene silencing of DARP in C2C12 myotubes enhanced AMPK phosphorylation, whereas overexpression of DARP in C2C12 myoblasts reduced it. Moreover, DARP-silencing increased glucose uptake and oxidation in myotubes, which was abrogated by the treatment with AICAR, an AMPK activator. Of note, improved glucose tolerance in DARP-/- mice was abolished when mice were treated with AICAR. Mechanistically, gene silencing of DARP enhanced protein expression of LKB1 that is a major upstream kinase for AMPK in myotubes in vitro and the skeletal muscle in vivo. Together with the altered expression under diabetic conditions, our data strongly suggest that DARP plays an important role in the regulation of glucose homeostasis under physiological and pathological conditions, and thus DARP is a new therapeutic target for the treatment of diabetes mellitus.

  11. Acanthoic acid protectsagainst ethanol-induced liver injury: Possible role of AMPK activation and IRAK4 inhibition.

    Science.gov (United States)

    Yao, You-Li; Han, Xin; Song, Jian; Zhang, Jing; Li, Ya-Mei; Lian, Li-Hua; Wu, Yan-Ling; Nan, Ji-Xing

    2017-11-05

    The aim of this study was to investigate the effects of acanthoic acid (AA) on the regulation of inflammatory response, lipid accumulation, and fibrosis via AMPK- IRAK4 signaling against chronic alcohol consumption in mice. Ethanol-induced liver injury was induced in male mice by Lieber-DeCarli diet for 28d. And mice in AA groups were gavaged with AA (20 or 40mg/kg) for 28d. AA treatment significantly decreased serum AST and TG, hepatic TG levels, serum ethanol and LPS levels compared with chronic ethanol administration. AA ameliorated histological changes, lipid droplets, hepatic fibrosis, and inflammation induced by ethanol. AA significantly increased the expressions of p-LKB1, p-AMPK, and SIRT1 caused by chronic ethanol administration, and attenuated the increasing protein expressions of IRAK1 and IRAK4.siRNA against AMPKα1 blocked AMPKα1 and increased IRAK4 protein expressions, compared with control-siRNA-transfected group, while AA treatment significantly decreased IRAK4 expressions compared with AMPKα1-siRNA-transfected group. AMPK-siRNA also blocked the decreased effect of AA on inflammatory factors. AA decreased over-expression of IRAK4 and inflammation under ethanol plus LPS challenge. AA recruited LKB1-AMPK phosphorylation and activated SIRT1 to regulate alcoholic liver injury, especially, inhibited IRAK1/4 signaling pathway to regulate lipid metabolism, hepatic fibrosis and inflammation caused by alcohol consumption. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. AMPK modulatory activity of olive-tree leaves phenolic compounds: Bioassay-guided isolation on adipocyte model and in silico approach.

    Science.gov (United States)

    Jiménez-Sánchez, Cecilia; Olivares-Vicente, Mariló; Rodríguez-Pérez, Celia; Herranz-López, María; Lozano-Sánchez, Jesús; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto; Encinar, José Antonio; Micol, Vicente

    2017-01-01

    Olive-tree polyphenols have demonstrated potential for the management of obesity-related pathologies. We aimed to explore the capacity of Olive-tree leaves extract to modulate triglyceride accumulation and AMP-activated protein kinase activity (AMPK) on a hypertrophic adipocyte model. Intracellular triglycerides and AMPK activity were measured on the hypertrophic 3T3-L1 adipocyte model by AdipoRed and immunofluorescence microscopy, respectively. Reverse phase high performance liquid chromatography coupled to time-of-flight mass detection with electrospray ionization (RP-HPLC-ESI-TOF/MS) was used for the fractionation of the extract and the identification of the compounds. In-silico molecular docking of the AMPK alpha-2, beta and gamma subunits with the identified compounds was performed. Olive-tree leaves extract decreased the intracellular lipid accumulation through AMPK-dependent mechanisms in hypertrophic adipocytes. Secoiridoids, cinnamic acids, phenylethanoids and phenylpropanoids, flavonoids and lignans were the candidates predicted to account for this effect. Molecular docking revealed that some compounds may be AMPK-gamma modulators. The modulatory effects of compounds over the alpha and beta AMPK subunits appear to be less probable. Olive-tree leaves polyphenols modulate AMPK activity, which may become a therapeutic aid in the management of obesity-associated disturbances. The natural occurrence of these compounds may have important nutritional implications for the design of functional ingredients.

  13. AMPK modulatory activity of olive–tree leaves phenolic compounds: Bioassay-guided isolation on adipocyte model and in silico approach

    Science.gov (United States)

    Jiménez-Sánchez, Cecilia; Olivares-Vicente, Mariló; Rodríguez-Pérez, Celia; Herranz-López, María; Lozano-Sánchez, Jesús; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto; Encinar, José Antonio; Micol, Vicente

    2017-01-01

    Scope Olive-tree polyphenols have demonstrated potential for the management of obesity-related pathologies. We aimed to explore the capacity of Olive-tree leaves extract to modulate triglyceride accumulation and AMP-activated protein kinase activity (AMPK) on a hypertrophic adipocyte model. Methods Intracellular triglycerides and AMPK activity were measured on the hypertrophic 3T3-L1 adipocyte model by AdipoRed and immunofluorescence microscopy, respectively. Reverse phase high performance liquid chromatography coupled to time-of-flight mass detection with electrospray ionization (RP-HPLC-ESI-TOF/MS) was used for the fractionation of the extract and the identification of the compounds. In-silico molecular docking of the AMPK alpha-2, beta and gamma subunits with the identified compounds was performed. Results Olive-tree leaves extract decreased the intracellular lipid accumulation through AMPK-dependent mechanisms in hypertrophic adipocytes. Secoiridoids, cinnamic acids, phenylethanoids and phenylpropanoids, flavonoids and lignans were the candidates predicted to account for this effect. Molecular docking revealed that some compounds may be AMPK-gamma modulators. The modulatory effects of compounds over the alpha and beta AMPK subunits appear to be less probable. Conclusions Olive-tree leaves polyphenols modulate AMPK activity, which may become a therapeutic aid in the management of obesity-associated disturbances. The natural occurrence of these compounds may have important nutritional implications for the design of functional ingredients. PMID:28278224

  14. Comparison of the gastrointestinal absorption and bioavailability of fenofibrate and fenofibric acid in humans.

    Science.gov (United States)

    Zhu, Tong; Ansquer, Jean-Claude; Kelly, Maureen T; Sleep, Darryl J; Pradhan, Rajendra S

    2010-08-01

    This study compared the gastrointestinal (GI) absorption characteristics and absolute bioavailability of fenofibric acid and fenofibrate (which is converted to fenofibric acid in vivo) in healthy volunteers. Treatments were delivered to the proximal small bowel, distal small bowel, and colon using a site-specific delivery system (Enterion capsule) and to the stomach by oral administration of equimolar doses. Serial blood samples were collected for 120 hours postdose and assayed for plasma fenofibric acid concentrations. The absolute bioavailability of each treatment was determined relative to 50 mg of fenofibric acid administered intravenously. Plasma exposure to fenofibric acid following fenofibric acid administration was approximately 1.5 times higher than that following fenofibrate administration for delivery to the proximal and distal small bowel and following oral administration, and it was approximately 5 times higher following colon delivery. The absolute bioavailability in the stomach, proximal small bowel, distal small bowel, and colon was approximately 81%, 88%, 84%, and 78%, respectively, for fenofibric acid and 69%, 73%, 66%, and 22%, respectively, for fenofibrate (P < .0001 and P = .033 for fenofibric acid vs fenofibrate in the colon and distal small bowel, respectively). In conclusion, fenofibric acid is well absorbed throughout the GI tract and has greater bioavailability than fenofibrate in all GI regions.

  15. DENV up-regulates the HMG-CoA reductase activity through the impairment of AMPK phosphorylation: A potential antiviral target.

    Directory of Open Access Journals (Sweden)

    Rubén Soto-Acosta

    2017-04-01

    Full Text Available Dengue is the most common mosquito-borne viral disease in humans. Changes of lipid-related metabolites in endoplasmic reticulum of dengue virus (DENV infected cells have been associated with replicative complexes formation. Previously, we reported that DENV infection inhibits HMGCR phosphorylation generating a cholesterol-enriched cellular environment in order to favor viral replication. In this work, using enzymatic assays, ELISA, and WB we found a significant higher activity of HMGCR in DENV infected cells, associated with the inactivation of AMPK. AMPK activation by metformin declined the HMGCR activity suggesting that AMPK inactivation mediates the enhanced activity of HMGCR. A reduction on AMPK phosphorylation activity was observed in DENV infected cells at 12 and 24 hpi. HMGCR and cholesterol co-localized with viral proteins NS3, NS4A and E, suggesting a role for HMGCR and AMPK activity in the formation of DENV replicative complexes. Furthermore, metformin and lovastatin (HMGCR inhibitor altered this co-localization as well as replicative complexes formation supporting that active HMGCR is required for replicative complexes formation. In agreement, metformin prompted a significant dose-dependent antiviral effect in DENV infected cells, while compound C (AMPK inhibitor augmented the viral genome copies and the percentage of infected cells. The PP2A activity, the main modulating phosphatase of HMGCR, was not affected by DENV infection. These data demonstrate that the elevated activity of HMGCR observed in DENV infected cells is mediated through AMPK inhibition and not by increase in PP2A activity. Interestingly, the inhibition of this phosphatase showed an antiviral effect in an HMGCR-independent manner. These results suggest that DENV infection increases HMGCR activity through AMPK inactivation leading to higher cholesterol levels in endoplasmic reticulum necessary for replicative complexes formation. This work provides new information

  16. Glucose-induced repression of PPARalpha gene expression in pancreatic beta-cells involves PP2A activation and AMPK inactivation

    DEFF Research Database (Denmark)

    Ravnskjaer, Kim; Boergesen, Michael; Dalgaard, Louise T

    2006-01-01

    , the mechanism underlying this transcriptional repression by glucose remains unclear. Here we report that glucose-induced repression of PPARalpha gene expression in INS-1E cells is independent of beta-cell excitation and insulin secretion but requires activation of protein phosphatase 2A in a process involving...... but not AMPKalpha1 using RNAi suppressed PPARalpha expression, thereby mimicking the effect of glucose. These results indicate that activation of protein phosphatase 2A and subsequent inactivation of AMPK is necessary for glucose repression of PPARalpha expression in pancreatic beta-cells....... inactivation of the AMP-activated protein kinase (AMPK). Pharmacological activation of AMPK at high glucose concentrations interferes with glucose repression of PPARalpha and PPARalpha target genes in INS-1E cells as well as in rat islets. Specific knock-down of the catalytic AMPK-subunit AMPKalpha2...

  17. The AMPK activator R419 improves exercise capacity and skeletal muscle insulin sensitivity in obese mice

    Directory of Open Access Journals (Sweden)

    Katarina Marcinko

    2015-09-01

    Conclusions: Treatment of obese mice with R419 improved skeletal muscle insulin sensitivity through a mechanism that is independent of skeletal muscle AMPK. R419 also increases exercise capacity and improves mitochondrial function in obese WT mice; effects that are diminished in the absence of skeletal muscle AMPK. These findings suggest that R419 may be a promising therapy for improving whole-body glucose homeostasis and exercise capacity.

  18. Adenosine monophosphate activated protein kinase (AMPK), a mediator of estradiol-induced apoptosis in long-term estrogen deprived breast cancer cells.

    Science.gov (United States)

    Chen, Haiyan; Wang, Ji-Ping; Santen, Richard J; Yue, Wei

    2015-06-01

    Estrogens stimulate growth of hormone-dependent breast cancer but paradoxically induce tumor regress under certain circumstances. We have shown that long-term estrogen deprivation (LTED) enhances the sensitivity of hormone dependent breast cancer cells to estradiol (E2) so that physiological concentrations of estradiol induce apoptosis in these cells. E2-induced apoptosis involve both intrinsic and extrinsic pathways but precise mechanisms remain unclear. We found that exposure of LTED MCF-7 cells to E2 activated AMP activated protein kinase (AMPK). In contrast, E2 inhibited AMPK activation in wild type MCF-7 cells where E2 prevents apoptosis. As a result of AMPK activation, the transcriptional activity of FoxO3, a downstream factor of AMPK, was up-regulated in E2 treatment of LTED. Increased activity of FoxO3 was demonstrated by up-regulation of three FoxO3 target genes, Bim, Fas ligand (FasL), and Gadd45α. Among them, Bim and FasL mediate intrinsic and extrinsic apoptosis respectively and Gadd45α causes cell cycle arrest at the G2/M phase. To further confirm the role of AMPK in apoptosis, we used AMPK activator AICAR in wild type MCF-7 cells and examined apoptosis, proliferation and expression of Bim, FasL, and Gadd45α. The effects of AICAR on these parameters recapitulated those observed in E2-treated LTED cells. Activation of AMPK by AICAR also increased expression of Bax in MCF-7 cells and its localization to mitochondria, which is a required process for apoptosis. These results reveal that AMPK is an important factor mediating E2-induced apoptosis in LTED cells, which is implicative of therapeutic potential for relapsing breast cancer after hormone therapy.

  19. Arctigenin Inhibits Adipogenesis by Inducing AMPK Activation and Reduces Weight Gain in High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    Han, Yo-Han; Kee, Ji-Ye; Park, Jinbong; Kim, Hye-Lin; Jeong, Mi-Young; Kim, Dae-Seung; Jeon, Yong-Deok; Jung, Yunu; Youn, Dong-Hyun; Kang, JongWook; So, Hong-Seob; Park, Raekil; Lee, Jong-Hyun; Shin, Soyoung; Kim, Su-Jin; Um, Jae-Young; Hong, Seung-Heon

    2016-09-01

    Although arctigenin (ARC) has been reported to have some pharmacological effects such as anti-inflammation, anti-cancer, and antioxidant, there have been no reports on the anti-obesity effect of ARC. The aim of this study is to investigate whether ARC has an anti-obesity effect and mediates the AMP-activated protein kinase (AMPK) pathway. We investigated the anti-adipogenic effect of ARC using 3T3-L1 pre-adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). In high-fat diet (HFD)-induced obese mice, whether ARC can inhibit weight gain was investigated. We found that ARC reduced weight gain, fat pad weight, and triglycerides in HFD-induced obese mice. ARC also inhibited the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in in vitro and in vivo. Furthermore, ARC induced the AMPK activation resulting in down-modulation of adipogenesis-related factors including PPARγ, C/EBPα, fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase. This study demonstrates that ARC can reduce key adipogenic factors by activating the AMPK in vitro and in vivo and suggests a therapeutic implication of ARC for obesity treatment. J. Cell. Biochem. 117: 2067-2077, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. microRNA-135b expression silences Ppm1e to provoke AMPK activation and inhibit osteoblastoma cell proliferation.

    Science.gov (United States)

    Li, Zheng-Wei; Zhu, Yun-Rong; Zhou, Xiao-Zhong; Zhuo, Bao-Biao; Wang, Xiao-Dong

    2017-04-18

    Forced-activation of AMP-activated protein kinase (AMPK) can possibly inhibit osteoblastoma cells. Here, we aim to provoke AMPK activation via microRNA silencing its phosphatase Ppm1e (protein phosphatase Mg2+/Mn2+-dependent 1e). We showed that microRNA-135b-5p ("miR-135b-5p"), the anti-Ppm1e microRNA, was significantly downregulated in human osteoblastoma tissues. It was correlated with Ppm1e upregulation and AMPKα1 de-phosphorylation. Forced-expression of miR-135b-5p in human osteoblastoma cells (MG-63 and U2OS lines) silenced Ppm1e, and induced a profound AMPKα1 phosphorylation (at Thr-172). Osteoblastoma cell proliferation was inhibited after miR-135b-5p expression. Intriguingly, Ppm1e shRNA knockdown similarly induced AMPKα1 phosphorylation, causing osteoblastoma cell proliferation. Reversely, AMPKα1 shRNA knockdown or dominant negative mutation almost abolished miR-135b-5p's actions in osteoblastoma cells. Further in vivo studies demonstrated that U2OS tumor growth in mice was dramatically inhibited after expressing miR-135b-5p or Ppm1e shRNA. Together, our results suggest that miR-135b-induced Ppm1e silence induces AMPK activation to inhibit osteoblastoma cell proliferation.

  1. microRNA-135b expression silences Ppm1e to provoke AMPK activation and inhibit osteoblastoma cell proliferation

    Science.gov (United States)

    Li, Zheng-Wei; Zhu, Yun-Rong; Zhou, Xiao-Zhong; Zhuo, Bao-Biao; Wang, Xiao-Dong

    2017-01-01

    Forced-activation of AMP-activated protein kinase (AMPK) can possibly inhibit osteoblastoma cells. Here, we aim to provoke AMPK activation via microRNA silencing its phosphatase Ppm1e (protein phosphatase Mg2+/Mn2+-dependent 1e). We showed that microRNA-135b-5p (“miR-135b-5p”), the anti-Ppm1e microRNA, was significantly downregulated in human osteoblastoma tissues. It was correlated with Ppm1e upregulation and AMPKα1 de-phosphorylation. Forced-expression of miR-135b-5p in human osteoblastoma cells (MG-63 and U2OS lines) silenced Ppm1e, and induced a profound AMPKα1 phosphorylation (at Thr-172). Osteoblastoma cell proliferation was inhibited after miR-135b-5p expression. Intriguingly, Ppm1e shRNA knockdown similarly induced AMPKα1 phosphorylation, causing osteoblastoma cell proliferation. Reversely, AMPKα1 shRNA knockdown or dominant negative mutation almost abolished miR-135b-5p's actions in osteoblastoma cells. Further in vivo studies demonstrated that U2OS tumor growth in mice was dramatically inhibited after expressing miR-135b-5p or Ppm1e shRNA. Together, our results suggest that miR-135b-induced Ppm1e silence induces AMPK activation to inhibit osteoblastoma cell proliferation. PMID:28460435

  2. The 5'-AMP-Activated Protein Kinase (AMPK Is Involved in the Augmentation of Antioxidant Defenses in Cryopreserved Chicken Sperm.

    Directory of Open Access Journals (Sweden)

    Thi Mong Diep Nguyen

    Full Text Available Semen cryopreservation is a unique tool for the management of animal genetic diversity. However, the freeze-thaw process causes biochemical and physical alterations which make difficult the restoration of sperm energy-dependent functions needed for fertilization. 5'-AMP activated protein kinase (AMPK is a key sensor and regulator of intracellular energy metabolism. Mitochondria functions are known to be severely affected during sperm cryopreservation with deleterious oxidative and peroxidative effects leading to cell integrity and functions damages. The aim of this study was thus to examine the role of AMPK on the peroxidation/antioxidant enzymes defense system in frozen-thawed sperm and its consequences on sperm functions. Chicken semen was diluted in media supplemented with or without AMPK activators (AICAR or Metformin [MET] or inhibitor (Compound C [CC] and then cryopreserved. AMPKα phosphorylation, antioxidant enzymes activities, mitochondrial potential, ATP, citrate, viability, acrosome reaction ability (AR and various motility parameters were negatively affected by the freeze-thaw process while reactive oxygen species (ROS production, lipid peroxidation (LPO and lactate concentration were dramatically increased. AICAR partially restored superoxide dismutase (SOD, Glutathione Peroxidase (GPx and Glutathione Reductase (GR, increased ATP, citrate, and lactate concentration and subsequently decreased the ROS and LPO (malondialdehyde in frozen-thawed semen. Motility parameters were increased (i.e., + 23% for motility, + 34% for rapid sperm as well as AR (+ 100%. MET had similar effects as AICAR except that catalase activity was restored and that ATP and mitochondrial potential were further decreased. CC showed effects opposite to AICAR on SOD, ROS, LPO and AR and motility parameters. Taken together, our results strongly suggest that, upon freeze-thaw process, AMPK stimulated intracellular anti-oxidative defense enzymes through ATP regulation

  3. Maternal obesity alters fatty acid oxidation, AMPK activity, and associated DNA methylation in mesenchymal stem cells from human infants.

    Science.gov (United States)

    Boyle, Kristen E; Patinkin, Zachary W; Shapiro, Allison L B; Bader, Carly; Vanderlinden, Lauren; Kechris, Katerina; Janssen, Rachel C; Ford, Rebecca J; Smith, Brennan K; Steinberg, Gregory R; Davidson, Elizabeth J; Yang, Ivana V; Dabelea, Dana; Friedman, Jacob E

    2017-11-01

    Infants born to mothers with obesity have greater adiposity, ectopic fat storage, and are at increased risk for childhood obesity and metabolic disease compared with infants of normal weight mothers, though the cellular mechanisms mediating these effects are unclear. We tested the hypothesis that human, umbilical cord-derived mesenchymal stem cells (MSCs) from infants born to obese (Ob-MSC) versus normal weight (NW-MSC) mothers demonstrate altered fatty acid metabolism consistent with adult obesity. In infant MSCs undergoing myogenesis in vitro, we measured cellular lipid metabolism and AMPK activity, AMPK activation in response to cellular nutrient stress, and MSC DNA methylation and mRNA content of genes related to oxidative metabolism. We found that Ob-MSCs exhibit greater lipid accumulation, lower fatty acid oxidation (FAO), and dysregulation of AMPK activity when undergoing myogenesis in vitro. Further experiments revealed a clear phenotype distinction within the Ob-MSC group where more severe MSC metabolic perturbation corresponded to greater neonatal adiposity and umbilical cord blood insulin levels. Targeted analysis of DNA methylation array revealed Ob-MSC hypermethylation in genes regulating FAO (PRKAG2, ACC2, CPT1A, SDHC) and corresponding lower mRNA content of these genes. Moreover, MSC methylation was positively correlated with infant adiposity. These data suggest that greater infant adiposity is associated with suppressed AMPK activity and reduced lipid oxidation in MSCs from infants born to mothers with obesity and may be an important, early marker of underlying obesity risk. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  4. Long-Term Consumption of Platycodi Radix Ameliorates Obesity and Insulin Resistance via the Activation of AMPK Pathways

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    Chae Eun Lee

    2012-01-01

    Full Text Available This study was designed to evaluate the effects and mechanism of Platycodi radix, having white balloon flower (Platycodon grandiflorum for. albiflorum (Honda H. Hara on obesity and insulin resistance. The extracts of Platycodi radix with white balloon flower were tested in cultured cells and administered into mice on a high-fat diet. The Platycodi radix activated the AMPK/ACC phosphorylation in C2C12 myotubes and also suppressed adipocyte differentiation in 3T3-L1 cells. In experimental animal, it suppressed the weight gain of obese mice and ameliorated obesity-induced insulin resistance. It also reduced the elevated circulating mediators, including triglyceride (TG, T-CHO, leptin, resistin, and monocyte chemotactic protein (MCP-1 in obesity. As shown in C2C12 myotubes, the administration of Platycodi radix extracts also recovered the AMPK/ACC phosphorylation in the muscle of obese mice. These results suggest that Platycodi radix with white balloon flower ameliorates obesity and insulin resistance in obese mice via the activation of AMPK/ACC pathways and reductions of adipocyte differentiation.

  5. Rosmarinic Acid Alleviates the Endothelial Dysfunction Induced by Hydrogen Peroxide in Rat Aortic Rings via Activation of AMPK

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2017-01-01

    Full Text Available Endothelial dysfunction is the key player in the development and progression of vascular events. Oxidative stress is involved in endothelial injury. Rosmarinic acid (RA is a natural polyphenol with antioxidative, antiapoptotic, and anti-inflammatory properties. The present study investigates the protective effect of RA on endothelial dysfunction induced by hydrogen peroxide (H2O2. Compared with endothelium-denuded aortic rings, the endothelium significantly alleviated the decrease of vasoconstrictive reactivity to PE and KCl induced by H2O2. H2O2 pretreatment significantly injured the vasodilative reactivity to ACh in endothelium-intact aortic rings in a concentration-dependent manner. RA individual pretreatment had no obvious effect on the vasoconstrictive reaction to PE and KCl, while its cotreatment obviously mitigated the endothelium-dependent relaxation impairments and the oxidative stress induced by H2O2. The RA cotreatment reversed the downregulation of AMPK and eNOS phosphorylation induced by H2O2 in HAEC cells. The pretreatment with the inhibitors of AMPK (compound C and eNOS (L-NAME wiped off RA’s beneficial effects. All these results demonstrated that RA attenuated the endothelial dysfunction induced by oxidative stress by activating the AMPK/eNOS pathway.

  6. Saponarin activates AMPK in a calcium-dependent manner and suppresses gluconeogenesis and increases glucose uptake via phosphorylation of CRTC2 and HDAC5.

    Science.gov (United States)

    Seo, Woo-Duck; Lee, Ji Hae; Jia, Yaoyao; Wu, Chunyan; Lee, Sung-Joon

    2015-11-15

    This study investigated the molecular mechanism of saponarin, a flavone glucoside, in the regulation of insulin sensitivity. Saponarin suppressed the rate of gluconeogenesis and increased cellular glucose uptake in HepG2 and TE671 cells by regulating AMPK. Using an in vitro kinase assay, we showed that saponarin did not directly interact with the AMPK protein. Instead, saponarin increased intracellular calcium levels and induced AMPK phosphorylation, which was diminished by co-stimulation with STO-609, an inhibitor of CAMKKβ. Transcription of hepatic gluconeogenesis genes was upregulated by nuclear translocation of CRTC2 and HDAC5, coactivators of CREB and FoxO1 transcription factors, respectively. This nuclear translocation was inhibited by increased phosphorylation of CRTC2 and HDAC5 by saponarin-induced AMPK in HepG2 cells and suppression of CREB and FoxO1 transactivation activities in cells stimulated by saponarin. The results from a chromatin immunoprecipitation assay confirmed the reduced binding of CRTC2 on the PEPCK and G6Pase promoters. In TE671 cells, AMPK phosphorylated HDAC5, which suppressed nuclear penetration and upregulated GLUT4 transcription, leading to enhanced glucose uptake. Collectively, these results suggest that saponarin activates AMPK in a calcium-dependent manner, thus regulating gluconeogenesis and glucose uptake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Fenofibrate Administration Reduces Alcohol and Saccharin Intake in Rats: Possible Effects at Peripheral and Central Levels

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    Mario Rivera-Meza

    2017-07-01

    Full Text Available We have previously shown that the administration of fenofibrate to high-drinker UChB rats markedly reduces voluntary ethanol intake. Fenofibrate is a peroxisome proliferator-activated receptor alpha (PPARα agonist, which induces the proliferation of peroxisomes in the liver, leading to increases in catalase levels that result in acetaldehyde accumulation at aversive levels in the blood when animals consume ethanol. In these new studies, we aimed to investigate if the effect of fenofibrate on ethanol intake is produced exclusively in the liver (increasing catalase and systemic levels of acetaldehyde or there might be additional effects at central level. High drinker rats (UChB were allowed to voluntary drink 10% ethanol for 2 months. Afterward, a daily dose of fenofibrate (25, 50 or 100 mg/kg/day or vehicle (as control was administered orally for 14 days. Voluntary ethanol intake was recorded daily. After that time, animals were deprived of ethanol access for 24 h and administered with an oral dose of ethanol (1 g/kg for acetaldehyde determination in blood. Fenofibrate reduced ethanol voluntary intake by 60%, in chronically drinking rats, at the three doses tested. Acetaldehyde in the blood rose up to between 80 μM and 100 μM. Considering the reduction of ethanol consumption, blood acetaldehyde levels and body weight evolution, the better results were obtained at a dose of 50 mg fenofibrate/kg/day. This dose of fenofibrate also reduced the voluntary intake of 0.2% saccharin by 35% and increased catalase levels 2.5-fold in the liver but showed no effects on catalase levels in the brain. To further study if fenofibrate administration changes the motivational properties of ethanol, a conditioned-place preference experiment was carried out. Animals treated with fenofibrate (50 mg/kg/day did not develop ethanol-conditioned place preference (CPP.In an additional experiment, chronically ethanol-drinking rats underwent two cycles of ethanol

  8. Fenofibrate Administration Reduces Alcohol and Saccharin Intake in Rats: Possible Effects at Peripheral and Central Levels

    Science.gov (United States)

    Rivera-Meza, Mario; Muñoz, Daniel; Jerez, Erik; Quintanilla, María E.; Salinas-Luypaert, Catalina; Fernandez, Katia; Karahanian, Eduardo

    2017-01-01

    We have previously shown that the administration of fenofibrate to high-drinker UChB rats markedly reduces voluntary ethanol intake. Fenofibrate is a peroxisome proliferator-activated receptor alpha (PPARα) agonist, which induces the proliferation of peroxisomes in the liver, leading to increases in catalase levels that result in acetaldehyde accumulation at aversive levels in the blood when animals consume ethanol. In these new studies, we aimed to investigate if the effect of fenofibrate on ethanol intake is produced exclusively in the liver (increasing catalase and systemic levels of acetaldehyde) or there might be additional effects at central level. High drinker rats (UChB) were allowed to voluntary drink 10% ethanol for 2 months. Afterward, a daily dose of fenofibrate (25, 50 or 100 mg/kg/day) or vehicle (as control) was administered orally for 14 days. Voluntary ethanol intake was recorded daily. After that time, animals were deprived of ethanol access for 24 h and administered with an oral dose of ethanol (1 g/kg) for acetaldehyde determination in blood. Fenofibrate reduced ethanol voluntary intake by 60%, in chronically drinking rats, at the three doses tested. Acetaldehyde in the blood rose up to between 80 μM and 100 μM. Considering the reduction of ethanol consumption, blood acetaldehyde levels and body weight evolution, the better results were obtained at a dose of 50 mg fenofibrate/kg/day. This dose of fenofibrate also reduced the voluntary intake of 0.2% saccharin by 35% and increased catalase levels 2.5-fold in the liver but showed no effects on catalase levels in the brain. To further study if fenofibrate administration changes the motivational properties of ethanol, a conditioned-place preference experiment was carried out. Animals treated with fenofibrate (50 mg/kg/day) did not develop ethanol-conditioned place preference (CPP).In an additional experiment, chronically ethanol-drinking rats underwent two cycles of ethanol deprivation

  9. Resistance exercise-induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high-intensity interval cycling

    DEFF Research Database (Denmark)

    Apró, William; Moberg, Marcus; Hamilton, D. Lee

    2015-01-01

    was not observed following R exercise only. In conclusion, cycling-induced elevation in AMPK activity does not inhibit mTOR complex 1 signaling after subsequent resistance exercise but may instead interfere with the hypertrophic response by influencing key components in protein breakdown....

  10. Ultraviolet (UV and Hydrogen Peroxide Activate Ceramide-ER Stress-AMPK Signaling Axis to Promote Retinal Pigment Epithelium (RPE Cell Apoptosis

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    Jin Yao

    2013-05-01

    Full Text Available Ultraviolet (UV radiation and reactive oxygen species (ROS impair the physiological functions of retinal pigment epithelium (RPE cells by inducing cell apoptosis, which is the main cause of age-related macular degeneration (AMD. The mechanism by which UV/ROS induces RPE cell death is not fully addressed. Here, we observed the activation of a ceramide-endoplasmic reticulum (ER stress-AMP activated protein kinase (AMPK signaling axis in UV and hydrogen peroxide (H2O2-treated RPE cells. UV and H2O2 induced an early ceramide production, profound ER stress and AMPK activation. Pharmacological inhibitors against ER stress (salubrinal, ceramide production (fumonisin B1 and AMPK activation (compound C suppressed UV- and H2O2-induced RPE cell apoptosis. Conversely, cell permeable short-chain C6 ceramide and AMPK activator AICAR (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide mimicked UV and H2O2’s effects and promoted RPE cell apoptosis. Together, these results suggest that UV/H2O2 activates the ceramide-ER stress-AMPK signaling axis to promote RPE cell apoptosis.

  11. AMPK-sensitive cellular transport.

    Science.gov (United States)

    Dërmaku-Sopjani, Miribane; Abazi, Sokol; Faggio, Caterina; Kolgeci, Jehona; Sopjani, Mentor

    2014-03-01

    The energy sensing AMP-activated protein kinase (AMPK) regulates cellular and whole-body energy balance through stimulating catabolic ATP-generating and suppressing anabolic ATP-consuming pathways thereby helping cells survive during energy depletion. The kinase has previously been reported to be either directly or indirectly involved in the regulation of several carriers, channels and pumps of high significance in cellular physiology. Thus AMPK provides a necessary link between cellular energy metabolism and cellular transport activity. Better understanding of the AMPK role in cellular transport offers a potential for improved therapies in various human diseases and disorders. In this review, we discuss recent advances in understanding the role and function of AMPK in transport regulation under physiological and pathological states.

  12. AMPK regulates metabolism and survival in response to ionizing radiation

    International Nuclear Information System (INIS)

    Zannella, Vanessa E.; Cojocari, Dan; Hilgendorf, Susan; Vellanki, Ravi N.; Chung, Stephen; Wouters, Bradly G.; Koritzinsky, Marianne

    2011-01-01

    Background and purpose: AMPK is a metabolic sensor and an upstream inhibitor of mTOR activity. AMPK is phosphorylated by ionizing radiation (IR) in an ATM dependent manner, but the cellular consequences of this phosphorylation event have remained unclear. The objective of this study was to assess whether AMPK plays a functional role in regulating cellular responses to IR. Methods: The importance of AMPK expression for radiation responses was investigated using both MEFs (mouse embryo fibroblasts) double knockout for AMPK α1/α2 subunits and human colorectal carcinoma cells (HCT 116) with AMPK α1/α2 shRNA mediated knockdown. Results: We demonstrate here that IR results in phosphorylation of both AMPK and its substrate, ACC. IR moderately stimulated mTOR activity, and this was substantially exacerbated in the absence of AMPK. AMPK was required for IR induced expression of the mTOR inhibitor REDD1, indicating that AMPK restrains mTOR activity through multiple mechanisms. Likewise, cellular metabolism was deregulated following irradiation in the absence of AMPK, as evidenced by a substantial increase in oxygen consumption rates and lactate production. AMPK deficient cells showed impairment of the G1/S cell cycle checkpoint, and were unable to support long-term proliferation during starvation following radiation. Lastly, we show that AMPK proficiency is important for clonogenic survival after radiation during starvation. Conclusions: These data reveal novel functional roles for AMPK in regulating mTOR signaling, cell cycle, survival and metabolic responses to IR.

  13. Decreased spontaneous activity in AMPK alpha 2 muscle specific kinase dead mice is not caused by changes in brain dopamine metabolism

    DEFF Research Database (Denmark)

    Møller, Lisbeth Liliendal Valbjørn; Sylow, Lykke; Gøtzsche, Casper René

    2016-01-01

    It is well known that physical activity has several health benefits, yet many people do not exercise. Dopamine levels in the striatum of the brain are thought to be important for the motivation to exercise. Conversely, we hypothesized that muscle quality can affect the motivation to exercise...... DOPAC and HVA were also similar between genotypes. These findings show that decreased AMPK activity in muscle leads to decreased voluntary activity which is not due to secondary abnormalities in dopamine levels in the ventral striatum or sensitivity to cocaine. Thus, decreased voluntary activity in AMPK...

  14. Synergic chemoprevention with dietary carbohydrate restriction and supplementation of AMPK-activating phytochemicals: the role of SIRT1.

    Science.gov (United States)

    Lee, Jong Doo; Choi, Min-Ah; Ro, Simon Weonsang; Yang, Woo Ick; Cho, Arthur E H; Ju, Hye-Lim; Baek, Sinhwa; Chung, Sook In; Kang, Won Jun; Yun, Mijin; Park, Jeon Han

    2016-01-01

    Calorie restriction or a low-carbohydrate diet (LCD) can increase life span in normal cells while inhibiting carcinogenesis. Various phytochemicals also have calorie restriction-mimetic anticancer properties. We investigated whether an isocaloric carbohydrate-restriction diet and AMP-activated protein kinase (AMPK)-activating phytochemicals induce synergic tumor suppression. We used a mixture of AMPK-activating phytochemical extracts including curcumin, quercetin, catechins, and resveratrol. Survival analysis was carried out in a B16F10 melanoma model fed a control diet (62.14% kcal carbohydrate, 24.65% kcal protein and 13.2% kcal fat), a control diet with multiple phytochemicals (MP), LCD (16.5, 55.2, and 28.3% kcal, respectively), LCD with multiple phytochemicals (LCDmp), a moderate-carbohydrate diet (MCD, 31.9, 62.4, and 5.7% kcal, respectively), or MCD with phytochemicals (MCDmp). Compared with the control group, MP, LCD, or MCD intervention did not produce survival benefit, but LCDmp (22.80±1.58 vs. 28.00±1.64 days, P=0.040) and MCDmp (23.80±1.08 vs. 30.13±2.29 days, P=0.008) increased the median survival time significantly. Suppression of the IGF-1R/PI3K/Akt/mTOR signaling, activation of the AMPK/SIRT1/LKB1pathway, and NF-κB suppression were the critical tumor-suppression mechanisms. In addition, SIRT1 suppressed proliferation of the B16F10 and A375SM cells under a low-glucose condition. Alterations in histone methylation within Pten and FoxO3a were observed after the MCDmp intervention. In the transgenic liver cancer model developed by hydrodynamic transfection of the HrasG12V and shp53, MCDmp and LCDmp interventions induced significant cancer-prevention effects. Microarray analysis showed that PPARα increased with decreased IL-6 and NF-κB within the hepatocytes after an MCDmp intervention. In conclusion, an isocaloric carbohydrate-restriction diet and natural AMPK-activating agents induce synergistic anticancer effects. SIRT1 acts as a

  15. Specific deletion of AMP-activated protein kinase (α1AMPK in murine oocytes alters junctional protein expression and mitochondrial physiology.

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    Michael J Bertoldo

    Full Text Available Oogenesis and folliculogenesis are dynamic processes that are regulated by endocrine, paracrine and autocrine signals. These signals are exchanged between the oocyte and the somatic cells of the follicle. Here we analyzed the role of AMP-activated protein kinase (AMPK, an important regulator of cellular energy homeostasis, by using transgenic mice deficient in α1AMPK specifically in the oocyte. We found a decrease of 27% in litter size was observed in ZP3-α1AMPK-/- (ZP3-KO female mice. Following in vitro fertilization, where conditions are stressful for the oocyte and embryo, ZP3-KO oocytes were 68% less likely to pass the 2-cell stage. In vivo and in cumulus-oocyte complexes, several proteins involved in junctional communication, such as connexin37 and N-cadherin were down-regulated in the absence of α1AMPK. While the two signalling pathways (PKA and MAPK involved in the junctional communication between the cumulus/granulosa cells and the oocyte were stimulated in control oocytes, ZP3-KO oocytes exhibited only low phosphorylation of MAPK or CREB proteins. In addition, MII oocytes deficient in α1AMPK had a 3-fold lower ATP concentration, an increase in abnormal mitochondria, and a decrease in cytochrome C and PGC1α levels, suggesting perturbed energy production by mitochondria. The absence of α1AMPK also induced a reduction in histone deacetylase activity, which was associated with an increase in histone H3 acetylation (K9/K14 residues. Together, the results of the present study suggest that absence of AMPK, modifies oocyte quality through energy processes and oocyte/somatic cell communication. The limited effect observed in vivo could be partly due to a favourable follicle microenvironment where nutrients, growth factors, and adequate cell interaction were present. Whereas in a challenging environment such as that of in vitro culture following IVF, the phenotype is revealed.

  16. Fenoterol inhibits LPS-induced AMPK activation and inflammatory cytokine production through β-arrestin-2 in THP-1 cell line

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei [Department of Respiratory Medicine, Peking University Third Hospital, Beijing (China); Department of Infectious Diseases, Peking University Third Hospital, Beijing (China); Zhang, Yuan [Department of Respiratory Medicine, Peking University Third Hospital, Beijing (China); Xu, Ming; Zhang, You-Yi [Department of Institute of Vascular Medicine and Beijing Key Laboratory of Cardiovascular Receptors Research, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Peking University Third Hospital, Beijing (China); He, Bei, E-mail: puh3_hb@bjmu.edu.cn [Department of Respiratory Medicine, Peking University Third Hospital, Beijing (China)

    2015-06-26

    The AMP-activated protein kinase (AMPK) pathway is involved in regulating inflammation in several cell lines. We reported that fenoterol, a β{sub 2}-adrenergic receptor (β{sub 2}-AR) agonist, had anti-inflammatory effects in THP-1 cells, a monocytic cell line. Whether the fenoterol anti-inflammatory effect involves the AMPK pathway is unknown. In this study, we explored the mechanism of β{sub 2}-AR stimulation with fenoterol in a lipopolysaccharide (LPS)-induced inflammatory cytokine secretion in THP-1 cells. We studied whether fenoterol and β-arrestin-2 or AMPKα1 subunit knockdown could affect LPS-induced AMPK activation, nuclear factor-kappa B (NF-κB) activation and inflammatory cytokine secretion. LPS-induced AMPK activation and interleukin 1β (IL-1β) release were reduced with fenoterol pretreatment of THP-1 cells. SiRNA knockdown of β-arrestin-2 abolished the fenoterol inhibition of LPS-induced AMPK activation and interleukin 1β (IL-1β) release, thus β-arrestin-2 mediated the anti-inflammatory effects of fenoterol on LPS-treated THP-1 cells. In addition, siRNA knockdown of AMPKα1 significantly attenuated the LPS-induced NF-κB activation and IL-1β release, so AMPKα1 was a key signaling molecule involved in LPS-induced inflammatory cytokine production. These results suggested the β{sub 2}-AR agonist fenoterol inhibited LPS-induced AMPK activation and IL-1β release via β-arrestin-2 in THP-1 cells. The exploration of these mechanisms may help optimize therapeutic agents targeting these pathways in inflammatory diseases. - Highlights: • β{sub 2}-AR agonist fenoterol exerts its protective effect on LPS-treated THP-1 cells. • Fenoterol inhibits LPS-induced AMPK activation and IL-1β production. • β-arrestin2 mediates fenoterol-inhibited AMPK activation and IL-1β release. • AMPKα1 is involved in LPS-induced NF-κB activation and IL-1β production.

  17. Alamandine acts via MrgD to induce AMPK/NO activation against Ang II hypertrophy in cardiomyocytes.

    Science.gov (United States)

    de Jesus, Itamar Couto Guedes; Scalzo, Sergio; Alves, Fabiana; Marques, Kariny; Rocha-Resende, Cibele; Bader, Michael; Santos, Robson A Souza; Guatimosim, Silvia

    2018-02-14

    The renin-angiotensin system (RAS) plays a pivotal role in the pathogenesis of cardiovascular diseases. New members of this system have been characterized and shown to have biologically relevant actions. Alamandine and its receptor MrgD are recently identified components of RAS. In the cardiovascular system alamandine actions included vasodilation, antihypertensive and anti-fibrosis effects. Currently, the actions of alamandine on cardiomyocytes are unknown. Here our goal was twofold: (1) to unravel the signaling molecules activated by the alamandine/MrgD axis in cardiomyocytes; (2) to evaluate the ability of this axis to prevent against Angiotensin II (Ang II)-induced hypertrophy. In cardiomyocytes from C57BL/6 mice, alamandine treatment induced an increase in nitric oxide (NO) production, which was blocked by D-Pro 7 -Ang-(1-7), a MrgD antagonist. This NO rise correlated with increased phosphorylation of AMPK. Alamandine induced NO production was preserved in Mas -/- myocytes, and lost in MrgD -/- cells. Binding of fluorescent-labeled alamandine was observed in wild-type cells, but it was dramatically reduced in MrgD -/- myocytes. We also assessed the consequences of prolonged alamandine exposure to cultured neonatal rat cardiomyocytes (NRCMs) treated with Ang II. Treatment of NRCMs with alamandine prevented Ang II-induced hypertrophy. Moreover, antihypertrophic actions of alamandine were mediated via MrgD and NO, since they could be prevented by D-Pro 7 -Ang-(1-7) or inhibitors of NO synthase or AMPK. β-alanine, a MrgD agonist, recapitulated alamandine's cardioprotective effects in cardiomyocytes. Our data show that alamandine via MrgD induces AMPK/NO signaling to counterregulate Ang II induced hypertrophy. These findings highlight the therapeutic potential of the alamandine/MrgD axis in the heart.

  18. Serum Is Not Necessary for Prior Pharmacological Activation of AMPK to Increase Insulin Sensitivity of Mouse Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Nicolas O. Jørgensen

    2018-04-01

    Full Text Available Exercise, contraction, and pharmacological activation of AMP-activated protein kinase (AMPK by 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR have all been shown to increase muscle insulin sensitivity for glucose uptake. Intriguingly, improvements in insulin sensitivity following contraction of isolated rat and mouse skeletal muscle and prior AICAR stimulation of isolated rat skeletal muscle seem to depend on an unknown factor present in serum. One study recently questioned this requirement of a serum factor by showing serum-independency with muscle from old rats. Whether a serum factor is necessary for prior AICAR stimulation to increase insulin sensitivity of mouse skeletal muscle is not known. Therefore, we investigated the necessity of serum for this effect of AICAR in mouse skeletal muscle. We found that the ability of prior AICAR stimulation to improve insulin sensitivity of mouse skeletal muscle did not depend on the presence of serum during AICAR stimulation. Although prior AICAR stimulation did not enhance proximal insulin signaling, insulin-stimulated phosphorylation of Tre-2/BUB2/CDC16- domain family member 4 (TBC1D4 Ser711 was greater in prior AICAR-stimulated muscle compared to all other groups. These results imply that the presence of a serum factor is not necessary for prior AMPK activation by AICAR to enhance insulin sensitivity of mouse skeletal muscle.

  19. Expression of adenosine 5'-monophosphate-Activated protein kinase (AMPK) in ovine testis (Ovis aries): In vivo regulation by nutritional state.

    Science.gov (United States)

    Taibi, N; Dupont, J; Bouguermouh, Z; Froment, P; Ramé, C; Anane, A; Amirat, Z; Khammar, F

    2017-03-01

    In the present study, we identified AMPK and investigated its potential role in steroidogenesis in vivo in the ovine testis in response to variation in nutritional status (fed control vs. restricted). We performed immunoblotting to show that both active and non-active forms of AMPK exist in ovine testis and liver. In testis, we confirmed these results by immunohistochemistry. We found a correlation between ATP (Adenosine-Triphosphate) levels and the expression of AMPK in liver. Also, low and high caloric diets induce isoform-dependent AMPK expression, with an increase in α2, ß1ß2 and γ1 activity levels. Although the restricted group exhibited an increase in lipid balance, only the triglyceride and HC-VLDL (Cholesterol-Very low density lipoprotein) fractions showed significant differences between groups, suggesting an adaptive mechanism. Moreover, the relatively low rate of non-esterified fatty acid released into the circulation implies re-esterification to compensate for the physiological need. In the fed control group, AMPK activates the production of testosterone in Leydig cells; this is, in turn, associated with an increase in the expression of 3ß-HSD (3 beta hydroxy steroid deshydrogenase), p450scc (Cholesterol side-chain cleavage enzyme) and StAR (Steroidogenic acute regulatory protein) proteins induced by decreased MAPK ERK½ (Extracellular signal-regulated kinase -Mitogen-activated protein kinase) phosphorylation. In contrast, in the restricted group, testosterone secretion was reduced but intracellular cholesterol concentration was not. Furthermore, the combination of high levels of lipoproteins and emergence of the p38 MAP kinase pathway suggest the involvement of pro-inflammatory cytokines, as confirmed by transcriptional repression of the StAR protein. Taken together, these results suggest that AMPK expression is tissue dependent. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Reduction of lipid accumulation in white adipose tissues by Cassia tora (Leguminosae) seed extract is associated with AMPK activation.

    Science.gov (United States)

    Tzeng, Thing-Fong; Lu, Hung-Jen; Liou, Shorong-Shii; Chang, Chia Ju; Liu, I-Min

    2013-01-15

    Natural herbal medications may be one answer to the worldwide epidemic of obesity. This study examines the effects of Cassia seed ethanol extract (CSEE) upon lipid accumulation in white adipose tissue (WAT). CSEE exhibited a significant concentration-dependent decrease in the intracellular accumulation of trigycerides in 3T3-L1 adipocytes. After being fed a high-fat diet (HFD) for 2 weeks, rats were fed CSEE (100, 200 or 300 mg/kg) once daily for 8 weeks. CSEE caused dose-related reductions in body weight gain (as well as plasma lipid levels and epididymal WAT sizes in HFD-fed rats). CSEE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and its primary downstream targeting enzyme, acetyl-CoA carboxylase, up-regulated gene expression of carnitine palmitoyl transferase 1, and down-regulated sterol regulatory element-binding protein 1 and fatty acid synthase protein levels in epididymal WAT of HFD-fed rats. CSEE could attenuate lipid accumulation in WAT via AMPK signaling pathway activation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Mesenchymal stem cells promote colorectal cancer progression through AMPK/mTOR-mediated NF-κB activation.

    Science.gov (United States)

    Wu, Xiao-Bing; Liu, Yang; Wang, Gui-Hua; Xu, Xiao; Cai, Yang; Wang, Hong-Yi; Li, Yan-Qi; Meng, Hong-Fang; Dai, Fu; Jin, Ji-De

    2016-02-19

    Mesenchymal stem cells (MSCs) exert a tumor-promoting effect in a variety of human cancers. This study was designed to identify the molecular mechanisms related to the tumor-promoting effect of MSCs in colorectal cancer. In vitro analysis of colorectal cancer cell lines cultured in MSC conditioned media (MSC-CM) showed that MSC-CM significantly promoted the progression of the cancer cells by enhancing cell proliferation, migration and colony formation. The tumorigenic effect of MSC-CM was attributed to altered expression of cell cycle regulatory proteins and inhibition of apoptosis. Furthermore, MSC-CM induced high level expression of a number of pluripotency factors in the cancer cells. ELISAs revealed MSC-CM contained higher levels of IL-6 and IL-8, which are associated with the progression of cancer. Moreover, MSC-CM downregulated AMPK mRNA and protein phosphorylation, but upregulated mTOR mRNA and protein phosphorylation. The NF-κB pathway was activated after addition of MSC-CM. An in vivo model in Balb/C mice confirmed the ability of MSC-CM to promote the invasion and proliferation of colorectal cancer cells. This study indicates that MSCs promote the progression of colorectal cancer via AMPK/mTOR-mediated NF-κB activation.

  2. Resveratrol prevents oxidative stress-induced senescence and proliferative dysfunction by activating the AMPK-FOXO3 cascade in cultured primary human keratinocytes.

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    Yasuo Ido

    Full Text Available The aging process is perceived as resulting from a combination of intrinsic factors such as changes in intracellular signaling and extrinsic factors, most notably environmental stressors. In skin, the relationship between intrinsic changes and keratinocyte function is not clearly understood. Previously, we found that increasing the activity of AMP-activated protein kinase (AMPK suppressed senescence in hydrogen peroxide (H2O2-treated human primary keratinocytes, a model of oxidative stress-induced cellular aging. Using this model in the present study, we observed that resveratrol, an agent that increases the activities of both AMPK and sirtuins, ameliorated two age-associated phenotypes: cellular senescence and proliferative dysfunction. In addition, we found that treatment of keratinocytes with Ex527, a specific inhibitor of sirtuin 1 (SIRT1, attenuated the ability of resveratrol to suppress senescence. In keeping with the latter observation, we noted that compared to non-senescent keratinocytes, senescent cells lacked SIRT1. In addition to these effects on H2O2-induced senescence, resveratrol also prevented the H2O2-induced decrease in proliferation (as indicated by 3H-thymidine incorporation in the presence of insulin. This effect was abrogated by inhibition of AMPK but not SIRT1. Compared to endothelium, we found that human keratinocytes expressed relatively high levels of Forkhead box O3 (FOXO3, a downstream target of both AMPK and SIRT1. Treatment of keratinocytes with resveratrol transactivated FOXO3 and increased the expression of its target genes including catalase. Resveratrol's effects on both senescence and proliferation disappeared when FOXO3 was knocked down. Finally, we performed an exploratory study which showed that skin from humans over 50 years old had lower AMPK activity than skin from individuals under age 20. Collectively, these findings suggest that the effects of resveratrol on keratinocyte senescence and proliferation

  3. Wedelolactone Regulates Lipid Metabolism and Improves Hepatic Steatosis Partly by AMPK Activation and Up-Regulation of Expression of PPARα/LPL and LDLR.

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    Yun Zhao

    Full Text Available Hyperlipidemia is considered one of the greatest risk factors of cardiovascular diseases. We investigated the anti-hyperlipidemic effect and the underlying mechanism of wedelolactone, a plant-derived coumestan, in HepG2 cells and high-fat diet (HFD-induced hyperlipidemic hamsters. We showed that in cultured HepG2 cells, wedelolactone up-regulated protein levels of adenosine monophosphate activated protein kinase (AMPK and peroxisome proliferator-activated receptor-alpha (PPARα as well as the gene expression of AMPK, PPARα, lipoprotein lipase (LPL, and the low-density lipoprotein receptor (LDLR. Meanwhile, administration of wedelolactone for 4 weeks decreased the lipid profiles of plasma and liver in HFD-induced hyperlipidemic hamsters, including total cholesterol (TC, triglycerides (TG, and low-density lipoprotein-cholesterol (LDL-C. The activation of AMPK and up-regulation of PPARα was also observed with wedelolactone treatment. Furthermore, wedelolactone also increased the activities of superoxidase dismutase (SOD and glutathione peroxidase (GSH-Px and decreased the level of the lipid peroxidation product malondialdehyde (MDA in the liver, therefore decreasing the activity of alanine aminotransferase (ALT. In conclusion, we provide novel experimental evidence that wedelolactone possesses lipid-lowering and steatosis-improving effects, and the underlying mechanism is, at least in part, mediated by the activation of AMPK and the up-regulation of PPARα/LPL and LDLR.

  4. Anti-Diabetic Activities of Jiaotaiwan in db/db Mice by Augmentation of AMPK Protein Activity and Upregulation of GLUT4 Expression

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    Na Hu

    2013-01-01

    Full Text Available Jiaotaiwan (JTW, which is composed of Coptis chinensis (CC and cinnamon (CIN, is one of the most well-known traditional Chinese medicines. In this study, we investigated the antidiabetic effects and mechanism of JTW in db/db mice. Results showed that JTW significantly decreased the level of fasting blood glucose and improved glucose and insulin tolerance better than CC or CIN alone. JTW also effectively protected the pancreatic islet shape, augmented the activation of AMP-activated protein kinase (AMPK in the liver, and increased the expression of glucose transporter 4 (GLUT4 protein in skeletal muscle and white fat. AMPK and GLUT4 contributed to glucose metabolism regulation and had an essential function in the development of diabetes mellitus (DM. Therefore, the mechanisms of JTW may be related to suppressing gluconeogenesis by activating AMPK in the liver and affecting glucose uptake in surrounding tissues through the upregulation of GLUT4 protein expression. These findings provided a new insight into the antidiabetic clinical applications of JTW and demonstrated the potential of JTW as a new drug candidate for DM treatment.

  5. Fenofibrate Induces Ketone Body Production in Melanoma and Glioblastoma Cells

    Science.gov (United States)

    Grabacka, Maja M.; Wilk, Anna; Antonczyk, Anna; Banks, Paula; Walczyk-Tytko, Emilia; Dean, Matthew; Pierzchalska, Malgorzata; Reiss, Krzysztof

    2016-01-01

    Ketone bodies [beta-hydroxybutyrate (bHB) and acetoacetate] are mainly produced in the liver during prolonged fasting or starvation. bHB is a very efficient energy substrate for sustaining ATP production in peripheral tissues; importantly, its consumption is preferred over glucose. However, the majority of malignant cells, particularly cancer cells of neuroectodermal origin such as glioblastoma, are not able to use ketone bodies as a source of energy. Here, we report a novel observation that fenofibrate, a synthetic peroxisome proliferator-activated receptor alpha (PPARa) agonist, induces bHB production in melanoma and glioblastoma cells, as well as in neurospheres composed of non-transformed cells. Unexpectedly, this effect is not dependent on PPARa activity or its expression level. The fenofibrate-induced ketogenesis is accompanied by growth arrest and downregulation of transketolase, but the NADP/NADPH and GSH/GSSG ratios remain unaffected. Our results reveal a new, intriguing aspect of cancer cell biology and highlight the benefits of fenofibrate as a supplement to both canonical and dietary (ketogenic) therapeutic approaches against glioblastoma. PMID:26869992

  6. Fenofibrate induces ketone body production in melanoma and glioblastoma cells

    Directory of Open Access Journals (Sweden)

    Maja M Grabacka

    2016-02-01

    Full Text Available Ketone bodies (beta-hydroxybutyrate, bHB, acetoacetate are mainly produced in the liver during prolonged fasting or starvation. bHB is a very efficient energy substrate for sustaining ATP production in peripheral tissues; importantly its consumption is preferred over glucose. However, the majority of malignant cells, particularly cancer cells of neuroectodermal origin such as glioblastoma, are not able to use ketone bodies as a source of energy. Here, we report a novel observation that fenofibrate, a synthetic peroxisome proliferator-activated receptor alpha (PPARa agonist, induces bHB production in melanoma and glioblastoma cells, as well as in neurospheres composed of nontransformed cells. Unexpectedly, this effect is not dependent on PPARa activity or its expression level. The fenofibrate-induced ketogenesis is accompanied by growth arrest and down-regulation of transketolase, but the NADP/NADPH and GSH/GSSG ratios remain unaffected. Our results reveal a new, intriguing aspect of cancer cell biology and highlight the benefits of fenofibrate as a supplement to both canonical and dietary (ketogenic therapeutic approaches against glioblastoma.

  7. Uridine prevents fenofibrate-induced fatty liver.

    Directory of Open Access Journals (Sweden)

    Thuc T Le

    Full Text Available Uridine, a pyrimidine nucleoside, can modulate liver lipid metabolism although its specific acting targets have not been identified. Using mice with fenofibrate-induced fatty liver as a model system, the effects of uridine on liver lipid metabolism are examined. At a daily dosage of 400 mg/kg, fenofibrate treatment causes reduction of liver NAD(+/NADH ratio, induces hyper-acetylation of peroxisomal bifunctional enzyme (ECHD and acyl-CoA oxidase 1 (ACOX1, and induces excessive accumulation of long chain fatty acids (LCFA and very long chain fatty acids (VLCFA. Uridine co-administration at a daily dosage of 400 mg/kg raises NAD(+/NADH ratio, inhibits fenofibrate-induced hyper-acetylation of ECHD, ACOX1, and reduces accumulation of LCFA and VLCFA. Our data indicates a therapeutic potential for uridine co-administration to prevent fenofibrate-induced fatty liver.

  8. Treatment with Fenofibrate plus a low dose of Benznidazole attenuates cardiac dysfunction in experimental Chagas disease

    Directory of Open Access Journals (Sweden)

    Ágata C. Cevey

    2017-12-01

    Full Text Available Trypanosoma cruzi induces serious cardiac alterations during the chronic infection. Intense inflammatory response observed from the beginning of infection, is critical for the control of parasite proliferation and evolution of Chagas disease. Peroxisome proliferator-activated receptors (PPAR-α, are known to modulate inflammation.In this study we investigated whether a PPAR-α agonist, Fenofibrate, improves cardiac function and inflammatory parameters in a murine model of T. cruzi infection. BALB/c mice were sequentially infected with two T. cruzi strains of different genetic background. Benznidazole, commonly used as trypanocidal drug, cleared parasites but did not preclude cardiac pathology, resembling what is found in human chronic chagasic cardiomyopathy. Fenofibrate treatment restored to normal values the ejection and shortening fractions, left ventricular end-diastolic, left ventricular end-systolic diameter, and isovolumic relaxation time. Moreover, it reduced cardiac inflammation and fibrosis, decreased the expression of pro-inflammatory (IL-6, TNF-α and NOS2 and heart remodeling mediators (MMP-9 and CTGF, and reduced serum creatine kinase activity. The fact that Fenofibrate partially inhibited NOS2 expression and NO release in the presence of a PPAR-α non-competitive inhibitor, suggested it also acted through PPAR-α-independent pathways. Since IκBα cytosolic degradation was inhibited by Fenofibrate, it can be concluded that the NFκB pathway has a role in its effects. Thus, we demonstrate that Fenofibrate acts through PPAR-α-dependent and -independent pathways.Our study shows that combined treatment with Fenofibrate plus Benznidazole is able both to reverse the cardiac dysfunction associated with the ongoing inflammatory response and fibrosis and to attain parasite clearance in an experimental model of Chagas disease. Keywords: Trypanosoma cruzi, Heart dysfunction, PPAR-α, Fenofibrate treatment, Inflammatory mediators

  9. AMP-Activated Kinase (AMPK Activation by AICAR in Human White Adipocytes Derived from Pericardial White Adipose Tissue Stem Cells Induces a Partial Beige-Like Phenotype.

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    Omar Abdul-Rahman

    Full Text Available Beige adipocytes are special cells situated in the white adipose tissue. Beige adipocytes, lacking thermogenic cues, morphologically look quite similar to regular white adipocytes, but with a markedly different response to adrenalin. White adipocytes respond to adrenergic stimuli by enhancing lipolysis, while in beige adipocytes adrenalin induces mitochondrial biogenesis too. A key step in the differentiation and function of beige adipocytes is the deacetylation of peroxisome proliferator-activated receptor (PPARγ by SIRT1 and the consequent mitochondrial biogenesis. AMP-activated protein kinase (AMPK is an upstream activator of SIRT1, therefore we set out to investigate the role of AMPK in beige adipocyte differentiation using human adipose-derived mesenchymal stem cells (hADMSCs from pericardial adipose tissue. hADMSCs were differentiated to white and beige adipocytes and the differentiation medium of the white adipocytes was supplemented with 100 μM [(2R,3S,4R,5R-5-(4-Carbamoyl-5-aminoimidazol-1-yl-3,4-dihydroxyoxolan-2-yl]methyl dihydrogen phosphate (AICAR, a known activator of AMPK. The activation of AMPK with AICAR led to the appearance of beige-like morphological properties in differentiated white adipocytes. Namely, smaller lipid droplets appeared in AICAR-treated white adipocytes in a similar fashion as in beige cells. Moreover, in AICAR-treated white adipocytes the mitochondrial network was more fused than in white adipocytes; a fused mitochondrial system was characteristic to beige adipocytes. Despite the morphological similarities between AICAR-treated white adipocytes and beige cells, functionally AICAR-treated white adipocytes were similar to white adipocytes. We were unable to detect increases in basal or cAMP-induced oxygen consumption rate (a marker of mitochondrial biogenesis when comparing control and AICAR-treated white adipocytes. Similarly, markers of beige adipocytes such as TBX1, UCP1, CIDEA, PRDM16 and TMEM26 remained

  10. Theoretical and experimental study of fenofibrate and simvastatin

    Science.gov (United States)

    Nicolás Vázquez, Inés; Rodríguez-Núñez, Jesús Rubén; Peña-Caballero, Vicente; Ruvalcaba, Rene Miranda; Aceves-Hernandez, Juan Manuel

    2017-12-01

    Fenofibrate, an oral fibrate lipid lowering agent, and simvastatin, which reduces plasma levels of low-density lipoprotein cholesterol, are active pharmaceutical ingredients (APIs), currently in the market. We characterized these APIs by thermal analysis and conducted X-ray powder diffraction techniques. Studies should be carried out in the formulation stage before the final composition of a polypill may be established. Thus, it was found in thermochemical studies that both compounds present no chemical interactions in an equimolar mixture of solid samples at room temperature. Theoretical studies were employed to determine possible interactions between fenofibrate and simvastatin. A very weak intramolecular hydrogen bond is formed between the hydroxyl group (O5H5) of the simvastatin with chlorine and carbonyl group (C11O4, C1O2) of the fenofibrate molecule. These weak energy hydrogen bonds have no effect on the chemical stability of the compounds studied. The results were obtained using Density Functional Theory methods; particularly the BPE1BPE and B3LYP functional and 6-31++G** basis set. The values of energy show good approximation when are compared with similar calculations previously reported. Infrared spectra of monomers and dimers were obtained via theoretical calculations.

  11. Fenofibrate inhibits atrial metabolic remodelling in atrial fibrillation through PPAR-α/sirtuin 1/PGC-1α pathway.

    Science.gov (United States)

    Liu, Guang-Zhong; Hou, Ting-Ting; Yuan, Yue; Hang, Peng-Zhou; Zhao, Jing-Jing; Sun, Li; Zhao, Guan-Qi; Zhao, Jing; Dong, Jing-Mei; Wang, Xiao-Bing; Shi, Hang; Liu, Yong-Wu; Zhou, Jing-Hua; Dong, Zeng-Xiang; Liu, Yang; Zhan, Cheng-Chuang; Li, Yue; Li, Wei-Min

    2016-03-01

    Atrial metabolic remodelling is critical for the process of atrial fibrillation (AF). The PPAR-α/sirtuin 1 /PPAR co-activator α (PGC-1α) pathway plays an important role in maintaining energy metabolism. However, the effect of the PPAR-α agonist fenofibrate on AF is unclear. Therefore, the aim of this study was to determine the effect of fenofibrate on atrial metabolic remodelling in AF and explore its possible mechanisms of action. The expression of metabolic proteins was examined in the left atria of AF patients. Thirty-two rabbits were divided into sham, AF (pacing with 600 beats·min(-1) for 1 week), fenofibrate treated (pretreated with fenofibrate before pacing) and fenofibrate alone treated (for 2 weeks) groups. HL-1 cells were subjected to rapid pacing in the presence or absence of fenofibrate, the PPAR-α antagonist GW6471 or sirtuin 1-specific inhibitor EX527. Metabolic factors, circulating biochemical metabolites, atrial electrophysiology, adenine nucleotide levels and accumulation of glycogen and lipid droplets were assessed. The PPAR-α/sirtuin 1/PGC-1α pathway was significantly inhibited in AF patients and in the rabbit/HL-1 cell models, resulting in a reduction of key downstream metabolic factors; this effect was significantly restored by fenofibrate. Fenofibrate prevented the alterations in circulating biochemical metabolites, reduced the level of adenine nucleotides and accumulation of glycogen and lipid droplets, reversed the shortened atrial effective refractory period and increased risk of AF. Fenofibrate inhibited atrial metabolic remodelling in AF by regulating the PPAR-α/sirtuin 1/PGC-1α pathway. The present study may provide a novel therapeutic strategy for AF. © 2016 The British Pharmacological Society.

  12. Adiponectin enhances osteogenic differentiation in human adipose-derived stem cells by activating the APPL1-AMPK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tong; Wu, Yu-wei; Lu, Hui; Guo, Yuan [Second Dental Center, Peking University School and Hospital of Stomatology, Beijing (China); National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing (China); Tang, Zhi-hui, E-mail: tang_zhihui@live.cn [Second Dental Center, Peking University School and Hospital of Stomatology, Beijing (China); National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology, Beijing (China)

    2015-05-29

    Human adipose-derived stem cells (hASCs) are multipotent progenitor cells with multi-lineage differentiation potential including osteogenesis and adipogenesis. While significant progress has been made in understanding the transcriptional control of hASC fate, little is known about how hASC differentiation is regulated by the autocrine loop. The most abundant adipocytokine secreted by adipocytes, adiponectin (APN) plays a pivotal role in glucose metabolism and energy homeostasis. Growing evidence suggests a positive association between APN and bone formation yet little is known regarding the direct effects of APN on hASC osteogenesis. Therefore, this study was designed to investigate the varied osteogenic effects and regulatory mechanisms of APN in the osteogenic commitment of hASCs. We found that APN enhanced the expression of osteoblast-related genes in hASCs, such as osteocalcin, alkaline phosphatase, and runt-related transcription factor-2 (Runx2, also known as CBFa1), in a dose- and time-dependent manner. This was further confirmed by the higher expression levels of alkaline phosphatase and increased formation of mineralization nodules, along with the absence of inhibition of cell proliferation. Importantly, APN at 1 μg/ml was the optimal concentration, resulting in maximum deposition of calcium nodules, and was significant superior to bone morphogenetic protein 2. Mechanistically, we found for the first time that APN increased nuclear translocation of the leucine zipper motif (APPL)-1 as well as AMP-activated protein kinase (AMPK) phosphorylation, which were reversed by pretreatment with APPL1 siRNA. Our results indicate that APN promotes the osteogenic differentiation of hASCs by activating APPL1-AMPK signaling, suggesting that manipulation of APN is a novel therapeutic target for controlling hASC fate. - Highlights: • Adiponectin enhances osteogenic differentiation in human adipose-derived stem cells. • The knock-down of APPL1 block the enhancement of

  13. Hydrogen-rich medium protects mouse embryonic fibroblasts from oxidative stress by activating LKB1-AMPK-FoxO1 signal pathway.

    Science.gov (United States)

    Lee, Jihyun; Yang, Goowon; Kim, Young-Joo; Tran, Quynh Hoa; Choe, Wonchae; Kang, Insug; Kim, Sung Soo; Ha, Joohun

    2017-09-23

    Persistent oxidative stress is recognized as a major cause of many pathological conditions as well as ageing. However, most clinical trials of dietary antioxidants have failed to produce successful outcomes in treating oxidative stress-induced diseases. Molecular hydrogen (H 2 ) has recently received considerable attention as a therapeutic agent owing to its novel antioxidant properties, a selective scavenger of hydroxyl and peroxynitrite radicals. Beyond this, numerous reports support that H 2 can modulate the activity of various cellular signal pathways. However, its effect on AMP-activated protein kinase (AMPK) signal pathway, a central regulator of energy hemostasis, has remained almost elusive. Here, we report that hydrogen-rich medium activated LKB1-AMPK signal pathway without ATP depletion, which in turn induced FoxO1-dependent transcription of manganese superoxide dismutase and catalase in mouse embryonic fibroblasts. Moreover, hydrogen-rich media effectively reduced the level of reactive oxygen species in cells treated with hydrogen peroxide and protected these cells from apoptosis in an AMPK-dependent manner. These results suggest that the LKB1-AMPK-FoxO1 signaling pathway is a critical mediator of the antioxidant properties of H 2 , further supporting the idea that H 2 acts as a signaling molecule to serve various physiological functions. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Vanillic acid attenuates obesity via activation of the AMPK pathway and thermogenic factors in vivo and in vitro.

    Science.gov (United States)

    Jung, Yunu; Park, Jinbong; Kim, Hye-Lin; Sim, Jung-Eun; Youn, Dong-Hyun; Kang, JongWook; Lim, Seona; Jeong, Mi-Young; Yang, Woong Mo; Lee, Seok-Geun; Ahn, Kwang Seok; Um, Jae-Young

    2018-03-01

    Energy expenditure is a target gaining recent interest for obesity treatment. The antiobesity effect of vanillic acid (VA), a well-known flavoring agent, was investigated in vivo and in vitro. High-fat diet (HFD)-induced obese mice and genetically obese db/db mice showed significantly decreased body weights after VA administration. Two major adipogenic markers, peroxisome proliferator activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), were reduced while the key factor of energy metabolism, AMPKα, was increased in the white adipose tissue and liver tissue of VA-treated mice. Furthermore, VA inhibited lipid accumulation and reduced hepatotoxic/inflammatory markers in liver tissues of mice and HepG2 hepatocytes. VA treatment also decreased differentiation of 3T3-L1 adipocytes by regulating adipogenic factors including PPARγ and C/EBPα. AMPKα small interfering RNA was used to examine whether AMPK was associated with the actions of VA. In AMPKα-nulled 3T3-L1 cells, the inhibitory action of VA on PPARγ and C/EBPα was attenuated. Furthermore, in brown adipose tissues of mice and primary cultured brown adipocytes, VA increased mitochondria- and thermogenesis-related factors such as uncoupling protein 1 and PPARγ-coactivator 1-α. Taken together, our results suggest that VA has potential as an AMPKα- and thermogenesis-activating antiobesity agent.-Jung, Y., Park, J., Kim, H.-L., Sim, J.-E., Youn, D.-H., Kang, J., Lim, S., Jeong, M.-Y., Yang, W. M., Lee, S.-G., Ahn, K. S., Um, J.-Y. Vanillic acid attenuates obesity via activation of the AMPK pathway and thermogenic factors in vivo and in vitro.

  15. CHIP protects against cardiac pressure overload through regulation of AMPK

    Science.gov (United States)

    Schisler, Jonathan C.; Rubel, Carrie E.; Zhang, Chunlian; Lockyer, Pamela; Cyr, Douglas M.; Patterson, Cam

    2013-01-01

    Protein quality control and metabolic homeostasis are integral to maintaining cardiac function during stress; however, little is known about if or how these systems interact. Here we demonstrate that C terminus of HSC70-interacting protein (CHIP), a regulator of protein quality control, influences the metabolic response to pressure overload by direct regulation of the catalytic α subunit of AMPK. Induction of cardiac pressure overload in Chip–/– mice resulted in robust hypertrophy and decreased cardiac function and energy generation stemming from a failure to activate AMPK. Mechanistically, CHIP promoted LKB1-mediated phosphorylation of AMPK, increased the specific activity of AMPK, and was necessary and sufficient for stress-dependent activation of AMPK. CHIP-dependent effects on AMPK activity were accompanied by conformational changes specific to the α subunit, both in vitro and in vivo, identifying AMPK as the first physiological substrate for CHIP chaperone activity and establishing a link between cardiac proteolytic and metabolic pathways. PMID:23863712

  16. FGF21 does not require adipocyte AMP-activated protein kinase (AMPK) or the phosphorylation of acetyl-CoA carboxylase (ACC) to mediate improvements in whole-body glucose homeostasis

    DEFF Research Database (Denmark)

    Mottillo, Emilio P; Desjardins, Eric M; Fritzen, Andreas Mæchel

    2017-01-01

    1β2AKO) and littermate controls were fed a high fat diet (HFD) and treated with native FGF21 or saline for two weeks. Additionally, HFD-fed mice with knock-in mutations on the AMPK phosphorylation sites of acetyl-CoA carboxylase (ACC)1 and ACC2 (DKI mice) along with wild-type (WT) controls received...... AMPK and were not associated with changes in browning of white (WAT) and brown adipose tissue (BAT). Lastly, we assessed whether FGF21 exerted its effects through the AMPK/ACC axis, which is critical in the therapeutic benefits of the anti-diabetic medication metformin. ACC DKI mice had improved...... the inhibitory action of AMPK on ACC. This is in contrast to the anti-diabetic medication metformin and suggests that the treatment of obesity and diabetes with the combination of FGF21 and AMPK activators merits consideration....

  17. Physical exercise decreases fasting hyperglycemia in diabetic mice through AMPK activation

    OpenAIRE

    Pádua, Mônica F. de; Pádua, Thomas F. de; Pauli, José R.; Souza, Cláudio T. de; Silva, Adelino S. R. da; Ropelle, Eloize C. C.; Cintra, Dennys E.; Carvalheira, José Barreto C.; Ropelle, Eduardo R.

    2009-01-01

    INTRODUÇÃO: A deficiência na captação de glicose em tecidos periféricos e o aumento da gliconeogênese hepática são fenômenos fisiopatológicos observados em pacientes diabéticos do tipo 2. O exercício físico é considerado um importante aliado para a melhora do perfil glicêmico em pacientes diabéticos; entretanto, os mecanismos envolvidos nesse processo não estão completamente elucidados. OBJETIVO: Avaliar o papel da proteína AMPK no controle glicêmico em camundongos diabéticos após o exercício...

  18. Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway.

    Science.gov (United States)

    Leem, Kang-Hyun; Kim, Myung-Gyou; Hahm, Young-Tae; Kim, Hye Kyung

    2016-12-09

    Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na⁺-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C ) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

  19. Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway

    Directory of Open Access Journals (Sweden)

    Kang-Hyun Leem

    2016-12-01

    Full Text Available Opuntia ficus-indica var. saboten (OFS has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na+-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C and p38 MAPK (SB203580 abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4 translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

  20. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: Dependence on glucose concentration and role of AMPK

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    Sinnett-Smith, James; Kisfalvi, Krisztina; Kui, Robert [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States); Rozengurt, Enrique, E-mail: erozengurt@mednet.ucla.edu [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Metformin inhibits cancer cell growth but the mechanism(s) are not understood. Black-Right-Pointing-Pointer We show that the potency of metformin is sharply dependent on glucose in the medium. Black-Right-Pointing-Pointer AMPK activation was enhanced in cancer cells incubated in physiological glucose. Black-Right-Pointing-Pointer Reciprocally, metformin potently inhibited mTORC1, DNA synthesis and proliferation. Black-Right-Pointing-Pointer Metformin, at low concentrations, inhibited DNA synthesis through AMPK. -- Abstract: Metformin, a widely used anti-diabetic drug, is emerging as a potential anticancer agent but the mechanisms involved remain incompletely understood. Here, we demonstrate that the potency of metformin induced AMPK activation, as shown by the phosphorylation of its substrates acetyl-CoA carboxylase (ACC) at Ser{sup 79} and Raptor at Ser{sup 792}, was dramatically enhanced in human pancreatic ductal adenocarcinoma (PDAC) cells PANC-1 and MiaPaCa-2 cultured in medium containing physiological concentrations of glucose (5 mM), as compared with parallel cultures in medium with glucose at 25 mM. In physiological glucose, metformin inhibited mTORC1 activation, DNA synthesis and proliferation of PDAC cells stimulated by crosstalk between G protein-coupled receptors and insulin/IGF signaling systems, at concentrations (0.05-0.1 mM) that were 10-100-fold lower than those used in most previous reports. Using siRNA-mediated knockdown of the {alpha}{sub 1} and {alpha}{sub 2} catalytic subunits of AMPK, we demonstrated that metformin, at low concentrations, inhibited DNA synthesis through an AMPK-dependent mechanism. Our results emphasize the importance of using medium containing physiological concentrations of glucose to elucidate the anticancer mechanism of action of metformin in pancreatic cancer cells and other cancer cell types.

  1. Rationale for an adjunctive therapy with fenofibrate in pharmacoresistant nocturnal frontal lobe epilepsy.

    Science.gov (United States)

    Puligheddu, Monica; Melis, Miriam; Pillolla, Giuliano; Milioli, Giulia; Parrino, Liborio; Terzano, Giovanni Mario; Aroni, Sonia; Sagheddu, Claudia; Marrosu, Francesco; Pistis, Marco; Muntoni, Anna Lisa

    2017-10-01

    Nocturnal frontal lobe epilepsy (NFLE) is an idiopathic partial epilepsy with a family history in about 25% of cases, with autosomal dominant inheritance (autosomal dominant NFLE [ADNFLE]). Traditional antiepileptic drugs are effective in about 55% of patients, whereas the rest remains refractory. One of the key pathogenetic mechanisms is a gain of function of neuronal nicotinic acetylcholine receptors (nAChRs) containing the mutated α4 or β2 subunits. Fenofibrate, a common lipid-regulating drug, is an agonist at peroxisome proliferator-activated receptor alpha (PPARα) that is a ligand-activated transcription factor, which negatively modulates the function of β2-containing nAChR. To test clinical efficacy of adjunctive therapy with fenofibrate in pharmacoresistant ADNFLE\\NFLE patients, we first demonstrated the effectiveness of fenofibrate in a mutated mouse model displaying both disease genotype and phenotype. We first tested the efficacy of fenofibrate in transgenic mice carrying the mutation in the α4-nAChR subunit (Chrna4S252F) homologous to that found in humans. Subsequently, an add-on protocol was implemented in a clinical setting and fenofibrate was administered to pharmacoresistant NFLE patients. Here, we show that a chronic fenofibrate diet markedly reduced the frequency of large inhibitory postsynaptic currents (IPSCs) recorded from cortical pyramidal neurons in Chrna4S252F mice, and prevented nicotine-induced increase of IPSC frequency. Moreover, fenofibrate abolished differences between genotypes in the frequency of sleep-related movements observed under basal conditions. Patients affected by NFLE, nonresponders to traditional therapy, by means of adjunctive therapy with fenofibrate displayed a reduction of seizure frequency. Furthermore, digital video-polysomnographic recordings acquired in NFLE subjects after 6 months of adjunctive fenofibrate substantiated the significant effects on control of motor-behavioral seizures. Our preclinical and

  2. Combretum lanceolatum flowers extract shows antidiabetic activity through activation of AMPK by quercetin

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    Carlos Roberto Porto Dechandt

    2013-04-01

    Full Text Available The present study evaluated the antidiabetic activity of the Combretum lanceolatum Pohl ex Eichler, Combretaceae, flowers extract (ClEtOH in diabetic rats. Streptozotocin-diabetic rats were divided into four groups: diabetic control, diabetic treated with 500 mg/kg of metformin and diabetic treated with 250 or 500 mg/kg of ClEtOH for 21 days. The treatment of diabetic rats with 500 mg/kg of ClEtOH promoted an increase in the weight of liver, white adipose tissues and skeletal muscles, improving body weight gain. Diabetic rats treated with 500 mg/kg of ClEtOH also presented reduction in glycemia, glycosuria and urinary urea levels, and increase in liver glycogen content. HPLC chromatogram showed that quercetin is the major compound in the extract. The phosphorylation levels of adenosine monophosphate-activated protein kinase were increased in liver slices incubated in vitro with 50 µg/mL of ClEtOH, similarly to the incubation with metformin (50 µg/mL or quercetin (10 µg/mL. The antihyperglycemic effect of ClEtOH was similar to that of metformin and appears to be through inhibition of gluconeogenesis, since urinary urea was reduced and skeletal muscle mass was increased. These data indicate that the antidiabetic activity of the Combretum lanceolatum extract could be mediated, at least in part, through activation of adenosine monophosphateactivated protein kinase by quercetin.

  3. Combretum lanceolatum flowers extract shows antidiabetic activity through activation of AMPK by quercetin

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    Carlos Roberto Porto Dechandt

    2012-12-01

    Full Text Available The present study evaluated the antidiabetic activity of the Combretum lanceolatum Pohl ex Eichler, Combretaceae, flowers extract (ClEtOH in diabetic rats. Streptozotocin-diabetic rats were divided into four groups: diabetic control, diabetic treated with 500 mg/kg of metformin and diabetic treated with 250 or 500 mg/kg of ClEtOH for 21 days. The treatment of diabetic rats with 500 mg/kg of ClEtOH promoted an increase in the weight of liver, white adipose tissues and skeletal muscles, improving body weight gain. Diabetic rats treated with 500 mg/kg of ClEtOH also presented reduction in glycemia, glycosuria and urinary urea levels, and increase in liver glycogen content. HPLC chromatogram showed that quercetin is the major compound in the extract. The phosphorylation levels of adenosine monophosphate-activated protein kinase were increased in liver slices incubated in vitro with 50 µg/mL of ClEtOH, similarly to the incubation with metformin (50 µg/mL or quercetin (10 µg/mL. The antihyperglycemic effect of ClEtOH was similar to that of metformin and appears to be through inhibition of gluconeogenesis, since urinary urea was reduced and skeletal muscle mass was increased. These data indicate that the antidiabetic activity of the Combretum lanceolatum extract could be mediated, at least in part, through activation of adenosine monophosphateactivated protein kinase by quercetin.

  4. Salicylate activates AMPK and synergizes with metformin to reduce the survival of prostate and lung cancer cells ex vivo through inhibition of de novo lipogenesis.

    Science.gov (United States)

    O'Brien, Andrew J; Villani, Linda A; Broadfield, Lindsay A; Houde, Vanessa P; Galic, Sandra; Blandino, Giovanni; Kemp, Bruce E; Tsakiridis, Theodoros; Muti, Paola; Steinberg, Gregory R

    2015-07-15

    Aspirin, the pro-drug of salicylate, is associated with reduced incidence of death from cancers of the colon, lung and prostate and is commonly prescribed in combination with metformin in individuals with type 2 diabetes. Salicylate activates the AMP-activated protein kinase (AMPK) by binding at the A-769662 drug binding site on the AMPK β1-subunit, a mechanism that is distinct from metformin which disrupts the adenylate charge of the cell. A hallmark of many cancers is high rates of fatty acid synthesis and AMPK inhibits this pathway through phosphorylation of acetyl-CoA carboxylase (ACC). It is currently unknown whether targeting the AMPK-ACC-lipogenic pathway using salicylate and/or metformin may be effective for inhibiting cancer cell survival. Salicylate suppresses clonogenic survival of prostate and lung cancer cells at therapeutic concentrations achievable following the ingestion of aspirin (Salicylate concentrations of 1 mM increased the phosphorylation of ACC and suppressed de novo lipogenesis and these effects were enhanced with the addition of clinical concentrations of metformin (100 μM) and eliminated in mouse embryonic fibroblasts (MEFs) deficient in AMPK β1. Supplementation of media with fatty acids and/or cholesterol reverses the suppressive effects of salicylate and metformin on cell survival indicating the inhibition of de novo lipogenesis is probably important. Pre-clinical studies evaluating the use of salicylate based drugs alone and in combination with metformin to inhibit de novo lipogenesis and the survival of prostate and lung cancers are warranted. © 2015 Authors; published by Portland Press Limited.

  5. Cordycepin Inhibits Lipopolysaccharide (LPS-Induced Tumor Necrosis Factor (TNF-α Production via Activating AMP-Activated Protein Kinase (AMPK Signaling

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    Jian-Li Zhang

    2014-07-01

    Full Text Available Tumor necrosis factor (TNF-α is elevated during the acute phase of Kawasaki disease (KD, which damages vascular endothelial cells to cause systemic vasculitis. In the current study, we investigated the potential role of cordycepin on TNFα expression in both lipopolysaccharide (LPS-stimulated macrophages and ex vivo cultured peripheral blood mononuclear cells (PBMCs of KD patients. We found that cordycepin significantly suppressed LPS-induced TNFα expression and production in mouse macrophages (RAW 264.7 cells and bone marrow-derived macrophages (BMDMs. Meanwhile, cordycepin alleviated TNFα production in KD patients’ PBMCs. PBMCs from healthy controls had a much lower level of basal TNF-α content than that of KD patients. LPS-induced TNF-α production in healthy controls’ PBMCs was also inhibited by cordycepin. For the mechanism study, we discovered that cordycepin activated AMP-activated protein kinase (AMPK signaling in both KD patients’ PBMCs and LPS-stimulated macrophages, which mediated cordycepin-induced inhibition against TNFα production. AMPK inhibition by its inhibitor (compound C or by siRNA depletion alleviated cordycepin’s effect on TNFα production. Further, we found that cordycepin inhibited reactive oxygen species (ROS production and nuclear factor kappa B (NF-κB activation in LPS-stimulate RAW 264.7 cells or healthy controls’ PBMCs. PBMCs of KD patients showed higher basal level of ROS and NF-κB activation, which was also inhibited by cordycepin co-treatment. In conclusion, our data showed that cordycepin inhibited TNFα production, which was associated with AMPK activation as well as ROS and NF-κB inhibition. The results of this study should have significant translational relevance in managing this devastating disease.

  6. Physical activity in the prevention and treatment of diseases of affluence – the key role of AMP-activated protein kinase (AMPK

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    Ewa Grochowska

    2014-09-01

    Full Text Available In developed countries, we can observe an increasing number of people with obesity, type 2 diabetes, dyslipidemia, hypertension and arteriosclerosis. The main reason for this phenomenon is the abnormal energy balance due to sedentary lifestyles. Cardiovascular diseases are the leading cause of death in many countries around the world, nowadays. In this paper, the impact of physical activity on the effectiveness of treatment and prevention of metabolic diseases and cancer is considered. Exercise is one of the factors activating 5’AMP-activated protein kinase (AMPK. This enzyme is crucial in maintaining the energy balance of the cell and the entire organism, and its activation results in excluding the anabolic and switching on the catabolic processes. It is believed that the activation of AMPK is responsible for most of the positive effects resulting from physical exercise. Although there are pharmacological methods of activation of this enzyme, they seem to be not as effective as physical exercise. Therefore, physical activity should be the most important form of prevention and treatment of metabolic diseases.

  7. Epigallocatechin Gallate Reduces Slow-Twitch Muscle Fiber Formation and Mitochondrial Biosynthesis in C2C12 Cells by Repressing AMPK Activity and PGC-1α Expression.

    Science.gov (United States)

    Wang, Lina; Wang, Zhen; Yang, Kelin; Shu, Gang; Wang, Songbo; Gao, Ping; Zhu, Xiaotong; Xi, Qianyun; Zhang, Yongliang; Jiang, Qingyan

    2016-08-31

    Epigallocatechin gallate (EGCG) is a major active compound in green tea polyphenols. EGCG acts as an antioxidant to prevent the cell damage caused by free radicals and their derivatives. In skeletal muscle, exercise causes the accumulation of intracellular reactive oxygen species (ROS) and promotes the formation of slow-type muscle fiber. To determine whether EGCG, as a ROS scavenger, has any effect on skeletal muscle fiber type, we applied different concentrations (0, 5, 25, and 50 μM) of EGCG in the culture medium of differentiated C2C12 cells for 2 days. The fiber-type composition, mitochondrial biogenesis-related gene expression, antioxidant and glucose metabolism enzyme activity, and ROS levels in C2C12 cells were then detected. According to our results, 5 μM EGCG significantly decreased the cellular activity of SDH, 25 μM EGCG significantly downregulated the MyHC I, PGC-1α, NRF-1, and p-AMPK levels and SDH activity while enhancing the CAT and GSH-Px activity and decreasing the intracellular ROS levels, and 50 μM EGCG significantly downregulated MyHC I, PGC-1α, and NRF-1 expression and HK and SDH activity while increasing LDH activity. Furthermore, 300 μM H2O2 and 0.5 mM AMPK agonist (AICAR) improved the expression of MyHC I, PGC-1α, and p-AMPK, which were all reversed by 25 μM EGCG. In conclusion, the effect of EGCG on C2C12 cells may occur through the reduction of the ROS level, thereby decreasing both AMPK activity and PGC-1α expression and eventually reducing slow-twitch muscle fiber formation and mitochondrial biosynthesis.

  8. Chlorogenic acid stimulates glucose transport in skeletal muscle via AMPK activation: a contributor to the beneficial effects of coffee on diabetes.

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    Khang Wei Ong

    Full Text Available Chlorogenic acid (CGA has been shown to delay intestinal glucose absorption and inhibit gluconeogenesis. Our aim was to investigate the role of CGA in the regulation of glucose transport in skeletal muscle isolated from db/db mice and L6 skeletal muscle cells. Oral glucose tolerance test was performed on db/db mice treated with CGA and soleus muscle was isolated for 2-deoxyglucose transport study. 2DG transport was also examined in L6 myotubes with or without inhibitors such as wortmannin or compound c. AMPK was knocked down with AMPKα1/2 siRNA to study its effect on CGA-stimulated glucose transport. GLUT 4 translocation, phosphorylation of AMPK and Akt, AMPK activity, and association of IRS-1 and PI3K were investigated in the presence of CGA. In db/db mice, a significant decrease in fasting blood sugar was observed 10 minutes after the intraperitoneal administration of 250 mg/kg CGA and the effect persisted for another 30 minutes after the glucose challenge. Besides, CGA stimulated and enhanced both basal and insulin-mediated 2DG transports in soleus muscle. In L6 myotubes, CGA caused a dose- and time-dependent increase in glucose transport. Compound c and AMPKα1/2 siRNA abrogated the CGA-stimulated glucose transport. Consistent with these results, CGA was found to phosphorylate AMPK and ACC, consistent with the result of increased AMPK activities. CGA did not appear to enhance association of IRS-1 with p85. However, we observed activation of Akt by CGA. These parallel activations in turn increased translocation of GLUT 4 to plasma membrane. At 2 mmol/l, CGA did not cause any significant changes in viability or proliferation of L6 myotubes. Our data demonstrated for the first time that CGA stimulates glucose transport in skeletal muscle via the activation of AMPK. It appears that CGA may contribute to the beneficial effects of coffee on Type 2 diabetes mellitus.

  9. Folliculin regulates ampk-dependent autophagy and metabolic stress survival.

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    Elite Possik

    2014-04-01

    Full Text Available Dysregulation of AMPK signaling has been implicated in many human diseases, which emphasizes the importance of characterizing AMPK regulators. The tumor suppressor FLCN, responsible for the Birt-Hogg Dubé renal neoplasia syndrome (BHD, is an AMPK-binding partner but the genetic and functional links between FLCN and AMPK have not been established. Strikingly, the majority of naturally occurring FLCN mutations predisposing to BHD are predicted to produce truncated proteins unable to bind AMPK, pointing to the critical role of this interaction in the tumor suppression mechanism. Here, we demonstrate that FLCN is an evolutionarily conserved negative regulator of AMPK. Using Caenorhabditis elegans and mammalian cells, we show that loss of FLCN results in constitutive activation of AMPK which induces autophagy, inhibits apoptosis, improves cellular bioenergetics, and confers resistance to energy-depleting stresses including oxidative stress, heat, anoxia, and serum deprivation. We further show that AMPK activation conferred by FLCN loss is independent of the cellular energy state suggesting that FLCN controls the AMPK energy sensing ability. Together, our data suggest that FLCN is an evolutionarily conserved regulator of AMPK signaling that may act as a tumor suppressor by negatively regulating AMPK function.

  10. Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying; Li, Jia; Li, Shanshan; Li, Yi; Wang, Xiangxiang; Liu, Baolin [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China); Fu, Qiang, E-mail: fuqiang@cpu.edu.cn [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China); Ma, Shiping, E-mail: spma@cpu.edu.cn [Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, 639, Longmian Road, Nanjing 211198 (China); Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Research, China Pharmaceutical University, 639, Longmian Road, Nanjing 211198 (China)

    2015-07-01

    Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult. - Highlights: • Curcumin attenuates glutamate neurotoxicity in the hippocampus. • Curcumin suppresses ER stress in glutamate-induced hippocampus slices. • Curcumin inhibits TXNIP/NLRP3 inflammasome activation. • Regulation of AMPK by curcumin contributes to suppressing ER stress.

  11. Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK

    International Nuclear Information System (INIS)

    Li, Ying; Li, Jia; Li, Shanshan; Li, Yi; Wang, Xiangxiang; Liu, Baolin; Fu, Qiang; Ma, Shiping

    2015-01-01

    Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult. - Highlights: • Curcumin attenuates glutamate neurotoxicity in the hippocampus. • Curcumin suppresses ER stress in glutamate-induced hippocampus slices. • Curcumin inhibits TXNIP/NLRP3 inflammasome activation. • Regulation of AMPK by curcumin contributes to suppressing ER stress

  12. Effect of fenofibrate on blood pressure reduction

    Directory of Open Access Journals (Sweden)

    A K Lipatenkova

    2013-03-01

    Full Text Available Реферат по материалам статей 1. Gilbert K, Nian H, Yu C, Luther JM, Brown NJ. Fenofibrate lowers blood pressure in salt-sensitive but not salt-resistant hypertension. J Hypertens. 2013 Apr;31(4:820-9. doi: 10.1097/HJH.0b013e32835e8227. 2. Kwang K. K. Does Fenofibrate Lower Blood Pressure? Hypertension. 2013 Mar;61(3:e27. doi: 10.1161/HYPERTENSIONAHA.111.00792.

  13. Metformin Inhibits Advanced Glycation End Products-Induced Inflammatory Response in Murine Macrophages Partly through AMPK Activation and RAGE/NFκB Pathway Suppression

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    Zhong’e Zhou

    2016-01-01

    Full Text Available Advanced glycation end products (AGEs are major inflammatory mediators in diabetes, affecting atherosclerosis progression via macrophages. Metformin slows diabetic atherosclerosis progression through mechanisms that remain to be fully elucidated. The present study of murine bone marrow derived macrophages showed that (1 AGEs enhanced proinflammatory cytokines (interleukin-1β (IL-1β, IL-6, and tumor necrosis factor-α (TNF-α mRNA expression, RAGE expression, and NFκB activation; (2 metformin pretreatment inhibited AGEs effects and AGEs-induced cluster designation 86 (CD86 (M1 marker expression, while promoting CD206 (M2 marker surface expression and anti-inflammatory cytokine (IL-10 mRNA expression; and (3 the AMPK inhibitor, Compound C, attenuated metformin effects. In conclusion, metformin inhibits AGEs-induced inflammatory response in murine macrophages partly through AMPK activation and RAGE/NFκB pathway suppression.

  14. Gain of function AMP-activated protein kinase γ3 mutation (AMPKγ3R200Q) in pig muscle increases glycogen storage regardless of AMPK activation.

    Science.gov (United States)

    Scheffler, Tracy L; Park, Sungkwon; Roach, Peter J; Gerrard, David E

    2016-06-01

    Chronic activation of AMP-activated protein kinase (AMPK) increases glycogen content in skeletal muscle. Previously, we demonstrated that a mutation in the ryanodine receptor (RyR1(R615C)) blunts AMPK phosphorylation in longissimus muscle of pigs with a gain of function mutation in the AMPKγ3 subunit (AMPKγ3(R200Q)); this may decrease the glycogen storage capacity of AMPKγ3(R200Q) + RyR1(R615C) muscle. Therefore, our aim in this study was to utilize our pig model to understand how AMPKγ3(R200Q) and AMPK activation contribute to glycogen storage and metabolism in muscle. We selected and bred pigs in order to generate offspring with naturally occurring AMPKγ3(R200Q), RyR1(R615C), and AMPKγ3(R200Q) + RyR1(R615C) mutations, and also retained wild-type littermates (control). We assessed glycogen content and parameters of glycogen metabolism in longissimus muscle. Regardless of RyR1(R615C), AMPKγ3(R200Q) increased the glycogen content by approximately 70%. Activity of glycogen synthase (GS) without the allosteric activator glucose 6-phosphate (G6P) was decreased in AMPKγ3(R200Q) relative to all other genotypes, whereas both AMPKγ3(R200Q) and AMPKγ3(R200Q) + RyR1(R615C) muscle exhibited increased GS activity with G6P. Increased activity of GS with G6P was not associated with increased abundance of GS or hexokinase 2. However, AMPKγ3(R200Q) enhanced UDP-glucose pyrophosphorylase 2 (UGP2) expression approximately threefold. Although UGP2 is not generally considered a rate-limiting enzyme for glycogen synthesis, our model suggests that UGP2 plays an important role in increasing flux to glycogen synthase. Moreover, we have shown that the capacity for glycogen storage is more closely related to the AMPKγ3(R200Q) mutation than activity. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  15. Polyphenolics from mango (Mangifera indica L.) suppress breast cancer ductal carcinoma in situ proliferation through activation of AMPK pathway and suppression of mTOR in athymic nude mice.

    Science.gov (United States)

    Nemec, Matthew J; Kim, Hyemee; Marciante, Alexandria B; Barnes, Ryan C; Hendrick, Erik D; Bisson, William H; Talcott, Stephen T; Mertens-Talcott, Susanne U

    2017-03-01

    The objective of this study was to assess the underlying mechanisms of mango polyphenol decreased cell proliferation and tumor volume in ductal carcinoma in situ breast cancer. We hypothesized that mango polyphenols suppress signaling along the AKT/mTOR axis while up-regulating AMPK. To test this hypothesis, mango polyphenols (0.8 mg gallic acid equivalents per day) and pyrogallol (0.2 mg/day) were administered for 4 weeks to mice xenografted with MCF10DCIS.com cells subcutaneously (n=10 per group). Tumor volumes were significantly decreased, both mango and pyrogallol groups displayed greater than 50% decreased volume compared to control. There was a significant reduction of phosphorylated protein levels of IR, IRS1, IGF-1R, and mTOR by mango; while pyrogallol significantly reduced the phosphorylation levels of IR, IRS1, IGF-1R, p70S6K, and ERK. The protein levels of Sestrin2, which is involved in AMPK-signaling, were significantly elevated in both groups. Also, mango significantly elevated AMPK phosphorylation and pyrogallol significantly elevated LKB1 protein levels. In an in vitro model, mango and pyrogallol increased reactive oxygen species (ROS) generation and arrested cells in S phase. In silico modeling indicates that pyrogallol has the potential to bind directly to the allosteric binding site of AMPK, inducing activation. When AMPK expression was down-regulated using siRNA in vitro, pyrogallol reversed the reduced expression of AMPK. This indicates that pyrogallol not only activates AMPK, but also increases constitutive protein expression. These results suggest that mango polyphenols and their major microbial metabolite, pyrogallol, inhibit proliferation of breast cancer cells through ROS-dependent up-regulation of AMPK and down-regulation of the AKT/mTOR pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Combined Treatment of MCF-7 Cells with AICAR and Methotrexate, Arrests Cell Cycle and Reverses Warburg Metabolism through AMP-Activated Protein Kinase (AMPK) and FOXO1.

    Science.gov (United States)

    Fodor, Tamás; Szántó, Magdolna; Abdul-Rahman, Omar; Nagy, Lilla; Dér, Ádám; Kiss, Borbála; Bai, Peter

    2016-01-01

    Cancer cells are characterized by metabolic alterations, namely, depressed mitochondrial oxidation, enhanced glycolysis and pentose phosphate shunt flux to support rapid cell growth, which is called the Warburg effect. In our study we assessed the metabolic consequences of a joint treatment of MCF-7 breast cancer cells with AICAR, an inducer of AMP-activated kinase (AMPK) jointly with methotrexate (MTX), a folate-analog antimetabolite that blunts de novo nucleotide synthesis. MCF7 cells, a model of breast cancer cells, were resistant to the individual application of AICAR or MTX, however combined treatment of AICAR and MTX reduced cell proliferation. Prolonged joint application of AICAR and MTX induced AMPK and consequently enhanced mitochondrial oxidation and reduced the rate of glycolysis. These metabolic changes suggest an anti-Warburg rearrangement of metabolism that led to the block of the G1/S and the G2/M transition slowing down cell cycle. The slowdown of cell proliferation was abolished when mitotropic transcription factors, PGC-1α, PGC-1β or FOXO1 were silenced. In human breast cancers higher expression of AMPKα and FOXO1 extended survival. AICAR and MTX exerts similar additive antiproliferative effect on other breast cancer cell lines, such as SKBR and 4T1 cells, too. Our data not only underline the importance of Warburg metabolism in breast cancer cells but nominate the AICAR+MTX combination as a potential cytostatic regime blunting Warburg metabolism. Furthermore, we suggest the targeting of AMPK and FOXO1 to combat breast cancer.

  17. Combined Treatment of MCF-7 Cells with AICAR and Methotrexate, Arrests Cell Cycle and Reverses Warburg Metabolism through AMP-Activated Protein Kinase (AMPK and FOXO1.

    Directory of Open Access Journals (Sweden)

    Tamás Fodor

    Full Text Available Cancer cells are characterized by metabolic alterations, namely, depressed mitochondrial oxidation, enhanced glycolysis and pentose phosphate shunt flux to support rapid cell growth, which is called the Warburg effect. In our study we assessed the metabolic consequences of a joint treatment of MCF-7 breast cancer cells with AICAR, an inducer of AMP-activated kinase (AMPK jointly with methotrexate (MTX, a folate-analog antimetabolite that blunts de novo nucleotide synthesis. MCF7 cells, a model of breast cancer cells, were resistant to the individual application of AICAR or MTX, however combined treatment of AICAR and MTX reduced cell proliferation. Prolonged joint application of AICAR and MTX induced AMPK and consequently enhanced mitochondrial oxidation and reduced the rate of glycolysis. These metabolic changes suggest an anti-Warburg rearrangement of metabolism that led to the block of the G1/S and the G2/M transition slowing down cell cycle. The slowdown of cell proliferation was abolished when mitotropic transcription factors, PGC-1α, PGC-1β or FOXO1 were silenced. In human breast cancers higher expression of AMPKα and FOXO1 extended survival. AICAR and MTX exerts similar additive antiproliferative effect on other breast cancer cell lines, such as SKBR and 4T1 cells, too. Our data not only underline the importance of Warburg metabolism in breast cancer cells but nominate the AICAR+MTX combination as a potential cytostatic regime blunting Warburg metabolism. Furthermore, we suggest the targeting of AMPK and FOXO1 to combat breast cancer.

  18. Histological evaluation of AMPK signalling in primary breast cancer

    International Nuclear Information System (INIS)

    Hadad, Sirwan M; Hardie, David G; Fleming, Stewart; Thompson, Alastair M; Baker, Lee; Quinlan, Philip R; Robertson, Katherine E; Bray, Susan E; Thomson, George; Kellock, David; Jordan, Lee B; Purdie, Colin A

    2009-01-01

    AMP-activated protein kinase (AMPK) acts as a cellular fuel gauge that responds to energy stress by suppressing cell growth and biosynthetic processes, thus ensuring that energy-consuming processes proceed only if there are sufficient metabolic resources. Malfunction of the AMPK pathway may allow cancer cells to undergo uncontrolled proliferation irrespective of their molecular energy levels. The aim of this study was to examine the state of AMPK phosphorylation histologically in primary breast cancer in relation to clinical and pathological parameters. Immunohistochemistry was performed using antibodies to phospho-AMPK (pAMPK), phospho-Acetyl Co-A Carboxylase (pACC) an established target for AMPK, HER2, ERα, and Ki67 on Tissue Micro-Array (TMA) slides of two cohorts of 117 and 237 primary breast cancers. The quick score method was used for scoring and patterns of protein expression were compared with clinical and pathological data, including a minimum 5 years follow up. Reduced signal, compared with the strong expression in normal breast epithelium, using a pAMPK antibody was demonstrated in 101/113 (89.4%) and 217/236 (91.9%) of two cohorts of patients. pACC was significantly associated with pAMPK expression (p = 0.007 & p = 0.014 respectively). For both cohorts, reduced pAMPK signal was significantly associated with higher histological grade (p = 0.010 & p = 0.021 respectively) and axillary node metastasis (p = 0.061 & p = 0.039 respectively). No significant association was found between pAMPK and any of HER2, ERα, or Ki67 expression, disease-free survival or overall survival. This study extends in vitro evidence through immunohistochemistry to confirm that AMPK is dysfunctional in primary breast cancer. Reduced signalling via the AMPK pathway, and the inverse relationship with histological grade and axillary node metastasis, suggests that AMPK re-activation could have therapeutic potential in breast cancer

  19. Baicalin and its metabolites suppresses gluconeogenesis through activation of AMPK or AKT in insulin resistant HepG-2 cells.

    Science.gov (United States)

    Wang, Tao; Jiang, Hongmei; Cao, Shijie; Chen, Qian; Cui, Mingyuan; Wang, Zhijie; Li, Dandan; Zhou, Jing; Wang, Tao; Qiu, Feng; Kang, Ning

    2017-12-01

    Scutellaria baicalensis Georgi (S. baicalensis), as a traditional Chinese herbal medicine, is an important component of several famous Chinese medicinal formulas for treating patients with diabetes mellitus. Baicalin (BG), a main bioactive component of S. baicalensis, has been reported to have antidiabetic effects. However, pharmacokinetic studies have indicated that BG has poor oral bioavailability. Therefore, it is hard to explain the pharmacological effects of BG in vivo. Interestingly, several reports show that BG is extensively metabolized in rats and humans. Therefore, we speculate that the BG metabolites might be responsible for the pharmacological effects. In this study, BG and its three metabolites (M1-M3) were examined their effects on glucose consumption in insulin resistant HepG-2 cells with a commercial glucose assay kit. Real-time PCR and western blot assay were used to confirm genes and proteins of interest, respectively. The results demonstrate that BG and its metabolites (except for M3) enhanced the glucose consumption which might be associated with inhibiting the expression of the key gluconeogenic genes, including glucose-6-phosphatase (G6Pase), phosphoenolypyruvate carboxykinase (PEPCK) and glucose transporter 2 (GLUT2). Further study found that BG and M1 could suppress hepatic gluconeogenesis via activation of the AMPK pathway, while M2 could suppress hepatic gluconeogenesis via activation of the PI3K/AKT signaling pathway. Taken together, our findings suggest that both BG and its metabolites have antihyperglycemic activities, and might be the active forms of oral doses of BG in vivo. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Aminoclay–lipid hybrid composite as a novel drug carrier of fenofibrate for the enhancement of drug release and oral absorption

    Directory of Open Access Journals (Sweden)

    Yang L

    2016-03-01

    Full Text Available Liang Yang, Yating Shao, Hyo-Kyung Han BK Plus Project Team, College of Pharmacy, Dongguk University, Goyang, South Korea Abstract: This study aimed to prepare the aminoclay–lipid hybrid composite to enhance the drug release and improve the oral bioavailability of poorly water-soluble fenofibrate. Antisolvent precipitation coupled with an immediate freeze-drying method was adopted to incorporate fenofibrate into aminoclay–lipid hybrid composite (ALC. The optimal composition of the ALC formulation was determined as the ratios of aminoclay to krill oil of 3:1 (w/w, krill oil to fenofibrate of 2:1 (w/w, and antisolvent to solvent of 6:4 (v/v. The morphological characteristics of ALC formulation were determined using scanning electron microscopy, differential scanning calorimetry, and X-ray powder diffraction, which indicated microcrystalline state of fenofibrate in ALC formulation. The ALC formulation achieved almost complete dissolution within 30 minutes, whereas the untreated powder and physical mixture exhibited less than 15% drug release. Furthermore, ALC formulation effectively increased the peak plasma concentration (Cmax and area under the curve (AUC of fenofibric acid (an active metabolite in rats by approximately 13- and seven-fold, respectively. Furthermore, ALC formulation exhibited much lower moisture sorption behavior than the lyophilized formulation using sucrose as a cryoprotectant. Taken together, the present findings suggest that ALC formulation is promising for improving the oral absorption of poorly soluble fenofibrate. Keywords: aminoclay, omega-3 phospholipids, fenofibrate, drug release, oral absorption 

  1. Molecular effect of fenofibrate on PBMC gene transcription related to lipid metabolism in patients with metabolic syndrome.

    Science.gov (United States)

    Moreno-Indias, I; Tinahones, F J; Clemente-Postigo, M; Castellano-Castillo, D; Fernández-García, J C; Macias-Gonzalez, M; Queipo-Ortuño, M I; Cardona, F

    2017-06-01

    Both fasting and postprandial hypertriglyceridaemia are considered independent risk factors for atherosclerosis. Treatment of hypertriglyceridaemia is based on fibrates, which activate the peroxisome proliferator-activated receptor alpha (PPARα). However, the metabolic pathways that activate or inhibit fibrates, and how the postprandial triglyceride levels are modified, have not yet been fully described. Accordingly, the aim of this study was to determine the feasibility of peripheral blood mononuclear cells (PBMC) to study the effects of fenofibrate in patients with the metabolic syndrome. A fat overload was given to 50 patients before and after treatment with fenofibrate for 3 months. Anthropometric and biochemical variables as well as gene expression in PBMC were analysed. After treatment with fenofibrate, we observed a decrease in both baseline and postprandial (3 h after the fat overload) levels of serum triglycerides, cholesterol and uric acid and an increase in HDL cholesterol and apolipoprotein AI levels. After treatment, there was also a rise in PPARα and RXRα expression and changes in genes regulated by PPARα, both baseline and postprandial. Furthermore, in vitro experiments showed that a PPARα agonist changed the expression of genes related with lipid metabolism. Treatment with fenofibrate reduced fasting and postprandial serum triglyceride levels, possibly through a mechanism related with an increase in the expression of RXRα and PPARα, by activating the pathways involved in the uptake and degradation of triglycerides and increasing the synthesis of apolipoprotein. These results suggest that PBMC may be useful for the easy study of fenofibrate actions. © 2017 John Wiley & Sons Ltd.

  2. AMPK regulation of the growth of cultured human keratinocytes

    International Nuclear Information System (INIS)

    Saha, Asish K.; Persons, Kelly; Safer, Joshua D.; Luo Zhijun; Holick, Michael F.; Ruderman, Neil B.

    2006-01-01

    AMP kinase (AMPK) is a fuel sensing enzyme that responds to cellular energy depletion by increasing processes that generate ATP and inhibiting others that require ATP but are not acutely necessary for survival. In the present study, we examined the relationship between AMPK activation and the growth (proliferation) of cultured human keratinocytes and assessed whether the inhibition of keratinocyte growth by vitamin D involves AMPK activation. In addition, we explored whether the inhibition of keratinocyte proliferation as they approach confluence could be AMPK-related. Keratinocytes were incubated for 12 h with the AMPK activator, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR). At concentrations of 10 -4 and 10 -3 M, AICAR inhibited keratinocyte growth by 50% and 95%, respectively, based on measurements of thymidine incorporation into DNA. It also increased AMPK and acetyl CoA carboxylase phosphorylation (P-AMPK and P-ACC) and decreased the concentration of malonyl CoA confirming that AMPK activation had occurred. Incubation with the thiazolidinedione, troglitazone (10 -6 M) caused similar alterations in P-AMPK, P-ACC, and cell growth. In contrast, the well known inhibition of keratinocyte growth by 1,25-dihydroxyvitamin D 3 (10 -7 and 10 -6 M) was not associated with changes in P-AMPK or P-ACC. Like most cells, the growth of keratinocytes diminished as they approached confluence. Thus, it was of note that we found a progressive increase in P-AMPK (1.5- to 2-fold, p 3 is AMPK-independent

  3. The Role of AMPK in Neuromuscular Biology and Disease.

    Science.gov (United States)

    Dial, Athan G; Ng, Sean Y; Manta, Alexander; Ljubicic, Vladimir

    2018-03-20

    AMP-activated protein kinase (AMPK) is a primary regulator of cellular metabolism. Recent studies have revealed that AMPK also mediates the maintenance and plasticity of α-motoneurons, the neuromuscular junction, and skeletal muscle. Furthermore, AMPK stimulation by either genetic, pharmacological, or physiological approaches elicits beneficial phenotypic remodeling in neuromuscular disorders (NMDs). Here, we review the role of AMPK as a governor of neuromuscular biology, and present evidence for AMPK as an effective molecular target for therapeutic pursuit in the context of the most prevalent NMDs, including Duchenne muscular dystrophy, spinal muscular atrophy, and myotonic dystrophy type 1. This information may be useful for engineering AMPK-targeted pharmacological- or lifestyle-based strategies to treat disorders of the neuromuscular system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. CHIP−/−-Mouse Liver: Adiponectin-AMPK-FOXO-Activation Overrides CYP2E1-Elicited JNK1-Activation, Delaying Onset of NASH: Therapeutic Implications

    Science.gov (United States)

    Kim, Sung-Mi; Grenert, James P.; Patterson, Cam; Correia, Maria Almira

    2016-01-01

    Genetic ablation of C-terminus of Hsc70-interacting protein (CHIP) E3 ubiquitin-ligase impairs hepatic cytochrome P450 CYP2E1 degradation. Consequent CYP2E1 gain of function accelerates reactive O2 species (ROS) production, triggering oxidative/proteotoxic stress associated with sustained activation of c-Jun NH2-terminal kinase (JNK)-signaling cascades, pro-inflammatory effectors/cytokines, insulin resistance, progressive hepatocellular ballooning and microvesicular steatosis. Despite this, little evidence of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) was found in CHIP−/−-mice over the first 8–9-months of life. We herein document that this lack of tissue injury is largely due to the concurrent up-regulation and/or activation of the adiponectin-5′-AMP-activated protein kinase (AMPK)-forkhead box O (FOXO)-signaling axis stemming from at the least three synergistic features: Up-regulated expression of adipose tissue adiponectin and its hepatic adipoR1/adipoR2 receptors, stabilization of hepatic AMPKα1-isoform, identified herein for the first time as a CHIP-ubiquitination substrate (unlike its AMPKα2-isoform), as well as nuclear stabilization of FOXOs, well-known CHIP-ubiquitination targets. Such beneficial predominance of the adiponectin-AMPK-FOXO-signaling axis over the sustained JNK-elevation and injurious insulin resistance in CHIP−/−-livers apparently counteracts/delays rapid progression of the hepatic microvesicular steatosis to the characteristic macrovesicular steatosis observed in clinical NASH and/or rodent NASH-models. PMID:27406999

  5. Over-expressions of AMPK subunits in ovarian carcinomas with significant clinical implications

    International Nuclear Information System (INIS)

    Li, Cuilan; Liu, Vincent WS; Chiu, Pui M; Chan, David W; Ngan, Hextan YS

    2012-01-01

    AMP-activated protein kinase (AMPK) has recently been considered as a potential target for cancer therapy. However, the expression status of various subunits of the heterotrimeric AMPK in human cancers is rarely reported. We decided to determine their expressions in ovarian carcinomas and their relationships with the disease. Expressions and locations of the AMPK-α1, -α2, -β1, -β2, -γ1 and -γ2 were detected by quantitative PCR (Q-PCR) and immunohistochemical staining (IHC). Their expression levels in ovarian tumors were compared with normal controls and also correlated with clinicopathological parameters. Except AMPK-α1, expressions of the other five AMPK subunits are significantly higher in ovarian carcinomas as determined by Q-PCR. Although IHC detection of AMPK-γ1 and -γ2 were not successful, over-expressions of AMPK-α2, -β1, and -β2 were further confirmed by IHC. Over-expressions of various AMPK subunits occurred independently and were mainly detected in the cytoplasm. Interestingly, AMPK-α2 and -β1 were also detected in the nucleus and cell membrane, respectively. Clinical correlation analyses indicate that expressions of different AMPK subunits are associated with different subtypes of carcinoma. High expression of AMPK-α2 is significantly associated with endometrioid carcinomas. On the other hand, high expressions of AMPK-β and -γ subunits are associated with mucinous and serous carcinomas, respectively. Furthermore, high expressions of AMPK-β1 and -γ2 are also associated with early and late stages of disease, respectively. Finally, patients with high expression of AMPK-α2 had better prognosis. Aberrant expressions of AMPK subunits may play important roles in ovarian carcinogenesis. Each AMPK subunit may have its own function other than just a component of the AMPK molecule. Correlations with clinical parameters suggest that expressions of AMPK subunits have different clinical implications in ovarian cancer development

  6. Oocyte activation and latent HIV-1 reactivation: AMPK as a common mechanism of action linking the beginnings of life and the potential eradication of HIV-1.

    Science.gov (United States)

    Finley, Jahahreeh

    2016-08-01

    In all mammalian species studied to date, the initiation of oocyte activation is orchestrated through alterations in intracellular calcium (Ca(2+)) signaling. Upon sperm binding to the oocyte plasma membrane, a sperm-associated phospholipase C (PLC) isoform, PLC zeta (PLCζ), is released into the oocyte cytoplasm. PLCζ hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to produce diacylglycerol (DAG), which activates protein kinase C (PKC), and inositol 1,4,5-trisphosphate (IP3), which induces the release of Ca(2+) from endoplasmic reticulum (ER) Ca(2+) stores. Subsequent Ca(2+) oscillations are generated that drive oocyte activation to completion. Ca(2+) ionophores such as ionomycin have been successfully used to induce artificial human oocyte activation, facilitating fertilization during intra-cytoplasmic sperm injection (ICSI) procedures. Early studies have also demonstrated that the PKC activator phorbol 12-myristate 13-acetate (PMA) acts synergistically with Ca(2+) ionophores to induce parthenogenetic activation of mouse oocytes. Interestingly, the Ca(2+)-induced signaling cascade characterizing sperm or chemically-induced oocyte activation, i.e. the "shock and live" approach, bears a striking resemblance to the reactivation of latently infected HIV-1 viral reservoirs via the so called "shock and kill" approach, a method currently being pursued to eradicate HIV-1 from infected individuals. PMA and ionomycin combined, used as positive controls in HIV-1 latency reversal studies, have been shown to be extremely efficient in reactivating latent HIV-1 in CD4(+) memory T cells by inducing T cell activation. Similar to oocyte activation, T cell activation by PMA and ionomycin induces an increase in intracellular Ca(2+) concentrations and activation of DAG, PKC, and downstream Ca(2+)-dependent signaling pathways necessary for proviral transcription. Interestingly, AMPK, a master regulator of cell metabolism that is activated thorough the induction of cellular

  7. Fenofibrate reduces food intake via cholecystokinin

    Directory of Open Access Journals (Sweden)

    S Yu Vorotnikova

    2012-12-01

    Full Text Available Реферат по статье: Park MK, Han Y, Kim MS, Seo E, Kang S, Park SY, Koh H, Kim DK, Lee HJ. Reduction of Food Intake by Fenofibrate is Associated with Cholecystokinin Release in Long-Evans Tokushima Rats. Korean J Physiol Pharmacol. 2012 Jun;16(3:181-6.

  8. Piper retrofractum Vahl. Extract, as a PPARδ and AMPK Activator, Suppresses UVB-Induced Photoaging through Mitochondrial Biogenesis and MMPs Inhibition in Human Dermal Fibroblasts and Hairless Mice

    Directory of Open Access Journals (Sweden)

    Jungon Yun

    2018-01-01

    Full Text Available Photoaging occurs by UVB-irradiation and involves production of reactive oxygen species (ROS and overexpression of matrix metalloproteinases (MMPs, leading to extracellular matrix damage. Piper retrofractum Vahl. is used as a traditional medicine for antiflatulence, expectorant, sedative, and anti-irritant; however, its antiphotoaging effect has not yet been studied. The current study investigated the antiphotoaging effect of standardized Piper retrofractum extract (PRE on UVB-damaged human dermal fibroblasts and hairless mouse skin. PRE treatment activated the peroxisome proliferator-activated receptor delta (PPARδ and the adenosine monophosphate-activated protein kinase (AMPK, consequently upregulating mitochondrial synthesis and reducing ROS production. Additionally, PRE inhibited MMPs expression via suppressing mitogen-activated protein kinase (MAPK and activator protein-1 (AP-1. PRE downregulated UVB-induced inflammatory reactions by inhibiting the nuclear factor-kappa B (NF-κB activity. PRE also enhanced transforming growth factor-beta (TGF-β and the Smad signaling pathway, thereby promoting procollagen gene transcription. Furthermore, oral administration of PRE (300 mg/kg/day similarly regulated the signaling pathways and increased antioxidant enzyme expression, thus attenuating physiological deformations, such as wrinkle formation and erythema response. Collectively, these results suggest that PRE acts as a potent antiphotoaging agent via PPARδ and AMPK activation.

  9. Activation of Transient Receptor Potential Vanilloid 4 Impairs the Dendritic Arborization of Newborn Neurons in the Hippocampal Dentate Gyrus through the AMPK and Akt Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Yujing Tian

    2017-06-01

    Full Text Available Neurite growth is an important process for the adult hippocampal neurogenesis which is regulated by a specific range of the intracellular free Ca2+ concentration ([Ca2+]i. Transient receptor potential vanilloid 4 (TRPV4 is a calcium-permeable channel and activation of it causes an increase in [Ca2+]i. We recently reported that TRPV4 activation promotes the proliferation of stem cells in the adult hippocampal dentate gyrus (DG. The present study aimed to examine the effect of TRPV4 activation on the dendrite morphology of newborn neurons in the adult hippocampal DG. Here, we report that intracerebroventricular injection of the TRPV4 agonist GSK1016790A for 5 days (GSK1016790A-injected mice reduced the number of doublecortin immunopositive (DCX+ cells and DCX+ fibers in the hippocampal DG, showing the impaired dendritic arborization of newborn neurons. The phosphorylated AMP-activated protein kinase (p-AMPK protein level increased from 30 min to 2 h, and then decreased from 1 to 5 days after GSK1016790A injection. The phosphorylated protein kinase B (p-Akt protein level decreased from 30 min to 5 days after GSK1016790A injection; this decrease was markedly attenuated by the AMPK antagonist compound C (CC, but not by the AMPK agonist AICAR. Moreover, the phosphorylated mammalian target of rapamycin (mTOR and p70 ribosomal S6 kinase (p70S6k protein levels were decreased by GSK1016790A; these changes were sensitive to 740 Y-P and CC. The phosphorylation of glycogen synthase kinase 3β (GSK3β at Y216 was increased by GSK1016790A, and this change was accompanied by increased phosphorylation of microtubule-associated protein 2 (MAP2 and collapsin response mediator protein-2 (CRMP-2. These changes were markedly blocked by 740 Y-P and CC. Finally, GSK1016790A-induced decrease of DCX+ cells and DCX+ fibers was markedly attenuated by 740 Y-P and CC, but was unaffected by AICAR. We conclude that TRPV4 activation impairs the dendritic arborization of newborn

  10. Activation of Autophagic Flux against Xenoestrogen Bisphenol-A-induced Hippocampal Neurodegeneration via AMP kinase (AMPK)/Mammalian Target of Rapamycin (mTOR) Pathways*

    Science.gov (United States)

    Agarwal, Swati; Tiwari, Shashi Kant; Seth, Brashket; Yadav, Anuradha; Singh, Anshuman; Mudawal, Anubha; Chauhan, Lalit Kumar Singh; Gupta, Shailendra Kumar; Choubey, Vinay; Tripathi, Anurag; Kumar, Amit; Ray, Ratan Singh; Shukla, Shubha; Parmar, Devendra; Chaturvedi, Rajnish Kumar

    2015-01-01

    The human health hazards related to persisting use of bisphenol-A (BPA) are well documented. BPA-induced neurotoxicity occurs with the generation of oxidative stress, neurodegeneration, and cognitive dysfunctions. However, the cellular and molecular mechanism(s) of the effects of BPA on autophagy and association with oxidative stress and apoptosis are still elusive. We observed that BPA exposure during the early postnatal period enhanced the expression and the levels of autophagy genes/proteins. BPA treatment in the presence of bafilomycin A1 increased the levels of LC3-II and SQSTM1 and also potentiated GFP-LC3 puncta index in GFP-LC3-transfected hippocampal neural stem cell-derived neurons. BPA-induced generation of reactive oxygen species and apoptosis were mitigated by a pharmacological activator of autophagy (rapamycin). Pharmacological (wortmannin and bafilomycin A1) and genetic (beclin siRNA) inhibition of autophagy aggravated BPA neurotoxicity. Activation of autophagy against BPA resulted in intracellular energy sensor AMP kinase (AMPK) activation, increased phosphorylation of raptor and acetyl-CoA carboxylase, and decreased phosphorylation of ULK1 (Ser-757), and silencing of AMPK exacerbated BPA neurotoxicity. Conversely, BPA exposure down-regulated the mammalian target of rapamycin (mTOR) pathway by phosphorylation of raptor as a transient cell's compensatory mechanism to preserve cellular energy pool. Moreover, silencing of mTOR enhanced autophagy, which further alleviated BPA-induced reactive oxygen species generation and apoptosis. BPA-mediated neurotoxicity also resulted in mitochondrial loss, bioenergetic deficits, and increased PARKIN mitochondrial translocation, suggesting enhanced mitophagy. These results suggest implication of autophagy against BPA-mediated neurodegeneration through involvement of AMPK and mTOR pathways. Hence, autophagy, which arbitrates cell survival and demise during stress conditions, requires further assessment to be

  11. ADIPOQ/adiponectin induces cytotoxic autophagy in breast cancer cells through STK11/LKB1-mediated activation of the AMPK-ULK1 axis.

    Science.gov (United States)

    Chung, Seung J; Nagaraju, Ganji Purnachandra; Nagalingam, Arumugam; Muniraj, Nethaji; Kuppusamy, Panjamurthy; Walker, Alyssa; Woo, Juhyung; Győrffy, Balázs; Gabrielson, Ed; Saxena, Neeraj K; Sharma, Dipali

    2017-08-03

    ADIPOQ/adiponectin, an adipocytokine secreted by adipocytes in the breast tumor microenvironment, negatively regulates cancer cell growth hence increased levels of ADIPOQ/adiponectin are associated with decreased breast cancer growth. However, its mechanisms of action remain largely elusive. We report that ADIPOQ/adiponectin induces a robust accumulation of autophagosomes, increases MAP1LC3B-II/LC3B-II and decreases SQSTM1/p62 in breast cancer cells. ADIPOQ/adiponectin-treated cells and xenografts exhibit increased expression of autophagy-related proteins. LysoTracker Red-staining and tandem-mCherry-GFP-LC3B assay show that fusion of autophagosomes and lysosomes is augmented upon ADIPOQ/adiponectin treatment. ADIPOQ/adiponectin significantly inhibits breast cancer growth and induces apoptosis both in vitro and in vivo, and these events are preceded by macroautophagy/autophagy, which is integral for ADIPOQ/adiponectin-mediated cell death. Accordingly, blunting autophagosome formation, blocking autophagosome-lysosome fusion or genetic-knockout of BECN1/Beclin1 and ATG7 effectively impedes ADIPOQ/adiponectin induced growth-inhibition and apoptosis-induction. Mechanistic studies show that ADIPOQ/adiponectin reduces intracellular ATP levels and increases PRKAA1 phosphorylation leading to ULK1 activation. AMPK-inhibition abrogates ADIPOQ/adiponectin-induced ULK1-activation, LC3B-turnover and SQSTM1/p62-degradation while AMPK-activation potentiates ADIPOQ/adiponectin's effects. Further, ADIPOQ/adiponectin-mediated AMPK-activation and autophagy-induction are regulated by upstream master-kinase STK11/LKB1, which is a key node in antitumor function of ADIPOQ/adiponectin as STK11/LKB1-knockout abrogates ADIPOQ/adiponectin-mediated inhibition of breast tumorigenesis and molecular analyses of tumors corroborate in vitro mechanistic findings. ADIPOQ/adiponectin increases the efficacy of chemotherapeutic agents. Notably, high expression of ADIPOQ receptor ADIPOR2, ADIPOQ

  12. AMPK-mediated AS160 phosphorylation in skeletal muscle is dependent on AMPK catalytic and regulatory subunits

    DEFF Research Database (Denmark)

    Treebak, Jonas Thue; Glund, Stephan; Deshmukh, Atul

    2006-01-01

    AMP-activated protein kinase (AMPK) is a heterotrimeric protein that regulates glucose transport mediated by cellular stress or pharmacological agonists such as 5-aminoimidazole-4-carboxamide 1 ß-D-ribonucleoside (AICAR). AS160, a Rab GTPase-activating protein, provides a mechanism linking AMPK s...

  13. The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei [Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi' an 710032 (China); Fu, Jianfang [Department of Endocrinology, Xijing Hospital, Fourth Military Medical University, Xi' an 710032 (China); Zhang, Shun [Reproductive Medicine Center, Department of Gynecology and Obstetrics, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Zhao, Jie [Department of Human Anatomy, Histology and Embryology, Fourth Military Medical University, Xi' an 710032 (China); Xie, Nianlin, E-mail: xienianlin@126.com [Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Cai, Guoqing, E-mail: firstchair@fmmu.edu.cn [Department of Gynaecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi' an 710032 (China)

    2015-06-01

    Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli–germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli–germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation. - Highlights: • Intermittent treatment with BTZ caused fertility impairment in adult mice. • BTZ treatment elicited apoptosis during early phase of testicular recovery. • Up-regulation of oxidative stress by BTZ treatment

  14. Euglycemia in Diabetic Rats Leads to Reduced Liver Weight via Increased Autophagy and Apoptosis through Increased AMPK and Caspase-3 and Decreased mTOR Activities

    Directory of Open Access Journals (Sweden)

    Jun-Ho Lee

    2015-01-01

    Full Text Available Euglycemia is the ultimate goal in diabetes care to prevent complications. However, the benefits of euglycemia in type 2 diabetes are controversial because near-euglycemic subjects show higher mortality than moderately hyperglycemic subjects. We previously reported that euglycemic-diabetic rats on calorie-control lose a critical liver weight (LW compared with hyperglycemic rats. Here, we elucidated the molecular mechanisms underlying the loss of LW in euglycemic-diabetic rats and identified a potential risk in achieving euglycemia by calorie-control. Sprague-Dawley diabetic rats generated by subtotal-pancreatectomy were fed a calorie-controlled diet for 7 weeks to achieve euglycemia using 19 kcal% (19R or 6 kcal% (6R protein-containing chow or fed ad libitum (19AL. The diet in both R groups was isocaloric/kg body weight to the sham-operated group (19S. Compared with 19S and hyperglycemic 19AL, both euglycemic R groups showed lower LWs, increased autophagy, and increased AMPK and caspase-3 and decreased mTOR activities. Though degree of insulin deficiency was similar among the diabetic rats, Akt activity was lower, and PTEN activity was higher in both R groups than in 19AL whose signaling patterns were similar to 19S. In conclusion, euglycemia achieved by calorie-control is deleterious in insulin deficiency due to increased autophagy and apoptosis in the liver via AMPK and caspase-3 activation.

  15. Telmisartan ameliorates insulin sensitivity by activating the AMPK/SIRT1 pathway in skeletal muscle of obese db/db mice

    Directory of Open Access Journals (Sweden)

    Shiota Asuka

    2012-11-01

    Full Text Available Abstract Background Telmisartan is a well-established angiotensin II type 1 receptor blocker that improves insulin sensitivity in animal models of obesity and insulin resistance, as well as in humans. Telmisartan has been reported to function as a partial agonist of the peroxisome proliferator-activated receptor (PPAR γ, which is also targeted by the nicotinamide adenine dinucleotide (NAD-dependent deacetylase (SIRT1. Here, we investigated the pathways through which telmisartan acts on skeletal muscle, in vitro as well as in vivo. Methods Nine-week-old male db/db mice were fed a 60% high-fat diet, with orally administrated either vehicle (carboxymethyl-cellulose, CMC, 5 mg/kg telmisartan, or 5 mg/kg telmisartan and 1 mg/kg GW9662, a selective irreversible antagonist of PPARγ, for 5 weeks. Effects of telmisartan on Sirt1 mRNA, AMPK phosphorylation, and NAD+/NADH ratio were determined in C2C12 cultured myocytes. Results and discussion Telmisartan treatment improved insulin sensitivity in obese db/db mice fed a high-fat diet and led to reduction in the size of hypertrophic pancreatic islets in these mice. Moreover, in vitro treatment with telmisartan led to increased expression of Sirt1 mRNA in C2C12 skeletal muscle cells; the increase in Sirt1 mRNA in telmisartan-treated C2C12 myoblasts occurred concomitantly with an increase in AMPK phosphorylation, an increase in NAD+/NADH ratio, and increases in the mRNA levels of PGC1α, FATP1, ACO, and GLUT4. Conclusions Our results indicate that telmisartan acts through a PPARγ-independent pathway, but at least partially exerts its effects by acting directly on skeletal muscle AMPK/SIRT1 pathways.

  16. High-intensity high-volume swimming induces more robust signaling through PGC-1α and AMPK activation than sprint interval swimming in m. triceps brachii.

    Science.gov (United States)

    Casuso, Rafael A; Plaza-Díaz, Julio; Ruiz-Ojeda, Francisco J; Aragón-Vela, Jerónimo; Robles-Sanchez, Cándido; Nordsborg, Nikolai B; Hebberecht, Marina; Salmeron, Luis M; Huertas, Jesus R

    2017-01-01

    We aimed to test whether high-intensity high-volume training (HIHVT) swimming would induce more robust signaling than sprint interval training (SIT) swimming within the m. triceps brachii due to lower metabolic and oxidation. Nine well-trained swimmers performed the two training procedures on separate randomized days. Muscle biopsies from m. triceps brachii and blood samples were collected at three different time points: a) before the intervention (pre), b) immediately after the swimming procedures (post) and c) after 3 h of rest (3 h). Hydroperoxides, creatine kinase (CK), and lactate dehydrogenase (LDH) were quantified from blood samples, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and the AMPKpTHR172/AMPK ratio were quantified by Western blot analysis. PGC-1α, sirtuin 3 (SIRT3), superoxide-dismutase 2 (SOD2), and vascular endothelial growth factor (VEGF) mRNA levels were also quantified. SIT induced a higher release of LDH (p < 0.01 at all time points) and CK (p < 0.01 at post) than HIHVT, but neither SIT nor HIHVT altered systemic hydroperoxides. Additionally, neither SIRT3 nor SOD2 mRNA levels increased, while PGC-1α transcription increased at 3 h after SIT (p < 0.01) and after HIHVT (p < 0.001). However, PGC-1α protein was higher after HIHVT than after SIT (p < 0.05). Moreover, the AMPKpTHR172/AMPK ratio increased at post after SIT (p < 0.05), whereas this effect was delayed after HIHVT as it increased after 3 h (p < 0.05). In addition, VEGF transcription was higher in response to HIHVT (p < 0.05). In conclusion, SIT induces higher muscular stress than HIHVT without increasing systemic oxidation. In addition, HIHVT may induce more robust oxidative adaptations through PGC-1α and AMPK.

  17. The Dipeptidyl Peptidase-4 Inhibitor Teneligliptin Attenuates Hepatic Lipogenesis via AMPK Activation in Non-Alcoholic Fatty Liver Disease Model Mice.

    Science.gov (United States)

    Ideta, Takayasu; Shirakami, Yohei; Miyazaki, Tsuneyuki; Kochi, Takahiro; Sakai, Hiroyasu; Moriwaki, Hisataka; Shimizu, Masahito

    2015-12-08

    Non-alcoholic fatty liver disease (NAFLD), which is strongly associated with metabolic syndrome, is increasingly a major cause of hepatic disorder. Dipeptidyl peptidase (DPP)-4 inhibitors, anti-diabetic agents, are expected to be effective for the treatment of NAFLD. In the present study, we established a novel NAFLD model mouse using monosodium glutamate (MSG) and a high-fat diet (HFD) and investigated the effects of a DPP-4 inhibitor, teneligliptin, on the progression of NAFLD. Male MSG/HFD-treated mice were divided into two groups, one of which received teneligliptin in drinking water. Administration of MSG and HFD caused mice to develop severe fatty changes in the liver, but teneligliptin treatment improved hepatic steatosis and inflammation, as evaluated by the NAFLD activity score. Serum alanine aminotransferase and intrahepatic triglyceride levels were significantly decreased in teneligliptin-treated mice (p Hepatic mRNA levels of the genes involved in de novo lipogenesis were significantly downregulated by teneligliptin (p hepatic expression levels of phosphorylated AMP-activated protein kinase (AMPK) protein. These findings suggest that teneligliptin attenuates lipogenesis in the liver by activating AMPK and downregulating the expression of genes involved in lipogenesis. DPP-4 inhibitors may be effective for the treatment of NAFLD and may be able to prevent its progression to non-alcoholic steatohepatitis.

  18. Activation of autophagy via Ca(2+)-dependent AMPK/mTOR pathway in rat notochordal cells is a cellular adaptation under hyperosmotic stress.

    Science.gov (United States)

    Jiang, Li-Bo; Cao, Lu; Yin, Xiao-Fan; Yasen, Miersalijiang; Yishake, Mumingjiang; Dong, Jian; Li, Xi-Lei

    2015-01-01

    Nucleus pulposus (NP) cells experience hyperosmotic stress in spinal discs; however, how these cells can survive in the hostile microenvironment remains unclear. Autophagy has been suggested to maintain cellular homeostasis under different stresses by degrading the cytoplasmic proteins and organelles. Here, we explored whether autophagy is a cellular adaptation in rat notochordal cells under hyperosmotic stress. Hyperosmotic stress was found to activate autophagy in a dose- and time-dependent manner. SQSTM1/P62 expression was decreased as the autophagy level increased. Transient Ca(2+) influx from intracellular stores and extracellular space was stimulated by hyperosmotic stress. Activation of AMPK and inhibition of p70S6K were observed under hyperosmotic conditions. However, intercellular Ca(2+) chelation inhibited the increase of LC3-II and partly reversed the decrease of p70S6K. Hyperosmotic stress decreased cell viability and promoted apoptosis. Inhibition of autophagy led to SQSTM1/P62 accumulation, reduced cell viability, and accelerated apoptosis in notochordal cells under this condition. These evidences suggest that autophagy induction via the Ca(2+)-dependent AMPK/mTOR pathway might occur as an adaptation mechanism for notochordal cells under hyperosmotic stress. Thus, activating autophagy might be a promising approach to improve viability of notochordal cells in intervertebral discs.

  19. Selective targeting of muscular AMPK by structure based virtual screening

    NARCIS (Netherlands)

    Miglianico, M.; Bleylevens, I.W.M.; Nicolaes, G.A.F.; Neumann, D.

    2012-01-01

    The energy-sensor AMP-activated protein kinase (AMPK) cycles between a glycogen-bound and a free state. The muscle-specific regulatory AMPKβ2 subunit carries a high affinity carbohydrate-binding module (CBM). Upon energy stress, such as exercise, AMPK localization at glycogen allows for rapid

  20. Enhancement of glucose uptake in muscular cell by soybean charged peptides isolated by electrodialysis with ultrafiltration membranes (EDUF): activation of the AMPK pathway.

    Science.gov (United States)

    Roblet, Cyril; Doyen, Alain; Amiot, Jean; Pilon, Geneviève; Marette, André; Bazinet, Laurent

    2014-03-15

    Soy peptides consumption has been associated with beneficial effects in type 2 diabetes patients. However, the peptide fractions responsible for these effects, and their mechanisms of action, have not been identified yet. In this study, we have isolated soybean peptides by electrodialysis with an ultrafiltration membrane (EDUF) at 50 V/100 kDa, and tested them for their capacity to improve glucose uptake in L6 muscle cells. We observed that these fractions were able to significantly enhance glucose uptake in the presence of insulin. The reported bioactivity would be due to the low molecular weight peptides (300-500 Da) recovered. Moreover, we observed that an enhancement of glucose uptake was correlated to the activation of the AMPK enzyme, well known for its capacity to increase glucose uptake in muscle cells. To our knowledge, this is the first time that bioactive peptides with glucose uptake activity have been isolated from a complex soy matrix, and that the implication of AMPK in it is demonstrated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Role of AMPK in skeletal muscle metabolic regulation and adaptation in relation to exercise

    DEFF Research Database (Denmark)

    Jørgensen, Sebastian Beck; Richter, Erik; Wojtaszewski, Jørgen

    2006-01-01

    The 5'-AMP-activated protein kinase (AMPK) is a potent regulator of skeletal muscle metabolism and gene expression. AMPK is activated both in response to in vivo exercise and ex vivo contraction. AMPK is therefore believed to be an important signalling molecule in regulating muscle metabolism...... during exercise as well as in adaptation of skeletal muscle to exercise training. The first part of this review is focused on different mechanisms regulating AMPK activity during muscle work such as alterations in nucleotide concentrations, availability of energy substrates and upstream AMPK kinases. We...... in relation to adaptation of skeletal muscle to exercise training....

  2. Fenofibrate dose not protect glioma cells from irradiation

    International Nuclear Information System (INIS)

    Ro, Jae Lim; Kim, Won Dong; Park, Woo Yoon

    2012-01-01

    Fenofibrate(FF) is a ligand for peroxisome proliferator-activated receptor (PPAR) α and used clinically as a hypolipidemic drug. FF has been reported to have a radioprotective effect of newborn cells in the dentate gyrus 1) and inhibit radiation-induced microglial pro-inflammatory response 2). However, if FF also protect tumor cells, it can not be used clinically during radiotherapy. Thus, we're interested in whether FF has an radioprotective effect of brain tumor cells or not Although the radiosensitive G0/G1 phase cells were increased, radiosensitization by FF was not observed in three human glioma cells. This may be due to counterbalance of radiosensitizing and radioprotecting proteins increased by FF. Taken together, FF neither radiosensitize nor radioprotect glioma cells, so it can be used to protect normal neural cells from radiation damage

  3. [The significance of fenofibrate in the therapy of atherogenic dyslipoproteinaemia].

    Science.gov (United States)

    Kucera, M; Oravec, S; Ocadlík, I

    2010-08-01

    There are accepted the lipid levels goals in all world, which are needed to achievement in primary and secondary prevention. Despite efficacy of current standards of care (including achievement of LDL-C, blood pressure and blood sugar goals), patients with atherogenic dyslipidemia (DLP) (high TG levels, low HDL-C, high apolipoprotein B and small dense LDL-particles), which is common in patients with diabetes melitus (DM), metabolic syndrome or cardiovascular diseases (KVD), remain exposed to a high residual risk of major cardiovascular events and microvascular complications. Statin therapy does not adequately address vascular risk asociated with elevated triglycerides (TG) and low HDL-C levels. As ACCORD lipid trial last time shows, the addition of lipid-modifying activity of fenofibrate to statin therapy benefited only certain subgroups of patients at increased cardiometabolic risk.

  4. AMPK, insulin resistance, and the metabolic syndrome.

    Science.gov (United States)

    Ruderman, Neil B; Carling, David; Prentki, Marc; Cacicedo, José M

    2013-07-01

    Insulin resistance (IR) and hyperinsulinemia are hallmarks of the metabolic syndrome, as are central adiposity, dyslipidemia, and a predisposition to type 2 diabetes, atherosclerotic cardiovascular disease, hypertension, and certain cancers. Regular exercise and calorie restriction have long been known to increase insulin sensitivity and decrease the prevalence of these disorders. The subsequent identification of AMP-activated protein kinase (AMPK) and its activation by exercise and fuel deprivation have led to studies of the effects of AMPK on both IR and metabolic syndrome-related diseases. In this review, we evaluate this body of literature, with special emphasis on the hypothesis that dysregulation of AMPK is both a pathogenic factor for these disorders in humans and a target for their prevention and therapy.

  5. Fenofibrate increases very low density lipoprotein triglyceride production despite reducing plasma triglyceride levels in APOE*3-Leiden.CETP mice

    NARCIS (Netherlands)

    Bijland, S.; Pieterman, E.J.; Maas, A.C.E.; Hoorn, J.W.A. van der; Erk, M.J. van; Klinken, J.B. van; Havekes, L.M.; Dijk, K.W. van; Princen, H.M.G.; Rensen, P.C.N.

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPARα) activator fenofibrate efficiently decreases plasma triglycerides (TG), which is generally attributed to enhanced very low density lipoprotein (VLDL)-TG clearance and decreased VLDL-TG production. However, because data on the effect of

  6. Zanthoxylum ailanthoides Suppresses Oleic Acid-Induced Lipid Accumulation through an Activation of LKB1/AMPK Pathway in HepG2 Cells

    Directory of Open Access Journals (Sweden)

    Eun-Bin Kwon

    2018-01-01

    Full Text Available Zanthoxylum ailanthoides (ZA has been used as folk medicines in East Asian and recently reported to have several bioactivity; however, the studies of ZA on the regulation of triacylglycerol (TG biosynthesis have not been elucidated yet. In this study, we examined whether the methanol extract of ZA (ZA-M could reduce oleic acid- (OA- induced intracellular lipid accumulation and confirmed its mode of action in HepG2 cells. ZA-M was shown to promote the phosphorylation of AMPK and its upstream LKB1, followed by reduction of lipogenic gene expressions. As a result, treatment of ZA-M blocked de novo TG biosynthesis and subsequently mitigated intracellular neutral lipid accumulation in HepG2 cells. ZA-M also inhibited OA-induced production of reactive oxygen species (ROS and TNF-α, suggesting that ZA-M possess the anti-inflammatory feature in fatty acid over accumulated condition. Taken together, these results suggest that ZA-M attenuates OA-induced lipid accumulation and inflammation through the activation of LKB1/AMPK signaling pathway in HepG2 cells.

  7. Green tea polyphenols ameliorate non-alcoholic fatty liver disease through upregulating AMPK activation in high fat fed Zucker fatty rats.

    Science.gov (United States)

    Tan, Yi; Kim, Jane; Cheng, Jing; Ong, Madeleine; Lao, Wei-Guo; Jin, Xing-Liang; Lin, Yi-Guang; Xiao, Linda; Zhu, Xue-Qiong; Qu, Xian-Qin

    2017-06-07

    To investigate protective effects and molecular mechanisms of green tea polyphenols (GTP) on non-alcoholic fatty liver disease (NAFLD) in Zucker fatty (ZF) rats. Male ZF rats were fed a high-fat diet (HFD) for 2 wk then treated with GTP (200 mg/kg) or saline (5 mL/kg) for 8 wk, with Zucker lean rat as their control. At the end of experiment, serum and liver tissue were collected for measurement of metabolic parameters, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), inflammatory cytokines and hepatic triglyceride and liver histology. Immunoblotting was used to detect phosphorylation of AMP-activated protein kinase (AMPK) acetyl-CoA carboxylase (ACC), and sterol regulatory element-binding protein 1c (SREBP1c). Genetically obese ZF rats on a HFD presented with metabolic features of hepatic pathological changes comparable to human with NAFLD. GTP intervention decreased weight gain (10.1%, P = 0.052) and significantly lowered visceral fat (31.0%, P liver in GTP treated rats. The protective effects of GTP against HFD-induced NAFLD in genetically obese ZF rats are positively correlated to reduction in hepatic lipogenesis through upregulating the AMPK pathway.

  8. Fish Oil and Fenofibrate for the Treatment of Hypertriglyceridemia in HIV-Infected Subjects on Antiretroviral Therapy

    Science.gov (United States)

    Gerber, John G.; Kitch, Douglas W.; Fichtenbaum, Carl J.; Zackin, Robert A.; Charles, Stéphannie; Hogg, Evelyn; Acosta, Edward P.; Connick, Elizabeth; Wohl, David; Kojic, E. Milu; Benson, Constance A.; Aberg, Judith A.

    2009-01-01

    Introduction Fish oil has been shown to reduce serum triglyceride (TG) concentrations. In HIV-infected patients on antiretroviral therapy, high TG concentrations likely contribute to increased risk of cardiovascular disease. AIDS Clinical Trials Group A5186 examined the safety and efficacy of fish oil plus fenofibrate in subjects not achieving serum TG levels ≤200 mg/dL with either agent alone. Methods One hundred subjects on highly active antiretroviral therapy with serum TG concentrations ≥400 mg/dL and low-density lipoprotein cholesterol ≤160 mg/dL were randomized to 3 g of fish oil twice daily or 160 mg of fenofibrate daily for 8 weeks. Subjects with a fasting TG level >200 mg/dL at week 8 received a combination of fish oil and fenofibrate in the same doses from week 10 to week 18. Results Median baseline TG was 662 mg/dL in the fish oil group and 694 mg/dL in the fenofibrate group (P = not significant). Fish oil reduced TG levels by a median of 283 mg/dL (46%), fenofibrate reduced them by 367 mg/dL (58%), and combination therapy reduced them by 65.5%. Combination therapy achieved TG levels of ≤200 mg/dL in 22.7% subjects. Fish oil had no measurable effect on immunologic parameters or the pharmacokinetics of lopinavir. Conclusions Fish oil was safe when administered alone or combined with fenofibrate and significantly reduced TG levels in HIV-infected subjects with hypertriglyceridemia. PMID:17971707

  9. Genetic and metabolic effects on skeletal muscle AMPK in young and older twins

    DEFF Research Database (Denmark)

    Mortensen, Brynjulf; Poulsen, Pernille; Wegner, Lise

    2009-01-01

    The protein complex AMP-activated protein kinase (AMPK) is believed to play an important role in the regulation of skeletal muscle glucose and lipid metabolism. Defects in the AMPK system might therefore be an important factor in the pathogenesis of type 2 diabetes. We aimed to identify genetic...... and environmental mechanisms involved in the regulation of AMPK expression and activity and to examine the association between AMPK protein levels and activity on one hand, and glucose and fat metabolism on the other hand. We investigated skeletal muscle biopsies from 100 young and 82 older mono- and dizygotic non...... indicated that skeletal muscle AMPK mRNA and protein expression as well as activity were regulated by sex, age, obesity, and aerobic capacity. Comparison of intraclass correlations on AMPK measures from mono- and dizygotic twins suggested that skeletal muscle AMPK expression was under minor genetic...

  10. Effect of magnesium carbonate on the solubility, dissolution and oral bioavailability of fenofibric acid powder as an alkalising solubilizer.

    Science.gov (United States)

    Kim, Kyeong Soo; Kim, Jeong Hyun; Jin, Sung Giu; Kim, Dong Wuk; Kim, Dong Shik; Kim, Jong Oh; Yong, Chul Soon; Cho, Kwan Hyung; Li, Dong Xun; Woo, Jong Soo; Choi, Han-Gon

    2016-04-01

    To investigate the possibility of developing a novel oral pharmaceutical product using fenofibric acid instead of choline fenofibrate, the powder properties, solubility, dissolution and pharmacokinetics in rats of fenofibrate, choline fenofibrate and fenofibric acid were compared. Furthermore, the effect of magnesium carbonate, an alkalising agent on the solubility, dissolution and oral bioavailability of fenofibric acid was assessed, a mixture of fenofibric acid and magnesium carbonate being prepared by simple blending at a weight ratio of 2/1. The three fenofibrate derivatives showed different particle sizes and melting points with similar crystalline shape. Fenofibric acid had a significantly higher aqueous solubility and dissolution than fenofibrate, but significantly lower solubility and dissolution than choline fenofibrate. However, the fenofibric acid/magnesium carbonate mixture greatly improved the solubility and dissolution of fenofibric acid with an enhancement to levels similar with those for choline fenofibrate. Fenofibric acid gave lower plasma concentrations, AUC and Cmax values compared to choline fenofibrate in rats. However, the mixture resulted in plasma concentrations, AUC and Cmax values levels not significantly different from those for choline fenofibrate. Specifically, magnesium carbonate increased the aqueous solubility, dissolution and bioavailability of fenofibric acid by about 7.5-, 4- and 1.6-fold, respectively. Thus, the mixture of fenofibric acid and magnesium carbonate at the weight ratio of 2/1 might be a candidate for an oral pharmaceutical product with improved oral bioavailability.

  11. Hugan Qingzhi medication ameliorates hepatic steatosis by activating AMPK and PPARα pathways in L02 cells and HepG2 cells.

    Science.gov (United States)

    Yin, JinJin; Luo, YanQin; Deng, HouLiang; Qin, ShuMin; Tang, WaiJiao; Zeng, Lu; Zhou, BenJie

    2014-05-28

    Hugan Qingzhi tablet (HQT), a lipid- lowering traditional Chinese medicine formula, has been used for the prevention and treatment of nonalcoholic fatty liver (NAFLD). This study was realized to evaluate the effects of HQT-medicated serum on hepatic steatosis using in vitro experiments with cells and explore the relevant mechanisms with method of serum pharmacology. A model of hepatic steatosis in the L02 and HepG2 cells was induced by free fatty acid (FFA). The components in the HQT-medicated serum were assayed by high-performance liquid chromatography. Intracellular lipid droplets were detected by Oil Red O staining, and their ultrastructure was examined by transmission electron microscope. The biochemical parameters, including triglyceride (TG), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), total antioxidant capacity (T-AOC), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH), were measured with commercial kits. Furthermore, the expression of adiponectin, AMP-activated protein kinase (AMPK) phosphorylation, sterol regulatory element-binding protein 1 (SREBP-1), peroxisome proliferator activated receptor-α (PPARα), carnitine palmitoyltransferase 1 (CPT-1), and acetyl-CoA oxidase 1 (ACOX1) was analyzed by Western blot and/or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Moderate- and high-dose HQT-medicated serum reduced (Pcontent in L02 and HepG2 cells. They caused significant reductions (P<0.01) in LDH, AST, ALT and MDA and significant increase (P<0.05 or P<0.01) in T-AOC in the culture medium. They also caused increase (P<0.05 or P<0.01) in GSH level and SOD activity in FFA-induced steatotic L02 and HepG2 cells. Furthermore, moderate- and high-dose HQT-medicated serum enhanced (P<0.01) adiponectin expression in a concentration-dependent manner and increased (P<0.05 or P<0.01) the phosphorylation of AMPK and the expression of PPARα, CPT-1, and ACOX1, and reduced

  12. Metformin affects macrophages' phenotype and improves the activity of glutathione peroxidase, superoxide dismutase, catalase and decreases malondialdehyde concentration in a partially AMPK-independent manner in LPS-stimulated human monocytes/macrophages.

    Science.gov (United States)

    Bułdak, Łukasz; Łabuzek, Krzysztof; Bułdak, Rafał Jakub; Kozłowski, Michał; Machnik, Grzegorz; Liber, Sebastian; Suchy, Dariusz; Duława-Bułdak, Anna; Okopień, Bogusław

    2014-06-01

    Diabetic patients experience accelerated atherosclerosis. Metformin is a cornerstone of the current therapy of type 2 diabetes. Macrophages are the key cells associated with the development of atherosclerotic plaques. Therefore, our aim was to assess the in vitro effects of metformin on macrophages and its influence on the mechanisms involved in the development of atherosclerosis. Peripheral blood mononuclear cells were obtained from the group including 16 age-matched healthy non-smoking volunteers aged 18-40 years. Monocytes were further incubated with metformin, LPS and compound C--a pharmacological inhibitor of AMPK. The impact of metformin on oxidative stress markers, antioxidative properties, inflammatory cytokines and phenotypical markers of macrophages was studied. We showed that macrophages treated with metformin expressed less reactive oxygen species (ROS), which resulted from increased antioxidative potential. Furthermore, a reduction in inflammatory cytokines was observed. We also observed a phenotypic shift toward the alternative activation of macrophages that was induced by metformin. All the aforementioned results resulted from AMPK activation, but a residual activity of metformin after AMPK blockade was still noticeable even after inhibition of AMPK by compound C. Authors believe that metformin-based therapy, a cornerstone in diabetes therapy, not only improves the prognosis of diabetics by reducing blood glucose but also by reducing oxidative stress, inflammatory cytokine production and the shift toward alternative activation of macrophages. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  13. The In Vivo Antidiabetic Activity of Nigella sativa Is Mediated through Activation of the AMPK Pathway and Increased Muscle Glut4 Content

    Directory of Open Access Journals (Sweden)

    Ali Benhaddou-Andaloussi

    2011-01-01

    Full Text Available The antidiabetic effect of N. sativa seed ethanol extract (NSE was assessed in Meriones shawi after development of diabetes. Meriones shawi were divided randomly into four groups: normal control, diabetic control, diabetic treated with NSE (2 g eq plant/kg or with metformin (300 mg/kg positive control, both administered by daily intragastric gavage for 4 weeks. Glycaemia and body weight were evaluated weekly. At study's end, an Oral Glucose Tolerance Test (OGTT was performed to estimate insulin sensitivity. Upon sacrifice, plasma lipid profile, insulin, leptin, and adiponectin levels were assessed. ACC phosphorylation and Glut4 protein content were determined in liver and skeletal muscle. NSE animals showed a progressive normalization of glycaemia, albeit slower than that of metformin controls. Moreover, NSE increased insulinemia and HDL-cholesterol, compared to diabetic controls. Leptin and adiponectin were unchanged. NSE treatment decreased OGTT and tended to decrease liver and muscle triglyceride content. NSE stimulated muscle and liver ACC phosphorylation and increased muscle Glut4. These results confirm NSE's previously reported hypoglycaemic and hypolipidemic activity. More significantly, our data demonstrate that in vivo treatment with NSE exerts an insulin-sensitizing action by enhancing ACC phosphorylation, a major component of the insulin-independent AMPK signaling pathway, and by enhancing muscle Glut4 expression.

  14. Altered metabolism and persistent starvation behaviors caused by reduced AMPK function in Drosophila.

    Directory of Open Access Journals (Sweden)

    Erik C Johnson

    2010-09-01

    Full Text Available Organisms must utilize multiple mechanisms to maintain energetic homeostasis in the face of limited nutrient availability. One mechanism involves activation of the heterotrimeric AMP-activated protein kinase (AMPK, a cell-autonomous sensor to energetic changes regulated by ATP to AMP ratios. We examined the phenotypic consequences of reduced AMPK function, both through RNAi knockdown of the gamma subunit (AMPKγ and through expression of a dominant negative alpha (AMPKα variant in Drosophila melanogaster. Reduced AMPK signaling leads to hypersensitivity to starvation conditions as measured by lifespan and locomotor activity. Locomotor levels in flies with reduced AMPK function were lower during unstressed conditions, but starvation-induced hyperactivity, an adaptive response to encourage foraging, was significantly higher than in wild type. Unexpectedly, total dietary intake was greater in animals with reduced AMPK function yet total triglyceride levels were lower. AMPK mutant animals displayed starvation-like lipid accumulation patterns in metabolically key liver-like cells, oenocytes, even under fed conditions, consistent with a persistent starved state. Measurements of O(2 consumption reveal that metabolic rates are greater in animals with reduced AMPK function. Lastly, rapamycin treatment tempers the starvation sensitivity and lethality associated with reduced AMPK function. Collectively, these results are consistent with models that AMPK shifts energy usage away from expenditures into a conservation mode during nutrient-limited conditions at a cellular level. The highly conserved AMPK subunits throughout the Metazoa, suggest such findings may provide significant insight for pharmaceutical strategies to manipulate AMPK function in humans.

  15. Molecular dynamics of amorphous pharmaceutical fenofibrate studied by broadband dielectric spectroscopy

    Directory of Open Access Journals (Sweden)

    U. Sailaja

    2016-06-01

    Full Text Available Fenofibrate is mainly used to reduce cholesterol level in patients at risk of cardiovascular disease. Thermal transition study with the help of differential scanning calorimetry (DSC shows that the aforesaid active pharmaceutical ingredient (API is a good glass former. Based on our DSC study, the molecular dynamics of this API has been carried out by broadband dielectric spectroscopy (BDS covering wide temperature and frequency ranges. Dielectric measurements of amorphous fenofibrate were performed after its vitrification by fast cooling from a few degrees above the melting point (Tm=354.11 K to deep glassy state. The sample does not show any crystallization tendency during cooling and reaches the glassy state. The temperature dependence of the structural relaxation has been fitted by single Vogel–Fulcher–Tamman (VFT equation. From VFT fit, glass transition temperature (Tg was estimated as 250.56 K and fragility (m was determined as 94.02. This drug is classified as a fragile glass former. Deviations of experimental data from Kohlrausch–Williams–Watts (KWW fits on high-frequency flank of α-peak indicate the presence of an excess wing in fenofibrate. Based on Ngai׳s coupling model, we identified the excess wing as true Johari–Goldstein (JG process. Below the glass transition temperature one can clearly see a secondary relaxation (γ with an activation energy of 32.67 kJ/mol.

  16. Effect of fenofibrate on uric acid and gout in type 2 diabetes: a post-hoc analysis of the randomised, controlled FIELD study.

    Science.gov (United States)

    Waldman, Boris; Ansquer, Jean-Claude; Sullivan, David R; Jenkins, Alicia J; McGill, Neil; Buizen, Luke; Davis, Timothy M E; Best, James D; Li, Liping; Feher, Michael D; Foucher, Christelle; Kesaniemi, Y Antero; Flack, Jeffrey; d'Emden, Michael C; Scott, Russell S; Hedley, John; Gebski, Val; Keech, Anthony C

    2018-04-01

    Gout is a painful disorder and is common in type 2 diabetes. Fenofibrate lowers uric acid and reduces gout attacks in small, short-term studies. Whether fenofibrate produces sustained reductions in uric acid and gout attacks is unknown. In the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial, participants aged 50-75 years with type 2 diabetes were randomly assigned to receive either co-micronised fenofibrate 200 mg once per day or matching placebo for a median of 5 years follow-up. We did a post-hoc analysis of recorded on-study gout attacks and plasma uric acid concentrations according to treatment allocation. The outcomes of this analysis were change in uric acid concentrations and risk of on-study gout attacks. The FIELD study is registered with ISRCTN, number ISRCTN64783481. Between Feb 23, 1998, and Nov 3, 2000, 9795 patients were randomly assigned to fenofibrate (n=4895) or placebo (n=4900) in the FIELD study. Uric acid concentrations fell by 20·2% (95% CI 19·9-20·5) during the 6-week active fenofibrate run-in period immediately pre-randomisation (a reduction of 0·06 mmol/L or 1 mg/dL) and remained -20·1% (18·5-21·7, puric acid concentration higher than 0·36 mmol/L and 13·9% in those with baseline uric acid concentration higher than 0·42 mmol/L, compared with 3·4% and 5·7%, respectively, in the fenofibrate group. Risk reductions were similar among men and women and those with dyslipidaemia, on diuretics, and with elevated uric acid concentrations. For participants with elevated baseline uric acid concentrations despite taking allopurinol at study entry, there was no heterogeneity of the treatment effect of fenofibrate on gout risk. Taking account of all gout events, fenofibrate treatment halved the risk (HR 0·48, 95% CI 0·37-0·60; puric acid concentrations by 20%, and almost halved first on-study gout events over 5 years of treatment. Fenofibrate could be a useful adjunct for preventing gout in diabetes. None. Copyright

  17. An Update on AMPK in Hydrogen Sulfide Pharmacology

    Directory of Open Access Journals (Sweden)

    Minjun Wang

    2017-11-01

    Full Text Available Hydrogen sulfide (H2S, the third bio-active gasotransmitter, is produced endogenously and tightly involved in the pathogenesis and treatment for various diseases. Adenosine 5′-monophosphate-activated protein kinase (AMPK plays a paramount role in maintaining cellular energetic balance. Increasing evidences have also suggested AMPK as a novel modulator in multiple pathological conditions. In this paper, we will review the biological principles of H2S and AMPK, and most importantly, the recent discoveries regarding AMPK-mediated pharmacological actions of H2S. Emphasis will be laid on AMPK/H2S interactions in the cardiovascular system, autophagy, diabetic complications, and inflammation. In most cases described in this article, by promoting AMPK activation, H2S exerts cytoprotective effects or therapeutic potentials, though there remain some controversies before we can fully understand the involved mechanisms. Further researches are in need to investigate more closely any relationship between H2S and AMPK, and to put forward the development of H2S donors for clinical application.

  18. The AMPK gamma1 R70Q mutant regulates multiple metabolic and growth pathways in neonatal cardiac myocytes

    Science.gov (United States)

    Although mutations in the gamma-subunit of AMP-activated protein kinase (AMPK) can result in excessive glycogen accumulation and cardiac hypertrophy, the mechanisms by which this occurs have not been well defined. Because >65% of cardiac AMPK activity is associated with the gamma1-subunit of AMPK, w...

  19. Exercício físico reduz a hiperglicemia de jejum em camundongos diabéticos através da ativação da AMPK Physical exercise decreases fasting hyperglycemia in diabetic mice through AMPK activation

    Directory of Open Access Journals (Sweden)

    Mônica F. de Pádua

    2009-06-01

    condition, the insulin tolerance test (ITT and Western blot technique, were combined to assess the glucose homeostasis in diabetic mice (ob/ob and db/db after a single swimming session. RESULTS: Fasting hyperglycemia, severe insulin resistance and deficiency in the AMPK/ACC signaling in muscle and liver observed in the diabetic mice were reversed after the exercise session. The restoration of AMPK/ACC signaling reduced the expression of the gluconeogenic enzyme, PEPCK in the liver, and increased the translocation of GLUT4 in the skeletal muscle. These data indicate that the activation of AMPK/ACC pathway induced by physical exercise is important to reduce fasting glucose levels in experimental models of type 2 diabetes. These data open new insights for determination of physical activity control on the glucose homeostasis in diabetic patients.

  20. How Abbott’s Fenofibrate Franchise Avoided Generic Competition

    Science.gov (United States)

    Downing, Nicholas S.; Ross, Joseph S.; Jackevicius, Cynthia A.; Krumholz, Harlan M.

    2013-01-01

    The ongoing debate concerning the efficacy of fenofibrate has overshadowed an important aspect of the drug’s history: Abbott, the maker of branded fenofibrate, has produced several bioequivalent reformulations, which dominate the market even though generic fenofibrate has been available for almost a decade. This continued use of branded formulations, which cost twice as much as generic versions of fenofibrate, imposes an annual cost of approximately $700 million on our healthcare system. Abbott maintained its dominance of the fenofibrate market, in part, through a complex switching strategy involving the sequential launch of branded reformulations that had not been shown to be superior to the first generation product and patent litigation that delayed the approval of generic formulations. The small differences in dose of the newer branded formulations prevented substitution with generics of older generation products. As soon as direct generic competition seemed likely at the new dose level where substitution would be allowed, Abbott would launch another reformulation and the cycle would repeat. Our objective, using the fenofibrate example, is to describe how current policy can allow pharmaceutical companies to maintain market share using reformulations of branded medications without demonstrating the superiority of next generation products. PMID:22493409

  1. Avoidance of generic competition by Abbott Laboratories' fenofibrate franchise.

    Science.gov (United States)

    Downing, Nicholas S; Ross, Joseph S; Jackevicius, Cynthia A; Krumholz, Harlan M

    2012-05-14

    The ongoing debate concerning the efficacy of fenofibrate has overshadowed an important aspect of the drug's history: Abbott Laboratories, the maker of branded fenofibrate, has produced several bioequivalent reformulations that dominate the market, although generic fenofibrate has been available for almost a decade. This continued use of branded formulations, which cost twice as much as generic versions of fenofibrate, imposes an annual cost of approximately $700 million on the US health care system. Abbott Laboratories maintained its dominance of the fenofibrate market in part through a complex switching strategy involving the sequential launch of branded reformulations that had not been shown to be superior to the first-generation product and patent litigation that delayed the approval of generic formulations. The small differences in dose of the newer branded formulations prevented their substitution with generics of older-generation products. As soon as direct generic competition seemed likely at the new dose level, where substitution would be allowed, Abbott would launch another reformulation, and the cycle would repeat. Based on the fenofibrate example, our objective is to describe how current policy can allow pharmaceutical companies to maintain market share using reformulations of branded medications, without demonstrating the superiority of next-generation products.

  2. AMPK : a master energy regulator for gonadal functions.

    Directory of Open Access Journals (Sweden)

    Michael eBertoldo

    2015-07-01

    Full Text Available From c.elegans to mammals (including humans, nutrition and energy metabolism strongly influence reproduction. At the cellular level, some detectors of energy status indicate whether energy reserves are abundant (obesity, or poor (diet restriction. One of these detectors is AMPK (5 'AMP-activated protein kinase, a protein kinase activated by ATP deficiency but also by several natural substances such as polyphenols or synthetic molecules like metformin, used in the treatment of insulin resistance. AMPK is expressed in muscle and liver, but also in the ovary and testis. This review focuses on the main effects of AMPK identified in gonadal cells. We describe the role of AMPK in gonadal steroidogenesis, in proliferation and survival of somatic gonadal cells and in the maturation of oocytes or spermatozoa. We discuss also the role of AMPK in germ and somatic cell interactions within the cumulus-oocyte complex and in the blood testis barrier. Finally, the interface in the gonad between AMPK and modification of metabolism is reported and discussion about the role of AMPK on fertility, in regards to the treatment of infertility associated with insulin resistance (male obesity, polycystic ovary syndrome.

  3. Blunted response of hippocampal AMPK associated with reduced neurogenesis in older versus younger mice.

    Science.gov (United States)

    Jang, Sooah; Kim, Hyunjeong; Jeong, Jihyeon; Lee, Su Kyoung; Kim, Eun Woo; Park, Minsun; Kim, Chul Hoon; Lee, Jong Eun; Namkoong, Kee; Kim, Eosu

    2016-11-03

    The rate of hippocampal neurogenesis declines with aging. This is partly explained by decreased neural responsiveness to various cues stimulating metabolism. AMP-activated protein kinase (AMPK), a pivotal enzyme regulating energy homeostasis in response to metabolic demands, showed the diminished sensitivity in peripheral tissues during aging. AMPK is also known to be involved in neurogenesis. We aimed to see whether AMPK reactivity is also blunted in the aged hippocampus, and thus is associated with aging-related change in neurogenesis. Following subchronic (7days) intraperitoneal and acute intracerebroventricular (i.c.v.) administration of either 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR; AMPK activator) or saline (sham) to young (16-week-old) and old (72-week-old) mice, we measured changes in AMPK activity, brain-derived neurotrophic factor (BDNF) expression or neurogenesis in the hippocampus. AICAR-induced changes in AMPK activity were observed in the hippocampus of young mice after acute i.c.v. injection. However, neither subchronic nor acute treatment induced significant changes in AMPK activity in old mice. Intriguingly, directions of AICAR-induced changes in AMPK activity were opposite between the hippocampus (decrease) and skeletal muscle (increase). ATP levels were inversely correlated with hippocampal AMPK activity, suggesting that the higher energy levels achieved by AICAR treatment might deactivate neuronal AMPK in young mice. The blunted response of AMPK to AICAR in old age was also indicated by the observations that the levels of neurogenesis and BDNF expression were significantly changed only in young mice upon AICAR treatment. Our findings suggest that the blunted response of neuronal AMPK in old age might be responsible for aging-associated decline in neurogenesis. Therefore, in addition to activation of AMPK, recovering its sensitivity may be necessary to enhance hippocampal neurogenesis in old age. Copyright © 2016 Elsevier Inc. All

  4. Profiling hepatic microRNAs in zebrafish: fluoxetine exposure mimics a fasting response that targets AMP-activated protein kinase (AMPK.

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    Paul M Craig

    Full Text Available This study examined the similarities in microRNA profiles between fasted and fluoxetine (FLX exposed zebrafish and downstream target transcripts and biological pathways. Using a custom designed microarray targeting 270 zebrafish miRNAs, we identified 9 differentially expressed miRNAs targeting transcripts in biological pathways associated with anabolic metabolism, such as adipogenesis, cholesterol biosynthesis, triacylglycerol synthesis, and insulin signaling. Exposure of female zebrafish to 540 ng/L FLX, an environmentally relevant concentration and a known metabolic repressor, increased specific miRNAs indicating greater inhibition of these pathways in spite of continued feeding. Further examination revealed two specific miRNAs, dre-let-7d and dre-miR-140-5p, were predicted in silico to bind to a primary regulator of metabolism, adenosine monophosphate-activated protein kinase (AMPK, and more specifically the two isoforms of the catalytic subunit, AMPKα1 and α2, respectively. Real-time analysis of the relative transcript abundance of the α1 and α2 mRNAs indicated a significant inverse relationship between specific miRNA and target transcript. This suggests that AMPK-related pathways may be compromised during FLX exposure as a result of increased miRNA abundance. The mechanism by which FLX regulates miRNA abundance is unknown but may be direct at the liver. The serotonin transporter, slc6a4, is the target of FLX and other selective serotonin reuptake inhibitors (SSRI and it was found to be expressed in the liver, although treatment did not alter expression of this transporter. Exposure to FLX disrupts key hepatic metabolic pathways, which may be indicative of reduced overall fitness and these effects may be linked to specific miRNA abundance. This has important implications for the heath of fish because concentrations of SSRIs in aquatic ecosystems are continually increasing.

  5. Role of AMPK in Regulating Muscle Insulin Sensitivity

    DEFF Research Database (Denmark)

    Kjøbsted, Rasmus

    obtained during this PhD support a role of AMPK in regulating muscle insulin sensitivity, which may occur through phosphorylation of the downstream target TBC1D4. We find that prior AICAR treatment (pharmacological AMPK activator) and in situ contraction enhance mouse muscle insulin sensitivity in an AMPK...... prevail in healthy lean subjects. In the present thesis, experimental results from the three studies as well as unpublished observations are placed in the context of existing literature in order to provide a general overview of the current understandings within this field of research....

  6. AMPK-independent pathways regulate skeletal muscle fatty acid oxidation

    DEFF Research Database (Denmark)

    Dzamko, Nicolas; Schertzer, Jonathan D.; Ryall, James G.

    2008-01-01

    The activation of AMP-activated protein kinase (AMPK) and phosphorylation/inhibition of acetyl-CoA carboxylase 2 (ACC2) is believed to be the principal pathway regulating fatty acid oxidation. However, during exercise AMPK activity and ACC Ser-221 phosphorylation does not always correlate......-based approach we identified 18 Ser/Thr protein kinases whose phosphorylation was increased by greater than 25% in contracted KD relative to WT muscle. Utilizing bioinformatics we predicted that extracellular regulated protein-serine kinase (ERK1/2), inhibitor of nuclear factor (NF)-kappaB protein-serine kinase...... beta (IKKbeta) and protein kinase D (PKD) may phosphorylate ACC2 at Ser-221 but during in vitro phosphorylation assays only AMPK phosphorylated ACC2. These data demonstrate that AMPK is not essential for the regulation of fatty acid oxidation by AICAR or muscle contraction....

  7. Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation.

    Science.gov (United States)

    MacAskill, Mark G; Watson, David G; Ewart, Marie-Ann; Wadsworth, Roger; Jackson, Andrew; Aitken, Emma; MacKenzie, Graeme; Kingsmore, David; Currie, Susan; Coats, Paul

    2015-08-01

    Creation of an autologous arteriovenous fistula (AVF) for vascular access in haemodialysis is the modality of choice. However neointimal hyperplasia and loss of the luminal compartment result in AVF patency rates of ~60% at 12months. The exact cause of neointimal hyperplasia in the AVF is poorly understood. Vascular trauma has long been associated with hyperplasia. With this in mind in our rabbit model of AVF we simulated cannulation autologous to that undertaken in vascular access procedures and observed significant neointimal hyperplasia as a direct consequence of cannulation. The neointimal hyperplasia was completely inhibited by topical transdermal delivery of the non-steroidal anti-inflammatory (NSAID) diclofenac. In addition to the well documented anti-inflammatory properties we have identified novel anti-proliferative mechanisms demonstrating diclofenac increases AMPK-dependent signalling and reduced expression of the cell cycle protein cyclin D1. In summary prophylactic transdermal delivery of diclofenac to the sight of AVF cannulation prevents adverse neointimal hyperplasic remodelling and potentially offers a novel treatment option that may help prolong AVF patency and flow rates. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation

    Science.gov (United States)

    MacAskill, Mark G.; Watson, David G.; Ewart, Marie-Ann; Wadsworth, Roger; Jackson, Andrew; Aitken, Emma; MacKenzie, Graeme; Kingsmore, David; Currie, Susan; Coats, Paul

    2015-01-01

    Creation of an autologous arteriovenous fistula (AVF) for vascular access in haemodialysis is the modality of choice. However neointimal hyperplasia and loss of the luminal compartment result in AVF patency rates of ~ 60% at 12 months. The exact cause of neointimal hyperplasia in the AVF is poorly understood. Vascular trauma has long been associated with hyperplasia. With this in mind in our rabbit model of AVF we simulated cannulation autologous to that undertaken in vascular access procedures and observed significant neointimal hyperplasia as a direct consequence of cannulation. The neointimal hyperplasia was completely inhibited by topical transdermal delivery of the non-steroidal anti-inflammatory (NSAID) diclofenac. In addition to the well documented anti-inflammatory properties we have identified novel anti-proliferative mechanisms demonstrating diclofenac increases AMPK-dependent signalling and reduced expression of the cell cycle protein cyclin D1. In summary prophylactic transdermal delivery of diclofenac to the sight of AVF cannulation prevents adverse neointimal hyperplasic remodelling and potentially offers a novel treatment option that may help prolong AVF patency and flow rates. PMID:25866325

  9. FENOFIBRATE ADMINISTRATION DOES NOT AFFECT MUSCLE TRIGLYCERIDE CONCENTRATION OR INSULIN SENSITIVITY IN HUMANS

    Science.gov (United States)

    Perreault, Leigh; Bergman, Bryan C.; Hunerdosse, Devon M.; Howard, David J.; Eckel, Robert H.

    2010-01-01

    Objective Animal data suggest that males, in particular, rely on PPAR-α activity to maintain normal muscle triglyceride metabolism. We sought to examine whether this was also true in men vs. women and its relationship to insulin sensitivity. Materials/Methods Normolipidemic obese men (n=9) and women (n=9) underwent an assessment of insulin sensitivity (IVGTT) and intramuscular triglyceride metabolism (GC/MS and GC/C/IRMS from plasma and muscle biopsies taken after infusion of [U-13C]palmitate) before and after 12 weeks of fenofibrate treatment. Results Women were more insulin sensitive (Si; 5.2(0.7 vs. 2.4(0.4 ×10−4/uU/ml, W vs. M, ptriglyceride (IMTG) concentration (41.9(15.5 vs. 30.8(5.1 ug/mg dry weight, W vs. M, p=0.43), and IMTG fractional synthesis rate (FSR; 0.27(0.07 vs. 0.35(0.06/hr, W vs. M, p=0.41) as men. Fenofibrate enhanced FSR in men (0.35(0.06 to 0.54(0.06, p=0.05), with no such change seen in women (0.27(0.07 to 0.32(0.13, p=0.73), and no change in IMTG concentration in either group (23.0(3.9 in M, p=0.26 vs. baseline; 36.3(12.0 in W, p=0.79 vs. baseline). Insulin sensitivity was unaffected by fenofibrate (p>0.68). Lower percent saturation of IMTG in women vs. men before (29.1(2.3 vs. 35.2(1.7%, p=0.06) and after (27.3(2.8 vs. 35.1(1.9%, p=0.04) fenofibrate most closely related to their greater insulin sensitivity (R2=0.34, p=0.10), and was largely unchanged by the drug. Conclusions PPAR-α agonist therapy had little effect on IMTG metabolism in men or women. IMTG saturation, rather than IMTG concentration or FSR, most closely (but not significantly) related to insulin sensitivity and was unchanged by fenofibrate administration. PMID:21306746

  10. Bavachin from Psoralea corylifolia Improves Insulin-Dependent Glucose Uptake through Insulin Signaling and AMPK Activation in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Hyejin Lee

    2016-04-01

    Full Text Available The fruit of Psoralea corylifolia L. (Fabaceae (PC, known as “Bo-Gol-Zhee” in Korea has been used as traditional medicine. Ethanol and aqueous extracts of PC have an anti-hyperglycemic effect by increasing plasma insulin levels and decreasing blood glucose and total plasma cholesterol levels in type 2 diabetic rats. In this study, we purified six compounds from PC and investigated their anti-diabetic effect. Among the purified compounds, bavachin most potently accumulated lipids during adipocyte differentiation. Intracellular lipid accumulation was measured by Oil Red-O (ORO cell staining to investigate the effect of compounds on adipogenesis. Consistently, bavachin activated gene expression of adipogenic transcriptional factors, proliferator-activated receptorγ (PPARγ and CCAAT/enhancer binding protein-α (C/EBPα. Bavachin also increased adiponectin expression and secretion in adipocytes. Moreover, bavachin increased insulin-induced glucose uptake by differentiated adipocytes and myoblasts. In differentiated adipocytes, we found that bavachin enhanced glucose uptake via glucose transporter 4 (GLUT4 translocation by activating the Akt and 5′AMP-activated protein kinase (AMPK pathway in the presence or absence of insulin. These results suggest that bavachin from Psoralea corylifolia might have therapeutic potential for type 2 diabetes by activating insulin signaling pathways.

  11. AMPK, insulin resistance, and the metabolic syndrome

    OpenAIRE

    Ruderman, Neil B.; Carling, David; Prentki, Marc; Cacicedo, José M.

    2013-01-01

    Insulin resistance (IR) and hyperinsulinemia are hallmarks of the metabolic syndrome, as are central adiposity, dyslipidemia, and a predisposition to type 2 diabetes, atherosclerotic cardiovascular disease, hypertension, and certain cancers. Regular exercise and calorie restriction have long been known to increase insulin sensitivity and decrease the prevalence of these disorders. The subsequent identification of AMP-activated protein kinase (AMPK) and its activation by exercise and fuel depr...

  12. Effects of Biotin Supplementation in the Diet on Adipose Tissue cGMP Concentrations, AMPK Activation, Lipolysis, and Serum-Free Fatty Acid Levels.

    Science.gov (United States)

    Boone-Villa, Daniel; Aguilera-Méndez, Asdrubal; Miranda-Cervantes, Adriana; Fernandez-Mejia, Cristina

    2015-10-01

    Several studies have shown that pharmacological concentrations of biotin decrease hyperlipidemia. The molecular mechanisms by which pharmacological concentrations of biotin modify lipid metabolism are largely unknown. Adipose tissue plays a central role in lipid homeostasis. In the present study, we analyzed the effects of biotin supplementation in adipose tissue on signaling pathways and critical proteins that regulate lipid metabolism, as well as on lipolysis. In addition, we assessed serum fatty acid concentrations. Male BALB/cAnN Hsd mice were fed a control or a biotin-supplemented diet (control: 1.76 mg biotin/kg; supplemented: 97.7 mg biotin/kg diet) over 8 weeks postweaning. Compared with the control group, biotin-supplemented mice showed an increase in the levels of adipose guanosine 3',5'-cyclic monophosphate (cGMP) (control: 30.3±3.27 pmol/g wet tissue; supplemented: 49.5±3.44 pmol/g wet tissue) and of phosphorylated forms of adenosine 5'-monophosphate-activated protein kinase (AMPK; 65.2%±1.06%), acetyl-coenzyme A (CoA), carboxylase-1 (196%±68%), and acetyl-CoA carboxylase-2 (78.1%±18%). Serum fatty acid concentrations were decreased (control: 1.12±0.04 mM; supplemented: 0.91±0.03 mM), and no change in lipolysis was found (control: 0.29±0.05 μmol/mL; supplemented: 0.33±0.08 μmol/mL). In conclusion, 8 weeks of dietary biotin supplementation increased adipose tissue cGMP content and protein expression of the active form of AMPK and of the inactive forms of acetyl-CoA carboxylase-1 and acetyl-CoA carboxylase-2. Serum fatty acid levels fell, and no change in lipolysis was observed. These findings provide insight into the effects of biotin supplementation on adipose tissue and support its use in the treatment of dyslipidemia.

  13. A role for AMPK in the inhibition of glucose-6-phosphate dehydrogenase by polyunsaturated fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M. [Department of Biochemistry, West Virginia University, Morgantown, WV (United States); Salati, Lisa M., E-mail: lsalati@hsc.wvu.edu [Department of Biochemistry, West Virginia University, Morgantown, WV (United States)

    2009-10-09

    Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as {beta}-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser{sup 307} phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids.

  14. Metabolic regulation of neuronal plasticity by the energy sensor AMPK.

    Directory of Open Access Journals (Sweden)

    Wyatt B Potter

    Full Text Available Long Term Potentiation (LTP is a leading candidate mechanism for learning and memory and is also thought to play a role in the progression of seizures to intractable epilepsy. Maintenance of LTP requires RNA transcription, protein translation and signaling through the mammalian Target of Rapamycin (mTOR pathway. In peripheral tissue, the energy sensor AMP-activated Protein Kinase (AMPK negatively regulates the mTOR cascade upon glycolytic inhibition and cellular energy stress. We recently demonstrated that the glycolytic inhibitor 2-deoxy-D-glucose (2DG alters plasticity to retard epileptogenesis in the kindling model of epilepsy. Reduced kindling progression was associated with increased recruitment of the nuclear metabolic sensor CtBP to NRSF at the BDNF promoter. Given that energy metabolism controls mTOR through AMPK in peripheral tissue and the role of mTOR in LTP in neurons, we asked whether energy metabolism and AMPK control LTP. Using a combination of biochemical approaches and field-recordings in mouse hippocampal slices, we show that the master regulator of energy homeostasis, AMPK couples energy metabolism to LTP expression. Administration of the glycolytic inhibitor 2-deoxy-D-glucose (2DG or the mitochondrial toxin and anti-Type II Diabetes drug, metformin, or AMP mimetic AICAR results in activation of AMPK, repression of the mTOR pathway and prevents maintenance of Late-Phase LTP (L-LTP. Inhibition of AMPK by either compound-C or the ATP mimetic ara-A rescues the suppression of L-LTP by energy stress. We also show that enhanced LTP via AMPK inhibition requires mTOR signaling. These results directly link energy metabolism to plasticity in the mammalian brain and demonstrate that AMPK is a modulator of LTP. Our work opens up the possibility of using modulators of energy metabolism to control neuronal plasticity in diseases and conditions of aberrant plasticity such as epilepsy.

  15. HIGD1A Regulates Oxygen Consumption, ROS Production, and AMPK Activity during Glucose Deprivation to Modulate Cell Survival and Tumor Growth

    Directory of Open Access Journals (Sweden)

    Kurosh Ameri

    2015-02-01

    Full Text Available Hypoxia-inducible gene domain family member 1A (HIGD1A is a survival factor induced by hypoxia-inducible factor 1 (HIF-1. HIF-1 regulates many responses to oxygen deprivation, but viable cells within hypoxic perinecrotic solid tumor regions frequently lack HIF-1α. HIGD1A is induced in these HIF-deficient extreme environments and interacts with the mitochondrial electron transport chain to repress oxygen consumption, enhance AMPK activity, and lower cellular ROS levels. Importantly, HIGD1A decreases tumor growth but promotes tumor cell survival in vivo. The human Higd1a gene is located on chromosome 3p22.1, where many tumor suppressor genes reside. Consistent with this, the Higd1a gene promoter is differentially methylated in human cancers, preventing its hypoxic induction. However, when hypoxic tumor cells are confronted with glucose deprivation, DNA methyltransferase activity is inhibited, enabling HIGD1A expression, metabolic adaptation, and possible dormancy induction. Our findings therefore reveal important new roles for this family of mitochondrial proteins in cancer biology.

  16. Aspirin suppresses growth in PI3K-mutant breast cancer by activating AMPK and inhibiting mTORC1 signaling

    Science.gov (United States)

    Henry, Whitney S.; Laszewski, Tyler; Tsang, Tiffany; Beca, Francisco; Beck, Andrew H.; McAllister, Sandra S.; Toker, Alex

    2016-01-01

    Despite the high incidence of oncogenic mutations in PIK3CA, the gene encoding the catalytic subunit of phosphoinositide 3-kinase (PI3K), PI3K inhibitors have yielded little clinical benefit for breast cancer patients. Recent epidemiological studies have suggested a therapeutic benefit from aspirin intake in cancers harboring oncogenic PIK3CA. Here we show that mutant PIK3CA-expressing breast cancer cells have greater sensitivity to aspirin-mediated growth suppression than their wild-type counterparts. Aspirin decreased viability and anchorage-independent growth of mutant PIK3CA breast cancer cells independently of its effects on cyclooxygenase-2 (COX-2) and nuclear factor-kappa B (NF-κB). We ascribed the effects of aspirin to AMP-activated protein kinase (AMPK) activation, mammalian target of rapamycin complex 1 (mTORC1) inhibition, and autophagy induction. In vivo, oncogenic PIK3CA-driven mouse mammary tumors treated daily with aspirin resulted in decreased tumor growth kinetics, while combination therapy of aspirin and a PI3K inhibitor further attenuated tumor growth. Our study supports evaluation of aspirin and PI3K pathway inhibitors as combination therapy for targeting breast cancer. PMID:27940576

  17. The polyphenol extract from Sechium edule shoots inhibits lipogenesis and stimulates lipolysis via activation of AMPK signals in HepG2 cells.

    Science.gov (United States)

    Wu, Cheng-Hsun; Ou, Ting-Tsz; Chang, Chun-Hua; Chang, Xiao-Zong; Yang, Mon-Yuan; Wang, Chau-Jong

    2014-01-22

    Fatty liver may have implications for metabolic syndrome, such as obesity, hypertension, and diabetes. Therefore, the development of pharmacological or natural agents to reduce fat accumulation in the liver is an important effort. The Sechium edule shoots have already been verified to decrease serum lipids and cholesterol and prevent atherosclerosis. However, how Sechium edule shoots modulate hepatic lipid metabolism is unclear. This study was designed to investigate the effects and mechanisms of polyphenol extracts (SPE) of Sechium edule shoots in reducing lipid accumulation in oleic acid-treated HepG2 cells. We found that water extracts (SWE) of Sechium edule shoots could decrease serum and hepatic lipid contents (e.g., triacylglycerol and cholesterol). Furthermore, SWE and SPE through the AMPK (AMP-activating protein kinase) signaling pathway could decrease lipogenic relative enzymes, such as FAS (fatty acid synthase), HMGCoR (HMG-CoA reductase), and SREBPs (sterol regulatory element binding proteins), and increase the expression of CPT-I (carnitine palmitoyltransferase I) and PPARα (peroxisome proliferators activated receptor α), which are critical regulators of hepatic lipid metabolism. These observations suggested that Sechium edule shoots have potential for developing health foods for preventing and remedying fatty liver.

  18. AMPK regulates metabolic actions of glucocorticoids by phosphorylating the glucocorticoid receptor through p38 MAPK.

    Science.gov (United States)

    Nader, Nancy; Ng, Sinnie Sin Man; Lambrou, George I; Pervanidou, Panagiota; Wang, Yonghong; Chrousos, George P; Kino, Tomoshige

    2010-09-01

    Glucocorticoids play central roles in the regulation of energy metabolism by shifting it toward catabolism, whereas AMP-activated protein kinase (AMPK) is the master regulator of energy homeostasis, sensing energy depletion and stimulating pathways of increasing fuel uptake and saving on peripheral supplies. We showed here that AMPK regulates glucocorticoid actions on carbohydrate metabolism by targeting the glucocorticoid receptor (GR) and modifying transcription of glucocorticoid-responsive genes in a tissue- and promoter-specific fashion. Activation of AMPK in rats reversed glucocorticoid-induced hepatic steatosis and suppressed glucocorticoid-mediated stimulation of glucose metabolism. Transcriptomic analysis in the liver suggested marked overlaps between the AMPK and glucocorticoid signaling pathways directed mostly from AMPK to glucocorticoid actions. AMPK accomplishes this by phosphorylating serine 211 of the human GR indirectly through phosphorylation and consequent activation of p38 MAPK and by altering attraction of transcriptional coregulators to DNA-bound GR. In human peripheral mononuclear cells, AMPK mRNA expression positively correlated with that of glucocorticoid-responsive glucocorticoid-inducible leucine zipper protein, which correlated also positively with the body mass index of subjects. These results indicate that the AMPK-mediated energy control system modulates glucocorticoid action at target tissues. Because increased action of glucocorticoids is associated with the development of metabolic disorders, activation of AMPK could be a promising target for developing pharmacological interventions to these pathologies.

  19. A kinome RNAi screen identified AMPK as promoting poxvirus entry through the control of actin dynamics.

    Directory of Open Access Journals (Sweden)

    Theresa S Moser

    2010-06-01

    Full Text Available Poxviruses include medically important human pathogens, yet little is known about the specific cellular factors essential for their replication. To identify genes essential for poxvirus infection, we used high-throughput RNA interference to screen the Drosophila kinome for factors required for vaccinia infection. We identified seven genes including the three subunits of AMPK as promoting vaccinia infection. AMPK not only facilitated infection in insect cells, but also in mammalian cells. Moreover, we found that AMPK is required for macropinocytosis, a major endocytic entry pathway for vaccinia. Furthermore, we show that AMPK contributes to other virus-independent actin-dependent processes including lamellipodia formation and wound healing, independent of the known AMPK activators LKB1 and CaMKK. Therefore, AMPK plays a highly conserved role in poxvirus infection and actin dynamics independent of its role as an energy regulator.

  20. Studying AMPK in an Evolutionary Context.

    Science.gov (United States)

    Jain, Arpit; Roustan, Valentin; Weckwerth, Wolfram; Ebersberger, Ingo

    2018-01-01

    The AMPK protein kinase forms the heart of a complex network controlling the metabolic activities in a eukaryotic cell. Unraveling the steps by which this pathway evolved from its primordial roots in the last eukaryotic common ancestor to its present status in contemporary species has the potential to shed light on the evolution of eukaryotes. A homolog search for the proteins interacting in this pathway is considerably straightforward. However, interpreting the results, when reconstructing the evolutionary history of the pathway over larger evolutionary distances, bears a number of pitfalls. With this in mind, we present a protocol to trace a metabolic pathway across contemporary species and backward in evolutionary time. Alongside the individual analysis steps, we provide guidelines for data interpretation generalizing beyond the analysis of AMPK.

  1. Leucine Modulates Mitochondrial Biogenesis and SIRT1-AMPK Signaling in C2C12 Myotubes

    Directory of Open Access Journals (Sweden)

    Chunzi Liang

    2014-01-01

    Full Text Available Previous studies from this laboratory demonstrate that dietary leucine protects against high fat diet-induced mitochondrial impairments and stimulates mitochondrial biogenesis and energy partitioning from adipocytes to muscle cells through SIRT1-mediated mechanisms. Moreover, β-hydroxy-β-methyl butyrate (HMB, a metabolite of leucine, has been reported to activate AMPK synergistically with resveratrol in C2C12 myotubes. Therefore, we hypothesize that leucine-induced activation of SIRT1 and AMPK is the central event that links the upregulated mitochondrial biogenesis and fatty acid oxidation in skeletal muscle. Thus, C2C12 myotubes were treated with leucine (0.5 mM, alanine (0.5 mM, valine (0.5 mM, EX527 (SIRT1 inhibitor, 25 μM, and Compound C (AMPK inhibitor, 25 μM alone or in combination to determine the roles of AMPK and SIRT1 in leucine-modulation of energy metabolism. Leucine significantly increased mitochondrial content, mitochondrial biogenesis-related genes expression, fatty acid oxidation, SIRT1 activity and gene expression, and AMPK phosphorylation in C2C12 myotubes compared to the controls, while EX527 and Compound C markedly attenuated these effects. Furthermore, leucine treatment for 24 hours resulted in time-dependent increases in cellular NAD+, SIRT1 activity, and p-AMPK level, with SIRT1 activation preceding that of AMPK, indicating that leucine activation of SIRT1, rather than AMPK, is the primary event.

  2. Absence of RIP140 reveals a pathway regulating glut4-dependent glucose uptake in oxidative skeletal muscle through UCP1-mediated activation of AMPK.

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    Asmaà Fritah

    Full Text Available Skeletal muscle constitutes the major site of glucose uptake leading to increased removal of glucose from the circulation in response to insulin. Type 2 diabetes and obesity are often associated with insulin resistance that can be counteracted by exercise or the use of drugs increasing the relative proportion of oxidative fibers. RIP140 is a transcriptional coregulator with a central role in metabolic tissues and we tested the effect of modulating its level of expression on muscle glucose and lipid metabolism in two mice models. Here, we show that although RIP140 protein is expressed at the same level in both oxidative and glycolytic muscles, it inhibits both fatty acid and glucose utilization in a fiber-type dependent manner. In RIP140-null mice, fatty acid utilization increases in the extensor digitorum longus and this is associated with elevated expression of genes implicated in fatty acid binding and transport. In the RIP140-null soleus, depletion of RIP140 leads to increased GLUT4 trafficking and glucose uptake with no change in Akt activity. AMPK phosphorylation/activity is inhibited in the soleus of RIP140 transgenic mice and increased in RIP140-null soleus. This is associated with increased UCP1 expression and mitochondrial uncoupling revealing the existence of a signaling pathway controlling insulin-independent glucose uptake in the soleus of RIP140-null mice. In conclusion, our findings reinforce the participation of RIP140 in the maintenance of energy homeostasis by acting as an inhibitor of energy production and particularly point to RIP140 as a promising therapeutic target in the treatment of insulin resistance.

  3. Combination of deep sea water andSesamum indicumleaf extract prevents high-fat diet-induced obesity through AMPK activation in visceral adipose tissue.

    Science.gov (United States)

    Yuan, Haidan; Chung, Sunghyun; Ma, Qianqian; Ye, L I; Piao, Guangchun

    2016-01-01

    The aim of the present study was to evaluate the protective effects of a combination of deep sea water (DSW) and Sesamum indicum leaf extract (SIE) against high-fat diet (HFD)-induced obesity and investigate its molecular mechanisms in adipose tissue. ICR mice were randomly divided into three groups: HFD control (HFC), DSW and DSW + 125 mg/kg SIE (DSS) groups. The mice in the HFC group had free access to drinking water while those in the DSW and DSS groups had free access to DSW. The mice in the DSS group were treated with SIE once per day for 8 weeks. The mice in all three groups were allowed to freely access a HFD. Compared with the HFC group, the DSS group showed lower body weight gain and serum levels of glucose, triglycerides and leptin. Histological analyses of the epididymal white, retroperitoneal white and scapular brown adipose tissue of mice in the DSS group revealed that the adipocytes were markedly decreased in size compared with those in the HFC group. Moreover, DSS significantly increased the levels of phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase (ACC) in mice epididymal adipose tissues. Furthermore, DSS upregulated the expression levels of lipolysis-associated mRNA, specifically peroxisome proliferator-activated receptor-α (PPAR-α) and cluster of differentiation 36 (CD36), and energy expenditure-associated mRNA, namely uncoupling protein 2 (UCP2) and carnitine palmitoyltransferase-1 (CPT1) in the epididymal adipose tissues. By contrast, DSS suppressed the expression of the lipogenesis-related gene sterol regulatory element-binding protein-1 (SREBP1) at the mRNA level. These results suggest that DSS is effective for suppressing body weight gain and enhancing the lipid profile.

  4. Combination of deep sea water and Sesamum indicum leaf extract prevents high-fat diet-induced obesity through AMPK activation in visceral adipose tissue

    Science.gov (United States)

    YUAN, HAIDAN; CHUNG, SUNGHYUN; MA, QIANQIAN; YE, LI; PIAO, GUANGCHUN

    2016-01-01

    The aim of the present study was to evaluate the protective effects of a combination of deep sea water (DSW) and Sesamum indicum leaf extract (SIE) against high-fat diet (HFD)-induced obesity and investigate its molecular mechanisms in adipose tissue. ICR mice were randomly divided into three groups: HFD control (HFC), DSW and DSW + 125 mg/kg SIE (DSS) groups. The mice in the HFC group had free access to drinking water while those in the DSW and DSS groups had free access to DSW. The mice in the DSS group were treated with SIE once per day for 8 weeks. The mice in all three groups were allowed to freely access a HFD. Compared with the HFC group, the DSS group showed lower body weight gain and serum levels of glucose, triglycerides and leptin. Histological analyses of the epididymal white, retroperitoneal white and scapular brown adipose tissue of mice in the DSS group revealed that the adipocytes were markedly decreased in size compared with those in the HFC group. Moreover, DSS significantly increased the levels of phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase (ACC) in mice epididymal adipose tissues. Furthermore, DSS upregulated the expression levels of lipolysis-associated mRNA, specifically peroxisome proliferator-activated receptor-α (PPAR-α) and cluster of differentiation 36 (CD36), and energy expenditure-associated mRNA, namely uncoupling protein 2 (UCP2) and carnitine palmitoyltransferase-1 (CPT1) in the epididymal adipose tissues. By contrast, DSS suppressed the expression of the lipogenesis-related gene sterol regulatory element-binding protein-1 (SREBP1) at the mRNA level. These results suggest that DSS is effective for suppressing body weight gain and enhancing the lipid profile. PMID:26889265

  5. AMPK induces vascular smooth muscle cell senescence via LKB1 dependent pathway

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jin Young; Woo, Chang-Hoon [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Aging-associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Kang, Young Jin; Lee, Kwang Youn [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Hyoung Chul, E-mail: hcchoi@med.yu.ac.kr [Department of Pharmacology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Aging-associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of)

    2011-09-16

    Highlights: {yields} An aging model was established by stimulating VSMC with adriamycin. {yields} Adriamycin increased p-LKB1, p-AMPK, p53 and p21 expressions. {yields} Inhibition of AMPK diminished SA-{beta}-gal staining and restored VSMC proliferation. {yields} p53 and p21 siRNA attenuated adriamycin-induced SA-{beta}-gal staining in VSMC. {yields} p53-p21 pathway is a mediator of LKB1/AMPK induced VSMC senescence. -- Abstract: Vascular cells have a limited lifespan with limited cell proliferation and undergo cellular senescence. The functional changes associated with cellular senescence are thought to contribute to age-related vascular disorders. AMP-activated protein kinase (AMPK) has been discussed in terms of beneficial or harmful effects for aging-related diseases. However, the detailed functional mechanisms of AMPK are largely unclear. An aging model was established by stimulating vascular smooth muscle cell (VSMC) with adriamycin. Adriamycin progressively increased the mRNA and protein expressions of AMPK. The phosphorylation levels of LKB1 and acetyl-CoA carboxylase (ACC), the upstream and downstream of AMPK, were dramatically increased by adriamycin stimulation. The expressions of p53 and p21, which contribute to vascular senescence, were also increased. Inhibition of AMPK diminished senescence-associated {beta}-galactosidase (SA-{beta}-gal) staining, and restored VSMC proliferation. Cytosolic translocation of LKB1 by adriamycin could be a mechanism for AMPK activation in senescence. Furthermore, p53 siRNA and p21 siRNA transfection attenuated adriamycin-induced SA-{beta}-gal staining. These results suggest that LKB1 dependent AMPK activation elicits VSMC senescence and p53-p21 pathway is a mediator of LKB1/AMPK-induced senescence.

  6. AMPK controls exercise endurance, mitochondrial oxidative capacity, and skeletal muscle integrity

    DEFF Research Database (Denmark)

    Lantier, Louise; Fentz, Joachim; Mounier, Rémi

    2014-01-01

    AMP-activated protein kinase (AMPK) is a sensor of cellular energy status that plays a central role in skeletal muscle metabolism. We used skeletal muscle-specific AMPKα1α2 double-knockout (mdKO) mice to provide direct genetic evidence of the physiological importance of AMPK in regulating muscle ...... integrity....

  7. Understanding the solid-state forms of fenofibrate - A spectroscopic and computational study

    DEFF Research Database (Denmark)

    Heinz, Andrea; Gordon, Keith C.; McGoverin, Cushla M.

    2009-01-01

    The aim of this study was to investigate the structure of different solid-state forms of fenofibrate, a drug that lacks strong intermolecular interactions such as hydrogen bonding. In addition to a structural analysis of crystalline and amorphous fenofibrate using infrared and Raman spectroscopy...... combined with density functional theory calculations [B3LYP 6-31G(d)], solid-state changes that occur upon recrystallization of amorphous fenofibrate were monitored and described using in situ Raman spectroscopy. A comparison of the calculated vibrational spectra of a fenofibrate monomer and two dimer...... structures with the experimental vibrational spectra of crystalline and amorphous fenofibrate revealed conformational differences in the orientation of the two benzyl rings in the fenofibrate molecule and structural differences between the different solid-state forms in aliphatic parts of the drug molecule...

  8. Estradiol Regulates Brown Adipose Tissue Thermogenesis via Hypothalamic AMPK

    Science.gov (United States)

    Martínez de Morentin, Pablo B.; González-García, Ismael; Martins, Luís; Lage, Ricardo; Fernández-Mallo, Diana; Martínez-Sánchez, Noelia; Ruíz-Pino, Francisco; Liu, Ji; Morgan, Donald A.; Pinilla, Leonor; Gallego, Rosalía; Saha, Asish K.; Kalsbeek, Andries; Fliers, Eric; Bisschop, Peter H.; Diéguez, Carlos; Nogueiras, Rubén; Rahmouni, Kamal; Tena-Sempere, Manuel; López, Miguel

    2014-01-01

    Summary Estrogens play a major role in the modulation of energy balance through central and peripheral actions. Here, we demonstrate that central action of estradiol (E2) inhibits AMP-activated protein kinase (AMPK) through estrogen receptor alpha (ERα) selectively in the ventromedial nucleus of the hypothalamus (VMH), leading to activation of thermogenesis in brown adipose tissue (BAT) through the sympathetic nervous system (SNS) in a feeding-independent manner. Genetic activation of AMPK in the VMH prevented E2-induced increase in BAT-mediated thermogenesis and weight loss. Notably, fluctuations in E2 levels during estrous cycle also modulate this integrated physiological network. Together, these findings demonstrate that E2 regulation of the VMH AMPK-SNS-BAT axis is an important determinant of energy balance and suggest that dysregulation in this axis may account for the common changes in energy homeostasis and obesity linked to dysfunction of the female gonadal axis. PMID:24856932

  9. Black soybean extract improves lipid profiles in fenofibrate-treated type 2 diabetics with postprandial hyperlipidemia.

    Science.gov (United States)

    Kusunoki, Masataka; Sato, Daisuke; Tsutsumi, Kazuhiko; Tsutsui, Hideyo; Nakamura, Takao; Oshida, Yoshiharu

    2015-06-01

    Black soybeans (Glycine max (L.) Merr.) are known to be rich in polyphenols, including anthocyanins, and they have been consumed since ancient times for their beneficial effects on health. In addition, it has been reported that black soybean (BS) seed coat may ameliorate obesity and insulin resistance. In the present study, we administered BS extract to type 2 diabetics for 2 months to investigate the effects of BS on glycemic control and lipid metabolism parameters. In addition, we administered BS and antihyperlipidemic agent, fenofibrate, to patients with type 2 diabetes complicated by postprandial hyperlipidemia for 2 months and assessed the combined effects of fenofibrate and BS on serum lipid profile. The results showed that administration of the BS alone had no effect on the blood glucose or lipid levels, but that administration of fenofibrate alone and fenofibrate in combination with the BS significantly lowered their serum triglyceride (TG) level at fasting state, and the percent decrease in the serum TG level after combined administration was significantly higher than in the subjects who received fenofibrate alone. Furthermore, the serum LDL cholesterol concentration, which did not decrease when fenofibrate was administered alone, decreased significantly when the BS and fenofibrate were administered in combination. These results suggest that combined administration of the BS with fenofibrate enhanced the antihyperlipidemic action of fenofibrate, and the results of this study demonstrated the usefulness of the BS in clinical practice.

  10. Dynamic dissolution-/permeation-testing of nano- and microparticle formulations of fenofibrate

    DEFF Research Database (Denmark)

    Sironi, Daniel; Rosenberg, Jörg; Bauer-Brandl, Annette

    2017-01-01

    The aim of the current study was to evaluate a dynamic dissolution-/permeation-system for prediction of gastrointestinal and absorption-behavior of two commercial fenofibrate formulations. To this end, both dissolution and barrier-flux were followed simultaneously for fenofibrate powder, a microp......The aim of the current study was to evaluate a dynamic dissolution-/permeation-system for prediction of gastrointestinal and absorption-behavior of two commercial fenofibrate formulations. To this end, both dissolution and barrier-flux were followed simultaneously for fenofibrate powder...

  11. Hyperlipidemia-associated pancreatitis in pregnancy managed with fenofibrate.

    Science.gov (United States)

    Whitten, Amy E; Lorenz, Robert P; Smith, Joann M

    2011-02-01

    Pancreatitis is a concerning clinical event during pregnancy, with high morbidity and mortality rates for mother and fetus. Hypertriglyceridemia is considered a rare cause of pancreatitis in pregnancy, with the majority of reported cases being associated with the lipid metabolism disorders. We report on a case of hypertriglyceridemia-induced pancreatitis in a woman presenting at 32 weeks of gestational age. Her dyslipidemia was not controlled with diet alone, necessitating medical intervention. Fenofibrate was used successfully. Recurrence of pancreatitis during the pregnancy was avoided, and a healthy neonate was delivered at 35 weeks of gestation. Fenofibrate was used safely and successfully during pregnancy in this case of hypertriglyceridemia-associated pancreatitis refractory to conservative measures.

  12. Preventive Effects of Velvet Antler (Cervus elaphus against Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting MAPK/NF-κB Activation and Inducing AMPK/Nrf2 Pathways

    Directory of Open Access Journals (Sweden)

    Jui-Shu Chang

    2018-01-01

    Full Text Available Velvet antler (Cervus elaphus is a typical traditional animal medicine. It is considered to have various pharmacological effects including stimulation of the immune system, increase in the physical strength, and enhancement of sexual function. This paper aims to investigate the aqueous extract of velvet antler (AVA in the mouse models of LPS-induced ALI. Inhibition of NO, TNF-α, IL-1β, IL-6, and IL-10 productions contributes to the attenuation of LPS-induced lung inflammation by AVA. A 5-day pretreatment of AVA prevented histological alterations and enhanced antioxidant enzyme activity in lung tissues. AVA significantly reduced the material (total number of cells and proteins in the BALF. Western blot analysis revealed that the expression of iNOS and COX-2 and phosphorylation of IκB-α and MAPKs proteins are blocked in LPS-stimulated macrophages as well as LPS-induced lung injury in mice. Consistent with this concept, the phosphorylation of CaMKKβ, LKB1, AMPK, Nrf2, and HO-1 was activated after AVA treatment. The results from this study indicate AVA has anti-inflammatory effects in vivo and AVA is a potential model for the development of health food. In addition, its pathways may be at least partially associated with inhibiting MAPK/NF-κB activation and upregulating AMPK/Nrf2 pathways and the regulation of antioxidant enzyme activity.

  13. Metformin inhibits inflammatory response via AMPK-PTEN pathway in vascular smooth muscle cells

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    Kim, Sun Ae [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Hyoung Chul, E-mail: hcchoi@med.yu.ac.kr [Department of Pharmacology, Aging-Associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. Black-Right-Pointing-Pointer Metformin suppressed TNF-{alpha}-induced COX-2 and iNOS mRNA expression. Black-Right-Pointing-Pointer Compound C and bpv (pic) increased iNOS and COX-2 protein expression. Black-Right-Pointing-Pointer NF-{kappa}B activation was restored by inhibiting AMPK and PTEN. Black-Right-Pointing-Pointer AMPK and PTEN regulated TNF-{alpha}-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK-PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 {mu}M) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-{alpha}) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-{kappa}B. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-{kappa}B activation decreased in response to metformin and was restored by inhibiting AMPK

  14. Thiamine deficiency induces anorexia by inhibiting hypothalamic AMPK.

    Science.gov (United States)

    Liu, M; Alimov, A P; Wang, H; Frank, J A; Katz, W; Xu, M; Ke, Z-J; Luo, J

    2014-05-16

    Obesity and eating disorders are prevailing health concerns worldwide. It is important to understand the regulation of food intake and energy metabolism. Thiamine (vitamin B1) is an essential nutrient. Thiamine deficiency (TD) can cause a number of disorders in humans, such as Beriberi and Wernicke-Korsakoff syndrome. We demonstrated here that TD caused anorexia in C57BL/6 mice. After feeding a TD diet for 16days, the mice displayed a significant decrease in food intake and an increase in resting energy expenditure (REE), which resulted in a severe weight loss. At the 22nd day, the food intake was reduced by 69% and 74% for male and female mice, respectively in TD group. The REE increased by ninefolds in TD group. The loss of body weight (17-24%) was similar between male and female animals and mainly resulted from the reduction of fat mass (49% decrease). Re-supplementation of thiamine (benfotiamine) restored animal's appetite, leading to a total recovery of body weight. The hypothalamic adenosine monophosphate-activated protein kinase (AMPK) is a critical regulator of food intake. TD inhibited the phosphorylation of AMPK in the arcuate nucleus (ARN) and paraventricular nucleus (PVN) of the hypothalamus without affecting its expression. TD-induced inhibition of AMPK phosphorylation was reversed once thiamine was re-supplemented. In contrast, TD increased AMPK phosphorylation in the skeletal muscle and upregulated the uncoupling protein (UCP)-1 in brown adipose tissues which was consistent with increased basal energy expenditure. Re-administration of thiamine stabilized AMPK phosphorylation in the skeletal muscle as well as energy expenditure. Taken together, TD may induce anorexia by inhibiting hypothalamic AMPK activity. With a simultaneous increase in energy expenditure, TD caused an overall body weight loss. The results suggest that the status of thiamine levels in the body may affect food intake and body weight. Copyright © 2014 IBRO. Published by Elsevier Ltd

  15. AMPK Maintains Cellular Metabolic Homeostasis through Regulation of Mitochondrial Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Rebecca C. Rabinovitch

    2017-10-01

    Full Text Available Reactive oxygen species (ROS are continuously produced as a by-product of mitochondrial metabolism and eliminated via antioxidant systems. Regulation of mitochondrially produced ROS is required for proper cellular function, adaptation to metabolic stress, and bypassing cellular senescence. Here, we report non-canonical regulation of the cellular energy sensor AMP-activated protein kinase (AMPK by mitochondrial ROS (mROS that functions to maintain cellular metabolic homeostasis. We demonstrate that mitochondrial ROS are a physiological activator of AMPK and that AMPK activation triggers a PGC-1α-dependent antioxidant response that limits mitochondrial ROS production. Cells lacking AMPK activity display increased mitochondrial ROS levels and undergo premature senescence. Finally, we show that AMPK-PGC-1α-dependent control of mitochondrial ROS regulates HIF-1α stabilization and that mitochondrial ROS promote the Warburg effect in cells lacking AMPK signaling. These data highlight a key function for AMPK in sensing and resolving mitochondrial ROS for stress resistance and maintaining cellular metabolic balance.

  16. Ghrelin-AMPK Signaling Mediates the Neuroprotective Effects of Calorie Restriction in Parkinson's Disease

    Science.gov (United States)

    Bayliss, Jacqueline A.; Lemus, Moyra B.; Stark, Romana; Santos, Vanessa V.; Thompson, Aiysha; Rees, Daniel J.; Galic, Sandra; Elsworth, John D.; Kemp, Bruce E.; Davies, Jeffrey S.

    2016-01-01

    Calorie restriction (CR) is neuroprotective in Parkinson's disease (PD) although the mechanisms are unknown. In this study we hypothesized that elevated ghrelin, a gut hormone with neuroprotective properties, during CR prevents neurodegeneration in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD. CR attenuated the MPTP-induced loss of substantia nigra (SN) dopamine neurons and striatal dopamine turnover in ghrelin WT but not KO mice, demonstrating that ghrelin mediates CR's neuroprotective effect. CR elevated phosphorylated AMPK and ACC levels in the striatum of WT but not KO mice suggesting that AMPK is a target for ghrelin-induced neuroprotection. Indeed, exogenous ghrelin significantly increased pAMPK in the SN. Genetic deletion of AMPKβ1 and 2 subunits only in dopamine neurons prevented ghrelin-induced AMPK phosphorylation and neuroprotection. Hence, ghrelin signaling through AMPK in SN dopamine neurons mediates CR's neuroprotective effects. We consider targeting AMPK in dopamine neurons may recapitulate neuroprotective effects of CR without requiring dietary intervention. SIGNIFICANCE STATEMENT The neuroprotective mechanisms of calorie restriction (CR) in Parkinson's disease are unknown. Indeed, the difficulty to adhere to CR necessitates an alternative method to recapitulate the neuroprotective benefits of CR while bypassing dietary constraints. Here we show that CR increases plasma ghrelin, which targets substantia nigra dopamine to maintain neuronal survival. Selective deletion on AMPK beta1 and beta2 subunits only in DAT cre-expressing neurons shows that the ghrelin-induced neuroprotection requires activation of AMPK in substantia nigra dopamine neurons. We have discovered ghrelin as a key metabolic signal, and AMPK in dopamine neurons as its target, which links calorie restriction with neuroprotection in Parkinson's disease. Thus, targeting AMPK in dopamine neurons may provide novel neuroprotective benefits in Parkinson's disease. PMID

  17. Central exercise action increases the AMPK and mTOR response to leptin.

    Directory of Open Access Journals (Sweden)

    Eduardo R Ropelle

    Full Text Available AMP-activated protein kinase (AMPK and mammalian Target of Rapamycin (mTOR are key regulators of cellular energy balance and of the effects of leptin on food intake. Acute exercise is associated with increased sensitivity to the effects of leptin on food intake in an IL-6-dependent manner. To determine whether exercise ameliorates the AMPK and mTOR response to leptin in the hypothalamus in an IL-6-dependent manner, rats performed two 3-h exercise bouts, separated by one 45-min rest period. Intracerebroventricular IL-6 infusion reduced food intake and pretreatment with AMPK activators and mTOR inhibitor prevented IL-6-induced anorexia. Activators of AMPK and fasting increased food intake in control rats to a greater extent than that observed in exercised ones, whereas inhibitor of AMPK had the opposite effect. Furthermore, the reduction of AMPK and ACC phosphorylation and increase in phosphorylation of proteins involved in mTOR signal transduction, observed in the hypothalamus after leptin infusion, were more pronounced in both lean and diet-induced obesity rats after acute exercise. Treatment with leptin reduced food intake in exercised rats that were pretreated with vehicle, although no increase in responsiveness to leptin-induced anorexia after pretreatment with anti-IL6 antibody, AICAR or Rapamycin was detected. Thus, the effects of leptin on the AMPK/mTOR pathway, potentiated by acute exercise, may contribute to appetite suppressive actions in the hypothalamus.

  18. Effect of Petiveria alliacea Leaves Extract in Decreasing Serum Level of Blood Glucose Level Through Activation of AMPK-α1 in Diabetes Mellitus Rat Models

    Directory of Open Access Journals (Sweden)

    Arifa Mustika

    2017-03-01

    Full Text Available Singawalang (Petiveria alliaceae is a medicinal herb that is used traditionally as folk medicine for various diseases. The plant has been used as an antidiabetic agent in Indonesian society. Until now, the effect and mechanism of action of Petiveria alliaceae as antidiabetic agent is not clear. The aim of the study was to determine the effect of Petiveria alliaceae to blood glucose level and to identify expression of AMPK-α1 in rat liver. The research was experimental study with randomized and was conducted at Laboratory Pharmacology and Therapy, and Laboratory Patology Anatomy, Faculty of Medicine, Universitas Airlangga, on April until August 2015. Twenty five male rats were injected by Streptozotocin to create diabetic rat models and randomly divided into 5 groups. The group 1, 2 and 3 are treatment groups that were given the ethanol extract of Petiveria alliaceae at dose 90 mg/kgbw, 180 mg/kgbw, and 360 mg/kgbw, orally, once daily for fourteen days. The fourth group is a negative control who were given distilled water and the fifth group is a positive control who were given metformin at dose 150 mg/kgbw. On the 15th day, blood glucose level were measured by glucometer and the rats were sacrificed to collect the liver. Expression of AMPK-α1 were assessed by immunohistochemistry. Data were analyzed by ANAVA and Wilcoxon (α=0,05. The results have been showed that there were significant differences in glucose blood level between negative control with the group were given the extract at dose 90 mg/kgbw, 360 mg/kgbw and positive control, between dose 180 mg/kgbw with dose 360 mg/kgbw and positive control. A significant differences of expression of AMPK-α1 showed between dose 180 mg/kgbw with dose 360 mg/kgbw and positive control. The conclusion of this study was the extract ethanol of Singawalang leaves reduce blood glucose level in diabetes mellitus rat models through increase in the expression of AMPK-α1.

  19. Dystrophin-glycoprotein complex regulates muscle nitric oxide production through mechanoregulation of AMPK signaling.

    Science.gov (United States)

    Garbincius, Joanne F; Michele, Daniel E

    2015-11-03

    Patients deficient in dystrophin, a protein that links the cytoskeleton to the extracellular matrix via the dystrophin-glycoprotein complex (DGC), exhibit muscular dystrophy, cardiomyopathy, and impaired muscle nitric oxide (NO) production. We used live-cell NO imaging and in vitro cyclic stretch of isolated adult mouse cardiomyocytes as a model system to investigate if and how the DGC directly regulates the mechanical activation of muscle NO signaling. Acute activation of NO synthesis by mechanical stretch was impaired in dystrophin-deficient mdx cardiomyocytes, accompanied by loss of stretch-induced neuronal NO synthase (nNOS) S1412 phosphorylation. Intriguingly, stretch induced the acute activation of AMP-activated protein kinase (AMPK) in normal cardiomyocytes but not in mdx cardiomyocytes, and specific inhibition of AMPK was sufficient to attenuate mechanoactivation of NO production. Therefore, we tested whether direct pharmacologic activation of AMPK could bypass defective mechanical signaling to restore nNOS activity in dystrophin-deficient cardiomyocytes. Indeed, activation of AMPK with 5-aminoimidazole-4-carboxamide riboside or salicylate increased nNOS S1412 phosphorylation and was sufficient to enhance NO production in mdx cardiomyocytes. We conclude that the DGC promotes the mechanical activation of cardiac nNOS by acting as a mechanosensor to regulate AMPK activity, and that pharmacologic AMPK activation may be a suitable therapeutic strategy for restoring nNOS activity in dystrophin-deficient hearts and muscle.

  20. AMPK Protects Leukemia-Initiating Cells in Myeloid Leukemias from Metabolic Stress in the Bone Marrow.

    Science.gov (United States)

    Saito, Yusuke; Chapple, Richard H; Lin, Angelique; Kitano, Ayumi; Nakada, Daisuke

    2015-11-05

    How cancer cells adapt to metabolically adverse conditions in patients and strive to proliferate is a fundamental question in cancer biology. Here we show that AMP-activated protein kinase (AMPK), a metabolic checkpoint kinase, confers metabolic stress resistance to leukemia-initiating cells (LICs) and promotes leukemogenesis. Upon dietary restriction, MLL-AF9-induced murine acute myeloid leukemia (AML) activated AMPK and maintained leukemogenic potential. AMPK deletion significantly delayed leukemogenesis and depleted LICs by reducing the expression of glucose transporter 1 (Glut1), compromising glucose flux, and increasing oxidative stress and DNA damage. LICs were particularly dependent on AMPK to suppress oxidative stress in the hypoglycemic bone marrow environment. Strikingly, AMPK inhibition synergized with physiological metabolic stress caused by dietary restriction and profoundly suppressed leukemogenesis. Our results indicate that AMPK protects LICs from metabolic stress and that combining AMPK inhibition with physiological metabolic stress potently suppresses AML by inducing oxidative stress and DNA damage. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. FAK tyrosine phosphorylation is regulated by AMPK and controls metabolism in human skeletal muscle

    DEFF Research Database (Denmark)

    Lassiter, David G; Nylén, Carolina; Sjögren, Rasmus J O

    2018-01-01

    and the direct role of FAK on glucose and lipid metabolism. We hypothesised that insulin treatment and AMPK activation would have opposing effects on FAK phosphorylation and that gene silencing of FAK would alter metabolism. METHODS: Human muscle was treated with insulin or the AMPK-activating compound 5......-aminoimadazole-4-carboxamide ribonucleotide (AICAR) to determine FAK phosphorylation and glucose transport. Primary human skeletal muscle cells were used to study the effects of insulin or AICAR treatment on FAK signalling during serum starvation, as well as to determine the metabolic consequences of silencing...... in various non-muscle cell types and plays a regulatory role during skeletal muscle differentiation. The role of FAK in skeletal muscle in relation to insulin stimulation or AMPK activation is unknown. We examined the effects of insulin or AMPK activation on FAK phosphorylation in human skeletal muscle...

  2. Fenofibrate Therapy in Carnitine Palmitoyl Transferase Type 2 Deficiency

    Directory of Open Access Journals (Sweden)

    I. Hamilton-Craig

    2012-01-01

    Full Text Available Bezafibrate therapy has been shown to improve beta-oxidation of fatty acids and to reduce episodes of rhabdomyolysis in patients with carnitine palmitoyltransferase type-2 (CPT2 deficiency. We report the efficacy of fenofibrate in a patient with CPT2 deficiency, in whom beta-oxidation was improved but an episode of rhabdomyolysis nevertheless occurred. This suggests additional methods to avoid rhabdomyolysis in patients with CPT2 deficiency should accompany fibrate therapy, including avoidance of muscular overexertion, dehydration, and heat exposure.

  3. Nutrient Excess and AMPK Downregulation in Incubated Skeletal Muscle and Muscle of Glucose Infused Rats.

    Directory of Open Access Journals (Sweden)

    Kimberly A Coughlan

    Full Text Available We have previously shown that incubation for 1h with excess glucose or leucine causes insulin resistance in rat extensor digitorum longus (EDL muscle by inhibiting AMP-activated protein kinase (AMPK. To examine the events that precede and follow these changes, studies were performed in rat EDL incubated with elevated levels of glucose or leucine for 30min-2h. Incubation in high glucose (25mM or leucine (100μM significantly diminished AMPK activity by 50% within 30min, with further decreases occurring at 1 and 2h. The initial decrease in activity at 30min coincided with a significant increase in muscle glycogen. The subsequent decreases at 1h were accompanied by phosphorylation of αAMPK at Ser485/491, and at 2h by decreased SIRT1 expression and increased PP2A activity, all of which have previously been shown to diminish AMPK activity. Glucose infusion in vivo, which caused several fold increases in plasma glucose and insulin, produced similar changes but with different timing. Thus, the initial decrease in AMPK activity observed at 3h was associated with changes in Ser485/491 phosphorylation and SIRT1 expression and increased PP2A activity was a later event. These findings suggest that both ex vivo and in vivo, multiple factors contribute to fuel-induced decreases in AMPK activity in skeletal muscle and the insulin resistance that accompanies it.

  4. AMPK couples plasma renin to cellular metabolism by phosphorylation of ACC1

    OpenAIRE

    Fraser, Scott A.; Choy, Suet-Wan; Pastor-Soler, Núria M.; Li, Hui; Davies, Matthew R. P.; Cook, Natasha; Katerelos, Marina; Mount, Peter F.; Gleich, Kurt; McRae, Jennifer L.; Dwyer, Karen M.; van Denderen, Bryce J. W.; Hallows, Kenneth R.; Kemp, Bruce E.; Power, David A.

    2013-01-01

    Salt reabsorption is the major energy-requiring process in the kidney, and AMP-activated protein kinase (AMPK) is an important regulator of cellular metabolism. Mice with targeted deletion of the β1-subunit of AMPK (AMPK-β1−/− mice) had significantly increased urinary Na+ excretion on a normal salt diet. This was associated with reduced expression of the β-subunit of the epithelial Na+ channel (ENaC) and increased subapical tubular expression of kidney-specific Na+-K+-2Cl− cotransporter 2 (NK...

  5. Berberine regulates neurite outgrowth through AMPK-dependent pathways by lowering energy status

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiaqi; Cao, Yuanzhao; Cheng, Kuoyuan; Xu, Bo; Wang, Tianchang; Yang, Qi; Yang, Qin [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China); Feng, Xudong, E-mail: xudong.feng@childrens.harvard.edu [Department of Medicine, Children' s Hospital Boston, Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 (United States); Xia, Qing, E-mail: xqing@hsc.pku.edu.cn [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China)

    2015-06-10

    As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. - Highlights: • BBR inhibited neurite outgrowth in early stages of neuronal development. • Lowered neuronal energy status was induced by BBR treatment. • Neuronal energy stress induced by BBR activated AMPK-related pathways. • BBR induced mitochondrial dysfunction and endoplasmic reticulum stress.

  6. Fenofibrate Intervention and Event Lowering in Diabetes (FIELD study: baseline characteristics and short-term effects of fenofibrate [ISRCTN64783481

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available Abstract Objective The Fenofibrate Intervention and Event Lowering in Diabetes (FIELD Study is examining the effects of long-term fibrate therapy on coronary heart disease (CHD event rates in patients with diabetes mellitus. This article describes the trial's run-in phase and patients' baseline characteristics. Research design and methods FIELD is a double-blind, placebo-controlled trial in 63 centres in 3 countries evaluating the effects of fenofibrate versus placebo on CHD morbidity and mortality in 9795 patients with type 2 diabetes mellitus. Patients were to have no indication for lipid-lowering therapy on randomization, but could start these or other drugs at any time after randomization. Follow-up in the study was to be for a median duration of not less than 5 years and until 500 major coronary events (fatal coronary heart disease plus nonfatal myocardial infarction had occurred. Results About 2100 patients (22% had some manifestation of cardiovascular disease (CVD at baseline and thus high risk status. Less than 25% of patients without CVD had a (UKPDS determined calculated 5-year CHD risk of 30, most were men, two-thirds were aged over 60 years, and substantial proportions had NCEP ATP III features of the metabolic syndrome independent of their diabetes, including low HDL (60%, high blood pressure measurement or treatment for hypertension (84%, high waist measurement (68%, and raised triglycerides (52%. After a 6-week run-in period before randomisation with all participants receiving 200 mg comicronized fenofibrate, there were declines in total and LDL cholesterol (10% and triglycerides (26% and an increase in HDL cholesterol (6.5%. Conclusion The study will show the effect of PPAR-alpha agonist action on CHD and other vascular outcomes in patients with type 2 diabetes including substantial numbers with low to moderate CVD risk but with the various components of the metabolic syndrome. The main results of the study will be reported in

  7. Fenofibrate suppressed proliferation and migration of human neuroblastoma cells via oxidative stress dependent of TXNIP upregulation

    Energy Technology Data Exchange (ETDEWEB)

    Su, Cunjin; Shi, Aiming; Cao, Guowen [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 (China); Tao, Tao [Department of Urology, Zhongda Hospital, Medical School of Southeast University, Nanjing, 210009 (China); Chen, Ruidong [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 (China); Hu, Zhanhong; Shen, Zhu; Tao, Hong; Cao, Bin [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 (China); Hu, Duanmin, E-mail: hudmsdfey@sina.com [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 (China); Bao, Junjie, E-mail: baojjsdfey@sina.com [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 (China)

    2015-05-15

    There are no appropriate drugs for metastatic neuroblastoma (NB), which is the most common extra-cranial solid tumor for childhood. Thioredoxin binding protein (TXNIP), the endogenous inhibitor of ROS elimination, has been identified as a tumor suppressor in various solid tumors. It reported that fenofibrate exerts anti-tumor effects in several human cancer cell lines. However, its detail mechanisms remain unclear. The present study assessed the effects of fenofibrate on NB cells and investigated TXNIP role in its anti-tumor mechanisms. We used MTT assay to detect cells proliferation, starch wound test to investigate cells migration, H{sub 2}DCF-DA to detect intracellular ROS, siRNA to interfere TXNIP and peroxisome proliferator-androgen receptor-alpha (PPAR-α) expression, western blot to determine protein levels, flow cytometry to analyze apoptosis. Fenofibrate suppressed proliferation and migration of NB cells, remarkably increased intracellular ROS, upregulated TXNIP expression, promoted cell apoptosis. Furthermore, inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. Our results indicated the anti-tumor role of fenofibrate on NB cells by exacerbating oxidative stress and inducing apoptosis was dependent on the upregulation of TXNIP. - Highlights: • We found that fenofibrate suppressed proliferation and migration of NB cells. • We found that fenofibrate remarkably increased intracellular ROS, upregulated TXNIP expression, and promoted cell apoptosis. • Inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. • Our results indicated the anti-tumor role of fenofibrate on NB cells was dependent on the upregulation of TXNIP.

  8. Fenofibrate suppressed proliferation and migration of human neuroblastoma cells via oxidative stress dependent of TXNIP upregulation

    International Nuclear Information System (INIS)

    Su, Cunjin; Shi, Aiming; Cao, Guowen; Tao, Tao; Chen, Ruidong; Hu, Zhanhong; Shen, Zhu; Tao, Hong; Cao, Bin; Hu, Duanmin; Bao, Junjie

    2015-01-01

    There are no appropriate drugs for metastatic neuroblastoma (NB), which is the most common extra-cranial solid tumor for childhood. Thioredoxin binding protein (TXNIP), the endogenous inhibitor of ROS elimination, has been identified as a tumor suppressor in various solid tumors. It reported that fenofibrate exerts anti-tumor effects in several human cancer cell lines. However, its detail mechanisms remain unclear. The present study assessed the effects of fenofibrate on NB cells and investigated TXNIP role in its anti-tumor mechanisms. We used MTT assay to detect cells proliferation, starch wound test to investigate cells migration, H 2 DCF-DA to detect intracellular ROS, siRNA to interfere TXNIP and peroxisome proliferator-androgen receptor-alpha (PPAR-α) expression, western blot to determine protein levels, flow cytometry to analyze apoptosis. Fenofibrate suppressed proliferation and migration of NB cells, remarkably increased intracellular ROS, upregulated TXNIP expression, promoted cell apoptosis. Furthermore, inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. Our results indicated the anti-tumor role of fenofibrate on NB cells by exacerbating oxidative stress and inducing apoptosis was dependent on the upregulation of TXNIP. - Highlights: • We found that fenofibrate suppressed proliferation and migration of NB cells. • We found that fenofibrate remarkably increased intracellular ROS, upregulated TXNIP expression, and promoted cell apoptosis. • Inhibition of TXNIP expression attenuated anti-tumor effects of fenofibrate, while inhibition of PPAR-α had no influences. • Our results indicated the anti-tumor role of fenofibrate on NB cells was dependent on the upregulation of TXNIP

  9. High Uric Acid Activates the ROS-AMPK Pathway, Impairs CD68 Expression and Inhibits OxLDL-Induced Foam-Cell Formation in a Human Monocytic Cell Line, THP-1

    Directory of Open Access Journals (Sweden)

    Chaohuan Luo

    2016-11-01

    Full Text Available Background/Aims: Hyperuricemia is part of the metabolic-syndrome cluster of abdominal obesity, impaired glucose tolerance, insulin resistance, dyslipidemia, and hypertension. Monocytes/macrophages are critical in the development of metabolic syndrome, including gout, obesity and atherosclerosis. However, how high uric acid (HUA exposure affects monocyte/macrophage function remains unclear. In this study, we investigated the molecular mechanism of HUA exposure in monocytes/macrophages and its impact on oxidized low-density lipoprotein (oxLDL-induced foam-cell formation in a human monocytic cell line, THP-1. Methods: We primed THP-1 cells with phorbol-12-myristate-13-acetate (PMA for differentiation, then exposed cells to HUA and detected the production of reactive oxygen species (ROS and analyzed the level of phospho-AMPKα. THP-1 cells were pre-incubated with Compound C, an AMPK inhibitor, or N-acetyl-L-cysteine (NAC, a ROS scavenger, or HUA before PMA, to assess CD68 expression and phospho-AMPKα level. PMA-primed THP-1 cells were pre-treated with oxLDL before Compound C and HUA treatment. Western blot analysis was used to examine the levels of phospho-AMPKα, CD68, ABCG1, ABCA1, cyclooxygenase-2 (COX-2 and NF-κB (p65. Flow cytometry was used to assess ROS production and CD68 expression in live cells. Oil-red O staining was used to observe oxLDL uptake in cells. Results: HUA treatment increased ROS production in PMA-primed THP-1 cells; NAC blocked HUA-induced oxidative stress. HUA treatment time-dependently increased phospho-AMPKα level in PMA-primed THP-1 cells. The HUA-induced oxidative stress increased phospho-AMPKα levels, which was blocked by NAC. HUA treatment impaired CD68 expression during cell differentiation by activating the AMPK pathway, which was reversed by Compound C treatment. Finally, HUA treatment inhibited oxLDL uptake in the formation of foam cells in THP-1 cells, which was blocked by Compound C treatment. HUA treatment

  10. AMPK maintains energy homeostasis and survival in cancer cells via regulating p38/PGC-1α-mediated mitochondrial biogenesis

    Science.gov (United States)

    Chaube, B; Malvi, P; Singh, S V; Mohammad, N; Viollet, B; Bhat, M K

    2015-01-01

    Cancer cells exhibit unique metabolic response and adaptation to the fluctuating microenvironment, yet molecular and biochemical events imprinting this phenomenon are unclear. Here, we show that metabolic homeostasis and adaptation to metabolic stress in cancer cells are primarily achieved by an integrated response exerted by the activation of AMPK. We provide evidence that AMPK-p38-PGC-1α axis, by regulating energy homeostasis, maintains survival in cancer cells under glucose-limiting conditions. Functioning as a molecular switch, AMPK promotes glycolysis by activating PFK2, and facilitates mitochondrial metabolism of non-glucose carbon sources thereby maintaining cellular ATP level. Interestingly, we noted that AMPK can promote oxidative metabolism via increasing mitochondrial biogenesis and OXPHOS capacity via regulating expression of PGC-1α through p38MAPK activation. Taken together, our study signifies the fundamental role of AMPK in controlling cellular bioenergetics and mitochondrial biogenesis in cancer cells. PMID:27551487

  11. How AMPK and PKA Interplay to Regulate Mitochondrial Function and Survival in Models of Ischemia and Diabetes

    Directory of Open Access Journals (Sweden)

    Jingdian Zhang

    2017-01-01

    Full Text Available Adenosine monophosphate-activated protein kinase (AMPK is a conserved, redox-activated master regulator of cell metabolism. In the presence of oxidative stress, AMPK promotes cytoprotection by enhancing the conservation of energy by suppressing protein translation and by stimulating autophagy. AMPK interplays with protein kinase A (PKA to regulate oxidative stress, mitochondrial function, and cell survival. AMPK and dual-specificity A-kinase anchoring protein 1 (D-AKAP1, a mitochondrial-directed scaffold of PKA, interact to regulate mitochondrial function and oxidative stress in cardiac and endothelial cells. Ischemia and diabetes, a chronic disease that increases the onset of cardiovascular diseases, suppress the cardioprotective effects of AMPK and PKA. Here, we review the molecular mechanisms by which AMPK and D-AKAP1/PKA interplay to regulate mitochondrial function, oxidative stress, and signaling pathways that prime endothelial cells, cardiac cells, and neurons for cytoprotection against oxidative stress. We discuss recent literature showing how temporal dynamics and localization of activated AMPK and PKA holoenzymes play a crucial role in governing cellular bioenergetics and cell survival in models of ischemia, cardiovascular diseases, and diabetes. Finally, we propose therapeutic strategies that tout localized PKA and AMPK signaling to reverse mitochondrial dysfunction, oxidative stress, and death of neurons and cardiac and endothelial cells during ischemia and diabetes.

  12. Cafeteria diet-induced insulin resistance is not associated with decreased insulin signaling or AMPK activity and is alleviated by physical training in rats

    DEFF Research Database (Denmark)

    Brandt, Nina; De Bock, Katrien; Richter, Erik

    2010-01-01

    Excess energy intake via a palatable low-fat diet (cafeteria diet) is known to induce obesity and glucose intolerance in rats. However, the molecular mechanisms behind this adaptation are not known, and it is also not known whether exercise training can reverse it. Male Wistar rats were assigned...... was counteracted by training. In the perfused hindlimb, insulin-stimulated glucose transport in red gastrocnemius muscle was completely abolished in CAF and rescued by exercise training. Apart from a tendency toward an approximately 20% reduction in both basal and insulin-stimulated Akt Ser(473) phosphorylation (P......) among the groups. In conclusion, surplus energy intake of a palatable but low-fat cafeteria diet resulted in obesity and insulin resistance that was rescued by exercise training. Interestingly, insulin resistance was not accompanied by major defects in the insulin-signaling cascade or in altered AMPK...

  13. Macropinocytosis is decreased in diabetic mouse macrophages and is regulated by AMPK.

    Science.gov (United States)

    Guest, Christopher B; Chakour, Kenneth S; Freund, Gregory G

    2008-07-30

    Macrophages (MPhis) utilize macropinocytosis to integrate immune and metabolic signals in order to initiate an effective immune response. Diabetes is characterized by metabolic abnormalities and altered immune function. Here we examine the influence of diabetes on macropinocytosis in primary mouse macrophages and in an in vitro diabetes model. The data demonstrate that peritoneal MPhis from diabetic (db/db) mice had reduced macropinocytosis when compared to MPhis from non-diabetic (db/+) mice. Additionally, MPhis cultured in hyperglycemic conditions were less adept at macropinocytosis than those cultured in low glucose. Notably, AMP-activated protein kinase (AMPK) activity was decreased in MPhis cultured in hyperglycemic conditions. Activation of AMPK with leptin or 5-aminoimidazole-4-carboxamide-1-beta-riboside (AICAR) increased macropinocytosis and inhibition of AMPK with compound C decreased macropinocytosis. Taken together, these findings indicate that MPhis from diabetic mice have decreased macropinocytosis. This decrease appears dependent on reduced AMPK activity. These results demonstrate a previously unrealized role for AMPK in MPhis and suggest that increasing AMPK activity in diabetic MPhis could improve innate immunity and decrease susceptibility to infection.

  14. A Rare Cause of Acute Renal Failure: Fenofibrate-Induced Rhabdomyolysis

    Directory of Open Access Journals (Sweden)

    Ferhat Icme

    2013-08-01

    Full Text Available Fibrates are derivative of fibric acid and broad spectrum drugs which are commonly used in the treatment of dyslipidemia and hypertriglyceridemia. Side effects are often related with striated muscles, kidney and liver. Rhabdomyolysis developing with striated muscle destruction is potentially the most lethal of these side effects. Although several case reports of rhabdomyolysis have been reported due to the combination of statin and fenofibrate, fenofibrate alone rarely causes rhabdomyolysis. The purposes of this paper are to present a patient whom we diagnosed with acute renal injury due to use of fenofibrate in order to emphasize the importance of questioning drugs which have been used, and to review management of rhabdomyolysis due to fenofibrate use. [Cukurova Med J 2013; 38(4.000: 800-804

  15. Glucocorticoid excess induces accumulation of cardiac glycogen and triglyceride: suggested role for AMPK.

    Science.gov (United States)

    Puthanveetil, Prasanth; Rodrigues, Brian

    2013-01-01

    Glucocorticoids include steroid hormones released from the adrenal cortex or synthetic analogues developed for various inflammatory and immune disorders. GCs are known to play an important role in maintaining the body's metabolic balance, but their irregular activity has been associated with complications like Cushing's syndrome, insulin resistance, and heart disease. Conventional GC action is through their nuclear receptor activation, but specific and non-specific membrane bound receptor mediated non-genomic actions have also been reported. GCs increase AMPK phosphorylation at Thr172, in addition to augmenting AMPK protein and gene expressions. AMPK is insulin mimetic in many of its actions like glucose uptake and inhibition of lipolysis, and these properties of AMPK are made used in conditions like insulin resistance and diabetes. Nevertheless, if AMPK is activated by GC in the absence of diabetes or decreased insulin signaling, accumulation of substrates in the form of glycogen and triglycerides could precipitate cardiac abnormalities. Glycogen storage can lead to many disorders like hypertrophy, conduction system disease and Wolff Parkinson White syndrome. TG accumulation is associated with generation of free radicals, ceramide formation, mitochondrial dysfunction and cardiac cell death. In this review, we outline the cardiometabolic changes associated with GC, especially related to augmentation in AMPK, and link these changes to cardiac dysfunction.

  16. Shizukaol D isolated from Chloranthus japonicas inhibits AMPK-dependent lipid content in hepatic cells by inducing mitochondrial dysfunction.

    Directory of Open Access Journals (Sweden)

    Rongkuan Hu

    Full Text Available This study is the first to demonstrate that shizukaol D, a natural compound isolated from Chloranthusjaponicus, can activate AMP- activated protein kinase (AMPK, a key sensor and regulator of intracellular energy metabolism, leading to a decrease in triglyceride and cholesterol levels in HepG2 cells. Furthermore, we found that shizukaol D induces mitochondrial dysfunction by depolarizing the mitochondrial membrane and suppressing energy production, which may result in AMPK activation. Our results provide a possible link between mitochondrial dysfunction and AMPK activation and suggest that shizukaol D might be used to treat metabolic syndrome.

  17. Fenofibrate Therapy Restores Antioxidant Protection and Improves Myocardial Insulin Resistance in a Rat Model of Metabolic Syndrome and Myocardial Ischemia: The Role of Angiotensin II

    Directory of Open Access Journals (Sweden)

    Luz Ibarra-Lara

    2016-12-01

    Full Text Available Renin-angiotensin system (RAS activation promotes oxidative stress which increases the risk of cardiac dysfunction in metabolic syndrome (MetS and favors local insulin resistance. Fibrates regulate RAS improving MetS, type-2 diabetes and cardiovascular diseases. We studied the effect of fenofibrate treatment on the myocardic signaling pathway of Angiotensin II (Ang II/Angiotensin II type 1 receptor (AT1 and its relationship with oxidative stress and myocardial insulin resistance in MetS rats under heart ischemia. Control and MetS rats were assigned to the following groups: (a sham; (b vehicle-treated myocardial infarction (MI (MI-V; and (c fenofibrate-treated myocardial infarction (MI-F. Treatment with fenofibrate significantly reduced triglycerides, non-high density lipoprotein cholesterol (non-HDL-C, insulin levels and insulin resistance index (HOMA-IR in MetS animals. MetS and MI increased Ang II concentration and AT1 expression, favored myocardial oxidative stress (high levels of malondialdehyde, overexpression of nicotinamide adenine dinucleotide phosphate (NADPH oxidase 4 (NOX4, decreased total antioxidant capacity and diminished expression of superoxide dismutase (SOD1, SOD2 and catalase and inhibited expression of the insulin signaling cascade: phosphatidylinositol 3-kinase (PI3K/protein kinase B (PkB, also known as Akt/Glut-4/endothelial nitric oxide synthase (eNOS. In conclusion, fenofibrate treatment favors an antioxidant environment as a consequence of a reduction of the Ang II/AT1/NOX4 signaling pathway, reestablishing the cardiac insulin signaling pathway. This might optimize cardiac metabolism and improve the vasodilator function during myocardial ischemia.

  18. Effects of Fenofibrate on Adiponectin Expression in Retinas of Streptozotocin-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Ying-Jung Hsu

    2014-01-01

    Full Text Available Adiponectin has been associated with increased risks of microvascular complications in diabetes; however, its role in the development of diabetic retinopathy (DR is unknown. Fenofibrate is a lipid-lowering agent that has been shown to be capable of preventing DR progression. We investigated the expression of adiponectin and its receptors in DR and evaluated the effects of fenofibrate on their expression. The mRNA and protein levels of adiponectin and its receptors were elevated in retinas of streptozotocin-induced diabetic rats and were suppressed following fenofibrate treatment. Immunofluorescence staining demonstrated that adiponectin and adipoR1 were expressed in cells located within blood vessels, the retinal ganglion, and the inner nuclear layer. AdipoR1 was strongly expressed whereas adipoR2 was only weekly expressed in vascular endothelial cells. The in vitro experiments showed that adiponectin expression was induced by high glucose concentrations in RGC-5 and RAW264.7 cells and was suppressed following fenofibrate treatment. AdipoR1 and adipoR2 levels in RGC-5 cells were elevated in high glucose concentrations and suppressed by fenofibrate. Our results demonstrated that adiponectin may be a proinflammatory mediator in diabetic retinas and fenofibrate appears to modulate the expression of adiponectin and its receptors in diabetic retinas, effectively reducing DR progression.

  19. Contributions of AMPK and p53 dependent signaling to radiation response in the presence of metformin.

    Science.gov (United States)

    Muaddi, Hala; Chowdhury, Sanjana; Vellanki, Ravi; Zamiara, Paul; Koritzinsky, Marianne

    2013-09-01

    Metformin is commonly prescribed to treat type 2 diabetes, and has additional potential as a cancer prophylactic and therapeutic. Metformin activates AMPK that in turn can launch a p53-dependent metabolic checkpoint. Possible interactions between metformin and radiation are poorly understood. Since radiation-induced signaling also involves AMPK and p53, we investigated their importance in mediating responses to metformin and radiation. A549 cells, HCT116 cells wildtype or knockout for p53 or MEFs wildtype or double knockout for AMPKα1 and α2 were irradiated in the presence or absence of metformin. The impact of metformin on oxygen consumption and proliferation rates was determined, as well as clonogenic radiation survival. Metformin resulted in moderate radiation protection in all cell lines, irrespective of AMPK and p53. Loss of AMPK sensitized cells to the anti-proliferative effects of metformin, while loss of p53 promoted both the growth inhibitory and toxic effects of metformin. Consequently, overall cell death after radiation was similar with and without metformin irrespective of AMPK or p53 genotype. The anti-proliferative activity of metformin may confer benefit in combination with radiotherapy, and this benefit is intensified upon loss of AMPK or p53 signaling. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  20. Elimination of cancer stem cells and reactivation of latent HIV-1 via AMPK activation: Common mechanism of action linking inhibition of tumorigenesis and the potential eradication of HIV-1.

    Science.gov (United States)

    Finley, Jahahreeh

    2017-07-01

    that activation of AMPK, a master regulator of cellular metabolism that plays a critical role in T cell activation and differentiation of ESCs and ASCs, will lead to both T cell activation-induced latent HIV-1 reactivation, facilitating virus destruction, as well as "activation", differentiation, and/or apoptosis of CSCs, thus inhibiting tumorigenesis. We also propose the novel observation that compounds that have been shown to both facilitate latent HIV-1 reactivation and promote CSC differentiation/apoptosis (e.g. bryostatin-1, JQ1, metformin, butyrate, etc.) likely do so through a common mechanism of AMPK activation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. [Fibrates therapy: Rational use fenofibrate 2016. Executive summary].

    Science.gov (United States)

    Brea, Angel; Millán, Jesús; Ascaso, Juan F; Blasco, Mariano; Díaz, Angel; González-Santos, Pedro; Hernández-Mijares, Antonio; Mantilla, Teresa; Pedro-Botet, Juan C; Pintó, Xavier

    To control lipid factors risk, beyond proper management of LDL cholesterol according to individual risk, detection and treatment of atherogenic dyslipidemia and abnormal levels of triglycerides or HDL cholesterol it should be considered for address a global cardiovascular protection, both in primary and secondary prevention. In this sense, these recommendations collect data on efficacy and safety about the combination statin with fibrates, often necessary for total control of dyslipidemia, particularly in patients with metabolic disorders such as diabetes mellitus, metabolic syndrome or visceral obesity. Reference to control and monitoring of treatment is also done, as well as benefits of fenofibrate not linked directly to their lipid-lowering effect. Copyright © 2016 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Spray drying of fenofibrate loaded nanostructured lipid carriers

    DEFF Research Database (Denmark)

    Xia, Dengning; Shrestha, Neha; van de Streek, Jacco

    2016-01-01

    The conversion of aqueous dispersion of nanostructured lipid carriers (NLCs) into dry powder by spray drying could be a useful approach to render NLCs with better physical chemical stability than the aqueous dispersion. In this study, aqueous NLC dispersion containing fenofibrate was converted...... into dry, easily reconstitutable powder using spray drying. A central composite face centered design (CCFD) was used to investigate the influence of the ratio of lipid to protectant (mannitol and trehalose) and crystallinity of spray-dried powder on the particle size, yield and residual moisture content...... of the dried powder. A linear relationship (R2 = 0.9915) was established between the crystalline content of the spray-dried powders against the ratio of mannitol to trehalose from 3:7 to 10:0 (w/w). Spray drying of NLC aqueous dispersion using a mannitol and trehalose mixture resulted in an increase...

  3. Pomegranate extract decreases oxidative stress and alleviates mitochondrial impairment by activating AMPK-Nrf2 in hypothalamic paraventricular nucleus of spontaneously hypertensive rats.

    Science.gov (United States)

    Sun, Wenyan; Yan, Chunhong; Frost, Bess; Wang, Xin; Hou, Chen; Zeng, Mengqi; Gao, Hongli; Kang, Yuming; Liu, Jiankang

    2016-10-07

    High blood pressure, or "hypertension," is associated with high levels of oxidative stress in the paraventricular nucleus of the hypothalamus. While pomegranate extract is a known antioxidant that is thought to have antihypertensive effects, the mechanism whereby pomegranate extract lowers blood pressure and the tissue that mediates its antihypertensive effects are currently unknown. We have used a spontaneously hypertensive rat model to investigate the antihypertensive properties of pomegranate extract. We found that chronic treatment of hypertensive rats with pomegranate extract significantly reduced blood pressure and cardiac hypertrophy. Furthermore, pomegranate extract reduced oxidative stress, increased the antioxidant defense system, and decreased inflammation in the paraventricular nucleus of hypertensive rats. We determined that pomegranate extract reduced mitochondrial superoxide anion levels and increased mitochondrial function in the paraventricular nucleus of hypertensive rats by promoting mitochondrial biogenesis and improving mitochondrial dynamics and clearance. We went on to identify the AMPK-nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) pathway as a mechanism whereby pomegranate extract reduces oxidative stress in the paraventricular nucleus to relieve hypertension. Our findings demonstrate that pomegranate extract alleviates hypertension by reducing oxidative stress and improving mitochondrial function in the paraventricular nucleus, and reveal multiple novel targets for therapeutic treatment of hypertension.

  4. Riluzole increases the rate of glucose transport in L6 myotubes and NSC-34 motor neuron-like cells via AMPK pathway activation.

    Science.gov (United States)

    Daniel, Bareket; Green, Omer; Viskind, Olga; Gruzman, Arie

    2013-09-01

    Riluzole is the only approved ALS drug. Riluzole influences several cellular pathways, but its exact mechanism of action remains unclear. Our goal was to study the drug's influence on the glucose transport rate in two ALS relevant cell types, neurons and myotubes. Stably transfected wild-type or mutant G93A human SOD1 NSC-34 motor neuron-like cells and rat L6 myotubes were exposed to riluzole. The rate of glucose uptake, translocation of glucose transporters to the cell's plasma membrane and the main glucose transport regulatory proteins' phosphorylation levels were measured. We found that riluzole increases the glucose transport rate and up-regulates the translocation of glucose transporters to plasma membrane in both types of cells. Riluzole leads to AMPK phosphorylation and to the phosphorylation of its downstream target, AS-160. In conclusion, increasing the glucose transport rate in ALS affected cells might be one of the mechanisms of riluzole's therapeutic effect. These findings can be used to rationally design and synthesize novel anti-ALS drugs that modulate glucose transport in neurons and skeletal muscles.

  5. Two weeks of metformin treatment enhances mitochondrial respiration in skeletal muscle of AMPK kinase dead but not wild type mice.

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    Jonas M Kristensen

    Full Text Available Metformin is used as an anti-diabetic drug. Metformin ameliorates insulin resistance by improving insulin sensitivity in liver and skeletal muscle. Reduced mitochondrial content has been reported in type 2 diabetic muscles and it may contribute to decreased insulin sensitivity characteristic for diabetic muscles. The molecular mechanism behind the effect of metformin is not fully clarified but inhibition of complex I in the mitochondria and also activation of the 5'AMP activated protein kinase (AMPK has been reported in muscle. Furthermore, both AMPK activation and metformin treatment have been associated with stimulation of mitochondrial function and biogenesis. However, a causal relationship in skeletal muscle has not been investigated. We hypothesized that potential effects of in vivo metformin treatment on mitochondrial function and protein expressions in skeletal muscle are dependent upon AMPK signaling. We investigated this by two weeks of oral metformin treatment of muscle specific kinase dead α(2 (KD AMPK mice and wild type (WT littermates. We measured mitochondrial respiration and protein activity and expressions of key enzymes involved in mitochondrial carbohydrate and fat metabolism and oxidative phosphorylation. Mitochondrial respiration, HAD and CS activity, PDH and complex I-V and cytochrome c protein expression were all reduced in AMPK KD compared to WT tibialis anterior muscles. Surprisingly, metformin treatment only enhanced respiration in AMPK KD mice and thereby rescued the respiration defect compared to the WT mice. Metformin did not influence protein activities or expressions in either WT or AMPK KD mice.We conclude that two weeks of in vivo metformin treatment enhances mitochondrial respiration in the mitochondrial deficient AMPK KD but not WT mice. The improvement seems to be unrelated to AMPK, and does not involve changes in key mitochondrial proteins.

  6. Two weeks of metformin treatment enhances mitochondrial respiration in skeletal muscle of AMPK kinase dead but not wild type mice.

    Science.gov (United States)

    Kristensen, Jonas M; Larsen, Steen; Helge, Jørn W; Dela, Flemming; Wojtaszewski, Jørgen F P

    2013-01-01

    Metformin is used as an anti-diabetic drug. Metformin ameliorates insulin resistance by improving insulin sensitivity in liver and skeletal muscle. Reduced mitochondrial content has been reported in type 2 diabetic muscles and it may contribute to decreased insulin sensitivity characteristic for diabetic muscles. The molecular mechanism behind the effect of metformin is not fully clarified but inhibition of complex I in the mitochondria and also activation of the 5'AMP activated protein kinase (AMPK) has been reported in muscle. Furthermore, both AMPK activation and metformin treatment have been associated with stimulation of mitochondrial function and biogenesis. However, a causal relationship in skeletal muscle has not been investigated. We hypothesized that potential effects of in vivo metformin treatment on mitochondrial function and protein expressions in skeletal muscle are dependent upon AMPK signaling. We investigated this by two weeks of oral metformin treatment of muscle specific kinase dead α(2) (KD) AMPK mice and wild type (WT) littermates. We measured mitochondrial respiration and protein activity and expressions of key enzymes involved in mitochondrial carbohydrate and fat metabolism and oxidative phosphorylation. Mitochondrial respiration, HAD and CS activity, PDH and complex I-V and cytochrome c protein expression were all reduced in AMPK KD compared to WT tibialis anterior muscles. Surprisingly, metformin treatment only enhanced respiration in AMPK KD mice and thereby rescued the respiration defect compared to the WT mice. Metformin did not influence protein activities or expressions in either WT or AMPK KD mice.We conclude that two weeks of in vivo metformin treatment enhances mitochondrial respiration in the mitochondrial deficient AMPK KD but not WT mice. The improvement seems to be unrelated to AMPK, and does not involve changes in key mitochondrial proteins.

  7. Molecular Mechanisms of Fenofibrate-Induced Metabolic Catastrophe and Glioblastoma Cell Death

    Science.gov (United States)

    Wilk, Anna; Wyczechowska, Dorota; Zapata, Adriana; Dean, Matthew; Mullinax, Jennifer; Marrero, Luis; Parsons, Christopher; Peruzzi, Francesca; Culicchia, Frank; Ochoa, Augusto; Grabacka, Maja

    2014-01-01

    Fenofibrate (FF) is a common lipid-lowering drug and a potent agonist of the peroxisome proliferator-activated receptor alpha (PPARα). FF and several other agonists of PPARα have interesting anticancer properties, and our recent studies demonstrate that FF is very effective against tumor cells of neuroectodermal origin. In spite of these promising anticancer effects, the molecular mechanism(s) of FF-induced tumor cell toxicity remains to be elucidated. Here we report a novel PPARα-independent mechanism explaining FF's cytotoxicity in vitro and in an intracranial mouse model of glioblastoma. The mechanism involves accumulation of FF in the mitochondrial fraction, followed by immediate impairment of mitochondrial respiration at the level of complex I of the electron transport chain. This mitochondrial action sensitizes tested glioblastoma cells to the PPARα-dependent metabolic switch from glycolysis to fatty acid β-oxidation. As a consequence, prolonged exposure to FF depletes intracellular ATP, activates the AMP-activated protein kinase–mammalian target of rapamycin–autophagy pathway, and results in extensive tumor cell death. Interestingly, autophagy activators attenuate and autophagy inhibitors enhance FF-induced glioblastoma cytotoxicity. Our results explain the molecular basis of FF-induced glioblastoma cytotoxicity and reveal a new supplemental therapeutic approach in which intracranial infusion of FF could selectively trigger metabolic catastrophe in glioblastoma cells. PMID:25332241

  8. [Metformin and AMPK: an old drug and a new enzyme in the context of metabolic syndrome].

    Science.gov (United States)

    Santomauro Júnior, Augusto Cézar; Ugolini, Michelle Remião; Santomauro, Ana Teresa; Souto, Ricardo Peres do

    2008-02-01

    Metformin is one of the most commonly prescribed oral antidiabetic agents worldwide. However, its mechanism of action remains unknown. The Diabetes Prevention Program Research Group studies have shown that metformin administration and lifestyle-intervention (diet and exercise) reduce the incidence of Diabetes Mellitus type 2 (DM2). A possible biochemical connection between both therapies may be the AMP-activated protein kinase (AMPK). This enzyme was originally described as a sensor of cellular energy status, being activated in exercise. On the other hand, several experimental evidences indicate that AMPK may be an important target of metformin action. This paper discusses various ways for AMPK regulation, suggesting a possible mechanism for its activation by metformin that involves the production of reactive nitrogen species. AMPK activation determines a wide variety of physiological effects, including enhanced glucose uptake by skeletal muscle and enhanced lipid catabolism. Thus, it may be a key player not only in the prevention and treatment of DM2, but also in the development of new treatments for obesity and the metabolic syndrome. The finding of AMPK activation by metformin draws attention to this enzyme as an important pharmacological target.

  9. Kolliphor surfactants affect solubilization and bioavailability of fenofibrate. Studies of in vitro digestion and absorption in rats

    DEFF Research Database (Denmark)

    Berthelsen, Ragna; Holm, Rene; Jacobsen, Jette

    2015-01-01

    formulations only comprised an aqueous micellar solution of the model drug (fenofibrate) in varying concentrations (2–25% (w/v)) of the three tested surfactants. Increased concentrations of Kolliphor ELP and EL led to increased fenofibrate AUC0–24h values. For the Kolliphor RH40 formulations, an apparent...... fenofibrate absorption optimum was seen at 15% (w/v) surfactant, displaying both the highest AUC0–24h and Cmax. The reduced absorption of fenofibrate from the formulation containing the highest level of surfactant (25% w/v) was thought to be caused by some degree of trapping within Kolliphor RH40 micelles....... In vitro, Kolliphor ELP and EL were found to be more prone to digestion than Kolliphor RH40, though not affecting the in vivo results. The highest fenofibrate bioavailability was attained from formulations with high Kolliphor ELP/EL levels (25% (w/v)), indicating that these surfactants are the better...

  10. Effect of Curcumin on Phosphorylation of AMPK and ACC in C2C12 Skeletal Muscle Cells

    Directory of Open Access Journals (Sweden)

    F Ghanbarzadeh

    2013-10-01

    Full Text Available Introduction: AMP activated protein kinase (AMPK as key regulators of cell metabolism, plays a major role in the activation of catabolic pathways, such as glucose transport and fatty acid oxidation. Thus, activation of this pathway can be used in the treatment of diabetes and metabolic syndrome. Many studied proposed the effectiveness of the polyphenols present in rhizomes of turmeric (curcumin on diabetes and its related complications. Therefore, this study investigated the effects of curcumin as an activator of AMPK pathway in C2C12 muscle cells. Methods: This study was done on C2C12 skeletal muscle cell line. The cells were classified into two distinct groups: first group was treated with 40µM curcumin and the second one with 0.1% DMSO as a negative control. The phosphorylated (AMPK and phosphorylated acetyl COA carboxylase (ACC were evaluated and compared by Western blotting technique. Results: intracellular phosphorylated AMPK protein content in Curcumin-treated group was 132.6% and ACC protein phosphorylated was 366.47%. Conclusion: This study showed that the levels of phosphorylated AMPK and ACC protein in cells treated with curcumin are higher than the negative control. Thus curcumin can be regarded as an activator of AMPK activity in these cells and can assist as a potential target for making anti diabetic medecine that has a synergistic activity with insulin.

  11. Lifespan extension induced by AMPK and calcineurin is mediated by CRTC-1 and CREB.

    Science.gov (United States)

    Mair, William; Morantte, Ianessa; Rodrigues, Ana P C; Manning, Gerard; Montminy, Marc; Shaw, Reuben J; Dillin, Andrew

    2011-02-17

    Activating AMPK or inactivating calcineurin slows ageing in Caenorhabditis elegans and both have been implicated as therapeutic targets for age-related pathology in mammals. However, the direct targets that mediate their effects on longevity remain unclear. In mammals, CREB-regulated transcriptional coactivators (CRTCs) are a family of cofactors involved in diverse physiological processes including energy homeostasis, cancer and endoplasmic reticulum stress. Here we show that both AMPK and calcineurin modulate longevity exclusively through post-translational modification of CRTC-1, the sole C. elegans CRTC. We demonstrate that CRTC-1 is a direct AMPK target, and interacts with the CREB homologue-1 (CRH-1) transcription factor in vivo. The pro-longevity effects of activating AMPK or deactivating calcineurin decrease CRTC-1 and CRH-1 activity and induce transcriptional responses similar to those of CRH-1 null worms. Downregulation of crtc-1 increases lifespan in a crh-1-dependent manner and directly reducing crh-1 expression increases longevity, substantiating a role for CRTCs and CREB in ageing. Together, these findings indicate a novel role for CRTCs and CREB in determining lifespan downstream of AMPK and calcineurin, and illustrate the molecular mechanisms by which an evolutionarily conserved pathway responds to low energy to increase longevity.

  12. AMPK in the central nervous system: physiological roles and pathological implications

    Directory of Open Access Journals (Sweden)

    Rosso P

    2016-01-01

    Full Text Available Pamela Rosso,1,2,* Marco Fioramonti,3,* Anna Fracassi,2 Martina Marangoni,4 Valentina Taglietti,5 Silvia Siteni,2,6 Marco Segatto5 1Institute of Cell Biology and Neurobiology, National Research Council (CNR, 2Department of Sciences, University of Rome “Roma Tre”, 3Laboratory of Translational Oncology, University Campus Bio-Medico of Rome, 4Medical Genetics Unit, University Hospital of Rome “Tor Vergata”, Rome, 5Department of Biosciences, University of Milan, Milan, 6Department of Experimental Oncology, Regina Elena National Cancer Institute, Rome, Italy *These authors contributed equally to this work Abstract: 5′ AMP-activated protein kinase (AMPK is considered the master metabolic regulator in all eukaryotes, as it maintains cellular energy homeostasis in a variety of tissues, including the brain. In humans, alterations in AMPK activity can lead to a wide spectrum of metabolic disorders. The relevance of this protein kinase in the pathogenesis of diabetes and metabolic syndrome is now well established. On the contrary, correlations between AMPK and brain physiopathology are still poorly characterized. The aim of this review is to summarize and discuss the current knowledge about the prospective involvement of AMPK in the onset and the progression of different neurological diseases. Keywords: AMPK, brain, neurodegeneration, stroke, tumor, autophagy

  13. AMPK Agonist AICAR Improves Cognition and Motor Coordination in Young and Aged Mice

    Science.gov (United States)

    Kobilo, Tali; Guerrieri, Davide; Zhang, Yongqing; Collica, Sarah C.; Becker, Kevin G.; van Praag, Henriette

    2014-01-01

    Normal aging can result in a decline of memory and muscle function. Exercise may prevent or delay these changes. However, aging-associated frailty can preclude physical activity. In young sedentary animals, pharmacological activation of AMP-activated protein kinase (AMPK), a transcriptional regulator important for muscle physiology, enhanced…

  14. Effect of birth weight and 12 weeks of exercise training on exercise-induced AMPK signaling in human skeletal muscle

    DEFF Research Database (Denmark)

    Mortensen, Brynjulf; Hingst, Janne Rasmuss; Frederiksen, Nicklas

    2013-01-01

    Subjects with a low birth weight (LBW) display increased risk of developing type 2 diabetes (T2D). We hypothesized that this is associated with defects in muscle adaptations following acute and regular physical activity, evident by impairments in the exercise-induced activation of AMPK signaling....... the need for AMPK to control energy turnover during exercise. Thus, the remaining ¿3-associated AMPK activation by acute exercise after exercise training might be sufficient to maintain cellular energy balance........ We investigated 21 LBW and 21 normal birth weight (NBW) subjects during 1 hour of acute exercise performed at the same relative workload before and after 12 weeks of exercise training. Multiple skeletal muscle biopsies were obtained before and after exercise. Protein levels and phosphorylation status...... were determined by Western blotting. AMPK activities were measured using activity assays. Protein levels of AMPK isoforms a1 and ¿1 were significantly increased while ¿3 levels decreased with training independent of group. The LBW group had higher exercise-induced AMPK Thr(172) phosphorylation before...

  15. Reactivation of latently infected HIV-1 viral reservoirs and correction of aberrant alternative splicing in the LMNA gene via AMPK activation: Common mechanism of action linking HIV-1 latency and Hutchinson-Gilford progeria syndrome.

    Science.gov (United States)

    Finley, Jahahreeh

    2015-09-01

    AMPK, a master regulator of cellular metabolism which has been shown to activate PKC-theta (θ) and is essential for T cell activation, may modulate the splicing activities of SRp55 as well as enhance a p32-mediated inhibition of ASF/SF2-induced alternative splicing, potentially correcting aberrant alternative splicing in the LMNA gene and reactivating latent viral HIV-1 reservoirs. Moreover, similar epigenetic modifications and cell cycle regulators also characterize the analogous stages of premature senescence in progeroid cells and latency in HIV-1 infected T cells. AMPK-activating compounds including metformin and resveratrol may thus embody a novel treatment paradigm linking the pathophysiology of HGPS with that of HIV-1 latency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. AMPK regulates circadian rhythms in a tissue- and isoform-specific manner.

    Directory of Open Access Journals (Sweden)

    Jee-Hyun Um

    2011-03-01

    Full Text Available AMP protein kinase (AMPK plays an important role in food intake and energy metabolism, which are synchronized to the light-dark cycle. In vitro, AMPK affects the circadian rhythm by regulating at least two clock components, CKIα and CRY1, via direct phosphorylation. However, it is not known whether the catalytic activity of AMPK actually regulates circadian rhythm in vivo.THE CATALYTIC SUBUNIT OF AMPK HAS TWO ISOFORMS: α1 and α2. We investigate the circadian rhythm of behavior, physiology and gene expression in AMPKα1-/- and AMPKα2-/- mice. We found that both α1-/- and α2-/- mice are able to maintain a circadian rhythm of activity in dark-dark (DD cycle, but α1-/- mice have a shorter circadian period whereas α2-/- mice showed a tendency toward a slightly longer circadian period. Furthermore, the circadian rhythm of body temperature was dampened in α1-/- mice, but not in α2-/- mice. The circadian pattern of core clock gene expression was severely disrupted in fat in α1-/- mice, but it was severely disrupted in the heart and skeletal muscle of α2-/- mice. Interestingly, other genes that showed circadian pattern of expression were dysreguated in both α1-/- and α2-/- mice. The circadian rhythm of nicotinamide phosphoryl-transferase (NAMPT activity, which converts nicotinamide (NAM to NAD+, is an important regulator of the circadian clock. We found that the NAMPT rhythm was absent in AMPK-deficient tissues and cells.This study demonstrates that the catalytic activity of AMPK regulates circadian rhythm of behavior, energy metabolism and gene expression in isoform- and tissue-specific manners.

  17. Influences of different dietary energy level on sheep testicular development associated with AMPK/ULK1/autophagy pathway.

    Science.gov (United States)

    Pang, Jing; Li, Fengzhe; Feng, Xu; Yang, Hua; Han, Le; Fan, Yixuan; Nie, Haitao; Wang, Zhen; Wang, Feng; Zhang, Yanli

    2018-03-01

    Energy balance is an important feature for spermatozoa production in the testis. The 5'-AMP-activated protein kinase (AMPK) is a sensor of cell energy, has been implicated as a mediator between gonadal function and energy balance. Herein, we intended to determine the physiological effects of AMPK on testicular development in feed energy restricted and compensated pre-pubertal rams. Lambs had restricted feeding for 2 months and then provided compensatory feeding for another 3 months. Feed levels were 100%(control), 15% and 30% of energy restriction (ER) diets, respectively. The results showed that lambs fed the 30% ER diet had significantly lower testicular weight (P energy requirement after restriction. Taken together, dietary energy levels influence testicular development through autophagy and apoptosis interplay mediated by AMPK-ULK1 signal pathway, which also indicates the important role of the actions of AMPK in the testis homeostasis. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. AMPK in skeletal muscle function and metabolism

    DEFF Research Database (Denmark)

    Kjøbsted, Rasmus; Hingst, Janne Rasmuss; Fentz, Joachim

    2018-01-01

    highly changeable energy turnover. Due to the drastic changes in energy demand that occur between the resting and exercising state, skeletal muscle is one such tissue. Here, we review the complex regulation of AMPK in skeletal muscle and its consequences on metabolism (e.g., substrate uptake, oxidation......, and storage as well as mitochondrial function of skeletal muscle fibers). We focus on the role of AMPK in skeletal muscle during exercise and in exercise recovery. We also address adaptations to exercise training, including skeletal muscle plasticity, highlighting novel concepts and future perspectives...

  19. AMPK and the biochemistry of exercise: implications for human health and disease

    DEFF Research Database (Denmark)

    Richter, Erik; Ruderman, Neil B.

    2009-01-01

    AMPK (AMP-activated protein kinase) is a phylogenetically conserved fuel-sensing enzyme that is present in all mammalian cells. During exercise, it is activated in skeletal muscle in humans, and at least in rodents, also in adipose tissue, liver and perhaps other organs by events that increase th...

  20. Interdependence of AMPK and SIRT1 for metabolic adaptation to fasting and exercise in skeletal muscle

    DEFF Research Database (Denmark)

    Cantó, Carles; Jiang, Lake Q; Deshmukh, Atul S

    2010-01-01

    During fasting and after exercise, skeletal muscle efficiently switches from carbohydrate to lipid as the main energy source to preserve glycogen stores and blood glucose levels for glucose-dependent tissues. Skeletal muscle cells sense this limitation in glucose availability and transform...... this information into transcriptional and metabolic adaptations. Here we demonstrate that AMPK acts as the prime initial sensor that translates this information into SIRT1-dependent deacetylation of the transcriptional regulators PGC-1alpha and FOXO1, culminating in the transcriptional modulation of mitochondrial...... and lipid utilization genes. Deficient AMPK activity compromises SIRT1-dependent responses to exercise and fasting, resulting in impaired PGC-1alpha deacetylation and blunted induction of mitochondrial gene expression. Thus, we conclude that AMPK acts as the primordial trigger for fasting- and exercise...

  1. Enhancement of the dissolution rate and bioavailability of fenofibrate by a melt-adsorption method using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Cha KH

    2012-10-01

    Full Text Available Kwang-Ho Cha,1,3 Kyung-Jin Cho,3 Min-Soo Kim,4 Jeong-Soo Kim,3 Hee Jun Park,1,3 Junsung Park,1,3 Wonkyung Cho,1,3 Jeong-Sook Park,3 Sung-Joo Hwang1,21Yonsei Institute of Pharmaceutical Sciences, 2College of Pharmacy, Yonsei University, Incheon, Republic of Korea; 3College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea; 4Department of Pharmaceutical Engineering, Inje University, Gimhae, Republic of KoreaBackground: The aim of this study was to enhance the bioavailability of fenofibrate, a poorly water-soluble drug, using a melt-adsorption method with supercritical CO2.Methods: Fenofibrate was loaded onto Neusilin® UFL2 at different weight ratios of fenofibrate to Neusilin UFL2 by melt-adsorption using supercritical CO2. For comparison, fenofibrate-loaded Neusilin UFL2 was prepared by solvent evaporation and hot melt-adsorption methods. The fenofibrate formulations prepared were characterized by differential scanning calorimetry, powder x-ray diffractometry, specific surface area, pore size distribution, scanning electron microscopy, and energy-dispersive x-ray spectrometry. In vitro dissolution and in vivo bioavailability were also investigated.Results: Fenofibrate was distributed into the pores of Neusilin UFL2 and showed reduced crystal formation following adsorption. Supercritical CO2 facilitated the introduction of fenofibrate into the pores of Neusilin UFL2. Compared with raw fenofibrate, fenofibrate from the prepared powders showed a significantly increased dissolution rate and better bioavailability. In particular, the area under the drug concentration-time curve and maximal serum concentration of the powders prepared using supercritical CO2 were 4.62-fold and 4.52-fold greater than the corresponding values for raw fenofibrate.Conclusion: The results of this study highlight the usefulness of the melt-adsorption method using supercritical CO2 for improving the bioavailability of fenofibrate.Keywords: fenofibrate

  2. AMPK-Akt Double-Negative Feedback Loop in Breast Cancer Cells Regulates Their Adaptation to Matrix Deprivation.

    Science.gov (United States)

    Saha, Manipa; Kumar, Saurav; Bukhari, Shoiab; Balaji, Sai A; Kumar, Prashant; Hindupur, Sravanth K; Rangarajan, Annapoorni

    2018-03-15

    Cell detachment from the extracellular matrix triggers anoikis. Disseminated tumor cells must adapt to survive matrix deprivation, while still retaining the ability to attach at secondary sites and reinitiate cell division. In this study, we elucidate mechanisms that enable reversible matrix attachment by breast cancer cells. Matrix deprival triggered AMPK activity and concomitantly inhibited AKT activity by upregulating the Akt phosphatase PHLPP2. The resultant pAMPK high /pAkt low state was critical for cell survival in suspension, as PHLPP2 silencing also increased anoikis while impairing autophagy and metastasis. In contrast, matrix reattachment led to Akt-mediated AMPK inactivation via PP2C-α-mediated restoration of the pAkt high /pAMPK low state. Clinical specimens of primary and metastatic breast cancer displayed an Akt-associated gene expression signature, whereas circulating breast tumor cells displayed an elevated AMPK-dependent gene expression signature. Our work establishes a double-negative feedback loop between Akt and AMPK to control the switch between matrix-attached and matrix-detached states needed to coordinate cell growth and survival during metastasis. Significance: These findings reveal a molecular switch that regulates cancer cell survival during metastatic dissemination, with the potential to identify targets to prevent metastasis in breast cancer. Cancer Res; 78(6); 1497-510. ©2018 AACR . ©2018 American Association for Cancer Research.

  3. Comparative transcriptomic and metabolomic analysis of fenofibrate and fish oil treatments in mice

    NARCIS (Netherlands)

    Lu, Y.; Boekschoten, M.V.; Wopereis, S.; Müller, M.; Kersten, S.

    2011-01-01

    Comparative transcriptomic and metabolomic analysis of fenofibrate and fish oil treatments in mice. Physiol Genomics 43: 1307-1318, 2011. First published September 27, 2011; doi:10.1152/physiolgenomics.00100.2011. Elevated circulating triglycerides, which are considered a risk factor for

  4. Hepatotoxic effects of fenofibrate in spontaneously hypertensive rats expressing human C-reactive protein

    Czech Academy of Sciences Publication Activity Database

    Škop, V.; Trnovská, J.; Oliyarnyk, O.; Marková, I.; Malínská, H.; Kazdová, L.; Zídek, Václav; Landa, Vladimír; Mlejnek, Petr; Šimáková, Miroslava; Kůdela, M.; Pravenec, Michal; Šilhavý, Jan

    2016-01-01

    Roč. 65, č. 6 (2016), s. 891-899 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NT14325 Institutional support: RVO:67985823 Keywords : fenofibrate * rosuvastatin * C-reactive protein * transgenic * spontaneously hypertensive rat * inflammation * hepatotoxic Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.461, year: 2016

  5. Fenofibrate and rosiglitazone improve quality of lipoproteins in patients with type 2 diabetes mellitus

    Czech Academy of Sciences Publication Activity Database

    Vrablík, M.; Dobiášová, Milada; Štulc, T.; Kasalová, Z.; Doležalová, R.; Prázný, M.; Fait, T.; Češka, R.

    2008-01-01

    Roč. 29, č. 1 (2008), s. 146-150 ISSN 0172-780X R&D Projects: GA MZd(CZ) NR8328 Institutional research plan: CEZ:AV0Z50110509 Keywords : fenofibrate * rosiglitazone * type 2 diabetes mellitus Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.359, year: 2008

  6. A Cross-Reactivity of Fenofibric Acid With MDMA DRI Assay.

    Science.gov (United States)

    Bugier, Sarah; Garcia-Hejl, Carine; Vest, Philippe; Plantamura, Julie; Chianea, Denis; Renard, Christophe

    2016-09-01

    Within the framework of routine fitness examinations, French Air Force military crew underwent urine testing for 3,4 methylenedioxymetamphetamine (MDMA [ecstasy]). The cross-reactivity of a dyslipidemic drug, fenofibrate, with an MDMA immunoassay was studied and confirmed on a large population sample. A 3-year retrospective study was performed on the MDMA DRI Ecstasy Assay on the Unicel DXC 600. In the event of positive test result, a confirmatory testing was carried out by gas chromatography/mass spectrometry (GC/MS) to establish the presence of MDMA. When analysis by GC/MS did not confirm the presence of MDMA, a false-positive result was suspected and the samples were analyzed by high-performance liquid chromatography-mass spectrometry to identify a potential interfering substance. A total of 15,169 urine samples, from 7,803 patients, were tested for 3 years. Of the tested samples, 22 (0.15%) were positive by DRI Ecstasy Assay. None of them were positive by GC/MS. A cross-reactivity of fenofibrate's metabolite with MDMA using this assay was systematically found. Fenofibrate's interference with MDMA immunoassay was confirmed. Fenofibrate being widely prescribed, physicians had to be alerted that this treatment could lead to false-positive results. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

  7. Fenofibrate, but not ezetimibe, prevents fatty liver disease in mice lacking phosphatidylethanolamineN-methyltransferase.

    Science.gov (United States)

    van der Veen, Jelske N; Lingrell, Susanne; Gao, Xia; Takawale, Abhijit; Kassiri, Zamaneh; Vance, Dennis E; Jacobs, René L

    2017-04-01

    Mice lacking phosphatidylethanolamine N -methyltransferase (PEMT) are protected from high-fat diet (HFD)-induced obesity and insulin resistance. However, these mice develop severe nonalcoholic fatty liver disease (NAFLD) when fed the HFD, which is mainly due to inadequate secretion of VLDL particles. Our aim was to prevent NAFLD development in mice lacking PEMT. We treated Pemt -/- mice with either ezetimibe or fenofibrate to see if either could ameliorate liver disease in these mice. Ezetimibe treatment did not reduce fat accumulation in Pemt -/- livers, nor did it reduce markers for hepatic inflammation or fibrosis. Fenofibrate, conversely, completely prevented the development of NAFLD in Pemt -/- mice: hepatic lipid levels, as well as markers of endoplasmic reticulum stress, inflammation, and fibrosis, in fenofibrate-treated Pemt -/- mice were similar to those in Pemt +/+ mice. Importantly, Pemt -/- mice were still protected against HFD-induced obesity and insulin resistance. Moreover, fenofibrate partially reversed hepatic steatosis and fibrosis in Pemt -/- mice when treatment was initiated after NAFLD had already been established. Increasing hepatic fatty acid oxidation can compensate for the lower VLDL-triacylglycerol secretion rate and prevent/reverse fatty liver disease in mice lacking PEMT. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

  8. Comparative transcriptomic and metabolomic analysis of fenofibrate and fish oil treatments in mice

    NARCIS (Netherlands)

    Lu, Y.; Boekschoten, M.V.; Wopereis, S.; Muller, M.R.; Kersten, A.H.

    2011-01-01

    Elevated circulating triglycerides, which are considered a risk factor for cardiovascular disease, can be targeted by treatment with fenofibrate or fish oil. To gain insight into underlying mechanisms, we carried out a comparative transcriptomics and metabolomics analysis of the effect of 2 wk

  9. Comparative transcriptomics and metabolomic analysis of fenofibrate and fish oil treatments in mice

    NARCIS (Netherlands)

    Lu Yingchang (Kevin), Y.; Boekschoten, Mark; Wopereis, Suzan; Muller, Michael; Kersten, Sander

    2011-01-01

    Elevated circulating triglycerides, which are considered a risk factor for cardiovascular disease, can be targeted by treatment with fenofibrate or fish oil. To gain insight into underlying mechanisms, we carried out a comparative transcriptomics and metabolomics analysis of the effect of 2 week

  10. A mechanism-based pharmacokinetic model of fenofibrate for explaining increased drug absorption after food consumption.

    Science.gov (United States)

    Back, Hyun-Moon; Song, Byungjeong; Pradhan, Sudeep; Chae, Jung-Woo; Han, Nayoung; Kang, Wonku; Chang, Min Jung; Zheng, Jiao; Kwon, Kwang-Il; Karlsson, Mats O; Yun, Hwi-Yeol

    2018-01-25

    Oral administration of drugs is convenient and shows good compliance but it can be affected by many factors in the gastrointestinal (GI) system. Consumption of food is one of the major factors affecting the GI system and consequently the absorption of drugs. The aim of this study was to develop a mechanistic GI absorption model for explaining the effect of food on fenofibrate pharmacokinetics (PK), focusing on the food type and calorie content. Clinical data from a fenofibrate PK study involving three different conditions (fasting, standard meals and high-fat meals) were used. The model was developed by nonlinear mixed effect modeling method. Both linear and nonlinear effects were evaluated to explain the impact of food intake on drug absorption. Similarly, to explain changes in gastric emptying time for the drug due to food effects was evaluated. The gastric emptying rate increased by 61.7% during the first 6.94 h after food consumption. Increased calories in the duodenum increased the absorption rate constant of the drug in fed conditions (standard meal = 16.5%, high-fat meal = 21.8%) compared with fasted condition. The final model displayed good prediction power and precision. A mechanistic GI absorption model for quantitatively evaluating the effects of food on fenofibrate absorption was successfully developed, and acceptable parameters were obtained. The mechanism-based PK model of fenofibrate can quantify the effects of food on drug absorption by food type and calorie content.

  11. MiR-184 expression is regulated by AMPK in pancreatic islets.

    Science.gov (United States)

    Martinez-Sanchez, Aida; Nguyen-Tu, Marie-Sophie; Cebola, Ines; Yavari, Arash; Marchetti, Piero; Piemonti, Lorenzo; de Koning, Eelco; Shapiro, A M James; Johnson, Paul; Sakamoto, Kei; Smith, David M; Leclerc, Isabelle; Ashrafian, Houman; Ferrer, Jorge; Rutter, Guy A

    2018-01-08

    AMPK is a critical energy sensor and target for widely used antidiabetic drugs. In β-cells, elevated glucose concentrations lower AMPK activity, and the ablation of both catalytic subunits (βAMPKdKO mice) impairs insulin secretion in vivo and β-cell identity. MicroRNAs (miRNAs) are small RNAs that silence gene expression that are essential for pancreatic β-cell function and identity and altered in diabetes. Here, we have explored the miRNAs acting downstream of AMPK in mouse and human β-cells. We identified 14 down-regulated and 9 up-regulated miRNAs in βAMPKdKO vs. control islets. Gene ontology analysis of targeted transcripts revealed enrichment in pathways important for β-cell function and identity. The most down-regulated miRNA was miR-184 (miR-184-3p), an important regulator of β-cell function and compensatory expansion that is controlled by glucose and reduced in diabetes. We demonstrate that AMPK is a potent regulator and an important mediator of the negative effects of glucose on miR-184 expression. Additionally, we reveal sexual dimorphism in miR-184 expression in mouse and human islets. Collectively, these data demonstrate that glucose-mediated changes in AMPK activity are central for the regulation of miR-184 and other miRNAs in islets and provide a link between energy status and gene expression in β-cells.-Martinez-Sanchez, A., Nguyen-Tu, M.-S., Cebola, I., Yavari, A., Marchetti, P., Piemonti, L., de Koning, E., Shapiro, A. M. J., Johnson, P., Sakamoto, K., Smith, D. M., Leclerc, I., Ashrafian, H., Ferrer, J., Rutter, G. A. MiR-184 expression is regulated by AMPK in pancreatic islets.

  12. Mechanisms of regulation of SNF1/AMPK/SnRK1 protein kinases

    Science.gov (United States)

    Crozet, Pierre; Margalha, Leonor; Confraria, Ana; Rodrigues, Américo; Martinho, Cláudia; Adamo, Mattia; Elias, Carlos A.; Baena-González, Elena

    2014-01-01

    The SNF1 (sucrose non-fermenting 1)-related protein kinases 1 (SnRKs1) are the plant orthologs of the budding yeast SNF1 and mammalian AMPK (AMP-activated protein kinase). These evolutionarily conserved kinases are metabolic sensors that undergo activation in response to declining energy levels. Upon activation, SNF1/AMPK/SnRK1 kinases trigger a vast transcriptional and metabolic reprograming that restores energy homeostasis and promotes tolerance to adverse conditions, partly through an induction of catabolic processes and a general repression of anabolism. These kinases typically function as a heterotrimeric complex composed of two regulatory subunits, β and γ, and an α-catalytic subunit, which requires phosphorylation of a conserved activation loop residue for activity. Additionally, SNF1/AMPK/SnRK1 kinases are controlled by multiple mechanisms that have an impact on kinase activity, stability, and/or subcellular localization. Here we will review current knowledge on the regulation of SNF1/AMPK/SnRK1 by upstream components, post-translational modifications, various metabolites, hormones, and others, in an attempt to highlight both the commonalities of these essential eukaryotic kinases and the divergences that have evolved to cope with the particularities of each one of these systems. PMID:24904600

  13. Resveratrol inhibits renal interstitial fibrosis in diabetic nephropathy by regulating AMPK/NOX4/ROS pathway.

    Science.gov (United States)

    He, Ting; Xiong, Jiachuan; Nie, Ling; Yu, Yanlin; Guan, Xu; Xu, Xinli; Xiao, Tangli; Yang, Ke; Liu, Liang; Zhang, Daohai; Huang, Yunjian; Zhang, Jingbo; Wang, Junping; Sharma, Kumar; Zhao, Jinghong

    2016-12-01

    Renal interstitial fibrosis is a major pathologic feature of diabetic nephropathy, while the pathogenesis and therapeutic interventions of diabetic renal interstitial fibrosis are not well established. In this study, we first demonstrated that high glucose could induce renal fibroblast (NRK-49F) cell proliferation and activation to myofibroblasts, accompanied by a significant increase in the intracellular levels of reactive oxygen species (ROS) derived from nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4). ROS-mediated ERK1/2 activation was found to play a crucial role in high glucose-induced fibroblast proliferation and activation. Resveratrol, like the NOX4-targeting small interfering RNA (siRNA), markedly inhibited high glucose-induced fibroblast proliferation and activation by reducing NOX4-derived ROS production. It was then revealed that the increase in the expression of NOX4 induced by high glucose was due to the inactivation of AMP-activated protein kinase (AMPK), which could be reversed by resveratrol. Further in vivo investigation demonstrated that resveratrol treatment significantly attenuated renal fibrosis in db/db mice, accompanied by an evident increase in phospho-AMPK and decrease in NOX4. In summary, our results suggest that high glucose can directly promote renal fibroblasts proliferation and activation in a ROS-dependent manner, and resveratrol is a potential therapeutic agent against diabetic renal fibrosis via regulation of AMPK/NOX4/ROS signaling. Resveratrol inhibits high glucose-induced NRK cell activation by decreasing NOX4-derived ROS. Resveratrol inhibits high glucose-induced NOX4 expression in NRK cells via activation of AMPK. ROS-activated ERK1/2 signaling is involved in high glucose-induced NRK cell activation. Resveratrol attenuated renal fibrosis in db/db mice via regulation of AMPK/NOX4/ROS signaling.

  14. Ginkgolide C Suppresses Adipogenesis in 3T3-L1 Adipocytes via the AMPK Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Chian-Jiun Liou

    2015-01-01

    Full Text Available Ginkgolide C, isolated from Ginkgo biloba leaves, is a flavone reported to have multiple biological functions, from decreased platelet aggregation to ameliorating Alzheimer disease. The study aim was to evaluate the antiadipogenic effect of ginkgolide C in 3T3-L1 adipocytes. Ginkgolide C was used to treat differentiated 3T3-L1 cells. Cell supernatant was collected to assay glycerol release, and cells were lysed to measure protein and gene expression related to adipogenesis and lipolysis by western blot and real-time PCR, respectively. Ginkgolide C significantly suppressed lipid accumulation in differentiated adipocytes. It also decreased adipogenesis-related transcription factor expression, including peroxisome proliferator-activated receptor and CCAAT/enhancer-binding protein. Furthermore, ginkgolide C enhanced adipose triglyceride lipase and hormone-sensitive lipase production for lipolysis and increased phosphorylation of AMP-activated protein kinase (AMPK, resulting in decreased activity of acetyl-CoA carboxylase for fatty acid synthesis. In coculture with an AMPK inhibitor (compound C, ginkgolide C also improved activation of sirtuin 1 and phosphorylation of AMPK in differentiated 3T3-L1 cells. The results suggest that ginkgolide C is an effective flavone for increasing lipolysis and inhibiting adipogenesis in adipocytes through the activated AMPK pathway.

  15. Salsalate (Salicylate) Uncouples Mitochondria, Improves Glucose Homeostasis, and Reduces Liver Lipids Independent of AMPK-β1.

    Science.gov (United States)

    Smith, Brennan K; Ford, Rebecca J; Desjardins, Eric M; Green, Alex E; Hughes, Meghan C; Houde, Vanessa P; Day, Emily A; Marcinko, Katarina; Crane, Justin D; Mottillo, Emilio P; Perry, Christopher G R; Kemp, Bruce E; Tarnopolsky, Mark A; Steinberg, Gregory R

    2016-11-01

    Salsalate is a prodrug of salicylate that lowers blood glucose in patients with type 2 diabetes (T2D) and reduces nonalcoholic fatty liver disease (NAFLD) in animal models; however, the mechanism mediating these effects is unclear. Salicylate directly activates AMPK via the β1 subunit, but whether salsalate requires AMPK-β1 to improve T2D and NAFLD has not been examined. Therefore, wild-type (WT) and AMPK-β1-knockout (AMPK-β1KO) mice were treated with a salsalate dose resulting in clinically relevant serum salicylate concentrations (∼1 mmol/L). Salsalate treatment increased VO 2 , lowered fasting glucose, improved glucose tolerance, and led to an ∼55% reduction in liver lipid content. These effects were observed in both WT and AMPK-β1KO mice. To explain these AMPK-independent effects, we found that salicylate increases oligomycin-insensitive respiration (state 4o) and directly increases mitochondrial proton conductance at clinical concentrations. This uncoupling effect is tightly correlated with the suppression of de novo lipogenesis. Salicylate is also able to stimulate brown adipose tissue respiration independent of uncoupling protein 1. These data indicate that the primary mechanism by which salsalate improves glucose homeostasis and NAFLD is via salicylate-driven mitochondrial uncoupling. © 2016 by the American Diabetes Association.

  16. Salsalate (Salicylate) Uncouples Mitochondria, Improves Glucose Homeostasis, and Reduces Liver Lipids Independent of AMPK-β1

    Science.gov (United States)

    Smith, Brennan K.; Ford, Rebecca J.; Desjardins, Eric M.; Green, Alex E.; Hughes, Meghan C.; Houde, Vanessa P.; Day, Emily A.; Marcinko, Katarina; Crane, Justin D.; Mottillo, Emilio P.; Perry, Christopher G.R.; Kemp, Bruce E.; Tarnopolsky, Mark A.; Steinberg, Gregory R.

    2017-01-01

    Salsalate is a prodrug of salicylate that lowers blood glucose in patients with type 2 diabetes (T2D) and reduces nonalcoholic fatty liver disease (NAFLD) in animal models; however, the mechanism mediating these effects is unclear. Salicylate directly activates AMPK via the β1 subunit, but whether salsalate requires AMPK-β1 to improve T2D and NAFLD has not been examined. Therefore, wild-type (WT) and AMPK-β1–knockout (AMPK-β1KO) mice were treated with a salsalate dose resulting in clinically relevant serum salicylate concentrations (~1 mmol/L). Salsalate treatment increased VO2, lowered fasting glucose, improved glucose tolerance, and led to an ~55% reduction in liver lipid content. These effects were observed in both WT and AMPK-β1KO mice. To explain these AMPK-independent effects, we found that salicylate increases oligomycin-insensitive respiration (state 4o) and directly increases mitochondrial proton conductance at clinical concentrations. This uncoupling effect is tightly correlated with the suppression of de novo lipogenesis. Salicylate is also able to stimulate brown adipose tissue respiration independent of uncoupling protein 1. These data indicate that the primary mechanism by which salsalate improves glucose homeostasis and NAFLD is via salicylate-driven mitochondrial uncoupling. PMID:27554471

  17. The p17 nonstructural protein of avian reovirus triggers autophagy enhancing virus replication via activation of phosphatase and tensin deleted on chromosome 10 (PTEN) and AMP-activated protein kinase (AMPK), as well as dsRNA-dependent protein kinase (PKR)/eIF2α signaling pathways.

    Science.gov (United States)

    Chi, Pei I; Huang, Wei R; Lai, I H; Cheng, Ching Y; Liu, Hung J

    2013-02-01

    Autophagy has been shown to facilitate replication or production of avian reovirus (ARV); nevertheless, how ARV induces autophagy remains largely unknown. Here, we demonstrate that the nonstructural protein p17 of ARV functions as an activator of autophagy. ARV-infected or p17-transfected cells present a fast and strong induction of autophagy, resulting in an increased level of autophagic proteins Beclin 1 and LC3-II. Although autophagy was suppressed by 3-methyladenine or shRNAs targeting autophagic proteins (Beclin 1, ATG7, and LC3) as well as by overexpression of Bcl-2, viral transcription, σC protein synthesis, and virus yield were all significantly reduced, suggesting a key role of autophagosomes in supporting ARV replication. Furthermore, we revealed for the first time that p17 positively regulates phosphatase and tensin deleted on chromosome 10 (PTEN), AMP-activated protein kinase (AMPK), and dsRNA dependent protein kinase RNA (PKR)/eIF2α signaling pathways, accompanied by down-regulation of Akt and mammalian target of rapamycin complex 1, thereby triggering autophagy. By using p53, PTEN, PKR, AMPK, and p17 short hairpin RNA (shRNA), activation of signaling pathways and LC3-II levels was significantly suppressed, suggesting that p17 triggers autophagy through activation of p53/PTEN, AMPK, and PKR signaling pathways. Furthermore, colocalization of LC3 with viral proteins (p17 and σC), p62 with LAMP2 and LC3 with Rab7 was observed under a fluorescence microscope. The expression level of p62 was increased at 18 h postinfection and then slightly decreased 24 h postinfection compared with mock infection and thapsigargin treatment. Furthermore, disruption of autophagosome-lysosome fusion by shRNAs targeting LAMP2 or Rab7a resulted in inhibition of viral protein synthesis and virus yield, suggesting that formation of autolysosome benefits virus replication. Taken together, our results suggest that ARV induces formation of autolysosome but does not induce

  18. An evolutionary perspective of AMPK-TOR signaling in the three domains of life.

    Science.gov (United States)

    Roustan, Valentin; Jain, Arpit; Teige, Markus; Ebersberger, Ingo; Weckwerth, Wolfram

    2016-06-01

    AMPK and TOR protein kinases are the major control points of energy signaling in eukaryotic cells and organisms. They form the core of a complex regulatory network to co-ordinate metabolic activities in the cytosol with those in the mitochondria and plastids. Despite its relevance, it is still unclear when and how this regulatory pathway was formed during evolution, and to what extent its representations in the major eukaryotic lineages resemble each other. Here we have traced 153 essential proteins forming the human AMPK-TOR pathways across 412 species representing all three domains of life-prokaryotes (bacteria, archaea) and eukaryotes-and reconstructed their evolutionary history. The resulting phylogenetic profiles indicate the presence of primordial core pathways including seven proto-kinases in the last eukaryotic common ancestor. The evolutionary origins of the oldest components of the AMPK pathway, however, extend into the pre-eukaryotic era, and descendants of these ancient proteins can still be found in contemporary prokaryotes. The TOR complex in turn appears as a eukaryotic invention, possibly to aid in retrograde signaling between the mitochondria and the remainder of the cell. Within the eukaryotes, AMPK/TOR showed both a highly conserved core structure and a considerable plasticity. Most notably, KING1, a protein originally assigned as the γ subunit of AMPK in plants, is more closely related to the yeast SDS23 gene family than to the γ subunits in animals or fungi. This suggests its functional difference from a canonical AMPK γ subunit. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Fenofibrate in the treatment of dyslipidemia: a review of the data as they relate to the new suprabioavailable tablet formulation.

    Science.gov (United States)

    Najib, Jadwiga

    2002-12-01

    The fibric acid derivative fenofibrate is indicated as an adjunct to dietary modification in adults with primary hypercholesterolemia or mixed dyslipidemia (types IIa and IIb hyperlipidemia, Fredrickson classification) to reduce levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), and apolipoprotein (apo) B, and to increase levels of high-density lipoprotein cholesterol (HDL-C) and apo A. It is also indicated as adjunctive therapy to diet for the treatment of hypertriglyceridemia (types IV and V hyperlipidemia). Initially approved in the United States in a micronized capsule formulation, fenofibrate is now available in a new "suprabioavailable" tablet formulation that has increased bioavailability, achieving equivalent plasma concentrations at lower doses. The 67- and 200-mg micronized capsules can be considered equivalent to the 54- and 160-mg suprabioavailable tablets, respectively. This paper reviews the pharmacologic properties, clinical usefulness, and safety profile of fenofibrate in the management of dyslipidemias. Recent studies, abstracts, reviews, and consensus statements published in the English-language literature were identified through searches of MEDLINE (1966-January 2002), International Pharmaceutical Abstracts (1970-January 2002), and PharmaProjects (1990-January 2002) using the search terms fenofibrate, fibrates, hyperlipidemia, hypertriglyceridemia, and dyslipidemia. Fenofibrate is well absorbed after oral administration, with peak plasma levels attained in 6 to 8 hours. The absolute bioavailability of fenofibrate cannot be determined due to its being virtually insoluble in aqueous media suitable for injection; however, after oral administration of a single dose of radiolabeled fenofibrate, approximately 60% of the dose appeared in urine, primarily as fenofibric acid and its glucuronated conjugate, and approximately 25% was excreted in the feces. The apparent volume of distribution is 0.89 L/kg in

  20. Mining frequent patterns for AMP-activated protein kinase regulation on skeletal muscle

    OpenAIRE

    Chen, Qingfeng; Chen, Yi-Ping Phoebe

    2006-01-01

    Abstract Background AMP-activated protein kinase (AMPK) has emerged as a significant signaling intermediary that regulates metabolisms in response to energy demand and supply. An investigation into the degree of activation and deactivation of AMPK subunits under exercise can provide valuable data for understanding AMPK. In particular, the effect of AMPK on muscle cellular energy status makes this protein a promising pharmacological target for disease treatment. As more AMPK regulation data ar...

  1. The AMPK enzyme-complex: from the regulation of cellular energy homeostasis to a possible new molecular target in the management of chronic inflammatory disorders.

    Science.gov (United States)

    Antonioli, Luca; Colucci, Rocchina; Pellegrini, Carolina; Giustarini, Giulio; Sacco, Deborah; Tirotta, Erika; Caputi, Valentina; Marsilio, Ilaria; Giron, Maria Cecilia; Németh, Zoltán H; Blandizzi, Corrado; Fornai, Matteo

    2016-01-01

    Adenosine monophosphate-activated protein kinase (AMPK), known as an enzymatic complex that regulates the energetic metabolism, is emerging as a pivotal enzyme and enzymatic pathway involved in the regulation of immune homeostatic networks. It is also involved in the molecular mechanisms underlying the pathophysiology of chronic inflammatory diseases. AMPK is expressed in several immune cell types including macrophages, lymphocytes, neutrophils and dendritic cells, and governs a broad array of cell functions, which include cytokine production, chemotaxis, cytotoxicity, apoptosis and proliferation. Based on its wide variety of immunoregulatory actions, the AMPK system has been targeted to reveal its impact on the course of immune-related diseases, such as atherosclerosis, psoriasis, joint inflammation and inflammatory bowel diseases. The identification of AMPK subunits responsible for specific anti-inflammatory actions and the understanding of the underlying molecular mechanisms will promote the generation of novel AMPK activators, endowed with improved pharmacodynamic and pharmacokinetic profiles. These new tools will aid us to utilize AMPK pathway activation in the management of acute and chronic inflammatory diseases, while minimizing potential adverse reactions related to the effects of AMPK on metabolic energy.

  2. Ethanol Extract of Pinus koraiensis Leaf Ameliorates Alcoholic Fatty Liver via the Activation of LKB1-AMPK Signaling In Vitro and In Vivo.

    Science.gov (United States)

    Hong, Sang-Hyuk; Lee, Hyemin; Lee, Hyo-Jung; Kim, Bonglee; Nam, Min-Ho; Shim, Bum-Sang; Kim, Sung-Hoon

    2017-05-01

    Although Pinus koraiensis leaf (PKL) was reported for its anti-diabetes, anti-obesity and anticancer effects as a folk remedy, the inhibitory effect of PKL on alcoholic fatty liver has never been elucidated yet. This study investigated the molecular mechanisms of PKL on alcoholic fatty liver in HepG2 cells, Sprague Dawley (SD) rats and Imprinting Control Region (ICR) mice. Pinus koraiensis leaf increased phosphorylation of liver kinase B1 (LKB1)/AMP-activated protein kinase signaling, low-density lipoprotein receptor and decreased fatty acid biosynthesis-related proteins such as sterol regulatory element-binding protein 1c, fatty acid synthase, 3-hydroxy-3-methylglutaryl-CoA reductase in HepG2 cells. In SD rats with 25% alcohol-induced fatty liver, PKL suppressed the levels of aspartate aminotransferase and triglyceride and also enhanced the activities of antioxidant enzymes including superoxide dismutase, glutathione peroxidase and glutathione s-transferase compared with untreated control. Furthermore, PKL increased serum alcohol dehydrogenase and serum aldehyde dehydrogenase, but decreased serum alcohol concentration in ICR mice after alcohol administration. Consistently, histochemical analysis revealed that PKL attenuated alcohol-induced fatty liver in SD rats. Overall, these findings suggest that PKL ameliorates alcohol-induced fatty liver via activation of LKB1-AMP-activated protein kinase and modulation of proteins related to lipogenesis synthesis, cholesterol synthesis and fatty acid oxidation. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  3. In vitro and in vivo evaluation of a self-microemulsifying drug delivery system for the poorly soluble drug fenofibrate.

    Science.gov (United States)

    Cho, Young-Dae; Park, Young-Joon

    2014-02-01

    Fenofibrate is indicated in hypercholesterolemia and hypertriglyceridemia alone or combined (types IIa, IIb, III, IV, and V dyslipidemias). However, due to its low solubility in water, it has low bioavailability after oral administration. In order to improve the dissolution rate, fenofibrate was formulated into a self-microemulsifying drug delivery system (SMEDDS). We used pseudoternary phase diagrams to evaluate the area of microemulsification, and an in vitro dissolution test was used to investigate the dissolution rate of fenofibrate. The optimized formulation for in vitro dissolution and bioavailability assessment consisted of propylene glycol laurate (Lauroglycol FCC) (60 %), macrogol-15-hydroxystearate (Solutol HS 15) (27 %), and diethylene glycol monoethyl ether (Transcutol-P) (13 %). The mean droplet size of the oil phase in the microemulsion formed by the SMEDDS was 131.1 nm. The dissolution rate of fenofibrate from SMEDDS was significantly higher than that of the reference tablet. In vivo pharmacokinetics study of fenofibrate in beagles administered SMEDDS-A form resulted in a 3.7-fold increase in bioavailability as compared with the reference drug. Our studies suggested that the fenofibrate containing SMEDDS composition can effectively increase the solubility and oral bioavailability of poorly water-soluble drugs.

  4. Integrative Analysis of PRKAG2 Cardiomyopathy iPS and Microtissue Models Identifies AMPK as a Regulator of Metabolism, Survival, and Fibrosis

    Directory of Open Access Journals (Sweden)

    J. Travis Hinson

    2016-12-01

    Full Text Available AMP-activated protein kinase (AMPK is a metabolic enzyme that can be activated by nutrient stress or genetic mutations. Missense mutations in the regulatory subunit, PRKAG2, activate AMPK and cause left ventricular hypertrophy, glycogen accumulation, and ventricular pre-excitation. Using human iPS cell models combined with three-dimensional cardiac microtissues, we show that activating PRKAG2 mutations increase microtissue twitch force by enhancing myocyte survival. Integrating RNA sequencing with metabolomics, PRKAG2 mutations that activate AMPK remodeled global metabolism by regulating RNA transcripts to favor glycogen storage and oxidative metabolism instead of glycolysis. As in patients with PRKAG2 cardiomyopathy, iPS cell and mouse models are protected from cardiac fibrosis, and we define a crosstalk between AMPK and post-transcriptional regulation of TGFβ isoform signaling that has implications in fibrotic forms of cardiomyopathy. Our results establish critical connections among metabolic sensing, myocyte survival, and TGFβ signaling.

  5. The glycolytic shift in fumarate-hydratase-deficient kidney cancer lowers AMPK levels, increases anabolic propensities and lowers cellular iron levels

    KAUST Repository

    Tong, Winghang

    2011-09-01

    Inactivation of the TCA cycle enzyme, fumarate hydratase (FH), drives a metabolic shift to aerobic glycolysis in FH-deficient kidney tumors and cell lines from patients with hereditary leiomyomatosis renal cell cancer (HLRCC), resulting in decreased levels of AMP-activated kinase (AMPK) and p53 tumor suppressor, and activation of the anabolic factors, acetyl-CoA carboxylase and ribosomal protein S6. Reduced AMPK levels lead to diminished expression of the DMT1 iron transporter, and the resulting cytosolic iron deficiency activates the iron regulatory proteins, IRP1 and IRP2, and increases expression of the hypoxia inducible factor HIF-1α, but not HIF-2α. Silencing of HIF-1α or activation of AMPK diminishes invasive activities, indicating that alterations of HIF-1α and AMPK contribute to the oncogenic growth of FH-deficient cells. © 2011 Elsevier Inc.

  6. High Density Lipoprotein Structural Changes and Drug Response in Lipidomic Profiles following the Long-Term Fenofibrate Therapy in the FIELD Substudy

    DEFF Research Database (Denmark)

    Yetukuri, L.; Huopaniemi, I.; Koivuniemi, A.

    2011-01-01

    In a recent FIELD study the fenofibrate therapy surprisingly failed to achieve significant benefit over placebo in the primary endpoint of coronary heart disease events. Increased levels of atherogenic homocysteine were observed in some patients assigned to fenofibrate therapy but the molecular...... of lysophosphatidylcholines and increase of sphingomyelins. Ethanolamine plasmalogens were diminished only in a subgroup of fenofibrate-treated patients with elevated homocysteine levels. Finally we performed molecular dynamics simulations to qualitatively reconstitute HDL particles in silico. We found that increased number...

  7. The impact of endurance exercise on global and AMPK gene-specific DNA methylation

    Energy Technology Data Exchange (ETDEWEB)

    King-Himmelreich, Tanya S.; Schramm, Stefanie; Wolters, Miriam C.; Schmetzer, Julia; Möser, Christine V.; Knothe, Claudia [pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt am Main (Germany); Resch, Eduard [Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project Group for Translational Medicine & Pharmacology (TMP), 60596, Frankfurt/Main (Germany); Peil, Johannes [Sports Clinic, Bad Nauheim, MCI GmbH, In der Aue 30-32, 61231, Bad Nauheim (Germany); Geisslinger, Gerd [pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt am Main (Germany); Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project Group for Translational Medicine & Pharmacology (TMP), 60596, Frankfurt/Main (Germany); Niederberger, Ellen, E-mail: e.niederberger@em.uni-frankfurt.de [pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt am Main (Germany)

    2016-05-27

    Alterations in gene expression as a consequence of physical exercise are frequently described. The mechanism of these regulations might depend on epigenetic changes in global or gene-specific DNA methylation levels. The AMP-activated protein kinase (AMPK) plays a key role in maintenance of energy homeostasis and is activated by increases in the AMP/ATP ratio as occurring in skeletal muscles after sporting activity. To analyze whether exercise has an impact on the methylation status of the AMPK promoter, we determined the AMPK methylation status in human blood samples from patients before and after sporting activity in the context of rehabilitation as well as in skeletal muscles of trained and untrained mice. Further, we examined long interspersed nuclear element 1 (LINE-1) as indicator of global DNA methylation changes. Our results revealed that light sporting activity in mice and humans does not alter global DNA methylation but has an effect on methylation of specific CpG sites in the AMPKα2 gene. These regulations were associated with a reduced AMPKα2 mRNA and protein expression in muscle tissue, pointing at a contribution of the methylation status to AMPK expression. Taken together, these results suggest that exercise influences AMPKα2 gene methylation in human blood and eminently in the skeletal muscle of mice and therefore might repress AMPKα2 gene expression. -- Highlights: •AMPK gene methylation increases after moderate endurance exercise in humans and mice. •AMPKα mRNA and protein decrease after moderate endurance exercise in mice. •Global DNA methylation is not affected under the same conditions.

  8. The impact of endurance exercise on global and AMPK gene-specific DNA methylation

    International Nuclear Information System (INIS)

    King-Himmelreich, Tanya S.; Schramm, Stefanie; Wolters, Miriam C.; Schmetzer, Julia; Möser, Christine V.; Knothe, Claudia; Resch, Eduard; Peil, Johannes; Geisslinger, Gerd; Niederberger, Ellen

    2016-01-01

    Alterations in gene expression as a consequence of physical exercise are frequently described. The mechanism of these regulations might depend on epigenetic changes in global or gene-specific DNA methylation levels. The AMP-activated protein kinase (AMPK) plays a key role in maintenance of energy homeostasis and is activated by increases in the AMP/ATP ratio as occurring in skeletal muscles after sporting activity. To analyze whether exercise has an impact on the methylation status of the AMPK promoter, we determined the AMPK methylation status in human blood samples from patients before and after sporting activity in the context of rehabilitation as well as in skeletal muscles of trained and untrained mice. Further, we examined long interspersed nuclear element 1 (LINE-1) as indicator of global DNA methylation changes. Our results revealed that light sporting activity in mice and humans does not alter global DNA methylation but has an effect on methylation of specific CpG sites in the AMPKα2 gene. These regulations were associated with a reduced AMPKα2 mRNA and protein expression in muscle tissue, pointing at a contribution of the methylation status to AMPK expression. Taken together, these results suggest that exercise influences AMPKα2 gene methylation in human blood and eminently in the skeletal muscle of mice and therefore might repress AMPKα2 gene expression. -- Highlights: •AMPK gene methylation increases after moderate endurance exercise in humans and mice. •AMPKα mRNA and protein decrease after moderate endurance exercise in mice. •Global DNA methylation is not affected under the same conditions.

  9. Protectin DX suppresses hepatic gluconeogenesis through AMPK-HO-1-mediated inhibition of ER stress.

    Science.gov (United States)

    Jung, Tae Woo; Kim, Hyung-Chun; Abd El-Aty, A M; Jeong, Ji Hoon

    2017-06-01

    Several studies have shown that protectins, which are ω-3 fatty acid-derived proresolution mediators, may improve insulin resistance. Recently, protectin DX (PDX) was documented to attenuate insulin resistance by stimulating IL-6 expression in skeletal muscle, thereby regulating hepatic gluconeogenesis. These findings made us investigate the direct effects of PDX on hepatic glucose metabolism in the context of diabetes. In the current study, we show that PDX regulates hepatic gluconeogenesis in a manner distinct from its indirect glucoregulatory activity via IL-6. We found that PDX stimulated AMP-activated protein kinase (AMPK) phosphorylation, thereby inducing heme oxygenase 1 (HO-1) expression. This induction blocked hepatic gluconeogenesis by suppressing endoplasmic reticulum (ER) stress in hepatocytes under hyperlipidemic conditions. These effects were significantly dampened by silencing AMPK or HO-1 expression with small interfering RNA (siRNA). We also demonstrated that administration of PDX to high fat diet (HFD)-fed mice resulted in increased hepatic AMPK phosphorylation and HO-1 expression, whereas hepatic ER stress was substantially attenuated. Furthermore, PDX treatment suppressed the expression of gluconeogenic genes, thereby decreasing blood glucose levels in HFD-fed mice. In conclusion, our findings suggest that PDX inhibits hepatic gluconeogenesis via AMPK-HO-1-dependent suppression of ER stress. Thus, PDX may be an effective therapeutic target for the treatment of insulin resistance and type 2 diabetes through the regulation of hepatic gluconeogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Exendin-4 Alleviates High Glucose-Induced Rat Mesangial Cell Dysfunction through the AMPK Pathway

    Directory of Open Access Journals (Sweden)

    Wen-Wei Xu

    2014-02-01

    Full Text Available Background/Aims: Glucagon-like peptide-1 (GLP-1, which counteracts insulin resistance in humans with type 2 diabetes, has been shown to ameliorate diabetic nephropathy in experimental models. However, the mechanisms through which GLP-1 modulates renal function remained illdefined. The present study investigated the putative mechanisms underlying effects of exendin-4, a GLP-1 analog, on mesangial cell proliferation and fibronectin. Methods: Rat mesangial cells (MCs were treated with exendin-4 under high glucose conditions. AMP-activated protein kinase (AMPK inhibitors (compound C and agonists (AICAR were used to analyze the role of this kinase. Cell proliferation was measured using a MTT assay. Fibronectin expression and AMPK-signaling pathway activity were assessed using ELISA and Western blotting, respectively. The production of matrix metalloproteinase (MMP-2 and tissue inhibitors of metalloproteinases (TIMP-2 was evaluated using quantitative real-time RT-PCR. Results: Exendin-4 inhibited cell proliferation and fibronectin secretion in high glucose-induced MCs. It also caused phosphorylation of AMPK and subsequently increased the ratio of MMP-2 to TIMP-2, which resulted in the degradation of fibronectin. Exendin-4 reversed extracellular signal-regulated kinase (ERK phosphorylation and enhanced expression of mammalian target of rapamycin (mTOR in MCs. Moreover, the activation of the AMPK pathway by exendin-4 was induced by AICAR, which was inhibited by compound C. Conclusion: Exendin-4 exerts an inhibitory effect on cell proliferation and fibronectin secretion in rat MCs, partly through AMPK activation. These results may explain some of the beneficial effects of exendin-4 on the kidney.

  11. Folliculin Controls Lung Alveolar Enlargement and Epithelial Cell Survival through E-Cadherin, LKB1, and AMPK

    Directory of Open Access Journals (Sweden)

    Elena A. Goncharova

    2014-04-01

    Full Text Available Spontaneous pneumothoraces due to lung cyst rupture afflict patients with the rare disease Birt-Hogg-Dubé (BHD syndrome, which is caused by mutations of the tumor suppressor gene folliculin (FLCN. The underlying mechanism of the lung manifestations in BHD is unclear. We show that BHD lungs exhibit increased alveolar epithelial cell apoptosis and that Flcn deletion in mouse lung epithelium leads to cell apoptosis, alveolar enlargement, and an impairment of both epithelial barrier and overall lung function. We find that Flcn-null epithelial cell apoptosis is the result of impaired AMPK activation and increased cleaved caspase-3. AMPK activator LKB1 and E-cadherin are downregulated by Flcn loss and restored by its expression. Correspondingly, Flcn-null cell survival is rescued by the AMPK activator AICAR or constitutively active AMPK. AICAR also improves lung condition of Flcnf/f:SP-C-Cre mice. Our data suggest that lung cysts in BHD may result from an underlying defect in alveolar epithelial cell survival, attributable to FLCN regulation of the E-cadherin-LKB1-AMPK axis.

  12. Ampk phosphorylation of Ulk1 is required for targeting of mitochondria to lysosomes in exercise-induced mitophagy.

    Science.gov (United States)

    Laker, Rhianna C; Drake, Joshua C; Wilson, Rebecca J; Lira, Vitor A; Lewellen, Bevan M; Ryall, Karen A; Fisher, Carleigh C; Zhang, Mei; Saucerman, Jeffrey J; Goodyear, Laurie J; Kundu, Mondira; Yan, Zhen

    2017-09-15

    Mitochondrial health is critical for skeletal muscle function and is improved by exercise training through both mitochondrial biogenesis and removal of damaged/dysfunctional mitochondria via mitophagy. The mechanisms underlying exercise-induced mitophagy have not been fully elucidated. Here, we show that acute treadmill running in mice causes mitochondrial oxidative stress at 3-12 h and mitophagy at 6 h post-exercise in skeletal muscle. These changes were monitored using a novel fluorescent reporter gene, pMitoTimer, that allows assessment of mitochondrial oxidative stress and mitophagy in vivo, and were preceded by increased phosphorylation of AMP activated protein kinase (Ampk) at tyrosine 172 and of unc-51 like autophagy activating kinase 1 (Ulk1) at serine 555. Using mice expressing dominant negative and constitutively active Ampk in skeletal muscle, we demonstrate that Ulk1 activation is dependent on Ampk. Furthermore, exercise-induced metabolic adaptation requires Ulk1. These findings provide direct evidence of exercise-induced mitophagy and demonstrate the importance of Ampk-Ulk1 signaling in skeletal muscle.Exercise is associated with biogenesis and removal of dysfunctional mitochondria. Here the authors use a mitochondrial reporter gene to demonstrate the occurrence of mitophagy following exercise in mice, and show this is dependent on AMPK and ULK1 signaling.

  13. Contraction-stimulated glucose transport in muscle is controlled by AMPK and mechanical stress but not sarcoplasmatic reticulum Ca2+ release

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Sylow, Lykke; Rose, Adam John

    2014-01-01

    signals through proteins such as AMPK. Here, we demonstrate in incubated mouse muscle that Ca(2+) release is neither sufficient nor strictly necessary to increase glucose transport. Rather, the glucose transport response is associated with metabolic feedback signals through AMPK, and mechanical stress......-activated signals. Furthermore, artificial stimulation of AMPK combined with passive stretch of muscle is additive and sufficient to elicit the full contraction glucose transport response. These results suggest that ATP-turnover and mechanical stress feedback are sufficient to fully increase glucose transport...

  14. Glucose-Based Regulation of miR-451/AMPK Signaling Depends on the OCT1 Transcription Factor

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    Khairul I. Ansari

    2015-05-01

    Full Text Available In aggressive, rapidly growing solid tumors such as glioblastoma multiforme (GBM, cancer cells face frequent dynamic changes in their microenvironment, including the availability of glucose and other nutrients. These challenges require that tumor cells have the ability to adapt in order to survive periods of nutrient/energy starvation. We have identified a reciprocal negative feedback loop mechanism in which the levels of microRNA-451 (miR-451 are negatively regulated through the phosphorylation and inactivation of its direct transcriptional activator OCT1 by 5′ AMP-activated protein kinase (AMPK, which is activated by glucose depletion-induced metabolic stress. Conversely, in a glucose-rich environment, unrestrained expression of miR-451 suppresses AMPK pathway activity. These findings uncover miR-451 as a major effector of glucose-regulated AMPK signaling, allowing tumor cell adaptation to variations in nutrient availability in the tumor microenvironment.

  15. Adiponectin increases secretion of rat submandibular gland via adiponectin receptors-mediated AMPK signaling.

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    Chong Ding

    Full Text Available Adiponectin and adiponectin receptors (AdipoR1/2 are expressed in various tissues and are involved in the regulation of multiple functions such as energy metabolism and inflammatory responses. However, the effect of adiponectin and AdipoRs in submandibular glands has not been fully evaluated. In the present study, we found that mRNA and protein of both adiponectin and AdipoR1/2 were expressed in rat submandibular glands and in the SMG-C6 cell line, as evidenced by RT-PCR and Western blot analysis. Immunofluorescence staining showed that adiponectin was diffused in the cytoplasm, while AdipoR1/2 was concentrated in the membrane of acinar cells. Saliva flow was significantly increased by full length adiponectin (fAd or globular adiponectin (gAd perfusion in isolated rat submandibular glands. 5-Aminoimidazole-4-carboxamide-1-4-ribofuranoside (AICAR, an adenosine monophosphate activated protein kinase (AMPK activator, also increased saliva secretion. fAd, gAd, and AICAR all increased the average width of apical tight junctions in perfused submandibular glands, and decreased transepithelial electrical resistance (TER in SMG-C6 cells, suggesting that adiponectin promoted secretion by modulating paracellular permeability. fAd and gAd increased p-AMPK levels, while AraA, an AMPK antagonist, abolished fAd- and gAd-induced changes in secretion, tight junction ultrastructure, and TER. Moreover, both AdipoR1 and AdipoR2 were required for fAd- or gAd-induced p-AMPK and TER responses, suggesting from their inhibition following AdipoR1 or AdipoR2 knockdown, and co-knockdown of AdipoRs by RNA interference. Our results suggest that adiponectin functions as a promoter of salivary secretion in rat submandibular glands via activation of AdipoRs, AMPK, and paracellular permeability.

  16. Stimulation of Wnt/β-Catenin Signaling to Improve Bone Development by Naringin via Interacting with AMPK and Akt

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    Dawei Wang

    2015-07-01

    Full Text Available Background/Aims: Naringin is a naturally existing compound in citrus fruits and has been elucidated to promote bone development and maintenance. Methods: The biological roles of naringin were investigated in vitro using osteoblast-like UMR-106 cells, and in vivo through performing ovariectomy to mimic osteoporosis in female mice. Since Wnt/β-catenin signaling is involved in osteoblastogenesis, the effect of naringin on Wnt/β-catenin signaling was studied. Results: Naringin promoted the mRNA and protein expressions of β-catenin, and improved Ser552 phosphorylation on β-catenin in UMR-106 cells, which leads to the activation of lymphoid enhancer factor (LEF/ T-cell factor (TCF transcription factors. The recruitments of protein kinase B (Akt inhibitor (Akti-1/2 and AMP-activated protein kinase (AMPK inhibitor (Dorsomorphin reduced the influence of naringin on β-catenin phosphorylation, suggesting naringin activates β-catenin via regulating Akt and AMPK. In ovariectomized (OVX mice naringin treatment improved the bone strength while AMPK and Akt inhibitors partly reversed the effect, which further proved the involvements of Akt and AMPK in the action of naringin in vivo. Conclusion: Our study points to a novel finding on the mechanism of naringin in facilitating bone formation via Akt and AMPK signaling.

  17. FLCN and AMPK Confer Resistance to Hyperosmotic Stress via Remodeling of Glycogen Stores.

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    Elite Possik

    2015-10-01

    Full Text Available Mechanisms of adaptation to environmental changes in osmolarity are fundamental for cellular and organismal survival. Here we identify a novel osmotic stress resistance pathway in Caenorhabditis elegans (C. elegans, which is dependent on the metabolic master regulator 5'-AMP-activated protein kinase (AMPK and its negative regulator Folliculin (FLCN. FLCN-1 is the nematode ortholog of the tumor suppressor FLCN, responsible for the Birt-Hogg-Dubé (BHD tumor syndrome. We show that flcn-1 mutants exhibit increased resistance to hyperosmotic stress via constitutive AMPK-dependent accumulation of glycogen reserves. Upon hyperosmotic stress exposure, glycogen stores are rapidly degraded, leading to a significant accumulation of the organic osmolyte glycerol through transcriptional upregulation of glycerol-3-phosphate dehydrogenase enzymes (gpdh-1 and gpdh-2. Importantly, the hyperosmotic stress resistance in flcn-1 mutant and wild-type animals is strongly suppressed by loss of AMPK, glycogen synthase, glycogen phosphorylase, or simultaneous loss of gpdh-1 and gpdh-2 enzymes. Our studies show for the first time that animals normally exhibit AMPK-dependent glycogen stores, which can be utilized for rapid adaptation to either energy stress or hyperosmotic stress. Importantly, we show that glycogen accumulates in kidneys from mice lacking FLCN and in renal tumors from a BHD patient. Our findings suggest a dual role for glycogen, acting as a reservoir for energy supply and osmolyte production, and both processes might be supporting tumorigenesis.

  18. Regulation of phosphate transport and AMPK signal pathway by lower dietary phosphorus of broilers.

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    Miao, Zhiqiang; Feng, Yan; Zhang, Junzhen; Tian, Wenxia; Li, Jianhui; Yang, Yu

    2017-12-08

    Lower available P (aP) was used as a base value in nutritional strategies for mitigating P pollution by animal excreta. We hypothesized that the mechanism regulating phosphate transport under low dietary P might be related with the AMPK signal pathway. A total of 144 one-day-old Arbor Acres Plus broilers were randomly allocated to control (HP) or trial (LP) diets, containing 0.45 and 0.23% aP, respectively. Growth performance, blood, intestinal, and renal samples were tested in 21-day-old broilers. Results shown that LP decreased body weight gain and feed intake. Higher serum Ca and fructose, but lower serum P and insulin were detected in LP-fed broilers. NaPi-IIb mRNA expression in intestine and NaPi-IIa mRNA expression in kidney were higher in the LP group. AMP: ATP, p-AMPK: total AMPK, and p-ACC: total ACC ratios in the duodenal mucosa were decreased in the LP group, whereas the p-mTOR: total mTOR ratio increased. These findings suggested that the increase in phosphate transport owing to LP diet might be regulated either directly by higher mTOR activity or indirectly by the suppressive AMPK signal, with corresponding changes in blood insulin and fructose content. A novel viewpoint on the regulatory mechanism underlying phosphate transport under low dietary P conditions was revealed, which might provide theoretical guidelines for reducing P pollution by means of nutritional regulation.

  19. Suppression of the HSF1-mediated proteotoxic stress response by the metabolic stress sensor AMPK.

    Science.gov (United States)

    Dai, Siyuan; Tang, Zijian; Cao, Junyue; Zhou, Wei; Li, Huawen; Sampson, Stephen; Dai, Chengkai

    2015-02-03

    Numerous extrinsic and intrinsic insults trigger the HSF1-mediated proteotoxic stress response (PSR), an ancient transcriptional program that is essential to proteostasis and survival under such conditions. In contrast to its well-recognized mobilization by proteotoxic stress, little is known about how this powerful adaptive mechanism reacts to other stresses. Surprisingly, we discovered that metabolic stress suppresses the PSR. This suppression is largely mediated through the central metabolic sensor AMPK, which physically interacts with and phosphorylates HSF1 at Ser121. Through AMPK activation, metabolic stress represses HSF1, rendering cells vulnerable to proteotoxic stress. Conversely, proteotoxic stress inactivates AMPK and thereby interferes with the metabolic stress response. Importantly, metformin, a metabolic stressor and popular anti-diabetic drug, inactivates HSF1 and provokes proteotoxic stress within tumor cells, thereby impeding tumor growth. Thus, these findings uncover a novel interplay between the metabolic stress sensor AMPK and the proteotoxic stress sensor HSF1 that profoundly impacts stress resistance, proteostasis, and malignant growth. © 2014 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

  20. Reduction of food intake by fenofibrate is associated with cholecystokinin release in long-evanstokushima rats

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    S Yu Vorotnikova

    2012-09-01

    Full Text Available Реферат по статье: Reduction of food intake by fenofibrate is associated with cholecystokinin release in long-evanstokushima rats Park MK, Han Y, Kim MS, Seo E, Kang S, Park SY, Koh H, Kim DK, Lee HJ. Korean J Physiol Pharmacol Vol 16: 181-186, June, 2012

  1. TCF7L2 polymorphisms and inflammatory markers before and after treatment with fenofibrate

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    Kabagambe Edmond K

    2009-10-01

    Full Text Available Abstract Background Inflammation is implicated in causing diabetes. We tested whether transcription factor 7 like-2 (TCF7L2 gene polymorphisms (rs12255372 and rs7903146, consistently associated with type 2 diabetes, are associated with plasma concentrations of inflammatory markers before and after three weeks of daily treatment with fenofibrate. Methods Men and women in the Genetics of Lipid-Lowering Drugs and Diet Network study (n = 1025, age 49 ± 16 y were included. All participants suspended use of lipid-lowering drugs for three weeks and were then given 160 mg/day of fenofibrate for three weeks. Inflammatory markers and lipids were measured before and after fenofibrate. ANOVA was used to test for differences across TCF7L2 genotypes. Results Under the additive or dominant model, there were no significant differences (P > 0.05 in the concentrations of inflammatory markers (hsCRP, IL-2, IL-6, TNF-α and MCP-1 across TCF7L2 genotypes in the period before or after treatment. For both rs12255372 and rs7903146, homozygote T-allele carriers had significantly higher (P Conclusion Overall these data show no association between TCF7L2 polymorphisms and the inflammatory markers suggesting that the effects of TCF7L2 on diabetes may not be via inflammation.

  2. Simultaneous determination of atorvastatin calcium, ezetimibe, and fenofibrate in a tablet formulation by HPLC.

    Science.gov (United States)

    Patel, Archita; Macwana, Chhaya; Parmar, Vishal; Patel, Samir

    2012-01-01

    An accurate, simple, reproducible, and sensitive HPLC method was developed and validated for the simultaneous determination of atorvastatin calcium, ezetimibe, and fenofibrate in a tablet formulation. The analyses were performed on an RP C18 column, 150 x 4.60 mm id, 5 pm particle size. The mobile phase methanol-acetonitrile-water (76 + 13 + 11, v/v/v), was pumped at a constant flow rate of 1 mL/min. UV detection was performed at 253 nm. Retention times of atorvastatin calcium, ezetimibe, and fenofibrate were found to be 2.25, 3.68, and 6.41 min, respectively. The method was validated in terms of linearity, precision, accuracy, LOD, LOQ, and robustness. The response was linear in the range 2-10 microg/mL (r2 = 0.998) for atorvastatin calcium, 2-10 microg/mL (r2 = 0.998) for ezetimibe, and 40-120 microg/mL (r2 = 0.998) for fenofibrate. The developed method can be used for routine quality analysis of the drugs in the tablet formulation.

  3. Compound C inhibits macrophage chemotaxis through an AMPK-independent mechanism

    International Nuclear Information System (INIS)

    Lee, Youngyi; Park, Byung-Hyun; Bae, Eun Ju

    2016-01-01

    Macrophage infiltration in adipose tissue is a well-established cause of obesity-linked insulin resistance. AMP-activated protein kinase (AMPK) activation in peripheral tissues such as adipose tissue has beneficial effects on the protection against obesity-induced insulin resistance, which is mainly mediated by prevention of adipose tissue macrophage infiltration and inflammation. In examining the role of AMPK on adipose tissue inflammation, we unexpectedly found that compound C (CC), despite its inhibition of AMPK, robustly inhibited macrophage chemotaxis in RAW 264.7 cells when adipocyte conditioned medium (CM) was used as a chemoattractant. Here, we report that CC inhibition of macrophage migration occurred independently of AMPK. Mechanistically, this inhibitory effect of cell migration by CC was mediated by inhibition of the focal adhesion kinase, AKT, nuclear factor κB pathways. Moreover, the expression of chemokine monocyte chemoattractant protein-1 and pro-inflammatory genes such as tumor necrosis factor α and inducible nitric oxide synthase were prevented by CC treatment in RAW 264.7 cells stimulated with either adipocyte CM or lipopolysaccharide. Lastly, in accord with the findings of the anti-inflammatory effect of CC, we demonstrated that CC functioned as a repressor of macrophage CM-mediated insulin resistance in adipocytes. Taken together, our results suggest that CC serves as a useful inhibitory molecule against macrophage chemotaxis into adipose tissue and thus might have therapeutic potential for the treatment of obesity-linked adipose inflammation. - Highlights: • Compound C (CC) inhibits macrophage chemotaxis regardless of AMPK suppression. • CC enhances insulin sensitivity in adipocytes. • CC inhibits focal adhesion kinase, AKT, and NF-κB signaling in RAW 264.7 cells.

  4. Compound C inhibits macrophage chemotaxis through an AMPK-independent mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngyi [College of Pharmacy, Woosuk University, Wanju, Jeonbuk 55338 (Korea, Republic of); Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Jeonbuk 54896 (Korea, Republic of); Park, Byung-Hyun, E-mail: bhpark@jbnu.ac.kr [Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Jeonbuk 54896 (Korea, Republic of); Bae, Eun Ju, E-mail: ejbae@woosuk.ac.kr [College of Pharmacy, Woosuk University, Wanju, Jeonbuk 55338 (Korea, Republic of)

    2016-01-15

    Macrophage infiltration in adipose tissue is a well-established cause of obesity-linked insulin resistance. AMP-activated protein kinase (AMPK) activation in peripheral tissues such as adipose tissue has beneficial effects on the protection against obesity-induced insulin resistance, which is mainly mediated by prevention of adipose tissue macrophage infiltration and inflammation. In examining the role of AMPK on adipose tissue inflammation, we unexpectedly found that compound C (CC), despite its inhibition of AMPK, robustly inhibited macrophage chemotaxis in RAW 264.7 cells when adipocyte conditioned medium (CM) was used as a chemoattractant. Here, we report that CC inhibition of macrophage migration occurred independently of AMPK. Mechanistically, this inhibitory effect of cell migration by CC was mediated by inhibition of the focal adhesion kinase, AKT, nuclear factor κB pathways. Moreover, the expression of chemokine monocyte chemoattractant protein-1 and pro-inflammatory genes such as tumor necrosis factor α and inducible nitric oxide synthase were prevented by CC treatment in RAW 264.7 cells stimulated with either adipocyte CM or lipopolysaccharide. Lastly, in accord with the findings of the anti-inflammatory effect of CC, we demonstrated that CC functioned as a repressor of macrophage CM-mediated insulin resistance in adipocytes. Taken together, our results suggest that CC serves as a useful inhibitory molecule against macrophage chemotaxis into adipose tissue and thus might have therapeutic potential for the treatment of obesity-linked adipose inflammation. - Highlights: • Compound C (CC) inhibits macrophage chemotaxis regardless of AMPK suppression. • CC enhances insulin sensitivity in adipocytes. • CC inhibits focal adhesion kinase, AKT, and NF-κB signaling in RAW 264.7 cells.

  5. Intact regulation of the AMPK signaling network in response to exercise and insulin in skeletal muscle of male patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Kjøbsted, Rasmus; Pedersen, Andreas J T; Hingst, Janne R

    2016-01-01

    Current evidence on exercise-mediated AMPK regulation in skeletal muscle of type 2 diabetic (T2D) patients is inconclusive. This may relate to inadequate segregation of trimer complexes in the investigation of AMPK activity. We examined the regulation of AMPK and downstream targets ACCβ, TBC1D1...... and TBC1D4 in muscle biopsies obtained from thirteen overweight/obese T2D and fourteen weight-matched control male subjects before, immediately after and 3 h after exercise. Exercise increased AMPK α2β2γ3 activity and phosphorylation of ACCβ Ser(221), TBC1D1 Ser(237)/Thr(596) and TBC1D4 Ser(704......). Conversely, exercise decreased AMPK α1β2γ1 activity and TBC1D4 Ser(318)/Thr(642) phosphorylation. Interestingly, compared to pre-exercise, 3 h into exercise recovery AMPK α2β2γ1 and α1β2γ1 activity were increased concomitant with increased TBC1D4 Ser(318)/Ser(341)/Ser(704) phosphorylation. No differences...

  6. Alleviation of senescence and epithelial-mesenchymal transition in aging kidney by short-term caloric restriction and caloric restriction mimetics via modulation of AMPK/mTOR signaling.

    Science.gov (United States)

    Dong, Dan; Cai, Guang-Yan; Ning, Yi-Chun; Wang, Jing-Chao; Lv, Yang; Hong, Quan; Cui, Shao-Yuan; Fu, Bo; Guo, Ya-Nan; Chen, Xiang-Mei

    2017-03-07

    Renal fibrosis contributes to declining renal function in the elderly. What is unclear however, is whether epithelial-mesenchymal transition (EMT) contributes to this age-related renal fibrosis. Here, we analyzed indicators of EMT during kidney aging and investigated the protective effects and mechanisms of short-term regimens of caloric restriction (CR) or caloric restriction mimetics (CRMs), including resveratrol and metformin. High glucose was used to induce premature senescence and EMT in human primary proximal tubular cells (PTCs) in vitro. To test the role of AMPK-mTOR signaling, siRNA was used to deplete AMPK. Cellular senescence and AMPK-mTOR signaling markers associated with EMT were detected. CR or CRMs treatment alleviated age-related EMT in aging kidneys, which was accompanied by activation of AMPK-mTOR signaling. High glucose induced premature senescence and EMT in PTCs in vitro, which was accompanied by down-regulation of AMPK/mTOR signaling. CRMs alleviated high glucose-induced senescence and EMT via stimulation of AMPK/mTOR signaling. Activation of AMPK/mTOR signaling protected PTCs from high glucose-induced EMT and cellular senescence. Short-term regimens of CR and CRMs alleviated age-related EMT via AMPK-mTOR signaling, suggesting a potential approach to reducing renal fibrosis during aging.

  7. Enhanced oral bioavailability of fenofibrate using polymeric nanoparticulated systems: physicochemical characterization and in vivo investigation

    Directory of Open Access Journals (Sweden)

    Yousaf AM

    2015-03-01

    Full Text Available Abid Mehmood Yousaf,1 Dong Wuk Kim,1 Yu-Kyoung Oh,2 Chul Soon Yong,3 Jong Oh Kim,3 Han-Gon Choi11College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, 2College of Pharmacy, Seoul National University, Seoul, 3College of Pharmacy, Yeungnam University, Gyongsan, South KoreaBackground: The intention of this research was to prepare and compare various solubility-enhancing nanoparticulated systems in order to select a nanoparticulated formulation with the most improved oral bioavailability of poorly water-soluble fenofibrate.Methods: The most appropriate excipients for different nanoparticulated preparations were selected by determining the drug solubility in 1% (w/v aqueous solutions of each carrier. The polyvinylpyrrolidone (PVP nanospheres, hydroxypropyl-β-cyclodextrin (HP-β-CD nanocorpuscles, and gelatin nanocapsules were formulated as fenofibrate/PVP/sodium lauryl sulfate (SLS, fenofibrate/HP-β-CD, and fenofibrate/gelatin at the optimized weight ratios of 2.5:4.5:1, 1:4, and 1:8, respectively. The three solid-state products were achieved using the solvent-evaporation method through the spray-drying technique. The physicochemical characterization of these nanoparticles was accomplished by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Their physicochemical properties, aqueous solubility, dissolution rate, and pharmacokinetics in rats were investigated in comparison with the drug powder.Results: Among the tested carriers, PVP, HP-β-CD, gelatin, and SLS showed better solubility and were selected as the most appropriate constituents for various nanoparticulated systems. All of the formulations significantly improved the aqueous solubility, dissolution rate, and oral bioavailability of fenofibrate compared to the drug powder. The drug was present in the amorphous form in HP-β-CD nanocorpuscles; however, in

  8. Development and Validation of RP-HPLC Method for Simultaneous Estimation of Atorvastatin Calcium and Fenofibrate in Tablet Dosage Forms.

    Science.gov (United States)

    Jain, N; Raghuwanshi, R; Jain, Deeti

    2008-01-01

    A reverse phase high performance liquid chromatographic method was developed for the simultaneous estimation of atorvastatin calcium and fenofibrate in tablet formulation. The separation was achieved by Luna C18 column and methanol:acetate buffer pH 3.7 (82:18 v/v) as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 248 nm. Retention time of atorvastatin calcium and fenofibrate was found to be 3.02+0.1 and 9.05+0.2 min, respectively. The method has been validated for linearity, accuracy and precision. Linearity for atorvastatin calcium and Fenofibrate were in the range of 1-5 mug/ml and 16-80 mug/ml, respectively. The mean recoveries obtained for Atorvastatin calcium and fenofibrate were 101.76% and 100.06%, respectively. Developed method was found to be accurate, precise, selective and rapid for simultaneous estimation of atorvastatin calcium and fenofibrate in tablets.

  9. Shear Stress Induces Phenotypic Modulation of Vascular Smooth Muscle Cells via AMPK/mTOR/ULK1-Mediated Autophagy.

    Science.gov (United States)

    Sun, Liqian; Zhao, Manman; Liu, Aihua; Lv, Ming; Zhang, Jingbo; Li, Youxiang; Yang, Xinjian; Wu, Zhongxue

    2018-03-01

    Phenotypic modulation of vascular smooth muscle cells (VSMCs) is involved in the pathophysiological processes of the intracranial aneurysms (IAs). Although shear stress has been implicated in the proliferation, migration, and phenotypic conversion of VSMCs, the molecular mechanisms underlying these events are currently unknown. In this study, we investigated whether shear stress(SS)-induced VSMC phenotypic modulation was mediated by autophagy involved in adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) pathway. The results show that shear stress could inhibit the expression of key VSMC contractile genes and induce pro-inflammatory/matrix-remodeling genes levels, contributing to VSMCs phenotypic switching from a contractile to a synthetic phenotype. More importantly, Shear stress also markedly increased the levels of the autophagy marker microtubule-associated protein light chain 3-II (LC3II), Beclin-1, and p62 degradation. The autophagy inhibitor 3-methyladenine (3-MA) significantly blocked shear-induced phenotypic modulation of VSMCs. To further explore the molecular mechanism involved in shear-induced autophagy, we found that shear stress could activate AMPK/mTOR/ULK1 signaling pathway in VSMCs. Compound C, a pharmacological inhibitor of AMPK, significantly reduced the levels of p-AMPK and p-ULK, enhanced p-mTOR level, and finally decreased LC3II and Beclin-1 level, which suggested that activated AMPK/mTOR/ULK1 signaling was related to shear-mediated autophagy. These results indicate that shear stress promotes VSMC phenotypic modulation through the induction of autophagy involved in activating the AMPK/mTOR/ULK1 pathway.

  10. Peroxisome proliferator-activated receptor α activation induces hepatic steatosis, suggesting an adverse effect.

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    Fang Yan

    Full Text Available Non-alcoholic fatty liver disease (NAFLD is characterized by hepatic triglyceride accumulation, ranging from steatosis to steatohepatitis and cirrhosis. NAFLD is a risk factor for cardiovascular diseases and is associated with metabolic syndrome. Antihyperlipidemic drugs are recommended as part of the treatment for NAFLD patients. Although fibrates activate peroxisome proliferator-activated receptor α (PPARα, leading to the reduction of serum triglyceride levels, the effects of these drugs on NAFLD remain controversial. Clinical studies have reported that PPARα activation does not improve hepatic steatosis. In the present study, we focused on exploring the effect and mechanism of PPARα activation on hepatic triglyceride accumulation and hepatic steatosis. Male C57BL/6J mice, Pparα-null mice and HepG2 cells were treated with fenofibrate, one of the most commonly used fibrate drugs. Both low and high doses of fenofibrate were administered. Hepatic steatosis was detected through oil red O staining and electron microscopy. Notably, in fenofibrate-treated mice, the serum triglyceride levels were reduced and the hepatic triglyceride content was increased in a dose-dependent manner. Oil red O staining of liver sections demonstrated that fenofibrate-fed mice accumulated abundant neutral lipids. Fenofibrate also increased the intracellular triglyceride content in HepG2 cells. The expression of sterol regulatory element-binding protein 1c (SREBP-1c and the key genes associated with lipogenesis were increased in fenofibrate-treated mouse livers and HepG2 cells in a dose-dependent manner. However, the effect was strongly impaired in Pparα-null mice treated with fenofibrate. Fenofibrate treatment induced mature SREBP-1c expression via the direct binding of PPARα to the DR1 motif of the SREBP-1c gene. Taken together, these findings indicate the molecular mechanism by which PPARα activation increases liver triglyceride accumulation and suggest an

  11. Genetic impairment of AMPK{alpha}2 signaling does not reduce muscle glucose uptake during treadmill exercise in mice

    DEFF Research Database (Denmark)

    Maarbjerg, Stine Just; Jørgensen, Sebastian Beck; Rose, Adam John

    2009-01-01

    Some studies suggest that the 5'-AMP-activated protein kinase (AMPK) is important in regulating muscle glucose uptake in response to intense electrically stimulated contractions. However, it is unknown if AMPK regulates muscle glucose uptake during in vivo exercise. We studied this in male and fe...... signaling is not essential in regulating glucose uptake in mouse skeletal muscle during treadmill exercise and that other unknown mechanisms play a central role. Key words: exercise, glucose uptake, AMPK.......-KD mouse. Muscle glucose clearance was measured using [3H]-2-deoxy-glucose as tracer. In wildtype mice glucose clearance was increased at 30% and 70% of maximal running speed by 40% and 350% in the quadriceps muscle, and by 120% and 380% in gastrocnemius muscle, respectively. Glucose clearance...

  12. Kolliphor surfactants affect solubilization and bioavailability of fenofibrate. Studies of in vitro digestion and absorption in rats

    DEFF Research Database (Denmark)

    Berthelsen, Ragna; Holm, Rene; Jacobsen, Jette

    2015-01-01

    Selection of excipients for drug formulations requires both intellectual and experimental considerations as many of the used excipients are affected by physiological factors, e.g., they may be digested by pancreatic enzymes in the gastrointestinal tract. In the present paper we have looked...... formulations only comprised an aqueous micellar solution of the model drug (fenofibrate) in varying concentrations (2–25% (w/v)) of the three tested surfactants. Increased concentrations of Kolliphor ELP and EL led to increased fenofibrate AUC0–24h values. For the Kolliphor RH40 formulations, an apparent...... choice for solubilizing fenofibrate in order to increase the absorption upon oral administration. Due to drug dependent effects of the different types of Kolliphor, more studies are recommended in order to understand which type of Kolliphor is best suited for a given drug....

  13. The effect of an intracerebroventricular injection of metformin or AICAR on the plasma concentrations of melatonin in the ewe: potential involvement of AMPK?

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    Collet Armelle

    2011-07-01

    Full Text Available Abstract Background It is now widely accepted that AMP-activated protein kinase (AMPK is a critical regulator of energy homeostasis. Recently, it has been shown to regulate circadian clocks. In seasonal breeding species such as sheep, the circadian clock controls the secretion of an endogenous rhythm of melatonin and, as a consequence, is probably involved in the generation of seasonal rhythms of reproduction. Considering this, we identified the presence of the subunits of AMPK in different hypothalamic nuclei involved in the pre- and post-pineal pathways that control seasonality of reproduction in the ewe and we investigated if the intracerebroventricular (i.c.v. injection of two activators of AMPK, metformin and AICAR, affected the circadian rhythm of melatonin in ewes that were housed in constant darkness. In parallel the secretion of insulin was monitored as a peripheral metabolic marker. We also investigated the effects of i.c.v. AICAR on the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC, a downstream target of AMPK, in brain structures along the photoneuroendocrine pathway to the pineal gland. Results All the subunits of AMPK that we studied were identified in all brain areas that were dissected but with some differences in their level of expression among structures. Metformin and AICAR both reduced (p Conclusions Taken together, these results suggest a potential role for AMPK on the secretion of melatonin probably acting trough the paraventricular nucleus and/or directly in the pineal gland. We conclude that AMPK may act as a metabolic cue to modulate the rhythm of melatonin secretion.

  14. Targeting AMPK, mTOR and β-Catenin by Combined Metformin and Aspirin Therapy in HCC: An Appraisal in Egyptian HCC Patients.

    Science.gov (United States)

    Abdelmonsif, Doaa Ali; Sultan, Ahmed S; El-Hadidy, Wessam F; Abdallah, Dina Mohamed

    2018-02-01

    Hepatocellular carcinoma (HCC) is an expanding health problem with a great impact on morbidity and mortality, both in Egypt and worldwide. Recently, metformin and aspirin showed a potential anticancer effect on HCC, although the mechanism of this effect is not fully elucidated. The current work aimed to investigate the possibility of targeting AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and β-catenin proteins through combined metformin/aspirin treatment in the HepG2 cell line, and to explore such molecular targets in Egyptian HCC patients. HepG2 cells were exposed to increasing concentrations of metformin, aspirin and combined treatment, and an MTT assay was performed to determine half maximal inhibitory concentration (IC 50 ). Caspase-3 activity, cell cycle analysis, and protein expression of AMPK, phosphorylated AMPK (pAMPK) and mTOR proteins were assessed. Furthermore, the expression and localization of β-catenin protein was assessed by immunocytochemistry, and protein expression of pAMPK, mTOR and β-catenin was assessed in Egyptian HCC and cirrhotic tissue specimens. Metformin/aspirin combined treatment had a synergistic effect on cell cycle arrest at the G2/M phase and apoptosis induction in a caspase-dependent manner via downregulation of pAMPK and mTOR protein expression. Additionally, metformin/aspirin combined treatment enhanced cell-cell membrane localization of β-catenin expression in HepG2 cells, which might inhibit the metastatic potential of HepG2 cells. In Egyptian HCC specimens, pAMPK, mTOR and β-catenin proteins showed a significant increased expression compared with cirrhotic controls. Targeting AMPK, mTOR and β-catenin by combined metformin/aspirin treatment could be a promising therapeutic strategy for Egyptian HCC patients, and possibly other HCC patients.

  15. Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yunxia, E-mail: wwwdluyx@sina.com [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Cheng, Jingjing [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Chen, Li [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Department of Medical Laboratory, Anhui Provincial Hospital, Hefei, Anhui 230001 (China); Li, Chaofei; Chen, Guanjun [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Gui, Li [The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Shen, Bing [Department of Physiology, Anhui Medical University, Hefei, Anhui 230032 (China); Zhang, Qiu [Department of Endocrinology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022 (China)

    2015-02-27

    Fenofibrate (FF) is widely used to lower blood lipids in clinical practice, but whether its protective effect on endothelium-dependent vasodilatation (EDV) in thoracic aorta is related with endoplasmic reticulum (ER) stress remains unknown. In this study, female Sprauge Dawley rats were divided into standard chow diets (SCD), high-fat diets (HFD) and HFD plus FF treatment group (HFD + FF) randomly. The rats of latter two groups were given HFD feeding for 5 months, then HFD + FF rats were treated with FF (30 mg/kg, once daily) via gavage for another 2 months. The pathological and tensional changes, protein expression of eNOS, and ER stress related genes in thoracic aorta were measured. Then impacts of palmitic acid (PA) and FF on EDV of thoracic aorta from normal female SD rats were observed. Ultimately the expression of ER stress related genes were assessed in primary mouse aortic endothelial cells (MAEC) treated by fenofibric acid (FA) and PA. We found that FF treatment improved serum lipid levels and pathological changes in thoracic aorta, accompanied with decreased ER stress and increased phosphorylation of eNOS. FF pretreatment also improved EDV impaired by different concentrations of PA treatment. The dose- and time-dependent inhibition of cell proliferation by PA were inverted by FA pretreatment. Phosphorylation of eNOS and expression of ER stress related genes were all inverted by FA pretreatment in PA-treated MAEC. Our findings show that fenofibrate recovers damaged EDV by chronic HFD feeding and acute stimulation of PA, this effect is related with decreased ER stress and increased phosphorylation of eNOS. - Highlights: • Fenofibrate treatment improved pathological changes in thoracic aorta by chronic high-fat-diet feeding. • Fenofibrate pretreatment improved endothelium-dependent vasodilation impaired by different concentrations of palmitic acid. • The inhibition of proliferation in endothelial cells by palmitic acid were inverted by fenofibric

  16. [The fixed combination of pravastatin and fenofibrate: what can it provide?].

    Science.gov (United States)

    Díaz Rodríguez, Ángel

    2014-07-01

    The treatment of patients with high cardiovascular risk and mixed hyperlipidemia is difficult due to multiple quantitative and qualitative lipid abnormalities. The priority is to reduce LDL-c levels, for which statins are the drug of choice. Despite the benefits of statins, the residual cardiovascular risk is very high in patients with atherogenic dyslipidemia. To reduce this risk, we also need to control non-HDL cholesterol levels, decreasing triglyceride levels and increasing HDL-c levels. To achieve these objectives and lifestyle changes, the use of combined therapy is often required. Fibrates are drugs that can be used in combination with statins to reduce this residual risk. Fenofibrate is well tolerated in combination with statins. The fixed combination of pravastatin/ fenofibrate has been shown to have complementary benefits in the atherogenic lipid profile in general. The combination is well tolerated and is indicated in patients with high risk and mixed hyperlipidemia who have controlled or are close to their objectives for LDL-c levels, using 40-mg pravastatin in monotherapy. The beneficial eff ect of the combination on LDL-c levels is minimal and is primarily observed in non-HDL cholesterol, triglycerides and HDL-c. The combination of pravastatin 40 and fenofibrate 160 can provide a considerable clinical benefit to patients with high risk and mixed atherogenic dyslipidemia, to patients with LDL-c levels that are controlled or near the objectives for decreasing their residual risk of lipid origin and is especially useful for patients with type 2 diabetes, obesity and combined metabolic syndrome and familial hyperlipidemia. Copyright © 2014 Sociedad Española de Arteriosclerosis y Elsevier España, S.L. All rights reserved.

  17. Commonly used fertility drugs, a diet supplement, and stress force AMPK-dependent block of stemness and development in cultured mammalian embryos.

    Science.gov (United States)

    Bolnick, Alan; Abdulhasan, Mohammed; Kilburn, Brian; Xie, Yufen; Howard, Mindie; Andresen, Paul; Shamir, Alexandra M; Dai, Jing; Puscheck, Elizabeth E; Rappolee, Daniel A

    2016-08-01

    The purpose of the present study is to test whether metformin, aspirin, or diet supplement (DS) BioResponse-3,3'-Diindolylmethane (BR-DIM) can induce AMP-activated protein kinase (AMPK)-dependent potency loss in cultured embryos and whether metformin (Met) + Aspirin (Asa) or BR-DIM causes an AMPK-dependent decrease in embryonic development. The methods used were as follows: culture post-thaw mouse zygotes to the two-cell embryo stage and test effects after 1-h AMPK agonists' (e.g., Met, Asa, BR-DIM, control hyperosmotic stress) exposure on AMPK-dependent loss of Oct4 and/or Rex1 nuclear potency factors, confirm AMPK dependence by reversing potency loss in two-cell-stage embryos with AMPK inhibitor compound C (CC), test whether Met + Asa (i.e., co-added) or DS BR-DIM decreases development of two-cell to blastocyst stage in an AMPK-dependent (CC-sensitive) manner, and evaluate the level of Rex1 and Oct4 nuclear fluorescence in two-cell-stage embryos and rate of two-cell-stage embryo development to blastocysts. Met, Asa, BR-DIM, or hyperosmotic sorbitol stress induces rapid ~50-85 % Rex1 and/or Oct4 protein loss in two-cell embryos. This loss is ~60-90 % reversible by co-culture with AMPK inhibitor CC. Embryo development from two-cell to blastocyst stage is decreased in culture with either Met + Asa or BR-DIM, and this is either >90 or ~60 % reversible with CC, respectively. These experimental designs here showed that Met-, Asa-, BR-DIM-, or sorbitol stress-induced rapid potency loss in two-cell embryos is AMPK dependent as suggested by inhibition of Rex1 and/or Oct4 protein loss with an AMPK inhibitor. The DS BR-DIM or fertility drugs (e.g., Met + Asa) that are used to enhance maternal metabolism to support fertility can also chronically slow embryo growth and block development in an AMPK-dependent manner.

  18. AMPK promotes survival of c-Myc-positive melanoma cells by suppressing oxidative stress.

    Science.gov (United States)

    Kfoury, Alain; Armaro, Marzia; Collodet, Caterina; Sordet-Dessimoz, Jessica; Giner, Maria Pilar; Christen, Stefan; Moco, Sofia; Leleu, Marion; de Leval, Laurence; Koch, Ute; Trumpp, Andreas; Sakamoto, Kei; Beermann, Friedrich; Radtke, Freddy

    2018-03-01

    Although c-Myc is essential for melanocyte development, its role in cutaneous melanoma, the most aggressive skin cancer, is only partly understood. Here we used the Nras Q61K INK4a -/- mouse melanoma model to show that c-Myc is essential for tumor initiation, maintenance, and metastasis. c-Myc-expressing melanoma cells were preferentially found at metastatic sites, correlated with increased tumor aggressiveness and high tumor initiation potential. Abrogation of c-Myc caused apoptosis in primary murine and human melanoma cells. Mechanistically, c-Myc-positive melanoma cells activated and became dependent on the metabolic energy sensor AMP-activated protein kinase (AMPK), a metabolic checkpoint kinase that plays an important role in energy and redox homeostasis under stress conditions. AMPK pathway inhibition caused apoptosis of c-Myc-expressing melanoma cells, while AMPK activation protected against cell death of c-Myc-depleted melanoma cells through suppression of oxidative stress. Furthermore, TCGA database analysis of early-stage human melanoma samples revealed an inverse correlation between C-MYC and patient survival, suggesting that C-MYC expression levels could serve as a prognostic marker for early-stage disease. © 2018 The Authors.

  19. Calcineurin A (Ca Inhibition Supresses Protein Synthesis Via Amp Dependent Kinase (Ampk.

    Directory of Open Access Journals (Sweden)

    H. Franch

    2012-06-01

    Full Text Available Diabetes stimulates CA activity in the kidney and CA inhibitor cyclosporine A (CYA or CAβ isoform knock-out (CAβ -/- block diabetic renal hypertrophy.CA regulates the mammalian target of rapamycin (mTOR to reduce protein synthesis (PS during cardiac hypertrophy.To study this pathway, NRK-52E and SV40 transformed CAβ +/+ and -/- proximal tubule cell lines were treated with 10 nM epidermal growth factor (EGF and/or 8 μM CYA. After 48 hrs of CYA in NRK-52E cells, EGF-induced protein/well was 30±4% lower with decreased PS (49±2% rather than increased protein breakdown. In CAβ -/- cells, protein/well (20+2% and PS (16 ±1% were lower and CYA did not decrease PS further. In CAβ+/+ cells, CYA reduced PS 20+2%. However, CYA did not block mTOR signaling as measured by phosphorylation (P at S2448 or by p70S6 kinase P at T389. CYA also did not alter the mTOR dependent pathway of macroautophagy. However, CYA in NRK-52E or CAβ -/- cells showed increased activation of the metformin-sensitive energy sensor, AMPK, as measured by P of T172 by ∼5- or>10-fold, respectively. AMPK reduces PS via P of eukaryotic elongation factor 2 (eEF2 at T356 and CYA increased eEF2 P by∼3 fold.We conclude CA inhibition reduces PS in renal hypertrophy via a novel pathway involving AMPK and eEF2 rather than by mTOR and p70S6 kinase. Activation of AMPK or altered energy metabolism via CAβ may be important in CA inhibitor nephrotoxicity.

  20. Metformin induces apoptosis through AMPK-dependent inhibition of UPR signaling in ALL lymphoblasts.

    Directory of Open Access Journals (Sweden)

    Gilles M Leclerc

    Full Text Available The outcome of patients with resistant phenotypes of acute lymphoblastic leukemia (ALL or those who relapse remains poor. We investigated the mechanism of cell death induced by metformin in Bp- and T-ALL cell models and primary cells, and show that metformin effectively induces apoptosis in ALL cells. Metformin activated AMPK, down-regulated the unfolded protein response (UPR demonstrated by significant decrease in the main UPR regulator GRP78, and led to UPR-mediated cell death via up-regulation of the ER stress/UPR cell death mediators IRE1α and CHOP. Using shRNA, we demonstrate that metformin-induced apoptosis is AMPK-dependent since AMPK knock-down rescued ALL cells, which correlated with down-regulation of IRE1α and CHOP and restoration of the UPR/GRP78 function. Additionally rapamycin, a known inhibitor of mTOR-dependent protein synthesis, rescued cells from metformin-induced apoptosis and down-regulated CHOP expression. Finally, metformin induced PIM-2 kinase activity and co-treatment of ALL cells with a PIM-1/2 kinase inhibitor plus metformin synergistically increased cell death, suggesting a buffering role for PIM-2 in metformin's cytotoxicity. Similar synergism was seen with agents targeting Akt in combination with metformin, supporting our original postulate that AMPK and Akt exert opposite regulatory roles on UPR activity in ALL. Taken together, our data indicate that metformin induces ALL cell death by triggering ER and proteotoxic stress and simultaneously down-regulating the physiologic UPR response responsible for effectively buffering proteotoxic stress. Our findings provide evidence for a role of metformin in ALL therapy and support strategies targeting synthetic lethal interactions with Akt and PIM kinases as suitable for future consideration for clinical translation in ALL.

  1. Lack of Adipocyte AMPK Exacerbates Insulin Resistance and Hepatic Steatosis through Brown and Beige Adipose Tissue Function

    DEFF Research Database (Denmark)

    Mottillo, Emilio P; Desjardins, Eric M; Crane, Justin D

    2016-01-01

    Brown (BAT) and white (WAT) adipose tissues play distinct roles in maintaining whole-body energy homeostasis, and their dysfunction can contribute to non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes. The AMP-activated protein kinase (AMPK) is a cellular energy sensor, but its role in...

  2. Short-term exercise training in humans reduces AMPK signalling during prolonged exercise independent of muscle glycogen.

    Science.gov (United States)

    McConell, Glenn K; Lee-Young, Robert S; Chen, Zhi-Ping; Stepto, Nigel K; Huynh, Ngan N; Stephens, Terry J; Canny, Benedict J; Kemp, Bruce E

    2005-10-15

    We examined the effect of short-term exercise training on skeletal muscle AMP-activated protein kinase (AMPK) signalling and muscle metabolism during prolonged exercise in humans. Eight sedentary males completed 120 min of cycling at 66 +/- 1% , then exercise trained for 10 days, before repeating the exercise bout at the same absolute workload. Participants rested for 72 h before each trial while ingesting a high carbohydrate diet (HCHO). Exercise training significantly (P free AMP: ATP ratio and glucose disposal and increased fat oxidation. Exercise training abolished the 9-fold increase in AMPK alpha2 activity observed during pretraining exercise. Since training increased muscle glycogen content by 93 +/- 12% (P glycogen content was essentially matched pre- and post-training by exercise and a low CHO diet (LCHO; post-training muscle glycogen 52 +/- 7% less than in HCHO, P glycogen levels in the two studies we obtained very similar results. In both studies the increase in ACCbeta Ser(221) phosphorylation was reduced during exercise after training. In conclusion, there is little activation of AMPK signalling during prolonged exercise following short-term exercise training suggesting that other factors are important in the regulation of glucose disposal and fat oxidation under these circumstances. It appears that muscle glycogen is not an important regulator of AMPK activation during exercise in humans when exercise is begun with normal or high muscle glycogen levels.

  3. Two weeks of metformin treatment enhances mitochondrial respiration in skeletal muscle of AMPK kinase dead but not wild type mice

    DEFF Research Database (Denmark)

    Kristensen, Jonas Møller; Larsen, Steen; Helge, Jørn Wulff

    2013-01-01

    signaling. We investigated this by two weeks of oral metformin treatment of muscle specific kinase dead a(2) (KD) AMPK mice and wild type (WT) littermates. We measured mitochondrial respiration and protein activity and expressions of key enzymes involved in mitochondrial carbohydrate and fat metabolism...

  4. Polyphenol-Rich Diets Exacerbate AMPK-Mediated Autophagy, Decreasing Proliferation of Mosquito Midgut Microbiota, and Extending Vector Lifespan.

    Directory of Open Access Journals (Sweden)

    Rodrigo Dutra Nunes

    2016-10-01

    Full Text Available Mosquitoes feed on plant-derived fluids such as nectar and sap and are exposed to bioactive molecules found in this dietary source. However, the role of such molecules on mosquito vectorial capacity is unknown. Weather has been recognized as a major determinant of the spread of dengue, and plants under abiotic stress increase their production of polyphenols.Here, we show that including polyphenols in mosquito meals promoted the activation of AMP-dependent protein kinase (AMPK. AMPK positively regulated midgut autophagy leading to a decrease in bacterial proliferation and an increase in vector lifespan. Suppression of AMPK activity resulted in a 6-fold increase in midgut microbiota. Similarly, inhibition of polyphenol-induced autophagy induced an 8-fold increase in bacterial proliferation. Mosquitoes maintained on the polyphenol diet were readily infected by dengue virus.The present findings uncover a new direct route by which exacerbation of autophagy through activation of the AMPK pathway leads to a more efficient control of mosquito midgut microbiota and increases the average mosquito lifespan. Our results suggest for the first time that the polyphenol content and availability of the surrounding vegetation may increase the population of mosquitoes prone to infection with arboviruses.

  5. Polyphenol-Rich Diets Exacerbate AMPK-Mediated Autophagy, Decreasing Proliferation of Mosquito Midgut Microbiota, and Extending Vector Lifespan

    Science.gov (United States)

    Nunes, Rodrigo Dutra; Ventura-Martins, Guilherme; Moretti, Débora Monteiro; Medeiros-Castro, Priscilla; Rocha-Santos, Carlucio; Daumas-Filho, Carlos Renato de Oliveira; Bittencourt-Cunha, Paula Rego Barros; Martins-Cardoso, Karina; Cudischevitch, Cecília Oliveira; Menna-Barreto, Rubem Figueiredo Sadok; Oliveira, José Henrique Maia; Gusmão, Desiely Silva; Alves Lemos, Francisco José; Alviano, Daniela Sales; Oliveira, Pedro Lagerblad; Lowenberger, Carl; Majerowicz, David; Oliveira, Ricardo Melo; Mesquita, Rafael Dias; Atella, Georgia Correa

    2016-01-01

    Background Mosquitoes feed on plant-derived fluids such as nectar and sap and are exposed to bioactive molecules found in this dietary source. However, the role of such molecules on mosquito vectorial capacity is unknown. Weather has been recognized as a major determinant of the spread of dengue, and plants under abiotic stress increase their production of polyphenols. Results Here, we show that including polyphenols in mosquito meals promoted the activation of AMP-dependent protein kinase (AMPK). AMPK positively regulated midgut autophagy leading to a decrease in bacterial proliferation and an increase in vector lifespan. Suppression of AMPK activity resulted in a 6-fold increase in midgut microbiota. Similarly, inhibition of polyphenol-induced autophagy induced an 8-fold increase in bacterial proliferation. Mosquitoes maintained on the polyphenol diet were readily infected by dengue virus. Conclusion The present findings uncover a new direct route by which exacerbation of autophagy through activation of the AMPK pathway leads to a more efficient control of mosquito midgut microbiota and increases the average mosquito lifespan. Our results suggest for the first time that the polyphenol content and availability of the surrounding vegetation may increase the population of mosquitoes prone to infection with arboviruses. PMID:27732590

  6. Cocoa flavonoids improve insulin signalling and modulate glucose production via AKT and AMPK in HepG2 cells.

    Science.gov (United States)

    Cordero-Herrera, Isabel; Martín, María Angeles; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2013-06-01

    Cocoa and (-)-epicatechin (EC), a main cocoa flavanol, have been suggested to exert beneficial effects in diabetes, but the mechanism for their insulin-like effects remains unknown. In this study, the modulation of insulin signalling by EC and a cocoa phenolic extract (CPE) on hepatic HepG2 cells was investigated by analysing key proteins of the insulin pathways, namely insulin receptor, insulin receptor substrate (IRS) 1 and 2, PI3K/AKT and 5'-AMP-activated protein kinase (AMPK), as well as the levels of the glucose transporter GLUT-2 and the hepatic glucose production. EC and CPE enhanced the tyrosine phosphorylation and total insulin receptor, IRS-1 and IRS-2 levels and activated the PI3K/AKT pathway and AMPK in HepG2 cells. CPE also enhanced the levels of GLUT-2. Interestingly, EC and CPE modulated the expression of phosphoenolpyruvate carboxykinase, a key protein involved in the gluconeogenesis, leading to a diminished glucose production. In addition, EC- and CPE-regulated hepatic gluconeogenesis was prevented by the blockage of AKT and AMPK. Our data suggest that EC and CPE strengthen the insulin signalling by activating key proteins of that pathway and regulating glucose production through AKT and AMPK modulation in HepG2 cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. EPA blocks TNF-α-induced inhibition of sugar uptake in Caco-2 cells via GPR120 and AMPK.

    Science.gov (United States)

    Castilla-Madrigal, Rosa; Barrenetxe, Jaione; Moreno-Aliaga, María J; Lostao, María Pilar

    2018-03-01

    The aim of the present work was to investigate in Caco-2 cells whether eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, could block the inhibitory effect of tumor necrosis factor-α (TNF-α) on sugar transport, and identify the intracellular signaling pathways involved. After pre-incubation of the Caco-2 cells with TNF-α and EPA for 1 hr, EPA prevented the inhibitory effect of the cytokine on α-methyl-d-glucose (αMG) uptake (15 min) and on SGLT1 expression at the brush border membrane, measured by Western blot. The ERK1/2 inhibitor PD98059 and the AMPK activator AICAR also prevented the inhibitory effect of TNF-α on both αMG uptake and SGLT1 expression. Interestingly, the AMPK inhibitor, Compound C, abolished the ability of EPA to prevent TNF-α-induced reduction of sugar uptake and transporter expression. The GPR120 antagonist, AH7614, also blocked the preventive effect of EPA on TNF-α-induced decrease of αMG uptake and AMPK phosphorylation. In summary, TNF-α inhibits αMG uptake by decreasing SGLT1 expression in the brush border membrane through the activation of ERK1/2 pathway. EPA prevents the inhibitory effect of TNF-α through the involvement of GPR120 and AMPK activation. © 2017 Wiley Periodicals, Inc.

  8. Deoxypodophyllotoxin suppresses tumor vasculature in HUVECs by promoting cytoskeleton remodeling through LKB1-AMPK dependent Rho A activatio.

    Science.gov (United States)

    Wang, Yurong; Wang, Bin; Guerram, Mounia; Sun, Li; Shi, Wei; Tian, Chongchong; Zhu, Xiong; Jiang, Zhenzhou; Zhang, Luyong

    2015-10-06

    Angiogenesis plays a critical role in the growth and metastasis of tumors, which makes it an attractive target for anti-tumor drug development. Deoxypodophyllotoxin (DPT), a natural product isolated from Anthriscus sylvestris, inhibits cell proliferation and migration in various cancer cell types. Our previous studies indicate that DPT possesses both anti-angiogenic and vascular-disrupting activities. Although the RhoA/ RhoA kinase (ROCK) signaling pathway is implicated in DPT-stimulated cytoskeleton remodeling and tumor vasculature suppressing, the detailed mechanisms by which DPT mediates these effects are poorly understood. In the current study, we found that DPT promotes cytoskeleton remodeling in human umbilical vein endothelial cells (HUVECs) via stimulation of AMP-activated protein kinase (AMPK) and that this effect is abolished by either treatment with a selective AMPK inhibitor or knockdown. Moreover, the cellular levels of LKB1, a kinase upstream of AMPK, were enhanced following DPT exposure. DPT-induced activation of AMPK in tumor vasculature effect was also verified by transgenic zebrafish (VEGFR2:GFP), Matrigel plug assay, and xenograft model in nude mice. The present findings may lay the groundwork for a novel therapeutic approach in treating cancer.

  9. Chloroquine increases phosphorylation of AMPK and Akt in myotubes

    Directory of Open Access Journals (Sweden)

    Larry D. Spears

    2016-03-01

    Significance: These ATM-independent effects of chloroquine on AMPK and Akt and the additional effect to decrease intracellular calcium are likely to partially underlie the positive metabolic effects of chloroquine that have been reported in the literature.

  10. [Indications for the combination of pravastatin and fenofibrate according to the type of dyslipidemia].

    Science.gov (United States)

    Núñez-Cortés, Jesús Millán

    2014-07-01

    The combination with fixed doses of pravastatin (40 mg) and fenofibrate (160 mg) offers a therapeutic alternative, especially in the comprehensive approach to mixed hyperlipidemia in patients with high cardiovascular risk of metabolic origin. It also ensures the efficacy and safety as a result of the evidence that supports the clinical benefit of both pravastatin in primary and secondary prevention and fenofibrate in patients with atherogenic dyslipidemia. This combination also has few adverse effects, which are similar in all cases to those produced by the isolated monotherapy of each of the drugs. Consequently, the possible indications for this combination include patients with mixed hyperlipidemia, patients with atherogenic dyslipidemia (increased triglyceride levels, reduced HDL-c levels and moderately increased LDL-c levels), patients with hypertriglyceridemia who need to reduce their LDL-c levels, patients with low HDL syndrome who also require a reduction in LDL-c levels, patients with moderate hypercholesterolemia who require an additional reduction of triglyceride levels and especially patients with high atherogenic metabolic risk who require an overall intervention for each of the lipid fractions. Copyright © 2014 Sociedad Española de Arteriosclerosis y Elsevier España, S.L. All rights reserved.

  11. Hyperlipidemia related to the use of HIV-protease inhibitors: natural history and results of treatment with fenofibrate

    Directory of Open Access Journals (Sweden)

    Bruno Caramelli

    Full Text Available Hyperlipidemia has been frequently recorded as a side effect of treating HIV patients with protease inhibitors (PI. This study was initiated to analyze the modifications on blood lipids in HIV-patients receiving PI and the safety and efficacy of the treatment with fenofibrate. Total (TC and HDL-cholesterol, triglycerides (TG, and CD4+ T-cell counts were measured in 30 HAART-naive patients (Group I before and after PI introduction. In a second phase of the study, the effects of fenofibrate on lipids, CPK, CD4+, and viral load were determined in 13 patients (Group II with elevated TC or TG. In Group I, 60% of the patients showed TC or TG elevations. Average increments of 31% and 146% in TC and TG respectively (p<0.0006 and p<0.0001 were observed. In Group II, fenofibrate treatment was associated with decrements of 6.6% (TC and 45.7% (TG (p=0.07 and 0.0002 and no modifications on CPK, CD4+, and viral load. In conclusion, hyperlipidemia is common during the treatment of HIV with protease inhibitors, and fenofibrate appears to be an effective and safe choice for its treatment.

  12. Hyperlipidemia related to the use of HIV-protease inhibitors: natural history and results of treatment with fenofibrate

    Directory of Open Access Journals (Sweden)

    Caramelli Bruno

    2001-01-01

    Full Text Available Hyperlipidemia has been frequently recorded as a side effect of treating HIV patients with protease inhibitors (PI. This study was initiated to analyze the modifications on blood lipids in HIV-patients receiving PI and the safety and efficacy of the treatment with fenofibrate. Total (TC and HDL-cholesterol, triglycerides (TG, and CD4+ T-cell counts were measured in 30 HAART-naive patients (Group I before and after PI introduction. In a second phase of the study, the effects of fenofibrate on lipids, CPK, CD4+, and viral load were determined in 13 patients (Group II with elevated TC or TG. In Group I, 60% of the patients showed TC or TG elevations. Average increments of 31% and 146% in TC and TG respectively (p<0.0006 and p<0.0001 were observed. In Group II, fenofibrate treatment was associated with decrements of 6.6% (TC and 45.7% (TG (p=0.07 and 0.0002 and no modifications on CPK, CD4+, and viral load. In conclusion, hyperlipidemia is common during the treatment of HIV with protease inhibitors, and fenofibrate appears to be an effective and safe choice for its treatment.

  13. Association of gene variants with lipid levels in response to fenofibrate is influenced by metabolic syndrome status

    Science.gov (United States)

    Fenofibrate therapy reduces serum triglycerides (TG) and increases high-density lipoprotein-cholesterol (HDL-C) and thus addresses the atherogenic dyslipidemia associated with metabolic syndrome (MetS). Our hypothesis is that genetic factors contribute to the variability of lipid response to fenofib...

  14. Antroquinonol displays anticancer potential against human hepatocellular carcinoma cells: a crucial role of AMPK and mTOR pathways.

    Science.gov (United States)

    Chiang, Po-Cheng; Lin, Ssu-Chia; Pan, Shiow-Lin; Kuo, Ching-Hua; Tsai, I-Lin; Kuo, Mao-Tien; Wen, Wu-Che; Chen, Peini; Guh, Jih-Hwa

    2010-01-15

    5'AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR) are two serine/threonine protein kinases responsible for cellular energy homeostasis and translational control, respectively. Evidence suggests that these two kniases are potential targets for cancer chemotherapy against hepatocellular carcinoma (HCC). Antroquinonol that is isolated from Antrodia camphorate, a well-known Traditional Chinese Medicine for treatment of liver diseases, displayed effective anticancer activity against both HBV DNA-positive and -negative HCC cell lines. The rank order of potency against HCCs is HepG2>HepG2.2.15>Mahlavu>PLC/PRF/5>SK-Hep1>Hep3B. Antroquinonol completely abolished cell-cycle progression released from double-thymidine-block synchronization and caused a subsequent apoptosis. The data were supported by down-regulation and reduced nuclear translocation of G1-regulator proteins, including cyclin D1, cyclin E, Cdk4 and Cdk2. Further analysis showed that the mRNA expressions of the G1-regulator proteins were not modified by antroquinonol, indicating an inhibition of translational but not transcriptional levels. Antroquinonol induced the assembly of tuberous sclerosis complex (TSC)-1/TSC2, leading to the blockade of cellular protein synthesis through inhibition of protein phosphorylation including mTOR (Ser(2448)), p70(S6K) (Thr(421)/Ser(424) and Thr(389)) and 4E-BP1 (Thr(37)/Thr(46) and Thr(70)). Furthermore, the AMPK activity was elevated by antroquinonol. Compound C, a selective AMPK inhibitor, significantly reversed antroquinonol-mediated effects suggesting the crucial role of AMPK. Besides, the loss of mitochondrial membrane potential and depletion of mitochondrial content indicated the mitochondrial stress caused by antroquinonol. In summary, the data suggest that antroquinonol displays anticancer activity against HCCs through AMPK activation and inhibition of mTOR translational pathway, leading to G1 arrest of the cell-cycle and subsequent cell

  15. Secoisolariciresinol diglucoside inhibits adipogenesis through the AMPK pathway.

    Science.gov (United States)

    Kang, JongWook; Park, Jinbong; Kim, Hye-Lin; Jung, Yunu; Youn, Dong-Hyun; Lim, Seona; Song, Gahee; Park, Hyewon; Jin, Jong Sik; Kwak, Hyun Jeong; Um, Jae-Young

    2018-02-05

    Flaxseeds are used to treat metabolic diseases such as type 2 diabetes, fatty liver, hyperlipidemia and obesity. Secoisolariciresinol diglucoside (SDG) is a main substance of lignan which belongs to the phytoestrogen family and exists abundantly in flaxseeds. In this study, SDG reduced the body weight and size of adipose tissue, and decreased protein expressions of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding protein α (C/EBPα) in the high fat diet-fed-induced obese mice model. In the vitro study, we examined the anti-adipogenic effect of SDG during differentiation of 3T3-L1 cells into adipocytes. 3T3-L1 preadipocytes were differentiated and treated with various concentrations of SDG. Oil Red O staining was done to measure the quantity of lipid contents. As a result, SDG reduced lipid accumulation and decreased the expressions of adipogenic-related genes such as adipocyte fatty-acid-binding protein 2, adiponectin, and resistin. SDG also decreased the mRNA and protein levels of PPARγ and C/EBPα. Furthermore, phosphorylation levels of AMP-activated protein kinase α (AMPK α) and its upstream activator, liver kinase B1, were significantly increased by SDG in 3T3-L1 cells. These results suggest that SDG inhibits adipogenesis by activating AMPKα, suggesting it could be an attractive therapeutic candidate for the treatment of obesity. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Blocking a vicious cycle nNOS/peroxynitrite/AMPK by S-nitrosoglutathione: implication for stroke therapy.

    Science.gov (United States)

    Khan, Mushfiquddin; Dhammu, Tajinder S; Matsuda, Fumiyo; Singh, Avtar K; Singh, Inderjit

    2015-07-15

    Stroke immediately sets into motion sustained excitotoxicity and calcium dysregulation, causing aberrant activity in neuronal nitric oxide synthase (nNOS) and an imbalance in the levels of nitric oxide (NO). Drugs targeting nNOS-originated toxicity may therefore reduce stroke-induced damage. Recently, we observed that a redox-modulating agent of the NO metabolome, S-nitrosoglutathione (GSNO), confers neurovascular protection by reducing the levels of peroxynitrite, a product of aberrant NOS activity. We therefore investigated whether GSNO-mediated neuroprotection and improved neurological functions depend on blocking nNOS/peroxynitrite-associated injurious mechanisms using a rat model of cerebral ischemia reperfusion (IR). IR increased the activity of nNOS, the levels of neuronal peroxynitrite and phosphorylation at Ser(1412) of nNOS. GSNO treatment of IR animals decreased IR-activated nNOS activity and neuronal peroxynitrite levels by reducing nNOS phosphorylation at Ser(1412). The Ser(1412) phosphorylation is associated with increased nNOS activity. Supporting the notion that nNOS activity and peroxynitrite are deleterious following IR, inhibition of nNOS by its inhibitor 7-nitroindazole or reducing peroxynitrite by its scavenger FeTPPS decreased IR injury. GSNO also decreased the activation of AMP Kinase (AMPK) and its upstream kinase LKB1, both of which were activated in IR brain. AMPK has been implicated in nNOS activation via Ser(1412) phosphorylation. To determine whether AMPK activation is deleterious in the acute phase of IR, we treated animals after IR with AICAR (an AMPK activator) and compound c (an AMPK inhibitor). While AICAR potentiated, compound c reduced the IR injury. Taken together, these results indicate an injurious nNOS/peroxynitrite/AMPK cycle following stroke, and GSNO treatment of IR inhibits this vicious cycle, resulting in neuroprotection and improved neurological function. GSNO is a natural component of the human body, and its exogenous

  17. Salsalate and Adiponectin Improve Palmitate-Induced Insulin Resistance via Inhibition of Selenoprotein P through the AMPK-FOXO1α Pathway.

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    Tae Woo Jung

    Full Text Available Selenoprotein P (SeP was recently identified as a hepatokine that induces insulin resistance (IR in rodents and humans. Recent clinical trials have shown that salsalate, a prodrug of salicylate, significantly lowers blood glucose levels and increases adiponectin concentrations. We examined the effects of salsalate and full length-adiponectin (fAd on the expression of SeP under hyperlipidemic conditions and explored their regulatory mechanism on SeP. In palmitate-treated HepG2 cells as well as high fat diet (HFD-fed male Spraque Dawley (SD rats and male db/db mice, SeP expression and its regulatory pathway, including AMPK-FOXO1α, were evaluated after administration of salsalate and salicylate. Palmitate treatment significantly increased SeP expression and aggravated IR, while knock-down of SeP by siRNA restored these changes in HepG2 cells. Palmitate-induced SeP expression was inhibited by both salsalate and salicylate, which was mediated by AMPK activation, and was blocked by AMPK siRNA or an inhibitor of AMPK. Chromatin immunoprecipitation (ChIP and electrophoretic mobility shift (EMSA assay showed that salsalate suppressed SeP expression by AMPK-mediated phosphorylation of FOXO1α. Moreover, fAd also reduced palmitate-induced SeP expression through the activation of AMPK, which results in improved IR. Both salsalate and salicylate treatment significantly improved glucose intolerance and insulin sensitivity, accompanied by reduced SeP mRNA and protein expression in HFD-fed rats and db/db mice, respectively. Taken together, we found that salsalate and adiponectin ameliorated palmitate-induced IR in hepatocytes via SeP inhibition through the AMPK-FOXO1α pathway. The regulation of SeP might be a novel mechanism mediating the anti-diabetic effects of salsalate and adiponectin.

  18. Ursolic acid inhibits adipogenesis in 3T3-L1 adipocytes through LKB1/AMPK pathway.

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    Yonghan He

    Full Text Available BACKGROUND: Ursolic acid (UA is a triterpenoid compound with multiple biological functions. This compound has recently been reported to possess an anti-obesity effect; however, the mechanisms are less understood. OBJECTIVE: As adipogenesis plays a critical role in obesity, the present study was conducted to investigate the effect of UA on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes. METHODS AND RESULTS: The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of UA for 6 days. The cells were determined for proliferation, differentiation, fat accumulation as well as the protein expressions of molecular targets that regulate or are involved in fatty acid synthesis and oxidation. The results demonstrated that ursolic acid at concentrations ranging from 2.5 µM to 10 µM dose-dependently attenuated adipogenesis, accompanied by reduced protein expression of CCAAT element binding protein β (C/EBPβ, peroxisome proliferator-activated receptor γ (PPARγ, CCAAT element binding protein α (C/EBPα and sterol regulatory element binding protein 1c (SREBP-1c, respectively. Ursolic acid increased the phosphorylation of acetyl-CoA carboxylase (ACC and protein expression of carnitine palmitoyltransferase 1 (CPT1, but decreased protein expression of fatty acid synthase (FAS and fatty acid-binding protein 4 (FABP4. Ursolic acid increased the phosphorylation of AMP-activated protein kinase (AMPK and protein expression of (silent mating type information regulation 2, homolog 1 (Sirt1. Further studies demonstrated that the anti-adipogenic effect of UA was reversed by the AMPK siRNA, but not by the Sirt1 inhibitor nicotinamide. Liver kinase B1 (LKB1, the upstream kinase of AMPK, was upregulated by UA. When LKB1 was silenced with siRNA or the inhibitor radicicol, the effect of UA on AMPK activation was diminished. CONCLUSIONS: Ursolic acid inhibited 3T3-L1 preadipocyte differentiation and adipogenesis through the LKB1/AMPK

  19. AMPK regulates autophagy by phosphorylating BECN1 at threonine 388

    Science.gov (United States)

    Zhang, Deyi; Wang, Wei; Sun, Xiujie; Xu, Daqian; Wang, Chenyao; Zhang, Qian; Wang, Huafei; Luo, Wenwen; Chen, Yan; Chen, Huaiyong; Liu, Zhixue

    2016-01-01

    ABSTRACT Macroautophagy/autophagy is a conserved catabolic process that recycles cytoplasmic material during low energy conditions. BECN1/Beclin1 (Beclin 1, autophagy related) is an essential protein for function of the class 3 phosphatidylinositol 3-kinase (PtdIns3K) complexes that play a key role in autophagy nucleation and elongation. Here, we show that AMP-activated protein kinase (AMPK) regulates autophagy by phosphorylating BECN1 at Thr388. Phosphorylation of BECN1 is required for autophagy upon glucose withdrawal. BECN1T388A, a phosphorylation defective mutant, suppresses autophagy through decreasing the interaction between PIK3C3 (phosphatidylinositol 3-kinase catalytic subunit type 3) and ATG14 (autophagy-related 14). The BECN1T388A mutant has a higher affinity for BCL2 than its wild-type counterpart; the mutant is more prone to dimer formation. Conversely, a BECN1 phosphorylation mimic mutant, T388D, has stronger binding to PIK3C3 and ATG14, and promotes higher autophagy activity than the wild-type control. These findings uncover a novel mechanism of autophagy regulation. PMID:27304906

  20. The effects of altitude training on the AMPK-related glucose transport pathway in the red skeletal muscle of both lean and obese Zucker rats.

    Science.gov (United States)

    Chen, Yu-Ching; Lee, Shin-Da; Kuo, Cha-Hua; Ho, Low-Tone

    2011-01-01

    The skeletal muscle AMP-activated protein kinase (AMPK)-related glucose transport pathway is involved in glucose homeostasis. In this study, we examined whether obese control Zucker rats had abnormal expression of proteins in the LKB1-AMPK-AS160-GLUT4 pathway in red gastrocnemius muscle compared to that in lean (normal) control Zucker rats. We also compared the chronic training effects of exercise, hypoxia, and altitude training on this pathway in lean and obese rats. At sea level, lean and obese rats were divided into 4 groups for 6 weeks training as follows: 1) control; 2) exercise (progressive daily swimming-exercise training with comparable exercise signals between the two groups); 3) hypoxia (8 hours of daily 14% O2 exposure); and 4) exercise plus hypoxia (also called altitude training). Seven animals were used for each group. The obese rats in the control group had higher body weights, elevated fasting insulin and glucose levels, and higher baseline levels of muscle AMPK and AS160 phosphorylation compared with those of lean control rats. For obese Zucker rats in the exercise or hypoxia groups, the muscle AMPK phosphorylation level was significantly decreased compared with that of the control group. For obese Zucker rats in the altitude training group, the levels of AMPK, AS160 phosphorylation, fasting insulin, and fasting glucose were decreased concomitant with an approximate 50% increase in the muscle GLUT4 protein level compared with those of the control group. In lean rats, the altitude training efficiently lowered fasting glucose and insulin levels and increased muscle AMPK and AS160 phosphorylation as well as GLUT4 protein levels. Our results provide evidence that long-term altitude training may be a potentially effective nonpharmacological strategy for treating and preventing insulin resistance based on its effects on the skeletal muscle AMPK-AS160-GLUT4 pathway.

  1. Increase in hypothalamic AMPK phosphorylation induced by prolonged exposure to LPS involves ghrelin and CB1R signaling.

    Science.gov (United States)

    Rivas, Priscila M S; Vechiato, Fernanda M V; Borges, Beatriz C; Rorato, Rodrigo; Antunes-Rodrigues, Jose; Elias, Lucila L K

    2017-07-01

    Acute administration of lipopolysaccharide (LPS) from Gram-negative bacteria induces hypophagia. However, the repeated administration of LPS leads to desensitization of hypophagia, which is associated with increased hypothalamic p-AMPK expression. Because ghrelin and endocannabinoids modulate AMPK activity in the hypothalamus, we hypothesized that these neuromodulators play a role in the reversal of tolerance to hypophagia in rats under long-term exposure to LPS. Male Wistar rats were treated with single (1 LPS, 100μg/kg body weight, ip) or repeated injections of LPS over 6days (6 LPS). Food intake was reduced in the 1 LPS, but not in the 6 LPS group. 6 LPS rats showed an increased serum concentration of acylated ghrelin and reduced ghrelin receptor mRNA expression in the hypothalamus. Ghrelin injection (40μg/kg body weight, ip) increased food intake, body weight gain, p-AMPK hypothalamic expression, neuropeptide Y (NPY) and Agouti related peptide (AgRP) mRNA expression in control animals (Saline). However, in 6 LPS rats, ghrelin did not alter these parameters. Central administration of a CB1R antagonist (AM251, 200ng/μl in 5μl/rat) induced hypophagia in 6 LPS animals, suggesting that the endocannabinoid system contributes to preserved food intake during LPS tolerance. In the presence of AM251, the ability of ghrelin to phosphorylate AMPK in the hypothalamus of 6 LPS group was restored, but not its orexigenic effect. Our data highlight that the orexigenic effects of ghrelin require CB1R signaling downstream of AMPK activation. Moreover, CB1R-mediated pathways contribute to the absence of hypophagia during repeated exposure to endotoxin. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. High density lipoprotein structural changes and drug response in lipidomic profiles following the long-term fenofibrate therapy in the FIELD substudy.

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    Laxman Yetukuri

    Full Text Available In a recent FIELD study the fenofibrate therapy surprisingly failed to achieve significant benefit over placebo in the primary endpoint of coronary heart disease events. Increased levels of atherogenic homocysteine were observed in some patients assigned to fenofibrate therapy but the molecular mechanisms behind this are poorly understood. Herein we investigated HDL lipidomic profiles associated with fenofibrate treatment and the drug-induced Hcy levels in the FIELD substudy. We found that fenofibrate leads to complex HDL compositional changes including increased apoA-II, diminishment of lysophosphatidylcholines and increase of sphingomyelins. Ethanolamine plasmalogens were diminished only in a subgroup of fenofibrate-treated patients with elevated homocysteine levels. Finally we performed molecular dynamics simulations to qualitatively reconstitute HDL particles in silico. We found that increased number of apoA-II excludes neutral lipids from HDL surface and apoA-II is more deeply buried in the lipid matrix than apoA-I. In conclusion, a detailed molecular characterization of HDL may provide surrogates for predictors of drug response and thus help identify the patients who might benefit from fenofibrate treatment.

  3. HUBUNGAN DOSIS TEPUNG GEMBILI (Dioscorea esculenta DENGAN TINGKAT EKSPRESI ENZIM Ampk-α2 PADA MODEL TIKUS DIABETES MELITUS

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    neni oktiyani

    2015-06-01

    Full Text Available Abstract: Alternative methods of controlling glucose levels in patients with diabetes is by type of food, either by utilizing yam flour. At the flour contained inulin and resistant starch that can activate the enzyme AMPK-α2. Activation of these enzymes will stimulate glucose transport in skeletal muscle and liver, thus causing a decrease in glucose production. Varying doses of flour is expected to affect the expression of AMPK-α2. This study aims to dosage relationship yam flour (Dioscorea esculenta with tigkat-α2 AMPK enzyme expression in the nucleus skeletal muscle and liver in mouse models of diabetes mellitus. The study was a quasi-experimental design with Post Test Only Group Design. Rats were divided into 5 (five groups, healthy mice, the mice with type 2 diabetes, and type 2 groups of diabetic rats with dietary intake yam flour addition of 1.25 g (TG-1:25,, 2.5 g (TG -2.5, 5.0 g (TG-5.0. Yam flour is mixed into the rat diet feed with varying doses. The results showed no significant correlation between the dose of yam flour with AMPK-α2 expression levels in skeletal muscle nuclei (p = 0.312 and liver (p = 0.474 in a mouse model of DM. The need for other studies using other types of food as an alternative arrangement of food for patients with diabetes Keywords: diabetes mellitus type 2, AMPK-α2, yam flour Abstrak: Metode alternatif pengendalian kadar glukosa pada penderita DM adalah dengan pengaturan jenis makanan, salah satunya dengan memanfaatkan tepung gembili. Pada tepung terdapat inulin dan pati resisten yang dapat mengaktivasi enzim Ampk-α2. Aktivasi enzim ini akan menstimulasi transpor glukosa di otot skelet dan hepar, sehingga menyebabkan terjadinya penurunan produksi glukosa. Dosis bervariasi dari tepung diharapkan mampu berpengaruh terhadap ekspresi Ampk-α2. Penelitian ini bertujuan untuk hubungan dosis tepung gembili (Dioscorea esculenta dengan tigkat ekspresi enzim Ampk-α2 di nukleus otot skelet dan hepar pada model

  4. Fasting increases the phosphorylation of AMPK and expression of sirtuin1 in muscle of adult male northern elephant seals (Mirounga angustirostris).

    Science.gov (United States)

    Lee, Debby; Martinez, Bridget; Crocker, Daniel E; Ortiz, Rudy M

    2017-02-01

    Fasting typically suppresses thyroid hormone (TH)-mediated cellular events and increases sirtuin 1 (SIRT1) activity. THs may regulate metabolism through nongenomic pathways and directly through activation of adenosine monophosphate-activated protein kinase (AMPK). Adult male elephant seals ( Mirounga angustirostris ) are active, hypermetabolic, and normothermic during their annual breeding fast, which is characterized by stable TH levels. However, the contribution of TH to maintenance of their fasting metabolism is unknown. To investigate the fasting effects on cellular TH-mediated events and its potential association with SIRT1 and AMPK, we quantified plasma TH levels, mRNA expressions of muscle SIRT1 and TH-associated genes as well as the phosphorylation of AMPK in adult, male northern elephant seals ( n  = 10/fasting period) over 8 weeks of fasting (early vs. late). Deiodinase type I (DI1) expression increased twofold with fasting duration suggesting that the potential for TH-mediated cellular signaling is increased. AMPK phosphorylation increased 61 ± 21% with fasting suggesting that cellular metabolism is increased. The mRNA expression of the TH transporter, monocarboxylate transporter 10 (MCT10), increased 2.4-fold and the TH receptor (THr β -1) decreased 30-fold suggesting that cellular uptake of T 4 is increased, but its subsequent cellular effects such as activation of AMPK are likely nongenomic. The up-regulation of SIRT1 mRNA expression (2.6-fold) likely contributes to the nongenomic activation of AMPK by TH, which may be necessary to maintain the expression of PGC-1 α These coordinated changes likely contribute to the up-regulation of mitochondrial metabolism to support the energetic demands associated with prolonged fasting in adult seals. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  5. Proglucagon Promoter Cre-Mediated AMPK Deletion in Mice Increases Circulating GLP-1 Levels and Oral Glucose Tolerance.

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    Sophie R Sayers

    Full Text Available Enteroendocrine L-cells synthesise and release the gut hormone glucagon-like peptide-1 (GLP-1 in response to food transit. Deletion of the tumour suppressor kinase LKB1 from proglucagon-expressing cells leads to the generation of intestinal polyps but no change in circulating GLP-1 levels. Here, we explore the role of the downstream kinase AMP-activated protein kinase (AMPK in these cells.Loss of AMPK from proglucagon-expressing cells was achieved using a preproglucagon promoter-driven Cre (iGluCre to catalyse recombination of floxed alleles of AMPKα1 and α2. Oral and intraperitoneal glucose tolerance were measured using standard protocols. L-cell mass was measured by immunocytochemistry. Hormone and peptide levels were measured by electrochemical-based luminescence detection or radioimmunoassay.Recombination with iGluCre led to efficient deletion of AMPK from intestinal L- and pancreatic alpha-cells. In contrast to mice rendered null for LKB1 using the same strategy, mice deleted for AMPK displayed an increase (WT: 0.05 ± 0.01, KO: 0.09±0.02%, p<0.01 in L-cell mass and elevated plasma fasting (WT: 5.62 ± 0.800 pg/ml, KO: 14.5 ± 1.870, p<0.01 and fed (WT: 15.7 ± 1.48pg/ml, KO: 22.0 ± 6.62, p<0.01 GLP-1 levels. Oral, but not intraperitoneal, glucose tolerance was significantly improved by AMPK deletion, whilst insulin and glucagon levels were unchanged despite an increase in alpha to beta cell ratio (WT: 0.23 ± 0.02, KO: 0.33 ± 0.03, p<0.01.AMPK restricts L-cell growth and GLP-1 secretion to suppress glucose tolerance. Targeted inhibition of AMPK in L-cells may thus provide a new therapeutic strategy in some forms of type 2 diabetes.

  6. Hydrogen Sulfide and/or Ammonia Reduces Spermatozoa Motility through AMPK/AKT Related Pathways

    Science.gov (United States)

    Zhao, Yong; Zhang, Wei-Dong; Liu, Xin-Qi; Zhang, Peng-Fei; Hao, Ya-Nan; Li, Lan; Chen, Liang; Shen, Wei; Tang, Xiang-Fang; Min, Ling-Jiang; Meng, Qing-Shi; Wang, Shu-Kun; Yi, Bao; Zhang, Hong-Fu

    2016-11-01

    A number of emerging studies suggest that air pollutants such as hydrogen sulfide (H2S) and ammonia (NH3) may cause a decline in spermatozoa motility. The impact and underlying mechanisms are currently unknown. Boar spermatozoa (in vitro) and peripubertal male mice (in vivo) were exposed to H2S and/or NH3 to evaluate the impact on spermatozoa motility. Na2S and/or NH4Cl reduced the motility of boar spermatozoa in vitro. Na2S and/or NH4Cl disrupted multiple signaling pathways including decreasing Na+/K+ ATPase activity and protein kinase B (AKT) levels, activating Adenosine 5‧-monophosphate (AMP)-activated protein kinase (AMPK) and phosphatase and tensin homolog deleted on chromosome ten (PTEN), and increasing reactive oxygen species (ROS) to diminish boar spermatozoa motility. The increase in ROS might have activated PTEN, which in turn diminished AKT activation. The ATP deficiency (indicated by reduction in Na+/K+ ATPase activity), transforming growth factor (TGFβ) activated kinase-1 (TAK1) activation, and AKT deactivation stimulated AMPK, which caused a decline in boar spermatozoa motility. Simultaneously, the deactivation of AKT might play some role in the reduction of boar spermatozoa motility. Furthermore, Na2S and/or NH4Cl declined the motility of mouse spermatozoa without affecting mouse body weight gain in vivo. Findings of the present study suggest that H2S and/or NH3 are adversely associated with spermatozoa motility.

  7. Novel compound from Polygonum multiflorum inhibits inflammatory response in LPS-stimulated microglia by upregulating AMPK/Nrf2 pathways.

    Science.gov (United States)

    Park, Sun Young; Jin, Mei Ling; Chae, Seon Yeong; Ko, Min Jung; Choi, Yung Hyun; Park, Geuntae; Choi, Young-Whan

    2016-11-01

    Polygonum multiflorum extracts are known to improve memory and learning ability, and have neuroprotective and anti-aging activity. However, its function and the underlying mechanisms in neuroinflammation-mediated neurodegenerative disease remain poorly understood. In the present study, we investigated the anti-neuroinflammatory effects of several compounds from P. multiflorum, and found a novel compound, CRPE55IB. The CRPE55IB-induced suppression of NO and PGE 2 production correlated with inhibition of iNOS and COX-2 protein expression and promoter activity in lipopolysaccharide (LPS)-stimulated microglia. CRPE55IB also reduced the production of pro-inflammatory cytokines (TNF-α and IL-6) induced by LPS. Furthermore, investigation of the molecular mechanism indicated that CRPE55IB inhibited LPS-induced NF-κB activation by inactivating phosphorylation of IKKα/β, and phosphorylation and degradation of IκBα. We further found that CRPE55IB inhibited the phosphorylation of ERK and JNK at a lower concentration than that for p38 MAPK. Further experiments revealed that CRPE55IB treatment considerably increased the activation of Nrf2/ARE, and the expression of its target genes, including HO-1 and NQO1. Moreover, the Knockdown of Nrf2, HO-1, and NQO1 by siRNA abrogated the inhibitory effect of CRPE55IB on iNOS and COX-2 promoter activity. CRPE55IB also induced phosphorylation of AMPK/LKB/CaMKII in microglia. Analysis using a specific inhibitor of AMPK demonstrated that AMPK activation was involved in CRPE55IB-induced HO-1 and NQO1 expression. In addition, the CRPE55IB-induced anti-neuroinflammatory effect was abrogated by a specific inhibitor of AMPK, indicating the important role of AMPK in CRPE55IB-induced anti-neuroinflammation. Collectively, these results demonstrate that CRPE55IB exerts anti-neuroinflammatory effects against LPS via the Nrf2/AMPK signaling pathways. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Hepatic p38α regulates gluconeogenesis by suppressing AMPK.

    Science.gov (United States)

    Jing, Yanyan; Liu, Wei; Cao, Hongchao; Zhang, Duo; Yao, Xuan; Zhang, Shengjie; Xia, Hongfeng; Li, Dan; Wang, Yu-cheng; Yan, Jun; Hui, Lijian; Ying, Hao

    2015-06-01

    It is proposed that p38 is involved in gluconeogenesis, however, the genetic evidence is lacking and precise mechanisms remain poorly understood. We sought to delineate the role of hepatic p38α in gluconeogenesis during fasting by applying a loss-of-function genetic approach. We examined fasting glucose levels, performed pyruvate tolerance test, imaged G6Pase promoter activity, as well as determined the expression of gluconeogenic genes in mice with a targeted deletion of p38α in liver. Results were confirmed both in vivo and in vitro by using an adenoviral dominant-negative form of p38α (p38α-AF) and the constitutively active mitogen-activated protein kinase 6, respectively. Adenoviral dominant-negative form of AMP-activated protein kinase α (DN-AMPKα) was employed to test our proposed model. Mice lacking hepatic p38α exhibited reduced fasting glucose level and impaired gluconeogenesis. Interestingly, hepatic deficiency of p38α did not result in an alteration in CREB phosphorylation, but led to an increase in AMPKα phosphorylation. Adenoviral DN-AMPKα could abolish the effect of p38α-AF on gluconeogenesis. Knockdown of up-steam transforming growth factor β-activated kinase 1 decreased the AMPKα phosphorylation induced by p38α-AF, suggesting a negative feedback loop. Consistently, inverse correlations between p38 and AMPKα phosphorylation were observed during fasting and in diabetic mouse models. Importantly, adenoviral p38α-AF treatment ameliorated hyperglycemia in diabetic mice. Our study provides evidence that hepatic p38α functions as a negative regulator of AMPK signaling in maintaining gluconeogenesis, dysregulation of this regulatory network contributes to unrestrained gluconeogenesis in diabetes, and hepatic p38α could be a drug target for hyperglycemia. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  9. Role of 5'AMP-activated protein kinase in skeletal muscle

    DEFF Research Database (Denmark)

    Treebak, Jonas Thue; Wojtaszewski, Jørgen F. P.

    2008-01-01

    5'AMP-activated protein kinase (AMPK) is recognized as an important intracellular energy sensor, shutting down energy-consuming processes and turning on energy-generating processes. Discovery of target proteins of AMPK has dramatically increased in the past 10 years. Historically, AMPK was first...

  10. Activation of AMP-activated protein kinase by tributyltin induces neuronal cell death

    International Nuclear Information System (INIS)

    Nakatsu, Yusuke; Kotake, Yaichiro; Hino, Atsuko; Ohta, Shigeru

    2008-01-01

    AMP-activated protein kinase (AMPK), a member of the metabolite-sensing protein kinase family, is activated by energy deficiency and is abundantly expressed in neurons. The environmental pollutant, tributyltin chloride (TBT), is a neurotoxin, and has been reported to decrease cellular ATP in some types of cells. Therefore, we investigated whether TBT activates AMPK, and whether its activation contributes to neuronal cell death, using primary cultures of cortical neurons. Cellular ATP levels were decreased 0.5 h after exposure to 500 nM TBT, and the reduction was time-dependent. It was confirmed that most neurons in our culture system express AMPK, and that TBT induced phosphorylation of AMPK. Compound C, an AMPK inhibitor, reduced the neurotoxicity of TBT, suggesting that AMPK is involved in TBT-induced cell death. Next, the downstream target of AMPK activation was investigated. Nitric oxide synthase, p38 phosphorylation and Akt dephosphorylation were not downstream of TBT-induced AMPK activation because these factors were not affected by compound C, but glutamate release was suggested to be controlled by AMPK. Our results suggest that activation of AMPK by TBT causes neuronal death through mediating glutamate release

  11. Adrenaline is a critical mediator of acute exercise-induced AMP-activated protein kinase activation in adipocytes

    Science.gov (United States)

    Koh, Ho-Jin; Hirshman, Michael F.; He, Huamei; Li, Yangfeng; Manabe, Yasuko; Balschi, James A.; Goodyear, Laurie J.

    2007-01-01

    Exercise increases AMPK (AMP-activated protein kinase) activity in human and rat adipocytes, but the underlying molecular mechanisms and functional consequences of this activation are not known. Since adrenaline (epinephrine) concentrations increase with exercise, in the present study we hypothesized that adrenaline activates AMPK in adipocytes. We show that a single bout of exercise increases AMPKα1 and α2 activities and ACC (acetyl-CoA carboxylase) Ser79 phosphorylation in rat adipocytes. Similarly to exercise, adrenaline treatment in vivo increased AMPK activities and ACC phosphorylation. Pre-treatment of rats with the β-blocker propranolol fully blocked exercise-induced AMPK activation. Increased AMPK activity with exercise and adrenaline treatment in vivo was accompanied by an increased AMP/ATP ratio. Adrenaline incubation of isolated adipocytes also increased the AMP/ATP ratio and AMPK activities, an effect blocked by propranolol. Adrenaline incubation increased lipolysis in isolated adipocytes, and Compound C, an AMPK inhibitor, attenuated this effect. Finally, a potential role for AMPK in the decreased adiposity associated with chronic exercise was suggested by marked increases in AMPKα1 and α2 activities in adipocytes from rats trained for 6 weeks. In conclusion, both acute and chronic exercise are significant regulators of AMPK activity in rat adipocytes. Our findings suggest that adrenaline plays a critical role in exercise-stimulated AMPKα1 and α2 activities in adipocytes, and that AMPK can function in the regulation of lipolysis. PMID:17253964

  12. Effect of Ceolus KG-802 on the dissolution rate of fenofibrate liquisolid tablets: Preformulation and formulation development studies.

    Science.gov (United States)

    Karmarkar, A B

    2010-12-01

    The purpose of the present research was to study the effects of Ceolus KG-802 on the dissolution behavior of fenofibrate liquisolid tablets. The fenofibrate liquisolid tablets were formulated using the mathematical model described by Spireas et al. In the present research, Ceolus KG-802, a different form of microcrystalline cellulose (PH 102 grade), was used as a carrier material. The developed formulations were subjected to preformulation studies such as differential scanning calorimetry, X-ray powder diffraction, and determination of flow properties. The liquisolid tablets prepared were studied for their in vitro dissolution and compared to liquisolid tablets prepared using Avicel PH 102. The in vitro dissolution profiles of liquisolid tablets prepared using Ceolus KG-802 indicated slower dissolution than those of liquisolid tablets prepared using Avicel PH 102, which was a subject of earlier studies. This might be due to the particle size, shape, and characteristic properties of Ceolus KG-802.

  13. Cytosolic malate dehydrogenase regulates RANKL-mediated osteoclastogenesis via AMPK/c-Fos/NFATc1 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Se Jeong [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Gu, Dong Ryun [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Jin, Su Hyun [Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Park, Keun Ha [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Lee, Seoung Hoon, E-mail: leesh2@wku.ac.kr [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Wonkwang Institute of Biomaterials and Implant, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of)

    2016-06-17

    Cytosolic malate dehydrogenase (malate dehydrogenase 1, MDH1) plays pivotal roles in the malate/aspartate shuttle that might modulate metabolism between the cytosol and mitochondria. In this study, we investigated the role of MDH1 in osteoclast differentiation and formation. MDH1 expression was induced by receptor activator of nuclear factor kappa-B ligand (RANKL) treatment. Knockdown of MDH1 by infection with retrovirus containing MDH1-specific shRNA (shMDH1) reduced mature osteoclast formation and bone resorption activity. Moreover, the expression of marker genes associated with osteoclast differentiation was downregulated by shMDH1 treatment, suggesting a role of MDH1 in osteoclast differentiation. In addition, intracellular ATP production was reduced following the activation of adenosine 5′ monophosphate-activated protein kinase (AMPK), a cellular energy sensor and negative regulator of RANKL-induced osteoclast differentiation, in shMDH1-infected osteoclasts compared to control cells. In addition, the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a critical transcription factor of osteoclastogenesis, was decreased with MDH1 knockdown during RANKL-mediated osteoclast differentiation. These findings provide strong evidence that MDH1 plays a critical role in osteoclast differentiation and function via modulation of the intracellular energy status, which might affect AMPK activity and NFATc1 expression.

  14. Sepsis and mechnaical ventilation restrain translation initiation in skeletal muscle by inducing AMPK-associated TSC[2] restriction of mTOR signaling in pigs

    Science.gov (United States)

    In skeletal muscle, AMP-activated protein kinase (AMPK) acts as a cellular energy sensor of AMP: ATP and modulates translation by repressing mammalian target of rapamycin (mTOR) activation. Endotoxin (LPS)-induced sepsis reduces muscle protein synthesis by blunting translation initiation. We hypothe...

  15. Significance and suppression of redundant IL17 responses in acute allograft rejection by bioinformatics based drug repositioning of fenofibrate.

    Directory of Open Access Journals (Sweden)

    Silke Roedder

    Full Text Available Despite advanced immunosuppression, redundancy in the molecular diversity of acute rejection (AR often results in incomplete resolution of the injury response. We present a bioinformatics based approach for identification of these redundant molecular pathways in AR and a drug repositioning approach to suppress these using FDA approved drugs currently available for non-transplant indications. Two independent microarray data-sets from human renal allograft biopsies (n = 101 from patients on majorly Th1/IFN-y immune response targeted immunosuppression, with and without AR, were profiled. Using gene-set analysis across 3305 biological pathways, significant enrichment was found for the IL17 pathway in AR in both data-sets. Recent evidence suggests IL17 pathway as an important escape mechanism when Th1/IFN-y mediated responses are suppressed. As current immunosuppressions do not specifically target the IL17 axis, 7200 molecular compounds were interrogated for FDA approved drugs with specific inhibition of this axis. A combined IL17/IFN-y suppressive role was predicted for the antilipidemic drug Fenofibrate. To assess the immunregulatory action of Fenofibrate, we conducted in-vitro treatment of anti-CD3/CD28 stimulated human peripheral blood cells (PBMC, and, as predicted, Fenofibrate reduced IL17 and IFN-γ gene expression in stimulated PMBC. In-vivo Fenofibrate treatment of an experimental rodent model of cardiac AR reduced infiltration of total leukocytes, reduced expression of IL17/IFN-y and their pathway related genes in allografts and recipients' spleens, and extended graft survival by 21 days (p<0.007. In conclusion, this study provides important proof of concept that meta-analyses of genomic data and drug databases can provide new insights into the redundancy of the rejection response and presents an economic methodology to reposition FDA approved drugs in organ transplantation.

  16. AMPK-mediated up-regulation of mTORC2 and MCL-1 compromises the anti-cancer effects of aspirin

    Science.gov (United States)

    Hua, Hui; Yin, Yancun; Wang, Jiao; Luo, Ting; Jiang, Yangfu

    2016-01-01

    AMP-activated protein kinase (AMPK) is an important energy sensor that may inhibit cell proliferation or promote cell survival during stresses. Besides cyclooxygenase, AMPK is another target of the nonsteroid anti-inflammatory agent aspirin. Preclinical and clinical investigations demonstrate that aspirin can inhibit several types of cancer such as colorectal adenomas and hepatocellular carcinoma (HCC). However, little is known about the cellular response to aspirin that may lead to aspirin resistance. Here, we show that aspirin induces the expression of MCL-1 in HepG2 and SW480 cells through AMPK-mTOR-Akt/ERK axis. Treatment of HepG2 and SW480 cells with aspirin leads to increased MCL-1 expression, Akt and ERK1/2 phosphorylation. Inhibition of Akt/MEK abrogates the induction of MCL-1 by aspirin. Aspirin activates AMPK, which in turn up-regulates mTORC2 activity, Akt, ERK1/2 phosphorylation and MCL-1 expression. MCL-1 knockdown sensitizes cancer cells to aspirin-induced apoptosis. Combination of aspirin and AMPK, Akt or MEK inhibitor results in more significant inhibition of cell proliferation and induction of apoptosis than single agent. Moreover, sorafenib blocks aspirin-induced MCL-1 up-regulation. Combination of aspirin and sorafenib leads to much more cell death and less cell proliferation than each drug alone. Treatment of HCC and colon cancer xenografts with both aspirin and sorafenib results in more significant tumor suppression than single agent. These data demonstrate that AMPK-mediated up-regulation of mTORC2 and MCL-1 may compromise the anticancer effects of aspirin. Combination of aspirin and sorafenib may be an effective regimen to treat HCC and colon cancer. PMID:26918349

  17. Contraction-stimulated glucose transport in muscle is controlled by AMPK and mechanical stress but not sarcoplasmatic reticulum Ca2+ release

    Directory of Open Access Journals (Sweden)

    Thomas E. Jensen

    2014-10-01

    Full Text Available Understanding how muscle contraction orchestrates insulin-independent muscle glucose transport may enable development of hyperglycemia-treating drugs. The prevailing concept implicates Ca2+ as a key feed forward regulator of glucose transport with secondary fine-tuning by metabolic feedback signals through proteins such as AMPK. Here, we demonstrate in incubated mouse muscle that Ca2+ release is neither sufficient nor strictly necessary to increase glucose transport. Rather, the glucose transport response is associated with metabolic feedback signals through AMPK, and mechanical stress-activated signals. Furthermore, artificial stimulation of AMPK combined with passive stretch of muscle is additive and sufficient to elicit the full contraction glucose transport response. These results suggest that ATP-turnover and mechanical stress feedback are sufficient to fully increase glucose transport during muscle contraction, and call for a major reconsideration of the established Ca2+ centric paradigm.

  18. Investigating the correlation between in vivo absorption and in vitro release of fenofibrate from lipid matrix particles in biorelevant medium.

    Science.gov (United States)

    Borkar, Nrupa; Xia, Dengning; Holm, René; Gan, Yong; Müllertz, Anette; Yang, Mingshi; Mu, Huiling

    2014-01-23

    Lipid matrix particles (LMP) may be used as better carriers for poorly water-soluble drugs than liquid lipid carriers because of reduced drug mobilization in the formulations. However, the digestion process of solid lipid particles and their effect on the absorption of poorly water-soluble drugs are not fully understood. This study aimed at investigating the effect of particle size of LMP on drug release in vitro as well as absorption in vivo in order to get a better understanding on the effect of degradation of lipid particles on drug solubilisation and absorption. Fenofibrate, a model poorly water-soluble drug, was incorporated into LMP in this study using probe ultrasound sonication. The resultant LMP were characterised in terms of particle size, size distribution, zeta potential, entrapment efficiency, in vitro lipolysis and in vivo absorption in rat model. LMP of three different particle sizes i.e. approximately 100 nm, 400 nm, and 10 μm (microparticles) were produced with high entrapment efficiencies. The in vitro lipolysis study showed that the recovery of fenofibrate in the aqueous phase for 100 nm and 400 nm LMP was significantly higher (pmicroparticles>control. In summary, the present study demonstrated the particle size dependence of bioavailability of fenofibrate loaded LMP in rat model which correlates well with the in vitro drug release performed in the biorelevant medium. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. High-performance liquid chromatography and derivative spectrophotometry for simultaneous determination of pravastatin and fenofibrate in the dosage form

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    Hefnawy Mohamed M.

    2014-12-01

    Full Text Available High performance liquid chromatography (HPLC and second-order derivative spectrophotometry have been used for simultaneous determination of pravastatin (PS and fenofibrate (FF in pharmaceutical formulations. HPLC separation was performed on a phenyl HYPERSIL C18 column (125 mm × 4.6 mm i.d., 5 μm particle diameter in the isocratic mode using a mobile phase acetonitrile/0.1 % diethyl amine (50:50, V/V, pH 4.5 pumped at a flow rate of 1.0 mL min-1. Measurement was made at 240 nm. Both drugs were well resolved on the stationary phase, with retention times of 2.15 and 5.79 min for PS and FF, respectively. Calibration curves were linear (R = 0.999 for PS and 0.996 for FF in the concentration range of 5-50 and 20-200 µg mL-1 for PS and FF, respectively. Pravastatin and fenofibrate were quantitated in combined preparations also using the second-order derivative response at 237.6 and 295.1 nm for PS and FF, respectively. Calibration curves were linear, with the correlation coefficient R = 0.999 for pravastatin and fenofibrate, in the concentration range of 5-20 and 3-20 µg mL-1 for PS and FF, respectively. Both methods were fully validated and compared, the results confirmed that they were highly suitable for their intended purpose.

  20. Gastrointestinal behavior of nano- and microsized fenofibrate: In vivo evaluation in man and in vitro simulation by assessment of the permeation potential.

    Science.gov (United States)

    Hens, Bart; Brouwers, Joachim; Corsetti, Maura; Augustijns, Patrick

    2015-09-18

    The purpose of this study was (i) to evaluate the gastrointestinal behavior of micro- and nanosized fenofibrate in humans and (ii) to develop a simple yet qualitatively predictive in vitro setup that simulates the observed absorption-determining factors. Commercially available micro- and nanoparticles of fenofibrate (Lipanthyl® and Lipanthylnano®, respectively) were administered orally to five healthy volunteers in fasting and postprandial conditions. Intraluminal and systemic drug concentrations were determined as reference data for the development of a predictive in vitro setup. To capture the observed solubility/permeability interplay, in vitro dissolution testing was performed in the presence of a permeation bag with sink conditions. In fasting conditions, intake of nanosized fenofibrate generated increased duodenal concentrations compared to microsized fenofibrate, which was reflected in an improved systemic exposure. In postprandial conditions, duodenal concentrations were greatly enhanced for both formulations, however without an accompanying increase in systemic exposure. It appeared that micellar encapsulation of the highly lipohilic fenofibrate limited its potential to permeate from fed state intestinal fluids. To capture these in vivo observations in an in vitro setup, classic dissolution testing was combined with permeation assessment into a permeation bag with sink conditions. In case of fasting conditions, the dissolution/permeation approach allowed for an improved discriminative power between micro- and nanosized fenofibrate by better simulating the dynamic interplay of dissolution and absorption. In case of postprandial conditions, the observed solubility-permeability interplay could be simulated using the dissolution/permeation approach in combination with biorelevant media (FeSSGFFortimel and FeSSIF-V2) to mimic micellar entrapment and reduced permeation potential of fenofibrate. For the first time, reduced permeation of a lipophilic drug

  1. A Novel Mechanism by Which SDF-1β Protects Cardiac Cells From Palmitate-Induced Endoplasmic Reticulum Stress and Apoptosis via CXCR7 and AMPK/p38 MAPK-Mediated Interleukin-6 Generation

    Science.gov (United States)

    Zhao, Yuguang; Tan, Yi; Xi, Shugang; Li, Yunqian; Li, Cai; Cui, Jiuwei; Yan, Xiaoqing; Li, Xiaokun; Wang, Guanjun; Li, Wei; Cai, Lu

    2013-01-01

    We studied the protective effect of stromal cell-derived factor-1β (SDF-1β) on cardiac cells from lipotoxicity in vitro and diabetes in vivo. Exposure of cardiac cells to palmitate increased apoptosis by activating NADPH oxidase (NOX)–associated nitrosative stress and endoplasmic reticulum (ER) stress, which was abolished by pretreatment with SDF-1β via upregulation of AMP-activated protein kinase (AMPK)–mediated p38 mitogen-activated protein kinase (MAPK) phosphorylation and interleukin-6 (IL-6) production. The SDF-1β cardiac protection could be abolished by inhibition of AMPK, p38 MAPK, or IL-6. Activation of AMPK or addition of recombinant IL-6 recaptured a similar cardiac protection. SDF-1β receptor C-X-C chemokine receptor type 4 (CXCR4) antagonist AMD3100 or CXCR4 small interfering RNA could not, but CXCR7 small interfering RNA completely abolished SDF-1β’s protection from palmitate-induced apoptosis and activation of AMPK and p38 MAPK. Administration of SDF-1β to diabetic rats, induced by feeding a high-fat diet, followed by a small dose of streptozotocin, could significantly reduce cardiac apoptosis and increase AMPK phosphorylation along with prevention of diabetes-induced cardiac oxidative damage, inflammation, hypertrophy, and remodeling. These results showed that SDF-1β protects against palmitate-induced cardiac apoptosis, which is mediated by NOX-activated nitrosative damage and ER stress, via CXCR7, to activate AMPK/p38 MAPK–mediated IL-6 generation. The cardiac protection by SDF-1β from diabetes-induced oxidative damage, cell death, and remodeling was also associated with AMPK activation. PMID:23423573

  2. Chronic Caloric Restriction and Exercise Improve Metabolic Conditions of Dietary-Induced Obese Mice in Autophagy Correlated Manner without Involving AMPK

    Directory of Open Access Journals (Sweden)

    Mingxia Cui

    2013-01-01

    Full Text Available Aim. To investigate the role of AMPK activation and autophagy in mediating the beneficial effects of exercise and caloric restriction in obesity. Methods. Dietary-induced obesity mice were made and divided into 5 groups; one additional group of normal mice serves as control. Mice in each group received different combinations of interventions including low fat diet, caloric restriction, and exercise. Then their metabolic conditions were assessed by measuring serum glucose and insulin, serum lipids, and liver function. AMPK phosphorylation and autophagy activity were detected by western blotting. Results. Obese mice models were successfully induced by high fat diet. Caloric restriction consistently improved the metabolic conditions of the obese mice, and the effects are more prominent than the mice that received only exercise. Also, caloric restriction, exercise, and low fat diet showed a synergistic effect in the improvement of metabolic conditions. Western blotting results showed that this improvement was not related with the activation of AMPK in liver, skeletal muscle, or heart but correlates well with the autophagy activity. Conclusion. Caloric restriction has more prominent beneficial effects than exercise in dietary-induced obese mice. These effects are correlated with the autophagy activity and may be independent of AMPK activation.

  3. Differential regulation by AMP and ADP of AMPK complexes containing different γ subunit isoforms

    DEFF Research Database (Denmark)

    Ross, Fiona A; Jensen, Thomas Elbenhardt; Hardie, D Grahame

    2016-01-01

    The g subunits of heterotrimeric AMPK complexes contain the binding sites for the regulatory adenine nucleotides AMP, ADP and ATP. We addressed whether complexes containing different g isoforms display different responses to adenine nucleotides by generating cells stably expressing FLAG-tagged ve......The g subunits of heterotrimeric AMPK complexes contain the binding sites for the regulatory adenine nucleotides AMP, ADP and ATP. We addressed whether complexes containing different g isoforms display different responses to adenine nucleotides by generating cells stably expressing FLAG......-tagged versions of the g1, g2 or g3 isoform. When assayed at a physiological ATP concentration (5 mM), g1- and g2-containing complexes were allosterically activated almost 10-fold by AMP, with EC50 values one to two orders of magnitude lower than the ATP concentration. By contrast, g3 complexes were barely...... activated by AMP under these conditions, although we did observe some activation at lower ATP concentrations. Despite this, all three complexes were activated, due to increased Thr172 phosphorylation, when cells were incubated with mitochondrial inhibitors that increase cellular AMP. With g1 complexes...

  4. New metabolites of fenofibrate in Sprague–Dawley rats by UPLC-ESI-QTOF-MS-based metabolomics coupled with LC-MS/MS

    Science.gov (United States)

    Liu, A.; Chen, Y.; Yang, Z.; Feng, Y.; Rui, W.; Luo, W.; Liu, Y.; Gonzalez, F. J.; Dai, R.

    2009-01-01

    Fenofibrate has been widely used for the treatment of dyslipidaemia with a long history. Species differences of its metabolism were reported, but its metabolites in rodent have not been fully investigated.Urine and plasma samples were collected before and after oral dosages of fenofibrate in Sprague–Dawley rats. Urine samples were subjected to ultra-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) analysis, and projection to latent structures discriminant analysis was used for the identification of metabolites.New metabolites in urine and plasma were also studied by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The metabolism pathway was studied in rat hepatocytes. Synthesized and purchased authentic compounds were used for metabolite identification by LC-MS/MS.Five ever-reported metabolites were identified and another four new ones were found. Among these new metabolites, fenofibric acid taurine and reduced fenofibric acid taurine indicate new phase II conjugation pathway of fenofibrate. PMID:19350456

  5. A New Approach to the RP-HPLC Method for Simultaneous Estimation of Atorvastatin Calcium and Fenofibrate in Pharmaceutical Dosage Forms

    Directory of Open Access Journals (Sweden)

    S. D. Bhinge

    2012-01-01

    Full Text Available The present manuscript describes the development and validation of an isocratic reverse phase high-performance liquid chromatographic (RP-HPLC method for the estimation of Atorvastatin calcium and Fenofibrate in raw material and tablet. Atorvastatin Calcium, Fenofibrate and Diclofenac (internal standard were well separated using a reversed phase column and mobile phase consisting of acetonitrile:KH2PO4 (50 mM (72:28 v/v (pH 4.1. The mobile phase was pumped at 1.0 mL/min flow rate and atorvastatin calcium and fenofibrate were detected by UV-Vis detection at 260 nm. The retention time for atorvastatin calcium, Internal Standard and fenofibrate were 4.34, 5.35 and 12.05 min, respectively. The LOD and LOQ was found to be 1.95 and 4.80 µg/mL for atorvastatin calcium whereas for fenofibrate it was found to be 1.73 and 3.98 µg/mL in mobile phase. The developed method was validated by applying parameters as precision, accuracy, selectivity, reproducibility and system suitability tests.

  6. Environmental and genetic preconditioning for long-term anoxia responses requires AMPK in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Bobby L LaRue

    2011-02-01

    Full Text Available Preconditioning environments or therapeutics, to suppress the cellular damage associated with severe oxygen deprivation, is of interest to our understanding of diseases associated with oxygen deprivation. Wildtype C. elegans exposed to anoxia enter into a state of suspended animation in which energy-requiring processes reversibly arrest. C. elegans at all developmental stages survive 24-hours of anoxia exposure however, the ability of adult hermaphrodites to survive three days of anoxia significantly decreases. Mutations in the insulin-like signaling receptor (daf-2 and LIN-12/Notch (glp-1 lead to an enhanced long-term anoxia survival phenotype.In this study we show that the combined growth environment of 25°C and a diet of HT115 E. coli will precondition adult hermaphrodites to survive long-term anoxia; many of these survivors have normal movement after anoxia treatment. Animals fed the drug metformin, which induces a dietary-restriction like state in animals and activates AMPK in mammalian cell culture, have a higher survival rate when exposed to long-term anoxia. Mutations in genes encoding components of AMPK (aak-2, aakb-1, aakb-2, aakg-2 suppress the environmentally and genetically induced long-term anoxia survival phenotype. We further determine that there is a correlation between the animals that survive long-term anoxia and increased levels of carminic acid staining, which is a fluorescent dye that incorporates in with carbohydrates such as glycogen.We conclude that small changes in growth conditions such as increased temperature and food source can influence the physiology of the animal thus affecting the responses to stress such as anoxia. Furthermore, this supports the idea that metformin should be further investigated as a therapeutic tool for treatment of oxygen-deprived tissues. Finally, the capacity for an animal to survive long bouts of severe oxygen deprivation is likely dependent on specific subunits of the heterotrimeric

  7. Short-term calorie restriction improves glucose homeostasis in old rats: involvement of AMPK.

    Science.gov (United States)

    Pires, Rogério C; Souza, Eder E; Vanzela, Emerielle C; Ribeiro, Rosane A; Silva-Santos, Júnia C; Carneiro, Everardo M; Boschero, Antonio C; Amaral, Maria Esméria C

    2014-08-01

    The occurrence of metabolic disorders, such as diabetes, obesity, atherosclerosis, and hypertension, increases with age. Inappropriate food intake, when combined with genetic and hormonal factors, can trigger the occurrence of these diseases in aged organisms. This study investigated whether short-term calorie restriction (CR; 40% of the intake of control animals (CTL) for 21 days) benefits 1-year-old (CR1yr) and 2-year-old (CR2yr) Wistar rats, with regard to insulin secretion and action. Plasma insulin and the insulin secreted by isolated islets were measured with radioimmunoassay, and the insulin sensitivity of peripheral tissues was assessed with the intraperitoneal glucose tolerance test (IPGTT), intraperitoneal insulin tolerance test, and hepatic and muscle adenosine monophosphate-activated protein kinase (AMPK) phosphorylation measurements. Body weight, epididymal fat pad, epididymal fat pad/body weight index, plasma glucose, and insulin were lower in the CR1yr than in the control (CTL1yr) rats. Serum cholesterol, triglycerides, and protein, as well as hepatic and muscle glycogen content, were similar between the CR and CTL groups. The IPGTT was higher in CR2yr and CTL2yr rats than in CR1yr and CTL1yr rats, and insulin sensitivity was higher in CR1yr and CR2yr rats than in their respective CTLs. This was associated with an increase in hepatic and muscle AMPK phosphorylation. No differences in glucose-induced insulin secretion in the isolated islets were observed between CRs and their respective CTL rats. In conclusion, short-term calorie restriction provoked more severe alterations in CR1yr than CR2yr rats. The normoglycemia observed in both CR groups seems to be due to an increase in insulin sensitivity, with the involvement of liver and muscle AMPK.

  8. Resveratrol induces vascular smooth muscle cell differentiation through stimulation of SirT1 and AMPK.

    Directory of Open Access Journals (Sweden)

    Anne Marie Thompson

    Full Text Available Phenotypic plasticity in vascular smooth muscle cells (VSMC is necessary for vessel maintenance, repair and adaptation to vascular changes associated with aging. De-differentiated VSMC contribute to pathologies including atherosclerosis and intimal hyperplasia. As resveratrol has been reported to have cardio- protective effects, we investigated its role in VSMC phenotypic modulation. We demonstrated the novel finding that resveratrol promoted VSMC differentiation as measured by contractile protein expression, contractile morphology and contraction in collagen gels. Resveratrol induced VSMC differentiation through stimulation of SirT1 and AMPK. We made the novel finding that low or high dose resveratrol had an initially different mechanism on induction of differentiation. We found that low dose resveratrol stimulated differentiation through SirT1-mediated activation of AKT, whereas high dose resveratrol stimulated differentiation through AMPK-mediated inhibition of the mTORC1 pathway, allowing activation of AKT. The health effects of resveratrol in cardiovascular diseases, cancer and longevity are an area of active research. We have demonstrated a supplemental avenue where-by resveratrol may promote health by maintaining and enhancing plasticity of the vasculature.

  9. 6-Phosphogluconate dehydrogenase links oxidative PPP, lipogenesis and tumour growth by inhibiting LKB1-AMPK signalling.

    Science.gov (United States)

    Lin, Ruiting; Elf, Shannon; Shan, Changliang; Kang, Hee-Bum; Ji, Quanjiang; Zhou, Lu; Hitosugi, Taro; Zhang, Liang; Zhang, Shuai; Seo, Jae Ho; Xie, Jianxin; Tucker, Meghan; Gu, Ting-Lei; Sudderth, Jessica; Jiang, Lei; Mitsche, Matthew; DeBerardinis, Ralph J; Wu, Shaoxiong; Li, Yuancheng; Mao, Hui; Chen, Peng R; Wang, Dongsheng; Chen, Georgia Zhuo; Hurwitz, Selwyn J; Lonial, Sagar; Arellano, Martha L; Khoury, Hanna J; Khuri, Fadlo R; Lee, Benjamin H; Lei, Qunying; Brat, Daniel J; Ye, Keqiang; Boggon, Titus J; He, Chuan; Kang, Sumin; Fan, Jun; Chen, Jing

    2015-11-01

    The oxidative pentose phosphate pathway (PPP) contributes to tumour growth, but the precise contribution of 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in this pathway, to tumorigenesis remains unclear. We found that suppression of 6PGD decreased lipogenesis and RNA biosynthesis and elevated ROS levels in cancer cells, attenuating cell proliferation and tumour growth. 6PGD-mediated production of ribulose-5-phosphate (Ru-5-P) inhibits AMPK activation by disrupting the active LKB1 complex, thereby activating acetyl-CoA carboxylase 1 and lipogenesis. Ru-5-P and NADPH are thought to be precursors in RNA biosynthesis and lipogenesis, respectively; thus, our findings provide an additional link between the oxidative PPP and lipogenesis through Ru-5-P-dependent inhibition of LKB1-AMPK signalling. Moreover, we identified and developed 6PGD inhibitors, physcion and its derivative S3, that effectively inhibited 6PGD, cancer cell proliferation and tumour growth in nude mice xenografts without obvious toxicity, suggesting that 6PGD could be an anticancer target.

  10. Suppression of Rho-kinase 1 is responsible for insulin regulation of the AMPK/SREBP-1c pathway in skeletal muscle cells exposed to palmitate.

    Science.gov (United States)

    Tang, Sunyinyan; Wu, Wenjun; Tang, Wenjuan; Ge, Zhijuan; Wang, Hongdong; Hong, Ting; Zhu, Dalong; Bi, Yan

    2017-07-01

    Clinical and experimental data suggest that early insulin therapy could reduce lipotoxicity in subjects and animal models with type 2 diabetes mellitus. However, the underlying mechanisms need to be clarified. Sterol regulatory element-binding protein 1c (SREBP-1c), which is negatively regulated by AMP-activated protein kinase (AMPK), plays a critical role in lipotoxicity and insulin resistance in skeletal muscle cells. Here, we investigated the effect and molecular mechanism of insulin intervention on the AMPK/SREBP-1c pathway in skeletal muscle cells with chronic exposure to palmitic acid (PA). Male C57BL/6 mice were fed with a high-fat diet for 12 weeks and were then treated with insulin, AMPK inhibitor, or metformin. L6 myotubes incubated with palmitic acid (PA) were treated with insulin or metformin. Dominant-negative AMPKα2 (DN-AMPKα2) lentivirus, AMPKα2 siRNA, or Rho-kinase 1 (ROCK1) siRNA were transfected into PA-treated L6 myotubes. We found that the ability of PA to stimulate SREBP-1c and inhibit AMPK was reversed by insulin in L6 cells. Moreover, DN-AMPKα2 lentivirus and AMPKα2 siRNA were transfected into PA-treated L6 myotubes, and the decrease in SREBP-1c expression caused by insulin was blocked by AMPK inhibition independent of the phosphatidylinositol-4,5-biphosphate-3-kinase (PI3K)/AKT pathway. The serine/threonine kinase Rho-kinase (ROCK) 1, a downstream effector of the small G protein RhoA, was activated by PA. Interestingly, knockdown of ROCK1 by siRNA blocked the downregulation of AMPK phosphorylation under PA-treated L6 myotubes, which indicated that ROCK1 mediated the effect of insulin action on AMPK. Our study indicated that insulin reduced lipotoxicity via ROCK1 and then improved AMPK/SREBP-1c signaling in skeletal muscle under PA-induced insulin resistance.

  11. G9a Inhibition Induces Autophagic Cell Death via AMPK/mTOR Pathway in Bladder Transitional Cell Carcinoma.

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    Feng Li

    Full Text Available G9a has been reported to highly express in bladder transitional cell carcinoma (TCC and G9a inhibition significantly attenuates cell proliferation, but the underlying mechanism is not fully understood. The present study aimed at examining the potential role of autophagy in the anti-proliferation effect of G9a inhibition on TCC T24 and UMUC-3 cell lines in vitro. We found that both pharmaceutical and genetical G9a inhibition significantly attenuated cell proliferation by MTT assay, Brdu incorporation assay and colony formation assay. G9a inhibition induced autophagy like morphology as determined by transmission electron microscope and LC-3 fluorescence assay. In addition, autophagy flux was induced by G9a inhibition in TCC cells, as determined by p62 turnover assay and LC-3 turnover assay. The autophagy induced positively contributed to the inhibition of cell proliferation because the growth attenuation capacity of G9a inhibition was reversed by autophagy inhibitors 3-MA. Mechanically, AMPK/mTOR pathway was identified to be involved in the regulation of G9a inhibition induced autophagy. Intensively activating mTOR by Rheb overexpression attenuated autophagy and autophagic cell death induced by G9a inhibition. In addition, pre-inhibiting AMPK by Compound C attenuated autophagy together with the anti-proliferation effect induced by G9a inhibition while pre-activating AMPK by AICAR enhanced them. In conclusion, our results indicate that G9a inhibition induces autophagy through activating AMPK/mTOR pathway and the autophagy induced positively contributes to the inhibition of cell proliferation in TCC cells. These findings shed some light on the functional role of G9a in cell metabolism and suggest that G9a might be a therapeutic target in bladder TCC in the future.

  12. The AMPK enzyme-complex: From the regulation of cellular energy homeostasis to a possible new molecular target in the management of chronic inflammatory disorders

    NARCIS (Netherlands)

    Antonioli, Luca; Colucci, Rocchina; Pellegrini, Carolina; Giustarini, Giulio; Sacco, Deborah; Tirotta, Erika; Caputi, Valentina; Marsilio, Ilaria; Giron, Maria Cecilia; Németh, Zoltán H; Blandizzi, Corrado; Fornai, Matteo

    2016-01-01

    Introduction: Adenosine monophosphate-activated protein kinase (AMPK), known as an enzymatic complex that regulates the energetic metabolism, is emerging as a pivotal enzyme and enzymatic pathway involved in the regulation of immune homeostatic networks. It is also involved in the molecular

  13. Genetic disruption of AMPK signaling abolishes both contraction- and insulin-stimulated TBC1D1 phosphorylation and 14-3-3 binding in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Pehmøller, Christian; Treebak, Jonas Thue; Birk, Jesper Bratz

    2009-01-01

    TBC1D1 is a Rab-GTPase-activating protein (GAP) known to be phosphorylated in response to insulin, growth factors, pharmacological agonists that activate 5'-AMP-activated protein kinase (AMPK), and muscle contraction. Silencing TBC1D1 in L6 muscle cells by siRNA increases insulin-stimulated GLUT4...... contraction increases 14-3-3 binding to TBC1D1 as well as phosphorylation of Ser(237) and Thr(596) in an AMPK-dependent manner. AMPK activation by AICAR induced similar Ser(237) and Thr(596) phosphorylation of, and 14-3-3 binding to, TBC1D1 as muscle contraction. Insulin did not increase Ser(237...... translocation, and overexpression of TBC1D1 in 3T3-L1 adipocytes with low endogenous TBC1D1 expression inhibits insulin-stimulated GLUT4 translocation, suggesting a role of TBC1D1 in regulating GLUT4 translocation. Aiming to unravel the regulation of TBC1D1 during contraction and the potential role of AMPK...

  14. Adiponectin concentration is associated with muscle insulin sensitivity, AMPK phosphorylation and ceramide content in skeletal muslce of men, but not women

    DEFF Research Database (Denmark)

    Høeg, Louise Dalgas; Sjøberg, Kim Anker; Lundsgaard, Annemarie

    2013-01-01

    . These associations suggest that the insulin-sensitizing effect of adiponectin on human male skeletal muscles may be mediated via AdipoR1 to activation of AMPK leading to lowering of ceramide content. The lower skeletal muscle AdipoR1 protein expression and lower expression of adiponectin sensitive type II muscle...

  15. Resveratrol engages AMPK to attenuate ERK and mTOR signaling in sensory neurons and inhibits incision-induced acute and chronic pain

    Directory of Open Access Journals (Sweden)

    Tillu Dipti V

    2012-01-01

    Full Text Available Abstract Background Despite advances in our understanding of basic mechanisms driving post-surgical pain, treating incision-induced pain remains a major clinical challenge. Moreover, surgery has been implicated as a major cause of chronic pain conditions. Hence, more efficacious treatments are needed to inhibit incision-induced pain and prevent the transition to chronic pain following surgery. We reasoned that activators of AMP-activated protein kinase (AMPK may represent a novel treatment avenue for the local treatment of incision-induced pain because AMPK activators inhibit ERK and mTOR signaling, two important pathways involved in the sensitization of peripheral nociceptors. Results To test this hypothesis we used a potent and efficacious activator of AMPK, resveratrol. Our results demonstrate that resveratrol profoundly inhibits ERK and mTOR signaling in sensory neurons in a time- and concentration-dependent fashion and that these effects are mediated by AMPK activation and independent of sirtuin activity. Interleukin-6 (IL-6 is thought to play an important role in incision-induced pain and resveratrol potently inhibited IL-6-mediated signaling to ERK in sensory neurons and blocked IL-6-mediated allodynia in vivo through a local mechanism of action. Using a model of incision-induced allodynia in mice, we further demonstrate that local injection of resveratrol around the surgical wound strongly attenuates incision-induced allodynia. Intraplantar IL-6 injection and plantar incision induces persistent nociceptive sensitization to PGE2 injection into the affected paw after the resolution of allodynia to the initial stimulus. We further show that resveratrol treatment at the time of IL-6 injection or plantar incision completely blocks the development of persistent nociceptive sensitization consistent with the blockade of a transition to a chronic pain state by resveratrol treatment. Conclusions These results highlight the importance of signaling

  16. Globular adiponectin ameliorates metabolic insulin resistance via AMPK-mediated restoration of microvascular insulin responses

    Science.gov (United States)

    Zhao, Lina; Fu, Zhuo; Wu, Jing; Aylor, Kevin W; Barrett, Eugene J; Cao, Wenhong; Liu, Zhenqi

    2015-01-01

    Abstract Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance, and microvasculature plays a critical role in the regulation of insulin action in muscle. Here we tested whether adiponectin replenishment could improve metabolic insulin sensitivity in male rats fed a high-fat diet (HFD) via the modulation of microvascular insulin responses. Male Sprague–Dawley rats were fed either a HFD or low-fat diet (LFD) for 4 weeks. Small resistance artery myograph changes in tension, muscle microvascular recruitment and metabolic response to insulin were determined. Compared with rats fed a LFD, HFD feeding abolished the vasodilatory actions of globular adiponectin (gAd) and insulin on pre-constricted distal saphenous arteries. Pretreatment with gAd improved insulin responses in arterioles isolated from HFD rats, which was blocked by AMP-activated protein kinase (AMPK) inhibition. Similarly, HFD abolished microvascular responses to either gAd or insulin and decreased insulin-stimulated glucose disposal by ∼60%. However, supplementing gAd fully rescued insulin’s microvascular action and significantly improved the metabolic responses to insulin in HFD male rats and these actions were abolished by inhibition of either AMPK or nitric oxide production. We conclude that HFD induces vascular adiponectin and insulin resistance but gAd administration can restore vascular insulin responses and improve insulin’s metabolic action via an AMPK- and nitric oxide-dependent mechanism in male rats. Key points Adiponectin is an adipokine with anti-inflammatory and anti-diabetic properties. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance in obesity and diabetes. Insulin resistance is present in muscle microvasculature and this may contribute to decreased insulin delivery to, and action in, muscle. In this study we examined whether adiponectin ameliorates metabolic insulin resistance by affecting muscle

  17. Globular adiponectin ameliorates metabolic insulin resistance via AMPK-mediated restoration of microvascular insulin responses.

    Science.gov (United States)

    Zhao, Lina; Fu, Zhuo; Wu, Jing; Aylor, Kevin W; Barrett, Eugene J; Cao, Wenhong; Liu, Zhenqi

    2015-09-01

    Adiponectin is an adipokine with anti-inflammatory and anti-diabetic properties. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance in obesity and diabetes. Insulin resistance is present in muscle microvasculature and this may contribute to decreased insulin delivery to, and action in, muscle. In this study we examined whether adiponectin ameliorates metabolic insulin resistance by affecting muscle microvascular recruitment. We demonstrated that a high-fat diet induces vascular adiponectin and insulin resistance but globular adiponectin administration can restore vascular insulin responses and improve insulin's metabolic action via an AMPK- and nitric oxide-dependent mechanism. This suggests that globular adiponectin might have a therapeutic potential for improving insulin resistance and preventing cardiovascular complications in patients with diabetes via modulation of microvascular insulin responses. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance, and microvasculature plays a critical role in the regulation of insulin action in muscle. Here we tested whether adiponectin replenishment could improve metabolic insulin sensitivity in male rats fed a high-fat diet (HFD) via the modulation of microvascular insulin responses. Male Sprague-Dawley rats were fed either a HFD or low-fat diet (LFD) for 4 weeks. Small resistance artery myograph changes in tension, muscle microvascular recruitment and metabolic response to insulin were determined. Compared with rats fed a LFD, HFD feeding abolished the vasodilatory actions of globular adiponectin (gAd) and insulin on pre-constricted distal saphenous arteries. Pretreatment with gAd improved insulin responses in arterioles isolated from HFD rats, which was blocked by AMP-activated protein kinase (AMPK) inhibition. Similarly, HFD abolished microvascular responses to either gAd or insulin and decreased insulin-stimulated glucose disposal by

  18. Coinjection of CCK and leptin reduces food intake via increased CART/TRH and reduced AMPK phosphorylation in the hypothalamus.

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    Akieda-Asai, Sayaka; Poleni, Paul-Emile; Date, Yukari

    2014-06-01

    CCK and leptin are anorectic hormones produced in the small intestine and white adipose tissue, respectively. Investigating how these hormones act together as an integrated anorectic signal is important for elucidating the mechanisms by which energy balance is maintained. We found here that coadministration of subthreshold CCK and leptin, which individually have no effect on feeding, dramatically reduced food intake in rats. Phosphorylation of AMP-activated protein kinase (AMPK) in the hypothalamus significantly decreased after coinjection of CCK and leptin. In addition, coadministration of these hormones significantly increased mRNA levels of anorectic cocaine- and amphetamine-regulated transcript (CART) and thyrotropin-releasing hormone (TRH) in the hypothalamus. The interactive effect of CCK and leptin on food intake was abolished by intracerebroventricular preadministration of the AMPK activator AICAR or anti-CART/anti-TRH antibodies. These findings indicate that coinjection of CCK and leptin reduces food intake via reduced AMPK phosphorylation and increased CART/TRH in the hypothalamus. Furthermore, by using midbrain-transected rats, we investigated the role of the neural pathway from the hindbrain to the hypothalamus in the interaction of CCK and leptin to reduce food intake. Food intake reduction induced by coinjection of CCK and leptin was blocked in midbrain-transected rats. Therefore, the neural pathway from hindbrain to hypothalamus plays an important role in transmitting the anorectic signals provided by coinjection of CCK and leptin. Our findings give further insight into the mechanisms of feeding and energy balance. Copyright © 2014 the American Physiological Society.

  19. Clopidogrel Protects Endothelium by Hindering TNFα-Induced VCAM-1 Expression through CaMKKβ/AMPK/Nrf2 Pathway

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    Huabing Yang

    2016-01-01

    Full Text Available Clopidogrel (INN, an oral antiplatelet drug, has been revealed to have a number of biological properties, for instance, anti-inflammation and antioxidation. Oxidative stress plays an imperative role in inflammation, diabetes mellitus, atherosclerosis, and cancer. In the present study, human aortic endothelial cells (HAECs were employed to explore the anti-inflammatory activity of INN. INN reduced TNFα-induced reactive oxygen species (ROS generation and time-dependently prompted the expression and activity of heme oxygenase 1 (HO-1. Cellular glutathione (GSH levels were augmented by INN. shHO-1 blocked the INN suppression of TNFα-induced HL-60 cell adhesion. The CaMKKβ/AMPK pathway and Nrf2 transcriptional factor were implicated in the induction of HO-1 by INN. Additionally, TNFα dramatically augmented VCAM-1 expression at protein and mRNA levels. INN treatment strikingly repressed TNFα-induced expression of VCAM-1 and HL-60 cell adhesion. Compound C, an AMPK inhibitor, and shNrf2 abolished TNFα-induced expression of VCAM-1 and HL-60 cell adhesion. Our data suggest that INN diminishes TNFα-stimulated VCAM-1 expression at least in part via HO-1 induction, which is CaMKKβ/AMPK pathway-dependent.

  20. Metformin prevents endoplasmic reticulum stress-induced apoptosis through AMPK-PI3K-c-Jun NH2 pathway

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    Jung, T.W.; Lee, M.W.; Lee, Y.-J.; Kim, S.M.

    2012-01-01

    Type 2 diabetes mellitus is thought to be partially associated with endoplasmic reticulum (ER) stress toxicity on pancreatic beta cells and the result of decreased insulin synthesis and secretion. In this study, we showed that a well-known insulin sensitizer, metformin, directly protects against dysfunction and death of ER stress-induced NIT-1 cells (a mouse pancreatic beta cell line) via AMP-activated protein kinase (AMPK) and phosphatidylinositol-3 (PI3) kinase activation. We also showed that exposure of NIT-1 cells to metformin (5mM) increases cellular resistance against ER stress-induced NIT-1 cell dysfunction and death. AMPK and PI3 kinase inhibitors abolished the effect of metformin on cell function and death. Metformin-mediated protective effects on ER stress-induced apoptosis were not a result of an unfolded protein response or the induced inhibitors of apoptotic proteins. In addition, we showed that exposure of ER stressed-induced NIT-1 cells to metformin decreases the phosphorylation of c-Jun NH(2) terminal kinase (JNK). These data suggest that metformin is an important determinant of ER stress-induced apoptosis in NIT-1 cells and may have implications for ER stress-mediated pancreatic beta cell destruction via regulation of the AMPK-PI3 kinase-JNK pathway.

  1. Differentiated mTOR but not AMPK signaling after strength vs endurance exercise in training-accustomed individuals.

    Science.gov (United States)

    Vissing, K; McGee, S L; Farup, J; Kjølhede, T; Vendelbo, M H; Jessen, N

    2013-06-01

    The influence of adenosine mono phosphate (AMP)-activated protein kinase (AMPK) vs Akt-mammalian target of rapamycin C1 (mTORC1) protein signaling mechanisms on converting differentiated exercise into training specific adaptations is not well-established. To investigate this, human subjects were divided into endurance, strength, and non-exercise control groups. Data were obtained before and during post-exercise recovery from single-bout exercise, conducted with an exercise mode to which the exercise subjects were accustomed through 10 weeks of prior training. Blood and muscle samples were analyzed for plasma substrates and hormones and for muscle markers of AMPK and Akt-mTORC1 protein signaling. Increases in plasma glucose, insulin, growth hormone (GH), and insulin-like growth factor (IGF)-1, and in phosphorylated muscle phospho-Akt substrate (PAS) of 160 kDa, mTOR, 70 kDa ribosomal protein S6 kinase, eukaryotic initiation factor 4E, and glycogen synthase kinase 3a were observed after strength exercise. Increased phosphorylation of AMPK, histone deacetylase5 (HDAC5), cAMP response element-binding protein, and acetyl-CoA carboxylase (ACC) was observed after endurance exercise, but not differently from after strength exercise. No changes in protein phosphorylation were observed in non-exercise controls. Endurance training produced an increase in maximal oxygen uptake and a decrease in submaximal exercise heart rate, while strength training produced increases in muscle cross-sectional area and strength. No changes in basal levels of signaling proteins were observed in response to training. The results support that in training-accustomed individuals, mTORC1 signaling is preferentially activated after hypertrophy-inducing exercise, while AMPK signaling is less specific for differentiated exercise.

  2. Berberine inhibits hepatic gluconeogenesis via the LKB1-AMPK-TORC2 signaling pathway in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Jiang, Shu-Jun; Dong, Hui; Li, Jing-Bin; Xu, Li-Jun; Zou, Xin; Wang, Kai-Fu; Lu, Fu-Er; Yi, Ping

    2015-07-07

    To investigate the molecular mechanisms of berberine inhibition of hepatic gluconeogenesis in a diabetic rat model. The 40 rats were randomly divided into five groups. One group was selected as the normal group. In the remaining groups (n = 8 each), the rats were fed on a high-fat diet for 1 mo and received intravenous injection of streptozotocin for induction of the diabetic models. Berberine (156 mg/kg per day) (berberine group) or metformin (184 mg/kg per day) (metformin group) was intragastrically administered to the diabetic rats and 5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside (AICAR) (0.5 mg/kg per day) (AICAR group) was subcutaneously injected to the diabetic rats for 12 wk. The remaining eight diabetic rats served as the model group. Fasting plasma glucose and insulin levels as well as lipid profile were tested. The expressions of proteins were examined by western blotting. The nuclear translocation of CREB-regulated transcription co-activator (TORC)2 was observed by immunohistochemical staining. Berberine improved impaired glucose tolerance and decreased plasma hyperlipidemia. Moreover, berberine decreased fasting plasma insulin and homeostasis model assessment of insulin resistance (HOMA-IR). Berberine upregulated protein expression of liver kinase (LK)B1, AMP-activated protein kinase (AMPK) and phosphorylated AMPK (p-AMPK). The level of phophorylated TORC2 (p-TORC2) protein in the cytoplasm was higher in the berberine group than in the model group, and no significant difference in total TORC2 protein level was observed. Immunohistochemical staining revealed that more TORC2 was localized in the cytoplasm of the berberine group than in the model group. Moreover, berberine treatment downregulated protein expression of the key gluconeogenic enzymes (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) in the liver tissues. Our findings revealed that berberine inhibited hepatic gluconeogenesis via the regulation of the LKB1-AMPK-TORC2

  3. Empagliflozin rescues diabetic myocardial microvascular injury via AMPK-mediated inhibition of mitochondrial fission.

    Science.gov (United States)

    Zhou, Hao; Wang, Shuyi; Zhu, Pingjun; Hu, Shunying; Chen, Yundai; Ren, Jun

    2018-05-01

    Impaired cardiac microvascular function contributes to diabetic cardiovascular complications although effective therapy remains elusive. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor recently approved for treatment of type 2 diabetes, promotes glycosuria excretion and offers cardioprotective actions beyond its glucose-lowering effects. This study was designed to evaluate the effect of empagliflozin on cardiac microvascular injury in diabetes and the underlying mechanism involved with a focus on mitochondria. Our data revealed that empagliflozin improved diabetic myocardial structure and function, preserved cardiac microvascular barrier function and integrity, sustained eNOS phosphorylation and endothelium-dependent relaxation, as well as improved microvessel density and perfusion. Further study suggested that empagliflozin exerted its effects through inhibition of mitochondrial fission in an adenosine monophosphate (AMP)-activated protein kinase (AMPK)-dependent manner. Empagliflozin restored AMP-to-ATP ratio to trigger AMPK activation, suppressed Drp1 S616 phosphorylation, and increased Drp1 S637 phosphorylation, ultimately leading to inhibition of mitochondrial fission. The empagliflozin-induced inhibition of mitochondrial fission preserved cardiac microvascular endothelial cell (CMEC) barrier function through suppressed mitochondrial reactive oxygen species (mtROS) production and subsequently oxidative stress to impede CMEC senescence. Empagliflozin-induced fission loss also favored angiogenesis by promoting CMEC migration through amelioration of F-actin depolymerization. Taken together, these results indicated the therapeutic promises of empagliflozin in the treatment of pathological microvascular changes in diabetes. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Empagliflozin rescues diabetic myocardial microvascular injury via AMPK-mediated inhibition of mitochondrial fission

    Directory of Open Access Journals (Sweden)

    Hao Zhou

    2018-05-01