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Almohawes ZN, El-Kott A, Morsy K, Shati AA, El-Kenawy AE, Khalifa HS, Elsaid FG, Abd-Lateif AEKM, Abu-Zaiton A, Ebealy ER, Abdel-Daim MM, Ghanem RA, Abd-Ella EM. Salidroside inhibits insulin resistance and hepatic steatosis by downregulating miR-21 and subsequent activation of AMPK and upregulation of PPARα in the liver and muscles of high fat diet-fed rats. Arch Physiol Biochem 2024; 130:257-274. [PMID: 35061559 DOI: 10.1080/13813455.2021.2024578] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/15/2021] [Accepted: 12/27/2021] [Indexed: 02/06/2023]
Abstract
This study evaluated if salidroside (SAL) alleviates high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) by downregulating miR-21. Rats (n = 8/group) were treated for 12 weeks as normal diet (control/ND), ND + agmoir negative control (NC) (150 µg/kg), ND + SAL (300 mg/kg), HFD, HFD + SAL, HFD + compound C (an AMPK inhibitor) (200 ng/kg), HFD + SAL + NXT629 (a PPAR-α antagonist) (30 mg/kg), and HFD + SAL + miR-21 agomir (150 µg/kg). SAL improved glucose and insulin tolerance and preserved livers in HFD-fed rats. In ND and HFD-fed rats, SAL reduced levels of serum and hepatic lipids and the hepatic expression of SREBP1, SREBP2, fatty acid (FA) synthase, and HMGCOAR. It also activated hepatic Nrf2 and increased hepatic/muscular activity of AMPK and levels of PPARα. All effects afforded by SAL were prevented by CC, NXT629, and miR-21 agmoir. In conclusion, activation of AMPK and upregulation of PPARα mediate the anti-steatotic effect of SAL.
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Affiliation(s)
- Zakiah N Almohawes
- Biology Department, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Attalla El-Kott
- Biology Department, College of Science, King Khalid University, Abha, Saudi Arabia
- Zoology Department, College of Science, Damanhour University, Damanhour, Egypt
| | - Kareem Morsy
- Biology Department, College of Science, King Khalid University, Abha, Saudi Arabia
- Zoology Department, College of Science, Cairo University, Cairo, Egypt
| | - Ali A Shati
- Biology Department, College of Science, King Khalid University, Abha, Saudi Arabia
| | - Ayman E El-Kenawy
- Pathology Department, College of Medicine, Taif University, Taif, Saudi Arabia
| | - Heba S Khalifa
- Zoology Department, College of Science, Damanhour University, Damanhour, Egypt
| | - Fahmy G Elsaid
- Biology Department, College of Science, King Khalid University, Abha, Saudi Arabia
- Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt
| | | | | | - Eman R Ebealy
- Biology Department, College of Science, King Khalid University, Abha, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Pharmaceutical Sciences Department, Pharmacy Program, Batterjee Medical College, Jeddah, Saudi Arabia
- Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Reham A Ghanem
- Oral Biology Department, Faculty of Oral and Dental Medicine, Delta University for Science and Technology, Gamasa, Egypt
| | - Eman M Abd-Ella
- Zoology Department, College of Science, Fayoum University, Fayoum, Egypt
- Biology Department, College of Science and Art, Al-Baha University, Al-Mandaq, Saudi Arabia
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Peroxisome Proliferator-Activated Receptors as Molecular Links between Caloric Restriction and Circadian Rhythm. Nutrients 2020; 12:nu12113476. [PMID: 33198317 PMCID: PMC7696073 DOI: 10.3390/nu12113476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
The circadian rhythm plays a chief role in the adaptation of all bodily processes to internal and environmental changes on the daily basis. Next to light/dark phases, feeding patterns constitute the most essential element entraining daily oscillations, and therefore, timely and appropriate restrictive diets have a great capacity to restore the circadian rhythm. One of the restrictive nutritional approaches, caloric restriction (CR) achieves stunning results in extending health span and life span via coordinated changes in multiple biological functions from the molecular, cellular, to the whole-body levels. The main molecular pathways affected by CR include mTOR, insulin signaling, AMPK, and sirtuins. Members of the family of nuclear receptors, the three peroxisome proliferator-activated receptors (PPARs), PPARα, PPARβ/δ, and PPARγ take part in the modulation of these pathways. In this non-systematic review, we describe the molecular interconnection between circadian rhythm, CR-associated pathways, and PPARs. Further, we identify a link between circadian rhythm and the outcomes of CR on the whole-body level including oxidative stress, inflammation, and aging. Since PPARs contribute to many changes triggered by CR, we discuss the potential involvement of PPARs in bridging CR and circadian rhythm.
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Sayed AM, Hassanein EH, Salem SH, Hussein OE, Mahmoud AM. Flavonoids-mediated SIRT1 signaling activation in hepatic disorders. Life Sci 2020; 259:118173. [DOI: 10.1016/j.lfs.2020.118173] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/18/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023]
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4
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Li L, Lv H, Jiang Z, Qiao F, Chen L, Zhang M, Du Z. Peroxisomal proliferator‐activated receptor α‐b deficiency induces the reprogramming of nutrient metabolism in zebrafish. J Physiol 2020; 598:4537-4553. [DOI: 10.1113/jp279814] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ling‐Yu Li
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Hong‐Bo Lv
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Zhe‐Yue Jiang
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Fang Qiao
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Li‐Qiao Chen
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Mei‐Ling Zhang
- LANEH School of Life Sciences East China Normal University Shanghai China
| | - Zhen‐Yu Du
- LANEH School of Life Sciences East China Normal University Shanghai China
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5
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Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity. Cells 2020; 9:cells9071708. [PMID: 32708786 PMCID: PMC7407644 DOI: 10.3390/cells9071708] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.
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6
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Li T, Du M, Wang H, Mao X. Milk fat globule membrane and its component phosphatidylcholine induce adipose browning both in vivo and in vitro. J Nutr Biochem 2020; 81:108372. [PMID: 32416448 DOI: 10.1016/j.jnutbio.2020.108372] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 02/12/2020] [Accepted: 03/04/2020] [Indexed: 12/13/2022]
Abstract
The functional induction of brown-like adipocytes in white adipose tissue (WAT) provides a defense against obesity. The aim of this study was to analyze the effects of milk fat globule membrane (MFGM) and its component phosphatidylcholine (PC) on the brown remodeling of WAT. Male C57BL/6 J mice were fed a high-fat diet (HFD) for 8 weeks and then fed HFD for another 8 weeks with MFGM. In vitro studies were performed in C3H10T1/2 pluripotent stem cells, 3T3-L1 pre-adipocytes and differentiated inguinal WAT stromal vascular cells (SVCs) to determine the role of MFGM and PC on the formation of brown-like adipocytes. MFGM decreased fasting glucose and serum insulin levels in HFD-fed mice. MFGM improved glucose tolerance and insulin sensitivity, and induced browning of inguinal WAT. MFGM and its component PC stimulated transformation of brown-like adipocytes in C3H10T1/2 pluripotent stem cells, 3T3-L1 adipocytes and SVCs by increasing the protein expression of UCP1, PGC-1α, PRDM16 as well as the mRNA expression of other thermogenic genes and beige cell markers. MFGM and PC also increased mitochondrial DNA (mtDNA) copy number, mitochondrial density and oxygen consumption rate and up-regulated the mRNA expression of mitochondria-biogenesis-related genes in vitro. PPARα inhibitor GW6471 treatment or knockdown of PPARα using lentivirus-expressing shRNA inhibited the PC-induced increase in the protein expression of UCP1, PGC-1α and PRDM16 in C3H10T1/2 pluripotent stem cells and 3T3-L1 adipocytes, indicating the potential role of PPARα in PC-mediated brown-like adipocyte formation. In conclusion, MFGM and milk PC induced adipose browning, which has major protective effects against obesity and metabolic dysfunction.
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Affiliation(s)
- Tiange Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; College of Food Science and Nutritional Engineering, Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Min Du
- Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA
| | - Hanning Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Xueying Mao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; College of Food Science and Nutritional Engineering, Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, China Agricultural University, Beijing 100083, China.
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DiNicolantonio JJ, McCarty M, OKeefe J. Astaxanthin plus berberine: a nutraceutical strategy for replicating the benefits of a metformin/fibrate regimen in metabolic syndrome. Open Heart 2019; 6:e000977. [PMID: 31565232 PMCID: PMC6744071 DOI: 10.1136/openhrt-2018-000977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/04/2019] [Indexed: 11/04/2022] Open
Affiliation(s)
- James J DiNicolantonio
- Department of Preventive Cardiology, Mid America Heart Institute, Kansas City, Kansas, USA
| | | | - James OKeefe
- Saint Luke's Mid America Heart Institute, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Comparative Evaluation of Gemcabene and Peroxisome Proliferator-Activated Receptor Ligands in Transcriptional Assays of Peroxisome Proliferator-Activated Receptors: Implication for the Treatment of Hyperlipidemia and Cardiovascular Disease. J Cardiovasc Pharmacol 2019; 72:3-10. [PMID: 29621036 PMCID: PMC6039382 DOI: 10.1097/fjc.0000000000000580] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Gemcabene, a late-stage clinical candidate, has shown efficacy for LDL-C, non-HDL cholesterol, apoB, triglycerides, and hsCRP reduction, all risk factors for cardiovascular disease. In rodents, gemcabene showed changes in targets, including apoC-III, apoA-I, peroxisomal enzymes, considered regulated through peroxisome proliferator-activated receptor (PPAR) gene activation, suggesting a PPAR-mediated mechanism of action for the observed hypolipidemic effects observed in rodents and humans. In the current study, the gemcabene agonist activity against PPAR subtypes of human, rat, and mouse were compared with known lipid lowering PPAR activators. Surprisingly, gemcabene showed no or little PPAR-α transactivation compared with reference agonists, which showed concentration-dependent transactivation against human PPAR-α of 2.4- to 30-fold (fenofibric acid), 17-fold (GW590735), and 2.3- to 25-fold (WY-14643). These agents also showed robust transactivation of mouse and rat PPAR-α in a concentration-dependent manner. The known PPAR-δ agonists, GW1516, L165041, and GW0742, showed potent agonist activity against human, mouse, and rat receptors (ranging from 165- to 396-fold). By contrast, gemcabene at the highest concentration tested (300 μM) showed no response in mouse and rat and a marginal response against human PPAR-δ receptors (3.2-fold). For PPAR-γ, gemcabene showed no agonist activity against all 3 species at 100 μM and marginal activity (3.6- to 5-fold) at 300 μM. By contrast, the known agonists, rosiglitazone, indomethacin, and muraglitazar showed strong activation against the mouse, rat, and human PPAR-γ receptors. No clear antagonist activity was observed with gemcabene against any PPAR subtypes for all 3 species over a wide range of concentrations. In summary, the transactivation studies rule out gemcabene as a direct agonist or antagonist of PPAR-α, PPAR-γ, and PPAR-δ receptors of these 3 species. These data suggest that the peroxisomal effects observed in rodents and the lipid regulating effects observed in rodents and humans are not related to a direct activation of PPAR receptors by gemcabene.
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Wang H, Mao X, Du M. Phytanic acid activates PPARα to promote beige adipogenic differentiation of preadipocytes. J Nutr Biochem 2019; 67:201-211. [PMID: 30951974 DOI: 10.1016/j.jnutbio.2019.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/23/2019] [Accepted: 02/28/2019] [Indexed: 11/30/2022]
Abstract
A better understanding of the mechanisms of beige and brown adipogenesis is needed for developing strategies to prevent and treat obesity and associated metabolic disorders. Phytanic acid (PA) exists in a wide range of foods, especially in milk fat and marine foods, but its effects on obesity and beige adipogenesis remain poorly defined. The objective is to investigate the effects and regulatory mechanisms of PA in the beige adipogenesis. In 3T3-L1 preadipocytes, PA elevated the expression of brown adipogenic markers, suggesting that PA promotes beige adipogenic differentiation in committed adipogenic cells. In uncommitted C3H10T1/2 cells, while PA increased PGC1α expression, it did not increase brown adipogenic regulators PRDM16 or UCP1 expression, suggesting that PA had no significant effects on brown adipocyte commitment. PA also enhanced mitochondrial biogenesis and oxygen consumption. Promotion of both mitochondriogenesis and beige adipogenic differentiation were blocked by using PPARα antagonist or with Pparα knockdown, showing that PA-mediated beige/brown adipogenic differentiation is dependent on PPARα. Additionally, the PA-regulated effect is independent on β3-adrenergic receptor. Taken together, PA promotes beige adipogenic differentiation, but not the commitment of progenitor cells to the brown adipocyte lineage. PPARα is a key mediator during PA-induced beige/brown adipogenic differentiation.
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Affiliation(s)
- Hanning Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100194, China; College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Xueying Mao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100194, China; College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Min Du
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100194, China; Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA.
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10
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Ratman D, Mylka V, Bougarne N, Pawlak M, Caron S, Hennuyer N, Paumelle R, De Cauwer L, Thommis J, Rider MH, Libert C, Lievens S, Tavernier J, Staels B, De Bosscher K. Chromatin recruitment of activated AMPK drives fasting response genes co-controlled by GR and PPARα. Nucleic Acids Res 2016; 44:10539-10553. [PMID: 27576532 PMCID: PMC5159533 DOI: 10.1093/nar/gkw742] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/08/2016] [Accepted: 08/15/2016] [Indexed: 12/21/2022] Open
Abstract
Adaptation to fasting involves both Glucocorticoid Receptor (GRα) and Peroxisome Proliferator-Activated Receptor α (PPARα) activation. Given both receptors can physically interact we investigated the possibility of a genome-wide cross-talk between activated GR and PPARα, using ChIP- and RNA-seq in primary hepatocytes. Our data reveal extensive chromatin co-localization of both factors with cooperative induction of genes controlling lipid/glucose metabolism. Key GR/PPAR co-controlled genes switched from transcriptional antagonism to cooperativity when moving from short to prolonged hepatocyte fasting, a phenomenon coinciding with gene promoter recruitment of phosphorylated AMP-activated protein kinase (AMPK) and blocked by its pharmacological inhibition. In vitro interaction studies support trimeric complex formation between GR, PPARα and phospho-AMPK. Long-term fasting in mice showed enhanced phosphorylation of liver AMPK and GRα Ser211. Phospho-AMPK chromatin recruitment at liver target genes, observed upon prolonged fasting in mice, is dampened by refeeding. Taken together, our results identify phospho-AMPK as a molecular switch able to cooperate with nuclear receptors at the chromatin level and reveal a novel adaptation mechanism to prolonged fasting.
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Affiliation(s)
- Dariusz Ratman
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
| | - Viacheslav Mylka
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
| | - Nadia Bougarne
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
| | - Michal Pawlak
- UNIV LILLE, 59000 Lille, France.,INSERM UMR 1011, 59000 Lille, France.,European Genomic Institute for Diabetes E.G.I.D., FR 3508, 59000 Lille, France.,Institut Pasteur de Lille, 59000 Lille, France
| | - Sandrine Caron
- UNIV LILLE, 59000 Lille, France.,INSERM UMR 1011, 59000 Lille, France.,European Genomic Institute for Diabetes E.G.I.D., FR 3508, 59000 Lille, France.,Institut Pasteur de Lille, 59000 Lille, France
| | - Nathalie Hennuyer
- UNIV LILLE, 59000 Lille, France.,INSERM UMR 1011, 59000 Lille, France.,European Genomic Institute for Diabetes E.G.I.D., FR 3508, 59000 Lille, France.,Institut Pasteur de Lille, 59000 Lille, France
| | - Réjane Paumelle
- UNIV LILLE, 59000 Lille, France.,INSERM UMR 1011, 59000 Lille, France.,European Genomic Institute for Diabetes E.G.I.D., FR 3508, 59000 Lille, France.,Institut Pasteur de Lille, 59000 Lille, France
| | - Lode De Cauwer
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
| | - Jonathan Thommis
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
| | - Mark H Rider
- de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Claude Libert
- Inflammation Research Center, VIB, 9052 Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Sam Lievens
- Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.,Receptor Research Laboratories, Cytokine Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium
| | - Jan Tavernier
- Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.,Receptor Research Laboratories, Cytokine Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium
| | - Bart Staels
- UNIV LILLE, 59000 Lille, France.,INSERM UMR 1011, 59000 Lille, France.,European Genomic Institute for Diabetes E.G.I.D., FR 3508, 59000 Lille, France.,Institut Pasteur de Lille, 59000 Lille, France.,CHU Lille, Department of Biology, 59000 Lille, France
| | - Karolien De Bosscher
- Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, 9000 Ghent, Belgium .,Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
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Xylazine Activates Adenosine Monophosphate-Activated Protein Kinase Pathway in the Central Nervous System of Rats. PLoS One 2016; 11:e0153169. [PMID: 27049320 PMCID: PMC4822969 DOI: 10.1371/journal.pone.0153169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/24/2016] [Indexed: 01/03/2023] Open
Abstract
Xylazine is a potent analgesic extensively used in veterinary and animal experimentation. Evidence exists that the analgesic effect can be inhibited using adenosine 5'-monophosphate activated protein kinase (AMPK) inhibitors. Considering this idea, the aim of this study was to investigate whether the AMPK signaling pathway is involved in the central analgesic mechanism of xylazine in the rat. Xylazine was administrated via the intraperitoneal route. Sprague-Dawley rats were sacrificed and the cerebral cortex, cerebellum, hippocampus, thalamus and brainstem were collected for determination of liver kinase B1 (LKB1) and AMPKα mRNA expression using quantitative real-time polymerase chain reaction (qPCR), and phosphorylated LKB1 and AMPKα levels using western blot. The results of our study showed that compared with the control group, xylazine induced significant increases in AMPK activity in the cerebral cortex, hippocampus, thalamus and cerebellum after rats received xylazine (P < 0.01). Increased AMPK activities were accompanied with increased phosphorylation levels of LKB1 in corresponding regions of rats. The protein levels of phosphorylated LKB1 and AMPKα in these regions returned or tended to return to control group levels. However, in the brainstem, phosphorylated LKB1 and AMPKα protein levels were decreased by xylazine compared with the control (P < 0.05). In conclusion, our data indicates that xylazine alters the activities of LKB1 and AMPK in the central nervous system of rats, which suggests that xylazine affects the regulatory signaling pathway of the analgesic mechanism in the rat brain.
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12
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Inhibition of cereblon by fenofibrate ameliorates alcoholic liver disease by enhancing AMPK. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2662-70. [DOI: 10.1016/j.bbadis.2015.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/10/2015] [Accepted: 09/23/2015] [Indexed: 12/20/2022]
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13
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Kim MS, Lee KT, Iseli TJ, Hoy AJ, George J, Grewal T, Roufogalis BD. Compound K modulates fatty acid-induced lipid droplet formation and expression of proteins involved in lipid metabolism in hepatocytes. Liver Int 2013; 33:1583-93. [PMID: 23998390 DOI: 10.1111/liv.12287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 07/24/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS A key factor in the development of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) is hepatic steatosis. Incubation of human hepatic cells with free fatty acids (FFAs) causes accumulation of neutral lipids in lipid droplets (LDs) and serves as a model for hepatic steatosis. Ginsenosides, active constituents of ginsengs, have demonstrated beneficial effects in various pharmacological areas, including diabetes, however their effect on lipid accumulation in hepatocytes remains unclear. Here, we examine the effect of compound K (ComK), an active metabolite of ginsenosides, on the regulation of LD formation and on the expression of proteins involved in lipid homeostasis in hepatocytes. METHODS HuH7 cells were pretreated with ComK, followed by lipid loading with FFA. LDs were visualized using Oil Red O staining and immunohistochemistry for the LD-related protein PLIN2. Triglyceride levels were determined in isolated LDs. The expression of proteins involved in lipid homeostasis was examined by Western blotting. RESULTS Treatment with ComK significantly decreased LD formation in FFA-loaded HuH7 cells and increased phosphorylation levels of AMPK, and its substrate ACC. ComK also increased protein expression of peroxisome proliferator-activated receptor-α (PPAR-α) and acyl-CoA oxidase (ACOX1) together with elevated activity of a PPAR-α response element reporter construct. These effects were inhibited by the PPAR-α antagonist MK886. CONCLUSIONS ComK reduced LD formation and TG accumulation in FFA-loaded hepatocytes, in part by up-regulating AMPK activity and PPAR-α related pathways. These results suggest that ComK may have efficacy for the treatment of hepatic steatosis and associated diseases.
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Affiliation(s)
- Moon-Sun Kim
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW, Australia
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14
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Viswakarma N, Jia Y, Bai L, Gao Q, Lin B, Zhang X, Misra P, Rana A, Jain S, Gonzalez FJ, Zhu YJ, Thimmapaya B, Reddy JK. The Med1 subunit of the mediator complex induces liver cell proliferation and is phosphorylated by AMP kinase. J Biol Chem 2013; 288:27898-911. [PMID: 23943624 DOI: 10.1074/jbc.m113.486696] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mediator, a large multisubunit protein complex, plays a pivotal role in gene transcription by linking gene-specific transcription factors with the preinitiation complex and RNA polymerase II. In the liver, the key subunit of the Mediator complex, Med1, interacts with several nuclear receptors and transcription factors to direct gene-specific transcription. Conditional knock-out of Med1 in the liver showed that hepatocytes lacking Med1 did not regenerate following either partial hepatectomy or treatment with certain nuclear receptor activators and failed to give rise to tumors when challenged with carcinogens. We now report that the adenovirally driven overexpression of Med1 in mouse liver stimulates hepatocyte DNA synthesis with enhanced expression of DNA replication, cell cycle control, and liver-specific genes, indicating that Med1 alone is necessary and sufficient for liver cell proliferation. Importantly, we demonstrate that AMP-activated protein kinase (AMPK), an important cellular energy sensor, interacts with, and directly phosphorylates, Med1 in vitro at serine 656, serine 756, and serine 796. AMPK also phosphorylates Med1 in vivo in mouse liver and in cultured primary hepatocytes and HEK293 and HeLa cells. In addition, we demonstrate that PPARα activators increase AMPK-mediated Med1 phosphorylation in vivo. Inhibition of AMPK by compound C decreased hepatocyte proliferation induced by Med1 and also by the PPARα activators fenofibrate and Wy-14,643. Co-treatment with compound C attenuated PPARα activator-inducible fatty acid β-oxidation in liver. Our results suggest that Med1 phosphorylation by its association with AMPK regulates liver cell proliferation and fatty acid oxidation, most likely as a downstream effector of PPARα and AMPK.
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Affiliation(s)
- Navin Viswakarma
- From the Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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Ambrożewicz E, Augustyniak A, Gęgotek A, Bielawska K, Skrzydlewska E. Black-currant protection against oxidative stress formation. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2013; 76:1293-1306. [PMID: 24283421 DOI: 10.1080/15287394.2013.850762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aim of this study was to investigate the influence of black-currant juice on chronic ethanol-induced oxidative stress and its consequences in liver, brain, and serum of rats. Data demonstrated that administration of black-currant juice to rats improved antioxidant abilities in the examined tissues as evidenced by measurement of activities of Cu,Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GSSG-R), as well as levels of glutathione (GSH) and vitamins C, E, and A. Ethanol intoxication produced a decrease in the activities and levels of the antioxidants just listed, and the decrease was accompanied by a reduction in levels of arachidonic acid (AA) and docosahexaenoic acid (DHA). Further results showed enhanced lipid peroxidation as determined by malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and neuroprostanes and elevated protein levels such as carbonyl groups and dityrosine. Ethanol intoxication altered liver metabolism as evidenced by a decrease in peroxisome proliferator-activated-receptor (PPARα), AMP-dependent protein kinase (AMPK), and nuclear factor kappa B cells (NFκB) and by an increase in tumor necrosis factor (TNF-α) expression. Administration of black-currant juice to ethanol-intoxicated rats exerted an antioxidant response by restoring to normal quantities the antioxidant levels and enzyme activities and prevented lipid and protein oxidative effects. The activities of alanine transaminase and aspartate transaminase, biomarkers of liver damage, returned to normal after black-currant treatment of ethanol-administered animals. In addition, the expression of PPARα, AMPK, TNF-α, and NFκB confirmed the protective effect of the juice. Data thus indicate the extensive antioxidant metabolic effects of black-currant juice that may be beneficial for humans.
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Affiliation(s)
- Ewa Ambrożewicz
- a Department of Analytical Chemistry , Medical University of Bialystok , Bialystok , Poland
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Reichenbach G, Starzinski-Powitz A, Sloane BF, Doll M, Kippenberger S, Bernd A, Kaufmann R, Meissner M. PPARα agonist Wy14643 suppresses cathepsin B in human endothelial cells via transcriptional, post-transcriptional and post-translational mechanisms. Angiogenesis 2012; 16:223-33. [PMID: 23096928 DOI: 10.1007/s10456-012-9314-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 10/12/2012] [Indexed: 10/27/2022]
Abstract
Cathepsin B has been shown to be important in angiogenesis; therefore, understanding its regulation in endothelial cells should provide fundamental information that will aid in the development of new treatment options. Peroxisome proliferator-activated receptors (PPARs) have been shown to have anti-inflammatory, anti-angiogenic and anti-tumorigenic properties. We explored the influence of a PPARα agonist on cathepsin B expression in human endothelial cells. The PPARα agonist, Wy14643, was found to inhibit cathepsin B protein expression. Further studies demonstrated the Wy14643-dependent but PPARα-independent suppression of cathepsin B. This has been previously described for other PPAR agonists. Wy14643 suppressed the accumulation of cathepsin B mRNA, which was accompanied by the selective suppression of a 5'-alternative splice variant. Consistent with these results, luciferase promoter assays and electrophoretic mobility shift analysis demonstrated that the suppression was facilitated by reduced binding of the transcription factors USF1/2 to an E-box within the cathepsin B promoter. Additionally, Wy14643 treatment resulted in a reduction in cathepsin B half-life, suggesting a posttranslational regulatory mechanism. Overall, our results suggest that the PPARα-dependent anti-angiogenic action of Wy14643 seems to be mediated, in part, by Wy14643-dependent but PPARα-independent regulation of cathepsin B expression.
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Affiliation(s)
- Gabi Reichenbach
- Department of Dermatology, Venereology and Allergology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany
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Shulga N, Pastorino JG. Ethanol sensitizes mitochondria to the permeability transition by inhibiting deacetylation of cyclophilin-D mediated by sirtuin-3. J Cell Sci 2010; 123:4117-27. [PMID: 21062897 PMCID: PMC2987442 DOI: 10.1242/jcs.073502] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2010] [Indexed: 12/11/2022] Open
Abstract
Ethanol increases the vulnerability of mitochondria to induction of the mitochondrial permeability transition (MPT). Cyclophilin-D activity enhances the potential for the permeability transition pore (PTP) to open. In the present study, we demonstrate that ethanol and its metabolism sensitize the PTP to opening, in part by increasing the acetylation and activity of cyclophilin-D. This effect of ethanol is mediated by inhibiting the activity of sirtuin-3, an NAD(+) dependent deacetylase that is localized to the mitochondrial matrix. The ethanol-enhanced acetylation of cyclophilin-D also increases the interaction of cyclophilin-D with the adenine nucleotide translocator-1 (ANT-1) and is dependent on ethanol metabolism. Moreover, activation of AMPK, a known positive modulator of sirtuin activity, prevented the ethanol-induced suppression of sirtuin-3 activity and the attendant increase of cyclophilin-D acetylation, activity and association with ANT-1. Additionally, AMPK reactivation of sirtuin-3 prevented the sensitization to the MPT and the enhancement of cell killing by TNF in cells exposed to ethanol.
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Affiliation(s)
- Nataly Shulga
- Department of Molecular Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford, NJ 08084, USA
| | - John G. Pastorino
- Department of Molecular Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford, NJ 08084, USA
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Abstract
Comprehensive studies support the notion that the peroxisome proliferator-activated receptors, (PPARs), PPARα, PPARβ/δ, and PPARγ, regulate cell growth, morphogenesis, differentiation, and homeostasis. Agonists of each PPAR subtype exert their effects similarly or distinctly in different tissues such as liver, muscle, fat, and vessels. It is noteworthy that PPARα or PPARγ agonists have pharmacological effects by modulating the activity of AMPK, which is a key cellular energy sensor. However, the role of AMPK in the metabolic effects of PPAR agonists has not been thoroughly focused. Moreover, AMPK activation by PPAR agonists seems to be independent of the receptor activation. This intriguing action of PPAR agonists may account in part for the mechanistic basis of the therapeutics in the treatment of metabolic disease. In this paper, the effects of PPAR agonists on metabolic functions were summarized with particular reference to their AMPK activity regulation.
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Lee FP, Jen CY, Chang CC, Chou Y, Lin H, Chou CM, Juan SH. Mechanisms of adiponectin-mediated COX-2 induction and protection against iron injury in mouse hepatocytes. J Cell Physiol 2010; 224:837-47. [DOI: 10.1002/jcp.22192] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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