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Julien SG, Kim SY, Brunmeir R, Sinnakannu JR, Ge X, Li H, Ma W, Yaligar J, KN BP, Velan SS, Röder PV, Zhang Q, Sim CK, Wu J, Garcia-Miralles M, Pouladi MA, Xie W, McFarlane C, Han W, Xu F. Narciclasine attenuates diet-induced obesity by promoting oxidative metabolism in skeletal muscle. PLoS Biol 2017; 15:e1002597. [PMID: 28207742 PMCID: PMC5331945 DOI: 10.1371/journal.pbio.1002597] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/23/2017] [Indexed: 12/19/2022] Open
Abstract
Obesity develops when caloric intake exceeds metabolic needs. Promoting energy expenditure represents an attractive approach in the prevention of this fast-spreading epidemic. Here, we report a novel pharmacological strategy in which a natural compound, narciclasine (ncls), attenuates diet-induced obesity (DIO) in mice by promoting energy expenditure. Moreover, ncls promotes fat clearance from peripheral metabolic tissues, improves blood metabolic parameters in DIO mice, and protects these mice from the loss of voluntary physical activity. Further investigation suggested that ncls achieves these beneficial effects by promoting a shift from glycolytic to oxidative muscle fibers in the DIO mice thereby enhancing mitochondrial respiration and fatty acid oxidation (FAO) in the skeletal muscle. Moreover, ncls strongly activates AMPK signaling specifically in the skeletal muscle. The beneficial effects of ncls treatment in fat clearance and AMPK activation were faithfully reproduced in vitro in cultured murine and human primary myotubes. Mechanistically, ncls increases cellular cAMP concentration and ADP/ATP ratio, which further lead to the activation of AMPK signaling. Blocking AMPK signaling through a specific inhibitor significantly reduces FAO in myotubes. Finally, ncls also enhances mitochondrial membrane potential and reduces the formation of reactive oxygen species in cultured myotubes. Narciclasine is a natural compound that attenuates diet-induced obesity in mice by promoting energy expenditure; it also induces a number of beneficial metabolic effects and activates AMPK signaling in skeletal muscle. Obesity results from the imbalance of food intake and energy expenditure. Since the restriction of food intake is difficult and inefficient in maintaining long-term weight loss, enhancing energy expenditure is now an attractive approach in combating obesity. Here, we analysed the role in this process of a natural compound called narciclasine. We showed that narciclasine treatment reduces excess fat accumulation in peripheral metabolic tissues, improves blood metabolic parameters and insulin sensitivity in obese mice, and protects these mice from the loss of voluntary physical activity. Further investigation suggested that narciclasine enhances mitochondrial respiration and fatty acid consumption in the skeletal muscle. In addition, narciclasine strongly activates the AMP-activated protein kinase (AMPK) signaling, which is a central sensor of the cellular energy status and a key player in maintaining energy homeostasis, specifically in the skeletal muscle. Mechanistically, we found that narciclasine increases cAMP concentration and ADP/ATP ratio in muscle cells, which further lead to AMPK activation. Finally, we observed that narciclasine increases mitochondrial membrane potential and reduces the production of reactive oxygen species in muscle cells. Our findings suggest that narciclasine is a natural compound that attenuates diet-induced obesity in mice by promoting energy expenditure.
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MESH Headings
- AMP-Activated Protein Kinases/metabolism
- Adenosine Diphosphate/metabolism
- Adenosine Triphosphate/metabolism
- Amaryllidaceae Alkaloids/pharmacology
- Amaryllidaceae Alkaloids/therapeutic use
- Animals
- Biomarkers/metabolism
- Cell Respiration/drug effects
- Cells, Cultured
- Cyclic AMP/metabolism
- Diet/adverse effects
- Diet, High-Fat
- Energy Metabolism/drug effects
- Enzyme Activation/drug effects
- Fatty Acids/metabolism
- Humans
- Male
- Membrane Potential, Mitochondrial/drug effects
- Mice
- Mice, Inbred C57BL
- Mitochondria/drug effects
- Mitochondria/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Obesity/drug therapy
- Obesity/metabolism
- Oxidation-Reduction/drug effects
- Phenanthridines/pharmacology
- Phenanthridines/therapeutic use
- Physical Conditioning, Animal
- Protective Agents/pharmacology
- Protective Agents/therapeutic use
- Reactive Oxygen Species/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Sofi G. Julien
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Sun-Yee Kim
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Reinhard Brunmeir
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Joanna R. Sinnakannu
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Xiaojia Ge
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Hongyu Li
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Wei Ma
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Jadegoud Yaligar
- Magnetic Resonance Spectroscopy and Metabolic Imaging Group, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Bhanu Prakash KN
- Magnetic Resonance Spectroscopy and Metabolic Imaging Group, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Sendhil S. Velan
- Magnetic Resonance Spectroscopy and Metabolic Imaging Group, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
| | - Pia V. Röder
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Republic of Singapore
| | - Qiongyi Zhang
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Choon Kiat Sim
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Jingyi Wu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Marta Garcia-Miralles
- Translational Laboratory in Genetic Medicine, A*STAR, Singapore, Republic of Singapore
| | - Mahmoud A. Pouladi
- Translational Laboratory in Genetic Medicine, A*STAR, Singapore, Republic of Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Craig McFarlane
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Republic of Singapore
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Republic of Singapore
| | - Feng Xu
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Republic of Singapore
- * E-mail:
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Abstract
In order to ensure normal body function, the human body is dependent on a tight control of its blood glucose levels. This is accomplished by a highly sophisticated network of various hormones and neuropeptides released mainly from the brain, pancreas, liver, intestine as well as adipose and muscle tissue. Within this network, the pancreas represents a key player by secreting the blood sugar-lowering hormone insulin and its opponent glucagon. However, disturbances in the interplay of the hormones and peptides involved may lead to metabolic disorders such as type 2 diabetes mellitus (T2DM) whose prevalence, comorbidities and medical costs take on a dramatic scale. Therefore, it is of utmost importance to uncover and understand the mechanisms underlying the various interactions to improve existing anti-diabetic therapies and drugs on the one hand and to develop new therapeutic approaches on the other. This review summarizes the interplay of the pancreas with various other organs and tissues that maintain glucose homeostasis. Furthermore, anti-diabetic drugs and their impact on signaling pathways underlying the network will be discussed.
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Affiliation(s)
- Pia V Röder
- Metabolism in Human Diseases Unit, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Metabolism in Human Diseases Unit, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore. E-mail: or
| | - Bingbing Wu
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore
| | - Yixian Liu
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore
| | - Weiping Han
- Metabolism in Human Diseases Unit, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore
- Metabolism in Human Diseases Unit, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore. E-mail: or
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Röder PV, Geillinger KE, Zietek TS, Thorens B, Koepsell H, Daniel H. The role of SGLT1 and GLUT2 in intestinal glucose transport and sensing. PLoS One 2014; 9:e89977. [PMID: 24587162 PMCID: PMC3935955 DOI: 10.1371/journal.pone.0089977] [Citation(s) in RCA: 270] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022] Open
Abstract
Intestinal glucose absorption is mediated by SGLT1 whereas GLUT2 is considered to provide basolateral exit. Recently, it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion. Moreover, SGLT1 and GLUT2 are suggested to play an important role in intestinal glucose sensing and incretin secretion. In mice that lack either SGLT1 or GLUT2 we re-assessed the role of these transporters in intestinal glucose uptake after radiotracer glucose gavage and performed Western blot analysis for transporter abundance in apical membrane fractions in a comparative approach. Moreover, we examined the contribution of these transporters to glucose-induced changes in plasma GIP, GLP-1 and insulin levels. In mice lacking SGLT1, tissue retention of tracer glucose was drastically reduced throughout the entire small intestine whereas GLUT2-deficient animals exhibited higher tracer contents in tissue samples than wild type animals. Deletion of SGLT1 resulted also in reduced blood glucose elevations and abolished GIP and GLP-1 secretion in response to glucose. In mice lacking GLUT2, glucose-induced insulin but not incretin secretion was impaired. Western blot analysis revealed unchanged protein levels of SGLT1 after glucose gavage. GLUT2 detected in apical membrane fractions mainly resulted from contamination with basolateral membranes but did not change in density after glucose administration. SGLT1 is unequivocally the prime intestinal glucose transporter even at high luminal glucose concentrations. Moreover, SGLT1 mediates glucose-induced incretin secretion. Our studies do not provide evidence for GLUT2 playing any role in either apical glucose influx or incretin secretion.
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Affiliation(s)
- Pia V. Röder
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Kerstin E. Geillinger
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Tamara S. Zietek
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Bernard Thorens
- Center for Integrative Genomics, Université de Lausanne, Lausanne, Switzerland
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Würzburg, Bavaria, Germany
| | - Hannelore Daniel
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
- * E-mail:
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Geillinger KE, Kipp AP, Schink K, Röder PV, Spanier B, Daniel H. Nrf2 regulates the expression of the peptide transporter PEPT1 in the human colon carcinoma cell line Caco-2. Biochim Biophys Acta Gen Subj 2013; 1840:1747-54. [PMID: 24380877 DOI: 10.1016/j.bbagen.2013.12.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/20/2013] [Accepted: 12/20/2013] [Indexed: 12/30/2022]
Abstract
BACKGROUND PEPT1 is a rheogenic transport protein in the apical membrane of intestinal epithelial cells capable of transporting essentially all possible di- and tripeptides that are generated from the luminal protein breakdown. In addition, several anticancer, antimicrobial and antiviral drugs are taken up from the intestinal lumen via PEPT1 and therefore PEPT1 is a target for efficient drug delivery via prodrug approaches. Thus, understanding PEPT1 gene regulation is not only of importance for dietary adaptation but also for drug treatment. METHODS In silico analysis of the Pept1 promoter was performed using MatInspector. Pept1 promoter constructs were generated and cotransfected with an Nrf2 expression plasmid. Caco-2 cells were stimulated with Nrf2 inducers followed by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). Biological relevance was investigated using western blot analysis and transport activity assays. RESULTS Reporter gene assays showed transcriptional activation of the Pept1 promoter in response to Nrf2 overexpression. EMSA as well as ChIP analysis validated Nrf2 binding to the ARE located closest to the start codon (Pept1-ARE1). Induction of the Nrf2 pathway resulted in increased endogenous PEPT1 protein abundance as well as transport activity. Moreover, we demonstrate that also the induction of autophagy by MG132 resulted in elevated Nrf2 binding to Pept1-ARE1 and increased PEPT1 protein expression. CONCLUSION In summary, we identified a biologically active Nrf2 binding site within the Pept1 promoter which links Pept1 to the cellular defense program activated by Nrf2. GENERAL SIGNIFICANCE This study identifies Pept1 as an inducible target gene of the Nrf2 pathway.
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Affiliation(s)
- Kerstin E Geillinger
- ZIEL Research Center of Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising, Germany.
| | - Anna P Kipp
- Department Biochemistry of Micronutrients, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany
| | - Kristin Schink
- ZIEL Research Center of Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising, Germany
| | - Pia V Röder
- ZIEL Research Center of Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising, Germany
| | - Britta Spanier
- ZIEL Research Center of Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising, Germany
| | - Hannelore Daniel
- ZIEL Research Center of Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising, Germany
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