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Huynh FK, Peterson BS, Anderson KA, Lin Z, Coakley AJ, Llaguno FMS, Nguyen TTN, Campbell JE, Stephens SB, Newgard CB, Hirschey MD. β-Cell-specific ablation of sirtuin 4 does not affect nutrient-stimulated insulin secretion in mice. Am J Physiol Endocrinol Metab 2020; 319:E805-E813. [PMID: 32865009 PMCID: PMC7750516 DOI: 10.1152/ajpendo.00170.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Sirtuins are a family of proteins that regulate biological processes such as cellular stress and aging by removing posttranslational modifications (PTMs). We recently identified several novel PTMs that can be removed by sirtuin 4 (SIRT4), which is found in mitochondria. We showed that mice with a global loss of SIRT4 [SIRT4-knockout (KO) mice] developed an increase in glucose- and leucine-stimulated insulin secretion, and this was followed by accelerated age-induced glucose intolerance and insulin resistance. Because whole body SIRT4-KO mice had alterations to nutrient-stimulated insulin secretion, we hypothesized that SIRT4 plays a direct role in regulating pancreatic β-cell function. Thus, we tested whether β-cell-specific ablation of SIRT4 would recapitulate the elevated insulin secretion seen in mice with a global loss of SIRT4. Tamoxifen-inducible β-cell-specific SIRT4-KO mice were generated, and their glucose tolerance and glucose- and leucine-stimulated insulin secretion were measured over time. These mice exhibited normal glucose- and leucine-stimulated insulin secretion and maintained normal glucose tolerance even as they aged. Furthermore, 832/13 β-cells with a CRISPR/Cas9n-mediated loss of SIRT4 did not show any alterations in nutrient-stimulated insulin secretion. Despite the fact that whole body SIRT4-KO mice demonstrated an age-induced increase in glucose- and leucine-stimulated insulin secretion, our current data indicate that the loss of SIRT4 specifically in pancreatic β-cells, both in vivo and in vitro, does not have a significant impact on nutrient-stimulated insulin secretion. These data suggest that SIRT4 controls nutrient-stimulated insulin secretion during aging by acting on tissues external to the β-cell, which warrants further study.
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Affiliation(s)
- Frank K Huynh
- Department of Biological Sciences, San Jose State University, San Jose, California
| | - Brett S Peterson
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
| | - Kristin A Anderson
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
| | - Zhihong Lin
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
| | - Aeowynn J Coakley
- Department of Biological Sciences, San Jose State University, San Jose, California
| | - Fiara M S Llaguno
- Department of Biological Sciences, San Jose State University, San Jose, California
| | - Thi-Tina N Nguyen
- Department of Biological Sciences, San Jose State University, San Jose, California
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, North Carolina
| | - Samuel B Stephens
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Carver College of Medicine, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa
| | - Christopher B Newgard
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, North Carolina
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, North Carolina
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2
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Naiman S, Huynh FK, Gil R, Glick Y, Shahar Y, Touitou N, Nahum L, Avivi MY, Roichman A, Kanfi Y, Gertler AA, Doniger T, Ilkayeva OR, Abramovich I, Yaron O, Lerrer B, Gottlieb E, Harris RA, Gerber D, Hirschey MD, Cohen HY. SIRT6 Promotes Hepatic Beta-Oxidation via Activation of PPARα. Cell Rep 2019; 29:4127-4143.e8. [PMID: 31851938 PMCID: PMC7165364 DOI: 10.1016/j.celrep.2019.11.067] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 10/11/2019] [Accepted: 11/15/2019] [Indexed: 12/27/2022] Open
Abstract
The pro-longevity enzyme SIRT6 regulates various metabolic pathways. Gene expression analyses in SIRT6 heterozygotic mice identify significant decreases in PPARα signaling, known to regulate multiple metabolic pathways. SIRT6 binds PPARα and its response element within promoter regions and activates gene transcription. Sirt6+/- results in significantly reduced PPARα-induced β-oxidation and its metabolites and reduced alanine and lactate levels, while inducing pyruvate oxidation. Reciprocally, starved SIRT6 transgenic mice show increased pyruvate, acetylcarnitine, and glycerol levels and significantly induce β-oxidation genes in a PPARα-dependent manner. Furthermore, SIRT6 mediates PPARα inhibition of SREBP-dependent cholesterol and triglyceride synthesis. Mechanistically, SIRT6 binds PPARα coactivator NCOA2 and decreases liver NCOA2 K780 acetylation, which stimulates its activation of PPARα in a SIRT6-dependent manner. These coordinated SIRT6 activities lead to regulation of whole-body respiratory exchange ratio and liver fat content, revealing the interactions whereby SIRT6 synchronizes various metabolic pathways, and suggest a mechanism by which SIRT6 maintains healthy liver.
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Affiliation(s)
- Shoshana Naiman
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Frank K Huynh
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Reuven Gil
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yair Glick
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yael Shahar
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Noga Touitou
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Liat Nahum
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Matan Y Avivi
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Asael Roichman
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yariv Kanfi
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Asaf A Gertler
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Tirza Doniger
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Olga R Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Ifat Abramovich
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Street, Bat Galim, Haifa, Israel
| | - Orly Yaron
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Batia Lerrer
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Eyal Gottlieb
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Street, Bat Galim, Haifa, Israel
| | - Robert A Harris
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Doron Gerber
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel; Bar Ilan Institute for Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Matthew D Hirschey
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Haim Y Cohen
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel.
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3
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Tudurí E, Glavas MM, Asadi A, Baker RK, Ellis CE, Soukhatcheva G, Philit M, Huynh FK, Johnson JD, Bruce Verchere C, Kieffer TJ. AAV GCG-EGFP, a new tool to identify glucagon-secreting α-cells. Sci Rep 2019; 9:10829. [PMID: 31346189 PMCID: PMC6658537 DOI: 10.1038/s41598-019-46735-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/04/2019] [Indexed: 01/07/2023] Open
Abstract
The study of primary glucagon-secreting α-cells is hampered by their low abundance and scattered distribution in rodent pancreatic islets. We have designed a double-stranded adeno-associated virus containing a rat proglucagon promoter (700 bp) driving enhanced green fluorescent protein (AAV GCG-EGFP), to specifically identify α-cells. The administration of AAV GCG-EGFP by intraperitoneal or intraductal injection led to EGFP expression selectively in the α-cell population. AAV GCG-EGFP delivery to mice followed by islet isolation, dispersion and separation by FACS for EGFP resulted in an 86% pure population of α-cells. Furthermore, the administration of AAV GCG-EGFP at various doses to adult wild type mice did not significantly alter body weight, blood glucose, plasma insulin or glucagon levels, glucose tolerance or arginine tolerance. In vitro experiments in transgene positive α-cells demonstrated that EGFP expression did not alter the intracellular Ca2+ pattern in response to glucose or adrenaline. This approach may be useful for studying purified primary α-cells and for the in vivo delivery of other genes selectively to α-cells to further probe their function or to manipulate them for therapeutic purposes.
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Affiliation(s)
- Eva Tudurí
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.,Instituto de Investigación, Desarrollo e innovación en Biotecnología Sanitaria de Elche (IDiBE), Elche, Spain
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ali Asadi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert K Baker
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cara E Ellis
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Galina Soukhatcheva
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Marjolaine Philit
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Frank K Huynh
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Biological Sciences, San Jose State University, San Jose, CA, USA
| | - James D Johnson
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - C Bruce Verchere
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada. .,Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada.
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4
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Nicholatos JW, Robinette TM, Tata SVP, Yordy JD, Francisco AB, Platov M, Yeh TK, Ilkayeva OR, Huynh FK, Dokukin M, Volkov D, Weinstein MA, Boyko AR, Miller RA, Sokolov I, Hirschey MD, Libert S. Cellular energetics and mitochondrial uncoupling in canine aging. GeroScience 2019; 41:229-242. [PMID: 30937823 DOI: 10.1007/s11357-019-00062-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/18/2019] [Indexed: 01/02/2023] Open
Abstract
The first domesticated companion animal, the dog, is currently represented by over 190 unique breeds. Across these numerous breeds, dogs have exceptional variation in lifespan (inversely correlated with body size), presenting an opportunity to discover longevity-determining traits. We performed a genome-wide association study on 4169 canines representing 110 breeds and identified novel candidate regulators of longevity. Interestingly, known functions within the identified genes included control of coat phenotypes such as hair length, as well as mitochondrial properties, suggesting that thermoregulation and mitochondrial bioenergetics play a role in lifespan variation. Using primary dermal fibroblasts, we investigated mitochondrial properties of short-lived (large) and long-lived (small) dog breeds. We found that cells from long-lived breeds have more uncoupled mitochondria, less electron escape, greater respiration, and capacity for respiration. Moreover, our data suggest that long-lived breeds have higher rates of catabolism and β-oxidation, likely to meet elevated respiration and electron demand of their uncoupled mitochondria. Conversely, cells of short-lived (large) breeds may accumulate amino acids and fatty acid derivatives, which are likely used for biosynthesis and growth. We hypothesize that the uncoupled metabolic profile of long-lived breeds likely stems from their smaller size, reduced volume-to-surface area ratio, and therefore a greater need for thermogenesis. The uncoupled energetics of long-lived breeds lowers reactive oxygen species levels, promotes cellular stress tolerance, and may even prevent stiffening of the actin cytoskeleton. We propose that these cellular characteristics delay tissue dysfunction, disease, and death in long-lived dog breeds, contributing to canine aging diversity.
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Affiliation(s)
- Justin W Nicholatos
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA.
| | - Timothy M Robinette
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Saurabh V P Tata
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Jennifer D Yordy
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Adam B Francisco
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Michael Platov
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Tiffany K Yeh
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Olga R Ilkayeva
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC, 27701, USA
| | - Frank K Huynh
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC, 27701, USA
| | - Maxim Dokukin
- Department of Mechanical Engineering, Tufts University, Medford, MA, 02155, USA
| | - Dmytro Volkov
- Department of Mechanical Engineering, Tufts University, Medford, MA, 02155, USA
| | - Michael A Weinstein
- Department of Biomedical Engineering, Tufts University, Medford, MA, 02155, USA
| | - Adam R Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Richard A Miller
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Igor Sokolov
- Department of Mechanical Engineering, Tufts University, Medford, MA, 02155, USA.,Department of Biomedical Engineering, Tufts University, Medford, MA, 02155, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC, 27701, USA
| | - Sergiy Libert
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, 14850, USA.
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5
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Ali HR, Assiri MA, Harris PS, Michel CR, Yun Y, Marentette JO, Huynh FK, Orlicky DJ, Shearn CT, Saba LM, Reisdorph R, Reisdorph N, Hirschey MD, Fritz KS. Quantifying Competition among Mitochondrial Protein Acylation Events Induced by Ethanol Metabolism. J Proteome Res 2019; 18:1513-1531. [PMID: 30644754 DOI: 10.1021/acs.jproteome.8b00800] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction is one of many key factors in the etiology of alcoholic liver disease (ALD). Lysine acetylation is known to regulate numerous mitochondrial metabolic pathways, and recent reports demonstrate that alcohol-induced protein acylation negatively impacts these processes. To identify regulatory mechanisms attributed to alcohol-induced protein post-translational modifications, we employed a model of alcohol consumption within the context of wild type (WT), sirtuin 3 knockout (SIRT3 KO), and sirtuin 5 knockout (SIRT5 KO) mice to manipulate hepatic mitochondrial protein acylation. Mitochondrial fractions were examined by label-free quantitative HPLC-MS/MS to reveal competition between lysine acetylation and succinylation. A class of proteins defined as "differential acyl switching proteins" demonstrate select sensitivity to alcohol-induced protein acylation. A number of these proteins reveal saturated lysine-site occupancy, suggesting a significant level of differential stoichiometry in the setting of ethanol consumption. We hypothesize that ethanol downregulates numerous mitochondrial metabolic pathways through differential acyl switching proteins. Data are available via ProteomeXchange with identifier PXD012089.
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Affiliation(s)
- Hadi R Ali
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Mohammed A Assiri
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Peter S Harris
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Cole R Michel
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Youngho Yun
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - John O Marentette
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Frank K Huynh
- Department of Biological Sciences , San Jose State University , San Jose , California 95192 , United States
| | - David J Orlicky
- Department of Pathology, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Colin T Shearn
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Laura M Saba
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Richard Reisdorph
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Nichole Reisdorph
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Matthew D Hirschey
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Department of Pharmacology and Cancer Biology , Duke University Medical Center , Durham , North Carolina 27710 , United States
| | - Kristofer S Fritz
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
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Huynh FK, Anderson KA, Stuart JD, Lin Z, Hirschey MD. Sirtuin 4 controls leucine metabolism and insulin secretion by reversing effects of reactive metabolites. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.670.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Frank K. Huynh
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism CenterDurhamNC
| | - Kristin A. Anderson
- Department of Pharmacology & Cancer BiologyDuke University Medical CenterDurhamNC
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism CenterDurhamNC
| | - J. Darren Stuart
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism CenterDurhamNC
| | - Zhihong Lin
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism CenterDurhamNC
| | - Matthew D. Hirschey
- Department of Pharmacology & Cancer BiologyDuke University Medical CenterDurhamNC
- Department of MedicineDuke University Medical CenterDurhamNC
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism CenterDurhamNC
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7
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Huynh FK, Hu X, Lin Z, Johnson JD, Hirschey MD. Loss of sirtuin 4 leads to elevated glucose- and leucine-stimulated insulin levels and accelerated age-induced insulin resistance in multiple murine genetic backgrounds. J Inherit Metab Dis 2018; 41:59-72. [PMID: 28726069 PMCID: PMC5775063 DOI: 10.1007/s10545-017-0069-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 01/11/2023]
Abstract
Several inherited metabolic disorders are associated with an accumulation of reactive acyl-CoA metabolites that can non-enzymatically react with lysine residues to modify proteins. While the role of acetylation is well-studied, the pathophysiological relevance of more recently discovered acyl modifications, including those found in inherited metabolic disorders, warrants further investigation. We recently showed that sirtuin 4 (SIRT4) removes glutaryl, 3-hydroxy-3-methylglutaryl, 3-methylglutaryl, and 3-methylglutaconyl modifications from lysine residues. Thus, we used SIRT4 knockout mice, which can accumulate these novel post-translational modifications, as a model to investigate their physiological relevance. Since SIRT4 is localized to mitochondria and previous reports have shown SIRT4 influences metabolism, we thoroughly characterized glucose and lipid metabolism in male and female SIRT4KO mice across different genetic backgrounds. While only minor perturbations in overall lipid metabolism were observed, we found SIRT4KO mice consistently had elevated glucose- and leucine-stimulated insulin levels in vivo and developed accelerated age-induced insulin resistance. Importantly, elevated leucine-stimulated insulin levels in SIRT4KO mice were dependent upon genetic background since SIRT4KO mice on a C57BL/6NJ genetic background had elevated leucine-stimulated insulin levels but not SIRT4KO mice on the C57BL/6J background. Taken together, the data suggest that accumulation of acyl modifications on proteins in inherited metabolic disorders may contribute to the overall metabolic dysfunction seen in these patients.
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Affiliation(s)
- Frank K Huynh
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, 300 N. Duke Street, Durham, NC, 27701, USA
| | - Xiaoke Hu
- Department of Cellular and Physiological Sciences and Department of Surgery, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Zhihong Lin
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, 300 N. Duke Street, Durham, NC, 27701, USA
| | - James D Johnson
- Department of Cellular and Physiological Sciences and Department of Surgery, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, 300 N. Duke Street, Durham, NC, 27701, USA.
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC, 27710, USA.
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8
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Weir HJ, Yao P, Huynh FK, Escoubas CC, Goncalves RL, Burkewitz K, Laboy R, Hirschey MD, Mair WB. Dietary Restriction and AMPK Increase Lifespan via Mitochondrial Network and Peroxisome Remodeling. Cell Metab 2017; 26:884-896.e5. [PMID: 29107506 PMCID: PMC5718936 DOI: 10.1016/j.cmet.2017.09.024] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/18/2017] [Accepted: 09/27/2017] [Indexed: 01/01/2023]
Abstract
Mitochondrial network remodeling between fused and fragmented states facilitates mitophagy, interaction with other organelles, and metabolic flexibility. Aging is associated with a loss of mitochondrial network homeostasis, but cellular processes causally linking these changes to organismal senescence remain unclear. Here, we show that AMP-activated protein kinase (AMPK) and dietary restriction (DR) promote longevity in C. elegans via maintaining mitochondrial network homeostasis and functional coordination with peroxisomes to increase fatty acid oxidation (FAO). Inhibiting fusion or fission specifically blocks AMPK- and DR-mediated longevity. Strikingly, however, preserving mitochondrial network homeostasis during aging by co-inhibition of fusion and fission is sufficient itself to increase lifespan, while dynamic network remodeling is required for intermittent fasting-mediated longevity. Finally, we show that increasing lifespan via maintaining mitochondrial network homeostasis requires FAO and peroxisomal function. Together, these data demonstrate that mechanisms that promote mitochondrial homeostasis and plasticity can be targeted to promote healthy aging.
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Affiliation(s)
- Heather J Weir
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Pallas Yao
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Frank K Huynh
- Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Caroline C Escoubas
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Renata L Goncalves
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Kristopher Burkewitz
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Raymond Laboy
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - William B Mair
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
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Anderson KA, Huynh FK, Fisher-Wellman K, Stuart JD, Peterson BS, Douros JD, Wagner GR, Thompson JW, Madsen AS, Green MF, Sivley RM, Ilkayeva OR, Stevens RD, Backos DS, Capra JA, Olsen CA, Campbell JE, Muoio DM, Grimsrud PA, Hirschey MD. SIRT4 Is a Lysine Deacylase that Controls Leucine Metabolism and Insulin Secretion. Cell Metab 2017; 25:838-855.e15. [PMID: 28380376 PMCID: PMC5444661 DOI: 10.1016/j.cmet.2017.03.003] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 09/26/2016] [Accepted: 03/06/2017] [Indexed: 01/17/2023]
Abstract
Sirtuins are NAD+-dependent protein deacylases that regulate several aspects of metabolism and aging. In contrast to the other mammalian sirtuins, the primary enzymatic activity of mitochondrial sirtuin 4 (SIRT4) and its overall role in metabolic control have remained enigmatic. Using a combination of phylogenetics, structural biology, and enzymology, we show that SIRT4 removes three acyl moieties from lysine residues: methylglutaryl (MG)-, hydroxymethylglutaryl (HMG)-, and 3-methylglutaconyl (MGc)-lysine. The metabolites leading to these post-translational modifications are intermediates in leucine oxidation, and we show a primary role for SIRT4 in controlling this pathway in mice. Furthermore, we find that dysregulated leucine metabolism in SIRT4KO mice leads to elevated basal and stimulated insulin secretion, which progressively develops into glucose intolerance and insulin resistance. These findings identify a robust enzymatic activity for SIRT4, uncover a mechanism controlling branched-chain amino acid flux, and position SIRT4 as a crucial player maintaining insulin secretion and glucose homeostasis during aging.
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Affiliation(s)
- Kristin A Anderson
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Frank K Huynh
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Kelsey Fisher-Wellman
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - J Darren Stuart
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Brett S Peterson
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Jonathan D Douros
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Gregory R Wagner
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - J Will Thompson
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Proteomics and Metabolomics Shared Resource, Duke University Medical Center, Durham, NC 27710, USA
| | - Andreas S Madsen
- Center for Biopharmaceuticals and Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Michelle F Green
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - R Michael Sivley
- Department of Biological Sciences, Department of Biomedical Informatics, Vanderbilt Genetics Institute, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Olga R Ilkayeva
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Robert D Stevens
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Donald S Backos
- Computational Chemistry and Biology Core Facility, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - John A Capra
- Department of Biological Sciences, Department of Biomedical Informatics, Vanderbilt Genetics Institute, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Christian A Olsen
- Center for Biopharmaceuticals and Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Deborah M Muoio
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Paul A Grimsrud
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA.
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Madsen AS, Andersen C, Daoud M, Anderson KA, Laursen JS, Chakladar S, Huynh FK, Colaço AR, Backos DS, Fristrup P, Hirschey MD, Olsen CA. Investigating the Sensitivity of NAD+-dependent Sirtuin Deacylation Activities to NADH. J Biol Chem 2016; 291:7128-41. [PMID: 26861872 DOI: 10.1074/jbc.m115.668699] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Indexed: 11/06/2022] Open
Abstract
Protein lysine posttranslational modification by an increasing number of different acyl groups is becoming appreciated as a regulatory mechanism in cellular biology. Sirtuins are class III histone deacylases that use NAD(+)as a co-substrate during amide bond hydrolysis. Several studies have described the sirtuins as sensors of the NAD(+)/NADH ratio, but it has not been formally tested for all the mammalian sirtuinsin vitro To address this problem, we first synthesized a wide variety of peptide-based probes, which were used to identify the range of hydrolytic activities of human sirtuins. These probes included aliphatic ϵ-N-acyllysine modifications with hydrocarbon lengths ranging from formyl (C1) to palmitoyl (C16) as well as negatively charged dicarboxyl-derived modifications. In addition to the well established activities of the sirtuins, "long chain" acyllysine modifications were also shown to be prone to hydrolytic cleavage by SIRT1-3 and SIRT6, supporting recent findings. We then tested the ability of NADH, ADP-ribose, and nicotinamide to inhibit these NAD(+)-dependent deacylase activities of the sirtuins. In the commonly used 7-amino-4-methylcoumarin-coupled fluorescence-based assay, the fluorophore has significant spectral overlap with NADH and therefore cannot be used to measure inhibition by NADH. Therefore, we turned to an HPLC-MS-based assay to directly monitor the conversion of acylated peptides to their deacylated forms. All tested sirtuin deacylase activities showed sensitivity to NADH in this assay. However, the inhibitory concentrations of NADH in these assays are far greater than the predicted concentrations of NADH in cells; therefore, our data indicate that NADH is unlikely to inhibit sirtuinsin vivo These data suggest a re-evaluation of the sirtuins as direct sensors of the NAD(+)/NADH ratio.
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Affiliation(s)
- Andreas S Madsen
- From the Center for Biopharmaceuticals, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark, the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark,
| | - Christian Andersen
- the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Mohammad Daoud
- the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Kristin A Anderson
- the Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Jonas S Laursen
- From the Center for Biopharmaceuticals, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Saswati Chakladar
- From the Center for Biopharmaceuticals, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Frank K Huynh
- the Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Ana R Colaço
- the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Donald S Backos
- the Computational Chemistry and Biology Core Facility, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Peter Fristrup
- the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Matthew D Hirschey
- the Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Christian A Olsen
- From the Center for Biopharmaceuticals, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark, the Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark,
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11
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Affiliation(s)
- Frank K Huynh
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC
| | - Deborah M Muoio
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC Sarah W. Stedman Nutrition and Metabolism Center and Departments of Medicine and Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC Sarah W. Stedman Nutrition and Metabolism Center and Departments of Medicine and Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC
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Abstract
While much oncological research has focused on metabolic shifts in glucose and amino acid oxidation, recent evidence suggests that fatty acid oxidation (FAO) may also play an important role in the metabolic reprogramming of cancer cells. Here, we present a simple method for measuring FAO rates using radiolabeled palmitate, common laboratory reagents, and standard supplies. This protocol is broadly applicable for measuring FAO rates in cultured cancer cells as well as in both malignant and nontransformed animal tissues.
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Affiliation(s)
- Frank K Huynh
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Michelle F Green
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Timothy R Koves
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, USA; Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, USA; Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
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13
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Burkewitz K, Morantte I, Weir HJM, Yeo R, Zhang Y, Huynh FK, Ilkayeva OR, Hirschey MD, Grant AR, Mair WB. Neuronal CRTC-1 governs systemic mitochondrial metabolism and lifespan via a catecholamine signal. Cell 2015; 160:842-855. [PMID: 25723162 DOI: 10.1016/j.cell.2015.02.004] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/21/2014] [Accepted: 01/28/2015] [Indexed: 12/21/2022]
Abstract
Low energy states delay aging in multiple species, yet mechanisms coordinating energetics and longevity across tissues remain poorly defined. The conserved energy sensor AMP-activated protein kinase (AMPK) and its corresponding phosphatase calcineurin modulate longevity via the CREB regulated transcriptional coactivator (CRTC)-1 in C. elegans. We show that CRTC-1 specifically uncouples AMPK/calcineurin-mediated effects on lifespan from pleiotropic side effects by reprogramming mitochondrial and metabolic function. This pro-longevity metabolic state is regulated cell nonautonomously by CRTC-1 in the nervous system. Neuronal CRTC-1/CREB regulates peripheral metabolism antagonistically with the functional PPARα ortholog, NHR-49, drives mitochondrial fragmentation in distal tissues, and suppresses the effects of AMPK on systemic mitochondrial metabolism and longevity via a cell-nonautonomous catecholamine signal. These results demonstrate that while both local and distal mechanisms combine to modulate aging, distal regulation overrides local contribution. Targeting central perception of energetic state is therefore a potential strategy to promote healthy aging.
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Affiliation(s)
- Kristopher Burkewitz
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Ianessa Morantte
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Heather J M Weir
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Robin Yeo
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Yue Zhang
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Frank K Huynh
- Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Olga R Ilkayeva
- Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Ana R Grant
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, 100 Washtenah Avenue, Ann Arbor, MI 48109, USA
| | - William B Mair
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
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Abstract
The mammalian sirtuins have emerged as critical regulators of cellular stress resistance, energy metabolism, and tumorigenesis. In some contexts, they delay the onset of age-related diseases and promote a healthy lifespan. The seven mammalian sirtuins, SIRT1-7, share a highly conserved NAD+-binding catalytic core domain although they exhibit distinct expression patterns, catalytic activities, and biological functions. This SnapShot provides an overview of these properties, with an emphasis on their relevance to aging.
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Affiliation(s)
- Kristin A Anderson
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Michelle F Green
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Frank K Huynh
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Gregory R Wagner
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Matthew D Hirschey
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine and Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
The fat‐derived hormone, leptin, is well known to regulate body weight. However, there is now substantial evidence that leptin also plays a primary role in the regulation of glucose homeostasis, independent of actions on food intake, energy expenditure or body weight. As such, leptin might have clinical utility in treating hyperglycemia, particularly in conditions of leptin deficiency, such as lipodystrophy and diabetes mellitus. The mechanisms through which leptin modulates glucose metabolism have not been fully elucidated. Leptin receptors are widely expressed in peripheral tissues, including the endocrine pancreas, liver, skeletal muscle and adipose, and both direct and indirect leptin action on these tissues contributes to the control of glucose homeostasis. Here we review the role of leptin in glucose homeostasis, along with our present understanding of the mechanisms involved. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00203.x, 2012)
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Affiliation(s)
- Heather C Denroche
- Department of Cellular and Physiological Sciences, The Life Sciences Institute
| | - Frank K Huynh
- Department of Cellular and Physiological Sciences, The Life Sciences Institute
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, The Life Sciences Institute ; Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Sirtuins are a class of NAD+-dependent deacetylases, such as deacetylases, that have a wide array of biological functions. Recent studies have suggested that reduced sirtuin action is correlated with Type 2 diabetes. Both overnutrition and aging, which are two major risk factors for diabetes, lead to decreased sirtuin function and result in abnormal glucose and lipid metabolism. Therefore, restoring normal levels of sirtuin action in Type 2 diabetes may be a promising method of treating diabetes. This article reviews the biological functions of three of the seven mammalian sirtuins - SIRT1, SIRT3 and SIRT6 - that have demonstrated prominent metabolic roles and early potential for drug targeting. Clinical trials investigating the use of sirtuin activators for treating diabetes are already underway and show promise as alternatives to current diabetes therapies. Thus, further research into sirtuin activators is warranted and may lead to a new class of safe, effective diabetes treatments.
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Affiliation(s)
- Frank K Huynh
- Sarah W Stedman Nutrition & Metabolism Center, Duke University Medical Center, Durham, NC 27704, USA
| | - Kathleen A Hershberger
- Sarah W Stedman Nutrition & Metabolism Center, Duke University Medical Center, Durham, NC 27704, USA ; Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Matthew D Hirschey
- Sarah W Stedman Nutrition & Metabolism Center, Duke University Medical Center, Durham, NC 27704, USA ; Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA ; Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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Huynh FK, Neumann UH, Wang Y, Rodrigues B, Kieffer TJ, Covey SD. A role for hepatic leptin signaling in lipid metabolism via altered very low density lipoprotein composition and liver lipase activity in mice. Hepatology 2013; 57:543-54. [PMID: 22941940 DOI: 10.1002/hep.26043] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 08/13/2012] [Indexed: 01/21/2023]
Abstract
UNLABELLED Obesity is highly associated with dyslipidemia and cardiovascular disease. However, the mechanism behind this association is not completely understood. The hormone leptin may be a molecular link between obesity and dysregulation of lipid metabolism. Leptin can affect lipid metabolism independent of its well-known effects on food intake and energy expenditure, but exactly how this occurs is ill-defined. We hypothesized that since leptin receptors are found on the liver and the liver plays an integral role in regulating lipid metabolism, leptin may affect lipid metabolism by acting directly on the liver. To test this hypothesis, we generated mice with a hepatocyte-specific loss of leptin signaling. We previously showed that these mice have increased insulin sensitivity and elevated levels of liver triglycerides compared with controls. Here, we show that mice lacking hepatic leptin signaling have decreased levels of plasma apolipoprotein B yet increased levels of very low density lipoprotein (VLDL) triglycerides, suggesting alterations in triglyceride incorporation into VLDL or abnormal lipoprotein remodeling in the plasma. Indeed, lipoprotein profiles revealed larger apolipoprotein B-containing lipoprotein particles in mice with ablated liver leptin signaling. Loss of leptin signaling in the liver was also associated with a substantial increase in lipoprotein lipase activity in the liver, which may have contributed to increased lipid droplets in the liver. CONCLUSION Lack of hepatic leptin signaling results in increased lipid accumulation in the liver and larger, more triglyceride-rich VLDL particles. Collectively, these data reveal an interesting role for hepatic leptin signaling in modulating triglyceride metabolism.
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Affiliation(s)
- Frank K Huynh
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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18
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Tuduri E, Glavas MM, Baker RK, Huynh FK, Riedel MJ, Kieffer TJ. Adeno-associated Virus (AAV) for In Vivo a– and b– Cell Gene Delivery. Can J Diabetes 2012. [DOI: 10.1016/j.jcjd.2012.07.420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Levi J, Huynh FK, Denroche HC, Neumann UH, Glavas MM, Covey SD, Kieffer TJ. Hepatic leptin signalling and subdiaphragmatic vagal efferents are not required for leptin-induced increases of plasma IGF binding protein-2 (IGFBP-2) in ob/ob mice. Diabetologia 2012; 55:752-62. [PMID: 22202803 DOI: 10.1007/s00125-011-2426-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 11/28/2011] [Indexed: 01/19/2023]
Abstract
AIMS/HYPOTHESIS The fat-derived hormone leptin plays a crucial role in the maintenance of normal body weight and energy expenditure as well as in glucose homeostasis. Recently, it was reported that the liver-derived protein, insulin-like growth factor binding protein-2 (IGFBP-2), is responsible for at least some of the glucose-normalising effects of leptin. However, the exact mechanism by which leptin upregulates IGFBP-2 production is unknown. Since it is believed that circulating IGFBP-2 is predominantly derived from the liver and leptin has been shown to have both direct and indirect actions on the liver, we hypothesised that leptin signalling in hepatocytes or via brain-liver vagal efferents may mediate leptin control of IGFBP-2 production. METHODS To address our hypothesis, we assessed leptin action on glucose homeostasis and plasma IGFBP-2 levels in both leptin-deficient ob/ob mice with a liver-specific loss of leptin signalling and ob/ob mice with a subdiaphragmatic vagotomy. We also examined whether restoring hepatic leptin signalling in leptin receptor-deficient db/db mice could increase plasma IGFBP-2 levels. RESULTS Continuous leptin administration increased plasma IGFBP-2 levels in a dose-dependent manner, in association with reduced plasma glucose and insulin levels. Interestingly, leptin was still able to increase plasma IGFBP-2 levels and improve glucose homeostasis in both ob/ob mouse models to the same extent as their littermate controls. Further, restoration of hepatic leptin signalling in db/db mice did not increase either hepatic or plasma IGFBP-2 levels. CONCLUSIONS/INTERPRETATION Taken together, these data indicate that hepatic leptin signalling and subdiaphragmatic vagal inputs are not required for leptin upregulation of plasma IGFBP-2 nor blood glucose lowering in ob/ob mice.
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Affiliation(s)
- J Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Levi J, Gray SL, Speck M, Huynh FK, Babich SL, Gibson WT, Kieffer TJ. Acute disruption of leptin signaling in vivo leads to increased insulin levels and insulin resistance. Endocrinology 2011; 152:3385-95. [PMID: 21750049 DOI: 10.1210/en.2011-0185] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Leptin, an adipocyte-derived hormone, plays an essential role in the maintenance of normal body weight and energy expenditure, as well as glucose homeostasis. Indeed, leptin-deficient ob/ob mice are obese with profound hyperinsulinemia, insulin resistance, and often hyperglycemia. Interestingly, low doses of exogenous leptin can reverse the hyperinsulinemia and hyperglycemia in these animals without altering body weight. The hyperinsulinemia in ob/ob mice may result directly from the absence of leptin signaling in pancreatic β-cells and, in turn, contribute to both obesity and insulin resistance. Here, we acutely attenuated endogenous leptin signaling in normal mice with a polyethylene glycol (PEG)ylated mouse leptin antagonist (PEG-MLA) to determine the contribution of leptin signaling in the regulation of glucose homeostasis. PEG-MLA was either injected or continuously administered via osmotic minipumps for several days, and various metabolic parameters were assessed. PEG-MLA-treated mice had increased fasting and glucose-stimulated plasma insulin levels, decreased whole-body insulin sensitivity, elevated hepatic glucose production, and impaired insulin-mediated suppression of hepatic glucose production. Moreover, PEG-MLA treatment resulted in increased food intake and increased respiratory quotient without significantly altering energy expenditure or body composition as assessed by the lean:lipid ratio. Our findings indicate that alterations in insulin sensitivity occur before changes in the lean:lipid ratio and energy expenditure during the acute disruption of endogenous leptin signaling.
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Affiliation(s)
- Jasna Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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21
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Denroche HC, Levi J, Wideman RD, Sequeira RM, Huynh FK, Covey SD, Kieffer TJ. Leptin therapy reverses hyperglycemia in mice with streptozotocin-induced diabetes, independent of hepatic leptin signaling. Diabetes 2011; 60:1414-23. [PMID: 21464443 PMCID: PMC3292314 DOI: 10.2337/db10-0958] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Leptin therapy has been found to reverse hyperglycemia and prevent mortality in several rodent models of type 1 diabetes. Yet the mechanism of leptin-mediated reversal of hyperglycemia has not been fully defined. The liver is a key organ regulating glucose metabolism and is also a target of leptin action. Thus we hypothesized that exogenous leptin administered to mice with streptozotocin (STZ)-induced diabetes reverses hyperglycemia through direct action on hepatocytes. RESEARCH DESIGN AND METHODS After the induction of diabetes in mice with a high dose of STZ, recombinant mouse leptin was delivered at a supraphysiological dose for 14 days by an osmotic pump implant. We characterized the effect of leptin administration in C57Bl/6J mice with STZ-induced diabetes and then examined whether leptin therapy could reverse STZ-induced hyperglycemia in mice in which hepatic leptin signaling was specifically disrupted. RESULTS Hyperleptinemia reversed hyperglycemia and hyperketonemia in diabetic C57Bl/6J mice and dramatically improved glucose tolerance. These effects were associated with reduced plasma glucagon and growth hormone levels and dramatically enhanced insulin sensitivity, without changes in glucose uptake by skeletal muscle. Leptin therapy also ameliorated STZ-induced hyperglycemia and hyperketonemia in mice with disrupted hepatic leptin signaling to a similar extent as observed in wild-type littermates with STZ-induced diabetes. CONCLUSIONS These observations reveal that hyperleptinemia reverses the symptoms of STZ-induced diabetes in mice and that this action does not require direct leptin signaling in the liver.
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Affiliation(s)
- Heather C. Denroche
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jasna Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rhonda D. Wideman
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Roveena M. Sequeira
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Frank K. Huynh
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scott D. Covey
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Timothy J. Kieffer
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding author: Timothy J. Kieffer,
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Huynh FK, Levi J, Denroche HC, Gray SL, Voshol PJ, Neumann UH, Speck M, Chua SC, Covey SD, Kieffer TJ. Disruption of hepatic leptin signaling protects mice from age- and diet-related glucose intolerance. Diabetes 2010; 59:3032-40. [PMID: 20876720 PMCID: PMC2992763 DOI: 10.2337/db10-0074] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The liver plays a critical role in integrating and controlling glucose metabolism. Thus, it is important that the liver receive and react to signals from other tissues regarding the nutrient status of the body. Leptin, which is produced and secreted from adipose tissue, is a hormone that relays information regarding the status of adipose depots to other parts of the body. Leptin has a profound influence on glucose metabolism, so we sought to determine if leptin may exert this effect in part through the liver. RESEARCH DESIGN AND METHODS To explore this possibility, we created mice that have disrupted hepatic leptin signaling using a Cre-lox approach and then investigated aspects of glucose metabolism in these animals. RESULTS The loss of hepatic leptin signaling did not alter body weight, body composition, or blood glucose levels in the mild fasting or random-fed state. However, mice with ablated hepatic leptin signaling had increased lipid accumulation in the liver. Further, as male mice aged or were fed a high-fat diet, the loss of hepatic leptin signaling protected the mice from glucose intolerance. Moreover, the mice displayed increased liver insulin sensitivity and a trend toward enhanced glucose-stimulated plasma insulin levels. Consistent with increased insulin sensitivity, mice with ablated hepatic leptin signaling had increased insulin-stimulated phosphorylation of Akt in the liver. CONCLUSIONS These data reveal that unlike a complete deficiency of leptin action, which results in impaired glucose homeostasis, disruption of leptin action in the liver alone increases hepatic insulin sensitivity and protects against age- and diet-related glucose intolerance. Thus, leptin appears to act as a negative regulator of insulin action in the liver.
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Affiliation(s)
- Frank K. Huynh
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jasna Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Heather C. Denroche
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarah L. Gray
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter J. Voshol
- Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Ursula H. Neumann
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Madeleine Speck
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Streamson C. Chua
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, New York, New York
| | - Scott D. Covey
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding authors: Scott D. Covey, , and Timothy J. Kieffer,
| | - Timothy J. Kieffer
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding authors: Scott D. Covey, , and Timothy J. Kieffer,
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