1
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Marhl M. What do stimulated beta cells have in common with cancer cells? Biosystems 2024; 242:105257. [PMID: 38876357 DOI: 10.1016/j.biosystems.2024.105257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/11/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
This study investigates the metabolic parallels between stimulated pancreatic beta cells and cancer cells, focusing on glucose and glutamine metabolism. Addressing the significant public health challenges of Type 2 Diabetes (T2D) and cancer, we aim to deepen our understanding of the mechanisms driving insulin secretion and cellular proliferation. Our analysis of anaplerotic cycles and the role of NADPH in biosynthesis elucidates their vital functions in both processes. Additionally, we point out that both cell types share an antioxidative response mediated by the Nrf2 signaling pathway, glutathione synthesis, and UCP2 upregulation. Notably, UCP2 facilitates the transfer of C4 metabolites, enhancing reductive TCA cycle metabolism. Furthermore, we observe that hypoxic responses are transient in beta cells post-stimulation but persistent in cancer cells. By synthesizing these insights, the research may suggest novel therapeutic targets for T2D, highlighting the shared metabolic strategies of stimulated beta cells and cancer cells. This comparative analysis not only illuminates the metabolic complexity of these conditions but also emphasizes the crucial role of metabolic pathways in cell function and survival, offering fresh perspectives for tackling T2D and cancer challenges.
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Affiliation(s)
- Marko Marhl
- Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000, Maribor, Slovenia; Faculty of Education, University of Maribor, Koroška cesta 160, 2000, Maribor, Slovenia; Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000, Maribor, Slovenia.
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2
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Grubelnik V, Zmazek J, Gosak M, Marhl M. The role of anaplerotic metabolism of glucose and glutamine in insulin secretion: A model approach. Biophys Chem 2024; 311:107270. [PMID: 38833963 DOI: 10.1016/j.bpc.2024.107270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
We propose a detailed computational beta cell model that emphasizes the role of anaplerotic metabolism under glucose and glucose-glutamine stimulation. This model goes beyond the traditional focus on mitochondrial oxidative phosphorylation and ATP-sensitive K+ channels, highlighting the predominant generation of ATP from phosphoenolpyruvate in the vicinity of KATP channels. It also underlines the modulatory role of H2O2 as a signaling molecule in the first phase of glucose-stimulated insulin secretion. In the second phase, the model emphasizes the critical role of anaplerotic pathways, activated by glucose stimulation via pyruvate carboxylase and by glutamine via glutamate dehydrogenase. It particularly focuses on the production of NADPH and glutamate as key enhancers of insulin secretion. The predictions of the model are consistent with empirical data, highlighting the complex interplay of metabolic pathways and emphasizing the primary role of glucose and the facilitating role of glutamine in insulin secretion. By delineating these crucial metabolic pathways, the model provides valuable insights into potential therapeutic targets for diabetes.
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Affiliation(s)
- Vladimir Grubelnik
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška cesta 46, 2000 Maribor, Slovenia
| | - Jan Zmazek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Alma Mater Europaea ECM, Slovenska ulica 17, 2000 Maribor, Slovenia
| | - Marko Marhl
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Faculty of Education, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia.
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3
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Chong ACN, Vandana JJ, Jeng G, Li G, Meng Z, Duan X, Zhang T, Qiu Y, Duran-Struuck R, Coker K, Wang W, Li Y, Min Z, Zuo X, de Silva N, Chen Z, Naji A, Hao M, Liu C, Chen S. Checkpoint kinase 2 controls insulin secretion and glucose homeostasis. Nat Chem Biol 2024; 20:566-576. [PMID: 37945898 PMCID: PMC11062908 DOI: 10.1038/s41589-023-01466-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 10/03/2023] [Indexed: 11/12/2023]
Abstract
After the discovery of insulin, a century ago, extensive work has been done to unravel the molecular network regulating insulin secretion. Here we performed a chemical screen and identified AZD7762, a compound that potentiates glucose-stimulated insulin secretion (GSIS) of a human β cell line, healthy and type 2 diabetic (T2D) human islets and primary cynomolgus macaque islets. In vivo studies in diabetic mouse models and cynomolgus macaques demonstrated that AZD7762 enhances GSIS and improves glucose tolerance. Furthermore, genetic manipulation confirmed that ablation of CHEK2 in human β cells results in increased insulin secretion. Consistently, high-fat-diet-fed Chk2-/- mice show elevated insulin secretion and improved glucose clearance. Finally, untargeted metabolic profiling demonstrated the key role of the CHEK2-PP2A-PLK1-G6PD-PPP pathway in insulin secretion. This study successfully identifies a previously unknown insulin secretion regulating pathway that is conserved across rodents, cynomolgus macaques and human β cells in both healthy and T2D conditions.
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Affiliation(s)
- Angie Chi Nok Chong
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - J Jeya Vandana
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York City, NY, USA
| | - Ginnie Jeng
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ge Li
- Department of Medicine, Weill Cornell Medicine, New York City, NY, USA
- Department of Biological Sciences, Bronx Community College, City University of New York, Bronx, NY, USA
| | - Zihe Meng
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - Xiaohua Duan
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - Tuo Zhang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York City, NY, USA
| | - Yunping Qiu
- Department of Medicine, Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Raimon Duran-Struuck
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Kimberly Coker
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Wei Wang
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Yanjing Li
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Zaw Min
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Xi Zuo
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Neranjan de Silva
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
| | - Zhengming Chen
- Department of Population Health Sciences, Weill Cornell Medicine, New York City, NY, USA
| | - Ali Naji
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Mingming Hao
- Department of Biochemistry, Weill Cornell Medicine, New York City, NY, USA
| | - Chengyang Liu
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
| | - Shuibing Chen
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA.
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA.
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4
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Essaouiba A, Jellali R, Gilard F, Gakière B, Okitsu T, Legallais C, Sakai Y, Leclerc E. Investigation of the Exometabolomic Profiles of Rat Islets of Langerhans Cultured in Microfluidic Biochip. Metabolites 2022; 12:metabo12121270. [PMID: 36557308 PMCID: PMC9786643 DOI: 10.3390/metabo12121270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Diabetes mellitus (DM) is a complex disease with high prevalence of comorbidity and mortality. DM is predicted to reach more than 700 million people by 2045. In recent years, several advanced in vitro models and analytical tools were developed to investigate the pancreatic tissue response to pathological situations and identify therapeutic solutions. Of all the in vitro promising models, cell culture in microfluidic biochip allows the reproduction of in-vivo-like micro-environments. Here, we cultured rat islets of Langerhans using dynamic cultures in microfluidic biochips. The dynamic cultures were compared to static islets cultures in Petri. The islets' exometabolomic signatures, with and without GLP1 and isradipine treatments, were characterized by GC-MS. Compared to Petri, biochip culture contributes to maintaining high secretions of insulin, C-peptide and glucagon. The exometabolomic profiling revealed 22 and 18 metabolites differentially expressed between Petri and biochip on Day 3 and 5. These metabolites illustrated the increase in lipid metabolism, the perturbation of the pentose phosphate pathway and the TCA cycle in biochip. After drug stimulations, the exometabolome of biochip culture appeared more perturbed than the Petri exometabolome. The GLP1 contributed to the increase in the levels of glycolysis, pentose phosphate and glutathione pathways intermediates, whereas isradipine led to reduced levels of lipids and carbohydrates.
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Affiliation(s)
- Amal Essaouiba
- Biomechanics and Bioengineering, CNRS, Université de Technologie de Compiègne, Centre de Recherche Royallieu CS 60319, 60203 Compiègne, France
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Rachid Jellali
- Biomechanics and Bioengineering, CNRS, Université de Technologie de Compiègne, Centre de Recherche Royallieu CS 60319, 60203 Compiègne, France
- Correspondence: (R.J.); (E.L.)
| | - Françoise Gilard
- Plateforme Métabolisme-Métabolome, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Université Paris Cité, Bâtiment 360, Avenue des Sciences, 91190 Gif sur Yvette, France
| | - Bertrand Gakière
- Plateforme Métabolisme-Métabolome, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Université Paris Cité, Bâtiment 360, Avenue des Sciences, 91190 Gif sur Yvette, France
| | - Teru Okitsu
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Cécile Legallais
- Biomechanics and Bioengineering, CNRS, Université de Technologie de Compiègne, Centre de Recherche Royallieu CS 60319, 60203 Compiègne, France
| | - Yasuyuki Sakai
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- Department of Chemical Engineering, Faculty of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Eric Leclerc
- Biomechanics and Bioengineering, CNRS, Université de Technologie de Compiègne, Centre de Recherche Royallieu CS 60319, 60203 Compiègne, France
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- Correspondence: (R.J.); (E.L.)
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5
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Abstract
This review focuses on the human pancreatic islet-including its structure, cell composition, development, function, and dysfunction. After providing a historical timeline of key discoveries about human islets over the past century, we describe new research approaches and technologies that are being used to study human islets and how these are providing insight into human islet physiology and pathophysiology. We also describe changes or adaptations in human islets in response to physiologic challenges such as pregnancy, aging, and insulin resistance and discuss islet changes in human diabetes of many forms. We outline current and future interventions being developed to protect, restore, or replace human islets. The review also highlights unresolved questions about human islets and proposes areas where additional research on human islets is needed.
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Affiliation(s)
- John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Diane C Saunders
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Marcela Brissova
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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6
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Abstract
The reactions of the tricarboxylic acid (TCA) cycle allow the controlled combustion of fat and carbohydrate. In principle, TCA cycle intermediates are regenerated on every turn and can facilitate the oxidation of an infinite number of nutrient molecules. However, TCA cycle intermediates can be lost to cataplerotic pathways that provide precursors for biosynthesis, and they must be replaced by anaplerotic pathways that regenerate these intermediates. Together, anaplerosis and cataplerosis help regulate rates of biosynthesis by dictating precursor supply, and they play underappreciated roles in catabolism and cellular energy status. They facilitate recycling pathways and nitrogen trafficking necessary for catabolism, and they influence redox state and oxidative capacity by altering TCA cycle intermediate concentrations. These functions vary widely by tissue and play emerging roles in disease. This article reviews the roles of anaplerosis and cataplerosis in various tissues and discusses how they alter carbon transitions, and highlights their contribution to mechanisms of disease. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Melissa Inigo
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
| | - Stanisław Deja
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Shawn C Burgess
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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7
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Abstract
Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of evidence affirms support for novel regulation, by G proteins, of specific intracellular signaling events, including actin cytoskeletal remodeling, transport of insulin-containing granules to the plasma membrane for fusion, and secretion of insulin into the circulation. This article highlights the following aspects of GPCR-G protein biology of the islet. First, it overviews our current understanding of the identity of a wide variety of G protein regulators and their modulatory roles in GPCR-G protein-effector coupling, which is requisite for optimal β-cell function under physiological conditions. Second, it describes evidence in support of novel, noncanonical, GPCR-independent mechanisms of activation of G proteins in the islet. Third, it highlights the evidence indicating that abnormalities in G protein function lead to islet β-cell dysregulation and demise under the duress of metabolic stress and diabetes. Fourth, it summarizes observations of potential beneficial effects of GPCR agonists in preventing/halting metabolic defects in the islet β-cell under various pathological conditions (e.g., metabolic stress and inflammation). Lastly, it identifies knowledge gaps and potential avenues for future research in this evolving field of translational islet biology. Published 2020. Compr Physiol 10:453-490, 2020.
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Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Center for Translational Research in Diabetes, Biomedical Research Service, John D. Dingell VA Medical Center, Wayne State University, Detroit, Michigan, USA
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8
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Metabolomics Analysis of Nutrient Metabolism in β-Cells. J Mol Biol 2020; 432:1429-1445. [DOI: 10.1016/j.jmb.2019.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 01/05/2023]
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9
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Prentki M, Corkey BE, Madiraju SRM. Lipid-associated metabolic signalling networks in pancreatic beta cell function. Diabetologia 2020; 63:10-20. [PMID: 31423551 DOI: 10.1007/s00125-019-04976-w] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/29/2019] [Indexed: 01/01/2023]
Abstract
Significant advances have been made in deciphering the mechanisms underlying fuel-stimulated insulin secretion by pancreatic beta cells. The contribution of the triggering/ATP-sensitive potassium (KATP)-dependent Ca2+ signalling and KATP-independent amplification pathways, that include anaplerosis and lipid signalling of glucose-stimulated insulin secretion (GSIS), are well established. A proposed model included a key role for a metabolic partitioning 'switch', the acetyl-CoA carboxylase (ACC)/malonyl-CoA/carnitine palmitoyltransferase-1 (CPT-1) axis, in beta cell glucose and fatty acid signalling for insulin secretion. This model has gained overwhelming support from a number of studies in recent years and is now refined through its link to the glycerolipid/NEFA cycle that provides lipid signals through its lipolysis arm. Furthermore, acetyl-CoA carboxylase may also control beta cell growth. Here we review the evidence supporting a role for the ACC/malonyl-CoA/CPT-1 axis in the control of GSIS and its particular importance under conditions of elevated fatty acids (e.g. fasting, excess nutrients, hyperlipidaemia and diabetes). We also document how it is linked to a more global lipid signalling system that includes the glycerolipid/NEFA cycle.
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Affiliation(s)
- Marc Prentki
- Department of Nutrition, University of Montreal, Montréal, QC, Canada.
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada.
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada.
| | - Barbara E Corkey
- Evans Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, MA, USA
| | - S R Murthy Madiraju
- Department of Nutrition, University of Montreal, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada
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10
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Peterson BS, Campbell JE, Ilkayeva O, Grimsrud PA, Hirschey MD, Newgard CB. Remodeling of the Acetylproteome by SIRT3 Manipulation Fails to Affect Insulin Secretion or β Cell Metabolism in the Absence of Overnutrition. Cell Rep 2019; 24:209-223.e6. [PMID: 29972782 PMCID: PMC6093627 DOI: 10.1016/j.celrep.2018.05.088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/10/2018] [Accepted: 05/25/2018] [Indexed: 12/19/2022] Open
Abstract
SIRT3 is a nicotinamide adenine dinucleotide (NAD+)- dependent mitochondrial protein deacetylase purported to influence metabolism through post-translational modification of metabolic enzymes. Fuel-stimulated insulin secretion, which involves mitochondrial metabolism, could be susceptible to SIRT3-mediated effects. We used CRISPR/Cas9 technology to manipulate SIRT3 expression in β cells, resulting in widespread SIRT3-dependent changes in acetylation of key metabolic enzymes but no appreciable changes in glucose- or pyruvate-stimulated insulin secretion or metabolomic profile during glucose stimulation. Moreover, these broad changes in the SIRT3-targeted acetylproteome did not affect responses to nutritional or ER stress. We also studied mice with global SIRT3 knockout fed either standard chow (STD) or high-fat and high-sucrose (HFHS) diets. Only when chronically fed HFHS diet do SIRT3 KO animals exhibit a modest reduction in insulin secretion. We conclude that broad changes in mitochondrial protein acetylation in response to manipulation of SIRT3 are not sufficient to cause changes in islet function or metabolism. Peterson et al. report that ablation of SIRT3 in 832/13 β cells dramatically alters the mitochondrial acetylproteome but does not affect insulin secretion, metabolomic profile, or β cell survival. Moreover, SIRT3 knockout causes a modest reduction in insulin secretion in mice fed a high-fat and high-sucrose but not a standard chow diet.
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Affiliation(s)
- Brett S Peterson
- 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
| | - 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
| | - Olga Ilkayeva
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27701, 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
| | - Christopher B Newgard
- 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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11
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Scarl RT, Corbin KL, Vann NW, Smith HM, Satin LS, Sherman A, Nunemaker CS. Intact pancreatic islets and dispersed beta-cells both generate intracellular calcium oscillations but differ in their responsiveness to glucose. Cell Calcium 2019; 83:102081. [PMID: 31563790 DOI: 10.1016/j.ceca.2019.102081] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/12/2019] [Accepted: 09/14/2019] [Indexed: 01/19/2023]
Abstract
Pancreatic islets produce pulses of insulin and other hormones that maintain normal glucose homeostasis. These micro-organs possess exquisite glucose-sensing capabilities, allowing for precise changes in pulsatile insulin secretion in response to small changes in glucose. When communication among these cells is disrupted, precision glucose sensing falters. We measured intracellular calcium patterns in 6-mM-steps between 0 and 16 mM glucose, and also more finely in 2-mM-steps from 8 to 12 mM glucose, to compare glucose sensing systematically among intact islets and dispersed islet cells derived from the same mouse pancreas in vitro. The calcium activity of intact islets was uniformly low (quiescent) below 4 mM glucose and active above 8 mM glucose, whereas dispersed beta-cells displayed a broader activation range (2-to-10 mM). Intact islets exhibited calcium oscillations with 2-to-5-min periods, yet beta-cells exhibited longer 7-10 min periods. In every case, intact islets showed changes in activity with each 6-mM-glucose step, whereas dispersed islet cells displayed a continuum of calcium responses ranging from islet-like patterns to stable oscillations unaffected by changes in glucose concentration. These differences were also observed for 2-mM-glucose steps. Despite the diversity of dispersed beta-cell responses to glucose, the sum of all activity produced a glucose dose-response curve that was surprisingly similar to the curve for intact islets, arguing against the importance of "hub cells" for function. Beta-cells thus retain many of the features of islets, but some are more islet-like than others. Determining the molecular underpinnings of these variations could be valuable for future studies of stem-cell-derived beta-cell therapies.
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Affiliation(s)
- Rachel T Scarl
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
| | - Kathryn L Corbin
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States; Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
| | - Nicholas W Vann
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States
| | - Hallie M Smith
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
| | - Leslie S Satin
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, MI, United States; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Arthur Sherman
- Laboratory of Biological Modeling, NIDDK, NIH, Bethesda, MD, United States
| | - Craig S Nunemaker
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States; Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States.
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12
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Westermeier F, Holyoak T, Asenjo JL, Gatica R, Nualart F, Burbulis I, Bertinat R. Gluconeogenic Enzymes in β-Cells: Pharmacological Targets for Improving Insulin Secretion. Trends Endocrinol Metab 2019; 30:520-531. [PMID: 31213347 DOI: 10.1016/j.tem.2019.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
Abstract
Pancreatic β-cells express the gluconeogenic enzymes glucose 6-phosphatase (G6Pase), fructose 1,6-bisphosphatase (FBP), and phosphoenolpyruvate (PEP) carboxykinase (PCK), which modulate glucose-stimulated insulin secretion (GSIS) through their ability to reverse otherwise irreversible glycolytic steps. Here, we review current knowledge about the expression and regulation of these enzymes in the context of manipulating them to improve insulin secretion in diabetics. Because the regulation of gluconeogenic enzymes in β-cells is so poorly understood, we propose novel research avenues to study these enzymes as modulators of insulin secretion and β-cell dysfunction, with especial attention to FBP, which constitutes an attractive target with an inhibitor under clinical evaluation at present.
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Affiliation(s)
- Francisco Westermeier
- FH JOANNEUM Gesellschaft mbH University of Applied Sciences, Institute of Biomedical Science, Eggenberger Allee 13, 8020 Graz, Austria
| | - Todd Holyoak
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Joel L Asenjo
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Independencia 631, 5110566 Valdivia, Chile
| | - Rodrigo Gatica
- Escuela de Veterinaria, Facultad de Ciencias, Universidad Mayor, La Pirámide 5750, 8580745 Santiago, Chile
| | - Francisco Nualart
- Centro de Microscopía Avanzada, CMA BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160 C, 4030000 Concepción, Chile
| | - Ian Burbulis
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Jordan Hall Room 6022, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA; Escuela de Medicina, Universidad San Sebastián, Sede Patagonia, Lago Panguipulli 1390, 5501842 Puerto Montt, Chile
| | - Romina Bertinat
- Centro de Microscopía Avanzada, CMA BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160 C, 4030000 Concepción, Chile.
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The Metabolomic Signatures of Weight Change. Metabolites 2019; 9:metabo9040067. [PMID: 30987392 PMCID: PMC6523676 DOI: 10.3390/metabo9040067] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 04/03/2019] [Indexed: 12/17/2022] Open
Abstract
Obesity represents a major health concern, not just in the West but increasingly in low and middle income countries. In order to develop successful strategies for losing weight, it is essential to understand the molecular pathogenesis of weight change. A number of pathways, implicating oxidative stress but also the fundamental regulatory of insulin, have been implicated in weight gain and in the regulation of energy expenditure. In addition, a considerable body of work has highlighted the role of metabolites generated by the gut microbiome, in particular short chain fatty acids, in both processes. The current review provides a brief understanding of the mechanisms underlying the associations of weight change with changes in lipid and amino acid metabolism, energy metabolism, dietary composition and insulin dynamics, as well as the influence of the gut microbiome. The changes in metabolomic profiles and the models outlined can be used as an accurate predictor for obesity and obesity related disorders.
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Kelly SC, Patel NN, Eccardt AM, Fisher JS. Glucose-dependent trans-plasma membrane electron transport and p70 S6k phosphorylation in skeletal muscle cells. Redox Biol 2018; 27:101075. [PMID: 30578122 PMCID: PMC6859557 DOI: 10.1016/j.redox.2018.101075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 11/05/2022] Open
Abstract
The reduction of extracellular oxidants by intracellular electrons is known as trans-plasma membrane electron transport (tPMET). The goal of this study was to characterize a role of tPMET in the sensing of glucose as a physiological signal. tPMET from C2C12 myotubes was monitored using a cell-impermeable extracellular electron acceptor, water-soluble tetrazolium salt-1 (WST-1). Superoxide dismutase in the incubation medium or exposure to an NADPH oxidase (NOX) isoform 1/4 inhibitor suppressed WST-1 reduction by 70%, suggesting a role of NOXs in tPMET. There was a positive correlation between medium glucose concentration and WST-1 reduction, suggesting that tPMET is a glucose-sensing process. WST-1 reduction was also decreased by an inhibitor of the pentose phosphate pathway, dehydroepiandrosterone. In contrast, glycolytic inhibitors, 3PO and sodium fluoride, did not affect WST-1 reduction. Thus, it appears that glucose uptake and processing in the pentose phosphate pathway drives NOX-dependent tPMET. Western blot analysis demonstrated that p70S6k phosphorylation is glucose-dependent, while the phosphorylation of AKT and MAPK did not differ in the presence or absence of glucose. Further, phosphorylation of p70S6k was dependent upon NOX enzymes. Finally, glucose was required for full stimulation of p70S6k by insulin, again in a fashion prevented by NOX inhibition. Taken together, the data suggest that muscle cells have a novel glucose-sensing mechanism dependent on NADPH production and NOX activity, culminating in increased p70S6k phosphorylation.
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Affiliation(s)
- Shannon C Kelly
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Neej N Patel
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Amanda M Eccardt
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Jonathan S Fisher
- Department of Biology, Saint Louis University, St. Louis, MO, United States.
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