1
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Jin E, Briggs JK, Benninger RKP, Merrins MJ. Glucokinase activity controls subpopulations of β-cells that alternately lead islet Ca 2+ oscillations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.21.608680. [PMID: 39229244 PMCID: PMC11370332 DOI: 10.1101/2024.08.21.608680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Oscillations in insulin secretion, driven by islet Ca2+ waves, are crucial for glycemic control. Prior studies, performed with single-plane imaging, suggest that subpopulations of electrically coupled β-cells have privileged roles in leading and coordinating the propagation of Ca2+ waves. Here, we used 3D light-sheet imaging to analyze the location and Ca2+ activity of single β-cells within the entire islet at >2 Hz. In contrast with single-plane studies, 3D network analysis indicates that the most highly synchronized β-cells are located at the islet center, and remain regionally but not cellularly stable between oscillations. This subpopulation, which includes 'hub cells', is insensitive to changes in fuel metabolism induced by glucokinase and pyruvate kinase activation. β-cells that initiate the Ca2+ wave ('leaders') are located at the islet periphery, and strikingly, change their identity over time via rotations in the wave axis. Glucokinase activation, which increased oscillation period, reinforced leader cells and stabilized the wave axis. Pyruvate kinase activation, despite increasing oscillation frequency, had no effect on leader cells, indicating the wave origin is patterned by fuel input. These findings emphasize the stochastic nature of the β-cell subpopulations that control Ca2+ oscillations and identify a role for glucokinase in spatially patterning 'leader' β-cells.
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Affiliation(s)
- Erli Jin
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI, United States
| | - Jennifer K Briggs
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, United States; Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, United States
| | - Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, United States; Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, United States
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI, United States
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2
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Knuth ER, Foster HR, Jin E, Ekstrand MH, Knudsen JG, Merrins MJ. Leucine Suppresses α-Cell cAMP and Glucagon Secretion via a Combination of Cell-Intrinsic and Islet Paracrine Signaling. Diabetes 2024; 73:1426-1439. [PMID: 38870025 PMCID: PMC11333377 DOI: 10.2337/db23-1013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 06/10/2024] [Indexed: 06/15/2024]
Abstract
Glucagon is critical for the maintenance of blood glucose, however nutrient regulation of pancreatic α-cells remains poorly understood. Here, we identified a role of leucine, a well-known β-cell fuel, in the α-cell-intrinsic regulation of glucagon release. In islet perifusion assays, physiologic concentrations of leucine strongly inhibited alanine- and arginine-stimulated glucagon secretion from human and mouse islets under hypoglycemic conditions. Mechanistically, leucine dose-dependently reduced α-cell cAMP, independently of Ca2+, ATP/ADP, or fatty acid oxidation. Leucine also reduced α-cell cAMP in islets treated with somatostatin receptor 2 antagonists or diazoxide, compounds that limit paracrine signaling from β/δ-cells. Studies in dispersed mouse islets confirmed an α-cell-intrinsic effect. The inhibitory effect of leucine on cAMP was mimicked by glucose, α-ketoisocaproate, succinate, and the glutamate dehydrogenase activator BCH and blocked by cyanide, indicating a mechanism dependent on mitochondrial metabolism. Glucose dose-dependently reduced the impact of leucine on α-cell cAMP, indicating an overlap in function; however, leucine was still effective at suppressing glucagon secretion in the presence of elevated glucose, amino acids, and the incretin GIP. Taken together, these findings show that leucine plays an intrinsic role in limiting the α-cell secretory tone across the physiologic range of glucose levels, complementing the inhibitory paracrine actions of β/δ-cells. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Emily R. Knuth
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Hannah R. Foster
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Erli Jin
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Maia H. Ekstrand
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jakob G. Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Matthew J. Merrins
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
- William S. Middleton Memorial Veterans Hospital, Madison, WI
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3
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Fagundes RR, Zaldumbide A, Taylor CT. Role of hypoxia-inducible factor 1 in type 1 diabetes. Trends Pharmacol Sci 2024; 45:798-810. [PMID: 39127527 DOI: 10.1016/j.tips.2024.07.001] [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: 06/05/2024] [Revised: 07/08/2024] [Accepted: 07/11/2024] [Indexed: 08/12/2024]
Abstract
Type 1 diabetes (T1D) is a common autoimmune disease in which dysregulated glucose metabolism is a key feature. T1D is both poorly understood and in need of improved therapeutics. Hypoxia is frequently encountered in multiple tissues in T1D patients including the pancreas and sites of diabetic complications. Hypoxia-inducible factor (HIF)-1, a ubiquitous master regulator of the adaptive response to hypoxia, promotes glucose metabolism through transcriptional and non-transcriptional mechanisms and alters disease progression in multiple preclinical T1D models. However, how HIF-1 activation in β-cells of the pancreas and immune cells (two key cell types in T1D) ultimately affects disease progression remains controversial. We discuss recent advances in our understanding of the role of hypoxia/HIF-1-induced glycolysis in T1D and explore the possible use of drugs targeting this pathway as potential new therapeutics.
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Affiliation(s)
- Raphael R Fagundes
- Department of Cell and Chemical Biology, Leiden University Medical Center, Albinusdreef 2, Leiden, The Netherlands
| | - Arnaud Zaldumbide
- Department of Cell and Chemical Biology, Leiden University Medical Center, Albinusdreef 2, Leiden, The Netherlands
| | - Cormac T Taylor
- School of Medicine and Conway Institute of Biomolecular and Biomedical Research and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
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4
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Wang H, Vant JW, Zhang A, Sanchez RG, Wu Y, Micou ML, Luczak V, Whiddon Z, Carlson NM, Yu SB, Jabbo M, Yoon S, Abushawish AA, Ghassemian M, Masubuchi T, Gan Q, Watanabe S, Griffis ER, Hammarlund M, Singharoy A, Pekkurnaz G. Organization of a functional glycolytic metabolon on mitochondria for metabolic efficiency. Nat Metab 2024; 6:1712-1735. [PMID: 39261628 DOI: 10.1038/s42255-024-01121-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 08/02/2024] [Indexed: 09/13/2024]
Abstract
Glucose, the primary cellular energy source, is metabolized through glycolysis initiated by the rate-limiting enzyme hexokinase (HK). In energy-demanding tissues like the brain, HK1 is the dominant isoform, primarily localized on mitochondria, and is crucial for efficient glycolysis-oxidative phosphorylation coupling and optimal energy generation. This study unveils a unique mechanism regulating HK1 activity, glycolysis and the dynamics of mitochondrial coupling, mediated by the metabolic sensor enzyme O-GlcNAc transferase (OGT). OGT catalyses reversible O-GlcNAcylation, a post-translational modification influenced by glucose flux. Elevated OGT activity induces dynamic O-GlcNAcylation of the regulatory domain of HK1, subsequently promoting the assembly of the glycolytic metabolon on the outer mitochondrial membrane. This modification enhances the mitochondrial association with HK1, orchestrating glycolytic and mitochondrial ATP production. Mutation in HK1's O-GlcNAcylation site reduces ATP generation in multiple cell types, specifically affecting metabolic efficiency in neurons. This study reveals a previously unappreciated pathway that links neuronal metabolism and mitochondrial function through OGT and the formation of the glycolytic metabolon, providing potential strategies for tackling metabolic and neurological disorders.
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Affiliation(s)
- Haoming Wang
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - John W Vant
- Biodesign Institute, The School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Andrew Zhang
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Richard G Sanchez
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Youjun Wu
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Mary L Micou
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Thomas Jefferson University, Philadelphia, PA, USA
| | - Vincent Luczak
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Neurocrine Biosciences, San Diego, CA, USA
| | - Zachary Whiddon
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Natasha M Carlson
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Seungyoon B Yu
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Denali Therapeutics Inc., South San Francisco, CA, USA
| | - Mirna Jabbo
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Seokjun Yoon
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- University of Southern California, Los Angeles, CA, USA
| | - Ahmed A Abushawish
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Majid Ghassemian
- Biomolecular and Proteomics Mass Spectrometry Facility, University of California San Diego, La Jolla, CA, USA
| | - Takeya Masubuchi
- Cell and Developmental Biology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Quan Gan
- Department of Cell Biology, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Shigeki Watanabe
- Department of Cell Biology, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Eric R Griffis
- Nikon Imaging Center, University of California San Diego, La Jolla, CA, USA
- Altos Labs, San Diego, CA, USA
| | - Marc Hammarlund
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Abhishek Singharoy
- Biodesign Institute, The School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Gulcin Pekkurnaz
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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5
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Ježek P, Dlasková A, Engstová H, Špačková J, Tauber J, Průchová P, Kloppel E, Mozheitova O, Jabůrek M. Mitochondrial Physiology of Cellular Redox Regulations. Physiol Res 2024; 73:S217-S242. [PMID: 38647168 PMCID: PMC11412358 DOI: 10.33549/physiolres.935269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
Mitochondria (mt) represent the vital hub of the molecular physiology of the cell, being decision-makers in cell life/death and information signaling, including major redox regulations and redox signaling. Now we review recent advances in understanding mitochondrial redox homeostasis, including superoxide sources and H2O2 consumers, i.e., antioxidant mechanisms, as well as exemplar situations of physiological redox signaling, including the intramitochondrial one and mt-to-cytosol redox signals, which may be classified as acute and long-term signals. This review exemplifies the acute redox signals in hypoxic cell adaptation and upon insulin secretion in pancreatic beta-cells. We also show how metabolic changes under these circumstances are linked to mitochondrial cristae narrowing at higher intensity of ATP synthesis. Also, we will discuss major redox buffers, namely the peroxiredoxin system, which may also promote redox signaling. We will point out that pathological thresholds exist, specific for each cell type, above which the superoxide sources exceed regular antioxidant capacity and the concomitant harmful processes of oxidative stress subsequently initiate etiology of numerous diseases. The redox signaling may be impaired when sunk in such excessive pro-oxidative state.
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Affiliation(s)
- P Ježek
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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6
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Satin LS, Corradi J, Sherman AS. Do We Need a New Hypothesis for KATP Closure in β-Cells? Distinguishing the Baby From the Bathwater. Diabetes 2024; 73:844-848. [PMID: 38640066 PMCID: PMC11109778 DOI: 10.2337/db24-0131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 03/15/2024] [Indexed: 04/21/2024]
Affiliation(s)
- Leslie Sherwin Satin
- Department of Pharmacology and Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, Brehm Diabetes Center and Caswell Diabetes Institute, University of Michigan Medical School, Ann Arbor, MI
| | - Jeremías Corradi
- Department of Pharmacology and Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, Brehm Diabetes Center and Caswell Diabetes Institute, University of Michigan Medical School, Ann Arbor, MI
| | - Arthur Stewart Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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7
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Merrins MJ, Kibbey RG. Glucose Regulation of β-Cell KATP Channels: It Is Time for a New Model! Diabetes 2024; 73:856-863. [PMID: 38768366 PMCID: PMC11109790 DOI: 10.2337/dbi23-0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/04/2024] [Indexed: 05/22/2024]
Abstract
An agreed-upon consensus model of glucose-stimulated insulin secretion from healthy β-cells is essential for understanding diabetes pathophysiology. Since the discovery of the KATP channel in 1984, an oxidative phosphorylation (OxPhos)-driven rise in ATP has been assumed to close KATP channels to initiate insulin secretion. This model lacks any evidence, genetic or otherwise, that mitochondria possess the bioenergetics to raise the ATP/ADP ratio to the triggering threshold, and conflicts with genetic evidence demonstrating that OxPhos is dispensable for insulin secretion. It also conflates the stoichiometric yield of OxPhos with thermodynamics, and overestimates OxPhos by failing to account for established features of β-cell metabolism, such as leak, anaplerosis, cataplerosis, and NADPH production that subtract from the efficiency of mitochondrial ATP production. We have proposed an alternative model, based on the spatial and bioenergetic specializations of β-cell metabolism, in which glycolysis initiates insulin secretion. The evidence for this model includes that 1) glycolysis has high control strength over insulin secretion; 2) glycolysis is active at the correct time to explain KATP channel closure; 3) plasma membrane-associated glycolytic enzymes control KATP channels; 4) pyruvate kinase has favorable bioenergetics, relative to OxPhos, for raising ATP/ADP; and 5) OxPhos stalls before membrane depolarization and increases after. Although several key experiments remain to evaluate this model, the 1984 model is based purely on circumstantial evidence and must be rescued by causal, mechanistic experiments if it is to endure.
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Affiliation(s)
- Matthew J. Merrins
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin—Madison
- William S. Middleton Memorial Veterans Hospital, Madison, WI
| | - Richard G. Kibbey
- Departments of Internal Medicine (Endocrinology) and Cellular & Molecular Physiology, Yale University, New Haven, CT
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8
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Rutter GA, Sweet IR. Glucose Regulation of β-Cell KATP Channels: Is a New Model Needed? Diabetes 2024; 73:849-855. [PMID: 38768365 PMCID: PMC11109788 DOI: 10.2337/dbi23-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/18/2023] [Indexed: 05/22/2024]
Abstract
The canonical model of glucose-induced increase in insulin secretion involves the metabolism of glucose via glycolysis and the citrate cycle, resulting in increased ATP synthesis by the respiratory chain and the closure of ATP-sensitive K+ (KATP) channels. The resulting plasma membrane depolarization, followed by Ca2+ influx through L-type Ca2+ channels, then induces insulin granule fusion. Merrins and colleagues have recently proposed an alternative model whereby KATP channels are controlled by pyruvate kinase, using glycolytic and mitochondrial phosphoenolpyruvate (PEP) to generate microdomains of high ATP/ADP immediately adjacent to KATP channels. This model presents several challenges. First, how mitochondrially generated PEP, but not ATP produced abundantly by the mitochondrial F1F0-ATP synthase, can gain access to the proposed microdomains is unclear. Second, ATP/ADP fluctuations imaged immediately beneath the plasma membrane closely resemble those in the bulk cytosol. Third, ADP privation of the respiratory chain at high glucose, suggested to drive alternating, phased-locked generation by mitochondria of ATP or PEP, has yet to be directly demonstrated. Finally, the approaches used to explore these questions may be complicated by off-target effects. We suggest instead that Ca2+ changes, well known to affect both ATP generation and consumption, likely drive cytosolic ATP/ADP oscillations that in turn regulate KATP channels and membrane potential. Thus, it remains to be demonstrated that a new model is required to replace the existing, mitochondrial bioenergetics-based model.
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Affiliation(s)
- Guy A. Rutter
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, Québéc, Canada
- Department of Metabolism, Digestion, and Reproduction, Imperial College London, Hammersmith Hospital Campus, London, U.K
- Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - Ian R. Sweet
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA
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9
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Cuozzo F, Viloria K, Shilleh AH, Nasteska D, Frazer-Morris C, Tong J, Jiao Z, Boufersaoui A, Marzullo B, Rosoff DB, Smith HR, Bonner C, Kerr-Conte J, Pattou F, Nano R, Piemonti L, Johnson PRV, Spiers R, Roberts J, Lavery GG, Clark A, Ceresa CDL, Ray DW, Hodson L, Davies AP, Rutter GA, Oshima M, Scharfmann R, Merrins MJ, Akerman I, Tennant DA, Ludwig C, Hodson DJ. LDHB contributes to the regulation of lactate levels and basal insulin secretion in human pancreatic β cells. Cell Rep 2024; 43:114047. [PMID: 38607916 PMCID: PMC11164428 DOI: 10.1016/j.celrep.2024.114047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 02/19/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Using 13C6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1H-13C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning β cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and β cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human β cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in β cells to maintain appropriate insulin release.
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Affiliation(s)
- Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Katrina Viloria
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Ali H Shilleh
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Charlotte Frazer-Morris
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jason Tong
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Zicong Jiao
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Geneplus-Beijing, Changping District, Beijing 102206, China
| | - Adam Boufersaoui
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Bryan Marzullo
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Daniel B Rosoff
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; Oxford Kavli Centre for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Hannah R Smith
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Caroline Bonner
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Julie Kerr-Conte
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Francois Pattou
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Rita Nano
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Lorenzo Piemonti
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Rebecca Spiers
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jennie Roberts
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Centre for Systems Health and Integrated Metabolic Research (SHiMR), Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - David W Ray
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; Oxford Kavli Centre for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Amy P Davies
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; CHUM Research Centre and Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Masaya Oshima
- Université Paris Cité, Institut Cochin, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Raphaël Scharfmann
- Université Paris Cité, Institut Cochin, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Ildem Akerman
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - Christian Ludwig
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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10
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Xia Q, Lan J, Pan Y, Wang Y, Song T, Yang Y, Tian X, Chen L, Gu Z, Ding YY. Effects of Dityrosine on Lactic Acid Metabolism in Mice Gastrocnemius Muscle During Endurance Exercise via the Oxidative Stress-Induced Mitochondria Damage. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:5269-5282. [PMID: 38439706 DOI: 10.1021/acs.jafc.3c09649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
Dityrosine (Dityr) has been detected in commercial food as a product of protein oxidation and has been shown to pose a threat to human health. This study aims to investigate whether Dityr causes a decrease in lactic acid metabolism in the gastrocnemius muscle during endurance exercise. C57BL/6 mice were administered Dityr or saline by gavage for 13 weeks and underwent an endurance exercise test on a treadmill. Dityr caused a severe reduction in motion displacement and endurance time, along with a significant increase in lactic acid accumulation in the blood and gastrocnemius muscle in mice after exercise. Dityr induced significant mitochondrial defects in the gastrocnemius muscle of mice. Additionally, Dityr induced serious oxidative stress in the gastrocnemius muscle, accompanied by inflammation, which might be one of the causes of mitochondrial dysfunction. Moreover, significant apoptosis in the gastrocnemius muscle increased after exposure to Dityr. This study confirmed that Dityr induced oxidative stress in the gastrocnemius muscle, which further caused significant mitochondrial damage in the gastrocnemius muscle cell, resulting in decreased capacity of lactic acid metabolism and finally affected performance in endurance exercise. This may be one of the possible mechanisms by which highly oxidized foods cause a decreased muscle energy metabolism.
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Affiliation(s)
- Qiudong Xia
- Department of Physical Education, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Jinchi Lan
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Yuxiang Pan
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Yuxin Wang
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Tianyuan Song
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Ying Yang
- Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xu Tian
- Beijing Competitor Sports Nutrition Research Institute, Beijing 100027, China
| | - Longjun Chen
- Huzhou Shengtao Biotechnology LLC, Huzhou 313000, China
| | - Zhenyu Gu
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Yin-Yi Ding
- Food Safety Key Laboratory of Zhejiang Province, National Experimental Teaching Demonstration Center for Food Engineering and Quality and Safety, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
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11
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Longden TA, Lederer WJ. Electro-metabolic signaling. J Gen Physiol 2024; 156:e202313451. [PMID: 38197953 PMCID: PMC10783436 DOI: 10.1085/jgp.202313451] [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: 07/26/2023] [Revised: 10/27/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Precise matching of energy substrate delivery to local metabolic needs is essential for the health and function of all tissues. Here, we outline a mechanistic framework for understanding this critical process, which we refer to as electro-metabolic signaling (EMS). All tissues exhibit changes in metabolism over varying spatiotemporal scales and have widely varying energetic needs and reserves. We propose that across tissues, common signatures of elevated metabolism or increases in energy substrate usage that exceed key local thresholds rapidly engage mechanisms that generate hyperpolarizing electrical signals in capillaries that then relax contractile elements throughout the vasculature to quickly adjust blood flow to meet changing needs. The attendant increase in energy substrate delivery serves to meet local metabolic requirements and thus avoids a mismatch in supply and demand and prevents metabolic stress. We discuss in detail key examples of EMS that our laboratories have discovered in the brain and the heart, and we outline potential further EMS mechanisms operating in tissues such as skeletal muscle, pancreas, and kidney. We suggest that the energy imbalance evoked by EMS uncoupling may be central to cellular dysfunction from which the hallmarks of aging and metabolic diseases emerge and may lead to generalized organ failure states-such as diverse flavors of heart failure and dementia. Understanding and manipulating EMS may be key to preventing or reversing these dysfunctions.
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Affiliation(s)
- Thomas A. Longden
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W. Jonathan Lederer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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12
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Sivadas A, McDonald EF, Shuster SO, Davis CM, Plate L. Site-specific crosslinking reveals Phosphofructokinase-L inhibition drives self-assembly and attenuation of protein interactions. Adv Biol Regul 2023; 90:100987. [PMID: 37806136 PMCID: PMC11108229 DOI: 10.1016/j.jbior.2023.100987] [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: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/10/2023]
Abstract
Phosphofructokinase is the central enzyme in glycolysis and constitutes a highly regulated step. The liver isoform (PFKL) compartmentalizes during activation and inhibition in vitro and in vivo, respectively. Compartmentalized PFKL is hypothesized to modulate metabolic flux consistent with its central role as the rate limiting step in glycolysis. PFKL tetramers self-assemble at two interfaces in the monomer (interface 1 and 2), yet how these interfaces contribute to PFKL compartmentalization and drive protein interactions remains unclear. Here, we used site-specific incorporation of noncanonical photocrosslinking amino acids to identify PFKL interactors at interface 1, 2, and the active site. Tandem mass tag-based quantitative interactomics reveals interface 2 as a hotspot for PFKL interactions, particularly with cytoskeletal, glycolytic, and carbohydrate derivative metabolic proteins. Furthermore, PFKL compartmentalization into puncta was observed in human cells using citrate inhibition. Puncta formation attenuated crosslinked protein-protein interactions with the cytoskeleton at interface 2. This result suggests that PFKL compartmentalization sequesters interface 2, but not interface 1, and may modulate associated protein assemblies with the cytoskeleton.
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Affiliation(s)
- Athira Sivadas
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Eli Fritz McDonald
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | | | - Caitlin M Davis
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
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13
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Corradi J, Thompson B, Fletcher PA, Bertram R, Sherman AS, Satin LS. K ATP channel activity and slow oscillations in pancreatic beta cells are regulated by mitochondrial ATP production. J Physiol 2023; 601:5655-5667. [PMID: 37983196 PMCID: PMC10842208 DOI: 10.1113/jp284982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 10/16/2023] [Indexed: 11/22/2023] Open
Abstract
Pancreatic beta cells secrete insulin in response to plasma glucose. The ATP-sensitive potassium channel (KATP ) links glucose metabolism to islet electrical activity in these cells by responding to increased cytosolic [ATP]/[ADP]. It was recently proposed that pyruvate kinase (PK) in close proximity to beta cell KATP locally produces the ATP that inhibits KATP activity. This proposal was largely based on the observation that applying phosphoenolpyruvate (PEP) and ADP to the cytoplasmic side of excised inside-out patches inhibited KATP . To test the relative contributions of local vs. mitochondrial ATP production, we recorded KATP activity using mouse beta cells and INS-1 832/13 cells. In contrast to prior reports, we could not replicate inhibition of KATP activity by PEP + ADP. However, when the pH of the PEP solutions was not corrected for the addition of PEP, strong channel inhibition was observed as a result of the well-known action of protons to inhibit KATP . In cell-attached recordings, perifusing either a PK activator or an inhibitor had little or no effect on KATP channel closure by glucose, further suggesting that PK is not an important regulator of KATP . In contrast, addition of mitochondrial inhibitors robustly increased KATP activity. Finally, by measuring the [ATP]/[ADP] responses to imposed calcium oscillations in mouse beta cells, we found that oxidative phosphorylation could raise [ATP]/[ADP] even when ADP was at its nadir during the burst silent phase, in agreement with our mathematical model. These results indicate that ATP produced by mitochondrial oxidative phosphorylation is the primary controller of KATP in pancreatic beta cells. KEY POINTS: Phosphoenolpyruvate (PEP) plus adenosine diphosphate does not inhibit KATP activity in excised patches. PEP solutions only inhibit KATP activity if the pH is unbalanced. Modulating pyruvate kinase has minimal effects on KATP activity. Mitochondrial inhibition, in contrast, robustly potentiates KATP activity in cell-attached patches. Although the ADP level falls during the silent phase of calcium oscillations, mitochondria can still produce enough ATP via oxidative phosphorylation to close KATP . Mitochondrial oxidative phosphorylation is therefore the main source of the ATP that inhibits the KATP activity of pancreatic beta cells.
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Affiliation(s)
- Jeremías Corradi
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Benjamin Thompson
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Patrick A. Fletcher
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Arthur S. Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Leslie S. Satin
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
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14
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Vived C, Lee-Papastavros A, Aparecida da Silva Pereira J, Yi P, MacDonald TL. β Cell Stress and Endocrine Function During T1D: What Is Next to Discover? Endocrinology 2023; 165:bqad162. [PMID: 37947352 DOI: 10.1210/endocr/bqad162] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/27/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
Canonically, type 1 diabetes (T1D) is a disease characterized by autoreactive T cells as perpetrators of endocrine dysfunction and β cell death in the spiral toward loss of β cell mass, hyperglycemia, and insulin dependence. β Cells have mostly been considered as bystanders in a flurry of autoimmune processes. More recently, our framework for understanding and investigating T1D has evolved. It appears increasingly likely that intracellular β cell stress is an important component of T1D etiology/pathology that perpetuates autoimmunity during the progression to T1D. Here we discuss the emerging and complex role of β cell stress in initiating, provoking, and catalyzing T1D. We outline the bridges between hyperglycemia, endoplasmic reticulum stress, oxidative stress, and autoimmunity from the viewpoint of intrinsic β cell (dys)function, and we extend this discussion to the potential role for a therapeutic β cell stress-metabolism axis in T1D. Lastly, we mention research angles that may be pursued to improve β cell endocrine function during T1D. Biology gleaned from studying T1D will certainly overlap to innovate therapeutic strategies for T2D, and also enhance the pursuit of creating optimized stem cell-derived β cells as endocrine therapy.
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Affiliation(s)
- Celia Vived
- Section for Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | | | - Jéssica Aparecida da Silva Pereira
- Section for Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Peng Yi
- Section for Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Diabetes Program, Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Tara L MacDonald
- Section for Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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15
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Sivadas A, McDonald EF, Shuster SO, Davis CM, Plate L. Site-Specific Crosslinking Reveals Phosphofructokinase-L Inhibition Drives Self-Assembly and Attenuation of Protein Interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558525. [PMID: 37781627 PMCID: PMC10541129 DOI: 10.1101/2023.09.19.558525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Phosphofructokinase is the central enzyme in glycolysis and constitutes a highly regulated step. The liver isoform (PFKL) compartmentalizes during activation and inhibition in vitro and in vivo respectively. Compartmentalized PFKL is hypothesized to modulate metabolic flux consistent with its central role as the rate limiting step in glycolysis. PFKL tetramers self-assemble at two interfaces in the monomer (interface 1 and 2), yet how these interfaces contribute to PFKL compartmentalization and drive protein interactions remains unclear. Here, we used site-specific incorporation of noncanonical photocrosslinking amino acids to identify PFKL interactors at interface 1, 2, and the active site. Tandem mass tag-based quantitative interactomics reveals interface 2 as a hotspot for PFKL interactions, particularly with cytoskeletal, glycolytic, and carbohydrate derivative metabolic proteins. Furthermore, PFKL compartmentalization into puncta was observed in human cells using citrate inhibition. Puncta formation attenuated crosslinked protein-protein interactions with the cytoskeleton at interface 2. This result suggests that PFKL compartmentalization sequesters interface 2, but not interface 1, and may modulate associated protein assemblies with the cytoskeleton.
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Affiliation(s)
- Athira Sivadas
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Eli Fritz McDonald
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | | | | | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
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16
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Lang AL, Nissanka N, Louzada RA, Tamayo A, Pereira E, Moraes CT, Caicedo A. A Defect in Mitochondrial Complex III but Not in Complexes I or IV Causes Early β-Cell Dysfunction and Hyperglycemia in Mice. Diabetes 2023; 72:1262-1276. [PMID: 37343239 PMCID: PMC10451017 DOI: 10.2337/db22-0728] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/04/2023] [Indexed: 06/23/2023]
Abstract
Mitochondrial metabolism and oxidative respiration are crucial for pancreatic β-cell function and stimulus secretion coupling. Oxidative phosphorylation (OxPhos) produces ATP and other metabolites that potentiate insulin secretion. However, the contribution of individual OxPhos complexes to β-cell function is unknown. We generated β-cell-specific, inducible OxPhos complex knock-out (KO) mouse models to investigate the effects of disrupting complex I, complex III, or complex IV on β-cell function. Although all KO models had similar mitochondrial respiratory defects, complex III caused early hyperglycemia, glucose intolerance, and loss of glucose-stimulated insulin secretion in vivo. However, ex vivo insulin secretion did not change. Complex I and IV KO models showed diabetic phenotypes much later. Mitochondrial Ca2+ responses to glucose stimulation 3 weeks after gene deletion ranged from not affected to severely disrupted, depending on the complex targeted, supporting the unique roles of each complex in β-cell signaling. Mitochondrial antioxidant enzyme immunostaining increased in islets from complex III KO, but not from complex I or IV KO mice, indicating that severe diabetic phenotype in the complex III-deficient mice is causing alterations in cellular redox status. The present study highlights that defects in individual OxPhos complexes lead to different pathogenic outcomes. ARTICLE HIGHLIGHTS Mitochondrial metabolism is critical for β-cell insulin secretion, and mitochondrial dysfunction is involved in type 2 diabetes pathogenesis. We determined whether individual oxidative phosphorylation complexes contribute uniquely to β-cell function. Compared with loss of complex I and IV, loss of complex III resulted in severe in vivo hyperglycemia and altered β-cell redox status. Loss of complex III altered cytosolic and mitochondrial Ca2+ signaling and increased expression of glycolytic enzymes. Individual complexes contribute differently to β-cell function. This underscores the role of mitochondrial oxidative phosphorylation complex defects in diabetes pathogenesis.
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Affiliation(s)
- Anna L. Lang
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Ruy A. Louzada
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Tamayo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Department of Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
| | - Elizabeth Pereira
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Department of Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
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17
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Knuth ER, Foster HR, Jin E, Merrins MJ. Leucine suppresses glucagon secretion from pancreatic islets by directly modulating α-cell cAMP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551113. [PMID: 37577685 PMCID: PMC10418066 DOI: 10.1101/2023.07.31.551113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Objective Pancreatic islets are nutrient sensors that regulate organismal blood glucose homeostasis. Glucagon release from the pancreatic α-cell is important under fasted, fed, and hypoglycemic conditions, yet metabolic regulation of α-cells remains poorly understood. Here, we identified a previously unexplored role for physiological levels of leucine, which is classically regarded as a β-cell fuel, in the intrinsic regulation of α-cell glucagon release. Methods GcgCreERT:CAMPER and GcgCreERT:GCaMP6s mice were generated to perform dynamic, high-throughput functional measurements of α-cell cAMP and Ca2+ within the intact islet. Islet perifusion assays were used for simultaneous, time-resolved measurements of glucagon and insulin release from mouse and human islets. The effects of leucine were compared with glucose and the mitochondrial fuels 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH, non-metabolized leucine analog that activates glutamate dehydrogenase), α-ketoisocaproate (KIC, leucine metabolite), and methyl-succinate (complex II fuel). CYN154806 (Sstr2 antagonist), diazoxide (KATP activator, which prevents Ca2+-dependent exocytosis from α, β, and δ-cells), and dispersed α-cells were used to inhibit islet paracrine signaling and identify α-cell intrinsic effects. Results Mimicking the effect of glucose, leucine strongly suppressed amino acid-stimulated glucagon secretion. Mechanistically, leucine dose-dependently reduced α-cell cAMP at physiological concentrations, with an IC50 of 57, 440, and 1162 μM at 2, 6, and 10 mM glucose, without affecting α-cell Ca2+. Leucine also reduced α-cell cAMP in islets treated with Sstr2 antagonist or diazoxide, as well as dispersed α-cells, indicating an α-cell intrinsic effect. The effect of leucine was matched by KIC and the glutamate dehydrogenase activator BCH, but not methyl-succinate, indicating a dependence on mitochondrial anaplerosis. Glucose, which stimulates anaplerosis via pyruvate carboxylase, had the same suppressive effect on α-cell cAMP but with lower potency. Similarly to mouse islets, leucine suppressed glucagon secretion from human islets under hypoglycemic conditions. Conclusions These findings highlight an important role for physiological levels of leucine in the metabolic regulation of α-cell cAMP and glucagon secretion. Leucine functions primarily through an α-cell intrinsic effect that is dependent on glutamate dehydrogenase, in addition to the well-established α-cell regulation by β/δ-cell paracrine signaling. Our results suggest that mitochondrial anaplerosis-cataplerosis facilitates the glucagonostatic effect of both leucine and glucose, which cooperatively suppress α-cell tone by reducing cAMP.
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Affiliation(s)
- Emily R. Knuth
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Hannah R. Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Erli Jin
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
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18
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Rial SA, Shishani R, Cummings BP, Lim GE. Is 14-3-3 the Combination to Unlock New Pathways to Improve Metabolic Homeostasis and β-Cell Function? Diabetes 2023; 72:1045-1054. [PMID: 37471599 PMCID: PMC10382651 DOI: 10.2337/db23-0094] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/10/2023] [Indexed: 07/22/2023]
Abstract
Since their discovery nearly five decades ago, molecular scaffolds belonging to the 14-3-3 protein family have been recognized as pleiotropic regulators of diverse cellular and physiological functions. With their ability to bind to proteins harboring specific serine and threonine phosphorylation motifs, 14-3-3 proteins can interact with and influence the function of docking proteins, enzymes, transcription factors, and transporters that have essential roles in metabolism and glucose homeostasis. Here, we will discuss the regulatory functions of 14-3-3 proteins that will be of great interest to the fields of metabolism, pancreatic β-cell biology, and diabetes. We first describe how 14-3-3 proteins play a central role in glucose and lipid homeostasis by modulating key pathways of glucose uptake, glycolysis, oxidative phosphorylation, and adipogenesis. This is followed by a discussion of the contributions of 14-3-3 proteins to calcium-dependent exocytosis and how this relates to insulin secretion from β-cells. As 14-3-3 proteins are major modulators of apoptosis and cell cycle progression, we will explore if 14-3-3 proteins represent a viable target for promoting β-cell regeneration and discuss the feasibility of targeting 14-3-3 proteins to treat metabolic diseases such as diabetes. ARTICLE HIGHLIGHTS 14-3-3 proteins are ubiquitously expressed scaffolds with multiple roles in glucose homeostasis and metabolism. 14-3-3ζ regulates adipogenesis via distinct mechanisms and is required for postnatal adiposity and adipocyte function. 14-3-3ζ controls glucose-stimulated insulin secretion from pancreatic β-cells by regulating mitochondrial function and ATP synthesis as well as facilitating cross talk between β-cells and α-cells.
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Affiliation(s)
- Sabri A. Rial
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
- Cardiometabolic Axis, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Rahaf Shishani
- Department of Surgery, Center for Alimentary and Metabolic Sciences, School of Medicine, University of California, Davis, Sacramento, CA
| | - Bethany P. Cummings
- Department of Surgery, Center for Alimentary and Metabolic Sciences, School of Medicine, University of California, Davis, Sacramento, CA
| | - Gareth E. Lim
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
- Cardiometabolic Axis, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
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19
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Enders JD, Thomas S, Lynch P, Jack J, Ryals JM, Puchalska P, Crawford P, Wright DE. ATP-gated potassium channels contribute to ketogenic diet-mediated analgesia in mice. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 14:100138. [PMID: 38099277 PMCID: PMC10719532 DOI: 10.1016/j.ynpai.2023.100138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/01/2023] [Accepted: 07/02/2023] [Indexed: 12/17/2023]
Abstract
Chronic pain is a substantial health burden and options for treating chronic pain remain minimally effective. Ketogenic diets are emerging as well-tolerated, effective therapeutic strategies in preclinical models of chronic pain, especially diabetic neuropathy. We tested whether a ketogenic diet is antinociceptive through ketone oxidation and related activation of ATP-gated potassium (KATP) channels in mice. We demonstrate that consumption of a ketogenic diet for one week reduced evoked nocifensive behaviors (licking, biting, lifting) following intraplantar injection of different noxious stimuli (methylglyoxal, cinnamaldehyde, capsaicin, or Yoda1) in mice. A ketogenic diet also decreased the expression of p-ERK, an indicator of neuronal activation in the spinal cord, following peripheral administration of these stimuli. Using a genetic mouse model with deficient ketone oxidation in peripheral sensory neurons, we demonstrate that protection against methylglyoxal-induced nociception by a ketogenic diet partially depends on ketone oxidation by peripheral neurons. Injection of tolbutamide, a KATP channel antagonist, prevented ketogenic diet-mediated antinociception following intraplantar capsaicin injection. Tolbutamide also restored the expression of spinal activation markers in ketogenic diet-fed, capsaicin-injected mice. Moreover, activation of KATP channels with the KATP channel agonist diazoxide reduced pain-like behaviors in capsaicin-injected, chow-fed mice, similar to the effects observed with a ketogenic diet. Diazoxide also reduced the number of p-ERK+ cells in capsaicin-injected mice. These data support a mechanism that includes neuronal ketone oxidation and activation of KATP channels to provide ketogenic diet-related analgesia. This study also identifies KATP channels as a new target to mimic the antinociceptive effects of a ketogenic diet.
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Affiliation(s)
- Jonathan D. Enders
- Departments of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Sarah Thomas
- Departments of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Paige Lynch
- Departments of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Jarrid Jack
- Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Janelle M. Ryals
- Departments of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Patrycja Puchalska
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, MN 55455, United States
| | - Peter Crawford
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, MN 55455, United States
- Department of Molecular Biology, Biochemistry, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Douglas E. Wright
- Departments of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
- KU Diabetes Institute, University of Kansas Medical Center, Kansas City, KS 66160, United States
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20
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Enders JD, Thomas S, Lynch P, Jack J, Ryals JM, Puchalska P, Crawford P, Wright DE. ATP-Gated Potassium Channels Contribute to Ketogenic Diet-Mediated Analgesia in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541799. [PMID: 37292762 PMCID: PMC10245818 DOI: 10.1101/2023.05.22.541799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chronic pain is a substantial health burden and options for treating chronic pain remain minimally effective. Ketogenic diets are emerging as well-tolerated, effective therapeutic strategies in preclinical models of chronic pain, especially diabetic neuropathy. We tested whether a ketogenic diet is antinociceptive through ketone oxidation and related activation of ATP-gated potassium (KATP) channels in mice. We demonstrate that consumption of a ketogenic diet for one week reduced evoked nocifensive behaviors (licking, biting, lifting) following intraplantar injection of different noxious stimuli (methylglyoxal, cinnamaldehyde, capsaicin, or Yoda1) in mice. A ketogenic diet also decreased the expression of p-ERK, an indicator of neuronal activation in the spinal cord, following peripheral administration of these stimuli. Using a genetic mouse model with deficient ketone oxidation in peripheral sensory neurons, we demonstrate that protection against methylglyoxal-induced nociception by a ketogenic diet partially depends on ketone oxidation by peripheral neurons. Injection of tolbutamide, a KATP channel antagonist, prevented ketogenic diet-mediated antinociception following intraplantar capsaicin injection. Tolbutamide also restored the expression of spinal activation markers in ketogenic diet-fed, capsaicin-injected mice. Moreover, activation of KATP channels with the KATP channel agonist diazoxide reduced pain-like behaviors in capsaicin-injected, chow-fed mice, similar to the effects observed with a ketogenic diet. Diazoxide also reduced the number of p-ERK+ cells in capsaicin-injected mice. These data support a mechanism that includes neuronal ketone oxidation and activation of KATP channels to provide ketogenic diet-related analgesia. This study also identifies KATP channels as a new target to mimic the antinociceptive effects of a ketogenic diet.
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Affiliation(s)
- Jonathan D Enders
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, 66160
| | - Sarah Thomas
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, 66160
| | - Paige Lynch
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, 66160
| | - Jarrid Jack
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, 66160
| | - Janelle M Ryals
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, 66160
| | - Patrycja Puchalska
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, MN, 55455
| | - Peter Crawford
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, MN, 55455
- Department of Molecular Biology, Biochemistry, and Biophysics, University of Minnesota, Minneapolis, MN, 55455
| | - Douglas E Wright
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, 66160
- KU Diabetes Institute, University of Kansas Medical Center, Kansas City, KS, 66160
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