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St-Louis JL, El Jellas K, Velasco K, Slipp BA, Hu J, Helgeland G, Steine SJ, De Jesus DF, Kulkarni RN, Molven A. Deficiency of the metabolic enzyme SCHAD in pancreatic β-cells promotes amino acid-sensitive hypoglycemia. J Biol Chem 2023; 299:104986. [PMID: 37392854 PMCID: PMC10407745 DOI: 10.1016/j.jbc.2023.104986] [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: 06/06/2022] [Revised: 06/02/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023] Open
Abstract
Congenital hyperinsulinism of infancy (CHI) can be caused by a deficiency of the ubiquitously expressed enzyme short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD). To test the hypothesis that SCHAD-CHI arises from a specific defect in pancreatic β-cells, we created genetically engineered β-cell-specific (β-SKO) or hepatocyte-specific (L-SKO) SCHAD knockout mice. While L-SKO mice were normoglycemic, plasma glucose in β-SKO animals was significantly reduced in the random-fed state, after overnight fasting, and following refeeding. The hypoglycemic phenotype was exacerbated when the mice were fed a diet enriched in leucine, glutamine, and alanine. Intraperitoneal injection of these three amino acids led to a rapid elevation in insulin levels in β-SKO mice compared to controls. Consistently, treating isolated β-SKO islets with the amino acid mixture potently enhanced insulin secretion compared to controls in a low-glucose environment. RNA sequencing of β-SKO islets revealed reduced transcription of β-cell identity genes and upregulation of genes involved in oxidative phosphorylation, protein metabolism, and Ca2+ handling. The β-SKO mouse offers a useful model to interrogate the intra-islet heterogeneity of amino acid sensing given the very variable expression levels of SCHAD within different hormonal cells, with high levels in β- and δ-cells and virtually absent α-cell expression. We conclude that the lack of SCHAD protein in β-cells results in a hypoglycemic phenotype characterized by increased sensitivity to amino acid-stimulated insulin secretion and loss of β-cell identity.
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Affiliation(s)
- Johanna L St-Louis
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA; Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway
| | - Khadija El Jellas
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA; Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway
| | - Kelly Velasco
- Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway
| | - Brittany A Slipp
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA
| | - Jiang Hu
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA
| | - Geir Helgeland
- Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway
| | - Solrun J Steine
- Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway
| | - Dario F De Jesus
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA; Harvard Stem Cell Institute, Boston, USA
| | - Rohit N Kulkarni
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, USA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA; Harvard Stem Cell Institute, Boston, USA
| | - Anders Molven
- Department of Clinical Medicine, Gade Laboratory for Pathology, University of Bergen, Bergen, Norway; Department of Pathology, Haukeland University Hospital, Bergen, Norway; Section for Cancer Genomics, Haukeland University Hospital, Bergen, Norway.
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2
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Amoedo ND, Sarlak S, Obre E, Esteves P, Bégueret H, Kieffer Y, Rousseau B, Dupis A, Izotte J, Bellance N, Dard L, Redonnet-Vernhet I, Punzi G, Rodrigues MF, Dumon E, Mafhouf W, Guyonnet-Dupérat V, Gales L, Palama T, Bellvert F, Dugot-Senan N, Claverol S, Baste JM, Lacombe D, Rezvani HR, Pierri CL, Mechta-Grigoriou F, Thumerel M, Rossignol R. Targeting the mitochondrial trifunctional protein restrains tumor growth in oxidative lung carcinomas. J Clin Invest 2021; 131:133081. [PMID: 33393495 DOI: 10.1172/jci133081] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/21/2020] [Indexed: 12/15/2022] Open
Abstract
Metabolic reprogramming is a common hallmark of cancer, but a large variability in tumor bioenergetics exists between patients. Using high-resolution respirometry on fresh biopsies of human lung adenocarcinoma, we identified 2 subgroups reflected in the histologically normal, paired, cancer-adjacent tissue: high (OX+) mitochondrial respiration and low (OX-) mitochondrial respiration. The OX+ tumors poorly incorporated [18F]fluorodeoxy-glucose and showed increased expression of the mitochondrial trifunctional fatty acid oxidation enzyme (MTP; HADHA) compared with the paired adjacent tissue. Genetic inhibition of MTP altered OX+ tumor growth in vivo. Trimetazidine, an approved drug inhibitor of MTP used in cardiology, also reduced tumor growth and induced disruption of the physical interaction between the MTP and respiratory chain complex I, leading to a cellular redox and energy crisis. MTP expression in tumors was assessed using histology scoring methods and varied in negative correlation with [18F]fluorodeoxy-glucose incorporation. These findings provide proof-of-concept data for preclinical, precision, bioenergetic medicine in oxidative lung carcinomas.
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Affiliation(s)
- Nivea Dias Amoedo
- CELLOMET, Bordeaux, France.,INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Saharnaz Sarlak
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Emilie Obre
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Pauline Esteves
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Hugues Bégueret
- Bordeaux University, Bordeaux, France.,Pathology Department, Haut-Lévèque Hospital, CHU Bordeaux, Bordeaux, France
| | - Yann Kieffer
- Stress and Cancer Laboratory, Curie Institute - INSERM U830, Paris, France
| | - Benoît Rousseau
- INSERM U1211, Bordeaux, France.,Transgenic Animal Facility A2, University of Bordeaux, Bordeaux, France
| | - Alexis Dupis
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Julien Izotte
- INSERM U1211, Bordeaux, France.,Transgenic Animal Facility A2, University of Bordeaux, Bordeaux, France
| | - Nadège Bellance
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Laetitia Dard
- CELLOMET, Bordeaux, France.,INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Isabelle Redonnet-Vernhet
- CELLOMET, Bordeaux, France.,INSERM U1211, Bordeaux, France.,Biochemistry Department, Pellegrin Hospital, CHU Bordeaux, Bordeaux, France
| | - Giuseppe Punzi
- Laboratory of Biochemistry and Molecular Biology, University of Bari,Bari, Italy
| | | | - Elodie Dumon
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | - Walid Mafhouf
- Bordeaux University, Bordeaux, France.,INSERM U1035, Bordeaux, France
| | | | - Lara Gales
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National des Sciences Appliquées (INSA)/CNRS 5504 - UMR INSA/Institut National de la Recherche Agronomique (INRA) 792, Toulouse, France
| | - Tony Palama
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National des Sciences Appliquées (INSA)/CNRS 5504 - UMR INSA/Institut National de la Recherche Agronomique (INRA) 792, Toulouse, France
| | - Floriant Bellvert
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National des Sciences Appliquées (INSA)/CNRS 5504 - UMR INSA/Institut National de la Recherche Agronomique (INRA) 792, Toulouse, France
| | | | - Stéphane Claverol
- Bordeaux University, Bordeaux, France.,Functional Genomics Center (CGFB), Proteomics Facility, Bordeaux, France
| | - Jean-Marc Baste
- Thoracic Surgery, Haut-Lévèque Hospital, CHU Bordeaux, Bordeaux, France
| | - Didier Lacombe
- INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
| | | | - Ciro Leonardo Pierri
- Laboratory of Biochemistry and Molecular Biology, University of Bari,Bari, Italy
| | | | - Matthieu Thumerel
- Thoracic Surgery, Haut-Lévèque Hospital, CHU Bordeaux, Bordeaux, France
| | - Rodrigue Rossignol
- CELLOMET, Bordeaux, France.,INSERM U1211, Bordeaux, France.,Bordeaux University, Bordeaux, France
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3
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Peoples JN, Ghazal N, Duong DM, Hardin KR, Manning JR, Seyfried NT, Faundez V, Kwong JQ. Loss of the mitochondrial phosphate carrier SLC25A3 induces remodeling of the cardiac mitochondrial protein acylome. Am J Physiol Cell Physiol 2021; 321:C519-C534. [PMID: 34319827 DOI: 10.1152/ajpcell.00156.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria are recognized as signaling organelles because, under stress, mitochondria can trigger various signaling pathways to coordinate the cell's response. The specific pathway(s) engaged by mitochondria in response to mitochondrial energy defects in vivo and in high-energy tissues like the heart are not fully understood. Here, we investigated cardiac pathways activated in response to mitochondrial energy dysfunction by studying mice with cardiomyocyte-specific loss of the mitochondrial phosphate carrier (SLC25A3), an established model that develops cardiomyopathy as a result of defective mitochondrial ATP synthesis. Mitochondrial energy dysfunction induced a striking pattern of acylome remodeling, with significantly increased post-translational acetylation and malonylation. Mass spectrometry-based proteomics further revealed that energy dysfunction-induced remodeling of the acetylome and malonylome preferentially impacts mitochondrial proteins. Acetylation and malonylation modified a highly interconnected interactome of mitochondrial proteins, and both modifications were present on the enzyme isocitrate dehydrogenase 2 (IDH2). Intriguingly, IDH2 activity was enhanced in SLC25A3-deleted mitochondria, and further study of IDH2 sites targeted by both acetylation and malonylation revealed that these modifications can have site-specific and distinct functional effects. Finally, we uncovered a novel crosstalk between the two modifications, whereby mitochondrial energy dysfunction-induced acetylation of sirtuin 5 (SIRT5), inhibited its function. Because SIRT5 is a mitochondrial deacylase with demalonylase activity, this finding suggests that acetylation can modulate the malonylome. Together, our results position acylations as an arm of the mitochondrial response to energy dysfunction and suggest a mechanism by which focal disruption to the energy production machinery can have an expanded impact on global mitochondrial function.
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Affiliation(s)
- Jessica N Peoples
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Nasab Ghazal
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Duc M Duong
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States
| | - Katherine R Hardin
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, United States
| | - Janet R Manning
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States
| | - Victor Faundez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, United States.,Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
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4
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Velasco K, St-Louis JL, Hovland HN, Thompson N, Ottesen Å, Choi MH, Pedersen L, Njølstad PR, Arnesen T, Fjeld K, Aukrust I, Myklebust LM, Molven A. Functional evaluation of 16 SCHAD missense variants: Only amino acid substitutions causing congenital hyperinsulinism of infancy lead to loss-of-function phenotypes in vitro. J Inherit Metab Dis 2021; 44:240-252. [PMID: 32876354 DOI: 10.1002/jimd.12309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 12/26/2022]
Abstract
Short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD), encoded by the HADH gene, is a ubiquitously expressed mitochondrial enzyme involved in fatty acid oxidation. This protein also plays a role in insulin secretion as recessive HADH mutations cause congenital hyperinsulinism of infancy (CHI) via loss of an inhibitory interaction with glutamate dehydrogenase (GDH). Here, we present a functional evaluation of 16 SCHAD missense variants identified either in CHI patients or by high-throughput sequencing projects in various populations. To avoid interactions with endogenously produced SCHAD protein, we assessed protein stability, subcellular localization, and GDH interaction in a SCHAD knockout HEK293 cell line constructed by CRISPR-Cas9 methodology. We also established methods for efficient SCHAD expression and purification in E. coli, and tested enzymatic activity of the variants. Our analyses showed that rare variants of unknown significance identified in populations generally had similar properties as normal SCHAD. However, the CHI-associated variants p.Gly34Arg, p.Ile184Phe, p.Pro258Leu, and p.Gly303Ser were unstable with low protein levels detectable when expressed in HEK293 cells. Moreover, CHI variants p.Lys136Glu, p.His170Arg, and p.Met188Val presented normal protein levels but displayed clearly impaired enzymatic activity in vitro, and their interaction with GDH appeared reduced. Our results suggest that pathogenic missense variants of SCHAD either make the protein target of a post-translational quality control system or can impair the function of SCHAD without influencing its steady-state protein level. We did not find any evidence that rare SCHAD missense variants observed only in the general population and not in CHI patients are functionally affected.
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Affiliation(s)
- Kelly Velasco
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Johanna L St-Louis
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Henrikke N Hovland
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Nels Thompson
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Åsta Ottesen
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Man Hung Choi
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Line Pedersen
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Pål R Njølstad
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway
| | - Thomas Arnesen
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Department of Surgery, Haukeland University Hospital, Bergen, Norway
| | - Karianne Fjeld
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Ingvild Aukrust
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Line M Myklebust
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Anders Molven
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
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5
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Abstract
This chapter focuses on the methods to measure unique metabolites, specific enzymes, and metabolic flux in fatty acid β-oxidation, and on biochemical assays of tricarboxylic acid (TCA) cycle enzymes and the pyruvate dehydrogenase complex. These assays play an important role in the diagnosis of genetic diseases, newborn screening, and in cancer and metabolism research. The rationale, protocol, pros and cons, and alternative methods are discussed. Nevertheless, each laboratory should adapt the preferred method optimizing sample preparation and assay conditions for linearity and a low signal-to-noise ratio. The reader is also referred to the additional literature citing methods and clinical descriptions of the various diseases.
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6
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Mathioudakis L, Bourbouli M, Daklada E, Kargatzi S, Michaelidou K, Zaganas I. Localization of Human Glutamate Dehydrogenases Provides Insights into Their Metabolic Role and Their Involvement in Disease Processes. Neurochem Res 2018; 44:170-187. [PMID: 29943084 DOI: 10.1007/s11064-018-2575-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Abstract
Glutamate dehydrogenase (GDH) catalyzes the reversible deamination of L-glutamate to α-ketoglutarate and ammonia. In mammals, GDH contributes to important processes such as amino acid and carbohydrate metabolism, energy production, ammonia management, neurotransmitter recycling and insulin secretion. In humans, two isoforms of GDH are found, namely hGDH1 and hGDH2, with the former being ubiquitously expressed and the latter found mainly in brain, testis and kidney. These two iso-enzymes display highly divergent allosteric properties, especially concerning their basal activity, ADP activation and GTP inhibition. On the other hand, both enzymes are thought to predominantly localize in the mitochondrial matrix, even though alternative localizations have been proposed. To further study the subcellular localization of the two human iso-enzymes, we created HEK293 cell lines stably over-expressing hGDH1 and hGDH2. In these cell lines, immunofluorescence and enzymatic analyses verified the overexpression of both hGDH1 and hGDH2 iso-enzymes, whereas subcellular fractionation followed by immunoblotting showed their predominantly mitochondrial localization. Given that previous studies have only indirectly compared the subcellular localization of the two iso-enzymes, we co-expressed them tagged with different fluorescent dyes (green and red fluorescent protein for hGDH1 and hGDH2, respectively) and found them to co-localize. Despite the wealth of information related to the functional properties of hGDH1 and hGDH2 and the availability of the hGDH1 structure, there is still an ongoing debate concerning their metabolic role and their involvement in disease processes. Data on the localization of hGDHs, as the ones presented here, could contribute to better understanding of the function of these important human enzymes.
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Affiliation(s)
- Lambros Mathioudakis
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Mara Bourbouli
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Elisavet Daklada
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Sofia Kargatzi
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Kleita Michaelidou
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Zaganas
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece. .,Department of Neurology, University Hospital of Heraklion, Heraklion, Crete, Greece.
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7
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Lu M, Li C. Nutrient sensing in pancreatic islets: lessons from congenital hyperinsulinism and monogenic diabetes. Ann N Y Acad Sci 2017; 1411:65-82. [PMID: 29044608 DOI: 10.1111/nyas.13448] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/05/2017] [Accepted: 07/14/2017] [Indexed: 12/14/2022]
Abstract
Pancreatic beta cells sense changes in nutrients during the cycles of fasting and feeding and release insulin accordingly to maintain glucose homeostasis. Abnormal beta cell nutrient sensing resulting from gene mutations leads to hypoglycemia or diabetes. Glucokinase (GCK) plays a key role in beta cell glucose sensing. As one form of congenital hyperinsulinism (CHI), activating mutations of GCK result in a decreased threshold for glucose-stimulated insulin secretion and hypoglycemia. In contrast, inactivating mutations of GCK result in diabetes, including a mild form (MODY2) and a severe form (permanent neonatal diabetes mellitus (PNDM)). Mutations of beta cell ion channels involved in insulin secretion regulation also alter glucose sensing. Activating or inactivating mutations of ATP-dependent potassium (KATP ) channel genes result in severe but completely opposite clinical phenotypes, including PNDM and CHI. Mutations of the other ion channels, including voltage-gated potassium channels (Kv 7.1) and voltage-gated calcium channels, also lead to abnormal glucose sensing and CHI. Furthermore, amino acids can stimulate insulin secretion in a glucose-independent manner in some forms of CHI, including activating mutations of the glutamate dehydrogenase gene, HDAH deficiency, and inactivating mutations of KATP channel genes. These genetic defects have provided insight into a better understanding of the complicated nature of beta cell fuel-sensing mechanisms.
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Affiliation(s)
- Ming Lu
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics & Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
| | - Changhong Li
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics & Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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8
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Martines ACMF, van Eunen K, Reijngoud DJ, Bakker BM. The promiscuous enzyme medium-chain 3-keto-acyl-CoA thiolase triggers a vicious cycle in fatty-acid beta-oxidation. PLoS Comput Biol 2017; 13:e1005461. [PMID: 28369071 PMCID: PMC5397069 DOI: 10.1371/journal.pcbi.1005461] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/19/2017] [Accepted: 03/16/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial fatty-acid beta-oxidation (mFAO) plays a central role in mammalian energy metabolism. Multiple severe diseases are associated with defects in this pathway. Its kinetic structure is characterized by a complex wiring of which the functional implications have hardly been explored. Repetitive cycles of reversible reactions, each cycle shortening the fatty acid by two carbon atoms, evoke competition between intermediates of different chain lengths for a common set of 'promiscuous' enzymes (enzymes with activity towards multiple substrates). In our validated kinetic model of the pathway, substrate overload causes a steep and detrimental flux decline. Here, we unravel the underlying mechanism and the role of enzyme promiscuity in it. Comparison of alternative model versions elucidated the role of promiscuity of individual enzymes. Promiscuity of the last enzyme of the pathway, medium-chain ketoacyl-CoA thiolase (MCKAT), was both necessary and sufficient to elicit the flux decline. Subsequently, Metabolic Control Analysis revealed that MCKAT had insufficient capacity to cope with high substrate influx. Next, we quantified the internal metabolic regulation, revealing a vicious cycle around MCKAT. Upon substrate overload, MCKAT's ketoacyl-CoA substrates started to accumulate. The unfavourable equilibrium constant of the preceding enzyme, medium/short-chain hydroxyacyl-CoA dehydrogenase, worked as an amplifier, leading to accumulation of upstream CoA esters, including acyl-CoA esters. These acyl-CoA esters are at the same time products of MCKAT and inhibited its already low activity further. Finally, the accumulation of CoA esters led to a sequestration of free CoA. CoA being a cofactor for MCKAT, its sequestration limited the MCKAT activity even further, thus completing the vicious cycle. Since CoA is also a substrate for distant enzymes, it efficiently communicated the 'traffic jam' at MCKAT to the entire pathway. This novel mechanism provides a basis to explore the role of mFAO in disease and elucidate similar principles in other pathways of lipid metabolism.
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Affiliation(s)
- Anne-Claire M. F. Martines
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Karen van Eunen
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Dirk-Jan Reijngoud
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Barbara M. Bakker
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, The Netherlands
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9
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Caira S, Iannelli A, Sciarrillo R, Picariello G, Renzone G, Scaloni A, Addeo P. Differential representation of liver proteins in obese human subjects suggests novel biomarkers and promising targets for drug development in obesity. J Enzyme Inhib Med Chem 2017; 32:672-682. [PMID: 28274171 PMCID: PMC6009959 DOI: 10.1080/14756366.2017.1292262] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The proteome of liver biopsies from human obese (O) subjects has been compared to those of nonobese (NO) subjects using two-dimensional gel electrophoresis (2-DE). Differentially represented proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS)-based peptide mass fingerprinting (PMF) and nanoflow-liquid chromatography coupled to electrospray-tandem mass spectrometry (nLC-ESI-MS/MS). Overall, 61 gene products common to all of the liver biopsies were identified within 65 spots, among which 25 ones were differently represented between O and NO subjects. In particular, over-representation of short-chain acyl-CoA dehydrogenase, Δ(3,5)-Δ(2,4)dienoyl-CoA isomerase, acetyl-CoA acetyltransferase, glyoxylate reductase/hydroxypyruvate reductase, fructose-biphosphate aldolase B, peroxiredoxin I, protein DJ-1, catalase, α- and β-hemoglobin subunits, 3-mercaptopyruvate S-transferase, calreticulin, aminoacylase 1, phenazine biosynthesis-like domain-containing protein and a form of fatty acid-binding protein, together with downrepresentation of glutamate dehydrogenase, glutathione S-transferase A1, S-adenosylmethionine synthase 1A and a form of apolipoprotein A-I, was associated with the obesity condition. Some of these metabolic enzymes and antioxidant proteins have already been identified as putative diagnostic markers of liver dysfunction in animal models of steatosis or obesity, suggesting additional investigations on their role in these syndromes. Their differential representation in human liver was suggestive of their consideration as obesity human biomarkers and for the development of novel antiobesity drugs.
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Affiliation(s)
- Simonetta Caira
- a Proteomics and Mass Spectrometry Laboratory , ISPAAM, National Research Council , Naples , Italy
| | - Antonio Iannelli
- b Département de Chirurgie Digestive , Centre Hospitalier Universitarie de Nice , Nice , France
| | - Rosaria Sciarrillo
- c Dipartimento di Scienze e Tecnologie , Università degli Studi del Sannio , Benevento , Italy
| | | | - Giovanni Renzone
- a Proteomics and Mass Spectrometry Laboratory , ISPAAM, National Research Council , Naples , Italy
| | - Andrea Scaloni
- a Proteomics and Mass Spectrometry Laboratory , ISPAAM, National Research Council , Naples , Italy
| | - Pietro Addeo
- e Service de Chirurgie Hépatique, Pancréatique, Biliaire et Transplantation, Pôle des Pathologies Digestives, Hépatiques et de la Transplantation, Hôpital de Hautepierre , Université de Strasbourg, Hôpitaux Universitaires de Strasbourg , Strasbourg , France
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Combined defects in oxidative phosphorylation and fatty acid β-oxidation in mitochondrial disease. Biosci Rep 2016; 36:BSR20150295. [PMID: 26839416 PMCID: PMC4793296 DOI: 10.1042/bsr20150295] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/02/2016] [Indexed: 12/20/2022] Open
Abstract
Mitochondria provide the main source of energy to eukaryotic cells, oxidizing fats and sugars to generate ATP. Mitochondrial fatty acid β-oxidation (FAO) and oxidative phosphorylation (OXPHOS) are two metabolic pathways which are central to this process. Defects in these pathways can result in diseases of the brain, skeletal muscle, heart and liver, affecting approximately 1 in 5000 live births. There are no effective therapies for these disorders, with quality of life severely reduced for most patients. The pathology underlying many aspects of these diseases is not well understood; for example, it is not clear why some patients with primary FAO deficiencies exhibit secondary OXPHOS defects. However, recent findings suggest that physical interactions exist between FAO and OXPHOS proteins, and that these interactions are critical for both FAO and OXPHOS function. Here, we review our current understanding of the interactions between FAO and OXPHOS proteins and how defects in these two metabolic pathways contribute to mitochondrial disease pathogenesis.
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Abstract
Transient multienzyme and/or multiprotein complexes (metabolons) direct substrates toward specific pathways and can significantly influence the metabolism of glutamate and glutamine in the brain. Glutamate is the primary excitatory neurotransmitter in brain. This neurotransmitter has essential roles in normal brain function including learning and memory. Metabolism of glutamate involves the coordinated activity of astrocytes and neurons and high affinity transporter proteins that are selectively distributed on these cells. This chapter describes known and possible metabolons that affect the metabolism of glutamate and related compounds in the brain, as well as some factors that can modulate the association and dissociation of such complexes, including protein modifications by acylation reactions (e.g., acetylation, palmitoylation, succinylation, SUMOylation, etc.) of specific residues. Development of strategies to modulate transient multienzyme and/or enzyme-protein interactions may represent a novel and promising therapeutic approach for treatment of diseases involving dysregulation of glutamate metabolism.
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Sakai C, Yamaguchi S, Sasaki M, Miyamoto Y, Matsushima Y, Goto YI. ECHS1 mutations cause combined respiratory chain deficiency resulting in Leigh syndrome. Hum Mutat 2015; 36:232-9. [PMID: 25393721 DOI: 10.1002/humu.22730] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/05/2014] [Indexed: 12/31/2022]
Abstract
The human ECHS1 gene encodes the short-chain enoyl coenzyme A hydratase, the enzyme that catalyzes the second step of β-oxidation of fatty acids in the mitochondrial matrix. We report on a boy with ECHS1 deficiency who was diagnosed with Leigh syndrome at 21 months of age. The patient presented with hypotonia, metabolic acidosis, and developmental delay. A combined respiratory chain deficiency was also observed. Targeted exome sequencing of 776 mitochondria-associated genes encoded by nuclear DNA identified compound heterozygous mutations in ECHS1. ECHS1 protein expression was severely depleted in the patient's skeletal muscle and patient-derived myoblasts; a marked decrease in enzyme activity was also evident in patient-derived myoblasts. Immortalized patient-derived myoblasts that expressed exogenous wild-type ECHS1 exhibited the recovery of the ECHS1 activity, indicating that the gene defect was pathogenic. Mitochondrial respiratory complex activity was also mostly restored in these cells, suggesting that there was an unidentified link between deficiency of ECHS1 and respiratory chain. Here, we describe the patient with ECHS1 deficiency; these findings will advance our understanding not only the pathology of mitochondrial fatty acid β-oxidation disorders, but also the regulation of mitochondrial metabolism.
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Affiliation(s)
- Chika Sakai
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
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Lin SL, Lin TY, Fuh MR. Microfluidic chip-based liquid chromatography coupled to mass spectrometry for determination of small molecules in bioanalytical applications: An update. Electrophoresis 2013; 35:1275-84. [DOI: 10.1002/elps.201300415] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/07/2013] [Accepted: 10/08/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Shu-Ling Lin
- Department of Chemistry; Soochow University; Taipei Taiwan
| | | | - Ming-Ren Fuh
- Department of Chemistry; Soochow University; Taipei Taiwan
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Zhang T, Li C. Mechanisms of amino acid-stimulated insulin secretion in congenital hyperinsulinism. Acta Biochim Biophys Sin (Shanghai) 2013; 45:36-43. [PMID: 23212075 DOI: 10.1093/abbs/gms107] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The role of amino acids in the regulation of insulin secretion in pancreatic beta-cells is highlighted in three forms of congenital hyperinsulinism (HI), namely gain-of-function mutations of glutamate dehydrogenase (GDH), loss-of-function mutations of ATP-dependent potassium channels, and a deficiency of short-chain 3-hydroxyacyl-CoA dehydrogenase. Studies on disease mouse models of HI suggest that amino acid oxidation and signaling effects are the major mechanisms of amino acid-stimulated insulin secretion. Amino acid oxidation via GDH produces ATP and triggers insulin secretion. The signaling effect of amino acids amplifies insulin release after beta-cell depolarization and elevation of cytosolic calcium.
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Affiliation(s)
- Tingting Zhang
- Division of Endocrinology, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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