1
|
Andreozzi F, Mancuso E, Rubino M, Salvatori B, Morettini M, Monea G, Göbl C, Mannino GC, Tura A. Glucagon kinetics assessed by mathematical modelling during oral glucose administration in people spanning from normal glucose tolerance to type 2 diabetes. Front Endocrinol (Lausanne) 2024; 15:1376530. [PMID: 38681771 PMCID: PMC11045965 DOI: 10.3389/fendo.2024.1376530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/28/2024] [Indexed: 05/01/2024] Open
Abstract
Background/Objectives Glucagon is important in the maintenance of glucose homeostasis, with also effects on lipids. In this study, we aimed to apply a recently developed model of glucagon kinetics to determine the sensitivity of glucagon variations (especially, glucagon inhibition) to insulin levels ("alpha-cell insulin sensitivity"), during oral glucose administration. Subjects/Methods We studied 50 participants (spanning from normal glucose tolerance to type 2 diabetes) undergoing frequently sampled 5-hr oral glucose tolerance test (OGTT). The alpha-cell insulin sensitivity and the glucagon kinetics were assessed by a mathematical model that we developed previously. Results The alpha-cell insulin sensitivity parameter (named SGLUCA; "GLUCA": "glucagon") was remarkably variable among participants (CV=221%). SGLUCA was found inversely correlated with the mean glycemic values, as well as with 2-hr glycemia of the OGTT. When stratifying participants into two groups (normal glucose tolerance, NGT, N=28, and impaired glucose regulation/type 2 diabetes, IGR_T2D, N=22), we found that SGLUCA was lower in the latter (1.50 ± 0.50·10-2 vs. 0.26 ± 0.14·10-2 ng·L-1 GLUCA/pmol·L-1 INS, in NGT and IGR_T2D, respectively, p=0.009; "INS": "insulin"). Conclusions The alpha-cell insulin sensitivity is highly variable among subjects, and it is different in groups at different glucose tolerance. This may be relevant for defining personalized treatment schemes, in terms of dietary prescriptions but also for treatments with glucagon-related agents.
Collapse
Affiliation(s)
- Francesco Andreozzi
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Elettra Mancuso
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Mariangela Rubino
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | | | - Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Giuseppe Monea
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Christian Göbl
- Department of Obstetrics and Gynaecology, Medical University of Vienna, Vienna, Austria
- Department of Obstetrics and Gynaecology, Medical University of Graz, Graz, Austria
| | - Gaia Chiara Mannino
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Andrea Tura
- CNR Institute of Neuroscience, Padova, Italy
| |
Collapse
|
2
|
Ferreira B, Heredia A, Serpa J. An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC). Mol Cell Endocrinol 2023; 578:112063. [PMID: 37678603 DOI: 10.1016/j.mce.2023.112063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/16/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.
Collapse
Affiliation(s)
- Bárbara Ferreira
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal
| | - Adrián Heredia
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal; Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz MB, 1649-028, Lisboa, Portugal
| | - Jacinta Serpa
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal.
| |
Collapse
|
3
|
Galsgaard KD, Elmelund E, Johansen CD, Bomholt AB, Kizilkaya HS, Ceutz F, Hunt JE, Kissow H, Winther-Sørensen M, Sørensen CM, Kruse T, Lau JF, Rosenkilde MM, Ørskov C, Christoffersen C, Holst JJ, Wewer Albrechtsen NJ. Glucagon receptor antagonism impairs and glucagon receptor agonism enhances triglycerides metabolism in mice. Mol Metab 2022; 66:101639. [PMID: 36400402 PMCID: PMC9706156 DOI: 10.1016/j.molmet.2022.101639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/06/2022] [Accepted: 11/09/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Treatment with glucagon receptor antagonists (GRAs) reduces blood glucose but causes dyslipidemia and accumulation of fat in the liver. We investigated the acute and chronic effects of glucagon on lipid metabolism in mice. METHODS Chronic effects of glucagon receptor signaling on lipid metabolism were studied using oral lipid tolerance tests (OLTTs) in overnight fasted glucagon receptor knockout (Gcgr-/-) mice, and in C57Bl/6JRj mice treated with a glucagon receptor antibody (GCGR Ab) or a long-acting glucagon analogue (GCGA) for eight weeks. Following treatment, liver tissue was harvested for RNA-sequencing and triglyceride measurements. Acute effects were studied in C57Bl/6JRj mice treated with a GRA or GCGA 1 h or immediately before OLTTs, respectively. Direct effects of glucagon on hepatic lipolysis were studied using isolated perfused mouse liver preparations. To investigate potential effects of GCGA and GRA on gastric emptying, paracetamol was, in separate experiments, administered immediately before OLTTs. RESULTS Plasma triglyceride concentrations increased 2-fold in Gcgr-/- mice compared to their wild-type littermates during the OLTT (P = 0.001). Chronic treatment with GCGR Ab increased, whereas GCGA treatment decreased, plasma triglyceride concentrations during OLTTs (P < 0.05). Genes involved in lipid metabolism were upregulated upon GCGR Ab treatment while GCGA treatment had opposite effects. Acute GRA and GCGA treatment, respectively, increased (P = 0.02) and decreased (P = 0.003) plasma triglyceride concentrations during OLTTs. Glucagon stimulated hepatic lipolysis, evident by an increase in free fatty acid concentrations in the effluent from perfused mouse livers. In line with this, GCGR Ab treatment increased, while GCGA treatment decreased, liver triglyceride concentrations. The effects of glucagon appeared independent of changes in gastric emptying of paracetamol. CONCLUSIONS Glucagon receptor signaling regulates triglyceride metabolism, both chronically and acutely, in mice. These data expand glucagon´s biological role and implicate that intact glucagon signaling is important for lipid metabolism. Glucagon agonism may have beneficial effects on hepatic and peripheral triglyceride metabolism.
Collapse
Affiliation(s)
- Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Elmelund
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian D. Johansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna B. Bomholt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hüsün S. Kizilkaya
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Frederik Ceutz
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jenna E. Hunt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hannelouise Kissow
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte M. Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Kruse
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, DK-2760 Måløv, Denmark
| | - Jesper F. Lau
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, DK-2760 Måløv, Denmark
| | - Mette M. Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina Christoffersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J. Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark,Department of Clinical Biochemistry, Bispebjerg & Frederiksberg Hospitals, University of Copenhagen, 2400 Bispebjerg, Denmark,Corresponding author. Department of Biomedical Sciences and Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, and Department of Clinical Biochemistry, Bispebjerg & Frederiksberg Hospitals, University of Copenhagen, 2400 Bispebjerg, Denmark.
| |
Collapse
|
4
|
Habegger KM. Cross Talk Between Insulin and Glucagon Receptor Signaling in the Hepatocyte. Diabetes 2022; 71:1842-1851. [PMID: 35657690 PMCID: PMC9450567 DOI: 10.2337/dbi22-0002] [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: 03/11/2022] [Accepted: 05/19/2022] [Indexed: 11/13/2022]
Abstract
While the consumption of external energy (i.e., feeding) is essential to life, this action induces a temporary disturbance of homeostasis in an animal. A primary example of this effect is found in the regulation of glycemia. In the fasted state, stored energy is released to maintain physiological glycemic levels. Liver glycogen is liberated to glucose, glycerol and (glucogenic) amino acids are used to build new glucose molecules (i.e., gluconeogenesis), and fatty acids are oxidized to fuel long-term energetic demands. This regulation is driven primarily by the counterregulatory hormones epinephrine, growth hormone, cortisol, and glucagon. Conversely, feeding induces a rapid influx of diverse nutrients, including glucose, that disrupt homeostasis. Consistently, a host of hormonal and neural systems under the coordination of insulin are engaged in the transition from fasting to prandial states to reduce this disruption. The ultimate action of these systems is to appropriately store the newly acquired energy and to return to the homeostatic norm. Thus, at first glance it is tempting to assume that glucagon is solely antagonistic regarding the anabolic effects of insulin. We have been intrigued by the role of glucagon in the prandial transition and have attempted to delineate its role as beneficial or inhibitory to glycemic control. The following review highlights this long-known yet poorly understood hormone.
Collapse
Affiliation(s)
- Kirk M. Habegger
- Comprehensive Diabetes Center and Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| |
Collapse
|
5
|
Göbl C, Morettini M, Salvatori B, Alsalim W, Kahleova H, Ahrén B, Tura A. Temporal Patterns of Glucagon and Its Relationships with Glucose and Insulin following Ingestion of Different Classes of Macronutrients. Nutrients 2022; 14:nu14020376. [PMID: 35057557 PMCID: PMC8780023 DOI: 10.3390/nu14020376] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 01/27/2023] Open
Abstract
Background: glucagon secretion and inhibition should be mainly determined by glucose and insulin levels, but the relative relevance of each factor is not clarified, especially following ingestion of different macronutrients. We aimed to investigate the associations between plasma glucagon, glucose, and insulin after ingestion of single macronutrients or mixed-meal. Methods: thirty-six participants underwent four metabolic tests, based on administration of glucose, protein, fat, or mixed-meal. Glucagon, glucose, insulin, and C-peptide were measured at fasting and for 300 min following food ingestion. We analyzed relationships between time samples of glucagon, glucose, and insulin in each individual, as well as between suprabasal area-under-the-curve of the same variables (ΔAUCGLUCA, ΔAUCGLU, ΔAUCINS) over the whole participants’ cohort. Results: in individuals, time samples of glucagon and glucose were related in only 26 cases (18 direct, 8 inverse relationships), whereas relationship with insulin was more frequent (60 and 5, p < 0.0001). The frequency of significant relationships was different among tests, especially for direct relationships (p ≤ 0.006). In the whole cohort, ΔAUCGLUCA was weakly related to ΔAUCGLU (p ≤ 0.02), but not to ΔAUCINS, though basal insulin secretion emerged as possible covariate. Conclusions: glucose and insulin are not general and exclusive determinants of glucagon secretion/inhibition after mixed-meal or macronutrients ingestion.
Collapse
Affiliation(s)
- Christian Göbl
- Department of Obstetrics and Gynaecology, Medical University of Vienna, 1090 Vienna, Austria;
| | - Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, 60131 Ancona, Italy;
| | | | - Wathik Alsalim
- Department of Clinical Sciences, Faculty of Medicine, Lund University, 22184 Lund, Sweden; (W.A.); (B.A.)
| | - Hana Kahleova
- Physicians Committee for Responsible Medicine, Washington, DC 20016, USA;
| | - Bo Ahrén
- Department of Clinical Sciences, Faculty of Medicine, Lund University, 22184 Lund, Sweden; (W.A.); (B.A.)
| | - Andrea Tura
- CNR Institute of Neuroscience, 35127 Padova, Italy;
- Correspondence: ; Tel.: +39-049-829-5786
| |
Collapse
|
6
|
Stokes J, Freed A, Bornstein R, Su KN, Snell J, Pan A, Sun GX, Park KY, Jung S, Worstman H, Johnson BM, Morgan PG, Sedensky MM, Johnson SC. Mechanisms underlying neonate-specific metabolic effects of volatile anesthetics. eLife 2021; 10:65400. [PMID: 34254587 PMCID: PMC8291971 DOI: 10.7554/elife.65400] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/12/2021] [Indexed: 12/15/2022] Open
Abstract
Volatile anesthetics (VAs) are widely used in medicine, but the mechanisms underlying their effects remain ill-defined. Though routine anesthesia is safe in healthy individuals, instances of sensitivity are well documented, and there has been significant concern regarding the impact of VAs on neonatal brain development. Evidence indicates that VAs have multiple targets, with anesthetic and non-anesthetic effects mediated by neuroreceptors, ion channels, and the mitochondrial electron transport chain. Here, we characterize an unexpected metabolic effect of VAs in neonatal mice. Neonatal blood β-hydroxybutarate (β-HB) is rapidly depleted by VAs at concentrations well below those necessary for anesthesia. β-HB in adults, including animals in dietary ketosis, is unaffected. Depletion of β-HB is mediated by citrate accumulation, malonyl-CoA production by acetyl-CoA carboxylase, and inhibition of fatty acid oxidation. Adults show similar significant changes to citrate and malonyl-CoA, but are insensitive to malonyl-CoA, displaying reduced metabolic flexibility compared to younger animals.
Collapse
Affiliation(s)
- Julia Stokes
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Arielle Freed
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,University of Washington School of Dentistry, Seattle, United States
| | - Rebecca Bornstein
- Department of Pathology, University of Washington, Seattle, United States
| | - Kevin N Su
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, United States
| | - John Snell
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Amanda Pan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Grace X Sun
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Kyung Yeon Park
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Sangwook Jung
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Hailey Worstman
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Brittany M Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, United States
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, United States
| | - Simon C Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Pathology, University of Washington, Seattle, United States.,Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, United States.,Department of Neurology, University of Washington, Seattle, United States
| |
Collapse
|
7
|
Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
Collapse
Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
| |
Collapse
|
8
|
Galsgaard KD. The Vicious Circle of Hepatic Glucagon Resistance in Non-Alcoholic Fatty Liver Disease. J Clin Med 2020; 9:jcm9124049. [PMID: 33333850 PMCID: PMC7765287 DOI: 10.3390/jcm9124049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/08/2023] Open
Abstract
A key criterion for the most common chronic liver disease—non-alcoholic fatty liver disease (NAFLD)—is an intrahepatic fat content above 5% in individuals who are not using steatogenic agents or having significant alcohol intake. Subjects with NAFLD have increased plasma concentrations of glucagon, and emerging evidence indicates that subjects with NAFLD may show hepatic glucagon resistance. For many years, glucagon has been thought of as the counterregulatory hormone to insulin with a primary function of increasing blood glucose concentrations and protecting against hypoglycemia. However, in recent years, glucagon has re-emerged as an important regulator of other metabolic processes including lipid and amino acid/protein metabolism. This review discusses the evidence that in NAFLD, hepatic glucagon resistance may result in a dysregulated lipid and amino acid/protein metabolism, leading to excess accumulation of fat, hyperglucagonemia, and increased oxidative stress contributing to the worsening/progression of NAFLD.
Collapse
Affiliation(s)
- Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; ; Tel.: +45-6044-6145
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| |
Collapse
|
9
|
Janah L, Kjeldsen S, Galsgaard KD, Winther-Sørensen M, Stojanovska E, Pedersen J, Knop FK, Holst JJ, Wewer Albrechtsen NJ. Glucagon Receptor Signaling and Glucagon Resistance. Int J Mol Sci 2019; 20:E3314. [PMID: 31284506 PMCID: PMC6651628 DOI: 10.3390/ijms20133314] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/28/2019] [Accepted: 07/03/2019] [Indexed: 02/08/2023] Open
Abstract
Hundred years after the discovery of glucagon, its biology remains enigmatic. Accurate measurement of glucagon has been essential for uncovering its pathological hypersecretion that underlies various metabolic diseases including not only diabetes and liver diseases but also cancers (glucagonomas). The suggested key role of glucagon in the development of diabetes has been termed the bihormonal hypothesis. However, studying tissue-specific knockout of the glucagon receptor has revealed that the physiological role of glucagon may extend beyond blood-glucose regulation. Decades ago, animal and human studies reported an important role of glucagon in amino acid metabolism through ureagenesis. Using modern technologies such as metabolomic profiling, knowledge about the effects of glucagon on amino acid metabolism has been expanded and the mechanisms involved further delineated. Glucagon receptor antagonists have indirectly put focus on glucagon's potential role in lipid metabolism, as individuals treated with these antagonists showed dyslipidemia and increased hepatic fat. One emerging field in glucagon biology now seems to include the concept of hepatic glucagon resistance. Here, we discuss the roles of glucagon in glucose homeostasis, amino acid metabolism, and lipid metabolism and present speculations on the molecular pathways causing and associating with postulated hepatic glucagon resistance.
Collapse
Affiliation(s)
- Lina Janah
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Sasha Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Elena Stojanovska
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Cardiology, Nephrology and Endocrinology, Nordsjællands Hospital Hillerød, University of Copenhagen, 3400 Hillerød, Denmark
| | - Filip K Knop
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, 2900 Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, 2820 Gentofte, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
- Department of Clinical Biochemistry, Rigshospitalet, 2100 Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark.
| |
Collapse
|
10
|
Galsgaard KD, Pedersen J, Knop FK, Holst JJ, Wewer Albrechtsen NJ. Glucagon Receptor Signaling and Lipid Metabolism. Front Physiol 2019; 10:413. [PMID: 31068828 PMCID: PMC6491692 DOI: 10.3389/fphys.2019.00413] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 03/26/2019] [Indexed: 01/04/2023] Open
Abstract
Glucagon is secreted from the pancreatic alpha cells upon hypoglycemia and stimulates hepatic glucose production. Type 2 diabetes is associated with dysregulated glucagon secretion, and increased glucagon concentrations contribute to the diabetic hyperglycemia. Antagonists of the glucagon receptor have been considered as glucose-lowering therapy in type 2 diabetes patients, but their clinical applicability has been questioned because of reports of therapy-induced increments in liver fat content and increased plasma concentrations of low-density lipoprotein. Conversely, in animal models, increased glucagon receptor signaling has been linked to improved lipid metabolism. Glucagon acts primarily on the liver and by regulating hepatic lipid metabolism glucagon may reduce hepatic lipid accumulation and decrease hepatic lipid secretion. Regarding whole-body lipid metabolism, it is controversial to what extent glucagon influences lipolysis in adipose tissue, particularly in humans. Glucagon receptor agonists combined with glucagon-like peptide 1 receptor agonists (dual agonists) improve dyslipidemia and reduce hepatic steatosis. Collectively, emerging data support an essential role of glucagon for lipid metabolism.
Collapse
Affiliation(s)
- Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Nephrology and Endocrinology, Nordsjællands Hospital Hillerød, University of Copenhagen, Hillerød, Denmark
| | - Filip K Knop
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
11
|
Abstract
Findings from the past 10 years have placed the glucagon-secreting pancreatic α-cell centre stage in the development of diabetes mellitus, a disease affecting almost one in every ten adults worldwide. Glucagon secretion is reduced in patients with type 1 diabetes mellitus, increasing the risk of insulin-induced hypoglycaemia, but is enhanced in type 2 diabetes mellitus, exacerbating the effects of diminished insulin release and action on blood levels of glucose. A better understanding of the mechanisms underlying these changes is therefore an important goal. RNA sequencing reveals that, despite their opposing roles in the control of blood levels of glucose, α-cells and β-cells have remarkably similar patterns of gene expression. This similarity might explain the fairly facile interconversion between these cells and the ability of the α-cell compartment to serve as a source of new β-cells in models of extreme β-cell loss that mimic type 1 diabetes mellitus. Emerging data suggest that GABA might facilitate this interconversion, whereas the amino acid glutamine serves as a liver-derived factor to promote α-cell replication and maintenance of α-cell mass. Here, we survey these developments and their therapeutic implications for patients with diabetes mellitus.
Collapse
Affiliation(s)
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK.
| |
Collapse
|
12
|
Kim KH, Lee MS. FGF21 as a mediator of adaptive responses to stress and metabolic benefits of anti-diabetic drugs. J Endocrinol 2015; 226:R1-16. [PMID: 26116622 DOI: 10.1530/joe-15-0160] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Most hormones secreted from specific organs of the body in response to diverse stimuli contribute to the homeostasis of the whole organism. Fibroblast growth factor 21 (FGF21), a hormone induced by a variety of environmental or metabolic stimuli, plays a crucial role in the adaptive response to these stressful conditions. In addition to its role as a stress hormone, FGF21 appears to function as a mediator of the therapeutic effects of currently available drugs and those under development for treatment of metabolic diseases. In this review, we highlight molecular mechanisms and the functional importance of FGF21 induction in response to diverse stress conditions such as changes of nutritional status, cold exposure, and exercise. In addition, we describe recent findings regarding the role of FGF21 in the pathogenesis and treatment of diabetes associated with obesity, liver diseases, pancreatitis, muscle atrophy, atherosclerosis, cardiac hypertrophy, and diabetic nephropathy. Finally, we discuss the current understanding of the actions of FGF21 as a crucial regulator mediating beneficial metabolic effects of therapeutic agents such as metformin, glucagon/glucagon-like peptide 1 analogues, thiazolidinedione, sirtuin 1 activators, and lipoic acid.
Collapse
Affiliation(s)
- Kook Hwan Kim
- Severance Biomedical Research InstituteDepartment of Internal MedicineYonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Myung-Shik Lee
- Severance Biomedical Research InstituteDepartment of Internal MedicineYonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea Severance Biomedical Research InstituteDepartment of Internal MedicineYonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| |
Collapse
|
13
|
Abstract
Glucagon action is transduced by a G protein-coupled receptor located in liver, kidney, intestinal smooth muscle, brain, adipose tissue, heart, pancreatic β-cells, and placenta. Genetically modified animal models have provided important clues about the role of glucagon and its receptor (Gcgr) beyond glucose control. The PubMed database was searched for articles published between 1995 and 2014 using the key terms glucagon, glucagon receptor, signaling, and animal models. Lack of Gcgr signaling has been associated with: i) hypoglycemic pregnancies, altered placentation, poor fetal growth, and increased fetal-neonatal death; ii) pancreatic glucagon cell hyperplasia and hyperglucagonemia; iii) altered body composition, energy state, and protection from diet-induced obesity; iv) impaired hepatocyte survival; v) altered glucose, lipid, and hormonal milieu; vi) altered metabolic response to prolonged fasting and exercise; vii) reduced gastric emptying and increased intestinal length; viii) altered retinal function; and ix) prevention of the development of diabetes in insulin-deficient mice. Similar phenotypic findings were observed in the hepatocyte-specific deletion of Gcgr. Glucagon action has been involved in the modulation of sweet taste responsiveness, inotropic and chronotropic effects in the heart, satiety, glomerular filtration rate, secretion of insulin, cortisol, ghrelin, GH, glucagon, and somatostatin, and hypothalamic signaling to suppress hepatic glucose production. Glucagon (α) cells under certain conditions can transdifferentiate into insulin (β) cells. These findings suggest that glucagon signaling plays an important role in multiple organs. Thus, treatment options designed to block Gcgr activation in diabetics may have implications beyond glucose homeostasis.
Collapse
Affiliation(s)
- Maureen J Charron
- Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA
| | - Patricia M Vuguin
- Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA
| |
Collapse
|
14
|
Kwan HY, Hu YM, Chan CL, Cao HH, Cheng CY, Pan SY, Tse KW, Wu YC, Yu ZL, Fong WF. Lipidomics identification of metabolic biomarkers in chemically induced hypertriglyceridemic mice. J Proteome Res 2013; 12:1387-98. [PMID: 23336740 DOI: 10.1021/pr3010327] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, we aim to identify the potential biomarkers in hTG pathogenesis in schisandrin B-induced hTG mouse model. To investigate whether these identified biomarkers are only specific to schisandrin B-induced hTG mouse model, we also measured these biomarkers in a high fat diet (HFD)-induced hTG mouse model. We employed a LC/MS/MS-based lipidomic approach for the study. Mouse liver and serum metabolites were separated by reversed phase liquid chromatography. Metabolite candidates were identified by matching with marker retention times, isotope distribution patterns, and high-resolution MS/MS fragmentation patterns. Subsequently, target candidates were quantified by quantitative MS. In the schisandrin B-induced hTG mice, we found that the plasma fatty acids, diglyceroids, and phospholipids were significantly increased. Palmitic acid and stearic acid were increased in the plasma; oleic acid, linoleic acid, linolenic acid, arachidonic acid, and docosahexaenoic acid were increased in both the plasma and the liver. Acetyl-CoA, malonyl-CoA, and succinyl-CoA were increased only in the liver. The changes in levels of these identified markers were also observed in HFD-induced hTG mouse model. The consistent results obtained from both hTG models not only suggest novel biomarkers in hTG pathogenesis, but they also provide insight into the underlying mechanism of the schisandrin B-induced hTG.
Collapse
Affiliation(s)
- Hiu Yee Kwan
- Centre for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Wu G, Zhang L, Li T, Zuniga A, Lopaschuk GD, Li L, Jacobs RL, Vance DE. Choline supplementation promotes hepatic insulin resistance in phosphatidylethanolamine N-methyltransferase-deficient mice via increased glucagon action. J Biol Chem 2012. [PMID: 23179947 DOI: 10.1074/jbc.m112.415117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Biosynthesis of hepatic choline via phosphatidylethanolamine N-methyltransferase (PEMT) plays an important role in the development of type 2 diabetes and obesity. We investigated the mechanism(s) by which choline modulates insulin sensitivity. PEMT wild-type (Pemt(+/+)) and knock-out (Pemt(-/-)) mice received either a high fat diet (HF; 60% kcal of fat) or a high fat, high choline diet (HFHC; 4 g of choline/kg of HF diet) for 1 week. Hepatic insulin signaling and glucose and lipid homeostasis were investigated. Glucose and insulin intolerance occurred in Pemt(-/-) mice fed the HFHC diet, but not in their Pemt(-/-) littermates fed the HF diet. Plasma glucagon was elevated in Pemt(-/-) mice fed the HFHC diet compared with Pemt(-/-) mice fed the HF diet, concomitant with increased hepatic expression of glucagon receptor, phosphorylated AMP-activated protein kinase (AMPK), and phosphorylated insulin receptor substrate 1 at serine 307 (IRS1-s307). Gluconeogenesis and mitochondrial oxidative stress were markedly enhanced, whereas glucose oxidation and triacylglycerol biosynthesis were diminished in Pemt(-/-) mice fed the HFHC diet. A glucagon receptor antagonist (2-aminobenzimidazole) attenuated choline-induced hyperglycemia and insulin intolerance and blunted up-regulation of phosphorylated AMPK and IRS1-s307. Choline induces glucose and insulin intolerance in Pemt(-/-) mice through modulating plasma glucagon and its action in liver.
Collapse
Affiliation(s)
- Gengshu Wu
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Mendez-Figueroa H, Chien EK, Ji H, Nesbitt NL, Bharathi SS, Goetzman E. Effects of labor on placental fatty acid β oxidation. J Matern Fetal Neonatal Med 2012; 26:150-4. [PMID: 22928498 DOI: 10.3109/14767058.2012.722721] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To measure the effect labor exerts on fatty acid (FA) oxidation in term human placentas, and to compare enzymes expression and activity between placenta and liver. METHODS Placental samples were collected: (a) scheduled non-labored cesarean section and (b) normal vaginal delivery at or beyond 37 weeks. Long and medium-chain FA oxidation were measured using (3)H-labeled FA, ATP concentration was measured via commercial kit. Activity and expression levels of 11 FA enzymes were measured and results compared to both human and mouse liver. RESULTS Placentas undergoing labor had significantly decreased palmitate oxidation and ATP levels. Octanoic acid oxidation was 10-fold higher than palmitic acid oxidation. No difference in expression or activity level was detected between the groups. CONCLUSION Term human placentas express all the enzymes required to oxidize FA, at a rate 20-fold lower than liver. FA Oxidation is not likely an important placental energy source during labor. Further work is needed to determine the functionality of this pathway in placenta.
Collapse
Affiliation(s)
- Hector Mendez-Figueroa
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Women and Infants' Hospital of Brown University, Providence, Rhode Island 02903, USA.
| | | | | | | | | | | |
Collapse
|
17
|
Xi L, Matsey G, Odle J. The effect of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on fatty acid oxidation in hepatocytes isolated from neonatal piglets. J Anim Sci Biotechnol 2012; 3:30. [PMID: 23072465 PMCID: PMC3551711 DOI: 10.1186/2049-1891-3-30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 09/17/2012] [Indexed: 01/10/2023] Open
Abstract
In the present study, the effect of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on long-chain fatty acid oxidation by hepatocytes isolated from suckled neonatal pig liver (a low ketogenic and lipogenic tissue) was tested. Incubation of hepatocytes with AICAR (0.5 mM) in the presence of 1 mM of carnitine and 10 mM of glucose for 1 hour at 37°C had no significant effect on total [1-14C]-palmitate (0.5 mM) oxidation (14CO2 and 14C-Acid soluble products (ASP)). Consistent with the fatty acid oxidation, carnitine palmitoyltransferase I activity and inhibition of its activity by malonyl-CoA (10 μM) assayed in cell homogenate also remained constant. However, addition of AICAR to the hepatocytes decreased 14CO2 production by 18% compared to control (p < 0.06). The reduction of labeled carboxylic carbon accumulated in CO2 caused a significant difference in distribution of oxidative products between 14CO2 and 14C-ASP (p < 0.03) compared with the control. It was also noticed that acetyl-CoA carboxylase (ACC) was increased by AICAR (p < 0.03), indicating that ACC might drive acetyl-CoA toward fatty acid synthesis pathway and induce an increase in distribution of fatty acid carbon to 14C-ASP. Addition of insulin to hepatocyte incubations with AICAR did not change the oxidative product distribution between CO2 and ASP, but further promoted ACC activity. The increased ACC activity was 70% higher than in the control group when citrate was absent in the reaction medium and was 30% higher when citrate was present in the medium. Our results suggest that AICAR may affect the distribution of metabolic products from fatty acid oxidation by changing ACC activity in hepatocyte isolated from suckled neonatal piglets; however, the basis for the increase in ACC activity elicited by AICAR is not apparent.
Collapse
Affiliation(s)
- Lin Xi
- Laboratory of Developmental Nutrition, Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA.
| | | | | |
Collapse
|
18
|
Chocron ES, Sayre NL, Holstein D, Saelim N, Ibdah JA, Dong LQ, Zhu X, Cheng SY, Lechleiter JD. The trifunctional protein mediates thyroid hormone receptor-dependent stimulation of mitochondria metabolism. Mol Endocrinol 2012; 26:1117-28. [PMID: 22570332 DOI: 10.1210/me.2011-1348] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We previously demonstrated that the thyroid hormone, T(3), acutely stimulates mitochondrial metabolism in a thyroid hormone receptor (TR)-dependent manner. T(3) has also recently been shown to stimulate mitochondrial fatty acid oxidation (FAO). Here we report that TR-dependent stimulation of metabolism is mediated by the mitochondrial trifunctional protein (MTP), the enzyme responsible for long-chain FAO. Stimulation of FAO was significant in cells that expressed a nonnuclear amino terminus shortened TR isoform (sTR(43)) but not in adult fibroblasts cultured from mice deficient in both TRα and TRβ isoforms (TRα(-/-)β(-/-)). Mouse embryonic fibroblasts deficient in MTP (MTP(-/-)) did not support T(3)-stimulated FAO. Inhibition of fatty-acid trafficking into mitochondria using the AMP-activated protein kinase inhibitor 6-[4-(2-piperidin-1-yl-ethoxy)-phenyl)]-3-pyridin-4-yl-pyrrazolo[1,5-a]-pyrimidine (compound C) or the carnitine palmitoyltransferase 1 inhibitor etomoxir prevented T(3)-stimulated FAO. However, T(3) treatment could increase FAO when AMP-activated protein kinase was maximally activated, indicating an alternate mechanism of T(3)-stimulated FAO exists, even when trafficking is presumably high. MTPα protein levels and higher molecular weight complexes of MTP subunits were increased by T(3) treatment. We suggest that T(3)-induced increases in mitochondrial metabolism are at least in part mediated by a T(3)-shortened TR isoform-dependent stabilization of the MTP complex, which appears to lower MTP subunit turnover.
Collapse
Affiliation(s)
- E Sandra Chocron
- Departments Of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Illsinger S, Janzen N, Sander S, Bode J, Mallunat L, Thomasmeyer R, Hagebölling F, Schmidt KH, Bednarczyk J, Vaske B, Lücke T, Das AM. Energy metabolism in umbilical endothelial cells from preterm and term neonates. J Perinat Med 2011; 39:587-93. [PMID: 21867455 DOI: 10.1515/jpm.2011.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM The aim of this study was to investigate the impact of gestational age on energy metabolism in human umbilical vein endothelial cells (HUVECs) of preterm and term neonates. METHODS Activities of respiratory chain (RC) complexes I-V, citrate synthase (CS), overall mitochondrial fatty acid oxidation (FAO), carnitine palmitoyltransferase 2 (CPT2), glycolytic enzymes as well as energy-rich phosphates in HUVECs from uncomplicated term and preterm pregnancies were measured. Neonatal acylcarnitine profiles were analyzed postpartum. RESULTS Activities of RC complexes II+III, IV, V, and CS were higher in HUVECs from immature pregnancies. Overall FAO did not change, whereas CPT2 activity was higher in term neonates. RC complexes II-V and CS correlated inversely to gestational age, as well as CPT2 activity within the term cohort. Phosphofructokinase activity increased with maturation; lactate dehydrogenase and hexokinase as well as energy-rich phosphates remained constant. In blood, long-chain acylcarnitines were higher in term neonates. CONCLUSIONS Gestational age-dependent differences of energy-providing pathways in HUVECs were shown. Alterations of RC complexes with gestational age may be an adaptive process to cope with metabolic stress during birth; reduced oxidative phosphorylation and high glycolytic activity make HUVECs less susceptible to peripartum hypoxic damage. We hypothesize that HUVECs of premature neonates are metabolically maladapted to birth, which may be responsible for perinatal complications.
Collapse
Affiliation(s)
- Sabine Illsinger
- Clinic for Paediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Hyde MJ, Mostyn A, Modi N, Kemp PR. The health implications of birth by Caesarean section. Biol Rev Camb Philos Soc 2011; 87:229-43. [PMID: 21815988 DOI: 10.1111/j.1469-185x.2011.00195.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Since the first mention of fetal programming of adult health and disease, a plethora of programming events in early life has been suggested. These have included intrauterine and postnatal events, but limited attention has been given to the potential contribution of the birth process to normal physiology and long-term health. Over the last 30 years a growing number of studies have demonstrated that babies born at term by vaginal delivery (VD) have significantly different physiology at birth to those born by Caesarean section (CS), particularly when there has been no exposure to labour, i.e. pre-labour CS (PLCS). This literature is reviewed here and the processes involved in VD that might programme post-natal development are discussed. Some of the effects of CS are short term, but longer term problems are also apparent. We suggest that VD initiates important physiological trajectories and the absence of this stimulus in CS has implications for adult health. There are a number of factors that might plausibly contribute to this programming, one of which is the hormonal surge or "stress response" of VD. Given the increasing incidence of elective PLCS, an understanding of the effects of VD on normal development is crucial.
Collapse
Affiliation(s)
- Matthew J Hyde
- Section of Neonatal Medicine, Department of Medicine, Imperial College London, Chelsea and Westminster Campus, London, UK.
| | | | | | | |
Collapse
|
21
|
Gilibili RR, Kandaswamy M, Sharma K, Giri S, Rajagopal S, Mullangi R. Development and validation of a highly sensitive LC-MS/MS method for simultaneous quantitation of acetyl-CoA and malonyl-CoA in animal tissues. Biomed Chromatogr 2011; 25:1352-9. [PMID: 21381064 DOI: 10.1002/bmc.1608] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 12/10/2010] [Indexed: 11/10/2022]
Abstract
A highly sensitive and specific LC-MS/MS method was developed for simultaneous estimation of acetyl co-enzyme A (ACoA) and malonyl co-enzyme A (MCoA) in surrogate matrix using n-propionyl co-enzyme A as an internal standard (IS). LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. Simple acidification followed by dilution using an assay buffer process was used to extract ACoA, MCoA and IS from surrogate matrix and tissue samples. The total run time was 3 min and the elution of both analytes (ACoA, MCoA) and IS occurred at 1.28 min; this was achieved with a mobile phase consisting of 5 mM ammonium formate (pH 7.5)-acetonitrile (30:70, v/v) delivered at a flow rate of 1 mL/min on a monolithic RP-18e column. A linear response function was established for the range of concentrations 1.09-2187 and 1.09-2193 ng/mL for ACoA and MCoA, respectively. The intra- and inter-day precision values for ACoA and MCoA met the acceptance as per FDA guidelines. ACoA and MCoA were stable in a battery of stability studies viz. bench-top, auto-sampler and long-term. The developed assay was used to quantitate ACoA and MCoA levels in various tissues of rat.
Collapse
|
22
|
Habegger KM, Heppner KM, Geary N, Bartness TJ, DiMarchi R, Tschöp MH. The metabolic actions of glucagon revisited. Nat Rev Endocrinol 2010; 6:689-97. [PMID: 20957001 PMCID: PMC3563428 DOI: 10.1038/nrendo.2010.187] [Citation(s) in RCA: 244] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The initial identification of glucagon as a counter-regulatory hormone to insulin revealed this hormone to be of largely singular physiological and pharmacological purpose. Glucagon agonism, however, has also been shown to exert effects on lipid metabolism, energy balance, body adipose tissue mass and food intake. The ability of glucagon to stimulate energy expenditure, along with its hypolipidemic and satiating effects, in particular, make this hormone an attractive pharmaceutical agent for the treatment of dyslipidemia and obesity. Studies that describe novel preclinical applications of glucagon, alone and in concert with glucagon-like peptide 1 agonism, have revealed potential benefits of glucagon agonism in the treatment of the metabolic syndrome. Collectively, these observations challenge us to thoroughly investigate the physiology and therapeutic potential of insulin's long-known opponent.
Collapse
Affiliation(s)
- Kirk M Habegger
- Department of Medicine, University of Cincinnati, Metabolic Diseases Institute, Office E-217, 2170 East Galbraith Road, Cincinnati, OH 45237, USA
| | | | | | | | | | | |
Collapse
|
23
|
Lin X, Shim K, Odle J. Carnitine palmitoyltransferase I control of acetogenesis, the major pathway of fatty acid {beta}-oxidation in liver of neonatal swine. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1435-43. [PMID: 20237302 DOI: 10.1152/ajpregu.00634.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine the regulation of hepatic acetogenesis in neonatal swine, carnitine palmitoyltransferase I (CPT I) activity was measured in the presence of varying palmitoyl-CoA (substrate) and malonyl-CoA (inhibitor) concentrations, and [1-(14)C]-palmitate oxidation was simultaneously measured. Accumulation rates of (14)C-labeled acetate, ketone bodies, and citric acid cycle intermediates within the acid-soluble products were determined using radio-HPLC. Measurements were conducted in mitochondria isolated from newborn, 24-h (fed or fasted), and 5-mo-old pigs. Acetate rather than ketone bodies was the predominant radiolabeled product, and its production increased twofold with increasing fatty acid oxidation during the first 24-h suckling period. The rate of acetogenesis was directly proportional to CPT I activity. The high activity of CPT I in 24-h-suckling piglets was not attributable to an increase in CPT I gene expression, but rather to a large decrease in the sensitivity of CPT I to malonyl-CoA inhibition, which offset a developmental decrease in affinity of CPT I for palmitoyl-CoA. Specifically, the IC(50) for malonyl-CoA inhibition and K(m) value for palmitoyl-CoA measured in 24-h-suckling pigs were 1.8- and 2.7-fold higher than measured in newborn pigs. The addition of anaplerotic carbon from malate (10 mM) significantly reduced (14)C accumulation in acetate (P < 0.003); moreover, the reduction was much greater in newborn (80%) than in 24-h-fed (72%) and 5-mo-old pigs (55%). The results demonstrate that acetate is the primary product of hepatic mitochondrial beta-oxidation in Sus scrofa and that regulation during early development is mediated primarily via kinetic modulation of CPT I.
Collapse
Affiliation(s)
- Xi Lin
- Laboratory of Developmental Nutrition, Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA
| | | | | |
Collapse
|
24
|
Modulation of the hepatic malonyl-CoA-carnitine palmitoyltransferase 1A partnership creates a metabolic switch allowing oxidation of de novo fatty acids. Biochem J 2009; 420:429-38. [PMID: 19302064 DOI: 10.1042/bj20081932] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Liver mitochondrial beta-oxidation of LCFAs (long-chain fatty acids) is tightly regulated through inhibition of CPT1A (carnitine palmitoyltransferase 1A) by malonyl-CoA, an intermediate of lipogenesis stimulated by glucose and insulin. Moreover, CPT1A sensitivity to malonyl-CoA inhibition varies markedly depending on the physiopathological state of the animal. In the present study, we asked whether an increase in CPT1A activity solely or in association with a decreased malonyl-CoA sensitivity could, even in the presence of high glucose and insulin concentrations, maintain a sustained LCFA beta-oxidation and/or protect from triacylglycerol (triglyceride) accumulation in hepatocytes. We have shown that adenovirus-mediated expression of rat CPT1wt (wild-type CPT1A) and malonyl-CoA-insensitive CPT1mt (CPT1AM593S mutant) in cultured fed rat hepatocytes counteracted the inhibition of oleate beta-oxidation induced by 20 mM glucose/10 nM insulin. Interestingly, the glucose/insulin-induced cellular triacylglycerol accumulation was prevented, both in the presence and absence of exogenous oleate. This resulted from the generation of a metabolic switch allowing beta-oxidation of de novo synthesized LCFAs, which occurred without alteration in glucose oxidation and glycogen synthesis. Moreover, CPT1mt expression was more effective than CPT1wt overexpression to counteract glucose/insulin effects, demonstrating that control of CPT1A activity by malonyl-CoA is an essential driving force for hepatic LCFA metabolic fate. In conclusion, the present study highlights that CPT1A is a prime target to increase hepatic LCFA beta-oxidation and that acting directly on the degree of its malonyl-CoA sensitivity may be a relevant strategy to prevent and/or correct hepatic steatosis.
Collapse
|
25
|
Longuet C, Sinclair EM, Maida A, Baggio LL, Maziarz M, Charron MJ, Drucker DJ. The glucagon receptor is required for the adaptive metabolic response to fasting. Cell Metab 2008; 8:359-71. [PMID: 19046568 PMCID: PMC2593715 DOI: 10.1016/j.cmet.2008.09.008] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Revised: 06/03/2008] [Accepted: 09/12/2008] [Indexed: 10/21/2022]
Abstract
Glucagon receptor (Gcgr) signaling maintains hepatic glucose production during the fasting state; however, the importance of the Gcgr for lipid metabolism is unclear. We show here that fasted Gcgr-/- mice exhibit a significant increase in hepatic triglyceride secretion and fasting increases fatty acid oxidation (FAO) in wild-type (WT) but not in Gcgr-/- mice. Moreover fasting upregulated the expression of FAO-related hepatic mRNA transcripts in Gcgr+/+ but not in Gcgr-/- mice. Exogenous glucagon administration reduced plasma triglycerides in WT mice, inhibited TG synthesis and secretion, and stimulated FA beta oxidation in Gcgr+/+ hepatocytes. The actions of glucagon on TG synthesis and FAO were abolished in PPARalpha-/- hepatocytes. These findings demonstrate that the Gcgr receptor is required for control of lipid metabolism during the adaptive metabolic response to fasting.
Collapse
Affiliation(s)
- Christine Longuet
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | | | | | | | | | | | | |
Collapse
|
26
|
The transcription factor COUP-TFII is negatively regulated by insulin and glucose via Foxo1- and ChREBP-controlled pathways. Mol Cell Biol 2008; 28:6568-79. [PMID: 18765640 DOI: 10.1128/mcb.02211-07] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
COUP-TFII has an important role in regulating metabolism in vivo. We showed this previously by deleting COUP-TFII from pancreatic beta cells in heterozygous mutant mice, which led to abnormal insulin secretion. Here, we report that COUP-TFII expression is reduced in the pancreas and liver of mice refed with a carbohydrate-rich diet and in the pancreas and liver of hyperinsulinemic and hyperglycemic mice. In pancreatic beta cells, COUP-TFII gene expression is repressed by secreted insulin in response to glucose through Foxo1 signaling. Ex vivo COUP-TFII reduces insulin production and secretion. Our results suggest that beta cell insulin secretion is under the control of an autocrine positive feedback loop by alleviating COUP-TFII repression. In hepatocytes, both insulin, through Foxo1, and high glucose concentrations repress COUP-TFII expression. We demonstrate that this negative glucose effect involves ChREBP expression. We propose that COUP-TFII acts in a coordinate fashion to control insulin secretion and glucose metabolism.
Collapse
|
27
|
Gao L, Chiou W, Tang H, Cheng X, Camp HS, Burns DJ. Simultaneous quantification of malonyl-CoA and several other short-chain acyl-CoAs in animal tissues by ion-pairing reversed-phase HPLC/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 853:303-13. [PMID: 17442642 DOI: 10.1016/j.jchromb.2007.03.029] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 01/23/2007] [Accepted: 03/20/2007] [Indexed: 12/01/2022]
Abstract
Malonyl-CoA is a key intermediate involved in lipid synthesis and lipid oxidation. Here, we report on a novel method for the quantification of malonyl-CoA and seven other short-chain acyl-CoAs in various rat and mouse tissues using ion-pairing reversed-phase HPLC/MS. This method is capable of measuring malonyl-CoA, free coenzyme A (CoASH), acetyl-CoA, beta-hydroxyl-butyryl-CoA (HB-CoA), 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA), propionyl-CoA, succinyl-CoA, and isobutyryl-CoA simultaneously with a dynamic linear range over two orders of magnitude in a 7.0 min HPLC gradient run. The lower limit of quantification (LLOQ) was 0.225 pmol for all acyl-CoAs studied, except for HMG-CoA which had a higher LLOQ of 0.90 pmol. The interference of HB-CoA on the quantification of malonyl-CoA in animal tissues was also explored for the first time.
Collapse
Affiliation(s)
- Lan Gao
- Department of Biological Screening, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, United States.
| | | | | | | | | | | |
Collapse
|
28
|
Wallace DM, Haramura M, Cheng JF, Arrhenius T, Nadzan AM. Novel trifluoroacetophenone derivatives as malonyl-CoA decarboxylase inhibitors. Bioorg Med Chem Lett 2007; 17:1127-30. [PMID: 17234415 DOI: 10.1016/j.bmcl.2006.09.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 09/07/2006] [Accepted: 09/08/2006] [Indexed: 10/23/2022]
Abstract
A series of trifluoroacetophenone derivatives were prepared and evaluated as malonyl-CoA decarboxylase (MCD) inhibitors. Some of the 'reverse amide' analogs were found to be potent inhibitors of MCD enzyme activity. The trifluoroacetyl group may interact with the MCD active site as the hydrate in a similar fashion to the hexafluoroisopropanol analogs reported previously. Adding electron-withdrawing groups to the phenyl ring stabilizes the hydrated species and enhances this interaction.
Collapse
Affiliation(s)
- David M Wallace
- Department of Chemistry, Chugai Pharma USA, LLC., 6275 Nancy Ridge Dr., San Diego, CA 92121, USA.
| | | | | | | | | |
Collapse
|
29
|
Harada N, Oda Z, Hara Y, Fujinami K, Okawa M, Ohbuchi K, Yonemoto M, Ikeda Y, Ohwaki K, Aragane K, Tamai Y, Kusunoki J. Hepatic de novo lipogenesis is present in liver-specific ACC1-deficient mice. Mol Cell Biol 2007; 27:1881-8. [PMID: 17210641 PMCID: PMC1820479 DOI: 10.1128/mcb.01122-06] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetyl coenzyme A (acetyl-CoA) carboxylase (ACC) catalyzes carboxylation of acetyl-CoA to form malonyl-CoA. In mammals, two isozymes exist with distinct physiological roles: cytosolic ACC1 participates in de novo lipogenesis (DNL), and mitochondrial ACC2 is involved in negative regulation of mitochondrial beta-oxidation. Since systemic ACC1 null mice were embryonic lethal, to clarify the physiological role of ACC1 in hepatic DNL, we generated the liver-specific ACC1 null mouse by crossbreeding of an Acc1(lox(ex46)) mouse, in which exon 46 of Acc1 was flanked by two loxP sequences and the liver-specific Cre transgenic mouse. In liver-specific ACC1 null mice, neither hepatic Acc1 mRNA nor protein was detected. However, to compensate for ACC1 function, hepatic ACC2 protein and activity were induced 1.4 and 2.2 times, respectively. Surprisingly, hepatic DNL and malonyl-CoA were maintained at the same physiological levels as in wild-type mice. Furthermore, hepatic DNL was completely inhibited by an ACC1/2 dual inhibitor, 5-tetradecyloxyl-2-furancarboxylic acid. These results strongly demonstrate that malonyl-CoA from ACC2 can access fatty acid synthase and become the substrate for the DNL pathway under the unphysiological circumstances that result with ACC1 disruption. Therefore, there does not appear to be strict compartmentalization of malonyl-CoA from either of the ACC isozymes in the liver.
Collapse
Affiliation(s)
- Naomoto Harada
- Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., 3 Okubo, Tsukuba, Ibaraki 300-2611, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Cheng JF, Huang Y, Penuliar R, Nishimoto M, Liu L, Arrhenius T, Yang G, O'leary E, Barbosa M, Barr R, Dyck JRB, Lopaschuk GD, Nadzan AM. Discovery of potent and orally available malonyl-CoA decarboxylase inhibitors as cardioprotective agents. J Med Chem 2006; 49:4055-8. [PMID: 16821767 DOI: 10.1021/jm0605029] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Discovery of 5-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)-4,5-dihydroisoxazole-3-carboxamides as a new class of malonyl-coenzyme A decarboxylase (MCD) inhibitors is described. tert-Butyl 3-(5-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)-4,5-dihydroisoxazole-3-carboxamido)butanoate (5, CBM-301940) exhibited excellent potency and in vivo PK/ADME properties. It is the most powerful stimulant of glucose oxidation reported to date in isolated working rat hearts. Compound 5 improved the cardiac efficiency and function in a rat heart global ischemia/reperfusion model, suggesting MCD inhibitors may be useful for the treatment of ischemic heart diseases.
Collapse
Affiliation(s)
- Jie-Fei Cheng
- Department of Chemistry, Chugai Pharma USA, LLC., 6275 Nancy Ridge Drive, San Diego, California 92121, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Cheng JF, Mak CC, Huang Y, Penuliar R, Nishimoto M, Zhang L, Chen M, Wallace D, Arrhenius T, Chu D, Yang G, Barbosa M, Barr R, Dyck JRB, Lopaschuk GD, Nadzan AM. Heteroaryl substituted bis-trifluoromethyl carbinols as malonyl-CoA decarboxylase inhibitors. Bioorg Med Chem Lett 2006; 16:3484-8. [PMID: 16644218 DOI: 10.1016/j.bmcl.2006.03.100] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Accepted: 03/30/2006] [Indexed: 01/09/2023]
Abstract
A series of heteroaryl-substituted bis-trifluoromethyl carbinols were prepared and evaluated as malonyl-CoA decarboxylase (MCD) inhibitors. Some thiazole-based derivatives showed potent in vitro MCD inhibitory activities and significantly increased glucose oxidation rates in isolated working rat hearts.
Collapse
Affiliation(s)
- Jie-Fei Cheng
- Department of Chemistry and Discovery Biology, Chugai Pharma LLC., 6275 Nancy Ridge Dr., San Diego, CA 92121, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Oey NA, Ruiter JPN, Attié-Bitach T, Ijlst L, Wanders RJA, Wijburg FA. Fatty acid oxidation in the human fetus: implications for fetal and adult disease. J Inherit Metab Dis 2006; 29:71-5. [PMID: 16601871 DOI: 10.1007/s10545-006-0199-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 12/02/2005] [Indexed: 11/28/2022]
Abstract
Studies in the last few years have shown a remarkably high activity of fatty acid oxidation (FAO) enzymes in human placenta. We have recently shown mRNA expression as well as enzymatic activity of long-chain FAO enzymes in the human embryo and fetus. In this study we show activity of the FAO enzymes carnitine palmitoyltranferase 1, medium-chain acyl-CoA dehydrogenase and short-chain hydroxyacyl-CoA dehydrogenase in embryonic and fetal tissues. In addition, we show the presence of different acylcarnitines in fetal liver and kidney, which substantiates the notion that the mitochondrial FAO enzymes are not only present in human fetal tissues but also metabolically active. In a glucose-rich environment FAO might be necessary for additional ATP production from fatty acids, but also for the breakdown of fatty acids that are products of the turnover of membranes in the growing fetus. The importance of FAO in the human embryo and fetus is further stressed by the fact that a higher frequency of prematurity, intrauterine growth retardation, fetal morbidity and intrauterine death is noted in long-chain FAO defects. Furthermore, in animal studies, gestational loss during early embryonic development has been observed as a consequence of disturbed FAO. Finally, there are indications that regulation of activity of FAO during fetal development might not only be important for fetal life but may also have implications for health and disease in adulthood.
Collapse
Affiliation(s)
- Nadia A Oey
- Department of Pediatrics, G8-205, Emma Children's Hospital AMC, Academic Medical Centre, PO Box 22660, NL-1100 DD, Amsterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
33
|
Faye A, Borthwick K, Esnous C, Price N, Gobin S, Jackson V, Zammit V, Girard J, Prip-Buus C. Demonstration of N- and C-terminal domain intramolecular interactions in rat liver carnitine palmitoyltransferase 1 that determine its degree of malonyl-CoA sensitivity. Biochem J 2005; 387:67-76. [PMID: 15498023 PMCID: PMC1134933 DOI: 10.1042/bj20041533] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have previously proposed that changes in malonyl-CoA sensitivity of rat L-CPT1 (liver carnitine palmitoyltransferase 1) might occur through modulation of interactions between its cytosolic N- and C-terminal domains. By using a cross-linking strategy based on the trypsin-resistant folded state of L-CPT1, we have now shown the existence of such N-C (N- and C-terminal domain) intramolecular interactions both in wild-type L-CPT1 expressed in Saccharomyces cerevisiae and in the native L-CPT1 in fed rat liver mitochondria. These N-C intramolecular interactions were found to be either totally (48-h starvation) or partially abolished (streptozotocin-induced diabetes) in mitochondria isolated from animals in which the enzyme displays decreased malonyl-CoA sensitivity. Moreover, increasing the outer membrane fluidity of fed rat liver mitochondria with benzyl alcohol in vitro, which induced malonyl-CoA desensitization, attenuated the N-C interactions. This indicates that the changes in malonyl-CoA sensitivity of L-CPT1 observed in mitochondria from starved and diabetic rats, previously shown to be associated with altered membrane composition in vivo, are partly due to the disruption of N-C interactions. Finally, we show that mutations in the regulatory regions of the N-terminal domain affect the ability of the N terminus to interact physically with the C-terminal domain, irrespective of whether they increased [S24A (Ser24-->Ala)/Q30A] or abrogated (E3A) malonyl-CoA sensitivity. Moreover, we have identified the region immediately N-terminal to transmembrane domain 1 (residues 40-47) as being involved in the chemical N-C cross-linking. These observations provide the first demonstration by a physico-chemical method that L-CPT1 adopts different conformational states that differ in their degree of proximity between the cytosolic N-terminal and the C-terminal domains, and that this determines its degree of malonyl-CoA sensitivity depending on the physiological state.
Collapse
Affiliation(s)
- Audrey Faye
- *Département d'Endocrinologie, Institut Cochin, INSERM U567, CNRS Unité Mixte de Recherche 8104, Université René Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Karen Borthwick
- †Department of Cell Biochemistry, Hannah Research Institute, Ayr, Scotland KA6 5HL, U.K
| | - Catherine Esnous
- *Département d'Endocrinologie, Institut Cochin, INSERM U567, CNRS Unité Mixte de Recherche 8104, Université René Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Nigel T. Price
- †Department of Cell Biochemistry, Hannah Research Institute, Ayr, Scotland KA6 5HL, U.K
| | - Stéphanie Gobin
- *Département d'Endocrinologie, Institut Cochin, INSERM U567, CNRS Unité Mixte de Recherche 8104, Université René Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Vicky N. Jackson
- †Department of Cell Biochemistry, Hannah Research Institute, Ayr, Scotland KA6 5HL, U.K
| | - Victor A. Zammit
- †Department of Cell Biochemistry, Hannah Research Institute, Ayr, Scotland KA6 5HL, U.K
| | - Jean Girard
- *Département d'Endocrinologie, Institut Cochin, INSERM U567, CNRS Unité Mixte de Recherche 8104, Université René Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Carina Prip-Buus
- *Département d'Endocrinologie, Institut Cochin, INSERM U567, CNRS Unité Mixte de Recherche 8104, Université René Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
- To whom correspondence should be addressed (email )
| |
Collapse
|
34
|
Oey NA, den Boer MEJ, Wijburg FA, Vekemans M, Augé J, Steiner C, Wanders RJA, Waterham HR, Ruiter JPN, Attié-Bitach T. Long-chain fatty acid oxidation during early human development. Pediatr Res 2005; 57:755-9. [PMID: 15845636 DOI: 10.1203/01.pdr.0000161413.42874.74] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Patients with very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)/mitochondrial trifunctional protein (MTP) deficiency, disorders of the mitochondrial long-chain fatty acid oxidation, can present with hypoketotic hypoglycemia, rhabdomyolysis, and cardiomyopathy. In addition, patients with LCHAD/MTP deficiency may suffer from retinopathy and peripheral neuropathy. Until recently, there was no indication of intrauterine morbidity in these disorders. This observation was in line with the widely accepted view that fatty acid oxidation (FAO) does not play a significant role during fetal life. However, the high incidence of the gestational complications acute fatty liver of pregnancy and hemolysis, elevated liver enzymes, and low platelets syndrome observed in mothers carrying a LCHAD/MTP-deficient child and the recent reports of fetal hydrops due to cardiomyopathy in MTP deficiency, as well as the high incidence of intrauterine growth retardation in children with LCHAD/MTP deficiency, suggest that FAO may play an important role during fetal development. In this study, using in situ hybridization of the VLCAD and the LCHAD mRNA, we report on the expression of genes involved in the mitochondrial oxidation of long-chain fatty acids during early human development. Furthermore, we measured the enzymatic activity of the VLCAD, LCHAD, and carnitine palmitoyl-CoA transferase 2 (CPT2) enzymes in different human fetal tissues. Human embryos (at d 35 and 49 of development) and separate tissues (5-20 wk of development) were used. The results show a strong expression of VLCAD and LCHAD mRNA and a high enzymatic activity of VLCAD, LCHAD, and CPT2 in a number of tissues, such as liver and heart. In addition, high expression of LCHAD mRNA was observed in the neural retina and CNS. The observed pattern of expression during early human development is well in line with the spectrum of clinical signs and symptoms reported in patients with VLCAD or LCHAD/MTP deficiency.
Collapse
Affiliation(s)
- Nadia A Oey
- Department of Pediatrics, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Gondret F, Damon M, Jadhao SB, Houdebine LM, Herpin P, Hocquette JF. Age-related changes in glucose utilization and fatty acid oxidation. J Muscle Res Cell Motil 2004; 25:405-10. [PMID: 15548870 DOI: 10.1007/s10974-004-2768-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The optimal utilization of energy substrates in muscle fibers is of primary importance for muscle contraction and whole body physiology. This study aimed to investigate the age-related changes in some indicators of glucose catabolism and fatty acid oxidation in muscles of growing rabbits. Longissimus lumborum (fast-twitch, LL) and semimembranosus proprius (slow-twitch, SMP) muscles were collected at 10 or 20 weeks of age ( n=6 per age). Glucose transporter GLUT4 content was investigated by immunoblot assay. Activity levels of five enzymes were measured: lactate dehydrogenase (LDH) and phosphofructokinase (PFK) for glycolysis; citrate synthase (CS), isocitrate dehydrogenase (ICDH) and -3-hydroxyacyl-coenzyme A dehydrogenase (HAD) for oxidation. Mitochondrial and peroxisomal oxidation rates were assessed on fresh homogenates using [1-14C]-oleate as substrate. At both ages, mitochondrial and peroxisomal oxidations rates, as well as activities of oxidative enzymes were higher in SMP than in LL. In both muscles, the apparent rate of fatty acid oxidation by the mitochondria did not differ between the two ages. However, a decrease in the activities of the three oxidative enzymes was observed in LL, whereas activities of CS and HAD and peroxisomal oxidation rate of oleate increased between the two ages in SMP muscle. In both muscles, LDH activity increased between 10 and 20 weeks, without variations in glucose uptake (GLUT4 transporter content) and in the first step of glucose utilization (PFK activity). In conclusion, mitochondrial oxidation rate of fatty acids and activities of selected mitochondrial enzymes were largely unrelated. Moreover, regulation of energy metabolism with advancing age differed between muscle types.
Collapse
Affiliation(s)
- Florence Gondret
- INRA, Unité Mixte de Recherches sur le Veau et le Porc, Saint Gilles, France.
| | | | | | | | | | | |
Collapse
|
36
|
Shekhawat P, Bennett MJ, Sadovsky Y, Nelson DM, Rakheja D, Strauss AW. Human placenta metabolizes fatty acids: implications for fetal fatty acid oxidation disorders and maternal liver diseases. Am J Physiol Endocrinol Metab 2003; 284:E1098-105. [PMID: 12582009 DOI: 10.1152/ajpendo.00481.2002] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The role of fat metabolism during human pregnancy and in placental growth and function is poorly understood. Mitochondrial fatty acid oxidation disorders in an affected fetus are associated with maternal diseases of pregnancy, including preeclampsia, acute fatty liver of pregnancy, and the hemolysis, elevated liver enzymes, and low platelets syndrome called HELLP. We have investigated the developmental expression and activity of six fatty acid beta-oxidation enzymes at various gestational-age human placentas. Placental specimens exhibited abundant expression of all six enzymes, as assessed by immunohistochemical and immunoblot analyses, with greater staining in syncytiotrophoblasts compared with other placental cell types. beta-Oxidation enzyme activities in placental tissues were higher early in gestation and lower near term. Trophoblast cells in culture oxidized tritium-labeled palmitate and myristate in substantial amounts, indicating that the human placenta utilizes fatty acids as a significant metabolic fuel. Thus human placenta derives energy from fatty acid oxidation, providing a potential explanation for the association of fetal fatty acid oxidation disorders with maternal liver diseases in pregnancy.
Collapse
Affiliation(s)
- Prem Shekhawat
- Departments of Pediatric,Washington University School of Medicine, St Louis, Missouri 63110, USA.
| | | | | | | | | | | |
Collapse
|
37
|
Oey NA, den Boer MEJ, Ruiter JPN, Wanders RJA, Duran M, Waterham HR, Boer K, van der Post JAM, Wijburg FA. High activity of fatty acid oxidation enzymes in human placenta: implications for fetal-maternal disease. J Inherit Metab Dis 2003; 26:385-92. [PMID: 12971426 DOI: 10.1023/a:1025163204165] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
As the human fetus and placenta are considered to be primarily dependent on glucose oxidation for energy metabolism, the cause of the remarkable association between severe maternal pregnancy complications and the carriage of a fetus with an inborn error of mitochondrial long-chain fatty acid oxidation (FAO) has remained obscure. We analysed human term placenta and chorionic villus samples for the activities of a variety of enzymes involved in FAO, and compared the results with those obtained in human liver. All enzymes were found to be expressed, with a very high activity of two enzymes involved in the metabolism of long-chain fatty acids (CPT2 and VLCAD), whereas the activity of medium-chain acyl-CoA dehydrogenase (MCAD) was found to be low, when compared to liver. These results suggest that fatty acid oxidation may play an important role in energy generation in human placenta, and that a deficiency in the placental oxidation of long-chain FAO may result in placental dysfunction, thus causing gestational complications.
Collapse
Affiliation(s)
- N A Oey
- Department of Paediatrics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Rakheja D, Bennett MJ, Rogers BB. Long-chain L-3-hydroxyacyl-coenzyme a dehydrogenase deficiency: a molecular and biochemical review. J Transl Med 2002; 82:815-24. [PMID: 12118083 DOI: 10.1097/01.lab.0000021175.50201.46] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Since the first report of long-chain L-3-hydroxyacyl-coenzyme A dehydrogenase deficiency a little more than a decade ago, its phenotypic and genotypic heterogeneity in individuals homozygous for the enzyme defect has become more and more evident. Even more interesting is its association with pregnancy-specific disorders, including preeclampsia, HELLP syndrome (hemolysis, elevated liver enzymes, low platelets), hyperemesis gravidarum, acute fatty liver of pregnancy, and maternal floor infarct of the placenta. In this review we discuss the biochemical and molecular basis, clinical features, diagnosis, and management of long-chain L-3-hydroxyacyl-coenzyme A dehydrogenase deficiency.
Collapse
Affiliation(s)
- Dinesh Rakheja
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
| | | | | |
Collapse
|
39
|
Rakheja D, Bennett MJ, Foster BM, Domiati-Saad R, Rogers BB. Evidence for fatty acid oxidation in human placenta, and the relationship of fatty acid oxidation enzyme activities with gestational age. Placenta 2002; 23:447-50. [PMID: 12061861 DOI: 10.1053/plac.2002.0808] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Fetal disorders of mitochondrial fatty acid oxidation have recently been associated with obstetric complications including pre-eclampsia, Hemolysis, Elevated Liver enzymes, Low Platelets (HELLP) syndrome, placental floor infarct, and Acute Fatty Liver of Pregnancy (AFLP). These diseases occur in about a third of the mothers who are heterozygous for a defect in long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) enzyme and who bear a fetus homozygous for the defect. The mechanism of this association is not clearly understood. In this study, we provide evidence that the placenta may be the site of production of toxic intermediates of fatty acid metabolism, which accumulate to cause liver damage in the mother. We show that two critical enzymes of long chain fatty acid metabolism, long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and short chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD), are active in the normal human placenta. There is an inverse correlation between the enzyme activity of both the enzymes and maternal gestational age during the second and third trimesters. We believe that the demonstration of fatty acid oxidation enzyme activity by the placenta is the first step towards assessing a possible role for fetal/placental fatty acid oxidation defects in the pathogenesis of a subset of pregnancy complications.
Collapse
Affiliation(s)
- D Rakheja
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | | | | | | |
Collapse
|
40
|
Rotta LN, Valle SC, Schweigert I, Ricardi LD, Ferronatto ME, da SL, Souza DO, Perry MLS. Utilization of energy nutrients by cerebellar slices. Neurochem Res 2002; 27:201-6. [PMID: 11958517 DOI: 10.1023/a:1014828419900] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We performed an ontogenetic study about the utilization of glycine, glutamine, beta-hydroxybutyrate and glycerol as energy nutrients by rat cerebellum slices. Production of CO2 from glycerol and glutamine increased with the animals' age and glutamine was the most used nutrient for CO2 production. In adult age, glutamine oxidation to CO2 was 15 to 35 times higher than all other nutrients studied. CO2 production from glycine decreased markedly with age and 10 day-old rats showed an oxidation 7.5 times higher than that of adult rats. At fetal age and at 10 postnatal days, glycine oxidation to CO2 was only 2 times lower than glutamine oxidation to CO2. Lipid synthesis from beta-hydroxybutyrate was highest in adult rats. We did not observe any difference in the utilization of beta-hydroxybutyrate between slices of cerebral cortex and cerebellum at the ages of 10 days and adult. The main nutrients used for lipid synthesis were glycerol and beta-hydroxybutyrate.
Collapse
Affiliation(s)
- Liane N Rotta
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul-Porto Alegre, RS, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Regulation of Ketogenesis in Liver. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
42
|
Sleboda J, Bremer J, Horn RS. Palmitate oxidation in rat hepatocytes is inhibited by foetal calf serum. ACTA PHYSIOLOGICA SCANDINAVICA 2001; 173:267-74. [PMID: 11736689 DOI: 10.1046/j.1365-201x.2001.00896.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The rate of oxidation of fatty acids in mammals is minimal prior to birth. In this study, we have shown that foetal calf serum (FCS) inhibits oxidation of palmitate while serum from newborn calves is almost without effect. Foetal calf serum was also found to increase fatty acid synthesis from acetate. Uptake of laurate in mitochondria is partially dependent upon the carnitine palmitoyltransferase (CPT) I/CPT II system, while octanoate transport occurs without its participation. Comparison of the effects of FCS on the oxidation of palmitate, laurate and octanoate supports the view that the observed actions of FCS result from regulation of CPT I activity. The material in FCS that affects fatty acid metabolism has a molecular weight <3 kDa, as determined by dialysis and ultra-filtration studies.
Collapse
Affiliation(s)
- J Sleboda
- Institute of Medical Biochemistry, University of Oslo, Oslo, Norway
| | | | | |
Collapse
|
43
|
Effect of dietary fish oil on the sensitivity of hepatic lipid metabolism to regulation by insulin. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32380-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
44
|
Abdel-Aleem S, St Louis JD, Hughes GC, Lowe JE. Metabolic changes in the normal and hypoxic neonatal myocardium. Ann N Y Acad Sci 1999; 874:254-61. [PMID: 10415536 DOI: 10.1111/j.1749-6632.1999.tb09240.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hypoxia is characterized by inadequate oxygen delivery to the myocardium with a resulting imbalance between oxygen demand and energy supply. Several adaptive mechanisms occur to preserve myocardial survival during hypoxia. These include both short- and long-term mechanisms, which serve to achieve a new balance between myocardial oxygen demand and energy production. Short-term adaptation includes downregulation of myocardial function along with upregulation of energy production via anaerobic glycolysis following an increase in glucose uptake and glycogen breakdown. Long-term adaptation includes genetic reprogramming of key glycolytic enzymes. Thus, the initial decline in high-energy phosphates following hypoxia is accompanied by a decrease in myocardial contractility and myocardial energy requirements are subsequently met by ATP supplied from anaerobic glycolysis. Thus, a downregulation in cardiac function and/or enhanced energy production via anaerobic glycolysis are the major mechanisms promoting myocardial survival during hypoxia. In contrast to the aforementioned metabolic changes occurring in adult myocardium, the effects of chronic hypoxia on neonatal myocardial metabolism remain undefined. Studies from our laboratory using a novel neonatal piglet model of chronic hypoxia have shown a shift in cardiac myocyte substrate utilization towards the newborn state with a preference for glucose utilization. We have also shown, using this same model, that chronically hypoxic neonatal hearts were more tolerant to ischemia than non-hypoxic hearts. This ischemic tolerance is likely due to adaptive metabolic changes in the chronically hypoxic hearts, such as increased anaerobic glycolysis and glycogen breakdown.
Collapse
Affiliation(s)
- S Abdel-Aleem
- Division of Thoracic Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | | | | | |
Collapse
|
45
|
Sleboda J, Risan KA, Spydevold O, Bremer J. Short-term regulation of carnitine palmitoyltransferase I in cultured rat hepatocytes: spontaneous inactivation and reactivation by fatty acids. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1436:541-9. [PMID: 9989283 DOI: 10.1016/s0005-2760(98)00164-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Liver carnitine palmitoyltransferase I (CPT I), the rate-limiting enzyme of mitochondrial beta-oxidation, rapidly loses its activity when hepatocytes are put in culture. 3-Thia fatty acids reactivate the enzyme and can increase its activity 3-4-fold in 5-10 min. Normal fatty acids are also able to stimulate CPT I, but to a limited extent, compared to 3-thia fatty acid. This activation does not affect malonyl-CoA sensitivity. CPT I in hepatocytes from both fasted and fasted-carbohydrate refed rats is inactivated and reactivated to a similar extent. Free dodecylthioacetic acid (DTA) is at least as efficient as DTA-CoA as activator. CPT I activity in isolated mitochondria is not influenced by incubation with DTA, suggesting that the regulation of CPT I depends on an extramitochondrial component(s) in the cell. It is concluded that fatty acids activate pre-existing, inactive CPT I without involvement of gene transcription and independently of malonyl-CoA.
Collapse
Affiliation(s)
- J Sleboda
- Institute of Medical Biochemistry, University of Oslo, Norway.
| | | | | | | |
Collapse
|
46
|
Abdel-aleem S, St Louis J, Hendrickson SC, El-Shewy HM, El-Dawy K, Taylor DA, Lowe JE. Regulation of carbohydrate and fatty acid utilization by L-carnitine during cardiac development and hypoxia. Mol Cell Biochem 1998; 180:95-103. [PMID: 9546635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study is designed to investigate whether substrate preference in the myocardium during the neonatal period and hypoxia-induced stress is controlled intracellularly or by extracellular substrate availability. To determine this, the effect of exogenous L-carnitine on the regulation of carbohydrate and fatty acid metabolism was determined during cardiac stress (hypoxia) and during the postnatal period. The effect of L-carnitine on long chain (palmitate) and medium chain (octonoate) fatty acid oxidation was studied in cardiac myocytes isolated from less than 24 h old (new born; NB), 2 week old (2 week) and hypoxic 4 week old (HY) piglets. Palmitate oxidation was severely decreased in NB cells compared to those from 2 week animals (0.456+/-0.04 vs. 1.207+/-0.52 nmol/mg protein/30 min); surprisingly, cells from even older hypoxic animals appeared shifted toward the new born state (0.695+/-0.038 nmol/mg protein/30 min). Addition of L-carnitine to the incubation medium, which stimulates carnitine palmitoyl-transferase I (CPTI) accelerated palmitate oxidation 3 fold in NB and approximately 2 fold in HY and 2 week cells. In contrast, octanoate oxidation which was greater in new born myocytes than in 2 week cells, was decreased by L-carnitine suggesting a compensatory response. Furthermore, oxidation of carbohydrates (glucose, pyruvate, and lactate) was greatly increased in new born myocytes compared to 2 week and HY cells and was accompanied by a parallel increase in pyruvate dehydrogenase (PDH) activity. The concentration of malonyl-CoA, a potent inhibitor of CPTI was significantly higher in new born heart than at 2 weeks. These metabolic data taken together suggest that intracellular metabolic signals interact to shift from carbohydrate to fatty acid utilization during development of the myocardium. The decreased oxidation of palmitate in NB hearts probably reflects decreased intracellular L-carnitine and increased malonyl-CoA concentrations. Interestingly, these data further suggest that the cells remain compliant so that under stressful conditions, such as hypoxia, they can revert toward the neonatal state of increased glucose utilization.
Collapse
Affiliation(s)
- S Abdel-aleem
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
Long-chain fatty acids are involved in all aspects of cellular structure and function. For controlling amounts of fatty acids, cells are endowed with two acetyl-coenzyme A carboxylase (ACC) systems. ACC-alpha is the rate-limiting enzyme in the biogenesis of long-chain fatty acids, and ACC-beta is believed to control mitochondrial fatty acid oxidation. These two isoforms of ACC control the amount of fatty acids in the cells. Phosphorylation and dephosphorylation of ACC-alpha cause enzyme inactivation and activation, respectively, and serve as the enzyme's short-term regulatory mechanism. Covalently modified enzymes become more sensitive toward cellular metabolites. In addition, many hormones and nutrients affect gene expression. The gene products formed are heterogeneous and tissue specific. The ACC-beta gene is located on human chromosome 12; the cDNA for this gene has just been cloned. The gene for the alpha-isoform is located on human chromosome 17. The catalytic core of the beta-isoform is homologous to that of the alpha-isoform, except for an additional peptide of about 150 amino acids at the N terminus. This extra peptide sequence makes the beta-form about 10,000 daltons larger, and it is thought to be involved in the unique role that has been assigned to this enzyme. The detailed control mechanisms for the beta-isoform are not known.
Collapse
Affiliation(s)
- K H Kim
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| |
Collapse
|
48
|
Affiliation(s)
- V A Zammit
- Hannah Research Institute, Ayr, Scotland, U.K
| |
Collapse
|
49
|
Chatelain F, Kohl C, Esser V, McGarry JD, Girard J, Pegorier JP. Cyclic AMP and fatty acids increase carnitine palmitoyltransferase I gene transcription in cultured fetal rat hepatocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 235:789-98. [PMID: 8654430 DOI: 10.1111/j.1432-1033.1996.00789.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In the rat, the gene for liver mitochondrial carnitine palmitoyltransferase I (CPT I), though dormant prior to birth, is rapidly activated postnatally. We sought to elucidate which hormonal and/or nutritional factors might be responsible for this induction. In cultured hepatocytes from 20-day-old rat fetus, the concentration of CPT I mRNA, which initially was very low, increased dramatically in a dose-dependent manner after exposure of the cells to dibutyryl cAMP (Bt2cAMP). Similar results were obtained when long-chain fatty acids (LCFA), but not medium-chain fatty acids, were added to the culture medium. The effects of Bt2cAMP and LCFA were antagonized by insulin, also dose dependently. In contrast, CPT II gene expression, which was already high in fetal hepatocytes, was unaffected by any of the above manipulations. Bt2cAMP stimulated CPT I gene expression even when endogenous triacylglycerol breakdown was suppressed by lysosomotropic agents suggesting that the actions of cAMP and LCFA were distinct. Moreover, half-maximal concentrations of Bt2cAMP and linoleate produced an additive effect CPT I mRNA accumulation. While linoleate and Bt2cAMP stimulated CPT I gene transcription by twofold and fourfold, respectively, the fatty acid also increased the half-life of CPT I mRNA (50%). When hepatocytes were cultured in the presence of 2-bromopalmitate, (which is readily converted by cells into its non-metabolizable CoA ester) CPT I mRNA accumulation was higher than that observed with oleate or linoleate. Similarly, the CPT I inhibitor, tetradecylglycidate, which at a concentration of 20 microM did not itself influence the CPT I mRNA level, enhanced the stimulatory effect of linoleate. The implication is that induction of the CPT I message by LCFA does not require mitochondrial metabolism of these substrates; however, formation of their CoA esters is a necessary step. Unlike linoleate, the peroxisome proliferator, clofibrate, increased both CPT I and CPT II mRNA levels and neither effect was offset by insulin. It thus appears that the mechanism of action of LCFA differs from that utilized by clofibrate, which presumably works through the peroxisome proliferator activated receptor. We conclude that the rapid increase in hepatic CPT I mRNA level that accompanies the fetal to neonatal transition in the rat is triggered by the reciprocal change in circulating insulin and LCFA concentrations, coupled with elevation of the liver content of cAMP.
Collapse
Affiliation(s)
- F Chatelain
- Centre de Recherche sur 1'Endocrinologie Moléculaire et le Développement, CNRS, Meudon, France
| | | | | | | | | | | |
Collapse
|
50
|
Park EA, Mynatt RL, Cook GA, Kashfi K. Insulin regulates enzyme activity, malonyl-CoA sensitivity and mRNA abundance of hepatic carnitine palmitoyltransferase-I. Biochem J 1995; 310 ( Pt 3):853-8. [PMID: 7575418 PMCID: PMC1135974 DOI: 10.1042/bj3100853] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The regulation of hepatic mitochondrial carnitine palmitoyltransferase-I (CPT-I) was studied in rats during starvation and insulin-dependent diabetes and in rat H4IIE cells. The Vmax. for CPT-I in hepatic mitochondrial outer membranes isolated from starved and diabetic rats increased 2- and 3-fold respectively over fed control values with no change in Km values for substrates. Regulation of malonyl-CoA sensitivity of CPT-I in isolated mitochondrial outer membranes was indicated by an 8-fold increase in Ki during starvation and by a 50-fold increase in Ki in the diabetic state. Peroxisomal and microsomal CPT also had decreased sensitivity to inhibition by malonyl-CoA during starvation. CPT-I mRNA abundance was 7.5 times greater in livers of 48-h-starved rats and 14.6 times greater in livers of insulin-dependent diabetic rats compared with livers of fed rats. In H4IIE cells, insulin increased CPT-I sensitivity to inhibition by malonyl-CoA in 4 h, and sensitivity continued to increase up to 24 h after insulin addition. CPT-I mRNA levels in H4IIE cells were decreased by insulin after 4 h and continued to decrease so that at 24 h there was a 10-fold difference. The half-life of CPT-I mRNA was 4 h in the presence of actinomycin D or with actinomycin D plus insulin. These results suggest that insulin regulates CPT-I by inhibiting transcription of the CPT-I gene.
Collapse
Affiliation(s)
- E A Park
- Department of Pharmacology, College of Medicine, University of Tennessee, Memphis-The Health Science Center 38163, USA
| | | | | | | |
Collapse
|