1
|
Kim DY, Simeone KA, Simeone TA, Pandya JD, Wilke JC, Ahn Y, Geddes JW, Sullivan PG, Rho JM. Ketone bodies mediate antiseizure effects through mitochondrial permeability transition. Ann Neurol 2015; 78:77-87. [PMID: 25899847 DOI: 10.1002/ana.24424] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 04/03/2015] [Accepted: 04/03/2015] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Ketone bodies (KB) are products of fatty acid oxidation and serve as essential fuels during fasting or treatment with the high-fat antiseizure ketogenic diet (KD). Despite growing evidence that KB exert broad neuroprotective effects, their role in seizure control has not been firmly demonstrated. The major goal of this study was to demonstrate the direct antiseizure effects of KB and to identify an underlying target mechanism. METHODS We studied the effects of both the KD and KB in spontaneously epileptic Kcna1-null mice using a combination of behavioral, planar multielectrode, and standard cellular electrophysiological techniques. Thresholds for mitochondrial permeability transition (mPT) were determined in acutely isolated brain mitochondria. RESULTS KB alone were sufficient to: (1) exert antiseizure effects in Kcna1-null mice, (2) restore intrinsic impairment of hippocampal long-term potentiation and spatial learning-memory defects in Kcna1-null mutants, and (3) raise the threshold for calcium-induced mPT in acutely prepared mitochondria from hippocampi of Kcna1-null animals. Targeted deletion of the cyclophilin D subunit of the mPT complex abrogated the effects of KB on mPT, and in vivo pharmacological inhibition and activation of mPT were found to mirror and reverse, respectively, the antiseizure effects of the KD in Kcna1-null mice. INTERPRETATION The present data reveal the first direct link between mPT and seizure control, and provide a potential mechanistic explanation for the KD. Given that mPT is increasingly being implicated in diverse neurological disorders, our results suggest that metabolism-based treatments and/or metabolic substrates might represent a worthy paradigm for therapeutic development.
Collapse
Affiliation(s)
- Do Young Kim
- Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ
| | - Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE
| | - Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE
| | - Jignesh D Pandya
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY
| | - Julianne C Wilke
- Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ
| | - Younghee Ahn
- Departments of Pediatrics and Clinical Neurosciences, Alberta Children's Hospital Research Institute for Child and Maternal Health, University of Calgary Faculty of Medicine, Calgary, Alberta, Canada
| | - James W Geddes
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY
| | - Jong M Rho
- Departments of Pediatrics and Clinical Neurosciences, Alberta Children's Hospital Research Institute for Child and Maternal Health, University of Calgary Faculty of Medicine, Calgary, Alberta, Canada
| |
Collapse
|
2
|
Puisac B, Arnedo M, Casale CH, Ribate MP, Castiella T, Ramos FJ, Ribes A, Pérez-Cerdá C, Casals N, Hegardt FG, Pié J. Differential HMG-CoA lyase expression in human tissues provides clues about 3-hydroxy-3-methylglutaric aciduria. J Inherit Metab Dis 2010; 33:405-10. [PMID: 20532825 PMCID: PMC2903694 DOI: 10.1007/s10545-010-9097-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 03/30/2010] [Accepted: 04/01/2010] [Indexed: 12/31/2022]
Abstract
3-Hydroxy-3-methylglutaric aciduria is a rare human autosomal recessive disorder caused by deficiency of 3-hydroxy-3-methylglutaryl CoA lyase (HL). This mitochondrial enzyme catalyzes the common final step of leucine degradation and ketogenesis. Acute symptoms include vomiting, seizures and lethargy, accompanied by metabolic acidosis and hypoketotic hypoglycaemia. Such organs as the liver, brain, pancreas, and heart can also be involved. However, the pathophysiology of this disease is only partially understood. We measured mRNA levels, protein expression and enzyme activity of human HMG-CoA lyase from liver, kidney, pancreas, testis, heart, skeletal muscle, and brain. Surprisingly, the pancreas is, after the liver, the tissue with most HL activity. However, in heart and adult brain, HL activity was not detected in the mitochondrial fraction. These findings contribute to our understanding of the enzyme function and the consequences of its deficiency and suggest the need for assessment of pancreatic damage in these patients.
Collapse
Affiliation(s)
- Beatriz Puisac
- Laboratory of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/ Domingo Miral s/n, 50009 Zaragoza, Spain
| | - María Arnedo
- Laboratory of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/ Domingo Miral s/n, 50009 Zaragoza, Spain
| | - Cesar H. Casale
- Department of Molecular Biology, National University of Rio Cuarto, 5800 Rio Cuarto, Cordoba Argentina
| | - María Pilar Ribate
- Laboratory of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/ Domingo Miral s/n, 50009 Zaragoza, Spain
| | - Tomás Castiella
- Department of Pathology, School of Medicine, University of Zaragoza, 50009 Zaragoza, Spain
| | - Feliciano J. Ramos
- Laboratory of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/ Domingo Miral s/n, 50009 Zaragoza, Spain
| | - Antonia Ribes
- Division of Inborn Errors of Metabolism (IBC), Department of Biochemistry and Molecular Genetics, Hospital Clinic and CIBERER, 08036 Barcelona, Spain
| | - Celia Pérez-Cerdá
- Department of Molecular Biology, Molecular Biological Center Severo Ochoa CSIC-UAM, University Autonoma of Madrid, CIBERER, 28049 Madrid, Spain
| | - Nuria Casals
- Department of Biochemistry and Molecular Biology, School of Health Sciences, International University of Catalonia, 08190 Sant Cugat, Barcelona Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de la Salud Carlos III, 28029 Madrid, Spain
| | - Fausto G. Hegardt
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, 08028 Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de la Salud Carlos III, 28029 Madrid, Spain
| | - Juan Pié
- Laboratory of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/ Domingo Miral s/n, 50009 Zaragoza, Spain
| |
Collapse
|
3
|
Takehiro M, Fujimoto S, Shimodahira M, Shimono D, Mukai E, Nabe K, Radu RG, Kominato R, Aramaki Y, Seino Y, Yamada Y. Chronic exposure to beta-hydroxybutyrate inhibits glucose-induced insulin release from pancreatic islets by decreasing NADH contents. Am J Physiol Endocrinol Metab 2005; 288:E372-80. [PMID: 15479955 DOI: 10.1152/ajpendo.00157.2004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate the effects of chronic exposure to ketone bodies on glucose-induced insulin secretion, we evaluated insulin release, intracellular Ca2+ and metabolism, and Ca2+ efficacy of the exocytotic system in rat pancreatic islets. Fifteen-hour exposure to 5 mM d-beta-hydroxybutyrate (HB) reduced high glucose-induced insulin secretion and augmented basal insulin secretion. Augmentation of basal release was derived from promoting the Ca2+-independent and ATP-independent component of insulin release, which was suppressed by the GDP analog. Chronic exposure to HB affected mostly the second phase of glucose-induced biphasic secretion. Dynamic experiments showed that insulin release and NAD(P)H fluorescence were lower, although the intracellular Ca2+ concentration ([Ca2+](i)) was not affected 10 min after exposure to high glucose. Additionally, [Ca2+](i) efficacy in exocytotic system at clamped concentrations of ATP was not affected. NADH content, ATP content, and ATP-to-ADP ratio in the HB-cultured islets in the presence of high glucose were lower, whereas glucose utilization and oxidation were not affected. Mitochondrial ATP production shows that the respiratory chain downstream of complex II is not affected by chronic exposure to HB, and that the decrease in ATP production is due to decreased NADH content in the mitochondrial matrix. Chronic exposure to HB suppresses glucose-induced insulin secretion by lowering the ATP level, at least partly by inhibiting ATP production by reducing the supply of NADH to the respiratory chain. Glucose-induced insulin release in the presence of aminooxyacetate was not reduced, which implies that chronic exposure to HB affects the malate/aspartate shuttle and thus reduces NADH supply to mitochondria.
Collapse
Affiliation(s)
- Mihoko Takehiro
- Dept. of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Abstract
Nutrient secretagogues can increase the production of succinyl-CoA in rat pancreatic islets. When succinate esters are the secretagogue, succinyl-CoA can be generated via the succinate thiokinase reaction. Other secretagogues can increase production of succinyl-CoA secondary to increasing alpha-ketoglutarate production by glutamate dehydrogenase or mitochondrial aspartate aminotransferase followed by the alpha-ketoglutarate dehydrogenase reaction. Although secretagogues can increase the production of succinyl-CoA, they do not increase the level of this metabolite until after they decrease the level of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). This suggests that the generated succinyl-CoA initially reacts with acetoacetate to yield acetoacetyl-CoA plus succinate in the succinyl-CoA-acetoacetate transferase reaction. This would be followed by acetoacetyl-CoA reacting with acetyl-CoA to generate HMG-CoA in the HMG-CoA synthetase reaction. HMG-CoA will then be reduced by NADPH to mevalonate in the HMG-CoA reductase reaction and/or cleaved to acetoacetate plus acetyl-CoA by HMG cleavage enzyme. Succinate derived from either exogenous succinate esters or generated by succinyl-CoA-acetoacetate transferase is metabolized to malate followed by the malic enzyme reaction. Increased production of NADPH by the latter reaction then increases reduction of HMG-CoA and accounts for the decrease in the level of HMG-CoA produced by secretagogues. Pyruvate carboxylation catalyzed by pyruvate carboxylase will supply oxaloacetate to mitochondrial aspartate aminotransferase. This would enable this aminotransferase to supply alpha-ketoglutarate to the alpha-ketoglutarate dehydrogenase complex and would, in part, account for secretagogues increasing the islet level of succinyl-CoA after they decrease the level of HMG-CoA. Mevalonate could be a trigger of insulin release as a result of its ability to alter membrane proteins and/or cytosolic Ca(2+). This is consistent with the fact that insulin secretagogues decrease the level of the mevalonate precursor HMG-CoA. In addition, inhibitors of HMG-CoA reductase interfere with insulin release and this inhibition can be reversed by mevalonate.
Collapse
Affiliation(s)
- Leonard A Fahien
- Department of Pharmacology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
| | | |
Collapse
|
6
|
Malaisse WJ, Sener A. Hexose metabolism in pancreatic islets. Activation of the Krebs cycle by nutrient secretagogues. Mol Cell Biochem 1991; 107:95-102. [PMID: 1791828 DOI: 10.1007/bf00225512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In rat pancreatic islets, a rise in extracellular D-glucose concentration is known to cause a greater increase in the oxidation of D-[6-14C]glucose than utilization of D-[5-3H]glucose. In the present study, such a preferential stimulation of acetyl residue oxidation relative to glycolytic flux was mimicked by nutrient secretagogues such as 2-aminobicyclo[2,2,1]heptane-2-carboxylate, 3-phenylpyruvate, L-leucine, 2-ketoisocaproate, D-fructose and ketone bodies. The preferential stimulation of D-[6-14C]glucose oxidation by these nutrients was observed at all hexose concentrations (0.5, 6.0 and 16.7 mM), coincided with an unaltered rate of D-[3,4-14C]glucose oxidation, was impaired in the absence of extracellular Ca2+, and failed to be affected by NH4+. Although the ratio between D-[6-14C]glucose oxidation and D-[5-3H]glucose utilization in islets exposed to other nutrient secretagogues could be affected by factors such as isotopic dilution and mitochondrial redox state, the present data afford strong support to the view that the preferential stimulation of oxidative events in the Krebs cycle of nutrient-stimulated islets is linked to the activation of key mitochondrial dehydrogenases, e.g. 2-ketoglutarate dehydrogenase. The latter activation might result from the mitochondrial accumulation of Ca2+, as attributable not solely to stimulation of Ca2+ inflow into the islet cells but also to an increase in ATP availability.
Collapse
Affiliation(s)
- W J Malaisse
- Laboratory of Experimental Medicine, Brussels Free University, Belgium
| | | |
Collapse
|