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van Eunen K, Volker-Touw CML, Gerding A, Bleeker A, Wolters JC, van Rijt WJ, Martines ACMF, Niezen-Koning KE, Heiner RM, Permentier H, Groen AK, Reijngoud DJ, Derks TGJ, Bakker BM. Living on the edge: substrate competition explains loss of robustness in mitochondrial fatty-acid oxidation disorders. BMC Biol 2016; 14:107. [PMID: 27927213 PMCID: PMC5142382 DOI: 10.1186/s12915-016-0327-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/11/2016] [Indexed: 12/02/2022] Open
Abstract
Background Defects in genes involved in mitochondrial fatty-acid oxidation (mFAO) reduce the ability of patients to cope with metabolic challenges. mFAO enzymes accept multiple substrates of different chain length, leading to molecular competition among the substrates. Here, we combined computational modeling with quantitative mouse and patient data to investigate whether substrate competition affects pathway robustness in mFAO disorders. Results First, we used comprehensive biochemical analyses of wild-type mice and mice deficient for medium-chain acyl-CoA dehydrogenase (MCAD) to parameterize a detailed computational model of mFAO. Model simulations predicted that MCAD deficiency would have no effect on the pathway flux at low concentrations of the mFAO substrate palmitoyl-CoA. However, high concentrations of palmitoyl-CoA would induce a decline in flux and an accumulation of intermediate metabolites. We proved computationally that the predicted overload behavior was due to substrate competition in the pathway. Second, to study the clinical relevance of this mechanism, we used patients’ metabolite profiles and generated a humanized version of the computational model. While molecular competition did not affect the plasma metabolite profiles during MCAD deficiency, it was a key factor in explaining the characteristic acylcarnitine profiles of multiple acyl-CoA dehydrogenase deficient patients. The patient-specific computational models allowed us to predict the severity of the disease phenotype, providing a proof of principle for the systems medicine approach. Conclusion We conclude that substrate competition is at the basis of the physiology seen in patients with mFAO disorders, a finding that may explain why these patients run a risk of a life-threatening metabolic catastrophe. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0327-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karen van Eunen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Top Institute for Food and Nutrition, Nieuwe Kanaal 9A, 7609 PA, Wageningen, The Netherlands
| | - Catharina M L Volker-Touw
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Present address: Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Albert Gerding
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Aycha Bleeker
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Top Institute for Food and Nutrition, Nieuwe Kanaal 9A, 7609 PA, Wageningen, The Netherlands
| | - Justina C Wolters
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Analytical Biochemistry and Interfaculty Mass Spectrometry Center, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Willemijn J van Rijt
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Anne-Claire M F Martines
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Klary E Niezen-Koning
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Rebecca M Heiner
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Hjalmar Permentier
- Analytical Biochemistry and Interfaculty Mass Spectrometry Center, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Albert K Groen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Top Institute for Food and Nutrition, Nieuwe Kanaal 9A, 7609 PA, Wageningen, The Netherlands.,Systems Biology Center for Energy Metabolism and Aging, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Dirk-Jan Reijngoud
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.,Systems Biology Center for Energy Metabolism and Aging, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Terry G J Derks
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Barbara M Bakker
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands. .,Systems Biology Center for Energy Metabolism and Aging, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands. .,, PO Box 196, Internal ZIP code EA12, NL-9700 AD, Groningen, The Netherlands.
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Subramanian C, Yun MK, Yao J, Sharma LK, Lee RE, White SW, Jackowski S, Rock CO. Allosteric Regulation of Mammalian Pantothenate Kinase. J Biol Chem 2016; 291:22302-22314. [PMID: 27555321 DOI: 10.1074/jbc.m116.748061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Indexed: 12/21/2022] Open
Abstract
Pantothenate kinase is the master regulator of CoA biosynthesis and is feedback-inhibited by acetyl-CoA. Comparison of the human PANK3·acetyl-CoA complex to the structures of PANK3 in four catalytically relevant complexes, 5'-adenylyl-β,γ-imidodiphosphate (AMPPNP)·Mg2+, AMPPNP·Mg2+·pantothenate, ADP·Mg2+·phosphopantothenate, and AMP phosphoramidate (AMPPN)·Mg2+, revealed a large conformational change in the dimeric enzyme. The amino-terminal nucleotide binding domain rotates to close the active site, and this allows the P-loop to engage ATP and facilitates required substrate/product interactions at the active site. Biochemical analyses showed that the transition between the inactive and active conformations, as assessed by the binding of either ATP·Mg2+ or acyl-CoA to PANK3, is highly cooperative indicating that both protomers move in concert. PANK3(G19V) cannot bind ATP, and biochemical analyses of an engineered PANK3/PANK3(G19V) heterodimer confirmed that the two active sites are functionally coupled. The communication between the two protomers is mediated by an α-helix that interacts with the ATP-binding site at its amino terminus and with the substrate/inhibitor-binding site of the opposite protomer at its carboxyl terminus. The two α-helices within the dimer together with the bound ligands create a ring that stabilizes the assembly in either the active closed conformation or the inactive open conformation. Thus, both active sites of the dimeric mammalian pantothenate kinases coordinately switch between the on and off states in response to intracellular concentrations of ATP and its key negative regulators, acetyl(acyl)-CoA.
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Affiliation(s)
| | | | | | - Lalit Kumar Sharma
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Richard E Lee
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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53
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Machado MV, Kruger L, Jewell ML, Michelotti GA, Pereira TDA, Xie G, Moylan CA, Diehl AM. Vitamin B5 and N-Acetylcysteine in Nonalcoholic Steatohepatitis: A Preclinical Study in a Dietary Mouse Model. Dig Dis Sci 2016; 61:137-48. [PMID: 26403427 PMCID: PMC4703517 DOI: 10.1007/s10620-015-3871-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/03/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease and second indication for liver transplantation in the Western world. Effective therapy is still not available. Previously we showed a critical role for caspase-2 in the pathogenesis of nonalcoholic steatohepatitis (NASH), the potentially progressive form of NAFLD. An imbalance between free coenzyme A (CoA) and acyl-CoA ratio is known to induce caspase-2 activation. OBJECTIVES We aimed to evaluate CoA metabolism and the effects of supplementation with CoA precursors, pantothenate and cysteine, in mouse models of NASH. METHODS CoA metabolism was evaluated in methionine-choline deficient (MCD) and Western diet mouse models of NASH. MCD diet-fed mice were treated with pantothenate and N-acetylcysteine or placebo to determine effects on NASH. RESULTS Liver free CoA content was reduced, pantothenate kinase (PANK), the rate-limiting enzyme in the CoA biosynthesis pathway, was down-regulated, and CoA degrading enzymes were increased in mice with NASH. Decreased hepatic free CoA content was associated with increased caspase-2 activity and correlated with worse liver cell apoptosis, inflammation, and fibrosis. Treatment with pantothenate and N-acetylcysteine did not inhibit caspase-2 activation, improve NASH, normalize PANK expression, or restore free CoA levels in MCD diet-fed mice. CONCLUSION In mice with NASH, hepatic CoA metabolism is impaired, leading to decreased free CoA content, activation of caspase-2, and increased liver cell apoptosis. Dietary supplementation with CoA precursors did not restore CoA levels or improve NASH, suggesting that alternative approaches are necessary to normalize free CoA during NASH.
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Affiliation(s)
- Mariana Verdelho Machado
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
- Gastroenterology Department, Hospital de Santa Maria, CHLN, Lisbon, Portugal
| | - Leandi Kruger
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Mark L Jewell
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Gregory Alexander Michelotti
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Thiago de Almeida Pereira
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Guanhua Xie
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Cynthia A Moylan
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA
| | - Anna Mae Diehl
- Division of Gastroenterology, Department of Medicine, Duke University Medical Center, 905 LaSalle Street, Snyderman Building, Suite 1073, Durham, NC, 27710, USA.
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54
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Zano SP, Pate C, Frank M, Rock CO, Jackowski S. Correction of a genetic deficiency in pantothenate kinase 1 using phosphopantothenate replacement therapy. Mol Genet Metab 2015; 116:281-8. [PMID: 26549575 PMCID: PMC4764103 DOI: 10.1016/j.ymgme.2015.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 10/27/2015] [Indexed: 02/03/2023]
Abstract
Coenzyme A (CoA) is a ubiquitous cofactor involved in numerous essential biochemical transformations, and along with its thioesters is a key regulator of intermediary metabolism. Pantothenate (vitamin B5) phosphorylation by pantothenate kinase (PanK) is thought to control the rate of CoA production. Pantothenate kinase associated neurodegeneration is a hereditary disease that arises from mutations that inactivate the human PANK2 gene. Aryl phosphoramidate phosphopantothenate derivatives were prepared to test the feasibility of using phosphopantothenate replacement therapy to bypass the genetic deficiency in the Pank1(-/-) mouse model. The efficacies of candidate compounds were first compared by measuring the ability to increase CoA levels in Pank1(-/-) mouse embryo fibroblasts. Administration of selected candidate compounds to Pank1(-/-) mice corrected their deficiency in hepatic CoA. The PanK bypass was confirmed by the incorporation of intact phosphopantothenate into CoA using triple-isotopically labeled compound. These results provide strong support for PanK as a master regulator of intracellular CoA and illustrate the feasibility of employing PanK bypass therapy to restore CoA levels in genetically deficient mice.
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Affiliation(s)
- Stephen P Zano
- St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Caroline Pate
- St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Matthew Frank
- St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Charles O Rock
- St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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55
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Extracellular 4'-phosphopantetheine is a source for intracellular coenzyme A synthesis. Nat Chem Biol 2015; 11:784-92. [PMID: 26322826 DOI: 10.1038/nchembio.1906] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/03/2015] [Indexed: 12/20/2022]
Abstract
The metabolic cofactor coenzyme A (CoA) gained renewed attention because of its roles in neurodegeneration, protein acetylation, autophagy and signal transduction. The long-standing dogma is that eukaryotic cells obtain CoA exclusively via the uptake of extracellular precursors, especially vitamin B5, which is intracellularly converted through five conserved enzymatic reactions into CoA. This study demonstrates an alternative mechanism that allows cells and organisms to adjust intracellular CoA levels by using exogenous CoA. Here CoA was hydrolyzed extracellularly by ectonucleotide pyrophosphatases to 4'-phosphopantetheine, a biologically stable molecule able to translocate through membranes via passive diffusion. Inside the cell, 4'-phosphopantetheine was enzymatically converted back to CoA by the bifunctional enzyme CoA synthase. Phenotypes induced by intracellular CoA deprivation were reversed when exogenous CoA was provided. Our findings answer long-standing questions in fundamental cell biology and have major implications for the understanding of CoA-related diseases and therapies.
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56
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Shumar SA, Fagone P, Alfonso-Pecchio A, Gray JT, Rehg JE, Jackowski S, Leonardi R. Induction of Neuron-Specific Degradation of Coenzyme A Models Pantothenate Kinase-Associated Neurodegeneration by Reducing Motor Coordination in Mice. PLoS One 2015; 10:e0130013. [PMID: 26052948 PMCID: PMC4460045 DOI: 10.1371/journal.pone.0130013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/15/2015] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Pantothenate kinase-associated neurodegeneration, PKAN, is an inherited disorder characterized by progressive impairment in motor coordination and caused by mutations in PANK2, a human gene that encodes one of four pantothenate kinase (PanK) isoforms. PanK initiates the synthesis of coenzyme A (CoA), an essential cofactor that plays a key role in energy metabolism and lipid synthesis. Most of the mutations in PANK2 reduce or abolish the activity of the enzyme. This evidence has led to the hypothesis that lower CoA might be the underlying cause of the neurodegeneration in PKAN patients; however, no mouse model of the disease is currently available to investigate the connection between neuronal CoA levels and neurodegeneration. Indeed, genetic and/or dietary manipulations aimed at reducing whole-body CoA synthesis have not produced a desirable PKAN model, and this has greatly hindered the discovery of a treatment for the disease. OBJECTIVE, METHODS, RESULTS AND CONCLUSIONS Cellular CoA levels are tightly regulated by a balance between synthesis and degradation. CoA degradation is catalyzed by two peroxisomal nudix hydrolases, Nudt7 and Nudt19. In this study we sought to reduce neuronal CoA in mice through the alternative approach of increasing Nudt7-mediated CoA degradation. This was achieved by combining the use of an adeno-associated virus-based expression system with the synapsin (Syn) promoter. We show that mice with neuronal overexpression of a cytosolic version of Nudt7 (scAAV9-Syn-Nudt7cyt) exhibit a significant decrease in brain CoA levels in conjunction with a reduction in motor coordination. These results strongly support the existence of a link between CoA levels and neuronal function and show that scAAV9-Syn-Nudt7cyt mice can be used to model PKAN.
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Affiliation(s)
- Stephanie A. Shumar
- Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Paolo Fagone
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Adolfo Alfonso-Pecchio
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - John T. Gray
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Suzanne Jackowski
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Roberta Leonardi
- Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, West Virginia, United States of America
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57
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Deregulated coenzyme A, loss of metabolic flexibility and diabetes. Biochem Soc Trans 2015; 42:1118-22. [PMID: 25110012 DOI: 10.1042/bst20140156] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
CoA (coenzyme A) is an essential cofactor that is emerging as a global regulator of energy metabolism. Tissue CoA levels are tightly regulated and vary in response to different conditions including nutritional state and diabetes. Recent studies reveal the ability of this cofactor to control the output of key metabolic pathways. CoA regulation is important for the maintenance of metabolic flexibility and glucose homoeostasis.
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58
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Methods for measuring CoA and CoA derivatives in biological samples. Biochem Soc Trans 2015; 42:1107-11. [PMID: 25110010 DOI: 10.1042/bst20140123] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CoA (coenzyme A) is a ubiquitous and essential cofactor that acts as an acyl group carrier in biochemical reactions. Apart from participating in numerous metabolic pathways as substrates and intermediates, CoA and a number of its thioester derivatives, such as acetyl-CoA, can also directly regulate the activity of proteins by allosteric mechanisms and by affecting protein acetylation reactions. Cellular levels of CoA and CoA thioesters change under various physiological and pathological conditions. Defective CoA biosynthesis is implicated in NBIA (neurodegeneration with brain iron accumulation). However, the exact role of CoA in the pathogenesis of NBIA is not well understood. Accurate and reliable assays for measuring CoA species in biological samples are essential for studying the roles of CoA and CoA derivatives in health and disease. The present mini-review discusses methods that are commonly used to measure CoA species in biological samples.
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Exploiting the coenzyme A biosynthesis pathway for the identification of new antimalarial agents: the case for pantothenamides. Biochem Soc Trans 2015; 42:1087-93. [PMID: 25110007 DOI: 10.1042/bst20140158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Malaria kills more than half a million people each year. There is no vaccine, and recent reports suggest that resistance is developing to the antimalarial regimes currently recommended by the World Health Organization. New drugs are therefore needed to ensure malaria treatment options continue to be available. The intra-erythrocytic stage of the malaria parasite's life cycle is dependent on an extracellular supply of pantothenate (vitamin B5), the precursor of CoA (coenzyme A). It has been known for many years that proliferation of the parasite during this stage of its life cycle can be inhibited with pantothenate analogues. We have shown recently that pantothenamides, a class of pantothenate analogues with antibacterial activity, inhibit parasite proliferation at submicromolar concentrations and do so competitively with pantothenate. These compounds, however, are degraded, and therefore rendered inactive, by the enzyme pantetheinase (vanin), which is present in serum. In the present mini-review, we discuss the two strategies that have been put forward to overcome pantetheinase-mediated degradation of pantothenamides. The strategies effectively provide an opportunity for pantothenamides to be tested in vivo. We also put forward our 'blueprint' for the further development of pantothenamides (and other pantothenate analogues) as potential antimalarials.
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Abstract
In all organisms biomolecules play a vital role to enable proper cellular metabolism. Alteration of metabolite homoeostasis disrupts the physiology of cells, leading to various diseases [DeBerardinis and Thompson (2012) Cell, 148, 1132-1144]. Recent studies advances our understanding that some metabolites are not only involved in cellular metabolism, but also have other molecular functions. It has become evident that similar to multifunctional 'moonlighting proteins', 'moonlighting metabolites' also exists. One clear example is nicotinamide adenine dinucleotide (NAD). NAD is a ubiquitous molecule with a well-known function in many metabolic reactions, but it also has become clear that NAD is involved in the regulation of sirtuins. Sirtuins play a role in cancer, diabetes, and cardiovascular, neurodegenerative and other diseases [Donmez and Outeiro (2013) EMBO Mol. Med. 5, 344-352] and the deacetylation capacity of sirtuin proteins is NAD-dependent. This direct role of NAD in age-related diseases could not be anticipated when NAD was initially discovered as a metabolic cofactor [Donmez and Outeiro (2013) EMBO Mol. Med. 5, 344-352; Mouchiroud et al. (2013) Crit. Rev. Biochem. Mol. Biol. 48, 397-408]. Recent findings now also indicate that CoA (coenzyme A), another metabolic cofactor, can be considered as being more than 'just' a metabolic cofactor, and altered CoA levels lead to severe and complex effects.
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Meyer E, Kurian MA, Hayflick SJ. Neurodegeneration with Brain Iron Accumulation: Genetic Diversity and Pathophysiological Mechanisms. Annu Rev Genomics Hum Genet 2015; 16:257-79. [PMID: 25973518 DOI: 10.1146/annurev-genom-090314-025011] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurodegeneration with brain iron accumulation (NBIA) comprises a heterogeneous group of progressive disorders with the common feature of excessive iron deposition in the brain. Over the last decade, advances in sequencing technologies have greatly facilitated rapid gene discovery, and several single-gene disorders are now included in this group. Identification of the genetic bases of the NBIA disorders has advanced our understanding of the disease processes caused by reduced coenzyme A synthesis, impaired lipid metabolism, mitochondrial dysfunction, and defective autophagy. The contribution of iron to disease pathophysiology remains uncertain, as does the identity of a putative final common pathway by which the iron accumulates. Ongoing elucidation of the pathogenesis of each NBIA disorder will have significant implications for the identification and design of novel therapies to treat patients with these disorders.
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Affiliation(s)
- Esther Meyer
- Molecular Neurosciences, Developmental Neurosciences Programme, Institute of Child Health, University College London, London WC1N 1EH, United Kingdom; ,
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Abnormal red cell features associated with hereditary neurodegenerative disorders: the neuroacanthocytosis syndromes. Curr Opin Hematol 2015; 21:201-9. [PMID: 24626044 DOI: 10.1097/moh.0000000000000035] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This review discusses the mechanisms involved in the generation of thorny red blood cells (RBCs), known as acanthocytes, in patients with neuroacanthocytosis, a heterogenous group of neurodegenerative hereditary disorders that include chorea-acanthocytosis (ChAc) and McLeod syndrome (MLS). RECENT FINDINGS Although molecular defects associated with neuroacanthocytosis have been identified recently, their pathophysiology and the related RBC abnormalities are largely unknown. Studies in ChAc RBCs have shown an altered association between the cytoskeleton and the integral membrane protein compartment in the absence of major changes in RBC membrane composition. In ChAc RBCs, abnormal Lyn kinase activation in a Syk-independent fashion has been reported recently, resulting in increased band 3 tyrosine phosphorylation and perturbation of the stability of the multiprotein band 3-based complexes bridging the membrane to the spectrin-based membrane skeleton. Similarly, in MLS, the absence of XK-protein, which is associated with the spectrin-actin-4.1 junctional complex, is associated with an abnormal membrane protein phosphorylation state, with destabilization of the membrane skeletal network resulting in generation of acanthocytes. SUMMARY A novel mechanism in generation of acanthocytes involving abnormal Lyn activation, identified in ChAc, expands the acanthocytosis phenomenon toward protein-protein interactions, controlled by phosphorylation-related abnormal signaling.
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de Villiers M, Barnard L, Koekemoer L, Snoep JL, Strauss E. Variation in pantothenate kinase type determines the pantothenamide mode of action and impacts on coenzyme A salvage biosynthesis. FEBS J 2014; 281:4731-53. [PMID: 25156889 DOI: 10.1111/febs.13013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/18/2014] [Accepted: 08/18/2014] [Indexed: 11/28/2022]
Abstract
N-substituted pantothenamides are analogues of pantothenic acid, the vitamin precursor of CoA, and constitute a class of well-studied bacterial growth inhibitors that show potential as new antibacterial agents. Previous studies have highlighted the importance of pantothenate kinase (PanK; EC 2.7.1.33) (the first enzyme of CoA biosynthesis) in mediating pantothenamide-induced growth inhibition by one of two proposed mechanisms: first, by acting on the pantothenamides as alternate substrates (allowing their conversion into CoA antimetabolites, with subsequent effects on CoA- and acyl carrier protein-dependent processes) or, second, by being directly inhibited by them (causing a reduction in CoA biosynthesis). In the present study we used structurally modified pantothenamides to probe whether PanKs interact with these compounds in the same manner. We show that the three distinct types of eubacterial PanKs that are known to exist (PanKI , PanKII and PanKIII ) respond very differently and, consequently, are responsible for determining the pantothenamide mode of action in each case: although the promiscuous PanKI enzymes accept them as substrates, the highly selective PanKIII s are resistant to their inhibitory effects. Most unexpectedly, Staphylococcus aureus PanK (the only known example of a bacterial PanKII ) experiences uncompetitive inhibition in a manner that is described for the first time. In addition, we show that pantetheine, a CoA degradation product that closely resembles the pantothenamides, causes the same effect. This suggests that, in S. aureus, pantothenamides may act by usurping a previously unknown role of pantetheine in the regulation of CoA biosynthesis, and validates its PanK as a target for the development of new antistaphylococcal agents.
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Leonardi R, Rock CO, Jackowski S. Pank1 deletion in leptin-deficient mice reduces hyperglycaemia and hyperinsulinaemia and modifies global metabolism without affecting insulin resistance. Diabetologia 2014; 57:1466-75. [PMID: 24781151 PMCID: PMC4618598 DOI: 10.1007/s00125-014-3245-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 03/28/2014] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Pantothenate kinase (PANK) is the first enzyme in CoA biosynthesis. Pank1-deficient mice have 40% lower liver CoA and fasting hypoglycaemia, which results from reduced gluconeogenesis. Single-nucleotide polymorphisms in the human PANK1 gene are associated with insulin levels, suggesting a link between CoA and insulin homeostasis. We determined whether Pank1 deficiency (1) modified insulin levels, (2) ameliorated hyperglycaemia and hyperinsulinaemia, and (3) improved acute glucose and insulin tolerance of leptin (Lep)-deficient mice. METHODS Serum insulin and responses to glucose and insulin tolerance tests were determined in Pank1-deficient mice. Levels of CoA and regulating enzymes were measured in liver and skeletal muscle of Lep-deficient mice. Double Pank1/Lep-deficient mice were analysed for the diabetes-related phenotype and global metabolism. RESULTS Pank1-deficient mice had lower serum insulin and improved glucose tolerance and insulin sensitivity compared with wild-type mice. Hepatic and muscle CoA was abnormally high in Lep-deficient mice. Pank1 deletion reduced hepatic CoA but not muscle CoA, reduced serum glucose and insulin, but did not normalise body weight or improve acute glucose tolerance or protein kinase B phosphorylation in Lep-deficient animals. Pank1/Lep double-deficient mice exhibited reduced whole-body metabolism of fatty acids and amino acids and had a greater reliance on carbohydrate use for energy production. CONCLUSIONS/INTERPRETATION The results indicate that Pank1 deficiency drives a whole-body metabolic adaptation that improves aspects of the diabetic phenotype and uncouples hyperglycaemia and hyperinsulinaemia from obesity in leptin-deficient mice.
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Affiliation(s)
- Roberta Leonardi
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Charles O. Rock
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Suzanne Jackowski
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- To whom correspondence should be addressed: Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678; Phone: 901-595-3494; Fax: 901-595-3099;
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Badenhorst CPS, Erasmus E, van der Sluis R, Nortje C, van Dijk AA. A new perspective on the importance of glycine conjugation in the metabolism of aromatic acids. Drug Metab Rev 2014; 46:343-61. [PMID: 24754494 DOI: 10.3109/03602532.2014.908903] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A number of endogenous and xenobiotic organic acids are conjugated to glycine, in animals ranging from mosquitoes to humans. Glycine conjugation has generally been assumed to be a detoxification mechanism, increasing the water solubility of organic acids in order to facilitate urinary excretion. However, the recently proposed glycine deportation hypothesis states that the role of the amino acid conjugations, including glycine conjugation, is to regulate systemic levels of amino acids that are also utilized as neurotransmitters in the central nervous systems of animals. This hypothesis is based on the observation that, compared to glucuronidation, glycine conjugation does not significantly increase the water solubility of aromatic acids. In this review it will be argued that the major role of glycine conjugation is to dispose of the end products of phenylpropionate metabolism. Furthermore, glucuronidation, which occurs in the endoplasmic reticulum, would not be ideal for the detoxification of free benzoate, which has been shown to accumulate in the mitochondrial matrix. Glycine conjugation, however, prevents accumulation of benzoic acid in the mitochondrial matrix by forming hippurate, a less lipophilic conjugate that can be more readily transported out of the mitochondria. Finally, it will be explained that the glycine conjugation of benzoate, a commonly used preservative, exacerbates the dietary deficiency of glycine in humans. Because the resulting shortage of glycine can negatively influence brain neurochemistry and the synthesis of collagen, nucleic acids, porphyrins, and other important metabolites, the risks of using benzoate as a preservative should not be underestimated.
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66
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Liu X, Hu Y, Pai PJ, Chen D, Lam H. Label-free quantitative proteomics analysis of antibiotic response in Staphylococcus aureus to oxacillin. J Proteome Res 2014; 13:1223-33. [PMID: 24156611 DOI: 10.1021/pr400669d] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is the leading cause of fatal bacterial infections in hospitals and has become a global health threat. Although the resistance mechanisms of β-lactam antibiotics have been studied for decades, there are few attempts at systems-wide investigations into how the bacteria respond to antibiotic stress. Spectral counting-based label-free quantitative proteomics has been applied to study global responses in MRSA and methicillin-susceptible S. aureus (MSSA) treated with subinhibitory doses of oxacillin, a model β-lactam antibiotic. We developed a simple and easily repeated sample preparation procedure that is effective for extracting surface-associated proteins. On average, 1025 and 1013 proteins were identified at a false discovery rate threshold of 0.01, for the untreated group of MRSA and MSSA. Upon treatment with oxacillin, 81 proteins (65 up-regulated, 16 down-regulated) were shown differentially expressed in MRSA (p < 0.05). In comparison, 225 proteins (162 up-regulated, 63 down-regulated) were shown differentially expressed in oxacillin-treated MSSA. β-Lactamase and penicillin-binding protein 2a were observed up-regulated uniquely in oxacillin-treated MRSA, which is consistent with the known β-lactam resistance mechanisms of S. aureus. More interestingly, the peptidoglycan biosynthesis pathway and the pantothenate and CoA biosynthesis pathway were found to be up-regulated in both oxacillin-treated MRSA and MSSA, and a series of energy metabolism pathways were up-regulated uniquely in oxacillin-treated MSSA. These new data offer a more complete view of the proteome changes in bacteria in response to the antibiotic. This report is the first in using label-free quantitative proteomics to study β-lactam antibiotic responses in S. aureus.
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Affiliation(s)
- Xiaofen Liu
- Department of Chemical and Biomolecular Engineering and ‡Division of Biomedical Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
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67
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Metabolic activation of CaMKII by coenzyme A. Mol Cell 2013; 52:325-39. [PMID: 24095281 DOI: 10.1016/j.molcel.2013.08.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/18/2013] [Accepted: 08/20/2013] [Indexed: 11/21/2022]
Abstract
Active metabolism regulates oocyte cell death via calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated phosphorylation of caspase-2, but the link between metabolic activity and CaMKII is poorly understood. Here we identify coenzyme A (CoA) as the key metabolic signal that inhibits Xenopus laevis oocyte apoptosis by directly activating CaMKII. We found that CoA directly binds to the CaMKII regulatory domain in the absence of Ca(2+) to activate CaMKII in a calmodulin-dependent manner. Furthermore, we show that CoA inhibits apoptosis not only in X. laevis oocytes but also in Murine oocytes. These findings uncover a direct mechanism of CaMKII regulation by metabolism and further highlight the importance of metabolism in preserving oocyte viability.
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68
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A liver-specific defect of Acyl-CoA degradation produces hyperammonemia, hypoglycemia and a distinct hepatic Acyl-CoA pattern. PLoS One 2013; 8:e60581. [PMID: 23861731 PMCID: PMC3702508 DOI: 10.1371/journal.pone.0060581] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/06/2013] [Indexed: 01/15/2023] Open
Abstract
Most conditions detected by expanded newborn screening result from deficiency of one of the enzymes that degrade acyl-coenzyme A (CoA) esters in mitochondria. The role of acyl-CoAs in the pathophysiology of these disorders is poorly understood, in part because CoA esters are intracellular and samples are not generally available from human patients. We created a mouse model of one such condition, deficiency of 3-hydroxy-3-methylglutaryl-CoA lyase (HL), in liver (HLLKO mice). HL catalyses a reaction of ketone body synthesis and of leucine degradation. Chronic HL deficiency and acute crises each produced distinct abnormal liver acyl-CoA patterns, which would not be predictable from levels of urine organic acids and plasma acylcarnitines. In HLLKO hepatocytes, ketogenesis was undetectable. Carboxylation of [2-(14)C] pyruvate diminished following incubation of HLLKO hepatocytes with the leucine metabolite 2-ketoisocaproate (KIC). HLLKO mice also had suppression of the normal hyperglycemic response to a systemic pyruvate load, a measure of gluconeogenesis. Hyperammonemia and hypoglycemia, cardinal features of many inborn errors of acyl-CoA metabolism, occurred spontaneously in some HLLKO mice and were inducible by administering KIC. KIC loading also increased levels of several leucine-related acyl-CoAs and reduced acetyl-CoA levels. Ultrastructurally, hepatocyte mitochondria of KIC-treated HLLKO mice show marked swelling. KIC-induced hyperammonemia improved following administration of carglumate (N-carbamyl-L-glutamic acid), which substitutes for the product of an acetyl-CoA-dependent reaction essential for urea cycle function, demonstrating an acyl-CoA-related mechanism for this complication.
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Abstract
Abnormal accumulation of brain iron has been detected in various neurodegenerative diseases, but the contribution of iron overload to pathology remains unclear. In a group of distinctive brain iron overload diseases known as 'neurodegeneration with brain iron accumulation' (NBIA) diseases, nine disease genes have been identified. Brain iron accumulation is observed in the globus pallidus and other brain regions in NBIA diseases, which are often associated with severe dystonia and gait abnormalities. Only two of these diseases, aceruloplasminaemia and neuroferritinopathy, are directly caused by abnormalities in iron metabolism, mainly in astrocytes and neurons, respectively. Understanding the early molecular pathophysiology of these diseases should aid insights into the role of iron and the design of specific therapeutic approaches.
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70
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Badenhorst CPS, van der Sluis R, Erasmus E, van Dijk AA. Glycine conjugation: importance in metabolism, the role of glycine N-acyltransferase, and factors that influence interindividual variation. Expert Opin Drug Metab Toxicol 2013; 9:1139-53. [PMID: 23650932 DOI: 10.1517/17425255.2013.796929] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Glycine conjugation of mitochondrial acyl-CoAs, catalyzed by glycine N-acyltransferase (GLYAT, E.C. 2.3.1.13), is an important metabolic pathway responsible for maintaining adequate levels of free coenzyme A (CoASH). However, because of the small number of pharmaceutical drugs that are conjugated to glycine, the pathway has not yet been characterized in detail. Here, we review the causes and possible consequences of interindividual variation in the glycine conjugation pathway. AREAS COVERED The authors review the importance of CoASH in metabolism, formation and toxicity of xenobiotic acyl-CoAs, and mechanisms for restoring levels of CoASH. They focus on GLYAT, glycine conjugation, how genetic variation in the GLYAT gene could influence glycine conjugation, and the emerging roles of glycine metabolism in cancer and musculoskeletal development. EXPERT OPINION The substrate selectivity of GLYAT and its variants needs to be further characterized, as organic acids can be toxic if the corresponding acyl-CoA is not a substrate for glycine conjugation. GLYAT activity affects mitochondrial ATP production, glycine availability, CoASH availability, and the toxicity of various organic acids. Therefore, variation in the glycine conjugation pathway could influence liver cancer, musculoskeletal development, and mitochondrial energy metabolism.
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71
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Jensen PD, Zhang Y, Wiggins BE, Petrick JS, Zhu J, Kerstetter RA, Heck GR, Ivashuta SI. Computational sequence analysis of predicted long dsRNA transcriptomes of major crops reveals sequence complementarity with human genes. GM CROPS & FOOD 2013; 4:90-7. [PMID: 23787988 DOI: 10.4161/gmcr.25285] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Long double-stranded RNAs (long dsRNAs) are precursors for the effector molecules of sequence-specific RNA-based gene silencing in eukaryotes. Plant cells can contain numerous endogenous long dsRNAs. This study demonstrates that such endogenous long dsRNAs in plants have sequence complementarity to human genes. Many of these complementary long dsRNAs have perfect sequence complementarity of at least 21 nucleotides to human genes; enough complementarity to potentially trigger gene silencing in targeted human cells if delivered in functional form. However, the number and diversity of long dsRNA molecules in plant tissue from crops such as lettuce, tomato, corn, soy and rice with complementarity to human genes that have a long history of safe consumption supports a conclusion that long dsRNAs do not present a significant dietary risk.
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72
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Alfonso-Pecchio A, Garcia M, Leonardi R, Jackowski S. Compartmentalization of mammalian pantothenate kinases. PLoS One 2012; 7:e49509. [PMID: 23152917 PMCID: PMC3496714 DOI: 10.1371/journal.pone.0049509] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/09/2012] [Indexed: 11/19/2022] Open
Abstract
The pantothenate kinases (PanK) catalyze the first and the rate-limiting step in coenzyme A (CoA) biosynthesis and regulate the amount of CoA in tissues by differential isoform expression and allosteric interaction with metabolic ligands. The four human and mouse PanK proteins share a homologous carboxy-terminal catalytic domain, but differ in their amino-termini. These unique termini direct the isoforms to different subcellular compartments. PanK1α isoforms were exclusively nuclear, with preferential association with the granular component of the nucleolus during interphase. PanK1α also associated with the perichromosomal region in condensing chromosomes during mitosis. The PanK1β and PanK3 isoforms were cytosolic, with a portion of PanK1β associated with clathrin-associated vesicles and recycling endosomes. Human PanK2, known to associate with mitochondria, was specifically localized to the intermembrane space. Human PanK2 was also detected in the nucleus, and functional nuclear localization and export signals were identified and experimentally confirmed. Nuclear PanK2 trafficked from the nucleus to the mitochondria, but not in the other direction, and was absent from the nucleus during G2 phase of the cell cycle. The localization of human PanK2 in these two compartments was in sharp contrast to mouse PanK2, which was exclusively cytosolic. These data demonstrate that PanK isoforms are differentially compartmentalized allowing them to sense CoA homeostasis in different cellular compartments and enable interaction with regulatory ligands produced in these same locations.
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Affiliation(s)
- Adolfo Alfonso-Pecchio
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Matthew Garcia
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Roberta Leonardi
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Suzanne Jackowski
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- * E-mail:
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73
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Siudeja K, Grzeschik NA, Rana A, de Jong J, Sibon OCM. Cofilin/Twinstar phosphorylation levels increase in response to impaired coenzyme a metabolism. PLoS One 2012; 7:e43145. [PMID: 22912811 PMCID: PMC3422318 DOI: 10.1371/journal.pone.0043145] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/19/2012] [Indexed: 11/19/2022] Open
Abstract
Coenzyme A (CoA) is a pantothenic acid-derived metabolite essential for many fundamental cellular processes including energy, lipid and amino acid metabolism. Pantothenate kinase (PANK), which catalyses the first step in the conversion of pantothenic acid to CoA, has been associated with a rare neurodegenerative disorder PKAN. However, the consequences of impaired PANK activity are poorly understood. Here we use Drosophila and human neuronal cell cultures to show how PANK deficiency leads to abnormalities in F-actin organization. Cells with reduced PANK activity are characterized by abnormally high levels of phosphorylated cofilin, a conserved actin filament severing protein. The increased levels of phospho-cofilin coincide with morphological changes of PANK-deficient Drosophila S2 cells and human neuronal SHSY-5Y cells. The latter exhibit also markedly reduced ability to form neurites in culture--a process that is strongly dependent on actin remodeling. Our results reveal a novel and conserved link between a metabolic biosynthesis pathway, and regulation of cellular actin dynamics.
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Affiliation(s)
| | | | | | | | - Ody C. M. Sibon
- Department of Cell Biology, Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- * E-mail:
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Garcia M, Leonardi R, Zhang YM, Rehg JE, Jackowski S. Germline deletion of pantothenate kinases 1 and 2 reveals the key roles for CoA in postnatal metabolism. PLoS One 2012; 7:e40871. [PMID: 22815849 PMCID: PMC3398950 DOI: 10.1371/journal.pone.0040871] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 06/16/2012] [Indexed: 12/22/2022] Open
Abstract
Pantothenate kinase (PanK) phosphorylates pantothenic acid (vitamin B5) and controls the overall rate of coenzyme A (CoA) biosynthesis. Pank1 gene deletion in mice results in a metabolic phenotype where fatty acid oxidation and gluconeogenesis are impaired in the fasted state, leading to mild hypoglycemia. Inactivating mutations in the human PANK2 gene lead to childhood neurodegeneration, but Pank2 gene inactivation in mice does not elicit a phenotype indicative of the neuromuscular symptoms or brain iron accumulation that accompany the human disease. Pank1/Pank2 double knockout (dKO) mice were derived to determine if the mild phenotypes of the single knockout mice are due to the ability of the two isoforms to compensate for each other in CoA biosynthesis. Postnatal development was severely affected in the dKO mice. The dKO pups developed progressively severe hypoglycemia and hyperketonemia by postnatal day 10 leading to death by day 17. Hyperketonemia arose from impaired whole-body ketone utilization illustrating the requirement for CoA in energy generation from ketones. dKO pups had reduced CoA and decreased fatty acid oxidation coupled with triglyceride accumulation in liver. dKO hepatocytes could not maintain the NADH levels compared to wild-type hepatocytes. These results revealed an important link between CoA and NADH levels, which was reflected by deficiencies in hepatic oleate synthesis and gluconeogenesis. The data indicate that PanK1 and PanK2 can compensate for each other to supply tissue CoA, but PanK1 is more important to CoA levels in liver whereas PanK2 contributes more to CoA synthesis in the brain.
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Affiliation(s)
- Matthew Garcia
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Roberta Leonardi
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Yong-Mei Zhang
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Suzanne Jackowski
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- * E-mail:
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Mennigen JA, Panserat S, Larquier M, Plagnes-Juan E, Medale F, Seiliez I, Skiba-Cassy S. Postprandial regulation of hepatic microRNAs predicted to target the insulin pathway in rainbow trout. PLoS One 2012; 7:e38604. [PMID: 22701681 PMCID: PMC3368902 DOI: 10.1371/journal.pone.0038604] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 05/11/2012] [Indexed: 01/22/2023] Open
Abstract
Rainbow trout are carnivorous fish and poor metabolizers of carbohydrates, which established this species as a model organism to study the comparative physiology of insulin. Following the recent characterisation of key roles of several miRNAs in the insulin action on hepatic intermediary metabolism in mammalian models, we investigated the hypothesis that hepatic miRNA expression is postprandially regulated in the rainbow trout and temporally coordinated in the context of insulin-mediated regulation of metabolic gene expression in the liver. To address this hypothesis, we used a time-course experiment in which rainbow trout were fed a commercial diet after short-term fasting. We investigated hepatic miRNA expression, activation of the insulin pathway, and insulin regulated metabolic target genes at several time points. Several miRNAs which negatively regulate hepatic insulin signaling in mammalian model organisms were transiently increased 4 h after the meal, consistent with a potential role in acute postprandial negative feed-back regulation of the insulin pathway and attenuation of gluconeogenic gene expression. We equally observed a transient increase in omy- miRNA-33 and omy-miRNA-122b 4 h after feeding, whose homologues have potent lipogenic roles in the liver of mammalian model systems. A concurrent increase in the activity of the hepatic insulin signaling pathway and the expression of lipogenic genes (srebp1c, fas, acly) was equally observed, while lipolytic gene expression (cpt1a and cpt1b) decreased significantly 4 h after the meal. This suggests lipogenic roles of omy-miRNA-33 and omy-miRNA-122b may be conserved between rainbow trout and mammals and that these miRNAs may furthermore contribute to acute postprandial regulation of de novo hepatic lipid synthesis in rainbow trout. These findings provide a framework for future research of miRNA regulation of hepatic metabolism in trout and will help to further elucidate the metabolic phenotype of rainbow trout.
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Affiliation(s)
- Jan A. Mennigen
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Stéphane Panserat
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Mélanie Larquier
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Elisabeth Plagnes-Juan
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Françoise Medale
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Iban Seiliez
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
| | - Sandrine Skiba-Cassy
- UMR1067 Nutrition, Métabolisme, Aquaculture, Institut National de la Recherche Agronomique, Saint-Pée-sur-Nivelle, Pyrénées-Atlantiques, France
- * E-mail:
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76
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Prohaska R, Sibon OC, Rudnicki DD, Danek A, Hayflick SJ, Verhaag EM, Jan J V, Margolis RL, Walker RH. Brain, blood, and iron: perspectives on the roles of erythrocytes and iron in neurodegeneration. Neurobiol Dis 2012; 46:607-24. [PMID: 22426390 PMCID: PMC3352961 DOI: 10.1016/j.nbd.2012.03.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 01/17/2012] [Accepted: 03/01/2012] [Indexed: 12/20/2022] Open
Abstract
The terms "neuroacanthocytosis" (NA) and "neurodegeneration with brain iron accumulation" (NBIA) both refer to groups of genetically heterogeneous disorders, classified together due to similarities of their phenotypic or pathological findings. Even collectively, the disorders that comprise these sets are exceedingly rare and challenging to study. The NBIA disorders are defined by their appearance on brain magnetic resonance imaging, with iron deposition in the basal ganglia. Clinical features vary, but most include a movement disorder. New causative genes are being rapidly identified; however, the mechanisms by which mutations cause iron accumulation and neurodegeneration are not well understood. NA syndromes are also characterized by a progressive movement disorder, accompanied by cognitive and psychiatric features, resulting from mutations in a number of genes whose roles are also basically unknown. An overlapping feature of the two groups, NBIA and NA, is the occurrence of acanthocytes, spiky red cells with a poorly-understood membrane dysfunction. In this review we summarise recent developments in this field, specifically insights into cellular mechanisms and from animal models. Cell membrane research may shed light upon the significance of the erythrocyte abnormality, and upon possible connections between the two sets of disorders. Shared pathophysiologic mechanisms may lead to progress in the understanding of other types of neurodegeneration.
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Affiliation(s)
- Rainer Prohaska
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Ody C.M. Sibon
- Section of Radiation & Stress Cell Biology, Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Dobrila D. Rudnicki
- Department of Psychiatry, Division of Neurobiology, Laboratory of Genetic Neurobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Adrian Danek
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität, Munich, Germany
| | - Susan J. Hayflick
- Departments of Molecular & Medical Genetics, Pediatrics and Neurology, Oregon Health & Science University, Portland OR USA
| | - Esther M. Verhaag
- Section of Radiation & Stress Cell Biology, Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Vonk Jan J
- Section of Radiation & Stress Cell Biology, Department of Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Russell L. Margolis
- Department of Psychiatry, Division of Neurobiology, Laboratory of Genetic Neurobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruth H. Walker
- Departments of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA and Mount Sinai School of Medicine, New York, NY USA
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Siudeja K, Srinivasan B, Xu L, Rana A, de Jong J, Nollen EAA, Jackowski S, Sanford L, Hayflick S, Sibon OCM. Impaired Coenzyme A metabolism affects histone and tubulin acetylation in Drosophila and human cell models of pantothenate kinase associated neurodegeneration. EMBO Mol Med 2011; 3:755-66. [PMID: 21998097 PMCID: PMC3377114 DOI: 10.1002/emmm.201100180] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/31/2011] [Accepted: 09/02/2011] [Indexed: 11/10/2022] Open
Abstract
Pantothenate kinase-associated neurodegeneration (PKAN is a neurodegenerative disease with unresolved pathophysiology. Previously, we observed reduced Coenzyme A levels in a Drosophila model for PKAN. Coenzyme A is required for acetyl-Coenzyme A synthesis and acyl groups from the latter are transferred to lysine residues of proteins, in a reaction regulated by acetyltransferases. The tight balance between acetyltransferases and their antagonistic counterparts histone deacetylases is a well-known determining factor for the acetylation status of proteins. However, the influence of Coenzyme A levels on protein acetylation is unknown. Here we investigate whether decreased levels of the central metabolite Coenzyme A induce alterations in protein acetylation and whether this correlates with specific phenotypes of PKAN models. We show that in various organisms proper Coenzyme A metabolism is required for maintenance of histone- and tubulin acetylation, and decreased acetylation of these proteins is associated with an impaired DNA damage response, decreased locomotor function and decreased survival. Decreased protein acetylation and the concurrent phenotypes are partly rescued by pantethine and HDAC inhibitors, suggesting possible directions for future PKAN therapy development.
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Affiliation(s)
- Katarzyna Siudeja
- Department of Cell Biology, Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Leonardi R, Zhang YM, Yun MK, Zhou R, Zeng FY, Lin W, Cui J, Chen T, Rock CO, White SW, Jackowski S. Modulation of pantothenate kinase 3 activity by small molecules that interact with the substrate/allosteric regulatory domain. ACTA ACUST UNITED AC 2011; 17:892-902. [PMID: 20797618 DOI: 10.1016/j.chembiol.2010.06.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/04/2010] [Accepted: 06/07/2010] [Indexed: 11/30/2022]
Abstract
Pantothenate kinase (PanK) catalyzes the rate-controlling step in coenzyme A (CoA) biosynthesis. PanK3 is stringently regulated by acetyl-CoA and uses an ordered kinetic mechanism with ATP as the leading substrate. Biochemical analysis of site-directed mutants indicates that pantothenate binds in a tunnel adjacent to the active site that is occupied by the pantothenate moiety of the acetyl-CoA regulator in the PanK3acetyl-CoA binary complex. A high-throughput screen for PanK3 inhibitors and activators was applied to a bioactive compound library. Thiazolidinediones, sulfonylureas and steroids were inhibitors, and fatty acyl-amides and tamoxifen were activators. The PanK3 activators and inhibitors either stimulated or repressed CoA biosynthesis in HepG2/C3A cells. The flexible allosteric acetyl-CoA regulatory domain of PanK3 also binds the substrates, pantothenate and pantetheine, and small molecule inhibitors and activators to modulate PanK3 activity.
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Affiliation(s)
- Roberta Leonardi
- Department of Infectious Diseases, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
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79
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Goetzman ES. Modeling Disorders of Fatty Acid Metabolism in the Mouse. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 100:389-417. [DOI: 10.1016/b978-0-12-384878-9.00010-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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80
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Coenzyme A and its thioester pools in fasted and fed rat tissues. Biochem Biophys Res Commun 2010; 402:158-62. [PMID: 20933504 DOI: 10.1016/j.bbrc.2010.10.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/04/2010] [Indexed: 11/20/2022]
Abstract
Levels of three coenzyme A (CoA) molecular species, i.e., nonesterified CoA (CoASH), acetyl-CoA, and malonyl-CoA, in fasted and fed rat tissues were analyzed by the acyl-CoA cycling method which makes detection possible at the pmol level. Malonyl-CoA in brain tissues readily increased with feeding, and inversely, acetyl-CoA decreased. This phenomenon occurred in the cerebral cortex, hippocampus, cerebellum, and medulla oblongata, as well as in the hypothalamus which controls energy balance by monitoring malonyl-CoA. In the non-brain tissues, the sizes of the acetyl-CoA, malonyl-CoA, and CoASH pools depended on the tissues. The total CoA pools consisting of the above three CoA species in the liver, heart, and brown adipose tissue were larger and those of the perirenal, epididymal, and ovarian adipose tissues were much smaller, compared with those of other tissues including brain tissues. In addition, the response of each CoA pool to feeding was not uniform, suggesting that the tissue-specific metabolism individually functions in the non-brain tissues. Thus, a comprehensive analysis of thirteen types of rat tissue revealed that CoA pools have different sizes and showed a different response to fasting and feeding depending on the tissue.
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81
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Leonardi R, Rehg JE, Rock CO, Jackowski S. Pantothenate kinase 1 is required to support the metabolic transition from the fed to the fasted state. PLoS One 2010; 5:e11107. [PMID: 20559429 PMCID: PMC2885419 DOI: 10.1371/journal.pone.0011107] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 05/24/2010] [Indexed: 12/25/2022] Open
Abstract
Coenzyme A (CoA) biosynthesis is regulated by the pantothenate kinases (PanK), of which there are four active isoforms. The PanK1 isoform is selectively expressed in liver and accounted for 40% of the total PanK activity in this organ. CoA synthesis was limited using a Pank1(-/-) knockout mouse model to determine whether the regulation of CoA levels was critical to liver function. The elimination of PanK1 reduced hepatic CoA levels, and fasting triggered a substantial increase in total hepatic CoA in both Pank1(-/-) and wild-type mice. The increase in hepatic CoA during fasting was blunted in the Pank1(-/-) mouse, and resulted in reduced fatty acid oxidation as evidenced by abnormally high accumulation of long-chain acyl-CoAs, acyl-carnitines, and triglycerides in the form of lipid droplets. The Pank1(-/-) mice became hypoglycemic during a fast due to impaired gluconeogenesis, although ketogenesis was normal. These data illustrate the importance of PanK1 and elevated liver CoA levels during fasting to support the metabolic transition from glucose utilization and fatty acid synthesis to gluconeogenesis and fatty acid oxidation. The findings also suggest that PanK1 may be a suitable target for therapeutic intervention in metabolic disorders that feature hyperglycemia and hypertriglyceridemia.
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Affiliation(s)
- Roberta Leonardi
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Charles O. Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Suzanne Jackowski
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
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82
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Pantethine rescues a Drosophila model for pantothenate kinase-associated neurodegeneration. Proc Natl Acad Sci U S A 2010; 107:6988-93. [PMID: 20351285 DOI: 10.1073/pnas.0912105107] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Pantothenate kinase-associated neurodegeneration (PKAN), a progressive neurodegenerative disorder, is associated with impairment of pantothenate kinase function. Pantothenate kinase is the first enzyme required for de novo synthesis of CoA, an essential metabolic cofactor. The pathophysiology of PKAN is not understood, and there is no cure to halt or reverse the symptoms of this devastating disease. Recently, we and others presented a PKAN Drosophila model, and we demonstrated that impaired function of pantothenate kinase induces a neurodegenerative phenotype and a reduced lifespan. We have explored this Drosophila model further and have demonstrated that impairment of pantothenate kinase is associated with decreased levels of CoA, mitochondrial dysfunction, and increased protein oxidation. Furthermore, we searched for compounds that can rescue pertinent phenotypes of the Drosophila PKAN model and identified pantethine. Pantethine feeding restores CoA levels, improves mitochondrial function, rescues brain degeneration, enhances locomotor abilities, and increases lifespan. We show evidence for the presence of a de novo CoA biosynthesis pathway in which pantethine is used as a precursor compound. Importantly, this pathway is effective in the presence of disrupted pantothenate kinase function. Our data suggest that pantethine may serve as a starting point to develop a possible treatment for PKAN.
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83
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Moiseenok AG, Omel’yanchik SN, Sheval’e AA, Katkovskaya IN, El’chaninova MA, Pekhovskaya TA, Kovalenchik IL. Coenzyme A, acyl-CoA, and the glutathione system in CNS structures exposed to homopantothenate or in aluminum neurotoxicity. NEUROCHEM J+ 2010. [DOI: 10.1134/s181971241001006x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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84
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Wu Z, Li C, Lv S, Zhou B. Pantothenate kinase-associated neurodegeneration: insights from a Drosophila model. Hum Mol Genet 2009; 18:3659-72. [PMID: 19602483 DOI: 10.1093/hmg/ddp314] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pantothenate-Kinase-Associated-Neurodegeneration (PKAN) is a devastating disease, resulting from mutations in pantothenate kinase 2 (PANK2), one of the four human pantothenate kinase genes (PANK1-4). Interestingly, PanK2 appears to be the only mitochondria-targeted human PanK. It is unknown whether the mitochondria-targeted PanK is associated with any unique function, nor whether PKAN is due solely to the loss of pantothenate kinase activity. Drosophila PANK [fumble (fbl)] encodes several isoforms of pantothenate kinase products, one of which localizes to mitochondria and the others cytosol. fbl flies exhibit many characteristic features reminiscent of PKAN patients. Various forms of Drosophila fbl and human PANK2 were introduced into fbl flies to study their in vivo functions. Only mitochondria-targeted Fbl or human PanK2 was able to rescue fbl mutation, with the rescuing ability sensitive to the expression level of the transgene. Transgenic lines with low expression of normal Fbl or PanK2 displayed similar phenotypes as PANK2 mutant transgenic flies. These PanK2 mutants all showed reduced and phenotype severity-correlated in vitro pantothenate kinase activities. Amazingly, cytosolic PanK3 and PanK4 could mostly, but not fully, rescue fbl defects except the male sterility. Therefore, fbl appears to be the orthologue of human PANK2, and PanK2 is functionally more potent than PanK3 and PanK4 in vivo. We suggest that mitochondria-located pantothenate kinase is required to achieve the maximal enzymatic activity to fulfill the most challenging task such as maintaining male fertility and optimal neuronal functions, and PKAN features are mainly due to the reduction of the total cellular pantothenate kinase activity in the most susceptible regions.
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Affiliation(s)
- Zhihao Wu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
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85
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Sabatti C, Service SK, Hartikainen AL, Pouta A, Ripatti S, Brodsky J, Jones CG, Zaitlen NA, Varilo T, Kaakinen M, Sovio U, Ruokonen A, Laitinen J, Jakkula E, Coin L, Hoggart C, Collins A, Turunen H, Gabriel S, Elliot P, McCarthy MI, Daly MJ, Järvelin MR, Freimer NB, Peltonen L. Genome-wide association analysis of metabolic traits in a birth cohort from a founder population. Nat Genet 2008; 41:35-46. [PMID: 19060910 DOI: 10.1038/ng.271] [Citation(s) in RCA: 552] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 10/03/2008] [Indexed: 02/06/2023]
Abstract
Genome-wide association studies (GWAS) of longitudinal birth cohorts enable joint investigation of environmental and genetic influences on complex traits. We report GWAS results for nine quantitative metabolic traits (triglycerides, high-density lipoprotein, low-density lipoprotein, glucose, insulin, C-reactive protein, body mass index, and systolic and diastolic blood pressure) in the Northern Finland Birth Cohort 1966 (NFBC1966), drawn from the most genetically isolated Finnish regions. We replicate most previously reported associations for these traits and identify nine new associations, several of which highlight genes with metabolic functions: high-density lipoprotein with NR1H3 (LXRA), low-density lipoprotein with AR and FADS1-FADS2, glucose with MTNR1B, and insulin with PANK1. Two of these new associations emerged after adjustment of results for body mass index. Gene-environment interaction analyses suggested additional associations, which will require validation in larger samples. The currently identified loci, together with quantified environmental exposures, explain little of the trait variation in NFBC1966. The association observed between low-density lipoprotein and an infrequent variant in AR suggests the potential of such a cohort for identifying associations with both common, low-impact and rarer, high-impact quantitative trait loci.
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Affiliation(s)
- Chiara Sabatti
- Department of Human Genetics and Los Angeles, Los Angeles, California 90095, USA
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86
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Bibliography. Current world literature. Lipid metabolism. Curr Opin Lipidol 2008; 19:314-21. [PMID: 18460925 DOI: 10.1097/mol.0b013e328303e27e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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87
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Mitchell GA, Gauthier N, Lesimple A, Wang SP, Mamer O, Qureshi I. Hereditary and acquired diseases of acyl-coenzyme A metabolism. Mol Genet Metab 2008; 94:4-15. [PMID: 18337138 DOI: 10.1016/j.ymgme.2007.12.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 12/20/2007] [Accepted: 12/20/2007] [Indexed: 01/23/2023]
Abstract
Coenzyme A (CoA) sequestration, toxicity or redistribution (CASTOR) is predicted to occur in many hereditary and acquired conditions in which the degradation of organic acyl esters of CoA is impaired. The resulting accumulation of CoA esters and reduction of acetyl-CoA and free CoA (CoASH) will then trigger a cascade of reactions leading to clinical disease. Most conditions detected by expanded neonatal screening are CASTOR diseases. We review acyl-CoA metabolism, including CoASH synthesis, transesterification of acyl-CoAs to glycine, glutamate or l-carnitine and hydrolysis of CoA esters. Because acyl-CoAs do not cross biological membranes, their main toxicity is intracellular, primarily within mitochondria. Treatment measures directed towards removal of circulating metabolites do not address this central problem of intracellular acyl-CoA accumulation. Treatments usually involve the restriction of dietary precursors and administration of agents like l-carnitine and glycine, which can accept the transfer of acyl groups from acyl-CoA, liberating CoASH. Many hereditary CASTOR patients are chronically ill, with persistent symptoms and continuously abnormal metabolites in blood and urine despite good compliance with treatment. Conversely, asymptomatic patients are also common in hereditary CASTOR conditions. Future challenges include the understanding of pathophysiologic mechanisms in CASTOR diseases, the discovery of reliable predictors of outcome in individual patients and the establishment of therapeutic trials with sufficient numbers of patients to permit solid therapeutic conclusions.
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Affiliation(s)
- Grant A Mitchell
- Division of Medical Genetics, CHU Sainte-Justine, 3175 Côte Sainte-Catherine Road, Montréal, Que., Canada H1R 2A6.
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88
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Bosveld F, Rana A, van der Wouden PE, Lemstra W, Ritsema M, Kampinga HH, Sibon OCM. De novo CoA biosynthesis is required to maintain DNA integrity during development of the Drosophila nervous system. Hum Mol Genet 2008; 17:2058-69. [PMID: 18407920 DOI: 10.1093/hmg/ddn105] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In a forward genetic screen in Drosophila melanogaster, aimed to identify genes required for normal locomotor function, we isolated dPPCS (the second enzyme of the Coenzyme A biosynthesis pathway). The entire Drosophila CoA synthesis route was dissected, annotated and additional CoA mutants were obtained (dPANK/fumble) or generated (dPPAT-DPCK). Drosophila CoA mutants suffer from neurodegeneration, altered lipid homeostasis and the larval brains display increased apoptosis. Also, de novo CoA biosynthesis is required to maintain DNA integrity during the development of the central nervous system. In humans, mutations in the PANK2 gene, the first enzyme in the CoA synthesis route, are associated with pantothenate kinase-associated neurodegeneration. Currently, the pathogenesis of this neurodegenerative disease is poorly understood. We provide the first comprehensive analysis of the physiological implications of mutations in the entire CoA biosynthesis route in an animal model system. Surprisingly, our findings reveal a major role of this conserved pathway in maintaining DNA and cellular integrity, explaining how impaired CoA synthesis during CNS development can elicit a neurodegenerative phenotype.
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Affiliation(s)
- Floris Bosveld
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Centre Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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89
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Xiang RL, Yang YL, Zuo J, Xiao XH, Chang YS, De Fang F. PanK4 inhibits pancreatic β-cell apoptosis by decreasing the transcriptional level of pro-caspase-9. Cell Res 2007; 17:966-8. [DOI: 10.1038/cr.2007.93] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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90
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Leonardi R, Zhang YM, Lykidis A, Rock CO, Jackowski S. Localization and regulation of mouse pantothenate kinase 2. FEBS Lett 2007; 581:4639-44. [PMID: 17825826 PMCID: PMC2034339 DOI: 10.1016/j.febslet.2007.08.056] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 08/21/2007] [Accepted: 08/27/2007] [Indexed: 11/16/2022]
Abstract
Coenzyme A (CoA) biosynthesis is initiated by pantothenate kinase (PanK) and CoA levels are controlled through differential expression and feedback regulation of PanK isoforms. PanK2 is a mitochondrial protein in humans, but comparative genomics revealed that acquisition of a mitochondrial targeting signal was limited to primates. Human and mouse PanK2 possessed similar biochemical properties, with inhibition by acetyl-CoA and activation by palmitoylcarnitine. Mouse PanK2 localized in the cytosol, and the expression of PanK2 was higher in human brain compared to mouse brain. Differences in expression and subcellular localization should be considered in developing a mouse model for human PanK2 deficiency.
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Affiliation(s)
- Roberta Leonardi
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
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