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Colombaioni L, Campanella B, Nieri R, Onor M, Benedetti E, Bramanti E. Time-dependent influence of high glucose environment on the metabolism of neuronal immortalized cells. Anal Biochem 2022; 645:114607. [DOI: 10.1016/j.ab.2022.114607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 02/07/2022] [Accepted: 02/17/2022] [Indexed: 11/16/2022]
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Molecular mechanisms mediating relapse following ivosidenib monotherapy in IDH1-mutant relapsed or refractory AML. Blood Adv 2021; 4:1894-1905. [PMID: 32380538 DOI: 10.1182/bloodadvances.2020001503] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/18/2020] [Indexed: 12/12/2022] Open
Abstract
Isocitrate dehydrogenase (IDH) 1 and 2 mutations result in overproduction of D-2-hydroxyglutarate (2-HG) and impaired cellular differentiation. Ivosidenib, a targeted mutant IDH1 (mIDH1) enzyme inhibitor, can restore normal differentiation and results in clinical responses in a subset of patients with mIDH1 relapsed/refractory (R/R) acute myeloid leukemia (AML). We explored mechanisms of ivosidenib resistance in 174 patients with confirmed mIDH1 R/R AML from a phase 1 trial. Receptor tyrosine kinase (RTK) pathway mutations were associated with primary resistance to ivosidenib. Multiple mechanisms contributed to acquired resistance, particularly outgrowth of RTK pathway mutations and 2-HG-restoring mutations (second-site IDH1 mutations, IDH2 mutations). Observation of multiple concurrent mechanisms in individual patients underscores the complex biology of resistance and has important implications for rational combination therapy design. This trial was registered at www.clinicaltrials.gov as #NCT02074839.
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L2HGDH Missense Variant in a Cat with L-2-Hydroxyglutaric Aciduria. Genes (Basel) 2021; 12:genes12050682. [PMID: 34062805 PMCID: PMC8147296 DOI: 10.3390/genes12050682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 11/17/2022] Open
Abstract
A 7-month-old, spayed female, domestic longhair cat with L-2-hydroxyglutaric aciduria (L-2-HGA) was investigated. The aim of this study was to investigate the clinical signs, metabolic changes and underlying genetic defect. The owner of the cat reported a 4-month history of multiple paroxysmal seizure-like episodes, characterized by running around the house, often in circles, with abnormal behavior, bumping into obstacles, salivating and often urinating. The episodes were followed by a period of disorientation and inappetence. Neurological examination revealed an absent bilateral menace response. Routine blood work revealed mild microcytic anemia but biochemistry, ammonia, lactate and pre- and post-prandial bile acids were unremarkable. MRI of the brain identified multifocal, bilaterally symmetrical and T2-weighted hyperintensities within the prosencephalon, mesencephalon and metencephalon, primarily affecting the grey matter. Urinary organic acids identified highly increased levels of L-2-hydroxyglutaric acid. The cat was treated with the anticonvulsants levetiracetam and phenobarbitone and has been seizure-free for 16 months. We sequenced the genome of the affected cat and compared the data to 48 control genomes. L2HGDH, coding for L-2-hydroxyglutarate dehydrogenase, was investigated as the top functional candidate gene. This search revealed a single private protein-changing variant in the affected cat. The identified homozygous variant, XM_023255678.1:c.1301A>G, is predicted to result in an amino acid change in the L2HGDH protein, XP_023111446.1:p.His434Arg. The available clinical and biochemical data together with current knowledge about L2HGDH variants and their functional impact in humans and dogs allow us to classify the p.His434Arg variant as a causative variant for the observed neurological signs in this cat.
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Veiga‐da‐Cunha M, Van Schaftingen E, Bommer GT. Inborn errors of metabolite repair. J Inherit Metab Dis 2020; 43:14-24. [PMID: 31691304 PMCID: PMC7041631 DOI: 10.1002/jimd.12187] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/18/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022]
Abstract
It is traditionally assumed that enzymes of intermediary metabolism are extremely specific and that this is sufficient to prevent the production of useless and/or toxic side-products. Recent work indicates that this statement is not entirely correct. In reality, enzymes are not strictly specific, they often display weak side activities on intracellular metabolites (substrate promiscuity) that resemble their physiological substrate or slowly catalyse abnormal reactions on their physiological substrate (catalytic promiscuity). They thereby produce non-classical metabolites that are not efficiently metabolised by conventional enzymes. In an increasing number of cases, metabolite repair enzymes are being discovered that serve to eliminate these non-classical metabolites and prevent their accumulation. Metabolite repair enzymes also eliminate non-classical metabolites that are formed through spontaneous (ie, not enzyme-catalysed) reactions. Importantly, genetic deficiencies in several metabolite repair enzymes lead to 'inborn errors of metabolite repair', such as L-2-hydroxyglutaric aciduria, D-2-hydroxyglutaric aciduria, 'ubiquitous glucose-6-phosphatase' (G6PC3) deficiency, the neutropenia present in Glycogen Storage Disease type Ib or defects in the enzymes that repair the hydrated forms of NADH or NADPH. Metabolite repair defects may be difficult to identify as such, because the mutated enzymes are non-classical enzymes that act on non-classical metabolites, which in some cases accumulate only inside the cells, and at rather low, yet toxic, concentrations. It is therefore likely that many additional metabolite repair enzymes remain to be discovered and that many diseases of metabolite repair still await elucidation.
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Affiliation(s)
| | - Emile Van Schaftingen
- de Duve InstituteUniversité Catholique de Louvain (UCLouvain)BrusselsBelgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO)UCLouvainBrusselsBelgium
| | - Guido T. Bommer
- de Duve InstituteUniversité Catholique de Louvain (UCLouvain)BrusselsBelgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO)UCLouvainBrusselsBelgium
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Willmes DM, Kurzbach A, Henke C, Schumann T, Zahn G, Heifetz A, Jordan J, Helfand SL, Birkenfeld AL. The longevity gene INDY ( I 'm N ot D ead Y et) in metabolic control: Potential as pharmacological target. Pharmacol Ther 2018; 185:1-11. [DOI: 10.1016/j.pharmthera.2017.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Klotz J, Porter BE, Colas C, Schlessinger A, Pajor AM. Mutations in the Na(+)/citrate cotransporter NaCT (SLC13A5) in pediatric patients with epilepsy and developmental delay. Mol Med 2016; 22:molmed.2016.00077. [PMID: 27261973 DOI: 10.2119/molmed.2016.00077] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/23/2016] [Indexed: 01/13/2023] Open
Abstract
Mutations in the SLC13A5 gene that codes for the Na(+)/citrate cotransporter, NaCT, are associated with early onset epilepsy, developmental delay and tooth dysplasia in children. In the present study we identify additional SLC13A5 mutations in nine epilepsy patients from six families. To better characterize the syndrome, families with affected children answered questions about the scope of illness and treatment strategies. There are currently no effective treatments, but some anti-epileptic drugs targeting the GABA system reduce seizure frequency. Acetazolamide, a carbonic anhydrase inhibitor and atypical anti-seizure medication decreases seizures in 4 patients. In contrast to previous reports, the ketogenic diet and fasting produce worsening of symptoms. The effects of the mutations on NaCT transport function and protein expression were examined by transient transfections of COS-7 cells. There was no transport activity from any of the mutant transporters, although some of the mutant transporter proteins were present on the plasma membrane. The structural model of NaCT suggests that these mutations can affect helix packing or substrate binding. We tested various treatments, including chemical chaperones and low temperatures, but none improve transport function in the NaCT mutants. Interestingly, coexpression of NaCT and the mutants results in decreased protein expression and activity of the wild-type transporter, indicating functional interaction. In conclusion, our study has identified additional SLC13A5 mutations in patients with chronic epilepsy starting in the neonatal period, with the mutations producing inactive Na(+)/citrate transporters.
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Affiliation(s)
- Jenna Klotz
- Department of Neurology, Stanford University School of Medicine, Palo Alto, CA 94305
| | - Brenda E Porter
- Department of Neurology, Stanford University School of Medicine, Palo Alto, CA 94305
| | - Claire Colas
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Avner Schlessinger
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Ana M Pajor
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla, CA 92130-0718
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7
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Zwart R, Peeva PM, Rong JX, Sher E. Electrophysiological characterization of human and mouse sodium-dependent citrate transporters (NaCT/SLC13A5) reveal species differences with respect to substrate sensitivity and cation dependence. J Pharmacol Exp Ther 2015; 355:247-54. [PMID: 26324167 DOI: 10.1124/jpet.115.226902] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/28/2015] [Indexed: 01/01/2023] Open
Abstract
The citric acid cycle intermediate citrate plays a crucial role in metabolic processes such as fatty acid synthesis, glucose metabolism, and β-oxidation. Citrate is imported from the circulation across the plasma membrane into liver cells mainly by the sodium-dependent citrate transporter (NaCT; SLC13A5). Deletion of NaCT from mice led to metabolic changes similar to caloric restriction; therefore, NaCT has been proposed as an attractive therapeutic target for the treatment of obesity and type 2 diabetes. In this study, we expressed mouse and human NaCT into Xenopus oocytes and examined some basic functional properties of those transporters. Interestingly, striking differences were found between mouse and human NaCT with respect to their sensitivities to citric acid cycle intermediates as substrates for these transporters. Mouse NaCT had at least 20- to 800-fold higher affinity for these intermediates than human NaCT. Mouse NaCT is fully active at physiologic plasma levels of citrate, but its human counterpart is not. Replacement of extracellular sodium by other monovalent cations revealed that human NaCT was markedly less dependent on extracellular sodium than mouse NaCT. The low sensitivity of human NaCT for citrate raises questions about the translatability of this target from the mouse to the human situation and raises doubts about the validity of this transporter as a therapeutic target for the treatment of metabolic diseases in humans.
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Affiliation(s)
- Ruud Zwart
- Neuroscience Discovery Research, Lilly Research Centre, Eli Lilly and Company, Windlesham, United Kingdom (R.Z., P.M.P., E.S.); and Lilly China Research and Development Center, Eli Lilly and Company, Shanghai, China (J.X.R.)
| | - Polina M Peeva
- Neuroscience Discovery Research, Lilly Research Centre, Eli Lilly and Company, Windlesham, United Kingdom (R.Z., P.M.P., E.S.); and Lilly China Research and Development Center, Eli Lilly and Company, Shanghai, China (J.X.R.)
| | - James X Rong
- Neuroscience Discovery Research, Lilly Research Centre, Eli Lilly and Company, Windlesham, United Kingdom (R.Z., P.M.P., E.S.); and Lilly China Research and Development Center, Eli Lilly and Company, Shanghai, China (J.X.R.)
| | - Emanuele Sher
- Neuroscience Discovery Research, Lilly Research Centre, Eli Lilly and Company, Windlesham, United Kingdom (R.Z., P.M.P., E.S.); and Lilly China Research and Development Center, Eli Lilly and Company, Shanghai, China (J.X.R.)
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Napoli E, Tassone F, Wong S, Angkustsiri K, Simon TJ, Song G, Giulivi C. Mitochondrial Citrate Transporter-dependent Metabolic Signature in the 22q11.2 Deletion Syndrome. J Biol Chem 2015. [PMID: 26221035 DOI: 10.1074/jbc.m115.672360] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The congenital disorder 22q11.2 deletion syndrome (22qDS), characterized by a hemizygous deletion of 1.5-3 Mb on chromosome 22 at locus 11.2, is the most common microdeletion disorder (estimated prevalence of 1 in 4000) and the second risk factor for schizophrenia. Nine of ∼30 genes involved in 22qDS have the potential of disrupting mitochondrial metabolism (COMT, UFD1L, DGCR8, MRPL40, PRODH, SLC25A1, TXNRD2, T10, and ZDHHC8). Deficits in bioenergetics during early postnatal brain development could set the basis for a disrupted neuronal metabolism or synaptic signaling, partly explaining the higher incidence in developmental and behavioral deficits in these individuals. Here, we investigated whether mitochondrial outcomes and metabolites from 22qDS children segregated with the altered dosage of one or several of these mitochondrial genes contributing to 22qDS etiology and/or morbidity. Plasma metabolomics, lymphocytic mitochondrial outcomes, and epigenetics (histone H3 Lys-4 trimethylation and 5-methylcytosine) were evaluated in samples from 11 22qDS children and 13 age- and sex-matched neurotypically developing controls. Metabolite differences between 22qDS children and controls reflected a shift from oxidative phosphorylation to glycolysis (higher lactate/pyruvate ratios) accompanied by an increase in reductive carboxylation of α-ketoglutarate (increased concentrations of 2-hydroxyglutaric acid, cholesterol, and fatty acids). Altered metabolism in 22qDS reflected a critical role for the haploinsufficiency of the mitochondrial citrate transporter SLC25A1, further enhanced by HIF-1α, MYC, and metabolite controls. This comprehensive profiling served to clarify the biochemistry of this disease underlying its broad, complex phenotype.
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Affiliation(s)
- Eleonora Napoli
- From the Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, California 95616
| | - Flora Tassone
- the Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, the Department of Biochemistry and Molecular Medicine, School of Medicine, UC Davis, Sacramento, California 95817
| | - Sarah Wong
- From the Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, California 95616
| | - Kathleen Angkustsiri
- the Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, the Department of Pediatrics, and
| | - Tony J Simon
- the Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, the Department of Psychiatry, UC Davis Medical Center, Sacramento, California 95817, and
| | - Gyu Song
- From the Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, California 95616
| | - Cecilia Giulivi
- From the Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, California 95616, the Medical Investigations of Neurodevelopmental Disorders (MIND) Institute,
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Rzem R, Achouri Y, Marbaix E, Schakman O, Wiame E, Marie S, Gailly P, Vincent MF, Veiga-da-Cunha M, Van Schaftingen E. A mouse model of L-2-hydroxyglutaric aciduria, a disorder of metabolite repair. PLoS One 2015; 10:e0119540. [PMID: 25763823 PMCID: PMC4357467 DOI: 10.1371/journal.pone.0119540] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/14/2015] [Indexed: 12/01/2022] Open
Abstract
The purpose of the present work was to progress in our understanding of the pathophysiology of L-2-hydroxyglutaric aciduria, due to a defect in L-2-hydroxyglutarate dehydrogenase, by creating and studying a mouse model of this disease. L-2-hydroxyglutarate dehydrogenase-deficient mice (l2hgdh-/-) accumulated L-2-hydroxyglutarate in tissues, most particularly in brain and testis, where the concentration reached ≈ 3.5 μmol/g. Male mice showed a 30% higher excretion of L-2-hydroxyglutarate compared to female mice, supporting that this dicarboxylic acid is partially made in males by lactate dehydrogenase C, a poorly specific form of this enzyme exclusively expressed in testes. Involvement of mitochondrial malate dehydrogenase in the formation of L-2-hydroxyglutarate was supported by the commensurate decrease in the formation of this dicarboxylic acid when down-regulating this enzyme in mouse l2hgdh-/- embryonic fibroblasts. The concentration of lysine and arginine was markedly increased in the brain of l2hgdh-/- adult mice. Saccharopine was depleted and glutamine was decreased by ≈ 40%. Lysine-α-ketoglutarate reductase, which converts lysine to saccharopine, was inhibited by L-2-hydroxyglutarate with a Ki of ≈ 0.8 mM. As low but significant activities of the bifunctional enzyme lysine-α-ketoglutarate reductase/saccharopine dehydrogenase were found in brain, these findings suggest that the classical lysine degradation pathway also operates in brain and is inhibited by the high concentrations of L-2-hydroxyglutarate found in l2hgdh-/- mice. Pathological analysis of the brain showed significant spongiosis. The vacuolar lesions mostly affected oligodendrocytes and myelin sheats, as in other dicarboxylic acidurias, suggesting that the pathophysiology of this model of leukodystrophy may involve irreversible pumping of a dicarboxylate in oligodendrocytes. Neurobehavioral testing indicated that the mice mostly suffered from a deficit in learning capacity. In conclusion, the findings support the concept that L-2-hydroxyglutaric aciduria is a disorder of metabolite repair. The accumulation of L-2-hydroxyglutarate exerts toxic effects through various means including enzyme inhibition and glial cell swelling.
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Affiliation(s)
- Rim Rzem
- Welbio and Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Younes Achouri
- Welbio and Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Etienne Marbaix
- Cell Unit, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Schakman
- Laboratory of Cell Physiology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Elsa Wiame
- Welbio and Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Sandrine Marie
- Laboratory of Metabolic Diseases, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Philippe Gailly
- Laboratory of Cell Physiology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Marie-Françoise Vincent
- Laboratory of Metabolic Diseases, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Maria Veiga-da-Cunha
- Welbio and Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Emile Van Schaftingen
- Welbio and Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
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Autophagy and oxidative stress in gliomas with IDH1 mutations. Acta Neuropathol 2014; 127:221-33. [PMID: 24150401 DOI: 10.1007/s00401-013-1194-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 09/27/2013] [Accepted: 10/04/2013] [Indexed: 12/20/2022]
Abstract
IDH1 mutations in gliomas associate with longer survival. Prooxidant and antiproliferative effects of IDH1 mutations and its D-2-hydroxyglutarate (2-HG) product have been described in vitro, but inconsistently observed. It is also unclear whether overexpression of mutant IDH1 in wild-type cells accurately phenocopies the effects of endogenous IDH1-mutations on tumor apoptosis and autophagy. Herein we investigated the effects of 2-HG and mutant IDH1 overexpression on proliferation, apoptosis, oxidative stress, and autophagy in IDH1 wild-type glioma cells, and compared those results with patient-derived tumors. 2-HG reduced viability and proliferation of U87MG and LN18 cells, triggered apoptosis in LN18 cells, and autophagy in U87MG cells. In vitro studies and flank xenografts of U87MG cells overexpressing R132H IDH1 exhibited increased oxidative stress, including increases of both manganese superoxide dismutase (MnSOD) and p62. Patient-derived IDH1-mutant tumors showed no significant differences in apoptosis or autophagy, but showed p62 accumulation and actually trended toward reduced MnSOD expression. These data indicate that mutant IDH1 and 2-HG can induce oxidative stress, autophagy, and apoptosis, but these effects vary greatly according to cell type.
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11
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Willmes DM, Birkenfeld AL. The Role of INDY in Metabolic Regulation. Comput Struct Biotechnol J 2013; 6:e201303020. [PMID: 24688728 PMCID: PMC3962103 DOI: 10.5936/csbj.201303020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/02/2013] [Accepted: 12/02/2013] [Indexed: 01/20/2023] Open
Abstract
Reduced expression of the Indy (I'm Not Dead Yet) gene in D. melanogaster and C. elegans extends longevity. Indy and its mammalian homolog mINDY (Slc13a5, NaCT) are transporters of TCA cycle intermediates, mainly handling the uptake of citrate via the plasma membrane into the cytosol. Deletion of mINDY in mice leads to significant metabolic changes akin to caloric restriction, likely caused by reducing the effects of mINDY-imported citrate on fatty acid and cholesterol synthesis, glucose metabolism and ß-oxidation. This review will provide an overview on different mammalian SLC1 3 family members with a focus on mINDY (SLCl3A5) in glucose and energy metabolism and will highlight the role of mINDY as a putative therapeutic target for the treatment of obesity, non-alcoholic fatty liver disease and type 2 diabetes.
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Affiliation(s)
- Diana M Willmes
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Andreas L Birkenfeld
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
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Sodium-coupled dicarboxylate and citrate transporters from the SLC13 family. Pflugers Arch 2013; 466:119-30. [PMID: 24114175 DOI: 10.1007/s00424-013-1369-y] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/19/2013] [Accepted: 09/23/2013] [Indexed: 12/30/2022]
Abstract
The SLC13 family in humans and other mammals consists of sodium-coupled transporters for anionic substrates: three transporters for dicarboxylates/citrate and two transporters for sulfate. This review will focus on the di- and tricarboxylate transporters: NaDC1 (SLC13A2), NaDC3 (SLC13A3), and NaCT (SLC13A5). The substrates of these transporters are metabolic intermediates of the citric acid cycle, including citrate, succinate, and α-ketoglutarate, which can exert signaling effects through specific receptors or can affect metabolic enzymes directly. The SLC13 transporters are important for regulating plasma, urinary and tissue levels of these metabolites. NaDC1, primarily found on the apical membranes of renal proximal tubule and small intestinal cells, is involved in regulating urinary levels of citrate and plays a role in kidney stone development. NaDC3 has a wider tissue distribution and high substrate affinity compared with NaDC1. NaDC3 participates in drug and xenobiotic excretion through interactions with organic anion transporters. NaCT is primarily a citrate transporter located in the liver and brain, and its activity may regulate metabolic processes. The recent crystal structure of the Vibrio cholerae homolog, VcINDY, provides a new framework for understanding the mechanism of transport in this family. This review summarizes current knowledge of the structure, function, and regulation of the di- and tricarboxylate transporters of the SLC13 family.
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Horbinski C. What do we know about IDH1/2 mutations so far, and how do we use it? Acta Neuropathol 2013; 125:621-36. [PMID: 23512379 DOI: 10.1007/s00401-013-1106-9] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/09/2013] [Indexed: 12/16/2022]
Abstract
Whole genome analyses have facilitated the discovery of clinically relevant genetic alterations in a variety of diseases, most notably cancer. A prominent example of this was the discovery of mutations in isocitrate dehydrogenases 1 and 2 (IDH1/2) in a sizeable proportion of gliomas and some other neoplasms. Herein the normal functions of these enzymes, how the mutations alter their catalytic properties, the effects of their D-2-hydroxyglutarate metabolite, technical considerations in diagnostic neuropathology, implications about prognosis and therapeutic considerations, and practical applications and controversies regarding IDH1/2 mutation testing are discussed.
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Affiliation(s)
- Craig Horbinski
- Department of Pathology, University of Kentucky, 307 Combs Cancer Research Facility, 800 Rose Street, Lexington, KY 40536, USA.
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Bergeron M, Clémençon B, Hediger M, Markovich D. SLC13 family of Na+-coupled di- and tri-carboxylate/sulfate transporters. Mol Aspects Med 2013; 34:299-312. [DOI: 10.1016/j.mam.2012.12.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/16/2012] [Indexed: 12/22/2022]
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