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Jimenez-Blasco D, Agulla J, Lapresa R, Garcia-Macia M, Bobo-Jimenez V, Garcia-Rodriguez D, Manjarres-Raza I, Fernandez E, Jeanson Y, Khoury S, Portais JC, Padro D, Ramos-Cabrer P, Carmeliet P, Almeida A, Bolaños JP. Weak neuronal glycolysis sustains cognition and organismal fitness. Nat Metab 2024; 6:1253-1267. [PMID: 38789798 PMCID: PMC11272580 DOI: 10.1038/s42255-024-01049-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 04/15/2024] [Indexed: 05/26/2024]
Abstract
The energy cost of neuronal activity is mainly sustained by glucose1,2. However, in an apparent paradox, neurons modestly metabolize glucose through glycolysis3-6, a circumstance that can be accounted for by the constant degradation of 6-phosphofructo-2-kinase-fructose-2,6-bisphosphatase-3 (PFKFB3)3,7,8, a key glycolysis-promoting enzyme. To evaluate the in vivo physiological importance of this hypoglycolytic metabolism, here we genetically engineered mice with their neurons transformed into active glycolytic cells through Pfkfb3 expression. In vivo molecular, biochemical and metabolic flux analyses of these neurons revealed an accumulation of anomalous mitochondria, complex I disassembly, bioenergetic deficiency and mitochondrial redox stress. Notably, glycolysis-mediated nicotinamide adenine dinucleotide (NAD+) reduction impaired sirtuin-dependent autophagy. Furthermore, these mice displayed cognitive decline and a metabolic syndrome that was mimicked by confining Pfkfb3 expression to hypothalamic neurons. Neuron-specific genetic ablation of mitochondrial redox stress or brain NAD+ restoration corrected these behavioural alterations. Thus, the weak glycolytic nature of neurons is required to sustain higher-order organismal functions.
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Affiliation(s)
- Daniel Jimenez-Blasco
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Jesús Agulla
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
| | - Rebeca Lapresa
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
| | - Marina Garcia-Macia
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Veronica Bobo-Jimenez
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
| | - Dario Garcia-Rodriguez
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Israel Manjarres-Raza
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Emilio Fernandez
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Yannick Jeanson
- RESTORE, University of Toulouse, Inserm U1031, CNRS 5070, UPS, EFS, Toulouse, France
| | - Spiro Khoury
- RESTORE, University of Toulouse, Inserm U1031, CNRS 5070, UPS, EFS, Toulouse, France
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, Toulouse, France
| | - Jean-Charles Portais
- RESTORE, University of Toulouse, Inserm U1031, CNRS 5070, UPS, EFS, Toulouse, France
- MetaboHUB-MetaToul, National Infrastructure of Metabolomics and Fluxomics, Toulouse, France
- Toulouse Biotechnology Institute, INSA de Toulouse INSA/CNRS 5504, UMR INSA/INRA 792, Toulouse, France
| | - Daniel Padro
- CIC biomaGUNE, Basque Research and Technology Alliance, Donostia-San Sebastián, Spain
| | - Pedro Ramos-Cabrer
- CIC biomaGUNE, Basque Research and Technology Alliance, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute (LKI), KU Leuven, VIB Center for Cancer Biology, VIB, Leuven, Belgium
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Angeles Almeida
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain
| | - Juan P Bolaños
- Institute of Functional Biology and Genomics, Universidad de Salamanca, CSIC, Salamanca, Spain.
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Universidad de Salamanca, CSIC, Salamanca, Spain.
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain.
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2
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Xu Y, Kusuyama J, Osana S, Matsuhashi S, Li L, Takada H, Inada H, Nagatomi R. Lactate promotes neuronal differentiation of SH-SY5Y cells by lactate-responsive gene sets through NDRG3-dependent and -independent manners. J Biol Chem 2023:104802. [PMID: 37172727 DOI: 10.1016/j.jbc.2023.104802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 04/23/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023] Open
Abstract
Lactate serves as the major glucose alternative to an energy substrate in the brain. Lactate level is increased in the fetal brain from the middle stage of gestation, indicating the involvement of lactate in brain development and neuronal differentiation. Recent reports show that lactate functions as a signaling molecule to regulate gene expression and protein stability. However, the roles of lactate signaling in neuronal cells remain unknown. Here, we showed that lactate promotes the all stages of neuronal differentiation of SH-SY5Y and Neuro2A, human and mouse neuroblastoma cell lines, characterized by increased neuronal marker expression and the rates of neurites extension. Transcriptomics revealed many lactate-responsive genes sets such as SPARCL1 in SH-SY5Y, Neuro2A, and primary embryonic mouse neuronal cells. The effects of lactate on neuronal function were mainly mediated through monocarboxylate transporters 1 (MCT1). We found that NDRG family member 3 (NDRG3), a lactate-binding protein, was highly expressed and stabilized by lactate treatment during neuronal differentiation. Combinative RNA-seq of SH-SY5Y with lactate treatment and NDRG3 knockdown shows that the promotive effects of lactate on neural differentiation are regulated through NDRG3-dependent and independent manners. Moreover, we identified TEA domain family member 1 (TEAD1) and ETS-related transcription factor 4 (ELF4) are the specific transcription factors that are regulated by both lactate and NDRG3 in neuronal differentiation. TEAD1 and ELF4 differently affect the expression of neuronal marker genes in SH-SY5Y cells. These results highlight the biological roles of extracellular and intracellular lactate as a critical signaling molecule that modifies neuronal differentiation.
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Affiliation(s)
- Yidan Xu
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Joji Kusuyama
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Department of Biosignals and Inheritance, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
| | - Shion Osana
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Graduate School of Informatics and Engineering, University of Electro-Communications
| | - Satayuki Matsuhashi
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
| | - Longfei Li
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hiroaki Takada
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
| | - Hitoshi Inada
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Department of Developmental Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryoichi Nagatomi
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.
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3
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Jeon YG, Kim YY, Lee G, Kim JB. Physiological and pathological roles of lipogenesis. Nat Metab 2023; 5:735-759. [PMID: 37142787 DOI: 10.1038/s42255-023-00786-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 03/15/2023] [Indexed: 05/06/2023]
Abstract
Lipids are essential metabolites, which function as energy sources, structural components and signalling mediators. Most cells are able to convert carbohydrates into fatty acids, which are often converted into neutral lipids for storage in the form of lipid droplets. Accumulating evidence suggests that lipogenesis plays a crucial role not only in metabolic tissues for systemic energy homoeostasis but also in immune and nervous systems for their proliferation, differentiation and even pathophysiological roles. Thus, excessive or insufficient lipogenesis is closely associated with aberrations in lipid homoeostasis, potentially leading to pathological consequences, such as dyslipidaemia, diabetes, fatty liver, autoimmune diseases, neurodegenerative diseases and cancers. For systemic energy homoeostasis, multiple enzymes involved in lipogenesis are tightly controlled by transcriptional and post-translational modifications. In this Review, we discuss recent findings regarding the regulatory mechanisms, physiological roles and pathological importance of lipogenesis in multiple tissues such as adipose tissue and the liver, as well as the immune and nervous systems. Furthermore, we briefly introduce the therapeutic implications of lipogenesis modulation.
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Affiliation(s)
- Yong Geun Jeon
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Ye Young Kim
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Gung Lee
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jae Bum Kim
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, South Korea.
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4
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Álvarez Z, Hyroššová P, Perales JC, Alcántara S. Neuronal Progenitor Maintenance Requires Lactate Metabolism and PEPCK-M-Directed Cataplerosis. Cereb Cortex 2014; 26:1046-58. [PMID: 25452568 DOI: 10.1093/cercor/bhu281] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
This study investigated the metabolic requirements for neuronal progenitor maintenance in vitro and in vivo by examining the metabolic adaptations that support neuronal progenitors and neural stem cells (NSCs) in their undifferentiated state. We demonstrate that neuronal progenitors are strictly dependent on lactate metabolism, while glucose induces their neuronal differentiation. Lactate signaling is not by itself capable of maintaining the progenitor phenotype. The consequences of lactate metabolism include increased mitochondrial and oxidative metabolism, with a strict reliance on cataplerosis through the mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) pathway to support anabolic functions, such as the production of extracellular matrix. In vivo, lactate maintains/induces populations of postnatal neuronal progenitors/NSCs in a PEPCK-M-dependent manner. Taken together, our data demonstrate that, lactate alone or together with other physical/biochemical cues maintain NSCs/progenitors with a metabolic signature that is classically found in tissues with high anabolic capacity.
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Affiliation(s)
- Zaida Álvarez
- Institute for Bioengineering of Catalonia-IBEC, Barcelona, Spain Department of Pathology and Experimental Therapeutics CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain
| | - Petra Hyroššová
- Department of Physiological Sciences II, Medical School (Bellvitge Campus), University of Barcelona-UB, Barcelona, Spain
| | - José Carlos Perales
- Department of Physiological Sciences II, Medical School (Bellvitge Campus), University of Barcelona-UB, Barcelona, Spain
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5
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Experimental evidence of metabolic disturbance in the white shrimp Penaeus vannamei induced by the Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV). J Invertebr Pathol 2012; 111:60-7. [DOI: 10.1016/j.jip.2012.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 11/19/2022]
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6
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Medina JM, Tabernero A. Lactate utilization by brain cells and its role in CNS development. J Neurosci Res 2005; 79:2-10. [PMID: 15573408 DOI: 10.1002/jnr.20336] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We studied the role played by lactate as an important substrate for the brain during the perinatal period. Under these circumstances, lactate is the main substrate for brain development and is used as a source of energy and carbon skeletons. In fact, lactate is used actively by brain cells in culture. Neurons, astrocytes, and oligodendrocytes use lactate as a preferential substrate for both energy purposes and as precursor of lipids. Astrocytes use lactate and other metabolic substrates for the synthesis of oleic acid, a new neurotrophic factor. Oligodendrocytes mainly use lactate as precursor of lipids, presumably those used to synthesize myelin. Neurons use lactate as a source of energy and as precursor of lipids. During the perinatal period, neurons may use blood lactate directly to meet the need for the energy and carbon skeletons required for proliferation and differentiation. During adult life, however, the lactate used by neurons may come from astrocytes, in which lactate is the final product of glycogen breakdown. It may be concluded that lactate plays an important role in brain development.
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Affiliation(s)
- José M Medina
- Department of Biochemistry and Molecular Biology, INCYL, University of Salamanca, Plaza de los Doctores de la Reina s/n, 37007 Salamanca, Spain.
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7
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Tabernero A, Lavado EM, Granda B, Velasco A, Medina JM. Neuronal differentiation is triggered by oleic acid synthesized and released by astrocytes. J Neurochem 2001; 79:606-16. [PMID: 11701764 DOI: 10.1046/j.1471-4159.2001.00598.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Unlike in the adult brain, the newborn brain specifically takes up serum albumin during the postnatal period, coinciding with the stage of maximal brain development. Here we report that albumin stimulates oleic acid synthesis by astrocytes from the main metabolic substrates available during brain development. Oleic acid released by astrocytes is used by neurons for the synthesis of phospholipids and is specifically incorporated into growth cones. Oleic acid promotes axonal growth, neuronal clustering, and expression of the axonal growth-associated protein-43, GAP-43; all these observations indicating neuronal differentiation. The effect of oleic acid on GAP-43 synthesis is brought about by the activation of protein kinase C, since it was prevented by inhibitors of this kinase, such as H-7, polymyxin or sphingosine. The expression of GAP-43 was significantly increased in neurons co-cultured with astrocytes by the presence of albumin indicating that neuronal differentiation takes place in the presence of oleic acid synthesized and released by astrocytes in situ. In conclusion, during brain development the presence of albumin could play an important role by triggering the synthesis and release of oleic acid by astrocytes, which induces neuronal differentiation.
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Affiliation(s)
- A Tabernero
- Unidad de Investigación, Hospital Universitario de Salamanca, Spain
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8
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The Dorothy Russell Havemeyer Foundation Third International Workshop on Equine Perinatology: comparative aspects. Proceedings. Equine Vet J 1998; 30:455-66. [PMID: 9844963 DOI: 10.1111/j.2042-3306.1998.tb04520.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Abstract
Maturation of the CNS in neonatal animals is dependent upon both sensory input and the constant availability of metabolic fuel. Previous reports indicate that the preferred metabolic substrate for the developing rat brain is lactate. In this study, we used the neonatal Sprague-Dawley rat to investigate a possible interactive role between touch and the regulation of serum lactate. Two hundred and fifty rats (postnatal d 0-7) were exposed to a standard tactile stimulation (TS) regimen to mimic nonspecific maternal stimulation. This regimen consisted of stroking the dorsum with a soft camel hair brush for 30 s every minute for 10 min. Serum lactate and glucose levels were measured after TS. In newborn (d 0) rats, lactate levels were increased by 207% in stroked pups versus controls. This elevation of serum lactate persisted for 30 min after cessation of TS. On d 7, TS increased lactate only 11%. Glucose levels were unaffected at all ages. In neonatal pups, pretreatment with pentobarbital blocked the effect of TS, whereas epidermal growth factor evoked a synergistic response. Capsaicin pretreatment had no effect. Mixed arteriovenous blood gases revealed a mild increase in pH and a decrease in Pco2 after TS. We conclude that TS in newborn rats is a regulator of circulating lactate. This response is maximal in the immediate postnatal period and wanes over the 1st wk of life. We speculate that the transduction of sensory signals by the skin is a mechanism regulating the availability of cerebral energy substrates in the newborn mammal.
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Affiliation(s)
- M M Alasmi
- Division of Neonatology, Children's Hospital Medical Center, University of Cincinnati, Ohio 45267, USA
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10
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Abstract
The effects of valproate on brain energy and lipid metabolism is reviewed. Increasing evidence suggests that valproate uses the monocarboxylic acid carrier in order to cross the blood brain barrier (BBB) and the neural cell plasma membranes. The uptake of valproate into the brain through this mechanism would compete with the uptake of energy precursors, such as the monocarboxylic acids 3-hydroxybutyrate, lactate or pyruvate and with some amino acids, but not with glucose. This could impair brain fuel utilization, specially during the neonatal period or childhood, when lactate or 3-hydroxybutyrate furnishes alternative substrates to glucose for the brain. It is concluded that valproate interference with energy metabolism may have implications for the therapeutic action of the drug, stressing the possibility that valproate-mediated alterations in brain lipid synthesis may contribute to the pharmacological action of the drug.
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Affiliation(s)
- J P Bolaños
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia,Universidad de Salamanca, Spain
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11
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Almeida A, González-Buitrago JM, Bolaños JP, Medina JM. Fuel utilization by early newborn brain is preserved under congenital hypothyroidism in the rat. Pediatr Res 1996; 40:410-4. [PMID: 8865277 DOI: 10.1203/00006450-199609000-00008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mental retardation associated with hypothyroidism may be caused by impairment of brain ketone body-metabolizing enzymes during the suckling period. However, much evidence suggests that, immediately after delivery, lactate, instead of ketone bodies or glucose, may be the best substrate for the brain. In this work, we have studied the effect of experimentally induced congenital hypothyroidism on the rate of lactate, glucose, and 3-hydroxybutyrate utilization in early neonatal brain slices. Methimazole (MMI) administration to the mothers caused a 5.4- and 1.7-fold decrease in neonatal plasma concentrations of L-thyroxine (T4) and 3,5,3'-triiodo-L-thyronine (T3), respectively. Propylthiouracil (PTU) administration to the mothers caused a 7.3- and > 2-fold decrease in plasma T4 and T3 concentrations, respectively. MMI-induced hypothyroidism did not significantly modify the rate of lactate, glucose, or 3-hydroxybutyrate oxidation to CO2 and their incorporation into lipids by the neonatal brain. However, PTU-induced hypothyroidism decreased the rate of lactate and glucose oxidation to CO2 and their incorporation into lipids by 17% (p < 0.05). 3-Hydroxybutyrate utilization was not modified by this treatment. Separation by HPLC of the lipids revealed that PTU-mediated inhibition of lipid synthesis from lactate and glucose may be accounted for by specific inhibition of the rate of sterol synthesis (15%, p < 0.05), whereas the rate of phospholipid synthesis was unaffected. These results suggest that the early newborn may develop mechanisms aimed at avoiding the possible brain damage caused by the inhibition of lipid synthesis brought about by mild neonatal hypothyroidism.
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Affiliation(s)
- A Almeida
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Salamanca, Spain
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12
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Medina JM, Tabernero A, Tovar JA, Martín-Barrientos J. Metabolic fuel utilization and pyruvate oxidation during the postnatal period. J Inherit Metab Dis 1996; 19:432-42. [PMID: 8884567 DOI: 10.1007/bf01799104] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The transplacental supply of nutrients is interrupted at birth, which diverts maternal metabolism to lactation. After birth, energy homeostasis is rapidly regained through milk nutrients which supply the newborn with the fatty acids and ketone bodies required for neonatal development. However, immediately after birth and before the onset of suckling there is a time lapse in which the newborn undergoes a unique kind of starvation. During this period glucose is scarce and ketone bodies are not available owing to the delay in ketogenesis. Under these circumstances, the newborn is supplied with another metabolic fuel, lactate, which is utilized as a source of energy and carbon skeletons. Neonatal rat lung, heart, liver and brain utilize lactate for energy production and lipogenesis. Lactate is also utilized by the brain of human babies with type I glycogenosis. Both rat neurons and astrocytes in primary culture actively use lactate as an oxidizable substrate and as a precursor of phospholipids and sterols. Lactate oxidation is enhanced by dichloroacetate, an inhibitor of the pyruvate dehydrogenase kinase in neurons but not in astrocytes, suggesting that the pyruvate dehydrogenase is regulated differently in each type of cell. Despite the low activity of this enzyme in newborn brain, pyruvate decarboxylation is the main fate of glucose in both neurons and astrocytes. The occurrence of a yeast-like pyruvate decarboxylase activity in neonatal brain may explain these results.
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Affiliation(s)
- J M Medina
- Departmento de Bioquímica Biología Molecular, Facultad de Farmacia, Universidad de Salamanca, Spain
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13
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Bolaños JP, Medina JM. Inhibition of neonatal brain fuel utilization by valproate and E-delta 2-valproate is not a consequence of the stimulation of the gamma-aminobutyric acid shunt. Life Sci 1994; 55:PL397-402. [PMID: 7968221 DOI: 10.1016/0024-3205(94)00323-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Stimulation of the gamma-aminobutyric acid (GABA) shunt by valproate and its major metabolite, E-delta 2-valproate, has been proposed to decrease brain energy metabolism. In order to elucidate this hypothesis, the effect of these drugs on substrate utilization in neonatal rat brain slices was studied. The overall rate of lactate utilization was dose-dependently inhibited by both drugs. Valproate and E-delta 2-valproate inhibited both sterol and fatty acid syntheses from 3-hydroxybutyrate. The rate of glucose utilization was not affected by valproate nor E-delta 2-valproate. The inhibition of the GABA aminotransferase by aminooxyacetate decreased lipogenesis from lactate, 3-hydroxybutyrate and glucose. The inhibitor of the mitochondrial pyruvate carrier, alpha-cyano-4-hydroxycinnamate, strongly decreased the rate of lactate, 3-hydroxybutyrate and glucose utilization, suggesting that the inhibition of pyruvate mitochondrial carrier is not the mode of action of these drugs. It is suggested that inhibition of plasma membrane monocarboxylate carrier by valproate and E-delta 2-valproate, but not the activation of the GABA shunt, is responsible for the inhibition of the brain fuel utilization.
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Affiliation(s)
- J P Bolaños
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Spain
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14
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Tabernero A, Bolaños JP, Medina JM. Lipogenesis from lactate in rat neurons and astrocytes in primary culture. Biochem J 1993; 294 ( Pt 3):635-8. [PMID: 8379917 PMCID: PMC1134508 DOI: 10.1042/bj2940635] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The rate of synthesis of phospholipid and sterol species from L-lactate in neurons and astrocytes in primary culture was studied. Both types of cells actively utilized lactate as lipid precursor, although the rate of lipogenesis was about 2-fold greater in astrocytes than in neurons. The incorporation of lactate into phospholipids was significantly higher than that into sterols in both types of cells, but the ratio of phospholipid/sterol synthesis was much higher in astrocytes than in neurons. Phosphatidylcholine (PC) was the main phospholipid synthesized in both types of cells, followed by phosphatidylethanolamine (PE), phosphatidylserine and phosphatidylinositol. No detectable synthesis of sphingomyelins was observed. The ratio of PC/PE synthesis was about 2-fold higher in astrocytes than in neurons. The main sterol synthesized in neurons was lanosterol, followed by desmosterol. However, the main sterol synthesized in astrocytes was desmosterol, followed by lanosterol and cholesterol. The different ratios of phospholipid/sterol and PC/PE synthesis found in neurons and astrocytes may result in different membrane fluidity being higher in astrocytes than in neurons. This may be associated with differences in the functionality of both types of cells.
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Affiliation(s)
- A Tabernero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Salamanca, Spain
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