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Pandya VA, Patani R. The role of glial cells in amyotrophic lateral sclerosis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:381-450. [PMID: 38802179 DOI: 10.1016/bs.irn.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) has traditionally been considered a neuron-centric disease. This view is now outdated, with increasing recognition of cell autonomous and non-cell autonomous contributions of central and peripheral nervous system glia to ALS pathomechanisms. With glial research rapidly accelerating, we comprehensively interrogate the roles of astrocytes, microglia, oligodendrocytes, ependymal cells, Schwann cells and satellite glia in nervous system physiology and ALS-associated pathology. Moreover, we highlight the inter-glial, glial-neuronal and inter-system polylogue which constitutes the healthy nervous system and destabilises in disease. We also propose classification based on function for complex glial reactive phenotypes and discuss the pre-requisite for integrative modelling to advance translation. Given the paucity of life-enhancing therapies currently available for ALS patients, we discuss the promising potential of harnessing glia in driving ALS therapeutic discovery.
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Affiliation(s)
- Virenkumar A Pandya
- University College London Medical School, London, United Kingdom; The Francis Crick Institute, London, United Kingdom.
| | - Rickie Patani
- The Francis Crick Institute, London, United Kingdom; Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology, Queen Square, London, United Kingdom.
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Ye J, Yan X, Zhang W, Lu J, Xu S, Li X, Qin P, Gong X, Liu Y, Ling Y, Li Y, Zhang Y, Fang F. Integrative proteomic and phosphoproteomic analysis in the female goat hypothalamus to study the onset of puberty. BMC Genomics 2023; 24:621. [PMID: 37853328 PMCID: PMC10583467 DOI: 10.1186/s12864-023-09705-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 09/28/2023] [Indexed: 10/20/2023] Open
Abstract
BACKGROUND Puberty marks the end of childhood and achieve sexual maturation and fertility. The role of hypothalamic proteins in regulating puberty onset is unclear. We performed a comprehensive differential proteomics and phosphoproteomics analysis in prepubertal and pubertal goats to determine the roles of hypothalamic proteins and phosphoproteins during the onset of puberty. RESULTS We used peptide and posttranslational modifications peptide quantification and statistical analyses, and identified 69 differentially expressed proteins from 5,057 proteins and 576 differentially expressed phosphopeptides from 1574 phosphorylated proteins. Combined proteomic and phosphoproteomics, 759 correlated proteins were identified, of which 5 were differentially expressed only at the protein level, and 201 were only differentially expressed at the phosphoprotein level. Pathway enrichment analyses revealed that the majority of correlated proteins were associated with glycolysis/gluconeogenesis, Fc gamma R-mediated phagocytosis, focal adhesion, GABAergic synapse, and Rap1 signaling pathway. These pathways are related to cell proliferation, neurocyte migration, and promoting the release of gonadotropin-releasing hormone in the hypothalamus. CTNNB1 occupied important locations in the protein-protein interaction network and is involved in focal adhesion. CONCLUSION The results demonstrate that the proteins differentially expression only at the protein level or only differentially expressed at the phosphoprotein level and their related signalling pathways are crucial in regulating puberty in goats. These differentially expressed proteins and phosphorylated proteins may constitute the proteomic backgrounds between the two different stages.
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Affiliation(s)
- Jing Ye
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Xu Yan
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Wei Zhang
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
| | - Juntai Lu
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
| | - Shuangshuang Xu
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
| | - Xiaoqian Li
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
| | - Ping Qin
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Xinbao Gong
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Ya Liu
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Yinghui Ling
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Yunsheng Li
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Yunhai Zhang
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Fugui Fang
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, 130 Changjiang West Road, 230036, Hefei, Anhui, China.
- Anhui Province Key Laboratory of Local Livestock and Poultry, Genetical Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, 230036, Hefei, Anhui, China.
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Fonseca-Barriendos D, Castañeda-Cabral JL, Martínez-Cuevas F, Besio W, Valdés-Cruz A, Rocha L. Transcranial Focal Electric Stimulation Avoids P-Glycoprotein Over-Expression during Electrical Amygdala Kindling and Delays Epileptogenesis in Rats. Life (Basel) 2023; 13:1294. [PMID: 37374077 DOI: 10.3390/life13061294] [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: 04/13/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Recent evidence suggests that P-glycoprotein (P-gp) overexpression mediates hyperexcitability and is associated with epileptogenesis. Transcranial focal electrical stimulation (TFS) delays epileptogenesis and inhibits P-gp overexpression after a generalized seizure. Here, first we measured P-gp expression during epileptogenesis and second, we assessed if TFS antiepileptogenic effect was related with P-gp overexpression avoidance. Male Wistar rats were implanted in right basolateral amygdala and stimulated daily for electrical amygdala kindling (EAK), P-gp expression was assessed during epileptogenesis in relevant brain areas. Stage I group showed 85% increase in P-gp in ipsilateral hippocampus (p < 0.001). Stage III group presented 58% and 57% increase in P-gp in both hippocampi (p < 0.05). Kindled group had 92% and 90% increase in P-gp in both hippocampi (p < 0.01), and 93% and 143% increase in both neocortices (p < 0.01). For the second experiment, TFS was administrated daily after each EAK stimulation for 20 days and P-gp concentration was assessed. No changes were found in the TFS group (p > 0.05). Kindled group showed 132% and 138% increase in P-gp in both hippocampi (p < 0.001) and 51% and 92% increase in both cortices (p < 0.001). Kindled + TFS group presented no changes (p > 0.05). Our experiments revealed that progression of EAK is associated with increased P-gp expression. These changes are structure-specific and dependent on seizure severity. EAK-induced P-gp overexpression would be associated with neuronal hyperexcitability and thus, epileptogenesis. P-gp could be a novel therapeutical target to avoid epileptogenesis. In accordance with this, TFS inhibited P-gp overexpression and interfered with EAK. An important limitation of the present study is that P-gp neuronal expression was not evaluated under the different experimental conditions. Future studies should be carried out to determine P-gp neuronal overexpression in hyperexcitable networks during epileptogenesis. The TFS-induced lessening of P-gp overexpression could be a novel therapeutical strategy to avoid epileptogenesis in high-risk patients.
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Affiliation(s)
- Daniel Fonseca-Barriendos
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Ciudad de México C.P. 14330, Mexico
| | - José Luis Castañeda-Cabral
- Departamento de Biología Celular y Molecular, Centro Universitrio de Ciencias Biológicas y Agropecuaias, Universidad de Guadalajara, Zapopan C.P. 44600, Mexico
| | - Frida Martínez-Cuevas
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Ciudad de México C.P. 14330, Mexico
| | - Walter Besio
- Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, RI 028881, USA
| | - Alejandro Valdés-Cruz
- Laboratorio de Neurofisiología del Control y la Regulación, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Ciudad de México C.P. 14370, Mexico
| | - Luisa Rocha
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Ciudad de México C.P. 14330, Mexico
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Duran J. Role of Astrocytes in the Pathophysiology of Lafora Disease and Other Glycogen Storage Disorders. Cells 2023; 12:cells12050722. [PMID: 36899857 PMCID: PMC10000527 DOI: 10.3390/cells12050722] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/05/2023] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
Lafora disease is a rare disorder caused by loss of function mutations in either the EPM2A or NHLRC1 gene. The initial symptoms of this condition are most commonly epileptic seizures, but the disease progresses rapidly with dementia, neuropsychiatric symptoms, and cognitive deterioration and has a fatal outcome within 5-10 years after onset. The hallmark of the disease is the accumulation of poorly branched glycogen in the form of aggregates known as Lafora bodies in the brain and other tissues. Several reports have demonstrated that the accumulation of this abnormal glycogen underlies all the pathologic traits of the disease. For decades, Lafora bodies were thought to accumulate exclusively in neurons. However, it was recently identified that most of these glycogen aggregates are present in astrocytes. Importantly, astrocytic Lafora bodies have been shown to contribute to pathology in Lafora disease. These results identify a primary role of astrocytes in the pathophysiology of Lafora disease and have important implications for other conditions in which glycogen abnormally accumulates in astrocytes, such as Adult Polyglucosan Body disease and the buildup of Corpora amylacea in aged brains.
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Affiliation(s)
- Jordi Duran
- Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), 08017 Barcelona, Spain;
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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5
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Pasula MB, Napit PR, Alhamyani A, Roy SC, Sylvester PW, Bheemanapally K, Briski KP. Sex Dimorphic Glucose Transporter-2 Regulation of Hypothalamic Astrocyte Glucose and Energy Sensor Expression and Glycogen Metabolism. Neurochem Res 2023; 48:404-417. [PMID: 36173588 PMCID: PMC9898103 DOI: 10.1007/s11064-022-03757-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/17/2022] [Accepted: 09/06/2022] [Indexed: 02/06/2023]
Abstract
The plasma membrane glucose transporter-2 (GLUT2) monitors brain cell uptake of the critical nutrient glucose, and functions within astrocytes of as-yet-unknown location to control glucose counter-regulation. Hypothalamic astrocyte-neuron metabolic coupling provides vital cues to the neural glucostatic network. Current research utilized an established hypothalamic primary astrocyte culture model along with gene knockdown tools to investigate whether GLUT2 imposes sex-specific regulation of glucose/energy sensor function and glycogen metabolism in this cell population. Data show that GLUT2 stimulates or inhibits glucokinase (GCK) expression in glucose-supplied versus -deprived male astrocytes, but does not control this protein in female. Astrocyte 5'-AMP-activated protein kinaseα1/2 (AMPK) protein is augmented by GLUT2 in each sex, but phosphoAMPKα1/2 is coincidently up- (male) or down- (female) regulated. GLUT2 effects on glycogen synthase (GS) diverges in the two sexes, but direction of this control is reversed by glucoprivation in each sex. GLUT2 increases (male) or decreases (female) glycogen phosphorylase-brain type (GPbb) protein during glucoprivation, yet simultaneously inhibits (male) or stimulates (female) GP-muscle type (GPmm) expression. Astrocyte glycogen accumulation is restrained by GLUT2 when glucose is present (male) or absent (both sexes). Outcomes disclose sex-dependent GLUT2 control of the astrocyte glycolytic pathway sensor GCK. Data show that glucose status determines GLUT2 regulation of GS (both sexes), GPbb (female), and GPmm (male), and that GLUT2 imposes opposite control of GS, GPbb, and GPmm profiles between sexes during glucoprivation. Ongoing studies aim to investigate molecular mechanisms underlying sex-dimorphic GLUT2 regulation of hypothalamic astrocyte metabolic-sensory and glycogen metabolic proteins, and to characterize effects of sex-specific astrocyte target protein responses to GLUT2 on glucose regulation.
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Affiliation(s)
- Madhu Babu Pasula
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Prabhat R Napit
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Abdulrahman Alhamyani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Sagor C Roy
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Paul W Sylvester
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building 1800 Bienville Drive, 71201, Monroe, LA, USA.
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Sex-Dimorphic Glucocorticoid Receptor Regulation of Hypothalamic Primary Astrocyte Glycogen Metabolism: Interaction with Norepinephrine. NEUROGLIA (BASEL, SWITZERLAND) 2022; 3:144-157. [PMID: 36685006 PMCID: PMC9850496 DOI: 10.3390/neuroglia3040010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Astrocyte glycogen is a critical metabolic variable that impacts hypothalamic control of glucostasis. Glucocorticoid hormones regulate peripheral glycogen, but their effects on hypothalamic glycogen are not known. A hypothalamic astrocyte primary culture model was used to investigate the premise that glucocorticoids impose sex-dimorphic independent and interactive control of glycogen metabolic enzyme protein expression and glycogen accumulation. The glucocorticoid receptor (GR) agonist dexamethasone (DEX) down-regulated glycogen synthase (GS), glycogen phosphorylase (GP)-brain type (GPbb), and GP-muscle type (GPmm) proteins in glucose-supplied male astrocytes, but enhanced these profiles in female. The catecholamine neurotransmitter norepinephrine (NE) did not alter these proteins, but amplified DEX inhibition of GS and GPbb in male or abolished GR stimulation of GPmm in female. In both sexes, DEX and NE individually increased glycogen content, but DEX attenuated the magnitude of noradrenergic stimulation. Glucoprivation suppressed GS, GPbb, and GPmm in male, but not female astrocytes, and elevated or diminished glycogen in these sexes, respectively. Glucose-deprived astrocytes exhibit GR-dependent induced glycogen accumulation in both sexes, and corresponding loss (male) or attenuation (female) of noradrenergic-dependent glycogen build-up. Current evidence for GR augmentation of hypothalamic astrocyte glycogen content in each sex, yet divergent effects on glycogen enzyme proteins infers that glucocorticoids may elicit opposite adjustments in glycogen turnover in each sex. Results document GR modulation of NE stimulation of glycogen accumulation in the presence (male and female) or absence (female) of glucose. Outcomes provide novel proof that astrocyte energy status influences the magnitude of GR and NE signal effects on glycogen mass.
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He T, Yang GY, Zhang Z. Crosstalk of Astrocytes and Other Cells during Ischemic Stroke. LIFE (BASEL, SWITZERLAND) 2022; 12:life12060910. [PMID: 35743941 PMCID: PMC9228674 DOI: 10.3390/life12060910] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/04/2022] [Accepted: 06/07/2022] [Indexed: 12/27/2022]
Abstract
Stroke is a leading cause of death and long-term disability worldwide. Astrocytes structurally compose tripartite synapses, blood–brain barrier, and the neurovascular unit and perform multiple functions through cell-to-cell signaling of neurons, glial cells, and vasculature. The crosstalk of astrocytes and other cells is complicated and incompletely understood. Here we review the role of astrocytes in response to ischemic stroke, both beneficial and detrimental, from a cell–cell interaction perspective. Reactive astrocytes provide neuroprotection through antioxidation and antiexcitatory effects and metabolic support; they also contribute to neurorestoration involving neurogenesis, synaptogenesis, angiogenesis, and oligodendrogenesis by crosstalk with stem cells and cell lineage. In the meantime, reactive astrocytes also play a vital role in neuroinflammation and brain edema. Glial scar formation in the chronic phase hinders functional recovery. We further discuss astrocyte enriched microRNAs and exosomes in the regulation of ischemic stroke. In addition, the latest notion of reactive astrocyte subsets and astrocytic activity revealed by optogenetics is mentioned. This review discusses the current understanding of the intimate molecular conversation between astrocytes and other cells and outlines its potential implications after ischemic stroke. “Neurocentric” strategies may not be sufficient for neurological protection and recovery; future therapeutic strategies could target reactive astrocytes.
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Affiliation(s)
- Tingting He
- Department of Neurology, Shanghai Tenth People’s Hospital, Tongji University, Shanghai 200072, China;
- Neuroscience and Neuroengineering Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Guo-Yuan Yang
- Neuroscience and Neuroengineering Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
- Correspondence: (G.-Y.Y.); (Z.Z.); Tel.: +86-21-62933186 (G.-Y.Y.); Fax: +86-21-62932302 (G.-Y.Y.)
| | - Zhijun Zhang
- Neuroscience and Neuroengineering Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
- Correspondence: (G.-Y.Y.); (Z.Z.); Tel.: +86-21-62933186 (G.-Y.Y.); Fax: +86-21-62932302 (G.-Y.Y.)
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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Salman TM, Iyanda MA, Alli-Oluwafuyi AM, Sulaiman SO, Alagbonsi AI. Telfairia occidentalis stimulates hepatic glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms. Metabol Open 2021; 10:100092. [PMID: 33997754 PMCID: PMC8095178 DOI: 10.1016/j.metop.2021.100092] [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: 02/24/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 11/02/2022] Open
Abstract
Background Telfairia occidentalis (TO), a plant consumed for its nutritional and medicinal values, exhibits hypoglycaemic effect. However, the metabolic fate of the glucose following TO-induced insulin secretion and consequent hypoglycaemia is not clear. Objective This study determined the effect of ethyl acetate and n-hexane fractions of TO leaf extracts on some biochemical parameters in the glucose metabolic pathway to explain the possible fate of blood glucose following TO-induced hypoglycaemia. Methods Eighteen male Wistar rats (180-200 g) divided into control, n-hexane TO fraction- and ethyl acetate TO fraction-treated groups (n = 6/group) were used. The control animals received normal saline while the treated groups received TO at 100 mg/kg for seven days. After 24 h following the last dose, the animals were anaesthetised using ketamine; blood samples were collected and livers harvested to determine some biochemical parameters. Results Ethyl acetate TO fraction significantly increased plasma insulin, liver glucokinase activity and plasma pyruvate concentration, but significantly decreased plasma glucose and liver glycogen, without significant changes in plasma lactate, glucose-6-phosphate, liver glucose-6-phosphatase and lactate dehydrogenase activities when compared with control. N-hexane TO fraction significantly reduced liver glucose-6-phosphatase activity and glycogen but significantly increased plasma pyruvate, without significant changes in plasma glucose, insulin, glucose-6-phosphate and lactate concentrations; and liver glucokinase and lactate dehydrogenase activities. Conclusion The present study showed that insulin-mediated TO-induced hypoglycaemia resulted in the stimulation of glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms.
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Key Words
- ANOVA, Analysis of Variance
- ATP, Adenosine triphosphate
- EATO, Ethyl acetate TO fraction
- ELISA, Enzyme-linked immunosorbent assay
- G6P, Glucose-6-phosphate
- G6PD, Glucose-6-phosphate dehydrogenase
- G6Pase, Glucose-6-phosphatase
- GCK, Glucokinase
- GLUT, Glucose transporter
- GSIS, glucose-stimulated insulin secretion
- Glucoregulatory enzymes
- Glucose metabolites
- Glycogen
- HClO4, Perchloric acid
- HRP, Horseradish Peroxidase
- IMGU, Insulin-mediated glucose uptake
- Insulin
- KOH, Potassium hydroxide
- LDH, Lactate dehydrogenase
- MCT, Monocarboxylate transporters
- NAD, Nicotinamide adenine dinucleotide
- NHTO, N-hexane TO fraction
- Plasma glucose
- SEM, Standard error of mean
- TCA, Tricarboxylic acid cycle
- TO, Telfairia occidentalis
- Telfairia occidentalis
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Affiliation(s)
- Toyin Mohammed Salman
- Department of Physiology, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Mayowa Adewale Iyanda
- Department of Physiology, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | | | - Sheu Oluwadare Sulaiman
- Physiology Department, Kampala International University - Western Campus, Ishaka-Bushenyi, Uganda.,Department of Morphology (Cell Biology), Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Abdullateef Isiaka Alagbonsi
- Department of Clinical Biology (Physiology), School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Huye Campus, Rwanda
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Bheemanapally K, Ibrahim MMH, Briski KP. HPLC-electrospray ionization-mass spectrometry optimization by high-performance design of experiments for astrocyte glutamine measurement. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4680. [PMID: 33462970 PMCID: PMC7874509 DOI: 10.1002/jms.4680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/01/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
The amino acid glutamine (Gln) is a likely source of energy in the brain during neuroglucopenia. Effects of glucose deficiency on astrocyte Gln homeostasis remain unclear, as analytical tools of requisite sensitivity for quantification of intracellular levels of this molecule are not currently available. Here, a primary hypothalamic astrocyte culture model was used in conjunction with design of experiments (DOE)-refined high-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) methodology to investigate the hypothesis that glucoprivation alters astrocyte Gln content in a sex-specific manner. Critical mass spectrometric parameters for Gln derivative chromatographic response were identified by comparing the performance of central composite design, Box-Behnken design, and Optimal Design (OD)-A, -D, -I, -Distance, and -Modified Distance DOE models. The outcomes showed that the OD-A-generated response was superior relative to other design outcomes. Forecasted surface plot critical mass spectrometric parameters were maximized by OD-A, OD-Distance, and OD-Modified Distance designs. OD-A produced a high-performance method that yielded experimental run and forecasted surface plot maximal responses. Optimized mass spectrometric analysis of male versus female astrocyte Gln content provides novel evidence that glucoprivation significantly depletes this amino acid in female, but not in male, and that this sex-specific response may involve differential sensitivity to estrogen receptor signaling. This technological advance will facilitate efforts to ascertain how distinctive physiological and pathophysiological stimuli impact astrocyte Gln metabolism in each sex.
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Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
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11
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Briski KP, Ibrahim MMH, Mahmood ASMH, Alshamrani AA. Norepinephrine Regulation of Ventromedial Hypothalamic Nucleus Astrocyte Glycogen Metabolism. Int J Mol Sci 2021; 22:ijms22020759. [PMID: 33451134 PMCID: PMC7828624 DOI: 10.3390/ijms22020759] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/04/2021] [Accepted: 01/09/2021] [Indexed: 12/15/2022] Open
Abstract
The catecholamine norepinephrine (NE) links hindbrain metabolic-sensory neurons with key glucostatic control structures in the brain, including the ventromedial hypothalamic nucleus (VMN). In the brain, the glycogen reserve is maintained within the astrocyte cell compartment as an alternative energy source to blood-derived glucose. VMN astrocytes are direct targets for metabolic stimulus-driven noradrenergic signaling due to their adrenergic receptor expression (AR). The current review discusses recent affirmative evidence that neuro-metabolic stability in the VMN may be shaped by NE influence on astrocyte glycogen metabolism and glycogen-derived substrate fuel supply. Noradrenergic modulation of estrogen receptor (ER) control of VMN glycogen phosphorylase (GP) isoform expression supports the interaction of catecholamine and estradiol signals in shaping the physiological stimulus-specific control of astrocyte glycogen mobilization. Sex-dimorphic NE control of glycogen synthase and GP brain versus muscle type proteins may be due, in part, to the dissimilar noradrenergic governance of astrocyte AR and ER variant profiles in males versus females. Forthcoming advances in the understanding of the molecular mechanistic framework for catecholamine stimulus integration with other regulatory inputs to VMN astrocytes will undoubtedly reveal useful new molecular targets in each sex for glycogen mediated defense of neuronal metabolic equilibrium during neuro-glucopenia.
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12
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Ibrahim MMH, Bheemanapally K, Sylvester PW, Briski KP. Sex differences in glucoprivic regulation of glycogen metabolism in hypothalamic primary astrocyte cultures: Role of estrogen receptor signaling. Mol Cell Endocrinol 2020; 518:111000. [PMID: 32853745 PMCID: PMC7606756 DOI: 10.1016/j.mce.2020.111000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022]
Abstract
Hypoglycemia causes sex-reliant changes in hypothalamic astrocyte glycogen metabolism in vivo. The role of nuclear versus membrane astrocyte estrogen receptors (ER) in glucoprivic regulation of glycogen is unclear. Here, primary hypothalamic astrocyte cultures were treated with selective ER antagonists during glucoprivation to investigate the hypothesis that ER mediate sex-specific glycogen responses to glucoprivation. Results show that glucoprivic down-regulation of glycogen synthase expression is mediated by transmembrane G protein-coupled ER-1 (GPER) signaling in each sex and estrogen receptor (ER)-beta (ERβ) activity in females. Glucoprivic inhibition of glycogen phosphorylase involves GPER and ERβ in females, but ER-independent mechanisms in males. GPER, ERβ, and ER-alpha (ERα) inhibit or stimulate AMPK protein expression in male versus female astrocytes, respectively. Glucoprivic augmentation of phospho-AMPK profiles in male glia was opposed by GPER activation, whereas GPER and ERβ suppress this protein in females. Astrocyte ERα and GPER content was down-regulated in each sex during glucose deficiency, whereas ERβ levels was unaltered (males) or increased (females). Glucoprivation correspondingly elevated or diminished male versus female astrocyte glycogen content; ER antagonism reversed this response in males, but not females. Results identify distinctive ER variants involved in sex-similar versus sex-specific astrocyte protein responses to withdrawal of this substrate fuel. Notably, glucoprivation elicits a directional switch or gain-of-effect of GPER and ERβ on specific glial protein profiles. Outcomes infer that ERs are crucial for glucoprivic regulation of astrocyte glycogen accumulation in males. Alternatively, estradiol may act independently of ER signaling to disassemble this reserve in females.
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Affiliation(s)
- Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, 71201, USA
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, 71201, USA
| | - Paul W Sylvester
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, 71201, USA.
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13
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Powell CL, Davidson AR, Brown AM. Universal Glia to Neurone Lactate Transfer in the Nervous System: Physiological Functions and Pathological Consequences. BIOSENSORS-BASEL 2020; 10:bios10110183. [PMID: 33228235 PMCID: PMC7699491 DOI: 10.3390/bios10110183] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022]
Abstract
Whilst it is universally accepted that the energy support of the brain is glucose, the form in which the glucose is taken up by neurones is the topic of intense debate. In the last few decades, the concept of lactate shuttling between glial elements and neural elements has emerged in which the glial cells glycolytically metabolise glucose/glycogen to lactate, which is shuttled to the neural elements via the extracellular fluid. The process occurs during periods of compromised glucose availability where glycogen stored in astrocytes provides lactate to the neurones, and is an integral part of the formation of learning and memory where the energy intensive process of learning requires neuronal lactate uptake provided by astrocytes. More recently sleep, myelination and motor end plate integrity have been shown to involve lactate shuttling. The sequential aspect of lactate production in the astrocyte followed by transport to the neurones is vulnerable to interruption and it is reported that such disparate pathological conditions as Alzheimer's disease, amyotrophic lateral sclerosis, depression and schizophrenia show disrupted lactate signalling between glial cells and neurones.
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Affiliation(s)
- Carolyn L. Powell
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
| | - Anna R. Davidson
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
| | - Angus M. Brown
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
- Department of Neurology, University of Washington, Seattle, WA 98105, USA
- Correspondence:
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14
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Cell-specific metabolomic responses to injury: novel insights into blood-brain barrier modulation. Sci Rep 2020; 10:7760. [PMID: 32385409 PMCID: PMC7210983 DOI: 10.1038/s41598-020-64722-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/20/2020] [Indexed: 12/13/2022] Open
Abstract
On one hand blood-brain barrier (BBB) disturbance aggravates disease progression, on the other it prevents drug access and impedes therapeutic efficacy. Effective ways to modulate barrier function and resolve these issues are sorely needed. Convinced that better understanding of cell-oriented BBB responses could provide valuable insight, and the fact that metabolic dysregulation is prominent in many vascular-related pathological processes associated with BBB disturbance, we hypothesized that differential cell-specific metabolic adaptation majorly influences physiological and pathological barrier functionality. Untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomic profiling was used to obtain individual biochemical fingerprints of primary astrocytes (AC) and brain endothelial cells (EC) during normoxic conditions and increasing hypoxic/ischemic injury and thus a functional readout of cell status. Bioinformatic analyses showed each cell had a distinct metabolic signature. Corroborating their roles in BBB and CNS protection, AC showed an innate ability to dynamically alter their metabolome depending on the insult. Surprisingly, in complete contrast, EC largely maintained their normoxic characteristics in injury situations and their profiles diverged from those of non-brain origin. Tissue specificity/origin is clearly important when considering EC responses. Focusing on energy capacity and utilization we discuss how cell-specific metabolic adaptive capabilities could influence vascular stability and the possibility that altering metabolite levels may be an effective way to modulate brain EC function. Overall this work novel insight into cell-associated metabolic changes, and provides a powerful resource for understanding BBB changes during different injury scenarios.
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15
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A thermodynamic function of glycogen in brain and muscle. Prog Neurobiol 2020; 189:101787. [PMID: 32151532 DOI: 10.1016/j.pneurobio.2020.101787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/30/2020] [Accepted: 03/03/2020] [Indexed: 11/20/2022]
Abstract
Brain and muscle glycogen are generally thought to function as local glucose reserves, for use during transient mismatches between glucose supply and demand. However, quantitative measures show that glucose supply is likely never rate-limiting for energy metabolism in either brain or muscle under physiological conditions. These tissues nevertheless do utilize glycogen during increased energy demand, despite the availability of free glucose, and despite the ATP cost of cycling glucose through glycogen polymer. This seemingly wasteful process can be explained by considering the effect of glycogenolysis on the amount of energy obtained from ATP (ΔG'ATP). The amount of energy obtained from ATP is reduced by elevations in inorganic phosphate (Pi). Glycogen utilization sequesters Pi in the glycogen phosphorylase reaction and in downstream phosphorylated glycolytic intermediates, thereby buffering Pi elevations and maximizing energy yield at sites of rapid ATP consumption. This thermodynamic effect of glycogen may be particularly important in the narrow, spatially constrained astrocyte processes that ensheath neuronal synapses and in cells such as astrocytes and myocytes that release Pi from phosphocreatine during energy demand. The thermodynamic effect may also explain glycolytic super-compensation in brain when glycogen is not available, and aspects of exercise physiology in muscle glycogen phosphorylase deficiency (McArdle disease).
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16
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Matsui T, Soya M, Soya H. Endurance and Brain Glycogen: A Clue Toward Understanding Central Fatigue. ADVANCES IN NEUROBIOLOGY 2019; 23:331-346. [PMID: 31667814 DOI: 10.1007/978-3-030-27480-1_11] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Brain glycogen stored in astrocytes produces lactate as a neuronal energy source transported by monocarboxylate transporters (MCTs) to maintain neuronal functions, such as hippocampus-regulated memory formation. Although exercise activates brain neurons, the role of astrocytic glycogen in the brain during exercise remains unknown. Since muscle glycogen fuels active muscles during exercise, we hypothesized that astrocytic glycogen plays an energetic role in the brain during exercise to maintain endurance capacity through lactate transport. To explore this hypothesis, we have used a rat model of prolonged exercise, microwave irradiation for the accurate detection of brain glycogen, capillary electrophoresis-mass spectrometry-based metabolomics, and inhibitors of glycogenolysis (1,4-dideoxy-1,4-imino-D-arabinitol; DAB) and lactate transport (α-cyano-4-hydroxycinnamate; 4-CIN). During prolonged exhaustive exercise, muscle glycogen was depleted and brain glycogen decreased when associated with decreased blood glucose levels and increased serotonergic activity known as central fatigue factors, suggesting brain glycogen decrease as an integrative factor for central fatigue. Prolonged exhaustive exercise also increased MCT2 protein in the brain, which takes up lactate in neurons, just as muscle MCTs are increased. Metabolomics revealed that brain but not muscle adenosine triphosphate (ATP) was maintained with lactate and other glycogenolytic and glycolytic sources. Intracerebroventricular (icv) injection of DAB suppressed brain lactate production and decreased hippocampal ATP levels at exhaustion. An icv injection of 4-CIN also decreased hippocampal ATP, resulting in lower endurance capacity. Our findings provide direct evidence that astrocytic glycogen-derived lactate fuels the brain to maintain endurance capacity during exhaustive exercise. Brain ATP levels maintained by glycogen might serve as a possible defense mechanism for neurons in the exhausted state.
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Affiliation(s)
- Takashi Matsui
- Sport Neuroscience Division, Faculty of Health and Sport Sciences, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Ibaraki, Japan.
| | - Mariko Soya
- Sport Neuroscience Division, Faculty of Health and Sport Sciences, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Ibaraki, Japan
| | - Hideaki Soya
- Sport Neuroscience Division, Faculty of Health and Sport Sciences, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Ibaraki, Japan.
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17
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Rich LR, Harris W, Brown AM. The Role of Brain Glycogen in Supporting Physiological Function. Front Neurosci 2019; 13:1176. [PMID: 31749677 PMCID: PMC6842925 DOI: 10.3389/fnins.2019.01176] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/17/2019] [Indexed: 01/08/2023] Open
Abstract
Glycogen is present in the mammalian brain but occurs at concentrations so low it is unlikely to act as a conventional energy reserve. Glycogen has the intriguing feature of being located exclusively in astrocytes, but its presence benefits neurones, suggesting that glycogen is metabolized to a conduit that is transported between the glia and neural elements. In the rodent optic nerve model glycogen supports axon conduction in the form of lactate to supplement axonal metabolism during aglycemia, hypoglycemia and during periods of increased energy demand under normoglycemic conditions. In the hippocampus glycogen plays a vital role in supplying the neurones with lactate during memory formation. The physiological processes that glycogen supports, such as learning and memory, imply an inclusive and vital role in supporting physiological brain functions.
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Affiliation(s)
- Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - William Harris
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Department of Neurology, University of Washington, Seattle, WA, United States
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18
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Bordone MP, Salman MM, Titus HE, Amini E, Andersen JV, Chakraborti B, Diuba AV, Dubouskaya TG, Ehrke E, Espindola de Freitas A, Braga de Freitas G, Gonçalves RA, Gupta D, Gupta R, Ha SR, Hemming IA, Jaggar M, Jakobsen E, Kumari P, Lakkappa N, Marsh APL, Mitlöhner J, Ogawa Y, Paidi RK, Ribeiro FC, Salamian A, Saleem S, Sharma S, Silva JM, Singh S, Sulakhiya K, Tefera TW, Vafadari B, Yadav A, Yamazaki R, Seidenbecher CI. The energetic brain - A review from students to students. J Neurochem 2019; 151:139-165. [PMID: 31318452 DOI: 10.1111/jnc.14829] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The past 20 years have resulted in unprecedented progress in understanding brain energy metabolism and its role in health and disease. In this review, which was initiated at the 14th International Society for Neurochemistry Advanced School, we address the basic concepts of brain energy metabolism and approach the question of why the brain has high energy expenditure. Our review illustrates that the vertebrate brain has a high need for energy because of the high number of neurons and the need to maintain a delicate interplay between energy metabolism, neurotransmission, and plasticity. Disturbances to the energetic balance, to mitochondria quality control or to glia-neuron metabolic interaction may lead to brain circuit malfunction or even severe disorders of the CNS. We cover neuronal energy consumption in neural transmission and basic ('housekeeping') cellular processes. Additionally, we describe the most common (glucose) and alternative sources of energy namely glutamate, lactate, ketone bodies, and medium chain fatty acids. We discuss the multifaceted role of non-neuronal cells in the transport of energy substrates from circulation (pericytes and astrocytes) and in the supply (astrocytes and microglia) and usage of different energy fuels. Finally, we address pathological consequences of disrupted energy homeostasis in the CNS.
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Affiliation(s)
- Melina Paula Bordone
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Haley E Titus
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Artem V Diuba
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatsiana G Dubouskaya
- Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Eric Ehrke
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Andiara Espindola de Freitas
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, California, USA
| | | | | | | | - Richa Gupta
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Sharon R Ha
- Baylor College of Medicine, Houston, Texas, USA
| | - Isabel A Hemming
- Brain Growth and Disease Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
| | - Minal Jaggar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Punita Kumari
- Defense Institute of Physiology and allied sciences, Defense Research and Development Organization, Timarpur, Delhi, India
| | - Navya Lakkappa
- Department of Pharmacology, JSS college of Pharmacy, Ooty, India
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany
| | - Yuki Ogawa
- The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | | | | | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Suraiya Saleem
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sorabh Sharma
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Joana M Silva
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal
| | - Shripriya Singh
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Kunjbihari Sulakhiya
- Department of Pharmacy, Indira Gandhi National Tribal University, Amarkantak, India
| | - Tesfaye Wolde Tefera
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Behnam Vafadari
- Institute of environmental medicine, UNIKA-T, Technical University of Munich, Munich, Germany
| | - Anuradha Yadav
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Reiji Yamazaki
- Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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19
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Prah J, Winters A, Chaudhari K, Hersh J, Liu R, Yang SH. Cholesterol sulfate alters astrocyte metabolism and provides protection against oxidative stress. Brain Res 2019; 1723:146378. [PMID: 31425677 DOI: 10.1016/j.brainres.2019.146378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/05/2019] [Accepted: 08/11/2019] [Indexed: 01/21/2023]
Abstract
Cholesterol sulfate (CS) is one of the most important known sterol sulfates in human plasma and it is present as a normal constituent in a variety of human tissues. In both the brain and periphery, CS serves as a substrate for the synthesis of sulfonated adrenal steroids such as pregnenolone sulfate and dehydroepiandrosterone (DHEA) sulfate and as a constituent of many biological membranes including red blood cells where it functions as a stabilizing agent. It also acts as an endogenous regulator of cholesterol synthesis. However, the role of CS in brain metabolism and neurological disorder is unclear. In the current study we investigated the neuroprotective action of CS as well as its role in brain energy metabolism. The neuroprotective effect of CS and its role on cell metabolism were determined in primary astrocyte prepared from the cortex of postnatal day 0-2 C57BL/6 pups and a hippocampal HT-22 cell line using Calcein AM and MTT cell viability assay, flow cytometry, Seahorse extracellular flux analysis, and metabolism assay kits. We found that CS attenuates glutamate and rotenone induced cell death in HT-22 cells, decrease glutamate induced mitochondria membrane potential collapse, and reactive oxygen species production. Additionally, CS activates the Akt/Bcl2 pathway. We observed that CS impacts astrocyte metabolism by increasing mitochondrial phosphorylation, ATP, and glycogen contents. Our study demonstrated that CS modulates brain energy metabolism and its neuroprotective effects might be due to the activation of Akt signaling or its ability to decrease reactive oxygen species production.
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Affiliation(s)
- Jude Prah
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ali Winters
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Kiran Chaudhari
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Jessica Hersh
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ran Liu
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Shao-Hua Yang
- Department of Pharmacology and Neuroscience, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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20
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Stanley S, Moheet A, Seaquist ER. Central Mechanisms of Glucose Sensing and Counterregulation in Defense of Hypoglycemia. Endocr Rev 2019; 40:768-788. [PMID: 30689785 PMCID: PMC6505456 DOI: 10.1210/er.2018-00226] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
Glucose homeostasis requires an organism to rapidly respond to changes in plasma glucose concentrations. Iatrogenic hypoglycemia as a result of treatment with insulin or sulfonylureas is the most common cause of hypoglycemia in humans and is generally only seen in patients with diabetes who take these medications. The first response to a fall in glucose is the detection of impending hypoglycemia by hypoglycemia-detecting sensors, including glucose-sensing neurons in the hypothalamus and other regions. This detection is then linked to a series of neural and hormonal responses that serve to prevent the fall in blood glucose and restore euglycemia. In this review, we discuss the current state of knowledge about central glucose sensing and how detection of a fall in glucose leads to the stimulation of counterregulatory hormone and behavior responses. We also review how diabetes and recurrent hypoglycemia impact glucose sensing and counterregulation, leading to development of impaired awareness of hypoglycemia in diabetes.
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Affiliation(s)
- Sarah Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Amir Moheet
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Elizabeth R Seaquist
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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21
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Fasting blood glucose levels in patients with different types of diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 162:277-292. [PMID: 30905457 DOI: 10.1016/bs.pmbts.2019.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Normal human physiology is dependent on a tight control of the fasting blood glucose (FBG) levels. The islets of pancreas maintains FBG levels within a narrow range of 4-6mmol/L by secreting various hormones, especially insulin and glucagon. However, the hormone secretions by the islets of pancreas are governed by a collective effort among pancreas-islet axis, brain-islet axis, liver-islet axis, gut-islet axis, and adipocyte/myocyte-islet axis. Furthermore, the damage of pancreas, vascular system, brain, liver, intestine, adipose, muscle, and other organs and tissues might affect FBG levels through insulin resistance or impaired insulin signaling, which is the hallmark of type 2 diabetes. In this study, 320,572 clinical lab test results of FBG levels from healthy individuals and patients with 64 different types of diseases during the past 5 years in our hospital were retrieved and analyzed. Based on the mean (SD), median, and p (-Log10p) values, we found 57/64 diseases including type 2 diabetes, pancreatitis, diabetic nephropathy, and pancreatic cancer had significantly (p<0.05, -Log10p>1.30) increased whereas 6/64 diseases including preeclampsia, Wilms' tumor, and lupus erythematous had significantly decreased FBG levels compared to that of healthy controls. These data indicated that the increased FBG levels might be a general pathophysiological property of diseased tissues or organs and the increased FBG levels might be a consequence but not the cause for either prediabetes or type 2 diabetes.
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22
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Fernandez CG, Hamby ME, McReynolds ML, Ray WJ. The Role of APOE4 in Disrupting the Homeostatic Functions of Astrocytes and Microglia in Aging and Alzheimer's Disease. Front Aging Neurosci 2019; 11:14. [PMID: 30804776 PMCID: PMC6378415 DOI: 10.3389/fnagi.2019.00014] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/16/2019] [Indexed: 12/20/2022] Open
Abstract
APOE4 is the greatest genetic risk factor for late-onset Alzheimer’s disease (AD), increasing the risk of developing the disease by 3-fold in the 14% of the population that are carriers. Despite 25 years of research, the exact mechanisms underlying how APOE4 contributes to AD pathogenesis remain incompletely defined. APOE in the brain is primarily expressed by astrocytes and microglia, cell types that are now widely appreciated to play key roles in the pathogenesis of AD; thus, a picture is emerging wherein APOE4 disrupts normal glial cell biology, intersecting with changes that occur during normal aging to ultimately cause neurodegeneration and cognitive dysfunction. This review article will summarize how APOE4 alters specific pathways in astrocytes and microglia in the context of AD and the aging brain. APOE itself, as a secreted lipoprotein without enzymatic activity, may prove challenging to directly target therapeutically in the classical sense. Therefore, a deeper understanding of the underlying pathways responsible for APOE4 toxicity is needed so that more tractable pathways and drug targets can be identified to reduce APOE4-mediated disease risk.
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Affiliation(s)
- Celia G Fernandez
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Mary E Hamby
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Morgan L McReynolds
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - William J Ray
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
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23
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Brown AM, Rich LR, Ransom BR. Metabolism of Glycogen in Brain White Matter. ADVANCES IN NEUROBIOLOGY 2019; 23:187-207. [PMID: 31667810 DOI: 10.1007/978-3-030-27480-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Brain glycogen is a specialized energy buffer, rather than a conventional reserve. In the rodent optic nerve, a central white matter tract, it is located in astrocytes, where it is converted to lactate, which is then shuttled intercellularly from the astrocyte to the axon. This basic pathway was elucidated from non-physiological experiments in which the nerve was deprived of exogenous glucose. However, this shuttling also occurs under physiological conditions, when tissue energy demand is increased above baseline levels in the presence of normoglycemic concentrations of glucose. The signaling mechanism by which axons alert astrocytes to their increased energy requirement is likely to be elevated interstitial K+, the inevitable consequence of increased neuronal activity.
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Affiliation(s)
- Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, UK. .,Department of Neurology, University on Washington, Seattle, WA, USA.
| | - Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Bruce R Ransom
- School of Life Sciences, University of Nottingham, Nottingham, UK.,Department of Neurology, University on Washington, Seattle, WA, USA
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Bastian C, Quinn J, Doherty C, Franke C, Faris A, Brunet S, Baltan S. Role of Brain Glycogen During Ischemia, Aging and Cell-to-Cell Interactions. ADVANCES IN NEUROBIOLOGY 2019; 23:347-361. [PMID: 31667815 DOI: 10.1007/978-3-030-27480-1_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The astrocyte-neuron lactate transfer shuttle (ANLS) is one of the important metabolic systems that provides a physiological infrastructure for glia-neuronal interactions where specialized architectural organization supports the function. Perivascular astrocyte end-feet take up glucose via glucose transporter 1 to actively regulate glycogen stores, such that high ambient glucose upregulates glycogen and low levels of glucose deplete glycogen stores. A rapid breakdown of glycogen into lactate during increased neuronal activity or low glucose conditions becomes essential for maintaining axon function. However, it fails to benefit axon function during an ischemic episode in white matter (WM). Aging causes a remarkable change in astrocyte architecture characterized by thicker, larger processes oriented parallel to axons, as opposed to vertically-transposing processes. Subsequently, aging axons become more vulnerable to depleted glycogen, although aging axons can use lactate as efficiently as young axons. Lactate equally supports function during aglycemia in corpus callosum (CC), which consists of a mixture of myelinated and unmyelinated axons. Moreover, axon function in CC shows greater resilience to a lack of glucose compared to optic nerve, although both WM tracts show identical recovery after aglycemic injury. Interestingly, emerging evidence implies that a lactate transport system is not exclusive to astrocytes, as oligodendrocytes support the axons they myelinate, suggesting another metabolic coupling pathway in WM. Future studies are expected to unravel the details of oligodendrocyte-axon lactate metabolic coupling to establish that all WM components metabolically cooperate and that lactate may be the universal metabolite to sustain central nervous system function.
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Affiliation(s)
- Chinthasagar Bastian
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - John Quinn
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Christine Doherty
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Caroline Franke
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Anna Faris
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sylvain Brunet
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Selva Baltan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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Coggan JS, Keller D, Calì C, Lehväslaiho H, Markram H, Schürmann F, Magistretti PJ. Norepinephrine stimulates glycogenolysis in astrocytes to fuel neurons with lactate. PLoS Comput Biol 2018; 14:e1006392. [PMID: 30161133 PMCID: PMC6160207 DOI: 10.1371/journal.pcbi.1006392] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/27/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022] Open
Abstract
The mechanism of rapid energy supply to the brain, especially to accommodate the heightened metabolic activity of excited states, is not well-understood. We explored the role of glycogen as a fuel source for neuromodulation using the noradrenergic stimulation of glia in a computational model of the neural-glial-vasculature ensemble (NGV). The detection of norepinephrine (NE) by the astrocyte and the coupled cAMP signal are rapid and largely insensitive to the distance of the locus coeruleus projection release sites from the glia, implying a diminished impact for volume transmission in high affinity receptor transduction systems. Glucosyl-conjugated units liberated from glial glycogen by NE-elicited cAMP second messenger transduction winds sequentially through the glycolytic cascade, generating robust increases in NADH and ATP before pyruvate is finally transformed into lactate. This astrocytic lactate is rapidly exported by monocarboxylate transporters to the associated neuron, demonstrating that the astrocyte-to-neuron lactate shuttle activated by glycogenolysis is a likely fuel source for neuromodulation and enhanced neural activity. Altogether, the energy supply for both astrocytes and neurons can be supplied rapidly by glycogenolysis upon neuromodulatory stimulus. Although efficient compared to computers, the human brain utilizes energy at 10-fold the rate of other organs by mass. How the brain is supplied with sufficient on-demand energy to support its activity in the absence of neuronal storage capacity remains unknown. Neurons are not capable of meeting their own energy requirements, instead energy supply in the brain is managed by an oligocellular cartel composed of neurons, glia and the local vasculature (NGV), wherein glia can provide the ergogenic metabolite lactate to the neuron in a process called the astrocyte-to-neuron shuttle (ANLS). The only means of energy storage in the brain is glycogen, a polymerized form of glucose that is localized largely to astrocytes, but its exact role and conditions of use are not clear. In this computational model we show that neuromodulatory stimulation by norepinephrine induces astrocytes to recover glucosyl subunits from glycogen for use in a glycolytic process that favors the production of lactate. The ATP and NADH produced support metabolism in the astrocyte while the lactate is exported to feed the neuron. Thus, rapid energy demands by both neurons and glia in a stimulated brain can be met by glycogen mobilization.
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Affiliation(s)
- Jay S. Coggan
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- * E-mail: (JSC); (PJM)
| | - Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Corrado Calì
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Heikki Lehväslaiho
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Felix Schürmann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Pierre J. Magistretti
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
- * E-mail: (JSC); (PJM)
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Choi SH, Kim HJ, Cho HJ, Park SD, Lee NE, Hwang SH, Cho IH, Hwang H, Rhim H, Kim HC, Nah SY. Gintonin, a Ginseng-Derived Exogenous Lysophosphatidic Acid Receptor Ligand, Protects Astrocytes from Hypoxic and Re-oxygenation Stresses Through Stimulation of Astrocytic Glycogenolysis. Mol Neurobiol 2018; 56:3280-3294. [PMID: 30117105 DOI: 10.1007/s12035-018-1308-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 08/08/2018] [Indexed: 11/25/2022]
Abstract
Astrocytes are a unique brain cell-storing glycogen and express lysophosphatidic acid (LPA) receptors. Gintonin is a ginseng-derived exogenous G protein-coupled LPA receptor ligand. Accumulating evidence shows that astrocytes serve as an energy supplier to neurons through astrocytic glycogenolysis under physiological and pathophysiological conditions. However, little is known about the relationships between LPA receptors and astrocytic glycogenolysis or about the roles of LPA receptors in hypoxia and re-oxygenation stresses. In the present study, we examined the functions of gintonin-mediated astrocytic glycogenolysis in adenosine triphosphate (ATP) production, glutamate uptake, and cell viability under normoxic, hypoxic, and re-oxygenation conditions. The application of gintonin or LPA to astrocytes induced glycogenolysis in concentration- and time-dependent manners. The stimulation of gintonin-mediated astrocytic glycogenolysis was achieved through the LPA receptor-Gαq/11 protein-phospholipase C-inositol 1,4,5-trisphosphate receptor-intracellular calcium ([Ca2+]i) transient pathway. Gintonin treatment to astrocytes increased the phosphorylation of brain phosphorylase kinase, with sensitive manner to K252a, an inhibitor of phosphorylase kinase. Gintonin-mediated astrocytic glycogenolysis was blocked by isofagomine, a glycogen phosphorylase inhibitor. Gintonin additionally increased astrocytic glycogenolysis under hypoxic and re-oxygenation conditions. Moreover, gintonin increased ATP production, glutamate uptake, and cell viability under the hypoxic and re-oxygenation conditions. Collectively, we found that the gintonin-mediated [Ca2+]i transients regulated by LPA receptors were coupled to astrocytic glycogenolysis and that stimulation of gintonin-mediated astrocytic glycogenolysis was coupled to ATP production and glutamate uptake under hypoxic and re-oxygenation conditions, ultimately protecting astrocytes. Hence, the gintonin-mediated astrocytic energy that is modulated via LPA receptors helps to protect astrocytes under hypoxia and re-oxygenation stresses.
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Affiliation(s)
- Sun-Hye Choi
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Hyeon-Joong Kim
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Hee-Jung Cho
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Sang-Deuk Park
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Na-Eun Lee
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea
| | - Sung-Hee Hwang
- Department of Pharmaceutical Engineering, College of Health Sciences, Sangji University, Wonju, 26339, South Korea
| | - Ik-Hyun Cho
- Department of Convergence Medical Science, College of Korean Medicine, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Hongik Hwang
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Hyewhon Rhim
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology program, College of Pharmacy, Kangwon National University, Chunchon, 24341, South Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, 05029, South Korea.
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27
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López-Gambero AJ, Martínez F, Salazar K, Cifuentes M, Nualart F. Brain Glucose-Sensing Mechanism and Energy Homeostasis. Mol Neurobiol 2018; 56:769-796. [PMID: 29796992 DOI: 10.1007/s12035-018-1099-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/25/2018] [Indexed: 01/02/2023]
Abstract
The metabolic and energy state of the organism depends largely on the availability of substrates, such as glucose for ATP production, necessary for maintaining physiological functions. Deregulation in glucose levels leads to the appearance of pathological signs that result in failures in the cardiovascular system and various diseases, such as diabetes, obesity, nephropathy, and neuropathy. Particularly, the brain relies on glucose as fuel for the normal development of neuronal activity. Regions adjacent to the cerebral ventricles, such as the hypothalamus and brainstem, exercise central control in energy homeostasis. These centers house nuclei of neurons whose excitatory activity is sensitive to changes in glucose levels. Determining the different detection mechanisms, the phenotype of neurosecretion, and neural connections involving glucose-sensitive neurons is essential to understanding the response to hypoglycemia through modulation of food intake, thermogenesis, and activation of sympathetic and parasympathetic branches, inducing glucagon and epinephrine secretion and other hypothalamic-pituitary axis-dependent counterregulatory hormones, such as glucocorticoids and growth hormone. The aim of this review focuses on integrating the current understanding of various glucose-sensing mechanisms described in the brain, thereby establishing a relationship between neuroanatomy and control of physiological processes involved in both metabolic and energy balance. This will advance the understanding of increasingly prevalent diseases in the modern world, especially diabetes, and emphasize patterns that regulate and stimulate intake, thermogenesis, and the overall synergistic effect of the neuroendocrine system.
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Affiliation(s)
- A J López-Gambero
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile.,Department of Cell Biology, Genetics and Physiology, University of Malaga, IBIMA, BIONAND, Andalusian Center for Nanomedicine and Biotechnology and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, Málaga, Spain
| | - F Martínez
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
| | - K Salazar
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
| | - M Cifuentes
- Department of Cell Biology, Genetics and Physiology, University of Malaga, IBIMA, BIONAND, Andalusian Center for Nanomedicine and Biotechnology and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, Málaga, Spain.
| | - F Nualart
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile. .,Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
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28
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Bylicky MA, Mueller GP, Day RM. Mechanisms of Endogenous Neuroprotective Effects of Astrocytes in Brain Injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:6501031. [PMID: 29805731 PMCID: PMC5901819 DOI: 10.1155/2018/6501031] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/19/2018] [Indexed: 12/11/2022]
Abstract
Astrocytes, once believed to serve only as "glue" for the structural support of neurons, have been demonstrated to serve critical functions for the maintenance and protection of neurons, especially under conditions of acute or chronic injury. There are at least seven distinct mechanisms by which astrocytes protect neurons from damage; these are (1) protection against glutamate toxicity, (2) protection against redox stress, (3) mediation of mitochondrial repair mechanisms, (4) protection against glucose-induced metabolic stress, (5) protection against iron toxicity, (6) modulation of the immune response in the brain, and (7) maintenance of tissue homeostasis in the presence of DNA damage. Astrocytes support these critical functions through specialized responses to stress or toxic conditions. The detoxifying activities of astrocytes are essential for maintenance of the microenvironment surrounding neurons and in whole tissue homeostasis. Improved understanding of the mechanisms by which astrocytes protect the brain could lead to the development of novel targets for the development of neuroprotective strategies.
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Affiliation(s)
- Michelle A. Bylicky
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Gregory P. Mueller
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Regina M. Day
- Department of Pharmacology and Molecular Therapeutics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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29
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Bak LK, Walls AB, Schousboe A, Waagepetersen HS. Astrocytic glycogen metabolism in the healthy and diseased brain. J Biol Chem 2018; 293:7108-7116. [PMID: 29572349 DOI: 10.1074/jbc.r117.803239] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The brain contains a fairly low amount of glycogen, mostly located in astrocytes, a fact that has prompted the suggestion that glycogen does not have a significant physiological role in the brain. However, glycogen metabolism in astrocytes is essential for several key physiological processes and is adversely affected in disease. For instance, diminished ability to break down glycogen impinges on learning, and epilepsy, Alzheimer's disease, and type 2 diabetes are all associated with abnormal astrocyte glycogen metabolism. Glycogen metabolism supports astrocytic K+ and neurotransmitter glutamate uptake and subsequent glutamine synthesis-three fundamental steps in excitatory signaling at most brain synapses. Thus, there is abundant evidence for a key role of glycogen in brain function. Here, we summarize the physiological brain functions that depend on glycogen, discuss glycogen metabolism in disease, and investigate how glycogen breakdown is regulated at the cellular and molecular levels.
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Affiliation(s)
- Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Anne B Walls
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
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30
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Ogunleke A, Recur B, Balacey H, Chen HH, Delugin M, Hwu Y, Javerzat S, Petibois C. 3D chemical imaging of the brain using quantitative IR spectro-microscopy. Chem Sci 2018; 9:189-198. [PMID: 29629087 PMCID: PMC5869290 DOI: 10.1039/c7sc03306k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 10/13/2017] [Indexed: 01/14/2023] Open
Abstract
Three-dimensional (3D) histology is the next frontier for modern anatomo-pathology. Characterizing abnormal parameters in a tissue is essential to understand the rationale of pathology development. However, there is no analytical technique, in vivo or histological, that is able to discover such abnormal features and provide a 3D distribution at microscopic resolution. Here, we introduce a unique high-throughput infrared (IR) microscopy method that combines automated image correction and subsequent spectral data analysis for 3D-IR image reconstruction. We performed spectral analysis of a complete organ for a small animal model, a mouse brain with an implanted glioma tumor. The 3D-IR image is reconstructed from 370 consecutive tissue sections and corrected using the X-ray tomogram of the organ for an accurate quantitative analysis of the chemical content. A 3D matrix of 89 × 106 IR spectra is generated, allowing us to separate the tumor mass from healthy brain tissues based on various anatomical, chemical, and metabolic parameters. We demonstrate that quantitative metabolic parameters can be extracted from the IR spectra for the characterization of the brain vs. tumor metabolism (assessing the Warburg effect in tumors). Our method can be further exploited by searching for the whole spectral profile, discriminating tumor vs. healthy tissue in a non-supervised manner, which we call 'spectromics'.
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Affiliation(s)
- Abiodun Ogunleke
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
| | - Benoit Recur
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
| | - Hugo Balacey
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
| | - Hsiang-Hsin Chen
- Academia Sinica , Institute of Physics , 128 Sec. 2, Academia Rd., Nankang , Taipei 11529 , Taiwan , Republic of China
| | - Maylis Delugin
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
| | - Yeukuang Hwu
- Academia Sinica , Institute of Physics , 128 Sec. 2, Academia Rd., Nankang , Taipei 11529 , Taiwan , Republic of China
| | - Sophie Javerzat
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
| | - Cyril Petibois
- University of Bordeaux , Inserm U1029 LAMC , Allée Geoffroy Saint-Hilaire Bat. B2, F33600 Pessac , France . ;
- Academia Sinica , Institute of Physics , 128 Sec. 2, Academia Rd., Nankang , Taipei 11529 , Taiwan , Republic of China
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31
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Lanthanum chloride reduces lactate production in primary culture rat cortical astrocytes and suppresses primary co-culture rat cortical astrocyte-neuron lactate transport. Arch Toxicol 2017; 92:1407-1419. [DOI: 10.1007/s00204-017-2148-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/14/2017] [Indexed: 12/18/2022]
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32
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Astrocytic glycogen-derived lactate fuels the brain during exhaustive exercise to maintain endurance capacity. Proc Natl Acad Sci U S A 2017; 114:6358-6363. [PMID: 28515312 DOI: 10.1073/pnas.1702739114] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Brain glycogen stored in astrocytes provides lactate as an energy source to neurons through monocarboxylate transporters (MCTs) to maintain neuronal functions such as hippocampus-regulated memory formation. Although prolonged exhaustive exercise decreases brain glycogen, the role of this decrease and lactate transport in the exercising brain remains less clear. Because muscle glycogen fuels exercising muscles, we hypothesized that astrocytic glycogen plays an energetic role in the prolonged-exercising brain to maintain endurance capacity through lactate transport. To test this hypothesis, we used a rat model of exhaustive exercise and capillary electrophoresis-mass spectrometry-based metabolomics to observe comprehensive energetics of the brain (cortex and hippocampus) and muscle (plantaris). At exhaustion, muscle glycogen was depleted but brain glycogen was only decreased. The levels of MCT2, which takes up lactate in neurons, increased in the brain, as did muscle MCTs. Metabolomics revealed that brain, but not muscle, ATP was maintained with lactate and other glycogenolytic/glycolytic sources. Intracerebroventricular injection of the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-d-arabinitol did not affect peripheral glycemic conditions but suppressed brain lactate production and decreased hippocampal ATP levels at exhaustion. An MCT2 inhibitor, α-cyano-4-hydroxy-cinnamate, triggered a similar response that resulted in lower endurance capacity. These findings provide direct evidence for the energetic role of astrocytic glycogen-derived lactate in the exhaustive-exercising brain, implicating the significance of brain glycogen level in endurance capacity. Glycogen-maintained ATP in the brain is a possible defense mechanism for neurons in the exhausted brain.
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33
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Waitt AE, Reed L, Ransom BR, Brown AM. Emerging Roles for Glycogen in the CNS. Front Mol Neurosci 2017; 10:73. [PMID: 28360839 PMCID: PMC5352909 DOI: 10.3389/fnmol.2017.00073] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/03/2017] [Indexed: 11/20/2022] Open
Abstract
The ability of glycogen, the depot into which excess glucose is stored in mammals, to act as a source of rapidly available energy substrate, has been exploited by several organs for both general and local advantage. The liver, expressing the highest concentration of glycogen maintains systemic normoglycemia ensuring the brain receives a supply of glucose in excess of demand. However the brain also contains glycogen, although its role is more specialized. Brain glycogen is located exclusively in astrocytes in the adult, with the exception of pathological conditions, thus in order to benefit neurons, and energy conduit (lactate) is trafficked inter-cellularly. Such a complex scheme requires cell type specific expression of a variety of metabolic enzymes and transporters. Glycogen supports neural elements during withdrawal of glucose, but once the limited buffer of glycogen is exhausted neural function fails and irreversible injury ensues. Under physiological conditions glycogen acts to provide supplemental substrates when ambient glucose is unable to support function during increased energy demand. Glycogen also supports learning and memory where it provides lactate to neurons during the conditioning phase of in vitro long-term potentiation (LTP), an experimental correlate of learning. Inhibiting the breakdown of glycogen or intercellular transport of lactate in in vivo rat models inhibits the retention of memory. Our current understanding of the importance of brain glycogen is expanding to encompass roles that are fundamental to higher brain function.
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Affiliation(s)
- Alice E. Waitt
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Liam Reed
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Bruce R. Ransom
- Department of Neurology, University of WashingtonSeattle, WA, USA
| | - Angus M. Brown
- School of Life Sciences, University of NottinghamNottingham, UK
- Department of Neurology, University of WashingtonSeattle, WA, USA
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Saggu R. Interleukin-1beta-induced reduction of tissue water diffusion in the juvenile rat brain on ADC MRI is not associated with 31P MRS-detectable energy failure. J Inflamm (Lond) 2016; 13:9. [PMID: 26989349 PMCID: PMC4794816 DOI: 10.1186/s12950-016-0118-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/10/2016] [Indexed: 11/21/2022] Open
Abstract
Background It has long been known that an intrastriatal microinjection of the archetypal pro-inflammatory cytokine, interleukin-1beta (IL-1β), in juvenile rats induces a chronic reduction in the apparent diffusion coefficient (ADC) of tissue water on magnetic resonance imaging (MRI). Reduced ADC during acute cerebral ischaemia is an established indicator of metabolic failure whereas the cause of the IL-1β-induced reduction remains to be deciphered. Previously, it has been shown that IL-1β does not perturb the phosphorus (31P) magnetic resonance spectroscopy (MRS)-detectable energy status of an ex vivo preparation of rat brain parenchyma that is devoid of a functional vasculature component. However, brain energy status following an IL-1β challenge in vivo remains to be examined. Methods This study is the first longitudinal in vivo examination of the correlation of ADC MRI with localised 31P MRS signals obtained specifically from within the injected and non-injected striatum following IL-1β (1 ng/ul or 100 ng/ul) challenge, in real-time. Results Despite observing a chronic reduction in ADC at either dose of IL-1β challenge, energy compromise was not detected at any time point. Conclusions The IL-1β-induced effects pertaining to a functional vasculature such as leukocyte recruitment, blood–brain barrier (BBB) breakdown and blood flow changes are unlikely to impact on overall tissue energy status. Compared to classic ischaemia, there is dissociation between ADC and energy status within an IL-1β-induced lesion in vivo.
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35
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Chhabria K, Chakravarthy VS. Low-Dimensional Models of "Neuro-Glio-Vascular Unit" for Describing Neural Dynamics under Normal and Energy-Starved Conditions. Front Neurol 2016; 7:24. [PMID: 27014179 PMCID: PMC4783418 DOI: 10.3389/fneur.2016.00024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 02/18/2016] [Indexed: 01/08/2023] Open
Abstract
The motivation of developing simple minimal models for neuro-glio-vascular (NGV) system arises from a recent modeling study elucidating the bidirectional information flow within the NGV system having 89 dynamic equations (1). While this was one of the first attempts at formulating a comprehensive model for neuro-glio-vascular system, it poses severe restrictions in scaling up to network levels. On the contrary, low-dimensional models are convenient devices in simulating large networks that also provide an intuitive understanding of the complex interactions occurring within the NGV system. The key idea underlying the proposed models is to describe the glio-vascular system as a lumped system, which takes neural firing rate as input and returns an “energy” variable (analogous to ATP) as output. To this end, we present two models: biophysical neuro-energy (Model 1 with five variables), comprising KATP channel activity governed by neuronal ATP dynamics, and the dynamic threshold (Model 2 with three variables), depicting the dependence of neural firing threshold on the ATP dynamics. Both the models show different firing regimes, such as continuous spiking, phasic, and tonic bursting depending on the ATP production coefficient, ɛp, and external current. We then demonstrate that in a network comprising such energy-dependent neuron units, ɛp could modulate the local field potential (LFP) frequency and amplitude. Interestingly, low-frequency LFP dominates under low ɛp conditions, which is thought to be reminiscent of seizure-like activity observed in epilepsy. The proposed “neuron-energy” unit may be implemented in building models of NGV networks to simulate data obtained from multimodal neuroimaging systems, such as functional near infrared spectroscopy coupled to electroencephalogram and functional magnetic resonance imaging coupled to electroencephalogram. Such models could also provide a theoretical basis for devising optimal neurorehabilitation strategies, such as non-invasive brain stimulation for stroke patients.
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Affiliation(s)
- Karishma Chhabria
- Computational Biophysics and Neurosciences Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras , Chennai , India
| | - V Srinivasa Chakravarthy
- Computational Biophysics and Neurosciences Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras , Chennai , India
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Villarroel-Espíndola F, Tapia C, González-Stegmaier R, Concha II, Slebe JC. Polyglucosan Molecules Induce Mitochondrial Impairment and Apoptosis in Germ Cells Without Affecting the Integrity and Functionality of Sertoli Cells. J Cell Physiol 2016; 231:2142-52. [DOI: 10.1002/jcp.25315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/19/2016] [Indexed: 11/09/2022]
Affiliation(s)
| | - Cynthia Tapia
- Instituto de Bioquímica y Microbiología; Universidad Austral de Chile; Valdivia Chile
| | | | - Ilona I. Concha
- Instituto de Bioquímica y Microbiología; Universidad Austral de Chile; Valdivia Chile
| | - Juan Carlos Slebe
- Instituto de Bioquímica y Microbiología; Universidad Austral de Chile; Valdivia Chile
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Hong S, Ahn JY, Cho GS, Kim IH, Cho JH, Ahn JH, Park JH, Won MH, Chen BH, Shin BN, Tae HJ, Park SM, Cho JH, Choi SY, Lee JC. Monocarboxylate transporter 4 plays a significant role in the neuroprotective mechanism of ischemic preconditioning in transient cerebral ischemia. Neural Regen Res 2015; 10:1604-11. [PMID: 26692857 PMCID: PMC4660753 DOI: 10.4103/1673-5374.167757] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Monocarboxylate transporters (MCTs), which carry monocarboxylates such as lactate across biological membranes, have been associated with cerebral ischemia/reperfusion process. In this study, we studied the effect of ischemic preconditioning (IPC) on MCT4 immunoreactivity after 5 minutes of transient cerebral ischemia in the gerbil. Animals were randomly designated to four groups (sham-operated group, ischemia only group, IPC + sham-operated group and IPC + ischemia group). A serious loss of neuron was found in the stratum pyramidale of the hippocampal CA1 region (CA1), not CA2/3, of the ischemia-only group at 5 days post-ischemia; however, in the IPC + ischemia groups, neurons in the stratum pyramidale of the CA1 were well protected. Weak MCT4 immunoreactivity was found in the stratum pyramidale of the CA1 in the sham-operated group. MCT4 immunoreactivity in the stratum pyramidale began to decrease at 2 days post-ischemia and was hardly detected at 5 days post-ischemia; at this time point, MCT4 immunoreactivity was newly expressed in astrocytes. In the IPC + sham-operated group, MCT4 immunoreactivity in the stratum pyramidale of the CA1 was increased compared with the sham-operated group, and, in the IPC + ischemia group, MCT4 immunoreactivity was also increased in the stratum pyramidale compared with the ischemia only group. Briefly, present findings show that IPC apparently protected CA1 pyramidal neurons and increased or maintained MCT4 expression in the stratum pyramidale of the CA1 after transient cerebral ischemia. Our findings suggest that MCT4 appears to play a significant role in the neuroprotective mechanism of IPC in the gerbil with transient cerebral ischemia.
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Affiliation(s)
- Seongkweon Hong
- Department of Surgery, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Ji Yun Ahn
- Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, South Korea ; Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Geum-Sil Cho
- Department of Neuroscience, College of Medicine, Korea University, Seoul, South Korea
| | - In Hye Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Jeong Hwi Cho
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Ji Hyeon Ahn
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Joon Ha Park
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Bai Hui Chen
- Department of Physiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Bich-Na Shin
- Department of Physiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Hyun-Jin Tae
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, South Korea
| | - Seung Min Park
- Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, South Korea ; Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Soo Young Choi
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, South Korea
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
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Magistretti PJ, Allaman I. A cellular perspective on brain energy metabolism and functional imaging. Neuron 2015; 86:883-901. [PMID: 25996133 DOI: 10.1016/j.neuron.2015.03.035] [Citation(s) in RCA: 725] [Impact Index Per Article: 80.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The energy demands of the brain are high: they account for at least 20% of the body's energy consumption. Evolutionary studies indicate that the emergence of higher cognitive functions in humans is associated with an increased glucose utilization and expression of energy metabolism genes. Functional brain imaging techniques such as fMRI and PET, which are widely used in human neuroscience studies, detect signals that monitor energy delivery and use in register with neuronal activity. Recent technological advances in metabolic studies with cellular resolution have afforded decisive insights into the understanding of the cellular and molecular bases of the coupling between neuronal activity and energy metabolism and point at a key role of neuron-astrocyte metabolic interactions. This article reviews some of the most salient features emerging from recent studies and aims at providing an integration of brain energy metabolism across resolution scales.
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Affiliation(s)
- Pierre J Magistretti
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia; Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland; Center for Psychiatric Neurosciences, Department of Psychiatry, University of Lausanne, Lausanne 1008, Switzerland.
| | - Igor Allaman
- Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
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Abstract
Glycogen provides an important glucose reservoir in the brain since the concentration of glucosyl units stored in glycogen is several fold higher than free glucose available in brain tissue. We have previously reported 3-4 µmol/g brain glycogen content using in vivo (13)C magnetic resonance spectroscopy (MRS) in conjunction with [1-(13)C]glucose administration in healthy humans, while higher levels were reported in the rodent brain. Due to the slow turnover of bulk brain glycogen in humans, complete turnover of the glycogen pool, estimated to take 3-5 days, was not observed in these prior studies. In an attempt to reach complete turnover and thereby steady state (13)C labeling in glycogen, here we administered [1-(13)C]glucose to healthy volunteers for 80 h. To eliminate any net glycogen synthesis during this period and thereby achieve an accurate estimate of glycogen concentration, volunteers were maintained at euglycemic blood glucose levels during [1-(13)C]glucose administration and (13)C-glycogen levels in the occipital lobe were measured by (13)C MRS approximately every 12 h. Finally, we fitted the data with a biophysical model that was recently developed to take into account the tiered structure of the glycogen molecule and additionally incorporated blood glucose levels and isotopic enrichments as input function in the model. We obtained excellent fits of the model to the (13)C-glycogen data, and glycogen content in the healthy human brain tissue was found to be 7.8 ± 0.3 µmol/g, a value substantially higher than previous estimates of glycogen content in the human brain.
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Affiliation(s)
- Gülin Öz
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, 2021 6th St. S.E., Minneapolis, MN, 55455, USA.
| | - Mauro DiNuzzo
- Museo storico della fisica e Centro di studi e ricerche Enrico Fermi, Rome, Italy
| | - Anjali Kumar
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Amir Moheet
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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Identification of proteins in hyperglycemia and stroke animal models. J Surg Res 2015; 200:365-73. [PMID: 26265382 DOI: 10.1016/j.jss.2015.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 01/23/2023]
Abstract
BACKGROUND Stroke is a major cause of disability and death in adults. Diabetes mellitus is a metabolic disorder that strongly increases the risk of severe vascular diseases. This study compared changes in proteins of the cerebral cortex during ischemic brain injury between nondiabetic and diabetic animals. METHODS Adult male rats were injected with streptozotocin (40 mg/kg) via the intraperitoneal route to induce diabetes and underwent surgical middle cerebral artery occlusion (MCAO) 4 wk after streptozotocin treatment. Cerebral cortex tissues were collected 24 h after MCAO and cerebral cortex proteins were analyzed by two-dimensional gel electrophoresis and mass spectrometry. RESULTS Several proteins were identified as differentially expressed between nondiabetic and diabetic animals. Among the identified proteins, we focused on the following metabolism-related enzymes: isocitrate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, adenosylhomocysteinase, pyruvate kinase, and glucose-6-phosphate isomerase (neuroleukin). Expression of these proteins was decreased in animals that underwent MCAO. Moreover, protein expression was reduced to a greater extent in diabetic animals than in nondiabetic animals. Reverse transcription-polymerase chain reaction analysis confirmed that the diabetic condition exacerbates the decrease in expression of metabolism-related proteins after MCAO. CONCLUSIONS These results suggest that the diabetic condition may exacerbate brain damage during focal cerebral ischemia through the downregulation of metabolism-related proteins.
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Karus C, Ziemens D, Rose CR. Lactate rescues neuronal sodium homeostasis during impaired energy metabolism. Channels (Austin) 2015; 9:200-8. [PMID: 26039160 PMCID: PMC4594511 DOI: 10.1080/19336950.2015.1050163] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Recently, we established that recurrent activity evokes network sodium oscillations in neurons and astrocytes in hippocampal tissue slices. Interestingly, metabolic integrity of astrocytes was essential for the neurons' capacity to maintain low sodium and to recover from sodium loads, indicating an intimate metabolic coupling between the 2 cell types. Here, we studied if lactate can support neuronal sodium homeostasis during impaired energy metabolism by analyzing whether glucose removal, pharmacological inhibition of glycolysis and/or addition of lactate affect cellular sodium regulation. Furthermore, we studied the effect of lactate on sodium regulation during recurrent network activity and upon inhibition of the glial Krebs cycle by sodium-fluoroacetate. Our results indicate that lactate is preferentially used by neurons. They demonstrate that lactate supports neuronal sodium homeostasis and rescues the effects of glial poisoning by sodium-fluoroacetate. Altogether, they are in line with the proposed transfer of lactate from astrocytes to neurons, the so-called astrocyte-neuron-lactate shuttle.
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Affiliation(s)
- Claudia Karus
- a Institute of Neurobiology; Faculty of Mathematics and Natural Sciences; Heinrich Heine University Düsseldorf ; Düsseldorf , Germany
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Blanco AM, Gómez-Boronat M, Pérez-Maceira J, Mancebo MJ, Aldegunde M. Brain glycogen supercompensation after different conditions of induced hypoglycemia and sustained swimming in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol A Mol Integr Physiol 2015; 187:55-60. [PMID: 25956213 DOI: 10.1016/j.cbpa.2015.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 11/17/2022]
Abstract
Brain glycogen is depleted when used as an emergency energy substrate. In mammals, brain glycogen levels rebound to higher than normal levels after a hypoglycemic episode and a few hours after refeeding or administration of glucose. This phenomenon is called glycogen supercompensation. However, this mechanism has not been investigated in lower vertebrates. The aim of this study was therefore to determine whether brain glycogen supercompensation occurs in the rainbow trout brain. For this purpose, short-term brain glucose and glycogen contents were determined in rainbow trout after being subjected to the following experimental conditions: i) a 5-day or 10-day fasting period and refeeding; ii) a single injection of insulin (4 mg kg(-1)) and refeeding; and iii) sustained swimming and injection of glucose (500 mg kg(-1)). Food deprivation during the fasting periods and insulin administration both induced a decrease in glucose and glycogen levels in the brain. However, only refeeding after 10 days of fasting significantly increased the brain glycogen content above control levels, in a clear short-term supercompensation response. Unlike in mammals, prolonged exercise did not alter brain glucose or glycogen levels. Furthermore, brain glycogen supercompensation was not observed after glucose administration in fish undergoing sustained swimming. To our knowledge, this is the first study providing direct experimental evidence for the existence of a short-term glycogen supercompensation response in a teleost brain, although the response was only detectable after prolonged fasting.
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Affiliation(s)
- A M Blanco
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M Gómez-Boronat
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - J Pérez-Maceira
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M J Mancebo
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M Aldegunde
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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Baltan S. Can lactate serve as an energy substrate for axons in good times and in bad, in sickness and in health? Metab Brain Dis 2015; 30:25-30. [PMID: 25034458 PMCID: PMC4297510 DOI: 10.1007/s11011-014-9595-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/10/2014] [Indexed: 11/26/2022]
Abstract
In the mammalian white matter, glycogen-derived lactate from astrocytes plays a critical role in supporting axon function using the astrocyte-neuron lactate transfer shuttle (ANLTS) system with specialized monocarboxylate transporters (MCTs). A rapid breakdown of glycogen to lactate during increased neuronal activity or low glucose conditions becomes essential to maintain axon function. Therefore astrocytes actively regulate their glycogen stores with respect to ambient glucose levels such that high ambient glucose upregulates glycogen and low levels of glucose depletes glycogen stores. Although lactate fully supports axon function in the absence of glucose and becomes a preferred energy metabolite when axons discharge at high frequency, it fails to benefit axon function during an ischemic episode in white matter. Emerging evidence implies a similar lactate transport system between oligodendrocytes and the axons they myelinate, suggesting another metabolic coupling pathway in white matter. Therefore the conditions that activate this lactate shuttle system and the signaling mechanisms that mediate activation of this system are of great interest. Future studies are expected to unravel the details of oligodendrocyte-axon lactate metabolic coupling to establish how white matter components metabolically cooperate and that lactate may be the universal metabolite to sustain CNS function.
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Affiliation(s)
- Selva Baltan
- Department of Neurosciences, Lerner Research Institute, NC/30, The Cleveland Clinic Foundation, Cleveland, OH, 44195, USA,
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44
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Affiliation(s)
- Raymond A Swanson
- Department of Neurology, University of California, San Francisco, CA, 94143, USA,
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45
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Sickmann HM, Waagepetersen HS. Effects of diabetes on brain metabolism--is brain glycogen a significant player? Metab Brain Dis 2015; 30:335-43. [PMID: 24771109 DOI: 10.1007/s11011-014-9546-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
Brain glycogen, being an intracellular glucose reservoir, contributes to maintain energy and neurotransmitter homeostasis under physiological as well as pathological conditions. Under conditions with a disturbance in systemic glucose metabolism such as in diabetes, the supply of glucose to the brain may be affected and have important impacts on brain metabolism and neurotransmission. This also implies that brain glycogen may serve an essential role in the diabetic state to sustain appropriate brain function. There are two main types of diabetes; type 1 and type 2 diabetes and both types may be associated with brain impairments e.g. cognitive decline and dementia. It is however, not clear how these impairments on brain function are linked to alterations in brain energy and neurotransmitter metabolism. In this review, we will illuminate how rodent diabetes models have contributed to a better understanding of how brain energy and neurotransmitter metabolism is affected in diabetes. There will be a particular focus on the role of brain glycogen to support glycolytic and TCA cycle activity as well as glutamate-glutamine cycle in type 1 and type 2 diabetes.
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Affiliation(s)
- Helle M Sickmann
- Dept. of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark,
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Holmes AP, Turner PJ, Carter P, Leadbeater W, Ray CJ, Hauton D, Buckler KJ, Kumar P. Glycogen metabolism protects against metabolic insult to preserve carotid body function during glucose deprivation. J Physiol 2014; 592:4493-506. [PMID: 25063821 PMCID: PMC4287740 DOI: 10.1113/jphysiol.2014.276105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023] Open
Abstract
The view that the carotid body (CB) type I cells are direct physiological sensors of hypoglycaemia is challenged by the finding that the basal sensory neuronal outflow from the whole organ is unchanged in response to low glucose. The reason for this difference in viewpoint and how the whole CB maintains its metabolic integrity when exposed to low glucose is unknown. Here we show that, in the intact superfused rat CB, basal sensory neuronal activity was sustained during glucose deprivation for 29.1 ± 1.2 min, before irreversible failure following a brief period of excitation. Graded increases in the basal discharge induced by reducing the superfusate PO2 led to proportional decreases in the time to the pre-failure excitation during glucose deprivation which was dependent on a complete run-down in glycolysis and a fall in cellular energy status. A similar ability to withstand prolonged glucose deprivation was observed in isolated type I cells. Electron micrographs and immunofluorescence staining of rat CB sections revealed the presence of glycogen granules and the glycogen conversion enzymes glycogen synthase I and glycogen phosphorylase BB, dispersed throughout the type I cell cytoplasm. Furthermore, pharmacological attenuation of glycogenolysis and functional depletion of glycogen both significantly reduced the time to glycolytic run-down by ∼33 and 65%, respectively. These findings suggest that type I cell glycogen metabolism allows for the continuation of glycolysis and the maintenance of CB sensory neuronal output in periods of restricted glucose delivery and this may act as a key protective mechanism for the organ during hypoglycaemia. The ability, or otherwise, to preserve energetic status may thus account for variation in the reported capacity of the CB to sense physiological glucose concentrations and may even underlie its function during pathological states associated with augmented CB discharge.
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Affiliation(s)
- Andrew P Holmes
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Philip J Turner
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Paul Carter
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Wendy Leadbeater
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Clare J Ray
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - David Hauton
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Keith J Buckler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Prem Kumar
- School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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Czech-Damal N, Geiseler S, Hoff M, Schliep R, Ramirez JM, Folkow L, Burmester T. The role of glycogen, glucose and lactate in neuronal activity during hypoxia in the hooded seal (Cystophora cristata) brain. Neuroscience 2014; 275:374-83. [DOI: 10.1016/j.neuroscience.2014.06.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/11/2014] [Accepted: 06/12/2014] [Indexed: 10/25/2022]
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Pfeiffer-Guglielmi B, Dombert B, Jablonka S, Hausherr V, van Thriel C, Schöbel N, Jansen RP. Axonal and dendritic localization of mRNAs for glycogen-metabolizing enzymes in cultured rodent neurons. BMC Neurosci 2014; 15:70. [PMID: 24898526 PMCID: PMC4079165 DOI: 10.1186/1471-2202-15-70] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/30/2014] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Localization of mRNAs encoding cytoskeletal or signaling proteins to neuronal processes is known to contribute to axon growth, synaptic differentiation and plasticity. In addition, a still increasing spectrum of mRNAs has been demonstrated to be localized under different conditions and developing stages thus reflecting a highly regulated mechanism and a role of mRNA localization in a broad range of cellular processes. RESULTS Applying fluorescence in-situ-hybridization with specific riboprobes on cultured neurons and nervous tissue sections, we investigated whether the mRNAs for two metabolic enzymes, namely glycogen synthase (GS) and glycogen phosphorylase (GP), the key enzymes of glycogen metabolism, may also be targeted to neuronal processes. If it were so, this might contribute to clarify the so far enigmatic role of neuronal glycogen. We found that the mRNAs for both enzymes are localized to axonal and dendritic processes in cultured lumbar spinal motoneurons, but not in cultured trigeminal neurons. In cultured cortical neurons which do not store glycogen but nevertheless express glycogen synthase, the GS mRNA is also subject to axonal and dendritic localization. In spinal motoneurons and trigeminal neurons in situ, however, the mRNAs could only be demonstrated in the neuronal somata but not in the nerves. CONCLUSIONS We could demonstrate that the mRNAs for major enzymes of neural energy metabolism can be localized to neuronal processes. The heterogeneous pattern of mRNA localization in different culture types and developmental stages stresses that mRNA localization is a versatile mechanism for the fine-tuning of cellular events. Our findings suggest that mRNA localization for enzymes of glycogen metabolism could allow adaptation to spatial and temporal energy demands in neuronal events like growth, repair and synaptic transmission.
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Affiliation(s)
- Brigitte Pfeiffer-Guglielmi
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany
| | - Benjamin Dombert
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
| | - Sibylle Jablonka
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
| | - Vanessa Hausherr
- Leibniz Research Center for Working Environment and Human Factors, Dortmund, Germany
| | - Christoph van Thriel
- Leibniz Research Center for Working Environment and Human Factors, Dortmund, Germany
| | - Nicole Schöbel
- Department of Cell Physiology, University of Bochum, Bochum, Germany
| | - Ralf-Peter Jansen
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany
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Vardjan N, Kreft M, Zorec R. Regulated Exocytosis in Astrocytes is as Slow as the Metabolic Availability of Gliotransmitters: Focus on Glutamate and ATP. GLUTAMATE AND ATP AT THE INTERFACE OF METABOLISM AND SIGNALING IN THE BRAIN 2014; 11:81-101. [DOI: 10.1007/978-3-319-08894-5_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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50
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Gliopreventive effects of guanosine against glucose deprivation in vitro. Purinergic Signal 2013; 9:643-54. [PMID: 23846842 DOI: 10.1007/s11302-013-9377-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/27/2013] [Indexed: 10/26/2022] Open
Abstract
Guanosine, a guanine-based purine, is recognized as an extracellular signaling molecule that is released from astrocytes and confers neuroprotective effects in several in vivo and in vitro studies. Astrocytes regulate glucose metabolism, glutamate transport, and defense mechanism against oxidative stress. C6 astroglial cells are widely used as an astrocyte-like cell line to study the astrocytic function and signaling pathways. Our previous studies showed that guanosine modulates the glutamate uptake activity, thus avoiding glutamatergic excitotoxicity and protecting neural cells. The goal of this study was to determine the gliopreventive effects of guanosine against glucose deprivation in vitro in cultured C6 cells. Glucose deprivation induced cytotoxicity, an increase in reactive oxygen and nitrogen species (ROS/RNS) levels and lipid peroxidation as well as affected the metabolism of glutamate, which may impair important astrocytic functions. Guanosine prevented glucose deprivation-induced toxicity in C6 cells by modulating oxidative and nitrosative stress and glial responses, such as the glutamate uptake, the glutamine synthetase activity, and the glutathione levels. Glucose deprivation decreased the level of EAAC1, the main glutamate transporter present in C6 cells. Guanosine also prevented this effect, most likely through PKC, PI3K, p38 MAPK, and ERK signaling pathways. Taken together, these results show that guanosine may represent an important mechanism for protection of glial cells against glucose deprivation. Additionally, this study contributes to a more thorough understanding of the glial- and redox-related protective properties of guanosine in astroglial cells.
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