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Naveed M, Smedlund K, Zhou QG, Cai W, Hill JW. Astrocyte involvement in metabolic regulation and disease. Trends Endocrinol Metab 2024:S1043-2760(24)00220-0. [PMID: 39214743 DOI: 10.1016/j.tem.2024.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 07/30/2024] [Accepted: 08/02/2024] [Indexed: 09/04/2024]
Abstract
Astrocytes, the predominant glial cell type in the mammalian brain, influence a wide variety of brain parameters including neuronal energy metabolism. Exciting recent studies have shown that obesity and diabetes can impact on astrocyte function. We review evidence that dysregulation of astrocytic lipid metabolism and glucose sensing contributes to dysregulation of whole-body energy balance, thermoregulation, and insulin sensitivity. In addition, we consider the overlooked topic of the sex-specific roles of astrocytes and their response to hormonal fluctuations that provide insights into sex differences in metabolic regulation. Finally, we provide an update on potential ways to manipulate astrocyte function, including genetic targeting, optogenetic and chemogenetic techniques, transplantation, and tailored exosome-based therapies, which may lead to improved treatments for metabolic disease.
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Affiliation(s)
- Muhammad Naveed
- Department of Physiology and Pharmacology, School of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Kathryn Smedlund
- Department of Physiology and Pharmacology, School of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Qi-Gang Zhou
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, China
| | - Weikang Cai
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY, USA
| | - Jennifer W Hill
- Department of Physiology and Pharmacology, School of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA; Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, USA.
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Barahona MJ, Ferrada L, Vera M, Nualart F. Tanycytes release glucose using the glucose-6-phosphatase system during hypoglycemia to control hypothalamic energy balance. Mol Metab 2024; 84:101940. [PMID: 38641253 PMCID: PMC11060961 DOI: 10.1016/j.molmet.2024.101940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 04/21/2024] Open
Abstract
OBJECTIVE The liver releases glucose into the blood using the glucose-6-phosphatase (G6Pase) system, a multiprotein complex located in the endoplasmic reticulum (ER). Here, we show for the first time that the G6Pase system is also expressed in hypothalamic tanycytes, and it is required to regulate energy balance. METHODS Using automatized qRT-PCR and immunohistochemical analyses, we evaluated the expression of the G6Pase system. Fluorescent glucose analogue (2-NBDG) uptake was evaluated by 4D live-cell microscopy. Glucose release was tested using a glucose detection kit and high-content live-cell analysis instrument, Incucyte s3. In vivo G6pt knockdown in tanycytes was performed by AAV1-shG6PT-mCherry intracerebroventricular injection. Body weight gain, adipose tissue weight, food intake, glucose metabolism, c-Fos, and neuropeptide expression were evaluated at 4 weeks post-transduction. RESULTS Tanycytes sequester glucose-6-phosphate (G6P) into the ER through the G6Pase system and release glucose in hypoglycaemia via facilitative glucose transporters (GLUTs). Strikingly, in vivo tanycytic G6pt knockdown has a powerful peripheral anabolic effect observed through decreased body weight, white adipose tissue (WAT) tissue mass, and strong downregulation of lipogenesis genes. Selective deletion of G6pt in tanycytes also decreases food intake, c-Fos expression in the arcuate nucleus (ARC), and Npy mRNA expression in fasted mice. CONCLUSIONS The tanycyte-associated G6Pase system is a central mechanism involved in controlling metabolism and energy balance.
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Affiliation(s)
- María José Barahona
- Laboratory of Neurobiology and Stem Cells, NeuroCellT, Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile; Center for Advanced Microscopy CMA BIO BIO, University of Concepcion, Concepcion, Chile; Laboratory of Appetite Physiology (FIDELA), Faculty of Medicine and Sciences, University San Sebastián, Concepción Campus, Concepción, Chile
| | - Luciano Ferrada
- Center for Advanced Microscopy CMA BIO BIO, University of Concepcion, Concepcion, Chile
| | - Matías Vera
- Laboratory of Neurobiology and Stem Cells, NeuroCellT, Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile; Center for Advanced Microscopy CMA BIO BIO, University of Concepcion, Concepcion, Chile
| | - Francisco Nualart
- Laboratory of Neurobiology and Stem Cells, NeuroCellT, Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile; Center for Advanced Microscopy CMA BIO BIO, University of Concepcion, Concepcion, Chile.
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Dienel GA, Schousboe A, McKenna MC, Rothman DL. A tribute to Leif Hertz: The historical context of his pioneering studies of the roles of astrocytes in brain energy metabolism, neurotransmission, cognitive functions, and pharmacology identifies important, unresolved topics for future studies. J Neurochem 2024; 168:461-495. [PMID: 36928655 DOI: 10.1111/jnc.15812] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
Leif Hertz, M.D., D.Sc. (honōris causā) (1930-2018), was one of the original and noteworthy participants in the International Conference on Brain Energy Metabolism (ICBEM) series since its inception in 1993. The biennial ICBEM conferences are organized by neuroscientists interested in energetics and metabolism underlying neural functions; they have had a high impact on conceptual and experimental advances in these fields and on promoting collaborative interactions among neuroscientists. Leif made major contributions to ICBEM discussions and understanding of metabolic and signaling characteristics of astrocytes and their roles in brain function. His studies ranged from uptake of K+ from extracellular fluid and its stimulation of astrocytic respiration, identification, and regulation of enzymes specifically or preferentially expressed in astrocytes in the glutamate-glutamine cycle of excitatory neurotransmission, a requirement for astrocytic glycogenolysis for fueling K+ uptake, involvement of glycogen in memory consolidation in the chick, and pharmacology of astrocytes. This tribute to Leif Hertz highlights his major discoveries, the high impact of his work on astrocyte-neuron interactions, and his unparalleled influence on understanding the cellular basis of brain energy metabolism. His work over six decades has helped integrate the roles of astrocytes into neurotransmission where oxidative and glycogenolytic metabolism during neurotransmitter glutamate turnover are key aspects of astrocytic energetics. Leif recognized that brain astrocytic metabolism is greatly underestimated unless the volume fraction of astrocytes is taken into account. Adjustment for pathway rates expressed per gram tissue for volume fraction indicates that astrocytes have much higher oxidative rates than neurons and astrocytic glycogen concentrations and glycogenolytic rates during sensory stimulation in vivo are similar to those in resting and exercising muscle, respectively. These novel insights are typical of Leif's astute contributions to the energy metabolism field, and his publications have identified unresolved topics that provide the neuroscience community with challenges and opportunities for future research.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, 21201, USA
| | - Douglas L Rothman
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, 06520, USA
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Siddique AHH, Kale PP. Importance of glucose and its metabolism in neurodegenerative disorder, as well as the combination of multiple therapeutic strategies targeting α-synuclein and neuroprotection in the treatment of Parkinson's disease. Rev Neurol (Paris) 2023:S0035-3787(23)01066-4. [PMID: 38040547 DOI: 10.1016/j.neurol.2023.08.011] [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: 01/18/2022] [Revised: 04/04/2023] [Accepted: 08/18/2023] [Indexed: 12/03/2023]
Abstract
According to recent findings, Phosphoglycerate Kinase 1 (pgk-1) enzyme is linked to Parkinson's disease (PD). Mutations in the PGK-1 gene lead to decreases in the pgk-1 enzyme which causes an imbalance in the levels of energy demand and supply. An increase in glycolytic adenosine triphosphate (ATP) production would help alleviate energy deficiency and sustain the acute energetic need of neurons. Neurodegeneration is caused by an imbalance or reduction in ATP levels. Recent data suggest that medications that increase glycolysis and neuroprotection can be used to treat PD. The current study focuses on treatment options for disorders associated with the pgk-1 enzyme, GLP-1, and A2A receptor which can be utilized to treat PD. A combination of metformin and terazosin, exenatide and meclizine, istradefylline and salbutamol treatments may benefit parkinsonism. The review also looked at potential target-specific new techniques that might assist in satisfying unfulfilled requirements in the treatment of PD.
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Affiliation(s)
- A H H Siddique
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, V. L. Mehta Road, Vile Parle west, 400056 Mumbai, India.
| | - P P Kale
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, V. L. Mehta Road, Vile Parle west, 400056 Mumbai, India.
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Jing D, Hou X, Guo X, Zhao X, Zhang K, Zhang J, Kan C, Han F, Liu J, Sun X. Astrocytes in Post-Stroke Depression: Roles in Inflammation, Neurotransmission, and Neurotrophin Signaling. Cell Mol Neurobiol 2023; 43:3301-3313. [PMID: 37470888 DOI: 10.1007/s10571-023-01386-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/30/2023] [Indexed: 07/21/2023]
Abstract
Post-stroke depression (PSD) is a frequent and disabling complication of stroke that affects up to one-third of stroke survivors. The pathophysiology of PSD involves multiple mechanisms, including neurochemical, neuroinflammatory, neurotrophic, and neuroplastic changes. Astrocytes are a type of glial cell that is plentiful and adaptable in the central nervous system. They play key roles in various mechanisms by modulating neurotransmission, inflammation, neurogenesis, and synaptic plasticity. This review summarizes the latest evidence of astrocyte involvement in PSD from human and animal studies, focusing on the alterations of astrocyte markers and functions in relation to monoamine neurotransmitters, inflammatory cytokines, brain-derived neurotrophic factor, and glutamate excitotoxicity. We also discuss the potential therapeutic implications of targeting astrocytes for PSD prevention and treatment. Astrocytes could be new candidates for antidepressant medications and other interventions that aim to restore astrocyte homeostasis and function in PSD. Astrocytes could be new candidates for antidepressant medications and other interventions that aim to restore astrocyte homeostasis and function in PSD.
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Affiliation(s)
- Dongqing Jing
- Department of Neurology 1, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
| | - Xiaoli Hou
- Department of General Practice, Weifang Sixth People's Hospital, Weifang, China
| | - Xiao Guo
- Department of Neurology 1, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
| | - Xin Zhao
- Department of Neurology 1, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
| | - Kexin Zhang
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
- Department of Endocrinology and Metabolism, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
| | - Jingwen Zhang
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
- Department of Endocrinology and Metabolism, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
| | - Chengxia Kan
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China
- Department of Endocrinology and Metabolism, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China
| | - Fang Han
- Department of Pathology, Affiliated Hospital of Weifang Medical University, Weifang, China
| | - Junling Liu
- Department of Neurology 1, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China.
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China.
| | - Xiaodong Sun
- Clinical Research Center, Affiliated Hospital of Weifang Medical University, Weifang, China.
- Department of Endocrinology and Metabolism, Affiliated Hospital of Weifang Medical University, 2428 Yuhe Road, Weifang, 261031, China.
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Jurcau A, Andronie-Cioara FL, Nistor-Cseppento DC, Pascalau N, Rus M, Vasca E, Jurcau MC. The Involvement of Neuroinflammation in the Onset and Progression of Parkinson's Disease. Int J Mol Sci 2023; 24:14582. [PMID: 37834030 PMCID: PMC10573049 DOI: 10.3390/ijms241914582] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/22/2023] [Accepted: 09/24/2023] [Indexed: 10/15/2023] Open
Abstract
Parkinson's disease is a neurodegenerative disease exhibiting the fastest growth in incidence in recent years. As with most neurodegenerative diseases, the pathophysiology is incompletely elucidated, but compelling evidence implicates inflammation, both in the central nervous system and in the periphery, in the initiation and progression of the disease, although it is not yet clear what triggers this inflammatory response and where it begins. Gut dysbiosis seems to be a likely candidate for the initiation of the systemic inflammation. The therapies in current use provide only symptomatic relief, but do not interfere with the disease progression. Nonetheless, animal models have shown promising results with therapies that target various vicious neuroinflammatory cascades. Translating these therapeutic strategies into clinical trials is still in its infancy, and a series of issues, such as the exact timing, identifying biomarkers able to identify Parkinson's disease in early and pre-symptomatic stages, or the proper indications of genetic testing in the population at large, will need to be settled in future guidelines.
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Affiliation(s)
- Anamaria Jurcau
- Department of Psycho-Neuroscience and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania; (A.J.); (D.C.N.-C.)
| | - Felicia Liana Andronie-Cioara
- Department of Psycho-Neuroscience and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania; (A.J.); (D.C.N.-C.)
| | - Delia Carmen Nistor-Cseppento
- Department of Psycho-Neuroscience and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania; (A.J.); (D.C.N.-C.)
| | - Nicoleta Pascalau
- Department of Psycho-Neuroscience and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania; (A.J.); (D.C.N.-C.)
| | - Marius Rus
- Department of Medical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, 410087 Oradea, Romania
| | - Elisabeta Vasca
- Department of Oral Rehabilitation, Faculty of Medicine “Vasile Goldis” Arad, 310025 Arad, Romania
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Early Diagnosis of Murine Sepsis-Associated Encephalopathy Using Dynamic PET/CT Imaging and Multiparametric MRI. Mol Imaging Biol 2022; 24:928-939. [PMID: 35612771 DOI: 10.1007/s11307-022-01743-z] [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: 04/06/2022] [Revised: 05/06/2022] [Accepted: 05/13/2022] [Indexed: 12/29/2022]
Abstract
PURPOSE Early diagnosis of sepsis-associated encephalopathy (SAE) is essential for the treatment and prognosis of septic patients. Static PET and MRI have shown promise for early diagnosis, while pharmacokinetic parameters from dynamic PET may provide better quantification for SAE. This study aims to compare the performance of dynamic 2-deoxy-2-[18F]fluoro-D-glucose ([18F]F-FDG) PET and multiparametric MRI in early imaging SAE with a view to providing guidance for the early diagnosis of SAE. PROCEDURES Dynamic [18F]F-FDG-PET/CT scans and multiparametric MRI were performed in SAE mice induced by LPS. Standardized uptake value (SUV) was measured in static scan images and [18F]F-FDG pharmacokinetic parameters were analyzed with two-tissue compartment model and Patlak plot. MRI relative signal intensity (rT1) derived from T1-weighted images (pre and post contrast) and 4 parameters originating from diffusion-weighted data were measured. RESULTS Both SUV and dephosphorylation rate constant (k4) increased in SAE model as early as 6 h post sepsis induction, while k4 increased with the relative value (SAE/normal) significantly stronger than that of SUV. Moreover, the net influx constant (Ki) showed significant decrease in SAE as early as 6 h compared with normal mice. Increased signal intensity was identified in T1-weighted contrast enhanced images and rT1 value increased at 12 h post induction. Diffusion tensor imaging (DTI) revealed fractional anisotropy (FA) decreased at 12 h and 24 h in external capsule (ec) and declined axial diffusivity (AD) was shown in white matter at 24 h. CONCLUSIONS The dynamic PET (k4) was more sensitive than static PET (SUV) for early diagnosis of SAE and declined Ki was firstly found in murine SAE, which indicated the advantage of dynamic PET/CT in early detection and differential diagnosis of SAE. While MRI has a higher soft tissue resolution than PET/CT and can classify more subtle brain areas, the comprehensive utilization of the two modalities is helpful for managing SAE.
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Wang Q, Duan L, Li X, Wang Y, Guo W, Guan F, Ma S. Glucose Metabolism, Neural Cell Senescence and Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms23084351. [PMID: 35457168 PMCID: PMC9030802 DOI: 10.3390/ijms23084351] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/05/2022] [Accepted: 04/12/2022] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD), an elderly neurodegenerative disorder with a high incidence and progressive memory decline, is one of the most expensive, lethal, and burdening diseases. To date, the pathogenesis of AD has not been fully illustrated. Emerging studies have revealed that cellular senescence and abnormal glucose metabolism in the brain are the early hallmarks of AD. Moreover, cellular senescence and glucose metabolism disturbance in the brain of AD patients may precede amyloid-β deposition or Tau protein phosphorylation. Thus, metabolic reprogramming targeting senescent microglia and astrocytes may be a novel strategy for AD intervention and treatment. Here, we recapitulate the relationships between neural cell senescence and abnormal glucose metabolism (e.g., insulin signaling, glucose and lactate metabolism) in AD. We then discuss the potential perspective of metabolic reprogramming towards an AD intervention, providing a theoretical basis for the further exploration of the pathogenesis of and therapeutic approach toward AD.
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Affiliation(s)
- Qianqian Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
| | - Linyan Duan
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
| | - Xingfan Li
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
| | - Yifu Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
| | - Wenna Guo
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
| | - Fangxia Guan
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
- Institute of Neuroscience, Zhengzhou University, Zhengzhou 450052, China
- NHC Key Laboratory of Birth Defects Prevention, Henan Institute of Reproduction Health Science and Technology, Zhengzhou 450002, China
- Correspondence: (F.G.); (S.M.)
| | - Shanshan Ma
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China; (Q.W.); (L.D.); (X.L.); (Y.W.); (W.G.)
- Institute of Neuroscience, Zhengzhou University, Zhengzhou 450052, China
- NHC Key Laboratory of Birth Defects Prevention, Henan Institute of Reproduction Health Science and Technology, Zhengzhou 450002, China
- Correspondence: (F.G.); (S.M.)
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Takahashi S. Metabolic Contribution and Cerebral Blood Flow Regulation by Astrocytes in the Neurovascular Unit. Cells 2022; 11:cells11050813. [PMID: 35269435 PMCID: PMC8909328 DOI: 10.3390/cells11050813] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 12/10/2022] Open
Abstract
The neurovascular unit (NVU) is a conceptual framework that has been proposed to better explain the relationships between the neural cells and blood vessels in the human brain, focused mainly on the brain gray matter. The major components of the NVU are the neurons, astrocytes (astroglia), microvessels, pericytes, and microglia. In addition, we believe that oligodendrocytes should also be included as an indispensable component of the NVU in the white matter. Of all these components, astrocytes in particular have attracted the interest of researchers because of their unique anatomical location; these cells are interposed between the neurons and the microvessels of the brain. Their location suggests that astrocytes might regulate the cerebral blood flow (CBF) in response to neuronal activity, so as to ensure an adequate supply of glucose and oxygen to meet the metabolic demands of the neurons. In fact, the adult human brain, which accounts for only 2% of the entire body weight, consumes approximately 20–25% of the total amount of glucose and oxygen consumed by the whole body. The brain needs a continuous supply of these essential energy sources through the CBF, because there are practically no stores of glucose or oxygen in the brain; both acute and chronic cessation of CBF can adversely affect brain functions. In addition, another important putative function of the NVU is the elimination of heat and waste materials produced by neuronal activity. Recent evidence suggests that astrocytes play pivotal roles not only in supplying glucose, but also fatty acids and amino acids to neurons. Loss of astrocytic support can be expected to lead to malfunction of the NVU as a whole, which underlies numerous neurological disorders. In this review, we shall focus on historical and recent findings with regard to the metabolic contributions of astrocytes in the NVU.
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Affiliation(s)
- Shinichi Takahashi
- Department of Neurology and Stroke, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-shi 350-1298, Japan; ; Tel.: +81-42-984-4111 (ext. 7412) or +81-3-3353-1211 (ext. 62613); Fax: +81-42-984-0664 or +81-3-3357-5445
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Takahashi S, Mashima K. Neuroprotection and Disease Modification by Astrocytes and Microglia in Parkinson Disease. Antioxidants (Basel) 2022; 11:antiox11010170. [PMID: 35052674 PMCID: PMC8773262 DOI: 10.3390/antiox11010170] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/03/2022] [Accepted: 01/13/2022] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress and neuroinflammation are common bases for disease onset and progression in many neurodegenerative diseases. In Parkinson disease, which is characterized by the degeneration of dopaminergic neurons resulting in dopamine depletion, the pathogenesis differs between hereditary and solitary disease forms and is often unclear. In addition to the pathogenicity of alpha-synuclein as a pathological disease marker, the involvement of dopamine itself and its interactions with glial cells (astrocyte or microglia) have attracted attention. Pacemaking activity, which is a hallmark of dopaminergic neurons, is essential for the homeostatic maintenance of adequate dopamine concentrations in the synaptic cleft, but it imposes a burden on mitochondrial oxidative glucose metabolism, leading to reactive oxygen species production. Astrocytes provide endogenous neuroprotection to the brain by producing and releasing antioxidants in response to oxidative stress. Additionally, the protective function of astrocytes can be modified by microglia. Some types of microglia themselves are thought to exacerbate Parkinson disease by releasing pro-inflammatory factors (M1 microglia). Although these inflammatory microglia may further trigger the inflammatory conversion of astrocytes, microglia may induce astrocytic neuroprotective effects (A2 astrocytes) simultaneously. Interestingly, both astrocytes and microglia express dopamine receptors, which are upregulated in the presence of neuroinflammation. The anti-inflammatory effects of dopamine receptor stimulation are also attracting attention because the functions of astrocytes and microglia are greatly affected by both dopamine depletion and therapeutic dopamine replacement in Parkinson disease. In this review article, we will focus on the antioxidative and anti-inflammatory effects of astrocytes and their synergism with microglia and dopamine.
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Affiliation(s)
- Shinichi Takahashi
- Department of Neurology and Stroke, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-shi 350-1298, Japan
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan;
- Correspondence: ; Tel.: +81-42-984-4111 (ext. 7412); Fax: +81-42-984-0664
| | - Kyoko Mashima
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan;
- Department of Neurology, Tokyo Saiseikai Central Hospital, 1-4-17 Mita, Minato-ku, Tokyo 108-0073, Japan
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Neuroprotective Function of High Glycolytic Activity in Astrocytes: Common Roles in Stroke and Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22126568. [PMID: 34207355 PMCID: PMC8234992 DOI: 10.3390/ijms22126568] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 12/21/2022] Open
Abstract
Astrocytes (also, astroglia) consume huge amounts of glucose and produce lactate regardless of sufficient oxygen availability, indicating a high capacity for aerobic glycolysis. Glycolysis in astrocytes is activated in accordance with neuronal excitation and leads to increases in the release of lactate from astrocytes. Although the fate of this lactate remains somewhat controversial, it is believed to fuel neurons as an energy substrate. Besides providing lactate, astrocytic glycolysis plays an important role in neuroprotection. Among the minor pathways of glucose metabolism, glucose flux to the pentose-phosphate pathway (PPP), a major shunt pathway of glycolysis, is attracting research interest. In fact, PPP activity in astrocytes is five to seven times higher than that in neurons. The astrocytic PPP plays a key role in protecting neurons against oxidative stress by providing neurons with a reduced form of glutathione, which is necessary to eliminate reactive oxygen species. Therefore, enhancing astrocytic glycolysis might promote neuronal protection during acute ischemic stroke. Contrariwise, the dysfunction of astrocytic glycolysis and the PPP have been implicated in the pathogenesis of various neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis, since mitochondrial dysfunction and oxidative stress trigger and accelerate disease progression.
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Zhang S, Lachance BB, Mattson MP, Jia X. Glucose metabolic crosstalk and regulation in brain function and diseases. Prog Neurobiol 2021; 204:102089. [PMID: 34118354 DOI: 10.1016/j.pneurobio.2021.102089] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/08/2021] [Accepted: 06/01/2021] [Indexed: 01/11/2023]
Abstract
Brain glucose metabolism, including glycolysis, the pentose phosphate pathway, and glycogen turnover, produces ATP for energetic support and provides the precursors for the synthesis of biological macromolecules. Although glucose metabolism in neurons and astrocytes has been extensively studied, the glucose metabolism of microglia and oligodendrocytes, and their interactions with neurons and astrocytes, remain critical to understand brain function. Brain regions with heterogeneous cell composition and cell-type-specific profiles of glucose metabolism suggest that metabolic networks within the brain are complex. Signal transduction proteins including those in the Wnt, GSK-3β, PI3K-AKT, and AMPK pathways are involved in regulating these networks. Additionally, glycolytic enzymes and metabolites, such as hexokinase 2, acetyl-CoA, and enolase 2, are implicated in the modulation of cellular function, microglial activation, glycation, and acetylation of biomolecules. Given these extensive networks, glucose metabolism dysfunction in the whole brain or specific cell types is strongly associated with neurologic pathology including ischemic brain injury and neurodegenerative disorders. This review characterizes the glucose metabolism networks of the brain based on molecular signaling and cellular and regional interactions, and elucidates glucose metabolism-based mechanisms of neurological diseases and therapeutic approaches that may ameliorate metabolic abnormalities in those diseases.
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Affiliation(s)
- Shuai Zhang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, United States
| | - Brittany Bolduc Lachance
- Program in Trauma, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States
| | - Mark P Mattson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States.
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Chowdhury HH. Differences in cytosolic glucose dynamics in astrocytes and adipocytes measured by FRET-based nanosensors. Biophys Chem 2020; 261:106377. [PMID: 32302866 DOI: 10.1016/j.bpc.2020.106377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 11/17/2022]
Abstract
The cellular response to fluctuations in blood glucose levels consists of integrative regulation of cell glucose uptake and glucose utilization in the cytosol, resulting in altered levels of glucose in the cytosol. Cytosolic glucose is difficult to be measured in the intact tissue, however recently methods have become available that allow measurements of glucose in single living cells with fluorescence resonance energy transfer (FRET) based protein sensors. By studying the dynamics of cytosolic glucose levels in different experimental settings, we can gain insights into the properties of plasma membrane permeability to glucose and glucose utilization in the cytosol, and how these processes are modulated by different environmental conditions, agents and enzymes. In this review, we compare the cytosolic regulation of glucose in adipocytes and astrocytes - two important regulators of energy balance and glucose homeostasis in whole body and brain, respectively, with particular emphasis on the data obtained with FRET based protein sensors as well as other biochemical and molecular approaches.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, 1000 Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
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Takahashi S. Metabolic compartmentalization between astroglia and neurons in physiological and pathophysiological conditions of the neurovascular unit. Neuropathology 2020; 40:121-137. [PMID: 32037635 PMCID: PMC7187297 DOI: 10.1111/neup.12639] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 12/17/2022]
Abstract
Astroglia or astrocytes, the most abundant cells in the brain, are interposed between neuronal synapses and microvasculature in the brain gray matter. They play a pivotal role in brain metabolism as well as in the regulation of cerebral blood flow, taking advantage of their unique anatomical location. In particular, the astroglial cellular metabolic compartment exerts supportive roles in dedicating neurons to the generation of action potentials and protects them against oxidative stress associated with their high energy consumption. An impairment of normal astroglial function, therefore, can lead to numerous neurological disorders including stroke, neurodegenerative diseases, and neuroimmunological diseases, in which metabolic derangements accelerate neuronal damage. The neurovascular unit (NVU), the major components of which include neurons, microvessels, and astroglia, is a conceptual framework that was originally used to better understand the pathophysiology of cerebral ischemia. At present, the NVU is a tool for understanding normal brain physiology as well as the pathophysiology of numerous neurological disorders. The metabolic responses of astroglia in the NVU can be either protective or deleterious. This review focuses on three major metabolic compartments: (i) glucose and lactate; (ii) fatty acid and ketone bodies; and (iii) D- and L-serine. Both the beneficial and the detrimental roles of compartmentalization between neurons and astroglia will be discussed. A better understanding of the astroglial metabolic response in the NVU is expected to lead to the development of novel therapeutic strategies for diverse neurological diseases.
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Affiliation(s)
- Shinichi Takahashi
- Department of Neurology and StrokeSaitama Medical University International Medical CenterSaitamaJapan
- Department of PhysiologyKeio University School of MedicineTokyoJapan
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Nedzvetsky VS, Sukharenko EV, Baydas G, Andrievsky GV. Water-soluble C60 fullerene ameliorates astroglial reactivity and TNFa production in retina of diabetic rats. REGULATORY MECHANISMS IN BIOSYSTEMS 2019. [DOI: 10.15421/021975] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The complications of both first and second types of diabetes mellitus patients are important cause of decline in quality of life and mortality worldwide. Diabetic retinopathy (DR) is a widespread complication that affects almost 60% of patients with prolonged (at least 10–15 years) diabetes. The critical role of glial cells has been shown in retinopathy initiation in the last decades. Furthermore, glial reactivity and inflammation could be key players in early pathogenesis of DR. Despite the large amount of research data, the approaches of effective DR therapy remain unclear. The progress of DR is accompanied by pro-inflammatory and pro-oxidative changes in retinal cells including astrocytes and Muller cells. Glial reactivity is a key pathogenetic factor of various disorders in neural tissue. Fullerene C60 nanoparticles were confirmed for both antioxidant and anti-inflammatory capability. In the presented study glioprotective efficacy of water-soluble hydrated fullerene C60 (C60HyFn) was tested in a STZ-diabetes model during 12 weeks. Exposure of the STZ-diabetic rat group to C60HyFn ameliorated the astrocyte reactivity which was determined via S100β and PARP1 overexpression. Moreover, C60HyFn induced the decrease of TNFα production in the retina of STZ-diabetic rats. By contrast, the treatment with C60HyFn of the normal control rat group didn’t change the content of all abovementioned markers of astrogliosis and inflammation. Thus, diabetes-induced abnormalities in the retina were suppressed via the anti-oxidant, anti-inflammatory and glioprotective effects of C60HyFn at low doses. The presented results demonstrate that C60HyFn can ensure viability of retinal cells viability through glioprotective effect and could be a new therapeutic nano-strategy of DR treatment.
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Dienel GA. The “protected” glucose transport through the astrocytic endoplasmic reticulum is too slow to serve as a quantitatively‐important highway for nutrient delivery. J Neurosci Res 2019; 97:854-862. [DOI: 10.1002/jnr.24432] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Gerald A. Dienel
- Department of Neurology University of Arkansas for Medical Sciences Little Rock Arkansas
- Department of Cell Biology and Physiology University of New Mexico Albuquerque New Mexico
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Souza DG, Almeida RF, Souza DO, Zimmer ER. The astrocyte biochemistry. Semin Cell Dev Biol 2019; 95:142-150. [PMID: 30951895 DOI: 10.1016/j.semcdb.2019.04.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/19/2019] [Accepted: 04/01/2019] [Indexed: 02/06/2023]
Abstract
Astrocytes are a unique and dynamic subtype of glial cells in the central nervous system (CNS). Understanding their biochemical reactions and their influence in the surrounding cells is extremely important in the neuroscience field. They exert important influence in the neurotransmission, ionic homeostasis and also release neuroactive molecules termed gliotransmitters. Additionally, they metabolize, store and release metabolic substrates to meet high brain energy requirements. In this review, we highlight the main biochemical reactions regarding energy metabolism that take place in astrocytes. Special attention is given to synthesis, storage and catabolism of glucose, release of lactate, oxidation of fatty acids, production of ketone bodies, and metabolism of the main neurotransmitters, glutamate and GABA. The recent findings allow proposing these cells as key players controlling the energetic homeostasis in the CNS.
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Affiliation(s)
- Débora G Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Roberto F Almeida
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Exact and Biological Sciences Institute, Biological Sciences Department, Federal University of Ouro Preto, Ouro Preto, Brazil
| | - Diogo O Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Biochemistry, UFRGS, Porto Alegre, Brazil
| | - Eduardo R Zimmer
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Pharmacology, UFRGS, Porto Alegre, Brazil; Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil; Brain Institute of Rio Grande do Sul (BraIns), Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
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