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Olmedillas Del Moral M, Fröhlich N, Figarella K, Mojtahedi N, Garaschuk O. Effect of Caloric Restriction on the in vivo Functional Properties of Aging Microglia. Front Immunol 2020; 11:750. [PMID: 32411143 PMCID: PMC7198715 DOI: 10.3389/fimmu.2020.00750] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/02/2020] [Indexed: 12/29/2022] Open
Abstract
Throughout the lifespan, microglia, the primary innate immune cells of the brain, fulfill a plethora of homeostatic as well as active immune defense functions, and their aging-induced dysfunctionality is now considered as a key trigger of aging-related brain disorders. Recent evidence suggests that both organism’s sex and age critically impact the functional state of microglia but in vivo determinants of such state(s) remain unclear. Therefore, we analyzed in vivo the sex-specific functional states of microglia in young adult, middle aged and old wild type mice by means of multicolor two-photon imaging, using the microglial Ca2 + signaling and directed process motility as main readouts. Our data revealed the sex-specific differences in microglial Ca2 + signaling at all ages tested, beginning with young adults. Furthermore, for both sexes it showed that during the lifespan the functional state of microglia changes at least twice. Already at middle age the cells are found in the reactive or immune alerted state, characterized by heightened Ca2 + signaling but normal process motility whereas old mice harbor senescent microglia with decreased Ca2 + signaling, and faster but disorganized directed movement of microglial processes. The 6–12 months long caloric restriction (70% of ad libitum food intake) counteracted these aging-induced changes shifting many but not all functional properties of microglia toward a younger phenotype. The improvement of Ca2 + signaling was more pronounced in males. Importantly, even short-term (6-week-long) caloric restriction beginning at old age strongly improved microglial process motility and induced a significant albeit weaker improvement of microglial Ca2 + signaling. Together, these data provide first sex-specific in vivo characterization of functional properties of microglia along the lifespan and identify caloric restriction as a potent, cost-effective, and clinically relevant tool for rejuvenation of microglia.
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Affiliation(s)
- Maria Olmedillas Del Moral
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Nicole Fröhlich
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Katherine Figarella
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Nima Mojtahedi
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University Tübingen, Tübingen, Germany
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Abstract
A user-friendly workflow, termed Tomahto, enables real-time targeted pathway proteomics assays using two-dimensional multiplexing technology. Hundreds of proteins of interest from a multitude of samples can be targeted and accurately quantified in a remarkably sensitive fashion. We highlight Tomahto’s ease of use, sensitivity, and accuracy and present proof-of-principle utility by targeting 260 metabolism- and inflammation-related proteins across 90 samples (nine tissues from five old and five young mice). Tissue-specific aging effects are presented with specific interest in metabolic and inflammatory pathways of white adipose tissue. We validated our approach through comparison with a global proteome survey across the tissues, work that we also provide as a general resource for the community. Pathway proteomics strategies measure protein expression changes in specific cellular processes that carry out related functions. Using targeted tandem mass tags-based sample multiplexing, hundreds of proteins can be quantified across 10 or more samples simultaneously. To facilitate these highly complex experiments, we introduce a strategy that provides complete control over targeted sample multiplexing experiments, termed Tomahto, and present its implementation on the Orbitrap Tribrid mass spectrometer platform. Importantly, this software monitors via the external desktop computer to the data stream and inserts optimized MS2 and MS3 scans in real time based on an application programming interface with the mass spectrometer. Hundreds of proteins of interest from diverse biological samples can be targeted and accurately quantified in a sensitive and high-throughput fashion. It achieves sensitivity comparable to, if not better than, deep fractionation and requires minimal total sample input (∼10 µg). As a proof-of-principle experiment, we selected four pathways important in metabolism- and inflammation-related processes (260 proteins/520 peptides) and measured their abundance across 90 samples (nine tissues from five old and five young mice) to explore effects of aging. Tissue-specific aging is presented here and we highlight the role of inflammation- and metabolism-related processes in white adipose tissue. We validated our approach through comparison with a global proteome survey across the tissues, work that we also provide as a general resource for the community.
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53
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Microglial metabolic flexibility supports immune surveillance of the brain parenchyma. Nat Commun 2020; 11:1559. [PMID: 32214088 PMCID: PMC7096448 DOI: 10.1038/s41467-020-15267-z] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023] Open
Abstract
Microglia are highly motile cells that continuously monitor the brain environment and respond to damage-associated cues. While glucose is the main energy substrate used by neurons in the brain, the nutrients metabolized by microglia to support surveillance of the parenchyma remain unexplored. Here, we use fluorescence lifetime imaging of intracellular NAD(P)H and time-lapse two-photon imaging of microglial dynamics in vivo and in situ, to show unique aspects of the microglial metabolic signature in the brain. Microglia are metabolically flexible and can rapidly adapt to consume glutamine as an alternative metabolic fuel in the absence of glucose. During insulin-induced hypoglycemia in vivo or in aglycemia in acute brain slices, glutaminolysis supports the maintenance of microglial process motility and damage-sensing functions. This metabolic shift sustains mitochondrial metabolism and requires mTOR-dependent signaling. This remarkable plasticity allows microglia to maintain their critical surveillance and phagocytic roles, even after brain neuroenergetic homeostasis is compromised. Glucose is the main source of fuel in the brain. Here, the authors show that in the absence of glucose, glutamine is required for microglia to maintain their immune surveillance function.
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54
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Afridi R, Kim JH, Rahman MH, Suk K. Metabolic Regulation of Glial Phenotypes: Implications in Neuron-Glia Interactions and Neurological Disorders. Front Cell Neurosci 2020; 14:20. [PMID: 32116564 PMCID: PMC7026370 DOI: 10.3389/fncel.2020.00020] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are multifunctional, non-neuronal components of the central nervous system with diverse phenotypes that have gained much attention for their close involvement in neuroinflammation and neurodegenerative diseases. Glial phenotypes are primarily characterized by their structural and functional changes in response to various stimuli, which can be either neuroprotective or neurotoxic. The reliance of neurons on glial cells is essential to fulfill the energy demands of the brain for its proper functioning. Moreover, the glial cells perform distinct functions to regulate their own metabolic activities, as well as work in close conjunction with neurons through various secreted signaling or guidance molecules, thereby constituting a complex network of neuron-glial interactions in health and disease. The emerging evidence suggests that, in disease conditions, the metabolic alterations in the glial cells can induce structural and functional changes together with neuronal dysfunction indicating the importance of neuron-glia interactions in the pathophysiology of neurological disorders. This review covers the recent developments that implicate the regulation of glial phenotypic changes and its consequences on neuron-glia interactions in neurological disorders. Finally, we discuss the possibilities and challenges of targeting glial metabolism as a strategy to treat neurological disorders.
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Affiliation(s)
- Ruqayya Afridi
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Jong-Heon Kim
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Md Habibur Rahman
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Kyoungho Suk
- BK21 Plus KNU Biomedical Convergence Program, Department of Pharmacology, Brain Science and Engineering Institute, School of Medicine, Kyungpook National University, Daegu, South Korea
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55
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Wlodarek L, Cao F, Alibhai FJ, Fekete A, Noyan N, Tobin SW, Marvasti TB, Wu J, Li SH, Weisel RD, Wang LY, Jia Z, Li RK. Rectification of radiotherapy-induced cognitive impairments in aged mice by reconstituted Sca-1 + stem cells from young donors. J Neuroinflammation 2020; 17:51. [PMID: 32028989 PMCID: PMC7006105 DOI: 10.1186/s12974-019-1681-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/17/2019] [Indexed: 01/03/2023] Open
Abstract
Background Radiotherapy is widely used and effective for treating brain tumours, but inevitably impairs cognition as it arrests cellular processes important for learning and memory. This is particularly evident in the aged brain with limited regenerative capacity, where radiation produces irreparable neuronal damage and activation of neighbouring microglia. The latter is responsible for increased neuronal death and contributes to cognitive decline after treatment. To date, there are few effective means to prevent cognitive deficits after radiotherapy. Methods Here we implanted hematopoietic stem cells (HSCs) from young or old (2- or 18-month-old, respectively) donor mice expressing green fluorescent protein (GFP) into old recipients and assessed cognitive abilities 3 months post-reconstitution. Results Regardless of donor age, GFP+ cells homed to the brain of old recipients and expressed the macrophage/microglial marker, Iba1. However, only young cells attenuated deficits in novel object recognition and spatial memory and learning in old mice post-irradiation. Mechanistically, old recipients that received young HSCs, but not old, displayed significantly greater dendritic spine density and long-term potentiation (LTP) in CA1 neurons of the hippocampus. Lastly, we found that GFP+/Iba1+ cells from young and old donors were differentially polarized to an anti- and pro-inflammatory phenotype and produced neuroprotective factors and reactive nitrogen species in vivo, respectively. Conclusion Our results suggest aged peripherally derived microglia-like cells may exacerbate cognitive impairments after radiotherapy, whereas young microglia-like cells are polarized to a reparative phenotype in the irradiated brain, particularly in neural circuits associated with rewards, learning, and memory. These findings present a proof-of-principle for effectively reinstating central cognitive function of irradiated brains with peripheral stem cells from young donor bone marrow. Electronic supplementary material The online version of this article (10.1186/s12974-019-1681-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lukasz Wlodarek
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Feng Cao
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
| | - Faisal J Alibhai
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Adam Fekete
- Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
| | - Nima Noyan
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Stephanie W Tobin
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Tina B Marvasti
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Jun Wu
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Shu-Hong Li
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada
| | - Richard D Weisel
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada.,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Surgery, Division of Cardiac Surgery, University of Toronto, Toronto, ON, Canada
| | - Lu-Yang Wang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
| | - Zhengping Jia
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Program in Neurosciences & Mental Health, SickKids Research Institute, Floor 5, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
| | - Ren-Ke Li
- Toronto General Hospital Research Institute, University Health Network, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, M5G 1L7, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada. .,Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, ON, Canada. .,Department of Surgery, Division of Cardiac Surgery, University of Toronto, Toronto, ON, Canada.
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56
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Stratoulias V, Venero JL, Tremblay MÈ, Joseph B. Microglial subtypes: diversity within the microglial community. EMBO J 2019. [PMID: 31373067 DOI: 10.15252/embj.2019a101997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Microglia are brain-resident macrophages forming the first active immune barrier in the central nervous system. They fulfill multiple functions across development and adulthood and under disease conditions. Current understanding revolves around microglia acquiring distinct phenotypes upon exposure to extrinsic cues in their environment. However, emerging evidence suggests that microglia display differences in their functions that are not exclusively driven by their milieu, rather by the unique properties these cells possess. This microglial intrinsic heterogeneity has been largely overlooked, favoring the prevailing view that microglia are a single-cell type endowed with spectacular plasticity, allowing them to acquire multiple phenotypes and thereby fulfill their numerous functions in health and disease. Here, we review the evidence that microglia might form a community of cells in which each member (or "subtype") displays intrinsic properties and performs unique functions. Distinctive features and functional implications of several microglial subtypes are considered, across contexts of health and disease. Finally, we suggest that microglial subtype categorization shall be based on function and we propose ways for studying them. Hence, we advocate that plasticity (reaction states) and diversity (subtypes) should both be considered when studying the multitasking microglia.
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Affiliation(s)
- Vassilis Stratoulias
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jose Luis Venero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.,Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Marie-Ève Tremblay
- Department of Molecular Medicine, Université Laval, Quebec, QC, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada
| | - Bertrand Joseph
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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57
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Stratoulias V, Venero JL, Tremblay MÈ, Joseph B. Microglial subtypes: diversity within the microglial community. EMBO J 2019; 38:e101997. [PMID: 31373067 PMCID: PMC6717890 DOI: 10.15252/embj.2019101997] [Citation(s) in RCA: 313] [Impact Index Per Article: 62.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 12/03/2022] Open
Abstract
Microglia are brain‐resident macrophages forming the first active immune barrier in the central nervous system. They fulfill multiple functions across development and adulthood and under disease conditions. Current understanding revolves around microglia acquiring distinct phenotypes upon exposure to extrinsic cues in their environment. However, emerging evidence suggests that microglia display differences in their functions that are not exclusively driven by their milieu, rather by the unique properties these cells possess. This microglial intrinsic heterogeneity has been largely overlooked, favoring the prevailing view that microglia are a single‐cell type endowed with spectacular plasticity, allowing them to acquire multiple phenotypes and thereby fulfill their numerous functions in health and disease. Here, we review the evidence that microglia might form a community of cells in which each member (or “subtype”) displays intrinsic properties and performs unique functions. Distinctive features and functional implications of several microglial subtypes are considered, across contexts of health and disease. Finally, we suggest that microglial subtype categorization shall be based on function and we propose ways for studying them. Hence, we advocate that plasticity (reaction states) and diversity (subtypes) should both be considered when studying the multitasking microglia.
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Affiliation(s)
- Vassilis Stratoulias
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jose Luis Venero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.,Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Marie-Ève Tremblay
- Department of Molecular Medicine, Université Laval, Quebec, QC, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada
| | - Bertrand Joseph
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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58
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Guergues J, Zhang P, Liu B, Stevens SM. Improved Methodology for Sensitive and Rapid Quantitative Proteomic Analysis of Adult-Derived Mouse Microglia: Application to a Novel In Vitro Mouse Microglial Cell Model. Proteomics 2019; 19:e1800469. [PMID: 30980500 DOI: 10.1002/pmic.201800469] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/26/2019] [Indexed: 12/30/2022]
Abstract
Microglia, as the resident brain immune cells, can exhibit a broad range of activation phenotypes, which have been implicated in a multitude of central nervous system disorders. Current widely studied microglial cell lines are mainly derived from neonatal rodent brain that can limit their relevance to homeostatic function and disease-related neuroimmune responses in the adult brain. Recently, an adult mouse brain-derived microglial cell line has been established; however, a comprehensive proteome dataset remains lacking. Here, an optimization method for sensitive and rapid quantitative proteomic analysis of microglia is described that involves suspension trapping (S-Trap) for efficient and reproducible protein extraction from a limited number of microglial cells expected from an adult mouse brain (≈300 000). Using a 2-h gradient on a 75-cm UPLC column with a modified data dependent acquisition method on a hybrid quadrupole-Orbitrap mass spectrometer, 4855 total proteins have been identified where 4698 of which are quantifiable by label-free quantitation with a median and average coefficient of variation (CV) of 6.7% and 10.6%, respectively. This dataset highlights the high depth of proteome coverage and related quantitation precision of the adult-derived microglial proteome including proteins associated with several key pathways related to immune response. Data are available via ProteomeXchange with identifier PXD012006.
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Affiliation(s)
- Jennifer Guergues
- Department of Cell Biology, Microbiology, and Molecular Biology, Department of Biology, University of South Florida, Tampa, FL, 33620, USA.,Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT, 05446, USA
| | - Ping Zhang
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Bin Liu
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Stanley M Stevens
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT, 05446, USA
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59
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Gabandé‐Rodríguez E, Keane L, Capasso M. Microglial phagocytosis in aging and Alzheimer's disease. J Neurosci Res 2019; 98:284-298. [DOI: 10.1002/jnr.24419] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/20/2019] [Accepted: 03/08/2019] [Indexed: 01/24/2023]
Affiliation(s)
- Enrique Gabandé‐Rodríguez
- Department of Molecular Neuropathology Centro de Biología Molecular “Severo Ochoa” (CSIC‐UAM) Madrid Spain
| | - Lily Keane
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
| | - Melania Capasso
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
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60
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Aldana BI. Microglia-Specific Metabolic Changes in Neurodegeneration. J Mol Biol 2019; 431:1830-1842. [PMID: 30878483 DOI: 10.1016/j.jmb.2019.03.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/22/2019] [Accepted: 03/05/2019] [Indexed: 02/06/2023]
Abstract
The high energetic demand of the brain deems this organ rather sensitive to changes in energy supply. Therefore, even minor alterations in energy metabolism may underlie detrimental disturbances in brain function, contributing to the generation and progression of neurodegenerative diseases. Considerable evidence supports the key role of deficits in cerebral energy metabolism, particularly hypometabolism of glucose and mitochondrial dysfunction, in the pathophysiology of brain disorders. Major breakthroughs in the field of bioenergetics and neurodegeneration have been achieved through the use of in vitro and in vivo models of disease as well as sophisticated neuroimaging techniques in patients, yet these have been mainly focused on neuron and astrocyte function. Remarkably, the subcellular metabolic mechanisms linked to neurodegeneration that operate in other crucial brain cell types such as microglia have remain obscured, although they are beginning to be unraveled. Microglia, the brain-resident immune sentinels, perform a diverse range of functions that require a high-energy expenditure, namely, their role in brain development, maintenance of the neural environment, response to injury and infection, and activation of repair programs. Interestingly, another key mechanism underlying several neurodegenerative diseases is neuroinflammation, which can be associated with chronic microglia activation. Considering that many brain disorders are accompanied by changes in brain energy metabolism and sustained inflammation, and that energy metabolism has a strong influence on the inflammatory responses of microglia, the emerging significance of microglial energy metabolism in neurodegeneration is highlighted in this review.
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Affiliation(s)
- Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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61
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Milanova IV, Kalsbeek MJT, Wang XL, Korpel NL, Stenvers DJ, Wolff SEC, de Goede P, Heijboer AC, Fliers E, la Fleur SE, Kalsbeek A, Yi CX. Diet-Induced Obesity Disturbs Microglial Immunometabolism in a Time-of-Day Manner. Front Endocrinol (Lausanne) 2019; 10:424. [PMID: 31316470 PMCID: PMC6611391 DOI: 10.3389/fendo.2019.00424] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/12/2019] [Indexed: 12/16/2022] Open
Abstract
Background: Disturbance of immunometabolic signaling is a key process involved in the progression of obesity. Microglia-the resident immune cells in the brain, initiate local immune responses. It is known that hypercaloric diets lead to microglial activation. Previously, we observed that hypothalamic microglial cells from mice fed high-fat diet (HFD) lose their day/night rhythm and are constantly activated. However, little is known about daily rhythmicity in microglial circadian, immune and metabolic functions, either in lean or obese conditions. Therefore, we hypothesized that HFD disturbs microglial immunometabolism in a day/night-dependent manner. Methods: Obesity was induced in Wistar rats by feeding them HFD ad libitum for the duration of 8 weeks. Microglia were isolated from HFD- and chow-fed control animals at six time points during 24 h [every 4 h starting 2 h after lights on, i.e., Zeitgeber Time 2 (ZT2)]. Gene expression was evaluated using quantitative RT-PCR. JTK_Cycle software was used to estimate daily rhythmicity. Statistical analysis was performed with two-way ANOVA test. Results: Consumption of the obesogenic diet resulted in a 40 g significantly higher body weight gain in week 8, compared to chow diet (p < 0.0001), associated with increased adiposity. We observed significant rhythmicity of circadian clock genes in microglia under chow conditions, which was partially lost in diet-induced obesity (DIO). Microglial immune gene expression also showed time-of-day differences, which were disrupted in HFD-fed animals. Microglia responded to the obesogenic conditions by a shift of substrate utilization with decreased glutamate and glucose metabolism in the active period of the animals, and an overall increase of lipid metabolism, as indicated by gene expression evaluation. Additionally, data on mitochondria bioenergetics and dynamics suggested an increased energy production in microglia during the inactive period on HFD. Finally, evaluation of monocyte functional gene expression showed small or absent effect of HFD on peripheral myeloid cells, suggesting a cell-specific microglial inflammatory response in DIO. Conclusions: An obesogenic diet affects microglial immunometabolism in a time-of-day dependent manner. Given the central role of the brain in energy metabolism, a better knowledge of daily rhythms in microglial immunometabolism could lead to a better understanding of the pathogenesis of obesity.
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Affiliation(s)
- Irina V. Milanova
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Martin J. T. Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Xiao-Lan Wang
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Nikita L. Korpel
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Dirk Jan Stenvers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Samantha E. C. Wolff
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Paul de Goede
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Annemieke C. Heijboer
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Susanne E. la Fleur
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- *Correspondence: Chun-Xia Yi
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Abstract
A century ago, Pío del Río-Hortega discovered that microglial cells are endowed with remarkable dynamic and plastic capabilities. The real-time plasticity of microglia could be revealed, however, only during the last 15 years with the development of new transgenic animal models and new molecular and functional analysis methods. Phenotyping microglia in situ with these new tools sealed the fate of the classical two state model of "resting" microglia in physiological conditions and "activated" microglia in pathological conditions. Our current view on functional behavior of microglia takes into account the exquisite reactivity of these immune cells to changes occurring in the CNS in both physiological and pathological conditions. We briefly review here the results and methods that have uncovered the dynamics and versatility of microglial reactivity.
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63
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Angelova DM, Brown DR. Altered Processing of β-Amyloid in SH-SY5Y Cells Induced by Model Senescent Microglia. ACS Chem Neurosci 2018; 9:3137-3152. [PMID: 30052418 DOI: 10.1021/acschemneuro.8b00334] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The single greatest risk factor for neurodegenerative diseases is aging. Aging of cells such as microglia in the nervous system has an impact not only on the ability of those cells to function but also on cells they interact with. We have developed a model microglia system that recapitulates the dystrophic/senescent phenotype, and we have combined this with the study of β-amyloid processing. The model is based on the observation that aged microglia have increased iron content. By overloading a human microglial cell line with iron, we were able to change the secretory profile of the microglia. When combining these senescent microglia with SH-SY5Y cells, we noted an increase in extracellular β-amyloid. The increased levels of β-amyloid were due to a decrease in the release of insulin-degrading enzyme by the model senescent microglia. Further analysis revealed that the senescent microglia showed both decreased autophagy and increased ER stress. These studies demonstrate the potential impact of an aging microglial population in terms of β-amyloid produced by neurons, which could play a causal role in diseases like Alzheimer's disease. Our results also further develop the potential utility of an in vitro model of senescent microglia for the study of brain aging and neurodegenerative disease.
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Affiliation(s)
- Dafina M. Angelova
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, U.K
| | - David R. Brown
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, U.K
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64
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Borst K, Schwabenland M, Prinz M. Microglia metabolism in health and disease. Neurochem Int 2018; 130:104331. [PMID: 30423423 DOI: 10.1016/j.neuint.2018.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/24/2018] [Accepted: 11/08/2018] [Indexed: 12/11/2022]
Abstract
In the last decade tremendous progress has been made in understanding how the immune system reacts to insults. During this progress it became obvious that those immune responses are tightly regulated and cross-linked with distinct metabolic changes in immune cells. Extensive research has been conducted mainly on subtypes of T cells, which use different metabolic pathways during differentiation processes and activation states. In addition, it has also been established later, that the innate immune cell lineage of myeloid cells includes a variety of different subsets of bone marrow-derived as well as tissue-specific macrophages, which elicit much more functions than simply killing bacteria. To execute this high variety of functions, also macrophages use different metabolic pathways and are tightly regulated by key metabolic regulators, such as the mechanistic target of rapamycin (mTOR). Upon activation, metabolic changes within the cell occur to meet the requirements of the phenotypic switch. In addition, metabolic changes correlate with the ability of innate immune cells to show hallmarks of adaptive immune responses. Little is known about specific metabolic changes of myeloid cells and specifically microglia in vivo. Microglia are key players in neurodegenerative and neuroinflammatory diseases and have become a major target of medical research. Here, we review the existing data on microglia metabolism and the connection of microglia phenotypes with neuroinflammatory and neurodegenerative diseases. Lastly, we will discuss how our knowledge about the cellular metabolism might be used to develop new treatment options for neurological diseases.
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Affiliation(s)
- Katharina Borst
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Germany
| | - Marius Schwabenland
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany.
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65
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Alibhai JD, Diack AB, Manson JC. Unravelling the glial response in the pathogenesis of Alzheimer's disease. FASEB J 2018; 32:5766-5777. [PMID: 30376380 DOI: 10.1096/fj.201801360r] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease is a progressive, incurable neurodegenerative disease targeting specific neuronal populations within the brain while neighboring neurons appear unaffected. The focus for defining mechanisms has therefore been on the pathogenesis in affected neuronal populations and developing intervention strategies to prevent their cell death. However, there is growing recognition of the importance of glial cells in the development of pathology. Determining exactly how glial cells are involved in the disease process and the susceptibility of the aging brain provides unprecedented challenges. The present review examines recent studies attempting to unravel the glial response during the course of disease and how this action may dictate the outcome of neurodegeneration. The importance of regional heterogeneity of glial cells within the CNS during healthy aging and disease is examined to understand how the glial cells may contribute to neuronal susceptibility or resilience during the neurodegenerative process.-Alibhai, J. D., Diack, A. B., Manson, J. C. Unravelling the glial response in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- James D Alibhai
- National Creutzfeldt-Jakob Disease (CJD) Research and Surveillance Unit, University of Edinburgh, Edinburgh, United Kingdom.,UK Dementia Research Institute, University of Edinburgh, Edinburgh, United Kingdom; and
| | - Abigail B Diack
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
| | - Jean C Manson
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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66
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Silvin A, Ginhoux F. Microglia heterogeneity along a spatio-temporal axis: More questions than answers. Glia 2018; 66:2045-2057. [PMID: 30144321 DOI: 10.1002/glia.23458] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/05/2018] [Accepted: 05/04/2018] [Indexed: 12/29/2022]
Abstract
Microglia are resident macrophages of the central nervous system; they arise during early embryonic development and persist throughout adulthood. These unique cells provide developmental support, contribute to adult brain homeostasis and impart immune protection during infection. Dysregulated microglia are implicated in the pathophysiology of several neurological disorders, including Alzheimer disease, and as such, a better understanding of their regulation and function is required for rational therapeutic design. Recent studies have highlighted the various heterogeneous aspects of microglia, such as their wide differentiation spectrum from early embryogenesis to adulthood, their location in different brain regions and their responses to ageing, infection and inflammation. In this review, we discuss microglial heterogeneity in time and space and highlight the remaining questions arising from such heterogeneity.
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Affiliation(s)
- Aymeric Silvin
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, IMMUNOS Building #3-4, BIOPOLIS, 138648, Singapore
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, IMMUNOS Building #3-4, BIOPOLIS, 138648, Singapore.,Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
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67
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Model Senescent Microglia Induce Disease Related Changes in α-Synuclein Expression and Activity. Biomolecules 2018; 8:biom8030067. [PMID: 30071596 PMCID: PMC6164966 DOI: 10.3390/biom8030067] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022] Open
Abstract
Aging is the most prominent risk factor for most neurodegenerative diseases. However, incorporating aging-related changes into models of neurodegeneration rarely occurs. One of the significant changes that occurs in the brain as we age is the shift in phenotype of the resident microglia population to one less able to respond to deleterious changes in the brain. These microglia are termed dystrophic microglia. In order to better model neurodegenerative diseases, we have developed a method to convert microglia into a senescent phenotype in vitro. Mouse microglia grown in high iron concentrations showed many characteristics of dystrophic microglia including, increased iron storage, increased expression of proteins, such as ferritin and the potassium channel, Kv1.3, increased reactive oxygen species production and cytokine release. We have applied this new model to the study of α-synuclein, a protein that is closely associated with a number of neurodegenerative diseases. We have shown that conditioned medium from our model dystrophic microglia increases α-synuclein transcription and expression via tumor necrosis factor alpha (TNFα) and mediated through nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The conditioned medium also decreases the formation of α-synuclein tetramers, associated ferrireductase activity, and increases aggregates of α-synuclein. The results suggest that we have developed an interesting new model of aged microglia and that factors, including TNFα released from dystrophic microglia could have a significant influence on the pathogenesis of α-synuclein related diseases.
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68
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Nadjar A. Role of metabolic programming in the modulation of microglia phagocytosis by lipids. Prostaglandins Leukot Essent Fatty Acids 2018; 135:63-73. [PMID: 30103935 DOI: 10.1016/j.plefa.2018.07.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 07/11/2018] [Accepted: 07/11/2018] [Indexed: 02/06/2023]
Abstract
Microglia phagocytosis is an essential process to maintain lifelong brain homeostasis and clear potential toxic factors from the neuropil. Microglia can engulf cells or part of cells through the expression of specific receptors at their surface and activation of downstream signaling pathways to engulf material. Microglia phagocytosis is finely regulated and is under the dependence of many factors, including environmental cues such as dietary lipids. Yet, the molecular mechanisms implicated are still largely unknown. The present publication is a 'hypothesis review', assessing the possibility that lipid-mediated modulation of phagocytosis occurs by affecting bioenergetic pathways within microglia. I assess our present knowledge and the elements that allow drawing such hypothesis. I also list some of the important gaps in the literature that need to be filled in. I also consider opportunities for future therapeutic target including nutritional interventions.
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Affiliation(s)
- A Nadjar
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux 33076, France; University Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux 33076, France.
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69
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Rangaraju S, Dammer EB, Raza SA, Gao T, Xiao H, Betarbet R, Duong DM, Webster JA, Hales CM, Lah JJ, Levey AI, Seyfried NT. Quantitative proteomics of acutely-isolated mouse microglia identifies novel immune Alzheimer's disease-related proteins. Mol Neurodegener 2018; 13:34. [PMID: 29954413 PMCID: PMC6025801 DOI: 10.1186/s13024-018-0266-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/18/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are innate immune cells of the brain that perform phagocytic and inflammatory functions in disease conditions. Transcriptomic studies of acutely-isolated microglia have provided novel insights into their molecular and functional diversity in homeostatic and neurodegenerative disease states. State-of-the-art mass spectrometry methods can comprehensively characterize proteomic alterations in microglia in neurodegenerative disorders, potentially providing novel functionally relevant molecular insights that are not provided by transcriptomics. However, comprehensive proteomic profiling of adult primary microglia in neurodegenerative disease conditions has not been performed. METHODS We performed quantitative mass spectrometry based proteomic analyses of purified CD11b+ acutely-isolated microglia from adult (6 mo) mice in normal, acute neuroinflammatory (LPS-treatment) and chronic neurodegenerative states (5xFAD model of Alzheimer's disease [AD]). Differential expression analyses were performed to characterize specific microglial proteomic changes in 5xFAD mice and identify overlap with LPS-induced pro-inflammatory changes. Our results were also contrasted with existing proteomic data from wild-type mouse microglia and from existing microglial transcriptomic data from wild-type and 5xFAD mice. Neuropathological validation studies of select proteins were performed in human AD and 5xFAD brains. RESULTS Of 4133 proteins identified, 187 microglial proteins were differentially expressed in the 5xFAD mouse model of AD pathology, including proteins with previously known (Apoe, Clu and Htra1) as well as previously unreported relevance to AD biology (Cotl1 and Hexb). Proteins upregulated in 5xFAD microglia shared significant overlap with pro-inflammatory changes observed in LPS-treated mice. Several proteins increased in human AD brain were also upregulated by 5xFAD microglia (Aβ peptide, Apoe, Htra1, Cotl1 and Clu). Cotl1 was identified as a novel microglia-specific marker with increased expression and strong association with AD neuropathology. Apoe protein was also detected within plaque-associated microglia in which Apoe and Aβ were highly co-localized, suggesting a role for Apoe in phagocytic clearance of Aβ. CONCLUSIONS We report a comprehensive proteomic study of adult mouse microglia derived from acute neuroinflammation and AD models, representing a valuable resource to the neuroscience research community. We highlight shared and unique microglial proteomic changes in acute neuroinflammation aging and AD mouse models and identify novel roles for microglial proteins in human neurodegeneration.
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Affiliation(s)
| | - Eric B Dammer
- Department of Biochemistry, Emory University, Atlanta, GA, 30322, USA
| | - Syed Ali Raza
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Tianwen Gao
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Hailian Xiao
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Ranjita Betarbet
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Duc M Duong
- Department of Biochemistry, Emory University, Atlanta, GA, 30322, USA
| | - James A Webster
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Chadwick M Hales
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - James J Lah
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Allan I Levey
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Nicholas T Seyfried
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA. .,Department of Biochemistry, Emory University, Atlanta, GA, 30322, USA.
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70
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Nagy AM, Fekete R, Horvath G, Koncsos G, Kriston C, Sebestyen A, Giricz Z, Kornyei Z, Madarasz E, Tretter L. Versatility of microglial bioenergetic machinery under starving conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1859:201-214. [PMID: 29273412 DOI: 10.1016/j.bbabio.2017.12.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/11/2017] [Accepted: 12/16/2017] [Indexed: 11/18/2022]
Abstract
Microglia are highly dynamic cells in the brain. Their functional diversity and phenotypic versatility brought microglial energy metabolism into the focus of research. Although it is known that microenvironmental cues shape microglial phenotype, their bioenergetic response to local nutrient availability remains unclear. In the present study effects of energy substrates on the oxidative and glycolytic metabolism of primary - and BV-2 microglial cells were investigated. Cellular oxygen consumption, glycolytic activity, the levels of intracellular ATP/ADP, autophagy, mTOR phosphorylation, apoptosis and cell viability were measured in the absence of nutrients or in the presence of physiological energy substrates: glutamine, glucose, lactate, pyruvate or ketone bodies. All of the oxidative energy metabolites increased the rate of basal and maximal respiration. However, the addition of glucose decreased microglial oxidative metabolism and glycolytic activity was enhanced. Increased ATP/ADP ratio and cell viability, activation of the mTOR and reduction of autophagic activity were observed in glutamine-supplemented media. Moreover, moderate and transient oxidation of ketone bodies was highly enhanced by glutamine, suggesting that anaplerosis of the TCA-cycle could stimulate ketone body oxidation. It is concluded that microglia show high metabolic plasticity and utilize a wide range of substrates. Among them glutamine is the most efficient metabolite. To our knowledge these data provide the first account of microglial direct metabolic response to nutrients under short-term starvation and demonstrate that microglia exhibit versatile metabolic machinery. Our finding that microglia have a distinct bioenergetic profile provides a critical foundation for specifying microglial contributions to brain energy metabolism.
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Affiliation(s)
- Adam M Nagy
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 1094 Tuzolto st. 37-47, Budapest, Hungary
| | - Rebeka Fekete
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Szigony st. 43, Budapest, Hungary
| | - Gergo Horvath
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 1094 Tuzolto st. 37-47, Budapest, Hungary
| | - Gabor Koncsos
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Nagyvarad square 4, Budapest, Hungary
| | - Csilla Kriston
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, 1085 Ulloi st. 26, Budapest, Hungary
| | - Anna Sebestyen
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, 1085 Ulloi st. 26, Budapest, Hungary
| | - Zoltan Giricz
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Nagyvarad square 4, Budapest, Hungary
| | - Zsuzsanna Kornyei
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Szigony st. 43, Budapest, Hungary
| | - Emilia Madarasz
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Szigony st. 43, Budapest, Hungary
| | - Laszlo Tretter
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 1094 Tuzolto st. 37-47, Budapest, Hungary.
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71
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Mangold CA, Wronowski B, Du M, Masser DR, Hadad N, Bixler GV, Brucklacher RM, Ford MM, Sonntag WE, Freeman WM. Sexually divergent induction of microglial-associated neuroinflammation with hippocampal aging. J Neuroinflammation 2017; 14:141. [PMID: 28732515 PMCID: PMC5521082 DOI: 10.1186/s12974-017-0920-8] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 07/13/2017] [Indexed: 01/11/2023] Open
Abstract
Background The necessity of including both males and females in molecular neuroscience research is now well understood. However, there is relatively limited basic biological data on brain sex differences across the lifespan despite the differences in age-related neurological dysfunction and disease between males and females. Methods Whole genome gene expression of young (3 months), adult (12 months), and old (24 months) male and female C57BL6 mice hippocampus was analyzed. Subsequent bioinformatic analyses and confirmations of age-related changes and sex differences in hippocampal gene and protein expression were performed. Results Males and females demonstrate both common expression changes with aging and marked sex differences in the nature and magnitude of the aging responses. Age-related hippocampal induction of neuroinflammatory gene expression was sexually divergent and enriched for microglia-specific genes such as complement pathway components. Sexually divergent C1q protein expression was confirmed by immunoblotting and immunohistochemistry. Similar patterns of cortical sexually divergent gene expression were also evident. Additionally, inter-animal gene expression variability increased with aging in males, but not females. Conclusions These findings demonstrate sexually divergent neuroinflammation with aging that may contribute to sex differences in age-related neurological diseases such as stroke and Alzheimer’s, specifically in the complement system. The increased expression variability in males suggests a loss of fidelity in gene expression regulation with aging. These findings reveal a central role of sex in the transcriptomic response of the hippocampus to aging that warrants further, in depth, investigations. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0920-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Colleen A Mangold
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, PA, USA
| | - Benjamin Wronowski
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mei Du
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Dustin R Masser
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Niran Hadad
- Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Georgina V Bixler
- Genome Sciences Facility, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Robert M Brucklacher
- Genome Sciences Facility, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Matthew M Ford
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - William E Sonntag
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, USA
| | - Willard M Freeman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Reynolds Oklahoma Center on Aging & Nathan Shock Center of Excellence in the Biology of Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, USA. .,, SLY-BRC 1370, 975 NE 10th St, Oklahoma City, OK, 73104, USA.
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