1
|
You Y, An DD, Wan YS, Zheng BX, Dai HB, Zhang SH, Zhang XN, Wang RR, Shi P, Jin M, Wang Y, Jiang L, Chen Z, Hu WW. Cell-specific IL-1R1 regulates the regional heterogeneity of microglial displacement of GABAergic synapses and motor learning ability. Cell Mol Life Sci 2024; 81:116. [PMID: 38438808 PMCID: PMC10912170 DOI: 10.1007/s00018-023-05111-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 03/06/2024]
Abstract
Microglia regulate synaptic function in various ways, including the microglial displacement of the surrounding GABAergic synapses, which provides important neuroprotection from certain diseases. However, the physiological role and underlying mechanisms of microglial synaptic displacement remain unclear. In this study, we observed that microglia exhibited heterogeneity during the displacement of GABAergic synapses surrounding neuronal soma in different cortical regions under physiological conditions. Through three-dimensional reconstruction, in vitro co-culture, two-photon calcium imaging, and local field potentials recording, we found that IL-1β negatively modulated microglial synaptic displacement to coordinate regional heterogeneity in the motor cortex, which impacted the homeostasis of the neural network and improved motor learning ability. We used the Cre-Loxp system and found that IL-1R1 on glutamatergic neurons, rather than that on microglia or GABAergic neurons, mediated the negative effect of IL-1β on synaptic displacement. This study demonstrates that IL-1β is critical for the regional heterogeneity of synaptic displacement by coordinating different actions of neurons and microglia via IL-1R1, which impacts both neural network homeostasis and motor learning ability. It provides a theoretical basis for elucidating the physiological role and mechanism of microglial displacement of GABAergic synapses.
Collapse
Affiliation(s)
- Yi You
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Da-Dao An
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yu-Shan Wan
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Bai-Xiu Zheng
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Hai-Bin Dai
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - She-Hong Zhang
- Department of Rehabilitation Medicine, Huzhou Central Hospital, Affiliated Huzhou Hospital, Zhejiang University School of Medicine, Huzhou, 313000, China
| | - Xiang-Nan Zhang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Rong-Rong Wang
- Department of Clinical Pharmacy, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Peng Shi
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Mingjuan Jin
- Department of Epidemiology and Biostatistics, Zhejiang University School of Public Health, Hangzhou, 310058, China
| | - Yi Wang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Lei Jiang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Wei-Wei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| |
Collapse
|
2
|
Dadwal S, Heneka MT. Microglia heterogeneity in health and disease. FEBS Open Bio 2024; 14:217-229. [PMID: 37945346 PMCID: PMC10839410 DOI: 10.1002/2211-5463.13735] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/12/2023] [Accepted: 11/08/2023] [Indexed: 11/12/2023] Open
Abstract
Microglia, the resident immune cells of the central nervous system (CNS), have received significant attention due to their critical roles in maintaining brain homeostasis and mediating cerebral immune responses. Understanding the origin of microglia has been a subject of great interest, and emerging evidence suggests that microglia consist of multiple subpopulations with unique molecular and functional characteristics. These subpopulations of microglia may exhibit specialized roles in response to different environmental cues as in disease conditions. The newfound understanding of microglial heterogeneity has significant implications for elucidating their roles in both physiological and pathological conditions. In the context of disease, microglia have been studied rigorously as they play a very important role in neuroinflammation. Dysregulated microglial activation and function contribute to chronic inflammation. Further exploration of microglial heterogeneity and their interactions with other cell types in the CNS will undoubtedly pave the way to novel therapeutic strategies targeting microglia-mediated pathologies. In this review, we discuss the latest advances in the field of microglia research, focusing specifically on the origin and subpopulations of microglia, the populations of microglia types in the brains of patients with neurodegenerative diseases, and how microglia are regulated in the healthy CNS.
Collapse
Affiliation(s)
- Shilauni Dadwal
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
| | - Michael T. Heneka
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
- Division of Infectious Diseases and ImmunologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
| |
Collapse
|
3
|
González Ibáñez F, Halvorson T, Sharma K, McKee CG, Carrier M, Picard K, Vernoux N, Bisht K, Deslauriers J, Lalowski M, Tremblay MÈ. Ketogenic diet changes microglial morphology and the hippocampal lipidomic profile differently in stress susceptible versus resistant male mice upon repeated social defeat. Brain Behav Immun 2023; 114:383-406. [PMID: 37689276 DOI: 10.1016/j.bbi.2023.09.006] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/30/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023] Open
Abstract
Psychological stress confers an increased risk for several diseases including psychiatric conditions. The susceptibility to psychological stress is modulated by various factors, many of them being modifiable lifestyle choices. The ketogenic diet (KD) has emerged as a dietary regime that offers positive outcomes on mood and health status. Psychological stress and elevated inflammation are common features of neuropsychiatric disorders such as certain types of major depressive disorder. KD has been attributed anti-inflammatory properties that could underlie its beneficial consequences on the brain and behavior. Microglia are the main drivers of inflammation in the central nervous system. They are known to respond to both dietary changes and psychological stress, notably by modifying their production of cytokines and relationships among the brain parenchyma. To assess the interactions between KD and the stress response, including effects on microglia, we examined adult male mice on control diet (CD) versus KD that underwent 10 days of repeated social defeat (RSD) or remained non-stressed (controls; CTRLs). Through a social interaction test, stressed mice were classified as susceptible (SUS) or resistant (RES) to RSD. The mouse population fed a KD tended to have a higher proportion of individuals classified as RES following RSD. Microglial morphology and ultrastructure were then analyzed in the ventral hippocampus CA1, a brain region known to present structural alterations as a response to psychological stress. Distinct changes in microglial soma and arborization linked to the KD, SUS and RES phenotypes were revealed. Ultrastructural analysis by electron microscopy showed a clear reduction of cellular stress markers in microglia from KD fed animals. Furthermore, ultrastructural analysis showed that microglial contacts with synaptic elements were reduced in the SUS compared to the RES and CTRL groups. Hippocampal lipidomic analyses lastly identified a distinct lipid profile in SUS animals compared to CTRLs. These key differences, combined with the distinct microglial responses to diet and stress, indicate that unique metabolic changes may underlie the stress susceptibility phenotypes. Altogether, our results reveal novel mechanisms by which a KD might improve the resistance to psychological stress.
Collapse
Affiliation(s)
- Fernando González Ibáñez
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Torin Halvorson
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada; Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kaushik Sharma
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Department of Chemistry, Purdue University, West Lafayette, Indiana, United States
| | - Chloe Grace McKee
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Micaël Carrier
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Katherine Picard
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Nathalie Vernoux
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
| | - Kanchan Bisht
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Department of Chemistry, Purdue University, West Lafayette, Indiana, United States
| | | | - Maciej Lalowski
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland; Biochemistry/Developmental Biology and HiLIFE, Meilahti Clinical Proteomics Core Facility, University of Helsinki, Finland
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada; Département de Médecine Moléculaire, Université Laval, Québec, Quebec, Canada; Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada; Neurology and Neurosurgery Department, McGill University, Montréal, Quebec, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada; Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, British Columbia, Canada.
| |
Collapse
|
4
|
González Ibáñez F, Halvorson T, Sharma K, McKee C, Carrier M, Picard K, Vernoux N, Bisht K, Deslauriers J, Lalowski M, Tremblay MÈ. Ketogenic diet alters microglial morphology and changes the hippocampal lipidomic profile distinctively in stress susceptible versus resistant male mice upon repeated social defeat. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555135. [PMID: 37693370 PMCID: PMC10491121 DOI: 10.1101/2023.08.28.555135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Psychological stress confers an increased risk for several diseases including psychiatric conditions. The susceptibility to psychological stress is modulated by various factors, many of them being modifiable lifestyle choices. The ketogenic diet (KD) has emerged as a dietary regime that offers positive outcomes on mood and health status. Psychological stress and elevated inflammation are common features of neuropsychiatric disorders such as certain types of major depressive disorder. KD has been attributed anti-inflammatory properties that could underlie its beneficial consequences on the brain and behavior. Microglia are the main drivers of inflammation in the central nervous system. They are known to respond to both dietary changes and psychological stress, notably by modifying their production of cytokines and relationships among the brain parenchyma. To assess the interactions between KD and the stress response, including effects on microglia, we examined adult male mice on control diet (CD) versus KD that underwent 10 days of repeated social defeat (RSD) or remained non-stressed (controls; CTRLs). Through a social interaction test, stressed mice were classified as susceptible (SUS) or resistant (RES) to RSD. The mouse population fed a KD tended to have a higher proportion of individuals classified as RES following RSD. Microglial morphology and ultrastructure were then analyzed in the ventral hippocampus CA1, a brain region known to present structural alterations as a response to psychological stress. Distinct changes in microglial soma and arborization linked to the KD, SUS and RES phenotypes were revealed. Ultrastructural analysis by electron microscopy showed a clear reduction of cellular stress markers in microglia from KD fed animals. Furthermore, ultrastructural analysis showed that microglial contacts with synaptic elements were reduced in the SUS compared to the RES and CTRL groups. Hippocampal lipidomic analyses lastly identified a distinct lipid profile in SUS animals compared to CTRLs. These key differences, combined with the distinct microglial responses to diet and stress, indicate that unique metabolic changes may underlie the stress susceptibility phenotypes. Altogether, our results reveal novel mechanisms by which a KD might improve the resistance to psychological stress.
Collapse
Affiliation(s)
- Fernando González Ibáñez
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Torin Halvorson
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kaushik Sharma
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Department of Chemistry, Purdue University, West Lafayette, IN, United States of America
| | - Chloe McKee
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Micaël Carrier
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Katherine Picard
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Nathalie Vernoux
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Kanchan Bisht
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Department of Chemistry, Purdue University, West Lafayette, IN, United States of America
| | | | - Maciej Lalowski
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
- Biochemistry/Developmental Biology, Meilahti Clinical Proteomics Core Facility, University of Helsinki, Finland
| | - Marie-Ève Tremblay
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, BC, Canada
| |
Collapse
|
5
|
Wang J, He W, Zhang J. A richer and more diverse future for microglia phenotypes. Heliyon 2023; 9:e14713. [PMID: 37025898 PMCID: PMC10070543 DOI: 10.1016/j.heliyon.2023.e14713] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/01/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023] Open
Abstract
Microglia are the only resident innate immune cells derived from the mesoderm in the nerve tissue. They play a role in the development and maturation of the central nervous system (CNS). Microglia mediate the repair of CNS injury and participate in endogenous immune response induced by various diseases by exerting neuroprotective or neurotoxic effects. Traditionally, microglia are considered to be in a resting state, the M0 type, under physiological conditions. In this state, they perform immune surveillance by constantly monitoring pathological responses in the CNS. In the pathological state, microglia undergo a series of morphological and functional changes from the M0 state and eventually polarize into classically activated microglia (M1) and alternatively activated microglia (M2). M1 microglia release inflammatory factors and toxic substances to inhibit pathogens, while M2 microglia exert neuroprotective effects by promoting nerve repair and regeneration. However, in recent years, the view regarding M1/M2 polarization of microglia has gradually changed. According to some researchers, the phenomenon of microglia polarization is not yet confirmed. The M1/M2 polarization term is used for a simplified description of its phenotype and function. Other researchers believe that the microglia polarization process is rich and diverse, and consequently, the classification method of M1/M2 has limitations. This conflict hinders the academic community from establishing more meaningful microglia polarization pathways and terms, and therefore, a careful revision of the concept of microglia polarization is required. The present article briefly reviews the current consensus and controversy regarding microglial polarization typing to provide supporting materials for a more objective understanding of the functional phenotype of microglia.
Collapse
|
6
|
Bakina O, Kettenmann H, Nolte C. Microglia form satellites with different neuronal subtypes in the adult murine central nervous system. J Neurosci Res 2022; 100:1105-1122. [PMID: 35213755 DOI: 10.1002/jnr.25026] [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: 04/23/2021] [Revised: 12/21/2021] [Accepted: 01/07/2022] [Indexed: 11/12/2022]
Abstract
Microglia are the innate immune cells of the central nervous system (CNS). In the adult uncompromised CNS, they have a highly ramified morphology and continuously extend and retract their processes. A subpopulation of microglial cells forms close soma-to-soma contacts with neurons and have been termed satellite microglia, yet the role of such interaction is largely unknown. Here, we analyzed the distribution of satellite microglia in different areas of the CNS of adult male mice applying transgenic- and immunolabeling of neuronal subtypes and microglia followed by three-dimensional imaging analysis. We quantified satellite microglia associated with GABAergic and glutamatergic neurons in the somatosensory cortex, striatum, and thalamus; with dopaminergic and serotonergic neurons in the basal forebrain and raphe nucleus, respectively; and with cerebellar Purkinje cell neurons. Satellite microglia in the retina were assessed qualitatively. Microglia form satellites with all neuronal subtypes studied, whereas a preference for a specific neuron subtype was not found. The occurrence and frequency of satellite microglia is determined by the histo-architectural organization of the brain area and the densities of neuronal somata therein.
Collapse
Affiliation(s)
- Olga Bakina
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Helmut Kettenmann
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Christiane Nolte
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| |
Collapse
|
7
|
Matisz C, Gruber A. Neuroinflammatory remodeling of the anterior cingulate cortex as a key driver of mood disorders in gastrointestinal disease and disorders. Neurosci Biobehav Rev 2022; 133:104497. [DOI: 10.1016/j.neubiorev.2021.12.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 11/10/2021] [Accepted: 12/09/2021] [Indexed: 02/08/2023]
|
8
|
Carrier M, Šimončičová E, St-Pierre MK, McKee C, Tremblay MÈ. Psychological Stress as a Risk Factor for Accelerated Cellular Aging and Cognitive Decline: The Involvement of Microglia-Neuron Crosstalk. Front Mol Neurosci 2021; 14:749737. [PMID: 34803607 PMCID: PMC8599581 DOI: 10.3389/fnmol.2021.749737] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/16/2021] [Indexed: 12/22/2022] Open
Abstract
The relationship between the central nervous system (CNS) and microglia is lifelong. Microglia originate in the embryonic yolk sac during development and populate the CNS before the blood-brain barrier forms. In the CNS, they constitute a self-renewing population. Although they represent up to 10% of all brain cells, we are only beginning to understand how much brain homeostasis relies on their physiological functions. Often compared to a double-edged sword, microglia hold the potential to exert neuroprotective roles that can also exacerbate neurodegeneration once compromised. Microglia can promote synaptic growth in addition to eliminating synapses that are less active. Synaptic loss, which is considered one of the best pathological correlates of cognitive decline, is a distinctive feature of major depressive disorder (MDD) and cognitive aging. Long-term psychological stress accelerates cellular aging and predisposes to various diseases, including MDD, and cognitive decline. Among the underlying mechanisms, stress-induced neuroinflammation alters microglial interactions with the surrounding parenchymal cells and exacerbates oxidative burden and cellular damage, hence inducing changes in microglia and neurons typical of cognitive aging. Focusing on microglial interactions with neurons and their synapses, this review discusses the disrupted communication between these cells, notably involving fractalkine signaling and the triggering receptor expressed on myeloid cells (TREM). Overall, chronic stress emerges as a key player in cellular aging by altering the microglial sensome, notably via fractalkine signaling deficiency. To study cellular aging, novel positron emission tomography radiotracers for TREM and the purinergic family of receptors show interest for human study.
Collapse
Affiliation(s)
- Micaël Carrier
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Eva Šimončičová
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Marie-Kim St-Pierre
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
| | - Chloe McKee
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Department of Molecular Medicine, Université Laval, Québec City, QC, Canada.,Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
9
|
Krukowski K, Nolan A, Becker M, Picard K, Vernoux N, Frias ES, Feng X, Tremblay ME, Rosi S. Novel microglia-mediated mechanisms underlying synaptic loss and cognitive impairment after traumatic brain injury. Brain Behav Immun 2021; 98:122-135. [PMID: 34403733 PMCID: PMC9119574 DOI: 10.1016/j.bbi.2021.08.210] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 12/30/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of long-term neurological disability in the world. Currently, there are no therapeutics for treating the deleterious consequences of brain trauma; this is in part due to a lack of complete understanding of cellular processes that underlie TBI-related pathologies. Following TBI, microglia, the brain resident immune cells, turn into a "reactive" state characterized by the production of inflammatory mediators that contribute to the development of cognitive deficits. Utilizing multimodal, state-of-the-art techniques that widely span from ultrastructural analysis to optogenetic interrogation of circuit function, we investigated the reactive microglia phenotype one week after injury when learning and memory deficits are also measured. Microglia displayed increased: (i) phagocytic activity in vivo, (ii) synaptic engulfment, (iii) increased neuronal contact, including with dendrites and somata (termed 'satellite microglia'). Functionally, satellite microglia might impact somatic inhibition as demonstrated by the associated reduction in inhibitory synaptic drive. Cumulatively, here we demonstrate novel microglia-mediated mechanisms that may contribute to synaptic loss and cognitive impairment after traumatic brain injury.
Collapse
Affiliation(s)
- Karen Krukowski
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA, Brain and Spinal Injury Center, University of California, San Francisco, CA, USA
| | - Amber Nolan
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA, Brain and Spinal Injury Center, University of California, San Francisco, CA, USA
| | - McKenna Becker
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA, Brain and Spinal Injury Center, University of California, San Francisco, CA, USA
| | - Katherine Picard
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Nathalie Vernoux
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Elma S. Frias
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA, Brain and Spinal Injury Center, University of California, San Francisco, CA, USA, Department of Biomedical Sciences, University of California, San Francisco, CA, USA
| | - Xi Feng
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA, Brain and Spinal Injury Center, University of California, San Francisco, CA, USA
| | - Marie-Eve Tremblay
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada; Molecular Medicine Department, Université Laval, Québec, QC, Canada; Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada.
| | - Susanna Rosi
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA; Brain and Spinal Injury Center, University of California, San Francisco, CA, USA; Department of Biomedical Sciences, University of California, San Francisco, CA, USA; Department of Neurological Surgery, University of California, San Francisco, CA, USA; Weill Institute for Neuroscience, University of California San Francisco, CA, USA; Kavli Institute of Fundamental Neuroscience, University of California San Francisco, CA, USA.
| |
Collapse
|
10
|
Augusto-Oliveira M, Arrifano GP, Delage CI, Tremblay MÈ, Crespo-Lopez ME, Verkhratsky A. Plasticity of microglia. Biol Rev Camb Philos Soc 2021; 97:217-250. [PMID: 34549510 DOI: 10.1111/brv.12797] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Microglial cells are the scions of foetal macrophages which invade the neural tube early during embryogenesis. The nervous tissue environment instigates the phenotypic metamorphosis of foetal macrophages into idiosyncratic surveilling microglia, which are generally characterised by a small cell body and highly ramified motile processes that constantly scan the nervous tissue for signs of changes in homeostasis and allow microglia to perform crucial homeostatic functions. The surveilling microglial phenotype is evolutionarily conserved from early invertebrates to humans. Despite this evolutionary conservation, microglia show substantial heterogeneity in their gene and protein expression, as well as morphological appearance. These differences are age, region and context specific and reflect a high degree of plasticity underlying the life-long adaptation of microglia, supporting the exceptional adaptive capacity of the central nervous system. Microgliocytes are essential elements of cellular network formation and refinement in the developing nervous tissue. Several distinct patrolling modes of microglial processes contribute to the formation, modification, and pruning of synapses; to the support and protection of neurones through microglial-somatic junctions; and to the control of neuronal and axonal excitability by specific microglia-axonal contacts. In pathology, microglia undergo proliferation and reactive remodelling known as microgliosis, which is context dependent, yet represents an evolutionarily conserved defence response. Microgliosis results in the emergence of multiple disease and context-specific reactive states; in addition, neuropathology is associated with the appearance of specific protective or recovery microglial forms. In summary, the plasticity of microglia supports the development and functional activity of healthy nervous tissue and provides highly sophisticated defences against disease.
Collapse
Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Charlotte Isabelle Delage
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada.,Neurology and Neurosurgery Department, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.,Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Bureau 4835, 1050 Avenue de la Médecine, Québec City, QC, G1V 0A6, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.,Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania
| |
Collapse
|
11
|
Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
| |
Collapse
|
12
|
Cserép C, Pósfai B, Dénes Á. Shaping Neuronal Fate: Functional Heterogeneity of Direct Microglia-Neuron Interactions. Neuron 2020; 109:222-240. [PMID: 33271068 DOI: 10.1016/j.neuron.2020.11.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/13/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
The functional contribution of microglia to normal brain development, healthy brain function, and neurological disorders is increasingly recognized. However, until recently, the nature of intercellular interactions mediating these effects remained largely unclear. Recent findings show microglia establishing direct contact with different compartments of neurons. Although communication between microglia and neurons involves intermediate cells and soluble factors, direct membrane contacts enable a more precisely regulated, dynamic, and highly effective form of interaction for fine-tuning neuronal responses and fate. Here, we summarize the known ultrastructural, molecular, and functional features of direct microglia-neuron interactions and their roles in brain disease.
Collapse
Affiliation(s)
- Csaba Cserép
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary
| | - Balázs Pósfai
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary; Szentágothai János Doctoral School of Neurosciences, Semmelweis University, Üllői út 26, 1085 Budapest, Hungary
| | - Ádám Dénes
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary.
| |
Collapse
|
13
|
Kaffes I, Szulzewsky F, Chen Z, Herting CJ, Gabanic B, Velázquez Vega JE, Shelton J, Switchenko JM, Ross JL, McSwain LF, Huse JT, Westermark B, Nelander S, Forsberg-Nilsson K, Uhrbom L, Maturi NP, Cimino PJ, Holland EC, Kettenmann H, Brennan CW, Brat DJ, Hambardzumyan D. Human Mesenchymal glioblastomas are characterized by an increased immune cell presence compared to Proneural and Classical tumors. Oncoimmunology 2019; 8:e1655360. [PMID: 31646100 PMCID: PMC6791439 DOI: 10.1080/2162402x.2019.1655360] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/15/2019] [Accepted: 08/09/2019] [Indexed: 12/22/2022] Open
Abstract
Glioblastoma (GBM) is the most aggressive malignant primary brain tumor in adults, with a median survival of 14.6 months. Recent efforts have focused on identifying clinically relevant subgroups to improve our understanding of pathogenetic mechanisms and patient stratification. Concurrently, the role of immune cells in the tumor microenvironment has received increasing attention, especially T cells and tumor-associated macrophages (TAM). The latter are a mixed population of activated brain-resident microglia and infiltrating monocytes/monocyte-derived macrophages, both of which express ionized calcium-binding adapter molecule 1 (IBA1). This study investigated differences in immune cell subpopulations among distinct transcriptional subtypes of GBM. Human GBM samples were molecularly characterized and assigned to Proneural, Mesenchymal or Classical subtypes as defined by NanoString nCounter Technology. Subsequently, we performed and analyzed automated immunohistochemical stainings for TAM as well as specific T cell populations. The Mesenchymal subtype of GBM showed the highest presence of TAM, CD8+, CD3+ and FOXP3+ T cells, as compared to Proneural and Classical subtypes. High expression levels of the TAM-related gene AIF1, which encodes the TAM-specific protein IBA1, correlated with a worse prognosis in Proneural GBM, but conferred a survival benefit in Mesenchymal tumors. We used our data to construct a mathematical model that could reliably identify Mesenchymal GBM with high sensitivity using a combination of the aforementioned cell-specific IHC markers. In conclusion, we demonstrated that molecularly distinct GBM subtypes are characterized by profound differences in the composition of their immune microenvironment, which could potentially help to identify tumors amenable to immunotherapy.
Collapse
Affiliation(s)
- Ioannis Kaffes
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA.,Department of Cellular Neurosciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Frank Szulzewsky
- Department of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Zhihong Chen
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA.,Discovery and Developmental Therapeutics Program, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Cameron J Herting
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | - Ben Gabanic
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Jennifer Shelton
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - Jeffrey M Switchenko
- Department of Biostatistics and Bioinformatics, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - James L Ross
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | - Leon F McSwain
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | - Jason T Huse
- Departments of Pathology and Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Bengt Westermark
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Sven Nelander
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Forsberg-Nilsson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Lene Uhrbom
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Naga Prathyusha Maturi
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Patrick J Cimino
- Department of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.,Department of Pathology, University of Washington, Seattle, WA, USA
| | - Eric C Holland
- Department of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Helmut Kettenmann
- Department of Cellular Neurosciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Cameron W Brennan
- Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Daniel J Brat
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Dolores Hambardzumyan
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA.,Discovery and Developmental Therapeutics Program, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Uweru JO, Eyo UB. A decade of diverse microglial-neuronal physical interactions in the brain (2008-2018). Neurosci Lett 2019; 698:33-38. [PMID: 30625349 PMCID: PMC6435396 DOI: 10.1016/j.neulet.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/29/2018] [Accepted: 01/01/2019] [Indexed: 12/17/2022]
Abstract
Microglia are unique cells of the central nervous system (CNS) with a distinct ontogeny and molecular profile. They are the predominant immune resident cell in the CNS. Recent studies have revealed a diversity of transient and terminal physical interactions between microglia and neurons in the vertebrate brain. In this review, we follow the historical trail of the discovery of these interactions, summarize their notable features, provide implications of these discoveries to CNS function, emphasize emerging themes along the way and peak into the future of what outstanding questions remain to move the field forward.
Collapse
Affiliation(s)
- Joseph O Uweru
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, United States; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, United States
| | - Ukpong B Eyo
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, United States; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, United States.
| |
Collapse
|
16
|
Pardo-Peña K, Lorea-Hernández JJ, Camacho-Hernández NP, Ordaz B, Villasana-Salazar B, Morales-Villagrán A, Peña-Ortega F. Hydrogen peroxide extracellular concentration in the ventrolateral medulla and its increase in response to hypoxia in vitro: Possible role of microglia. Brain Res 2018; 1692:87-99. [DOI: 10.1016/j.brainres.2018.04.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/31/2018] [Accepted: 04/25/2018] [Indexed: 12/12/2022]
|
17
|
Savage JC, Picard K, González-Ibáñez F, Tremblay MÈ. A Brief History of Microglial Ultrastructure: Distinctive Features, Phenotypes, and Functions Discovered Over the Past 60 Years by Electron Microscopy. Front Immunol 2018; 9:803. [PMID: 29922276 PMCID: PMC5996933 DOI: 10.3389/fimmu.2018.00803] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/03/2018] [Indexed: 01/01/2023] Open
Abstract
The first electron microscope was constructed in 1931. Several decades later, techniques were developed to allow the first ultrastructural analysis of microglia by transmission electron microscopy (EM). In the 50 years that followed, important roles of microglia have been identified, specifically due to the ultrastructural resolution currently available only with EM. In particular, the addition of electron-dense staining using immunohistochemical EM methods has allowed the identification of microglial cell bodies, as well as processes, which are difficult to recognize in EM, and to uncover their complex interactions with neurons and synapses. The ability to recognize neuronal, astrocytic, and oligodendrocytic compartments in the neuropil without any staining is another invaluable advantage of EM over light microscopy for studying intimate cell-cell contacts. The technique has been essential in defining microglial interactions with neurons and synapses, thus providing, among other discoveries, important insights into their roles in synaptic stripping and pruning via phagocytosis of extraneous synapses. Recent technological advances in EM including serial block-face imaging and focused-ion beam scanning EM have also facilitated automated acquisition of large tissue volumes required to reconstruct neuronal circuits in 3D at nanometer-resolution. These cutting-edge techniques which are now becoming increasingly available will further revolutionize the study of microglia across stages of the lifespan, brain regions, and contexts of health and disease. In this mini-review, we will focus on defining the distinctive ultrastructural features of microglia and the unique insights into their function that were provided by EM.
Collapse
Affiliation(s)
- Julie C. Savage
- Axe neurosciences, Centre de Recherche du CHU de Québec – Université Laval, Québec City, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
| | - Katherine Picard
- Axe neurosciences, Centre de Recherche du CHU de Québec – Université Laval, Québec City, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
| | - Fernando González-Ibáñez
- Axe neurosciences, Centre de Recherche du CHU de Québec – Université Laval, Québec City, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Axe neurosciences, Centre de Recherche du CHU de Québec – Université Laval, Québec City, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada
| |
Collapse
|
18
|
Sierra A, de Castro F, Del Río-Hortega J, Rafael Iglesias-Rozas J, Garrosa M, Kettenmann H. The "Big-Bang" for modern glial biology: Translation and comments on Pío del Río-Hortega 1919 series of papers on microglia. Glia 2018; 64:1801-40. [PMID: 27634048 DOI: 10.1002/glia.23046] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/01/2016] [Indexed: 02/06/2023]
Abstract
The word "glia" was coined in the mid-19th century and defined as "the nerve glue". For decades, it was assumed to be a uniform matrix, until cell theorists raised the "neuron doctrine" which stipulated that nervous tissue was composed of individual cells. The term "astrocytes" was introduced in the late 19th century as a synonym for glial cells, but it was Santiago Ramón y Cajal who defined a "third element" distinct from glial cells (astrocytes) and neurons. It was not until 1919 when Pío del Río-Hortega, an alumnus of the Cajal School, introduced the modern terms we use today, and thoroughly described both "oligodendrocytes" and "microglia" to clearly distinguish them from astrocytes. In a series of four papers published that year in Spanish, Río-Hortega described the distribution and morphological phenotype of microglia. He also noted that these cells were the origin of the rod cells described earlier in pathologic tissue, and recognized that resting microglia transformed into an ameboid phenotype in different types of brain diseases and pathologies. He also noted the mesodermal origin of these cells and recognized their phagocytic capacity. We here provide the first English translation of these landmark series of papers, which paved the way for modern glial research. To heighten the value and accessibility of these classic papers and their original figures, an introduction to this critical period of neuroscience is provided, along with unpublished photographs. By adding comments to the translated text, we provide sufficient context so that contemporary scientists may fully appreciate it. GLIA 2016;64:1801-1840.
Collapse
Affiliation(s)
- Amanda Sierra
- Glial Cell Biology Lab, Achucarro Basque Center for Neuroscience, Zamudio, Bizkaia, Spain. .,Ikerbasque Foundation, Bilbao, Bizkaia, Spain. .,Department of Neuroscience, Faculty of Medicine, University of the Basque Country EHU/UPV, Leioa, Bizkaia, Spain.
| | | | - Juan Del Río-Hortega
- Department of Cell Biology, Histology and Pharmacology, Faculty of Medicine, University of Valladolid, Spain
| | | | | | - Helmut Kettenmann
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| |
Collapse
|
19
|
Matyash M, Zabiegalov O, Wendt S, Matyash V, Kettenmann H. The adenosine generating enzymes CD39/CD73 control microglial processes ramification in the mouse brain. PLoS One 2017; 12:e0175012. [PMID: 28376099 PMCID: PMC5380357 DOI: 10.1371/journal.pone.0175012] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/20/2017] [Indexed: 02/03/2023] Open
Abstract
Microglial cells invade the brain as amoeboid precursors and acquire a highly ramified morphology in the postnatal brain. Microglia express all essential purinergic elements such as receptors, nucleoside transporters and ecto-enzymes, including CD39 (NTPDase1) and CD73 (5'-nucleotidase), which sequentially degrade extracellular ATP to adenosine. Here, we show that constitutive deletion of CD39 and CD73 or both caused an inhibition of the microglia ramified phenotype in the brain with a reduction in the length of processes, branching frequency and number of intersections with Sholl spheres. In vitro, unlike wild-type microglia, cd39-/- and cd73-/- microglial cells were less complex and did not respond to ATP with the transformation into a more ramified phenotype. In acute brain slices, wild-type microglia retracted approximately 50% of their processes within 15 min after slicing of the brain, and this phenomenon was augmented in cd39-/- mice; moreover, the elongation of microglial processes towards the source of ATP or towards a laser lesion was observed only in wild-type but not in cd39-/- microglia. An elevation of extracellular adenosine 1) by the inhibition of adenosine transport with dipyridamole, 2) by application of exogenous adenosine or 3) by degradation of endogenous ATP/ADP with apyrase enhanced spontaneous and ATP-induced ramification of cd39-/- microglia in acute brain slices and facilitated the transformation of cd39-/- and cd73-/- microglia into a ramified process-bearing phenotype in vitro. These data indicate that under normal physiological conditions, CD39 and CD73 nucleotidases together with equilibrative nucleoside transporter 1 (ENT1) control the fate of extracellular adenosine and thereby the ramification of microglial processes.
Collapse
Affiliation(s)
- Marina Matyash
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Oleksandr Zabiegalov
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Stefan Wendt
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Vitali Matyash
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- * E-mail:
| |
Collapse
|
20
|
Abstract
As the immune-competent cells of the brain, microglia play an increasingly important role in maintaining normal brain function. They invade the brain early in development, transform into a highly ramified phenotype, and constantly screen their environment. Microglia are activated by any type of pathologic event or change in brain homeostasis. This activation process is highly diverse and depends on the context and type of the stressor or pathology. Microglia can strongly influence the pathologic outcome or response to a stressor due to the release of a plethora of substances, including cytokines, chemokines, and growth factors. They are the professional phagocytes of the brain and help orchestrate the immunological response by interacting with infiltrating immune cells. We describe here the diversity of microglia phenotypes and their responses in health, aging, and disease. We also review the current literature about the impact of lifestyle on microglia responses and discuss treatment options that modulate microglial phenotypes.
Collapse
Affiliation(s)
- Susanne A Wolf
- Cellular Neurosciences, Max Delbrück Centre for Molecular Medicine in the Helmholtz Association, Berlin 13092, Germany;
| | - H W G M Boddeke
- Department of Neuroscience, University of Groningen, University Medical Center Groningen, Groningen 9713, The Netherlands
| | - Helmut Kettenmann
- Cellular Neurosciences, Max Delbrück Centre for Molecular Medicine in the Helmholtz Association, Berlin 13092, Germany;
| |
Collapse
|