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Jiao H, Kalsbeek A, Yi CX. Microglia, circadian rhythm and lifestyle factors. Neuropharmacology 2024; 257:110029. [PMID: 38852838 DOI: 10.1016/j.neuropharm.2024.110029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/30/2024] [Accepted: 06/03/2024] [Indexed: 06/11/2024]
Abstract
Microglia, a vital homeostasis-keeper of the central nervous system, perform critical functions such as synaptic pruning, clearance of cellular debris, and participation in neuroinflammatory processes. Recent research has shown that microglia exhibit strong circadian rhythms that not only actively regulate their own immune activity, but also affect neuronal function. Disruptions of the circadian clock have been linked to a higher risk of developing a variety of diseases. In this article we will provide an overview of how lifestyle factors impact microglial function, with a focus on disruptions caused by irregular sleep-wake patterns, reduced physical activity, and eating at the wrong time-of-day. We will also discuss the potential connection between these lifestyle factors, disrupted circadian rhythms, and the role of microglia in keeping brain health. This article is part of the Special Issue on "Microglia".
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Affiliation(s)
- Han Jiao
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology and Metabolism, Amsterdam, the Netherlands; Department of Clinical Chemistry, Laboratory of Endocrinology, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology and Metabolism, Amsterdam, the Netherlands; Department of Clinical Chemistry, Laboratory of Endocrinology, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology and Metabolism, Amsterdam, the Netherlands; Department of Clinical Chemistry, Laboratory of Endocrinology, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience, Amsterdam, the Netherlands.
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Cheng WY, Chan PL, Ong HY, Wong KH, Chang RCC. Systemic Inflammation Disrupts Circadian Rhythms and Diurnal Neuroimmune Dynamics. Int J Mol Sci 2024; 25:7458. [PMID: 39000563 PMCID: PMC11242289 DOI: 10.3390/ijms25137458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/27/2024] [Accepted: 07/04/2024] [Indexed: 07/16/2024] Open
Abstract
Circadian rhythms regulate physiological processes in approximately 24 h cycles, and their disruption is associated with various diseases. Inflammation may perturb circadian rhythms, though these interactions remain unclear. This study examined whether systemic inflammation induced by an intraperitoneal injection of lipopolysaccharide (LPS) could alter central and peripheral circadian rhythms and diurnal neuroimmune dynamics. Mice were randomly assigned to two groups: the saline control group and the LPS group. The diurnal expression of circadian clock genes and inflammatory cytokines were measured in the hypothalamus, hippocampus, and liver. Diurnal dynamic behaviors of microglia were also assessed. Our results revealed that the LPS perturbed circadian gene oscillations in the hypothalamus, hippocampus, and liver. Furthermore, systemic inflammation induced by the LPS could trigger neuroinflammation and perturb the diurnal dynamic behavior of microglia in the hippocampus. These findings shed light on the intricate link between inflammation and circadian disruption, underscoring their significance in relation to neurodegenerative diseases.
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Affiliation(s)
- Wai-Yin Cheng
- Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hong Kong SAR, China; (H.-Y.O.); (K.-H.W.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China;
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Po-Lam Chan
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China;
| | - Hang-Yin Ong
- Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hong Kong SAR, China; (H.-Y.O.); (K.-H.W.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China;
| | - Ka-Hing Wong
- Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hong Kong SAR, China; (H.-Y.O.); (K.-H.W.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China;
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
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3
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Green TRF, Rowe RK. Quantifying microglial morphology: an insight into function. Clin Exp Immunol 2024; 216:221-229. [PMID: 38456795 PMCID: PMC11097915 DOI: 10.1093/cei/uxae023] [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: 08/09/2023] [Revised: 01/17/2024] [Accepted: 03/06/2024] [Indexed: 03/09/2024] Open
Abstract
Microglia are specialized immune cells unique to the central nervous system (CNS). Microglia have a highly plastic morphology that changes rapidly in response to injury or infection. Qualitative and quantitative measurements of ever-changing microglial morphology are considered a cornerstone of many microglia-centric research studies. The distinctive morphological variations seen in microglia are a useful marker of inflammation and severity of tissue damage. Although a wide array of damage-associated microglial morphologies has been documented, the exact functions of these distinct morphologies are not fully understood. In this review, we discuss how microglia morphology is not synonymous with microglia function, however, morphological outcomes can be used to make inferences about microglial function. For a comprehensive examination of the reactive status of a microglial cell, both histological and genetic approaches should be combined. However, the importance of quality immunohistochemistry-based analyses should not be overlooked as they can succinctly answer many research questions.
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Affiliation(s)
- Tabitha R F Green
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
| | - Rachel K Rowe
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
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4
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Li R, Wang J, Xiong W, Luo Y, Feng H, Zhou H, Peng Y, He Y, Ye Q. The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease? Front Microbiol 2024; 15:1358179. [PMID: 38362505 PMCID: PMC10868393 DOI: 10.3389/fmicb.2024.1358179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-β plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.
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Affiliation(s)
- Ruohan Li
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Junnan Wang
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wei Xiong
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yu Luo
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huixian Feng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Heng Zhou
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Youjian Peng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yan He
- Institute of Regenerative and Translational Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
| | - Qingsong Ye
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
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5
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Le L, Miyanishi K, Tanaka J, Majewska AK. Microglial Regulation of Sleep and Wakefulness. ADVANCES IN NEUROBIOLOGY 2024; 37:243-260. [PMID: 39207696 DOI: 10.1007/978-3-031-55529-9_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Sleep serves a multitude of roles in brain maturation and function. Although the neural networks involved in sleep regulation have been extensively characterized, it is increasingly recognized that neurons are not the sole conductor orchestrating the rhythmic cycle of sleep and wakefulness. In the central nervous system, microglia have emerged as an important player in sleep regulation. Within the last two decades, microglia have gained substantial attention for carrying out numerous nonimmune tasks that are crucial for brain development and function by co-opting similar mechanisms used in their conventional immune functions. Here, we highlight the importance of microglia in sleep regulation with recent findings reporting an arrhythmic sleep/wake cycle in the absence of microglia. Although the underlying mechanisms for such regulation are still being uncovered, it is likely that microglial contributions to the rhythmic control of the sleep/wake cycle come from their influence on synaptic strength and neuronal activity. We review the current literature to provide speculative signaling pathways and suggest key questions for future research. Advancing our knowledge of the mechanistic contribution of microglia to sleep regulation will not only further our insight into this critical biological process but also be instrumental in providing novel therapeutic strategies for sleep disorders.
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Affiliation(s)
- Linh Le
- Department of Neuroscience, Del Monte Institute of Neuroscience, Center for Visual Science, Neuroscience Graduate Program, University of Rochester, Rochester, NY, USA
| | - Kazuya Miyanishi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Japan.
| | - Ania K Majewska
- Department of Neuroscience, Del Monte Institute of Neuroscience, Center for Visual Science, Neuroscience Graduate Program, University of Rochester, Rochester, NY, USA.
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Chen R, Routh BN, Gaudet AD, Fonken LK. Circadian Regulation of the Neuroimmune Environment Across the Lifespan: From Brain Development to Aging. J Biol Rhythms 2023; 38:419-446. [PMID: 37357738 PMCID: PMC10475217 DOI: 10.1177/07487304231178950] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Circadian clocks confer 24-h periodicity to biological systems, to ultimately maximize energy efficiency and promote survival in a world with regular environmental light cycles. In mammals, circadian rhythms regulate myriad physiological functions, including the immune, endocrine, and central nervous systems. Within the central nervous system, specialized glial cells such as astrocytes and microglia survey and maintain the neuroimmune environment. The contributions of these neuroimmune cells to both homeostatic and pathogenic demands vary greatly across the day. Moreover, the function of these cells changes across the lifespan. In this review, we discuss circadian regulation of the neuroimmune environment across the lifespan, with a focus on microglia and astrocytes. Circadian rhythms emerge in early life concurrent with neuroimmune sculpting of brain circuits and wane late in life alongside increasing immunosenescence and neurodegeneration. Importantly, circadian dysregulation can alter immune function, which may contribute to susceptibility to neurodevelopmental and neurodegenerative diseases. In this review, we highlight circadian neuroimmune interactions across the lifespan and share evidence that circadian dysregulation within the neuroimmune system may be a critical component in human neurodevelopmental and neurodegenerative diseases.
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Affiliation(s)
- Ruizhuo Chen
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Brandy N. Routh
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
| | - Andrew D. Gaudet
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
- Department of Psychology, The University of Texas at Austin, Austin, Texas
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, Texas
| | - Laura K. Fonken
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
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7
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Mitchell JW, Gillette MU. Development of circadian neurovascular function and its implications. Front Neurosci 2023; 17:1196606. [PMID: 37732312 PMCID: PMC10507717 DOI: 10.3389/fnins.2023.1196606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/14/2023] [Indexed: 09/22/2023] Open
Abstract
The neurovascular system forms the interface between the tissue of the central nervous system (CNS) and circulating blood. It plays a critical role in regulating movement of ions, small molecules, and cellular regulators into and out of brain tissue and in sustaining brain health. The neurovascular unit (NVU), the cells that form the structural and functional link between cells of the brain and the vasculature, maintains the blood-brain interface (BBI), controls cerebral blood flow, and surveils for injury. The neurovascular system is dynamic; it undergoes tight regulation of biochemical and cellular interactions to balance and support brain function. Development of an intrinsic circadian clock enables the NVU to anticipate rhythmic changes in brain activity and body physiology that occur over the day-night cycle. The development of circadian neurovascular function involves multiple cell types. We address the functional aspects of the circadian clock in the components of the NVU and their effects in regulating neurovascular physiology, including BBI permeability, cerebral blood flow, and inflammation. Disrupting the circadian clock impairs a number of physiological processes associated with the NVU, many of which are correlated with an increased risk of dysfunction and disease. Consequently, understanding the cell biology and physiology of the NVU is critical to diminishing consequences of impaired neurovascular function, including cerebral bleeding and neurodegeneration.
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Affiliation(s)
- Jennifer W. Mitchell
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Martha U. Gillette
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Carle-Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, United States
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Brécier A, Li VW, Smith CS, Halievski K, Ghasemlou N. Circadian rhythms and glial cells of the central nervous system. Biol Rev Camb Philos Soc 2023; 98:520-539. [PMID: 36352529 DOI: 10.1111/brv.12917] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/17/2022] [Accepted: 10/25/2022] [Indexed: 11/12/2022]
Abstract
Glial cells are the most abundant cells in the central nervous system and play crucial roles in neural development, homeostasis, immunity, and conductivity. Over the past few decades, glial cell activity in mammals has been linked to circadian rhythms, the 24-h chronobiological clocks that regulate many physiological processes. Indeed, glial cells rhythmically express clock genes that cell-autonomously regulate glial function. In addition, recent findings in rodents have revealed that disruption of the glial molecular clock could impact the entire organism. In this review, we discuss the impact of circadian rhythms on the function of the three major glial cell types - astrocytes, microglia, and oligodendrocytes - across different locations within the central nervous system. We also review recent evidence uncovering the impact of glial cells on the body's circadian rhythm. Together, this sheds new light on the involvement of glial clock machinery in various diseases.
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Affiliation(s)
- Aurélie Brécier
- Pain Chronobiology & Neuroimmunology Laboratory, Queen's University, Botterell Hall, room 754, Kingston, ON, K7L 3N6, Canada
- Department of Biomedical & Molecular Sciences, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
| | - Vina W Li
- Pain Chronobiology & Neuroimmunology Laboratory, Queen's University, Botterell Hall, room 754, Kingston, ON, K7L 3N6, Canada
- Department of Biomedical & Molecular Sciences, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
| | - Chloé S Smith
- Pain Chronobiology & Neuroimmunology Laboratory, Queen's University, Botterell Hall, room 754, Kingston, ON, K7L 3N6, Canada
- Department of Biomedical & Molecular Sciences, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
| | - Katherine Halievski
- Pain Chronobiology & Neuroimmunology Laboratory, Queen's University, Botterell Hall, room 754, Kingston, ON, K7L 3N6, Canada
| | - Nader Ghasemlou
- Pain Chronobiology & Neuroimmunology Laboratory, Queen's University, Botterell Hall, room 754, Kingston, ON, K7L 3N6, Canada
- Department of Biomedical & Molecular Sciences, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
- Department of Anesthesiology & Perioperative Medicine, 76 Stuart Street, Kingston, ON, K7L 2V7, Canada
- Centre for Neuroscience Studies, Queen's University, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
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Iweka CA, Seigneur E, Hernandez AL, Paredes SH, Cabrera M, Blacher E, Pasternak CT, Longo FM, de Lecea L, Andreasson KI. Myeloid deficiency of the intrinsic clock protein BMAL1 accelerates cognitive aging by disrupting microglial synaptic pruning. J Neuroinflammation 2023; 20:48. [PMID: 36829230 PMCID: PMC9951430 DOI: 10.1186/s12974-023-02727-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 02/10/2023] [Indexed: 02/26/2023] Open
Abstract
Aging is associated with loss of circadian immune responses and circadian gene transcription in peripheral macrophages. Microglia, the resident macrophages of the brain, also show diurnal rhythmicity in regulating local immune responses and synaptic remodeling. To investigate the interaction between aging and microglial circadian rhythmicity, we examined mice deficient in the core clock transcription factor, BMAL1. Aging Cd11bcre;Bmallox/lox mice demonstrated accelerated cognitive decline in association with suppressed hippocampal long-term potentiation and increases in immature dendritic spines. C1q deposition at synapses and synaptic engulfment were significantly decreased in aging Bmal1-deficient microglia, suggesting that BMAL1 plays a role in regulating synaptic pruning in aging. In addition to accelerated age-associated hippocampal deficits, Cd11bcre;Bmallox/lox mice also showed deficits in the sleep-wake cycle with increased wakefulness across light and dark phases. These results highlight an essential role of microglial BMAL1 in maintenance of synapse homeostasis in the aging brain.
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Affiliation(s)
- Chinyere Agbaegbu Iweka
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
| | - Erica Seigneur
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Amira Latif Hernandez
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
| | | | - Mica Cabrera
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
| | - Eran Blacher
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, 9190401, Jerusalem, Israel
| | - Connie Tsai Pasternak
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Katrin I Andreasson
- Department of Neurology and Neurological Sciences, Stanford School of Medicine, Stanford, CA, USA.
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA.
- Stanford Immunology Program, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
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10
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Guzmán-Ruiz MA, Guerrero-Vargas NN, Lagunes-Cruz A, González-González S, García-Aviles JE, Hurtado-Alvarado G, Mendez-Hernández R, Chavarría-Krauser A, Morin JP, Arriaga-Avila V, Buijs RM, Guevara-Guzmán R. Circadian modulation of microglial physiological processes and immune responses. Glia 2023; 71:155-167. [PMID: 35971989 PMCID: PMC10087862 DOI: 10.1002/glia.24261] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/11/2022] [Accepted: 08/01/2022] [Indexed: 11/09/2022]
Abstract
Microglia is considered the central nervous system (CNS) resident macrophages that establish an innate immune response against pathogens and toxins. However, the recent studies have shown that microglial gene and protein expression follows a circadian pattern; several immune activation markers and clock genes are expressed rhythmically without the need for an immune stimulus. Furthermore, microglia responds to an immune challenge with different magnitudes depending on the time of the day. This review examines the circadian control of microglia function and the possible physiological implications. For example, we discuss that synaptic prune is performed in the cortex at a certain moment of the day. We also consider the implications of daily microglial function for maintaining biological rhythms like general activity, body temperature, and food intake. We conclude that the developmental stage, brain region, and pathological state are not the only factors to consider for the evaluation of microglial functions; instead, emerging evidence indicates that circadian time as an essential aspect for a better understanding of the role of microglia in CNS physiology.
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Affiliation(s)
- Mara A Guzmán-Ruiz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Natalí N Guerrero-Vargas
- Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Alejandra Lagunes-Cruz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Shellye González-González
- Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Jesús Enrique García-Aviles
- Área de Neurociencias, Departamento de Biología de la Reproducción, Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, México City, Mexico
| | | | - Rebeca Mendez-Hernández
- Instituto Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico
| | - Anahí Chavarría-Krauser
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Jean-Pascal Morin
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Virginia Arriaga-Avila
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Ruud M Buijs
- Instituto Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico
| | - Rosalinda Guevara-Guzmán
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
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11
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Schurhoff N, Toborek M. Circadian rhythms in the blood-brain barrier: impact on neurological disorders and stress responses. Mol Brain 2023; 16:5. [PMID: 36635730 PMCID: PMC9835375 DOI: 10.1186/s13041-023-00997-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/03/2023] [Indexed: 01/14/2023] Open
Abstract
Circadian disruption has become more prevalent in society due to the increase in shift work, sleep disruption, blue light exposure, and travel via different time zones. The circadian rhythm is a timed transcription-translation feedback loop with positive regulators, BMAL1 and CLOCK, that interact with negative regulators, CRY and PER, to regulate both the central and peripheral clocks. This review highlights the functions of the circadian rhythm, specifically in the blood-brain barrier (BBB), during both healthy and pathological states. The BBB is a highly selective dynamic interface composed of CNS endothelial cells, astrocytes, pericytes, neurons, and microglia that form the neurovascular unit (NVU). Circadian rhythms modulate BBB integrity through regulating oscillations of tight junction proteins, assisting in functions of the NVU, and modulating transporter functions. Circadian disruptions within the BBB have been observed in stress responses and several neurological disorders, including brain metastasis, epilepsy, Alzheimer's disease, and Parkinson's disease. Further understanding of these interactions may facilitate the development of improved treatment options and preventative measures.
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Affiliation(s)
- Nicolette Schurhoff
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Suite 528, 1011 NW 15th Street, Miami, FL, 33155, USA
| | - Michal Toborek
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Suite 528, 1011 NW 15th Street, Miami, FL, 33155, USA.
- Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, 40-065, Katowice, Poland.
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12
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Machado da Silva MC, Iglesias LP, Candelario-Jalil E, Khoshbouei H, Moreira FA, de Oliveira ACP. Role of Microglia in Psychostimulant Addiction. Curr Neuropharmacol 2023; 21:235-259. [PMID: 36503452 PMCID: PMC10190137 DOI: 10.2174/1570159x21666221208142151] [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: 05/13/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 12/14/2022] Open
Abstract
The use of psychostimulant drugs can modify brain function by inducing changes in the reward system, mainly due to alterations in dopaminergic and glutamatergic transmissions in the mesocorticolimbic pathway. However, the etiopathogenesis of addiction is a much more complex process. Previous data have suggested that microglia and other immune cells are involved in events associated with neuroplasticity and memory, which are phenomena that also occur in addiction. Nevertheless, how dependent is the development of addiction on the activity of these cells? Although the mechanisms are not known, some pathways may be involved. Recent data have shown psychoactive substances may act directly on immune cells, alter their functions and induce various inflammatory mediators that modulate synaptic activity. These could, in turn, be involved in the pathological alterations that occur in substance use disorder. Here, we extensively review the studies demonstrating how cocaine and amphetamines modulate microglial number, morphology, and function. We also describe the effect of these substances in the production of inflammatory mediators and a possible involvement of some molecular signaling pathways, such as the toll-like receptor 4. Although the literature in this field is scarce, this review compiles the knowledge on the neuroimmune axis that is involved in the pathogenesis of addiction, and suggests some pharmacological targets for the development of pharmacotherapy.
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Affiliation(s)
- Maria Carolina Machado da Silva
- Department of Pharmacology, Neuropharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil;
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Lia Parada Iglesias
- Department of Pharmacology, Neuropsychopharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Habibeh Khoshbouei
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fabrício Araujo Moreira
- Department of Pharmacology, Neuropsychopharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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13
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Jang DY, Yang B, You MJ, Rim C, Kim HJ, Sung S, Kwon MS. Fluoxetine Decreases Phagocytic Function via REV-ERBα in Microglia. Neurochem Res 2023; 48:196-209. [PMID: 36048349 DOI: 10.1007/s11064-022-03733-7] [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: 06/24/2022] [Revised: 08/16/2022] [Accepted: 08/21/2022] [Indexed: 01/11/2023]
Abstract
Although fluoxetine (FLX) is a commonly used drug in psychiatric disorders, such as major depressive disorder, anxiety disorder, panic disorder, and obsessive-compulsive disorder, the mechanism by which FLX exerts its therapeutic effect is not completely understood. In this study, we aimed to determine the possible mechanism by which FLX focuses on microglial phagocytosis. FLX reduced phagocytic function in BV2 cells and increased REV-ERBα without affecting other microglia-related genes, such as inflammation and phagocytosis. Although FLX did not change BMAL1 protein levels, it restricted the nucleocytoplasmic transport (NCT) of BMAL1, leading to its cytosolic accumulation. REV-ERBα antagonist SR8278 rescued the decreased phagocytic activity and restricted NCT of BMAL1. We also found that REV-ERBα mediates the effect of FLX via the inhibition of phospho-ERK (pERK). The ERK inhibitor FR180204 was sufficient to reduce phagocytic function in BV2 cells and restrict the NCT of BMAL1. These results were recapitulated in the primary microglia. In conclusion, we propose that FLX decreases phagocytic function and restricts BMAL1 NCT via REV-ERBα. In addition, ERK inhibition mimics the effects of FLX on microglia.
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Affiliation(s)
- Da-Yoon Jang
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea.,Research Competency Milestones Program (RECOMP) of School of Medicine, CHA University, Seongnam-si, South Korea
| | - Bohyun Yang
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea
| | - Min-Jung You
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea
| | - Chan Rim
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea
| | - Hui-Ju Kim
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea
| | - Soyoung Sung
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea
| | - Min-Soo Kwon
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, CHA BIO COMPLEX, 335 Pangyo, Bundang-Gu, Seongnam-si, 13488, Gyeonggi-do, Republic of Korea.
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14
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Barahona RA, Morabito S, Swarup V, Green KN. Cortical diurnal rhythms remain intact with microglial depletion. Sci Rep 2022; 12:114. [PMID: 34997092 PMCID: PMC8742049 DOI: 10.1038/s41598-021-04079-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/01/2021] [Indexed: 12/15/2022] Open
Abstract
Microglia are subject to change in tandem with the endogenously generated biological oscillations known as our circadian rhythm. Studies have shown microglia harbor an intrinsic molecular clock which regulates diurnal changes in morphology and influences inflammatory responses. In the adult brain, microglia play an important role in the regulation of condensed extracellular matrix structures called perineuronal nets (PNNs), and it has been suggested that PNNs are also regulated in a circadian and diurnal manner. We sought to determine whether microglia mediate the diurnal regulation of PNNs via CSF1R inhibitor dependent microglial depletion in C57BL/6J mice, and how the absence of microglia might affect cortical diurnal gene expression rhythms. While we observe diurnal differences in microglial morphology, where microglia are most ramified at the onset of the dark phase, we do not find diurnal differences in PNN intensity. However, PNN intensity increases across many brain regions in the absence of microglia, supporting a role for microglia in the regulation of PNNs. Here, we also show that cortical diurnal gene expression rhythms are intact, with no cycling gene changes without microglia. These findings demonstrate a role for microglia in the maintenance of PNNs, but not in the maintenance of diurnal rhythms.
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Affiliation(s)
- Rocio A Barahona
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Samuel Morabito
- Mathematical, Computational and Systems Biology (MCSB) Program, University of California, Irvine, CA, USA
| | - Vivek Swarup
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA.
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15
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Cordella F, Sanchini C, Rosito M, Ferrucci L, Pediconi N, Cortese B, Guerrieri F, Pascucci GR, Antonangeli F, Peruzzi G, Giubettini M, Basilico B, Pagani F, Grimaldi A, D’Alessandro G, Limatola C, Ragozzino D, Di Angelantonio S. Antibiotics Treatment Modulates Microglia-Synapses Interaction. Cells 2021; 10:cells10102648. [PMID: 34685628 PMCID: PMC8534187 DOI: 10.3390/cells10102648] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 12/12/2022] Open
Abstract
‘Dysbiosis’ of the adult gut microbiota, in response to challenges such as infection, altered diet, stress, and antibiotics treatment has been recently linked to pathological alteration of brain function and behavior. Moreover, gut microbiota composition constantly controls microglia maturation, as revealed by morphological observations and gene expression analysis. However, it is unclear whether microglia functional properties and crosstalk with neurons, known to shape and modulate synaptic development and function, are influenced by the gut microbiota. Here, we investigated how antibiotic-mediated alteration of the gut microbiota influences microglial and neuronal functions in adult mice hippocampus. Hippocampal microglia from adult mice treated with oral antibiotics exhibited increased microglia density, altered basal patrolling activity, and impaired process rearrangement in response to damage. Patch clamp recordings at CA3-CA1 synapses revealed that antibiotics treatment alters neuronal functions, reducing spontaneous postsynaptic glutamatergic currents and decreasing synaptic connectivity, without reducing dendritic spines density. Antibiotics treatment was unable to modulate synaptic function in CX3CR1-deficient mice, pointing to an involvement of microglia–neuron crosstalk through the CX3CL1/CX3CR1 axis in the effect of dysbiosis on neuronal functions. Together, our findings show that antibiotic alteration of gut microbiota impairs synaptic efficacy, suggesting that CX3CL1/CX3CR1 signaling supporting microglia is a major player in in the gut–brain axis, and in particular in the gut microbiota-to-neuron communication pathway.
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Affiliation(s)
- Federica Cordella
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Caterina Sanchini
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Maria Rosito
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- Correspondence: (M.R.); (S.D.A.)
| | - Laura Ferrucci
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
| | - Natalia Pediconi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Barbara Cortese
- National Research Council-Nanotechnology Institute, 00185 Rome, Italy;
| | - Francesca Guerrieri
- Cancer Research Center of Lyon (CRCL), UMR Inserm U1052/CNRS 5286, 69373 Lyon, France; (F.G.); (G.R.P.)
| | - Giuseppe Rubens Pascucci
- Cancer Research Center of Lyon (CRCL), UMR Inserm U1052/CNRS 5286, 69373 Lyon, France; (F.G.); (G.R.P.)
| | - Fabrizio Antonangeli
- Department of Molecular Medicine, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
| | - Giovanna Peruzzi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | | | - Bernadette Basilico
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
| | - Francesca Pagani
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- National Research Council-Nanotechnology Institute, 00185 Rome, Italy;
| | - Alfonso Grimaldi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Giuseppina D’Alessandro
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
- IRCCS Neuromed, Via Atinese 18, 86077 Pozzilli, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Santa Lucia Foundation, European Center for Brain Research, 00143 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- Correspondence: (M.R.); (S.D.A.)
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16
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Palomino-Segura M, Hidalgo A. Circadian immune circuits. J Exp Med 2021; 218:211639. [PMID: 33372990 PMCID: PMC7774593 DOI: 10.1084/jem.20200798] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/30/2022] Open
Abstract
Immune responses are gated to protect the host against specific antigens and microbes, a task that is achieved through antigen- and pattern-specific receptors. Less appreciated is that in order to optimize responses and to avoid collateral damage to the host, immune responses must be additionally gated in intensity and time. An evolutionary solution to this challenge is provided by the circadian clock, an ancient time-keeping mechanism that anticipates environmental changes and represents a fundamental property of immunity. Immune responses, however, are not exclusive to immune cells and demand the coordinated action of nonhematopoietic cells interspersed within the architecture of tissues. Here, we review the circadian features of innate immunity as they encompass effector immune cells as well as structural cells that orchestrate their responses in space and time. We finally propose models in which the central clock, structural elements, and immune cells establish multidirectional circadian circuits that may shape the efficacy and strength of immune responses and other physiological processes.
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Affiliation(s)
- Miguel Palomino-Segura
- Area of Cell and Developmental Biology, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Andrés Hidalgo
- Area of Cell and Developmental Biology, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
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17
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Ryder MI, Xenoudi P. Alzheimer disease and the periodontal patient: New insights, connections, and therapies. Periodontol 2000 2021; 87:32-42. [PMID: 34463981 DOI: 10.1111/prd.12389] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Loss of cognitive function in the aging population, particular those with Alzheimer disease, presents unique challenges to health practitioners. For the dental practitioner these include management of periodontal diseases, caries, and other dental conditions in this special population. It is well established in the cognitively impaired patient that a lack of adherence to dental hygiene routines and professional care leads to increases in the prevalence and severity of these dental conditions, leading to increased loss of teeth. More recent evidence has indicated a possible role of the microbiota of dental plaque associated with periodontal diseases in the development and progression of Alzheimer disease, thereby supporting a two-way interaction of these two diseases. New therapies are needed to address the potential upstream events that may precede overt signs of Alzheimer disease. One of these approaches would be to target these various bacterial, viral, and other microbial pathogens associated with periodontal disease that can translocate into the bloodstream and then to distal sites, such as the brain. Such microbial translocation would lead to local inflammation and buildup of the hallmark signs of Alzheimer disease, including amyloid beta deposits, tau fragmentation and tangles, breakdown of host protective molecules, such as the apolipoproteins, and neuron toxicity. In this review, evidence for the biological basis of the role of the periodontal disease microflora on the initiation and progression of Alzheimer disease will be presented with a focus on the potential role of the keystone pathogen Porphyromonas gingivalis with its family of gingipain enzymes. The various mechanisms for which P. gingivalis gingipains may contribute to the initiation and progression of Alzheimer disease are presented. Small-molecule inhibitors of these gingipains and their effects on reducing biological markers of Alzheimer disease may have beneficial effects for the initiation and progression of loss of cognitive function in Alzheimer disease. In addition to these targeted therapies for specific periodontal pathogens, considerations for the dental practitioner in applying more general approaches to reducing the periodontal plaque microflora in the management of the cognitively impaired patient are discussed for this special population.
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Affiliation(s)
- Mark I Ryder
- Division of Periodontology, Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco, California, USA
| | - Pinelopi Xenoudi
- College of Dental Medicine, California Northstate University, Elk Grove, California, USA
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18
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Bregaint S, Boyer E, Fong SB, Meuric V, Bonnaure-Mallet M, Jolivet-Gougeon A. Porphyromonas gingivalis outside the oral cavity. Odontology 2021; 110:1-19. [PMID: 34410562 DOI: 10.1007/s10266-021-00647-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 07/31/2021] [Indexed: 12/14/2022]
Abstract
Porphyromonas gingivalis, a Gram-negative anaerobic bacillus present in periodontal disease, is considered one of the major pathogens in periodontitis. A literature search for English original studies, case series and review articles published up to December 2019 was performed using the MEDLINE, PubMed and GoogleScholar databases, with the search terms "Porphyromonas gingivalis" AND the potentially associated condition or systemic disease Abstracts and full text articles were used to make a review of published research literature on P. gingivalis outside the oral cavity. The main points of interest of this narrative review were: (i) a potential direct action of the bacterium and not the systemic effects of the inflammatory acute-phase response induced by the periodontitis, (ii) the presence of the bacterium (viable or not) in the organ, or (iii) the presence of its virulence factors. Virulence factors (gingipains, capsule, fimbriae, hemagglutinins, lipopolysaccharide, hemolysin, iron uptake transporters, toxic outer membrane blebs/vesicles, and DNA) associated with P. gingivalis can deregulate certain functions in humans, particularly host immune systems, and cause various local and systemic pathologies. The most recent studies linking P. gingivalis to systemic diseases were discussed, remembering particularly the molecular mechanisms involved in different infections, including cerebral, cardiovascular, pulmonary, bone, digestive and peri-natal infections. Recent involvement of P. gingivalis in neurological diseases has been demonstrated. P. gingivalis modulates cellular homeostasis and increases markers of inflammation. It is also a factor in the oxidative stress involved in beta-amyloid production.
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Affiliation(s)
- Steeve Bregaint
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France
| | - Emile Boyer
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France.,Teaching Hospital Pontchaillou, 2 rue Henri Le Guilloux, 35033, Rennes, France
| | - Shao Bing Fong
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France
| | - Vincent Meuric
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France.,Teaching Hospital Pontchaillou, 2 rue Henri Le Guilloux, 35033, Rennes, France
| | - Martine Bonnaure-Mallet
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France.,Teaching Hospital Pontchaillou, 2 rue Henri Le Guilloux, 35033, Rennes, France
| | - Anne Jolivet-Gougeon
- Microbiology, INSERM, INRAE, CHU Rennes, Institut NUMECAN (Nutrition Metabolisms and Cancer), Université de Rennes, U1241, 2, avenue du Professeur Léon Bernard, 35043, Rennes, France. .,Teaching Hospital Pontchaillou, 2 rue Henri Le Guilloux, 35033, Rennes, France.
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19
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Liu H, Wang X, Chen L, Chen L, Tsirka SE, Ge S, Xiong Q. Microglia modulate stable wakefulness via the thalamic reticular nucleus in mice. Nat Commun 2021; 12:4646. [PMID: 34330901 PMCID: PMC8324895 DOI: 10.1038/s41467-021-24915-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 07/15/2021] [Indexed: 01/03/2023] Open
Abstract
Microglia are important for brain homeostasis and immunity, but their role in regulating vigilance remains unclear. We employed genetic, physiological, and metabolomic methods to examine microglial involvement in the regulation of wakefulness and sleep. Microglial depletion decreased stable nighttime wakefulness in mice by increasing transitions between wakefulness and non-rapid eye movement (NREM) sleep. Metabolomic analysis revealed that the sleep-wake behavior closely correlated with diurnal variation of the brain ceramide, which disappeared in microglia-depleted mice. Ceramide preferentially influenced microglia in the thalamic reticular nucleus (TRN), and local depletion of TRN microglia produced similar impaired wakefulness. Chemogenetic manipulations of anterior TRN neurons showed that they regulated transitions between wakefulness and NREM sleep. Their firing capacity was suppressed by both microglial depletion and added ceramide. In microglia-depleted mice, activating anterior TRN neurons or inhibiting ceramide production both restored stable wakefulness. These findings demonstrate that microglia can modulate stable wakefulness through anterior TRN neurons via ceramide signaling.
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Affiliation(s)
- Hanxiao Liu
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Xinxing Wang
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Lu Chen
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Liang Chen
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Stella E Tsirka
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Shaoyu Ge
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Qiaojie Xiong
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA.
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20
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Ding D, Wang X, Li Q, Li L, Wu J. Research on the Glial-Lymphatic System and Its Relationship With Alzheimer's Disease. Front Neurosci 2021; 15:605586. [PMID: 34220413 PMCID: PMC8242204 DOI: 10.3389/fnins.2021.605586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 05/06/2021] [Indexed: 11/13/2022] Open
Abstract
Metabolic waste clearance is essential to maintain body homeostasis, in which the lymphatic system plays a vital role. Conversely, in recent years, studies have identified the glial-lymphatic system in the brain, which primarily comprises the inflow of fluid along the para-arterial space. Aquaporin-4 mediates the convection of interstitial fluid in the brain and outflow along the paravenous space. β-Amyloid deposition is a characteristic pathological change in Alzheimer's disease, and some studies have found that the glial-lymphatic system plays an important role in its clearance. Thus, the glial-lymphatic system may influence Alzheimer's disease severity and outcome; therefore, this review summarizes the current and available research on the glial-lymphatic system and Alzheimer's disease.
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Affiliation(s)
- Danhua Ding
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xinyu Wang
- Department of Rheumatology, Peking University Third Hospital, Beijing, China
| | - Qianqian Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Lanjun Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jun Wu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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21
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Sominsky L, Dangel T, Malik S, De Luca SN, Singewald N, Spencer SJ. Microglial ablation in rats disrupts the circadian system. FASEB J 2021; 35:e21195. [PMID: 33200466 DOI: 10.1096/fj.202001555rr] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 01/26/2023]
Abstract
Microglia, the key neuroimmune cells of the central nervous system, are best known for their function in defending an individual from pathogens and injury. Recent findings, including our own, suggest microglia also have several immune-independent roles, including in regulating satiety, promoting memory, and modifying pain responses. Many of these microglia-associated functions are affected by circadian rhythmicity, thus, varying substantially depending upon the time of day. To gain further insight into this link, we used a Cx3cr1-Dtr transgenic Wistar rat model to acutely deplete microglia and examined if this could lead to a disruption in diurnal temperature, metabolism, and activity measures. We also examined if differences in the physiological rhythms corresponded with changes in the expression of key circadian rhythm-regulating genes and proteins. Our data show that in the absence of microglia there is a pronounced disruption of diurnal rhythms in several domains consistent with a shift toward the inactive phase, in conjunction with changes in circadian rhythm-regulating genes and proteins. These data suggest microglia are involved in the regulation of circadian rhythms and indicate an exciting potential to manipulate these cells to improve disrupted circadian rhythms such as with shift-work or jet-lag.
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Affiliation(s)
- Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Tamara Dangel
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Sajida Malik
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Simone N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
- ARC Centre of Excellence for Nanoscale Biophotonics, RMIT University, Melbourne, VIC, Australia
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22
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Deurveilher S, Golovin T, Hall S, Semba K. Microglia dynamics in sleep/wake states and in response to sleep loss. Neurochem Int 2020; 143:104944. [PMID: 33359188 DOI: 10.1016/j.neuint.2020.104944] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/15/2020] [Accepted: 12/20/2020] [Indexed: 12/22/2022]
Abstract
Sleep has an essential role for optimal brain function, but the cellular substrates for sleep regulation are not fully understood. Microglia, the immune cells of the brain, have gained increasingly more attention over the last two decades for their important roles in various brain functions that extend beyond their well-known immune function, including brain development, neuronal protection, and synaptic plasticity. Here we review recent advances in understanding: i) morphological and phenotypic dynamics of microglia including process motility/growth and gene/protein expression, and ii) microglia-neuron interactions including phagocytosis and contact at synapses which alters neuronal circuit activity, both under physiological state in the adult brain. We discuss how the microglia-neuron interactions particularly at synapses could influence microglia and neuronal activities across circadian cycles and sleep/wake states. We also review recent findings on how microglia respond to sleep loss. We conclude by pointing out key questions and proposing suggestions for future research to better understand the role of microglia in sleep regulation, sleep homeostasis, and the function of sleep.
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Affiliation(s)
- Samuel Deurveilher
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Tatjana Golovin
- Department of Physiology & Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Shannon Hall
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kazue Semba
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Psychology & Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.
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23
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Nakanishi H, Ni J, Nonaka S, Hayashi Y. Microglial circadian clock regulation of microglial structural complexity, dendritic spine density and inflammatory response. Neurochem Int 2020; 142:104905. [PMID: 33217515 DOI: 10.1016/j.neuint.2020.104905] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 02/08/2023]
Abstract
Cortical microglia exhibit a ramified shape during sleep, while they have a hyper-ramified shape during wakefulness, which is characterized by their longer processes with increased branching points. The microglial molecular circadian clock regulates expressions of both cathepsin S (CatS) and P2Y12 receptors in the brain with a peak at zeitgeber time 14 (2 h after beginning of the dark phase). We postulated that these two microglia-specific molecules contribute to diurnal alterations of microglial shapes and neuronal activities in the cerebral cortex. During wakefulness, CatS secreted from cortical microglia may be involved in P2Y12 receptor-dependent process extension. Secreted CatS subsequently degrades the perineuronal nets, initiating the downscaling of both spine density and synaptic strength of cortical neurons toward the beginning of sleep. The downscaling of both spine density and synaptic strength of cortical neurons during sleep could improve signal-to-noise, which would benefit memory consolidation, or allow for new learning to occur during subsequent waking. Furthermore, disruption of CatS induces the sleep disturbance and impaired social interaction in mice. Moreover, the microglial clock system disruption may also play a role in the early pathogenesis of Alzheimer's disease. The reduced expression of BMAL1 in cortical microglia caused by oligomeric amyloid β may induce the increased presence of inflammatory phenotype through a reduction in RORα, which in turn reduced IκBα and enhanced NF-κB activation. These observations suggest that the microglial clock system disruption contribute to pathogeneses of sleep disturbance, impaired social interaction and cognitive impairment. Therefore, the growing understanding of the microglial circadian molecular clock might aid in the development of novel pharmacological interventions against both neuropsychiatric and neurodegenerative disorders.
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Affiliation(s)
- Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan.
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy in the Ministry of Industry and Information Technology, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan
| | - Yoshinori Hayashi
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
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24
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Martinez-Tapia RJ, Estrada-Rojo F, Lopez-Aceves TG, Rodríguez-Mata V, Perez-Torres A, Barajas-Martinez A, Garcia-Velasco S, Ugalde-Muñiz P, Navarro L. Diurnal Variation Induces Neurobehavioral and Neuropathological Differences in a Rat Model of Traumatic Brain Injury. Front Neurosci 2020; 14:564992. [PMID: 33132827 PMCID: PMC7550533 DOI: 10.3389/fnins.2020.564992] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/25/2020] [Indexed: 01/21/2023] Open
Abstract
Traumatic brain injury (TBI) induces two types of brain damage: primary and secondary. Damage initiates a series of pathophysiological processes, such as metabolic crisis, excitotoxicity with oxidative stress-induced damage, and neuroinflammation. The long-term perpetuation of these processes has deleterious consequences for neuronal function. However, it remains to be elucidated further whether physiological variation in the brain microenvironment, depending on diurnal variations, influences the damage, and consequently, exerts a neuroprotective effect. Here, we established an experimental rat model of TBI and evaluated the effects of TBI induced at two different time points of the light–dark cycle. Behavioral responses were assessed using a 21-point neurobehavioral scale and the cylinder test. Morphological damage was assessed in different regions of the central nervous system. We found that rats that experienced a TBI during the dark hours had better behavioral performance than those injured during the light hours. Differences in behavioral performance correlated with less morphological damage in the perilesional zone. Moreover, certain brain areas (CA1 and dentate gyrus subregions of the hippocampus) were less prone to damage in rats that experienced a TBI during the dark hours. Our results suggest that diurnal variation is a crucial determinant of TBI outcome, and the hour of the day at which an injury occurs should be considered for future research.
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Affiliation(s)
| | - Francisco Estrada-Rojo
- Departamento de Fisiologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
| | - Teresita Guadalupe Lopez-Aceves
- Programa Regional de Posgrado en Biotecnologia, Facultad de Ciencias Quimico Biologicas, Universidad Autonoma de Sinaloa, Culiacán, Mexico
| | - Veronica Rodríguez-Mata
- Departamento de Biologia Celular y Tisular, Facultad de Medicina, Universidad Nacional Autonoma de México, Mexico City, Mexico
| | - Armando Perez-Torres
- Departamento de Biologia Celular y Tisular, Facultad de Medicina, Universidad Nacional Autonoma de México, Mexico City, Mexico
| | - Antonio Barajas-Martinez
- Departamento de Fisiologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
| | - Stephany Garcia-Velasco
- Departamento de Fisiologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
| | - Perla Ugalde-Muñiz
- Departamento de Fisiologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
| | - Luz Navarro
- Departamento de Fisiologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
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25
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Abstract
While neurons and circuits are almost unequivocally considered to be the computational units and actuators of behavior, a complete understanding of the nervous system must incorporate glial cells. Far beyond a copious but passive substrate, glial influence is inextricable from neuronal physiology, whether during developmental guidance and synaptic shaping or through the trophic support, neurotransmitter and ion homeostasis, cytokine signaling and immune function, and debris engulfment contributions that this class provides throughout an organism's life. With such essential functions, among a growing literature of nuanced roles, it follows that glia are consequential to behavior in adult animals, with novel genetic tools allowing for the investigation of these phenomena in living organisms. We discuss here the relevance of glia for maintaining circadian rhythms and also for serving functions of sleep.
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Affiliation(s)
- Gregory Artiushin
- Chronobiology and Sleep Institute, Perelman School of Medicine, and Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Amita Sehgal
- Chronobiology and Sleep Institute, Perelman School of Medicine, and Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
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26
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Pagani F, Testi C, Grimaldi A, Corsi G, Cortese B, Basilico B, Baiocco P, De Panfilis S, Ragozzino D, Di Angelantonio S. Dimethyl Fumarate Reduces Microglia Functional Response to Tissue Damage and Favors Brain Iron Homeostasis. Neuroscience 2020; 439:241-254. [DOI: 10.1016/j.neuroscience.2019.10.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/08/2019] [Accepted: 10/23/2019] [Indexed: 01/20/2023]
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27
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Ward H, West SJ. Microglia: sculptors of neuropathic pain? ROYAL SOCIETY OPEN SCIENCE 2020; 7:200260. [PMID: 32742693 PMCID: PMC7353970 DOI: 10.1098/rsos.200260] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/01/2020] [Indexed: 05/02/2023]
Abstract
Neuropathic pain presents a huge societal and individual burden. The limited efficacy of current analgesics, diagnostic markers and clinical trial outcome measures arises from an incomplete understanding of the underlying mechanisms. A large and growing body of evidence has established the important role of microglia in the onset and possible maintenance of neuropathic pain, and these cells may represent an important target for future therapy. Microglial research has further revealed their important role in structural remodelling of the nervous system. In this review, we aim to explore the evidence for microglia in sculpting nervous system structure and function, as well as their important role in neuropathic pain, and finally integrate these studies to synthesize a new model for microglia in somatosensory circuit remodelling, composed of six key and inter-related mechanisms. Summarizing the mechanisms through which microglia modulate nervous system structure and function helps to frame a better understanding of neuropathic pain, and provide a clear roadmap for future research.
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Affiliation(s)
- Harry Ward
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Steven J. West
- Sainsbury Wellcome Centre, University College London, 25 Howland St, London WC1E 6BT, UK
- Author for correspondence: Steven J. West e-mail:
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28
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De Luca SN, Soch A, Sominsky L, Nguyen TX, Bosakhar A, Spencer SJ. Glial remodeling enhances short-term memory performance in Wistar rats. J Neuroinflammation 2020; 17:52. [PMID: 32028971 PMCID: PMC7006153 DOI: 10.1186/s12974-020-1729-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/28/2020] [Indexed: 12/16/2022] Open
Abstract
Background Microglia play a key role in neuronal circuit and synaptic maturation in the developing brain. In the healthy adult, however, their role is less clear: microglial hyperactivation in adults can be detrimental to memory due to excessive synaptic pruning, yet learning and memory can also be impaired in the absence of these cells. In this study, we therefore aimed to determine how microglia contribute to short-term memory in healthy adults. Methods To this end, we developed a Cx3cr1-Dtr transgenic Wistar rat with a diphtheria toxin receptor (Dtr) gene inserted into the fractalkine receptor (Cx3cr1) promoter, expressed on microglia and monocytes. This model allows acute microglial and monocyte ablation upon application of diphtheria toxin, enabling us to directly assess microglia’s role in memory. Results Here, we show that short-term memory in the novel object and place recognition tasks is entirely unaffected by acute microglial ablation. However, when microglia repopulate the brain after depletion, learning and memory performance in these tasks is improved. This transitory memory enhancement is associated with an ameboid morphology in the newly repopulated microglial cells and increased astrocyte density that are linked with a higher density of mature hippocampal synaptic spines and differences in pre- and post-synaptic markers. Conclusions These data indicate that glia play a complex role in the healthy adult animal in supporting appropriate learning and memory and that subtle changes to the function of these cells may strategically enhance memory.
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Affiliation(s)
- Simone N De Luca
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Alita Soch
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Luba Sominsky
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Thai-Xinh Nguyen
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Abdulhameed Bosakhar
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences RMIT University, Melbourne, VIC, 3083, Australia. .,ARC Centre of Excellence for Nanoscale Biophotonics, RMIT University, Melbourne, VIC, Australia.
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29
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Lee N, Jae Y, Kim M, Cho T, Lee C, Hong YR, Hyeon DY, Ahn S, Kwon H, Kim K, Jung JH, Chae S, Shin JO, Bok J, Byun Y, Hwang D, Koo J. A pathogen-derived metabolite induces microglial activation via odorant receptors. FEBS J 2020; 287:3841-3870. [PMID: 32003140 DOI: 10.1111/febs.15234] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/10/2019] [Accepted: 01/27/2020] [Indexed: 12/21/2022]
Abstract
Microglia (MG), the principal neuroimmune sentinels in the brain, continuously sense changes in their environment and respond to invading pathogens, toxins, and cellular debris, thereby affecting neuroinflammation. Microbial pathogens produce small metabolites that influence neuroinflammation, but the molecular mechanisms that determine whether pathogen-derived small metabolites affect microglial activation of neuroinflammation remain to be elucidated. We hypothesized that odorant receptors (ORs), the largest subfamily of G protein-coupled receptors, are involved in microglial activation by pathogen-derived small metabolites. We found that MG express high levels of two mouse ORs, Olfr110 and Olfr111, which recognize a pathogenic metabolite, 2-pentylfuran, secreted by Streptococcus pneumoniae. These interactions activate MG to engage in chemotaxis, cytokine production, phagocytosis, and reactive oxygen species generation. These effects were mediated through the Gαs -cyclic adenosine monophosphate-protein kinase A-extracellular signal-regulated kinase and Gβγ -phospholipase C-Ca2+ pathways. Taken together, our results reveal a novel interplay between the pathogen-derived metabolite and ORs, which has major implications for our understanding of microglial activation by pathogen recognition. DATABASE: Model data are available in the PMDB database under the accession number PM0082389.
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Affiliation(s)
- NaHye Lee
- Department of New Biology, DGIST, Daegu, Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Korea
| | - YoonGyu Jae
- Department of New Biology, DGIST, Daegu, Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Korea
| | - Minhyung Kim
- Center for Plant Aging Research, DGIST, Daegu, Korea
| | - TaeHo Cho
- Department of New Biology, DGIST, Daegu, Korea
| | - ChaeEun Lee
- Department of New Biology, DGIST, Daegu, Korea
| | - Yu Ri Hong
- Department of New Biology, DGIST, Daegu, Korea
| | | | - Sanghyun Ahn
- Center for Plant Aging Research, DGIST, Daegu, Korea
| | - Hongmok Kwon
- College of Pharmacy, Korea University, Sejong, Korea
| | - Kyul Kim
- College of Pharmacy, Korea University, Sejong, Korea
| | - Jae Hoon Jung
- Center for Plant Aging Research, DGIST, Daegu, Korea
| | - Sehyun Chae
- Center for Plant Aging Research, DGIST, Daegu, Korea
| | - Jeong-Oh Shin
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
| | - Youngjoo Byun
- College of Pharmacy, Korea University, Sejong, Korea
| | - Daehee Hwang
- Center for Plant Aging Research, DGIST, Daegu, Korea.,Department of Biological Sciences, Seoul National University, Korea
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30
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Microglia, Lifestyle Stress, and Neurodegeneration. Immunity 2020; 52:222-240. [PMID: 31924476 DOI: 10.1016/j.immuni.2019.12.003] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
Recent years have witnessed a revolution in our understanding of microglia biology, including their major role in the etiology and pathogenesis of neurodegenerative diseases. Technological advances have enabled the identification of microglial signatures in health and disease, including the development of new models to investigate and manipulate human microglia in vivo in the context of disease. In parallel, genetic association studies have identified several gene risk factors associated with Alzheimer's disease that are specifically or highly expressed by microglia in the central nervous system (CNS). Here, we discuss evidence for the effect of stress, diet, sleep patterns, physical activity, and microbiota composition on microglia biology and consider how lifestyle might influence an individual's predisposition to neurodegenerative diseases. We discuss how different lifestyles and environmental factors might regulate microglia, potentially leading to increased susceptibility to neurodegenerative disease, and we highlight the need to investigate the contribution of modern environmental factors on microglia modulation in neurodegeneration.
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31
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Differences in Diurnal Variation of Immune Responses in Microglia and Macrophages: Review and Perspectives. Cell Mol Neurobiol 2019; 40:301-309. [PMID: 31549296 DOI: 10.1007/s10571-019-00736-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/07/2019] [Indexed: 12/18/2022]
Abstract
Biological rhythms, especially those that last close to 24 h, better known as circadian rhythms, are highly regulated phenomena, maintained throughout evolution in various organisms which allow organisms to predict, prepare for, and adapt to environmental changes. One of these phenomena that exhibit biological rhythms is the immune response to external agents. Immune cells (neutrophils, lymphocytes, macrophages, among others), as well as their mediators such as cytokines and chemokines, undergo variations in tissue and blood concentrations during the day. These rhythms are still being elucidated in microglia, the resident macrophages of the central nervous system, but since these cells share a common origin with peripheral macrophages, they are expected to behave similarly. In this review, we will discuss the possible differences in the responses between peripheral macrophages and microglia, their relationship with the circadian clock, and whether these rhythms can influence therapeutic choices.
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32
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Ni J, Wu Z, Meng J, Saito T, Saido TC, Qing H, Nakanishi H. An impaired intrinsic microglial clock system induces neuroinflammatory alterations in the early stage of amyloid precursor protein knock-in mouse brain. J Neuroinflammation 2019; 16:173. [PMID: 31470863 PMCID: PMC6716829 DOI: 10.1186/s12974-019-1562-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 08/20/2019] [Indexed: 02/05/2023] Open
Abstract
Background Disturbances in clock genes affect almost all patients with Alzheimer’s disease (AD), as evidenced by their altered sleep/wake cycle, thermoregulation, and exacerbation of cognitive impairment. As microglia-mediated neuroinflammation proved to be a driver of AD rather than a result of the disease, in this study, we evaluated the relationship between clock gene disturbance and neuroinflammation in microglia and their contribution to the onset of AD. Methods In this study, the expression of clock genes and inflammatory-related genes was examined in MACS microglia isolated from 2-month-old amyloid precursor protein knock-in (APP-KI) and wild-type (WT) mice using cap analysis gene expression (CAGE) deep sequencing and RT-PCR. The effects of clock gene disturbance on neuroinflammation and relevant memory changes were examined in 2-month-old APP-KI and WT mice after injection with SR9009 (a synthetic agonist for REV-ERB). The microglia morphology was studied by staining, neuroinflammation was examined by Western blotting, and cognitive changes were examined by Y-maze and novel object recognition tests. Results CLOCK/BMAL1-driven transcriptional negative feedback loops were impaired in the microglia from 2-month-old APP-KI mice. Pro-inflammatory genes in microglia isolated from APP-KI mice were significantly higher than those isolated from WT mice at Zeitgeber time 14. The expression of pro-inflammatory genes was positively associated with NF-κB activation and negatively associated with the BMAL1 expression. SR9009 induced the activation of microglia, the increased expression of pro-inflammatory genes, and cognitive decline in 2-month-old APP-KI mice. Conclusion Clock gene disturbance in microglia is involved in the early onset of AD through the induction of chronic neuroinflammation, which may be a new target for preventing or slowing AD. Electronic supplementary material The online version of this article (10.1186/s12974-019-1562-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junjun Ni
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
| | - Zhou Wu
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Jie Meng
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako, 351-0198, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako, 351-0198, Japan
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, 100081, People's Republic of China
| | - Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan.
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33
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Huang L, Otrokocsi L, Sperlágh B. Role of P2 receptors in normal brain development and in neurodevelopmental psychiatric disorders. Brain Res Bull 2019; 151:55-64. [PMID: 30721770 DOI: 10.1016/j.brainresbull.2019.01.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/17/2019] [Accepted: 01/19/2019] [Indexed: 12/19/2022]
Abstract
The purinergic signaling system, including P2 receptors, plays an important role in various central nervous system (CNS) disorders. Over the last few decades, a substantial amount of accumulated data suggest that most P2 receptor subtypes (P2X1, 2, 3, 4, 6, and 7, and P2Y1, 2, 6, 12, and 13) regulate neuronal/neuroglial developmental processes, such as proliferation, differentiation, migration of neuronal precursors, and neurite outgrowth. However, only a few of these subtypes (P2X2, P2X3, P2X4, P2X7, P2Y1, and P2Y2) have been investigated in the context of neurodevelopmental psychiatric disorders. The activation of these potential target receptors and their underlying mechanisms mainly influence the process of neuroinflammation. In particular, P2 receptor-mediated inflammatory cytokine release has been indicated to contribute to the complex mechanisms of a variety of CNS disorders. The released inflammatory cytokines could be utilized as biomarkers for neurodevelopmental and psychiatric disorders to improve the early diagnosis intervention, and prognosis. The population changes in gut microbiota after birth are closely linked to neurodevelopmental/neuropsychiatric disorders in later life; thus, the dynamic expression and function of P2 receptors on gut epithelial cells during disease processes indicate a novel avenue for the evaluation of disease progression and for the discovery of related therapeutic compounds.
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Affiliation(s)
- Lumei Huang
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; János Szentágothai School of Neurosciences, Semmelweis University School of PhD Studies, Budapest, Hungary
| | - Lilla Otrokocsi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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34
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Singhrao SK, Olsen I. Assessing the role of Porphyromonas gingivalis in periodontitis to determine a causative relationship with Alzheimer's disease. J Oral Microbiol 2019; 11:1563405. [PMID: 30728914 PMCID: PMC6352933 DOI: 10.1080/20002297.2018.1563405] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 01/14/2023] Open
Abstract
Chronic periodontitis of 10 years' duration is reported to become a twofold risk factor for the development of Alzheimer's disease (AD). Periodontitis is modifiable, and this fits with the current action plan for preventing AD. However, until periodontitis, becomes acknowledged as a firm risk factor for AD, this risk will continue. Here, we put forward our own argument based on the current literature for in vivo infection-mediated periodontal disease models supporting the antimicrobial protection hypothesis of AD and interventional studies supporting the causal links. Oral infections with Porphyromonas gingivalis, or introduction of its lipopolysaccharide (LPS), in various mouse models has demonstrated the development of key neuropathological hallmark lesions defining AD. These are extracellular amyloid-beta plaques, phosphorylated tau, neurofibrillary tangles, widespread acute and chronic inflammation, blood-brain barrier defects together with the clinical phenotype showing impaired learning and spatial memory. Live P. gingivalis and its LPS (commercial or from 'microbullets') are powerful peripheral and intracerebral inflammatory signalling initiators, and this has direct implications on memory and lesion development. Maintaining a healthy oral microbiome and managing periodontal disease with regular surveillance and good oral hygiene throughout life is likely to reduce the unnecessary burden of AD in some individuals.
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Affiliation(s)
- Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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35
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Calovi S, Mut-Arbona P, Sperlágh B. Microglia and the Purinergic Signaling System. Neuroscience 2018; 405:137-147. [PMID: 30582977 DOI: 10.1016/j.neuroscience.2018.12.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 02/07/2023]
Abstract
Microglia are the main resident immune-competent cell type of the central nervous system (CNS); these cells are highly sensitive to subtle changes in the chemical environment of the brain. Microglia are activated during diverse conditions, such as apoptosis, trauma, inflammation, and infection. The specific activities of microglia result from the confluence of environmental stimuli and the cellular state. It is likely that several signaling systems with different biological functions operate in competition and/or synergy, thus regulating similar microglial behaviors. The purinergic system is one of the fundamental signaling systems that establish microglial behavior in a wide spectrum of conditions. Adenosine tri-phosphate (ATP) belongs to the purinergic signaling system, which includes P2X, P2Y, and P1 receptors, as well as other proteins participating in ATP secretion and extracellular ATP degradation, and molecules that recognize purines as a ligand. In this review, we focus on the latest pre-clinical and basic purinergic system and microglial research, with particular attention to data collected in vivo and ex vivo. This chapter is divided into sections related to microglial ATP release, ATP degradation, and ATP-related actions mediated by P2X and P2Y receptor activation.
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Affiliation(s)
- Stefano Calovi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; János Szentágothai School of Neurosciences, Semmelweis University School of PhD Studies, Budapest, Hungary
| | - Paula Mut-Arbona
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; János Szentágothai School of Neurosciences, Semmelweis University School of PhD Studies, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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Singhrao SK, Olsen I. Are Porphyromonas gingivalis Outer Membrane Vesicles Microbullets for Sporadic Alzheimer's Disease Manifestation? J Alzheimers Dis Rep 2018; 2:219-228. [PMID: 30599043 PMCID: PMC6311351 DOI: 10.3233/adr-180080] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our research into Alzheimer's disease (AD) focuses on the oral cavity and the brain, from which key evaluations of prospective and retrospective population-based data have shown that chronic periodontal disease existing for ten-years or over doubles the risk for the sporadic form of AD. Furthermore, Porphyromonas gingivalis (P. gingivalis) mono-infections in established periodontal lesions, or introducing its lipopolysachharide (LPS), as demonstrated in in vivo studies, show hallmark pathology inclusive of extracellular amyloid plaques and phospho-tau bound neurofibrillary tangles with AD-like phenotype. Other studies have shown that if periodontitis remains untreated in human AD patients, cognitive decline ensues. This is a bi-directional relationship meaning that the converse is also true; treating periodontal disease in AD patients improves memory. Bacterial cultures and established oral biofilms generate vast numbers of microvesicles and P. gingivalis outer membrane vesicles encase key virulence factors (LPS, gingipains, capsule, fimbriae) as though they are complete destructive "microbullets" when shed in the host. This provides P. gingivalis additional arsenal to manipulate its entry into disparate organs, hijack phagocytosis, destroy tissues, and affect complement related genes while transducing the onset of proinflammatory signaling cascades. The resulting inflammatory mediators may be the cause of disease defining lesions and cognitive decline typical of clinical AD.
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Affiliation(s)
- Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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3DMorph Automatic Analysis of Microglial Morphology in Three Dimensions from Ex Vivo and In Vivo Imaging. eNeuro 2018; 5:eN-MNT-0266-18. [PMID: 30627639 PMCID: PMC6325541 DOI: 10.1523/eneuro.0266-18.2018] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/18/2018] [Accepted: 10/28/2018] [Indexed: 11/21/2022] Open
Abstract
Microglia are dynamic immune cells of the central nervous system, and their morphology is commonly used as a readout of cellular function. However, current morphological analysis techniques rely on either tracing of cells or two-dimensional projection analysis, which are time-consuming, subject to bias, and may ignore important three-dimensional (3D) information. Therefore, we have created 3DMorph, a MATLAB-based script that analyzes microglial morphology from 3D data. The program initially requires input of threshold levels, cell size expectations, and preferred methods of skeletonization. This makes 3DMorph easily scalable and adaptable to different imaging parameters or cell types. After these settings are defined, the program is completely automatic and can batch process files without user input. Output data includes cell volume, territorial volume, branch length, number of endpoints and branch points, and average distance between cells. We show that 3DMorph is accurate compared to manual tracing, with significantly decreased user input time. Importantly, 3DMorph is capable of processing in vivo microglial morphology, as well as other 3D branching cell types, from mouse cranial windows or acute hippocampal slices. Therefore, we present a novel, user-friendly, scalable, and semiautomatic method of analyzing cell morphology in 3 dimensions. This method should improve the accuracy of cell measurements, remove user bias between conditions, increase reproducibility between experimenters and labs, and reduce user input time. We provide this open source code on GitHub so that it is free and accessible to all investigators.
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38
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Huang D, Yang J, Liu X, He L, Luo X, Tian H, Xu T, Zeng J. P2Y 6 receptor activation is involved in the development of neuropathic pain induced by chronic constriction injury of the sciatic nerve in rats. J Clin Neurosci 2018; 56:156-162. [PMID: 30045810 DOI: 10.1016/j.jocn.2018.07.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/29/2018] [Accepted: 07/08/2018] [Indexed: 12/22/2022]
Abstract
Purinergic signaling in spinal cord microglia plays an important role in the pathogenesis of neuropathic pain. Among all P2 receptors, P2Y6 receptor is expressed in rat dorsal spinal cord. However, it's not clear that the role of P2Y6 receptor in the chronic constriction injury (CCI) model of neuropathic pain rats. We evaluated the effect of repeated intrathecal administration of MRS2578 (selective P2Y6 receptor antagonist) on CCI-induced nociceptive behaviors in rats. After CCI, MRS2578 (10-11-10-4 M) was administration. The thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were assessed. The expression of P2Y6 receptor and Iba-1 at rat dorsal spinal cord was observed by using RT-PCR. We found that intrathecal injection of MRS2578 suppressed CCI-induced mechanical allodynia and thermal hyperalgesia with a dose-dependent manner. The CCI rats presented increased expression of P2Y6 receptor and Iba-1 at the mRNA level in the ipsilateral dorsal spinal cord than that in sham group. Treatment with either minocycline or SB203580 effectively inhibited P2Y6 receptor expression compared to CCI rats. Intrathecal injection of UDP enhanced mechanical and thermal allodynia than that in CCI group. To the further study, intrathecal injection of UDP causes mechanical allodynia and thermal hyperalgesia in naive rats. The increased expression of P2Y6 receptor and Iba-1 were observed in UDP-treated rats. Intrathecal injection of MRS2578 alleviates pain response in UDP-treated rats. These observations suggested that P2Y6 receptor in dorsal spinal cord contribute to mechanical allodynia and thermal hyperalgesia in CCI-induced neuropathic pain.
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Affiliation(s)
- Dujuan Huang
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Junna Yang
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - XiaoHong Liu
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Li He
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Xiaomei Luo
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Hong Tian
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Tao Xu
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China
| | - Junwei Zeng
- Department of Physiology, Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou Province 563000, China.
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Harding A, Robinson S, Crean S, Singhrao SK. Can Better Management of Periodontal Disease Delay the Onset and Progression of Alzheimer's Disease? J Alzheimers Dis 2018; 58:337-348. [PMID: 28453484 DOI: 10.3233/jad-170046] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A risk factor relationship exists between periodontal disease and Alzheimer's disease (AD) via tooth loss, and improved memory following dental intervention. This links the microbial contribution from indigenous oral periodontal pathogens to the manifestation of chronic conditions, such as AD. Here, we use Porphyromonas gingivalis infection to illustrate its effect on mental health. P. gingivalis infection, in its primary sub-gingival niche, can cause polymicrobial synergy and dysbiosis. Dysbiosis describes the residency of select commensals from the oral cavity following co-aggregation around the dominant keystone pathogen, such as P. gingivalis, to gain greater virulence. The initial process involves P. gingivalis disturbing neutrophil mediated innate immune responses in the healthy gingivae and then downregulating adaptive immune cell differentiation and development to invade, and subsequently, establish new dysbiotic bacterial communities. Immune responses affect the host in general and functionally via dietary adjustments caused by tooth loss. Studies from animals orally infected with P. gingivalis confirm this bacterium can transmigrate to distant organ sites (the brain) and contribute toward peripheral and intracerebral inflammation, and compromise vascular and microvascular integrity. In another study, P. gingivalis infection caused sleep pattern disturbances by altering glial cell light/dark molecular clock activity, and this, in turn, can affect the clearance of danger associated molecular patterns, such as amyloid-β, via the glymphatic system. Since P. gingivalis can transmigrate to the brain and modulate organ-specific inflammatory innate and adaptive immune responses, this paper explores whether better management of indigenous periodontal bacteria could delay/prevent the onset and/or progression of dementia.
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Harding A, Gonder U, Robinson SJ, Crean S, Singhrao SK. Exploring the Association between Alzheimer's Disease, Oral Health, Microbial Endocrinology and Nutrition. Front Aging Neurosci 2017; 9:398. [PMID: 29249963 PMCID: PMC5717030 DOI: 10.3389/fnagi.2017.00398] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/17/2017] [Indexed: 12/21/2022] Open
Abstract
Longitudinal monitoring of patients suggests a causal link between chronic periodontitis and the development of Alzheimer’s disease (AD). However, the explanation of how periodontitis can lead to dementia remains unclear. A working hypothesis links extrinsic inflammation as a secondary cause of AD. This hypothesis suggests a compromised oral hygiene leads to a dysbiotic oral microbiome whereby Porphyromonas gingivalis, a keystone periodontal pathogen, with its companion species, orchestrates immune subversion in the host. Brushing and chewing on teeth supported by already injured soft tissues leads to bacteremias. As a result, a persistent systemic inflammatory response develops to periodontal pathogens. The pathogens, and the host’s inflammatory response, subsequently lead to the initiation and progression of multiple metabolic and inflammatory co-morbidities, including AD. Insufficient levels of essential micronutrients can lead to microbial dysbiosis through the growth of periodontal pathogens such as demonstrated for P. gingivalis under low hemin bioavailability. An individual’s diet also defines the consortium of microbial communities that take up residency in the oral and gastrointestinal (GI) tract microbiomes. Their imbalance can lead to behavioral changes. For example, probiotics enriched in Lactobacillus genus of bacteria, when ingested, exert some anti-inflammatory influence through common host/bacterial neurochemicals, both locally, and through sensory signaling back to the brain. Early life dietary behaviors may cause an imbalance in the host/microbial endocrinology through a dietary intake incompatible with a healthy GI tract microbiome later in life. This imbalance in host/microbial endocrinology may have a lasting impact on mental health. This observation opens up an opportunity to explore the mechanisms, which may underlie the previously detected relationship between diet, oral/GI microbial communities, to anxiety, cognition and sleep patterns. This review suggests healthy diet based interventions that together with improved life style/behavioral changes may reduce and/or delay the incidence of AD.
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Affiliation(s)
- Alice Harding
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
| | - Ulrike Gonder
- Nutritionist, Freelance Science Writer, Hünstetten, Germany
| | - Sarita J Robinson
- Faculty of Science and Technology, School of Psychology, University of Central Lancashire, Preston, United Kingdom
| | - StJohn Crean
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
| | - Sim K Singhrao
- Dementia & Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, United Kingdom
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41
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Liu Y, Wu Z, Nakanishi Y, Ni J, Hayashi Y, Takayama F, Zhou Y, Kadowaki T, Nakanishi H. Infection of microglia with Porphyromonas gingivalis promotes cell migration and an inflammatory response through the gingipain-mediated activation of protease-activated receptor-2 in mice. Sci Rep 2017; 7:11759. [PMID: 28924232 PMCID: PMC5603557 DOI: 10.1038/s41598-017-12173-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 09/05/2017] [Indexed: 12/14/2022] Open
Abstract
Despite a clear correlation between periodontitis and cognitive decline in Alzheimer's disease, the precise mechanism underlying the relationship remains unclear. The periodontal pathogen Porphyromonas gingivalis produces a unique class of cysteine proteinases termed gingipains that comprises Arg-gingipain (Rgp) and Lys-gingipain (Kgp). Rgp and Kgp are important in the bacterial mediated host cell responses and the subsequent intracellular signaling in infected cells. In the present study, we attempted to clarify the potential effects of Rgp and Kgp on the cellular activation of brain-resident microglia. We provide the first evidence that Rgp and Kgp cooperatively contribute to the P. gingivalis-induced cell migration and expression of proinflammatory mediators through the activation of protease-activated receptor 2. The subsequent activation of phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase/ERK pathways contributes to cell migration and inflammatory response of microglia.
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Affiliation(s)
- Yicong Liu
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Zhou Wu
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan.,OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yurika Nakanishi
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Junjun Ni
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yoshinori Hayashi
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Fumiko Takayama
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yanmin Zhou
- Department of Implantology, School of Stomatology, Jilin University, Changchun, 130021, China
| | - Tomoko Kadowaki
- Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8588, Japan
| | - Hiroshi Nakanishi
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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