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Zhang Y, Guo X, Zhao J, Gao X, Zhang L, Huang T, Wang Y, Niu Q, Zhang Q. The downregulation of TREM2 exacerbates toxicity of development and neurobehavior induced by aluminum chloride and nano-alumina in adult zebrafish. Toxicol Appl Pharmacol 2024; 492:117107. [PMID: 39288838 DOI: 10.1016/j.taap.2024.117107] [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: 05/31/2024] [Revised: 09/13/2024] [Accepted: 09/13/2024] [Indexed: 09/19/2024]
Abstract
To investigate the difference in the development and neurobehavior between aluminum chloride (AlCl3) and nano-alumina (AlNPs) in adult zebrafish and the role of triggering receptor expressed on myeloid cells (TREM2) in this process. Zebrafish embryos were randomly administered with control, negative control, TREM2 knockdown, AlCl3, TREM2 knockdown + AlCl3, AlNPs, and TREM2 knockdown + AlNPs, wherein AlCl3 and AlNPs were 50 mg/L and TREM2 knockdown was achieved by microinjecting lentiviral-containing TREM2 inhibitors into the yolk sac. We assessed development, neurobehavior, histopathology, ultrastructural structure, neurotransmitters (AChE, DA), SOD, genes of TREM2 and neurodevelopment (α1-tubulin, syn2a, mbp), and AD-related proteins and genes. AlCl3 significantly lowered the malformation rate than AlNPs, and further increased rates of malformation and mortality following TREM2 knockdown. The locomotor ability, learning and memory were similar between AlCl3 and AlNPs. TREM2 deficiency further exacerbated their impairment in panic reflex, microglia decrease, and nerve fibers thickening and tangling. AlCl3, rather than AlNPs, significantly elevated AChE activity and p-tau content while decreasing TREM2 and syn2a levels than the control. TREM2 loss further aggravated impairment in the AChE and SOD activity, and psen1 and p-tau levels. Therefore, AlCl3 induces greater developmental toxicity but equivalent neurobehavior toxicity than AlNPs, while their toxicity was intensified by TREM2 deficiency.
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Affiliation(s)
- Ying Zhang
- Department of Toxicology, Shanxi Provincial Center for Disease Control and Prevention, Taiyuan 030012, China
| | - Xinyue Guo
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China; Department of Business Management, Shaanxi Provincial Center for Disease Control and Prevention, Xi'an 710054, China
| | - Jinjin Zhao
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Xiaocheng Gao
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Lan Zhang
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Tao Huang
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Yanhong Wang
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Qiao Niu
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China
| | - Qinli Zhang
- Department of Occupational Medicine, School of public health, Shanxi Medical University, Taiyuan 030001, China; Department of Pathology, University of Mississippi Medical Center, 2500 N State St., Jackson, MS 39216, United States of America.
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Matteoli M. The role of microglial TREM2 in development: A path toward neurodegeneration? Glia 2024; 72:1544-1554. [PMID: 38837837 DOI: 10.1002/glia.24574] [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: 01/20/2024] [Revised: 05/11/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024]
Abstract
The nervous and the immune systems undergo a continuous cross talk, starting from early development and continuing throughout adulthood and aging. Defects in this cross talk contribute to neurodevelopmental and neurodegenerative diseases. Microglia are the resident immune cells in the brain that are primarily involved in this bidirectional communication. Among the microglial genes, trem2 is a key player, controlling the functional state of microglia and being at the forefront of many processes that require interaction between microglia and other brain components, such as neurons and oligodendrocytes. The present review focuses on the early developmental window, describing the early brain processes in which TREM2 is primarily involved, including the modulation of synapse formation and elimination, the control of neuronal bioenergetic states as well as the contribution to myelination processes and neuronal circuit formation. By causing imbalances during these early maturation phases, dysfunctional TREM2 may have a striking impact on the adult brain, making it a more sensitive target for insults occurring during adulthood and aging.
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Affiliation(s)
- Michela Matteoli
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Neuro Center, IRCCS Humanitas Research Hospital, Milan, Italy
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3
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Yin Y, Yang H, Li R, Wu G, Qin Q, Tang Y. A systematic review of the role of TREM2 in Alzheimer's disease. Chin Med J (Engl) 2024; 137:1684-1694. [PMID: 38915213 PMCID: PMC11268819 DOI: 10.1097/cm9.0000000000003000] [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: 12/30/2023] [Indexed: 06/26/2024] Open
Abstract
BACKGROUND Given the established genetic linkage between triggering receptors expressed on myeloid cells 2 (TREM2) and Alzheimer's disease (AD), an expanding research body has delved into the intricate role of TREM2 within the AD context. However, a conflicting landscape of outcomes has emerged from both in vivo and in vitro investigations. This study aimed to elucidate the multifaceted nuances and gain a clearer comprehension of the role of TREM2. METHODS PubMed database was searched spanning from its inception to January 2022. The search criteria took the form of ("Alzheimer's disease" OR "AD") AND ("transgenic mice model" OR "transgenic mouse model") AND ("Triggering receptor expressed on myeloid cells" OR "TREM2"). Inclusion criteria consisted of the following: (1) publication of original studies in English; (2) utilization of transgenic mouse models for AD research; and (3) reports addressing the subject of TREM2. RESULTS A total of 43 eligible articles were identified. Our analysis addresses four pivotal queries concerning the interrelation of TREM2 with microglial function, Aβ accumulation, tau pathology, and inflammatory processes. However, the diverse inquiries posed yielded inconsistent responses. Nevertheless, the inconsistent roles of TREM2 within these AD mouse models potentially hinge upon factors such as age, sex, brain region, model type, and detection methodologies. CONCLUSIONS This review substantiates the evolving understanding of TREM2's disease progression-dependent impacts. Furthermore, it reviews the interplay between TREM2 and its effects across diverse tissues and temporal stages.
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Affiliation(s)
- Yunsi Yin
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Hanchen Yang
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Ruiyang Li
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Guangshan Wu
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Qi Qin
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Yi Tang
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
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Jay TR, Kang Y, Ouellet-Massicotte V, Micael MKB, Kacouros-Perkins VL, Chen J, Sheehan A, Freeman MR. Developmental and age-related synapse elimination is mediated by glial Croquemort. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600214. [PMID: 39026803 PMCID: PMC11257470 DOI: 10.1101/2024.06.24.600214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Neurons and glia work together to dynamically regulate neural circuit assembly and maintenance. In this study, we show Drosophila exhibit large-scale synapse formation and elimination as part of normal CNS circuit maturation, and that glia use conserved molecules to regulate these processes. Using a high throughput ELISA-based in vivo screening assay, we identify new glial genes that regulate synapse numbers in Drosophila in vivo, including the scavenger receptor ortholog Croquemort (Crq). Crq acts as an essential regulator of glial-dependent synapse elimination during development, with glial Crq loss leading to excess CNS synapses and progressive seizure susceptibility in adults. Loss of Crq in glia also prevents age-related synaptic loss in the adult brain. This work provides new insights into the cellular and molecular mechanisms that underlie synapse development and maintenance across the lifespan, and identifies glial Crq as a key regulator of these processes.
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Brennan FH, Swarts EA, Kigerl KA, Mifflin KA, Guan Z, Noble BT, Wang Y, Witcher KG, Godbout JP, Popovich PG. Microglia promote maladaptive plasticity in autonomic circuitry after spinal cord injury in mice. Sci Transl Med 2024; 16:eadi3259. [PMID: 38865485 DOI: 10.1126/scitranslmed.adi3259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 05/16/2024] [Indexed: 06/14/2024]
Abstract
Robust structural remodeling and synaptic plasticity occurs within spinal autonomic circuitry after severe high-level spinal cord injury (SCI). As a result, normally innocuous visceral or somatic stimuli elicit uncontrolled activation of spinal sympathetic reflexes that contribute to systemic disease and organ-specific pathology. How hyperexcitable sympathetic circuitry forms is unknown, but local cues from neighboring glia likely help mold these maladaptive neuronal networks. Here, we used a mouse model of SCI to show that microglia surrounded active glutamatergic interneurons and subsequently coordinated multi-segmental excitatory synaptogenesis and expansion of sympathetic networks that control immune, neuroendocrine, and cardiovascular functions. Depleting microglia during critical periods of circuit remodeling after SCI prevented maladaptive synaptic and structural plasticity in autonomic networks, decreased the frequency and severity of autonomic dysreflexia, and prevented SCI-induced immunosuppression. Forced turnover of microglia in microglia-depleted mice restored structural and functional indices of pathological dysautonomia, providing further evidence that microglia are key effectors of autonomic plasticity. Additional data show that microglia-dependent autonomic plasticity required expression of triggering receptor expressed on myeloid cells 2 (Trem2) and α2δ-1-dependent synaptogenesis. These data suggest that microglia are primary effectors of autonomic neuroplasticity and dysautonomia after SCI in mice. Manipulating microglia may be a strategy to limit autonomic complications after SCI or other forms of neurologic disease.
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Affiliation(s)
- Faith H Brennan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Department of Biomedical and Molecular Sciences and Center for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emily A Swarts
- Department of Biomedical and Molecular Sciences and Center for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Kristina A Kigerl
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Katherine A Mifflin
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Zhen Guan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Benjamin T Noble
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Yan Wang
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Kristina G Witcher
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Jonathan P Godbout
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Phillip G Popovich
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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Lin C, Kong Y, Chen Q, Zeng J, Pan X, Miao J. Decoding sTREM2: its impact on Alzheimer's disease - a comprehensive review of mechanisms and implications. Front Aging Neurosci 2024; 16:1420731. [PMID: 38912524 PMCID: PMC11190086 DOI: 10.3389/fnagi.2024.1420731] [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: 04/21/2024] [Accepted: 05/30/2024] [Indexed: 06/25/2024] Open
Abstract
Soluble Triggering Receptor Expressed on Myeloid Cells 2 (sTREM2) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). This review comprehensively examines sTREM2's involvement in AD, focusing on its regulatory functions in microglial responses, neuroinflammation, and interactions with key pathological processes. We discuss the dynamic changes in sTREM2 levels in cerebrospinal fluid and plasma throughout AD progression, highlighting its potential as a therapeutic target. Furthermore, we explore the impact of genetic variants on sTREM2 expression and its interplay with other AD risk genes. The evidence presented in this review suggests that modulating sTREM2 activity could influence AD trajectory, making it a promising avenue for future research and drug development. By providing a holistic understanding of sTREM2's multifaceted role in AD, this review aims to guide future studies and inspire novel therapeutic strategies.
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Affiliation(s)
- Cui Lin
- Shenzhen Bao’an District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, China
| | - Yu Kong
- Shenzhen Bao’an District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, China
| | - Qian Chen
- Shenzhen Bao’an District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, China
| | - Jixiang Zeng
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, Guangdong, China
| | - Xiaojin Pan
- Shenzhen Bao’an District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, China
| | - Jifei Miao
- Shenzhen Bao’an District Hospital of Traditional Chinese Medicine, Shenzhen, Guangdong, China
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Sharafeddin F, Sierra J, Ghaly M, Simon TB, Ontiveros‐Ángel P, Edelbach B, Febo M, Labus J, Figueroa JD. Role of the prefrontal cortical protease TACE/ADAM17 in neurobehavioral responses to chronic stress during adolescence. Brain Behav 2024; 14:e3482. [PMID: 38715397 PMCID: PMC11077197 DOI: 10.1002/brb3.3482] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/17/2024] [Accepted: 03/20/2024] [Indexed: 05/12/2024] Open
Abstract
INTRODUCTION Chronic adolescent stress profoundly affects prefrontal cortical networks regulating top-down behavior control. However, the neurobiological pathways contributing to stress-induced alterations in the brain and behavior remain largely unknown. Chronic stress influences brain growth factors and immune responses, which may, in turn, disrupt the maturation and function of prefrontal cortical networks. The tumor necrosis factor alpha-converting enzyme/a disintegrin and metalloproteinase 17 (TACE/ADAM17) is a sheddase with essential functions in brain maturation, behavior, and inflammatory responses. This study aimed to determine the impact of stress on the prefrontal cortex and whether TACE/ADAM17 plays a role in these responses. METHODS We used a Lewis rat model that incorporates critical elements of chronic psychosocial stress, such as uncontrollability, unpredictability, lack of social support, and re-experiencing of trauma. RESULTS Chronic stress during adolescence reduced the acoustic startle reflex and social interactions while increasing extracellular free water content and TACE/ADAM17 mRNA levels in the medial prefrontal cortex. Chronic stress altered various ethological behavioral domains in the observation home cages (decreased ingestive behaviors and increased walking, grooming, and rearing behaviors). A group of rats was injected intracerebrally either with a novel Accell™ SMARTpool TACE/ADAM17 siRNA or a corresponding siRNA vehicle (control). The RNAscope Multiplex Fluorescent v2 Assay was used to visualize mRNA expression. Automated puncta quantification and analyses demonstrated that TACE/ADAM17 siRNA administration reduced TACE/ADAM17 mRNA levels in the medial prefrontal cortex (59% reduction relative to control). We found that the rats that received prefrontal cortical TACE/ADAM17 siRNA administration exhibited altered eating patterns (e.g., increased food intake and time in the feeding zone during the light cycle). CONCLUSION This study supports that the prefrontal cortex is sensitive to adolescent chronic stress and suggests that TACE/ADAM17 may be involved in the brain responses to stress.
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Affiliation(s)
- Fransua Sharafeddin
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
| | - Julio Sierra
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
| | - Mina Ghaly
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
| | - Timothy B. Simon
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
| | - Perla Ontiveros‐Ángel
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
| | - Brandon Edelbach
- Department of NeurosurgeryLoma Linda University School of Medicine Loma LindaCAUSA
| | - Marcelo Febo
- Translational Research Imaging Laboratory, Department of Psychiatry, Department of Neuroscience, College of MedicineUniversity of Florida HealthGainesvilleFloridaUSA
| | - Jennifer Labus
- Graduate Program in Bioscience, Division of Digestive Diseases, David Geffen School of MedicineUniversity of CaliforniaLos AngelesUSA
| | - Johnny D. Figueroa
- Center for Health Disparities and Molecular MedicineLoma Linda University School of MedicineLoma LindaCaliforniaUSA
- Department of Basic SciencesLoma Linda University School of MedicineLoma LindaCaliforniaUSA
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Arsenault R, Marshall S, Salois P, Li Q, Zhang W. sTREM2 Differentially Affects Cytokine Expression in Myeloid-Derived Cell Models via MAPK-JNK Signaling Pathway. BIOLOGY 2024; 13:87. [PMID: 38392305 PMCID: PMC10886855 DOI: 10.3390/biology13020087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/15/2024] [Accepted: 01/27/2024] [Indexed: 02/24/2024]
Abstract
TREM2 is a critical innate immune receptor primarily expressed on myeloid-derived cells, such as microglia and macrophages. Mutations in TREM2 are linked to several neurodegenerative diseases including Alzheimer's disease (AD). TREM2 can be cleaved from the cell membrane and released as soluble TREM2 (sTREM2). sTREM2 levels are shown to peak prior to AD, with its levels fluctuating throughout disease progression. However, the mechanism by which sTREM2 may affect innate immune responses is largely uncharacterized. In this study, we investigated whether sTREM2 can induce inflammatory response in myeloid-derived THP-1 monocytes and macrophages and characterized the signaling mechanisms involved. Our results show that sTREM2 was capable of stimulating the expression of several inflammatory cytokines in THP-1 cells throughout the time course of 2 h to 8 h but inducing anti-inflammatory cytokine expression at later time points. A TREM2 antibody was capable of inhibiting the expression of some cytokines induced by sTREM2 but enhancing others. The complex of sTREM2/TREM2 antibody was shown to enhance IL-1β expression, which was partially blocked by an NLRP3 specific inhibitor, indicating that the complex activated the NRLP3 inflammasome pathway. sTREM2 was also shown to have differential effects on cytokine expression in M0, M1, and M2 macrophages differentiated from THP-1 cells. sTREM2 has a more stimulating effect on cytokine expression in M0 macrophages, less of an effect on M2 macrophages, and some inhibitory effects on cytokine expression in M1 macrophages at early time points. Analyses of several signaling pathways revealed that sTREM2-induced expression of cytokines occurs mainly through MAPK-JNK signaling. Our work reveals differential effects of sTREM2 on cytokine expression profiles of THP-1 cells and macrophages and demonstrates that the MAPK-JNK signaling pathway is mainly responsible for sTREM2-induced cytokine expression.
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Affiliation(s)
- Ryan Arsenault
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Steven Marshall
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Patrick Salois
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
| | - Qiao Li
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Wandong Zhang
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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9
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Meng J, Han L, Xu H, Zhang L, Liu Z, Zhou Y, Zhang X, Luo H, Zhang YW. TREM2 regulates microglial phagocytosis of synapses in innate immune tolerance. Int Immunopharmacol 2024; 127:111445. [PMID: 38147777 DOI: 10.1016/j.intimp.2023.111445] [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: 11/08/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 12/28/2023]
Abstract
Increasing evidence indicates that innate immune cells also possess immunological memory. Microglia are brain-resident innate immune cells and execute inflammatory and phagocytic functions upon environmental stimulation, during which processes triggering receptor expressed on myeloid cells 2 (TREM2) plays an important regulatory role. However, although microglia are known to exhibit innate immune memory related to inflammation when subjected to continuous inflammatory stimuli, whether microglia exhibit innate immune memory related to phagocytosis and whether TREM2 participates in innate immune memory of microglia remain unknown. Herein, we treated WT and Trem2 KO mice with peripheral injection of lipopolysaccharides (LPS) to induce microglial activation or microglial immune tolerance. We found that Tnfα and Il-1β expression levels in the hippocampi were significantly elevated after 1xLPS and then dramatically decreased after 4xLPS in both WT and Trem2 KO mice; and their level changes were indistinguishable between WT and Trem2 KO mice. Moreover, 1xLPS significantly promoted microglial phagocytosis of synapses and caused microglial morphology changes resembling activated status in both WT and Trem2 KO mice. However, 4xLPS significantly reduced synapse phagocytosis and largely reversed morphology changes in WT microglia. While 4xLPS had no effect on reducing synapse phagocytosis in Trem2 KO microglia. RNA-seq analysis revealed that TREM2 deficiency reprogrammed complement and phagosome-related transcriptional landscape during immune tolerance. Our results demonstrate that microglia also exhibit immune tolerance related to phagocytosis of synapses and that TREM2 plays a crucial role in this process possibly through regulating complement system and phagosome-related gene expressions.
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Affiliation(s)
- Jian Meng
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
| | - Linkun Han
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Hui Xu
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Lingliang Zhang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhaoji Liu
- Department of Neurology, Zhongshan Hospital Xiamen University, Xiamen, Fujian 361004, China
| | - Yunqiang Zhou
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Xian Zhang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Hong Luo
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Yun-Wu Zhang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
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Xiong Y, Cui MY, Li ZL, Fu YQ, Zheng Y, Yu Y, Zhang C, Huang XY, Chen BH. ULK1 confers neuroprotection by regulating microglial/macrophages activation after ischemic stroke. Int Immunopharmacol 2024; 127:111379. [PMID: 38141409 DOI: 10.1016/j.intimp.2023.111379] [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: 09/29/2023] [Revised: 11/28/2023] [Accepted: 12/11/2023] [Indexed: 12/25/2023]
Abstract
Microglial activation and autophagy play a critical role in the progression of ischemic stroke and contribute to the regulation of neuroinflammation. Unc-51-like kinase 1 (ULK1) is the primary autophagy kinase involved in autophagosome formation. However, the impact of ULK1 on neuroprotection and microglial activation after ischemic stroke remains unclear. In this study, we established a photothrombotic stroke model, and administered SBI-0206965 (SBI), an ULK1 inhibitor, and LYN-1604 hydrochloride (LYN), an ULK1 agonist, to modulate ULK1 activity in vivo. We assessed sensorimotor deficits, neuronal apoptosis, and microglial/macrophage activation to evaluate the neurofunctional outcome. Immunofluorescence results revealed ULK1 was primarily localized in the microglia of the infarct area following ischemia. Upregulating ULK1 through LYN treatment significantly reduced infarct volume, improved motor function, promoted the increase of anti-inflammatory microglia. In conclusion, ULK1 facilitated neuronal repair and promoted the formation of anti-inflammatory microglia pathway after ischemic injury.
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Affiliation(s)
- Ye Xiong
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Mai Yin Cui
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China; Department of Rehabilitation and Traditional Chinese Medicine, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310051, Zhejiang, China
| | - Zhuo Li Li
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Yan Qiong Fu
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Yu Zheng
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Yi Yu
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325000, Zhejiang, China
| | - Chan Zhang
- School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Xin Yi Huang
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Bai Hui Chen
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China.
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11
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Lankhuijzen LM, Ridler T. Opioids, microglia, and temporal lobe epilepsy. Front Neurol 2024; 14:1298489. [PMID: 38249734 PMCID: PMC10796828 DOI: 10.3389/fneur.2023.1298489] [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: 09/21/2023] [Accepted: 12/15/2023] [Indexed: 01/23/2024] Open
Abstract
A lack of treatment options for temporal lobe epilepsy (TLE) demands an urgent quest for new therapies to recover neuronal damage and reduce seizures, potentially interrupting the neurotoxic cascades that fuel hyper-excitability. Endogenous opioids, along with their respective receptors, particularly dynorphin and kappa-opioid-receptor, present as attractive candidates for controlling neuronal excitability and therapeutics in epilepsy. We perform a critical review of the literature to evaluate the role of opioids in modulating microglial function and morphology in epilepsy. We find that, in accordance with anticonvulsant effects, acute opioid receptor activation has unique abilities to modulate microglial activation through toll-like 4 receptors, regulating downstream secretion of cytokines. Abnormal activation of microglia is a dominant feature of neuroinflammation, and inflammatory cytokines are found to aggravate TLE, inspiring the challenge to alter microglial activation by opioids to suppress seizures. We further evaluate how opioids can modulate microglial activation in epilepsy to enhance neuroprotection and reduce seizures. With controlled application, opioids may interrupt inflammatory cycles in epilepsy, to protect neuronal function and reduce seizures. Research on opioid-microglia interactions has important implications for epilepsy and healthcare approaches. However, preclinical research on opioid modulation of microglia supports a new therapeutic pathway for TLE.
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Affiliation(s)
| | - Thomas Ridler
- Hatherly Laboratories, Department of Clinical and Biomedical Sciences, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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12
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Vecchiarelli HA, Lopes LT, Paolicelli RC, Stevens B, Wake H, Tremblay MÈ. Synapse Regulation. ADVANCES IN NEUROBIOLOGY 2024; 37:179-208. [PMID: 39207693 DOI: 10.1007/978-3-031-55529-9_11] [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
Microglia are the resident immune cells of the brain. As such, they rapidly detect changes in normal brain homeostasis and accurately respond by fine-tuning in a tightly regulated manner their morphology, gene expression, and functional behavior. Depending on the nature of these changes, microglia can thicken and retract their processes, proliferate and migrate, release numerous signaling factors and compounds influencing neuronal physiology (e.g., cytokines and trophic factors), in addition to secreting proteases able to transform the extracellular matrix, and phagocytosing various types of cellular debris, etc. Because microglia also transform rapidly (on a time scale of minutes) during experimental procedures, studying these very special cells requires methods that are specifically non-invasive. The development of such methods has provided unprecedented insights into the roles of microglia during normal physiological conditions. In particular, transcranial two-photon in vivo imaging revealed that presumably "resting" microglia continuously survey the brain parenchyma with their highly motile processes, in addition to modulating their structural and functional interactions with neuronal circuits along the changes in neuronal activity and behavioral experience occurring throughout the lifespan. In this chapter, we will describe how surveillant microglia interact with synaptic elements and modulate the number, maturation, function, and plasticity of synapses in the healthy developing, mature, and aging brain, with consequences on neuronal activity, learning and memory, and the behavioral outcome.
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Affiliation(s)
| | | | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zurich, Schlieren, Switzerland
| | - Beth Stevens
- Department of Neurology, Harvard Medical School, Center for Life Science, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, USA
| | - Hiroaki Wake
- Division of Brain Circuits, National Institute for Basic Biology, Myodaiji-cho, Okazaki, Japan
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
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13
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Augusto-Oliveira M, Tremblay MÈ, Verkhratsky A. Receptors on Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:83-121. [PMID: 39207688 DOI: 10.1007/978-3-031-55529-9_6] [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
Microglial cells are the most receptive cells in the central nervous system (CNS), expressing several classes of receptors reflecting their immune heritage and newly acquired neural specialisation. Microglia possess, depending on the particular context, receptors to neurotransmitters and neuromodulators as well as immunocompetent receptors. This rich complement allows microglial cells to monitor the functional status of the nervous system, contribute actively to the regulation of neural activity and plasticity and homeostasis, and guard against pathogens as well as other challenges to the CNS's integrity and function.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
- Programa de Pós-Graduação em Farmacologia e Bioquímica, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, Canada
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, Vancouver, BC, Canada
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK.
- Department of Neurosciences, University of the Basque Country, Leioa, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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14
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Williams KE, Zou Y, Qiu B, Kono T, Guo C, Garcia D, Chen H, Graves T, Lai Z, Evans-Molina C, Ma YY, Liangpunsakul S, Yong W, Liang T. Sex-Specific Impact of Fkbp5 on Hippocampal Response to Acute Alcohol Injection: Involvement in Alterations of Metabolism-Related Pathways. Cells 2023; 13:89. [PMID: 38201293 PMCID: PMC10778370 DOI: 10.3390/cells13010089] [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: 10/30/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
High levels of alcohol intake alter brain gene expression and can produce long-lasting effects. FK506-binding protein 51 (FKBP51) encoded by Fkbp5 is a physical and cellular stress response gene and has been associated with alcohol consumption and withdrawal severity. Fkbp5 has been previously linked to neurite outgrowth and hippocampal morphology, sex differences in stress response, and epigenetic modification. Presently, primary cultured Fkbp5 KO and WT mouse neurons were examined for neurite outgrowth and mitochondrial signal with and without alcohol. We found neurite specification differences between KO and WT; particularly, mesh-like morphology was observed after alcohol treatment and confirmed higher MitoTracker signal in cultured neurons of Fkbp5 KO compared to WT at both naive and alcohol-treated conditions. Brain regions that express FKBP51 protein were identified, and hippocampus was confirmed to possess a high level of expression. RNA-seq profiling was performed using the hippocampus of naïve or alcohol-injected (2 mg EtOH/Kg) male and female Fkbp5 KO and WT mice. Differentially expressed genes (DEGs) were identified between Fkbp5 KO and WT at baseline and following alcohol treatment, with female comparisons possessing a higher number of DEGs than male comparisons. Pathway analysis suggested that genes affecting calcium signaling, lipid metabolism, and axon guidance were differentially expressed at naïve condition between KO and WT. Alcohol treatment significantly affected pathways and enzymes involved in biosynthesis (Keto, serine, and glycine) and signaling (dopamine and insulin receptor), and neuroprotective role. Functions related to cell morphology, cell-to-cell signaling, lipid metabolism, injury response, and post-translational modification were significantly altered due to alcohol. In summary, Fkbp5 plays a critical role in the response to acute alcohol treatment by altering metabolism and signaling-related genes.
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Affiliation(s)
- Kent E. Williams
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University, Indianapolis, IN 46202, USA; (K.E.W.); (T.G.); (S.L.)
| | - Yi Zou
- Greehey Children’s Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (Y.Z.); (D.G.); (Z.L.)
| | - Bin Qiu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA;
| | - Tatsuyoshi Kono
- Diabetes Research Center, Division of Endocrinology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (T.K.); (C.E.-M.)
| | - Changyong Guo
- Department Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (C.G.); (Y.-Y.M.)
| | - Dawn Garcia
- Greehey Children’s Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (Y.Z.); (D.G.); (Z.L.)
| | - Hanying Chen
- Department Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Tamara Graves
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University, Indianapolis, IN 46202, USA; (K.E.W.); (T.G.); (S.L.)
| | - Zhao Lai
- Greehey Children’s Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (Y.Z.); (D.G.); (Z.L.)
| | - Carmella Evans-Molina
- Diabetes Research Center, Division of Endocrinology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (T.K.); (C.E.-M.)
| | - Yao-Ying Ma
- Department Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (C.G.); (Y.-Y.M.)
| | - Suthat Liangpunsakul
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University, Indianapolis, IN 46202, USA; (K.E.W.); (T.G.); (S.L.)
- Roudebush Veterans Administration Medical Center, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Weidong Yong
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Tiebing Liang
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University, Indianapolis, IN 46202, USA; (K.E.W.); (T.G.); (S.L.)
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15
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Matuleviciute R, Akinluyi ET, Muntslag TAO, Dewing JM, Long KR, Vernon AC, Tremblay ME, Menassa DA. Microglial contribution to the pathology of neurodevelopmental disorders in humans. Acta Neuropathol 2023; 146:663-683. [PMID: 37656188 PMCID: PMC10564830 DOI: 10.1007/s00401-023-02629-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/25/2023] [Accepted: 08/26/2023] [Indexed: 09/02/2023]
Abstract
Microglia are the brain's resident macrophages, which guide various developmental processes crucial for brain maturation, activity, and plasticity. Microglial progenitors enter the telencephalic wall by the 4th postconceptional week and colonise the fetal brain in a manner that spatiotemporally tracks key neurodevelopmental processes in humans. However, much of what we know about how microglia shape neurodevelopment comes from rodent studies. Multiple differences exist between human and rodent microglia warranting further focus on the human condition, particularly as microglia are emerging as critically involved in the pathological signature of various cognitive and neurodevelopmental disorders. In this article, we review the evidence supporting microglial involvement in basic neurodevelopmental processes by focusing on the human species. We next concur on the neuropathological evidence demonstrating whether and how microglia contribute to the aetiology of two neurodevelopmental disorders: autism spectrum conditions and schizophrenia. Next, we highlight how recent technologies have revolutionised our understanding of microglial biology with a focus on how these tools can help us elucidate at unprecedented resolution the links between microglia and neurodevelopmental disorders. We conclude by reviewing which current treatment approaches have shown most promise towards targeting microglia in neurodevelopmental disorders and suggest novel avenues for future consideration.
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Affiliation(s)
- Rugile Matuleviciute
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Elizabeth T Akinluyi
- Division of Medical Sciences, University of Victoria, Victoria, Canada
- Department of Pharmacology and Therapeutics, Afe Babalola University, Ado Ekiti, Nigeria
| | - Tim A O Muntslag
- Princess Maxima Centre for Paediatric Oncology, Utrecht, The Netherlands
| | | | - Katherine R Long
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Anthony C Vernon
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | | | - David A Menassa
- Department of Neuropathology & The Queen's College, University of Oxford, Oxford, UK.
- Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
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16
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Prengel TM, Brunne B, Habiballa M, Rune GM. Sexually differentiated microglia and CA1 hippocampal synaptic connectivity. J Neuroendocrinol 2023; 35:e13276. [PMID: 37170708 DOI: 10.1111/jne.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/14/2023] [Accepted: 03/31/2023] [Indexed: 05/13/2023]
Abstract
Microglia have been shown to sculpt postnatal circuitry from birth up to adulthood due to their role in both synapse formation, synaptic pruning, and the elimination of weak, redundant synapses. Microglia are differentiated in a sex-dependent manner. In this study, we tested whether sexual differentiation of microglia results in sex-dependent postnatal reorganization of CA1 synaptic connectivity in the hippocampus. The stereological counting of synapses in mice using electron microscopy showed a continuous rise in synapse density until the fourth week, followed by a plateau phase and loss of synapses from the eighth week onwards, with no difference between sexes. This course of alteration in synapse numbers did not differ between sexes. However, selectively, on postnatal day (P) 14 the density of synapses was significantly higher in the female than in the male hippocampus. Higher synapse density in females was paralleled by higher activity of microglia, as indicated by morphological changes, CD68 expression, and proximity of microglia to synaptic sites. In Thy1-GFP mice, consistent with increased synapse numbers, bouton density was also clearly increased in females at P14. At this time point, CD47 expression, the "don't eat me" signal of neurons, was similar in males and females. The decrease in bouton density thereafter in conjunction with increased synapse numbers argues for a role of microglia in the formation of multispine boutons (MSB). Our data in females at P14 support the regulatory role of microglia in synapse density. Sexual differentiation of microglia, however, does not substantially affect long-term synaptic reorganization in the hippocampus.
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Affiliation(s)
- Tim M Prengel
- Institute of Neuroanatomy, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Bianka Brunne
- Institute of Neuroanatomy, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Moataz Habiballa
- Institute of Neuroanatomy, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Gabriele M Rune
- Institute of Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Berlin, Germany
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17
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Li C, Wang Y, Xing Y, Han J, Zhang Y, Zhang A, Hu J, Hua Y, Bai Y. Regulation of microglia phagocytosis and potential involvement of exercise. Front Cell Neurosci 2022; 16:953534. [PMID: 35959472 PMCID: PMC9357882 DOI: 10.3389/fncel.2022.953534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/29/2022] [Indexed: 12/11/2022] Open
Abstract
Microglia are considered the main phagocytic cells in the central nervous system, remodeling neural circuits by pruning synapses during development. Microglial phagocytosis is also a crucial process in maintaining adult brain homeostasis and clearing potential toxic factors, which are recognized to be associated with neurodegenerative and neuroinflammatory disorders. For example, microglia can engulf amyloid-β plaques, myelin debris, apoptotic cells, and extracellular harmful substances by expressing a variety of specific receptors on the cell surface or by reprogramming intracellular glucose and lipid metabolism processes. Furthermore, physical exercise has been implicated to be one of the non-pharmaceutical treatments for various nervous system diseases, which is closely related to neuroplasticity and microglia functions including proliferation, activation, and phagocytosis. This review focuses on the central regulatory mechanisms related to microglia phagocytosis and the potential role of exercise training in this process.
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Affiliation(s)
- Congqin Li
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yong Wang
- Department of Neurology, Minhang Hospital, Fudan University, Shanghai, China
| | - Ying Xing
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jing Han
- State Key Laboratory of Medical Neurobiology, Department of Integrative Medicine and Neurobiology, Brain Science Collaborative Innovation Center, School of Basic Medical Sciences, Institutes of Brain Science, Fudan Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Yuqian Zhang
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Anjing Zhang
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jian Hu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yan Hua
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yulong Bai
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China
- National Center for Neurological Disorders, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
- *Correspondence: Yulong Bai
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18
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Aberrant Synaptic Pruning in CNS Diseases: A Critical Player in HIV-Associated Neurological Dysfunction? Cells 2022; 11:cells11121943. [PMID: 35741071 PMCID: PMC9222069 DOI: 10.3390/cells11121943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/28/2022] [Accepted: 06/14/2022] [Indexed: 02/04/2023] Open
Abstract
Even in the era of effective antiretroviral therapies, people living with Human Immunodeficiency Virus (HIV) are burdened with debilitating neurological dysfunction, such as HIV-associated neurocognitive disorders (HAND) and HIV-associated pain, for which there are no FDA approved treatments. Disruption to the neural circuits of cognition and pain in the form of synaptic degeneration is implicated in developing these dysfunctions. Glia-mediated synaptic pruning is a mechanism of structural plasticity in the healthy central nervous system (CNS), but recently, it has been discovered that dysregulated glia-mediated synaptic pruning is the cause of synaptic degeneration, leading to maladaptive plasticity and cognitive deficits in multiple diseases of the CNS. Considering the essential contribution of activated glial cells during the development of HAND and HIV-associated pain, it is possible that glia-mediated synaptic pruning is the causative mechanism of synaptic degeneration induced by HIV. This review will analyze the known examples of synaptic pruning during disease in order to better understand how this mechanism could contribute to the progression of HAND and HIV-associated pain.
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19
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Region-Specific Characteristics of Astrocytes and Microglia: A Possible Involvement in Aging and Diseases. Cells 2022; 11:cells11121902. [PMID: 35741031 PMCID: PMC9220858 DOI: 10.3390/cells11121902] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022] Open
Abstract
Although different regions of the brain are dedicated to specific functions, the intra- and inter-regional heterogeneity of astrocytes and microglia in these regions has not yet been fully understood. Recently, an advancement in various technologies, such as single-cell RNA sequencing, has allowed for the discovery of astrocytes and microglia with distinct molecular fingerprints and varying functions in the brain. In addition, the regional heterogeneity of astrocytes and microglia exhibits different functions in several situations, such as aging and neurodegenerative diseases. Therefore, investigating the region-specific astrocytes and microglia is important in understanding the overall function of the brain. In this review, we summarize up-to-date research on various intra- and inter-regional heterogeneities of astrocytes and microglia, and provide information on how they can be applied to aging and neurodegenerative diseases.
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20
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Sanchez-Varo R, Mejias-Ortega M, Fernandez-Valenzuela JJ, Nuñez-Diaz C, Caceres-Palomo L, Vegas-Gomez L, Sanchez-Mejias E, Trujillo-Estrada L, Garcia-Leon JA, Moreno-Gonzalez I, Vizuete M, Vitorica J, Baglietto-Vargas D, Gutierrez A. Transgenic Mouse Models of Alzheimer's Disease: An Integrative Analysis. Int J Mol Sci 2022; 23:5404. [PMID: 35628216 PMCID: PMC9142061 DOI: 10.3390/ijms23105404] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/10/2022] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) constitutes the most prominent form of dementia among elderly individuals worldwide. Disease modeling using murine transgenic mice was first initiated thanks to the discovery of heritable mutations in amyloid precursor protein (APP) and presenilins (PS) genes. However, due to the repeated failure of translational applications from animal models to human patients, along with the recent advances in genetic susceptibility and our current understanding on disease biology, these models have evolved over time in an attempt to better reproduce the complexity of this devastating disease and improve their applicability. In this review, we provide a comprehensive overview about the major pathological elements of human AD (plaques, tauopathy, synaptic damage, neuronal death, neuroinflammation and glial dysfunction), discussing the knowledge that available mouse models have provided about the mechanisms underlying human disease. Moreover, we highlight the pros and cons of current models, and the revolution offered by the concomitant use of transgenic mice and omics technologies that may lead to a more rapid improvement of the present modeling battery.
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Affiliation(s)
- Raquel Sanchez-Varo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
| | - Marina Mejias-Ortega
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Juan Jose Fernandez-Valenzuela
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Cristina Nuñez-Diaz
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Caceres-Palomo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Vegas-Gomez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Elisabeth Sanchez-Mejias
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Trujillo-Estrada
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Juan Antonio Garcia-Leon
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Ines Moreno-Gonzalez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Marisa Vizuete
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocio/CSIC, 41012 Seville, Spain
| | - Javier Vitorica
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocio/CSIC, 41012 Seville, Spain
| | - David Baglietto-Vargas
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Antonia Gutierrez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
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21
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Konishi H, Koizumi S, Kiyama H. Phagocytic astrocytes: Emerging from the shadows of microglia. Glia 2022; 70:1009-1026. [PMID: 35142399 PMCID: PMC9305589 DOI: 10.1002/glia.24145] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/18/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the maintenance of a healthy CNS or for recovery after injury. Live cells or parts thereof, such as the synapses and myelin, are appropriately eliminated by phagocytosis to maintain or refine neural networks during development and adulthood. Microglia, the specific population of resident macrophages in the CNS, are classically considered as primary phagocytes; however, astrocytes have also been highlighted as phagocytes in the last decade. Phagocytic targets and receptors are reported to be mostly common between astrocytes and microglia, which raises the question of how astrocytic phagocytosis differs from microglial phagocytosis, and how these two phagocytic systems cooperate. In this review, we address the consequences of astrocytic phagocytosis, particularly focusing on these elusive points.
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Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
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22
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Sen MK, Mahns DA, Coorssen JR, Shortland PJ. The roles of microglia and astrocytes in phagocytosis and myelination: Insights from the cuprizone model of multiple sclerosis. Glia 2022; 70:1215-1250. [PMID: 35107839 PMCID: PMC9302634 DOI: 10.1002/glia.24148] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/12/2022]
Abstract
In human demyelinating diseases such as multiple sclerosis (MS), an imbalance between demyelination and remyelination can trigger progressive degenerative processes. The clearance of myelin debris (phagocytosis) from the site of demyelination by microglia is critically important to achieve adequate remyelination and to slow the progression of the disease. However, how microglia phagocytose the myelin debris, and why clearance is impaired in MS, is not fully known; likewise, the role of the microglia in remyelination remains unclear. Recent studies using cuprizone (CPZ) as an animal model of central nervous system demyelination revealed that the up‐regulation of signaling proteins in microglia facilitates effective phagocytosis of myelin debris. Moreover, during demyelination, protective mediators are released from activated microglia, resulting in the acceleration of remyelination in the CPZ model. In contrast, inadequate microglial activation or recruitment to the site of demyelination, and the production of toxic mediators, impairs remyelination resulting in progressive demyelination. In addition to the microglia‐mediated phagocytosis, astrocytes play an important role in the phagocytic process by recruiting microglia to the site of demyelination and producing regenerative mediators. The current review is an update of these emerging findings from the CPZ animal model, discussing the roles of microglia and astrocytes in phagocytosis and myelination.
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Affiliation(s)
- Monokesh K Sen
- School of Medicine, Western Sydney University, Penrith, Australia
| | - David A Mahns
- School of Medicine, Western Sydney University, Penrith, Australia
| | - Jens R Coorssen
- Faculty of Applied Health Sciences and Faculty of Mathematics & Science, Brock University, St. Cathari, Canada
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23
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Huang Z, Luo Z, Ovcjak A, Wan J, Chen NH, Hu W, Sun HS, Feng ZP. AD-16 Protects Against Hypoxic-Ischemic Brain Injury by Inhibiting Neuroinflammation. Neurosci Bull 2022; 38:857-870. [PMID: 35072896 PMCID: PMC9352839 DOI: 10.1007/s12264-021-00816-3] [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: 08/10/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022] Open
Abstract
Neuroinflammation is a key contributor to the pathogenic cascades induced by hypoxic-ischemic (HI) insult in the neonatal brain. AD-16 is a novel anti-inflammatory compound, recently found to exert potent inhibition of the lipopolysaccharide-induced production of pro-inflammatory and neurotoxic mediators. In this study, we evaluated the effect of AD-16 on primary astrocytes and neurons under oxygen-glucose deprivation (OGD) in vitro and in mice with neonatal HI brain injury in vivo. We demonstrated that AD-16 protected against OGD-induced astrocytic and neuronal cell injury. Single dose post-treatment with AD-16 (1 mg/kg) improved the neurobehavioral outcome and reduced the infarct volume with a therapeutic window of up to 6 h. Chronic administration reduced the mortality rate and preserved whole-brain morphology following neonatal HI. The in vitro and in vivo effects suggest that AD-16 offers promising therapeutic efficacy in attenuating the progression of HI brain injury and protecting against the associated mortality and morbidity.
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Affiliation(s)
- Zhihua Huang
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Surgery, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Zhengwei Luo
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Surgery, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Andrea Ovcjak
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jiangfan Wan
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Surgery, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Wenhui Hu
- Key Laboratory of Molecular Target and Clinical Pharmacology, State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, Guangdong, China
| | - Hong-Shuo Sun
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Surgery, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada.
| | - Zhong-Ping Feng
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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24
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Faust TE, Gunner G, Schafer DP. Mechanisms governing activity-dependent synaptic pruning in the developing mammalian CNS. Nat Rev Neurosci 2021; 22:657-673. [PMID: 34545240 PMCID: PMC8541743 DOI: 10.1038/s41583-021-00507-y] [Citation(s) in RCA: 152] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 02/08/2023]
Abstract
Almost 60 years have passed since the initial discovery by Hubel and Wiesel that changes in neuronal activity can elicit developmental rewiring of the central nervous system (CNS). Over this period, we have gained a more comprehensive picture of how both spontaneous neural activity and sensory experience-induced changes in neuronal activity guide CNS circuit development. Here we review activity-dependent synaptic pruning in the mammalian CNS, which we define as the removal of a subset of synapses, while others are maintained, in response to changes in neural activity in the developing nervous system. We discuss the mounting evidence that immune and cell-death molecules are important mechanistic links by which changes in neural activity guide the pruning of specific synapses, emphasizing the role of glial cells in this process. Finally, we discuss how these developmental pruning programmes may go awry in neurodevelopmental disorders of the human CNS, focusing on autism spectrum disorder and schizophrenia. Together, our aim is to give an overview of how the field of activity-dependent pruning research has evolved, led to exciting new questions and guided the identification of new, therapeutically relevant mechanisms that result in aberrant circuit development in neurodevelopmental disorders.
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Affiliation(s)
- Travis E Faust
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Georgia Gunner
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dorothy P Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA.
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25
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Dziabis JE, Bilbo SD. Microglia and Sensitive Periods in Brain Development. Curr Top Behav Neurosci 2021; 53:55-78. [PMID: 34463934 DOI: 10.1007/7854_2021_242] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
From embryonic neuronal migration to adolescent circuit refinement, the immune system plays an essential role throughout central nervous system (CNS) development. Immune signaling molecules serve as a common language between the immune system and CNS, allowing them to work together to modulate brain function both in health and disease. As the resident CNS macrophage, microglia comprise the majority of immune cells in the brain. Much like their peripheral counterparts, microglia survey their environment for pathology, clean up debris, and propagate inflammatory responses when necessary. Beyond this, recent studies have highlighted that microglia perform a number of complex tasks during neural development, from directing neuronal and axonal positioning to pruning synapses, receptors, and even whole cells. In this chapter, we discuss this literature within the framework that immune activation during discrete windows of neural development can profoundly impact brain function long-term, and thus the risk of neurodevelopmental and neuropsychiatric disorders. In this chapter, we review three sensitive developmental periods - embryonic wiring, early postnatal synaptic pruning, and adolescent circuit refinement - in order to highlight the diversity of functions that microglia perform in building a brain. In reviewing this literature, it becomes obvious that timing matters, perhaps more so than the nature of the immune activation itself; largely conserved patterns of microglial response to diverse insults result in different functional impacts depending on the stage of brain maturation at the time of the challenge.
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Affiliation(s)
- Julia E Dziabis
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA.,Department of Neurobiology, Duke University, Durham, NC, USA
| | - Staci D Bilbo
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA. .,Department of Neurobiology, Duke University, Durham, NC, USA.
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26
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Hart CG, Karimi-Abdolrezaee S. Recent insights on astrocyte mechanisms in CNS homeostasis, pathology, and repair. J Neurosci Res 2021; 99:2427-2462. [PMID: 34259342 DOI: 10.1002/jnr.24922] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/06/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022]
Abstract
Astrocytes play essential roles in development, homeostasis, injury, and repair of the central nervous system (CNS). Their development is tightly regulated by distinct spatial and temporal cues during embryogenesis and into adulthood throughout the CNS. Astrocytes have several important responsibilities such as regulating blood flow and permeability of the blood-CNS barrier, glucose metabolism and storage, synapse formation and function, and axon myelination. In CNS pathologies, astrocytes also play critical parts in both injury and repair mechanisms. Upon injury, they undergo a robust phenotypic shift known as "reactive astrogliosis," which results in both constructive and deleterious outcomes. Astrocyte activation and migration at the site of injury provides an early defense mechanism to minimize the extent of injury by enveloping the lesion area. However, astrogliosis also contributes to the inhibitory microenvironment of CNS injury and potentiate secondary injury mechanisms, such as inflammation, oxidative stress, and glutamate excitotoxicity, which facilitate neurodegeneration in CNS pathologies. Intriguingly, reactive astrocytes are increasingly a focus in current therapeutic strategies as their activation can be modulated toward a neuroprotective and reparative phenotype. This review will discuss recent advancements in knowledge regarding the development and role of astrocytes in the healthy and pathological CNS. We will also review how astrocytes have been genetically modified to optimize their reparative potential after injury, and how they may be transdifferentiated into neurons and oligodendrocytes to promote repair after CNS injury and neurodegeneration.
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Affiliation(s)
- Christopher G Hart
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
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27
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Kono R, Ikegaya Y, Koyama R. Phagocytic Glial Cells in Brain Homeostasis. Cells 2021; 10:1348. [PMID: 34072424 PMCID: PMC8229427 DOI: 10.3390/cells10061348] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Phagocytosis by glial cells has been shown to play an important role in maintaining brain homeostasis. Microglia are currently considered to be the major phagocytes in the brain parenchyma, and these cells phagocytose a variety of materials, including dead cell debris, abnormally aggregated proteins, and, interestingly, the functional synapses of living neurons. The intracellular signaling mechanisms that regulate microglial phagocytosis have been studied extensively, and several important factors, including molecules known as "find me" signals and "eat me" signals and receptors on microglia that are involved in phagocytosis, have been identified. In addition, recent studies have revealed that astrocytes, which are another major glial cell in the brain parenchyma, also have phagocytic abilities. In this review, we will discuss the roles of microglia and astrocytes in phagocytosis-mediated brain homeostasis, focusing on the characteristics and differences of their phagocytic abilities.
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Affiliation(s)
- Rena Kono
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
- Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City 565-0871, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
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28
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Casali BT, Reed-Geaghan EG. Microglial Function and Regulation during Development, Homeostasis and Alzheimer's Disease. Cells 2021; 10:957. [PMID: 33924200 PMCID: PMC8074610 DOI: 10.3390/cells10040957] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022] Open
Abstract
Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer's disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.
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Affiliation(s)
| | - Erin G. Reed-Geaghan
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA;
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29
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Sokolova D, Childs T, Hong S. Insight into the role of phosphatidylserine in complement-mediated synapse loss in Alzheimer's disease. Fac Rev 2021; 10:19. [PMID: 33718936 PMCID: PMC7946395 DOI: 10.12703/r/10-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The innate immune system plays an integral role in the brain. Synaptic pruning, a fundamental process in developmental circuit refinement, is partially mediated by neuroimmune signalling at the synapse. In particular, microglia, the major tissue-resident macrophages of the brain, and the classical complement cascade, an innate immune pathway that aids in the clearance of unwanted material, have been implicated in mediating synapse elimination. Emerging data suggest that improper signalling of the innate immune pathway at the synapse leads to pathological synapse loss in age-related neurodegenerative diseases, including Alzheimer's disease. Now the key questions are whether synapses are targeted by complement and, if so, which synapses are vulnerable to elimination. Here, we review recent work implicating C1q, the initiator of the classical complement cascade, and surrounding glia as mediators of synapse loss. We examine how synapses could undergo apoptosis-like pathways in the Alzheimer brain, which may lead to the externalisation of phosphatidylserine on synapses. Finally, we discuss potential roles for microglia and astrocytes in this 'synaptic apoptosis'. Critical insight into neuroimmune regulatory pathways on synapses will be key to developing effective targets against pathological synapse loss in dementia.
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Affiliation(s)
- Dimitra Sokolova
- UK Dementia Research Institute, Institute of Neurology, University College London, Gower Street, London WC1E 6BT, UK
| | - Thomas Childs
- UK Dementia Research Institute, Institute of Neurology, University College London, Gower Street, London WC1E 6BT, UK
| | - Soyon Hong
- UK Dementia Research Institute, Institute of Neurology, University College London, Gower Street, London WC1E 6BT, UK
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30
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Andoh M, Koyama R. Microglia regulate synaptic development and plasticity. Dev Neurobiol 2021; 81:568-590. [PMID: 33583110 PMCID: PMC8451802 DOI: 10.1002/dneu.22814] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
Synapses are fundamental structures of neural circuits that transmit information between neurons. Thus, the process of neural circuit formation via proper synaptic connections shapes the basis of brain functions and animal behavior. Synapses continuously undergo repeated formation and elimination throughout the lifetime of an organism, reflecting the dynamics of neural circuit function. The structural transformation of synapses has been described mainly in relation to neural activity-dependent strengthening and weakening of synaptic functions, that is, functional plasticity of synapses. An increasing number of studies have unveiled the roles of microglia, brain-resident immune cells that survey the brain parenchyma with highly motile processes, in synapse formation and elimination as well as in regulating synaptic function. Over the past 15 years, the molecular mechanisms underlying microglia-dependent regulation of synaptic plasticity have been thoroughly studied, and researchers have reported that the disruption of microglia-dependent regulation causes synaptic dysfunction that leads to brain diseases. In this review, we will broadly introduce studies that report the roles of microglia in synaptic plasticity and the possible underlying molecular mechanisms.
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Affiliation(s)
- Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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31
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Raiders S, Han T, Scott-Hewitt N, Kucenas S, Lew D, Logan MA, Singhvi A. Engulfed by Glia: Glial Pruning in Development, Function, and Injury across Species. J Neurosci 2021; 41:823-833. [PMID: 33468571 PMCID: PMC7880271 DOI: 10.1523/jneurosci.1660-20.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Phagocytic activity of glial cells is essential for proper nervous system sculpting, maintenance of circuitry, and long-term brain health. Glial engulfment of apoptotic cells and superfluous connections ensures that neuronal connections are appropriately refined, while clearance of damaged projections and neurotoxic proteins in the mature brain protects against inflammatory insults. Comparative work across species and cell types in recent years highlights the striking conservation of pathways that govern glial engulfment. Many signaling cascades used during developmental pruning are re-employed in the mature brain to "fine tune" synaptic architecture and even clear neuronal debris following traumatic events. Moreover, the neuron-glia signaling events required to trigger and perform phagocytic responses are impressively conserved between invertebrates and vertebrates. This review offers a compare-and-contrast portrayal of recent findings that underscore the value of investigating glial engulfment mechanisms in a wide range of species and contexts.
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Affiliation(s)
- Stephan Raiders
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
| | - Taeho Han
- UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, California 94158
| | - Nicole Scott-Hewitt
- F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Boston, Massachusetts 02115
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Deborah Lew
- Department of Biological Sciences, Fordham University, Bronx, New York 10458
| | - Mary A Logan
- Jungers Center, Department of Neurology, Oregon Health and Science University, Portland, Oregon 97239
| | - Aakanksha Singhvi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
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32
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Subramanian J, Savage JC, Tremblay MÈ. Synaptic Loss in Alzheimer's Disease: Mechanistic Insights Provided by Two-Photon in vivo Imaging of Transgenic Mouse Models. Front Cell Neurosci 2020; 14:592607. [PMID: 33408613 PMCID: PMC7780885 DOI: 10.3389/fncel.2020.592607] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/25/2020] [Indexed: 01/05/2023] Open
Abstract
Synapse loss is the strongest correlate for cognitive decline in Alzheimer's disease. The mechanisms underlying synapse loss have been extensively investigated using mouse models expressing genes with human familial Alzheimer's disease mutations. In this review, we summarize how multiphoton in vivo imaging has improved our understanding of synapse loss mechanisms associated with excessive amyloid in the living animal brain. We also discuss evidence obtained from these imaging studies for the role of cell-intrinsic calcium dyshomeostasis and cell-extrinsic activities of microglia, which are the immune cells of the brain, in mediating synapse loss.
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Affiliation(s)
- Jaichandar Subramanian
- Department of Pharmacology & Toxicology, University of Kansas, Lawrence, KS, United States
| | - Julie C Savage
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.,Department of Molecular Medicine, Université Laval, Québec City, QC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
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33
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Ibach M, Mathews M, Linnartz-Gerlach B, Theil S, Kumar S, Feederle R, Brüstle O, Neumann H, Walter J. A reporter cell system for the triggering receptor expressed on myeloid cells 2 reveals differential effects of disease-associated variants on receptor signaling and activation by antibodies against the stalk region. Glia 2020; 69:1126-1139. [PMID: 33314333 DOI: 10.1002/glia.23953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/31/2022]
Abstract
The triggering receptor expressed on myeloid cells 2 (TREM2) is an immune receptor expressed on myeloid-derived cell types. The extracellular immunoglobulin-like domain of TREM2 binds anionic ligands including Apolipoprotein E and Amyloid-β. The transmembrane domain interacts with its adaptor protein DAP12/TYROBP that is responsible for propagation of downstream signaling upon ligand interaction. Several sequence variants of TREM2 have been linked to different neurodegenerative diseases including Alzheimer's disease. Here, we generated HEK 293 Flp-In cell lines stably expressing human TREM2 and DAP12 using a bicistronic construct with a T2A linker sequence allowing initial expression of both proteins in stoichiometric amounts. Cell biological and biochemical analyses revealed transport of TREM2 to the cell surface, and canonical sequential proteolytic processing and shedding of TREM2 (sTREM2). The functionality of this cell system was demonstrated by detection of phosphorylated spleen tyrosine kinase (SYK) upon stimulation of TREM2 with the anionic membrane lipid phosphatidylserine or anti-TREM2 antibodies. Using this cell model, we demonstrated impaired signaling of disease associated TREM2 variants. We also identified a monoclonal antibody against the stalk region of TREM2 with agonistic activity. Activation of TREM2-DAP12 signaling with the monoclonal antibody and the partial loss of function of disease associated variants were recapitulated in induced pluripotent stem cell derived microglia. Thus, this reporter cell model represents a suitable experimental system to investigate signaling of TREM2 variants, and for the identification of ligands and compounds that modulate TREM2-DAP12 signaling. MAIN POINTS: Disease associated variants impair the signaling activity of TREM2 by distinct mechanisms. Targeting the stalk region of TREM2 with bivalent antibodies activates TREM2 signaling.
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Affiliation(s)
- Melanie Ibach
- Department of Neurology, University of Bonn, Bonn, Germany
| | | | - Bettina Linnartz-Gerlach
- Neural Regeneration, Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Sandra Theil
- Department of Neurology, University of Bonn, Bonn, Germany
| | - Sathish Kumar
- Department of Neurology, University of Bonn, Bonn, Germany
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Core Facility Monoclonal Antibodies, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Oliver Brüstle
- Life and Brain GmbH, Bonn, Germany.,Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Jochen Walter
- Department of Neurology, University of Bonn, Bonn, Germany
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Greve HJ, Mumaw CL, Messenger EJ, Kodavanti PRS, Royland JL, Kodavanti UP, Block ML. Diesel exhaust impairs TREM2 to dysregulate neuroinflammation. J Neuroinflammation 2020; 17:351. [PMID: 33222683 PMCID: PMC7682066 DOI: 10.1186/s12974-020-02017-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/29/2020] [Indexed: 01/07/2023] Open
Abstract
Background Air pollution has been linked to neurodegenerative diseases, including Alzheimer’s disease (AD), and the underlying neuroimmune mechanisms remain poorly understood. TREM2 is a myeloid cell membrane receptor that is a key regulator of disease-associated microglia (DAM) cells, where loss-of-function TREM2 mutations are associated with an increased risk of AD. At present, the basic function of TREM2 in neuroinflammation is a point of controversy. Further, the impact of air pollution on TREM2 and the DAM phenotype is largely unknown. Using diesel exhaust (DE) as a model of urban air pollution exposure, we sought to address its impact on TREM2 expression, the DAM phenotype, the association of microglia with the neurovasculature, and the role of TREM2 in DE-induced neuroinflammation. Methods WYK rats were exposed for 4 weeks to DE (0, 50, 150, 500 μg/m3) by inhalation. DE particles (DEP) were administered intratracheally once (600 μg/mouse) or 8 times (100 μg/mouse) across 28 days to male mice (Trem2+/+, Trem2−/−, PHOX+/+, and PHOX−/−). Results Rats exposed to DE exhibited inverted-U patterns of Trem2 mRNA expression in the hippocampus and frontal cortex, while TREM2 protein was globally diminished, indicating impaired TREM2 expression. Analysis of DAM markers Cx3Cr1, Lyz2, and Lpl in the frontal cortex and hippocampus showed inverted-U patterns of expression as well, supporting dysregulation of the DAM phenotype. Further, microglial-vessel association decreased with DE inhalation in a dose-dependent manner. Mechanistically, intratracheal administration of DEP increased Tnf (TNFα), Ncf1 (p47PHOX), and Ncf2 (p67PHOX) mRNA expression in only Trem2+/+ mice, where Il1b (IL-1β) expression was elevated in only Trem2−/− mice, emphasizing an important role for TREM2 in DEP-induced neuroinflammation. Conclusions Collectively, these findings reveal a novel role for TREM2 in how air pollution regulates neuroinflammation and provides much needed insight into the potential mechanisms linking urban air pollution to AD. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-020-02017-7.
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Affiliation(s)
- Hendrik J Greve
- Department of Pharmacology and Toxicology, The Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 West 15th Street, NB 214D, Indianapolis, IN, 46202, USA
| | - Christen L Mumaw
- Department of Pharmacology and Toxicology, The Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 West 15th Street, NB 214D, Indianapolis, IN, 46202, USA
| | - Evan J Messenger
- Department of Pharmacology and Toxicology, The Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 West 15th Street, NB 214D, Indianapolis, IN, 46202, USA
| | - Prasada R S Kodavanti
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Joyce L Royland
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Urmila P Kodavanti
- Cardiopulmonary and Immunotoxicology Branch, Public Health and Integrated Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Michelle L Block
- Department of Pharmacology and Toxicology, The Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 West 15th Street, NB 214D, Indianapolis, IN, 46202, USA.
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Seol Y, Ki S, Ryu HL, Chung S, Lee J, Ryu H. How Microglia Manages Non-cell Autonomous Vicious Cycling of Aβ Toxicity in the Pathogenesis of AD. Front Mol Neurosci 2020; 13:593724. [PMID: 33328884 PMCID: PMC7718019 DOI: 10.3389/fnmol.2020.593724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/20/2020] [Indexed: 01/17/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease and a common form of dementia that affects cognition and memory mostly in aged people. AD pathology is characterized by the accumulation of β-amyloid (Aβ) senile plaques and the neurofibrillary tangles of phosphorylated tau, resulting in cell damage and neurodegeneration. The extracellular deposition of Aβ is regarded as an important pathological marker and a principal-agent of neurodegeneration. However, the exact mechanism of Aβ-mediated pathogenesis is not fully understood yet. Recently, a growing body of evidence provides novel insights on the major role of microglia and its non-cell-autonomous cycling of Aβ toxicity. Hence, this article provides a comprehensive overview of microglia as a significant player in uncovering the underlying disease mechanisms of AD.
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Affiliation(s)
- YunHee Seol
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Soomin Ki
- Department of Brain and Cognitive Science, Ewha Womens University, Seoul, South Korea
| | - Hannah L Ryu
- Department of Neurology, Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, United States
| | - Sooyoung Chung
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Junghee Lee
- Department of Neurology, Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, United States.,VA Boston Healthcare System, Boston, MA, United States
| | - Hoon Ryu
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Department of Neurology, Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, United States
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Tremblay ME, Madore C, Bordeleau M, Tian L, Verkhratsky A. Neuropathobiology of COVID-19: The Role for Glia. Front Cell Neurosci 2020; 14:592214. [PMID: 33304243 PMCID: PMC7693550 DOI: 10.3389/fncel.2020.592214] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/07/2020] [Indexed: 12/18/2022] Open
Abstract
SARS-CoV-2, which causes the Coronavirus Disease 2019 (COVID-19) pandemic, has a brain neurotropism through binding to the receptor angiotensin-converting enzyme 2 expressed by neurones and glial cells, including astrocytes and microglia. Systemic infection which accompanies severe cases of COVID-19 also triggers substantial increase in circulating levels of chemokines and interleukins that compromise the blood-brain barrier, enter the brain parenchyma and affect its defensive systems, astrocytes and microglia. Brain areas devoid of a blood-brain barrier such as the circumventricular organs are particularly vulnerable to circulating inflammatory mediators. The performance of astrocytes and microglia, as well as of immune cells required for brain health, is considered critical in defining the neurological damage and neurological outcome of COVID-19. In this review, we discuss the neurotropism of SARS-CoV-2, the implication of neuroinflammation, adaptive and innate immunity, autoimmunity, as well as astrocytic and microglial immune and homeostatic functions in the neurological and psychiatric aspects of COVID-19. The consequences of SARS-CoV-2 infection during ageing, in the presence of systemic comorbidities, and for the exposed pregnant mother and foetus are also covered.
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Affiliation(s)
- Marie-Eve Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Charlotte Madore
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, Bordeaux, France
| | - Maude Bordeleau
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
| | - Li Tian
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
- Psychiatry Research Centre, Peking University Health Science Center, Beijing Huilongguan Hospital, Beijing, China
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Neurosciences, University of the Basque Country Universidad del País Vasco/Euskal Herriko Unibertsitatea, Leioa, Spain
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Loss of TREM2 Confers Resilience to Synaptic and Cognitive Impairment in Aged Mice. J Neurosci 2020; 40:9552-9563. [PMID: 33139402 DOI: 10.1523/jneurosci.2193-20.2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/12/2020] [Accepted: 10/27/2020] [Indexed: 11/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor exclusively expressed by microglia in the brain, modulates microglial immune homeostasis. Human genetic studies have shown that the loss-of-function mutations in TREM2 signaling are strongly associated with an elevated risk of age-related neurodegenerative diseases including Alzheimer's disease (AD). Numerous studies have investigated the impact of TREM2 deficiency in the pathogenic process of AD. However, the role of TREM2 in shaping neuronal and cognitive function during normal aging is underexplored. In the present study, we employed behavioral, electrophysiological, and biochemical approaches to assess cognitive and synaptic function in male and female young and aged TREM2-deficient (Trem2-/-) mice compared with age-matched, sex-matched, and genetic background-matched wild-type (WT) C57BL/6J controls. Young Trem2-/- mice exhibited normal cognitive function and synaptic plasticity but had increased dendritic spine density compared with young WT. Unexpectedly, aged Trem2-/- mice showed superior cognitive performance compared with aged WT controls. Consistent with the behavioral data, aged Trem2-/- mice displayed significantly enhanced hippocampal long-term potentiation (LTP) and increased dendritic spine density and synaptic markers compared with aged WT mice. Taken together, these findings suggest that loss of TREM2 affects the neuronal structure and confers resilience to age-related synaptic and cognitive impairment during non-pathogenic aging.SIGNIFICANCE STATEMENT Microglia are innate immune cells of the brain that orchestrates neurodevelopment, synaptic function, and immune response to environmental stimuli. Microglial triggering receptor expressed on myeloid cells 2 (TREM2) signaling plays pivotal roles in regulating these functions and loss of TREM2 signaling leads to increased risk of developing age-related neurologic disorders. However, the neurologic role of TREM2 in normal aging is poorly understood. The results of the present study unveil the positive impacts of TREM2 deficiency on cognitive and synaptic function during aging and suggest that TREM2 may exert detrimental effects on neuronal function. The possibility of age-related negative impacts from TREM2 is critically important since TREM2 has emerged as a major therapeutic target for Alzheimer's dementia.
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38
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Jadhav VS, Lin PBC, Pennington T, Di Prisco GV, Jannu AJ, Xu G, Moutinho M, Zhang J, Atwood BK, Puntambekar SS, Bissel SJ, Oblak AL, Landreth GE, Lamb BT. Trem2 Y38C mutation and loss of Trem2 impairs neuronal synapses in adult mice. Mol Neurodegener 2020; 15:62. [PMID: 33115519 PMCID: PMC7594478 DOI: 10.1186/s13024-020-00409-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Triggering receptor expressed on myeloid cells 2 (TREM2) is expressed in the brain exclusively on microglia and genetic variants are linked to neurodegenerative diseases including Alzheimer's disease (AD), frontotemporal dementia (FTD) and Nasu Hakola Disease (NHD). The Trem2 variant R47H, confers substantially elevated risk of developing late onset Alzheimer's disease, while NHD-linked Trem2 variants like Y38C, are associated with development of early onset dementia with white matter pathology. However, it is not known how these Trem2 species, predisposes individuals to presenile dementia. METHODS To investigate if Trem2 Y38C or loss of Trem2 alters neuronal function we generated a novel mouse model to introduce the NHD Trem2 Y38C variant in murine Trem2 using CRISPR/Cas9 technology. Trem2Y38C/Y38C and Trem2-/- mice were assessed for Trem2 expression, differentially expressed genes, synaptic protein levels and synaptic plasticity using biochemical, electrophysiological and transcriptomic approaches. RESULTS While mice harboring the Trem2 Y38C exhibited normal expression levels of TREM2, the pathological outcomes phenocopied Trem2-/- mice at 6 months. Transcriptomic analysis revealed altered expression of neuronal and oligodendrocytes/myelin genes. We observed regional decreases in synaptic protein levels, with the most affected synapses in the hippocampus. These alterations were associated with reduced synaptic plasticity. CONCLUSION Our findings provide in vivo evidence that Trem2 Y38C disrupts normal TREM2 functions. Trem2Y38C/Y38C and Trem2-/- mice demonstrated altered gene expression, changes in microglia morphology, loss of synaptic proteins and reduced hippocampal synaptic plasticity at 6 months in absence of any pathological triggers like amyloid. This suggests TREM2 impacts neuronal functions providing molecular insights on the predisposition of individuals with TREM2 variants resulting in presenile dementia.
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Affiliation(s)
- Vaishnavi S Jadhav
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Peter B C Lin
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Taylor Pennington
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Gonzalo Viana Di Prisco
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Asha Jacob Jannu
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 462020, USA
| | - Guixiang Xu
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Miguel Moutinho
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Jie Zhang
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Brady K Atwood
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Shweta S Puntambekar
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Stephanie J Bissel
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Adrian L Oblak
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gary E Landreth
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Bruce T Lamb
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA.
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Bordeleau M, Lacabanne C, Fernández de Cossío L, Vernoux N, Savage JC, González-Ibáñez F, Tremblay MÈ. Microglial and peripheral immune priming is partially sexually dimorphic in adolescent mouse offspring exposed to maternal high-fat diet. J Neuroinflammation 2020; 17:264. [PMID: 32891154 PMCID: PMC7487673 DOI: 10.1186/s12974-020-01914-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
Background Maternal nutrition is critical for proper fetal development. While increased nutrient intake is essential during pregnancy, an excessive consumption of certain nutrients, like fat, can lead to long-lasting detrimental consequences on the offspring. Animal work investigating the consequences of maternal high-fat diet (mHFD) revealed in the offspring a maternal immune activation (MIA) phenotype associated with increased inflammatory signals. This inflammation was proposed as one of the mechanisms causing neuronal circuit dysfunction, notably in the hippocampus, by altering the brain-resident macrophages—microglia. However, the understanding of mechanisms linking inflammation and microglial activities to pathological brain development remains limited. We hypothesized that mHFD-induced inflammation could prime microglia by altering their specific gene expression signature, population density, and/or functions. Methods We used an integrative approach combining molecular (i.e., multiplex-ELISA, rt-qPCR) and cellular (i.e., histochemistry, electron microscopy) techniques to investigate the effects of mHFD (saturated and unsaturated fats) vs control diet on inflammatory priming, as well as microglial transcriptomic signature, density, distribution, morphology, and ultrastructure in mice. These analyses were performed on the mothers and/or their adolescent offspring at postnatal day 30. Results Our study revealed that mHFD results in MIA defined by increased circulating levels of interleukin (IL)-6 in the mothers. This phenotype was associated with an exacerbated inflammatory response to peripheral lipopolysaccharide in mHFD-exposed offspring of both sexes. Microglial morphology was also altered, and there were increased microglial interactions with astrocytes in the hippocampus CA1 of mHFD-exposed male offspring, as well as decreased microglia-associated extracellular space pockets in the same region of mHFD-exposed offspring of the two sexes. A decreased mRNA expression of the inflammatory-regulating cytokine Tgfb1 and microglial receptors Tmem119, Trem2, and Cx3cr1 was additionally measured in the hippocampus of mHFD-exposed offspring, especially in males. Conclusions Here, we described how dietary habits during pregnancy and nurturing, particularly the consumption of an enriched fat diet, can influence peripheral immune priming in the offspring. We also found that microglia are affected in terms of gene expression signature, morphology, and interactions with the hippocampal parenchyma, in a partially sexually dimorphic manner, which may contribute to the adverse neurodevelopmental outcomes on the offspring.
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Affiliation(s)
- Maude Bordeleau
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.,Cerebral Imaging Center, Douglas Mental Health University Institute, McGill University, Montréal, QC, Canada
| | - Chloé Lacabanne
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | | | - Nathalie Vernoux
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Julie C Savage
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.,Département de médecine moléculaire, Université Laval, Québec, QC, Canada
| | - Fernando González-Ibáñez
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.,Département de médecine moléculaire, Université Laval, Québec, QC, Canada
| | - Marie-Ève Tremblay
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada. .,Département de médecine moléculaire, Université Laval, Québec, QC, Canada. .,Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada. .,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada. .,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
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40
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Matejuk A, Ransohoff RM. Crosstalk Between Astrocytes and Microglia: An Overview. Front Immunol 2020; 11:1416. [PMID: 32765501 PMCID: PMC7378357 DOI: 10.3389/fimmu.2020.01416] [Citation(s) in RCA: 220] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
Based on discoveries enabled by new technologies and analysis using novel computational tools, neuroscience can be re-conceived in terms of information exchange in dense networks of intercellular connections rather than in the context of individual populations, such as glia or neurons. Cross-talk between neurons and microglia or astrocytes has been addressed, however, the manner in which non-neuronal cells communicate and interact remains less well-understood. We review this intriguing crosstalk among CNS cells, focusing on astrocytes and microglia and how it contributes to brain development and neurodegenerative diseases. The goal of studying these intercellular communications is to promote our ability to combat incurable neurological disorders.
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Affiliation(s)
- Agata Matejuk
- Department of Immunology, Collegium Medicum, University of Zielona Góra, Zielona Góra, Poland
| | - Richard M Ransohoff
- Third Rock Ventures, Boston, MA, United States.,Department of Cell Biology, Harvard Medical School, Boston, MA, United States
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41
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Yang J, Fu Z, Zhang X, Xiong M, Meng L, Zhang Z. TREM2 ectodomain and its soluble form in Alzheimer's disease. J Neuroinflammation 2020; 17:204. [PMID: 32635934 PMCID: PMC7341574 DOI: 10.1186/s12974-020-01878-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a receptor mainly expressed on the surface of microglia. It mediates multiple pathophysiological processes in various diseases. Recently, TREM2 has been found to play a role in the development of Alzheimer's disease (AD). TREM2 is a transmembrane protein that is specifically expressed on microglia in the brain. It contains a long ectodomain that directly interacts with the extracellular environment to regulate microglial function. The ectodomain of TREM2 is processed by a disintegrin and metalloprotease, resulting in the release of a soluble form of TREM2 (sTREM2). Recent studies have demonstrated that sTREM2 is a bioactive molecule capable of binding ligands, activating microglia, and regulating immune responses during the AD continuum. Clinical studies revealed that sTREM2 level is elevated in cerebrospinal fluid (CSF) of AD patients, and the sTREM2 level is positively correlated with the levels of classical CSF biomarkers, namely t-tau and p-tau, indicating that it is a reliable predictor of the early stages of AD. Herein, we summarize the key results on the generation, structure, and function of sTREM2 to provide new insights into TREM2-related mechanisms underlying AD pathogenesis and to promote the development of TREM2-based therapeutic strategy.
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Affiliation(s)
- Jiaolong Yang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhihui Fu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Xingyu Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Min Xiong
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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Marsters CM, Nesan D, Far R, Klenin N, Pittman QJ, Kurrasch DM. Embryonic microglia influence developing hypothalamic glial populations. J Neuroinflammation 2020; 17:146. [PMID: 32375817 PMCID: PMC7201702 DOI: 10.1186/s12974-020-01811-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/13/2020] [Indexed: 11/15/2022] Open
Abstract
Background Although historically microglia were thought to be immature in the fetal brain, evidence of purposeful interactions between these immune cells and nearby neural progenitors is becoming established. Here, we examined the influence of embryonic microglia on gliogenesis within the developing tuberal hypothalamus, a region later important for energy balance, reproduction, and thermoregulation. Methods We used immunohistochemistry to quantify the location and numbers of glial cells in the embryonic brain (E13.5–E17.5), as well as a pharmacological approach (i.e., PLX5622) to knock down fetal microglia. We also conducted cytokine and chemokine analyses on embryonic brains in the presence or absence of microglia, and a neurosphere assay to test the effects of the altered cytokines on hypothalamic progenitor behaviors. Results We identified a subpopulation of activated microglia that congregated adjacent to the third ventricle alongside embryonic Olig2+ neural progenitor cells (NPCs) that are destined to give rise to oligodendrocyte and astrocyte populations. In the absence of microglia, we observed an increase in Olig2+ glial progenitor cells that remained at the ventricle by E17.5 and a concomitant decrease of these Olig2+ cells in the mantle zone, indicative of a delay in migration of these precursor cells. A further examination of maturing oligodendrocytes in the hypothalamic grey and white matter area in the absence of microglia revealed migrating oligodendrocyte progenitor cells (OPCs) within the grey matter at E17.5, a time point when OPCs begin to slow their migration. Finally, quantification of cytokine and chemokine signaling in ex vivo E15.5 hypothalamic cultures +/− microglia revealed decreases in the protein levels of several cytokines in the absence of microglia. We assayed the influence of two downregulated cytokines (CCL2 and CXCL10) on neurosphere-forming capacity and lineage commitment of hypothalamic NPCs in culture and showed an increase in NPC proliferation as well as neuronal and oligodendrocyte differentiation. Conclusion These data demonstrate that microglia influence gliogenesis in the developing tuberal hypothalamus.
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Affiliation(s)
- Candace M Marsters
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Dinushan Nesan
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Rena Far
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Natalia Klenin
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Quentin J Pittman
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Deborah M Kurrasch
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. .,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada. .,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.
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Lee J, Kim DE, Griffin P, Sheehan PW, Kim D, Musiek ES, Yoon S. Inhibition of REV-ERBs stimulates microglial amyloid-beta clearance and reduces amyloid plaque deposition in the 5XFAD mouse model of Alzheimer's disease. Aging Cell 2020; 19:e13078. [PMID: 31800167 PMCID: PMC6996949 DOI: 10.1111/acel.13078] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 07/30/2019] [Accepted: 10/06/2019] [Indexed: 12/21/2022] Open
Abstract
A promising new therapeutic target for the treatment of Alzheimer's disease (AD) is the circadian system. Although patients with AD are known to have abnormal circadian rhythms and suffer sleep disturbances, the role of the molecular clock in regulating amyloid-beta (Aβ) pathology is still poorly understood. Here, we explored how the circadian repressors REV-ERBα and β affected Aβ clearance in mouse microglia. We discovered that, at Circadian time 4 (CT4), microglia expressed higher levels of the master clock protein BMAL1 and more rapidly phagocytosed fibrillary Aβ1-42 (fAβ1-42 ) than at CT12. BMAL1 directly drives transcription of REV-ERB proteins, which are implicated in microglial activation. Interestingly, pharmacological inhibition of REV-ERBs with the small molecule antagonist SR8278 or genetic knockdown of REV-ERBs-accelerated microglial uptake of fAβ1-42 and increased transcription of BMAL1. SR8278 also promoted microglia polarization toward a phagocytic M2-like phenotype with increased P2Y12 receptor expression. Finally, constitutive deletion of Rev-erbα in the 5XFAD model of AD decreased amyloid plaque number and size and prevented plaque-associated increases in disease-associated microglia markers including TREM2, CD45, and Clec7a. Altogether, our work suggests a novel strategy for controlling Aβ clearance and neuroinflammation by targeting REV-ERBs and provides new insights into the role of REV-ERBs in AD.
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MESH Headings
- ARNTL Transcription Factors/metabolism
- Alzheimer Disease/pathology
- Amyloid beta-Peptides/chemical synthesis
- Amyloid beta-Peptides/metabolism
- Animals
- CLOCK Proteins/metabolism
- Cell Line
- Circadian Clocks/genetics
- Disease Models, Animal
- Isoquinolines/pharmacology
- Macrophages/metabolism
- Mice
- Mice, Knockout
- Microglia/metabolism
- Nuclear Receptor Subfamily 1, Group D, Member 1/antagonists & inhibitors
- Nuclear Receptor Subfamily 1, Group D, Member 1/metabolism
- Plaque, Amyloid/genetics
- Plaque, Amyloid/metabolism
- Plaque, Amyloid/pathology
- RNA, Small Interfering
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Purinergic P2Y12/drug effects
- Receptors, Purinergic P2Y12/metabolism
- Repressor Proteins/antagonists & inhibitors
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Synapses/genetics
- Synapses/metabolism
- Thiophenes/pharmacology
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Affiliation(s)
- Jiyeon Lee
- Department of Brain ScienceAsan Medical CenterUniversity of Ulsan College of MedicineSeoulKorea
- Department of NeurologyHope Center for Neurological DisordersWashington University School of MedicineSt. LouisMOUSA
| | - Do Eon Kim
- Department of Brain ScienceAsan Medical CenterUniversity of Ulsan College of MedicineSeoulKorea
| | - Percy Griffin
- Department of NeurologyHope Center for Neurological DisordersWashington University School of MedicineSt. LouisMOUSA
| | - Patrick W. Sheehan
- Department of NeurologyHope Center for Neurological DisordersWashington University School of MedicineSt. LouisMOUSA
| | - Dong‐Hou Kim
- Department of Brain ScienceAsan Medical CenterUniversity of Ulsan College of MedicineSeoulKorea
| | - Erik S Musiek
- Department of NeurologyHope Center for Neurological DisordersWashington University School of MedicineSt. LouisMOUSA
| | - Seung‐Yong Yoon
- Department of Brain ScienceAsan Medical CenterUniversity of Ulsan College of MedicineSeoulKorea
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