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Mattei D, Ivanov A, Hammer J, Ugursu B, Schalbetter S, Richetto J, Weber-Stadlbauer U, Mueller F, Scarborough J, Wolf SA, Kettenmann H, Wollscheid B, Beule D, Meyer U. Microglia undergo molecular and functional adaptations to dark and light phases in male laboratory mice. Brain Behav Immun 2024; 120:571-583. [PMID: 38986723 DOI: 10.1016/j.bbi.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/20/2024] [Accepted: 07/06/2024] [Indexed: 07/12/2024] Open
Abstract
Microglia are increasingly recognized to contribute to brain health and disease. Preclinical studies using laboratory rodents are essential to advance our understanding of the physiological and pathophysiological roles of these cells in the central nervous system. Rodents are nocturnal animals, and they are mostly maintained in a defined light-dark cycle within animal facilities, with many laboratories investigating the molecular and functional profiles of microglia exclusively during the animals' light (sleep) phase. However, only a few studies have considered possible differences in microglial functions between the active and sleep phases. Based on initial evidence suggesting that microglial intrinsic clock genes can affect their phenotypes, we sought to investigate differences in transcriptional, proteotype and functional profiles of microglia between light (sleep) and dark (active) phases, and how these changes are affected in pathological models. We found marked transcriptional and proteotype differences between microglia harvested from male mice during the light or dark phase. Amongst others, these differences related to genes and proteins associated with immune responses, motility, and phagocytosis, which were reflected by functional alterations in microglial synaptic pruning and response to bacterial stimuli. Possibly accounting for such changes, we found RNA and protein regulation in SWI/SNF and NuRD chromatin remodeling complexes between light and dark phases. Importantly, we also show that the time of microglial sample collection influences the nature of microglial transcriptomic changes in a model of immune-mediated neurodevelopmental disorders. Our findings emphasize the importance of considering diurnal factors in studying microglial cells and indicate that implementing a circadian perspective is pivotal for advancing our understanding of their physiological and pathophysiological roles in brain health and disease.
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Affiliation(s)
- Daniele Mattei
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America.
| | - Andranik Ivanov
- Core Unit Bioinformatics, Berlin Institute of Health, Charité-Universitätsmedizin, Berlin, Germany
| | - Jacqueline Hammer
- Institute of Molecular Systems Biology and Department for Health Sciences and Technology, ETH Zürich, Switzerland
| | - Bilge Ugursu
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany; Psychoneuroimmunology, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sina Schalbetter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Juliet Richetto
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Ulrike Weber-Stadlbauer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Flavia Mueller
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Joseph Scarborough
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Susanne A Wolf
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany; Psychoneuroimmunology, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bernd Wollscheid
- Institute of Molecular Systems Biology and Department for Health Sciences and Technology, ETH Zürich, Switzerland
| | - Dieter Beule
- Core Unit Bioinformatics, Berlin Institute of Health, Charité-Universitätsmedizin, Berlin, Germany
| | - Urs Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.
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Deng Q, Wu C, Parker E, Liu TCY, Duan R, Yang L. Microglia and Astrocytes in Alzheimer's Disease: Significance and Summary of Recent Advances. Aging Dis 2024; 15:1537-1564. [PMID: 37815901 PMCID: PMC11272214 DOI: 10.14336/ad.2023.0907] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/07/2023] [Indexed: 10/12/2023] Open
Abstract
Alzheimer's disease, one of the most common forms of dementia, is characterized by a slow progression of cognitive impairment and neuronal loss. Currently, approved treatments for AD are hindered by various side effects and limited efficacy. Despite considerable research, practical treatments for AD have not been developed. Increasing evidence shows that glial cells, especially microglia and astrocytes, are essential in the initiation and progression of AD. During AD progression, activated resident microglia increases the ability of resting astrocytes to transform into reactive astrocytes, promoting neurodegeneration. Extensive clinical and molecular studies show the involvement of microglia and astrocyte-mediated neuroinflammation in AD pathology, indicating that microglia and astrocytes may be potential therapeutic targets for AD. This review will summarize the significant and recent advances of microglia and astrocytes in the pathogenesis of AD in three parts. First, we will review the typical pathological changes of AD and discuss microglia and astrocytes in terms of function and phenotypic changes. Second, we will describe microglia and astrocytes' physiological and pathological role in AD. These roles include the inflammatory response, "eat me" and "don't eat me" signals, Aβ seeding, propagation, clearance, synapse loss, synaptic pruning, remyelination, and demyelination. Last, we will review the pharmacological and non-pharmacological therapies targeting microglia and astrocytes in AD. We conclude that microglia and astrocytes are essential in the initiation and development of AD. Therefore, understanding the new role of microglia and astrocytes in AD progression is critical for future AD studies and clinical trials. Moreover, pharmacological, and non-pharmacological therapies targeting microglia and astrocytes, with specific studies investigating microglia and astrocyte-mediated neuronal damage and repair, may be a promising research direction for future studies regarding AD treatment and prevention.
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Affiliation(s)
- Qianting Deng
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
| | - Chongyun Wu
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
- Laboratory of Regenerative Medicine in Sports Science, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
| | - Emily Parker
- Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Timon Cheng-Yi Liu
- Laboratory of Laser Sports Medicine, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
| | - Rui Duan
- Laboratory of Regenerative Medicine in Sports Science, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
| | - Luodan Yang
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
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Sharp RC, Guenther DT, Farrer MJ. Experimental procedures for flow cytometry of wild-type mouse brain: a systematic review. Front Immunol 2023; 14:1281705. [PMID: 38022545 PMCID: PMC10646240 DOI: 10.3389/fimmu.2023.1281705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Objective The aim of this study was to systematically review the neuroimmunology literature to determine the average immune cell counts reported by flow cytometry in wild-type (WT) homogenized mouse brains. Background Mouse models of gene dysfunction are widely used to study age-associated neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. The importance of the neuroimmune system in these multifactorial disorders has become increasingly evident, and methods to quantify resident and infiltrating immune cells in the brain, including flow cytometry, are necessary. However, there appears to be no consensus on the best approach to perform flow cytometry or quantify/report immune cell counts. The development of more standardized methods would accelerate neuroimmune discovery and validation by meta-analysis. Methods There has not yet been a systematic review of 'neuroimmunology' by 'flow cytometry' via examination of the PROSPERO registry. A protocol for a systematic review was subsequently based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using the Studies, Data, Methods, and Outcomes (SDMO) criteria. Literature searches were conducted in the Google Scholar and PubMed databases. From that search, 900 candidate studies were identified, and 437 studies were assessed for eligibility based on formal exclusion criteria. Results Out of the 437 studies reviewed, 58 were eligible for inclusion and comparative analysis. Each study assessed immune cell subsets within homogenized mouse brains and used flow cytometry. Nonetheless, there was considerable variability in the methods, data analysis, reporting, and results. Descriptive statistics have been presented on the study designs and results, including medians with interquartile ranges (IQRs) and overall means with standard deviations (SD) for specific immune cell counts and their relative proportions, within and between studies. A total of 58 studies reported the most abundant immune cells within the brains were TMEM119+ microglia, bulk CD4+ T cells, and bulk CD8+ T cells. Conclusion Experiments to conduct and report flow cytometry data, derived from WT homogenized mouse brains, would benefit from a more standardized approach. While within-study comparisons are valid, the variability in methods of counting of immune cell populations is too broad for meta-analysis. The inclusion of a minimal protocol with more detailed methods, controls, and standards could enable this nascent field to compare results across studies.
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Affiliation(s)
| | | | - Matthew J. Farrer
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
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Dissing-Olesen L, Walker AJ, Feng Q, Barr HJ, Walker AC, Xie L, Wilton DK, Das I, Benowitz LI, Stevens B. FEAST: A flow cytometry-based toolkit for interrogating microglial engulfment of synaptic and myelin proteins. Nat Commun 2023; 14:6015. [PMID: 37758703 PMCID: PMC10533836 DOI: 10.1038/s41467-023-41448-7] [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: 12/09/2022] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Although engulfment is a hallmark of microglia function, fully validated platforms that facilitate high-throughput quantification of this process are lacking. Here, we present FEAST (Flow cytometric Engulfment Assay for Specific Target proteins), which enables interrogation of in vivo engulfment of synaptic material by brain resident macrophages at single-cell resolution. We optimize FEAST for two different analyses: quantification of fluorescent material inside live cells and of engulfed endogenous proteins within fixed cells. To overcome false-positive engulfment signals, we introduce an approach suitable for interrogating engulfment in microglia from perfusion-fixed tissue. As a proof-of-concept for the specificity and versatility of FEAST, we examine the engulfment of synaptic proteins after optic nerve crush and of myelin in two mouse models of demyelination (treatment with cuprizone and injections of lysolecithin). We find that microglia, but not brain-border associated macrophages, engulf in these contexts. Our work underscores how FEAST can be utilized to gain critical insight into functional neuro-immune interactions that shape development, homeostasis, and disease.
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Affiliation(s)
- Lasse Dissing-Olesen
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02139, USA
| | - Alec J Walker
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02139, USA
| | - Qian Feng
- Department of Neurosurgery, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
| | - Helena J Barr
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02139, USA
| | - Alicia C Walker
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Lili Xie
- Department of Neurosurgery, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
| | - Daniel K Wilton
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02139, USA
| | - Indrani Das
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Larry I Benowitz
- Department of Neurosurgery, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA
- Ophthalmology, Harvard Medical School, Boston, MA, 02115, USA
| | - Beth Stevens
- Department of Neurology, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, 02115, USA.
- Harvard Medical School, Boston, MA, 02115, USA.
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02139, USA.
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, 02115, USA.
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Kahng JA, Xavier AM, Ferro A, Auguste YS, Cheadle L. Integrated high-confidence and high-throughput approaches for quantifying synapse engulfment by oligodendrocyte precursor cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554663. [PMID: 37662250 PMCID: PMC10473697 DOI: 10.1101/2023.08.24.554663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) sculpt neural circuits through the phagocytic engulfment of synapses during development and in adulthood. However, precise techniques for analyzing synapse engulfment by OPCs are limited. Here, we describe a two-pronged cell biological approach for quantifying synapse engulfment by OPCs which merges low- and high-throughput methodologies. In the first method, an adeno-associated virus encoding a pH-sensitive, fluorescently-tagged synaptic marker is expressed in neurons in vivo. This construct allows for the differential labeling of presynaptic inputs that are contained outside of and within acidic phagolysosomal compartments. When followed by immunostaining for markers of OPCs and synapses in lightly fixed tissue, this approach enables the quantification of synapses engulfed by around 30-50 OPCs within a given experiment. In the second method, OPCs isolated from dissociated brain tissue are fixed, incubated with fluorescent antibodies against presynaptic proteins, and then analyzed by flow cytometry. This approach enables the quantification of presynaptic material within tens of thousands of OPCs in less than one week. These methods extend beyond the current imaging-based engulfment assays designed to quantify synaptic phagocytosis by brain-resident immune cells, microglia. Through the integration of these methods, the engulfment of synapses by OPCs can be rigorously quantified at both the individual and populational levels. With minor modifications, these approaches can be adapted to study synaptic phagocytosis by numerous glial cell types in the brain.
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Affiliation(s)
- Jessica A. Kahng
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | | | - Austin Ferro
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | | | - Lucas Cheadle
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
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Albertini G, D'Andrea I, Druart M, Béchade C, Nieves-Rivera N, Etienne F, Le Magueresse C, Rebsam A, Heck N, Maroteaux L, Roumier A. Serotonin sensing by microglia conditions the proper development of neuronal circuits and of social and adaptive skills. Mol Psychiatry 2023; 28:2328-2342. [PMID: 37217677 DOI: 10.1038/s41380-023-02048-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 05/24/2023]
Abstract
The proper maturation of emotional and sensory circuits requires fine-tuning of serotonin (5-HT) level during early postnatal development. Consistently, dysfunctions of the serotonergic system have been associated with neurodevelopmental psychiatric diseases, including autism spectrum disorders (ASD). However, the mechanisms underlying the developmental effects of 5-HT remain partially unknown, one obstacle being the action of 5-HT on different cell types. Here, we focused on microglia, which play a role in brain wiring refinement, and we investigated whether the control of these cells by 5-HT is relevant for neurodevelopment and spontaneous behaviors in mice. Since the main 5-HT sensor in microglia is the 5-HT2B receptor subtype, we prevented 5-HT signaling specifically in microglia by conditional invalidation of the Htr2b gene in these cells. We observed that abrogating the serotonergic control of microglia during early postnatal development affects the phagolysosomal compartment of these cells and their proximity to dendritic spines and perturbs neuronal circuits maturation. Furthermore, this early ablation of microglial 5-HT2B receptors leads to adult hyperactivity in a novel environment and behavioral defects in sociability and flexibility. Importantly, we show that these behavioral alterations result from a developmental effect, since they are not observed when microglial Htr2b invalidation is induced later, at P30 onward. Thus, a primary alteration of 5-HT sensing in microglia, during a critical time window between birth and P30, is sufficient to impair social and flexibility skills. This link between 5-HT and microglia may explain the association between serotonergic dysfunctions and behavioral traits like impaired sociability and inadaptability to novelty, which are prominent in psychiatric disorders such as ASD.
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Affiliation(s)
- Giulia Albertini
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | - Ivana D'Andrea
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | - Mélanie Druart
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | - Catherine Béchade
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | | | - Fanny Etienne
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | | | - Alexandra Rebsam
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Nicolas Heck
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine, Institut de Biologie Paris Seine, F-75005, Paris, France
| | - Luc Maroteaux
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France
| | - Anne Roumier
- Sorbonne Université, INSERM, Institut du Fer à Moulin, F-75005, Paris, France.
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Ribarič S. Detecting Early Cognitive Decline in Alzheimer's Disease with Brain Synaptic Structural and Functional Evaluation. Biomedicines 2023; 11:biomedicines11020355. [PMID: 36830892 PMCID: PMC9952956 DOI: 10.3390/biomedicines11020355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
Early cognitive decline in patients with Alzheimer's (AD) is associated with quantifiable structural and functional connectivity changes in the brain. AD dysregulation of Aβ and tau metabolism progressively disrupt normal synaptic function, leading to loss of synapses, decreased hippocampal synaptic density and early hippocampal atrophy. Advances in brain imaging techniques in living patients have enabled the transition from clinical signs and symptoms-based AD diagnosis to biomarkers-based diagnosis, with functional brain imaging techniques, quantitative EEG, and body fluids sampling. The hippocampus has a central role in semantic and episodic memory processing. This cognitive function is critically dependent on normal intrahippocampal connections and normal hippocampal functional connectivity with many cortical regions, including the perirhinal and the entorhinal cortex, parahippocampal cortex, association regions in the temporal and parietal lobes, and prefrontal cortex. Therefore, decreased hippocampal synaptic density is reflected in the altered functional connectivity of intrinsic brain networks (aka large-scale networks), including the parietal memory, default mode, and salience networks. This narrative review discusses recent critical issues related to detecting AD-associated early cognitive decline with brain synaptic structural and functional markers in high-risk or neuropsychologically diagnosed patients with subjective cognitive impairment or mild cognitive impairment.
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Affiliation(s)
- Samo Ribarič
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia
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Wang S, Ding C, Dou C, Zhu Z, Zhang D, Yi Q, Wu H, Xie L, Zhu Z, Song D, Li H. Associations between maternal prenatal depression and neonatal behavior and brain function - Evidence from the functional near-infrared spectroscopy. Psychoneuroendocrinology 2022; 146:105896. [PMID: 36037574 DOI: 10.1016/j.psyneuen.2022.105896] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 08/08/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Maternal prenatal depression is a significant public health issue associated with mental disorders of offspring. This study aimed to determine if maternal prenatal depressive symptoms are associated with changes in neonatal behaviors and brain function at the resting state. METHODS A total of 204 pregnant women were recruited during the third trimester and were evaluated by Edinburgh Postpartum Depression Scale (EPDS). The mother-infant pairs were divided into the depressed group (n = 75) and control group (n = 129) based on the EPDS, using a cut-off value of 10. Cortisol levels in the cord blood and maternal blood collected on admission for delivery were measured. On day three of life, all study newborns were evaluated by the Neonatal Behavior Assessment Scale (NBAS) and 165 infants were evaluated by resting-state functional near-infrared spectroscopy (rs-fNIRS). To minimize the influences of potential bias on the rs-fNIRS results, we used a binary logistic regression model to carry out propensity score matching between the depressed group and the control group. Rs-fNIRS data from 21 pairs of propensity score-matched newborns were used for analysis. The associations between maternal EPDS scores, neonatal NBAS scores, and cortisol levels were analyzed using linear regressions and the mediation analysis models. RESULTS Compared to the control group, the newborns in the depressed group had lower scores in the social-interaction and autonomic system dimensions of NBAS (P < 0.01). Maternal and umbilical cord plasma cortisol levels in the depressed group were higher (P < 0.01) than in the control group. However, only umbilical cord plasma cortisol played a negative mediating role in the relationship between maternal EPDS and NBAS in the social-interaction and autonomic system (β med = -0.054 [-0.115,-0.018] and -0.052 [-0.105,-0.019]. Proportional mediation was 13.57 % and 12.33 for social-interaction and autonomic systems, respectively. The newborns in the depressed group showed decreases in the strength of rs-fNIRS functional connections, primarily the connectivity of the left frontal-parietal and temporal-parietal regions. However, infants in the depressed and control groups showed no differences in topological characteristics of the brain network, including standardized clustering coefficient, characteristic path length, small-world property, global efficiency, and local efficiency (P > 0.05). The social-interaction Z-scores had positive correlations with functional connectivity strength of left prefrontal cortex-left parietal lobe (r = 0.57, p < 0.01),prefrontal cortex-left parietal lobe - left temporal lobe (r = 0.593, p < 0.01) and left parietal lobe - left temporal lobe (r = 0.498, p < 0.01). Autonomic system Z-scores were also significantly positive correlation with prefrontal cortex-left parietal lobe (r = 0.509, p < 0.01),prefrontal cortex-left parietal lobe - left temporal lobe (r = 0.464, p < 0.01), left parietal lobe - left temporal lobe (r = 0.381, p < 0.05), and right temporal lobe and left temporal lobe (r = 0.310, p < 0.05). CONCLUSION This study shows that maternal prenatal depression may affect the development of neonatal social-interaction and autonomic system and the strength of neonatal brain functional connectivity. The fetal cortisol may play a role in behavioral development in infants exposed to maternal prenatal depression. Our findings highlight the importance of prenatal screening for maternal depression and early postnatal behavioral evaluation that provide the opportunity for early diagnosis and intervention to improve neurodevelopmental outcomes.
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Affiliation(s)
- Shan Wang
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Neonatology, the Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Chenxi Ding
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Chengyin Dou
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Zeen Zhu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Dan Zhang
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Qiqi Yi
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Haoyue Wu
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Longshan Xie
- Department of Functional Neuroscience, The First People's Hospital of Foshan (The Affiliated Foshan Hospital of Sun Yat -sen University), Guangdong, China
| | - Zhongliang Zhu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Maternal and Infant Health Research Institute and Medical College, Northwestern University, Xi'an, China
| | - Dongli Song
- Division of Neonatology, Department of Pediatrics, Santa Clara Valley Medical Center, San Jose, CA, USA.
| | - Hui Li
- Department of Neonatology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Neonatology, the Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, China.
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Srakočić S, Josić P, Trifunović S, Gajović S, Grčević D, Glasnović A. Proposed practical protocol for flow cytometry analysis of microglia from the healthy adult mouse brain: Systematic review and isolation methods’ evaluation. Front Cell Neurosci 2022; 16:1017976. [PMID: 36339814 PMCID: PMC9626753 DOI: 10.3389/fncel.2022.1017976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/05/2022] [Indexed: 11/25/2022] Open
Abstract
The aim of our study was to systematically analyze the literature for published flow cytometry protocols for microglia isolation and compare their effectiveness in terms of microglial yield, including our own protocol using sucrose for myelin removal and accutase for enzymatic digestion. For systematic review, the PubMed was searched for the terms “flow cytometry,” “microglia,” “brain,” and “mice.” Three different myelin removal methods (Percoll, sucrose, and no removal) and five protocols for enzymatic digestion (accutase, dispase II, papain, trypsin, and no enzymatic digestion) were tested for the effectiveness of microglia (CD11b+CD45int cell population) isolation from the adult mouse brain using flow cytometry. Qualitative analysis of the 32 selected studies identified three most commonly used myelin removal protocols: Percoll, the use of myelin removal kit, and no removal. Nine enzymatic digestion protocols were identified, from which we selected dispase II, papain, trypsin, and no enzymatic digestion. A comparison of these myelin removal methods and digestion protocols showed the Percoll method to be preferable in removal of non-immune cells, and superior to the use of sucrose which was less effective in removal of non-immune cells, but resulted in a comparable microglial yield to Percoll myelin removal. Digestion with accutase resulted in one of the highest microglial yields, all while having the lowest variance among tested protocols. The proposed protocol for microglia isolation uses Percoll for myelin removal and accutase for enzymatic digestion. All tested protocols had different features, and the choice between them can depend on the individual focus of the research.
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10
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Auguste YSS, Ferro A, Kahng JA, Xavier AM, Dixon JR, Vrudhula U, Nichitiu AS, Rosado D, Wee TL, Pedmale UV, Cheadle L. Oligodendrocyte precursor cells engulf synapses during circuit remodeling in mice. Nat Neurosci 2022; 25:1273-1278. [PMID: 36171430 PMCID: PMC9534756 DOI: 10.1038/s41593-022-01170-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 08/18/2022] [Indexed: 01/13/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes throughout life, but the functions of OPCs are not limited to oligodendrogenesis. Here we show that OPCs contribute to thalamocortical presynapse elimination in the developing and adult mouse visual cortex. OPC-mediated synapse engulfment increases in response to sensory experience during neural circuit refinement. Our data suggest that OPCs may regulate synaptic connectivity in the brain independently of oligodendrogenesis.
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Affiliation(s)
| | - Austin Ferro
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Jessica A Kahng
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.,School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Andre M Xavier
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Uma Vrudhula
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Daniele Rosado
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Tse-Luen Wee
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Lucas Cheadle
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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11
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Garcia G, Fernandes A, Stein F, Brites D. Protective Signature of IFNγ-Stimulated Microglia Relies on miR-124-3p Regulation From the Secretome Released by Mutant APP Swedish Neuronal Cells. Front Pharmacol 2022; 13:833066. [PMID: 35620289 PMCID: PMC9127204 DOI: 10.3389/fphar.2022.833066] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/25/2022] [Indexed: 12/19/2022] Open
Abstract
Microglia-associated inflammation and miRNA dysregulation are key players in Alzheimer’s disease (AD) pathophysiology. Previously, we showed miR-124 upregulation in APP Swedish SH-SY5Y (SWE) and PSEN1 iPSC-derived neurons and its propagation by the secretome (soluble and exosomal fractions). After modulation with miR-124 mimic/inhibitor, we identified common responsive mechanisms between such models. We also reported miR-124 colocalization with microglia in AD patient hippocampi. Herein, we determined how miR-124 modulation in SWE cells influences microglia polarized subtypes in the context of inflammation. We used a coculture system without cell-to-cell contact formed by miR-124 modulated SWE cells and human CHME3 microglia stimulated with interferon-gamma (IFNγ-MG), in which we assessed their adopted gene/miRNA profile and proteomic signature. The increase of miR-124 in SWE cells/secretome (soluble and exosomal) was mimicked in IFNγ-MG. Treatment of SWE cells with the miR-124 inhibitor led to RAGE overexpression and loss of neuronal viability, while the mimic caused RAGE/HMGB1 downregulation and prevented mitochondria membrane potential loss. When accessing the paracrine effects on microglia, SWE miR-124 inhibitor favored their IFNγ-induced inflammatory signature (upregulated RAGE/HMGB1/iNOS/IL-1β; downregulated IL-10/ARG-1), while the mimic reduced microglia activation (downregulated TNF-α/iNOS) and deactivated extracellular MMP-2/MMP-9 levels. Microglia proteomics identified 113 responsive proteins to SWE miR-124 levels, including a subgroup of 17 proteins involved in immune function/inflammation and/or miR-124 targets. A total of 72 proteins were downregulated (e.g., MAP2K6) and 21 upregulated (e.g., PAWR) by the mimic, while the inhibitor also upregulated 21 proteins and downregulated 17 (e.g., TGFB1, PAWR, and EFEMP1). Other targets were associated with neurodevelopmental mechanisms, synaptic function, and vesicular trafficking. To examine the source of miR-124 variations in microglia, we silenced the RNase III endonuclease Dicer1 to block miRNA canonical biogenesis. Despite this suppression, the coculture with SWE cells/exosomes still raised microglial miR-124 levels, evidencing miR-124 transfer from neurons to microglia. This study is pioneer in elucidating that neuronal miR-124 reshapes microglia plasticity and in revealing the relevance of neuronal survival in mechanisms underlying inflammation in AD-associated neurodegeneration. These novel insights pave the way for the application of miRNA-based neuropharmacological strategies in AD whenever miRNA dysregulated levels are identified during patient stratification.
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Affiliation(s)
- Gonçalo Garcia
- Neuroinflammation, Signaling and Neuroregeneration Laboratory, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.,Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Adelaide Fernandes
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.,Central Nervous System, Blood and Peripheral Inflammation, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Frank Stein
- Proteomics Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Dora Brites
- Neuroinflammation, Signaling and Neuroregeneration Laboratory, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
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12
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Serrano ME, Kim E, Petrinovic MM, Turkheimer F, Cash D. Imaging Synaptic Density: The Next Holy Grail of Neuroscience? Front Neurosci 2022; 16:796129. [PMID: 35401097 PMCID: PMC8990757 DOI: 10.3389/fnins.2022.796129] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/15/2022] [Indexed: 12/19/2022] Open
Abstract
The brain is the central and most complex organ in the nervous system, comprising billions of neurons that constantly communicate through trillions of connections called synapses. Despite being formed mainly during prenatal and early postnatal development, synapses are continually refined and eliminated throughout life via complicated and hitherto incompletely understood mechanisms. Failure to correctly regulate the numbers and distribution of synapses has been associated with many neurological and psychiatric disorders, including autism, epilepsy, Alzheimer’s disease, and schizophrenia. Therefore, measurements of brain synaptic density, as well as early detection of synaptic dysfunction, are essential for understanding normal and abnormal brain development. To date, multiple synaptic density markers have been proposed and investigated in experimental models of brain disorders. The majority of the gold standard methodologies (e.g., electron microscopy or immunohistochemistry) visualize synapses or measure changes in pre- and postsynaptic proteins ex vivo. However, the invasive nature of these classic methodologies precludes their use in living organisms. The recent development of positron emission tomography (PET) tracers [such as (18F)UCB-H or (11C)UCB-J] that bind to a putative synaptic density marker, the synaptic vesicle 2A (SV2A) protein, is heralding a likely paradigm shift in detecting synaptic alterations in patients. Despite their limited specificity, novel, non-invasive magnetic resonance (MR)-based methods also show promise in inferring synaptic information by linking to glutamate neurotransmission. Although promising, all these methods entail various advantages and limitations that must be addressed before becoming part of routine clinical practice. In this review, we summarize and discuss current ex vivo and in vivo methods of quantifying synaptic density, including an evaluation of their reliability and experimental utility. We conclude with a critical assessment of challenges that need to be overcome before successfully employing synaptic density biomarkers as diagnostic and/or prognostic tools in the study of neurological and neuropsychiatric disorders.
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Affiliation(s)
- Maria Elisa Serrano
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Eugene Kim
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Marija M Petrinovic
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
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13
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Rosmus DD, Lange C, Ludwig F, Ajami B, Wieghofer P. The Role of Osteopontin in Microglia Biology: Current Concepts and Future Perspectives. Biomedicines 2022; 10:biomedicines10040840. [PMID: 35453590 PMCID: PMC9027630 DOI: 10.3390/biomedicines10040840] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 12/14/2022] Open
Abstract
The innate immune landscape of the central nervous system (CNS), including the brain and the retina, consists of different myeloid cell populations with distinct tasks to fulfill. Whereas the CNS borders harbor extraparenchymal CNS-associated macrophages whose main duty is to build up a defense against invading pathogens and other damaging factors from the periphery, the resident immune cells of the CNS parenchyma and the retina, microglia, are highly dynamic cells with a plethora of functions during homeostasis and disease. Therefore, microglia are constantly sensing their environment and closely interacting with surrounding cells, which is in part mediated by soluble factors. One of these factors is Osteopontin (OPN), a multifunctional protein that is produced by different cell types in the CNS, including microglia, and is upregulated in neurodegenerative and neuroinflammatory conditions. In this review, we discuss the current literature about the interaction between microglia and OPN in homeostasis and several disease entities, including multiple sclerosis (MS), Alzheimer’s and cerebrovascular diseases (AD, CVD), amyotrophic lateral sclerosis (ALS), age-related macular degeneration (AMD) and diabetic retinopathy (DR), in the context of the molecular pathways involved in OPN signaling shaping the function of microglia. As nearly all CNS diseases are characterized by pathological alterations in microglial cells, accompanied by the disturbance of the homeostatic microglia phenotype, the emergence of disease-associated microglia (DAM) states and their interplay with factors shaping the DAM-signature, such as OPN, is of great interest for therapeutical interventions in the future.
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Affiliation(s)
| | - Clemens Lange
- Eye Center, Freiburg Medical Center, University of Freiburg, 79106 Freiburg, Germany; (C.L.); (F.L.)
- Ophtha-Lab, Department of Ophthalmology, St. Franziskus Hospital, 48145 Muenster, Germany
| | - Franziska Ludwig
- Eye Center, Freiburg Medical Center, University of Freiburg, 79106 Freiburg, Germany; (C.L.); (F.L.)
| | - Bahareh Ajami
- Department of Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA;
| | - Peter Wieghofer
- Institute of Anatomy, Leipzig University, 04103 Leipzig, Germany;
- Cellular Neuroanatomy, Institute of Theoretical Medicine, Medical Faculty, Augsburg University, 86159 Augsburg, Germany
- Correspondence:
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14
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Differential Expression Patterns of TDP-43 in Single Moderate versus Repetitive Mild Traumatic Brain Injury in Mice. Int J Mol Sci 2021; 22:ijms222212211. [PMID: 34830093 PMCID: PMC8621440 DOI: 10.3390/ijms222212211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/31/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Traumatic brain injury (TBI) is a disabling disorder and a major cause of death and disability in the world. Both single and repetitive traumas affect the brain acutely but can also lead to chronic neurodegenerative changes. Clinical studies have shown some dissimilarities in transactive response DNA binding protein 43 (TDP-43) expression patterns following single versus repetitive TBI. We explored the acute cortical post-traumatic changes of TDP-43 using the lateral fluid percussion injury (LFPI) model of single moderate TBI in adult male mice and investigated the association of TDP-43 with post-traumatic neuroinflammation and synaptic plasticity. In the ipsilateral cortices of animals following LFPI, we found changes in the cytoplasmic and nuclear levels of TDP-43 and the decreased expression of postsynaptic protein 95 within the first 3 d post-injury. Subacute pathological changes of TDP-43 in the hippocampi of animals following LFPI and in mice exposed to repetitive mild TBI (rmTBI) were studied. Changes in the hippocampal TDP-43 expression patterns at 14 d following different brain trauma procedures showed pathological alterations only after single moderate, but not following rmTBI. Hippocampal LFPI-induced TDP-43 pathology was not accompanied by the microglial reaction, contrary to the findings after rmTBI, suggesting that different types of brain trauma may cause diverse pathophysiological changes in the brain, specifically related to the TDP-43 protein as well as to the microglial reaction. Taken together, our findings may contribute to a better understanding of the pathophysiological events following brain trauma.
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15
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Cornell J, Salinas S, Huang HY, Zhou M. Microglia regulation of synaptic plasticity and learning and memory. Neural Regen Res 2021; 17:705-716. [PMID: 34472455 PMCID: PMC8530121 DOI: 10.4103/1673-5374.322423] [Citation(s) in RCA: 157] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microglia are the resident macrophages of the central nervous system. Microglia possess varied morphologies and functions. Under normal physiological conditions, microglia mainly exist in a resting state and constantly monitor their microenvironment and survey neuronal and synaptic activity. Through the C1q, C3 and CR3 “Eat Me” and CD47 and SIRPα “Don’t Eat Me” complement pathways, as well as other pathways such as CX3CR1 signaling, resting microglia regulate synaptic pruning, a process crucial for the promotion of synapse formation and the regulation of neuronal activity and synaptic plasticity. By mediating synaptic pruning, resting microglia play an important role in the regulation of experience-dependent plasticity in the barrel cortex and visual cortex after whisker removal or monocular deprivation, and also in the regulation of learning and memory, including the modulation of memory strength, forgetfulness, and memory quality. As a response to brain injury, infection or neuroinflammation, microglia become activated and increase in number. Activated microglia change to an amoeboid shape, migrate to sites of inflammation and secrete proteins such as cytokines, chemokines and reactive oxygen species. These molecules released by microglia can lead to synaptic plasticity and learning and memory deficits associated with aging, Alzheimer’s disease, traumatic brain injury, HIV-associated neurocognitive disorder, and other neurological or mental disorders such as autism, depression and post-traumatic stress disorder. With a focus mainly on recently published literature, here we reviewed the studies investigating the role of resting microglia in synaptic plasticity and learning and memory, as well as how activated microglia modulate disease-related plasticity and learning and memory deficits. By summarizing the function of microglia in these processes, we aim to provide an overview of microglia regulation of synaptic plasticity and learning and memory, and to discuss the possibility of microglia manipulation as a therapeutic to ameliorate cognitive deficits associated with aging, Alzheimer’s disease, traumatic brain injury, HIV-associated neurocognitive disorder, and mental disorders.
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Affiliation(s)
- Jessica Cornell
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Shelbi Salinas
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Hou-Yuan Huang
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Miou Zhou
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
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16
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Cohn W, Melnik M, Huang C, Teter B, Chandra S, Zhu C, McIntire LB, John V, Gylys KH, Bilousova T. Multi-Omics Analysis of Microglial Extracellular Vesicles From Human Alzheimer's Disease Brain Tissue Reveals Disease-Associated Signatures. Front Pharmacol 2021; 12:766082. [PMID: 34925024 PMCID: PMC8675946 DOI: 10.3389/fphar.2021.766082] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 10/19/2021] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, yet there is no cure or diagnostics available prior to the onset of clinical symptoms. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are released from almost all types of cell. Genome-wide association studies have linked multiple AD genetic risk factors to microglia-specific pathways. It is plausible that microglia-derived EVs may play a role in the progression of AD by contributing to the dissemination of insoluble pathogenic proteins, such as tau and Aβ. Despite the potential utility of EVs as a diagnostic tool, our knowledge of human brain EV subpopulations is limited. Here we present a method for isolating microglial CD11b-positive small EVs from cryopreserved human brain tissue, as well as an integrated multiomics analysis of microglial EVs enriched from the parietal cortex of four late-stage AD (Braak V-VI) and three age-matched normal/low pathology (NL) cases. This integrated analysis revealed 1,000 proteins, 594 lipids, and 105 miRNAs using shotgun proteomics, targeted lipidomics, and NanoString nCounter technology, respectively. The results showed a significant reduction in the abundance of homeostatic microglia markers P2RY12 and TMEM119, and increased levels of disease-associated microglia markers FTH1 and TREM2, in CD11b-positive EVs from AD brain compared to NL cases. Tau abundance was significantly higher in AD brain-derived microglial EVs. These changes were accompanied by the upregulation of synaptic and neuron-specific proteins in the AD group. Levels of free cholesterol were elevated in microglial EVs from the AD brain. Lipidomic analysis also revealed a proinflammatory lipid profile, endolysosomal dysfunction, and a significant AD-associated decrease in levels of docosahexaenoic acid (DHA)-containing polyunsaturated lipids, suggesting a potential defect in acyl-chain remodeling. Additionally, four miRNAs associated with immune and cellular senescence signaling pathways were significantly upregulated in the AD group. Our data suggest that loss of the homeostatic microglia signature in late AD stages may be accompanied by endolysosomal impairment and the release of undigested neuronal and myelin debris, including tau, through extracellular vesicles. We suggest that the analysis of microglia-derived EVs has merit for identifying novel EV-associated biomarkers and providing a framework for future larger-scale multiomics studies on patient-derived cell-type-specific EVs.
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Affiliation(s)
- Whitaker Cohn
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Mikhail Melnik
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Calvin Huang
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bruce Teter
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Sujyoti Chandra
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Chunni Zhu
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Laura Beth McIntire
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Varghese John
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Karen H Gylys
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Tina Bilousova
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States.,School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
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