1
|
Zhao S, Umpierre AD, Wu LJ. Tuning neural circuits and behaviors by microglia in the adult brain. Trends Neurosci 2024; 47:181-194. [PMID: 38245380 PMCID: PMC10939815 DOI: 10.1016/j.tins.2023.12.003] [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: 07/07/2023] [Revised: 11/04/2023] [Accepted: 12/21/2023] [Indexed: 01/22/2024]
Abstract
Microglia are the primary immune cells of the CNS, contributing to both inflammatory damage and tissue repair in neurological disorder. In addition, emerging evidence highlights the role of homeostatic microglia in regulating neuronal activity, interacting with synapses, tuning neural circuits, and modulating behaviors. Herein, we review how microglia sense and regulate neuronal activity through synaptic interactions, thereby directly engaging with neural networks and behaviors. We discuss current studies utilizing microglial optogenetic and chemogenetic approaches to modulate adult neural circuits. These manipulations of microglia across different CNS regions lead to diverse behavioral consequences. We propose that spatial heterogeneity of microglia-neuron interaction lays the groundwork for understanding diverse functions of microglia in neural circuits and behaviors.
Collapse
Affiliation(s)
- Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | | | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Department of Immunology, Mayo Clinic, Rochester, MN, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
| |
Collapse
|
2
|
Hu Y, Tao W. Current perspectives on microglia-neuron communication in the central nervous system: Direct and indirect modes of interaction. J Adv Res 2024:S2090-1232(24)00006-7. [PMID: 38195039 DOI: 10.1016/j.jare.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 10/05/2023] [Accepted: 01/06/2024] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND The incessant communication that takes place between microglia and neurons is essential the development, maintenance, and pathogenesis of the central nervous system (CNS). As mobile phagocytic cells, microglia serve a critical role in surveilling and scavenging the neuronal milieu to uphold homeostasis. AIM OF REVIEW This review aims to discuss the various mechanisms that govern the interaction between microglia and neurons, from the molecular to the organ system level, and to highlight the importance of these interactions in the development, maintenance, and pathogenesis of the CNS. KEY SCIENTIFIC CONCEPTS OF REVIEW Recent research has revealed that microglia-neuron interaction is vital for regulating fundamental neuronal functions, such as synaptic pruning, axonal remodeling, and neurogenesis. The review will elucidate the intricate signaling pathways involved in these interactions, both direct and indirect, to provide a better understanding of the fundamental mechanisms of brain function. Furthermore, gaining insights into these signals could lead to the development of innovative therapies for neural disorders.
Collapse
Affiliation(s)
- Yue Hu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 220023, China; School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Weiwei Tao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, and National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing 220023, China; School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| |
Collapse
|
3
|
Bedolla A, Wegman E, Weed M, Paranjpe A, Alkhimovitch A, Ifergan I, McClain L, Luo Y. Microglia-derived TGF-β1 ligand maintains microglia homeostasis via autocrine mechanism and is critical for normal cognitive function in adult mouse brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.05.547814. [PMID: 37461569 PMCID: PMC10349967 DOI: 10.1101/2023.07.05.547814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
While TGF-β signaling is essential for microglial function, the cellular source of TGF-β ligand and its spatial regulation remains unclear in the adult CNS. Our data support that microglia, not astrocytes or neurons, are the primary producers of TGF-β1 ligands needed for microglial homeostasis. Microglia (MG)-Tgfb1 inducible knockout (iKO) leads to the activation of microglia featuring a dyshomeostatic transcriptomic profile that resembles disease-associated microglia (DAMs), injury-associated microglia, and aged microglia, suggesting that microglial self-produced TGF-β1 ligands are important in the adult CNS. Interestingly, astrocytes in MG-Tgfb1 iKO mice show a transcriptome profile that closely aligns with A1-like astrocytes. Additionally, using sparse mosaic single-cell microglia iKO of TGF-β1 ligand, we established an autocrine mechanism for TGF-β signaling. Importantly MG-Tgfb1 iKO mice show cognitive deficits, supporting that precise spatial regulation of TGF-β1 ligand derived from microglia is critical for the maintenance of brain homeostasis and normal cognitive function in the adult brain.
Collapse
Affiliation(s)
- Alicia Bedolla
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Elliot Wegman
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Max Weed
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Aditi Paranjpe
- Information Services, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Anastasia Alkhimovitch
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Igal Ifergan
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45229, USA
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Lucas McClain
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Yu Luo
- Department of Molecular and Cellular Biosciences, University of Cincinnati, Cincinnati, OH 45229, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45229, USA
| |
Collapse
|
4
|
Petry P, Oschwald A, Kierdorf K. Microglial tissue surveillance: The never-resting gardener in the developing and adult CNS. Eur J Immunol 2023; 53:e2250232. [PMID: 37042800 DOI: 10.1002/eji.202250232] [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: 12/28/2022] [Revised: 03/24/2023] [Accepted: 04/11/2023] [Indexed: 04/13/2023]
Abstract
Immunosurveillance by microglia is a dynamic process in the central nervous system (CNS) with versatile functions to maintain tissue homeostasis and provide immune defense. A tightly controlled microglia network throughout the CNS parenchyma facilitates efficient immunosurveillance, where each cell guards a certain tissue territory. Each cell is constantly surveilling its environment and the surrounding cells, screening for pathogens but also removing cell debris and metabolites, grooming neighboring cells and facilitating cellular crosstalk. In the absence of inflammation, this "tissue surveillance" by microglia presents an essential process for CNS homeostasis and development. In this review, we provide a summary on different tissue surveillance functions mediated by microglia, the underlying molecular machineries, and how defects, such as genetic mutations, can alter these surveillance mechanisms and cause disease onset.
Collapse
Affiliation(s)
- Philippe Petry
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Alexander Oschwald
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| |
Collapse
|
5
|
Schwabenland M, Mossad O, Sievert A, Peres AG, Ringel E, Baasch S, Kolter J, Cascone G, Dokalis N, Vlachos A, Ruzsics Z, Henneke P, Prinz M, Blank T. Neonatal immune challenge poses a sex-specific risk for epigenetic microglial reprogramming and behavioral impairment. Nat Commun 2023; 14:2721. [PMID: 37169749 PMCID: PMC10175500 DOI: 10.1038/s41467-023-38373-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
While the precise processes underlying a sex bias in the development of central nervous system (CNS) disorders are unknown, there is growing evidence that an early life immune activation can contribute to the disease pathogenesis. When we mimicked an early systemic viral infection or applied murine cytomegalovirus (MCMV) systemically in neonatal female and male mice, only male adolescent mice presented behavioral deficits, including reduced social behavior and cognition. This was paralleled by an increased amount of infiltrating T cells in the brain parenchyma, enhanced interferon-γ (IFNγ) signaling, and epigenetic reprogramming of microglial cells. These microglial cells showed increased phagocytic activity, which resulted in abnormal loss of excitatory synapses within the hippocampal brain region. None of these alterations were seen in female adolescent mice. Our findings underscore the early postnatal period's susceptibility to cause sex-dependent long-term CNS deficiencies following infections.
Collapse
Affiliation(s)
- Marius Schwabenland
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Omar Mossad
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Annika Sievert
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Adam G Peres
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Elena Ringel
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian Baasch
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Kolter
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Giulia Cascone
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nikolaos Dokalis
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Zsolt Ruzsics
- Institute for Virology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Philipp Henneke
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Pediatrics and Adolescent Medicine, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Thomas Blank
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| |
Collapse
|
6
|
Elzinga SE, Koubek EJ, Hayes JM, Carter A, Mendelson FE, Webber-Davis I, Lentz SI, Feldman EL. Modeling the innate inflammatory cGAS/STING pathway: sexually dimorphic effects on microglia and cognition in obesity and prediabetes. Front Cell Neurosci 2023; 17:1167688. [PMID: 37206668 PMCID: PMC10188944 DOI: 10.3389/fncel.2023.1167688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/06/2023] [Indexed: 05/21/2023] Open
Abstract
Introduction The prevalence of obesity, prediabetes, and diabetes continues to grow worldwide. These metabolic dysfunctions predispose individuals to neurodegenerative diseases and cognitive impairment, including dementias such as Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD). The innate inflammatory cGAS/STING pathway plays a pivotal role in metabolic dysfunction and is an emerging target of interest in multiple neurodegenerative diseases, including AD/ADRD. Therefore, our goal was to establish a murine model to specifically target the cGAS/STING pathway to study obesity- and prediabetes-induced cognitive impairment. Methods We performed two pilot studies in cGAS knockout (cGAS-/-) male and female mice designed to characterize basic metabolic and inflammatory phenotypes and examine the impact of high-fat diet (HFD) on metabolic, inflammatory, and cognitive parameters. Results cGAS-/- mice displayed normal metabolic profiles and retained the ability to respond to inflammatory stimuli, as indicated by an increase in plasma inflammatory cytokine production in response to lipopolysaccharide injection. HFD feeding caused expected increases in body weight and decreases in glucose tolerance, although onset was accelerated in females versus males. While HFD did not increase plasma or hippocampal inflammatory cytokine production, it did alter microglial morphology to a state indicative of activation, particularly in female cGAS-/- mice. However, HFD negatively impacted cognitive outcomes in male, but not female animals. Discussion Collectively, these results suggest that cGAS-/- mice display sexually dimorphic responses to HFD, possibly based on differences in microglial morphology and cognition.
Collapse
Affiliation(s)
- Sarah E. Elzinga
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Emily J. Koubek
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - John M. Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - A. Carter
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Faye E. Mendelson
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Ian Webber-Davis
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Stephen I. Lentz
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| |
Collapse
|
7
|
The Dialogue Between Neuroinflammation and Adult Neurogenesis: Mechanisms Involved and Alterations in Neurological Diseases. Mol Neurobiol 2023; 60:923-959. [PMID: 36383328 DOI: 10.1007/s12035-022-03102-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/23/2022] [Indexed: 11/18/2022]
Abstract
Adult neurogenesis occurs mainly in the subgranular zone of the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles. Evidence supports the critical role of adult neurogenesis in various conditions, including cognitive dysfunction, Alzheimer's disease (AD), and Parkinson's disease (PD). Several factors can alter adult neurogenesis, including genetic, epigenetic, age, physical activity, diet, sleep status, sex hormones, and central nervous system (CNS) disorders, exerting either pro-neurogenic or anti-neurogenic effects. Compelling evidence suggests that any insult or injury to the CNS, such as traumatic brain injury (TBI), infectious diseases, or neurodegenerative disorders, can provoke an inflammatory response in the CNS. This inflammation could either promote or inhibit neurogenesis, depending on various factors, such as chronicity and severity of the inflammation and underlying neurological disorders. Notably, neuroinflammation, driven by different immune components such as activated glia, cytokines, chemokines, and reactive oxygen species, can regulate every step of adult neurogenesis, including cell proliferation, differentiation, migration, survival of newborn neurons, maturation, synaptogenesis, and neuritogenesis. Therefore, this review aims to present recent findings regarding the effects of various components of the immune system on adult neurogenesis and to provide a better understanding of the role of neuroinflammation and neurogenesis in the context of neurological disorders, including AD, PD, ischemic stroke (IS), seizure/epilepsy, TBI, sleep deprivation, cognitive impairment, and anxiety- and depressive-like behaviors. For each disorder, some of the most recent therapeutic candidates, such as curcumin, ginseng, astragaloside, boswellic acids, andrographolide, caffeine, royal jelly, estrogen, metformin, and minocycline, have been discussed based on the available preclinical and clinical evidence.
Collapse
|
8
|
Fractalkine/CX3CR1-Dependent Modulation of Synaptic and Network Plasticity in Health and Disease. Neural Plast 2023; 2023:4637073. [PMID: 36644710 PMCID: PMC9833910 DOI: 10.1155/2023/4637073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 01/06/2023] Open
Abstract
CX3CR1 is a G protein-coupled receptor that is expressed exclusively by microglia within the brain parenchyma. The only known physiological CX3CR1 ligand is the chemokine fractalkine (FKN), which is constitutively expressed in neuronal cell membranes and tonically released by them. Through its key role in microglia-neuron communication, the FKN/CX3CR1 axis regulates microglial state, neuronal survival, synaptic plasticity, and a variety of synaptic functions, as well as neuronal excitability via cytokine release modulation, chemotaxis, and phagocytosis. Thus, the absence of CX3CR1 or any failure in the FKN/CX3CR1 axis has been linked to alterations in different brain functions, including changes in synaptic and network plasticity in structures such as the hippocampus, cortex, brainstem, and spinal cord. Since synaptic plasticity is a basic phenomenon in neural circuit integration and adjustment, here, we will review its modulation by the FKN/CX3CR1 axis in diverse brain circuits and its impact on brain function and adaptation in health and disease.
Collapse
|
9
|
Galea E, Graeber MB. Neuroinflammation: The Abused Concept. ASN Neuro 2023; 15:17590914231197523. [PMID: 37647500 PMCID: PMC10469255 DOI: 10.1177/17590914231197523] [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: 07/31/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Scientific progress requires the relentless correction of errors and refinement of hypotheses. Clarity of terminology is essential for clarity of thought and proper experimental interrogation of nature. Therefore, the application of the same scientific term to different and even conflicting phenomena and concepts is not useful and must be corrected. Such abuse of terminology has happened and is still increasing in the case of "neuroinflammation," a term that until the 1990s meant classical inflammation affecting the central nervous system (CNS) and thereon was progressively used to mostly denote microglia activation. The resulting confusion is very wasteful and detrimental not only for scientists but also for patients, given the numerous failed clinical trials in acute and chronic CNS diseases over the last decade with "anti-inflammatory" drugs. Despite this failure, reassessments of the "neuroinflammation" concept are rare, especially considering the number of articles still using the term. This undesirable situation motivates this article. We review the origins and evolution of the term "neuroinflammation," discuss the unique tissue defense and repair strategies in the CNS, define CNS immunity, and emphasize the notion of gliopathies to help readdress, if not bury, the term "neuroinflammation" as it stands in the way of scientific progress.
Collapse
Affiliation(s)
- Elena Galea
- Departament de Bioquímica, Unitat de Bioquímica, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
- ICREA, Barcelona, Spain
| | - Manuel B. Graeber
- Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Camperdown, Australia
| |
Collapse
|
10
|
Ren M, Zhang J, Dai S, Wang C, Chen Z, Zhang S, Xu J, Qin X, Liu F. CX3CR1 deficiency exacerbates immune-mediated hepatitis by increasing NF-κB-mediated cytokine production in macrophage and T cell. Exp Biol Med (Maywood) 2023; 248:117-129. [PMID: 36426712 PMCID: PMC10041049 DOI: 10.1177/15353702221128573] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Immune-mediated hepatitis is marked by liver inflammation characterized by immune cell infiltration, chemokine/cytokine production, and hepatocyte injury. C-X3C motif receptor 1 (CX3CR1), as the receptor of chemokine C-X3C motif ligand 1 (CX3CL1)/fractalkine, is mainly expressed on immune cells including monocytes and T cells. Previous studies have shown that CX3CR1 protects against liver fibrosis, but the exact role of CX3CL1/CX3CR1 in acute immune-mediated hepatitis remains unknown. Here, we investigate the role of the CX3CL1/CX3CR1 axis in immune-mediated hepatitis using concanavalin A (ConA)-induced liver injury model in CX3CR1-deficient (Cx3cr1-/-) mice. We observed that Cx3cr1-/- mice had severe liver injury and increased pro-inflammatory cytokines (tumor necrosis factor-alpha [TNF-α], interferon-gamma [IFN-γ], interleukin-1 beta [IL-1β], and IL-6) in serum and liver compared to wild-type (Cx3cr1+/+) mice after ConA injection. The deficiency of CX3CR1 did not affect ConA-induced immune cell infiltration in liver but led to elevated production of TNF-α in macrophages as well as IFN-γ in T cells after ConA treatment. On the contrary, exogenous CX3CL1 attenuated ConA-induced cytokine production in wild type, but not CX3CR1-deficient macrophages and T cells. Furthermore, in vitro results showed that CX3CR1 deficiency promoted the pro-inflammatory cytokine expression by increasing the phosphorylation of nuclear factor kappa B (NF-κB) p65 (p-NF-κB p65). Finally, pre-treatment of p-NF-κB p65 inhibitor, resveratrol, attenuated ConA-induced liver injury and inflammatory responses, especially in Cx3cr1-/- mice. In conclusion, our data show that the deficiency of CX3CR1 promotes pro-inflammatory cytokine production in macrophages and T cells by enhancing the phosphorylation of NF-κB p65, which exacerbates liver injury in ConA-induced hepatitis.
Collapse
Affiliation(s)
- Mi Ren
- Department of Hepatobiliary Surgery and Liver Transplantation, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, People's Republic of China
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Jinyan Zhang
- Department of Hepatobiliary Surgery and Liver Transplantation, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, People's Republic of China
| | - Shen Dai
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA
- Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250000, People's Republic of China
| | - Chenxiao Wang
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Zheng Chen
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Siqi Zhang
- Department of Hepatobiliary Surgery and Liver Transplantation, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, People's Republic of China
| | - Junming Xu
- Department of Hepatobiliary Surgery and Liver Transplantation, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, People's Republic of China
| | - Xuebin Qin
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Fengming Liu
- Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250000, People's Republic of China
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| |
Collapse
|
11
|
Honey D, Wosnitzka E, Klann E, Weinhard L. Analysis of microglial BDNF function and expression in the motor cortex. Front Cell Neurosci 2022; 16:961276. [PMID: 36726454 PMCID: PMC9885322 DOI: 10.3389/fncel.2022.961276] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 11/07/2022] [Indexed: 12/25/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is a neurotrophin that regulates several aspects of brain function. Although numerous studies have demonstrated the expression and function of BDNF in neurons, its expression in microglia remains controversial. Using a combination of genetic tools and fluorescence imaging, we analyzed BDNF expression patterns and investigated the effect of microglial Bdnf deletion on neuronal activity, early-stage spine formation, and microglia-neuron attraction in the motor cortex. We did not detect BDNF expression in microglia at the transcriptional or translational level, in physiological or pathological conditions, and none of the assessed neuronal functions were found to be affected in conditional Bdnf knockout mice. Our results suggest that microglia do not express BDNF in sufficient amounts to modulate neuronal function.
Collapse
Affiliation(s)
- Diana Honey
- NYU Grossman School of Medicine, New York, NY, United States,Center for Neural Science, New York University, New York, NY, United States
| | - Erin Wosnitzka
- Department of Fundamental Neurosciences, UNIL, Lausanne, Switzerland,Cardiff School of Biosciences, Cardiff University, Wales, United Kingdom
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, United States
| | - Laetitia Weinhard
- NYU Grossman School of Medicine, New York, NY, United States,*Correspondence: Laetitia Weinhard
| |
Collapse
|
12
|
Cserép C, Schwarcz AD, Pósfai B, László ZI, Kellermayer A, Környei Z, Kisfali M, Nyerges M, Lele Z, Katona I, Ádám Dénes. Microglial control of neuronal development via somatic purinergic junctions. Cell Rep 2022; 40:111369. [PMID: 36130488 PMCID: PMC9513806 DOI: 10.1016/j.celrep.2022.111369] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/28/2022] [Accepted: 08/25/2022] [Indexed: 11/30/2022] Open
Abstract
Microglia, the resident immune cells of the brain, play important roles during development. Although bi-directional communication between microglia and neuronal progenitors or immature neurons has been demonstrated, the main sites of interaction and the underlying mechanisms remain elusive. By using advanced methods, here we provide evidence that microglial processes form specialized contacts with the cell bodies of developing neurons throughout embryonic, early postnatal, and adult neurogenesis. These early developmental contacts are highly reminiscent of somatic purinergic junctions that are instrumental for microglia-neuron communication in the adult brain. The formation and maintenance of these junctions is regulated by functional microglial P2Y12 receptors, and deletion of P2Y12Rs disturbs proliferation of neuronal precursors and leads to aberrant cortical cytoarchitecture during development and in adulthood. We propose that early developmental formation of somatic purinergic junctions represents an important interface for microglia to monitor the status of immature neurons and control neurodevelopment.
Collapse
Affiliation(s)
- Csaba Cserép
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary.
| | - Anett D Schwarcz
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Balázs Pósfai
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary; Szentágothai János Doctoral School of Neurosciences, Semmelweis University, 1083 Budapest, Hungary
| | - Zsófia I László
- "Momentum" Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, 1083 Budapest, Hungary; University of Dundee, School of Medicine, Dundee DD1 9SY, UK
| | - Anna Kellermayer
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Zsuzsanna Környei
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Máté Kisfali
- "Momentum" Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Miklós Nyerges
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Zsolt Lele
- "Momentum" Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - István Katona
- "Momentum" Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, 1083 Budapest, Hungary; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Ádám Dénes
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, 1083 Budapest, Hungary.
| |
Collapse
|
13
|
Méndez-Salcido FA, Torres-Flores MI, Ordaz B, Peña-Ortega F. Abnormal innate and learned behavior induced by neuron-microglia miscommunication is related to CA3 reconfiguration. Glia 2022; 70:1630-1651. [PMID: 35535571 DOI: 10.1002/glia.24185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 12/15/2022]
Abstract
Neuron-microglia communication through the Cx3cr1-Cx3cl1 axis is essential for the development and refinement of neural circuits, which determine their function into adulthood. In the present work we set out to extend the behavioral characterization of Cx3cr1-/- mice evaluating innate behaviors and spatial navigation, both dependent on hippocampal function. Our results show that Cx3cr1-deficient mice, which show some changes in microglial and synaptic terminals morphology and density, exhibit alterations in activities of daily living and in the rapid encoding of novel spatial information that, nonetheless, improves with training. A neural substrate for these cognitive deficiencies was found in the form of synaptic dysfunction in the CA3 region of the hippocampus, with a marked impact on the mossy fiber (MF) pathway. A network analysis of the CA3 microcircuit reveals the effect of these synaptic alterations on the functional connectivity among CA3 neurons with diminished strength and topological reorganization in Cx3cr1-deficient mice. Neonatal population activity of the CA3 region in Cx3cr1-deficient mice shows a marked reorganization around the giant depolarizing potentials, the first form of network-driven activity of the hippocampus, suggesting that alterations found in adult subjects arise early on in postnatal development, a critical period of microglia-dependent neural circuit refinement. Our results show that interruption of the Cx3cr1-Cx3cl1/neuron-microglia axis leads to changes in CA3 configuration that affect innate and learned behaviors.
Collapse
Affiliation(s)
- Felipe Antonio Méndez-Salcido
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, México
| | - Mayra Itzel Torres-Flores
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, México
| | - Benito Ordaz
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, México
| |
Collapse
|
14
|
Jiang M, Xie H, Zhang C, Wang T, Tian H, Lu L, Xu JY, Xu GT, Liu L, Zhang J. Enhancing fractalkine/CX3CR1 signalling pathway can reduce neuroinflammation by attenuating microglia activation in experimental diabetic retinopathy. J Cell Mol Med 2022; 26:1229-1244. [PMID: 35023309 PMCID: PMC8831940 DOI: 10.1111/jcmm.17179] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/12/2021] [Accepted: 12/19/2021] [Indexed: 12/19/2022] Open
Abstract
The concept of diabetic retinopathy (DR) has been extended from microvascular disease to neurovascular disease in which microglia activation plays a remarkable role. Fractalkine (FKN)/CX3CR1 is reported to regulate microglia activation in central nervous system diseases. To characterize the effect of FKN on microglia activation in DR, we employed streptozotocin‐induced diabetic rats, glyoxal‐treated R28 cells and hypoxia‐treated BV2 cells to mimic diabetic conditions and explored retinal neuronal apoptosis, reactive oxygen species (ROS), as well as the expressions of FKN, Iba‐1, TSPO, NF‐κB, Nrf2 and inflammation‐related cytokines. The results showed that FKN expression declined with diabetes progression and in glyoxal‐treated R28 cells. Compared with normal control, retinal microglia activation and inflammatory factors surged in both diabetic rat retinas and hypoxia‐treated microglia, which was largely dampened by FKN. The NF‐κB and Nrf2 expressions and intracellular ROS were up‐regulated in hypoxia‐treated microglia compared with that in normoxia control, and FKN significantly inhibited NF‐κB activation, activated Nrf2 pathway and decreased intracellular ROS. In conclusion, the results demonstrated that FKN deactivated microglia via inhibiting NF‐κB pathway and activating Nrf2 pathway, thus to reduce the production of inflammation‐related cytokines and ROS, and protect the retina from diabetes insult.
Collapse
Affiliation(s)
- Mengmeng Jiang
- Department of Ophthalmology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hai Xie
- Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Chaoyang Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Tianqin Wang
- Department of Ophthalmology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haibin Tian
- Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Lixia Lu
- Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Jing-Ying Xu
- Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Guo-Tong Xu
- Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Lin Liu
- Department of Ophthalmology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| |
Collapse
|
15
|
Abstract
In the twentieth century, neuropsychiatric disorders have been perceived solely from a neurone-centric point of view, which considers neurones as the key cellular elements of pathological processes. This dogma has been challenged thanks to the better comprehension of the brain functioning, which, even if far from being complete, has revealed the complexity of interactions that exist between neurones and neuroglia. Glial cells represent a highly heterogeneous population of cells of neural (astroglia and oligodendroglia) and non-neural (microglia) origin populating the central nervous system. The variety of glia reflects the innumerable functions that glial cells perform to support functions of the nervous system. Aberrant execution of glial functions contributes to the development of neuropsychiatric pathologies. Arguably, all types of glial cells are implicated in the neuropathology; however, astrocytes have received particular attention in recent years because of their pleiotropic functions that make them decisive in maintaining cerebral homeostasis. This chapter describes the multiple roles of astrocytes in the healthy central nervous system and discusses the diversity of astroglial responses in neuropsychiatric disorders suggesting that targeting astrocytes may represent an effective therapeutic strategy.
Collapse
|
16
|
Liu W, Danckwardt-Lillieström N, Schrott-Fischer A, Glueckert R, Rask-Andersen H. Distribution of Immune Cells Including Macrophages in the Human Cochlea. Front Neurol 2021; 12:781702. [PMID: 34880828 PMCID: PMC8645652 DOI: 10.3389/fneur.2021.781702] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/21/2021] [Indexed: 12/20/2022] Open
Abstract
Background: The human cochlea was earlier believed to lack capacity to mount specific immune responses. Recent studies established that the human cochlea holds macrophages. The cells appear to surveil, dispose of, and restore wasted cells to maintain tissue integrity. Macrophage activities are believed to be the central elements in immune responses and could swiftly defuse invading microbes that enter via adjacent infection-prone areas. This review updates recent human studies in light of the current literature and adds information about chemokine gene expression. Materials and Methods: We analyzed surgically obtained human tissue using immunohistochemistry, confocal microscopy, and multichannel super-resolution structured illumination microscopy. The samples were considered representative of steady-state conditions. Antibodies against the ionized calcium-binding adaptor molecule 1 were used to identify the macrophages. CD68 and CD11b, and the major histocompatibility complex type II (MHCII) and CD4 and CD8 were analyzed. The RNAscope technique was used for fractalkine gene localization. Results: Many macrophages were found around blood vessels in the stria vascularis but not CD4 and CD8 lymphocytes. Amoeboid macrophages were identified in the spiral ganglion with surveilling "antennae" projecting against targeted cells. Synapse-like contacts were seen on spiral ganglion cell bodies richly expressing single CXC3CL gene transcripts. Branching neurite-like processes extended along central and peripheral axons. Active macrophages were occasionally found near degenerating hair cells. Some macrophage-interacting T lymphocytes were observed between the scala tympani wall and Rosenthal's canal. CD4 and CD8 cells were not found in the organ of Corti. Conclusions: The results indicate that the human cochlea is equipped with macrophages and potentially lymphocytes, suggesting both an innate and adaptive immune capacity. A rich expression of fractalkine gene transcripts in spiral ganglion neurons suggest an essential role for auditory nerve protection, as has been demonstrated experimentally. The findings provide further information on the important role of the immune machinery present in the human inner ear and its potential to carry adverse immune reactions, including cytotoxic and foreign body responses. The results can be used to form a rationale for therapies aiming to modulate these immune activities.
Collapse
Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Niklas Danckwardt-Lillieström
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Anneliese Schrott-Fischer
- Inner Ear Laboratory, Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Inner Ear Laboratory, Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| |
Collapse
|
17
|
Wang XL, Li L. Microglia Regulate Neuronal Circuits in Homeostatic and High-Fat Diet-Induced Inflammatory Conditions. Front Cell Neurosci 2021; 15:722028. [PMID: 34720877 PMCID: PMC8549960 DOI: 10.3389/fncel.2021.722028] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/27/2021] [Indexed: 12/12/2022] Open
Abstract
Microglia are brain resident macrophages, which actively survey the surrounding microenvironment and promote tissue homeostasis under physiological conditions. During this process, microglia participate in synaptic remodeling, neurogenesis, elimination of unwanted neurons and cellular debris. The complex interplay between microglia and neurons drives the formation of functional neuronal connections and maintains an optimal neural network. However, activation of microglia induced by chronic inflammation increases synaptic phagocytosis and leads to neuronal impairment or death. Microglial dysfunction is implicated in almost all brain diseases and leads to long-lasting functional deficiency, such as hippocampus-related cognitive decline and hypothalamus-associated energy imbalance (i.e., obesity). High-fat diet (HFD) consumption triggers mediobasal hypothalamic microglial activation and inflammation. Moreover, HFD-induced inflammation results in cognitive deficits by triggering hippocampal microglial activation. Here, we have summarized the current knowledge of microglial characteristics and biological functions and also reviewed the molecular mechanism of microglia in shaping neural circuitries mainly related to cognition and energy balance in homeostatic and diet-induced inflammatory conditions.
Collapse
Affiliation(s)
- Xiao-Lan Wang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lianjian Li
- Department of Surgery, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, China.,Hubei Province Academy of Traditional Chinese Medicine, Wuhan, China
| |
Collapse
|
18
|
He GL, Wang ZZ, Yu XT, Shen TT, Luo Z, Li P, Luo X, Tan YL, Gao P, Yang XS. The involvement of microglial CX3CR1 in heat acclimation-induced amelioration of adult hippocampal neurogenesis impairment in EMF-exposed mice. Brain Res Bull 2021; 177:181-193. [PMID: 34555433 DOI: 10.1016/j.brainresbull.2021.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/17/2021] [Indexed: 12/12/2022]
Abstract
Microglial CX3C chemokine receptor 1 (CX3CR1) has been implicated in numerous cellular mechanisms, including signalling pathways that regulate brain homoeostasis and adult hippocampal neurogenesis. Specific environmental conditions can impair hippocampal neurogenesis-related cognition, learning and memory. However, the role of CX3CR1 in the neurogenic alterations resulting from the cross-tolerance protection conferred by heat acclimation (HA) against the effects of electromagnetic field (EMF) exposure is less well understood. Here, we investigated the role of microglial CX3CR1 signalling in adult hippocampal neurogenesis induced by HA in EMF-exposed mice. We found that EMF exposure significantly decreased the number of proliferating and differentiating cells in the dentate gyrus (DG) of the hippocampus, resulting in a reduced neurogenesis rate. Moreover, alterations in the phenotypes of activated microglia and decreased expression levels of CX3CR1, but not sirtuin 1 (SIRT1), were observed in the brains of EMF-exposed mice. Remarkably, HA treatment improved microglial phenotypes, restored the expression of CX3CR1, and ameliorated the decrease in the adult hippocampal neurogenesis rate following EMF exposure. Moreover, pharmacological inhibition of CX3CR1 and SIRT1 failed to restore CX3CR1 expression and ameliorate hippocampal neurogenesis impairment following HA plus EMF stimulation. These results indicate that microglial CX3CR1 is involved in the cross-tolerance protective effect of HA on adult hippocampal neurogenesis upon EMF exposure.
Collapse
Affiliation(s)
- Gen-Lin He
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Ze-Ze Wang
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Xue-Ting Yu
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Ting-Ting Shen
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Zhen Luo
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Ping Li
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Xue Luo
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Yu-Long Tan
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Peng Gao
- Key Laboratory of Medical Protection for Electromagnetic Radiation Ministry of Education, Army Medical University, Chongqing, China
| | - Xue-Sen Yang
- Department of Tropical Medicine, Army Medical University, Chongqing, China; Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China.
| |
Collapse
|
19
|
Advances in microglia cellular models: focus on extracellular vesicle production. Biochem Soc Trans 2021; 49:1791-1802. [PMID: 34415299 DOI: 10.1042/bst20210203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/05/2021] [Accepted: 07/15/2021] [Indexed: 12/19/2022]
Abstract
Microglia are the major component of the innate immune system in the central nervous system. They promote the maintenance of brain homeostasis as well as support inflammatory processes that are often related to pathological conditions such as neurodegenerative diseases. Depending on the stimulus received, microglia cells dynamically change their phenotype releasing specific soluble factors and largely modify the cargo of their secreted extracellular vesicles (EVs). Despite the mechanisms at the basis of microglia actions have not been completely clarified, the recognized functions exerted by their EVs in patho-physiological conditions represent the proof of the crucial role of these organelles in tuning cell-to-cell communication, promoting either protective or harmful effects. Consistently, in vitro cell models to better elucidate microglia EV production and mechanisms of their release have been increased in the last years. In this review, the main microglial cellular models that have been developed and validated will be described and discussed, with particular focus on those used to produce and derive EVs. The advantages and disadvantages of their use will be evidenced too. Finally, given the wide interest in applying EVs in diagnosis and therapy too, the heterogeneity of available models for producing microglia EVs is here underlined, to prompt a cross-check or comparison among them.
Collapse
|
20
|
Turkin A, Tuchina O, Klempin F. Microglia Function on Precursor Cells in the Adult Hippocampus and Their Responsiveness to Serotonin Signaling. Front Cell Dev Biol 2021; 9:665739. [PMID: 34109176 PMCID: PMC8182052 DOI: 10.3389/fcell.2021.665739] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/12/2021] [Indexed: 12/18/2022] Open
Abstract
Microglia are the resident immune cells of the adult brain that become activated in response to pathogen- or damage-associated stimuli. The acute inflammatory response to injury, stress, or infection comprises the release of cytokines and phagocytosis of damaged cells. Accumulating evidence indicates chronic microglia-mediated inflammation in diseases of the central nervous system, most notably neurodegenerative disorders, that is associated with disease progression. To understand microglia function in pathology, knowledge of microglia communication with their surroundings during normal state and the release of neurotrophins and growth factors in order to maintain homeostasis of neural circuits is of importance. Recent evidence shows that microglia interact with serotonin, the neurotransmitter crucially involved in adult neurogenesis, and known for its role in antidepressant action. In this chapter, we illustrate how microglia contribute to neuroplasticity of the hippocampus and interact with local factors, e.g., BDNF, and external stimuli that promote neurogenesis. We summarize the recent findings on the role of various receptors in microglia-mediated neurotransmission and particularly focus on microglia’s response to serotonin signaling. We review microglia function in neuroinflammation and neurodegeneration and discuss their novel role in antidepressant mechanisms. This synopsis sheds light on microglia in healthy brain and pathology that involves serotonin and may be a potential therapeutic model by which microglia play a crucial role in the maintenance of mood.
Collapse
Affiliation(s)
- Andrei Turkin
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Oksana Tuchina
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Friederike Klempin
- Department of Psychiatry and Psychotherapy, Charité University Medicine Berlin, Berlin, Germany
| |
Collapse
|
21
|
Eshraghi M, Adlimoghaddam A, Mahmoodzadeh A, Sharifzad F, Yasavoli-Sharahi H, Lorzadeh S, Albensi BC, Ghavami S. Alzheimer's Disease Pathogenesis: Role of Autophagy and Mitophagy Focusing in Microglia. Int J Mol Sci 2021; 22:3330. [PMID: 33805142 PMCID: PMC8036323 DOI: 10.3390/ijms22073330] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/14/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is a debilitating neurological disorder, and currently, there is no cure for it. Several pathologic alterations have been described in the brain of AD patients, but the ultimate causative mechanisms of AD are still elusive. The classic hallmarks of AD, including amyloid plaques (Aβ) and tau tangles (tau), are the most studied features of AD. Unfortunately, all the efforts targeting these pathologies have failed to show the desired efficacy in AD patients so far. Neuroinflammation and impaired autophagy are two other main known pathologies in AD. It has been reported that these pathologies exist in AD brain long before the emergence of any clinical manifestation of AD. Microglia are the main inflammatory cells in the brain and are considered by many researchers as the next hope for finding a viable therapeutic target in AD. Interestingly, it appears that the autophagy and mitophagy are also changed in these cells in AD. Inside the cells, autophagy and inflammation interact in a bidirectional manner. In the current review, we briefly discussed an overview on autophagy and mitophagy in AD and then provided a comprehensive discussion on the role of these pathways in microglia and their involvement in AD pathogenesis.
Collapse
Affiliation(s)
- Mehdi Eshraghi
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA;
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Aida Adlimoghaddam
- St. Boniface Hospital Albrechtsen Research Centre, Division of Neurodegenerative Disorders, Winnipeg, MB R2H2A6, Canada; (A.A.); (B.C.A.)
| | - Amir Mahmoodzadeh
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran;
| | - Farzaneh Sharifzad
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; (F.S.); (H.Y.-S.)
| | - Hamed Yasavoli-Sharahi
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; (F.S.); (H.Y.-S.)
| | - Shahrokh Lorzadeh
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
| | - Benedict C. Albensi
- St. Boniface Hospital Albrechtsen Research Centre, Division of Neurodegenerative Disorders, Winnipeg, MB R2H2A6, Canada; (A.A.); (B.C.A.)
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Research Institute of Oncology and Hematology, Cancer Care Manitoba-University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Biology of Breathing Theme, Children Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Faculty of Medicine, Katowice School of Technology, 40-555 Katowice, Poland
| |
Collapse
|
22
|
Promotion of Momordica Charantia polysaccharides on neural stem cell proliferation by increasing SIRT1 activity after cerebral ischemia/reperfusion in rats. Brain Res Bull 2021; 170:254-263. [PMID: 33647420 DOI: 10.1016/j.brainresbull.2021.02.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/22/2021] [Accepted: 02/16/2021] [Indexed: 11/24/2022]
Abstract
The deacetylase SIRT1 has been reported to play a critical role in regulating neurogenesis, which may be an adaptive processes contributing to recovery after stroke. Our previous work showed that the antioxidant capacity of Momordica charantia polysaccharides (MCPs) could protect against cerebral ischemia/reperfusion (I/R) after stroke. However, whether the protective effect of MCPs on I/R injury is related to neural stem cell (NSC) proliferation remains unclear. In the present study, we designed invivo and invitro experiments to elucidate the underlying mechanisms by which MCPs promote endogenous NSC proliferation during cerebral I/R. Invivo results showed that MCPs rescued the memory and learning abilities of rats after I/R damage and enhanced NSC proliferation in the rat subventricular zone (SVZ) and subgrannular zone (SGZ) during I/R. Invitro experiments demonstrated that MCPs could stimulate the proliferation of C17.2 cells under oxygen-glucose deprivation (OGD) conditions. Further studies revealed that the proliferation-promoting mechanism of MCPs relied on increasing the activity of SIRT1, decreasing the level of acetylation of β-catenin in the cytoplasm, and then triggering the translocation of β-catenin into the nucleus. These data provide experimental evidence that the up-regulation of SIRT1 activity by MCPs led to an increased cytoplasmic deacetylation of β-catenin, which promoted translocation of β-catenin to the nucleus to participate in the signaling pathway involved in NSC proliferation. The present study reveals that MCPs function as a therapeutic drug to promote stroke recovery by increasing the activity of SIRT1, decreasing the level of acetylated β-catenin, promoting the nuclear translocation of β-catenin and thereby increasing endogenous NSC proliferation.
Collapse
|
23
|
Hemonnot-Girard AL, Valverde AJ, Hua J, Delaygue C, Linck N, Maurice T, Rassendren F, Hirbec H. Analysis of CX3CR1 haplodeficiency in male and female APP swe/PSEN1 dE9 mice along Alzheimer disease progression. Brain Behav Immun 2021; 91:404-417. [PMID: 33190798 DOI: 10.1016/j.bbi.2020.10.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/02/2020] [Accepted: 10/21/2020] [Indexed: 01/22/2023] Open
Abstract
Microglia, the resident immune cells of the brain, have recently emerged as key players in Alzheimer Disease (AD) pathogenesis, but their roles in AD remain largely elusive and require further investigation. Microglia functions are readily altered when isolated from their brain environment, and microglia reporter mice thus represent valuable tools to study the contribution of these cells to neurodegenerative diseases such as AD. The CX3CR1+/eGFP mice is one of the most popular microglia reporter mice, and has been used in numerous studies to investigate in vivo microglial functions, including in the context of AD research. However, until now, the impact of CX3CR1 haplodeficiency on the typical features of Alzheimer Disease has not been studied in depth. To fill this gap, we generated APPswe/PSEN1dE9:CX3CR1+/eGFP mice and analyzed these mice for Alzheimer's like pathology and neuroinflammation hallmarks. More specifically, using robust multifactorial statistical and multivariate analyses, we investigated the impact of CX3CR1 deficiency in both males and females, at three typical stages of the pathology progression: at early stage when Amyloid-β (Aβ) deposition just starts, at intermediate stage during Aβ accumulation phase and at more advanced stages when Aβ plaque number stabilizes. We found that CX3CR1 haplodeficiency had little impact on the progression of the pathology in the APPswe/PSEN1dE9 model and demonstrated that the APPswe/PSEN1dE9:CX3CR1+/eGFP line is a relevant and useful model to study the role of microglia in Alzheimer Disease. In addition, although Aβ plaques density is higher in females compared to age-matched males, we show that their glial reaction, inflammation status and memory deficits are not different.
Collapse
Affiliation(s)
- Anne-Laure Hemonnot-Girard
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Audrey J Valverde
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Jennifer Hua
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Charlene Delaygue
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Nathalie Linck
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Tangui Maurice
- MNDN, University of Montpellier, EPHE, INSERM, Montpellier, France
| | - François Rassendren
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France
| | - Helene Hirbec
- IGF, Institut de Génomique Fonctionnelle, University of Montpellier, CNRS, INSERM, Montpellier, France; Labex ICST, Montpellier, France.
| |
Collapse
|
24
|
Dos Santos IRC, Dias MNC, Gomes-Leal W. Microglial activation and adult neurogenesis after brain stroke. Neural Regen Res 2021; 16:456-459. [PMID: 32985465 PMCID: PMC7996005 DOI: 10.4103/1673-5374.291383] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery that new neurons are produced in some regions of the adult mammalian brain is a paradigm-shift in neuroscience research. These new-born cells are produced from neuroprogenitors mainly in the subventricular zone at the margin of the lateral ventricle, subgranular zone in the hippocampal dentate gyrus and in the striatum, a component of the basal ganglia, even in humans. In the human hippocampus, neuroblasts are produced even in elderlies. The regulation of adult neurogenesis is a complex phenomenon involving a multitude of molecules, neurotransmitters and soluble factors released by different sources including glial cells. Microglia, the resident macrophages of the central nervous system, are considered to play an important role on the regulation of adult neurogenesis both in physiological and pathological conditions. Following stroke and other acute neural disorders, there is an increase in the numbers of neuroblast production in the neurogenic niches. Microglial activation is believed to display both beneficial and detrimental role on adult neurogenesis after stroke, depending on the activation level and brain location. In this article, we review the scientific evidence addressing the role of microglial activation on adult neurogenesis after ischemia. A comprehensive understanding of the microglial role after stroke and other neural disorders it is an important step for development of future therapies based on manipulation of adult neurogenesis.
Collapse
Affiliation(s)
- Ijair R C Dos Santos
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará-Brazil, Belém-Pará, Brazil
| | - Michelle Nerissa C Dias
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará-Brazil, Belém-Pará, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará-Brazil, Belém-Pará, Brazil
| |
Collapse
|
25
|
Cserép C, Pósfai B, Dénes Á. Shaping Neuronal Fate: Functional Heterogeneity of Direct Microglia-Neuron Interactions. Neuron 2020; 109:222-240. [PMID: 33271068 DOI: 10.1016/j.neuron.2020.11.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/13/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
The functional contribution of microglia to normal brain development, healthy brain function, and neurological disorders is increasingly recognized. However, until recently, the nature of intercellular interactions mediating these effects remained largely unclear. Recent findings show microglia establishing direct contact with different compartments of neurons. Although communication between microglia and neurons involves intermediate cells and soluble factors, direct membrane contacts enable a more precisely regulated, dynamic, and highly effective form of interaction for fine-tuning neuronal responses and fate. Here, we summarize the known ultrastructural, molecular, and functional features of direct microglia-neuron interactions and their roles in brain disease.
Collapse
Affiliation(s)
- Csaba Cserép
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary
| | - Balázs Pósfai
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary; Szentágothai János Doctoral School of Neurosciences, Semmelweis University, Üllői út 26, 1085 Budapest, Hungary
| | - Ádám Dénes
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Szigony u. 43, 1083 Budapest, Hungary.
| |
Collapse
|
26
|
Qu C, Qu C, Xu L, Shen J, Lv D, Li Y, Song H, Li T, Zheng J, Zhang J. Nuclear receptor TLX may be through regulating the SIRT1/NF-κB pathway to ameliorate cognitive impairment in chronic cerebral hypoperfusion. Brain Res Bull 2020; 166:142-149. [PMID: 33197535 DOI: 10.1016/j.brainresbull.2020.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 11/05/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Chronic cerebral hypoperfusion (CCH) is a common pathophysiological mechanism in neurodegenerative diseases, such as Alzheimer's disease and vascular dementia. The orphan nuclear receptor TLX plays an important role in neural development, adult neurogenesis and cognition. The aim of this study was to investigate the neuroprotective effects of TLX on cognitive dysfunction, hippocampal neurogenesis and neuroinflammation in a rat model of CCH and to assess the possible mechanisms. METHODS Permanent bilateral common carotid artery occlusion (2-VO) was used to establish a model of CCH. Stereotaxic injection of an adeno-associated virus vector expressing TLX was used to overexpress TLX in the hippocampus. Cognitive function was evaluated by the Morris Water Maze test. Immunofluorescent staining was used to assess hippocampal neurogenesis. The effects of overexpression of TLX on SIRT1 and inflammatory cytokines were analyzed with qRT-PCR and western blot. RESULT After 2-VO, CCH rats exhibited cognitive impairment and reduction of hippocampal TLX levels. Overexpression of TLX ameliorated cognitive impairments with increasing number of BrdU + cells and BrdU + NeuN + cells in DG. Furthermore, TLX rescued the reduced SIRT1 usually induced by CCH. Additionally, TLX also inhibited the expression of inflammatory cytokines such as NF-κB and IL-1β. CONCLUSIONS The present findings suggested that TLX exerted protective effects against cognitive deficits induced by CCH. The possible mechanisms of TLX may be through regulating the SIRT1/NF-κB pathway, promoting hippocampal neurogenesis and inhibiting the neuroinflammatory response.
Collapse
Affiliation(s)
- Chujie Qu
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Changhua Qu
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Linling Xu
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Jun Shen
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Dongwei Lv
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Yaqing Li
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Hao Song
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Tian Li
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Jiaxin Zheng
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China
| | - Junjian Zhang
- Department of Neurology, Zhongnan Hospital, Wuhan University, No.169, Donghu Road, Wuhan, 430071, Hubei, China.
| |
Collapse
|
27
|
Araki T, Ikegaya Y, Koyama R. The effects of microglia‐ and astrocyte‐derived factors on neurogenesis in health and disease. Eur J Neurosci 2020; 54:5880-5901. [PMID: 32920880 PMCID: PMC8451940 DOI: 10.1111/ejn.14969] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022]
Abstract
Hippocampal neurogenesis continues throughout life and has been suggested to play an essential role in maintaining spatial cognitive function under physiological conditions. An increasing amount of evidence has indicated that adult neurogenesis is tightly controlled by environmental conditions in the neurogenic niche, which consists of multiple types of cells including microglia and astrocytes. Microglia maintain the environment of neurogenic niche through their phagocytic capacity and interaction with neurons via fractalkine‐CX3CR1 signaling. In addition, microglia release growth factors such as brain‐derived neurotrophic factor (BDNF) and cytokines such as tumor necrosis factor (TNF)‐α to support the development of adult born neurons. Astrocytes also manipulate neurogenesis by releasing various soluble factors including adenosine triphosphate and lactate. Whereas, under pathological conditions such as Alzheimer's disease, depression, and epilepsy, microglia and astrocytes play a leading role in inflammation and are involved in attenuating the normal process of neurogenesis. The modulation of glial functions on neurogenesis in these brain diseases are attracting attention as a new therapeutic target. This review describes how these glial cells play a role in adult hippocampal neurogenesis in both health and disease, especially focusing glia‐derived factors.
Collapse
Affiliation(s)
- Tasuku Araki
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
- Center for Information and Neural Networks Suita City Osaka Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
| |
Collapse
|
28
|
Morris G, Puri BK, Maes M, Olive L, Berk M, Carvalho AF. The role of microglia in neuroprogressive disorders: mechanisms and possible neurotherapeutic effects of induced ketosis. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109858. [PMID: 31923453 DOI: 10.1016/j.pnpbp.2020.109858] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 12/23/2022]
Abstract
A comprehensive review of molecular mechanisms involved in the promotion and maintenance of distinct microglia phenotypes is provided. The acquisition and perpetuation of predominantly pro-inflammatory microglial phenotypes have been implicated in the pathophysiology of several neuroprogressive diseases and is associated with reduced ATP production via oxidative phosphorylation, increased ATP generation by glycolysis, elevated oxidative and nitrosative stress and other metabolic, inflammatory and hormonal insults. Microglia can also adopt a predominantly anti-inflammatory phenotypes with neuroprotective properties. Strategies that promote and maintain a predominantly anti-inflammatory phenotype may hold promise as novel therapeutic opportunities for neuroprogressive illness. Induced ketosis may promote a transition towards predominantly anti-inflammatory microglial states/phenotypes by several mechanisms, including inhibition of glycolysis and increased NAD+ production; engagement of microglial GPR109A receptors; histone deacetylase inhibition; and elevated n-3 polyunsaturated fatty acids levels. Since microglia activation can now be assessed in vivo, these data provide a clear rationale for the design of transdiagnostic randomized controlled trials of the ketogenic diet and other ketosis-inducing strategies for neuroprogressive diseases, which may also provide mechanistic insights through the assessment of "target engagement".
Collapse
Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | | | - Michael Maes
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Lisa Olive
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andre F Carvalho
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
| |
Collapse
|
29
|
A role for the orphan nuclear receptor TLX in the interaction between neural precursor cells and microglia. Neuronal Signal 2020; 3:NS20180177. [PMID: 32269832 PMCID: PMC7104222 DOI: 10.1042/ns20180177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 12/11/2018] [Accepted: 12/17/2018] [Indexed: 02/06/2023] Open
Abstract
Microglia are an essential component of the neurogenic niche in the adult hippocampus and are involved in the control of neural precursor cell (NPC) proliferation, differentiation and the survival and integration of newborn neurons in hippocampal circuitry. Microglial and neuronal cross-talk is mediated in part by the chemokine fractalkine/chemokine (C-X3-C motif) ligand 1 (CX3CL1) released from neurons, and its receptor CX3C chemokine receptor 1 (CX3CR1) which is expressed on microglia. A disruption in this pathway has been associated with impaired neurogenesis yet the specific molecular mechanisms by which this interaction occurs remain unclear. The orphan nuclear receptor TLX (Nr2e1; homologue of the Drosophila tailless gene) is a key regulator of hippocampal neurogenesis, and we have shown that in its absence microglia exhibit a pro-inflammatory activation phenotype. However, it is unclear whether a disturbance in CX3CL1/CX3CR1 communication mediates an impairment in TLX-related pathways which may have subsequent effects on neurogenesis. To this end, we assessed miRNA expression of up- and down-stream signalling molecules of TLX in the hippocampus of mice lacking CX3CR1. Our results demonstrate that a lack of CX3CR1 is associated with altered expression of TLX and its downstream targets in the hippocampus without significantly affecting upstream regulators of TLX. Thus, TLX may be a potential participant in neural stem cell (NSC)-microglial cross-talk and may be an important target in understanding inflammatory-associated impairments in neurogenesis.
Collapse
|
30
|
Vidal PM, Pacheco R. The Cross-Talk Between the Dopaminergic and the Immune System Involved in Schizophrenia. Front Pharmacol 2020; 11:394. [PMID: 32296337 PMCID: PMC7137825 DOI: 10.3389/fphar.2020.00394] [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: 10/29/2019] [Accepted: 03/16/2020] [Indexed: 12/14/2022] Open
Abstract
Dopamine is one of the neurotransmitters whose transmission is altered in a number of neural pathways in the brain of schizophrenic patients. Current evidence indicates that these alterations involve hyperactive dopaminergic transmission in mesolimbic areas, striatum, and hippocampus, whereas hypoactive dopaminergic transmission has been reported in the prefrontal cortex of schizophrenic patients. Consequently, schizophrenia is associated with several cognitive and behavioral alterations. Of note, the immune system has been found to collaborate with the central nervous system in a number of cognitive and behavioral functions, which are dysregulated in schizophrenia. Moreover, emerging evidence has associated schizophrenia and inflammation. Importantly, different lines of evidence have shown dopamine as a major regulator of inflammation. In this regard, dopamine might exert strong regulation in the activity, migration, differentiation, and proliferation of immune cells that have been shown to contribute to cognitive functions, including T-cells, microglial cells, and peripheral monocytes. Thereby, alterations in dopamine levels associated to schizophrenia might affect inflammatory response of immune cells and consequently some behavioral functions, including reference memory, learning, social behavior, and stress resilience. Altogether these findings support the involvement of an active cross-talk between the dopaminergic and immune systems in the physiopathology of schizophrenia. In this review we summarize, integrate, and discuss the current evidence indicating the involvement of an altered dopaminergic regulation of immunity in schizophrenia.
Collapse
Affiliation(s)
- Pia M Vidal
- Department of Basic Science, Biomedical Science Research Lab, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile.,Laboratorio de Neuroinmunología, Fundación Ciencia & Vida, Santiago, Chile
| | - Rodrigo Pacheco
- Laboratorio de Neuroinmunología, Fundación Ciencia & Vida, Santiago, Chile.,Universidad San Sebastián, Santiago, Chile
| |
Collapse
|
31
|
Montagud-Romero S, Montesinos J, Pavón FJ, Blanco-Gandia MC, Ballestín R, Rodríguez de Fonseca F, Miñarro J, Guerri C, Rodríguez-Arias M. Social defeat-induced increase in the conditioned rewarding effects of cocaine: Role of CX3CL1. Prog Neuropsychopharmacol Biol Psychiatry 2020; 96:109753. [PMID: 31446159 DOI: 10.1016/j.pnpbp.2019.109753] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/27/2019] [Accepted: 08/21/2019] [Indexed: 12/17/2022]
Abstract
Social stress is associated with higher vulnerability to drug use, as it enhances the reinforcing effects of psychostimulants in rodents. Furthermore, continued or severe stress induces a proinflammatory state of microglial activation and augmented cytokine production. The aim of the present work was to evaluate the role of fractalkine [C-X3-C motif ligand 1 (CX3CL1)], an inflammatory chemokine, in the increased conditioned rewarding effects of cocaine in animals exposed to social defeat stress. In addition, we measured the signaling cascade pathway of CX3CL1 in the hippocampus (HPC) (including p-ERK/ERK, p-p38/p38 MAPK, p-p65/p65 NFκB and p-CREB/CREB ratios). The glutamate receptor subunits NR1, NR2B and GluA1 were also assessed. A total of 102 adult male C57BL/6 J wild-type (WT) and Cx3cr1 knockout (KO) mice were divided into different experimental groups according to stress condition (exploration or social defeat). Three weeks after the last social defeat, conditioned place preference (CPP) was induced by a subthreshold dose of cocaine (1 mg/kg). Brain tissue samples were taken 24 h after the CPP procedure to determine the levels of the proteins and transcription factors. Our results showed that, in WT animals, repeated social defeat (RSD) decreased CX3CL1 striatal levels without producing changes in the HPC. In addition, RSD induced an increase in the conditioned rewarding effects of cocaine, regardless of the genotype. After CPP induced by cocaine, defeated Cx3cr1-deficient mice showed a decrease in the p-p65/p65 NFκB and pCREB/CREB ratio in the HPC, and an increase in the hippocampal levels of CX3CL1 and p-p38/p38 MAPK relation. In all defeated mice, there was a decrease in the ionotropic glutamate receptor subunit NR1. In conclusion, these results suggest that the lack of CX3CL1/Cx3cr1 signaling under stress conditions induces changes in protein and transcription factors, indicating that CX3CL1 is needed to shield the response to social defeat.
Collapse
Affiliation(s)
- Sandra Montagud-Romero
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain
| | - Jorge Montesinos
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia 46012, Spain; Department of Neurology, Columbia University Medical Center, New York, USA
| | - Francisco Javier Pavón
- Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain; Unidad de Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga/Universidad de Málaga, Málaga 29010, Spain
| | - M Carmen Blanco-Gandia
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain
| | - Raúl Ballestín
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain; Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain
| | - Fernando Rodríguez de Fonseca
- Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain; Unidad de Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga/Universidad de Málaga, Málaga 29010, Spain
| | - José Miñarro
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain; Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain
| | - Consuelo Guerri
- Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain; Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia 46012, Spain
| | - Marta Rodríguez-Arias
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain; Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain.
| |
Collapse
|
32
|
Chamera K, Trojan E, Szuster-Głuszczak M, Basta-Kaim A. The Potential Role of Dysfunctions in Neuron-Microglia Communication in the Pathogenesis of Brain Disorders. Curr Neuropharmacol 2020; 18:408-430. [PMID: 31729301 PMCID: PMC7457436 DOI: 10.2174/1570159x17666191113101629] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/15/2019] [Accepted: 11/10/2019] [Indexed: 12/18/2022] Open
Abstract
The bidirectional communication between neurons and microglia is fundamental for the proper functioning of the central nervous system (CNS). Chemokines and clusters of differentiation (CD) along with their receptors represent ligand-receptor signalling that is uniquely important for neuron - microglia communication. Among these molecules, CX3CL1 (fractalkine) and CD200 (OX-2 membrane glycoprotein) come to the fore because of their cell-type-specific localization. They are principally expressed by neurons when their receptors, CX3CR1 and CD200R, respectively, are predominantly present on the microglia, resulting in the specific axis which maintains the CNS homeostasis. Disruptions to this balance are suggested as contributors or even the basis for many neurological diseases. In this review, we discuss the roles of CX3CL1, CD200 and their receptors in both physiological and pathological processes within the CNS. We want to underline the critical involvement of these molecules in controlling neuron - microglia communication, noting that dysfunctions in their interactions constitute a key factor in severe neurological diseases, such as schizophrenia, depression and neurodegeneration-based conditions.
Collapse
Affiliation(s)
- Katarzyna Chamera
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Ewa Trojan
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Magdalena Szuster-Głuszczak
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Agnieszka Basta-Kaim
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| |
Collapse
|
33
|
Gyoneva S, Hosur R, Gosselin D, Zhang B, Ouyang Z, Cotleur AC, Peterson M, Allaire N, Challa R, Cullen P, Roberts C, Miao K, Reynolds TL, Glass CK, Burkly L, Ransohoff RM. Cx3cr1-deficient microglia exhibit a premature aging transcriptome. Life Sci Alliance 2019; 2:2/6/e201900453. [PMID: 31792059 PMCID: PMC6892408 DOI: 10.26508/lsa.201900453] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/14/2019] [Accepted: 11/17/2019] [Indexed: 12/13/2022] Open
Abstract
Gyoneva et al use RNA-seq to show that Cx3cr1-deficient microglia in young mice display a gene expression profile similar to microglia in aged mice, suggesting premature microglial aging. CX3CR1, one of the highest expressed genes in microglia in mice and humans, is implicated in numerous microglial functions. However, the molecular mechanisms underlying Cx3cr1 signaling are not well understood. Here, we analyzed transcriptomes of Cx3cr1-deficient microglia under varying conditions by RNA-sequencing (RNA-seq). In 2-mo-old mice, Cx3cr1 deletion resulted in the down-regulation of a subset of immune-related genes, without substantial epigenetic changes in markers of active chromatin. Surprisingly, Cx3cr1-deficient microglia from young mice exhibited a transcriptome consistent with that of aged Cx3cr1-sufficient animals, suggesting a premature aging transcriptomic signature. Immunohistochemical analysis of microglia in young and aged mice revealed that loss of Cx3cr1 modulates microglial morphology in a comparable fashion. Our results suggest that CX3CR1 may regulate microglial function in part by modulating the expression levels of a subset of inflammatory genes during chronological aging, making Cx3cr1-deficient mice useful for studying aged microglia.
Collapse
Affiliation(s)
| | | | - David Gosselin
- Cell and Molecular Medicine, University of California San Diego, San Diego, CA, USA
| | - Baohong Zhang
- Computational Biology and Genomics, Biogen, Cambridge, MA, USA
| | - Zhengyu Ouyang
- Cell and Molecular Medicine, University of California San Diego, San Diego, CA, USA
| | | | | | - Norm Allaire
- Computational Biology and Genomics, Biogen, Cambridge, MA, USA
| | - Ravi Challa
- Computational Biology and Genomics, Biogen, Cambridge, MA, USA
| | - Patrick Cullen
- Computational Biology and Genomics, Biogen, Cambridge, MA, USA
| | - Chris Roberts
- Computational Biology and Genomics, Biogen, Cambridge, MA, USA
| | - Kelly Miao
- Acute Neurology, Biogen, Cambridge, MA, USA
| | | | - Christopher K Glass
- Cell and Molecular Medicine, University of California San Diego, San Diego, CA, USA.,School of Medicine, University of California San Diego, San Diego, CA, USA
| | | | | |
Collapse
|
34
|
Valiati FE, Hizo GH, Pinto JV, Kauer-Sant`Anna M. The Possible Role of Telomere Length and Chemokines in the Aging Process: A Transdiagnostic Review in Psychiatry. CURRENT PSYCHIATRY RESEARCH AND REVIEWS 2019. [DOI: 10.2174/1573400515666190719155906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:Psychiatric disorders are common, reaching a worldwide prevalence of 29.2%. They are associated with a high risk of premature death and with accelerated aging in clinical, molecular and neuroimaging studies. Recently, there is strong evidence suggesting a possible role of telomere length and chemokines in aging processes in psychiatric disorders.Objective:We aimed to review the literature on telomere length and chemokines and its association with early aging in mental illnesses on a transdiagnostic approach.Results:The review highlights the association between psychiatric disorders and early aging. Several independent studies have reported shorter telomere length and dysregulations on levels of circulating chemokines in schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorders, suggesting a complex interaction between these markers in a transdiagnostic level. However, studies have investigated the inflammatory markers and telomere shortening separately and associated with a particular diagnosis, rather than as a transdiagnostic biological feature.Conclusion:There is consistent evidence supporting the relationship between accelerated aging, telomere length, and chemokines in mental disorders, but they have been studied individually. Thus, more research is needed to improve the knowledge of accelerated senescence and its biomarkers in psychiatry, not only individually in each diagnosis, but also based on a transdiagnostic perspective. Moreover, further research should try to elucidate how the intricate association between the chemokines and telomeres together may contribute to the aging process in psychiatric disorders.
Collapse
Affiliation(s)
- Fernanda Endler Valiati
- Laboratory of Molecular Psychiatry, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Gabriel Henrique Hizo
- Laboratory of Molecular Psychiatry, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Jairo Vinícius Pinto
- Laboratory of Molecular Psychiatry, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Márcia Kauer-Sant`Anna
- Laboratory of Molecular Psychiatry, Experimental Research Center, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| |
Collapse
|
35
|
Systematic Identification of Cell-Cell Communication Networks in the Developing Brain. iScience 2019; 21:273-287. [PMID: 31677479 PMCID: PMC6838536 DOI: 10.1016/j.isci.2019.10.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 09/24/2019] [Accepted: 10/13/2019] [Indexed: 01/07/2023] Open
Abstract
Since the generation of cell-type specific knockout models, the importance of inter-cellular communication between neural, vascular, and microglial cells during neural development has been increasingly appreciated. However, the extent of communication between these major cell populations remains to be systematically mapped. Here, we describe EMBRACE (embryonic brain cell extraction using FACS), a method to simultaneously isolate neural, mural, endothelial, and microglial cells to more than 94% purity in ∼4 h. Utilizing EMBRACE we isolate, transcriptionally analyze, and build a cell-cell communication map of the developing mouse brain. We identify 1,710 unique ligand-receptor interactions between neural, endothelial, mural, and microglial cells in silico and experimentally confirm the APOE-LDLR, APOE-LRP1, VTN-KDR, and LAMA4-ITGB1 interactions in the E14.5 brain. We provide our data via the searchable “Brain interactome explorer”, available at https://mpi-ie.shinyapps.io/braininteractomeexplorer/. Together, this study provides a comprehensive map that reveals the richness of communication within the developing brain. Isolation of embryonic neural, mural, endothelial, and microglial cells to >94% purity Transcriptome analyses of neural, vascular, and microglial cells from E14.5 brain Generation of inter-cellular communication network with 1,710 unique interactions Established “Brain interactome explorer,” a searchable cell communication database
Collapse
|
36
|
Stamatovic SM, Phillips CM, Martinez-Revollar G, Keep RF, Andjelkovic AV. Involvement of Epigenetic Mechanisms and Non-coding RNAs in Blood-Brain Barrier and Neurovascular Unit Injury and Recovery After Stroke. Front Neurosci 2019; 13:864. [PMID: 31543756 PMCID: PMC6732937 DOI: 10.3389/fnins.2019.00864] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/31/2019] [Indexed: 12/13/2022] Open
Abstract
Cessation of blood flow leads to a complex cascade of pathophysiological events at the blood-vascular-parenchymal interface which evolves over time and space, and results in damage to neural cells and edema formation. Cerebral ischemic injury evokes a profound and deleterious upregulation in inflammation and triggers multiple cell death pathways, but it also induces a series of the events associated with regenerative responses, including vascular remodeling, angiogenesis, and neurogenesis. Emerging evidence suggests that epigenetic reprograming could play a pivotal role in ongoing post-stroke neurovascular unit (NVU) changes and recovery. This review summarizes current knowledge about post-stroke recovery processes at the NVU, as well as epigenetic mechanisms and modifiers (e.g., DNA methylation, histone modifying enzymes and microRNAs) associated with stroke injury, and NVU repair. It also discusses novel drug targets and therapeutic strategies for enhancing post-stroke recovery.
Collapse
Affiliation(s)
- Svetlana M Stamatovic
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Chelsea M Phillips
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States
| | | | - Richard F Keep
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Molecular Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Anuska V Andjelkovic
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI, United States
| |
Collapse
|
37
|
Mensching L, Djogo N, Keller C, Rading S, Karsak M. Stable Adult Hippocampal Neurogenesis in Cannabinoid Receptor CB2 Deficient Mice. Int J Mol Sci 2019; 20:ijms20153759. [PMID: 31374821 PMCID: PMC6696320 DOI: 10.3390/ijms20153759] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 12/12/2022] Open
Abstract
The G-protein coupled cannabinoid receptor 2 (CB2) has been implicated in the regulation of adult neurogenesis in the hippocampus. The contribution of CB2 towards basal levels of proliferation and the number of neural progenitors in the subgranular zone (SGZ) of the dentate gyrus, however, remain unclear. We stained hippocampal brain sections of 16- to 17-week-old wildtype and CB2-deficient mice, for neural progenitor and immature neuron markers doublecortin (DCX) and calretinin (CR) and for the proliferation marker Ki67 and quantified the number of positive cells in the SGZ. The quantification revealed that CB2 deficiency neither altered overall cell proliferation nor the size of the DCX+ or DCX and CR double-positive populations in the SGZ compared to control animals. The results indicate that CB2 might not contribute to basal levels of adult neurogenesis in four-month-old healthy mice. CB2 signaling might be more relevant in conditions where adult neurogenesis is dynamically regulated, such as neuroinflammation.
Collapse
Affiliation(s)
- Leonore Mensching
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Nevena Djogo
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Christina Keller
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Sebastian Rading
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Meliha Karsak
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany.
| |
Collapse
|
38
|
Liu W, Kämpfe Nordström C, Danckwardt-Lillieström N, Rask-Andersen H. Human Inner Ear Immune Activity: A Super-Resolution Immunohistochemistry Study. Front Neurol 2019; 10:728. [PMID: 31354608 PMCID: PMC6635812 DOI: 10.3389/fneur.2019.00728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/19/2019] [Indexed: 12/20/2022] Open
Abstract
Background: Like the brain, the human inner ear was long thought to be devoid of immune activity. Only the endolymphatic sac (ES) was known to be endowed with white blood cells that could process antigens and serve as an immunologic defense organ for the entire inner ear. Unexpectedly, the cochlear and vestibular organs, including the eighth cranial nerve, were recently shown to contain macrophages whose functions and implication in ear disease are somewhat undefined. Here, we review recent inner ear findings in man and extend the analyses to the vestibular nerve using super-resolution structured illumination microscopy (SR-SIM). Materials and Methods: Human ESs and cochleae were collected during surgery to treat patients with vestibular schwannoma and life-threatening petro-clival meningioma compressing the brainstem. The ESs and cochleae were placed in fixative, decalcified, and rapidly frozen and cryostat sectioned. Antibodies against ionized calcium-binding adaptor molecule 1-expressing cells (IBA1 cells), laminin β2 and type IV collagen TUJ1, cytokine fractalkine (CX3CL1), toll-like receptor 4 (TLR4), CD68, CD11b, CD4, CD8, the major histocompatibility complex type II (MHCII), and the microglial marker TEME119 were used. Results: IBA1-positive cells were present in the ESs, the cochlea, central and peripheral axons of the cochlear nerve, and the vestibular nerve trunk. IBA1 cells were found in the cochlear lateral wall, spiral limbus, and spiral ganglion. Notable variants of IBA1 cells adhered to neurons with “synapse-like” specializations and cytoplasmic projections. Slender IBA1 cells occasionally protracted into the basal lamina of the Schwann cells and had intimate contact with surrounding axons. Discussion: The human eighth nerve may be under the control of a well-developed macrophage cell system. A small number of CD4+ and CD8+ cells were found in the ES and occasionally in the cochlea, mostly located in the peripheral region of Rosenthal's canal. A neuro-immunologic axis may exist in the human inner ear that could play a role in the protection of the auditory nerve. The implication of the macrophage system during disease, surgical interventions, and cell-based transplantation should be further explored.
Collapse
Affiliation(s)
- Wei Liu
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Charlotta Kämpfe Nordström
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | | | - Helge Rask-Andersen
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| |
Collapse
|
39
|
Basilico B, Cortese B, Ratano P, Angelantonio SD, Ragozzino D. Time-lapse Whole-field Fluorescence Imaging of Microglia ProcessesMotility in Acute Mouse Hippocampal Slices and Analysis. Bio Protoc 2019; 9:e3220. [PMID: 33655009 DOI: 10.21769/bioprotoc.3220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/22/2019] [Accepted: 04/29/2019] [Indexed: 11/02/2022] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS). In the last year, the improvements in the transgenic mouse technologies and imaging techniques have shed light on microglia functions under physiological conditions. Microglia continuously scan the brain parenchyma with their highly motile processes, maintaining tissue homeostasis and participating in neuronal circuits refinement. Here, we describe a protocol that enables us to perform time-lapse imaging of microglial cells in acute hippocampal slices, making image acquisition possible on an electrophysiology rig equipped with a standard imaging system. Using this ex vivo approach, we investigated microglial processes scanning abilities under physiological condition in hippocampus.
Collapse
Affiliation(s)
| | - Barbara Cortese
- CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics, Sapienza University, Rome, Italy
| | - Patrizia Ratano
- Dept of Physiology and Pharmacology, Sapienza University, Rome, Italy.,CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics, Sapienza University, Rome, Italy
| | - Silvia Di Angelantonio
- Dept of Physiology and Pharmacology, Sapienza University, Rome, Italy.,CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics, Sapienza University, Rome, Italy
| | - Davide Ragozzino
- Dept of Physiology and Pharmacology, Sapienza University, Rome, Italy.,CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics, Sapienza University, Rome, Italy
| |
Collapse
|
40
|
Cai B, Seong KJ, Bae SW, Kook MS, Chun C, Lee JH, Choi WS, Jung JY, Kim WJ. Water-Soluble Arginyl–Diosgenin Analog Attenuates Hippocampal Neurogenesis Impairment Through Blocking Microglial Activation Underlying NF-κB and JNK MAPK Signaling in Adult Mice Challenged by LPS. Mol Neurobiol 2019; 56:6218-6238. [DOI: 10.1007/s12035-019-1496-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/15/2019] [Indexed: 12/20/2022]
|
41
|
Tay TL, Carrier M, Tremblay MÈ. Physiology of Microglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:129-148. [PMID: 31583587 DOI: 10.1007/978-981-13-9913-8_6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Microglia constitute the major immune cells that permanently reside in the central nervous system (CNS) alongside neurons and other glial cells. These resident immune cells are critical for proper brain development, actively maintain brain health throughout the lifespan and rapidly adapt their function to the physiological or pathophysiological needs of the organism. Cutting-edge fate mapping and imaging techniques applied to animal models enabled a revolution in our understanding of their roles during normal physiological conditions. Here, we highlight studies that demonstrate the embryonic yolk sac origin of microglia and describe factors, including crosstalk with the periphery and external environment, that regulate their differentiation, homeostasis and function in the context of healthy CNS. The diversity of microglial phenotypes observed across the lifespan, between brain compartments and between sexes is also discussed. Understanding what defines specific microglial phenotypes is critical for the development of innovative therapies to modulate their effector functions and improve clinical outcomes.
Collapse
Affiliation(s)
- Tuan Leng Tay
- Institute of Biology I, University of Freiburg, Hauptstr. 1, 79104, Freiburg, Germany. .,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany. .,Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany.
| | - Micaël Carrier
- Axe Neurosciences, Centre de Recherche du CHU de Québec, 2705, Boulevard Laurier, Québec, QC, G1V 4G2, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, 2705, Boulevard Laurier, Québec, QC, G1V 4G2, Canada.
| |
Collapse
|
42
|
Basilico B, Pagani F, Grimaldi A, Cortese B, Di Angelantonio S, Weinhard L, Gross C, Limatola C, Maggi L, Ragozzino D. Microglia shape presynaptic properties at developing glutamatergic synapses. Glia 2018; 67:53-67. [DOI: 10.1002/glia.23508] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/13/2018] [Accepted: 06/22/2018] [Indexed: 12/30/2022]
Affiliation(s)
| | | | | | - Barbara Cortese
- CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics; Sapienza University; Rome Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- Istituto Italiano di Tecnologia; Rome Italy
| | | | | | - Cristina Limatola
- Pasteur Institute, Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- IRCCS NEUROMED; Via Atinese Pozzilli Italy
| | - Laura Maggi
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- IRCCS NEUROMED; Via Atinese Pozzilli Italy
| |
Collapse
|
43
|
Go J, Park TS, Han GH, Park HY, Ryu YK, Kim YH, Hwang JH, Choi DH, Noh JR, Hwang DY, Kim S, Oh WK, Lee CH, Kim KS. Piperlongumine decreases cognitive impairment and improves hippocampal function in aged mice. Int J Mol Med 2018; 42:1875-1884. [PMID: 30066827 PMCID: PMC6108885 DOI: 10.3892/ijmm.2018.3782] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 07/06/2018] [Indexed: 11/18/2022] Open
Abstract
Piperlongumine (PL), a biologically active compound from the Piper species, has been shown to exert various pharmacological effects in a number of conditions, including tumours, diabetes, pain, psychiatric disorders and neurodegenerative disease. In this study, we evaluated the therapeutic effects of PL on hippocampal function and cognition decline in aged mice. PL (50 mg/kg/day) was intragastrically administrated to 23‑month‑old female C57BL/6J mice for 8 weeks. Novel object recognition and nest building behaviour tests were used to assess cognitive and social functions. Additionally, immunohistochemistry and western blot analysis were performed to examine the effects of PL on the hippocampus. We found that the oral administration of PL significantly improved novel object recognition and nest building behaviour in aged mice. Although neither the percentage area occupied by astrocytes and microglia nor the level of 4‑hydroxynonenal protein, a specific marker of lipid peroxidation, were altered by PL treatment, the phosphorylation levels of N‑methyl‑D‑aspartate receptor subtype 2B (NR2B), calmodulin‑dependent protein kinase II alpha (CaMKIIα) and extracellular signal‑regulated kinase 1/2 (ERK1/2) were markedly increased in the hippocampus of aged mice following the administration of PL. We also found that PL treatment resulted in a CA3‑specific increase in the phosphorylation level of cyclic AMP response element binding protein, which is recognized as a potent marker of neuronal plasticity, learning and memory. Moreover, the number of doublecortin‑positive cells, a specific marker of neurogenesis, was significantly increased following PL treatment in the dentate gyrus of the hippocampus. On the whole, these data demonstrate that PL treatment may be a potential novel approach in the treatment of age‑related cognitive impairment and hippocampal changes.
Collapse
Affiliation(s)
- Jun Go
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
- Department of Biomaterials Science, College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463
| | - Tae-Shin Park
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
| | - Geun-Hee Han
- College of Pharmacy, Seoul National University, Seoul 08826
| | - Hye-Yeon Park
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
| | - Young-Kyoung Ryu
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
| | - Yong-Hoon Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113
| | - Jung Hwan Hwang
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113
| | - Dong-Hee Choi
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
| | - Jung-Ran Noh
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
| | - Dae Youn Hwang
- Department of Biomaterials Science, College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463
| | - Sanghee Kim
- College of Pharmacy, Seoul National University, Seoul 08826
| | - Won Keun Oh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Chul-Ho Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113
| | - Kyoung-Shim Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113
| |
Collapse
|
44
|
Microglia Play an Active Role in Obesity-Associated Cognitive Decline. J Neurosci 2018; 38:8889-8904. [PMID: 30201764 DOI: 10.1523/jneurosci.0789-18.2018] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/26/2018] [Accepted: 08/20/2018] [Indexed: 12/17/2022] Open
Abstract
Obesity affects >600 million people worldwide, a staggering number that appears to be on the rise. One of the lesser known consequences of obesity is its deleterious effects on cognition, which have been well documented across many cognitive domains and age groups. To investigate the cellular mechanisms that underlie obesity-associated cognitive decline, we used diet-induced obesity in male mice and found memory impairments along with reductions in dendritic spines, sites of excitatory synapses, increases in the activation of microglia, the brain's resident immune cells, and increases in synaptic profiles within microglia, in the hippocampus, a brain region linked to cognition. We found that partial knockdown of the receptor for fractalkine, a chemokine that can serve as a "find me" cue for microglia, prevented microglial activation and cognitive decline induced by obesity. Furthermore, we found that pharmacological inhibition of microglial activation in obese mice was associated with prevention of both dendritic spine loss and cognitive degradation. Finally, we observed that pharmacological blockade of microglial phagocytosis lessened obesity-associated cognitive decline. These findings suggest that microglia play an active role in obesity-associated cognitive decline by phagocytosis of synapses that are important for optimal function.SIGNIFICANCE STATEMENT Obesity in humans correlates with reduced cognitive function. To investigate the cellular mechanisms underlying this, we used diet-induced obesity in mice and found impaired performance on cognitive tests of hippocampal function. These deficits were accompanied by reduced numbers of dendritic spines, increased microglial activation, and increased synaptic profiles within microglia. Inhibition of microglial activation by transgenic and pharmacological methods prevented cognitive decline and dendritic spine loss in obese mice. Moreover, pharmacological inhibition of the phagocytic activity of microglia was also sufficient to prevent cognitive degradation. This work suggests that microglia may be responsible for obesity-associated cognitive decline and dendritic spine loss.
Collapse
|
45
|
Fumagalli M, Lombardi M, Gressens P, Verderio C. How to reprogram microglia toward beneficial functions. Glia 2018; 66:2531-2549. [PMID: 30195261 PMCID: PMC6585737 DOI: 10.1002/glia.23484] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
Abstract
Microglia, brain cells of nonneural origin, orchestrate the inflammatory response to diverse insults, including hypoxia/ischemia or maternal/fetal infection in the perinatal brain. Experimental studies have demonstrated the capacity of microglia to recognize pathogens or damaged cells activating a cytotoxic response that can exacerbate brain damage. However, microglia display an enormous plasticity in their responses to injury and may also promote resolution stages of inflammation and tissue regeneration. Despite the critical role of microglia in brain pathologies, the cellular mechanisms that govern the diverse phenotypes of microglia are just beginning to be defined. Here we review emerging strategies to drive microglia toward beneficial functions, selectively reporting the studies which provide insights into molecular mechanisms underlying the phenotypic switch. A variety of approaches have been proposed which rely on microglia treatment with pharmacological agents, cytokines, lipid messengers, or microRNAs, as well on nutritional approaches or therapies with immunomodulatory cells. Analysis of the molecular mechanisms relevant for microglia reprogramming toward pro‐regenerative functions points to a central role of energy metabolism in shaping microglial functions. Manipulation of metabolic pathways may thus provide new therapeutic opportunities to prevent the deleterious effects of inflammatory microglia and to control excessive inflammation in brain disorders.
Collapse
Affiliation(s)
- Marta Fumagalli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, via Balzaretti, 9 -20133, Milan, Italy
| | | | - Pierre Gressens
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 1141 Paris, France.,Centre for the Developing Brain, Department of Perinatal Health and Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, SE1 7EH, United Kingdom
| | - Claudia Verderio
- IRCCS Humanitas, via Manzoni 56, 20089, Rozzano, Italy.,CNR Institute of Neuroscience, via Vanvitelli 32, 20129 Milan, Italy
| |
Collapse
|
46
|
Aguilera G, Colín-González AL, Rangel-López E, Chavarría A, Santamaría A. Redox Signaling, Neuroinflammation, and Neurodegeneration. Antioxid Redox Signal 2018; 28:1626-1651. [PMID: 28467722 DOI: 10.1089/ars.2017.7099] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Production of pro-inflammatory and anti-inflammatory cytokines is part of the defense system that mostly microglia and macrophages display to induce normal signaling to counteract the deleterious actions of invading pathogens in the brain. Also, redox activity in the central nervous system (CNS) constitutes an integral part of the metabolic processes needed by cells to exert their normal molecular and biochemical functions. Under normal conditions, the formation of reactive oxygen and nitrogen species, and the following oxidative activity encounter a healthy balance with immunological responses to preserve cell functions in the brain. However, under different pathological conditions, inflammatory responses recruit pro-oxidant signals and vice versa. The aim of this article is to review the basic concepts about the triggering of inflammatory and oxidative responses in the CNS. Recent Advances: Diverse concurrent toxic pathways are described to provide a solid mechanistic scope for considering intervention at the experimental and clinical levels that are aimed at diminishing the harmful actions of these two contributing factors to nerve cell damage. Critical Issues and Future Directions: The main conclusion supports the existence of a narrow cross-talk between pro-inflammatory and oxidative signals that can lead to neuronal damage and subsequent neurodegeneration. Further investigation about critical pathways crosslinking oxidative stress and inflammation will strength our knowlegde on this topic. Antioxid. Redox Signal. 28, 1626-1651.
Collapse
Affiliation(s)
- Gabriela Aguilera
- 1 Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía , Mexico City, Mexico
| | - Ana Laura Colín-González
- 1 Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía , Mexico City, Mexico
| | - Edgar Rangel-López
- 1 Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía , Mexico City, Mexico
| | - Anahí Chavarría
- 2 Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México , Mexico City, Mexico
| | - Abel Santamaría
- 1 Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía , Mexico City, Mexico
| |
Collapse
|
47
|
New Insights into Microglia-Neuron Interactions: A Neuron's Perspective. Neuroscience 2018; 405:103-117. [PMID: 29753862 DOI: 10.1016/j.neuroscience.2018.04.046] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 04/26/2018] [Accepted: 04/28/2018] [Indexed: 01/16/2023]
Abstract
Microglia are the primary immune cells of the central nervous system. However, recent data indicate that microglia also contribute to diverse physiological and pathophysiological processes that extend beyond immune-related functions and there is a growing interest to understand the mechanisms through which microglia interact with other cells in the brain. In particular, the molecular processes that contribute to microglia-neuron communication in the healthy brain and their role in common brain diseases have been intensively studied during the last decade. In line with this, fate-mapping studies, genetic models and novel pharmacological approaches have revealed the origin of microglial progenitors, demonstrated the role of self-maintaining microglial populations during brain development or in adulthood, and identified the unexpectedly long lifespan of microglia that may profoundly change our view about senescence and age-related human diseases. Despite the exponentially increasing knowledge about microglia, the role of these cells in health and disease is still extremely controversial and the precise molecular targets for intervention are not well defined. This is in part due to the lack of microglia-specific manipulation approaches until very recently and to the high level of complexity of the interactions between microglia and other cells in the brain that occur at different temporal and spatial scales. In this review, we briefly summarize the known physiological roles of microglia-neuron interactions in brain homeostasis and attempt to outline some major directions and challenges of future microglia research.
Collapse
|
48
|
Abstract
Microglia differentiate from progenitors that infiltrate the nascent CNS during early embryonic development. They then remain in this unique immune-privileged environment throughout life. Multiple immune mechanisms, which we collectively refer to as microglial checkpoints, ensure efficient and tightly regulated microglial responses to perturbations in the CNS milieu. Such mechanisms are essential for proper CNS development and optimal physiological function. However, in chronic disease or aging, when a robust immune response is required, such checkpoint mechanisms may limit the ability of microglia to protect the CNS. Here we survey microglial checkpoint mechanisms and their roles in controlling microglial function throughout life and in disease, and discuss how they may be targeted therapeutically.
Collapse
|
49
|
Paolicelli RC, Bergamini G, Rajendran L. Cell-to-cell Communication by Extracellular Vesicles: Focus on Microglia. Neuroscience 2018; 405:148-157. [PMID: 29660443 DOI: 10.1016/j.neuroscience.2018.04.003] [Citation(s) in RCA: 239] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/30/2018] [Accepted: 04/04/2018] [Indexed: 12/20/2022]
Abstract
Extracellular vesicles, including exosomes and microvesicles, are small, nano-to-micrometer vesicles that are released from cells. While initially observed in immune cells and reticulocytes as vesicles meant to remove archaic proteins, now they have been observed in almost all cell types of multicellular organisms. Growing evidence indicates that extracellular vesicles, containing lipids, proteins and RNAs, represent an efficient way to transfer functional cargoes from one cell to another. In the central nervous system, the extensive cross-talk ongoing between neurons and glia, including microglia, the immune cells of the brain, takes advantage of secreted vesicles, which mediate intercellular communication over long range distance. Recent literature supports a critical role for extracellular vesicles in mediating complex and coordinated communication among neurons, astrocytes and microglia, both in the healthy and in the diseased brain. In this review, we focus on the biogenesis and function of microglia-related extracellular vesicles and focus on their putative role in Alzheimer's disease pathology.
Collapse
Affiliation(s)
- Rosa C Paolicelli
- Systems and Cell Biology of Neurodegeneration, IREM - Institute for Regenerative Medicine, University of Zurich, Switzerland.
| | - Giorgio Bergamini
- Preclinical Laboratory for Translational Research into Affective Disorders (PLaTRAD), Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, IREM - Institute for Regenerative Medicine, University of Zurich, Switzerland
| |
Collapse
|
50
|
Histone Deacetylases 1 and 2 Regulate Microglia Function during Development, Homeostasis, and Neurodegeneration in a Context-Dependent Manner. Immunity 2018; 48:514-529.e6. [PMID: 29548672 DOI: 10.1016/j.immuni.2018.02.016] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/21/2017] [Accepted: 02/22/2018] [Indexed: 11/20/2022]
Abstract
Microglia as tissue macrophages contribute to the defense and maintenance of central nervous system (CNS) homeostasis. Little is known about the epigenetic signals controlling microglia function in vivo. We employed constitutive and inducible mutagenesis in microglia to delete two class I histone deacetylases, Hdac1 and Hdac2. Prenatal ablation of Hdac1 and Hdac2 impaired microglial development. Mechanistically, the promoters of pro-apoptotic and cell cycle genes were hyperacetylated in absence of Hdac1 and Hdac2, leading to increased apoptosis and reduced survival. In contrast, Hdac1 and Hdac2 were not required for adult microglia survival during homeostasis. In a mouse model of Alzheimer's disease, deletion of Hdac1 and Hdac2 in microglia, but not in neuroectodermal cells, resulted in a decrease in amyloid load and improved cognitive impairment by enhancing microglial amyloid phagocytosis. Collectively, we report a role for epigenetic factors that differentially affect microglia development, homeostasis, and disease that could potentially be utilized therapeutically.
Collapse
|