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Izadjoo S, Moritz KE, Khayrullina G, Bergman EM, Melvin BM, Stinson MW, Paulson SG, McCormack NM, Anderson KN, Lewis LA, Rotty JD, Burnett BG. Key features of the innate immune response is mediated by the immunoproteasome in microglia. RESEARCH SQUARE 2024:rs.3.rs-4467983. [PMID: 38883799 PMCID: PMC11177974 DOI: 10.21203/rs.3.rs-4467983/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Microglia are the resident immune cells of the central nervous system (CNS). We and others have shown that the inflammatory response of microglia is partially regulated by the immunoproteasome, an inducible form of the proteasome responsible for the generation of major histocompatibility complex (MHC) class I epitopes. While the role of the proteasome in the adaptive immune system is well established, emerging evidence suggests the immunoproteasome may have discrete functions in the innate immune response. Here, we show that inhibiting the immunoproteasome reduces the IFNγ-dependent induction of complement activator C1q, suppresses phagocytosis, and alters the cytokine expression profile in a microglial cell line and microglia derived from human inducible pluripotent stem cells. Moreover, we show that the immunoproteasome regulates the degradation of IκBα, a modulator of NF-κB signaling. Finally, we demonstrate that NADH prevents induction of the immunoproteasome, representing a potential pathway to suppress immunoproteasome-dependent immune responses.
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2
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Pandya VA, Patani R. The role of glial cells in amyotrophic lateral sclerosis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:381-450. [PMID: 38802179 DOI: 10.1016/bs.irn.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) has traditionally been considered a neuron-centric disease. This view is now outdated, with increasing recognition of cell autonomous and non-cell autonomous contributions of central and peripheral nervous system glia to ALS pathomechanisms. With glial research rapidly accelerating, we comprehensively interrogate the roles of astrocytes, microglia, oligodendrocytes, ependymal cells, Schwann cells and satellite glia in nervous system physiology and ALS-associated pathology. Moreover, we highlight the inter-glial, glial-neuronal and inter-system polylogue which constitutes the healthy nervous system and destabilises in disease. We also propose classification based on function for complex glial reactive phenotypes and discuss the pre-requisite for integrative modelling to advance translation. Given the paucity of life-enhancing therapies currently available for ALS patients, we discuss the promising potential of harnessing glia in driving ALS therapeutic discovery.
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Affiliation(s)
- Virenkumar A Pandya
- University College London Medical School, London, United Kingdom; The Francis Crick Institute, London, United Kingdom.
| | - Rickie Patani
- The Francis Crick Institute, London, United Kingdom; Department of Neuromuscular Diseases, University College London Queen Square Institute of Neurology, Queen Square, London, United Kingdom.
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3
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Aroniadou-Anderjaska V, Figueiredo TH, de Araujo Furtado M, Pidoplichko VI, Braga MFM. Mechanisms of Organophosphate Toxicity and the Role of Acetylcholinesterase Inhibition. TOXICS 2023; 11:866. [PMID: 37888716 PMCID: PMC10611379 DOI: 10.3390/toxics11100866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/11/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023]
Abstract
Organophosphorus compounds (OPs) have applications in agriculture (e.g., pesticides), industry (e.g., flame retardants), and chemical warfare (nerve agents). In high doses or chronic exposure, they can be toxic or lethal. The primary mechanism, common among all OPs, that initiates their toxic effects is the inhibition of acetylcholinesterase. In acute OP exposure, the subsequent surge of acetylcholine in cholinergic synapses causes a peripheral cholinergic crisis and status epilepticus (SE), either of which can lead to death. If death is averted without effective seizure control, long-term brain damage ensues. This review describes the mechanisms by which elevated acetylcholine can cause respiratory failure and trigger SE; the role of the amygdala in seizure initiation; the role of M1 muscarinic receptors in the early stages of SE; the neurotoxic pathways activated by SE (excitotoxicity/Ca++ overload/oxidative stress, neuroinflammation); and neurotoxic mechanisms linked to low-dose, chronic exposure (Ca++ dyshomeostasis/oxidative stress, inflammation), which do not depend on SE and do not necessarily involve acetylcholinesterase inhibition. The evidence so far indicates that brain damage from acute OP exposure is a direct result of SE, while the neurotoxic mechanisms activated by low-dose chronic exposure are independent of SE and may not be associated with acetylcholinesterase inhibition.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Taiza H. Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (V.A.-A.); (V.I.P.)
| | - Marcio de Araujo Furtado
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (V.A.-A.); (V.I.P.)
| | - Volodymyr I. Pidoplichko
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (V.A.-A.); (V.I.P.)
| | - Maria F. M. Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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4
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Lana D, Branca JJV, Delfino G, Giovannini MG, Casamenti F, Nardiello P, Bucciantini M, Stefani M, Zach P, Zecchi-Orlandini S, Nosi D. Morphofunctional Investigation in a Transgenic Mouse Model of Alzheimer's Disease: Non-Reactive Astrocytes Are Involved in Aβ Load and Reactive Astrocytes in Plaque Build-Up. Cells 2023; 12:2258. [PMID: 37759482 PMCID: PMC10526848 DOI: 10.3390/cells12182258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
The term neuroinflammation defines the reactions of astrocytes and microglia to alterations in homeostasis in the diseased central nervous system (CNS), the exacerbation of which contributes to the neurodegenerative effects of Alzheimer's disease (AD). Local environmental conditions, such as the presence of proinflammatory molecules, mechanical properties of the extracellular matrix (ECM), and local cell-cell interactions, are determinants of glial cell phenotypes. In AD, the load of the cytotoxic/proinflammatory amyloid β (Aβ) peptide is a microenvironmental component increasingly growing in the CNS, imposing time-evolving challenges on resident cells. This study aimed to investigate the temporal and spatial variations of the effects produced by this process on astrocytes and microglia, either directly or by interfering in their interactions. Ex vivo confocal analyses of hippocampal sections from the mouse model TgCRND8 at different ages have shown that overproduction of Aβ peptide induced early and time-persistent disassembly of functional astroglial syncytium and promoted a senile phenotype of reactive microglia, hindering Aβ clearance. In the late stages of the disease, these patterns were altered in the presence of Aβ-plaques, surrounded by typically reactive astrocytes and microglia. Morphofunctional characterization of peri-plaque gliosis revealed a direct contribution of astrocytes in plaque buildup that might result in shielding Aβ-peptide cytotoxicity and, as a side effect, in exacerbating neuroinflammation.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, University of Florence, 50134 Florence, Italy; (D.L.); (M.G.G.)
| | - Jacopo Junio Valerio Branca
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (J.J.V.B.); (S.Z.-O.)
| | - Giovanni Delfino
- Department of Biology, University of Florence, 50121 Florence, Italy;
| | - Maria Grazia Giovannini
- Department of Health Sciences, University of Florence, 50134 Florence, Italy; (D.L.); (M.G.G.)
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50134 Florence, Italy;
| | - Pamela Nardiello
- General Laboratory, Careggi University Hospital, 50134 Florence, Italy;
| | - Monica Bucciantini
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (M.B.); (M.S.)
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (M.B.); (M.S.)
| | - Petr Zach
- Department of Anatomy, Third Faculty of Medicine, Charles University, 100 00 Prague, Czech Republic;
| | - Sandra Zecchi-Orlandini
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (J.J.V.B.); (S.Z.-O.)
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (J.J.V.B.); (S.Z.-O.)
- DMSC Imaging Platform, 50134 Florence, Italy
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5
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Lana D, Magni G, Landucci E, Wenk GL, Pellegrini-Giampietro DE, Giovannini MG. Phenomic Microglia Diversity as a Druggable Target in the Hippocampus in Neurodegenerative Diseases. Int J Mol Sci 2023; 24:13668. [PMID: 37761971 PMCID: PMC10531074 DOI: 10.3390/ijms241813668] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
Phenomics, the complexity of microglia phenotypes and their related functions compels the continuous study of microglia in disease animal models to find druggable targets for neurodegenerative disorders. Activation of microglia was long considered detrimental for neuron survival, but more recently it has become apparent that the real scenario of microglia morphofunctional diversity is far more complex. In this review, we discuss the recent literature on the alterations in microglia phenomics in the hippocampus of animal models of normal brain aging, acute neuroinflammation, ischemia, and neurodegenerative disorders, such as AD. Microglia undergo phenomic changes consisting of transcriptional, functional, and morphological changes that transform them into cells with different properties and functions. The classical subdivision of microglia into M1 and M2, two different, all-or-nothing states is too simplistic, and does not correspond to the variety of phenotypes recently discovered in the brain. We will discuss the phenomic modifications of microglia focusing not only on the differences in microglia reactivity in the diverse models of neurodegenerative disorders, but also among different areas of the brain. For instance, in contiguous and highly interconnected regions of the rat hippocampus, microglia show a differential, finely regulated, and region-specific reactivity, demonstrating that microglia responses are not uniform, but vary significantly from area to area in response to insults. It is of great interest to verify whether the differences in microglia reactivity may explain the differential susceptibility of different brain areas to insults, and particularly the higher sensitivity of CA1 pyramidal neurons to inflammatory stimuli. Understanding the spatiotemporal heterogeneity of microglia phenomics in health and disease is of paramount importance to find new druggable targets for the development of novel microglia-targeted therapies in different CNS disorders. This will allow interventions in three different ways: (i) by suppressing the pro-inflammatory properties of microglia to limit the deleterious effect of their activation; (ii) by modulating microglia phenotypic change to favor anti-inflammatory properties; (iii) by influencing microglia priming early in the disease process.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Giada Magni
- Institute of Applied Physics “Nello Carrara”, National Research Council (IFAC-CNR), Via Madonna del Piano 10, 50019 Florence, Italy;
| | - Elisa Landucci
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Gary L. Wenk
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA;
| | - Domenico Edoardo Pellegrini-Giampietro
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
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6
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Cheng J, Wang W, Xia Y, Li Y, Jia J, Xiao G. Regulators of phagocytosis as pharmacologic targets for stroke treatment. Front Pharmacol 2023; 14:1122527. [PMID: 37601043 PMCID: PMC10433754 DOI: 10.3389/fphar.2023.1122527] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
Stroke, including ischemic and hemorrhagic stroke, causes massive cell death in the brain, which is followed by secondary inflammatory injury initiated by disease-associated molecular patterns released from dead cells. Phagocytosis, a cellular process of engulfment and digestion of dead cells, promotes the resolution of inflammation and repair following stroke. However, professional or non-professional phagocytes also phagocytose stressed but viable cells in the brain or excessively phagocytose myelin sheaths or prune synapses, consequently exacerbating brain injury and impairing repair following stroke. Phagocytosis includes the smell, eating and digestion phases. Notably, efficient phagocytosis critically depends on phagocyte capacity to take up dead cells continually due to the limited number of phagocytes vs. dead cells after injury. Moreover, phenotypic polarization of phagocytes occurring after phagocytosis is also essential to the proresolving and prorepair properties of phagocytosis. Much has been learned about the molecular signals and regulatory mechanisms governing the sense and recognition of dead cells by phagocytes during the smell and eating phase following stroke. However, some key areas remain extremely understudied, including the mechanisms involved in digestion regulation, continual phagocytosis and phagocytosis-induced phenotypic switching following stroke. Here, we summarize new discoveries related to the molecular mechanisms and multifaceted effects of phagocytosis on brain injury and repair following stroke and highlight the knowledge gaps in poststroke phagocytosis. We suggest that advancing the understanding of poststroke phagocytosis will help identify more biological targets for stroke treatment.
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Affiliation(s)
- Jian Cheng
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei Wang
- Department of Pharmacy, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yiqing Xia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Yi Li
- Academy of Pharmacy, Xi’an Jiaotong-Liverpool University, Suzhou, China
| | - Jia Jia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Guodong Xiao
- Suzhou Clinical Research Center of Neurological Disease, Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, China
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7
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Zohar K, Lezmi E, Reichert F, Eliyahu T, Rotshenker S, Weinstock M, Linial M. Coordinated Transcriptional Waves Define the Inflammatory Response of Primary Microglial Culture. Int J Mol Sci 2023; 24:10928. [PMID: 37446105 DOI: 10.3390/ijms241310928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
The primary role of microglia is to maintain homeostasis by effectively responding to various disturbances. Activation of transcriptional programs determines the microglia's response to external stimuli. In this study, we stimulated murine neonatal microglial cells with benzoyl ATP (bzATP) and lipopolysaccharide (LPS), and monitored their ability to release pro-inflammatory cytokines. When cells are exposed to bzATP, a purinergic receptor agonist, a short-lived wave of transcriptional changes, occurs. However, only combining bzATP and LPS led to a sustainable and robust response. The transcriptional profile is dominated by induced cytokines (e.g., IL-1α and IL-1β), chemokines, and their membrane receptors. Several abundant long noncoding RNAs (lncRNAs) are induced by bzATP/LPS, including Ptgs2os2, Bc1, and Morrbid, that function in inflammation and cytokine production. Analyzing the observed changes through TNF (Tumor necrosis factor) and NF-κB (nuclear factor kappa light chain enhancer of activated B cells) pathways confirmed that neonatal glial cells exhibit a distinctive expression program in which inflammatory-related genes are upregulated by orders of magnitude. The observed capacity of the microglial culture to activate a robust inflammatory response is useful for studying neurons under stress, brain injury, and aging. We propose the use of a primary neonatal microglia culture as a responsive in vitro model for testing drugs that may interact with inflammatory signaling and the lncRNA regulatory network.
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Affiliation(s)
- Keren Zohar
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Elyad Lezmi
- Department of Genetics, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Fanny Reichert
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91121, Israel
| | - Tsiona Eliyahu
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shlomo Rotshenker
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91121, Israel
| | - Marta Weinstock
- Institute of Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91121, Israel
| | - Michal Linial
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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8
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Gudkov SV, Burmistrov DE, Kondakova EV, Sarimov RM, Yarkov RS, Franceschi C, Vedunova MV. An emerging role of astrocytes in aging/neuroinflammation and gut-brain axis with consequences on sleep and sleep disorders. Ageing Res Rev 2023; 83:101775. [PMID: 36334910 DOI: 10.1016/j.arr.2022.101775] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 10/05/2022] [Accepted: 10/30/2022] [Indexed: 11/18/2022]
Abstract
Understanding the role of astrocytes in the central nervous system has changed dramatically over the last decade. The accumulating findings indicate that glial cells are involved not only in the maintenance of metabolic and ionic homeostasis and in the implementation of trophic functions but also in cognitive functions and information processing in the brain. Currently, there are some controversies regarding the role of astrocytes in complex processes such as aging of the nervous system and the pathogenesis of age-related neurodegenerative diseases. Many findings confirm the important functional role of astrocytes in age-related brain changes, including sleep disturbance and the development of neurodegenerative diseases and particularly Alzheimer's disease. Until recent years, neurobiological research has focused mainly on neuron-glial interactions, in which individual astrocytes locally modulate neuronal activity and communication between neurons. The review considers the role of astrocytes in the physiology of sleep and as an important "player" in the development of neurodegenerative diseases. In addition, the features of the astrocytic network reorganization during aging are discussed.
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Affiliation(s)
- Sergey V Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia; Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Dmitriy E Burmistrov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Elena V Kondakova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Ruslan M Sarimov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Roman S Yarkov
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Claudio Franceschi
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Maria V Vedunova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
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9
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The Role of Aldose Reductase in Beta-Amyloid-Induced Microglia Activation. Int J Mol Sci 2022; 23:ijms232315088. [PMID: 36499422 PMCID: PMC9739496 DOI: 10.3390/ijms232315088] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
The occurrence of Alzheimer's disease has been associated with the accumulation of beta-amyloid (β-amyloid) plaques. These plaques activate microglia to secrete inflammatory molecules, which damage neurons in the brain. Thus, understanding the underlying mechanism of microglia activation can provide a therapeutic strategy for alleviating microglia-induced neuroinflammation. The aldose reductase (AR) enzyme catalyzes the reduction of glucose to sorbitol in the polyol pathway. In addition to mediating diabetic complications in hyperglycemic environments, AR also helps regulate inflammation in microglia. However, little is known about the role of AR in β-amyloid-induced inflammation in microglia and subsequent neuronal death. In this study, we confirmed that AR inhibition attenuates increased β-amyloid-induced reactive oxygen species and tumor necrosis factor α secretion by suppressing ERK signaling in BV2 cells. In addition, we are the first to report that AR inhibition reduced the phagocytotic capability and cell migration of BV2 cells in response to β-amyloid. To further investigate the protective role of the AR inhibitor sorbinil in neurons, we co-cultured β-amyloid-induced microglia with stem cell-induced neurons. sorbinil ameliorated neuronal damage in both cells in the co-culture system. In summary, our findings reveal AR regulation of microglia activation as a novel therapeutic target for Alzheimer's disease.
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10
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Margeta MA, Yin Z, Madore C, Pitts KM, Letcher SM, Tang J, Jiang S, Gauthier CD, Silveira SR, Schroeder CM, Lad EM, Proia AD, Tanzi RE, Holtzman DM, Krasemann S, Chen DF, Butovsky O. Apolipoprotein E4 impairs the response of neurodegenerative retinal microglia and prevents neuronal loss in glaucoma. Immunity 2022; 55:1627-1644.e7. [PMID: 35977543 PMCID: PMC9488669 DOI: 10.1016/j.immuni.2022.07.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 05/09/2022] [Accepted: 07/18/2022] [Indexed: 12/27/2022]
Abstract
The apolipoprotein E4 (APOE4) allele is associated with an increased risk of Alzheimer disease and a decreased risk of glaucoma, but the underlying mechanisms remain poorly understood. Here, we found that in two mouse glaucoma models, microglia transitioned to a neurodegenerative phenotype characterized by upregulation of Apoe and Lgals3 (Galectin-3), which were also upregulated in human glaucomatous retinas. Mice with targeted deletion of Apoe in microglia or carrying the human APOE4 allele were protected from retinal ganglion cell (RGC) loss, despite elevated intraocular pressure (IOP). Similarly to Apoe-/- retinal microglia, APOE4-expressing microglia did not upregulate neurodegeneration-associated genes, including Lgals3, following IOP elevation. Genetic and pharmacologic targeting of Galectin-3 ameliorated RGC degeneration, and Galectin-3 expression was attenuated in human APOE4 glaucoma samples. These results demonstrate that impaired activation of APOE4 microglia is protective in glaucoma and that the APOE-Galectin-3 signaling can be targeted to treat this blinding disease.
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Affiliation(s)
- Milica A Margeta
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Zhuoran Yin
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charlotte Madore
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000 Bordeaux, France
| | - Kristen M Pitts
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Sophia M Letcher
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Jing Tang
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Shuhong Jiang
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Christian D Gauthier
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sebastian R Silveira
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Caitlin M Schroeder
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eleonora M Lad
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Alan D Proia
- Department of Pathology, Duke University Medical Center, Durham, NC, USA; Department of Pathology, Campbell University School of Osteopathic Medicine, Lillington, NC, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, Mass General Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer Disease Research Center, Washington University, St. Louis, MO, USA
| | - Susanne Krasemann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dong Feng Chen
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Evergrande Center for Immunologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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11
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Chen W, Zhang Y, Zhai X, Xie L, Guo Y, Chen C, Li Y, Wang F, Zhu Z, Zheng L, Wan J, Li P. Microglial phagocytosis and regulatory mechanisms after stroke. J Cereb Blood Flow Metab 2022; 42:1579-1596. [PMID: 35491825 PMCID: PMC9441720 DOI: 10.1177/0271678x221098841] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Stroke, including ischemic stroke and hemorrhagic stroke can cause massive neuronal death and disruption of brain structure, which is followed by secondary inflammatory injury initiated by pro-inflammatory molecules and cellular debris. Phagocytic clearance of cellular debris by microglia, the brain's scavenger cells, is pivotal for neuroinflammation resolution and neurorestoration. However, microglia can also exacerbate neuronal loss by phagocytosing stressed-but-viable neurons in the penumbra, thereby expanding the injury area and hindering neurofunctional recovery. Microglia constantly patrol the central nervous system using their processes to scour the cellular environment and start or cease the phagocytosis progress depending on the "eat me" or "don't eat me'' signals on cellular surface. An optimal immune response requires a delicate balance between different phenotypic states to regulate neuro-inflammation and facilitate reconstruction after stroke. Here, we examine the literature and discuss the molecular mechanisms and cellular pathways regulating microglial phagocytosis, their resulting effects in brain injury and neural regeneration, as well as the potential therapeutic targets that might modulate microglial phagocytic activity to improve neurological function after stroke.
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Affiliation(s)
- Weijie Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yueman Zhang
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaozhu Zhai
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lv Xie
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunlu Guo
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fajun Wang
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ziyu Zhu
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Zheng
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jieqing Wan
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peiying Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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12
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Osorio C, Sfera A, Anton JJ, Thomas KG, Andronescu CV, Li E, Yahia RW, Avalos AG, Kozlakidis Z. Virus-Induced Membrane Fusion in Neurodegenerative Disorders. Front Cell Infect Microbiol 2022; 12:845580. [PMID: 35531328 PMCID: PMC9070112 DOI: 10.3389/fcimb.2022.845580] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/01/2022] [Indexed: 12/15/2022] Open
Abstract
A growing body of epidemiological and research data has associated neurotropic viruses with accelerated brain aging and increased risk of neurodegenerative disorders. Many viruses replicate optimally in senescent cells, as they offer a hospitable microenvironment with persistently elevated cytosolic calcium, abundant intracellular iron, and low interferon type I. As cell-cell fusion is a major driver of cellular senescence, many viruses have developed the ability to promote this phenotype by forming syncytia. Cell-cell fusion is associated with immunosuppression mediated by phosphatidylserine externalization that enable viruses to evade host defenses. In hosts, virus-induced immune dysfunction and premature cellular senescence may predispose to neurodegenerative disorders. This concept is supported by novel studies that found postinfectious cognitive dysfunction in several viral illnesses, including human immunodeficiency virus-1, herpes simplex virus-1, and SARS-CoV-2. Virus-induced pathological syncytia may provide a unified framework for conceptualizing neuronal cell cycle reentry, aneuploidy, somatic mosaicism, viral spreading of pathological Tau and elimination of viable synapses and neurons by neurotoxic astrocytes and microglia. In this narrative review, we take a closer look at cell-cell fusion and vesicular merger in the pathogenesis of neurodegenerative disorders. We present a "decentralized" information processing model that conceptualizes neurodegeneration as a systemic illness, triggered by cytoskeletal pathology. We also discuss strategies for reversing cell-cell fusion, including, TMEM16F inhibitors, calcium channel blockers, senolytics, and tubulin stabilizing agents. Finally, going beyond neurodegeneration, we examine the potential benefit of harnessing fusion as a therapeutic strategy in regenerative medicine.
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Affiliation(s)
- Carolina Osorio
- Department of Psychiatry, Loma Linda University, Loma Linda, CA, United States
| | - Adonis Sfera
- Department of Psychiatry, Loma Linda University, Loma Linda, CA, United States
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Jonathan J. Anton
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Karina G. Thomas
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Christina V. Andronescu
- Medical Anthropology – Department of Anthropology, Stanford University, Stanford, CA, United States
| | - Erica Li
- School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Rayan W. Yahia
- School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Andrea García Avalos
- Universidad Nacional Autónoma de México (UNAM), Facultad de Medicina Campus, Ciudad de Mexico, Mexico
| | - Zisis Kozlakidis
- International Agency for Research on Cancer (IARC), Lyon, France
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13
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Machlovi SI, Neuner SM, Hemmer BM, Khan R, Liu Y, Huang M, Zhu JD, Castellano JM, Cai D, Marcora E, Goate AM. APOE4 confers transcriptomic and functional alterations to primary mouse microglia. Neurobiol Dis 2022; 164:105615. [PMID: 35031484 PMCID: PMC8934202 DOI: 10.1016/j.nbd.2022.105615] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 12/09/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Common genetic variants in more than forty loci modulate risk for Alzheimer's disease (AD). AD risk alleles are enriched within enhancers active in myeloid cells, suggesting that microglia, the brain-resident macrophages, may play a key role in the etiology of AD. A major genetic risk factor for AD is Apolipoprotein E (APOE) genotype, with the ε4/ε4 (E4) genotype increasing risk for AD by approximately 15 fold compared to the most common ε3/ε3 (E3) genotype. However, the impact of APOE genotype on microglial function has not been thoroughly investigated. To address this, we cultured primary microglia from mice in which both alleles of the mouse Apoe gene have been humanized to encode either human APOE ε3 or APOE ε4. Relative to E3 microglia, E4 microglia exhibit altered morphology, increased endolysosomal mass, increased cytokine/chemokine production, and increased lipid and lipid droplet accumulation at baseline. These changes were accompanied by decreased translation and increased phosphorylation of eIF2ɑ and eIF2ɑ-kinases that participate in the integrated stress response, suggesting that E4 genotype leads to elevated levels of cellular stress in microglia relative to E3 genotype. Using live-cell imaging and flow cytometry, we also show that E4 microglia exhibited increased phagocytic uptake of myelin and other substrates compared to E3 microglia. While transcriptomic profiling of myelin-challenged microglia revealed a largely overlapping response profile across genotypes, differential enrichment of genes in interferon signaling, extracellular matrix and translation-related pathways was identified in E4 versus E3 microglia both at baseline and following myelin challenge. Together, our results suggest E4 genotype confers several important functional alterations to microglia even prior to myelin challenge, providing insight into the molecular and cellular mechanisms by which APOE4 may increase risk for AD.
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Affiliation(s)
- Saima I Machlovi
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sarah M Neuner
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Brittany M Hemmer
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Riana Khan
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yiyuan Liu
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Min Huang
- James J Peters VA Medical Center, Research & Development, Bronx, NY, USA; Department of Neurology, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jeffrey D Zhu
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joseph M Castellano
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Neurology, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dongming Cai
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; James J Peters VA Medical Center, Research & Development, Bronx, NY, USA; Department of Neurology, New York, NY, USA; Alzheimer Disease Research Center, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Edoardo Marcora
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alison M Goate
- Ronald M. Loeb Center for Alzheimer's Disease, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, USA; Department of Genetics and Genomic Sciences, New York, NY, USA; Department of Neurology, New York, NY, USA; Alzheimer Disease Research Center, New York, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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14
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Rodríguez AM, Rodríguez J, Giambartolomei GH. Microglia at the Crossroads of Pathogen-Induced Neuroinflammation. ASN Neuro 2022; 14:17590914221104566. [PMID: 35635133 PMCID: PMC9158411 DOI: 10.1177/17590914221104566] [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] [Indexed: 01/22/2023] Open
Abstract
Microglia are the resident tissue macrophages of the central nervous system (CNS). Recent findings point out that in the steady state the major role of microglia, is to instruct and regulate the correct function of the neuronal networks and different components of the neurovascular unit in the adult CNS, while providing immune surveillance. Paradoxically, during CNS infection immune activation of microglia generates an inflammatory milieu that contributes to the clearance of the pathogen but can, in the process, harm nearby cells of CNS. Most of the knowledge about the harmful effects of activated microglia on CNS has arisen from studies on neurodegenerative diseases. In this review we will focus on the beneficial role and detrimental functions of microglial cells on the neighboring cells of the CNS upon infection.
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Affiliation(s)
- Ana María Rodríguez
- Instituto de Inmunología, Genética y Metabolismo (INIGEM). CONICET. Facultad de Farmacia y Bioquímica, 28196Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Julia Rodríguez
- Instituto de Inmunología, Genética y Metabolismo (INIGEM). CONICET. Facultad de Farmacia y Bioquímica, 28196Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Guillermo Hernán Giambartolomei
- Instituto de Inmunología, Genética y Metabolismo (INIGEM). CONICET. Facultad de Farmacia y Bioquímica, 28196Universidad de Buenos Aires, Buenos Aires, Argentina
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15
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Wyatt-Johnson SK, Sommer AL, Shim KY, Brewster AL. Suppression of Microgliosis With the Colony-Stimulating Factor 1 Receptor Inhibitor PLX3397 Does Not Attenuate Memory Defects During Epileptogenesis in the Rat. Front Neurol 2021; 12:651096. [PMID: 34149593 PMCID: PMC8209304 DOI: 10.3389/fneur.2021.651096] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/11/2021] [Indexed: 12/03/2022] Open
Abstract
Events of status epilepticus (SE) trigger the development of temporal lobe epilepsy (TLE), a type of focal epilepsy that is commonly drug-resistant and is highly comorbid with cognitive deficits. While SE-induced hippocampal injury, accompanied by gliosis and neuronal loss, typically disrupts cognitive functions resulting in memory defects, it is not definitively known how. Our previous studies revealed extensive hippocampal microgliosis that peaked between 2 and 3 weeks after SE and paralleled the development of cognitive impairments, suggesting a role for reactive microglia in this pathophysiology. Microglial survival and proliferation are regulated by the colony-stimulating factor 1 receptor (CSF1R). The CSF1R inhibitor PLX3397 has been shown to reduce/deplete microglial populations and improve cognitive performance in models of neurodegenerative disorders. Therefore, we hypothesized that suppression of microgliosis with PLX3397 during epileptogenesis may attenuate the hippocampal-dependent spatial learning and memory deficits in the rat pilocarpine model of SE and acquired TLE. Different groups of control and SE rats were fed standard chow (SC) or chow with PLX3397 starting immediately after SE and for 3 weeks. Novel object recognition (NOR) and Barnes maze (BM) were performed to determine memory function between 2 and 3 weeks after SE. Then microglial populations were assessed using immunohistochemistry. Control rats fed with either SC or PLX3397 performed similarly in both NOR and BM tests, differentiating novel vs. familiar objects in NOR, and rapidly learning the location of the hidden platform in BM. In contrast, both SE groups (SC and PLX3397) showed significant deficits in both NOR and BM tests compared to controls. Both PLX3397-treated control and SE groups had significantly decreased numbers of microglia in the hippocampus (60%) compared to those in SC. In parallel, we found that PLX3397 treatment also reduced SE-induced hippocampal astrogliosis. Thus, despite drastic reductions in microglial cells, memory was unaffected in the PLX3397-treated groups compared to those in SC, suggesting that remaining microglia may be sufficient to help maintain hippocampal functions. In sum, PLX3397 did not improve or worsen the memory deficits in rats that sustained pilocarpine-induced SE. Further research is required to determine whether microglia play a role in cognitive decline during epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Alexandra L Sommer
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Kevin Y Shim
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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16
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The Microbiota-Gut-Brain Axis and Alzheimer Disease. From Dysbiosis to Neurodegeneration: Focus on the Central Nervous System Glial Cells. J Clin Med 2021; 10:jcm10112358. [PMID: 34072107 PMCID: PMC8199461 DOI: 10.3390/jcm10112358] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023] Open
Abstract
The microbiota-gut system can be thought of as a single unit that interacts with the brain via the "two-way" microbiota-gut-brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. In the present review will be described the modalities through which the microbiota and gut control each other, and the main microbiota products conditioning both local and brain homeostasis. Much evidence has accumulated over the past decade in favor of a significant association between dysbiosis, neuroinflammation and neurodegeneration. Presently, the pathogenetic mechanisms triggered by molecules produced by the altered microbiota, also responsible for the onset and evolution of Alzheimer disease, will be described. Our attention will be focused on the role of astrocytes and microglia. Numerous studies have progressively demonstrated how these glial cells are important to ensure an adequate environment for neuronal activity in healthy conditions. Furthermore, it is becoming evident how both cell types can mediate the onset of neuroinflammation and lead to neurodegeneration when subjected to pathological stimuli. Based on this information, the role of the major microbiota products in shifting the activation profiles of astrocytes and microglia from a healthy to a diseased state will be discussed, focusing on Alzheimer disease pathogenesis.
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17
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Nosi D, Lana D, Giovannini MG, Delfino G, Zecchi-Orlandini S. Neuroinflammation: Integrated Nervous Tissue Response through Intercellular Interactions at the "Whole System" Scale. Cells 2021; 10:1195. [PMID: 34068375 PMCID: PMC8153304 DOI: 10.3390/cells10051195] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
Different cell populations in the nervous tissue establish numerous, heterotypic interactions and perform specific, frequently intersecting activities devoted to the maintenance of homeostasis. Microglia and astrocytes, respectively the immune and the "housekeeper" cells of nervous tissue, play a key role in neurodegenerative diseases. Alterations of tissue homeostasis trigger neuroinflammation, a collective dynamic response of glial cells. Reactive astrocytes and microglia express various functional phenotypes, ranging from anti-inflammatory to pro-inflammatory. Chronic neuroinflammation is characterized by a gradual shift of astroglial and microglial phenotypes from anti-inflammatory to pro-inflammatory, switching their activities from cytoprotective to cytotoxic. In this scenario, the different cell populations reciprocally modulate their phenotypes through intense, reverberating signaling. Current evidence suggests that heterotypic interactions are links in an intricate network of mutual influences and interdependencies connecting all cell types in the nervous system. In this view, activation, modulation, as well as outcomes of neuroinflammation, should be ascribed to the nervous tissue as a whole. While the need remains of identifying further links in this network, a step back to rethink our view of neuroinflammation in the light of the "whole system" scale, could help us to understand some of its most controversial and puzzling features.
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Affiliation(s)
- Daniele Nosi
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
| | - Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Giovanni Delfino
- Department of Biology, University of Florence, Via Madonna del Piano, 6, 50019 Sesto Fiorentino, Florence, Italy;
| | - Sandra Zecchi-Orlandini
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
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18
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Duggan MR, Parikh V. Microglia and modifiable life factors: Potential contributions to cognitive resilience in aging. Behav Brain Res 2021; 405:113207. [PMID: 33640394 PMCID: PMC8005490 DOI: 10.1016/j.bbr.2021.113207] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/27/2021] [Accepted: 02/20/2021] [Indexed: 02/08/2023]
Abstract
Given the increasing prevalence of age-related cognitive decline, it is relevant to consider the factors and mechanisms that might facilitate an individual's resiliency to such deficits. Growing evidence suggests a preeminent role of microglia, the prime mediator of innate immunity within the central nervous system. Human and animal investigations suggest aberrant microglial functioning and neuroinflammation are not only characteristic of the aged brain, but also might contribute to age-related dementia and Alzheimer's Disease. Conversely, accumulating data suggest that modifiable lifestyle factors (MLFs), such as healthy diet, exercise and cognitive engagement, can reliably afford cognitive benefits by potentially suppressing inflammation in the aging brain. The present review highlights recent advances in our understanding of the role for microglia in maintaining brain homeostasis and cognitive functioning in aging. Moreover, we propose an integrated, mechanistic model that postulates an individual's resiliency to cognitive decline afforded by MLFs might be mediated by the mitigation of aberrant microglia activation in aging, and subsequent suppression of neuroinflammation.
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Affiliation(s)
- Michael R Duggan
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, United States
| | - Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, United States.
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19
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Raiders S, Han T, Scott-Hewitt N, Kucenas S, Lew D, Logan MA, Singhvi A. Engulfed by Glia: Glial Pruning in Development, Function, and Injury across Species. J Neurosci 2021; 41:823-833. [PMID: 33468571 PMCID: PMC7880271 DOI: 10.1523/jneurosci.1660-20.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Phagocytic activity of glial cells is essential for proper nervous system sculpting, maintenance of circuitry, and long-term brain health. Glial engulfment of apoptotic cells and superfluous connections ensures that neuronal connections are appropriately refined, while clearance of damaged projections and neurotoxic proteins in the mature brain protects against inflammatory insults. Comparative work across species and cell types in recent years highlights the striking conservation of pathways that govern glial engulfment. Many signaling cascades used during developmental pruning are re-employed in the mature brain to "fine tune" synaptic architecture and even clear neuronal debris following traumatic events. Moreover, the neuron-glia signaling events required to trigger and perform phagocytic responses are impressively conserved between invertebrates and vertebrates. This review offers a compare-and-contrast portrayal of recent findings that underscore the value of investigating glial engulfment mechanisms in a wide range of species and contexts.
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Affiliation(s)
- Stephan Raiders
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
| | - Taeho Han
- UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, California 94158
| | - Nicole Scott-Hewitt
- F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Boston, Massachusetts 02115
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Deborah Lew
- Department of Biological Sciences, Fordham University, Bronx, New York 10458
| | - Mary A Logan
- Jungers Center, Department of Neurology, Oregon Health and Science University, Portland, Oregon 97239
| | - Aakanksha Singhvi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
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20
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Xin D, Li T, Chu X, Ke H, Liu D, Wang Z. MSCs-extracellular vesicles attenuated neuroinflammation, synapse damage and microglial phagocytosis after hypoxia-ischemia injury by preventing osteopontin expression. Pharmacol Res 2021; 164:105322. [PMID: 33279596 DOI: 10.1016/j.phrs.2020.105322] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 10/26/2020] [Accepted: 11/24/2020] [Indexed: 02/07/2023]
Abstract
Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) significantly suppressed hypoxia-ischemia (HI)-induced neuroinflammation in neonatal mice. However, its underlying mechanism is still unknown. Osteopontin (OPN) is one of the key molecules involved in neuroinflammation. We demonstrate here for the first time a key role of OPN in EVs-mediated neuroinflammation following HI. Firstly, HI exposure upregulated OPN expression in Iba-1+/ TMEM119+ microglia and Iba-1+/TMEM119- monocytes/macrophages. Blocking OPN mRNA expression with LV-shOPN attenuated edema, infarct volumes, and the levels of inflammatory cytokines following HI exposure. MSCs-EVs treatment remarkably restored synaptic reorganization and up-regulated synaptic protein expression post-HI, concomitant with reducing OPN levels. Moreover, MSCs-EVs treatment rescued microglial phagocytosis of viable neurons following HI, concomitant with decreasing OPN expression. In addition, blocking NF-κB activation with pyrrolidine dithiocarbamate (PDTC, NF-κB inhibitor) or MSCs-EVs attenuated HI-induced OPN expression in the ipsilateral cortex. This study demonstrates that upregulation of OPN expression in cerebral immune cells aggravated brain damage and inflammation following HI insult. MSCs-EVs suppressed neuroinflammation, synaptic damage and microglial phagocytosis after HI injury by preventing NF-κB-mediated OPN expression in neonate mice.
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Affiliation(s)
- Danqing Xin
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44# Wenhua Xi Road, Jinan, Shandong, 250012, PR China
| | - Tingting Li
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44# Wenhua Xi Road, Jinan, Shandong, 250012, PR China
| | - Xili Chu
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44# Wenhua Xi Road, Jinan, Shandong, 250012, PR China
| | - Hongfei Ke
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44# Wenhua Xi Road, Jinan, Shandong, 250012, PR China
| | - Dexiang Liu
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, PR China
| | - Zhen Wang
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 44# Wenhua Xi Road, Jinan, Shandong, 250012, PR China.
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21
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Tajbakhsh A, Read M, Barreto GE, Ávila-Rodriguez M, Gheibi-Hayat SM, Sahebkar A. Apoptotic neurons and amyloid-beta clearance by phagocytosis in Alzheimer's disease: Pathological mechanisms and therapeutic outlooks. Eur J Pharmacol 2021; 895:173873. [PMID: 33460611 DOI: 10.1016/j.ejphar.2021.173873] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 12/13/2022]
Abstract
Neuronal survival and axonal renewal following central nervous system damage and in neurodegenerative illnesses, such as Alzheimer's disease (AD), can be enhanced by fast clearance of neuronal apoptotic debris, as well as the removal of amyloid beta (Aβ) by phagocytic cells through the process of efferocytosis. This process quickly inhibits the release of proinflammatory and antigenic autoimmune constituents, enhancing the formation of a microenvironment vital for neuronal survival and axonal regeneration. Therefore, the detrimental features associated with microglial phagocytosis uncoupling, such as the accumulation of apoptotic cells, inflammation and phagoptosis, could exacerbate the pathology in brain disease. Some mechanisms of efferocytosis could be targeted by several promising agents, such as curcumin, URMC-099 and Y-P30, which have emerged as potential treatments for AD. This review aims to investigate and update the current research regarding the signaling molecules and pathways involved in efferocytosis and how these could be targeted as a potential therapy in AD.
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Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences & Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morgayn Read
- Department of Pharmacology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland
| | | | - Seyed Mohammad Gheibi-Hayat
- Department of Medical Biotechnology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.
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22
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Lana D, Ugolini F, Giovannini MG. Space-Dependent Glia-Neuron Interplay in the Hippocampus of Transgenic Models of β-Amyloid Deposition. Int J Mol Sci 2020; 21:E9441. [PMID: 33322419 PMCID: PMC7763751 DOI: 10.3390/ijms21249441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
This review is focused on the description and discussion of the alterations of astrocytes and microglia interplay in models of Alzheimer's disease (AD). AD is an age-related neurodegenerative pathology with a slowly progressive and irreversible decline of cognitive functions. One of AD's histopathological hallmarks is the deposition of amyloid beta (Aβ) plaques in the brain. Long regarded as a non-specific, mere consequence of AD pathology, activation of microglia and astrocytes is now considered a key factor in both initiation and progression of the disease, and suppression of astrogliosis exacerbates neuropathology. Reactive astrocytes and microglia overexpress many cytokines, chemokines, and signaling molecules that activate or damage neighboring cells and their mutual interplay can result in virtuous/vicious cycles which differ in different brain regions. Heterogeneity of glia, either between or within a particular brain region, is likely to be relevant in healthy conditions and disease processes. Differential crosstalk between astrocytes and microglia in CA1 and CA3 areas of the hippocampus can be responsible for the differential sensitivity of the two areas to insults. Understanding the spatial differences and roles of glia will allow us to assess how these interactions can influence the state and progression of the disease, and will be critical for identifying therapeutic strategies.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
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23
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Lin CW, Fan CH, Chang YC, Hsieh-Li HM. ERK activation precedes Purkinje cell loss in mice with Spinocerebellar ataxia type 17. Neurosci Lett 2020; 738:135337. [PMID: 32877710 DOI: 10.1016/j.neulet.2020.135337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/27/2020] [Accepted: 08/26/2020] [Indexed: 12/18/2022]
Abstract
Spinocerebellar ataxia type 17 (SCA17) is an autosomal dominant neurodegenerative disease caused by CAG expansion in the gene encoding the TATA-binding protein (TBP). The neurological features of SCA17 are Purkinje cell loss and gliosis. We have generated SCA17 transgenic mice which recapitulate the patients' phenotypes and are suitable for the study of the SCA17 pathomechanism. Our previous study identified the activation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) occurred in the SCA17 cerebella, this study aims to study the role of ERK activation in SCA17. The levels of pERK, calbindin, and gliosis markers on the mouse cerebellum at 4-8 weeks old were analyzed to elucidate the correlation among behavioral performance, ERK activation and Purkinje cell degeneration. The motor incoordination was initiated in SCA17 mice at 6 weeks old. We found that the presence of TBP nuclear aggregation and microglia activation were observed at 4 weeks old. Gliosis of astrocytes and Bergmann glia, pERK, Bax/Bcl2 ratio, and caspase-3 were significantly increased in the 6-week-old SCA17 mouse cerebellum. In addition to the polyglutamine-protein aggregation in Purkinje cells caused apoptosis cell-autonomously, a significant body of evidence have shown that ERK pathways involves in neuronal apoptosis. Our study showed that the activation of ERK in the astrocytes and Bergmann glia was identified as preceding motor deficits, which suggest the elevated gliosis by ERK activation may contribute to neuronal apoptosis in SCA17 mice.
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Affiliation(s)
- Chia-Wei Lin
- Department of Life Science, National Taiwan Normal University, Taiwan
| | - Chia-Hao Fan
- Department of Life Science, National Taiwan Normal University, Taiwan
| | - Ya-Chin Chang
- Department of Pharmacy, Taiwan Adventist Hospital, Taiwan
| | - Hsiu Mei Hsieh-Li
- Department of Life Science, National Taiwan Normal University, Taiwan.
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24
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Scott‐Hewitt N, Perrucci F, Morini R, Erreni M, Mahoney M, Witkowska A, Carey A, Faggiani E, Schuetz LT, Mason S, Tamborini M, Bizzotto M, Passoni L, Filipello F, Jahn R, Stevens B, Matteoli M. Local externalization of phosphatidylserine mediates developmental synaptic pruning by microglia. EMBO J 2020; 39:e105380. [PMID: 32657463 PMCID: PMC7429741 DOI: 10.15252/embj.2020105380] [Citation(s) in RCA: 226] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Neuronal circuit assembly requires the fine balance between synapse formation and elimination. Microglia, through the elimination of supernumerary synapses, have an established role in this process. While the microglial receptor TREM2 and the soluble complement proteins C1q and C3 are recognized as key players, the neuronal molecular components that specify synapses to be eliminated are still undefined. Here, we show that exposed phosphatidylserine (PS) represents a neuronal "eat-me" signal involved in microglial-mediated pruning. In hippocampal neuron and microglia co-cultures, synapse elimination can be partially prevented by blocking accessibility of exposed PS using Annexin V or through microglial loss of TREM2. In vivo, PS exposure at both hippocampal and retinogeniculate synapses and engulfment of PS-labeled material by microglia occurs during established developmental periods of microglial-mediated synapse elimination. Mice deficient in C1q, which fail to properly refine retinogeniculate connections, have elevated presynaptic PS exposure and reduced PS engulfment by microglia. These data provide mechanistic insight into microglial-mediated synapse pruning and identify a novel role of developmentally regulated neuronal PS exposure that is common among developing brain structures.
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Affiliation(s)
- Nicole Scott‐Hewitt
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
- Stanley Center for Psychiatric ResearchThe Broad Institute of MIT and HarvardCambridgeMAUSA
| | - Fabio Perrucci
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
| | - Raffaella Morini
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Marco Erreni
- Unit of Advanced Optical MicroscopyHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Matthew Mahoney
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Agata Witkowska
- Laboratory of NeurobiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- Department of Molecular Pharmacology and Cell BiologyLeibniz‐Forschungsinstitut für Molekulare Pharmakologie (FMP)BerlinGermany
| | - Alanna Carey
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Elisa Faggiani
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | | | - Sydney Mason
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Matteo Tamborini
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Matteo Bizzotto
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
| | - Lorena Passoni
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Fabia Filipello
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
- Present address:
Department of NeurologyWashington UniversitySt. LouisMOUSA
| | - Reinhard Jahn
- Laboratory of NeurobiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- University of GöttingenGöttingenGermany
| | - Beth Stevens
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
- Stanley Center for Psychiatric ResearchThe Broad Institute of MIT and HarvardCambridgeMAUSA
- Howard Hughes Medical InstituteBoston Children's HospitalBostonMAUSA
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- CNR Institute of NeuroscienceMilanoItaly
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25
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Zhang Y, Li H, Li X, Wu J, Xue T, Wu J, Shen H, Li X, Shen M, Chen G. TMEM16F Aggravates Neuronal Loss by Mediating Microglial Phagocytosis of Neurons in a Rat Experimental Cerebral Ischemia and Reperfusion Model. Front Immunol 2020; 11:1144. [PMID: 32733436 PMCID: PMC7359929 DOI: 10.3389/fimmu.2020.01144] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/11/2020] [Indexed: 12/20/2022] Open
Abstract
Cerebral ischemia is a severe, acute condition, normally caused by cerebrovascular disease, and results in high rates of disability, and death. Phagoptosis is a newly recognized form of cell death caused by phagocytosis of viable cells, and has been reported to contribute to neuronal loss in brain tissue after ischemic stroke. Previous data indicated that exposure of phosphatidylserine to viable neurons could induce microglial phagocytosis of such neurons. Phosphatidylserine can be reversibly exposed to viable cells as a result of a calcium-activated phospholipid scramblase named TMEM16F. TMEM16F-mediated phospholipid scrambling on platelet membranes is critical for hemostasis and thrombosis, which plays an important role in Scott syndrome and has been confirmed by much research. However, few studies have investigated the association between TMEM16F and phagocytosis in ischemic stroke. In this study, a middle-cerebral-artery occlusion/reperfusion (MCAO/R) model was used in adult male Sprague-Dawley rats in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate cerebral ischemia-reperfusion (I/R) injury in vitro. We found that the protein level of TMEM16F was significantly increased at 12 h after I-R injury both in vivo and in vitro, and reversible phosphatidylserine exposure was confirmed in neurons undergoing I/R injury in vitro. Additionally, we constructed a LV-TMEM16F-RNAi transfection system to suppress the expression of TMEM16F during and after cerebral ischemia. As a result, TMEM16F knockdown alleviated motor function injury and decreased the microglial phagocytosis of viable neurons in the penumbra through inhibiting the “eat-me” signal phosphatidylserine. Our data indicate that reducing neuronal phosphatidylserine-exposure via deficiency of TMEM16F blocks phagocytosis of neurons and rescues stressed-but-still-viable neurons in the penumbra, which may contribute to reducing infarct volume and improving functional recovering.
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Affiliation(s)
- Yijie Zhang
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Haiying Li
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiang Li
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jie Wu
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Tao Xue
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jiang Wu
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Haitao Shen
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiang Li
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Meifen Shen
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Gang Chen
- Brain and Nerve Research Laboratory, Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
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26
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Doll JR, Hoebe K, Thompson RL, Sawtell NM. Resolution of herpes simplex virus reactivation in vivo results in neuronal destruction. PLoS Pathog 2020; 16:e1008296. [PMID: 32134994 PMCID: PMC7058292 DOI: 10.1371/journal.ppat.1008296] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 12/26/2019] [Indexed: 12/11/2022] Open
Abstract
A fundamental question in herpes simplex virus (HSV) pathogenesis is the consequence of viral reactivation to the neuron. Evidence supporting both post-reactivation survival and demise is published. The exceedingly rare nature of this event at the neuronal level in the sensory ganglion has limited direct examination of this important question. In this study, an in-depth in vivo analysis of the resolution of reactivation was undertaken. Latently infected C57BL/6 mice were induced to reactivate in vivo by hyperthermic stress. Infectious virus was detected in a high percentage (60-80%) of the trigeminal ganglia from these mice at 20 hours post-reactivation stimulus, but declined by 48 hours post-stimulus (0-13%). With increasing time post-reactivation stimulus, the percentage of reactivating neurons surrounded by a cellular cuff increased, which correlated with a decrease in detectable infectious virus and number of viral protein positive neurons. Importantly, in addition to intact viral protein positive neurons, fragmented viral protein positive neurons morphologically consistent with apoptotic bodies and containing cleaved caspase-3 were detected. The frequency of this phenotype increased through time post-reactivation. These fragmented neurons were surrounded by Iba1+ cells, consistent with phagocytic removal of dead neurons. Evidence of neuronal destruction post-reactivation prompted re-examination of the previously reported non-cytolytic role of T cells in controlling reactivation. Latently infected mice were treated with anti-CD4/CD8 antibodies prior to induced reactivation. Neither infectious virus titers nor neuronal fragmentation were altered. In contrast, when viral DNA replication was blocked during reactivation, fragmentation was not observed even though viral proteins were expressed. Our data demonstrate that at least a portion of reactivating neurons are destroyed. Although no evidence for direct T cell mediated antigen recognition in this process was apparent, inhibition of viral DNA replication blocked neuronal fragmentation. These unexpected findings raise new questions about the resolution of HSV reactivation in the host nervous system.
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Affiliation(s)
- Jessica R. Doll
- Department of Molecular Genetics, Biochemistry, and Microbiology,University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Kasper Hoebe
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Richard L. Thompson
- Department of Molecular Genetics, Biochemistry, and Microbiology,University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Nancy M. Sawtell
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
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27
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Wang H, Peng G, Wang B, Yin H, Fang X, He F, Zhao D, Liu Q, Shi L. IL-1R -/- alleviates cognitive deficits through microglial M2 polarization in AD mice. Brain Res Bull 2020; 157:10-17. [PMID: 32004659 DOI: 10.1016/j.brainresbull.2019.11.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 01/25/2023]
Abstract
The neuroinflammatory response is considered a crucial event in the pathology of Alzheimer's disease (AD). Neurotoxic amyloid β (Aβ) oligomers activate neuronal glial cells, leading to the elevated generation of a large variety of inflammatory factors. Therefore, the regulation of interleukin-1 receptor (IL-1R) activity is believed to be a potential target for AD therapy. However, previous evidence of the role of IL-1R in AD-related neuroinflammation is ambiguous. To reveal the exact role of IL-1R in AD and related inflammatory reactions, we generated IL-1R-/- AD mice. Based on the Morris water maze results, 4-month-old IL-1R-/- AD mice showed better learning and memory ability than that of AD mice. However, IL-1R-/- had little influence on amyloid precursor protein proteolysis, while IL-1R-/- increased ADAM17 expression level. Surprisingly, IL-1R-/- even enhanced glial activation. IL-1R-/- indeed attenuated inflammatory cytokine secretion, especially that of cytokins associated with M1 polarization, while it led to increased levels of some cytokins associated with M2 polarization. Finally, we found that IL-1R-/- reduced the phagocytic ability of microglia. Taken together, these results suggest that IL-1R deficiency may alleviate cognitive deficits in AD mice in a manner that is partially dependent on ADAM17 regulation and microglia M2 repolarization.
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Affiliation(s)
- Huanhuan Wang
- School of Medicine; Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China.
| | - Guoping Peng
- Department of Neurology, The 1stAffiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Bing Wang
- College of Life Science, Hangzhou Normal University, Hangzhou, China; Department of Clinical Laboratory, Northern Jiangsu People's Hospital, Yangzhou, China
| | - Hongping Yin
- School of Medicine; Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Xingyue Fang
- The 1stAffiliated Hospital, Hainan Medical School, Haikou, China
| | - Fangping He
- Department of Neurology, The 1stAffiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Dongjiu Zhao
- School of Medicine; Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Qibing Liu
- College of Science, Hainan Medical School, Haikou, China
| | - Liyun Shi
- Department of Immunology, Nanjing University of Traditional Chinese Medicine, Nanjing, China.
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28
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Role of Infiltrating Microglia/Macrophages in Glioma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:281-298. [PMID: 32034719 DOI: 10.1007/978-3-030-30651-9_14] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter we describe the state of the art knowledge of the role played by myeloid cells in promoting and supporting the growth and the invasive properties of a deadly brain tumor, glioblastoma. We provide a review of the works describing the intercellular communication among glioma and associated microglia/macrophage cells (GAMs) using in vitro cellular models derived from mice, rats and human patients and in vivo animal models using syngeneic or xenogeneic experimental systems. Special emphasis will be given to 1) the timing alteration of brain microenvironment under the influence of glioma, 2) the bidirectional communication among tumor and GAMs, 3) possible approaches to interfere with or to guide these interactions, with the aim to identify molecular and cellular targets which could revert or delay the vicious cycle that favors tumor biology.
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29
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Cannella LA, Andrews AM, Tran F, Razmpour R, McGary H, Collie C, Tsegaye T, Maynard M, Kaufman MJ, Rawls SM, Ramirez SH. Experimental Traumatic Brain Injury during Adolescence Enhances Cocaine Rewarding Efficacy and Dysregulates Dopamine and Neuroimmune Systems in Brain Reward Substrates. J Neurotrauma 2020; 37:27-42. [PMID: 31347447 PMCID: PMC6921296 DOI: 10.1089/neu.2019.6472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Although clinical studies identify traumatic brain injury (TBI) as a risk factor for the development of substance use disorder, much remains unknown about the possible underlying pathogenesis and age-specific effects. Thus, the aim of this study is to test the hypothesis that at an age of ongoing maturation, adolescent TBI alters elements of the reward pathway, resulting in increased sensitivity to the rewarding effects of a subthreshold dose of cocaine that does not induce significant behavioral changes in naïve, non-injured mice. Specifically, these results were derived from the combination of the controlled cortical impact model of TBI, performed on either adolescent (6 weeks) or young adult (8 weeks) mice, followed by the cocaine-induced conditioned place preference assay 2 weeks later. Using three-dimensional isosurface rendering and volumetric image analysis, TBI was found to induce neuromorphological changes such as decreased dendritic complexity and reduced spine density in brain regions essential for reward perception and processing of drug-induced euphoria. Further, we demonstrated that these neuronal changes may affect the differential expression of dopamine-associated genes. Our analysis also provided evidence for age-related differences in immune response and the distinct involvement of augmented microglial phagocytic activity in the remodeling of neuronal structures in the adolescent TBI brain. Our studies suggest that TBI during adolescence, a period associated with ongoing maturation of dopaminergic systems, may subsequently enhance the abuse liability of cocaine in adulthood.
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Affiliation(s)
- Lee Anne Cannella
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Allison M. Andrews
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Fionya Tran
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Roshanak Razmpour
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Hannah McGary
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Ceryce Collie
- Department of Biology, Lincoln University, Philadelphia Pennsylvania
| | - Tarik Tsegaye
- Department of Biology, Lincoln University, Philadelphia Pennsylvania
| | - Marquis Maynard
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
| | - Marc J. Kaufman
- McLean Imaging Center, McLean Hospital, Harvard Medical School, Belmont, Massachusetts
| | - Scott M. Rawls
- Center for Substance Abuse Research, Temple University, Philadelphia Pennsylvania
| | - Servio H. Ramirez
- Department of Pathology and Laboratory Medicine, Temple University, Philadelphia Pennsylvania
- Center for Substance Abuse Research, Temple University, Philadelphia Pennsylvania
- Shriners Hospital for Pediatric Research Center, Temple University, Philadelphia Pennsylvania
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30
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Allendorf DH, Puigdellívol M, Brown GC. Activated microglia desialylate their surface, stimulating complement receptor 3-mediated phagocytosis of neurons. Glia 2019; 68:989-998. [PMID: 31774586 PMCID: PMC7079032 DOI: 10.1002/glia.23757] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022]
Abstract
The glycoproteins and glycolipids of the cell surface have sugar chains that normally terminate in a sialic acid residue, but inflammatory activation of myeloid cells can cause sialidase enzymes to remove these residues, resulting in desialylation and altered activity of surface receptors, such as the phagocytic complement receptor 3 (CR3). We found that activation of microglia with lipopolysaccharide (LPS), fibrillar amyloid beta (Aβ), Tau or phorbol myristate acetate resulted in increased surface sialidase activity and desialylation of the microglial surface. Desialylation of microglia by adding sialidase, stimulated microglial phagocytosis of beads, but this was prevented by siRNA knockdown of CD11b or a blocking antibody to CD11b (a component of CR3). Desialylation of microglia by a sialyl-transferase inhibitor (3FAx-peracetyl-Neu5Ac) also stimulated microglial phagocytosis of beads. Desialylation of primary glial-neuronal co-cultures by adding sialidase or the sialyl-transferase inhibitor resulted in neuronal loss that was prevented by inhibiting phagocytosis with cytochalasin D or the blocking antibody to CD11b. Adding desialylated microglia to glial-neuronal cultures, in the absence of neuronal desialylation, also caused neuronal loss prevented by CD11b blocking antibody. Adding LPS or Aβ to primary glial-neuronal co-cultures caused neuronal loss, and this was prevented by inhibiting endogenous sialidase activity with N-acetyl-2,3-dehydro-2-deoxyneuraminic acid or blockage of CD11b. Thus, activated microglia release a sialidase activity that desialylates the cell surface, stimulating CR3-mediated phagocytosis of neurons, making extracellular sialidase and CR3 potential treatment targets to prevent inflammatory loss of neurons.
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Affiliation(s)
| | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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31
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Namekata K, Guo X, Kimura A, Arai N, Harada C, Harada T. DOCK8 is expressed in microglia, and it regulates microglial activity during neurodegeneration in murine disease models. J Biol Chem 2019; 294:13421-13433. [PMID: 31337702 DOI: 10.1074/jbc.ra119.007645] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/25/2019] [Indexed: 12/15/2022] Open
Abstract
Dedicator of cytokinesis 8 (DOCK8) is a guanine nucleotide exchange factor whose loss of function results in immunodeficiency, but its role in the central nervous system (CNS) has been unclear. Microglia are the resident immune cells of the CNS and are implicated in the pathogenesis of various neurodegenerative diseases, including multiple sclerosis (MS) and glaucoma, which affects the visual system. However, the exact roles of microglia in these diseases remain unknown. Herein, we report that DOCK8 is expressed in microglia but not in neurons or astrocytes and that its expression is increased during neuroinflammation. To define the role of DOCK8 in microglial activity, we focused on the retina, a tissue devoid of infiltrating T cells. The retina is divided into distinct layers, and in a disease model of MS/optic neuritis, DOCK8-deficient mice exhibited a clear reduction in microglial migration through these layers. Moreover, neuroinflammation severity, indicated by clinical scores, visual function, and retinal ganglion cell (RGC) death, was reduced in the DOCK8-deficient mice. Furthermore, using a glaucoma disease model, we observed impaired microglial phagocytosis of RGCs in DOCK8-deficient mice. Our data demonstrate that DOCK8 is expressed in microglia and regulates microglial activity in disease states. These findings contribute to a better understanding of the molecular pathways involved in microglial activation and implicate a role of DOCK8 in several neurological diseases.
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Affiliation(s)
- Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Nobutaka Arai
- Brain Pathology Research Center, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.
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Hermann JK, Capadona JR. Understanding the Role of Innate Immunity in the Response to Intracortical Microelectrodes. Crit Rev Biomed Eng 2019; 46:341-367. [PMID: 30806249 DOI: 10.1615/critrevbiomedeng.2018027166] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intracortical microelectrodes exhibit enormous potential for researching the nervous system, steering assistive devices and functional electrode stimulation systems for severely paralyzed individuals, and augmenting the brain with computing power. Unfortunately, intracortical microelectrodes often fail to consistently record signals over clinically useful periods. Biological mechanisms, such as the foreign body response to intracortical microelectrodes and self-perpetuating neuroinflammatory cascades, contribute to the inconsistencies and decline in recording performance. Unfortunately, few studies have directly correlated microelectrode performance with the neuroinflammatory response to the implanted devices. However, of those select studies that have, the role of the innate immune system remains among the most likely links capable of corroborating the results of different studies, across laboratories. Therefore, the overall goal of this review is to highlight the role of innate immunity signaling in the foreign body response to intracortical microelectrodes and hypothesize as to appropriate strategies that may become the most relevant in enabling brain-dwelling electrodes of any geometry, or location, for a range of clinical applications.
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Affiliation(s)
- John K Hermann
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg, Cleveland, OH 44106; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg, Cleveland, OH 44106; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702
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Rodríguez AM, Delpino MV, Miraglia MC, Giambartolomei GH. Immune Mediators of Pathology in Neurobrucellosis: From Blood to Central Nervous System. Neuroscience 2019; 410:264-273. [PMID: 31128159 DOI: 10.1016/j.neuroscience.2019.05.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 01/18/2023]
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Osorio C, Kanukuntla T, Diaz E, Jafri N, Cummings M, Sfera A. The Post-amyloid Era in Alzheimer's Disease: Trust Your Gut Feeling. Front Aging Neurosci 2019; 11:143. [PMID: 31297054 PMCID: PMC6608545 DOI: 10.3389/fnagi.2019.00143] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/29/2019] [Indexed: 12/14/2022] Open
Abstract
The amyloid hypothesis, the assumption that beta-amyloid toxicity is the primary cause of neuronal and synaptic loss, has been the mainstream research concept in Alzheimer's disease for the past two decades. Currently, this model is quietly being replaced by a more holistic, “systemic disease” paradigm which, like the aging process, affects multiple body tissues and organs, including the gut microbiota. It is well-established that inflammation is a hallmark of cellular senescence; however, the infection-senescence link has been less explored. Microbiota-induced senescence is a gradually emerging concept promoted by the discovery of pathogens and their products in Alzheimer's disease brains associated with senescent neurons, glia, and endothelial cells. Infectious agents have previously been associated with Alzheimer's disease, but the cause vs. effect issue could not be resolved. A recent study may have settled this debate as it shows that gingipain, a Porphyromonas gingivalis toxin, can be detected not only in Alzheimer's disease but also in the brains of older individuals deceased prior to developing the illness. In this review, we take the position that gut and other microbes from the body periphery reach the brain by triggering intestinal and blood-brain barrier senescence and disruption. We also surmise that novel Alzheimer's disease findings, including neuronal somatic mosaicism, iron dyshomeostasis, aggressive glial phenotypes, and loss of aerobic glycolysis, can be explained by the infection-senescence model. In addition, we discuss potential cellular senescence targets and therapeutic strategies, including iron chelators, inflammasome inhibitors, senolytic antibiotics, mitophagy inducers, and epigenetic metabolic reprograming.
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Affiliation(s)
- Carolina Osorio
- Psychiatry, Loma Linda University, Loma Linda, CA, United States
| | - Tulasi Kanukuntla
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Eddie Diaz
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Nyla Jafri
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Michael Cummings
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Adonis Sfera
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
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35
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Sui B, Cheng C, Xu P. Pyridyl Disulfide Functionalized Polymers as Nanotherapeutic Platforms. ADVANCED THERAPEUTICS 2019. [DOI: 10.1002/adtp.201900062] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Binglin Sui
- Department of Discovery and Biomedical Sciences College of Pharmacy University of South Carolina 715 Sumter Columbia SC 29208 USA
| | - Chen Cheng
- Department of Discovery and Biomedical Sciences College of Pharmacy University of South Carolina 715 Sumter Columbia SC 29208 USA
| | - Peisheng Xu
- Department of Discovery and Biomedical Sciences College of Pharmacy University of South Carolina 715 Sumter Columbia SC 29208 USA
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36
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Chew C, Kiley BJ, Sengelaub DR. Neuroprotective Effects on the Morphology of Somatic Motoneurons Following the Death of Neighboring Motoneurons: A Role for Microglia? Dev Neurobiol 2019; 79:131-154. [PMID: 30430756 DOI: 10.1002/dneu.22652] [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: 08/27/2018] [Revised: 10/19/2018] [Accepted: 10/29/2018] [Indexed: 11/08/2022]
Abstract
Partial depletion of spinal motoneuron populations induces dendritic atrophy in neighboring motoneurons, and treatment with testosterone protects motoneurons from induced dendritic atrophy. We explored a potential mechanism for this induced atrophy and protection by testosterone, examining the microglial response to partial depletion of motoneurons. Motoneurons innervating the vastus medialis muscles of adult male rats were killed by intramuscular injection of cholera toxin-conjugated saporin; some saporin-injected rats were treated with testosterone. Microglia were later visualized via immunohistochemical staining, classified as monitoring or activated, and counted stereologically. Partial motoneuron depletion increased the number of activated microglia in the quadriceps motor pool, and this increase was attenuated with testosterone treatment. The attenuation in microglial response could reflect an effect of testosterone on suppressing microglia activation, potentially sparing motoneuron dendrites. Alternatively, testosterone could be neuroprotective, sparing motoneuron dendrites, secondarily resulting in reduced microglial activation. To discriminate between these hypotheses, following partial motoneuron depletion, rats were treated with minocycline to inhibit microglial activation. Motoneurons innervating the ipsilateral vastus lateralis muscle were later labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed. Reduction of microglial activation by minocycline did not prevent induced dendritic atrophy following partial motoneuron depletion. Further, reduction of microglial activation by minocycline treatment resulted in dendritic atrophy in intact animals. Together, these findings indicate that the neuroprotective effect of testosterone on dendrites following motoneuron death is not due to inhibiting microglial activation, and that microglial activity contributes to the normal maintenance of dendritic arbors.
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Affiliation(s)
- Cory Chew
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Brandon J Kiley
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Dale R Sengelaub
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
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Tsui C, Koss K, Churchward MA, Todd KG. Biomaterials and glia: Progress on designs to modulate neuroinflammation. Acta Biomater 2019; 83:13-28. [PMID: 30414483 DOI: 10.1016/j.actbio.2018.11.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/05/2018] [Accepted: 11/06/2018] [Indexed: 02/06/2023]
Abstract
Microglia are multi-functional cells that play a vital role in establishing and maintaining the function of the nervous system and determining the fate of neurons following injury or neuropathology. The roles of microglia are diverse and essential to the capacity of the nervous system to recover from injury, however sustained inflammation can limit recovery and drive chronic disease processes such as neurodegenerative disorders. When assessing implantable therapeutic devices in the central nervous system, an improved lifetime of the implant is considered achievable through the attenuation of microglial inflammation. Consequently, there is a tremendous underexplored potential in biomaterial and engineered design to modulate neuroinflammation for therapeutic benefit. Several strategies for improving device compatibility reviewed here include: biocompatible coatings, improved designs in finer and flexible shapes to reduce tissue shear-related scarring, and loading of anti-inflammatory drugs. Studies about microglial cell cultures in 3D hydrogels and nanoscaffolds to assess various injuries and disorders are also discussed. A variety of other microglia-targeting treatments are also reviewed, including nanoparticulate systems, cellular backpacks, and gold plinths, with the intention of delivering anti-inflammatory drugs by targeting the phagocytic nature of microglia. Overall, this review highlights recent advances in biomaterials targeting microglia and inflammatory function with the potential for improving implant rejection and biocompatibility studies. STATEMENT OF SIGNIFICANCE: Microglia are the resident immune cells of the central nervous system, and thus play a central role in the neuroinflammatory response against conditions than span acute injuries, neuropsychiatric disorders, and neurodegenerative disorders. This review article presents a summary of biomaterials research that target microglia and other glial cells in order to attenuate neuroinflammation, including but not limited to: design of mechanically compliant and biocompatible stimulation electrodes, hydrogels for high-throughput 3D modelling of nervous tissue, and uptake of nanoparticle drug delivery systems. The goal of this paper is to identify strengths and gaps in the relevant literature, and to promote further consideration of microglia behaviour and neuroinflammation in biomaterial design.
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Affiliation(s)
- C Tsui
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - K Koss
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB T6G 2R3, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - M A Churchward
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB T6G 2R3, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - K G Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB T6G 2R3, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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39
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Anderson SR, Vetter ML. Developmental roles of microglia: A window into mechanisms of disease. Dev Dyn 2019; 248:98-117. [PMID: 30444278 PMCID: PMC6328295 DOI: 10.1002/dvdy.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/21/2018] [Accepted: 10/21/2018] [Indexed: 12/12/2022] Open
Abstract
Microglia are engineers of the central nervous system (CNS) both in health and disease. In addition to the canonical immunological roles of clearing damaging entities and limiting the spread of toxicity and death, microglia remodel the CNS throughout life. While they have been extensively studied in disease and injury, due to their highly variable functions, their precise role in these contexts still remains uncertain. Over the past decade, we have greatly expanded our understanding of microglial function, including their essential homeostatic roles during development. Here, we review these developmental roles, identify parallels in disease, and speculate whether developmental mechanisms re-emerge in disease and injury. Developmental Dynamics 248:98-117, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Sarah R Anderson
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah
| | - Monica L Vetter
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah
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40
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Loiola RA, Wickstead ES, Solito E, McArthur S. Estrogen Promotes Pro-resolving Microglial Behavior and Phagocytic Cell Clearance Through the Actions of Annexin A1. Front Endocrinol (Lausanne) 2019; 10:420. [PMID: 31297095 PMCID: PMC6607409 DOI: 10.3389/fendo.2019.00420] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/12/2019] [Indexed: 12/20/2022] Open
Abstract
Local production of estrogen rapidly follows brain tissue injury, but the role this hormone plays in regulating the response to neural damage or in the modulation of mediators regulating inflammation is in many ways unclear. Using the murine BV2 microglia model as well as primary microglia from wild-type and annexin A1 (AnxA1) null mice, we have identified two related mechanisms whereby estradiol can modulate microglial behavior in a receptor specific fashion. Firstly, estradiol, via estrogen receptor β (ERβ), enhanced the phagocytic clearance of apoptotic cells, acting through increased production and release of the protein AnxA1. Secondly, stimulation of either ERβ or the G protein coupled estrogen receptor GPER promoted the adoption of an anti-inflammatory/pro-resolving phenotype, an action similarly mediated through AnxA1. Together, these data suggest the hypothesis that locally produced estrogen acts through AnxA1 to exert powerful pro-resolving actions, controlling and limiting brain inflammation and ultimately protecting this highly vulnerable organ. Given the high degree of receptor selectivity in evoking these responses, we suggest that the use of selective estrogen receptor ligands may hold therapeutic promise in the treatment of neuroinflammation, avoiding unwanted generalized effects.
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Affiliation(s)
- Rodrigo Azevedo Loiola
- John Vane Science Centre, Barts and The London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
- Laboratoire de la Barrière Hémato-Encéphalique, Faculty Jean Perrin, EA 2465, Université d'Artois, Arras, France
| | - Edward S. Wickstead
- School of Life Sciences, College of Liberal Arts & Sciences, University of Westminster, London, United Kingdom
- Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Egle Solito
- John Vane Science Centre, Barts and The London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Universitá degli Studi di Napoli Federico II, Naples, Italy
| | - Simon McArthur
- Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Blizard Institute, Queen Mary University of London, London, United Kingdom
- *Correspondence: Simon McArthur
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41
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Sfera A, Gradini R, Cummings M, Diaz E, Price AI, Osorio C. Rusty Microglia: Trainers of Innate Immunity in Alzheimer's Disease. Front Neurol 2018; 9:1062. [PMID: 30564191 PMCID: PMC6288235 DOI: 10.3389/fneur.2018.01062] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/21/2018] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease, the most common form of dementia, is marked by progressive cognitive and functional impairment believed to reflect synaptic and neuronal loss. Recent preclinical data suggests that lipopolysaccharide (LPS)-activated microglia may contribute to the elimination of viable neurons and synapses by promoting a neurotoxic astrocytic phenotype, defined as A1. The innate immune cells, including microglia and astrocytes, can either facilitate or inhibit neuroinflammation in response to peripherally applied inflammatory stimuli, such as LPS. Depending on previous antigen encounters, these cells can assume activated (trained) or silenced (tolerized) phenotypes, augmenting or lowering inflammation. Iron, reactive oxygen species (ROS), and LPS, the cell wall component of gram-negative bacteria, are microglial activators, but only the latter can trigger immune tolerization. In Alzheimer's disease, tolerization may be impaired as elevated LPS levels, reported in this condition, fail to lower neuroinflammation. Iron is closely linked to immunity as it plays a key role in immune cells proliferation and maturation, but it is also indispensable to pathogens and malignancies which compete for its capture. Danger signals, including LPS, induce intracellular iron sequestration in innate immune cells to withhold it from pathogens. However, excess cytosolic iron increases the risk of inflammasomes' activation, microglial training and neuroinflammation. Moreover, it was suggested that free iron can awaken the dormant central nervous system (CNS) LPS-shedding microbes, engendering prolonged neuroinflammation that may override immune tolerization, triggering autoimmunity. In this review, we focus on iron-related innate immune pathology in Alzheimer's disease and discuss potential immunotherapeutic agents for microglial de-escalation along with possible delivery vehicles for these compounds.
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Affiliation(s)
- Adonis Sfera
- Psychiatry, Loma Linda University, Loma Linda, CA, United States.,Patton State Hospital, San Bernardino, CA, United States
| | - Roberto Gradini
- Department of Pathology, La Sapienza University of Rome, Rome, Italy
| | | | - Eddie Diaz
- Patton State Hospital, San Bernardino, CA, United States
| | - Amy I Price
- Evidence Based Medicine, University of Oxford, Oxford, United Kingdom
| | - Carolina Osorio
- Psychiatry, Loma Linda University, Loma Linda, CA, United States
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42
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Lana D, Ugolini F, Wenk GL, Giovannini MG, Zecchi-Orlandini S, Nosi D. Microglial distribution, branching, and clearance activity in aged rat hippocampus are affected by astrocyte meshwork integrity: evidence of a novel cell-cell interglial interaction. FASEB J 2018; 33:4007-4020. [PMID: 30496700 DOI: 10.1096/fj.201801539r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aging and neurodegenerative diseases share a condition of neuroinflammation entailing the production of endogenous cell debris in the CNS that must be removed by microglia ( i.e., resident macrophages), to restore tissue homeostasis. In this context, extension of microglial cell branches toward cell debris underlies the mechanisms of microglial migration and phagocytosis. Amoeboid morphology and the consequent loss of microglial branch functionality characterizes dysregulated microglia. Microglial migration is assisted by another glial population, the astroglia, which forms a dense meshwork of cytoplasmic projections. Amoeboid microglia and disrupted astrocyte meshwork are consistent traits in aged CNS. In this study, we assessed a possible correlation between microglia and astroglia morphology in rat models of chronic neuroinflammation and aging, by 3-dimensional confocal analysis implemented with particle analysis. Our findings suggest that a microglia-astroglia interaction occurs in rat hippocampus via cell-cell contacts, mediating microglial cell branching in the presence of inflammation. In aged rats, the impairment of such an interaction correlates with altered distribution, morphology, and inefficient clearance by microglia. These data support the idea that generally accepted functional boundaries between microglia and astrocytes should be re-evaluated to better understand how their functions overlap and interact.-Lana, D., Ugolini, F., Wenk, G. L., Giovannini, M. G., Zecchi-Orlandini, S., Nosi, D. Microglial distribution, branching, and clearance activity in aged rat hippocampus are affected by astrocyte meshwork integrity: evidence of a novel cell-cell interglial interaction.
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Affiliation(s)
- Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Filippo Ugolini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Gary L Wenk
- Department of Psychology, The Ohio State University, Columbus, Ohio, USA
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | | | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
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43
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Ugolini F, Lana D, Nardiello P, Nosi D, Pantano D, Casamenti F, Giovannini MG. Different Patterns of Neurodegeneration and Glia Activation in CA1 and CA3 Hippocampal Regions of TgCRND8 Mice. Front Aging Neurosci 2018; 10:372. [PMID: 30483118 PMCID: PMC6243135 DOI: 10.3389/fnagi.2018.00372] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/26/2018] [Indexed: 01/24/2023] Open
Abstract
We investigated the different patterns of neurodegeneration and glia activation in CA1 and CA3 hippocampal areas of TgCRND8 mice. The main feature of this transgenic model is the rapid development of the amyloid pathology, which starts already at 3 months of age. We performed immunohistochemical analyses to compare the different sensibility of the two hippocampal regions to neurodegeneration. We performed qualitative and quantitative evaluations by fluorescence immunohistochemistry with double or triple staining, followed by confocal microscopy and digital image analysis in stratum pyramidale (SP) and stratum radiatum (SR) of CA1 and CA3, separately. We evaluated time-dependent Aβ plaques deposition, expression of inflammatory markers, as well as quantitative and morphological alterations of neurons and glia in transgenic mice at 3 (Tg 3M) and 6 (Tg 6M) months of age, compared to WT mice. In CA1 SR of Tg 6M mice, we found significantly more Medium and Large plaques than in CA3. The pattern of neurodegeneration and astrocytes activation was different in the two areas, indicating higher sensitivity of CA1. In the CA1 SP of Tg 6M mice, we found signs of reactive astrogliosis, such as increase of astrocytes density in SP, increase of GFAP expression in SR, and elongation of astrocytes branches. We found also common patterns of glia activation and neurodegenerative processes in CA1 and CA3 of Tg 6M mice: significant increase of total and reactive microglia density in SP and SR, increased expression of TNFα, of iNOS, and IL1β in astrocytes and increased density of neurons-astrocytes-microglia triads. In CA1 SP, we found decrease of volume and number of pyramidal neurons, paralleled by increase of apoptosis, and, consequently, shrinkage of CA1 SP. These data demonstrate that in TgCRND8 mice, the responses of neurons and glia to neurodegenerative patterns induced by Aβ plaques deposition is not uniform in the two hippocampal areas, and in CA1 pyramidal neurons, the higher sensitivity may be related to the different plaque distribution in this area. All these modifications may be at the basis of memory loss, the peculiar symptom of AD, which was demonstrated in this transgenic mouse model of Aβ deposition, even at early stages.
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Affiliation(s)
- Filippo Ugolini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Pamela Nardiello
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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44
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Rustenhoven J, Smith AM, Smyth LC, Jansson D, Scotter EL, Swanson MEV, Aalderink M, Coppieters N, Narayan P, Handley R, Overall C, Park TIH, Schweder P, Heppner P, Curtis MA, Faull RLM, Dragunow M. PU.1 regulates Alzheimer's disease-associated genes in primary human microglia. Mol Neurodegener 2018; 13:44. [PMID: 30124174 PMCID: PMC6102813 DOI: 10.1186/s13024-018-0277-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 08/10/2018] [Indexed: 12/16/2022] Open
Abstract
Background Microglia play critical roles in the brain during homeostasis and pathological conditions. Understanding the molecular events underpinning microglial functions and activation states will further enable us to target these cells for the treatment of neurological disorders. The transcription factor PU.1 is critical in the development of myeloid cells and a major regulator of microglial gene expression. In the brain, PU.1 is specifically expressed in microglia and recent evidence from genome-wide association studies suggests that reductions in PU.1 contribute to a delayed onset of Alzheimer’s disease (AD), possibly through limiting neuroinflammatory responses. Methods To investigate how PU.1 contributes to immune activation in human microglia, microarray analysis was performed on primary human mixed glial cultures subjected to siRNA-mediated knockdown of PU.1. Microarray hits were confirmed by qRT-PCR and immunocytochemistry in both mixed glial cultures and isolated microglia following PU.1 knockdown. To identify attenuators of PU.1 expression in microglia, high throughput drug screening was undertaken using a compound library containing FDA-approved drugs. NanoString and immunohistochemistry was utilised to investigate the expression of PU.1 itself and PU.1-regulated mediators in primary human brain tissue derived from neurologically normal and clinically and pathologically confirmed cases of AD. Results Bioinformatic analysis of gene expression upon PU.1 silencing in mixed glial cultures revealed a network of modified AD-associated microglial genes involved in the innate and adaptive immune systems, particularly those involved in antigen presentation and phagocytosis. These gene changes were confirmed using isolated microglial cultures. Utilising high throughput screening of FDA-approved compounds in mixed glial cultures we identified the histone deacetylase inhibitor vorinostat as an effective attenuator of PU.1 expression in human microglia. Further characterisation of vorinostat in isolated microglial cultures revealed gene and protein changes partially recapitulating those seen following siRNA-mediated PU.1 knockdown. Lastly, we demonstrate that several of these PU.1-regulated genes are expressed by microglia in the human AD brain in situ. Conclusions Collectively, these results suggest that attenuating PU.1 may be a valid therapeutic approach to limit microglial-mediated inflammatory responses in AD and demonstrate utility of vorinostat for this purpose. Electronic supplementary material The online version of this article (10.1186/s13024-018-0277-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Justin Rustenhoven
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Amy M Smith
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Leon C Smyth
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Deidre Jansson
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Emma L Scotter
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Molly E V Swanson
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand
| | - Miranda Aalderink
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Natacha Coppieters
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand
| | - Pritika Narayan
- Centre for Brain Research, The University of Auckland, Auckland, New Zealand.,School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Renee Handley
- Centre for Brain Research, The University of Auckland, Auckland, New Zealand.,School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Chris Overall
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, Virginia, USA.,Departmemt of Neuroscience, University of Virginia, Charlottesville, Virginia, USA
| | - Thomas I H Park
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand.,Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand
| | | | | | - Maurice A Curtis
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. .,Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
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Gudipaty SA, Conner CM, Rosenblatt J, Montell DJ. Unconventional Ways to Live and Die: Cell Death and Survival in Development, Homeostasis, and Disease. Annu Rev Cell Dev Biol 2018; 34:311-332. [PMID: 30089222 DOI: 10.1146/annurev-cellbio-100616-060748] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Balancing cell death and survival is essential for normal development and homeostasis and for preventing diseases, especially cancer. Conventional cell death pathways include apoptosis, a form of programmed cell death controlled by a well-defined biochemical pathway, and necrosis, the lysis of acutely injured cells. New types of regulated cell death include necroptosis, pyroptosis, ferroptosis, phagoptosis, and entosis. Autophagy can promote survival or can cause death. Newly described processes of anastasis and resuscitation show that, remarkably, cells can recover from the brink of apoptosis or necroptosis. Important new work shows that epithelia achieve homeostasis by extruding excess cells, which then die by anoikis due to loss of survival signals. This mechanically regulated process both maintains barrier function as cells die and matches rates of proliferation and death. In this review, we describe these unconventional ways in which cells have evolved to die or survive, as well as the contributions that these processes make to homeostasis and cancer.
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Affiliation(s)
- Swapna A Gudipaty
- Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA
| | - Christopher M Conner
- Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA;
| | - Jody Rosenblatt
- Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA
| | - Denise J Montell
- Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA;
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Kostuk EW, Cai J, Iacovitti L. Regional microglia are transcriptionally distinct but similarly exacerbate neurodegeneration in a culture model of Parkinson's disease. J Neuroinflammation 2018; 15:139. [PMID: 29751760 PMCID: PMC5948771 DOI: 10.1186/s12974-018-1181-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/27/2018] [Indexed: 01/08/2023] Open
Abstract
Background Parkinson’s disease (PD) is characterized by selective degeneration of dopaminergic (DA) neurons of the substantia nigra pars compacta (SN) while neighboring ventral tegmental area (VTA) DA neurons are relatively spared. Mechanisms underlying the selective protection of the VTA and susceptibility of the SN are still mostly unknown. Here, we demonstrate the importance of balance between astrocytes and microglia in the susceptibility of SN DA neurons to the PD mimetic toxin 1-methyl-4-phenylpyridinium (MPP+). Methods Previously established methods were used to isolate astrocytes and microglia from the cortex (CTX), SN, and VTA, as well as embryonic midbrain DA neurons from the SN and VTA. The transcriptional profile of isolated microglia was examined for 21 canonical pro- and anti-inflammatory cytokines by qRT-PCR with and without MPP+ exposure. Homo- and heterotypic co-cultures of neurons and astrocytes were established, and the effect of altering the ratio of astrocytes and microglia in vitro on the susceptibility of midbrain DA neurons to the PD mimetic toxin MPP+ was investigated. Results We found that regionally isolated microglia (SN, VTA, CTX) exhibit basal differences in their cytokine profiles and that activation of these microglia with MPP+ results in differential cytokine upregulation. The addition of microglia to cultures of SN neurons and astrocytes was not sufficient to cause neurodegeneration; however, when challenged with MPP+, all regionally isolated microglia resulted in exacerbation of MPP+ toxicity which was alleviated by inhibition of microglial activation. Furthermore, we demonstrated that isolated VTA, but not SN, astrocytes were able to mediate protection of both SN and VTA DA neurons even in the presence of exacerbatory microglia; however, this protection could be reversed by increasing the numbers of microglia present. Conclusion These results suggest that the balance of astrocytes and microglia within the midbrain is a key factor underlying the selective vulnerability of SN DA neurons seen in PD pathogenesis and that VTA astrocytes mediate protection of DA neurons which can be countered by greater numbers of deleterious microglia. Electronic supplementary material The online version of this article (10.1186/s12974-018-1181-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eric Wildon Kostuk
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Room 320, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA, 19107, USA
| | - Jingli Cai
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Room 320, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA, 19107, USA
| | - Lorraine Iacovitti
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Room 320, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA, 19107, USA. .,Department of Neurology, Farber Institute for Neurosciences, Thomas Jefferson University, Room 320, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA, 19107, USA. .,Department of Neurosurgery, Farber Institute for Neurosciences, Thomas Jefferson University, Room 320, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA, 19107, USA.
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Rangaraju S, Raza SA, Li NX, Betarbet R, Dammer EB, Duong D, Lah JJ, Seyfried NT, Levey AI. Differential Phagocytic Properties of CD45 low Microglia and CD45 high Brain Mononuclear Phagocytes-Activation and Age-Related Effects. Front Immunol 2018; 9:405. [PMID: 29552013 PMCID: PMC5840283 DOI: 10.3389/fimmu.2018.00405] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/14/2018] [Indexed: 12/20/2022] Open
Abstract
In the central nervous system (CNS), microglia are innate immune mononuclear phagocytes (CNS MPs) that can phagocytose infectious particles, apoptotic cells, neurons, and pathological protein aggregates, such as Aβ in Alzheimer’s disease (AD). While CD11b+CD45low microglia account for the majority of CNS MPs, a small population of CD11b+CD45high CNS MPs is also recognized in AD that surround Aβ plaques. These transcriptionally and pathologically unique CD45high cells have unclear origin and undefined phagocytic characteristics. We have comprehensively validated rapid flow cytometric assays of bulk-phase and amyloid β fibril (fAβ) phagocytosis and applied these to study acutely isolated CNS MPs. Using these methods, we provide novel insights into differential abilities of CD11b+ CD45low and CD45high CNS MPs to phagocytose macroparticles and fAβ under normal, acute, and chronic neuroinflammatory states. CD45high CNS MPs also highly upregulate TREM2, CD11c, and several disease-associated microglia signature genes and have a higher phagocytic capacity for Aβ as compared to CD45low microglia in the 5xFAD mouse model of AD that becomes more apparent with aging. Our data suggest an overall pro-phagocytic and protective role for CD11b+CD45high CNS MPs in neurodegeneration, which if promoted, could be beneficial.
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Affiliation(s)
- Srikant Rangaraju
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Syed Ali Raza
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Noel Xiang'An Li
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | - Ranjita Betarbet
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Eric B Dammer
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Duc Duong
- Department of Biochemistry, Emory University, Atlanta, GA, United States
| | - James J Lah
- Department of Neurology, Emory University, Atlanta, GA, United States
| | | | - Allan I Levey
- Department of Neurology, Emory University, Atlanta, GA, United States
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Merelli A, Rodríguez JCG, Folch J, Regueiro MR, Camins A, Lazarowski A. Understanding the Role of Hypoxia Inducible Factor During Neurodegeneration for New Therapeutics Opportunities. Curr Neuropharmacol 2018; 16:1484-1498. [PMID: 29318974 PMCID: PMC6295932 DOI: 10.2174/1570159x16666180110130253] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 11/24/2017] [Accepted: 01/08/2018] [Indexed: 12/14/2022] Open
Abstract
Neurodegeneration (NDG) is linked with the progressive loss of neural function with intellectual and/or motor impairment. Several diseases affecting older individuals, including Alzheimer's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, Parkinson's disease, stroke, Multiple Sclerosis and many others, are the most relevant disorders associated with NDG. Since other pathologies such as refractory epilepsy, brain infections, or hereditary diseases such as "neurodegeneration with brain iron accumulation", also lead to chronic brain inflammation with loss of neural cells, NDG can be said to affect all ages. Owing to an energy and/or oxygen supply imbalance, different signaling mechanisms including MAPK/PI3K-Akt signaling pathways, glutamatergic synapse formation, and/or translocation of phosphatidylserine, might activate some central executing mechanism common to all these pathologies and also related to oxidative stress. Hypoxia inducible factor 1-α (HIF-1α) plays a twofold role through gene activation, in the sense that this factor has to "choose" whether to protect or to kill the affected cells. Most of the afore-mentioned processes follow a protracted course and are accompanied by progressive iron accumulation in the brain. We hypothesize that the neuroprotective effects of iron chelators are acting against the generation of free radicals derived from iron, and also induce sufficient -but not excessive- activation of HIF-1α, so that only the hypoxia-rescue genes will be activated. In this regard, the expression of the erythropoietin receptor in hypoxic/inflammatory neurons could be the cellular "sign" to act upon by the nasal administration of pharmacological doses of Neuro-EPO, inducing not only neuroprotection, but eventually, neurorepair as well.
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Affiliation(s)
| | | | | | | | | | - Alberto Lazarowski
- Address correspondence to this author at the Clinical Biochemistry Department, School of Pharmacy and Biochemistry, University of Buenos Aires-Argentina, Junín 954, Buenos Aires-Argentina; Tel: +54-11-5950-8674;, E-mail:
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Yang X, Zhang JD, Duan L, Xiong HG, Jiang YP, Liang HC. Microglia activation mediated by toll-like receptor-4 impairs brain white matter tracts in rats. J Biomed Res 2017; 32:136-144. [PMID: 29358565 PMCID: PMC5895568 DOI: 10.7555/jbr.32.20170033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Microglia activation and white matter injury coexist after repeated episodes of mild brain trauma and ischemic stroke. Axon degeneration and demyelination can activate microglia; however, it is unclear whether early microglia activation can impair the function of white matter tracts and lead to injury. Rat corpus callosum (CC) slices were treated with lipopolysaccharide (LPS) or LPS + Rhodobacter sphaeroides (RS)-LPS that is a toll-like receptor 4 (TLR-4) antagonist. Functional changes reflected by the change of axon compound action potentials (CAPs) and the accumulation of β-amyloid precursor protein (β-APP) in CC nerve fibers. Microglia activation was monitored by ionized calcium binding adaptor-1 immunofluorescent stain, based on well-established morphological criteria and paralleled proportional area measurement. Input-output (I/O) curves of CAPs in response to increased stimuli were significantly downshifted in a dose-dependent manner in LPS (0.2, 0.5 and 1.0 μg/mL)-treated slices, implying that axons neurophysiological function was undermined. LPS caused significant β-APP accumulation in CC tissues, reflecting the deterioration of fast axon transport. LPS-induced I/O curve downshift and β-APP accumulation were significantly reversed by the pre-treatment or co-incubation with RS-LPS. RS-LPS alone did not change the I/O curve. The degree of malfunction was correlated with microglia activation, as was shown by the measurements of proportional areas. Function of CC nerve fibers was evidently impaired by microglia activation and reversed by a TLP-4 antagonist, suggesting that the TLP-4 pathway lead to microglia activation.
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Affiliation(s)
- Xinglong Yang
- Department of Neurosurgery, Affiliated Hospital to Academy of Military Medicine Sciences, Beijing 100071, China
| | - Jing-Dong Zhang
- Department of Pharmacology & Experimental Neurosciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Lian Duan
- Department of Neurosurgery, Affiliated Hospital to Academy of Military Medicine Sciences, Beijing 100071, China
| | - Huan-Gui Xiong
- Department of Pharmacology & Experimental Neurosciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Yan-Ping Jiang
- Department of Otolaryngology, the 306th PLA Hospital, Beijing 100101, China
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Errant gardeners: glial-cell-dependent synaptic pruning and neurodevelopmental disorders. Nat Rev Neurosci 2017; 18:658-670. [PMID: 28931944 DOI: 10.1038/nrn.2017.110] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The final stage of brain development is associated with the generation and maturation of neuronal synapses. However, the same period is also associated with a peak in synapse elimination - a process known as synaptic pruning - that has been proposed to be crucial for the maturation of remaining synaptic connections. Recent studies have pointed to a key role for glial cells in synaptic pruning in various parts of the nervous system and have identified a set of critical signalling pathways between glia and neurons. At the same time, brain imaging and post-mortem anatomical studies suggest that insufficient or excessive synaptic pruning may underlie several neurodevelopmental disorders, including autism, schizophrenia and epilepsy. Here, we review current data on the cellular, physiological and molecular mechanisms of glial-cell-dependent synaptic pruning and outline their potential contribution to neurodevelopmental disorders.
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