1
|
Freitas GA, Niswender CM. GRM7 gene mutations and consequences for neurodevelopment. Pharmacol Biochem Behav 2023; 225:173546. [PMID: 37003303 PMCID: PMC10192299 DOI: 10.1016/j.pbb.2023.173546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The metabotropic glutamate receptor 7 (mGlu7), encoded by the GRM7 gene in humans, is a presynaptic, G protein-coupled glutamate receptor that is essential for modulating neurotransmission. Mutations in or reduced expression of GRM7 have been identified in different genetic neurodevelopmental disorders (NDDs), and rare biallelic missense variants have been proposed to underlie a subset of NDDs. Clinical GRM7 variants have been associated with a range of symptoms consistent with neurodevelopmental molecular features, including hypomyelination, brain atrophy and defects in axon outgrowth. Here, we review the newest findings regarding the cellular and molecular defects caused by GRM7 variants in NDD patients.
Collapse
Affiliation(s)
- Geanne A Freitas
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America.
| |
Collapse
|
2
|
Hoglund BK, Carfagno V, Olive MF, Leyrer-Jackson JM. Metabotropic glutamate receptors and cognition: From underlying plasticity and neuroprotection to cognitive disorders and therapeutic targets. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:367-413. [PMID: 36868635 DOI: 10.1016/bs.irn.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors that play pivotal roles in mediating the activity of neurons and other cell types within the brain, communication between cell types, synaptic plasticity, and gene expression. As such, these receptors play an important role in a number of cognitive processes. In this chapter, we discuss the role of mGlu receptors in various forms of cognition and their underlying physiology, with an emphasis on cognitive dysfunction. Specifically, we highlight evidence that links mGlu physiology to cognitive dysfunction across brain disorders including Parkinson's disease, Alzheimer's disease, Fragile X syndrome, post-traumatic stress disorder, and schizophrenia. We also provide recent evidence demonstrating that mGlu receptors may elicit neuroprotective effects in particular disease states. Lastly, we discuss how mGlu receptors can be targeted utilizing positive and negative allosteric modulators as well as subtype specific agonists and antagonist to restore cognitive function across these disorders.
Collapse
Affiliation(s)
- Brandon K Hoglund
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States
| | - Vincent Carfagno
- School of Medicine, Midwestern University, Glendale, AZ, United States
| | - M Foster Olive
- Department of Psychology, Arizona State University, Tempe, AZ, United States
| | - Jonna M Leyrer-Jackson
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States.
| |
Collapse
|
3
|
Liu T, Zhu W, Zhang X, He C, Liu X, Xin Q, Chen K, Wang H. Recent Advances in Cell and Functional Biomaterial Treatment for Spinal Cord Injury. BIOMED RESEARCH INTERNATIONAL 2022; 2022:5079153. [PMID: 35978649 PMCID: PMC9377911 DOI: 10.1155/2022/5079153] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/17/2022] [Accepted: 07/25/2022] [Indexed: 12/17/2022]
Abstract
Spinal cord injury (SCI) is a devastating central nervous system disease caused by accidental events, resulting in loss of sensory and motor function. Considering the multiple effects of primary and secondary injuries after spinal cord injury, including oxidative stress, tissue apoptosis, inflammatory response, and neuronal autophagy, it is crucial to understand the underlying pathophysiological mechanisms, local microenvironment changes, and neural tissue functional recovery for preparing novel treatment strategies. Treatment based on cell transplantation has become the forefront of spinal cord injury therapy. The transplanted cells provide physical and nutritional support for the damaged tissue. At the same time, the implantation of biomaterials with specific biological functions at the site of the SCI has also been proved to improve the local inhibitory microenvironment and promote axonal regeneration, etc. The combined transplantation of cells and functional biomaterials for SCI treatment can result in greater neuroprotective and regenerative effects by regulating cell differentiation, enhancing cell survival, and providing physical and directional support for axon regeneration and neural circuit remodeling. This article reviews the pathophysiology of the spinal cord, changes in the microenvironment after injury, and the mechanisms and strategies for spinal cord regeneration and repair. The article will focus on summarizing and discussing the latest intervention models based on cell and functional biomaterial transplantation and the latest progress in combinational therapies in SCI repair. Finally, we propose the future prospects and challenges of current treatment regimens for SCI repair, to provide references for scientists and clinicians to seek better SCI repair strategies in the future.
Collapse
Affiliation(s)
- Tianyi Liu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Wenhao Zhu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Xiaoyu Zhang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Chuan He
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Xiaolong Liu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Qiang Xin
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Kexin Chen
- Institute of Translational Medicine, First Hospital of Jilin University, Changchun 130021, China
| | - Haifeng Wang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| |
Collapse
|
4
|
Zhang Y, Chu JMT, Wong GTC. Cerebral Glutamate Regulation and Receptor Changes in Perioperative Neuroinflammation and Cognitive Dysfunction. Biomolecules 2022; 12:biom12040597. [PMID: 35454185 PMCID: PMC9029551 DOI: 10.3390/biom12040597] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 12/23/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system and is intricately linked to learning and memory. Its activity depends on the expression of AMPA and NMDA receptors and excitatory amino transporters on neurons and glial cells. Glutamate transporters prevent the excess accumulation of glutamate in synapses, which can lead to aberrant synaptic signaling, excitotoxicity, or cell death. Neuroinflammation can occur acutely after surgical trauma and contributes to the development of perioperative neurocognitive disorders, which are characterized by impairment in multiple cognitive domains. In this review, we aim to examine how glutamate handling and glutamatergic function are affected by neuroinflammation and their contribution to cognitive impairment. We will first summarize the current data regarding glutamate in neurotransmission, its receptors, and their regulation and trafficking. We will then examine the impact of inflammation on glutamate handling and neurotransmission, focusing on changes in glial cells and the effect of cytokines. Finally, we will discuss these changes in the context of perioperative neuroinflammation and the implications they have for perioperative neurocognitive disorders.
Collapse
|
5
|
Woo E, Datta D, Arnsten AFT. Glutamate Metabotropic Receptor Type 3 (mGlu3) Localization in the Rat Prelimbic Medial Prefrontal Cortex. Front Neuroanat 2022; 16:849937. [PMID: 35444520 PMCID: PMC9013768 DOI: 10.3389/fnana.2022.849937] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/18/2022] [Indexed: 11/13/2022] Open
Abstract
Metabotropic glutamate receptors type 3 (mGlu3, encoded by GRM3) are increasingly related to cognitive functioning, including the working memory operations of the prefrontal cortex (PFC). In rhesus monkeys, mGlu3 are most commonly expressed on glia (36%), but are also very prominent on layer III dendritic spines (23%) in the dorsolateral PFC (dlPFC) where they enhance working memory-related neuronal firing. In contrast, mGlu2 are predominately presynaptic in layer III of macaque dlPFC, indicating a pre- vs. post-synaptic dissociation by receptor subtype. The current study examined the cellular and subcellular localizations of mGlu3 in the rat prelimbic medial PFC (PL mPFC), a region needed for spatial working memory performance in rodents. Multiple label immunofluorescence demonstrated mGlu3 expression in neurons and astrocytes, with rare labeling in microglia. Immunoelectron microscopy of layers III and V found that the predominant location for mGlu3 was on axons (layer III: 35.9%; layer V: 44.1%), with labeling especially prominent within the intervaricose segments distant from axon terminals. mGlu3 were also found on glia (likely astrocytes), throughout the glial membrane (layer III: 28.2%; layer V: 29.5%). Importantly, mGlu3 could be seen on dendritic spines, especially in layer III (layer III: 15.6%; layer V: 8.2%), with minor labeling on dendrites. These data show that there are some similarities between mGlu3 expression in rat PL mPFC and macaque dlPFC, but the spine expression enriches and differentiates in the more recently evolved primate dlPFC.
Collapse
|
6
|
Traumatic Brain Injury: An Age-Dependent View of Post-Traumatic Neuroinflammation and Its Treatment. Pharmaceutics 2021; 13:pharmaceutics13101624. [PMID: 34683918 PMCID: PMC8537402 DOI: 10.3390/pharmaceutics13101624] [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: 08/20/2021] [Revised: 09/24/2021] [Accepted: 09/26/2021] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability all over the world. TBI leads to (1) an inflammatory response, (2) white matter injuries and (3) neurodegenerative pathologies in the long term. In humans, TBI occurs most often in children and adolescents or in the elderly, and it is well known that immune responses and the neuroregenerative capacities of the brain, among other factors, vary over a lifetime. Thus, age-at-injury can influence the consequences of TBI. Furthermore, age-at-injury also influences the pharmacological effects of drugs. However, the post-TBI inflammatory, neuronal and functional consequences have been mostly studied in experimental young adult animal models. The specificity and the mechanisms underlying the consequences of TBI and pharmacological responses are poorly understood in extreme ages. In this review, we detail the variations of these age-dependent inflammatory responses and consequences after TBI, from an experimental point of view. We investigate the evolution of microglial, astrocyte and other immune cells responses, and the consequences in terms of neuronal death and functional deficits in neonates, juvenile, adolescent and aged male animals, following a single TBI. We also describe the pharmacological responses to anti-inflammatory or neuroprotective agents, highlighting the need for an age-specific approach to the development of therapies of TBI.
Collapse
|
7
|
Mastroiacovo F, Zinni M, Mascio G, Bruno V, Battaglia G, Pansiot J, Imbriglio T, Mairesse J, Baud O, Nicoletti F. Genetic Deletion of mGlu3 Metabotropic Glutamate Receptors Amplifies Ischemic Brain Damage and Associated Neuroinflammation in Mice. Front Neurol 2021; 12:668877. [PMID: 34220677 PMCID: PMC8248796 DOI: 10.3389/fneur.2021.668877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/29/2021] [Indexed: 12/14/2022] Open
Abstract
Backgroud: Type-3 metabotropic glutamate (mGlu3) receptors are found in both neurons and glial cells and regulate synaptic transmission, astrocyte function, and microglial reactivity. Here we show that the genetic deletion of mGlu3 receptors amplifies ischemic brain damage and associated neuroinflammation in adult mice. An increased infarct size was observed in mGlu3-/- mice of both CD1 and C57Black strains 24 h following a permanent occlusion of the middle cerebral artery (MCA) as compared to their respective wild-type (mGlu3+/+ mice) counterparts. Increases in the expression of selected pro-inflammatory genes including those encoding interleukin-1β, type-2 cycloxygenase, tumor necrosis factor-α, CD86, and interleukin-6 were more prominent in the peri-infarct region of mGlu3-/- mice. In contrast, the expression of two genes associated with the anti-inflammatory phenotype of microglia (those encoding the mannose-1-phosphate receptor and the α-subunit of interleukin-4 receptor) and the gene encoding the neuroprotective factor, glial cell line-derived neurotrophic factor, was enhanced in the peri-infarct region of wild-type mice, but not mGlu3-/- mice, following MCA occlusion. In C57Black mice, the genetic deletion of mGlu3 receptors worsened the defect in the paw placement test as assessed in the contralateral forepaw at short times (4 h) following MCA occlusion. These findings suggest that mGlu3 receptors are protective against ischemic brain damage and support the way to the use of selective mGlu3 receptor agonists or positive allosteric modulators in experimental animal models of ischemic stroke.
Collapse
Affiliation(s)
| | - Manuela Zinni
- Inserm UMR1141 NeuroDiderot, University of Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Giada Mascio
- Department of Molecular Pathology, I.R.C.C.S. Neuromed, Pozzilli, Italy
| | - Valeria Bruno
- Department of Molecular Pathology, I.R.C.C.S. Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Giuseppe Battaglia
- Department of Molecular Pathology, I.R.C.C.S. Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Julien Pansiot
- Inserm UMR1141 NeuroDiderot, University of Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Tiziana Imbriglio
- Department of Molecular Pathology, I.R.C.C.S. Neuromed, Pozzilli, Italy
| | - Jerome Mairesse
- Inserm UMR1141 NeuroDiderot, University of Paris Diderot, Sorbonne Paris Cité, Paris, France.,Laboratory of Child Growth and Development, University of Geneva, Geneva, Switzerland
| | - Olivier Baud
- Inserm UMR1141 NeuroDiderot, University of Paris Diderot, Sorbonne Paris Cité, Paris, France.,Laboratory of Child Growth and Development, University of Geneva, Geneva, Switzerland.,Division of Neonatology and Pediatric Intensive Care, Children's University Hospital of Geneva, Geneva, Switzerland
| | - Ferdinando Nicoletti
- Department of Molecular Pathology, I.R.C.C.S. Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| |
Collapse
|
8
|
Fakhri S, Abbaszadeh F, Jorjani M. On the therapeutic targets and pharmacological treatments for pain relief following spinal cord injury: A mechanistic review. Biomed Pharmacother 2021; 139:111563. [PMID: 33873146 DOI: 10.1016/j.biopha.2021.111563] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal cord injury (SCI) is globally considered as one of the most debilitating disorders, which interferes with daily activities and life of the affected patients. Despite many developments in related recognizing and treating procedures, post-SCI neuropathic pain (NP) is still a clinical challenge for clinicians with no distinct treatments. Accordingly, a comprehensive search was conducted in PubMed, Medline, Scopus, Web of Science, and national database (SID and Irandoc). The relevant articles regarding signaling pathways, therapeutic targets and pharmacotherapy of post-SCI pain were also reviewed. Data were collected with no time limitation until November 2020. The present study provides the findings on molecular mechanisms and therapeutic targets, as well as developing the critical signaling pathways to introduce novel neuroprotective treatments of post-SCI pain. From the pathophysiological mechanistic point of view, post-SCI inflammation activates the innate immune system, in which the immune cells elicit secondary injuries. So, targeting the critical signaling pathways for pain management in the SCI population has significant importance in providing new treatments. Indeed, several receptors, ion channels, excitatory neurotransmitters, enzymes, and key signaling pathways could be used as therapeutic targets, with a pivotal role of n-methyl-D-aspartate, gamma-aminobutyric acid, and inflammatory mediators. The current review focuses on conventional therapies, as well as crucial signaling pathways and promising therapeutic targets for post-SCI pain to provide new insights into the clinical treatment of post-SCI pain. The need to develop innovative delivery systems to treat SCI is also considered.
Collapse
Affiliation(s)
- Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Fatemeh Abbaszadeh
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Masoumeh Jorjani
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
9
|
Qunies AM, Emmitte KA. Negative allosteric modulators of group II metabotropic glutamate receptors: A patent review (2015 - present). Expert Opin Ther Pat 2021; 31:687-708. [PMID: 33719801 DOI: 10.1080/13543776.2021.1903431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Group II metabotropic glutamate (mGlu) receptors have emerged as an attractive potential target for the development of novel CNS therapeutics in areas such as Alzheimer's disease (AD), anxiety, cognitive disorders, depression, and others. Several small molecules that act as negative allosteric modulators (NAMs) on these receptors have demonstrated efficacy and/or target engagement in animal models, and one molecule (decoglurant) has been advanced into clinical trials. AREAS COVERED This review summarizes patent applications published between January 2015 and November 2020. It is divided into three sections: (1) small molecule nonselective mGlu2/3 NAMs, (2) small molecule selective mGlu2 NAMs, and (3) small molecule selective mGlu3 NAMs. EXPERT OPINION Much progress has been made in the discovery of novel small molecule mGlu2 NAMs. Still, chemical diversity remains somewhat limited and room for expansion remains. Progress with mGlu3 NAMs has been more limited; however, some promising molecules have been disclosed. The process of elucidating the precise role of each receptor in the diseases associated with group II receptors has begun. Continued studies in animals with selective NAMs for both receptors will be critical in the coming years to inform researchers on the right compound profile and patient population for clinical development.
Collapse
Affiliation(s)
- Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA.,Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Kyle A Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| |
Collapse
|
10
|
Aryanpour R, Zibara K, Pasbakhsh P, Jame'ei SB, Namjoo Z, Ghanbari A, Mahmoudi R, Amani S, Kashani IR. 17β-Estradiol Reduces Demyelination in Cuprizone-fed Mice by Promoting M2 Microglia Polarity and Regulating NLRP3 Inflammasome. Neuroscience 2021; 463:116-127. [PMID: 33794337 DOI: 10.1016/j.neuroscience.2021.03.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/18/2021] [Accepted: 03/21/2021] [Indexed: 11/26/2022]
Abstract
Estrogen produces a beneficial role in animal models of multiple sclerosis (MS). The effect of 17β-estradiol therapy on microglia polarization and neuroinflammation in the corpus callosum of the cuprizone-induced demyelination model has not been elucidated. In this study, mice were given 0.2% cuprizone (CPZ) for 5 weeks to induce demyelination during which they received 50 ng of 17β-estradiol (EST), injected subcutaneously in the neck region, twice weekly. Data revealed that treatment with 17β-estradiol therapy (CPZ+EST) improved neurological behavioral deficits, displayed by a significant reduction in escape latencies, in comparison to untreated CPZ mice. Also, administration of 17β-estradiol caused a decrease in demyelination levels and axonal injury, as demonstrated by staining with Luxol fast blue, immunofluorescence to myelin basic protein, and transmission electron microscopy analysis. In addition, at the transcriptional level in the brain, mice treated with 17β-estradiol (CPZ+EST) showed a decrease in the levels of M1-assosicted microglia markers (CD86, iNOS and MHC-II) whereas M2-associated genes (Arg-1, CD206 and Trem-2) were increased, compared to CPZ mice. Moreover, administration of 17β-estradiol resulted in a significant reduction (∼3-fold) in transcript levels of NLRP3 inflammasome and its downstream product IL-18, compared to controls. In summary, this study demonstrated for the first time that exogenous 17β-estradiol therapy robustly leads to the reduction of M1 phenotype, stimulation of polarized M2 microglia, and repression of NLRP3 inflammasome in the corpus callosum of CPZ demyelination model of MS. The positive effects of 17β-estradiol on microglia and inflammasome seems to facilitate and accelerate the remyelination process.
Collapse
Affiliation(s)
- Roya Aryanpour
- Department of Anatomy, Faculty of Medicine, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Kazem Zibara
- PRASE and Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon.
| | - Parichehr Pasbakhsh
- Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Zeinab Namjoo
- Department of Anatomical Science, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Amir Ghanbari
- Cell and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Reza Mahmoudi
- Cell and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Showan Amani
- Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Iraj Ragerdi Kashani
- Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
11
|
Butler CA, Popescu AS, Kitchener EJA, Allendorf DH, Puigdellívol M, Brown GC. Microglial phagocytosis of neurons in neurodegeneration, and its regulation. J Neurochem 2021; 158:621-639. [PMID: 33608912 DOI: 10.1111/jnc.15327] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/13/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023]
Abstract
There is growing evidence that excessive microglial phagocytosis of neurons and synapses contributes to multiple brain pathologies. RNA-seq and genome-wide association (GWAS) studies have linked multiple phagocytic genes to neurodegenerative diseases, and knock-out of phagocytic genes has been found to protect against neurodegeneration in animal models, suggesting that excessive microglial phagocytosis contributes to neurodegeneration. Here, we review recent evidence that microglial phagocytosis of live neurons and synapses causes neurodegeneration in animal models of Alzheimer's disease and other tauopathies, Parkinson's disease, frontotemporal dementias, multiple sclerosis, retinal degeneration and neurodegeneration induced by ischaemia, infection or ageing. We also review factors regulating microglial phagocytosis of neurons, including: nucleotides, frackalkine, phosphatidylserine, calreticulin, UDP, CD47, sialylation, complement, galectin-3, Apolipoprotein E, phagocytic receptors, Siglec receptors, cytokines, microglial epigenetics and expression profile. Some of these factors may be potential treatment targets to prevent neurodegeneration mediated by excessive microglial phagocytosis of live neurons and synapses.
Collapse
Affiliation(s)
- Claire A Butler
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alma S Popescu
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| |
Collapse
|
12
|
Zinni M, Mairesse J, Pansiot J, Fazio F, Iacovelli L, Antenucci N, Orlando R, Nicoletti F, Vaiman D, Baud O. mGlu3 receptor regulates microglial cell reactivity in neonatal rats. J Neuroinflammation 2021; 18:13. [PMID: 33407565 PMCID: PMC7789385 DOI: 10.1186/s12974-020-02049-z] [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: 04/14/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Perinatal inflammation is a key factor of brain vulnerability in neonates born preterm or with intra-uterine growth restriction (IUGR), two leading conditions associated with brain injury and responsible for neurocognitive and behavioral disorders. Systemic inflammation is recognized to activate microglia, known to be the critical modulators of brain vulnerability. Although some evidence supports a role for metabotropic glutamate receptor 3 (mGlu3 receptor) in modulation of neuroinflammation, its functions are still unknown in the developing microglia. METHODS We used a double-hit rat model of perinatal brain injury induced by a gestational low-protein diet combined with interleukin-1β injections (LPD/IL-1β), mimicking both IUGR and prematurity-related inflammation. The effect of LPD/IL-1β on mGlu3 receptor expression and the effect of mGlu3 receptor modulation on microglial reactivity were investigated using a combination of pharmacological, histological, and molecular and genetic approaches. RESULTS Exposure to LPD/IL-1β significantly downregulated Grm3 gene expression in the developing microglia. Both transcriptomic analyses and pharmacological modulation of mGlu3 receptor demonstrated its central role in the control of inflammation in resting and activated microglia. Microglia reactivity to inflammatory challenge induced by LPD/IL-1β exposure was reduced by an mGlu3 receptor agonist. Conversely, both specific pharmacological blockade, siRNA knock-down, and genetic knock-out of mGlu3 receptors mimicked the pro-inflammatory phenotype observed in microglial cells exposed to LPD/IL-1β. CONCLUSIONS Overall, these data show that Grm3 plays a central role in the regulation of microglial reactivity in the immature brain. Selective pharmacological activation of mGlu3 receptors may prevent inflammatory-induced perinatal brain injury.
Collapse
Affiliation(s)
- Manuela Zinni
- Inserm UMR1141 NeuroDiderot, Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Jérôme Mairesse
- Inserm UMR1141 NeuroDiderot, Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France.,Laboratory of Child Growth and Development, University of Geneva, Geneva, Switzerland
| | - Julien Pansiot
- Inserm UMR1141 NeuroDiderot, Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France
| | | | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Nico Antenucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Daniel Vaiman
- Institut Cochin, Inserm U1016, UMR8104 CNRS, Paris, France
| | - Olivier Baud
- Inserm UMR1141 NeuroDiderot, Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France. .,Laboratory of Child Growth and Development, University of Geneva, Geneva, Switzerland. .,Division of Neonatology and Pediatric Intensive Care, Children's University Hospital of Geneva, Geneva, Switzerland.
| |
Collapse
|
13
|
Selective activation of metabotropic glutamate receptor 7 blocks paclitaxel-induced acute neuropathic pain and suppresses spinal glial reactivity in rats. Psychopharmacology (Berl) 2021; 238:107-119. [PMID: 33089875 DOI: 10.1007/s00213-020-05662-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 09/10/2020] [Indexed: 12/30/2022]
Abstract
RATIONALE Paclitaxel-induced acute pain syndrome (P-APS), characterized by deep muscle aches and arthralgia, occurs in more than 70% of patients who receive paclitaxel. P-APS can be debilitating for patients and lead to reductions and discontinuation of potentially curable therapy. Despite being relatively common in clinical practice, no clear treatment exists for P-APS and the underlying mechanisms remain poorly defined. Regulation of glutamatergic transmission by metabotropic glutamate receptors (mGluRs) has received growing attention with respect to its role in neuropathic pain. To our knowledge, no study has been conducted on alterations and functions of group III mGluR7 signaling in P-APS. OBJECTIVES In the present study, we determined whether a single administration of paclitaxel induces glutamatergic alterations and whether mGluR7 activation blocks paclitaxel-induced neuropathic pain by suppressing glial reactivity in the spinal cord. RESULTS A single paclitaxel injection dose-dependently induced acute mechanical and thermal hypersensitivity, and was associated with increased glutamate level accompanied by reduction in mGluR7 expression in the spinal cord. Selective activation of mGluR7 by its positive allosteric modulator, AMN082, blocked the development of paclitaxel-induced acute mechanical and thermal hypersensitivity, without affecting the normal pain behavior of control rats. Moreover, activation of mGluR7 by AMN082 inhibited glial reactivity and decreased pro-inflammatory cytokine release during P-APS. Abortion of spinal glial reaction to paclitaxel alleviated paclitaxel-induced acute mechanical and thermal hypersensitivity. CONCLUSIONS There results support the hypothesis that spinal mGluR7 signaling plays an important role in P-APS; Selective activation of mGluR7 by its positive allosteric modulator, AMN082, blocks P-APS in part by reducing spinal glial reactivity and neuroinflammatory process.
Collapse
|
14
|
Bukke VN, Archana M, Villani R, Romano AD, Wawrzyniak A, Balawender K, Orkisz S, Beggiato S, Serviddio G, Cassano T. The Dual Role of Glutamatergic Neurotransmission in Alzheimer's Disease: From Pathophysiology to Pharmacotherapy. Int J Mol Sci 2020; 21:ijms21207452. [PMID: 33050345 PMCID: PMC7589203 DOI: 10.3390/ijms21207452] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related dementia and neurodegenerative disorder, characterized by Aβ and tau protein deposition impairing learning, memory and suppressing synaptic plasticity of neurons. Increasing evidence suggests that there is a link between the glucose and glutamate alterations with age that down-regulates glucose utilization reducing glutamate levels in AD patients. Deviations in brain energy metabolism reinforce the development of AD by hampering glutamate levels in the brain. Glutamate is a nonessential amino acid and the major excitatory neurotransmitter synthesized from glucose. Alterations in cerebral glucose and glutamate levels precede the deposition of Aβ plaques. In the brain, over 40% of neuronal synapses are glutamatergic and disturbances in glutamatergic function have been implicated in pathophysiology of AD. Nevertheless, targeting the glutamatergic system seems to be a promising strategy to develop novel, improved therapeutics for AD. Here, we review data supporting the involvement of the glutamatergic system in AD pathophysiology as well as the efficacy of glutamatergic agents in this neurodegenerative disorder. We also discuss exciting new prospects for the development of improved therapeutics for this devastating disorder.
Collapse
Affiliation(s)
- Vidyasagar Naik Bukke
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Moola Archana
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Rosanna Villani
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Antonino Davide Romano
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Agata Wawrzyniak
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Krzysztof Balawender
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Stanislaw Orkisz
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Sarah Beggiato
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100 Chieti, Italy;
| | - Gaetano Serviddio
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
- Correspondence:
| |
Collapse
|
15
|
Spinal cord injury: pathophysiology, treatment strategies, associated challenges, and future implications. Cell Tissue Res 2019; 377:125-151. [PMID: 31065801 DOI: 10.1007/s00441-019-03039-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 04/01/2019] [Indexed: 12/16/2022]
Abstract
Axonal regeneration and formation of tripartite (axo-glial) junctions at damaged sites is a prerequisite for early repair of injured spinal cord. Transplantation of stem cells at such sites of damage which can generate both neuronal and glial population has gained impact in terms of recuperation upon infliction with spinal cord injury. In spite of the fact that a copious number of pre-clinical studies using different stem/progenitor cells have shown promising results at acute and subacute stages, at the chronic stages of injury their recovery rates have shown a drastic decline. Therefore, developing novel therapeutic strategies are the need of the hour in order to assuage secondary morbidity and effectuate improvement of the spinal cord injury (SCI)-afflicted patients' quality of life. The present review aims at providing an overview of the current treatment strategies and also gives an insight into the potential cell-based therapies for the treatment of SCI.
Collapse
|
16
|
Mazdeh M, Noroozi R, Komaki A, Azari I, Ghafouri-Fard S, Taheri M. A single nucleotide polymorphism in the metabotropic glutamate receptor 7 gene is associated with multiple sclerosis in Iranian population. Mult Scler Relat Disord 2019; 28:189-192. [DOI: 10.1016/j.msard.2019.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/29/2018] [Accepted: 01/02/2019] [Indexed: 10/27/2022]
|
17
|
Pereira V, Goudet C. Emerging Trends in Pain Modulation by Metabotropic Glutamate Receptors. Front Mol Neurosci 2019; 11:464. [PMID: 30662395 PMCID: PMC6328474 DOI: 10.3389/fnmol.2018.00464] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/30/2018] [Indexed: 12/20/2022] Open
Abstract
Pain is an essential protective mechanism meant to prevent tissue damages in organisms. On the other hand, chronic or persistent pain caused, for example, by inflammation or nerve injury is long lasting and responsible for long-term disability in patients. Therefore, chronic pain and its management represents a major public health problem. Hence, it is critical to better understand chronic pain molecular mechanisms to develop innovative and efficient drugs. Over the past decades, accumulating evidence has demonstrated a pivotal role of glutamate in pain sensation and transmission, supporting glutamate receptors as promising potential targets for pain relieving drug development. Glutamate is the most abundant excitatory neurotransmitter in the brain. Once released into the synapse, glutamate acts through ionotropic glutamate receptors (iGluRs), which are ligand-gated ion channels triggering fast excitatory neurotransmission, and metabotropic glutamate receptors (mGluRs), which are G protein-coupled receptors modulating synaptic transmission. Eight mGluRs subtypes have been identified and are divided into three classes based on their sequence similarities and their pharmacological and biochemical properties. Of note, all mGluR subtypes (except mGlu6 receptor) are expressed within the nociceptive pathways where they modulate pain transmission. This review will address the role of mGluRs in acute and persistent pain processing and emerging pharmacotherapies for pain management.
Collapse
Affiliation(s)
- Vanessa Pereira
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, France
| | - Cyril Goudet
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, France
| |
Collapse
|
18
|
Kuzmina US, Zainullina LF, Vakhitov VA, Bakhtiyarova KZ, Vakhitova YV. The role of glutamate in the pathogenesis of multiple sclerosis. Zh Nevrol Psikhiatr Im S S Korsakova 2019; 119:160-167. [DOI: 10.17116/jnevro2019119081160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
19
|
Younger D, Murugan M, Rama Rao KV, Wu LJ, Chandra N. Microglia Receptors in Animal Models of Traumatic Brain Injury. Mol Neurobiol 2018; 56:5202-5228. [DOI: 10.1007/s12035-018-1428-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
|
20
|
Spampinato SF, Copani A, Nicoletti F, Sortino MA, Caraci F. Metabotropic Glutamate Receptors in Glial Cells: A New Potential Target for Neuroprotection? Front Mol Neurosci 2018; 11:414. [PMID: 30483053 PMCID: PMC6243036 DOI: 10.3389/fnmol.2018.00414] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/25/2018] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are characterized by excitotoxicity and neuroinflammation that finally lead to slow neuronal degeneration and death. Although neurons are the principal target, glial cells are important players as they contribute by either exacerbating or dampening the events that lead to neuroinflammation and neuronal damage. A dysfunction of the glutamatergic system is a common event in the pathophysiology of these diseases. Metabotropic glutamate (mGlu) receptors belong to a large family of G protein-coupled receptors largely expressed in neurons as well as in glial cells. They often appear overexpressed in areas involved in neurodegeneration, where they can modulate glutamatergic transmission. Of note, mGlu receptor upregulation may involve microglia or, even more frequently, astrocytes, where their activation causes release of factors potentially able to influence neuronal death. The expression of mGlu receptors has been also reported on oligodendrocytes, a glial cell type specifically involved in the development of multiple sclerosis. Here we will provide a general overview on the possible involvement of mGlu receptors expressed on glial cells in the pathogenesis of different neurodegenerative disorders and the potential use of subtype-selective mGlu receptor ligands as candidate drugs for the treatment of neurodegenerative disorders. Negative allosteric modulators (NAM) of mGlu5 receptors might represent a relevant pharmacological tool to develop new neuroprotective strategies in these diseases. Recent evidence suggests that targeting astrocytes and microglia with positive allosteric modulators (PAM) of mGlu3 receptor or oligodendrocytes with mGlu4 PAMS might represent novel pharmacological approaches for the treatment of neurodegenerative disorders.
Collapse
Affiliation(s)
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy.,Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico, Pozzilli, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute, Istituto di Ricovero e Cura a Carattere Scientifico, Troina, Italy
| |
Collapse
|
21
|
Masilamoni GJ, Smith Y. Metabotropic glutamate receptors: targets for neuroprotective therapies in Parkinson disease. Curr Opin Pharmacol 2018; 38:72-80. [PMID: 29605730 DOI: 10.1016/j.coph.2018.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 03/12/2018] [Indexed: 01/22/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are heavily expressed throughout the basal ganglia (BG), where they modulate neuronal excitability, transmitter release and long term synaptic plasticity. Therefore, targeting specific mGluR subtypes by means of selective drugs could be a possible strategy for restoring normal synaptic function and neuronal activity of the BG in Parkinson disease (PD). Preclinical studies have revealed that specific mGluR subtypes mediate significant neuroprotective effects that reduce toxin-induced midbrain dopaminergic neuronal death in animal models of PD. Although the underlying mechanisms of these effects must be further studied, there is evidence that intracellular calcium regulation, anti-inflammatory effects, and glutamatergic network modulation contribute to some of these neuroprotective properties. It is noteworthy that these protective effects extend beyond midbrain dopaminergic neurons to include other monoaminergic cell groups for some mGluRs. In this review, we discuss evidence for mGluR-mediated neuroprotection in PD and highlight the challenges to translate these findings into human trials.
Collapse
Affiliation(s)
- Gunasingh J Masilamoni
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Department of Neurology, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA.
| |
Collapse
|
22
|
Fazio F, Ulivieri M, Volpi C, Gargaro M, Fallarino F. Targeting metabotropic glutamate receptors for the treatment of neuroinflammation. Curr Opin Pharmacol 2018; 38:16-23. [PMID: 29471184 DOI: 10.1016/j.coph.2018.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 01/31/2018] [Indexed: 12/15/2022]
Abstract
A large body of evidence suggests that neuroinflammation lies at the core of nearly all CNS disorders, including psychiatric disorders. Invading and local immune cells orchestrate the series of events that lead to either tissue repair or damage in response to neuroinflammation. Both lymphocytes and microglia express metabotropic glutamate (mGlu) receptors, which respond to glutamate or other endogenous activators (e.g. some kynurenine metabolites of tryptophan metabolism) influencing immune phenotype and the balance between pro-inflammatory and anti-inflammatory cytokines. Here, we offer an up-to-date on the role of individual mGlu receptor subtypes in the regulation of innate and adaptive immune response, highlighting the relevance of this information in the development of subtype-selective mGlu receptor ligands for treatment of CNS disorders.
Collapse
Affiliation(s)
| | - Martina Ulivieri
- Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Claudia Volpi
- Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, Piazzale Gambuli, 06132 Perugia, Italy
| | - Marco Gargaro
- Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, Piazzale Gambuli, 06132 Perugia, Italy
| | - Francesca Fallarino
- Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, Piazzale Gambuli, 06132 Perugia, Italy
| |
Collapse
|
23
|
Pittaluga A. CCL5-Glutamate Cross-Talk in Astrocyte-Neuron Communication in Multiple Sclerosis. Front Immunol 2017; 8:1079. [PMID: 28928746 PMCID: PMC5591427 DOI: 10.3389/fimmu.2017.01079] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022] Open
Abstract
The immune system (IS) and the central nervous system (CNS) are functionally coupled, and a large number of endogenous molecules (i.e., the chemokines for the IS and the classic neurotransmitters for the CNS) are shared in common between the two systems. These interactions are key elements for the elucidation of the pathogenesis of central inflammatory diseases. In recent years, evidence has been provided supporting the role of chemokines as modulators of central neurotransmission. It is the case of the chemokines CCL2 and CXCL12 that control pre- and/or post-synaptically the chemical transmission. This article aims to review the functional cross-talk linking another endogenous pro-inflammatory factor released by glial cells, i.e., the chemokine Regulated upon Activation Normal T-cell Expressed and Secreted (CCL5) and the principal neurotransmitter in CNS (i.e., glutamate) in physiological and pathological conditions. In particular, the review discusses preclinical data concerning the role of CCL5 as a modulator of central glutamatergic transmission in healthy and demyelinating disorders. The CCL5-mediated control of glutamate release at chemical synapses could be relevant either to the onset of psychiatric symptoms that often accompany the development of multiple sclerosis (MS), but also it might indirectly give a rationale for the progression of inflammation and demyelination. The impact of disease-modifying therapies for the cure of MS on the endogenous availability of CCL5 in CNS will be also summarized. We apologize in advance for omission in our coverage of the existing literature.
Collapse
Affiliation(s)
- Anna Pittaluga
- Department of Pharmacy, DIFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
- Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| |
Collapse
|
24
|
Amyloid-beta neurotoxicity and clearance are both regulated by glial group II metabotropic glutamate receptors. Neuropharmacology 2017; 123:274-286. [DOI: 10.1016/j.neuropharm.2017.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/05/2017] [Accepted: 05/07/2017] [Indexed: 11/20/2022]
|
25
|
Bonifacino T, Cattaneo L, Gallia E, Puliti A, Melone M, Provenzano F, Bossi S, Musante I, Usai C, Conti F, Bonanno G, Milanese M. In-vivo effects of knocking-down metabotropic glutamate receptor 5 in the SOD1 G93A mouse model of amyotrophic lateral sclerosis. Neuropharmacology 2017. [PMID: 28645622 DOI: 10.1016/j.neuropharm.2017.06.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder due to loss of upper and lower motor neurons (MNs). The mechanisms of neuronal death are largely unknown, thus prejudicing the successful pharmacological treatment. One major cause for MN degeneration in ALS is represented by glutamate(Glu)-mediated excitotoxicity. We have previously reported that activation of Group I metabotropic Glu receptors (mGluR1 and mGluR5) at glutamatergic spinal cord nerve terminals produces abnormal Glu release in the widely studied SOD1G93A mouse model of ALS. We also demonstrated that halving mGluR1 expression in the SOD1G93A mouse had a positive impact on survival, disease onset, disease progression, and on a number of cellular and biochemical readouts of ALS. We generated here SOD1G93A mice with reduced expression of mGluR5 (SOD1G93AGrm5-/+) by crossing the SOD1G93A mutant mouse with the mGluR5 heterozigous Grm5-/+ mouse. SOD1G93AGrm5-/+ mice showed prolonged survival probability and delayed pathology onset. These effects were associated to enhanced number of preserved MNs, decreased astrocyte and microglia activation, reduced cytosolic free Ca2+ concentration, and regularization of abnormal Glu release in the spinal cord of SOD1G93AGrm5-/+ mice. Unexpectedly, only male SOD1G93AGrm5-/+ mice showed improved motor skills during disease progression vs. SOD1G93A mice, while SOD1G93AGrm5-/+ females did not. These results demonstrate that a lower constitutive level of mGluR5 has a significant positive impact in mice with ALS and support the idea that blocking Group I mGluRs may represent a potentially effective pharmacological approach to the disease.
Collapse
Affiliation(s)
- Tiziana Bonifacino
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy
| | - Luca Cattaneo
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy
| | - Elena Gallia
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy
| | - Aldamaria Puliti
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy; Medical Genetics Unit, Istituto Giannina Gaslini, Via G. Gaslini, 5 - 16147, Genoa, Italy; Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 9 - 16132, Genoa, Italy
| | - Marcello Melone
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Università Politecnica delle Marche, Via Tronto 10/a - 60126, Torrette di Ancona, Ancona, Italy; Centre for Neurobiology of Aging, INRCA IRCCS, Via S.Margherita, 5 - 60124, Ancona, Italy
| | - Francesca Provenzano
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy
| | - Simone Bossi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, L.go P. Daneo, 3 - 16132, Genoa, Italy
| | - Ilaria Musante
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, L.go P. Daneo, 3 - 16132, Genoa, Italy
| | - Cesare Usai
- Institute of Biophysics, National Research Council (CNR), Via Darini, 6 - Torre di Francia, 16149, Genoa, Italy
| | - Fiorenzo Conti
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Università Politecnica delle Marche, Via Tronto 10/a - 60126, Torrette di Ancona, Ancona, Italy; Centre for Neurobiology of Aging, INRCA IRCCS, Via S.Margherita, 5 - 60124, Ancona, Italy
| | - Giambattista Bonanno
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy; Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 9 - 16132, Genoa, Italy.
| | - Marco Milanese
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa Viale Cembrano, 4 - 16148, Genoa, Italy; Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 9 - 16132, Genoa, Italy
| |
Collapse
|
26
|
The neuroprotective effects of orthosteric agonists of group II and III mGluRs in primary neuronal cell cultures are dependent on developmental stage. Neuropharmacology 2016; 111:195-211. [PMID: 27600687 DOI: 10.1016/j.neuropharm.2016.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/12/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022]
Abstract
Activation of metabotropic glutamate receptors (mGluRs) modulates neuronal excitability. Here, we evaluated the neuroprotective potential of four structurally diverse activators of group II and III mGluRs: an orthosteric agonist of group II (LY354740), an orthosteric agonist of group III (ACPT-I), an allosteric agonist of mGluR7 (AMN082) and a positive allosteric modulator (PAM) of mGluR4 (VU0361737). Neurotoxicity was induced by the pro-apoptotic agents: staurosporine (St) and doxorubicin (Dox) or the excitotoxic factor glutamate (Glu). The effects were analyzed in primary hippocampal (HIP) and cerebellar granule cell (CGC) cultures at two developmental stages, at 7 and 12 days in vitro (DIV). The data reveal a general neuroprotective effect of group II and III mGluR activators against the St- and Glu- but not Dox-induced cell damage. We found that neuroprotective effects of group II and III mGluR orthosteric agonists (LY354740 and ACPT-I) were higher at 12 DIV when compared to 7 DIV cells. In contrast, the efficiency of allosteric mGluR agents (AMN082 and VU0361737) did not differ between 7 and 12 DIV in both, St and Glu models of neuronal cell damage. Interestingly, the protective effects of activators of group II and III mGluRs were blocked by relevant antagonists only against Glu-induced neurotoxicity. Moreover, the observed neuroprotective action of group II and III mGluR activators in the St model was associated with a decreased number of PI-positive cells and no alterations in the caspase-3 activity. Finally, we showed that MAPK/ERK pathway activation was potentially involved in the mechanism of ACPT-I- and AMN082-induced neuroprotection against the St-evoked cellular damage. Our comparative study demonstrated the developmental stage-dependent neuroprotective effect of orthosteric group II and III mGluR agonists. In comparison to allosteric modulators, orthosteric compounds may provide more specific tools for suppression of neuronal cell loss associated with various chronic neurodegenerative conditions. Our results also suggest that the inhibition of intracellular pathways mediating necrotic, rather than apoptotic cascades, may be involved in neuroprotective effects of activators of group II and III mGluRs.
Collapse
|
27
|
Double Roles of Macrophages in Human Neuroimmune Diseases and Their Animal Models. Mediators Inflamm 2016; 2016:8489251. [PMID: 27034594 PMCID: PMC4808549 DOI: 10.1155/2016/8489251] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 02/21/2016] [Accepted: 02/23/2016] [Indexed: 12/22/2022] Open
Abstract
Macrophages are important immune cells of the innate immune system that are involved in organ-specific homeostasis and contribute to both pathology and resolution of diseases including infections, cancer, obesity, atherosclerosis, and autoimmune disorders. Multiple lines of evidence point to macrophages as a remarkably heterogeneous cell type. Different phenotypes of macrophages exert either proinflammatory or anti-inflammatory roles depending on the cytokines and other mediators that they are exposed to in the local microenvironment. Proinflammatory macrophages secrete detrimental molecules to induce disease development, while anti-inflammatory macrophages produce beneficial mediators to promote disease recovery. The conversion of the phenotypes of macrophages can regulate the initiation, development, and recovery of autoimmune diseases. Human neuroimmune diseases majorly include multiple sclerosis (MS), neuromyelitis optica (NMO), myasthenia gravis (MG), and Guillain-Barré syndrome (GBS) and macrophages contribute to the pathogenesis of these neuroimmune diseases. In this review, we summarize the double roles of macrophage in neuroimmune diseases and their animal models to further explore the mechanisms of macrophages involved in the pathogenesis of these disorders, which may provide a potential therapeutic approach for these disorders in the future.
Collapse
|
28
|
Di Prisco S, Merega E, Bonfiglio T, Olivero G, Cervetto C, Grilli M, Usai C, Marchi M, Pittaluga A. Presynaptic, release-regulating mGlu2 -preferring and mGlu3 -preferring autoreceptors in CNS: pharmacological profiles and functional roles in demyelinating disease. Br J Pharmacol 2016; 173:1465-77. [PMID: 26791341 DOI: 10.1111/bph.13442] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 01/08/2016] [Accepted: 01/17/2016] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE Presynaptic, release-regulating metabotropic glutamate 2 and 3 (mGlu2/3) autoreceptors exist in the CNS. They represent suitable targets for therapeutic approaches to central diseases that are typified by hyperglutamatergicity. The availability of specific ligands able to differentiate between mGlu2 and mGlu3 subunits allows us to further characterize these autoreceptors. In this study we investigated the pharmacological profile of mGlu2/3 receptors in selected CNS regions and evaluated their functions in mice with experimental autoimmune encephalomyelitis (EAE). EXPERIMENTAL APPROACH The comparative analysis of presynaptic mGlu2/3 autoreceptors was performed by determining the effect of selective mGlu2/3 receptor agonist(s) and antagonist(s) on the release of [(3)H]-D-aspartate from cortical and spinal cord synaptosomes in superfusion. In EAE mice, mGlu2/3 autoreceptor-mediated release functions were investigated and effects of in vivo LY379268 administration on impaired glutamate release examined ex vivo. KEY RESULTS Western blot analysis and confocal microscopy confirmed the presence of presynaptic mGlu2/3 receptor proteins. Cortical synaptosomes possessed LY541850-sensitive, NAAG-insensitive autoreceptors having low affinity for LY379268, while LY541850-insensitive, NAAG-sensitive autoreceptors with high affinity for LY379268 existed in spinal cord terminals. In EAE mice, mGlu2/3 autoreceptors completely lost their inhibitory activity in cortical, but not in spinal cord synaptosomes. In vivo LY379268 administration restored the glutamate exocytosis capability in spinal cord but not in cortical terminals in EAE mice. CONCLUSIONS AND IMPLICATIONS We propose the existence of mGlu2-preferring and mGlu3-preferring autoreceptors in mouse cortex and spinal cord respectively. The mGlu3 -preferring autoreceptors could represent a target for new pharmacological approaches for treating demyelinating diseases.
Collapse
Affiliation(s)
- Silvia Di Prisco
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Elisa Merega
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Tommaso Bonfiglio
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Guendalina Olivero
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Chiara Cervetto
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Massimo Grilli
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy
| | - Cesare Usai
- Institute of Biophysics, National Research Council, Genoa, Italy
| | - Mario Marchi
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy.,Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Anna Pittaluga
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy.,Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| |
Collapse
|
29
|
Xu F, Huang J, He Z, Chen J, Tang X, Song Z, Guo Q, Huang C. Microglial polarization dynamics in dorsal spinal cord in the early stages following chronic sciatic nerve damage. Neurosci Lett 2016; 617:6-13. [PMID: 26820376 DOI: 10.1016/j.neulet.2016.01.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/14/2016] [Accepted: 01/21/2016] [Indexed: 11/19/2022]
Abstract
Peripheral nerve injury can lead to activation of spinal microglia, which can mediate neuroinflammation and contribute to neuropathic pain following nerve injury. Activated microglia may manifest with either pro-inflammatory M1 phenotype or anti-inflammatory M2 phenotype, which may lead to detrimental or beneficial roles in the nervous system. In this study, microglia numbers, morphology and gene profiles were examined in the dorsal spinal cord of rats over 14 days following sciatic nerve chronic constriction injury (CCI). The morphology of some microglia changed from a surveying to an activated state within 1 day of CCI. Neuropathic pain developed within seven to 14 days following injury and microglia numbers were increased, with almost all in the dorsal spinal cord morphologically defined as activated. At day one after CCI, both M1 and M2 microglia-related genes were increased but only M1 microglia-related genes remained elevated at day seven and 14 thereafter. These results indicate that both M1 and M2 microglia were activated in the dorsal spinal cord one day after CCI but the microglia skewed towards M1 phenotype during the following seven and 14 days.
Collapse
Affiliation(s)
- Fangting Xu
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Juan Huang
- Department of Breast Surgery, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Zhenghua He
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Jia Chen
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Xiaoting Tang
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Zongbin Song
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Qulian Guo
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China
| | - Changsheng Huang
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha 410008, China.
| |
Collapse
|
30
|
Song Q, Xie D, Pan S, Xu W. Rapamycin protects neurons from brain contusion‑induced inflammatory reaction via modulation of microglial activation. Mol Med Rep 2015; 12:7203-10. [PMID: 26458361 PMCID: PMC4626160 DOI: 10.3892/mmr.2015.4407] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 02/02/2015] [Indexed: 12/17/2022] Open
Abstract
The inflammatory reaction is important in secondary injury following traumatic brain injury (TBI). Rapamycin has been demonstrated as a neuroprotective agent in a mouse model of TBI, however, there is a lack of data regarding the effects of rapamycin on the inflammatory reaction following TBI. Therefore, the present study was designed to assess the effects of treatment with rapamycin on inflammatory reactions and examine the possible involvement of microglial activation following TBI. Male imprinting control region mice were randomly divided into four groups: Sham group (n=23), TBI group (n=23), TBI + dimethyl sulfoxide (DMSO) group (n=31) and TBI + rapamycin group (n=31). Rapamycin was dissolved in DMSO (50 mg/ml) and injected 30 min after TBI (2 mg/Kg; intraperitoneally). A weight-drop model of TBI was induced, and the brain tissues were harvested 24 h after TBI. The findings indicated that the administration of rapamycin following TBI was associated with decreased levels of activated microglia and neuron degeneration at the peri-injury site, reduced levels of proinflammatory cytokines and increased neurobehavioral function, possibly mediated by inactivation of the mammalian target of rapamycin pathway. The results of the present study offer novel insight into the mechanisms responsible for the anti-neuroinflammatory effects of rapamycin, possibly involving the modulation of microglial activation.
Collapse
Affiliation(s)
- Qi Song
- Department of Healthcare, Nanjing General Hospital of Nanjing Command, Nanjing, Jiangsu 210002, P.R. China
| | - Dujiang Xie
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Shiyong Pan
- Department of Healthcare, Nanjing General Hospital of Nanjing Command, Nanjing, Jiangsu 210002, P.R. China
| | - Weijun Xu
- Department of Healthcare, Nanjing General Hospital of Nanjing Command, Nanjing, Jiangsu 210002, P.R. China
| |
Collapse
|
31
|
Jantas D, Greda A, Leskiewicz M, Grygier B, Pilc A, Lason W. Neuroprotective effects of mGluR II and III activators against staurosporine- and doxorubicin-induced cellular injury in SH-SY5Y cells: New evidence for a mechanism involving inhibition of AIF translocation. Neurochem Int 2015; 88:124-37. [PMID: 25661514 DOI: 10.1016/j.neuint.2014.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/06/2014] [Accepted: 12/28/2014] [Indexed: 12/12/2022]
Abstract
There are several experimental data sets demonstrating the neuroprotective effects of activation of group II and III metabotropic glutamate receptors (mGluR II/III), however, their effect on neuronal apoptotic processes has yet to be fully recognized. Thus, the comparison of the neuroprotective potency of the mGluR II agonist LY354740, mGluR III agonist ACPT-I, mGluR4 PAM VU0361737, mGluR8 PAM AZ12216052 and allosteric mGluR7 agonist AMN082 against staurosporine (St-) and doxorubicin (Dox)-induced cell death has been performed in undifferentiated (UN-) and retinoic acid differentiated (RA-) human neuroblastoma SH-SY5Y cells. The highest neuroprotection in UN-SH-SY5Y cells was noted for AZ12216052 (0.01-1 µM) and VU0361737 (1-10 µM), with both agents partially attenuating the St- and Dox-evoked cell death. LY354740 (0.01-10 µM) and ACPT-I (10 µM) were protective only against the St-evoked cell damage, whereas AMN082 (0.001-0.01 µM) attenuated only the Dox-induced cell death. In RA-SH-SY5Y, a moderate neuroprotective response of mGluR II/III activators was observed for LY354740 (10 µM) and AZ12216052 (0.01 and 10 µM), which afforded protection only against the St-induced cell damage. The protection mediated by mGluR II/III activators against the St- and Dox-evoked cell death in UN-SH-SY5Y cells was not related to attenuation of caspase-3 activity, however, a decrease in the number of TUNEL-positive nuclei was found. Moreover, mGluR II/III activators attenuated the cytosolic level of the apoptosis inducing factor (AIF), which was increased after St and Dox exposure. Our data point to differential neuroprotective efficacy of various mGluR II/III activators in attenuating St- and Dox-evoked cell damage in SH-SY5Y cells, and dependence of the effects on the cellular differentiation state, as well on the type of the pro-apoptotic agent that is employed. Moreover, the neuroprotection mediated by mGluR II/III activators is accompanied by inhibition of caspase-3-independent DNA fragmentation evoked by AIF translocation.
Collapse
Affiliation(s)
- D Jantas
- Department of Experimental Neuroendocrinology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland.
| | - A Greda
- Department of Experimental Neuroendocrinology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland
| | - M Leskiewicz
- Department of Experimental Neuroendocrinology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland
| | - B Grygier
- Department of Experimental Neuroendocrinology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland
| | - A Pilc
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland
| | - W Lason
- Department of Experimental Neuroendocrinology, Polish Academy of Sciences, Smetna 12 Street, Krakow PL 31-343, Poland
| |
Collapse
|
32
|
Herder V, Iskandar CD, Kegler K, Hansmann F, Elmarabet SA, Khan MA, Kalkuhl A, Deschl U, Baumgärtner W, Ulrich R, Beineke A. Dynamic Changes of Microglia/Macrophage M1 and M2 Polarization in Theiler's Murine Encephalomyelitis. Brain Pathol 2015; 25:712-23. [PMID: 25495532 DOI: 10.1111/bpa.12238] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/04/2014] [Indexed: 12/26/2022] Open
Abstract
Microglia and macrophages play a central role for demyelination in Theiler's murine encephalomyelitis (TME) virus infection, a commonly used infectious model for chronic-progressive multiple sclerosis. In order to determine the dynamic changes of microglia/macrophage polarization in TME, the spinal cord of Swiss Jim Lambert (SJL) mice was investigated by gene expression profiling and immunofluorescence. Virus persistence and demyelinating leukomyelitis were confirmed by immunohistochemistry and histology. Electron microscopy revealed continuous myelin loss together with abortive myelin repair during the late chronic infection phase indicative of incomplete remyelination. A total of 59 genes out of 151 M1- and M2-related genes were differentially expressed in TME virus-infected mice over the study period. The onset of virus-induced demyelination was associated with a dominating M1 polarization, while mounting M2 polarization of macrophages/microglia together with sustained prominent M1-related gene expression was present during the chronic-progressive phase. Molecular results were confirmed by immunofluorescence, showing an increased spinal cord accumulation of CD16/32(+) M1-, arginase-1(+) M2- and Ym1(+) M2-type cells associated with progressive demyelination. The present study provides a comprehensive database of M1-/M2-related gene expression involved in the initiation and progression of demyelination supporting the hypothesis that perpetuating interaction between virus and macrophages/microglia induces a vicious circle with persistent inflammation and impaired myelin repair in TME.
Collapse
Affiliation(s)
- Vanessa Herder
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Cut Dahlia Iskandar
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Kristel Kegler
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Florian Hansmann
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | | | - Muhammad Akram Khan
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Arno Kalkuhl
- Department of Non-Clinical Drug Safety, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach (Riss), Germany
| | - Ulrich Deschl
- Department of Non-Clinical Drug Safety, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach (Riss), Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Reiner Ulrich
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Andreas Beineke
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| |
Collapse
|
33
|
Spampinato SF, Merlo S, Chisari M, Nicoletti F, Sortino MA. Glial metabotropic glutamate receptor-4 increases maturation and survival of oligodendrocytes. Front Cell Neurosci 2015; 8:462. [PMID: 25642169 PMCID: PMC4294134 DOI: 10.3389/fncel.2014.00462] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/18/2014] [Indexed: 11/22/2022] Open
Abstract
Group III metabotropic glutamate (mGlu) receptors mediate important neuroprotective and anti-inflammatory effects. Stimulation of mGlu4 receptor reduces neuroinflammation in a mouse model of experimental autoimmune encephalomyelitis (EAE) whereas mGlu4 knockout mice display exacerbated EAE clinical scores. We now show that mGlu4 receptors are expressed in oligodendrocytes, astrocytes and microglia in culture. Oligodendrocytes express mGlu4 receptors only at early stages of maturation (O4 positive), but not when more differentiated (myelin basic protein, MBP positive). Treatment of immature oligodendrocytes with the mGlu4 receptor agonist L-2-Amino-4-phosphonobutyrate (L-AP4; 50 μM for 48 h) accelerates differentiation with enhanced branching and earlier appearance of MBP staining. Oligodendrocyte death induced by exposure to 1 mM kainic acid for 24 h is significantly reduced by a 30-min pretreatment with L-AP4 (50 μM), an effect observed only in the presence of astrocytes, mimicked by the specific mGlu4 receptor positive allosteric modulator N-Phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC) (30 μM) and prevented by pretreatment with the mGlu4 receptor antagonist, cyclopropyl-4-phosphonophenylglycine (CPPG) (100 μM). In astrocytes, mGlu4 receptor is the most expressed among group III mGlu receptors, as by Quantitative real time PCR (QRT-PCR), and its silencing prevents protective effects. Protection is also observed when conditioned medium (CM) from L-AP4-pretreated astrocytes is transferred to oligodendrocytes challenged with kainic acid. Transforming growth factor β (TGF-β) mediates the increased oligodendrocyte survival as the effect of L-AP4 is mimicked by addition of 10 ng/ml TGF-β and prevented by incubation with a neutralizing anti-TGF-β antibody. In contrast, despite the expression of mGlu4 receptor in resting and activated microglia, CM from L-AP4-stimulated microglia does not modify kainate-induced oligodendrocyte toxicity. Our results suggest that mGlu4 receptors expressed in astrocytes mediate enhanced survival of oligodendrocytes under conditions of excitotoxicity.
Collapse
Affiliation(s)
- Simona Federica Spampinato
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania Catania, Italy
| | - Sara Merlo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania Catania, Italy
| | - Mariangela Chisari
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania Catania, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University of Rome Sapienza Rome, Italy ; IRCSS Neuromed Pozzilli, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania Catania, Italy
| |
Collapse
|
34
|
n-3 PUFA supplementation benefits microglial responses to myelin pathology. Sci Rep 2014; 4:7458. [PMID: 25500548 PMCID: PMC4264015 DOI: 10.1038/srep07458] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/24/2014] [Indexed: 01/15/2023] Open
Abstract
Microglia represent rational but challenging targets for improving white matter integrity because of their dualistic protective and toxic roles. The present study examines the effect of Omega-3 polyunsaturated fatty acids (n-3 PUFAs) on microglial responses to myelin pathology in primary cultures and in the cuprizone mouse model of multiple sclerosis (MS), a devastating demyelination disease. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the two main forms of n-3 PUFAs in the brain, inhibited the release of nitric oxide and tumor necrosis factor-α from primary microglia upon IFN-γ and myelin stimulation. DHA and EPA also enhanced myelin phagocytosis in vitro. Therefore, n-3 PUFAs can inhibit inflammation while at the same time enhancing beneficial immune responses such as microglial phagocytosis. In vivo studies demonstrated that n-3 PUFA supplementation reduced cuprizone-induced demyelination and improved motor and cognitive function. The positive effects of n-3 PUFAs were accompanied by a shift in microglial polarization toward the beneficial M2 phenotype both in vitro and in vivo. These results suggest that n-3 PUFAs may be clinically useful as immunomodulatory agents for demyelinating diseases through a novel mechanism involving microglial phenotype switching.
Collapse
|
35
|
Jebelli J, Hooper C, Pocock JM. Microglial p53 activation is detrimental to neuronal synapses during activation-induced inflammation: Implications for neurodegeneration. Neurosci Lett 2014; 583:92-7. [DOI: 10.1016/j.neulet.2014.08.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 12/20/2022]
|
36
|
The role of glutamate and its receptors in multiple sclerosis. J Neural Transm (Vienna) 2014; 121:945-55. [PMID: 24633998 DOI: 10.1007/s00702-014-1188-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/27/2014] [Indexed: 12/18/2022]
Abstract
Glutamate is an excitatory neurotransmitter of the central nervous system, which has a central role in a complex communication network established between neurons, astrocytes, oligodendrocytes, and microglia. Multiple abnormal triggers such as energy deficiency, oxidative stress, mitochondrial dysfunction, and calcium overload can lead to abnormalities in glutamate signaling. Thus, the disturbance of glutamate homeostasis could affect practically all physiological functions and interactions of brain cells, leading to excitotoxicity. Excitotoxicity is the pathological process by which nerve cells are damaged or killed by excessive stimulation by glutamate. Although neuron degeneration and death are the ultimate consequences of multiple sclerosis (MS), it is now widely accepted that alterations in the function of surrounding glial cells are key features in the progression of the disease. The present knowledge raise the possibility that the modulation of glutamate release and transport, as well as receptors blockade or glutamate metabolism modulation, might be relevant targets for the development of future therapeutic interventions in MS.
Collapse
|
37
|
Stirling DP, Cummins K, Mishra M, Teo W, Yong VW, Stys P. Toll-like receptor 2-mediated alternative activation of microglia is protective after spinal cord injury. Brain 2013; 137:707-23. [DOI: 10.1093/brain/awt341] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
|
38
|
Williams CJ, Dexter DT. Neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease. J Neurochem 2013; 129:4-20. [PMID: 24224472 DOI: 10.1111/jnc.12608] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 10/28/2013] [Accepted: 11/06/2013] [Indexed: 12/21/2022]
Abstract
Neurodegenerative disorders possess common pathological mechanisms, such as protein aggregation, inflammation, oxidative stress (OS) and excitotoxicity, raising the possibility of shared therapeutic targets. As a result of the selective cellular and regional expression of group III metabotropic glutamate (mGlu) receptors, drugs targeting such receptors have demonstrated both neuroprotective properties and symptomatic improvements in several models of neurodegeneration. In recent years, the discovery and development of subtype-selective ligands for the group III mGlu receptors has gained pace, allowing further research into the functions of these receptors and revealing their roles in health and disease. Activation of this class of receptors results in neuroprotection, with a variety of underlying mechanisms implicated. Group III mGlu receptor stimulation prevents excitotoxicity by inhibiting glutamate release from neurons and microglia and increasing glutamate uptake by astrocytes. It also attenuates the neuroinflammatory response by reducing glial reactivity and encourages neurotrophic phenotypes. This article will review the current literature with regard to the neuroprotective and symptomatic effects of group III mGlu receptor activation and discuss their promise as therapeutic targets in neurodegenerative disease. We review the neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease: Excess extracellular glutamate causes overactivation of NMDA receptors resulting in excitotoxicity. Externalization of phosphatidylserine stimulates phagocytosis of neurons by activated microglia, which contribute to damage through glutamate and pro-inflammatory factor release. Reactive astrocytes produce cytotoxic factors enhancing neuronal cell death. Activation of group III mGlu receptors by glutamate and/or mGlu receptor ligands results in inhibition of glutamate release from presynaptic terminals and microglia, reducing excitotoxicity. Astrocytic glutamate uptake is increased and microglia produce neurotrophic factors.
Collapse
Affiliation(s)
- Claire J Williams
- Parkinson's Disease Research Group, Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | |
Collapse
|
39
|
Domercq M, Vázquez-Villoldo N, Matute C. Neurotransmitter signaling in the pathophysiology of microglia. Front Cell Neurosci 2013; 7:49. [PMID: 23626522 PMCID: PMC3630369 DOI: 10.3389/fncel.2013.00049] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/05/2013] [Indexed: 01/09/2023] Open
Abstract
Microglial cells are the resident immune cells of the central nervous system. In the resting state, microglia are highly dynamic and control the environment by rapidly extending and retracting motile processes. Microglia are closely associated with astrocytes and neurons, particularly at the synapses, and more recent data indicate that neurotransmission plays a role in regulating the morphology and function of surveying/resting microglia, as they are endowed with receptors for most known neurotransmitters. In particular, microglia express receptors for ATP and glutamate, which regulate microglial motility. After local damage, the release of ATP induces microgliosis and activated microglial cells migrate to the site of injury, proliferate, and phagocytose cells, and cellular compartments. However, excessive activation of microglia could contribute to the progression of chronic neurodegenerative diseases, though the underlying mechanisms are still unclear. Microglia have the capacity to release a large number of substances that can be detrimental to the surrounding neurons, including glutamate, ATP, and reactive oxygen species. However, how altered neurotransmission following acute insults or chronic neurodegenerative conditions modulates microglial functions is still poorly understood. This review summarizes the relevant data regarding the role of neurotransmitter receptors in microglial physiology and pathology.
Collapse
Affiliation(s)
- María Domercq
- Departamento de Neurociencias, Universidad del País Vasco-UPV/EHU Leioa, Spain ; Achucarro Basque Center for Neuroscience-UPV/EHU Zamudio, Spain ; Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas Leioa, Spain
| | | | | |
Collapse
|
40
|
Blockage of CR1 prevents activation of rodent microglia. Neurobiol Dis 2013; 54:139-49. [PMID: 23454195 DOI: 10.1016/j.nbd.2013.02.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 01/31/2013] [Accepted: 02/19/2013] [Indexed: 12/22/2022] Open
Abstract
The importance of the complement system in Alzheimer's disease (AD) pathogenesis has been emphasized through recent genome wide association studies. However, the cellular and molecular role of these complement proteins is not fully understood. Microglia express complement receptors and the activation of specific receptors may increase Aβ clearance and reduce neurodegeneration. Here, we investigated the contribution of complement receptor 1 (CR1), the second most significant hit in GWAS studies, on microglia to neuronal damage. We show that microglia displaying an activated phenotype demonstrate an increase in CR1 expression. We also provide evidence that activation of microglial CR1 was detrimental to neurons and this correlated with an increase in microglial intracellular superoxide generation, and tumour necrosis factor-α (TNFα) and interleukin-1 β (IL-1β) secretion. Amyloid-β 42 (Aβ1-42)-treated microglia displayed an increased ability to phagocytose dextran beads following antibody blockage of CR1 but a decreased capacity to phagocytose fluorescent-tagged Aβ1-42. Together, these results indicate that microglial CR1 plays a role in the neuronal death observed in AD and investigating this further may provide a possible strategy to control neurotoxicity in the AD brain.
Collapse
|
41
|
Abstract
Pro-inflammatory stimuli evoke an export of glutamate from microglia that is sufficient to contribute to excitotoxicity in neighbouring neurons. Since microglia also express various glutamate receptors themselves, we were interested in the potential feedback of glutamate on this system. Several agonists of mGluRs (metabotropic glutamate receptors) were applied to primary rat microglia, and the export of glutamate into their culture medium was evoked by LPS (lipopolysaccharide). Agonists of group-II and -III mGluR ACPD [(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid] and L-AP4 [L-(+)-2-amino-4-phosphonobutyric acid] were both capable of completely blocking the glutamate export without interfering with the production of NO (nitric oxide); the group-I agonist tADA (trans-azetidine-2,4-dicarboxylic acid) was ineffective. Consistent with the possibility of feedback, inhibition of mGluR by MSPG [(R,S)-α-2-methyl-4sulfonophenylglycine] potentiated glutamate export. As the group-II and -III mGluR are coupled to Gαi-containing G-proteins and the inhibition of adenylate cyclase, we explored the role of cAMP in this effect. Inhibition of cAMP-dependent protein kinase [also known as protein kinase A (PKA)] by H89 mimicked the effect of ACPD, and the mGluR agonist had its actions reversed by artificially sustaining cAMP through the PDE (phosphodiesterase) inhibitor IBMX (isobutylmethylxanthine) or the cAMP mimetic dbcAMP (dibutyryl cAMP). These data indicate that mGluR activation attenuates a potentially neurotoxic export of glutamate from activated microglia and implicate cAMP as a contributor to this aspect of microglial action.
Collapse
|
42
|
Targeting metabotropic glutamate receptors in neuroimmune communication. Neuropharmacology 2012; 63:501-6. [PMID: 22640632 DOI: 10.1016/j.neuropharm.2012.05.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/15/2012] [Accepted: 05/17/2012] [Indexed: 01/13/2023]
Abstract
L-Glutamate (L-Glu) is the principal excitatory neurotransmitter in the Central Nervous System (CNS), where it regulates cellular and synaptic activity, neuronal plasticity, cell survival and other relevant functions. Glutamatergic neurotransmission is complex and involves both ionotropic (ligand-gated ion channels; iGluRs) and metabotropic receptors (G-protein coupled receptors). Recent evidence suggests that glutamatergic receptors are also expressed by immune cells, regulating the degree of cell activation. In this review we primarily focus on mGluRs and their role in the crosstalk between the central nervous and immune systems during neuroinflammation.
Collapse
|
43
|
Mead EL, Mosley A, Eaton S, Dobson L, Heales SJ, Pocock JM. Microglial neurotransmitter receptors trigger superoxide production in microglia; consequences for microglial-neuronal interactions. J Neurochem 2012; 121:287-301. [DOI: 10.1111/j.1471-4159.2012.07659.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
44
|
Berger J, Dumont A, Focant M, Vergouts M, Sternotte A, Calas AG, Goursaud S, Hermans E. Opposite regulation of metabotropic glutamate receptor 3 and metabotropic glutamate receptor 5 by inflammatory stimuli in cultured microglia and astrocytes. Neuroscience 2012; 205:29-38. [DOI: 10.1016/j.neuroscience.2011.12.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 12/13/2011] [Accepted: 12/23/2011] [Indexed: 01/09/2023]
|
45
|
Loane DJ, Stoica BA, Faden AI. Metabotropic glutamate receptor-mediated signaling in neuroglia. ACTA ACUST UNITED AC 2012; 1:136-150. [PMID: 22662309 DOI: 10.1002/wmts.30] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are G-protein-coupled receptors, which include eight subtypes that have been classified into three groups (I-III) based upon sequence homology, signal transduction mechanism and pharmacological profile. Although most studied with regard to neuronal function and modulation, mGlu receptors are also expressed by neuroglia-including astrocytes, microglia and oligodendrocytes. Activation of mGlu receptors on neuroglia under both physiologic and pathophysiologic conditions mediates numerous actions that are essential for intrinsic glial cell function, as well as for glial-neuronal interactions. Astrocyte mGlu receptors play important physiological roles in regulating neurotransmission and maintaining neuronal homeostasis. However, mGlu receptors on astrocytes and microglia also serve to modulate cell death and neurological function in a variety of pathophysiological conditions such as acute and chronic neurodegenerative disorders. The latter effects are complex and bi-directional, depending on which mGlu receptor sub-types are activated.
Collapse
Affiliation(s)
- David J Loane
- Department of Anesthesiology & Center for Shock, Trauma and Anesthesiology Research (STAR), National Study Center for Trauma and EMS, University of Maryland School of Medicine, Baltimore, MD
| | | | | |
Collapse
|
46
|
Positive allosteric modulation of metabotropic glutamate receptor 5 down-regulates fibrinogen-activated microglia providing neuronal protection. Neurosci Lett 2011; 505:140-5. [PMID: 22015768 DOI: 10.1016/j.neulet.2011.10.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 09/30/2011] [Accepted: 10/03/2011] [Indexed: 12/19/2022]
Abstract
Microglial activation and blood brain barrier dysfunction are significant hallmarks in an array of neurodegenerative disorders. A leaky blood brain barrier potentially allows infiltration of blood-borne proteins into the CNS parenchyma, and previous studies have shown that the blood borne protein fibrinogen (FG) can activate microglia to produce a neurotoxic phenotype. Here we show that FG-mediated neurotoxicity and ERK1/2 phosphorylation in neuronal cultures is significantly attenuated by activation of metabotropic glutamate receptor 5 (mGluR5) but not mGluR2. Furthermore, FG-mediated microglial activation was down-regulated by direct mGluR5 activation on these cells but not by mGluR2, suggesting that targeting microglial mGluR5 provides neuronal protection against blood protein-triggered innate inflammatory responses.
Collapse
|
47
|
Loane DJ, Byrnes KR. Role of microglia in neurotrauma. Neurotherapeutics 2010; 7:366-77. [PMID: 20880501 PMCID: PMC2948548 DOI: 10.1016/j.nurt.2010.07.002] [Citation(s) in RCA: 465] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 05/26/2010] [Accepted: 07/01/2010] [Indexed: 01/12/2023] Open
Abstract
Microglia are the primary mediators of the immune defense system of the CNS and are integral to the subsequent inflammatory response. The role of microglia in the injured CNS is under scrutiny, as research has begun to fully explore how postinjury inflammation contributes to secondary damage and recovery of function. Whether microglia are good or bad is under debate, with strong support for a dual role or differential activation of microglia. Microglia release a number of factors that modulate secondary injury and recovery after injury, including pro- and anti-inflammatory cytokines, chemokines, nitric oxide, prostaglandins, growth factors, and superoxide species. Here we review experimental work on the complex and varied responses of microglia in terms of both detrimental and beneficial effects. Addressed in addition are the effects of microglial activation in two examples of CNS injury: spinal cord and traumatic brain injury. Microglial activation is integral to the response of CNS tissue to injury. In that light, future research is needed to focus on clarifying the signals and mechanisms by which microglia can be guided to promote optimal functional recovery.
Collapse
Affiliation(s)
- David J. Loane
- Department of Anesthesiology & Center for Shock, Trauma and Anesthesiology Research (STAR), National Study Center for Trauma and EMS, University of Maryland School of Medicine, 21201 Baltimore, Maryland
| | - Kimberly R. Byrnes
- grid.265436.00000000104215525Room B2048, Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, 20814 Bethesda, MD
| |
Collapse
|
48
|
Abstract
Microglial activation is an early response to brain ischemia and many other stressors. Microglia continuously monitor and respond to changes in brain homeostasis and to specific signaling molecules expressed or released by neighboring cells. These signaling molecules, including ATP, glutamate, cytokines, prostaglandins, zinc, reactive oxygen species, and HSP60, may induce microglial proliferation and migration to the sites of injury. They also induce a nonspecific innate immune response that may exacerbate acute ischemic injury. This innate immune response includes release of reactive oxygen species, cytokines, and proteases. Microglial activation requires hours to days to fully develop, and thus presents a target for therapeutic intervention with a much longer window of opportunity than acute neuroprotection. Effective agents are now available for blocking both microglial receptor activation and the microglia effector responses that drive the inflammatory response after stroke. Effective agents are also available for targeting the signal transduction mechanisms linking these events. However, the innate immune response can have beneficial as well deleterious effects on outcome after stoke, and a challenge will be to find ways to selectively suppress the deleterious effects of microglial activation after stroke without compromising neurovascular repair and remodeling.
Collapse
Affiliation(s)
- Midori A. Yenari
- Department of Neurology, University of California San Francisco and San Francisco Veterans Affairs Medical Center, 94121 San Francisco, California
| | - Tiina M. Kauppinen
- Department of Neurology, University of California San Francisco and San Francisco Veterans Affairs Medical Center, 94121 San Francisco, California
| | - Raymond A. Swanson
- Department of Neurology, University of California San Francisco and San Francisco Veterans Affairs Medical Center, 94121 San Francisco, California
| |
Collapse
|
49
|
Abstract
Microglia are resident CNS immune cells that are active sensors in healthy brain and versatile effectors under pathological conditions. Cerebral ischemia induces a robust neuroinflammatory response that includes marked changes in the gene-expression profile and phenotype of a variety of endogenous CNS cell types (astrocytes, neurons and microglia), as well as an influx of leukocytic cells (neutrophils, macrophages and T-cells) from the periphery. Many molecules and conditions can trigger a transformation of surveying microglia to microglia of an alerted or reactive state. Here we review recent developments in the literature that relate to microglial activation in the experimental setting of in vitro and in vivo ischemia. We also present new data from our own laboratory demonstrating the direct effects of in vitro ischemic conditions on the microglial phenotype and genomic profile. In particular, we focus on the role of specific molecular signaling systems, such as hypoxia inducible factor-1 and Toll-like receptor-4, in regulating the microglial response in this setting. We then review histological and novel radiological data that confirm a key role for microglial activation in the setting of ischemic stroke in humans. We also discuss recent progress in the pharmacologic and molecular targeting of microglia in acute ischemic stroke. Finally, we explore how recent studies on ischemic preconditioning have increased interest in pre-emptively targeting microglial activation in order to reduce stroke severity.
Collapse
Affiliation(s)
- Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington 98195-6465, USA Tel.: +1 206 221 5362
| | | | | |
Collapse
|
50
|
von Bernhardi R, Tichauer JE, Eugenín J. Aging-dependent changes of microglial cells and their relevance for neurodegenerative disorders. J Neurochem 2009; 112:1099-114. [PMID: 20002526 DOI: 10.1111/j.1471-4159.2009.06537.x] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Among multiple structural and functional brain changes, aging is accompanied by an increase of inflammatory signaling in the nervous system as well as a dysfunction of the immune system elsewhere. Although the long-held view that aging involves neurocognitive impairment is now dismissed, aging is a major risk factor for neurodegenerative diseases such as Alzheimer;s disease, Parkinson;s disease and Huntington's disease, among others. There are many age-related changes affecting the brain, contributing both to certain declining in function and increased frailty, which could singly and collectively affect neuronal viability and vulnerability. Among those changes, both inflammatory responses in aged brains and the altered regulation of toll like receptors, which appears to be relevant for understanding susceptibility to neurodegenerative processes, are linked to pathogenic mechanisms of several diseases. Here, we review how aging and pro-inflammatory environment could modulate microglial phenotype and its reactivity and contribute to the genesis of neurodegenerative processes. Data support our idea that age-related microglial cell changes, by inducing cytotoxicity in contrast to neuroprotection, could contribute to the onset of neurodegenerative changes. This view can have important implications for the development of new therapeutic approaches.
Collapse
Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Marcoleta, Santiago, Chile.
| | | | | |
Collapse
|