1
|
Fernández-Gómez B, Marchena MA, Piñeiro D, Gómez-Martín P, Sánchez E, Laó Y, Valencia G, Nocera S, Benítez-Fernández R, Castaño-León AM, Lagares A, Hernández-Jiménez M, de Castro F. ApTOLL: A new therapeutic aptamer for cytoprotection and (re)myelination after multiple sclerosis. Br J Pharmacol 2024; 181:3263-3281. [PMID: 38742374 DOI: 10.1111/bph.16399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 11/17/2023] [Accepted: 12/11/2023] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND AND PURPOSE ApTOLL is an aptamer selected to antagonize toll-like receptor 4 (TLR4), a relevant actor for innate immunity involved in inflammatory responses in multiple sclerosis (MS) and other diseases. The currently available therapeutic arsenal to treat MS is composed of immunomodulators but, to date, there are no (re)myelinating drugs available in clinics. In our present study, we studied the effect of ApTOLL on different animal models of MS. EXPERIMENTAL APPROACH The experimental autoimmune encephalomyelitis (EAE) model was used to evaluate the effect of ApTOLL on reducing the inflammatory component. A more direct effect on oligodendroglia was studied with the cuprizone model and purified primary cultures of murine and human oligodendrocyte precursor cells (OPCs) isolated through magnetic-activated cell sorting (MACS) from samples of brain cortex. Also, we tested these effects in an ex vivo model of organotypic cultures demyelinated with lysolecithin (LPC). KEY RESULTS ApTOLL treatment positively impacted the clinical symptomatology of mice in the EAE and cuprizone models, which was associated with better preservation plus restoration of myelin and oligodendrocytes in the demyelinated lesions of animals. Restoration was corroborated on purified cultures of rodent and human OPCs. CONCLUSION AND IMPLICATIONS Our findings reveal a new therapeutic approach for the treatment of inflammatory and demyelinating diseases such as MS. The molecular nature of the aptamer exerts not only an anti-inflammatory effect but also neuroprotective and remyelinating effects. The excellent safety profile demonstrated by ApTOLL in animals and humans opens the door to future clinical trials in MS patients.
Collapse
Affiliation(s)
- Beatriz Fernández-Gómez
- Instituto Cajal-CSIC, Madrid, Spain
- AptaTargets SL, Madrid, Spain
- PhD Program in Neuroscience, Universidad Autónoma de Madrid-Cajal Institute, Madrid, Spain
| | - Miguel A Marchena
- Instituto Cajal-CSIC, Madrid, Spain
- Facultad HM de Ciencias de la Salud de la Universidad Camilo José Cela
- Instituto de Investigación Sanitaria HM Hospitales
| | | | | | | | | | | | | | | | | | - Alfonso Lagares
- Servicio de Neurocirugía, Hospital 12 de Octubre, Madrid, Spain
| | - Macarena Hernández-Jiménez
- AptaTargets SL, Madrid, Spain
- Unidad de Investigación Neurovascular, Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | | |
Collapse
|
2
|
Helbing DL, Haas F, Cirri E, Rahnis N, Dau TTD, Kelmer Sacramento E, Oraha N, Böhm L, Lajqi T, Fehringer P, Morrison H, Bauer R. Impact of inflammatory preconditioning on murine microglial proteome response induced by focal ischemic brain injury. Front Immunol 2024; 15:1227355. [PMID: 38655254 PMCID: PMC11036884 DOI: 10.3389/fimmu.2024.1227355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 03/11/2024] [Indexed: 04/26/2024] Open
Abstract
Preconditioning with lipopolysaccharide (LPS) induces neuroprotection against subsequent cerebral ischemic injury, mainly involving innate immune pathways. Microglia are resident immune cells of the central nervous system (CNS) that respond early to danger signals through memory-like differential reprogramming. However, the cell-specific molecular mechanisms underlying preconditioning are not fully understood. To elucidate the distinct molecular mechanisms of preconditioning on microglia, we compared these cell-specific proteomic profiles in response to LPS preconditioning and without preconditioning and subsequent transient focal brain ischemia and reperfusion, - using an established mouse model of transient focal brain ischemia and reperfusion. A proteomic workflow, based on isolated microglia obtained from mouse brains by cell sorting and coupled to mass spectrometry for identification and quantification, was applied. Our data confirm that LPS preconditioning induces marked neuroprotection, as indicated by a significant reduction in brain infarct volume. The established brain cell separation method was suitable for obtaining an enriched microglial cell fraction for valid proteomic analysis. The results show a significant impact of LPS preconditioning on microglial proteome patterns by type I interferons, presumably driven by the interferon cluster regulator proteins signal transducer and activator of transcription1/2 (STAT1/2).
Collapse
Affiliation(s)
- Dario Lucas Helbing
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, Jena, Germany
- German Center for Mental Health (DZPG), Site Halle-Jena-Magdeburg, Jena, Germany
| | - Fabienne Haas
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Emilio Cirri
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Norman Rahnis
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | | | | | - Nova Oraha
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Leopold Böhm
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
- Department of Microbiology and Hospital Hygiene, Bundeswehr Central Hospital Koblenz, Koblenz, Germany
| | - Trim Lajqi
- Department of Neonatology, Heidelberg University Children’s Hospital, Heidelberg, Germany
| | - Pascal Fehringer
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Helen Morrison
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
- Faculty of Biological Sciences, Friedrich-Schiller University, Jena, Germany
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| |
Collapse
|
3
|
Ni J, Xie Z, Quan Z, Meng J, Qing H. How brain 'cleaners' fail: Mechanisms and therapeutic value of microglial phagocytosis in Alzheimer's disease. Glia 2024; 72:227-244. [PMID: 37650384 DOI: 10.1002/glia.24465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/10/2023] [Accepted: 08/19/2023] [Indexed: 09/01/2023]
Abstract
Microglia are the resident phagocytes of the brain, where they primarily function in the clearance of dead cells and the removal of un- or misfolded proteins. The impaired activity of receptors or proteins involved in phagocytosis can result in enhanced inflammation and neurodegeneration. RNA-seq and genome-wide association studies have linked multiple phagocytosis-related genes to neurodegenerative diseases, while the knockout of such genes has been demonstrated to exert protective effects against neurodegeneration in animal models. The failure of microglial phagocytosis influences AD-linked pathologies, including amyloid β accumulation, tau propagation, neuroinflammation, and infection. However, a precise understanding of microglia-mediated phagocytosis in Alzheimer's disease (AD) is still lacking. In this review, we summarize current knowledge of the molecular mechanisms involved in microglial phagocytosis in AD across a wide range of pre-clinical, post-mortem, ex vivo, and clinical studies and review the current limitations regarding the detection of microglia phagocytosis in AD. Finally, we discuss the rationale of targeting microglial phagocytosis as a therapeutic strategy for preventing AD or slowing its progression.
Collapse
Affiliation(s)
- Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhen Xie
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhenzhen Quan
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jie Meng
- Department of Geriatrics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| |
Collapse
|
4
|
Zhu Z, Zhang L, Elsherbini A, Crivelli SM, Tripathi P, Harper C, Quadri Z, Spassieva SD, Bieberich E. The S1P receptor 1 antagonist Ponesimod reduces TLR4-induced neuroinflammation and increases Aβ clearance in 5XFAD mice. EBioMedicine 2023; 94:104713. [PMID: 37480622 PMCID: PMC10393615 DOI: 10.1016/j.ebiom.2023.104713] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/24/2023] Open
Abstract
BACKGROUND Previously, we showed that the sphingosine-1-phosphate (S1P) transporter spinster 2 (Spns2) mediates activation of microglia in response to amyloid β peptide (Aβ). Here, we investigated if Ponesimod, a functional S1P receptor 1 (S1PR1) antagonist, prevents Aβ-induced activation of glial cells and Alzheimer's disease (AD) pathology. METHODS We used primary cultures of glial cells and the 5XFAD mouse model to determine the effect of Aβ and Ponesimod on glial activation, Aβ phagocytosis, cytokine levels and pro-inflammatory signaling pathways, AD pathology, and cognitive performance. FINDINGS Aβ42 increased the levels of TLR4 and S1PR1, leading to their complex formation. Ponesimod prevented the increase in TLR4 and S1PR1 levels, as well as the formation of their complex. It also reduced the activation of the pro-inflammatory Stat1 and p38 MAPK signaling pathways, while activating the anti-inflammatory Stat6 pathway. This was consistent with increased phagocytosis of Aβ42 in primary cultured microglia. In 5XFAD mice, Ponesimod decreased the levels of TNF-α and CXCL10, which activate TLR4 and Stat1. It also increased the level of IL-33, an anti-inflammatory cytokine that promotes Aβ42 phagocytosis by microglia. As a result of these changes, Ponesimod decreased the number of Iba-1+ microglia and GFAP+ astrocytes, and the size and number of amyloid plaques, while improving spatial memory as measured in a Y-maze test. INTERPRETATION Ponesimod targeting S1PR1 is a promising therapeutic approach to reprogram microglia, reduce neuroinflammation, and increase Aβ clearance in AD. FUNDING NIHR01AG064234, RF1AG078338, R21AG078601, VAI01BX003643.
Collapse
Affiliation(s)
- Zhihui Zhu
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Liping Zhang
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Ahmed Elsherbini
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Simone M Crivelli
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Priyanka Tripathi
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Carmen Harper
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Zainuddin Quadri
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Stefka D Spassieva
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States; Veterans Affairs Medical Center, Lexington, KY 40502, United States.
| |
Collapse
|
5
|
Miao J, Ma H, Yang Y, Liao Y, Lin C, Zheng J, Yu M, Lan J. Microglia in Alzheimer's disease: pathogenesis, mechanisms, and therapeutic potentials. Front Aging Neurosci 2023; 15:1201982. [PMID: 37396657 PMCID: PMC10309009 DOI: 10.3389/fnagi.2023.1201982] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by protein aggregation in the brain. Recent studies have revealed the critical role of microglia in AD pathogenesis. This review provides a comprehensive summary of the current understanding of microglial involvement in AD, focusing on genetic determinants, phenotypic state, phagocytic capacity, neuroinflammatory response, and impact on synaptic plasticity and neuronal regulation. Furthermore, recent developments in drug discovery targeting microglia in AD are reviewed, highlighting potential avenues for therapeutic intervention. This review emphasizes the essential role of microglia in AD and provides insights into potential treatments.
Collapse
Affiliation(s)
- Jifei Miao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Haixia Ma
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yang Yang
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yuanpin Liao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Cui Lin
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Juanxia Zheng
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Muli Yu
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Jiao Lan
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| |
Collapse
|
6
|
Marshall KL, Rajbhandari L, Venkatesan A, Maragakis NJ, Farah MH. Enhanced axonal regeneration of ALS patient iPSC-derived motor neurons harboring SOD1 A4V mutation. Sci Rep 2023; 13:5597. [PMID: 37020097 PMCID: PMC10076424 DOI: 10.1038/s41598-023-31720-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/16/2023] [Indexed: 04/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, characterized by degeneration of upper and lower motor neurons that leads to muscle weakness, paralysis, and death, but the effects of disease-causing mutations on axonal outgrowth of neurons derived from human induced pluripotent stem cells (iPSC)-derived motor neurons (hiPSC-MN) are poorly understood. The use of hiPSC-MN is a promising tool to develop more relevant models for target identification and drug development in ALS research, but questions remain concerning the effects of distinct disease-causing mutations on axon regeneration. Mutations in superoxide dismutase 1 (SOD1) were the first to be discovered in ALS patients. Here, we investigated the effect of the SOD1A4V mutation on axonal regeneration of hiPSC-MNs, utilizing compartmentalized microfluidic devices, which are powerful tools for studying hiPSC-MN distal axons. Surprisingly, SOD1+/A4V hiPSC-MNs regenerated axons more quickly following axotomy than those expressing the native form of SOD1. Though initial axon regrowth was not significantly different following axotomy, enhanced regeneration was apparent at later time points, indicating an increased rate of outgrowth. This regeneration model could be used to identify factors that enhance the rate of human axon regeneration.
Collapse
Affiliation(s)
- Katherine L Marshall
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Labchan Rajbhandari
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Arun Venkatesan
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Nicholas J Maragakis
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Mohamed H Farah
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.
| |
Collapse
|
7
|
The Pathological Activation of Microglia Is Modulated by Sexually Dimorphic Pathways. Int J Mol Sci 2023; 24:ijms24054739. [PMID: 36902168 PMCID: PMC10003784 DOI: 10.3390/ijms24054739] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/11/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Microglia are the primary immunocompetent cells of the central nervous system (CNS). Their ability to survey, assess and respond to perturbations in their local environment is critical in their role of maintaining CNS homeostasis in health and disease. Microglia also have the capability of functioning in a heterogeneous manner depending on the nature of their local cues, as they can become activated on a spectrum from pro-inflammatory neurotoxic responses to anti-inflammatory protective responses. This review seeks to define the developmental and environmental cues that support microglial polarization towards these phenotypes, as well as discuss sexually dimorphic factors that can influence this process. Further, we describe a variety of CNS disorders including autoimmune disease, infection, and cancer that demonstrate disparities in disease severity or diagnosis rates between males and females, and posit that microglial sexual dimorphism underlies these differences. Understanding the mechanism behind differential CNS disease outcomes between men and women is crucial in the development of more effective targeted therapies.
Collapse
|
8
|
Yu F, Wang Y, Stetler AR, Leak RK, Hu X, Chen J. Phagocytic microglia and macrophages in brain injury and repair. CNS Neurosci Ther 2022; 28:1279-1293. [PMID: 35751629 PMCID: PMC9344092 DOI: 10.1111/cns.13899] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/31/2022] [Accepted: 06/04/2022] [Indexed: 12/21/2022] Open
Abstract
AIMS Phagocytosis is the cellular digestion of extracellular particles, such as pathogens and dying cells, and is a key element in the evolution of central nervous system (CNS) disorders. Microglia and macrophages are the professional phagocytes of the CNS. By clearing toxic cellular debris and reshaping the extracellular matrix, microglia/macrophages help pilot the brain repair and functional recovery process. However, CNS resident and invading immune cells can also magnify tissue damage by igniting runaway inflammation and phagocytosing stressed-but viable-neurons. DISCUSSION Microglia/macrophages help mediate intercellular communication and react quickly to the "find-me" signals expressed by dead/dying neurons. The activated microglia/macrophages then migrate to the injury site to initiate the phagocytic process upon encountering "eat-me" signals on the surfaces of endangered cells. Thus, healthy cells attempt to avoid inappropriate engulfment by expressing "do not-eat-me" signals. Microglia/macrophages also have the capacity to phagocytose immune cells that invade the injured brain (e.g., neutrophils) and to regulate their pro-inflammatory properties. During brain recovery, microglia/macrophages engulf myelin debris, initiate synaptogenesis and neurogenesis, and sculpt a favorable extracellular matrix to support network rewiring, among other favorable roles. Here, we review the multilayered nature of phagocytotic microglia/macrophages, including the molecular and cellular mechanisms that govern microglia/macrophage-induced phagocytosis in acute brain injury, and discuss strategies that tap into the therapeutic potential of this engulfment process. CONCLUSION Identification of biological targets that can temper neuroinflammation after brain injury without hindering the essential phagocytic functions of microglia/macrophages will expedite better medical management of the stroke recovery stage.
Collapse
Affiliation(s)
- Fang Yu
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Yangfan Wang
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Anne R. Stetler
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Rehana K. Leak
- Graduate School of Pharmaceutical SciencesSchool of Pharmacy, Duquesne UniversityPittsburghPennsylvaniaUSA
| | - Xiaoming Hu
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jun Chen
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| |
Collapse
|
9
|
Lima MN, Barbosa-Silva MC, Maron-Gutierrez T. Microglial Priming in Infections and Its Risk to Neurodegenerative Diseases. Front Cell Neurosci 2022; 16:878987. [PMID: 35783096 PMCID: PMC9240317 DOI: 10.3389/fncel.2022.878987] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/26/2022] [Indexed: 11/29/2022] Open
Abstract
Infectious diseases of different etiologies have been associated with acute and long-term neurological consequences. The primary cause of these consequences appears to be an inflammatory process characterized primarily by a pro-inflammatory microglial state. Microglial cells, the local effectors' cells of innate immunity, once faced by a stimulus, alter their morphology, and become a primary source of inflammatory cytokines that increase the inflammatory process of the brain. This inflammatory scenario exerts a critical role in the pathogenesis of neurodegenerative diseases. In recent years, several studies have shown the involvement of the microglial inflammatory response caused by infections in the development of neurodegenerative diseases. This has been associated with a transitory microglial state subsequent to an inflammatory response, known as microglial priming, in which these cells are more responsive to stimuli. Thus, systemic inflammation and infections induce a transitory state in microglia that may lead to changes in their state and function, making priming them for subsequent immune challenges. However, considering that microglia are long-lived cells and are repeatedly exposed to infections during a lifetime, microglial priming may not be beneficial. In this review, we discuss the relationship between infections and neurodegenerative diseases and how this may rely on microglial priming.
Collapse
Affiliation(s)
- Maiara N. Lima
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Maria C. Barbosa-Silva
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Tatiana Maron-Gutierrez
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation, Rio de Janeiro, Brazil
| |
Collapse
|
10
|
Amirifar L, Shamloo A, Nasiri R, de Barros NR, Wang ZZ, Unluturk BD, Libanori A, Ievglevskyi O, Diltemiz SE, Sances S, Balasingham I, Seidlits SK, Ashammakhi N. Brain-on-a-chip: Recent advances in design and techniques for microfluidic models of the brain in health and disease. Biomaterials 2022; 285:121531. [DOI: 10.1016/j.biomaterials.2022.121531] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 04/10/2022] [Accepted: 04/15/2022] [Indexed: 12/12/2022]
|
11
|
Konishi H, Koizumi S, Kiyama H. Phagocytic astrocytes: Emerging from the shadows of microglia. Glia 2022; 70:1009-1026. [PMID: 35142399 PMCID: PMC9305589 DOI: 10.1002/glia.24145] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/18/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the maintenance of a healthy CNS or for recovery after injury. Live cells or parts thereof, such as the synapses and myelin, are appropriately eliminated by phagocytosis to maintain or refine neural networks during development and adulthood. Microglia, the specific population of resident macrophages in the CNS, are classically considered as primary phagocytes; however, astrocytes have also been highlighted as phagocytes in the last decade. Phagocytic targets and receptors are reported to be mostly common between astrocytes and microglia, which raises the question of how astrocytic phagocytosis differs from microglial phagocytosis, and how these two phagocytic systems cooperate. In this review, we address the consequences of astrocytic phagocytosis, particularly focusing on these elusive points.
Collapse
Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
12
|
Li H, Liu S, Han J, Li S, Gao X, Wang M, Zhu J, Jin T. Role of Toll-Like Receptors in Neuroimmune Diseases: Therapeutic Targets and Problems. Front Immunol 2021; 12:777606. [PMID: 34790205 PMCID: PMC8591135 DOI: 10.3389/fimmu.2021.777606] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/15/2021] [Indexed: 12/16/2022] Open
Abstract
Toll-like receptors (TLRs) are a class of proteins playing a key role in innate and adaptive immune responses. TLRs are involved in the development and progression of neuroimmune diseases via initiating inflammatory responses. Thus, targeting TLRs signaling pathway may be considered as a potential therapy for neuroimmune diseases. However, the role of TLRs is elusive and complex in neuroimmune diseases. In addition to the inadequate immune response of TLRs inhibitors in the experiments, the recent studies also demonstrated that partial activation of TLRs is conducive to the production of anti-inflammatory factors and nervous system repair. Exploring the mechanism of TLRs in neuroimmune diseases and combining with developing the emerging drug may conquer neuroimmune diseases in the future. Herein, we provide an overview of the role of TLRs in several neuroimmune diseases, including multiple sclerosis, neuromyelitis optica spectrum disorder, Guillain-Barré syndrome and myasthenia gravis. Emerging difficulties and potential solutions in clinical application of TLRs inhibitors will also be discussed.
Collapse
Affiliation(s)
- Haixia Li
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Shan Liu
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jinming Han
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Shengxian Li
- Department of Urology, The First Hospital of Jilin University, Changchun, China
| | - Xiaoyan Gao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Meng Wang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jie Zhu
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Karolinska University Hospital, Solna, Sweden
| | - Tao Jin
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| |
Collapse
|
13
|
Microglia as the Critical Regulators of Neuroprotection and Functional Recovery in Cerebral Ischemia. Cell Mol Neurobiol 2021; 42:2505-2525. [PMID: 34460037 DOI: 10.1007/s10571-021-01145-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022]
Abstract
Microglial activation is considered as the critical pathogenic event in diverse central nervous system disorders including cerebral ischemia. Proinflammatory responses of activated microglia have been well reported in the ischemic brain and neuroinflammatory responses of activated microglia have been believed to be the potential therapeutic strategy. However, despite having proinflammatory roles, microglia can have significant anti-inflammatory roles and they are associated with the production of growth factors which are responsible for neuroprotection and recovery after ischemic injury. Microglia can directly promote neuroprotection by preventing ischemic infarct expansion and promoting functional outcomes. Indirectly, microglia are involved in promoting anti-inflammatory responses, neurogenesis, and angiogenesis in the ischemic brain which are crucial pathophysiological events for ischemic recovery. In fact, anti-inflammatory cytokines and growth factors produced by microglia can promote neuroprotection and attenuate neurobehavioral deficits. In addition, microglia regulate phagocytosis, axonal regeneration, blood-brain barrier protection, white matter integrity, and synaptic remodeling, which are essential for ischemic recovery. Microglia can also regulate crosstalk with neurons and other cell types to promote neuroprotection and ischemic recovery. This review mainly focuses on the roles of microglia in neuroprotection and recovery following ischemic injury. Furthermore, this review also sheds the light on the therapeutic potential of microglia in stroke patients.
Collapse
|
14
|
Aldskogius H, Kozlova EN. Dorsal Root Injury-A Model for Exploring Pathophysiology and Therapeutic Strategies in Spinal Cord Injury. Cells 2021; 10:2185. [PMID: 34571835 PMCID: PMC8470715 DOI: 10.3390/cells10092185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the cellular and molecular mechanisms of spinal cord injury is fundamental for our possibility to develop successful therapeutic approaches. These approaches need to address the issues of the emergence of a non-permissive environment for axonal growth in the spinal cord, in combination with a failure of injured neurons to mount an effective regeneration program. Experimental in vivo models are of critical importance for exploring the potential clinical relevance of mechanistic findings and therapeutic innovations. However, the highly complex organization of the spinal cord, comprising multiple types of neurons, which form local neural networks, as well as short and long-ranging ascending or descending pathways, complicates detailed dissection of mechanistic processes, as well as identification/verification of therapeutic targets. Inducing different types of dorsal root injury at specific proximo-distal locations provide opportunities to distinguish key components underlying spinal cord regeneration failure. Crushing or cutting the dorsal root allows detailed analysis of the regeneration program of the sensory neurons, as well as of the glial response at the dorsal root-spinal cord interface without direct trauma to the spinal cord. At the same time, a lesion at this interface creates a localized injury of the spinal cord itself, but with an initial neuronal injury affecting only the axons of dorsal root ganglion neurons, and still a glial cell response closely resembling the one seen after direct spinal cord injury. In this review, we provide examples of previous research on dorsal root injury models and how these models can help future exploration of mechanisms and potential therapies for spinal cord injury repair.
Collapse
Affiliation(s)
- Håkan Aldskogius
- Laboratory of Regenertive Neurobiology, Biomedical Center, Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden;
| | | |
Collapse
|
15
|
Van Broeckhoven J, Sommer D, Dooley D, Hendrix S, Franssen AJPM. Macrophage phagocytosis after spinal cord injury: when friends become foes. Brain 2021; 144:2933-2945. [PMID: 34244729 DOI: 10.1093/brain/awab250] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/12/2021] [Accepted: 06/20/2021] [Indexed: 11/14/2022] Open
Abstract
After spinal cord injury (SCI), macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in SCI, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of SCI.
Collapse
Affiliation(s)
- Jana Van Broeckhoven
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Daniela Sommer
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Dearbhaile Dooley
- School of Medicine, Health Sciences Centre, University College Dublin, Belfield Dublin 4, Ireland.,UCD Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sven Hendrix
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,Medical School Hamburg, Hamburg, Germany
| | - Aimée J P M Franssen
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| |
Collapse
|
16
|
Ashayeri Ahmadabad R, Mirzaasgari Z, Gorji A, Khaleghi Ghadiri M. Toll-Like Receptor Signaling Pathways: Novel Therapeutic Targets for Cerebrovascular Disorders. Int J Mol Sci 2021; 22:ijms22116153. [PMID: 34200356 PMCID: PMC8201279 DOI: 10.3390/ijms22116153] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 12/11/2022] Open
Abstract
Toll-like receptors (TLRs), a class of pattern recognition proteins, play an integral role in the modulation of systemic inflammatory responses. Cerebrovascular diseases (CVDs) are a group of pathological conditions that temporarily or permanently affect the brain tissue mostly via the decrease of oxygen and glucose supply. TLRs have a critical role in the activation of inflammatory cascades following hypoxic-ischemic events and subsequently contribute to neuroprotective or detrimental effects of CVD-induced neuroinflammation. The TLR signaling pathway and downstream cascades trigger immune responses via the production and release of various inflammatory mediators. The present review describes the modulatory role of the TLR signaling pathway in the inflammatory responses developed following various CVDs and discusses the potential benefits of the modulation of different TLRs in the improvement of functional outcomes after brain ischemia.
Collapse
Affiliation(s)
- Rezan Ashayeri Ahmadabad
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1996835911, Iran; (R.A.A.); (Z.M.)
| | - Zahra Mirzaasgari
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1996835911, Iran; (R.A.A.); (Z.M.)
- Department of Neurology, Iran University of Medical Sciences, Tehran 1593747811, Iran
| | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1996835911, Iran; (R.A.A.); (Z.M.)
- Epilepsy Research Center, Westfälische Wilhelms-Universität, 48149 Münster, Germany
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
- Department of Neurosurgery, Westfälische Wilhelms-Universität, 48149 Münster, Germany;
- Department of Neurology, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
- Correspondence: ; Tel.: +49-251-8355564; Fax: +49-251-8347479
| | | |
Collapse
|
17
|
Nazareth L, St John J, Murtaza M, Ekberg J. Phagocytosis by Peripheral Glia: Importance for Nervous System Functions and Implications in Injury and Disease. Front Cell Dev Biol 2021; 9:660259. [PMID: 33898462 PMCID: PMC8060502 DOI: 10.3389/fcell.2021.660259] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
The central nervous system (CNS) has very limited capacity to regenerate after traumatic injury or disease. In contrast, the peripheral nervous system (PNS) has far greater capacity for regeneration. This difference can be partly attributed to variances in glial-mediated functions, such as axon guidance, structural support, secretion of growth factors and phagocytic activity. Due to their growth-promoting characteristic, transplantation of PNS glia has been trialed for neural repair. After peripheral nerve injuries, Schwann cells (SCs, the main PNS glia) phagocytose myelin debris and attract macrophages to the injury site to aid in debris clearance. One peripheral nerve, the olfactory nerve, is unique in that it continuously regenerates throughout life. The olfactory nerve glia, olfactory ensheathing cells (OECs), are the primary phagocytes within this nerve, continuously clearing axonal debris arising from the normal regeneration of the nerve and after injury. In contrast to SCs, OECs do not appear to attract macrophages. SCs and OECs also respond to and phagocytose bacteria, a function likely critical for tackling microbial invasion of the CNS via peripheral nerves. However, phagocytosis is not always effective; inflammation, aging and/or genetic factors may contribute to compromised phagocytic activity. Here, we highlight the diverse roles of SCs and OECs with the focus on their phagocytic activity under physiological and pathological conditions. We also explore why understanding the contribution of peripheral glia phagocytosis may provide us with translational strategies for achieving axonal regeneration of the injured nervous system and potentially for the treatment of certain neurological diseases.
Collapse
Affiliation(s)
- Lynn Nazareth
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia
| | - James St John
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Mariyam Murtaza
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Jenny Ekberg
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| |
Collapse
|
18
|
Peripheral inflammation promotes brain tau transmission via disrupting blood-brain barrier. Biosci Rep 2021; 40:222089. [PMID: 32043530 PMCID: PMC7033313 DOI: 10.1042/bsr20193629] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 12/15/2022] Open
Abstract
Abnormal aggregation of pathological tau protein is a neuropathological feature of Alzheimer's disease (AD). In the AD patients, the abnormal tau accumulation first appeared in entorhinal cortex (EC) and then propagated to the hippocampus with microglia activation and inflammation, but the mechanism is elusive. Here, we studied the role and mechanisms underlying periphery inflammation on brain tau transmission. By intraperitoneal injection of lipopolysaccharide (LPS) with brain medial entorhinal cortex (MEC)-specific overexpressing P301L human tau (P301L-hTau), we found that both acute and chronic administration of LPS remarkably promoted P301L-hTau transmission from MEC to the hippocampal subsets. Interestingly, the chronic LPS-induced P301L-hTau transmission was still apparent after blocking microglia activation. Further studies demonstrated that LPS disrupted the integrity of blood-brain barrier (BBB) and simultaneous intraperitoneal administration of glucocorticoid (GC) attenuated LPS-promoted P301L-hTau transmission. These data together suggest that a non-microglia-dependent BBB disruption contributes to peripheral LPS-promoted brain P301L-hTau transmission, therefore, maintaining the integrity of BBB can be a novel strategy for preventing pathological tau propagation in AD and other tauopathies.
Collapse
|
19
|
Tajbakhsh A, Read M, Barreto GE, Ávila-Rodriguez M, Gheibi-Hayat SM, Sahebkar A. Apoptotic neurons and amyloid-beta clearance by phagocytosis in Alzheimer's disease: Pathological mechanisms and therapeutic outlooks. Eur J Pharmacol 2021; 895:173873. [PMID: 33460611 DOI: 10.1016/j.ejphar.2021.173873] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 12/13/2022]
Abstract
Neuronal survival and axonal renewal following central nervous system damage and in neurodegenerative illnesses, such as Alzheimer's disease (AD), can be enhanced by fast clearance of neuronal apoptotic debris, as well as the removal of amyloid beta (Aβ) by phagocytic cells through the process of efferocytosis. This process quickly inhibits the release of proinflammatory and antigenic autoimmune constituents, enhancing the formation of a microenvironment vital for neuronal survival and axonal regeneration. Therefore, the detrimental features associated with microglial phagocytosis uncoupling, such as the accumulation of apoptotic cells, inflammation and phagoptosis, could exacerbate the pathology in brain disease. Some mechanisms of efferocytosis could be targeted by several promising agents, such as curcumin, URMC-099 and Y-P30, which have emerged as potential treatments for AD. This review aims to investigate and update the current research regarding the signaling molecules and pathways involved in efferocytosis and how these could be targeted as a potential therapy in AD.
Collapse
Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences & Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morgayn Read
- Department of Pharmacology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland
| | | | - Seyed Mohammad Gheibi-Hayat
- Department of Medical Biotechnology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.
| |
Collapse
|
20
|
Marshall KL, Farah MH. Axonal regeneration and sprouting as a potential therapeutic target for nervous system disorders. Neural Regen Res 2021; 16:1901-1910. [PMID: 33642358 PMCID: PMC8343323 DOI: 10.4103/1673-5374.308077] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Nervous system disorders are prevalent health issues that will only continue to increase in frequency as the population ages. Dying-back axonopathy is a hallmark of many neurologic diseases and leads to axonal disconnection from their targets, which in turn leads to functional impairment. During the course of many of neurologic diseases, axons can regenerate or sprout in an attempt to reconnect with the target and restore synapse function. In amyotrophic lateral sclerosis (ALS), distal motor axons retract from neuromuscular junctions early in the disease-course before significant motor neuron death. There is evidence of compensatory motor axon sprouting and reinnervation of neuromuscular junctions in ALS that is usually quickly overtaken by the disease course. Potential drugs that enhance compensatory sprouting and encourage reinnervation may slow symptom progression and retain muscle function for a longer period of time in ALS and in other diseases that exhibit dying-back axonopathy. There remain many outstanding questions as to the impact of distinct disease-causing mutations on axonal outgrowth and regeneration, especially in regards to motor neurons derived from patient induced pluripotent stem cells. Compartmentalized microfluidic chambers are powerful tools for studying the distal axons of human induced pluripotent stem cells-derived motor neurons, and have recently been used to demonstrate striking regeneration defects in human motor neurons harboring ALS disease-causing mutations. Modeling the human neuromuscular circuit with human induced pluripotent stem cells-derived motor neurons will be critical for developing drugs that enhance axonal regeneration, sprouting, and reinnervation of neuromuscular junctions. In this review we will discuss compensatory axonal sprouting as a potential therapeutic target for ALS, and the use of compartmentalized microfluidic devices to find drugs that enhance regeneration and axonal sprouting of motor axons.
Collapse
Affiliation(s)
| | - Mohamed H Farah
- Department of Neurology at Johns Hopkins School of Medicine, Baltimore, MD, USA
| |
Collapse
|
21
|
Lyu J, Jiang X, Leak RK, Shi Y, Hu X, Chen J. Microglial Responses to Brain Injury and Disease: Functional Diversity and New Opportunities. Transl Stroke Res 2020; 12:474-495. [PMID: 33128703 DOI: 10.1007/s12975-020-00857-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/27/2022]
Abstract
As an integral part of the innate immune system of the brain, resident microglia must react rapidly to the onset of brain injury and neurological disease. These dynamic cells then continue to shift their phenotype along a multidimensional continuum with overlapping pro- and anti-inflammatory states, allowing them to adapt to microenvironmental changes during the progression of brain disorders. However, the ability of microglia to shift phenotype through nimble molecular, structural, and functional changes comes at a cost, as the extreme pro-inflammatory states may prevent these professional phagocytes from clearing toxic debris and secreting tissue-repairing neurotrophic factors. Evolution has strongly favored heterogeneity in microglia in both the spatial and temporal dimensions-they can assume diverse roles in different brain regions, throughout the course of brain development and aging, and during the spatiotemporal progression of brain injuries and neurological diseases. Age and sex differences add further diversity to microglia functional status under physiological and pathological conditions. This article reviews recent advances in our knowledge of microglia with emphases on molecular mediators of phenotype shifts and functional diversity. We describe microglia-targeted therapeutic opportunities, including pharmacologic modulation of phenotype and repopulation of the brain with fresh microglia. With the advent of powerful new tools, research on microglia has recently accelerated in pace and may translate into potential therapeutics against brain injury and neurological disease.
Collapse
Affiliation(s)
- Junxuan Lyu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Xiaoyan Jiang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA.,Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA, 15261, USA
| | - Rehana K Leak
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Yejie Shi
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA.,Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA, 15261, USA
| | - Xiaoming Hu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA.,Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA, 15261, USA
| | - Jun Chen
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA. .,Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA, 15261, USA.
| |
Collapse
|
22
|
Buonfiglioli A, Efe IE, Guneykaya D, Ivanov A, Huang Y, Orlowski E, Krüger C, Deisz RA, Markovic D, Flüh C, Newman AG, Schneider UC, Beule D, Wolf SA, Dzaye O, Gutmann DH, Semtner M, Kettenmann H, Lehnardt S. let-7 MicroRNAs Regulate Microglial Function and Suppress Glioma Growth through Toll-Like Receptor 7. Cell Rep 2020; 29:3460-3471.e7. [PMID: 31825829 DOI: 10.1016/j.celrep.2019.11.029] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/08/2019] [Accepted: 11/06/2019] [Indexed: 12/20/2022] Open
Abstract
Microglia express Toll-like receptors (TLRs) that sense pathogen- and host-derived factors, including single-stranded RNA. In the brain, let-7 microRNA (miRNA) family members are abundantly expressed, and some have recently been shown to serve as TLR7 ligands. We investigated whether let-7 miRNA family members differentially control microglia biology in health and disease. We found that a subset of let-7 miRNA family members function as signaling molecules to induce microglial release of inflammatory cytokines, modulate antigen presentation, and attenuate cell migration in a TLR7-dependent manner. The capability of the let-7 miRNAs to control microglial function is sequence specific, mapping to a let-7 UUGU motif. In human and murine glioblastoma/glioma, let-7 miRNAs are differentially expressed and reduce murine GL261 glioma growth in the same sequence-specific fashion through microglial TLR7. Taken together, these data establish let-7 miRNAs as key TLR7 signaling activators that serve to regulate the diverse functions of microglia in health and glioma.
Collapse
Affiliation(s)
- Alice Buonfiglioli
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Ibrahim E Efe
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany; Department of Radiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Dilansu Guneykaya
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Andranik Ivanov
- Core Unit Bioinformatics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Yimin Huang
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Elisabeth Orlowski
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Christina Krüger
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Rudolf A Deisz
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Darko Markovic
- Department of Neurosurgery, Helios Clinics, 13125 Berlin, Germany
| | - Charlotte Flüh
- Department of Neurosurgery, University Medical Center Schleswig-Holstein (UKSH), 24105 Kiel, Germany
| | - Andrew G Newman
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Ulf C Schneider
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Dieter Beule
- Core Unit Bioinformatics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Susanne A Wolf
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Omar Dzaye
- Department of Radiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marcus Semtner
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Helmut Kettenmann
- Department of Cellular Neurosciences, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.
| | - Seija Lehnardt
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
| |
Collapse
|
23
|
Liu F, Cheng X, Zhong S, Liu C, Jolkkonen J, Zhang X, Liang Y, Liu Z, Zhao C. Communications Between Peripheral and the Brain-Resident Immune System in Neuronal Regeneration After Stroke. Front Immunol 2020; 11:1931. [PMID: 33042113 PMCID: PMC7530165 DOI: 10.3389/fimmu.2020.01931] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 07/17/2020] [Indexed: 12/14/2022] Open
Abstract
Cerebral ischemia may cause irreversible neural network damage and result in functional deficits. Targeting neuronal repair after stroke potentiates the formation of new connections, which can be translated into a better functional outcome. Innate and adaptive immune responses in the brain and the periphery triggered by ischemic damage participate in regulating neural repair after a stroke. Immune cells in the blood circulation and gut lymphatic tissues that have been shaped by immune components including gut microbiota and metabolites can infiltrate the ischemic brain and, once there, influence neuronal regeneration either directly or by modulating the properties of brain-resident immune cells. Immune-related signalings and metabolites from the gut microbiota can also directly alter the phenotypes of resident immune cells to promote neuronal regeneration. In this review, we discuss several potential mechanisms through which peripheral and brain-resident immune components can cooperate to promote first the resolution of neuroinflammation and subsequently to improved neural regeneration and a better functional recovery. We propose that new insights into discovery of regulators targeting pro-regenerative process in this complex neuro-immune network may lead to novel strategies for neuronal regeneration.
Collapse
Affiliation(s)
- Fangxi Liu
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Xi Cheng
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Shanshan Zhong
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Chang Liu
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Jukka Jolkkonen
- A.I. Virtanen Institute and Institute of Clinical Medicine/Neurology, University of Eastern Finland, Kuopio, Finland
| | - Xiuchun Zhang
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Yifan Liang
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Zhouyang Liu
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Chuansheng Zhao
- Neurology, The First Hospital of China Medical University, Shenyang, China.,Stroke Center, The First Hospital of China Medical University, Shenyang, China
| |
Collapse
|
24
|
Rodríguez-Gómez JA, Kavanagh E, Engskog-Vlachos P, Engskog MK, Herrera AJ, Espinosa-Oliva AM, Joseph B, Hajji N, Venero JL, Burguillos MA. Microglia: Agents of the CNS Pro-Inflammatory Response. Cells 2020; 9:E1717. [PMID: 32709045 PMCID: PMC7407646 DOI: 10.3390/cells9071717] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/21/2022] Open
Abstract
The pro-inflammatory immune response driven by microglia is a key contributor to the pathogenesis of several neurodegenerative diseases. Though the research of microglia spans over a century, the last two decades have increased our understanding exponentially. Here, we discuss the phenotypic transformation from homeostatic microglia towards reactive microglia, initiated by specific ligand binding to pattern recognition receptors including toll-like receptor-4 (TLR4) or triggering receptors expressed on myeloid cells-2 (TREM2), as well as pro-inflammatory signaling pathways triggered such as the caspase-mediated immune response. Additionally, new research disciplines such as epigenetics and immunometabolism have provided us with a more holistic view of how changes in DNA methylation, microRNAs, and the metabolome may influence the pro-inflammatory response. This review aimed to discuss our current knowledge of pro-inflammatory microglia from different angles, including recent research highlights such as the role of exosomes in spreading neuroinflammation and emerging techniques in microglia research including positron emission tomography (PET) scanning and the use of human microglia generated from induced pluripotent stem cells (iPSCs). Finally, we also discuss current thoughts on the impact of pro-inflammatory microglia in neurodegenerative diseases.
Collapse
Affiliation(s)
- José A. Rodríguez-Gómez
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Medical Physiology and Biophysics, Faculty of Medicine, University of Seville, 41009 Sevilla, Spain
| | - Edel Kavanagh
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Pinelopi Engskog-Vlachos
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Mikael K.R. Engskog
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden;
| | - Antonio J. Herrera
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Ana M. Espinosa-Oliva
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Bertrand Joseph
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Nabil Hajji
- Division of Brain Sciences, The John Fulcher Molecular Neuro-Oncology Laboratory, Imperial College London, London W12 ONN, UK;
| | - José L. Venero
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Miguel A. Burguillos
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| |
Collapse
|
25
|
Famakin BM, Vemuganti R. Toll-Like Receptor 4 Signaling in Focal Cerebral Ischemia: a Focus on the Neurovascular Unit. Mol Neurobiol 2020; 57:2690-2701. [PMID: 32306272 DOI: 10.1007/s12035-020-01906-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/19/2020] [Indexed: 12/14/2022]
Abstract
A robust innate immune activation leads to downstream expression of inflammatory mediators that amplify tissue damage and consequently increase the morbidity after stroke. The Toll-like receptor 4 (TLR4) pathway is a major innate immune pathway activated acutely and chronically after stroke. Hence, understanding the intricacies of the temporal profile, specific control points, and cellular specificity of TLR4 activation is crucial for the development of any novel therapeutics targeting the endogenous innate immune response after focal cerebral ischemia. The goal of this review is to summarize the current findings related to TLR4 signaling after stroke with a specific focus on the components of the neurovascular unit such as astrocytes, neurons, endothelial cells, and pericytes. In addition, this review will examine the effects of focal cerebral ischemia on interaction of these neurovascular unit components.
Collapse
Affiliation(s)
| | - R Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
- William S. Middleton VA Hospital, Madison, WI, USA
| |
Collapse
|
26
|
Wen RX, Shen H, Huang SX, Wang LP, Li ZW, Peng P, Mamtilahun M, Tang YH, Shen FX, Tian HL, Yang GY, Zhang ZJ. P2Y6 receptor inhibition aggravates ischemic brain injury by reducing microglial phagocytosis. CNS Neurosci Ther 2020; 26:416-429. [PMID: 32154670 PMCID: PMC7080436 DOI: 10.1111/cns.13296] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/01/2020] [Accepted: 02/01/2020] [Indexed: 02/06/2023] Open
Abstract
Introduction Clearance of damaged cells and debris is beneficial for the functional recovery after ischemic brain injury. However, the specific phagocytic receptor that mediates microglial phagocytosis after ischemic stroke is unknown. Aim To investigate whether P2Y6 receptor‐mediated microglial phagocytosis is beneficial for the debris clearance and functional recovery after ischemic stroke. Results The expression of the P2Y6 receptor in microglia increased within 3 days after transient middle cerebral artery occlusion. Inhibition of microglial phagocytosis by the selective inhibitor MRS2578 enlarged the brain atrophy and edema volume after ischemic stroke, subsequently aggravated neurological function as measured by modified neurological severity scores and Grid walking test. MRS2578 treatment had no effect on the expression of IL‐1α, IL‐1β, IL‐6, IL‐10, TNF‐α, TGF‐β, and MPO after ischemic stroke. Finally, we found that the expression of myosin light chain kinase decreased after microglial phagocytosis inhibition in the ischemic mouse brain, which suggested that myosin light chain kinase was involved in P2Y6 receptor‐mediated phagocytosis. Conclusion Our results indicate that P2Y6 receptor‐mediated microglial phagocytosis plays a beneficial role during the acute stage of ischemic stroke, which can be a therapeutic target for ischemic stroke.
Collapse
Affiliation(s)
- Ruo-Xue Wen
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Hui Shen
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Shu-Xian Huang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Li-Ping Wang
- Department of Neurology, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Zong-Wei Li
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Peng Peng
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Muyassar Mamtilahun
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yao-Hui Tang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Fan-Xia Shen
- Department of Neurology, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Heng-Li Tian
- Department of Neurosurgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,Department of Neurology, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Zhi-Jun Zhang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
27
|
The roles played by TLR4 in the pathogenesis of multiple sclerosis; A systematic review article. Immunol Lett 2020; 220:63-70. [PMID: 32032617 DOI: 10.1016/j.imlet.2020.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/19/2020] [Accepted: 02/03/2020] [Indexed: 12/15/2022]
Abstract
Multiple sclerosis (MS) is a world-wide pro-inflammatory based disease, which is prevalent among young individuals. The etiology of the disease and its related complications are yet to be clarified. It has been hypothesized that environmental factors, including pathogen-associated molecular patterns (PAMPs) and the internal factors such as damage-associated molecular patterns (DAMPs), may be the most important inducers/stimulators of the disorder and its related complications. Previous investigations proved that pathogen recognition receptors (PRRs) are the main sensors for the PAMPs and DAMPs. Therefore, it seems that the PRRs have been considered to be the plausible molecules participating in the etiology of MS. Toll-like receptors (TLRs) have been the widely studied PRRs and their roles have been documented in human-related diseases. TLR4 is the main PRR expressed on the cell surface of several immune cells including macrophages and dendritic cells. Several investigations reported that TLR4 to be the main molecule involved in the pathogenesis of pro-inflammatory based diseases. Thus, it has been hypothesized that TLR4 may be a part of the MS puzzle. This review article discusses the role of TLR4 in the MS pathogenesis using recent in vitro and in vivo investigations.
Collapse
|
28
|
Hou LS, Cui ZY, Sun P, Piao HQ, Han X, Song J, Wang G, Zheng S, Dong XX, Gao L, Zhu Y, Lian LH, Nan JX, Wu YL. Rutin mitigates hepatic fibrogenesis and inflammation through targeting TLR4 and P2X7 receptor signaling pathway in vitro and in vivo. J Funct Foods 2020. [DOI: 10.1016/j.jff.2019.103700] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
|
29
|
Leitner GR, Wenzel TJ, Marshall N, Gates EJ, Klegeris A. Targeting toll-like receptor 4 to modulate neuroinflammation in central nervous system disorders. Expert Opin Ther Targets 2019; 23:865-882. [PMID: 31580163 DOI: 10.1080/14728222.2019.1676416] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Introduction: Adverse immune activation contributes to many central nervous system (CNS) disorders. All main CNS cell types express toll-like receptor 4 (TLR 4). This receptor is critical for a myriad of immune functions such as cytokine secretion and phagocytic activity of microglia; however, imbalances in TLR 4 activation can contribute to the progression of neurodegenerative diseases. Areas covered: We considered available evidence implicating TLR 4 activation in the following CNS pathologies: Alzheimer's disease, Parkinson's disease, ischemic stroke, traumatic brain injury, multiple sclerosis, multiple systems atrophy, and Huntington's disease. We reviewed studies reporting effects of TLR 4-specific antagonists and agonists in models of peripheral and CNS diseases from the perspective of possible future use of TLR 4 ligands in CNS disorders. Expert opinion: TLR 4-specific antagonists could suppress neuroinflammation by reducing overproduction of inflammatory mediators; however, they may interfere with protein clearance mechanisms and myelination. Agonists that specifically activate myeloid differentiation primary-response protein 88 (MyD88)-independent pathway of TLR 4 signaling could facilitate beneficial glial phagocytic activity with limited activity as inducers of proinflammatory mediators. Deciphering the disease stage-specific involvement of TLR 4 in CNS pathologies is crucial for the future clinical development of TLR 4 agonists and antagonists.
Collapse
Affiliation(s)
- Gunnar R Leitner
- Department of Biology, University of British Columbia Okanagan Campus , Kelowna , British Columbia , Canada
| | - Tyler J Wenzel
- Department of Biology, University of British Columbia Okanagan Campus , Kelowna , British Columbia , Canada
| | - Nick Marshall
- Department of Biology, University of British Columbia Okanagan Campus , Kelowna , British Columbia , Canada
| | - Ellen J Gates
- Department of Biology, University of British Columbia Okanagan Campus , Kelowna , British Columbia , Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus , Kelowna , British Columbia , Canada
| |
Collapse
|
30
|
Sophocarpine Attenuates Chronic Constriction Sciatic Nerve Injury-induced Neuropathic Pain in Mice by Inhibiting the HMGB1/TLR4/NF-κB Signaling Pathway. IRANIAN RED CRESCENT MEDICAL JOURNAL 2019. [DOI: 10.5812/ircmj.94716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
31
|
Haage V, Elmadany N, Roll L, Faissner A, Gutmann DH, Semtner M, Kettenmann H. Tenascin C regulates multiple microglial functions involving TLR4 signaling and HDAC1. Brain Behav Immun 2019; 81:470-483. [PMID: 31271872 DOI: 10.1016/j.bbi.2019.06.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/27/2019] [Accepted: 06/29/2019] [Indexed: 01/15/2023] Open
Abstract
Tenascin C (Tnc) is an extracellular matrix glycoprotein, expressed in the CNS during development, as well as in the setting of inflammation, fibrosis and cancer, which operates as an activator of Toll-like receptor 4 (TLR4). Although TLR4 is highly expressed in microglia, the effect of Tnc on microglia has not been elucidated to date. Herein, we demonstrate that Tnc regulates microglial phagocytic activity at an early postnatal age (P4), and that this process is partially dependent on microglial TLR4 expression. We further show that Tnc regulates proinflammatory cytokine/chemokine production, chemotaxis and phagocytosis in primary microglia in a TLR4-dependent fashion. Moreover, Tnc induces histone-deacetylase 1 (HDAC1) expression in microglia, such that HDAC1 inhibition by MS-275 decreases Tnc-induced microglial IL-6 and TNF-α production. Finally, Tnc-/- cortical microglia have reduced HDAC1 expression levels at P4. Taken together, these findings establish Tnc as a regulator of microglia function during early postnatal development.
Collapse
Affiliation(s)
- Verena Haage
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Nirmeen Elmadany
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Lars Roll
- Zellmorphologie und Molekulare Neurobiologie, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, Bochum, Nordrhein-Wastfalen 44801, Germany
| | - Andreas Faissner
- Zellmorphologie und Molekulare Neurobiologie, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, Bochum, Nordrhein-Wastfalen 44801, Germany
| | - David H Gutmann
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany.
| |
Collapse
|
32
|
McDonough A, Weinstein JR. The role of microglia in ischemic preconditioning. Glia 2019; 68:455-471. [PMID: 31386233 DOI: 10.1002/glia.23695] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/20/2019] [Accepted: 07/23/2019] [Indexed: 12/22/2022]
Abstract
Ischemic preconditioning (IPC) is an experimental phenomenon in which a brief ischemic stimulus confers protection against a subsequent prolonged ischemic event. Initially thought to be due to mechanistic changes in neurons, our understanding of IPC has evolved to encompass a global reprogramming of the Central Nervous System (CNS) after transient ischemia/reperfusion that requires innate immune signaling pathways including Toll-like receptors (TLRs) and Type I interferons. Microglia are the CNS resident neuroimmune cells that express these key innate immune receptors. Studies suggest that microglia are required for IPC-mediated neuronal and axonal protection. Multiple paradigms targeting TLRs have converged on a distinctive Type I interferon response in microglia that is critical for preconditioning-mediated protection against ischemia. These pathways can be targeted through administration of TLR agonists, cytokines including interferon-β, and pharmaceutical agents that induce preconditioning through cross-tolerance mechanisms. Transcriptomic analyses and single cell RNA studies point to specific gene expression signatures in microglia that functionally shift these mutable cells to an immunomodulatory or protective phenotype. Although there are technological challenges and gaps in knowledge to overcome, the targeting of specific molecular signaling pathways in microglia is a promising direction for development of novel and effective pharmacotherapies for stroke. Studies on preconditioning in animal models, including nonhuman primates, show promise as prophylactic preconditioning treatments for selected at risk patient populations. In addition, our growing understanding of the mechanisms of IPC-mediated protection is identifying novel cellular and molecular targets for therapeutic interventions that could apply broadly to both acute stroke and chronic vascular cognitive impairment patients.
Collapse
Affiliation(s)
- Ashley McDonough
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington.,Department of Neurological Surgery, School of Medicine, University of Washington, Seattle, Washington
| |
Collapse
|
33
|
Smolders SMT, Kessels S, Vangansewinkel T, Rigo JM, Legendre P, Brône B. Microglia: Brain cells on the move. Prog Neurobiol 2019; 178:101612. [PMID: 30954517 DOI: 10.1016/j.pneurobio.2019.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, tremendous progress has been made in understanding the biology of microglia - i.e. the fascinating immigrated resident immune cell population of the central nervous system (CNS). Recent literature reviews have largely dealt with the plentiful functions of microglia in CNS homeostasis, development and pathology, and the influences of sex and the microbiome. In this review, the intriguing aspect of their physical plasticity during CNS development will get specific attention. Microglia move around (mobility) and reshape their processes (motility). Microglial migration into and inside the CNS is most prominent throughout development and consequently most of the data described in this review concern mobility and motility in the changing environment of the developing brain. Here, we first define microglia based on their highly specialized age- and region-dependent gene expression signature and associated functional heterogeneity. Next, we describe their origin, the migration route of immature microglial cells towards the CNS, the mechanisms underlying their invasion of the CNS, and their spatiotemporal localization and surveying behaviour inside the developing CNS. These processes are dependent on microglial mobility and motility which are determined by the microenvironment of the CNS. Therefore, we further zoom in on the changing environment during CNS development. We elaborate on the extracellular matrix and the respective integrin receptors on microglia and we discuss the purinergic and molecular signalling in microglial mobility. In the last section, we discuss the physiological and pathological functions of microglia in which mobility and motility are involved to stress the importance of microglial 'movement'.
Collapse
Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium; INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Pascal Legendre
- INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | |
Collapse
|
34
|
Noailles A, Kutsyr O, Maneu V, Ortuño-Lizarán I, Campello L, de Juan E, Gómez-Vicente V, Cuenca N, Lax P. The Absence of Toll-Like Receptor 4 Mildly Affects the Structure and Function in the Adult Mouse Retina. Front Cell Neurosci 2019; 13:59. [PMID: 30873007 PMCID: PMC6401850 DOI: 10.3389/fncel.2019.00059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/05/2019] [Indexed: 12/26/2022] Open
Abstract
The innate immune Toll-like receptor (TLR) family plays essential roles in cell proliferation, survival and function of the central nervous system. However, the way in which TLRs contribute to the development and maintenance of proper retinal structure and function remains uncertain. In this work, we assess the effect of genetic TLR4 deletion on the morphology and function of the retina in mice. Visual acuity and retinal responsiveness were evaluated in TLR4 knockout and wild type C57BL/6J control mice by means of an optomotor test and electroretinography, respectively, from P20 to P360. Retinal structure was also analyzed in both strains using confocal and electron microscopy. ERG data showed impaired retinal responsiveness in TLR4 KO mice, in comparison to wild type animals. The amplitudes of the scotopic a-waves were less pronounced in TLR4-deficient mice than in wild-type animals from P30 to P360, and TLR4 KO mice presented scotopic b-wave amplitudes smaller than those of age-matched control mice at all ages studied (P20 to P360). Visual acuity was also relatively poorer in TLR4 KO as compared to C57BL/6J mice from P20 to P360, with significant differences at P30 and P60. Immunohistochemical analysis of retinal vertical sections showed no differences between TLR4 KO and C57BL/6J mice, in terms of either photoreceptor number or photoreceptor structure. Horizontal cells also demonstrated no morphological differences between TLR4 KO and wild-type mice. However, TLR4 KO mice exhibited a lower density of bipolar cells (15% less at P30) and thus fewer bipolar cell dendrites than the wild type control mouse, even though both confocal and electron microscopy images showed no morphologic abnormalities in the synaptic contacts between the photoreceptors and second order neurons. Microglial cell density was significantly lower (26% less at P30) in TLR4 KO mice as compared to wild-type control mice. These results suggest that TLR4 deletion causes functional alterations in terms of visual response and acuity, probably through the loss of bipolar cells and microglia, but this receptor is not essential for the processing of visual information in the retina.
Collapse
Affiliation(s)
- Agustina Noailles
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Isabel Ortuño-Lizarán
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Emilio de Juan
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Violeta Gómez-Vicente
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain.,Institute Ramón Margalef, University of Alicante, Alicante, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| |
Collapse
|
35
|
McLaughlin CN, Perry-Richardson JJ, Coutinho-Budd JC, Broihier HT. Dying Neurons Utilize Innate Immune Signaling to Prime Glia for Phagocytosis during Development. Dev Cell 2019; 48:506-522.e6. [PMID: 30745142 DOI: 10.1016/j.devcel.2018.12.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/19/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023]
Abstract
Glia continuously survey neuronal health during development, providing trophic support to healthy neurons while rapidly engulfing dying ones. These diametrically opposed functions necessitate a foolproof mechanism enabling glia to unambiguously identify those neurons to support versus those to engulf. To ensure specificity, glia are proposed to interact with dying neurons via a series of carefully choreographed steps. However, these crucial interactions are largely obscure. Here we show that dying neurons and glia communicate via Toll-receptor-regulated innate immune signaling. Neuronal apoptosis drives processing and activation of the Toll-6 ligand, Spätzle5. This cue activates a dSARM-mediated Toll-6 transcriptional pathway in glia, which controls the expression of the Draper engulfment receptor. Pathway loss drives early-onset neurodegeneration, underscoring its functional importance. Our results identify an upstream priming signal that prepares glia for phagocytosis. Thus, a core innate immune pathway plays an unprecedented role setting the valence of neuron-glia interactions during development.
Collapse
Affiliation(s)
- Colleen N McLaughlin
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| | - Jahci J Perry-Richardson
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | | | - Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| |
Collapse
|
36
|
Konishi H, Kiyama H, Ueno M. Dual functions of microglia in the formation and refinement of neural circuits during development. Int J Dev Neurosci 2018; 77:18-25. [DOI: 10.1016/j.ijdevneu.2018.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/20/2018] [Accepted: 09/30/2018] [Indexed: 12/29/2022] Open
Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and NeuroscienceNagoya University Graduate School of MedicineNagoya466‐8550Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and NeuroscienceNagoya University Graduate School of MedicineNagoya466‐8550Japan
| | - Masaki Ueno
- Department of System Pathology for Neurological DisordersBrain Research InstituteNiigata UniversityNiigata951‐8585Japan
| |
Collapse
|
37
|
Toll-Like Receptor 4 (TLR4) Expression Affects Schwann Cell Behavior in vitro. Sci Rep 2018; 8:11179. [PMID: 30046125 PMCID: PMC6060163 DOI: 10.1038/s41598-018-28516-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 06/25/2018] [Indexed: 12/12/2022] Open
Abstract
Peripheral nerve injury can result in the decreased quality of life and bring us economic burden on society and individuals. Wallerian degeneration (WD) is critical for nerve degeneration and regeneration, but the mechanisms of WD are still elusive. Here, we report the effect of Toll-like receptor 4 (TLR4) on cultured Schwann cells (SCs) in vitro. The data showed that TLR4 expression was up-regulated after sciatic nerve injury of rat. TLR4 was expressed in cultured SCs. Enhanced or silenced expression of TLR4 affected SC proliferation, migration, apoptosis and relative gene expression. Furthermore, altered expression of TLR4 resulted in expression changes in c-Jun, ERK and catenin but not AKT and c-Fos pathways in SCs. These results suggested that TLR4 may be an important effective target in peripheral nerve degeneration and/or regeneration during WD in future investigations.
Collapse
|
38
|
Song S, Wang S, Pigott VM, Jiang T, Foley LM, Mishra A, Nayak R, Zhu W, Begum G, Shi Y, Carney KE, Hitchens TK, Shull GE, Sun D. Selective role of Na + /H + exchanger in Cx3cr1 + microglial activation, white matter demyelination, and post-stroke function recovery. Glia 2018; 66:2279-2298. [PMID: 30043461 DOI: 10.1002/glia.23456] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/27/2018] [Accepted: 04/24/2018] [Indexed: 12/22/2022]
Abstract
Na+ /H+ exchanger (NHE1) activation is required for multiple microglial functions. We investigated effects of selective deletion of microglial Nhe1 in Cx3cr1-CreER ;Nhe1f/f mice on neuroinflammation and tissue repair after ischemic stroke. Infarct volume was similar in corn oil or tamoxifen (Tam)-treated mice at 48 hr and 14 days post-stroke. However, the Tam-treated mice showed significantly higher survival rate and faster neurological function recovery during day 1-14 post-stroke. Deletion of microglial Nhe1 prevented the elevation of CD11b+ /CD45low-med microglia in the ischemic hemisphere at day 3 post-stroke, but stimulated expression of Ym1, CD68, TGF-β, IL-10, decreased expression of CD86 and IL-1β, and reduced GFAP+ reactive astrocytes. Moreover, at day 14 post-stroke, enhanced white matter myelination was detected in the microglial Nhe1 deleted mice. In comparison, neuronal Nhe1-null mice (the CamKII-Cre+/- ;Nhe1f/f mice) showed a significant reduction in both acute and subacute infarct volume, along with increased survival rate and moderate neurological function recovery. However, these neuronal Nhe1-null mice did not exhibit reduced activation of CD11b+ /CD45low-med microglia or CD11b+ /CD45hi macrophages in the ischemic brains, and they exhibited no reductions in white matter lesions. Taken together, this study demonstrated that deletion of microglial and neuronal Nhe1 had differential effects on ischemic brain damage. Microglial NHE1 is involved in pro-inflammatory responses during post-stroke brain tissue repair. In contrast, neuronal NHE1 activation is directly associated with the acute ischemic neuronal injury but not inflammation. Our study reveals that NHE1 protein is a potential therapeutic target critical for differential regulation of ischemic neuronal injury, demyelination and tissue repair.
Collapse
Affiliation(s)
- Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Shaoxia Wang
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Victoria M Pigott
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Tong Jiang
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Lesley M Foley
- Animal Imaging Center, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Abhishek Mishra
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Rachana Nayak
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Wen Zhu
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Yejie Shi
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Karen E Carney
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - T Kevin Hitchens
- Animal Imaging Center, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio, 45267
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania
| |
Collapse
|
39
|
Toll-Like Receptors: Regulators of the Immune Response in the Human Gut. Nutrients 2018; 10:nu10020203. [PMID: 29438282 PMCID: PMC5852779 DOI: 10.3390/nu10020203] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/08/2018] [Accepted: 02/09/2018] [Indexed: 12/28/2022] Open
Abstract
Toll-like receptors (TLRs) are powerful molecular regulators by which the immune system may "sense" the environment and protect the host from pathogens or endogenous threats. In mammalian cells, several TLRs were identified with a tissue and cell type-specific distribution. Understanding the functions of specific TLRs is crucial for the development and discovery of compounds useful to maintaining or re-establishing homeostasis in the gastrointestinal tract (GIT). Due to their relevance in regulating the inflammatory response in the GIT, we will focus here on TLR2, TLR4, and TLR5. In particular, we describe (a) the molecular pathways activated by the stimulation of these receptors with their known bacterial ligands; (b) the non-bacterial ligands known to interact directly with TLR2 and TLR4 and their soluble forms. The scope of this minireview is to highlight the importance of bacterial and non-bacterial compounds in affecting the gut immune functions via the activation of the TLRs.
Collapse
|
40
|
Zhao H, Chen Y, Feng H. P2X7 Receptor-Associated Programmed Cell Death in the Pathophysiology of Hemorrhagic Stroke. Curr Neuropharmacol 2018; 16:1282-1295. [PMID: 29766811 PMCID: PMC6251042 DOI: 10.2174/1570159x16666180516094500] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 07/17/2017] [Accepted: 02/28/2018] [Indexed: 12/20/2022] Open
Abstract
Hemorrhagic stroke is a life-threatening disease characterized by a sudden rupture of cerebral blood vessels, and cell death is widely believed to occur after exposure to blood metabolites or subsequently damaged cells. Recently, programmed cell death, such as apoptosis, autophagy, necroptosis, pyroptosis, and ferroptosis, has been demonstrated to play crucial roles in the pathophysiology of stroke. However, the detailed mechanisms of these novel kinds of cell death are still unclear. The P2X7 receptor, previously known for its cytotoxic activity, is an ATP-gated, nonselective cation channel that belongs to the family of ionotropic P2X receptors. Evolving evidence indicates that the P2X7 receptor plays a pivotal role in central nervous system pathology; genetic deletion and pharmacological blockade of the P2X7 receptor provide neuroprotection in various neurological disorders, including intracerebral hemorrhage and subarachnoid hemorrhage. The P2X7 receptor may regulate programmed cell death via (I) exocytosis of secretory lysosomes, (II) exocytosis of autophagosomes or autophagolysosomes during formation of the initial autophagic isolation membrane or omegasome, and (III) direct release of cytosolic IL-1β secondary to regulated cell death by pyroptosis or necroptosis. In this review, we present an overview of P2X7 receptor- associated programmed cell death for further understanding of hemorrhagic stroke pathophysiology, as well as potential therapeutic targets for its treatment.
Collapse
Affiliation(s)
- Hengli Zhao
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China
| | - Yujie Chen
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China
| |
Collapse
|
41
|
Kaur C, Rathnasamy G, Ling EA. Biology of Microglia in the Developing Brain. J Neuropathol Exp Neurol 2017; 76:736-753. [PMID: 28859332 DOI: 10.1093/jnen/nlx056] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Microglia exist in different morphological forms in the developing brain. They show a small cell body with scanty cytoplasm with many branching processes in the grey matter of the developing brain. However, in the white matter such as the corpus callosum where the unmyelinated axons are loosely organized, they appear in an amoeboid form having a round cell body endowed with copious cytoplasm rich in organelles. The amoeboid cells eventually transform into ramified microglia in the second postnatal week when the tissue becomes more compact with the onset of myelination. Microglia serve as immunocompetent macrophages that act as neuropathology sensors to detect and respond swiftly to subtle changes in the brain tissues in pathological conditions. Microglial functions are broadly considered as protective in the normal brain development as they phagocytose dead cells and sculpt neuronal connections by pruning excess axons and synapses. They also secrete a number of trophic factors such as insulin-like growth factor-1 and transforming growth factor-β among many others that are involved in neuronal and oligodendrocyte survival. On the other hand, microglial cells when activated produce a plethora of molecules such as proinflammatory cytokines, chemokines, reactive oxygen species, and nitric oxide that are implicated in the pathogenesis of many pathological conditions such as epilepsy, cerebral palsy, autism, and perinatal hypoxic-ischemic brain injury. Although many studies have investigated the origin and functions of the microglia in the developing brain, in-depth in vivo studies along with analysis of their transcriptome and epigenetic changes need to be undertaken to elucidate their full potential be it protective or neurotoxic. This would lead to a better understanding of their roles in the healthy and diseased developing brain and advancement of therapeutic strategies to target microglia-mediated neurotoxicity.
Collapse
Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| |
Collapse
|
42
|
TLR4 Deficiency Impairs Oligodendrocyte Formation in the Injured Spinal Cord. J Neurosci 2017; 36:6352-64. [PMID: 27277810 DOI: 10.1523/jneurosci.0353-16.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Acute oligodendrocyte (OL) death after traumatic spinal cord injury (SCI) is followed by robust neuron-glial antigen 2 (NG2)-positive OL progenitor proliferation and differentiation into new OLs. Inflammatory mediators are prevalent during both phases and can influence the fate of NG2 cells and OLs. Specifically, toll-like receptor (TLR) 4 signaling induces OL genesis in the naive spinal cord, and lack of TLR4 signaling impairs white matter sparing and functional recovery after SCI. Therefore, we hypothesized that TLR4 signaling may regulate oligodendrogenesis after SCI. C3H/HeJ (TLR4-deficient) and control (C3H/HeOuJ) mice received a moderate midthoracic spinal contusion. TLR4-deficient mice showed worse functional recovery and reduced OL numbers compared with controls at 24 h after injury through chronic time points. Acute OL loss was accompanied by reduced ferritin expression, which is regulated by TLR4 and needed for effective iron storage. TLR4-deficient injured spinal cords also displayed features consistent with reduced OL genesis, including reduced NG2 expression, fewer BrdU-positive OLs, altered BMP4 signaling and inhibitor of differentiation 4 (ID4) expression, and delayed myelin phagocytosis. Expression of several factors, including IGF-1, FGF2, IL-1β, and PDGF-A, was altered in TLR4-deficient injured spinal cords compared with wild types. Together, these data show that TLR4 signaling after SCI is important for OL lineage cell sparing and replacement, as well as in regulating cytokine and growth factor expression. These results highlight new roles for TLR4 in endogenous SCI repair and emphasize that altering the function of a single immune-related receptor can dramatically change the reparative responses of multiple cellular constituents in the injured CNS milieu. SIGNIFICANCE STATEMENT Myelinating cells of the CNS [oligodendrocytes (OLs)] are killed for several weeks after traumatic spinal cord injury (SCI), but they are replaced by resident progenitor cells. How the concurrent inflammatory signaling affects this endogenous reparative response is unclear. Here, we provide evidence that immune receptor toll-like receptor 4 (TLR4) supports OL lineage cell sparing, long-term OL and OL progenitor replacement, and chronic functional recovery. We show that TLR4 signaling is essential for acute iron storage, regulating cytokine and growth factor expression, and efficient myelin debris clearance, all of which influence OL replacement. Importantly, the current study reveals that a single immune receptor is essential for repair responses after SCI, and the potential mechanisms of this beneficial effect likely change over time after injury.
Collapse
|
43
|
Klein RS, Hunter CA. Protective and Pathological Immunity during Central Nervous System Infections. Immunity 2017; 46:891-909. [PMID: 28636958 PMCID: PMC5662000 DOI: 10.1016/j.immuni.2017.06.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/05/2017] [Accepted: 06/05/2017] [Indexed: 02/08/2023]
Abstract
The concept of immune privilege of the central nervous system (CNS) has dominated the study of inflammatory processes in the brain. However, clinically relevant models have highlighted that innate pathways limit pathogen invasion of the CNS and adaptive immunity mediates control of many neural infections. As protective responses can result in bystander damage, there are regulatory mechanisms that balance protective and pathological inflammation, but these mechanisms might also allow microbial persistence. The focus of this review is to consider the host-pathogen interactions that influence neurotropic infections and to highlight advances in our understanding of innate and adaptive mechanisms of resistance as key determinants of the outcome of CNS infection. Advances in these areas have broadened our comprehension of how the immune system functions in the brain and can readily overcome immune privilege.
Collapse
Affiliation(s)
- Robyn S Klein
- Departments of Medicine, Pathology and Immunology, Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
44
|
Microglial Interferon Signaling and White Matter. Neurochem Res 2017; 42:2625-2638. [PMID: 28540600 DOI: 10.1007/s11064-017-2307-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 05/14/2017] [Accepted: 05/18/2017] [Indexed: 01/17/2023]
Abstract
Microglia, the resident immune cells of the CNS, are primary regulators of the neuroimmune response to injury. Type I interferons (IFNs), including the IFNαs and IFNβ, are key cytokines in the innate immune system. Their activity is implicated in the regulation of microglial function both during development and in response to neuroinflammation, ischemia, and neurodegeneration. Data from numerous studies in multiple sclerosis (MS) and stroke suggest that type I IFNs can modulate the microglial phenotype, influence the overall neuroimmune milieu, regulate phagocytosis, and affect blood-brain barrier integrity. All of these IFN-induced effects result in numerous downstream consequences on white matter pathology and microglial reactivity. Dysregulation of IFN signaling in mouse models with genetic deficiency in ubiquitin specific protease 18 (USP18) leads to a severe neurological phenotype and neuropathological changes that include white matter microgliosis and pro-inflammatory gene expression in dystrophic microglia. A class of genetic disorders in humans, referred to as pseudo-TORCH syndrome (PTS) for the clinical resemblance to infection-induced TORCH syndrome, also show dysregulation of IFN signaling, which leads to severe neurological developmental disease. In these disorders, the excessive activation of IFN signaling during CNS development results in a destructive interferonopathy with similar induction of microglial dysfunction as seen in USP18 deficient mice. Other recent studies implicate "microgliopathies" more broadly in neurological disorders including Alzheimer's disease (AD) and MS, suggesting that microglia are a potential therapeutic target for disease prevention and/or treatment, with interferon signaling playing a key role in regulating the microglial phenotype.
Collapse
|
45
|
Church JS, Milich LM, Lerch JK, Popovich PG, McTigue DM. E6020, a synthetic TLR4 agonist, accelerates myelin debris clearance, Schwann cell infiltration, and remyelination in the rat spinal cord. Glia 2017; 65:883-899. [PMID: 28251686 DOI: 10.1002/glia.23132] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 12/26/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are present throughout the adult brain and spinal cord and can replace oligodendrocytes lost to injury, aging, or disease. Their differentiation, however, is inhibited by myelin debris, making clearance of this debris an important step for cellular repair following demyelination. In models of peripheral nerve injury, TLR4 activation by lipopolysaccharide (LPS) promotes macrophage phagocytosis of debris. Here we tested whether the novel synthetic TLR4 agonist E6020, a Lipid A mimetic, promotes myelin debris clearance and remyelination in spinal cord white matter following lysolecithin-induced demyelination. In vitro, E6020 induced TLR4-dependent cytokine expression (TNFα, IL1β, IL-6) and NF-κB signaling, albeit at ∼10-fold reduced potency compared to LPS. Microinjection of E6020 into the intact rat spinal cord gray/white matter border induced macrophage activation, OPC proliferation, and robust oligodendrogenesis, similar to what we described previously using an intraspinal LPS microinjection model. Finally, a single co-injection of E6020 with lysolecithin into spinal cord white matter increased axon sparing, accelerated myelin debris clearance, enhanced Schwann cell infiltration into demyelinated lesions, and increased the number of remyelinated axons. In vitro assays confirmed that direct stimulation of macrophages by E6020 stimulates myelin phagocytosis. These data implicate TLR4 signaling in promoting repair after CNS demyelination, likely by stimulating phagocytic activity of macrophages, sparing axons, recruiting myelinating cells, and promoting remyelination. This work furthers our understanding of immune-myelin interactions and identifies a novel synthetic TLR4 agonist as a potential therapeutic avenue for white matter demyelinating conditions such as spinal cord injury and multiple sclerosis.
Collapse
Affiliation(s)
- Jamie S Church
- Neuroscience Graduate Program, The Ohio State University, Columbus, Ohio, USA.,Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA
| | - Lindsay M Milich
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Jessica K Lerch
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Phillip G Popovich
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Dana M McTigue
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| |
Collapse
|
46
|
Takizawa T, Shibata M, Kayama Y, Shimizu T, Toriumi H, Ebine T, Unekawa M, Koh A, Yoshimura A, Suzuki N. High-mobility group box 1 is an important mediator of microglial activation induced by cortical spreading depression. J Cereb Blood Flow Metab 2017; 37:890-901. [PMID: 27142867 PMCID: PMC5363469 DOI: 10.1177/0271678x16647398] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Single episodes of cortical spreading depression (CSD) are believed to cause typical migraine aura, whereas clusters of spreading depolarizations have been observed in cerebral ischemia and subarachnoid hemorrhage. We recently demonstrated that the release of high-mobility group box 1 (HMGB1) from cortical neurons after CSD in a rodent model is dependent on the number of CSD episodes, such that only multiple CSD episodes can induce significant HMGB1 release. Here, we report that only multiple CSD inductions caused microglial hypertrophy (activation) accompanied by a greater impact on the transcription activity of the HMGB1 receptor genes, TLR2 and TLR4, while the total number of cortical microglia was not affected. Both an HMGB1-neurtalizing antibody and the HMGB1 inhibitor glycyrrhizin abrogated multiple CSD-induced microglial hypertrophy. Moreover, multiple CSD inductions failed to induce microglial hypertrophy in TLR2/4 double knockout mice. These results strongly implicate the HMGB1-TLR2/4 axis in the activation of microglia following multiple CSD inductions. Increased expression of the lysosomal acid hydrolase cathepsin D was detected in activated microglia by immunostaining, suggesting that lysosomal phagocytic activity may be enhanced in multiple CSD-activated microglia.
Collapse
Affiliation(s)
- Tsubasa Takizawa
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Mamoru Shibata
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Yohei Kayama
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Toshihiko Shimizu
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Haruki Toriumi
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Taeko Ebine
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Miyuki Unekawa
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Anri Koh
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Akihiko Yoshimura
- 2 Department of Microbiology and Immunology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Norihiro Suzuki
- 1 Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| |
Collapse
|
47
|
Sadaoka T, Depledge DP, Rajbhandari L, Venkatesan A, Breuer J, Cohen JI. In vitro system using human neurons demonstrates that varicella-zoster vaccine virus is impaired for reactivation, but not latency. Proc Natl Acad Sci U S A 2016; 113:E2403-12. [PMID: 27078099 PMCID: PMC4855584 DOI: 10.1073/pnas.1522575113] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Varicella-zoster virus (VZV) establishes latency in human sensory and cranial nerve ganglia during primary infection (varicella), and the virus can reactivate and cause zoster after primary infection. The mechanism of how the virus establishes and maintains latency and how it reactivates is poorly understood, largely due to the lack of robust models. We found that axonal infection of neurons derived from hESCs in a microfluidic device with cell-free parental Oka (POka) VZV resulted in latent infection with inability to detect several viral mRNAs by reverse transcriptase-quantitative PCR, no production of infectious virus, and maintenance of the viral DNA genome in endless configuration, consistent with an episome configuration. With deep sequencing, however, multiple viral mRNAs were detected. Treatment of the latently infected neurons with Ab to NGF resulted in production of infectious virus in about 25% of the latently infected cultures. Axonal infection of neurons with vaccine Oka (VOka) VZV resulted in a latent infection similar to infection with POka; however, in contrast to POka, VOka-infected neurons were markedly impaired for reactivation after treatment with Ab to NGF. In addition, viral transcription was markedly reduced in neurons latently infected with VOka compared with POka. Our in vitro system recapitulates both VZV latency and reactivation in vivo and may be used to study viral vaccines for their ability to establish latency and reactivate.
Collapse
Affiliation(s)
- Tomohiko Sadaoka
- Medical Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Daniel P Depledge
- Division of Infection and Immunity, MRC Centre for Medical Molecular Virology, University College London, London WC1E 6BT, United Kingdom
| | - Labchan Rajbhandari
- Division of Neuroimmunology and Neuroinfectious Diseases, Department of Neurology, Johns Hopkins University School of Medicine, Johns Hopkins Hospital, Baltimore, MD 21287
| | - Arun Venkatesan
- Division of Neuroimmunology and Neuroinfectious Diseases, Department of Neurology, Johns Hopkins University School of Medicine, Johns Hopkins Hospital, Baltimore, MD 21287
| | - Judith Breuer
- Division of Infection and Immunity, MRC Centre for Medical Molecular Virology, University College London, London WC1E 6BT, United Kingdom
| | - Jeffrey I Cohen
- Medical Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
| |
Collapse
|
48
|
Immune Surveillance of the CNS following Infection and Injury. Trends Immunol 2016; 36:637-650. [PMID: 26431941 DOI: 10.1016/j.it.2015.08.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/10/2015] [Accepted: 08/10/2015] [Indexed: 12/24/2022]
Abstract
The central nervous system (CNS) contains a sophisticated neural network that must be constantly surveyed in order to detect and mitigate a diverse array of challenges. The innate and adaptive immune systems actively participate in this surveillance, which is critical for the maintenance of CNS homeostasis and can facilitate the resolution of infections, degeneration, and tissue damage. Infections and sterile injuries represent two common challenges imposed on the CNS that require a prompt immune response. While the inducers of these two challenges differ in origin, the resultant responses orchestrated by the CNS share some overlapping features. Here, we review how the CNS immunologically discriminates between pathogens and sterile injuries, mobilizes an immune reaction, and, ultimately, regulates local and peripherally-derived immune cells to provide a supportive milieu for tissue repair.
Collapse
|
49
|
García Bueno B, Caso JR, Madrigal JLM, Leza JC. Innate immune receptor Toll-like receptor 4 signalling in neuropsychiatric diseases. Neurosci Biobehav Rev 2016; 64:134-47. [PMID: 26905767 DOI: 10.1016/j.neubiorev.2016.02.013] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/27/2015] [Accepted: 02/12/2016] [Indexed: 02/08/2023]
Abstract
The innate immunity is a stereotyped first line of defense against pathogens and unspecified damage signals. One of main actors of innate immunity are the Toll-like receptors (TLRs), and one of the better characterized members of this family is TLR-4, that it is mainly activated by Gram-negative bacteria lipopolysaccharide. In brain, TLR-4 organizes innate immune responses against infections or cellular damage, but also possesses other physiological functions. In the last years, some evidences suggest a role of TLR-4 in stress and stress-related neuropsychiatric diseases. Peripheral and brain TLR-4 activation triggers sickness behavior, and its expression is a risk factor of depression. Some elements of the TLR-4 signaling pathway are up-regulated in peripheral samples and brain post-mortem tissue from depressed and suicidal patients. The "leaky gut" hypothesis of neuropsychiatric diseases is based on the existence of an increase of the intestinal permeability which results in bacterial translocation able to activate TLR-4. Enhanced peripheral TLR-4 expression/activity has been described in subjects diagnosed with schizophrenia, bipolar disorder and in autistic children. A role for TLR-4 in drugs abuse has been also proposed. The therapeutic potential of pharmacological/genetic modulation of TLRs signaling pathways in neuropsychiatry is promising, but a great preclinical/clinical scientific effort is still needed.
Collapse
Affiliation(s)
- B García Bueno
- Department of Pharmacology, School of Medicine, Complutense University, CIBERSAM, Instituto de Investigación Hospital 12 de Octubre (Imas12), 28040 Madrid, Spain.
| | - J R Caso
- Department of Pharmacology, School of Medicine, Complutense University, CIBERSAM, Instituto de Investigación Hospital 12 de Octubre (Imas12), 28040 Madrid, Spain.
| | - J L M Madrigal
- Department of Pharmacology, School of Medicine, Complutense University, CIBERSAM, Instituto de Investigación Hospital 12 de Octubre (Imas12), 28040 Madrid, Spain.
| | - J C Leza
- Department of Pharmacology, School of Medicine, Complutense University, CIBERSAM, Instituto de Investigación Hospital 12 de Octubre (Imas12), 28040 Madrid, Spain.
| |
Collapse
|
50
|
Jin X, Yamashita T. Microglia in central nervous system repair after injury. J Biochem 2016; 159:491-6. [PMID: 26861995 DOI: 10.1093/jb/mvw009] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/08/2016] [Indexed: 02/03/2023] Open
Abstract
Accumulating evidence suggests that immune cells perform crucial inflammation-related functions including clearing dead tissue and promoting wound healing. Thus, they provide a conducive environment for better neuronal regeneration and functional recovery after adult mammalian central nervous system (CNS) injury. However, activated immune cells can also induce secondary damage of intact tissue and inhibit post-injury CNS repair. The inflammation response is due to the microglial production of cytokines and chemokines for the recruitment of peripheral immune cell populations, such as monocytes, neutrophils, dendritic cells and T lymphocytes. Interestingly, microglia and T lymphocytes can be detected at the injured site in both the early and later stages after nerve injury, whereas other peripheral immune cells infiltrate the injured parenchyma of the brain and spinal cord only in the early post-injury phase, and subsequently disappear. This suggests that microglia and T cells may play crucial roles in the post-injury functional recovery of the CNS. In this review, we summarize the current studies on microglia that examined neuronal regeneration and the molecular signalling mechanisms in the injured CNS. Better understanding of the effects of microglia on neural regeneration will aid the development of therapy strategies to enhance CNS functional recovery after injury.
Collapse
Affiliation(s)
- Xuemei Jin
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 5 Sanbancho, Chiyoda-ku, Tokyo, Japan
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 5 Sanbancho, Chiyoda-ku, Tokyo, Japan
| |
Collapse
|