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Dorrity TJ, Shin H, Gertie JA, Chung H. The Sixth Sense: Self-nucleic acid sensing in the brain. Adv Immunol 2024; 161:53-83. [PMID: 38763702 PMCID: PMC11186578 DOI: 10.1016/bs.ai.2024.03.001] [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] [Indexed: 05/21/2024]
Abstract
Our innate immune system uses pattern recognition receptors (PRRs) as a first line of defense to detect microbial ligands and initiate an immune response. Viral nucleic acids are key ligands for the activation of many PRRs and the induction of downstream inflammatory and antiviral effects. Initially it was thought that endogenous (self) nucleic acids rarely activated these PRRs, however emerging evidence indicates that endogenous nucleic acids are able to activate host PRRs in homeostasis and disease. In fact, many regulatory mechanisms are in place to finely control and regulate sensing of self-nucleic acids by PRRs. Sensing of self-nucleic acids is particularly important in the brain, as perturbations to nucleic acid sensing commonly leads to neuropathology. This review will highlight the role of nucleic acid sensors in the brain, both in disease and homeostasis. We also indicate the source of endogenous stimulatory nucleic acids where known and summarize future directions for the study of this growing field.
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Key Words
- Brain
- DNA sensing PRRs: cGAS, AIM2, TLR9
- Neurodegeneration: Aicardi-Goutieres syndrome (AGS), Alzheimer's disease, Amyotrophic lateral sclerosis, Stroke, Traumatic brain injury
- Neurodevelopment
- Neuroinflammation
- Nuecleic acid immunity
- Pattern recognition receptors (PRRs)
- RNA sensing PRRs: MDA5, RIG-I, PKR, TLR3, TLR7/8
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Affiliation(s)
- Tyler J Dorrity
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States
| | - Heegwon Shin
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States
| | - Jake A Gertie
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States; Medical Scientist Training Program, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States
| | - Hachung Chung
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States.
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2
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Cui Sun M, Otálora-Alcaraz A, Prenderville JA, Downer EJ. Toll-like receptor signalling as a cannabinoid target. Biochem Pharmacol 2024; 222:116082. [PMID: 38438052 DOI: 10.1016/j.bcp.2024.116082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/01/2024] [Accepted: 02/22/2024] [Indexed: 03/06/2024]
Abstract
Toll-like receptors (TLRs) have become a focus in biomedicine and biomedical research given the roles of this unique family of innate immune proteins in immune activation, infection, and autoimmunity. It is evident that TLR dysregulation, and subsequent alterations in TLR-mediated inflammatory signalling, can contribute to disease pathogenesis, and TLR targeted therapies are in development. This review highlights evidence that cannabinoids are key regulators of TLR signalling. Cannabinoids include component of the plant Cannabis sativa L. (C. sativa), synthetic and endogenous ligands, and overall represent a class of compounds whose therapeutic potential and mechanism of action continues to be elucidated. Cannabinoid-based medicines are in the clinic, and are furthermore under intense investigation for broad clinical development to manage symptoms of a range of disorders. In this review, we present an overview of research evidence that signalling linked to a range of TLRs is targeted by cannabinoids, and such cannabinoid mediated effects represent therapeutic avenues for further investigation. First, we provide an overview of TLRs, adaptors and key signalling events, alongside a summary of evidence that TLRs are linked to disease pathologies. Next, we discuss the cannabinoids system and the development of cannabinoid-based therapeutics. Finally, for the bulk of this review, we systematically outline the evidence that cannabinoids (plant-derived cannabinoids, synthetic cannabinoids, and endogenous cannabinoid ligands) can cross-talk with innate immune signalling governed by TLRs, focusing specifically on each member of the TLR family. Cannabinoids should be considered as key regulators of signalling controlled by TLRs, and such regulation should be a major focus in terms of the anti-inflammatory propensity of the cannabinoid system.
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Affiliation(s)
- Melody Cui Sun
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Almudena Otálora-Alcaraz
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Jack A Prenderville
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland; Transpharmation Ireland Limited, Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| | - Eric J Downer
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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3
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Sarkar SK, Willson AML, Jordan MA. The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis. J Immunol Res 2024; 2024:5383099. [PMID: 38213874 PMCID: PMC10783990 DOI: 10.1155/2024/5383099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 01/13/2024] Open
Abstract
Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by the destruction of the myelin sheath of the neuronal axon in the central nervous system. Many risk factors, including environmental, epigenetic, genetic, and lifestyle factors, are responsible for the development of MS. It has long been thought that only adaptive immune cells, especially autoreactive T cells, are responsible for the pathophysiology; however, recent evidence has indicated that innate immune cells are also highly involved in disease initiation and progression. Here, we compile the available data regarding the role immune cells play in MS, drawn from both human and animal research. While T and B lymphocytes, chiefly enhance MS pathology, regulatory T cells (Tregs) may serve a more protective role, as can B cells, depending on context and location. Cells chiefly involved in innate immunity, including macrophages, microglia, astrocytes, dendritic cells, natural killer (NK) cells, eosinophils, and mast cells, play varied roles. In addition, there is evidence regarding the involvement of innate-like immune cells, such as γδ T cells, NKT cells, MAIT cells, and innate-like B cells as crucial contributors to MS pathophysiology. It is unclear which of these cell subsets are involved in the onset or progression of disease or in protective mechanisms due to their plastic nature, which can change their properties and functions depending on microenvironmental exposure and the response of neural networks in damage control. This highlights the need for a multipronged approach, combining stringently designed clinical data with carefully controlled in vitro and in vivo research findings, to identify the underlying mechanisms so that more effective therapeutics can be developed.
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Affiliation(s)
- Sujan Kumar Sarkar
- Department of Anatomy, Histology and Physiology, Faculty of Animal Science and Veterinary Medicine, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh
| | - Annie M. L. Willson
- Biomedical Sciences and Molecular Biology, CPHMVS, James Cook University, Townsville, Queensland 4811, Australia
| | - Margaret A. Jordan
- Biomedical Sciences and Molecular Biology, CPHMVS, James Cook University, Townsville, Queensland 4811, Australia
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4
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Suvieri C, Volpi C. Analysis of Differential TLR Activation in a Mouse Model of Multiple Sclerosis. Methods Mol Biol 2023; 2700:229-247. [PMID: 37603185 DOI: 10.1007/978-1-0716-3366-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Multiple sclerosis (MS) is a neurodegenerative and autoimmune disease affecting the central nervous system (CNS). The precise etiology of MS is still undeciphered, and signs and symptoms of the disease are varied and complex, ranging from axonal degeneration, synaptic, and neuronal loss to demyelination. Inflammation plays a critical role in determining the onset and the progression of MS, but there is still a lot of information missing before scientists come to understand what are the factors that contribute to the establishment of the neuroinflammation. Thus, various murine models, each representative of a specific hallmark of MS, are used to study the processes underlying the pathogenetic mechanisms of the disease in an attempt to find effective drugs for its treatment. Among the many causes of MS, viral infections appear to be one of the most prominent ones. In this scenario, the comprehension of the role of receptors activated upon the recognition of viral, and in general microbial, components in determining onset and progression of the neuroinflammation is of paramount importance. Toll-like receptors (TLRs) are evolutionarily conserved receptors that recognize several pathogen-associated molecular patterns (PAMPs), common structures of the pathogens, or the damage caused by the pathogens within the host. TLRs are thus directly involved in the regulation of inflammatory reactions and in the activation of the innate and, subsequently, the adaptive immune responses crucial for the elimination of infectious pathogens. The role of TLR activation in the development of MS is widely studied in various murine models of MS, as well as in MS patients. In this chapter, we will summarize the current knowledge about the contribution of TLRs to the development or progression of MS, and we will illustrate different methods commonly used for the investigation of the role of different TLRs in various murine models of the disease.
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Affiliation(s)
- Chiara Suvieri
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Claudia Volpi
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy.
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5
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Zhang L, Yang G, Zhang Q, Feng P, Gao M, Yang L. Early pregnancy affects expression of Toll-like receptor signaling members in ovine spleen. Anim Reprod 2021; 18:e20210009. [PMID: 34394755 PMCID: PMC8356075 DOI: 10.1590/1984-3143-ar2021-0009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/30/2021] [Indexed: 11/23/2022] Open
Abstract
Toll-like receptors (TLRs) are involved to the maternal immune tolerance. The spleen is essential for adaptive immune reactions. However, it is unclear that early pregnancy regulates TLR-mediated signalings in the maternal spleen. The purpose of this study was to investigate the effects of early pregnancy on expression of TLR signaling members in the ovine spleen. Ovine spleens were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group). Real-time quantitative PCR, western blot and immunohistochemistry analysis were used to detect TLR signaling members, including TLR2, TLR3, TLR4, TLR5, TLR7, TLR9, myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6) and interleukin-1-receptor-associated kinase 1 (IRAK1). The results showed that expression levels of TLR2, TLR4 and IRAK1 were downregulated, but expression levels of TLR3, TLR5, TLR7, TLR9, TRAF6 and MyD88 were increased during early pregnancy. In addition, MyD88 protein was located in the capsule, trabeculae and splenic cords of the maternal spleen. This paper reports for the first time that early pregnancy has effects on TLR signaling pathways in the ovine spleen, which is beneficial for understanding the maternal immune tolerance during early pregnancy.
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Affiliation(s)
- Leying Zhang
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Gengxin Yang
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Qiongao Zhang
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Pengfei Feng
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Meihong Gao
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
| | - Ling Yang
- Department of Animal Science, School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
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6
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Dieu RS, Wais V, Sørensen MZ, Marczynska J, Dubik M, Kavan S, Thomassen M, Burton M, Kruse T, Khorooshi R, Owens T. Central Nervous System-Endogenous TLR7 and TLR9 Induce Different Immune Responses and Effects on Experimental Autoimmune Encephalomyelitis. Front Neurosci 2021; 15:685645. [PMID: 34211367 PMCID: PMC8241214 DOI: 10.3389/fnins.2021.685645] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
Innate receptors, including Toll like receptors (TLRs), are implicated in pathogenesis of CNS inflammatory diseases such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). TLR response to pathogens or endogenous signals includes production of immunoregulatory mediators. One of these, interferon (IFN)β, a Type I IFN, plays a protective role in MS and EAE. We have previously shown that intrathecal administration of selected TLR ligands induced IFNβ and infiltration of blood-derived myeloid cells into the central nervous system (CNS), and suppressed EAE in mice. We have now extended these studies to evaluate a potential therapeutic role for CNS-endogenous TLR7 and TLR9. Intrathecal application of Imiquimod (TLR7 ligand) or CpG oligonucleotide (TLR9 ligand) into CNS of otherwise unmanipulated mice induced IFNβ expression, with greater magnitude in response to CpG. CD45+ cells in the meninges were identified as source of IFNβ. Intrathecal CpG induced infiltration of monocytes, neutrophils, CD4+ T cells and NK cells whereas Imiquimod did not recruit blood-derived CD45+ cells. CpG, but not Imiquimod, had a beneficial effect on EAE, when given at time of disease onset. This therapeutic effect of CpG on EAE was not seen in mice lacking the Type I IFN receptor. In mice with EAE treated with CpG, the proportion of monocytes was significantly increased in the CNS. Infiltrating cells were predominantly localized to spinal cord meninges and demyelination was significantly reduced compared to non-treated mice with EAE. Our findings show that TLR7 and TLR9 signaling induce distinct inflammatory responses in the CNS with different outcome in EAE and point to recruitment of blood-derived cells and IFNβ induction as possible mechanistic links between TLR9 stimulation and amelioration of EAE. The protective role of TLR9 signaling in the CNS may have application in treatment of diseases such as MS.
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Affiliation(s)
- Ruthe Storgaard Dieu
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Vian Wais
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Michael Zaucha Sørensen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Joanna Marczynska
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Magdalena Dubik
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Stephanie Kavan
- Department of Clinical Genetics, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mark Burton
- Department of Clinical Genetics, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Torben Kruse
- Department of Clinical Genetics, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Reza Khorooshi
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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7
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Mousavi MJ, Mahmoudi M, Ghotloo S. Escape from X chromosome inactivation and female bias of autoimmune diseases. Mol Med 2020; 26:127. [PMID: 33297945 PMCID: PMC7727198 DOI: 10.1186/s10020-020-00256-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Generally, autoimmune diseases are more prevalent in females than males. Various predisposing factors, including female sex hormones, X chromosome genes, and the microbiome have been implicated in the female bias of autoimmune diseases. During embryogenesis, one of the X chromosomes in the females is transcriptionally inactivated, in a process called X chromosome inactivation (XCI). This equalizes the impact of two X chromosomes in the females. However, some genes escape from XCI, providing a basis for the dual expression dosage of the given gene in the females. In the present review, the contribution of the escape genes to the female bias of autoimmune diseases will be discussed.
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Affiliation(s)
- Mohammad Javad Mousavi
- Department of Hematology, Faculty of Allied Medicine, Bushehr University of Medical Sciences, Bushehr, Iran.,Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mahdi Mahmoudi
- Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Somayeh Ghotloo
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Kashan University of Medical Sciences, Kashan, Iran.
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8
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Bu-Shen-Yi-Sui Capsule, an Herbal Medicine Formula, Promotes Remyelination by Modulating the Molecular Signals via Exosomes in Mice with Experimental Autoimmune Encephalomyelitis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7895293. [PMID: 32774683 PMCID: PMC7396036 DOI: 10.1155/2020/7895293] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/12/2020] [Accepted: 06/26/2020] [Indexed: 12/21/2022]
Abstract
Multiple sclerosis (MS) is a common inflammatory demyelinating disorder of the central nervous system. Bu-shen-yi-sui capsule (BSYSC) could significantly reduce the relapse rate, prevent the progression of MS, and enhance remyelination following neurological injury in experimental autoimmune encephalomyelitis (EAE), an established model of MS; however, the mechanism underlying the effect of BSYSC on remyelination has not been well elucidated. This study showed that exosomes carrying biological information are involved in the pathological process of MS and that modified exosomes can promote remyelination by modulating related proteins and microRNAs (miRs). Here, the mechanism by which BSYSC promoted remyelination via exosome-mediated molecular signals was investigated in EAE mice and oligodendrocyte progenitor cells (OPCs) in vitro. The results showed that BSYSC treatment significantly improved the body weight and clinical scores of EAE mice, alleviated inflammatory infiltration and nerve fiber injury, protected the ultrastructural integrity of the myelin sheath, and significantly increased the expression of myelin basic protein (MBP) in EAE mice. In an in vitro OPC study, BSYSC-containing serum, especially 20% BSYSC, promoted the proliferation and migration of OPCs and induced OPCs to differentiate into mature oligodendrocytes that expressed MBP. Furthermore, BSYSC treatment regulated the expression of neuropilin- (NRP-) 1 and GTX, downregulated the expression of miR-16, let-7, miR-15, miR-98, miR-486, and miR-182, and upregulated the level of miR-146 in serum exosomes of EAE mice. In conclusion, these results suggested that BSYSC has a neuroprotective effect and facilitates remyelination and that the mechanism underlying the effect of BSYSC on remyelination probably involves regulation of the NRP-1 and GTX proteins and miRs in serum exosomes, which drive promyelination.
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9
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Deerhake ME, Biswas DD, Barclay WE, Shinohara ML. Pattern Recognition Receptors in Multiple Sclerosis and Its Animal Models. Front Immunol 2019; 10:2644. [PMID: 31781124 PMCID: PMC6861384 DOI: 10.3389/fimmu.2019.02644] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
Pattern recognition receptors (PRRs) coordinate the innate immune response and have a significant role in the development of multiple sclerosis (MS). Accumulating evidence has identified both pathogenic and protective functions of PRR signaling in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). Additionally, evidence for PRR signaling in non-immune cells and PRR responses to host-derived endogenous ligands has also revealed new pathways controlling the development of CNS autoimmunity. Many PRRs remain uncharacterized in MS and EAE, and understanding the distinct triggers and functions of PRR signaling in CNS autoimmunity requires further investigation. In this brief review, we discuss the diverse pathogenic and protective functions of PRRs in MS and EAE, and highlight major avenues for future research.
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Affiliation(s)
- M Elizabeth Deerhake
- Department of Immunology, Duke University School of Medicine, Durham, NC, United States
| | - Debolina D Biswas
- Department of Immunology, Duke University School of Medicine, Durham, NC, United States
| | - William E Barclay
- Department of Immunology, Duke University School of Medicine, Durham, NC, United States
| | - Mari L Shinohara
- Department of Immunology, Duke University School of Medicine, Durham, NC, United States.,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, United States
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10
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Kim T, Valera E, Desplats P. Alterations in Striatal microRNA-mRNA Networks Contribute to Neuroinflammation in Multiple System Atrophy. Mol Neurobiol 2019; 56:7003-7021. [PMID: 30968343 DOI: 10.1007/s12035-019-1577-3] [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: 01/09/2019] [Accepted: 03/20/2019] [Indexed: 10/27/2022]
Abstract
Multiple systems atrophy (MSA) is a rare neurodegenerative disorder characterized by the accumulation of α-synuclein in glial cells and neurodegeneration in the striatum, substantia nigra, and cerebellum. Aberrant miRNA regulation has been associated with neurodegeneration, including alterations of specific miRNAs in brain tissue, serum, and cerebrospinal fluid from MSA patients. Still, a causal link between deregulation of miRNA networks and pathological changes in the transcriptome remains elusive. We profiled ~ 800 miRNAs in the striatum of MSA patients in comparison to healthy individuals to identify specific miRNAs altered in MSA. In addition, we performed a parallel screening of 700 transcripts associated with neurodegeneration to determine the impact of miRNA deregulation on the transcriptome. We identified 60 miRNAs with abnormal levels in MSA brains that are involved in extracellular matrix receptor interactions, prion disease, inflammation, ubiquitin-mediated proteolysis, and addiction pathways. Using the correlation between miRNA expression and the abundance of their known targets, miR-124-3p, miR-19a-3p, miR-27b-3p, and miR-29c-3p were identified as key regulators altered in MSA, mainly contributing to neuroinflammation. Finally, our study also uncovered a potential link between Alzheimer's disease (AD) and MSA pathologies that involves miRNAs and deregulation of BACE1. Our results provide a comprehensive appraisal of miRNA alterations in MSA and their effect on the striatal transcriptome, supporting that aberrant miRNA expression is highly correlated with changes in gene transcription associated with MSA neuropathology, in particular those driving inflammation, disrupting myelination, and potentially impacting α-synuclein accumulation via deregulation of autophagy and prion mechanisms.
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Affiliation(s)
- Taeyeon Kim
- Department of Neuroscience, University of California San Diego, 9500 Gilman Dr., MTF 344 MC0624, La Jolla, CA, 92093-0624, USA
| | - Elvira Valera
- Department of Neuroscience, University of California San Diego, 9500 Gilman Dr., MTF 344 MC0624, La Jolla, CA, 92093-0624, USA
| | - Paula Desplats
- Department of Neuroscience, University of California San Diego, 9500 Gilman Dr., MTF 344 MC0624, La Jolla, CA, 92093-0624, USA. .,Department of Pathology, University of California San Diego, 9500 Gilman Dr., MTF 344 MC0624, La Jolla, CA, 92093-0624, USA.
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11
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Sánchez-Ruiz M, Polakos NK, Blau T, Utermöhlen O, Brunn A, Montesinos-Rongen M, Hünig T, Deckert M. TLR signals license CD8 T cells to destroy oligodendrocytes expressing an antigen shared with a Listeria pathogen. Eur J Immunol 2019; 49:413-427. [PMID: 30666625 DOI: 10.1002/eji.201847834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/22/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022]
Abstract
Increasing evidence suggests a role of CD8 T cells in autoimmune demyelinating CNS disease, which, however, is still controversially discussed. Mice, which express ovalbumin (OVA) as cytosolic self-antigen in oligodendrocytes (ODC-OVA mice), respond to CNS infection induced by OVA-expressing attenuated Listeria with CD8 T cell-mediated inflammatory demyelination. This model is suitable to decipher the contribution of CD8 T cells and the pathogen in autoimmune CNS disease. Here, we show that both antigen and pathogen are required in the CNS for disease induction, though not in a physically linked fashion. Intracerebral challenge with combined toll like receptor (TLR) TLR2 and TLR9 as well as TLR7 and TLR9 agonists substituted for the bacterial stimulus, but not with individual TLR agonists (TLR2, TLR3,TLR5,TLR7, TLR9). Furthermore, MyD88 inactivation rendered ODC-OVA mice resistant to disease induction. Collectively, CD8 T cell-mediated destruction of oligodendrocytes is activated if (i) an antigen shared with an infectious agent is provided in the CNS microenvironment and (ii) innate immune signals inform the CNS microenvironment that pathogen removal warrants an immune attack by CD8 T cells, even at the expense of locally restricted demyelination.
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Affiliation(s)
- Monica Sánchez-Ruiz
- Department of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | | | - Tobias Blau
- Department of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Olaf Utermöhlen
- Institute for Medical Microbiology, Immunology, and Hygiene, Medical Center, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
| | - Anna Brunn
- Department of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Manuel Montesinos-Rongen
- Department of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Hünig
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Martina Deckert
- Department of Neuropathology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
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12
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Cavalcante P, Barzago C, Baggi F, Antozzi C, Maggi L, Mantegazza R, Bernasconi P. Toll-like receptors 7 and 9 in myasthenia gravis thymus: amplifiers of autoimmunity? Ann N Y Acad Sci 2018; 1413:11-24. [PMID: 29363775 DOI: 10.1111/nyas.13534] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022]
Abstract
Pathogen infections and dysregulated Toll-like receptor (TLR)-mediated innate immune responses are suspected to play key roles in autoimmunity. Among TLRs, TLR7 and TLR9 have been implicated in several autoimmune conditions, mainly because of their ability to promote abnormal B cell activation and survival. Recently, we provided evidence of Epstein-Barr virus (EBV) persistence and reactivation in the thymus of myasthenia gravis (MG) patients, suggesting an involvement of EBV in the intrathymic pathogenesis of the disease. Considerable data highlight the existence of pathogenic crosstalk among EBV, TLR7, and TLR9: EBV elicits TLR7/9 signaling, which in turn can enhance B cell dysfunction and autoimmunity. In this article, after a brief summary of data demonstrating TLR activation in MG thymus, we provide an overview on the contribution of TLR7 and TLR9 to autoimmune diseases and discuss our recent findings indicating a pivotal role for these two receptors, along with EBV, in driving, perpetuating, and/or amplifying intrathymic B cell dysregulation and autoimmune responses in MG. Development of therapeutic approaches targeting TLR7 and TLR9 signaling could be a novel strategy for treating the chronic inflammatory autoimmune process in myasthenia gravis.
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Affiliation(s)
- Paola Cavalcante
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Claudia Barzago
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Fulvio Baggi
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Carlo Antozzi
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Lorenzo Maggi
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Renato Mantegazza
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Pia Bernasconi
- Neurology IV, Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta", Milan, Italy
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Chiurchiù V, Leuti A, Cencioni MT, Albanese M, De Bardi M, Bisogno T, Centonze D, Battistini L, Maccarrone M. Modulation of monocytes by bioactive lipid anandamide in multiple sclerosis involves distinct Toll-like receptors. Pharmacol Res 2016; 113:313-319. [DOI: 10.1016/j.phrs.2016.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 09/02/2016] [Accepted: 09/06/2016] [Indexed: 01/01/2023]
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Xiao Q, Li X, Sun D, Yi H, Lu X, Nian H. TLR7 Engagement on Dendritic Cells Enhances Autoreactive Th17 Responses via Activation of ERK. THE JOURNAL OF IMMUNOLOGY 2016; 197:3820-3830. [DOI: 10.4049/jimmunol.1600333] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 09/12/2016] [Indexed: 11/19/2022]
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Clec4A4 is a regulatory receptor for dendritic cells that impairs inflammation and T-cell immunity. Nat Commun 2016; 7:11273. [PMID: 27068492 PMCID: PMC4832068 DOI: 10.1038/ncomms11273] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/08/2016] [Indexed: 01/13/2023] Open
Abstract
Dendritic cells (DCs) comprise several subsets that are critically involved in the initiation and regulation of immunity. Clec4A4/DC immunoreceptor 2 (DCIR2) is a C-type lectin receptor (CLR) exclusively expressed on CD8α− conventional DCs (cDCs). However, how Clec4A4 controls immune responses through regulation of the function of CD8α− cDCs remains unclear. Here we show that Clec4A4 is a regulatory receptor for the activation of CD8α− cDCs that impairs inflammation and T-cell immunity. Clec4a4−/−CD8α− cDCs show enhanced cytokine production and T-cell priming following Toll-like receptor (TLR)-mediated activation. Furthermore, Clec4a4−/− mice exhibit TLR-mediated hyperinflammation. On antigenic immunization, Clec4a4−/− mice show not only augmented T-cell responses but also progressive autoimmune pathogenesis. Conversely, Clec4a4−/− mice exhibit resistance to microbial infection, accompanied by enhanced T-cell responses against microbes. Thus, our findings highlight roles of Clec4A4 in regulation of the function of CD8α− cDCs for control of the magnitude and quality of immune response. Clec4A4 is a C-type lectin receptor highly expressed by CD8α− dendritic cells. Here the authors show that its loss of function results in enhanced T cell responses and exacerbated autoimmunity, implicating Clec4A4 in limiting activation of the CD8α− dendritic cells.
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Dysregulation of Toll-Like Receptor 7 Compromises Innate and Adaptive T Cell Responses and Host Resistance to an Attenuated West Nile Virus Infection in Old Mice. J Virol 2015; 90:1333-44. [PMID: 26581984 DOI: 10.1128/jvi.02488-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/06/2015] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), a mosquito-borne flavivirus, has induced severe neurological symptoms, mostly in the elderly population. No vaccines are available for human use. Recent work showed that an attenuated WNV, a nonstructural (NS) 4B-P38G mutant, induced no lethality but strong immune responses in young (6- to 10-week-old) mice. While studying protective efficacy, we found unexpectedly that old (21- to 22-month) mice were susceptible to WNV NS4B-P38G mutant infection but were protected from subsequent lethal wild-type WNV challenge. Compared to responses in young mice, the NS4B-P38G mutant triggered higher inflammatory cytokine and interleukin-10 (IL-10) production, a delayed γδ T cell expansion, and lower antibody and WNV-specific T cell responses in old mice. Toll-like receptor 7 (TLR7) is expressed on multiple types of cells. Impaired TLR7 signaling in old mice led to dendritic cell (DC) antigen-presenting function compromise and a reduced γδ T cell and regulatory T cell (Treg) expansion during NS4B-P38G mutant infection. R848, a TLR7 agonist, decreased host vulnerability in NS4B-P38G-infected old mice by enhancing γδ T cell and Treg expansion and the antigen-presenting capacity of DCs, thereby promoting T cell responses. In summary, our results suggest that dysregulation of TLR7 partially contributes to impaired innate and adaptive T cell responses and an enhanced vulnerability in old mice during WNV NS4B-P38G mutant infection. R848 increases the safety and efficacy during immunization of old mice with the WNV NS4B-P38G mutant. IMPORTANCE The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), an emerging mosquito-borne flavivirus, has induced severe neurological symptoms more frequently in the elderly population. No vaccines are available for human use. Here, we used an aged mouse model to investigate the protective efficacy of an attenuated WNV, the nonstructural 4B-P38G mutant, which was previously shown to induce no lethality but strong immune responses in young adult mice. Studies that contribute to a mechanistic understanding of immune defects in the elderly will allow the development of strategies to improve responses to infectious diseases and to increase vaccine efficacy and safety in aging individuals.
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Tran NL, Manzin-Lorenzi C, Santiago-Raber ML. Toll-like receptor 8 deletion accelerates autoimmunity in a mouse model of lupus through a Toll-like receptor 7-dependent mechanism. Immunology 2015; 145:60-70. [PMID: 25424423 DOI: 10.1111/imm.12426] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/13/2014] [Accepted: 11/21/2014] [Indexed: 12/22/2022] Open
Abstract
Systemic lupus erythematosus is an autoimmune disorder characterized by increased levels of lymphocyte activation, antigen presentation by dendritic cells, and the formation of autoantibodies. This leads to immune complex-mediated glomerulonephritis. Toll-like receptor 7 (T7) and TLR9 localize to the endosomal compartment and play important roles in the generation of autoantibodies against nuclear components, as they recognize RNA and DNA, respectively. In contrast, very little is known about endogenous TLR8 activation in mice. We therefore tested whether TLR8 could affect autoimmune responses in a murine model of lupus. We introduced a Tlr8 null mutation into C57BL/6 mice congenic for the Nba2 (NZB autoimmunity 2) locus and bearing the Yaa (Y-linked autoimmune acceleration) mutation containing a tlr8 duplicated gene, and monitored disease development, autoantibody production, and glomerulonephritis-associated mortality. Cellular responses were investigated in female Nba2.TLR8(-/-) mice bearing no copy of tlr8. The TLR8 deficiency accelerated disease progression and mortality, increased the number of circulating antibodies and activated monocytes, and heightened cellular responses to TLR7 ligation. TLR8-deficient antigen-presenting cells exhibited increased levels of MHC class II expression. The ability of dendritic cells to present antigens to allogeneic T cells after TLR7 ligation was also improved by TLR8 deficiency. TLR8 deletion accelerated autoimmunity in lupus-prone mice in response to TLR7 activation. Antigen-presenting cell function seemed to play a key role in mediating the effects of TLR8 deficiency.
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Affiliation(s)
- Ngoc Lan Tran
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Ivanova MV, Tukhvatulin AI, Dzharullaeva AS, Logunov DY, Zakharova MN. Myelin lipids in the development of the autoimmune response in multiple sclerosis. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414040035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Plasmocytoid dendritic cell deficit of early response to toll-like receptor 7 agonist stimulation in multiple sclerosis patients. Clin Immunol 2014; 153:211-9. [DOI: 10.1016/j.clim.2014.04.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 04/11/2014] [Accepted: 04/30/2014] [Indexed: 12/25/2022]
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