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Karati D, Mukherjee S, Roy S. A Promising Drug Candidate as Potent Therapeutic Approach for Neuroinflammation and Its In Silico Justification of Chalcone Congeners: a Comprehensive Review. Mol Neurobiol 2024; 61:1873-1891. [PMID: 37801205 DOI: 10.1007/s12035-023-03632-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023]
Abstract
Multiple genetic, environmental, and immunological variables cause neuropsychiatric disorders (NPDs). The induced inflammatory immune response is also connected to the severity and treatment outcomes of various NPDs. These reactions also significantly impact numerous brain functions such as GABAergic signaling and neurotransmitter synthesis through inflammatory cytokines and chemokines. Chalcones (1,3-diaryl-2-propen-1-ones) and their heterocyclic counterparts are flavonoids with various biological characteristics including anti-inflammatory activity. Several pure chalcones have been clinically authorized or studied in humans. Chalcones are favored for their diagnostic and therapeutic efficacy in neuroinflammation due to their tiny molecular size, easy manufacturing, and flexibility for changes to adjust lipophilicity ideal for BBB penetrability. These compounds reached an acceptable plasma concentration and were well-tolerated in clinical testing. As a result, they are attracting increasing attention from scientists. However, chalcones' therapeutic potential remains largely untapped. This paper is aimed at highlighting the causes of neuroinflammation, more potent chalcone congeners, their mechanisms of action, and relevant structure-activity relationships.
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Affiliation(s)
- Dipanjan Karati
- Department of Pharmaceutical Technology, School of Pharmacy, Techno India University, Kolkata, West Bengal, 700091, India
| | - Swarupananda Mukherjee
- Department of Pharmaceutical Technology, NSHM Knowledge Campus, Kolkata, 124 B.L. Saha Road, Kolkata, West Bengal, 700053, India
| | - Souvik Roy
- Department of Pharmaceutical Technology, NSHM Knowledge Campus, Kolkata, 124 B.L. Saha Road, Kolkata, West Bengal, 700053, India.
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Ma Q, Chen J, Kong X, Zeng Y, Chen Z, Liu H, Liu L, Lu S, Wang X. Interactions between CNS and immune cells in tuberculous meningitis. Front Immunol 2024; 15:1326859. [PMID: 38361935 PMCID: PMC10867975 DOI: 10.3389/fimmu.2024.1326859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024] Open
Abstract
The central nervous system (CNS) harbors its own special immune system composed of microglia in the parenchyma, CNS-associated macrophages (CAMs), dendritic cells, monocytes, and the barrier systems within the brain. Recently, advances in the immune cells in the CNS provided new insights to understand the development of tuberculous meningitis (TBM), which is the predominant form of Mycobacterium tuberculosis (M.tb) infection in the CNS and accompanied with high mortality and disability. The development of the CNS requires the protection of immune cells, including macrophages and microglia, during embryogenesis to ensure the accurate development of the CNS and immune response following pathogenic invasion. In this review, we summarize the current understanding on the CNS immune cells during the initiation and development of the TBM. We also explore the interactions of immune cells with the CNS in TBM. In the future, the combination of modern techniques should be applied to explore the role of immune cells of CNS in TBM.
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Affiliation(s)
| | | | | | | | | | | | | | - Shuihua Lu
- National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, Guangdong, China
| | - Xiaomin Wang
- National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, Guangdong, China
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3
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Antelo G, Comas S, Casas F, Valduvieco I, Barreto T, Laplana M, Mases J, Oses G, Mollà M. Clinical outcomes and timing on the combination of focal radiation therapy and immunotherapy for the treatment of brain metastases. Front Immunol 2023; 14:1236398. [PMID: 37915576 PMCID: PMC10616465 DOI: 10.3389/fimmu.2023.1236398] [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: 06/07/2023] [Accepted: 10/05/2023] [Indexed: 11/03/2023] Open
Abstract
Introduction Radiotherapy is one of the standard treatments for brain metastases (BM). Over the past years, the introduction of immunotherapy as routine treatment for solid tumors has forced investigators to review and evaluate how it would interact with radiation. Radiation and Immunotherapy have shown a synergic effect activating the host's immune system and enhancing treatment response. The combinatory effect on BM is currently under investigation. Methods Data published on Pubmed to determine toxicity, survival, treatment characteristics and timing on the combination of radiotherapy and immunotherapy for the treatment of BM has been reviewed. Results Mostly retrospective reviews report an improvement of intracranial progression free survival (iPFS) when combining radioimmunotherapy for BM patients. Two systematic reviews and meta-analysis and one phase II prospective trial also report a benefit on iPFS without an increase of toxicity. Among the published literature, the definition of concurrency is heterogeneous, being one month or even narrowed intervals correlated to better clinical outcomes. Toxicity due to concurrent radioimmunotherapy, specifically symptomatic radionecrosis, is also directly analyzed and reported to be low, similar to the toxicity rates secondary to stereotactic radiosurgery alone. Conclusion Radiation combined with immunotherapy has shown in predominantly retrospective reviews a synergic effect on the treatment of BM. The concurrent combination of radioimmunotherapy is a feasible therapeutic strategy and seems to improve clinical outcomes, especially iPFS, when delivered within <30 days. Larger prospective and randomized studies are needed to establish reliable outcomes, best delivery strategies and toxicity profile.
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Affiliation(s)
- Gabriela Antelo
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Silvia Comas
- Radiation Oncology Department, Institut Catalá d'Oncologia (ICO), Badalona, Badalona, Spain
| | - Francesc Casas
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Izaskun Valduvieco
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Tanny Barreto
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - María Laplana
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Joel Mases
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Gabriela Oses
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
| | - Meritxell Mollà
- Radiation Oncology Department, Hospital Clinic Barcelona, Barcelona, Spain
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Latham AS, Moreno JA, Geer CE. Biological agents and the aging brain: glial inflammation and neurotoxic signaling. FRONTIERS IN AGING 2023; 4:1244149. [PMID: 37649972 PMCID: PMC10464498 DOI: 10.3389/fragi.2023.1244149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023]
Abstract
Neuroinflammation is a universal characteristic of brain aging and neurological disorders, irrespective of the disease state. Glial inflammation mediates this signaling, through astrocyte and microglial polarization from neuroprotective to neurotoxic phenotypes. Glial reactivity results in the loss of homeostasis, as these cells no longer provide support to neurons, in addition to the production of chronically toxic pro-inflammatory mediators. These glial changes initiate an inflammatory brain state that injures the central nervous system (CNS) over time. As the brain ages, glia are altered, including increased glial cell numbers, morphological changes, and either a pre-disposition or inability to become reactive. These alterations induce age-related neuropathologies, ultimately leading to neuronal degradation and irreversible damage associated with disorders of the aged brain, including Alzheimer's Disease (AD) and other related diseases. While the complex interactions of these glial cells and the brain are well studied, the role additional stressors, such as infectious agents, play on age-related neuropathology has not been fully elucidated. Both biological agents in the periphery, such as bacterial infections, or in the CNS, including viral infections like SARS-CoV-2, push glia into neuroinflammatory phenotypes that can exacerbate pathology within the aging brain. These biological agents release pattern associated molecular patterns (PAMPs) that bind to pattern recognition receptors (PRRs) on glial cells, beginning an inflammatory cascade. In this review, we will summarize the evidence that biological agents induce reactive glia, which worsens age-related neuropathology.
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Affiliation(s)
- Amanda S. Latham
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
- Brain Research Center, Colorado State University, Fort Collins, CO, United States
| | - Julie A. Moreno
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
- Brain Research Center, Colorado State University, Fort Collins, CO, United States
| | - Charlize E. Geer
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
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Wang J, Zhao X, Zhou R, Wang M, Xiang W, You Z, Li M, Tang R, Zheng J, Li J, Zhu L, Gao J, Li H, Pang R, Zhang A. Gut microbiota and transcriptome dynamics in every-other-day fasting are associated with neuroprotection in rats with spinal cord injury. Front Microbiol 2023; 14:1206909. [PMID: 37577426 PMCID: PMC10417830 DOI: 10.3389/fmicb.2023.1206909] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/04/2023] [Indexed: 08/15/2023] Open
Abstract
Introduction Every-other-day fasting (EODF) is a classical intermittent fasting (IF) mode with neuroprotective effects that promotes motor function recovery after spinal cord injury (SCI) in rats. However, its dynamic effects on the gut microbiota and spinal cord transcriptome remain unknown. Methods In this study, 16S rRNA sequencing and RNA-seq analysis were used to investigate the effects of ad libitum (AL) and EODF dietary modes on the structural characteristics of rat gut microbiota in rats and the spinal cord transcriptome at various time points after SCI induction. Results Our results showed that both dietary modes affected the bacterial community composition in SCI rats, with EODF treatment inducing and suppressing dynamic changes in the abundances of potentially anti-inflammatory and pro-inflammatory bacteria. Furthermore, the differentially expressed genes (DEGs) enriched after EODF intervention in SCI rats were associated with various biological events, including immune inflammatory response, cell differentiation, protein modification, neural growth, and apoptosis. In particular, significant spatiotemporal differences were apparent in the DEGs associated with neuroprotection between the EODF and AL interventions. These DGEs were mainly focused on days 1, 3, and 7 after SCI. The relative abundance of certain genera was significantly correlated with DEGs associated with neuroprotective effects in the EODF-SCI group. Discussion Our results showed that EODF treatment may exert neuroprotective effects by modulating the transcriptome expression profile following SCI in rats. Furthermore, gut microbiota may be partially involved in mediating these effects.
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Affiliation(s)
- Junyu Wang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaohua Zhao
- Department of Rehabilitation Medicine, General Hospital of Western Theater Command, Chengdu, China
- Department of Rehabilitation Medicine, The People’s Hospital of Tongliang District, Chongqing, China
| | - Ruihan Zhou
- Department of Rehabilitation Medicine, General Hospital of Western Theater Command, Chengdu, China
| | - Meiyu Wang
- Rehabilitation and Wellness Care Centre, Tian Fu College of Swufe, Chengdu, China
| | - Wu Xiang
- Department of Rehabilitation Medicine, General Hospital of Western Theater Command, Chengdu, China
| | - Zilong You
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Min Li
- Department of Rehabilitation Medicine, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Ruiling Tang
- Department of Rehabilitation Medicine, General Hospital of Western Theater Command, Chengdu, China
| | - Jingqi Zheng
- Department of Rehabilitation Medicine, General Hospital of Western Theater Command, Chengdu, China
| | - Jiayu Li
- School of Health Preservation and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Li Zhu
- Department of Rehabilitation Medicine, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Jiaxin Gao
- Department of Rehabilitation Medicine, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Huaqiang Li
- School of Health Preservation and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Rizhao Pang
- Department of Rehabilitation Medicine, The People’s Hospital of Tongliang District, Chongqing, China
| | - Anren Zhang
- School of Health Preservation and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Van Acker ZP, Perdok A, Hellemans R, North K, Vorsters I, Cappel C, Dehairs J, Swinnen JV, Sannerud R, Bretou M, Damme M, Annaert W. Phospholipase D3 degrades mitochondrial DNA to regulate nucleotide signaling and APP metabolism. Nat Commun 2023; 14:2847. [PMID: 37225734 DOI: 10.1038/s41467-023-38501-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
Phospholipase D3 (PLD3) polymorphisms are linked to late-onset Alzheimer's disease (LOAD). Being a lysosomal 5'-3' exonuclease, its neuronal substrates remained unknown as well as how a defective lysosomal nucleotide catabolism connects to AD-proteinopathy. We identified mitochondrial DNA (mtDNA) as a major physiological substrate and show its manifest build-up in lysosomes of PLD3-defective cells. mtDNA accretion creates a degradative (proteolytic) bottleneck that presents at the ultrastructural level as a marked abundance of multilamellar bodies, often containing mitochondrial remnants, which correlates with increased PINK1-dependent mitophagy. Lysosomal leakage of mtDNA to the cytosol activates cGAS-STING signaling that upregulates autophagy and induces amyloid precursor C-terminal fragment (APP-CTF) and cholesterol accumulation. STING inhibition largely normalizes APP-CTF levels, whereas an APP knockout in PLD3-deficient backgrounds lowers STING activation and normalizes cholesterol biosynthesis. Collectively, we demonstrate molecular cross-talks through feedforward loops between lysosomal nucleotide turnover, cGAS-STING and APP metabolism that, when dysregulated, result in neuronal endolysosomal demise as observed in LOAD.
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Affiliation(s)
- Zoë P Van Acker
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Anika Perdok
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Ruben Hellemans
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Katherine North
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Inge Vorsters
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Cedric Cappel
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Marine Bretou
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Markus Damme
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium.
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium.
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7
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Wei C, Li P, Liu L, Zhang H, Zhao T, Chen Y. Degradable Poly(amino acid) Vesicles Modulate DNA-Induced Inflammation after Traumatic Brain Injury. Biomacromolecules 2023; 24:909-920. [PMID: 36629517 DOI: 10.1021/acs.biomac.2c01334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Following brain trauma, secondary injury from molecular and cellular changes causes progressive cerebral tissue damage. Acute/chronic neuroinflammation following traumatic brain injury (TBI) is a key player in the development of secondary injury. Rapidly elevated cell-free DNAs (cfDNAs) due to cell death could lead to production of inflammatory cytokines that aggravate TBI. Herein, we designed poly(amino acid)-based cationic nanoparticles (cNPs) and applied them intravenously in a TBI mice model with the purpose of scavenging cfDNA in the brain and suppressing the acute inflammation. In turn, these cNPs could effectively eliminate endogenous cfDNA, inhibit excessive activation of inflammation, and promote neural functional recovery.
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Affiliation(s)
- Cong Wei
- School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China
| | - Peipei Li
- School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China
| | - Lixin Liu
- School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China.,State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Guangzhou 510006, Guangdong, China.,Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China
| | - Hong Zhang
- Department of Biomedical Engineering, Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China
| | - Tianyu Zhao
- School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China
| | - Yongming Chen
- School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China.,State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Guangzhou 510006, Guangdong, China.,Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China
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Sušjan-Leite P, Ramuta TŽ, Boršić E, Orehek S, Hafner-Bratkovič I. Supramolecular organizing centers at the interface of inflammation and neurodegeneration. Front Immunol 2022; 13:940969. [PMID: 35979366 PMCID: PMC9377691 DOI: 10.3389/fimmu.2022.940969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022] Open
Abstract
The pathogenesis of neurodegenerative diseases involves the accumulation of misfolded protein aggregates. These deposits are both directly toxic to neurons, invoking loss of cell connectivity and cell death, and recognized by innate sensors that upon activation release neurotoxic cytokines, chemokines, and various reactive species. This neuroinflammation is propagated through signaling cascades where activated sensors/receptors, adaptors, and effectors associate into multiprotein complexes known as supramolecular organizing centers (SMOCs). This review provides a comprehensive overview of the SMOCs, involved in neuroinflammation and neurotoxicity, such as myddosomes, inflammasomes, and necrosomes, their assembly, and evidence for their involvement in common neurodegenerative diseases. We discuss the multifaceted role of neuroinflammation in the progression of neurodegeneration. Recent progress in the understanding of particular SMOC participation in common neurodegenerative diseases such as Alzheimer's disease offers novel therapeutic strategies for currently absent disease-modifying treatments.
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Affiliation(s)
- Petra Sušjan-Leite
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Taja Železnik Ramuta
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Elvira Boršić
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Sara Orehek
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Iva Hafner-Bratkovič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Ljubljana, Slovenia
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Ito S, Nakashima H, Ishikiriyama T, Nakashima M, Yamagata A, Imakiire T, Kinoshita M, Seki S, Kumagai H, Oshima N. Effects of a CCR2 antagonist on macrophages and Toll-like receptor 9 expression in a mouse model of diabetic nephropathy. Am J Physiol Renal Physiol 2021; 321:F757-F770. [PMID: 34719947 DOI: 10.1152/ajprenal.00191.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/19/2021] [Indexed: 12/24/2022] Open
Abstract
The pathogenesis of diabetic nephropathy (DN) is related to macrophage (Mφ) recruitment to the kidneys, tumor necrosis factor-α (TNF-α) production, and oxidative stress. Toll-like receptor 9 (TLR9) activation is reportedly involved in systemic inflammation, and it exacerbates this condition in metabolic syndrome. Therefore, we hypothesized that TLR9 plays a role in the pathogenesis of DN. Two subsets of kidney Mφs in DN model (db/db) mice were analyzed using flow cytometry to evaluate their distribution and TLR9 expression and function. Mice were administered the CCR2 antagonist INCB3344 for 8 wk; changes in Mφ distribution and function and its therapeutic effects on DN pathology were examined. Bone marrow-derived CD11bhigh (BM-Mφ) and tissue-resident CD11blow Mφs (Res-Mφ) were identified in the mouse kidneys. As DN progressed, the BM-Mφ number, TLR9 expression, and TNF-α production increased significantly. In Res-Mφs, reactive oxygen species (ROS) production and phagocytic activity were enhanced. INCB3344 decreased albuminuria, serum creatinine level, BM-Mφ abundance, TLR9 expression, and TNF-α production by BM-Mφs and ROS production by Res-Mφs. Both increased activation of BM-Mφ via TLR9 and TNF-α production and increased ROS production by Res-Mφs were involved in DN progression. Thus, inactivating Mφs and their TLR9 expression by INCB3344 is a potential therapeutic strategy for DN.NEW & NOTEWORTHY We classified kidney macrophages (Mφs) into bone marrow-derived Mφs (BM-Mφs) expressing high CD11b and tissue-specific resident Mφ (Res-Mφs) expressing low CD11b. In diabetic nephropathy (DN) model mice, Toll-like receptor 9 (TLR9) expression and TNF-α production via TLR9 activation in BM-Mφs and ROS production in Res-Mφs were enhanced. Furthermore, CCR2 antagonist suppressed the kidney infiltration of BM-Mφs and their function and the ROS production by Res-Mφs, with concomitant TLR9 suppression. Our study presents a new therapeutic strategy for DN.
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Affiliation(s)
- Seigo Ito
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Hiroyuki Nakashima
- Department of Immunology and Microbiology, National Defense Medical College, Tokorozawa, Japan
| | - Takuya Ishikiriyama
- Department of Immunology and Microbiology, National Defense Medical College, Tokorozawa, Japan
| | - Masahiro Nakashima
- Department of Immunology and Microbiology, National Defense Medical College, Tokorozawa, Japan
| | - Akira Yamagata
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Toshihiko Imakiire
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Manabu Kinoshita
- Department of Immunology and Microbiology, National Defense Medical College, Tokorozawa, Japan
| | - Shuhji Seki
- Department of Immunology and Microbiology, National Defense Medical College, Tokorozawa, Japan
| | - Hiroo Kumagai
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Naoki Oshima
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
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Adhikarla SV, Jha NK, Goswami VK, Sharma A, Bhardwaj A, Dey A, Villa C, Kumar Y, Jha SK. TLR-Mediated Signal Transduction and Neurodegenerative Disorders. Brain Sci 2021; 11:brainsci11111373. [PMID: 34827372 PMCID: PMC8615980 DOI: 10.3390/brainsci11111373] [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: 09/22/2021] [Revised: 10/16/2021] [Accepted: 10/16/2021] [Indexed: 11/16/2022] Open
Abstract
A special class of proteins called Toll-like receptors (TLRs) are an essential part of the innate immune system, connecting it to the adaptive immune system. There are 10 different Toll-Like Receptors that have been identified in human beings. TLRs are part of the central nervous system (CNS), showing that the CNS is capable of the immune response, breaking the long-held belief of the brain's "immune privilege" owing to the blood-brain barrier (BBB). These Toll-Like Receptors are present not just on the resident macrophages of the central nervous system but are also expressed by the neurons to allow them for the production of proinflammatory agents such as interferons, cytokines, and chemokines; the activation and recruitment of glial cells; and their participation in neuronal cell death by apoptosis. This study is focused on the potential roles of various TLRs in various neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD), namely TLR2, TLR3, TLR4, TLR7, and TLR9 in AD and PD in human beings and a mouse model.
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Affiliation(s)
- Shashank Vishwanath Adhikarla
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology (Formerly NSIT, University of Delhi), New Delhi 110078, India;
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
| | - Vineet Kumar Goswami
- Department of Biotechnology, Delhi Technological University, Delhi 110042, India;
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
| | - Ankur Sharma
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
- Department of Life Science, School of Basic Science & Research (SBSR), Sharda University, Greater Noida 201310, India
| | - Anuradha Bhardwaj
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
| | - Abhijit Dey
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India;
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy;
| | - Yatender Kumar
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology (Formerly NSIT, University of Delhi), New Delhi 110078, India;
- Correspondence: (Y.K.); (S.K.J.)
| | - Saurabh Kumar Jha
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
- Correspondence: (Y.K.); (S.K.J.)
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Carroll JA, Race B, Williams K, Striebel JF, Chesebro B. Innate immune responses after stimulation with Toll-like receptor agonists in ex vivo microglial cultures and an in vivo model using mice with reduced microglia. J Neuroinflammation 2021; 18:194. [PMID: 34488805 PMCID: PMC8419892 DOI: 10.1186/s12974-021-02240-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/14/2021] [Indexed: 12/02/2022] Open
Abstract
Background Past experiments studying innate immunity in the central nervous system (CNS) utilized microglia obtained from neonatal mouse brain, which differ developmentally from adult microglia. These differences might impact our current understanding of the role of microglia in CNS development, function, and disease. Methods Cytokine protein secretion was compared in ex vivo P3 and adult microglial cultures after exposure to agonists for three different toll-like receptors (TLR4, lipopolysaccharide [LPS]; TLR7, imiquimod [IMQ]; and TLR9, CpG Oligodeoxynucleotide [CpG-ODN] 1585). In addition, changes in inflammatory gene expression in ex vivo adult microglia in response to the TLR agonists was assessed. Furthermore, in vivo experiments evaluated changes in gene expression associated with inflammation and TLR signaling in brains of mice with or without treatment with PLX5622 to reduce microglia. Results Ex vivo adult and P3 microglia increased cytokine secretion when exposed to TLR4 agonist LPS and to TLR7 agonist IMQ. However, adult microglia decreased expression of numerous genes after exposure to TLR 9 agonist CpG-ODN 1585. In contrast, in vivo studies indicated a core group of inflammatory and TLR signaling genes increased when each of the TLR agonists was introduced into the CNS. Reducing microglia in the brain led to decreased expression of various inflammatory and TLR signaling genes. Mice with reduced microglia showed extreme impairment in upregulation of genes after exposure to TLR7 agonist IMQ. Conclusions Cultured adult microglia were more reactive than P3 microglia to LPS or IMQ exposure. In vivo results indicated microglial influences on neuroinflammation were agonist specific, with responses to TLR7 agonist IMQ more dysregulated in mice with reduced microglia. Thus, TLR7-mediated innate immune responses in the CNS appeared more dependent on the presence of microglia. Furthermore, partial responses to TLR4 and TLR9 agonists in mice with reduced microglia suggested other cell types in the CNS can compensate for their absence. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02240-w.
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Affiliation(s)
- James A Carroll
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT, 59840, USA.
| | - Brent Race
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT, 59840, USA
| | - Katie Williams
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT, 59840, USA
| | - James F Striebel
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT, 59840, USA
| | - Bruce Chesebro
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT, 59840, USA
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12
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Oschwald A, Petry P, Kierdorf K, Erny D. CNS Macrophages and Infant Infections. Front Immunol 2020; 11:2123. [PMID: 33072074 PMCID: PMC7531029 DOI: 10.3389/fimmu.2020.02123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/05/2020] [Indexed: 12/11/2022] Open
Abstract
The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.
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Affiliation(s)
- Alexander Oschwald
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Philippe Petry
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,CIBBS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Daniel Erny
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany
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13
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Abstract
Innate immune cells destroy pathogens within a transient organelle called the phagosome. When pathogen-associated molecular patterns (PAMPs) displayed on the pathogen are recognized by Toll-like receptors (TLRs) on the host cell, it activates inducible nitric oxide synthase (NOS2) which instantly fills the phagosome with nitric oxide (NO) to clear the pathogen. Selected pathogens avoid activating NOS2 by concealing key PAMPs from their cognate TLRs. Thus, the ability to map NOS2 activity triggered by PAMPs can reveal critical mechanisms underlying pathogen susceptibility. Here, we describe DNA-based probes that ratiometrically report phagosomal and endosomal NO, and can be molecularly programmed to display precise stoichiometries of any desired PAMP. By mapping phagosomal NO produced in microglia of live zebrafish brains, we found that single-stranded RNA of bacterial origin acts as a PAMP and activates NOS2 by engaging TLR-7. This technology can be applied to study PAMP-TLR interactions in diverse organisms.
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14
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De Dios R, Nguyen L, Ghosh S, McKenna S, Wright CJ. CpG-ODN-mediated TLR9 innate immune signalling and calcium dyshomeostasis converge on the NFκB inhibitory protein IκBβ to drive IL1α and IL1β expression. Immunology 2020; 160:64-77. [PMID: 32064589 DOI: 10.1111/imm.13182] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/31/2020] [Accepted: 02/11/2020] [Indexed: 12/24/2022] Open
Abstract
Sterile inflammation contributes to many pathological states associated with mitochondrial injury. Mitochondrial injury disrupts calcium homeostasis and results in the release of CpG-rich mitochondrial DNA. The role of CpG-stimulated TLR9 innate immune signalling and sterile inflammation is well studied; however, how calcium dyshomeostasis affects this signalling is unknown. Therefore, we interrogated the relationship beτween intracellular calcium and CpG-induced TLR9 signalling in murine macrophages. We found that CpG-ODN-induced NFκB-dependent IL1α and IL1β expression was significantly attenuated by both calcium chelation and calcineurin inhibition, a finding mediated by inhibition of degradation of the NFκB inhibitory protein IκBβ. In contrast, calcium ionophore exposure increased CpG-induced IκBβ degradation and IL1α and IL1β expression. These results demonstrate that through its effect on IκBβ degradation, increased intracellular Ca2+ drives a pro-inflammatory TLR9-mediated innate immune response. These results have implications for the study of innate immune signalling downstream of mitochondrial stress and injury.
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Affiliation(s)
- Robyn De Dios
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Leanna Nguyen
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sankar Ghosh
- Department of Microbiology & Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Sarah McKenna
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Clyde J Wright
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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15
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Akhmetzyanova E, Kletenkov K, Mukhamedshina Y, Rizvanov A. Different Approaches to Modulation of Microglia Phenotypes After Spinal Cord Injury. Front Syst Neurosci 2019; 13:37. [PMID: 31507384 PMCID: PMC6718713 DOI: 10.3389/fnsys.2019.00037] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 07/29/2019] [Indexed: 01/04/2023] Open
Abstract
Microglial cells, which are highly plastic, immediately respond to any change in the microenvironment by becoming activated and shifting the phenotype toward neurotoxicity or neuroprotection. The polarization of microglia/macrophages after spinal cord injury (SCI) seems to be a dynamic process and can change depending on the microenvironment, stage, course, and severity of the posttraumatic process. Effective methods to modulate microglia toward a neuroprotective phenotype in order to stimulate neuroregeneration are actively sought for. In this context, available approaches that can selectively impact the polarization of microglia/macrophages regulate synthesis of trophic factors and cytokines/chemokines in them, and their phagocytic function and effects on the course and outcome of SCI are discussed in this review.
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Affiliation(s)
- Elvira Akhmetzyanova
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Konstantin Kletenkov
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Yana Mukhamedshina
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia.,Department of Histology, Cytology and Embryology, Kazan State Medical University, Kazan, Russia
| | - Albert Rizvanov
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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16
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Biber K, Bhattacharya A, Campbell BM, Piro JR, Rohe M, Staal RGW, Talanian RV, Möller T. Microglial Drug Targets in AD: Opportunities and Challenges in Drug Discovery and Development. Front Pharmacol 2019; 10:840. [PMID: 31507408 PMCID: PMC6716448 DOI: 10.3389/fphar.2019.00840] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/01/2019] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD) is a large and increasing unmet medical need with no disease-modifying treatment currently available. Genetic evidence from genome-wide association studies (GWASs) and gene network analysis has clearly revealed a key role of the innate immune system in the brain, of which microglia are the most important element. Single-nucleotide polymorphisms (SNPs) in genes predominantly expressed in microglia have been associated with altered risk of developing AD. Furthermore, microglia-specific pathways are affected on the messenger RNA (mRNA) expression level in post-mortem AD tissue and in mouse models of AD. Together these findings have increased the interest in microglia biology, and numerous scientific reports have proposed microglial molecules and pathways as drug targets for AD. Target identification and validation are generally the first steps in drug discovery. Both target validation and drug lead identification for central nervous system (CNS) targets and diseases entail additional significant obstacles compared to peripheral targets and diseases. This makes CNS drug discovery, even with well-validated targets, challenging. In this article, we will illustrate the special challenges of AD drug discovery by discussing the viability/practicality of possible microglia drug targets including cluster of differentiation 33 (CD33), KCa3.1, kynurenines, ionotropic P2 receptor 7 (P2X7), programmed death-1 (PD-1), Toll-like receptors (TLRs), and triggering receptor expressed in myeloid cells 2 (TREM2).
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Affiliation(s)
- Knut Biber
- AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Ludwigshafen, Germany
| | | | | | - Justin R Piro
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
| | - Michael Rohe
- AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Ludwigshafen, Germany
| | | | - Robert V Talanian
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
| | - Thomas Möller
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
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17
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Cell Type Specific Expression of Toll-Like Receptors in Human Brains and Implications in Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7420189. [PMID: 31396533 PMCID: PMC6668540 DOI: 10.1155/2019/7420189] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/07/2019] [Indexed: 12/20/2022]
Abstract
Toll-like receptors mediate important cellular immune responses upon activation via various pathogenic stimuli such as bacterial or viral components. The activation and subsequent secretion of cytokines and proinflammatory factors occurs in the whole body including the brain. The subsequent inflammatory response is crucial for the immune system to clear the pathogen(s) from the body via the innate and adaptive immune response. Within the brain, astrocytes, neurons, microglia, and oligodendrocytes all bear unique compositions of Toll-like receptors. Besides pathogens, cellular damage and abnormally folded protein aggregates, such as tau and Amyloid beta peptides, have been shown to activate Toll-like receptors in neurodegenerative diseases such as Alzheimer's disease. This review provides an overview of the different cell type-specific Toll-like receptors of the human brain, their activation mode, and subsequent cellular response, as well as their activation in Alzheimer's disease. Finally, we critically evaluate the therapeutic potential of targeting Toll-like receptors for treatment of Alzheimer's disease as well as discussing the limitation of mouse models in understanding Toll-like receptor function in general and in Alzheimer's disease.
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18
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Younger D, Murugan M, Rama Rao KV, Wu LJ, Chandra N. Microglia Receptors in Animal Models of Traumatic Brain Injury. Mol Neurobiol 2018; 56:5202-5228. [DOI: 10.1007/s12035-018-1428-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
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19
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Fiebich BL, Batista CRA, Saliba SW, Yousif NM, de Oliveira ACP. Role of Microglia TLRs in Neurodegeneration. Front Cell Neurosci 2018; 12:329. [PMID: 30333729 PMCID: PMC6176466 DOI: 10.3389/fncel.2018.00329] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022] Open
Abstract
Toll-like receptors (TLRs) are a group of receptors widely distributed in the organism. In the central nervous system, they are expressed in neurons, astrocytes and microglia. Although their involvement in immunity is notorious, different articles have demonstrated their roles in physiological and pathological conditions, including neurodegeneration. There is increasing evidence of an involvement of TLRs, especially TLR2, 4 and 9 in neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). In this sense, their expression in microglia might modulate the activity of these cells, which in turn, lead to protective or deleterious effects over neurons and other cells. Therefore, TLRs might mediate the link between inflammation and neurodegenerative diseases. However, further studies have to be performed to elucidate the role of the other TLRs in these diseases and to further prove and confirm the pathophysiological role of all TLRs in neurodegeneration. In this article, we revise and summarize the current knowledge regarding the role of TLRs in neurodegeneration with the focus on the possible functions of these receptors in microglia.
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Affiliation(s)
- Bernd L Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Soraya Wilke Saliba
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Nizar M Yousif
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
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20
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Sato R, Kato A, Chimura T, Saitoh SI, Shibata T, Murakami Y, Fukui R, Liu K, Zhang Y, Arii J, Sun-Wada GH, Wada Y, Ikenoue T, Barber GN, Manabe T, Kawaguchi Y, Miyake K. Combating herpesvirus encephalitis by potentiating a TLR3-mTORC2 axis. Nat Immunol 2018; 19:1071-1082. [PMID: 30201994 DOI: 10.1038/s41590-018-0203-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 07/31/2018] [Indexed: 01/23/2023]
Abstract
TLR3 is a sensor of double-stranded RNA that is indispensable for defense against infection with herpes simplex virus type 1 (HSV-1) in the brain. We found here that TLR3 was required for innate immune responses to HSV-1 in neurons and astrocytes. During infection with HSV-1, TLR3 recruited the metabolic checkpoint kinase complex mTORC2, which led to the induction of chemokines and trafficking of TLR3 to the cell periphery. Such trafficking enabled the activation of molecules (including mTORC1) required for the induction of type I interferons. Intracranial infection of mice with HSV-1 was exacerbated by impairment of TLR3 responses with an inhibitor of mTOR and was significantly 'rescued' by potentiation of TLR3 responses with an agonistic antibody to TLR3. These results suggest that the TLR3-mTORC2 axis might be a therapeutic target through which to combat herpes simplex encephalitis.
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Affiliation(s)
- Ryota Sato
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Akihisa Kato
- Division of Molecular Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takahiko Chimura
- Division of Neuronal Network, Department of Basic Medical Sciences, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Shin-Ichiroh Saitoh
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takuma Shibata
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yusuke Murakami
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Ryutaro Fukui
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kaiwen Liu
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yun Zhang
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Jun Arii
- Division of Molecular Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan
| | - Yoh Wada
- Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Tsuneo Ikenoue
- Division of Clinical Genome Research, Advanced Clinical Research Center, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Glen N Barber
- UM/Sylvester Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Toshiya Manabe
- Division of Neuronal Network, Department of Basic Medical Sciences, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yasushi Kawaguchi
- Division of Molecular Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. .,Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
| | - Kensuke Miyake
- Division of Innate Immunity, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
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21
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Wang S, Cao Y, Deng S, Jiang X, Wang J, Zhang X, Zhang J, Liu G, Lian Z. Overexpression of Toll-like Receptor 4-linked Mitogen-activated Protein Kinase Signaling Contributes to Internalization of Escherichia coli in Sheep. Int J Biol Sci 2018; 14:1022-1032. [PMID: 29989103 PMCID: PMC6036738 DOI: 10.7150/ijbs.25275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/28/2018] [Indexed: 12/17/2022] Open
Abstract
Escherichia coli is one of the most common causal pathogens of mastitis in milk-producing mammals. Toll-like receptor 4 (TLR4) is important for host recognition of this bacteria. Increased activation of TLR4 can markedly enhance the internalization of E. coli. In this study, the relationship between TLR4 and mitogen-activated protein kinase (MAPK) signaling pathways in mediating E. coli internalization was evaluated in sheep monocytes. Using a TLR4-overexpressing transgenic (Tg) sheep model, we explored the bacterial internalization mechanism in sheep. We found that monocytes of Tg sheep could phagocytize more bacteria and exhibited higher adhesive capacity. The specific inhibition of p38 MAPK or c-Jun N-terminal kinase (JNK) or extracellular signal-regulated kinases (ERKs) reduced TLR4-dependent internalization of bacteria into sheep monocytes. Furthermore, the inhibition of MAPK signaling down-regulated the adhesive capacity of monocytes and the expression of scavenger receptors and adhesion molecules. Taken together, the overexpression of TLR4 in transgenic sheep enhanced the internalization of E. coli via MAPK signaling.
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Affiliation(s)
- Sutian Wang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yang Cao
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Shoulong Deng
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiaojing Jiang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Jiahao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | | | - Jinlong Zhang
- Tianjin Institute of Animal Sciences, Tianjin, China
| | - Guoshi Liu
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Zhengxing Lian
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
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22
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Toonen LJA, Casaca-Carreira J, Pellisé-Tintoré M, Mei H, Temel Y, Jahanshahi A, van Roon-Mom WMC. Intracerebroventricular Administration of a 2'-O-Methyl Phosphorothioate Antisense Oligonucleotide Results in Activation of the Innate Immune System in Mouse Brain. Nucleic Acid Ther 2018; 28:63-73. [PMID: 29565739 PMCID: PMC5899290 DOI: 10.1089/nat.2017.0705] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Antisense oligonucleotides (AONs) are versatile molecules that can be used to modulate gene expression by binding to RNA. The therapeutic potential of AONs appears particularly high in the central nervous system, due to excellent distribution and uptake in brain cells, as well as good tolerability in clinical trials thus far. Nonetheless, immune stimulation in response to AON treatment in the brain remains a concern. For this reason we performed RNA sequencing analysis of brain tissue from mice treated intracerebroventricularly with phosphorothioate, 2′-O-methyl modified AONs. A significant upregulation of immune system associated genes was observed in brains of AON treated mice, with the striatum showing largest transcriptional changes. Strongest upregulation was seen for the antiviral enzyme 2′-5′-oligoadenylate synthase-like protein 2 (Oasl2) and Bone marrow stromal antigen 2 (Bst2). Histological analysis confirmed activation of microglia and astrocytes in striatum. The upregulation of immune system associated genes was detectable for at least 2 months after the last AON administration, consistent with a continuous immune response to the AON.
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Affiliation(s)
- Lodewijk J A Toonen
- 1 Department of Human Genetics, Leiden University Medical Center , Leiden, the Netherlands
| | - João Casaca-Carreira
- 2 Department of Neurosurgery, Maastricht University Medical Center , Maastricht, the Netherlands .,3 European Graduate School of Neuroscience (EURON) , Maastricht, the Netherlands .,4 Department of Physiotherapy, Portuguese Red Cross Health School , Lisbon, Portugal .,5 Department of Physiotherapy, School of Health Care , Setubal Polytechnic Institute, Setubal, Portugal
| | - Maria Pellisé-Tintoré
- 2 Department of Neurosurgery, Maastricht University Medical Center , Maastricht, the Netherlands .,6 Department of Medical Science, Faculty of Medicine, University of Girona (UdG) , Girona, Spain
| | - Hailiang Mei
- 7 Sequencing Analysis Support Core, Leiden University Medical Center , Leiden, the Netherlands
| | - Yasin Temel
- 2 Department of Neurosurgery, Maastricht University Medical Center , Maastricht, the Netherlands .,3 European Graduate School of Neuroscience (EURON) , Maastricht, the Netherlands
| | - Ali Jahanshahi
- 2 Department of Neurosurgery, Maastricht University Medical Center , Maastricht, the Netherlands .,3 European Graduate School of Neuroscience (EURON) , Maastricht, the Netherlands
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23
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Lumniczky K, Szatmári T, Sáfrány G. Ionizing Radiation-Induced Immune and Inflammatory Reactions in the Brain. Front Immunol 2017; 8:517. [PMID: 28529513 PMCID: PMC5418235 DOI: 10.3389/fimmu.2017.00517] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/18/2017] [Indexed: 01/17/2023] Open
Abstract
Radiation-induced late brain injury consisting of vascular abnormalities, demyelination, white matter necrosis, and cognitive impairment has been described in patients subjected to cranial radiotherapy for brain tumors. Accumulating evidence suggests that various degrees of cognitive deficit can develop after much lower doses of ionizing radiation, as well. The pathophysiological mechanisms underlying these alterations are not elucidated so far. A permanent deficit in neurogenesis, chronic microvascular alterations, and blood–brain barrier dysfunctionality are considered among the main causative factors. Chronic neuroinflammation and altered immune reactions in the brain, which are inherent complications of brain irradiation, have also been directly implicated in the development of cognitive decline after radiation. This review aims to give a comprehensive overview on radiation-induced immune alterations and inflammatory reactions in the brain and summarizes how these processes can influence cognitive performance. The available data on the risk of low-dose radiation exposure in the development of cognitive impairment and the underlying mechanisms are also discussed.
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Affiliation(s)
- Katalin Lumniczky
- Division of Radiation Medicine, National Public Health Centre, National Research Directorate for Radiobiology and Radiohygiene, Budapest, Hungary
| | - Tünde Szatmári
- Division of Radiation Medicine, National Public Health Centre, National Research Directorate for Radiobiology and Radiohygiene, Budapest, Hungary
| | - Géza Sáfrány
- Division of Radiation Medicine, National Public Health Centre, National Research Directorate for Radiobiology and Radiohygiene, Budapest, Hungary
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Peña-Ortega F. Pharmacological Tools to Activate Microglia and their Possible use to Study Neural Network Patho-physiology. Curr Neuropharmacol 2017; 15:595-619. [PMID: 27697040 PMCID: PMC5543677 DOI: 10.2174/1570159x14666160928151546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are the resident immunocompetent cells of the CNS and also constitute a unique cell type that contributes to neural network homeostasis and function. Understanding microglia cell-signaling not only will reveal their diverse functions but also will help to identify pharmacological and non-pharmacological tools to modulate the activity of these cells. METHODS We undertook a search of bibliographic databases for peer-reviewed research literature to identify microglial activators and their cell-specificity. We also looked for their effects on neural network function and dysfunction. RESULTS We identified several pharmacological targets to modulate microglial function, which are more or less specific (with the proper control experiments). We also identified pharmacological targets that would require the development of new potent and specific modulators. We identified a wealth of evidence about the participation of microglia in neural network function and their alterations in pathological conditions. CONCLUSION The identification of specific microglia-activating signals provides experimental tools to modulate the activity of this heterogeneous cell type in order to evaluate its impact on other components of the nervous system, and it also helps to identify therapeutic approaches to ease some pathological conditions related to microglial dysfunction.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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Cohen S, Ke X, Liu Q, Fu Q, Majnik A, Lane R. Adverse early life environment increases hippocampal microglia abundance in conjunction with decreased neural stem cells in juvenile mice. Int J Dev Neurosci 2016; 55:56-65. [PMID: 27666383 DOI: 10.1016/j.ijdevneu.2016.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Adverse maternal lifestyle resulting in adverse early life environment (AELE) increases risks for neuropsychiatric disorders in offspring. Neuropsychiatric disorders are associated with impaired neurogenesis and neuro-inflammation in the hippocampus (HP). Microglia are neuro-inflammatory cells in the brain that regulate neurogenesis via toll-like receptors (TLR). TLR-9 is implicated in neurogenesis inhibition and is responsible for stress-related inflammatory responses. We hypothesized that AELE would increase microglia cell count and increase TLR-9 expression in juvenile mouse HP. These increases in microglia cell count and TLR-9 expression would be associated with decrease neural stem cell count and neuronal cell count. METHODS We developed a mouse model of AELE combining Western diet and a stress environment. Stress environment consisted of random change from embryonic day 13 (E13) to E17 as well as static change in maternal environment from E13 to postnatal day 21(P21). At P21, we measured hippocampal cell numbers of microglia, neural stem cell and neuron, as well as hippocampal TLR-9 expression. RESULTS AELE significantly increased total microglia number and TLR-9 expression in the hippocampus. Concurrently, AELE significantly decreased neural stem cell and neuronal numbers. CONCLUSIONS AELE increased the neuro-inflammatory cellular response in the juvenile HP. We speculate that increased neuro-inflammatory responses may contribute to impaired neurogenesis seen in this model.
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Affiliation(s)
- Susan Cohen
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Xingrao Ke
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Qiuli Liu
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Qi Fu
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amber Majnik
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Robert Lane
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
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Bowes AL, Yip PK. Modulating inflammatory cell responses to spinal cord injury: all in good time. J Neurotrauma 2014; 31:1753-66. [PMID: 24934600 DOI: 10.1089/neu.2014.3429] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Spinal cord injury can have a range of debilitating effects, permanently impacting a patient's quality of life. Initially thought to be an immune privileged site, the spinal cord is able to mount a timely and well organized inflammatory response to injury. Intricate immune cell interactions are triggered, typically consisting of a staggered multiphasic immune cell response, which can become deregulated if left unchecked. Although several immunomodulatory compounds have yielded success in experimental rodent spinal cord injury models, their translation to human clinical studies needs further consideration. Because temporal differences between rodent and human inflammatory responses to spinal cord injury do exist, drug delivery timing will be a crucial component in recovery from spinal cord injury. Given too early, immunomodulatory therapies may impede beneficial inflammatory reactions to the injured spinal cord or even miss the opportunity to dampen delayed harmful autoimmune processes. Therefore, this review aims to summarize the temporal inflammatory response to spinal cord injury, as well as detailing specific immune cell functions. By clearly defining the chronological order of inflammatory events after trauma, immunomodulatory drug delivery timing can be better optimized. Further, we compare spinal cord injury-induced inflammatory responses in rodent and human studies, enabling clinicians to consider these differences when initiating clinical trials. Improved understanding of the cellular immune response after spinal cord injury would enhance the efficacy of immunomodulatory agents, enabling combined therapies to be considered.
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Affiliation(s)
- Amy L Bowes
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London, United Kingdom
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Pathologic role of glial nitric oxide in adult and pediatric neuroinflammatory diseases. Neurosci Biobehav Rev 2014; 45:168-82. [DOI: 10.1016/j.neubiorev.2014.06.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 05/28/2014] [Accepted: 06/05/2014] [Indexed: 01/22/2023]
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Wu HM, Zhang LF, Ding PS, Liu YJ, Wu X, Zhou JN. Microglial activation mediates host neuronal survival induced by neural stem cells. J Cell Mol Med 2014; 18:1300-12. [PMID: 24725889 PMCID: PMC4124015 DOI: 10.1111/jcmm.12281] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 02/12/2014] [Indexed: 12/19/2022] Open
Abstract
The rational of neural stem cells (NSCs) in the therapy of neurological disease is either to replace dead neurons or to improve host neuronal survival, the latter of which has got less attention and the underlying mechanism is as yet little known. Using a transwell co-culture system, we reported that, in organotypic brain slice cultures, NSCs significantly improved host neuronal viability. Interestingly, this beneficial effect of NSCs was abrogated by a microglial inhibitor minocycline, while it was mimicked by a microglial agonist, Toll-like receptor 9 (TLR9) ligand CpG-ODN, which supports the pro-vital mediation by microglia on this NSCs-improved neuronal survival. Moreover, we showed that NSCs significantly induced host microglial movement and higher expression of a microglial marker IBA-1, the latter of which was positively correlated with TLR9 or extracellular-regulated protein kinases 1/2 (ERK1/2) activation. Real-time PCR revealed that NSCs inhibited the expression of pro-inflammatory molecules, but significantly increased the expression of molecules associated with a neuroprotective phenotype such as CX3CR1, triggering receptor expressed on myeloid cells-2 (TREM2) and insulin growth factor 1 (IGF-1). Similarly, in the microglia cells, NSCs induced the same microglial response as that in the slices. Further treatment with TLR9 ligand CpG-ODN, TLR9 inhibitor chloroquine (CQ) or ERK1/2 inhibitor U0126 demonstrated that TLR9-ERK1/2 pathway was involved in the NSCs-induced microglial activation. Collectively, this study indicated that NSCs improve host neuronal survival by switching microglia from a detrimental to a neuroprotective phenotype in adult mouse brain, and the microglial TLR9-ERK1/2 pathway seems to participate in this NSCs-mediated rescue action.
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Affiliation(s)
- Hui-Mei Wu
- CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China; Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
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Draleau K, Maddula S, Slaiby A, Nutile-McMenemy N, De Leo J, Cao L. Phenotypic Identification of Spinal Cord-Infiltrating CD4 + T Lymphocytes in a Murine Model of Neuropathic Pain. ACTA ACUST UNITED AC 2014; Suppl 3:003. [PMID: 25143871 PMCID: PMC4136538 DOI: 10.4172/2167-0846.s3-003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Neuropathic pain is one of the most devastating kinds of chronic pain. Neuroinflammation has been shown to contribute to the development of neuropathic pain. We have previously demonstrated that lumbar spinal cord-infiltrating CD4+ T lymphocytes contribute to the maintenance of mechanical hypersensitivity in spinal nerve L5 transection (L5Tx), a murine model of neuropathic pain. Here, we further examined the phenotype of the CD4+ T lymphocytes involved in the maintenance of neuropathic pain-like behavior via intracellular flow cytometric analysis and explored potential interactions between infiltrating CD4+ T lymphocytes and spinal cord glial cells. RESULTS We consistently observed significantly higher numbers of T-Bet+, IFN-γ+, TNF-α+, and GM-CSF+, but not GATA3+ or IL-4+, lumbar spinal cord-infiltrating CD4+ T lymphocytes in the L5Tx group compared to the sham group at day 7 post-L5Tx. This suggests that the infiltrating CD4+ T lymphocytes expressed a pro-inflammatory type 1 phenotype (Th1). Despite the observation of CD4+ CD40 ligand (CD154)+ T lymphocytes in the lumbar spinal cord post-L5Tx, CD154 knockout (KO) mice did not display significant changes in L5Tx-induced mechanical hypersensitivity, indicating that T lymphocyte-microglial interaction through the CD154-CD40 pathway is not necessary for L5Tx-induced hypersensitivity. In addition, spinal cord astrocytic activation, represented by glial fibillary acidic protein (GFAP) expression, was significantly lower in CD4 KO mice compared to wild type (WT) mice at day 14 post-L5Tx, suggesting the involvement of astrocytes in the pronociceptive effects mediated by infiltrating CD4+ T lymphocytes. CONCLUSIONS In all, these data indicate that the maintenance of L5Tx-induced neuropathic pain is mostly mediated by Th1 cells in a CD154-independent manner via a mechanism that could involve multiple Th1 cytokines and astrocytic activation.
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Affiliation(s)
- Ks Draleau
- Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, 04005, USA
| | - S Maddula
- Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, 04005, USA
| | - A Slaiby
- Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, 04005, USA
| | - N Nutile-McMenemy
- Department of Anesthesiology, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Ja De Leo
- Department of Anesthesiology, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA ; Vice President of Academic Affairs, Professor of Biology, Emmanuel College, 400 The Fenway, Boston, MA 02215, USA
| | - L Cao
- Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, 04005, USA
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Treg depletion followed by intracerebral CpG-ODN injection induce brain tumor rejection. J Neuroimmunol 2013; 267:35-42. [PMID: 24369298 DOI: 10.1016/j.jneuroim.2013.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/31/2013] [Accepted: 12/04/2013] [Indexed: 12/21/2022]
Abstract
Using brain lymphoma model, we demonstrate that immunotherapy combining Treg depletion (using anti-CD25 mAb PC61) followed by intracranial CpG-ODN administration induced tumor rejection in all treated mice and led to the establishment of a memory antitumor immune response in 60% of them. This protective effect was associated with a recruitment of NK cells and, to a lesser extent, of dendritic cells, B cells and T lymphocytes. NK cell depletion abolished the protective effect of the treatment, confirming a major role of NK cells in brain tumor elimination. Each treatment used alone failed to protect brain tumor bearing mice, revealing the therapeutic benefit of combining Treg depletion and local CpG-ODN injection.
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31
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The controversial role of microglia in malignant gliomas. Clin Dev Immunol 2013; 2013:285246. [PMID: 23983766 PMCID: PMC3741958 DOI: 10.1155/2013/285246] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/19/2013] [Indexed: 01/01/2023]
Abstract
Malignant gliomas contain stroma and a variety of immune cells including abundant activated microglia/macrophages. Mounting evidence indicates that the glioma microenvironment converts the glioma-associated microglia/macrophages (GAMs) into glioma-supportive, immunosuppressive cells; however, GAMs can retain intrinsic anti-tumor properties. Here, we review and discuss this duality and the potential therapeutic strategies that may inhibit their glioma-supportive and propagating functions.
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Acevedo G, Padala NK, Ni L, Jonakait GM. Astrocytes inhibit microglial surface expression of dendritic cell-related co-stimulatory molecules through a contact-mediated process. J Neurochem 2013; 125:575-87. [PMID: 23439211 DOI: 10.1111/jnc.12221] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 02/08/2013] [Accepted: 02/08/2013] [Indexed: 12/25/2022]
Abstract
Murine microglia cultured in isolation were treated sequentially with granulocyte/monocyte colony-stimulating factor (GM-CSF) (5 days) and lipopolysaccharide (LPS) (2 days) to elicit a mature dendritic cell-like (DC-like) phenotype. Examined by flow cytometry microglia thus isolated show high surface expression of CD11c together with the co-stimulatory molecules CD40, CD80, and CD86 that are necessary for T-cell activation. In contrast, microglia co-cultured with astrocytes fail to achieve a mature DC-like phenotype. Contact with the astrocytic environment is necessary for the inhibition. Failure was not because of a more rapid degradation of protein. Bone marrow-derived cells, like microglia, were prevented by astrocytes from attaining a mature DC phenotype. Although GM-CSF pre-treatment substantially increases mRNA of co-stimulatory molecules and major histocompatibility complex (MHC) Class II in isolated microglia, co-cultured microglia await treatment with LPS to up-regulate them. In contrast, western blot and immunocytochemical analysis revealed that it is not a failure of transcription or translation, nor is it a more rapid degradation of mRNA that is responsible for the low surface expression; rather microglia co-cultured with astrocytes produce mRNA and protein but do not traffic the protein onto the cell surface.
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David BT, Ratnayake A, Amarante MA, Reddy NP, Dong W, Sampath S, Heary RF, Elkabes S. A toll-like receptor 9 antagonist reduces pain hypersensitivity and the inflammatory response in spinal cord injury. Neurobiol Dis 2013; 54:194-205. [PMID: 23313320 DOI: 10.1016/j.nbd.2012.12.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/11/2012] [Accepted: 12/28/2012] [Indexed: 12/20/2022] Open
Abstract
Toll-like receptors (TLRs) are mediators of the innate immune response to exogenous pathogens. They have also been implicated in sterile inflammation associated with systemic injury and non-infectious diseases via binding of endogenous ligands, possibly released by damaged cells. Emerging evidence indicates that some TLRs play a role in nervous system injury and especially in injury-elicited pain and sterile inflammation. However, no information is available about the contribution of TLR9, a member of the TLR family, to traumatic spinal cord injury (SCI). Moreover, the therapeutic potential of TLR9 ligands in the functional outcomes of SCI, including pain, has not been explored. We report, for the first time, that the intrathecal administration of a TLR9 antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), to mice sustaining a severe contusion SCI, diminishes injury-induced heat hypersensitivity. Investigations on the potential mechanisms underlying the reduction in pain sensitivity indicated an attenuation of the inflammatory reaction manifested by a decrease in the number of CD11b-, CD45- and CD3-immunoreactive cells and a reduction in tumor necrosis factor-α (TNF-α) expression at the epicenter. Conversely, intrathecal delivery of a TLR9 agonist, CpG ODN 1826, increased inflammatory cell numbers and TNF-α expression in the epicenter. The CpG ODN 2088 treatment did not appear to induce systemic adverse effects as shown by spleen histology and serum cytokine levels. We propose that CpG ODN 2088 dampens injury-induced heat hypersensitivity by suppressing the inflammatory response and TNF-α expression. This investigation defines a previously unreported therapeutic role for CpG ODN 2088 in SCI-induced pain.
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Affiliation(s)
- Brian T David
- Department of Neurological Surgery, New Jersey Medical School, Newark, NJ 07103, USA
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Cao L, Beaulac H, Eurich A. Differential lumbar spinal cord responses among wild type, CD4 knockout, and CD40 knockout mice in spinal nerve L5 transection-induced neuropathic pain. Mol Pain 2012; 8:88. [PMID: 23249743 PMCID: PMC3545955 DOI: 10.1186/1744-8069-8-88] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/14/2012] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Our previous studies have indicated that both lumbar spinal cord-infiltrating CD4+ T cells and microglial CD40 contribute to the maintenance of mechanical hypersensitivity in a murine model of neuropathic pain spinal nerve L5 transection (L5Tx). To further delineate the CD4 and CD40-mediated mechanisms involved in the development of L5Tx-induced neuropathic pain behaviors, we examined the lumbar spinal cord mononuclear cells of wild type (WT) BALB/c, BALB/c-CD4 knockout (KO), and BALB/c-CD40 KO mice via flow cytometry. RESULTS In WT mice, L5Tx induced significant but transient (at day 3 and/or day 7) increases of the total numbers of mononuclear cells, microglial cells (CD45loCD11b+), and infiltrating leukocytes (CD45hi) in the ipsilateral side of the spinal cord. In CD4 KO mice, significant elevation of microglia was detected only on day 7 post-L5Tx, while no significant increase in infiltrating leukocytes post-L5Tx was observed. CD40 KO mice did not exhibit any of the changes observed in WT mice. Furthermore, neutralizing CD40 antibody treatment indicated an early involvement of CD40 signaling in the development of L5Tx-induced mechanical hypersensitivity. CONCLUSIONS Altogether, data indicate that both CD4 and CD40 play a role in L5Tx-induced leukocyte infiltration into the lumbar spinal cord but have differential contributions to spinal cord microglial activation following peripheral nerve injury.
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Affiliation(s)
- Ling Cao
- Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, USA.
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35
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Abstract
Toll-like receptors (TLRs) are germline-encoded pattern-recognition receptors that initiate innate immune responses by recognizing molecular structures shared by a wide range of pathogens, known as pathogen-associated molecular patterns (PAMPs). After tissue injury or cellular stress, TLRs also detect endogenous ligands known as danger-associated molecular patterns (DAMPs). TLRs are expressed in both non-neuronal and neuronal cell types in the central nervous system (CNS) and contribute to both infectious and non-infectious disorders in the CNS. Following tissue insult and nerve injury, TLRs (such as TLR2, TLR3, and TLR4) induce the activation of microglia and astrocytes and the production of the proinflammatory cytokines in the spinal cord, leading to the development and maintenance of inflammatory pain and neuropathic pain. In particular, primary sensory neurons, such as nociceptors, express TLRs (e.g., TLR4 and TLR7) to sense exogenous PAMPs and endogenous DAMPs released after tissue injury and cellular stress. These neuronal TLRs are new players in the processing of pain and itch by increasing the excitability of primary sensory neurons. Given the prevalence of chronic pain and itch and the suffering of affected people, insights into TLR signaling in the nervous system will open a new avenue for the management of clinical pain and itch.
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Hopkins RA, Connolly JE. The specialized roles of immature and mature dendritic cells in antigen cross-presentation. Immunol Res 2012; 53:91-107. [PMID: 22450675 DOI: 10.1007/s12026-012-8300-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Exogenous antigen cross-presentation is integral to the stimulation of cytotoxic T-lymphocytes against viruses and tumors. Central to this process are dendritic cells (DCs), which specialize in cross-presentation. DCs may be considered to exist in two radically different states of activation, generally referred to as immature and mature. In each of these states, the cell has a series of separate and specialized abilities for the induction of T-cell immunity. In the immature state, the DC is adept in surveying the periphery, acquiring and storing antigen, but has a limited capacity for direct T-cell activation. During a brief and defined window of time following DC stimulation, nearly every aspect of antigen handling changes, as it transitions from an entity focused on protein preservation to one capable of efficient cross-presentation. It is this time period and the underlying molecular mechanisms active here, which form the core of our studies on cross-presentation.
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Affiliation(s)
- Richard A Hopkins
- Program in Translational Immunology, Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #03 Immunos, Biopolis, Singapore
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Brandenburg LO, Jansen S, Albrecht LJ, Merres J, Gerber J, Pufe T, Tauber SC. CpG oligodeoxynucleotides induce the expression of the antimicrobial peptide cathelicidin in glial cells. J Neuroimmunol 2012; 255:18-31. [PMID: 23141747 DOI: 10.1016/j.jneuroim.2012.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 11/26/2022]
Abstract
During bacterial infections, antimicrobial peptides are synthesised as an important part of the innate immune system. However, expression and function in the central nervous system (CNS) need further investigations. The aim of this study was to examine the involvement of the pattern-recognition-receptor toll-like receptor 9 (TLR9) in the expression of the cathelin-related antimicrobial peptide (CRAMP) and to characterise the participating signal transduction pathways. In primary TLR9 deficient and wildtype mice astrocytes as well as microglia cells, the expression of CRAMP after treatment with the TLR9 agonist unmethylated cytosine-guanine oligodeoxynucleotide motifs (CpG-DNA) was examined in vitro. In vivo CRAMP expression after intraventricular infusion of CpG-DNA in TLR9 deficient and wildtype mice as well as in mice with pneumococcal meningitis localised in glial cells was determined. Furthermore, the regulation of different signal transduction pathways involved in CpG-DNA-induced CRAMP expression in glial cells was analysed. An in vitro and in vivo CpG-DNA-induced increase of CRAMP expression in astrocytes and microglia cells using real time RT-PCR and immunofluorescence was demonstrated. Different signal transduction pathways such as mitogen-activated protein kinases and inflammatory mediated pathways are involved in the expression of CRAMP in primary glial cells. Interestingly, TLR9-deficient glial cells showed a reduced but not completely abolished CRAMP mRNA expression and ERK1/2 phosphorylation in response to CpG-DNA treatment. On the other side in vivo, TLR9 deletion did not change CRAMP expression after bacterial infection. In conclusion, our results show that TLR9 can induce the expression of antimicrobial peptides such as CRAMP in response to bacterial DNA motifs in primary glial cells. Additional findings suggest also that CpG-DNA-induced effects are not only mediated by TLR9, but also mediated by other pattern recognition receptors.
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Fan H, Zhang I, Chen X, Zhang L, Wang H, Da Fonseca A, Manuel ER, Diamond DJ, Raubitschek A, Badie B. Intracerebral CpG immunotherapy with carbon nanotubes abrogates growth of subcutaneous melanomas in mice. Clin Cancer Res 2012; 18:5628-38. [PMID: 22904105 DOI: 10.1158/1078-0432.ccr-12-1911] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Recently, we showed that intratumoral delivery of low-dose, immunostimulatory CpG oligodeoxynucleotides conjugated with carbon nanotubes (CNT-CpG) was more effective than free CpG and not only eradicated intracranial (i.c.) gliomas but also induced antitumor immunity that protected mice from subsequent i.c. or systemic tumor rechallenge. Here, we examined whether the same "intracerebral immunotherapy" strategy could be applied to the treatment of metastatic brain tumors. EXPERIMENTAL DESIGN Mice with both i.c. and s.c. melanomas were injected intratumorally with CNT-CpG into either location. Antitumor responses were assessed by flow cytometry, bioluminescent imaging, and animal survival. RESULTS When given s.c., CNT-CpG response was mostly local, and it only modestly inhibited the growth of i.c. melanomas. However, i.c. CNT-CpG abrogated the growth of not only brain but also s.c. tumors. Furthermore, compared with s.c. injections, i.c. CNT-CpG elicited a stronger inflammatory response that resulted in more potent antitumor cytotoxicity and improved in vivo trafficking of effector cells into both i.c. and s.c. tumors. To investigate factors that accounted for these observations, CNT-CpG biodistribution and cellular inflammatory responses were examined in both tumor locations. Intracranial melanomas retained the CNT-CpG particles longer and were infiltrated by Toll-like receptor (TLR-9)-positive microglia. In contrast, myeloid-derived suppressive cells were more abundant in s.c. tumors. Although depletion of these cells before s.c. CNT-CpG therapy enhanced its cytotoxic responses, antitumor responses to brain melanomas were unchanged. CONCLUSIONS These findings suggest that intracerebral CNT-CpG immunotherapy is more effective than systemic therapy in generating antitumor responses that target both brain and systemic melanomas.
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Affiliation(s)
- Haitao Fan
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong University, Jinan, PR China
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Schiller M, Parcina M, Heyder P, Foermer S, Ostrop J, Leo A, Heeg K, Herrmann M, Lorenz HM, Bekeredjian-Ding I. Induction of type I IFN is a physiological immune reaction to apoptotic cell-derived membrane microparticles. THE JOURNAL OF IMMUNOLOGY 2012; 189:1747-56. [PMID: 22786771 DOI: 10.4049/jimmunol.1100631] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Membrane microparticles (MMP) released from apoptotic cells deliver signals that secure the anti-inflammatory response beyond the nearest proximity of the apoptotic cell. Plasmacytoid dendritic cells (pDC) are sentinels prepared to detect cellular processes that endanger the organism. They play a key role in the regulation of both pro- and anti-inflammatory immune responses. Based on the assumption that pDC could participate in the initiation of the anti-inflammatory response to apoptotic cells, we investigated the effects of apoptotic cell-derived MMP on human pDC. The results obtained in our experiments confirmed that MMP released from apoptotic cells trigger IFN-α secretion from human pDC. They further suggest that pDC activation results from sensing of DNA contained in MMP. MMP-DNA displays a particularly strong stimulatory activity compared with MMP-RNA and other sources of DNA. Inhibition of MMP-induced IFN-α secretion by cytochalasin D, chloroquine, and an inhibitory G-rich oligodeoxynucleotide identify TLR9 as the receptor for MMP-DNA. In marked contrast to the pDC response in autoimmune patients, in healthy subjects MMP-mediated stimulation of pDC-derived IFN-α was found to be independent of FcγRIIA (CD32A). Based on our findings, we conclude that induction of pDC-derived IFN-α by MMP is a physiological event; future investigations are necessary to elucidate whether pDC activation promotes inflammation or propagates tolerance in the context of apoptotic cell clearance.
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Affiliation(s)
- Martin Schiller
- Division of Rheumatology, Department of Internal Medicine V, University Hospital Heidelberg, D-69120 Heidelberg, Germany.
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Sweepers in the CNS: Microglial Migration and Phagocytosis in the Alzheimer Disease Pathogenesis. Int J Alzheimers Dis 2012; 2012:891087. [PMID: 22666624 PMCID: PMC3359803 DOI: 10.1155/2012/891087] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/02/2012] [Indexed: 01/28/2023] Open
Abstract
Microglia are multifunctional immune cells in the central nervous system (CNS). In the neurodegenerative diseases such as Alzheimer's disease (AD), accumulation of glial cells, gliosis, occurs in the lesions. The role of accumulated microglia in the pathophysiology of AD is still controversial. When neuronal damage occurs, microglia exert diversified functions, including migration, phagocytosis, and production of various cytokines and chemokines. Among these, microglial phagocytosis of unwanted neuronal debris is critical to maintain the healthy neuronal networks. Microglia express many surface receptors implicated in phagocytosis. It has been suggested that the lack of microglial phagocytosis worsens pathology of AD and induces memory impairment. The present paper summarizes recent evidences on implication of microglial chemotaxis and phagocytosis in AD pathology and discusses the mechanisms related to chemotaxis toward injured neurons and phagocytosis of unnecessary debris.
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The biphasic role of microglia in Alzheimer's disease. Int J Alzheimers Dis 2012; 2012:737846. [PMID: 22655214 PMCID: PMC3357927 DOI: 10.1155/2012/737846] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 02/29/2012] [Indexed: 01/05/2023] Open
Abstract
Neuroinflammation is involved in the pathogenesis of Alzheimer's disease (AD). Microglia, macrophage-like resident immune cells in the brain, play critical roles in the inflammatory aspects of AD. Microglia may be activated by oligomeric and fibrillar species of amyloid β (Aβ) that are constituents of senile plaques and by molecules derived from degenerated neurons, such as purines and chemokines, which enhance their migration and phagocytosis. The main neurotoxic molecules produced by activated microglia may be reactive oxygen species, glutamate, and inflammatory cytokines such as tumor-necrosis-factor-α and interleukin- (IL-) 1β These molecules differentially induce neurotoxicity. Aβ itself directly damages neurons. In terms of neuroprotective properties, microglia treated with fractalkine or IL-34 attenuate Aβ neurotoxicity by Aβ clearance and the production of antioxidants. Therefore, regulation of the microglial role in neuroprotection may be a useful therapeutic strategy for AD.
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Hjorth E, Freund-Levi Y. Immunomodulation of microglia by docosahexaenoic acid and eicosapentaenoic acid. Curr Opin Clin Nutr Metab Care 2012; 15:134-43. [PMID: 22316559 DOI: 10.1097/mco.0b013e32835017cc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The omega-3 fatty acids (ω-3 FAs) docosahexaenoic acid and eicosapentaenoic acid are dietary components which have been ascribed many different health benefits. Inflammation is present in, and contributes to, pathological conditions in the central nervous system (CNS). Microglia are the primary cells with immune function in the CNS, and inflammation mediated by activated microglia is present in pathological conditions. In this review, we present and discuss findings on the modulation of microglial activities by ω-3 FAs in vivo as well as in vitro, and propose mechanisms for their effects. RECENT FINDINGS The majority of studies show that ω-3 FAs have anti-inflammatory effects on microglia. However, phagocytosis is an activity associated with inflammation and is increased by ω-3 FAs. This can be understood in the light of recent research on the resolution of inflammation. Resolution is induced by proresolving factors, which are metabolites of ω-3 FAs. Proresolving factors are anti-inflammatory and have been shown to increase phagocytosis. Other mechanisms of the anti-inflammatory actions of ω-3 FAs involve the peroxisome proliferator-activated receptor-γ, ω-3 FA incorporation into the cell membrane, and inhibition of ion currents. SUMMARY Immunomodulation by ω-3 FAs is mediated by several pathways that are interconnected and is a potential therapy for disorders in the CNS.
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Affiliation(s)
- Erik Hjorth
- Division of Neurodegeneration, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
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Involvement of calcitonin gene-related peptide and CCL2 production in CD40-mediated behavioral hypersensitivity in a model of neuropathic pain. ACTA ACUST UNITED AC 2012; 7:117-28. [PMID: 22377050 DOI: 10.1017/s1740925x12000026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The neuropeptide calcitonin gene-related peptide (CGRP) is known to play a pro-nociceptive role after peripheral nerve injury upon its release from primary afferent neurons in preclinical models of neuropathic pain. We previously demonstrated a critical role for spinal cord microglial CD40 in the development of spinal nerve L5 transection (L5Tx)-induced mechanical hypersensitivity. Herein, we investigated whether CGRP is involved in the CD40-mediated behavioral hypersensitivity. First, L5Tx was found to significantly induce CGRP expression in wild-type (WT) mice up to 14 days post-L5Tx. This increase in CGRP expression was reduced in CD40 knockout (KO) mice at day 14 post-L5Tx. Intrathecal injection of the CGRP antagonist CGRP8-37 significantly blocked L5Tx-induced mechanical hypersensitivity. In vitro, CGRP induced glial IL-6 and CCL2 production, and CD40 stimulation added to the effects of CGRP in neonatal glia. Further, there was decreased CCL2 production in CD40 KO mice compared to WT mice 21 days post-L5Tx. However, CGRP8-37 did not significantly affect spinal cord CCL2 production following L5Tx in WT mice. Altogether, these data suggest that CD40 contributes to the maintenance of behavioral hypersensitivity following peripheral nerve injury in part through two distinct pathways, the enhancement of CGRP expression and spinal cord CCL2 production.
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Inhibition of TLR ligand- and interferon gamma-induced murine microglial activation by Panax notoginseng. J Neuroimmune Pharmacol 2011; 7:465-76. [PMID: 22183805 DOI: 10.1007/s11481-011-9333-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 12/06/2011] [Indexed: 01/28/2023]
Abstract
Among the many products which influence microglial activation and resulting neuroinflammation, herbal medicine has recently drawn much attention due to its immunomodulatory and neuroprotective activities. The purpose of the current study was to investigate the effects of an extract of Panax notoginseng (NotoG™) on TLR ligand- and IFNγ-induced activation in N9 and EOC20 microglial cells lines. NotoG suppressed microglial activation as measured by reduced expression of accessory molecules (CD40 and CD86), decreased production of inflammatory mediators (IL-6 and TNFα), and diminished release of antibacterial products (nitric oxide). Furthermore, this immunosuppressive activity was neither dependent on the glucocorticoid receptor, nor the result of a single ginsenosides (Rb1, Rg1, or Re), which are the major active constituents of the whole extract. NotoG and select ginsenosides may therefore be of therapeutic benefit in treating or preventing neurodegenerative diseases such as multiple sclerosis and parkinson's disease.
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Role of specific innate immune responses in herpes simplex virus infection of the central nervous system. J Virol 2011; 86:2273-81. [PMID: 22171256 DOI: 10.1128/jvi.06010-11] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) causes a spectrum of disease, including herpes labialis, herpes keratitis, and herpes encephalitis, which can be lethal. Viral recognition by pattern recognition receptors plays a central role in cytokine production and in the generation of antiviral immunity. The relative contributions of different Toll-like receptors (TLRs) in the innate immune response during central nervous system infection with HSV-1 have not been fully characterized. In this study, we investigate the roles of TLR2, TLR9, UNC93B1, and the type I interferon (IFN) receptor in a murine model of HSV-1 encephalitis. TLR2 is responsible for detrimental inflammatory cytokine production following intracranial infection with HSV-1, and the absence of TLR2 expression leads to increased survival in mice. We prove that inflammatory cytokine production by microglial cells, astrocytes, neutrophils, and monocytes is mediated predominantly by TLR2. We also demonstrate that type I IFNs are absolutely required for survival following intracranial HSV-1 infection, as mice lacking the type I IFN receptor succumb rapidly following infection and have high levels of HSV in the brain. However, the absence of TLR9 does not impact survival, type I IFN levels, or viral replication in the brain following infection. The absence of UNC93B1 leads to a survival disadvantage but does not impact viral replication or type I IFN levels in the brain in HSV-1-infected mice. These results illustrate the complex but important roles that innate immune receptors play in host responses to HSV-1 during infection of the central nervous system.
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Chinnery HR, McLenachan S, Binz N, Sun Y, Forrester JV, Degli-Esposti MA, Pearlman E, McMenamin PG. TLR9 ligand CpG-ODN applied to the injured mouse cornea elicits retinal inflammation. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:209-20. [PMID: 22085974 DOI: 10.1016/j.ajpath.2011.09.041] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 09/11/2011] [Accepted: 09/14/2011] [Indexed: 11/15/2022]
Abstract
During bacterial and viral infections, unmethylated CpG-DNA released by proliferating and dying microbes is recognized by toll-like receptor (TLR) 9 in host cells, initiating innate immune responses. Many corneal infections occur secondary to epithelial breaches and represent a major cause of vision impairment and blindness globally. To mimic this clinical situation, we investigated mechanisms of TLR9 ligand-induced corneal inflammation in mice after epithelial debridement. Application of CpG oligodeoxynucleotides (ODNs) resulted in neutrophil and macrophage infiltration to the cornea and loss of transparency. By 6 hours after CpG-ODN administration, TLR9 mRNA was increased in the cornea and retina. In vivo clinical examination at 24 hours revealed inflammatory infiltrates in the vitreous and retina, which were confirmed ex vivo to be neutrophils and macrophages, along with activated resident microglia. CpG-ODN-induced intraocular inflammation was abrogated in TLR9(-/-) and macrophage-depleted mice. Bone marrow reconstitution of irradiated TLR9(-/-) mice with TLR9(+/+) bone marrow led to restored corneal inflammatory responses to CpG-ODN. Fluorescein isothiocyanate-CpG-ODN rapidly penetrated the cornea and ocular media to reach the retina, where it was present within CD68(+) retinal macrophages and microglia. These data show that topically applied CpG-ODN induces intraocular inflammation owing to TLR9 activation of monocyte-lineage cells. These novel findings indicate that microbial CpG-DNA released during bacterial and/or viral keratitis can cause widespread inflammation within the eye, including the retina.
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Affiliation(s)
- Holly R Chinnery
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Clayton, VIC, Australia
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Hanke ML, Kielian T. Toll-like receptors in health and disease in the brain: mechanisms and therapeutic potential. Clin Sci (Lond) 2011; 121:367-87. [PMID: 21745188 PMCID: PMC4231819 DOI: 10.1042/cs20110164] [Citation(s) in RCA: 367] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The discovery of mammalian TLRs (Toll-like receptors), first identified in 1997 based on their homology with Drosophila Toll, greatly altered our understanding of how the innate immune system recognizes and responds to diverse microbial pathogens. TLRs are evolutionarily conserved type I transmembrane proteins expressed in both immune and non-immune cells, and are typified by N-terminal leucine-rich repeats and a highly conserved C-terminal domain termed the TIR [Toll/interleukin (IL)-1 receptor] domain. Upon stimulation with their cognate ligands, TLR signalling elicits the production of cytokines, enzymes and other inflammatory mediators that can have an impact on several aspects of CNS (central nervous system) homoeostasis and pathology. For example, TLR signalling plays a crucial role in initiating host defence responses during CNS microbial infection. Furthermore, TLRs are targets for many adjuvants which help shape pathogen-specific adaptive immune responses in addition to triggering innate immunity. Our knowledge of TLR expression and function in the CNS has greatly expanded over the last decade, with new data revealing that TLRs also have an impact on non-infectious CNS diseases/injury. In particular, TLRs recognize a number of endogenous molecules liberated from damaged tissues and, as such, influence inflammatory responses during tissue injury and autoimmunity. In addition, recent studies have implicated TLR involvement during neurogenesis, and learning and memory in the absence of any underlying infectious aetiology. Owing to their presence and immune-regulatory role within the brain, TLRs represent an attractive therapeutic target for numerous CNS disorders and infectious diseases. However, it is clear that TLRs can exert either beneficial or detrimental effects in the CNS, which probably depend on the context of tissue homoeostasis or pathology. Therefore any potential therapeutic manipulation of TLRs will require an understanding of the signals governing specific CNS disorders to achieve tailored therapy.
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Affiliation(s)
- Mark L. Hanke
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Tammy Kielian
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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Schmidt KE, Schumak B, Specht S, Dubben B, Limmer A, Hoerauf A. Induction of pro-inflammatory mediators in Plasmodium berghei infected BALB/c mice breaks blood-brain-barrier and leads to cerebral malaria in an IL-12 dependent manner. Microbes Infect 2011; 13:828-36. [PMID: 21609776 DOI: 10.1016/j.micinf.2011.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/24/2011] [Accepted: 04/18/2011] [Indexed: 01/07/2023]
Abstract
A severe complication of Plasmodium infection is cerebral malaria, a condition mainly attributed to overwhelming inflammatory immune reactions of the host. Murine models differing in susceptibility to experimental cerebral malaria (ECM) allow detailed studies of the host response. We show that ECM- resistant BALB/c mice were driven into interferon gamma- and IL-12-dependent ECM and subsequent death if they received CpG-oligonucleotides after Plasmodium berghei ANKA (PbA) infection. CpG application triggered production of pro-inflammatory cytokines systemically as well in spleen and brain and induced neuropathological symptoms, leading to increased mortality. Experiments with genetically deficient mice confirmed the role of IFN-γ and IL-12 during CpG-triggered immunopathology. Furthermore, the application of CpG and downstream production of pro-inflammatory cytokines contributed to the break down of the blood brain barrier visualized by Evan's Blue, comparable to PbA-infected C57BL/6 mice. Taken together, resistance of BALB/c mice towards ECM development could be altered through induction of pro-inflammatory cytokines by CpG. Therefore, approaches discussed earlier to induce pro-inflammatory immune reactions for malaria protection should be considered with caution.
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Affiliation(s)
- Kim E Schmidt
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany
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Chastain EML, Duncan DS, Rodgers JM, Miller SD. The role of antigen presenting cells in multiple sclerosis. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1812:265-74. [PMID: 20637861 PMCID: PMC2970677 DOI: 10.1016/j.bbadis.2010.07.008] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 07/06/2010] [Accepted: 07/07/2010] [Indexed: 12/25/2022]
Abstract
Multiple sclerosis (MS) is a debilitating T cell mediated autoimmune disease of the central nervous system (CNS). Animal models of MS, such as experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) have given light to cellular mechanisms involved in the initiation and progression of this organ-specific autoimmune disease. Within the CNS, antigen presenting cells (APC) such as microglia and astrocytes participate as first line defenders against infections or inflammation. However, during chronic inflammation they can participate in perpetuating the self-destructive environment by secretion of inflammatory factors and/or presentation of myelin epitopes to autoreactive T cells. Dendritic cells (DC) are also participants in the presentation of antigen to T cells, even within the CNS. While the APCs alone are not solely responsible for mediating the destruction to the myelin sheath, they are critical players in perpetuating the inflammatory milieu. This review will highlight relevant studies which have provided insight to the roles played by microglia, DCs and astrocytes in the context of CNS autoimmunity.
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Affiliation(s)
- Emily M L Chastain
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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