51
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: catalytic receptors. Br J Pharmacol 2014; 170:1676-705. [PMID: 24528241 PMCID: PMC3892291 DOI: 10.1111/bph.12449] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Catalytic receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
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52
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Popa-Wagner A, Buga AM, Tica AA, Albu CV. Perfusion deficits, inflammation and aging precipitate depressive behaviour. Biogerontology 2014; 15:439-48. [PMID: 25033986 DOI: 10.1007/s10522-014-9516-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 07/02/2014] [Indexed: 12/19/2022]
Abstract
Major depressive disorder (MDD) is a severe psychiatric illness that is associated with significant morbidity and mortality. Despite advances in the treatment of major depression, one-third of depressed patients fail to respond to conventional antidepressant medication. One pathophysiologic mechanism hypothesized to contribute to treatment resistance in depression is inflammation. Inflammation has been linked to depression by a number of putative mechanisms involving perfusion deficits that can trigger microglial activation and subsequent neuroinflammation in the elderly. However, the pathophysiological mechanisms remain to be further elucidated. This review focusses on recent studies addressing the complex relationships between depression, aging, inflammation and perfusion deficits in the elderly. We expect that a better understanding of neuroinflammatory mechanisms associated with age-related diseases may lead to the discovery of new biomarkers of MDD and development of new therapeutic interventions.
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Affiliation(s)
- Aurel Popa-Wagner
- Department of Psychiatry, University of Medicine Rostock, Gehlsheimerstr. 20, 18147, Rostock, Germany,
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53
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Liu X, Xiao Q, Zhao K, Gao Y. Ghrelin inhibits high glucose-induced PC12 cell apoptosis by regulating TLR4/NF-κB pathway. Inflammation 2014; 36:1286-94. [PMID: 23813326 DOI: 10.1007/s10753-013-9667-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ghrelin has a protective effect on diabetic encephalopathy. To expound the protective mechanism, we investigated the effects of ghrelin on high glucose-induced cell apoptosis and intracellular signaling in cultured PC12, which is a suitable model for studying neuronal cell death. High glucose-induced PC12 apoptosis was significantly inhibited by co-treatment of ghrelin. Sustaining inflammatory response is one of the molecular mechanisms of diabetic encephalopathy and TLR4 signaling has close relationship with inflammatory response. But there is no report about the biologic role of toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) signaling in controlling high glucose-induced PC12 apoptosis by ghrelin. In this study, we found that TLR4/NF-κB pathway was activated by high glucose stimulation in PC12 and significantly alleviated by the co-treatment of ghrelin. From these findings, we made the conclusion that ghrelin could attenuate the symptoms of diabetic encephalopathy, which alleviates inflammatory reaction of diabetic encephalopathy by regulating TLR4/NF-κB pathway.
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Affiliation(s)
- Xiaoyan Liu
- Department of Geriatrics, The First Affiliated Hospital, Chongqing Medical University, No.1 Youyi Road, Yuzhong District, Chongqing, 400016, China
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54
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Soto I, Howell GR. The complex role of neuroinflammation in glaucoma. Cold Spring Harb Perspect Med 2014; 4:cshperspect.a017269. [PMID: 24993677 DOI: 10.1101/cshperspect.a017269] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Glaucoma is a multifactorial neurodegenerative disorder affecting 80 million people worldwide. Loss of retinal ganglion cells and degeneration of their axons in the optic nerve are the major pathological hallmarks. Neuroinflammatory processes, inflammatory processes in the central nervous system, have been identified in human glaucoma and in experimental models of the disease. Furthermore, neuroinflammatory responses occur at early stages of experimental glaucoma, and inhibition of certain proinflammatory pathways appears neuroprotective. Here, we summarize the current understanding of neuroinflammation in the central nervous system, with emphasis on events at the optic nerve head during early stages of glaucoma.
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Affiliation(s)
- Ileana Soto
- The Jackson Laboratory, Bar Harbor, Maine 04609
| | - Gareth R Howell
- The Jackson Laboratory, Bar Harbor, Maine 04609 School of Medicine, Tufts University, Boston, Massachusetts 02111
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55
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The Yin and Yang of innate immunity in stroke. BIOMED RESEARCH INTERNATIONAL 2014; 2014:807978. [PMID: 24877133 PMCID: PMC4021995 DOI: 10.1155/2014/807978] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/15/2014] [Indexed: 11/18/2022]
Abstract
Immune system plays an elementary role in the pathophysiological progress of ischemic stroke. It consists of innate and adaptive immune system. Activated within minutes after ischemic onset, innate immunity is responsible for the elimination of necrotic cells and tissue repair, while it is critically involved in the initiation and amplification of poststroke inflammation that amplifies ischemic damage to the brain tissue. Innate immune response requires days to be fully developed, providing a considerable time window for therapeutic intervention, suggesting prospect of novel immunomodulatory therapies against poststroke inflammation-induced brain injury. However, obstacles still exist and a comprehensive understanding of ischemic stroke and innate immune reaction is essential. In this review, we highlighted the current experimental and clinical data depicting the innate immune response following ischemic stroke, mainly focusing on the recognition of damage-associated molecular patterns, activation and recruitment of innate immune cells, and involvement of various cytokines. In addition, clinical trials targeting innate immunity were also documented regardless of the outcome, stressing the requirements for further investigation.
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56
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Ayton S, Zhang M, Roberts BR, Lam LQ, Lind M, McLean C, Bush AI, Frugier T, Crack PJ, Duce JA. Ceruloplasmin and β-amyloid precursor protein confer neuroprotection in traumatic brain injury and lower neuronal iron. Free Radic Biol Med 2014; 69:331-7. [PMID: 24509156 DOI: 10.1016/j.freeradbiomed.2014.01.041] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/10/2014] [Accepted: 01/31/2014] [Indexed: 10/25/2022]
Abstract
Traumatic brain injury (TBI) is in part complicated by pro-oxidant iron elevation independent of brain hemorrhage. Ceruloplasmin (CP) and β-amyloid protein precursor (APP) are known neuroprotective proteins that reduce oxidative damage through iron regulation. We surveyed iron, CP, and APP in brain tissue from control and TBI-affected patients who were stratified according to time of death following injury. We observed CP and APP induction after TBI accompanying iron accumulation. Elevated APP and CP expression was also observed in a mouse model of focal cortical contusion injury concomitant with iron elevation. To determine if changes in APP or CP were neuroprotective we employed the same TBI model on APP(-/-) and CP(-/-) mice and found that both exhibited exaggerated infarct volume and iron accumulation postinjury. Evidence supports a regulatory role of both proteins in defence against iron-induced oxidative damage after TBI, which presents as a tractable therapeutic target.
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Affiliation(s)
- Scott Ayton
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Moses Zhang
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Blaine R Roberts
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Linh Q Lam
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Monica Lind
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Catriona McLean
- Department of Pathology, and The University of Melbourne, Parkville, VIC 3010, Australia
| | - Ashley I Bush
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health; Department of Pathology, and The University of Melbourne, Parkville, VIC 3010, Australia
| | - Tony Frugier
- Department of Anatomy and Cell Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Peter J Crack
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - James A Duce
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health; School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, North Yorkshire, UK.
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57
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Minter MR, Zhang M, Ates RC, Taylor JM, Crack PJ. Type-1 interferons contribute to oxygen glucose deprivation induced neuro-inflammation in BE(2)M17 human neuroblastoma cells. J Neuroinflammation 2014; 11:43. [PMID: 24602263 PMCID: PMC3995960 DOI: 10.1186/1742-2094-11-43] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/21/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Hypoxic-ischaemic injuries such as stroke and traumatic brain injury exhibit features of a distinct neuro-inflammatory response in the hours and days post-injury. Microglial activation, elevated pro-inflammatory cytokines and macrophage infiltration contribute to core tissue damage and contribute to secondary injury within a region termed the penumbra. Type-1 interferons (IFNs) are a super-family of pleiotropic cytokines that regulate pro-inflammatory gene transcription via the classical Jak/Stat pathway; however their role in hypoxia-ischaemia and central nervous system neuro-inflammation remains unknown. Using an in vitro approach, this study investigated the role of type-1 IFN signalling in an inflammatory setting induced by oxygen glucose deprivation (OGD). METHODS Human BE(2)M17 neuroblastoma cells or cells expressing a type-1 interferon-α receptor 1 (IFNAR1) shRNA or negative control shRNA knockdown construct were subjected to 4.5 h OGD and a time-course reperfusion period (0 to 24 h). Q-PCR was used to evaluate IFNα, IFNβ, IL-1β, IL-6 and TNF-α cytokine expression levels. Phosphorylation of signal transducers and activators of transcription (STAT)-1, STAT-3 and cleavage of caspase-3 was detected by western blot analysis. Post-OGD cellular viability was measured using a MTT assay. RESULTS Elevated IFNα and IFNβ expression was detected during reperfusion post-OGD in parental M17 cells. This correlated with enhanced phosphorylation of STAT-1, a downstream type-1 IFN signalling mediator. Significantly, ablation of type-1 IFN signalling, through IFNAR1 knockdown, reduced IFNα, IFNβ, IL-6 and TNF-α expression in response to OGD. In addition, MTT assay confirmed the IFNAR1 knockdown cells were protected against OGD compared to negative control cells with reduced pro-apoptotic cleaved caspase-3 levels. CONCLUSIONS This study confirms a role for type-1 IFN signalling in the neuro-inflammatory response following OGD in vitro and suggests its modulation through therapeutic blockade of IFNAR1 may be beneficial in reducing hypoxia-induced neuro-inflammation.
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Affiliation(s)
| | | | | | | | - Peter John Crack
- Department of Pharmacology, University of Melbourne, 8th floor, Medical building, Grattan St, Parkville 3010, VIC, Australia.
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58
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Garcia-Bonilla L, Benakis C, Moore J, Iadecola C, Anrather J. Immune mechanisms in cerebral ischemic tolerance. Front Neurosci 2014; 8:44. [PMID: 24624056 PMCID: PMC3940969 DOI: 10.3389/fnins.2014.00044] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/17/2014] [Indexed: 12/21/2022] Open
Abstract
Stressor-induced tolerance is a central mechanism in the response of bacteria, plants, and animals to potentially harmful environmental challenges. This response is characterized by immediate changes in cellular metabolism and by the delayed transcriptional activation or inhibition of genetic programs that are not generally stressor specific (cross-tolerance). These programs are aimed at countering the deleterious effects of the stressor. While induction of this response (preconditioning) can be established at the cellular level, activation of systemic networks is essential for the protection to occur throughout the organs of the body. This is best signified by the phenomenon of remote ischemic preconditioning, whereby application of ischemic stress to one tissue or organ induces ischemic tolerance (IT) in remote organs through humoral, cellular and neural signaling. The immune system is an essential component in cerebral IT acting simultaneously both as mediator and target. This dichotomy is based on the fact that activation of inflammatory pathways is necessary to establish IT and that IT can be, in part, attributed to a subdued immune activation after index ischemia. Here we describe the components of the immune system required for induction of IT and review the mechanisms by which a reprogrammed immune response contributes to the neuroprotection observed after preconditioning. Learning how local and systemic immune factors participate in endogenous neuroprotection could lead to the development of new stroke therapies.
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Affiliation(s)
- Lidia Garcia-Bonilla
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Corinne Benakis
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Jamie Moore
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Costantino Iadecola
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Josef Anrather
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
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59
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Jin Y, Sato K, Tobo A, Mogi C, Tobo M, Murata N, Ishii S, Im DS, Okajima F. Inhibition of interleukin-1β production by extracellular acidification through the TDAG8/cAMP pathway in mouse microglia. J Neurochem 2014; 129:683-95. [PMID: 24447140 DOI: 10.1111/jnc.12661] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 01/16/2014] [Indexed: 12/23/2022]
Abstract
Interleukin-1β (IL-1β) is released from activated microglia and involved in the neurodegeneration of acute and chronic brain disorders, such as stroke and Alzheimer's disease, in which extracellular acidification has been shown to occur. Here, we examined the extracellular acidic pH regulation of IL-1β production, especially focusing on TDAG8, a major proton-sensing G-protein-coupled receptor, in mouse microglia. Extracellular acidification inhibited lipopolysaccharide -induced IL-1β production, which was associated with the inhibition of IL-1β cytoplasmic precursor and mRNA expression. The IL-1β mRNA and protein responses were significantly, though not completely, attenuated in microglia derived from TDAG8-deficient mice compared with those from wild-type mice. The acidic pH also stimulated cellular cAMP accumulation, which was completely inhibited by TDAG8 deficiency. Forskolin and a cAMP derivative, which specifically stimulates protein kinase A (PKA), mimicked the proton actions, and PKA inhibitors reversed the acidic pH-induced IL-1β mRNA expression. The acidic pH-induced inhibitory IL-1β responses were accompanied by the inhibition of extracellular signal-related kinase and c-Jun N-terminal kinase activities. The inhibitory enzyme activities in response to acidic pH were reversed by the PKA inhibitor and TDAG8 deficiency. We conclude that extracellular acidic pH inhibits lipopolysaccharide-induced IL-1β production, at least partly, through the TDAG8/cAMP/PKA pathway, by inhibiting extracellular signal-related kinase and c-Jun N-terminal kinase activities, in mouse microglia.
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Affiliation(s)
- Ye Jin
- Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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60
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Crosstalk Between Insulin and Toll-like Receptor Signaling Pathways in the Central Nervous system. Mol Neurobiol 2014; 50:797-810. [DOI: 10.1007/s12035-013-8631-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 12/25/2013] [Indexed: 01/04/2023]
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Chaitanya GV, Minagar A, Alexander JS. Neuronal and astrocytic interactions modulate brain endothelial properties during metabolic stresses of in vitro cerebral ischemia. Cell Commun Signal 2014; 12:7. [PMID: 24438487 PMCID: PMC3927849 DOI: 10.1186/1478-811x-12-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 11/25/2013] [Indexed: 01/25/2023] Open
Abstract
Neurovascular and gliovascular interactions significantly affect endothelial phenotype. Physiologically, brain endothelium attains several of its properties by its intimate association with neurons and astrocytes. However, during cerebrovascular pathologies such as cerebral ischemia, the uncoupling of neurovascular and gliovascular units can result in several phenotypical changes in brain endothelium. The role of neurovascular and gliovascular uncoupling in modulating brain endothelial properties during cerebral ischemia is not clear. Specifically, the roles of metabolic stresses involved in cerebral ischemia, including aglycemia, hypoxia and combined aglycemia and hypoxia (oxygen glucose deprivation and re-oxygenation, OGDR) in modulating neurovascular and gliovascular interactions are not known. The complex intimate interactions in neurovascular and gliovascular units are highly difficult to recapitulate in vitro. However, in the present study, we used a 3D co-culture model of brain endothelium with neurons and astrocytes in vitro reflecting an intimate neurovascular and gliovascular interactions in vivo. While the cellular signaling interactions in neurovascular and gliovascular units in vivo are much more complex than the 3D co-culture models in vitro, we were still able to observe several important phenotypical changes in brain endothelial properties by metabolically stressed neurons and astrocytes including changes in barrier, lymphocyte adhesive properties, endothelial cell adhesion molecule expression and in vitro angiogenic potential.
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Affiliation(s)
| | | | - Jonathan S Alexander
- Department of Molecular and Cellular Physiology, Louisiana State University Health-Shreveport, Louisiana 71103, USA.
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62
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Scumpia PO, Kelly-Scumpia K, Stevens BR. Alpha-lipoic acid effects on brain glial functions accompanying double-stranded RNA antiviral and inflammatory signaling. Neurochem Int 2013; 64:55-63. [PMID: 24269587 DOI: 10.1016/j.neuint.2013.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 10/23/2013] [Accepted: 11/03/2013] [Indexed: 12/19/2022]
Abstract
Double-stranded RNAs (dsRNA) serve as viral ligands that trigger innate immunity in astrocytes and microglial, as mediated through Toll-like receptor 3 (TLR3) and dsRNA-dependent protein kinase (PKR). Beneficial transient TLR3 and PKR anti-viral signaling can become deleterious when events devolve into inflammation and cytotoxicity. Viral products in the brain cause glial cell dysfunction, and are a putative etiologic factor in neuropsychiatric disorders, notably schizophrenia, bipolar disorder, Parkinson's, and autism spectrum. Alpha-lipoic acid (LA) has been proposed as a possible therapeutic neuroprotectant. The objective of this study was to test our hypothesis that LA can control untoward antiviral mechanisms associated with neural dysfunction. Utilizing rat brain glial cultures (91% astrocytes:9% microglia) treated with PKR- and TLR3-ligand/viral mimetic dsRNA, polyinosinic-polycytidylic acid (polyI:C), we report in vitro glial antiviral signaling and LA reduction of the effects of this signaling. LA blunted the dsRNA-stimulated expression of IFNα/β-inducible genes Mx1, PKR, and TLR3. And in polyI:C treated cells, LA promoted gene expression of rate-limiting steps that benefit healthy neural redox status in glutamateric systems. To this end, LA decreased dsRNA-induced inflammatory signaling by downregulating IL-1β, IL-6, TNFα, iNOS, and CAT2 transcripts. In the presence of polyI:C, LA prevented cultured glial cytotoxicity which was correlated with increased expression of factors known to cooperatively control glutamate/cystine/glutathione redox cycling, namely glutamate uptake transporter GLAST/EAAT1, γ-glutamyl cysteine ligase catalytic and regulatory subunits, and IL-10. Glutamate exporting transporter subunits 4F2hc and xCT were downregulated by LA in dsRNA-stimulated glia. l-Glutamate net uptake was inhibited by dsRNA, and this was relieved by LA. Glutathione synthetase mRNA levels were unchanged by dsRNA or LA. This study demonstrates the protective effects of LA in astroglial/microglial cultures, and suggests the potential for LA efficacy in virus-induced CNS pathologies, with the caveat that antiviral benefits are concomitantly blunted. It is concluded that LA averts key aspects of TLR3- and PKR-provoked glial dysfunction, and provides rationale for exploring LA in whole animal and human clinical studies to blunt or avert neuropsychiatric disorders.
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Affiliation(s)
- Philip O Scumpia
- University of Florida, College of Medicine, Department of Physiology and Functional Genomics, USA
| | - Kindra Kelly-Scumpia
- University of Florida, College of Medicine, Department of Physiology and Functional Genomics, USA
| | - Bruce R Stevens
- University of Florida, College of Medicine, Department of Physiology and Functional Genomics, USA.
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63
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Cox C, Sharp FR. RNA-based blood genomics as an investigative tool and prospective biomarker for ischemic stroke. Neurol Res 2013; 35:457-64. [DOI: 10.1179/1743132813y.0000000212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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64
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The paradox role of regulatory T cells in ischemic stroke. ScientificWorldJournal 2013; 2013:174373. [PMID: 24288462 PMCID: PMC3833121 DOI: 10.1155/2013/174373] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 09/18/2013] [Indexed: 11/18/2022] Open
Abstract
The underlying mechanism of ischemic stroke is not completely known. Regulatory T cells (Tregs), a subset of T cells, play a pivotal role in the pathophysiological process of ischemic stroke. However, there is also controversy over the role of Tregs in stroke. Hence, the function of Tregs in ischemic stroke has triggered a heated discussion recently. In this paper, we reviewed the current lines of evidence to describe the full view of Tregs in stroke. We would like to introduce the basic concepts of Tregs and then discuss their paradox function in ischemic stroke. On one side, Tregs could protect brain against ischemic injury via modulating the inflammation process. On the other side, they exaggerated the insult by causing microvascular dysfunction. They also interfered with the neurological function recovery. In addition, the reasons for this paradox role would be discussed in the review and the prospective of the clinical application of Tregs was also included. In conclusion, Tregs contributed to the outcome of ischemic stroke, while more lines of evidence are needed to understand how Tregs regulate the immune system and influence the outcome of stroke.
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65
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Interleukin-16 polymorphism is associated with an increased risk of ischemic stroke. Mediators Inflamm 2013; 2013:564750. [PMID: 24288444 PMCID: PMC3833071 DOI: 10.1155/2013/564750] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/22/2013] [Indexed: 11/18/2022] Open
Abstract
Clinical and experimental data have demonstrated that inflammation plays fundamental roles in the pathogenesis of ischemic stroke. Interleukin-16 (IL-16) is identified as a proinflammatory cytokine that is a key element in the ischemic cascade after cerebral ischemia. We aimed to examine the relationship between the IL-16 polymorphisms and the risk of ischemic stroke in a Chinese population. A total of 198 patients with ischemic stroke and 236 controls were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing method. We found that the rs11556218TG genotype and G allele of IL-16 were associated with significantly increased risks of ischemic stroke (TG versus TT, adjusted OR = 1.88; 95% CI, 1.15-3.07; G versus T, adjusted OR = 1.54; 95% CI, 1.05-2.27, resp.). However, there were no significant differences in the genotype and allele frequencies of IL-16 rs4778889 T/C and rs4072111 C/T polymorphisms between the two groups, even after stratification analyses by age, gender, and the presence or absence of hypertension, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia. These findings indicate that the IL-16 polymorphism may be related to the etiology of ischemic stroke in the Chinese population.
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66
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Mayer CL, Huber BR, Peskind E. Traumatic brain injury, neuroinflammation, and post-traumatic headaches. Headache 2013; 53:1523-30. [PMID: 24090534 DOI: 10.1111/head.12173] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2013] [Indexed: 12/12/2022]
Abstract
Concussions following head and/or neck injury are common, and although most people with mild injuries recover uneventfully, a subset of individuals develop persistent post-concussive symptoms that often include headaches. Post-traumatic headaches vary in presentation and may progress to become chronic and in some cases debilitating. Little is known about the pathogenesis of post-traumatic headaches, although shared pathophysiology with that of the brain injury is suspected. Following primary injury to brain tissues, inflammation rapidly ensues; while this inflammatory response initially provides a defensive/reparative function, it can persist beyond its beneficial effect, potentially leading to secondary injuries because of alterations in neuronal excitability, axonal integrity, central processing, and other changes. These changes may account for the neurological symptoms often observed after traumatic brain injury, including headaches. This review considers selected aspects of the inflammatory response following traumatic brain injury, with an emphasis on the role of glial cells as mediators of maladaptive post-traumatic inflammation.
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Affiliation(s)
- Cynthia L Mayer
- VA Northwest Network Mental Illness Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
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Müller N, Myint AM, Krause D, Weidinger E, Schwarz MJ. Anti-inflammatory treatment in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2013. [PMID: 23178230 DOI: 10.1016/j.pnpbp.2012.11.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Antipsychotics, which act predominantly as dopamine D2 receptor antagonists, have several shortcomings. The exact pathophysiological mechanism leading to dopaminergic dysfunction in schizophrenia is still unclear, but inflammation has been postulated to be a key player in the pathophysiology of the disorder. A dysfunction in activation of the type 1 immune response seems to be associated with an imbalance in tryptophan/kynurenine metabolism; the degrading enzymes involved in this metabolism are regulated by cytokines. Kynurenic acid (KYNA), an N-methyl-d-aspartate antagonist, was found to be increased in critical regions of the central nervous system (CNS) in schizophrenia, resulting in reduced glutamatergic neurotransmission. The differential activation of microglial cells and astrocytes as functional carriers of the immune system in the CNS may also contribute to this imbalance. The immunological effects of many existing antipsychotics, however, rebalance in part the immune imbalance and overproduction of KYNA. The immunological imbalance results in an inflammatory state combined with increased prostaglandin E(2) production and increased cyclo-oxygenase-2 (COX-2) expression. Growing evidence from clinical studies with COX-2 inhibitors points to favorable effects of anti-inflammatory therapy in schizophrenia, in particular in an early stage of the disorder. Further options for immunomodulating therapies in schizophrenia will be discussed.
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Affiliation(s)
- Norbert Müller
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University, Munich, Germany.
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Hu H, Li Z, Zhu X, Lin R, Lin J, Peng J, Tao J, Chen L. Gua Lou Gui Zhi decoction suppresses LPS-induced activation of the TLR4/NF-κB pathway in BV-2 murine microglial cells. Int J Mol Med 2013; 31:1327-32. [PMID: 23563488 DOI: 10.3892/ijmm.2013.1331] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/19/2013] [Indexed: 11/05/2022] Open
Abstract
Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling-mediated neuroinflammation contributes to secondary brain damage in ischemic stroke; therefore, anti-inflammatory therapy via suppression of the TLR4/NF-κB pathway could be a promising strategy for the treatment of stroke and post-stroke disabilities. Gua Lou Gui Zhi decoction (GLGZD) has long been used in China to clinically treat dysfunction after stroke such as muscular spasticity, but the precise mechanisms are largely unknown. In the present study, we evaluated the anti-inflammatory effect of GLGZD and investigated the underlying molecular mechanisms using lipopolysaccharide (LPS)-stimulated BV-2 microglial cells as an in vitro inflammatory model of neural cells. We found that GLGZD inhibited the inflammatory response in microglial cells as it significantly reduced LPS-induced expression of pro-inflammatory nitric oxide, tumour necrosis factor-α, interleukin (IL)-6 and IL-1β in BV-2 cells, in a dose-dependent manner. In addition, GLGZD treatment significantly decreased the protein expression of TLR4 and myeloid differentiation factor 88, inhibited the phosphorylation of IκB and blocked the nuclear translocation of NF-κB in BV-2 cells, demonstrating its inhibitory effect on the activation of TLR4/NF-κB signaling. Collectively, our findings suggest that inhibition of the inflammatory response via suppression of the TLR4/NF-κB pathway may be one of the mechanisms through which GLGZD ameliorates the damage in ischemic cerebral tissues.
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Affiliation(s)
- Haixia Hu
- Fujian University of Traditional Chinese Medicine, Minhou Shangjie, Fuzhou, People's Republic of China
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69
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Nitric oxide donors as neuroprotective agents after an ischemic stroke-related inflammatory reaction. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:297357. [PMID: 23691263 PMCID: PMC3649699 DOI: 10.1155/2013/297357] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 12/17/2022]
Abstract
Cerebral ischemia initiates a cascade of detrimental events including glutamate-associated excitotoxicity, intracellular calcium accumulation, formation of Reactive oxygen species (ROS), membrane lipid degradation, and DNA damage, which lead to the disruption of cellular homeostasis and structural damage of ischemic brain tissue. Cerebral ischemia also triggers acute inflammation, which exacerbates primary brain damage. Therefore, reducing oxidative stress (OS) and downregulating the inflammatory response are options that merit consideration as potential therapeutic targets for ischemic stroke. Consequently, agents capable of modulating both elements will constitute promising therapeutic solutions because clinically effective neuroprotectants have not yet been discovered and no specific therapy for stroke is available to date. Because of their ability to modulate both oxidative stress and the inflammatory response, much attention has been focused on the role of nitric oxide donors (NOD) as neuroprotective agents in the pathophysiology of cerebral ischemia-reperfusion injury. Given their short therapeutic window, NOD appears to be appropriate for use during neurosurgical procedures involving transient arterial occlusions, or in very early treatment of acute ischemic stroke, and also possibly as complementary treatment for neurodegenerative diseases such as Parkinson or Alzheimer, where oxidative stress is an important promoter of damage. In the present paper, we focus on the role of NOD as possible neuroprotective therapeutic agents for ischemia/reperfusion treatment.
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70
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Lucas K, Maes M. Role of the Toll Like receptor (TLR) radical cycle in chronic inflammation: possible treatments targeting the TLR4 pathway. Mol Neurobiol 2013; 48:190-204. [PMID: 23436141 PMCID: PMC7091222 DOI: 10.1007/s12035-013-8425-7] [Citation(s) in RCA: 334] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 02/05/2013] [Indexed: 12/11/2022]
Abstract
Activation of the Toll-like receptor 4 (TLR4) complex, a receptor of the innate immune system, may underpin the pathophysiology of many human diseases, including asthma, cardiovascular disorder, diabetes, obesity, metabolic syndrome, autoimmune disorders, neuroinflammatory disorders, schizophrenia, bipolar disorder, autism, clinical depression, chronic fatigue syndrome, alcohol abuse, and toluene inhalation. TLRs are pattern recognition receptors that recognize damage-associated molecular patterns and pathogen-associated molecular patterns, including lipopolysaccharide (LPS) from gram-negative bacteria. Here we focus on the environmental factors, which are known to trigger TLR4, e.g., ozone, atmosphere particulate matter, long-lived reactive oxygen intermediate, pentachlorophenol, ionizing radiation, and toluene. Activation of the TLR4 pathways may cause chronic inflammation and increased production of reactive oxygen and nitrogen species (ROS/RNS) and oxidative and nitrosative stress and therefore TLR-related diseases. This implies that drugs or substances that modify these pathways may prevent or improve the abovementioned diseases. Here we review some of the most promising drugs and agents that have the potential to attenuate TLR-mediated inflammation, e.g., anti-LPS strategies that aim to neutralize LPS (synthetic anti-LPS peptides and recombinant factor C) and TLR4/MyD88 antagonists, including eritoran, CyP, EM-163, epigallocatechin-3-gallate, 6-shogaol, cinnamon extract, N-acetylcysteine, melatonin, and molecular hydrogen. The authors posit that activation of the TLR radical (ROS/RNS) cycle is a common pathway underpinning many "civilization" disorders and that targeting the TLR radical cycle may be an effective method to treat many inflammatory disorders.
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Affiliation(s)
- Kurt Lucas
- Sportzenkoppel 54, 22359, Hamburg, Germany
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71
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Ju C, Hwang S, Cho GS, Kondaji G, Song S, Prather PL, Choi Y, Kim WK. Differential anti-ischemic efficacy and therapeutic time window of trans- and cis-hinokiresinols: stereo-specific antioxidant and anti-inflammatory activities. Neuropharmacology 2013; 67:465-75. [PMID: 23287539 DOI: 10.1016/j.neuropharm.2012.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/16/2012] [Accepted: 12/17/2012] [Indexed: 11/30/2022]
Abstract
During cerebral ischemia, neurons are injured by various mechanisms including excitotoxicity, oxidative stress, and inflammatory responses. Thus, pharmacological manipulation of multiple cytotoxic pathways has been pursued for the treatment of ischemic injury. Cis-hinokiresinol, a naturally occurring phenylpropanoid, was previously reported to possess anti-oxidant, anti-inflammatory and estrogen-like activities. In the present study, we investigated anti-ischemic effects of trans- and cis-hinokiresinols using in vitro as well as in vivo experimental models. The ORAC and DPPH assays showed that two isomers had similar free radical scavenging activities. However, only trans-hinokiresinol significantly decreased neuronal injury in cultured cortical neurons exposed to oxygen-glucose deprivation (75 min) followed by re-oxygenation (9 h). The differential neuroprotective effect could be due to the stereo-specific augmentation of Cu/Zn-SOD activity by trans-hinokiresinol, when compared with cis-hinokiresinol. Similarly, in rats subjected to transient middle cerebral artery occlusion (1.5 h) followed by 24-h reperfusion, pre-ischemic treatment with trans-hinokiresinol, but not with cis-isomer, reduced cerebral infarct volume. Interestingly, however, post-ischemic treatment with both hinokiresinols (2 and 7 h after onset of ischemia) significantly reduced cerebral infarct. When administered after onset of ischemia, trans-hinokiresinol, but not its cis-isomer reduced nitrotyrosine immunoreactivity in ischemic regions. In contrast, both hinokiresinols suppressed neutrophil infiltration and IL-1β release to a similar extent. The observed differential anti-oxidant, but comparable anti-inflammatory, activities may explain the stereo-specific anti-ischemic activities and different therapeutic time windows of the hinokiresinols examined. More detailed delineation of the anti-ischemic mechanism(s) of hinokiresinols may provide a better strategy for development of efficacious regimens for cerebral ischemic stroke.
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Affiliation(s)
- Chung Ju
- Department of Neuroscience, College of Medicine, Korea University, Anamdong-5-ga, Seongbuk-gu, Seoul 136-705, Republic of Korea
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72
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Ronaldson PT, Davis TP. Blood-brain barrier integrity and glial support: mechanisms that can be targeted for novel therapeutic approaches in stroke. Curr Pharm Des 2012; 18:3624-44. [PMID: 22574987 DOI: 10.2174/138161212802002625] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 12/31/2022]
Abstract
The blood-brain barrier (BBB) is a critical regulator of brain homeostasis. Additionally, the BBB is the most significant obstacle to effective CNS drug delivery. It possesses specific charcteristics (i.e., tight junction protein complexes, influx and efflux transporters) that control permeation of circulating solutes including therapeutic agents. In order to form this "barrier," brain microvascular endothelial cells require support of adjacent astrocytes and microglia. This intricate relationship also occurs between endothelial cells and other cell types and structures of the CNS (i.e., pericytes, neurons, extracellular matrix), which implies existence of a "neurovascular unit." Ischemic stroke can disrupt the neurovascular unit at both the structural and functional level, which leads to an increase in leak across the BBB. Recent studies have identified several pathophysiological mechanisms (i.e., oxidative stress, activation of cytokine-mediated intracellular signaling systems) that mediate changes in the neurovascular unit during ischemic stroke. This review summarizes current knowledge in this area and emphasizes pathways (i.e., oxidative stress, cytokine-mediated intracellular signaling, glial-expressed receptors/targets) that can be manipulated pharmacologically for i) preservation of BBB and glial integrity during ischemic stroke and ii) control of drug permeation and/or transport across the BBB. Targeting these pathways present a novel opportunity for optimization of CNS delivery of therapeutics in the setting of ischemic stroke.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Avenue, P.O. Box 245050, Tucson, AZ 85724-5050, USA.
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73
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Nagel S, Hadley G, Pfleger K, Grond-Ginsbach C, Buchan AM, Wagner S, Papadakis M. Suppression of the inflammatory response by diphenyleneiodonium after transient focal cerebral ischemia. J Neurochem 2012; 123 Suppl 2:98-107. [PMID: 23050647 DOI: 10.1111/j.1471-4159.2012.07948.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diphenyleneiodonium (DPI), a NADPH oxidase inhibitor, reduces production of reactive oxygen species (ROS) and confers neuroprotection to focal cerebral ischemia. Our objective was to investigate whether the neuroprotective action of DPI extends to averting the immune response. DPI-induced gene changes were analyzed by microarray analysis from rat brains subjected to 90 min of middle cerebral artery occlusion, treated with NaCl (ischemia), dimethylsulfoxide (DMSO), or DMSO and DPI (DPI), and reperfused for 48 h. The genomic expression profile was compared between groups using ingenuity pathway analysis at the pathway and network level. DPI selectively up-regulated 23 genes and down-regulated 75 genes more than twofold compared with both DMSO and ischemia. It significantly suppressed inducible nitric oxide synthase signaling and increased the expression of methionine adenosyltransferasesynthetase 2A and adenosylmethionine decarboxylase 1 genes, which are involved in increasing the production of the antioxidant glutathione. The most significantly affected gene network comprised genes implicated in the inflammatory response with an expression change indicating an overall suppression. Both integrin- and interleukin-17A-signaling pathways were also significantly associated and suppressed. In conclusion, the neuroprotective effects of DPI are mediated not only by suppressing ischemia-triggered oxidative stress but also by limiting leukocyte migration and infiltration.
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Affiliation(s)
- Simon Nagel
- Department of Neurology, University of Heidelberg, Heidelberg, Germany
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74
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Park HY, Jun CD, Jeon SJ, Choi SS, Kim HR, Choi DB, Kwak S, Lee HS, Cheong JS, So HS, Lee YJ, Park DS. Serum YKL-40 levels correlate with infarct volume, stroke severity, and functional outcome in acute ischemic stroke patients. PLoS One 2012; 7:e51722. [PMID: 23272150 PMCID: PMC3522716 DOI: 10.1371/journal.pone.0051722] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/05/2012] [Indexed: 12/22/2022] Open
Abstract
Background and Purpose YKL-40 is associated with various neurological disorders. However, circulatory YKL-40 levels early after onset of acute ischemic stroke (AIS) have not been systematically assessed. We aimed to identify the temporal changes and clinical usefulness of measuring serum YKL-40 immediately following AIS. Methods Serum YKL-40 and C-reactive protein (CRP) levels were monitored over time in AIS patients (n = 105) and compared with those of stroke-free controls (n = 34). Infarct volume and stroke severity (National Institutes of Health Stroke Scale; NIHSS) were measured within 48 hours of symptom onset, and functional outcome (modified Rankin Scale; mRS) was measured 3 months after AIS. Results Within 12 hours of symptom onset, levels of YKL-40 (251 vs. 41 ng/mL) and CRP (1.50 vs. 0.96 µg/mL) were elevated in AIS patients compared to controls. The power of YKL-40 for discriminating AIS patients from controls was superior to that of CRP (area under the curve 0.84 vs. 0.64) and YKL-40 (r = 0.26, P<0.001) but not CRP levels were correlated with mRS. On day 2 of admission (D2), YKL-40 levels correlated with infarct volume and NIHSS. High YKL-40 levels predicted poor functional outcome (odds ratio 5.73, P = 0.03). YKL-40 levels peaked on D2 and declined on D3, whereas CRP levels were highest on D3. Conclusions Our results demonstrate serial changes in serum YKL-40 levels immediately following AIS and provide the first evidence that it is a valid indicator of AIS extent and an early predictor of functional outcome.
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Affiliation(s)
- Hyun Young Park
- Department of Neurology, School of Medicine, Wonkwang University, Iksan, Korea
| | | | - Se-Jeong Jeon
- Department of Radiology, School of Medicine, Wonkwang University, Iksan, Korea
| | - See-Sung Choi
- Department of Radiology, School of Medicine, Wonkwang University, Iksan, Korea
| | - Hak-Ryul Kim
- Department of Internal Medicine, School of Medicine, Wonkwang University, Iksan, Korea
| | - Dan-Bee Choi
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan, Korea
| | - Seongae Kwak
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan, Korea
| | - Hak-Seung Lee
- Department of Neurology, School of Medicine, Wonkwang University, Iksan, Korea
| | - Jin Sung Cheong
- Department of Radiology, School of Medicine, Wonkwang University, Iksan, Korea
| | - Hong-Seob So
- Department of Microbiology, School of Medicine, Wonkwang University, Iksan, Korea
- Center for Metabolic Function Regulation, Institute of Wonkwang Medical Science, and Institute of Wonkwang Clinical Medicine, School of Medicine, Wonkwang University, Iksan, Korea
| | - Young-Jin Lee
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan, Korea
| | - Do-Sim Park
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan, Korea
- Center for Metabolic Function Regulation, Institute of Wonkwang Medical Science, and Institute of Wonkwang Clinical Medicine, School of Medicine, Wonkwang University, Iksan, Korea
- * E-mail:
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75
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Bigler ED, Maxwell WL. Neuropathology of mild traumatic brain injury: relationship to neuroimaging findings. Brain Imaging Behav 2012; 6:108-36. [PMID: 22434552 DOI: 10.1007/s11682-011-9145-0] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neuroimaging identified abnormalities associated with traumatic brain injury (TBI) are but gross indicators that reflect underlying trauma-induced neuropathology at the cellular level. This review examines how cellular pathology relates to neuroimaging findings with the objective of more closely relating how neuroimaging findings reveal underlying neuropathology. Throughout this review an attempt will be made to relate what is directly known from post-mortem microscopic and gross anatomical studies of TBI of all severity levels to the types of lesions and abnormalities observed in contemporary neuroimaging of TBI, with an emphasis on mild traumatic brain injury (mTBI). However, it is impossible to discuss the neuropathology of mTBI without discussing what occurs with more severe injury and viewing pathological changes on some continuum from the mildest to the most severe. Historical milestones in understanding the neuropathology of mTBI are reviewed along with implications for future directions in the examination of neuroimaging and neuropathological correlates of TBI.
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Affiliation(s)
- Erin D Bigler
- Department of Psychology, Brigham Young University, Provo, UT, USA.
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76
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Bellavance MA, Rivest S. The neuroendocrine control of the innate immune system in health and brain diseases. Immunol Rev 2012; 248:36-55. [PMID: 22725953 DOI: 10.1111/j.1600-065x.2012.01129.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The innate immune reaction takes place in the brain during immunogenic challenges, injury, and disease. Such a response is highly regulated by numerous anti-inflammatory mechanisms that may directly affect the ultimate consequences of such a reaction within the cerebral environment. The neuroendocrine control of this innate immune system by glucocorticoids is critical for the delicate balance between cell survival and damage in the presence of inflammatory mediators. Glucocorticoids play key roles in regulating the expression of inflammatory genes, and they also have the ability to modulate numerous functions that may ultimately lead to brain damage or repair after injury. Here we review these mechanisms and discuss data supporting both neuroprotective and detrimental roles of the neuroendocrine control of innate immunity.
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Affiliation(s)
- Marc-André Bellavance
- Laboratory of Endocrinology and Genomics, CHUQ Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, Québec, Canada
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77
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Abstract
Since the initial description of apoptosis, a number of different forms of cell death have been described. In this review we will focus on classic caspase-dependent apoptosis and its variations that contribute to diseases. Over fifty years of research have clarified molecular mechanisms involved in apoptotic signaling as well and shown that alterations of these pathways lead to human diseases. Indeed both reduced and increased apoptosis can result in pathology. More recently these findings have led to the development of therapeutic approaches based on regulation of apoptosis, some of which are in clinical trials or have entered medical practice.
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Affiliation(s)
- Bartolo Favaloro
- Dipartimento di Scienze Biomediche, Universita' "G. d'Annunzio" Chieti-Pescara, Italy
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78
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Leow-Dyke S, Allen C, Denes A, Nilsson O, Maysami S, Bowie AG, Rothwell NJ, Pinteaux E. Neuronal Toll-like receptor 4 signaling induces brain endothelial activation and neutrophil transmigration in vitro. J Neuroinflammation 2012; 9:230. [PMID: 23034047 PMCID: PMC3481358 DOI: 10.1186/1742-2094-9-230] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 09/13/2012] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The innate immune response in the brain is initiated by pathogen-associated molecular patterns (PAMPS) or danger-associated molecular patterns (DAMPS) produced in response to central nervous system (CNS) infection or injury. These molecules activate members of the Toll-like receptor (TLR) family, of which TLR4 is the receptor for bacterial lipopolysaccharide (LPS). Although neurons have been reported to express TLR4, the function of TLR4 activation in neurons remains unknown. METHODS TLR4 mRNA expression in primary mouse glial and neuronal cultures was assessed by RT-PCR. Mouse mixed glial, neuronal or endothelial cell cultures were treated with LPS in the absence or the presence of a TLR4 specific antagonist (VIPER) or a specific JNK inhibitor (SP600125). Expression of inflammatory mediators was assayed by cytometric bead array (CBA) and ELISA. Activation of extracellular-signal regulated kinase 1/2 (ERK1/2), p38, c-Jun-N-terminal kinase (JNK) and c-Jun was assessed by Western blot. The effect of conditioned media of untreated- versus LPS-treated glial or neuronal cultures on endothelial activation was assessed by neutrophil transmigration assay, and immunocytochemistry and ELISA were used to measure expression of intercellular cell adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1). RESULTS LPS induces strong release of the chemokines RANTES and CXCL1 (KC), tumor necrosis factor-α (TNFα) and IL-6 in primary mouse neuronal cultures. In contrast, LPS induced release of IL-1α, IL-1β and granulocyte-colony stimulating factor (G-CSF) in mixed glial, but not in neuronal cultures. LPS-induced neuronal KC expression and release were completely blocked by VIPER. In glial cultures, LPS induced activation of ERK1/2, p38 and JNK. In contrast, in neuronal cultures, LPS activated JNK but not ERK1/2 or p38, and the specific JNK inhibitor SP600125 significantly blocked LPS-induced KC expression and release. Finally, conditioned medium of LPS-treated neuronal cultures induced strong expression of ICAM-1 and VCAM-1 on endothelial cells, and induced infiltration of neutrophils across the endothelial monolayer, which was inhibited by VIPER. CONCLUSION These data demonstrate for the first time that neurons can play a role as key sensors of infection to initiate CNS inflammation.
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Affiliation(s)
- Sophie Leow-Dyke
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
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79
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Biphasic activation of nuclear factor-kappa B in experimental models of subarachnoid hemorrhage in vivo and in vitro. Mediators Inflamm 2012; 2012:786242. [PMID: 23049172 PMCID: PMC3461645 DOI: 10.1155/2012/786242] [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: 07/12/2012] [Accepted: 08/21/2012] [Indexed: 12/19/2022] Open
Abstract
It has been proven that nuclear factor-kappa B (NF-κB) is activated as a well-known transcription factor after subarachnoid hemorrhage (SAH). However, the panoramic view of NF-κB activity after SAH remained obscure. Cultured neurons were signed into control group and six hemoglobin- (Hb-) incubated groups. One-hemorrhage rabbit SAH model was produced, and the rabbits were divided randomly into one control group and five SAH groups. NF-κB activity was detected by electrophoretic mobility shift assay (EMSA) and immunohistochemistry. Real-time polymerase chain reaction (PCR) was performed to assess the downstream genes of NF-κB. NeuN immunofluorescence and lactate dehydrogenase (LDH) quantification were used to estimate the neuron injury. Double drastically elevated NF-κB activity peaks were detected in rabbit brains and cultured neurons. The downstream gene expressions showed an accordant phase peaks. NeuN-positive cells decreased significantly in day 3 and day 10 groups. LDH leakage exhibited a significant increase in Hb-incubated groups, but no significant difference was found between the Hb incubated groups. These results suggested that biphasic increasing of NF-κB activity was induced after SAH, and the early NF-κB activity peak indicated the injury role on neurons; however, the late peak might not be involved in the deteriorated effect on neurons.
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80
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Müller N, Wagner JK, Krause D, Weidinger E, Wildenauer A, Obermeier M, Dehning S, Gruber R, Schwarz MJ. Impaired monocyte activation in schizophrenia. Psychiatry Res 2012; 198:341-6. [PMID: 22429483 DOI: 10.1016/j.psychres.2011.12.049] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/11/2011] [Accepted: 12/31/2011] [Indexed: 01/31/2023]
Abstract
An inflammatory process is hypothesized in schizophrenia. Innate immunity, in particular the monocyte/macrophage system, has rarely been studied in this disorder, although alterations in microglia indicate a role for this system. Increased monocyte numbers have repeatedly been described. Toll-like receptors (TLRs) mediate the activation of monocytes. We studied the expression of the toll-like receptors TLR-2, TLR-3 and TLR-4 on CD14(+) monocytes in 31 schizophrenia patients and 31 sex- and age-matched healthy controls. Blood samples were taken and stimulated with either lipopolysaccharides (LPS), to mimic a bacterial infection, or polyI:C, to mimic a viral infection. Moreover, the intracellular concentration of interleukin-1ß (IL-1ß) in CD33(+) monocytes was estimated before and after stimulation. The intracellular concentrations of IL-1ß and the TLR surface markers were analyzed by flow cytometry. Receptor expression of TLR-3 and TLR-4, but not of TLR-2, was significantly higher in the schizophrenia patients. After stimulation, patients showed less increase in the expression of TLR-3 and TLR-4 than controls did. The IL-1ß concentration was significantly lower in patients both before and after stimulation with polyI:C, and there was a trend towards a lower concentration after LPS stimulation. The higher expression of TLR-3 and TLR-4 receptors might compensate for a functional deficit, and the lower intracellular concentrations of IL-1ß might reflect the blunted monocytic function in schizophrenia. The immunological dysfunctions might be associated with a poor clearance of pathogens in schizophrenia, which in turn could lead to a low-grade inflammatory process.
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Affiliation(s)
- Norbert Müller
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilian University, Nussbaumstr. 7, 80336 Munich, Germany.
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81
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Gomes-Leal W. Microglial physiopathology: how to explain the dual role of microglia after acute neural disorders? Brain Behav 2012; 2:345-56. [PMID: 22741103 PMCID: PMC3381634 DOI: 10.1002/brb3.51] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 12/21/2022] Open
Abstract
Microglia are the resident macrophages of the central nervous system (CNS). In physiological conditions, resting microglia maintain tissue integrity by scanning the entire CNS parenchyma through stochastic and complex movements of their long processes to identify minor tissue alterations. In pathological conditions, over-activated microglia contribute to neuronal damage by releasing harmful substances, including inflammatory cytokines, reactive oxygen species, and proteinases, but they can provide tissue repair by releasing anti-inflammatory cytokines and neurotrophic factors. The reasons for this apparent paradox are unknown. In this paper, we first review the physiological role as well as both detrimental and beneficial actions of microglial during acute CNS disorders. Further, we discuss the possible reasons for this microglial dual role following CNS insults, considering that the final microglial phenotype is a direct consequence of both noxious and beneficial stimuli released into the extracellular space during the pathological insult. The nature of these micro-glial ligands is unknown, but we hypothesize that harmful and beneficial stimuli may be preferentially located at specific anatomical niches along the pathological environment triggering both beneficial and deleterious actions of these glial cells. According to this notion, there are no natural populations of detrimental microglia, but is the pathological environment that determines the final microglial phenotype.
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Affiliation(s)
- Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará-Brazil Belém-Pará 66075-900, Brazil
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82
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Berard JL, Zarruk JG, Arbour N, Prat A, Yong VW, Jacques FH, Akira S, David S. Lipocalin 2 is a novel immune mediator of experimental autoimmune encephalomyelitis pathogenesis and is modulated in multiple sclerosis. Glia 2012; 60:1145-59. [PMID: 22499213 DOI: 10.1002/glia.22342] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/20/2012] [Indexed: 12/23/2022]
Abstract
Experimental autoimmune encephalomyelitis (EAE) is a widely used animal model of multiple sclerosis (MS), an inflammatory, demyelinating disease of the central nervous system (CNS). EAE pathogenesis involves various cell types, cytokines, chemokines, and adhesion molecules. Given the complexity of the inflammatory response in EAE, it is likely that many immune mediators still remain to be discovered. To identify novel immune mediators of EAE pathogenesis, we performed an Affymetrix gene array screen on the spinal cords of mice at the onset stage of disease. This screening identified the gene encoding lipocalin 2 (Lcn2) as being significantly upregulated. Lcn2 is a multi-functional protein that plays a role in glial activation, matrix metalloproteinase (MMP) stabilization, and cellular iron flux. As many of these processes have been implicated in EAE, we characterized the expression and role of Lcn2 in this disease in C57BL/6 mice. We show that Lcn2 is significantly upregulated in the spinal cord throughout EAE and is expressed predominantly by monocytes and reactive astrocytes. The Lcn2 receptor, 24p3R, is also expressed on monocytes, macrophages/microglia, and astrocytes in EAE. In addition, we show that EAE severity is increased in Lcn2(-/-) mice as compared with wild-type controls. Finally, we demonstrate that elevated levels of Lcn2 are detected in the plasma and cerebrospinal fluid (CSF) in MS and in immune cells in CNS lesions in MS tissue sections. These data indicate that Lcn2 is a modulator of EAE pathogenesis and suggest that it may also play a role in MS.
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Affiliation(s)
- Jennifer L Berard
- Center for Research in Neuroscience, The Research Institute of The McGill University Health Center, Montreal, Quebec, Canada
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83
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Ransohoff RM, Brown MA. Innate immunity in the central nervous system. J Clin Invest 2012; 122:1164-71. [PMID: 22466658 DOI: 10.1172/jci58644] [Citation(s) in RCA: 699] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Immune responses in the CNS are common, despite its perception as a site of immune privilege. These responses can be mediated by resident microglia and astrocytes, which are innate immune cells without direct counterparts in the periphery. Furthermore, CNS immune reactions often take place in virtual isolation from the innate/adaptive immune interplay that characterizes peripheral immunity. However, microglia and astrocytes also engage in significant cross-talk with CNS-infiltrating T cells and other components of the innate immune system. Here we review the cellular and molecular basis of innate immunity in the CNS and discuss what is known about how outcomes of these interactions can lead to resolution of infection, neurodegeneration, or neural repair depending on the context.
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Affiliation(s)
- Richard M Ransohoff
- Neuroinflammation Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
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84
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Khansari PS, Sperlagh B. Inflammation in neurological and psychiatric diseases. Inflammopharmacology 2012; 20:103-7. [PMID: 22361843 DOI: 10.1007/s10787-012-0124-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 02/02/2012] [Indexed: 01/09/2023]
Abstract
In recent years, compelling evidence suggests that inflammation plays a critical role in the pathology of a vast number of neurological diseases such as stroke, Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis as well as neuropsychiatric diseases such as major depression and schizophrenia. Despite emerging evidence in human and animal models alike, modulating inflammatory responses have yet to be proven as an effective treatment to prevent or delay the progression of these diseases. The primary focus of this special edition is to highlight some of our current findings on the complexities of targeting neuroinflammation as a novel therapy, and its role in neurological and psychiatric disorders.
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Affiliation(s)
- Parto S Khansari
- California Northstate University College of Pharmacy, Rancho Cordova, CA, USA.
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85
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Chen CC, Hung TH, Wang YH, Lin CW, Wang PY, Lee CY, Chen SF. Wogonin improves histological and functional outcomes, and reduces activation of TLR4/NF-κB signaling after experimental traumatic brain injury. PLoS One 2012; 7:e30294. [PMID: 22272328 PMCID: PMC3260265 DOI: 10.1371/journal.pone.0030294] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 12/13/2011] [Indexed: 11/18/2022] Open
Abstract
Background Traumatic brain injury (TBI) initiates a neuroinflammatory cascade that contributes to neuronal damage and behavioral impairment. This study was undertaken to investigate the effects of wogonin, a flavonoid with potent anti-inflammatory properties, on functional and histological outcomes, brain edema, and toll-like receptor 4 (TLR4)- and nuclear factor kappa B (NF-κB)-related signaling pathways in mice following TBI. Methodology/Principal Findings Mice subjected to controlled cortical impact injury were injected with wogonin (20, 40, or 50 mg·kg−1) or vehicle 10 min after injury. Behavioral studies, histology analysis, and measurement of blood-brain barrier (BBB) permeability and brain water content were carried out to assess the effects of wogonin. Levels of TLR4/NF-κB-related inflammatory mediators were also examined. Treatment with 40 mg·kg−1 wogonin significantly improved functional recovery and reduced contusion volumes up to post-injury day 28. Wogonin also significantly reduced neuronal death, BBB permeability, and brain edema beginning at day 1. These changes were associated with a marked reduction in leukocyte infiltration, microglial activation, TLR4 expression, NF-κB translocation to nucleus and its DNA binding activity, matrix metalloproteinase-9 activity, and expression of inflammatory mediators, including interleukin-1β, interleukin-6, macrophage inflammatory protein-2, and cyclooxygenase-2. Conclusions/Significance Our results show that post-injury wogonin treatment improved long-term functional and histological outcomes, reduced brain edema, and attenuated the TLR4/NF-κB-mediated inflammatory response in mouse TBI. The neuroprotective effects of wogonin may be related to modulation of the TLR4/NF-κB signaling pathway.
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Affiliation(s)
- Chien-Cheng Chen
- Department of Physical Medicine and Rehabilitation, Cheng Hsin General Hospital, Taipei, Taiwan, Republic of China
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86
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Abstract
Although there is no doubt that the dopaminergic neurotransmission is strongly involved in the pathophysiology of schizophrenia, the exact mechanism leading to dopaminergic dysfunction is still unclear. A disbalance in the immune response associated with a slight inflammatory process of the central nervous system (CNS) has been postulated. Such a mechanism is the basis for the "mild encephalitis" concept. A dysfunction in the activation of the type-1 immune response seems to be associated with decreased activity of the key enzyme of the tryptophan/kynurenine metabolism, indoleamine 2,3-dioxygenase (IDO). Theoretically, a decreased activity of IDO results in the increased production of kynurenic acid, an N-methyl-D-aspartate antagonist in the CNS, and a reduced glutamatergic neurotransmission in schizophrenia. Accordingly, in animal models of schizophrenia, increased levels of kynurenic acid in critical regions of the CNS were described, although studies of peripheral blood levels of kynurenic acid in schizophrenic patients showed controversial results. The immunological effects of a lot of existing antipsychotics, however, rebalance in part the immune imbalance and the overweight of the production of kynurenic acid. The inflammatory state in schizophrenia is associated with increased prostaglandin E(2) production and increased cyclooxygenase-2 (COX-2) expression. Growing evidence from clinical studies with COX-2 inhibitors points to favorable effects of anti-inflammatory therapy in schizophrenia, in particular in an early stage of the disorder. Further options for immunomodulating therapies in schizophrenia will be discussed.
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87
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Galic MA, Riazi K, Pittman QJ. Cytokines and brain excitability. Front Neuroendocrinol 2012; 33:116-25. [PMID: 22214786 PMCID: PMC3547977 DOI: 10.1016/j.yfrne.2011.12.002] [Citation(s) in RCA: 286] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/07/2011] [Accepted: 12/15/2011] [Indexed: 01/21/2023]
Abstract
Cytokines are molecules secreted by peripheral immune cells, microglia, astrocytes and neurons in the central nervous system. Peripheral or central inflammation is characterized by an upregulation of cytokines and their receptors in the brain. Emerging evidence indicates that pro-inflammatory cytokines modulate brain excitability. Findings from both the clinical literature and from in vivo and in vitro laboratory studies suggest that cytokines can increase seizure susceptibility and may be involved in epileptogenesis. Cellular mechanisms that underlie these effects include upregulation of excitatory glutamatergic transmission and downregulation of inhibitory GABAergic transmission.
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Affiliation(s)
- Michael A Galic
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Health Sciences Centre, 3330 Hospital Dr. NW, Calgary, Alberta, Canada T2N 4N1
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88
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Colak G, Johnson GVW. Complete transglutaminase 2 ablation results in reduced stroke volumes and astrocytes that exhibit increased survival in response to ischemia. Neurobiol Dis 2011; 45:1042-50. [PMID: 22198379 DOI: 10.1016/j.nbd.2011.12.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/02/2011] [Accepted: 12/06/2011] [Indexed: 02/09/2023] Open
Abstract
Transglutaminase 2 (TG2) is a very multifunctional protein that is ubiquitously expressed in the body. It is a Ca(2+)-dependent transamidating enzyme, a GTPase, as well as a scaffolding protein. TG2 is the predominant form of transglutaminase expressed in the mammalian nervous system. Previously, it was shown that TG2 can affect both cell death and cell survival mechanisms depending on the cell type and the stressor. In the case of ischemic stress, TG2 was previously shown to play a protective role in the models used. For example in hTG2 transgenic mice, where TG2 is overexpressed only in neurons, middle cerebral artery ligation (MCAL) resulted in smaller infarct volumes compared to wild type mice. In this study TG2 knock out mice were used to determine how endogenous TG2 affected stroke volumes. Intriguingly, infarct volumes in TG2 knock out mice were significantly smaller compared to wild type mice. As expected, primary neurons isolated from TG2 knock out mice showed decreased viability in response to oxygen-glucose deprivation. However, primary astrocytes that were isolated from TG2 knock out mice were resistant to oxygen-glucose deprivation in situ. Both wild type and knock out neurons were protected against oxygen glucose deprivation when they were co-cultured with astrocytes from TG2 knockout mice. Therefore, the decreased stroke volumes observed in TG2 knock out mice after MCAL, can be correlated with the protective effects of TG2 knock out in astrocytes in response to oxygen glucose deprivation in situ. These findings suggest that neuron-astrocyte crosstalk plays a significant role in mediating ischemic cell death and that TG2 differentially impacts cell survival depending on cell context.
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Affiliation(s)
- Gozde Colak
- Department of Pharmacology and Physiology, 601 Elmwood Avenue, Box 711, University of Rochester, Rochester, NY 14642, USA
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89
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The role of cell type-specific responses in IFN-β therapy of multiple sclerosis. Proc Natl Acad Sci U S A 2011; 108:19689-94. [PMID: 22106296 DOI: 10.1073/pnas.1117347108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The mechanism of IFN-β therapy in relapsing-remitting multiple sclerosis (RRMS) is not well understood, but induction of apoptosis in specific leukocyte subsets is likely to be important. Enhanced expression of TNFSF10 or TNF-related apoptosis-inducing ligand (TRAIL) mRNA in unseparated leukocytes has been put forward as a therapeutic response marker, but it is unclear which leukocyte subsets express TRAIL. We investigated the basis of TRAIL expression in response to IFN-β by studying activation of STATs 1, 3, and 5, p38 MAPK, and NF-κB in different leukocyte subsets of patients with RRMS. Monocytes, B cells, and T cells showed substantial differences in the activation of p38 and the STATs in response to i.m. injection of IFN-β1a or stimulation in vitro. Induction of cell-surface TRAIL, analyzed in nine leukocyte subsets, was observed only on monocytes and granulocytes and correlated with the activation of p38 and/or NF-κB in these subsets only, in agreement with previous work in fibroblasts showing that the induction of TRAIL in response to IFN-β depends on the activation of p38 and NF-κB as well as STATs 1 and 2. We propose that, in myeloid cells, the differential activation of p38 and NF-κB and induction of TRAIL, which sensitizes cells to apoptosis, can help to explain differences in responsiveness to IFN-β therapy among patients with RRMS and, furthermore, that such differential patterns of activation and expression may also be important in understanding the therapeutic responses to IFN-α/β in hepatitis and cancer.
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90
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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: 370] [Impact Index Per Article: 28.5] [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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91
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Yoo KY, Yoo DY, Hwang IK, Park JH, Lee CH, Choi JH, Kwon SH, Her S, Lee YL, Won MH. Time-course alterations of Toll-like receptor 4 and NF-κB p65, and their co-expression in the gerbil hippocampal CA1 region after transient cerebral ischemia. Neurochem Res 2011; 36:2417-26. [PMID: 21842272 DOI: 10.1007/s11064-011-0569-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 07/28/2011] [Accepted: 08/02/2011] [Indexed: 12/24/2022]
Abstract
Innate immune system is very important to modulate the host defense against a large variety of pathogens. Toll-like receptors (TLRs) play a key role in controlling innate immune response. Among TLRs, TLR4 is a specific receptor for lipopolysaccharide and associated with the release of pro-inflammatory cytokines. In the present study, we investigated ischemia-related changes of TLR4 immunoreactivity and its protein level, and nuclear factor κB (NF-κB) p65 immunoreactivity regarding inflammatory responses in the hippocampal CA1 region after 5 min of transient cerebral ischemia to identify the correlation between transient ischemia and inflammation. In the sham-operated group, TLR4 immunoreactivity was easily detected in pyramidal neurons of the hippocampal CA1 region (CA1). TLR4 immunoreactivity in pyramidal neurons was distinctively decreased after ischemia/reperfusion (I/R); instead, based on double immunofluorescence study, TLR4 immunoreactivity was expressed in non-pyramidal neurons and astrocytes from 2 days postischemia. In addition, TLR4 protein level was lowest at 1 day postischemia and highest 4 days after I/R. On the other hand, NF-κB p65 immunoreactivity was not detected in the CA1 of the sham-operated group, and NF-κB p65 immunoreactivity was not observed until 1 day after I/R. However, NF-κB p65 immunoreactivity began to be expressed in astrocytes at 2 days postischemia, and the immunoreactivity was strong 4 days postischemia. Our results indicate that TLR4 and NF-κB p65 immunoreactivity are changed in CA1 pyramidal neurons and newly expressed in astrocytes, not in microglia, in the CA1 region after transient cerebral ischemia.
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Affiliation(s)
- Ki-Yeon Yoo
- Department of Oral Anatomy, College of Dentistry, Gangneung-Wonju National University, Gangneung 210-702, South Korea
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92
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Koneru R, Kobiler D, Lehrer S, Li J, van Rooijen N, Banerjee D, Glod J. Macrophages play a key role in early blood brain barrier reformation after hypothermic brain injury. Neurosci Lett 2011; 501:148-51. [PMID: 21782894 DOI: 10.1016/j.neulet.2011.06.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/20/2011] [Accepted: 06/30/2011] [Indexed: 12/15/2022]
Abstract
The inflammatory response following traumatic injury to the central nervous system (CNS) includes the infiltration of large numbers of macrophages. This response has been implicated in both ongoing tissue damage as well as recovery following CNS injury. We investigated the role of invading macrophages on one important aspect of tissue repair in the brain, the reformation of the blood brain barrier (BBB). We used liposomal clodronate to deplete monocytes and tissue macrophages. This method led to a marked reduction in the accumulation of F4/80-expressing cells at sites of hypothermic brain injury in a murine model. The integrity of the blood brain barrier over time following injury was assessed by permeability of fluorescent labeled albumin. The reduction in macrophages at the injury site was accompanied by a delay in early reformation of the blood brain barrier. In control animals the permeability of the BBB to FITC-labeled albumin returned to normal levels by seven days post-injury. In macrophage-depleted mice leakage of albumin was still observed at seven days post-injury. These results suggest that macrophages play an important role in early post-traumatic reformation of the BBB.
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Affiliation(s)
- Rajeth Koneru
- Department of Pediatrics, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, USA
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93
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Su SY, Hsieh CL. Anti-inflammatory effects of Chinese medicinal herbs on cerebral ischemia. Chin Med 2011; 6:26. [PMID: 21740583 PMCID: PMC3152532 DOI: 10.1186/1749-8546-6-26] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Accepted: 07/09/2011] [Indexed: 01/30/2023] Open
Abstract
Abstracts Recent studies have demonstrated the importance of anti-inflammation, including cellular immunity, inflammatory mediators, reactive oxygen species, nitric oxide and several transcriptional factors, in the treatment of cerebral ischemia. This article reviews the roles of Chinese medicinal herbs as well as their ingredients in the inflammatory cascade induced by cerebral ischemia. Chinese medicinal herbs exert neuroprotective effects on cerebral ischemia. The effects include inhibiting the activation of microglia, decreasing levels of adhesion molecules such as intracellular adhesion molecule-1, attenuating expression of pro-inflammatory cytokines such as interleukin-1β and tumor necrosis factor-α, reducing inducible nitric oxide synthase and reactive oxygen species, and regulating transcription factors such as nuclear factor-κB.
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Affiliation(s)
- Shan-Yu Su
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan.
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94
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Abstract
Whole genome expression microarrays can be used to study gene expression in blood, which comes in part from leukocytes, immature platelets, and red blood cells. Since these cells are important in the pathogenesis of stroke, RNA provides an index of these cellular responses to stroke. Our studies in rats have shown specific gene expression changes 24 hours after ischemic stroke, hemorrhage, status epilepticus, hypoxia, hypoglycemia, global ischemia, and following brief focal ischemia that simulated transient ischemic attacks in humans. Human studies show gene expression changes following ischemic stroke. These gene profiles predict a second cohort with >90% sensitivity and specificity. Gene profiles for ischemic stroke caused by large-vessel atherosclerosis and cardioembolism have been described that predict a second cohort with >85% sensitivity and specificity. Atherosclerotic genes were associated with clotting, platelets, and monocytes, and cardioembolic genes were associated with inflammation, infection, and neutrophils. These gene profiles predicted the cause of stroke in 58% of cryptogenic patients. These studies will provide diagnostic, prognostic, and therapeutic markers, and will advance our understanding of stroke in humans. New techniques to measure all coding and noncoding RNAs along with alternatively spliced transcripts will markedly advance molecular studies of human stroke.
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Qi J, Buzas K, Fan H, Cohen JI, Wang K, Mont E, Klinman D, Oppenheim JJ, Howard OMZ. Painful pathways induced by TLR stimulation of dorsal root ganglion neurons. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 186:6417-26. [PMID: 21515789 PMCID: PMC3098909 DOI: 10.4049/jimmunol.1001241] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that TLRs 3, 7, and 9 are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP-10), IL-1α, IL-1β, and PGE(2), which have previously been shown to augment pain. Further, TLR ligands upregulated the expression of a nociceptive receptor, transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1-expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive oligodeoxynucleotide, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain.
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Affiliation(s)
- Jia Qi
- Laboratory of Molecular Immunoregulation, Cancer and Inflammatory Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, USA
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Carty M, Bowie AG. Evaluating the role of Toll-like receptors in diseases of the central nervous system. Biochem Pharmacol 2011; 81:825-37. [PMID: 21241665 DOI: 10.1016/j.bcp.2011.01.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/04/2011] [Accepted: 01/06/2011] [Indexed: 02/06/2023]
Abstract
A key part of the innate immune system is a network of pattern recognition receptors (PRRs) and their associated intracellular signalling pathways. Toll-like receptors (TLRs) are one such group of PRRs that detect pathogen associated molecular patterns (PAMPs). Activation of the TLRs with their respective agonists results in the activation of intracellular signalling pathways leading to the expression of proinflammatory mediators and anti-microbial effector molecules. Activation of the innate immune system through TLRs also triggers the adaptive immune response, resulting in a comprehensive immune program to eradicate invading pathogens. It is now known that immune surveillance and inflammatory responses occur in the central nervous system (CNS). Furthermore it is becoming increasingly clear that TLRs have a role in such CNS responses and are also implicated in the pathogenesis of a number of conditions in the CNS, such as Alzheimer's, stroke and multiple sclerosis. This is likely due to the generation of endogenous TLR agonists in these conditions which amplifies a detrimental neurotoxic inflammatory response. However TLRs in some situations can be neuroprotective, if triggered in a favourable context. This review aims to examine the recent literature on TLRs in the CNS thus demonstrating their importance in a range of infectious and non-infectious diseases of the brain.
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Affiliation(s)
- Michael Carty
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland.
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