Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0014070 (encephalomyelitis)
13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipoteichoic acid (LTA) is a surface-associated adhesion amphiphile from Gram-positive bacteria and regulator of autolytic wall enzymes (muramidases). It is released from the bacterial cells mainly after bacteriolysis induced by lysozyme, cationic peptides from leucocytes, or beta-lactam antibiotics. It binds to target cells either non-specifically, to membrane phospholipids, or specifically, to CD14 and to Toll-like receptors. LTA bound to targets can interact with circulating antibodies and activate the complement cascade to induce a passive immune kill phenomenon. It also triggers the release from neutrophils and macrophages of reactive oxygen and nitrogen species, acid hydrolases, highly cationic proteinases, bactericidal cationic peptides, growth factors, and cytotoxic cytokines, which may act in synergy to amplify cell damage. Thus, LTA shares with endotoxin (lipopolysaccharide) many of its pathogenetic properties. In animal studies, LTA has induced arthritis, nephritis, uveitis, encephalomyelitis, meningeal inflammation, and periodontal lesions, and also triggered cascades resulting in septic shock and multiorgan failure. Binding of LTA to targets can be inhibited by antibodies, phospholipids, and specific antibodies to CD14 and Toll, and in vitro its release can be inhibited by non-bacteriolytic antibiotics and by polysulphates such as heparin, which probably interfere with the activation of autolysis. From all this evidence, LTA can be considered a virulence factor that has an important role in infections and in postinfectious sequelae caused by Gram-positive bacteria. The future development of effective antibacteriolitic drugs and multidrug strategies to attenuate LTA-induced secretion of proinflammatory agonists is of great importance to combat septic shock and multiorgan failure caused by Gram-positive bacteria.
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PMID:Role of lipoteichoic acid in infection and inflammation. 1194 87

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune demyelinating disease commonly used to model the pathogenetic mechanisms involved in multiple sclerosis (MS). In this study, we examined the effects of immunization with the myelin oligodendrocyte glycoprotein MOG(35-55) on the expression of molecules of the innate immune system, namely toll-like receptor 2 (TLR2) and CD14. Expression of the mRNA encoding TLR2 increased in the choroid plexus, the leptomeninges and within few isolated cells in the CNS parenchyma 4 to 8 days after immunization with MOG. At day 10, the signal spread across the meninges, few perivascular regions and over isolated groups of parenchymal cells. Three weeks after the MOG treatment, at which time animals showed severe clinical symptoms, a robust expression of both TLR2 and CD14 transcripts occurred in barrier-associated structures, as well as parenchymal elements of the spinal cord, and within numerous regions of the brain including, the medulla, cerebellum and the cortex. Dual labeling provided the anatomical evidence that microglia/macrophages were positive for TLR2 in the brain of EAE mice. The regions that exhibited chronic expression of TLR2 and CD14 were also associated with an increase in NF-kappaB activity and transcriptional activation of genes encoding numerous proinflammatory molecules. The present data provide evidence that receptors of the pathogen-associated molecular patterns are strongly induced in the CNS of EAE mice, further reinforcing the concept that the innate immune system plays a determinant role in this autoimmune demyelinating disease.
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PMID:The clinical course of experimental autoimmune encephalomyelitis is associated with a profound and sustained transcriptional activation of the genes encoding toll-like receptor 2 and CD14 in the mouse CNS. 1214 99

Between one-third and one-half of all cases of sepsis are known to be caused by gram-positive microorganisms through the cell wall component, e.g. lipoteichoic acid (LTA). Gram-positive bacteria are also known to induce encephalomyelitis and meningeal inflammation, and enhance the production of nitric oxide (NO) via expression of inducible nitric oxide synthase (iNOS) in murine tissue macrophages. It remains to be explored if LTA could activate microglia considered to be resident brain macrophages. We report here that LTA derived from gram-positive bacteria (Staphylococcus aureus) significantly induces NO release and iNOS expression in primary microglia. LTA-induced NO accumulation was detected at 2 h in microglial culture and was significantly attenuated by pretreatment with anti-CD14, complement receptor type 3 (CR3) or scavenger receptor (SR) antibodies. LTA activated mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase, p38 MAPK or c-Jun N-terminal kinase in cultured microglia. LTA-elicited microglial NO production was also drastically suppressed by SB203580 (p38 MAPK inhibitor) or pyrrolidine dithiocarbamate (an inhibitor of nuclear factor kappaB), indicating that p38 MAPK and nuclear factor kappaB were involved in microglial NO release after LTA challenge. These results suggest that gram-positive bacterial product such as LTA can activate microglia to release NO via the signal transduction pathway involving multiple LTA receptors (e.g. CD14, CR3 or SR), p38 MAPK and nuclear factor kappaB. The in vivo study further confirmed that administered intracerebrally LTA induced considerable noticeable iNOS, phospho-IkappaB and phospho-p38 MAPK expression in microglia/macrophages.
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PMID:Signal transduction pathways of nitric oxide release in primary microglial culture challenged with gram-positive bacterial constituent, lipoteichoic acid. 1587 5

Innate immune receptors are crucial for defense against microorganisms. Recently, a cross-talk between innate and adaptive immunity has been considered. Here, we provide first evidence for a role of the key innate immune receptor, LPS receptor (CD14) in pathophysiology of experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis. Indicating a functional importance in vivo, we show that CD14 deficiency increased clinical symptoms in active experimental autoimmune encephalomyelitis. Consistent with these observations, CD14 deficient mice exhibited a markedly enhanced infiltration of monocytes and neutrophils in brain and spinal cord. Moreover, we observed an increased immunoreactivity of CD14 in biopsy and post mortem brain tissues of multiple sclerosis patients compared to age-matched controls. Thus, the key innate immune receptor, CD14, may be of pathophysiological relevance in experimental autoimmune encephalomyelitis and multiple sclerosis.
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PMID:The LPS receptor, CD14, in experimental autoimmune encephalomyelitis and multiple sclerosis. 1654 33

The IL-12 family of cytokines, which include IL-12, IL-23, and IL-27, play critical roles in the differentiation of Th1 cells and are believed to contribute to the development of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Relatively little is known concerning the expression of IL-12 family cytokines by cells of the CNS, the affected tissue in MS. Previously, we and others demonstrated that peroxisome proliferator-activated receptor (PPAR)-gamma agonists suppress the development of EAE, alter T cell proliferation and phenotype, and suppress the activation of APCs. The present studies demonstrated that PPAR-gamma agonists, including the naturally occurring 15-deoxy-Delta(12,14)-PGJ(2) and the synthetic thiazoladinedione rosiglitazone, inhibited the induction of IL-12p40, IL-12p70 (p35/p40), IL-23 (p19/p40), and IL-27p28 proteins by LPS-stimulated primary microglia. In primary astrocytes, LPS induced the production of IL-12p40, IL-23, and IL-27p28 proteins. However, IL-12p70 production was not detected in these cells. The 15-deoxy-Delta(12,14)-PGJ(2) potently suppressed IL-12p40, IL-23, and IL-27p28 production by primary astrocytes, whereas rosiglitazone suppressed IL-23 and IL-27p28, but not IL-12p40 in these cells. These novel observations suggest that PPAR-gamma agonists modulate the development of EAE, at least in part, by inhibiting the production of IL-12 family cytokines by CNS glia. In addition, we demonstrate that PPAR-gamma agonists inhibit TLR2, MyD88, and CD14 expression in glia, suggesting a possible mechanism by which these agonists modulate IL-12 family cytokine expression. Collectively, these studies suggest that PPAR-gamma agonists may be beneficial in the treatment of MS.
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PMID:Peroxisome proliferator-activated receptor-gamma agonists suppress the production of IL-12 family cytokines by activated glia. 1723 41

The interleukin-12 (IL-12) family of cytokines which includes IL-12, IL-23, and IL-27 play critical roles in T cell differentiation and are important modulators of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Previously, we demonstrated that peroxisome proliferator-activated receptor (PPAR) -alpha agonists suppress the development of EAE. The present studies demonstrated that the PPAR-alpha agonist fenofibrate inhibited the secretion of IL-12p40, IL-12p70 (p35/p40), IL-23 (p19/p40), and IL-27p28 by lipopolysaccharide-stimulated microglia. The cytokines interferon-gamma and tumor necrosis factor-alpha also stimulated IL-12 p40 and IL-27 p28 expression by microglia, which was suppressed by fenofibrate. Furthermore, fenofibrate inhibited microglial expression of CD14 which plays a critical role in TLR signaling, suggesting a mechanism by which this PPAR-alpha agonist regulates the production of these pro-inflammatory molecules. In addition, fenofibrate suppressed the secretion of IL-12p40, IL-23, and IL-27p28 by lipopolysaccharide-stimulated astrocytes. Importantly, fenofibrate suppression of EAE was associated with decreased expression of IL-12 family cytokine mRNAs as well as mRNAs encoding TLR4, CD14, and MyD88 known to play critical roles in MyD88-dependent TLR signaling. These novel observations suggest that PPAR-alpha agonists including fenofibrate may modulate the development of EAE, at least in part, by suppressing the production of IL-12 family cytokines and MyD88-dependent signaling.
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PMID:Peroxisome proliferator-activated receptor-alpha agonist fenofibrate regulates IL-12 family cytokine expression in the CNS: relevance to multiple sclerosis. 1772 29

The possibility to generate and expand tolerogenic dendritic cells (DC) with TGF-beta1 in vitro opens new therapeutic perspectives for the treatment of autoimmune diseases. In the present study, GM-CSF+IL-4 induced the differentiation of DC from adherent peripheral blood mononuclear cells, which had a higher expression of HLA-DR, CD86 and CD1a and the capacity to stimulate T cells. TGF-beta1 alone slightly promoted the generation of antigen presenting cells (APC) with higher expression of CD14, but did not differentiate them into E-cadherin+Langerhans cell (LC)-like DC. TGF-beta1-driven APC exhibited the morphology, phenotypes and functions of tolerogenic immature DC, and had lower capacity to stimulate T cells. In vivo experiment demonstrates that TGF-beta1-treated APC exhibited the therapeutic potential in Lewis rats with experimental autoimmune encephalomyelitis (EAE), followed by increase of IL-10 production in lymph nodes and decrease of inflammatory cells in spinal cords. Most importantly, GM-CSF/IL-4 used in DC preparation abolished the effect of TGF-beta1 to induce tolerogenic APC in vitro and in vivo. The results reveal that the usage of GM-CSF for the generation of tolerogenic DC should not be copied from DC preparation for anti-tumor therapy.
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PMID:The presence of GM-CSF and IL-4 interferes with effect of TGF-beta1 on antigen presenting cells in patients with multiple sclerosis and in rats with experimental autoimmune encephalomyelitis. 1806 Nov 54

Monkeypox virus (MPV) is an orthopoxvirus with considerable homology to variola major, the etiologic agent of smallpox. Although smallpox was eradicated in 1976, the outbreak of MPV in the U.S. highlights the health hazards associated with zoonotic infections. Like other orthopoxviruses, MPV encodes a secreted chemokine binding protein, vCCI that is abundantly expressed and secreted from MPV infected cells. EMSA data shows vCCI efficiently binds rhesus MIP-1alpha (rhMIP-1alpha) at near one to one stoichiometry. In vitro chemotaxis experiments demonstrate that vCCI completely inhibits rhMIP-1alpha mediated chemotaxis, while in vivo recruitment assays in rhesus macaques using chemokine-saturated implants show a decrease in the number of CD14(+) cells responding to rhMIP-1alpha when vCCI is present, suggesting vCCI is effectively inhibiting chemokine function both in vitro and in vivo. More importantly, we demonstrate that vCCI can diminish the severity of the acute phase and completely inhibit the relapsing phase of experimental allergic encephalomyelitis (EAE) disease. These data represent the first in vitro and in vivo characterization of vCCI emphasizing its function as a potent inhibitor of rhMIP-1alpha. Furthermore, the ability of vCCI to inhibit relapsing EAE disease represents a novel therapeutic approach for treating chemokine-mediated diseases.
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PMID:Monkeypox virus viral chemokine inhibitor (MPV vCCI), a potent inhibitor of rhesus macrophage inflammatory protein-1. 1863 66

Th17 and Th1 play an important role in multiple sclerosis for which copolymer I (COP-I) is a treatment option. We described here that the treatment effect of COP-I correlated with its unique regulatory properties on differentiation and survival of Th17 in experimental autoimmune encephalomyelitis mice, which was mediated through down-regulation of STAT3 phosphorylation. The effect of COP-I on Th17 differentiation required CD14(+) monocytes through IL-6 signaling as a key mediator to regulate STAT3 phosphorylation and subsequent RORgammat expression in Th17 cells. The observed effect was markedly dampened when monocytes were genetically deficient for IL-6. Similar regulatory properties of COP-I were demonstrated in human Th17 differentiation. The study revealed the differential regulatory roles and the novel mechanism of action of COP-I chiefly responsible for its treatment efficacy in experimental autoimmune encephalomyelitis and multiple sclerosis.
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PMID:Regulatory properties of copolymer I in Th17 differentiation by altering STAT3 phosphorylation. 1954 36

Interleukin (IL)-23 is a heterodimeric cytokine composed of the IL-23-specific subunit p19 and the p40 subunit which also constitutes part of IL-12. IL-23 propagates development of Th17 cells, a novel T cell subset which produces IL-17 but no interferon-gamma or IL-4. For both, IL-23 and IL-23-driven IL-17, a crucial role in autoimmune diseases such as experimental autoimmune encephalomyelitis, collagen-induced arthritis, and colitis is well accepted. Recent studies indicate that there is also a role for IL-23 and IL-17 in tumorigenesis, promoting tumor growth and vascularization, and affecting tumor incidence. We show that human CD14(+) peripheral blood monocyte-derived dendritic cells (DC), as used for clinical applications in anti-tumor immunization strategies, produce high amounts of IL-23. CD40-triggering of immature and mature DC but not of primary monocytes induced a rapid expression of high levels of IL-23, free p40, and minor levels of IL-12. Upon stimulation of DC subsets with a variety of different danger signals such as single stranded and double stranded RNA, bacterial components or viral infections, IL-23 expression pattern was analyzed. Interestingly, co-stimulation with CD40L enabled IL-23 expression by DC subsets towards danger signals to which they have been unresponsive upon single stimulation. Furthermore, we detected two novel splice variants of the IL-23-specific subunit p19 that could be associated with the regulation of IL-23 expression. Data presented here might have an impact on DC-based cancer vaccination strategies and contribute to a better understanding of the complex regulation of the heterodimeric cytokine IL-23.
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PMID:CD40 ligand-triggered human dendritic cells mount interleukin-23 responses that are further enhanced by danger signals. 2007 Oct 30


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