Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IL-17 has been associated with multiple inflammatory disorders such as rheumatoid arthritis, asthma and multiple sclerosis. As these diseases require long-term treatment we turned to an auto-vaccine strategy for IL-17 neutralization in vivo. Mouse IL-17A was covalently linked to ovalbumin and used to immunize C57BL/6 mice. This vaccine induced the production of antibodies that blocked IL-17A bioactivity in vitro but did not react with the other IL-17 isoforms, including IL-17F. As the half-life of the Ab titers after the last immunogen administration was approximately 4 months, the vaccine provides for long lasting and selective inhibition of IL-17A activity in vivo. A monoclonal Ab (mAb) derived from these mice showed the same specificity for IL-17A. To test the ability of the vaccine to confer protection against an IL-17-dependent disorder, SJL mice were vaccinated with IL-17-OVA and encephalomyelitis (EAE) was induced by proteolipid protein (PLP) peptide 139-151. Vaccinated mice were completely protected against the disease. The above-mentioned anti-IL-17A mAb also prevented EAE development. The absence of clinical symptoms contrasted with unaltered PLP-induced cytokine production in vitro and unmodified anti-PLP IgG titers and isotypes. These results suggest that an anti-IL-17A auto-vaccine offers new perspectives for therapy of autoimmune diseases.
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PMID:Development of an anti-IL-17A auto-vaccine that prevents experimental auto-immune encephalomyelitis. 1707 13

After activation, CD4+ helper T (T(H)) cells differentiate into distinct effector subsets that are characterized by their unique cytokine expression and immunoregulatory function. During this differentiation, T(H)1 and T(H)2 cells produce interferon-gamma and interleukin (IL)-4, respectively, as autocrine factors necessary for selective lineage commitment. A distinct T(H) subset, termed T(HIL-17), T(H)17 or inflammatory T(H) (T(H)i), has been recently identified as a distinct T(H) lineage mediating tissue inflammation. T(H)17 differentiation is initiated by transforming growth factor-beta and IL-6 (refs 5-7) and reinforced by IL-23 (ref. 8), in which signal transduction and activators of transcription (STAT)3 and retinoic acid receptor-related orphan receptor (ROR)-gamma mediate the lineage specification. T(H)17 cells produce IL-17, IL-17F and IL-22, all of which regulate inflammatory responses by tissue cells but have no importance in T(H)17 differentiation. Here we show that IL-21 is another cytokine highly expressed by mouse T(H)17 cells. IL-21 is induced by IL-6 in activated T cells, a process that is dependent on STAT3 but not ROR-gamma. IL-21 potently induces T(H)17 differentiation and suppresses Foxp3 expression, which requires STAT3 and ROR-gamma, which is encoded by Rorc. IL-21 deficiency impairs the generation of T(H)17 cells and results in protection against experimental autoimmune encephalomyelitis. IL-21 is therefore an autocrine cytokine that is sufficient and necessary for T(H)17 differentiation, and serves as a target for treating inflammatory diseases.
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PMID:Essential autocrine regulation by IL-21 in the generation of inflammatory T cells. 1765 76

Although interleukin (IL) 17 has been extensively characterized, the function of IL-17F, which has an expression pattern regulated similarly to IL-17, is poorly understood. We show that like IL-17, IL-17F regulates proinflammatory gene expression in vitro, and this requires IL-17 receptor A, tumor necrosis factor receptor-associated factor 6, and Act1. In vivo, overexpression of IL-17F in lung epithelium led to infiltration of lymphocytes and macrophages and mucus hyperplasia, similar to observations made in IL-17 transgenic mice. To further understand the function of IL-17F, we generated and analyzed mice deficient in IL-17F or IL-17. IL-17, but not IL-17F, was required for the initiation of experimental autoimmune encephalomyelitis. Mice deficient in IL-17F, but not IL-17, had defective airway neutrophilia in response to allergen challenge. Moreover, in an asthma model, although IL-17 deficiency reduced T helper type 2 responses, IL-17F-deficient mice displayed enhanced type 2 cytokine production and eosinophil function. In addition, IL-17F deficiency resulted in reduced colitis caused by dextran sulfate sodium, whereas IL-17 knockout mice developed more severe disease. Our results thus demonstrate that IL-17F is an important regulator of inflammatory responses that seems to function differently than IL-17 in immune responses and diseases.
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PMID:Regulation of inflammatory responses by IL-17F. 1841 38

Interleukin-17A (IL-17A) is a cytokine produced by T helper 17 (Th17) cells and plays important roles in the development of inflammatory diseases. Although IL-17F is highly homologous to IL-17A and binds the same receptor, the functional roles of this molecule remain largely unknown. Here, we demonstrated with Il17a(-/-), Il17f(-/-), and Il17a(-/-)Il17f(-/-) mice that IL-17F played only marginal roles, if at all, in the development of delayed-type and contact hypersensitivities, autoimmune encephalomyelitis, collagen-induced arthritis, and arthritis in Il1rn(-/-) mice. In contrast, both IL-17F and IL-17A were involved in host defense against mucoepithelial infection by Staphylococcus aureus and Citrobacter rodentium. IL-17A was produced mainly in T cells, whereas IL-17F was produced in T cells, innate immune cells, and epithelial cells. Although only IL-17A efficiently induced cytokines in macrophages, both cytokines activated epithelial innate immune responses. These observations indicate that IL-17A and IL-17F have overlapping yet distinct roles in host immune and defense mechanisms.
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PMID:Differential roles of interleukin-17A and -17F in host defense against mucoepithelial bacterial infection and allergic responses. 1914 13

The need for reporter lines able to faithfully track Th17 cells in vivo has become an issue of exceptional importance. To address this, we generated a mouse strain in which Cre recombinase is expressed from the IL-17F promoter. Crossing the IL-17F-Cre allele to a conditional enhanced yellow fluorescent protein (EYFP) reporter mouse yielded the IL-17F-Cre(EYFP) strain, in which IL-17F expression is twinned with EYFP in live IL-17F-expressing cells. Although we demonstrate that IL-17F expression is restricted to CD4(+) T cells during experimental autoimmune encephalomyelitis, IL-17F-Cre(EYFP) CD8 T cells robustly expressed IL-17F in response to TGF-beta, IL-6, and IL-23. Fate mapping of IL-17F-expressing reporter T cells revealed a significant down-regulation of Th17 cytokines after homeostatic expansion in RAG1-deficient animals. Despite this loss of effector phenotype, committed Th17 cells were resistant to Foxp3 expression in vitro or in vivo. Thus, the IL-17F-Cre strain furthers our understanding of Th17 biology.
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PMID:Cutting edge: an IL-17F-CreEYFP reporter mouse allows fate mapping of Th17 cells. 1915 67

The immunological mechanisms underlying autoimmunity are being elucidated through genetic and functional analyses in both humans and rodent models. However, acceptance of models as valid equivalents of human disease is variable, and the validation of defined human candidate molecules in experimental models is hitherto limited. We thus aimed to determine the kinetic expression of several Multiple Sclerosis (MS) candidate genes in the myelin oligodendrocyte glycoprotein (MOG)-induced rat experimental autoimmune encephalomyelitis (EAE) model using susceptible DA and resistant PVG inbred strains. Increased expression of MS candidate genes IL2RA and IL7RA associated with disease susceptibility. Higher expression of these candidate genes and IL18R1 in susceptible rats may lead to enhancement of the disease-driving T(H)1 and T(H)17 pathways. Susceptible DA rats had augmented marker molecules of these pathways and upon restimulation with autoantigen produced increased effector molecules including IFN-gamma, IL-17F and IL-22. The altered T helper cell differentiation pathways led to differences in a MOG-specific proliferative and autoantibody response, which ultimately results in infiltration in the central nervous system and EAE induction. Our results validate the MOG-induced EAE model as having similar mechanisms to human MS and determined the kinetics of several disease mechanisms in relevant tissues.
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PMID:Characterization of Multiple Sclerosis candidate gene expression kinetics in rat experimental autoimmune encephalomyelitis. 1926 41

IL-27 is secreted by APCs in response to inflammatory stimuli and exerts a proinflammatory Th1-enhancing activity but also has significant anti-inflammatory functions. We examined the molecular mechanism by which IL-27 regulates TGFbeta plus IL-6- or IL-23-dependent Th17 development in the mouse and human systems. IL-27 inhibited the production of IL-17A and IL-17F in naive T cells by suppressing, in a STAT1-dependent manner, the expression of the Th17-specific transcription factor RORgamma t. The in vivo significance of the role of IL-27 was addressed in delayed-type hypersensitivity response and experimental autoimmune encephalomyelitis (EAE). By generating mice deficient for the p28 subunit of IL-27, we showed that IL-27 regulated the severity of delayed-type hypersensitivity response and EAE through its effects on Th17 cells. Furthermore, up-regulation of IL-10 in the CNS, which usually occurs late after EAE onset and plays a role in the resolution of the disease, was notably absent in IL-27p28(-/-) mice. These results show that IL-27 acts as a negative regulator of the developing IL-17A response in vivo, suggesting a potential therapeutic role for IL-27 in autoimmune diseases.
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PMID:IL-27 blocks RORc expression to inhibit lineage commitment of Th17 cells. 1938 Aug 22

The alpha7 nicotinic acetylcholine receptor (nAChR) was recently described as an anti-inflammatory target in both macrophages and T cells. Its expression by immune cells may explain the epidemiological data claiming a negative link between cigarette smoking and several inflammatory diseases. In this study, we determined the immunological effects of alpha7 nAChR activation by nicotine. Our results indicate that the alpha7 nAChR is expressed on the surface of CD4(+) T cells and that this expression is up-regulated upon immune activation. Nicotine reduced T cell proliferation in response to an encephalitogenic Ag, as well as the production of Th1 (TNF-alpha and IFN-gamma) and Th17 cytokines (IL-17, IL-17F, IL-21, and IL-22). IL-4 production was increased in the same setting. Attenuation of the Th1 and Th17 lineages was accompanied by reduced T-bet (50%) and increased GATA-3 (350%) expression. Overall, nicotine induced a shift to the Th2 lineage. However, alpha7(-/-)-derived T cells were unaffected by nicotine. Furthermore, nicotine reduced NF-kappaB-mediated transcription as measured by IL-2 and IkappaB transcription. In vivo, administration of nicotine (2 mg/kg s.c.) suppressed the severity of CD4(+) T cell-mediated disease experimental autoimmune encephalomyelitis. alpha7(-/-) mice were refractory to nicotine treatment, although disease severity in those animals was reduced, due to impairment in Ag presentation. Accordingly, CD4(+) and CD11b(+) cells infiltration into the CNS, demyelination, and axonal loss were reduced. Our data implicate a role for the alpha7 nAChR in immune modulation and suggest that alpha7 nAChR agonists may be effective in the treatment of inflammatory disorders.
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PMID:Activation of the cholinergic anti-inflammatory system by nicotine attenuates neuroinflammation via suppression of Th1 and Th17 responses. 1984 75

It has been suggested that IL-17RC forms a complex with IL-17RA to mediate the functions of IL-17A and IL-17F homodimers as well as IL-17A/F heterodimers. It is still unclear whether IL-17RC is absolutely required for the signaling of IL-17 cytokines in vivo. By using Il-17rc-deficient mice, we show that IL-17RC is essential for the signaling of IL-17A, IL-17F, and IL-17A/F both in vitro and in vivo. IL-17RC does not preassociate with IL-17RA on the cell surface; rather IL-17A can induce the formation of an IL-17RC and IL-17RA complex. This process is not dependent on the intracellular similar expression to fibroblast growth factor genes and IL-17Rs (SEFIR) domain of IL-17RC, but the SEFIR is essential in IL-17A signal transduction. Finally, Il-17rc(-/-) mice develop much milder disease in an experimental autoimmune encephalomyelitis model, supporting an essential role for IL-17RC in mediating immune-mediated CNS inflammation.
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PMID:IL-17RC is required for IL-17A- and IL-17F-dependent signaling and the pathogenesis of experimental autoimmune encephalomyelitis. 2023 94

Interferon-beta (IFN-beta) is the major treatment for multiple sclerosis. However, this treatment is not always effective. Here we have found congruence in outcome between responses to IFN-beta in experimental autoimmune encephalomyelitis (EAE) and relapsing-remitting multiple sclerosis (RRMS). IFN-beta was effective in reducing EAE symptoms induced by T helper type 1 (T(H)1) cells but exacerbated disease induced by T(H)17 cells. Effective treatment in T(H)1-induced EAE correlated with increased interleukin-10 (IL-10) production by splenocytes. In T(H)17-induced disease, the amount of IL-10 was unaltered by treatment, although, unexpectedly, IFN-beta treatment still reduced IL-17 production without benefit. Both inhibition of IL-17 and induction of IL-10 depended on IFN-gamma. In the absence of IFN-gamma signaling, IFN-beta therapy was ineffective in EAE. In RRMS patients, IFN-beta nonresponders had higher IL-17F concentrations in serum compared to responders. Nonresponders had worse disease with more steroid usage and more relapses than did responders. Hence, IFN-beta is proinflammatory in T(H)17-induced EAE. Moreover, a high IL-17F concentration in the serum of people with RRMS is associated with nonresponsiveness to therapy with IFN-beta.
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PMID:T helper type 1 and 17 cells determine efficacy of interferon-beta in multiple sclerosis and experimental encephalomyelitis. 2037 43


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