Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003873 (rheumatoid arthritis)
 53,068 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rheumatoid arthritis (RA) is a chronic inflammatory disease, which is mainly characterized by synovial hyperplasia, pathological immune phenomena and progressive destruction of the affected joints. Various cell types are involved in the pathogenesis of RA including T cells, antigen presenting cells, and endothelial cells. Recent experimental evidence suggests that the CD40/CD154 system might play an important role in the development of RA. Our experimental approach focuses on RA synovial fibroblasts (RA-SF) that are able to destroy articular cartilage independent of inflammation. To elucidate the specific role of those cells in RA pathophysiology the following questions are currently addressed: 1. Which mechanisms do activate the RA-SF? 2. How do the activated RA-SF attach to the cartilage? 3. How do RA-SF destroy cartilage and bone? Which mechanisms do activate the RA-SF? The process of activation is poorly understood. It is unclear, how far the synovial hyperplasia of RA resembles tumor diseases. Along this line some contradictory results exist concerning the role of the tumor suppressor protein p53. Some investigations could show the expression of p53 in the synovial lining including p53 mutations in RA synovium and in RASF, while other research groups could not confirm these data. Our group has demonstrated that the tumor suppressor PTEN was less expressed in the synovial lining of RA than in normal synovium, but no PTEN mutations could be found in the RA-SF. In addition, the in vivo and in vitro expression of the anti-apoptotic molecule sentrin suggests a functional resistance of RA-SF to undergo apoptosis. Although it is still unclear, whether certain viruses or viral elements are involved in the pathogenesis of RA (cause, consequence or coincidence?), certain viruses could play a role in the pathogenesis of RA. The endogenous retroviral element L1 was found to be expressed in the synovial lining, at sites of invasion as well as in RA-SF grown in vitro. Moreover, the data indicate that after the initial activation of L1 downstream molecules such as the SAP kinase 4, the met-protoonocogene and the galectin-3 binding protein are upregulated. How do the activated RA-SF attach to the cartilage? It has been suggested that integrins mediate the attachment of RA-SF to fibronectin rich sites of cartilage. Intriguingly, other adhesion molecules such as the vascular cellular adhesion molecule-1 (VCAM) and CS-1, a splice variant of fibronectin, are synthesized by RA-SF. By binding to these adhesion molecules, lymphocytes that express the integrin VLA-4 could be stimulated and thereby maintain the inflammatory process. Osteopontin is an extracellular matrix protein, which is associated with matrix adhesion and metastasis in tumors. In RA synovium, osteopontin was detectable in the synovial lining and at sites of invasion. How do RA-SF destroy cartilage and bone? The destruction of cartilage and bone in RA is mediated by matrix metalloproteinases (MMPs) and cathepsins. MMPs exist as secreted and as membrane bound forms. In vitro models are being developed to simulate the invasive process of RA-SF. In an in vitro model developed in our laboratory, the treatment of RA-SF with anti-CD44 or anti-interleukin-1 (IL-1) minimized matrix degradation of RA-SF. On the other hand, co-culture of RA-SF and U937 cells as well as application of interleukin-1 beta (IL-1 beta) or tumor necrosis factor alpha (TNF alpha) increased the invasiveness of RA-SF. Gene transfer of bovine pancreas trypsin inhibitor (BPMI) or interleukin-10 (IL-10) reduced the invasion of RA-SF, while transduction of interleukin-1 receptor antagonist (IL-1Ra) was chondroprotective. Double gene transfer of IL-10 and IL-1Ra resulted in both inhibition of invasion and chondroprotection.
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PMID:[Rheumatoid arthritis: new developments in the pathogenesis with special reference to synovial fibroblasts]. 1175 30

Interleukin 10 (IL-10) is an anti-inflammatory cytokine produced in the rheumatoid arthritis (RA) joint by macrophages/monocytes and infiltrating peripheral blood derived lymphocytes. Recent data suggest a role for physical cell-to-cell interactions in the production of IL-10. In this report, we have investigated the signalling mechanisms involved in IL-10 production by peripheral blood-derived macrophages upon interaction with fixed CD40L transfectants. IL-10 and tumour necrosis factor alpha (TNF-alpha) are produced by macrophage colony-stimulating factor (M-CSF)-primed monocytes/macrophages in response to CD40 ligation. The utilization of the inhibitors, wortmannin and LY294002, demonstrated a role for phosphatidylinositol 3-kinase (PI3K) whereas rapamycin demonstrated p70 S6-kinase (p70S6K) involvement in the production of IL-10 by these monocytes. The production of TNF-alpha was enhanced by wortmannin and LY294002, suggesting negative regulation by PI3K; however, it was dependent on p70S6K suggesting a PI3K-independent mechanism of p70S6K activation. One alternative pathway that activates p70S6K independently of PI3K and also differentiates between IL-10 and TNF-alpha is the p42/44 mitogen-activated protein kinase (MAPK), which regulates TNF-alpha production in a PI3K-independent manner. These observations suggest that CD40 ligation induces macrophage IL-10 and TNF-alpha production, the mechanism of which is p70S6K-dependent yet bifurcates at the level of PI3K and p42/44 MAPK.
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PMID:CD40 ligation induces macrophage IL-10 and TNF-alpha production: differential use of the PI3K and p42/44 MAPK-pathways. 1179 23

Expression of inflammatory cytokines is augmented in the joints of patients with rheumatoid arthritis (RA). We found that cytokine levels are also elevated in the joints of a mouse arthritis model, human T-cell leukemia virus type I (HTLV-I) transgenic (Tg) mouse. Depletion of IL-1 by gene targeting greatly reduced the incidence of the disease, indicating the importance of this cytokine in the development of arthritis. Furthermore, IL-1 receptor antagonist (IL-1Ra)-deficient mice develop autoimmunity and arthritis spontaneously. These observations suggest that excess IL-1 signaling the causes autoimmunity. We show that IL-1 activates the immune system non-specifically by inducing CD40L and OX40 co-signaling molecules on T cells. In this review, the roles of IL-1 in the development of autoimmunity and arthritis in mouse models will be discussed.
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PMID:Roles of IL-1 in the development of rheumatoid arthritis: consideration from mouse models. 1222 May 48

Interleukin (IL)-12, being a major cytokine that induces T helper (Th) 1 differentiation and inflammatory response, has been postulated to be an important mediator of synovial inflammation in rheumatoid arthritis (RA). However, the regulation of IL-12 production in RA has not been elucidated. Our knowledge is mainly based on studies of the production of IL-12p40 and not the functional IL-12p70 heterodimer. We have studied the CD154-induced IL-12p40 and IL-12p70 production by synovial fluid (SF) macrophages from patients with RA. CD40 ligation induced the secretion of IL-12p40 but not IL-12p70. The observed increase in IL-10 and tumor necrosis factor (TNF)-alpha production indicated that SF macrophages responded to CD40 ligation. The expression of p40 mRNA was increased significantly and remained upregulated after CD40 ligation, whereas the increase of p35 transcript expression was observed only transiently and at a lower level. We further observed that dendritic cells (DCs) derived in vitro from SF macrophages produced IL-12p70. Most importantly, IL-4 and IL-13 primed SF macrophages to produce IL-12p70, whereas IFN-gamma was not observed to activate IL-12p70 production in these cells, in contrast with normal peripheral blood monocytes. These results provide novel information about the regulation of IL-12p70 production and the function of the cytokine network in RA.
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PMID:Regulation of CD154-induced interleukin-12 production in synovial fluid macrophages. 1222 12

Rheumatoid arthritis is characterized by synovial joint infiltration of activated CD4(+) T cells and MHC class II(+) APC, and is linked to specific HLA-DR alleles. Candidate autoantigens in synovial fluid and cartilage include type II collagen (CII) and cartilage gp39 (HCgp39). Using preparations of native Ag and T cells derived from Ag-immunized DR4-transgenic mice, we determined that human ex vivo differentiated DR4(+) dendritic cells (DC) and macrophages (Mphi) can mediate MHC class II presentation of CII or HCgp39 epitopes. The form of the Ag (soluble, partially degraded, or particulate) delivered to the APC influenced its presentation by DC and Mphi. DC efficiently presented partially degraded, but not native CII alpha-chains, while Mphi presentation was most efficient after phagocytosis of bead-conjugated CII. Both DC and Mphi presented soluble HCgp39, and activated Mphi from some donors presented epitopes derived from endogenously synthesized HCgp39. When synovial fluid from rheumatoid arthritis patients was used as a source of Ag, DC presentation of HCgp39 and CII epitopes was efficient, indicating that synovial fluid contains soluble forms of CII and HCgp39 amenable to internalization, processing, and presentation. These data support the hypothesis that CII and HCgp39 are autoantigens and that their class II-mediated presentation by DC and Mphi to T cells in vivo has a critical role in the pathogenesis of human rheumatoid arthritis.
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PMID:Differential MHC class II-mediated presentation of rheumatoid arthritis autoantigens by human dendritic cells and macrophages. 1244 76

Rheumatoid arthritis (RA) is a serious medical problem, with approximately 1% of the people in the world affected. The disease is autoimmune in nature and characterized by chronic inflammation of the synovial tissue in multiple joints, which leads to joint destruction, although the etiopathogenesis has not been elucidated completely. It is remarkable that expression of inflammatory cytokines is augmented in the joints. We previously reported on an inflammatory arthropathy resembling RA that develops in high incidence among transgenic (Tg) mice that carry the human T cell leukemia virus type I (HTLV-I) tax gene. Autoimmune pathogenesis was suggested in this RA model, and levels of cytokines including IL-1 were elevated in the joints of these Tg mice. Depletion of IL-1 by gene targeting greatly reduced the incidence of the disease, indicating the importance of this cytokine in the development of arthritis. Furthermore, IL-1 receptor antagonist (IL-1Ra)-deficient mice develop autoimmunity and arthritis spontaneously. These observations suggest that excess IL-1 signaling causes autoimmunity. We show that IL-1 activates the immune system non-specifically by inducing CD40L and OX40 co-signaling molecules on T cells. In this review, the roles of IL-1 in the development of autoimmunity and arthritis will be discussed in correlation with the development of new drugs.
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PMID:[Mouse models for rheumatoid arthritis and their use in drug development]. 1249 6

The autoimmune response is executed via cognate interactions between effector immune cells and antigen presenting cells. Cognate interactions provide the immune effectors with specific signals generated through the antigen receptor as well as with second, non-specific signals, generated from the interaction of pairs of cell-surface molecules (costimulatory molecules) present on their plasma membrane. Disruption of this second, non-specific costimulatory signal results in the interruption of the productive (auto)immune response, leading to anergy, a state of immune unresponsiveness. The CD28:B7 families of molecules and the CD40:CD40L pair of molecules are considered as critical costimulatory elements. Disruption of the CD28:B7 interaction using a genetically engineered soluble form of the inhibitory molecule CTLA4 in vitro, as well as in experimental models of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), led to the inhibition of the autoimmune response. Similarly, promising data stem from the use of an anti-CD40L monoclonal antibody (mAb) in murine SLE. While such treatments prevent the development of autoimmunity in animal models, this preventive approach is inapplicable to human diseases. However, the rational bench-to-bedside approach led investigators to clinical trials of CTLA4-Ig and of two different humanized anti-human CD40L mAbs in patients with RA and SLE, respectively. Initial experience with the use of CTLA4-Ig in patients with RA is encouraging, since in one short-term trial the construct was well-tolerated and produced clinically meaningful improvement of the disease in a significant proportion of those treated. Surprisingly, the anti-CD40L mAb treatment approach in human lupus was not fruitful, since short-term administration of the anti-CD40L mAb ruplizumab in lupus nephritis was correlated with life-threatening prothrombotic activity despite initial encouraging data in the serology and renal function of the patients. Also, IDEC-131 anti-CD40L mAb treatment did not prove to be clinically effective in human SLE, despite being well tolerated. Precise tailoring of the administration schemes for these novel therapeutic modalities is awaited.Finally, conceptually different approaches to block costimulation by inhibiting the induced expression of costimulatory molecules or the transmission of their specific intracytoplasmic signal have already produced encouraging preliminary results.
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PMID:Costimulation blockade in the treatment of rheumatic diseases. 1504 25

Many tissue injuries and immune mediated pathologies such as graft allo-rejections were found to involve CD40-CD40 ligand (CD40L, CD154) signaling pathway. The disruption of this pathway in many animal models led to the improvement of graft survival in these models. CD40-CD154 interactions were also shown to play a significant role in the maintenance of autoimmunity, and the production of auto-antibodies in systemic lupus erythematosus (SLE). High-level expression of CD154 has been detected on T cells from patients with active SLE, rheumatoid arthritis (RA) and other autoimmune diseases, indicating that such cells could account for the high-level expression of immune accessory molecules on B cells of patients with active disease. An increased serum level of soluble CD154 was also reported in SLE, RA, and Sjogren's disease in correlation with the relevant auto-antibodies and with the clinical disease activity. Anti-CD154 antibody therapy prevents auto-antibody production and renal immune complex deposition in lupus nephritis, indicating that disruption of this pathway could be a beneficial treatment in SLE. However, the etiology of the higher than expected number of thromboembolic events in anti-CD154 treated SLE patients should be investigated and preventive measures should be considered.
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PMID:The role of CD40-CD154 interactions in autoimmunity and the benefit of disrupting this pathway. 1562 72

CD40 and CD154 belong to the tumor necrosis factor (TNF) receptor superfamily and the TNF superfamily, respectively. Evidence is accumulating that indicates the importance of this receptor-ligand pair in the immunopathogenesis of autoimmune diseases. The CD40-CD154 interaction influences antigen presentation, tolerance, autoantibody production and tissue damage, all of which are relevant to the development and perpetuation of autoimmune diseases. Among the collagen diseases, the CD40-CD154 interaction has been intensively investigated in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In this article, both basic and clinical research suggesting the involvement of the CD40-CD154 interaction in SLE, RA, inflammatory myopathies, systemic sclerosis and antiphospholipid syndrome are reviewed. The results of clinical trials from CD40-CD154 blockade are also analyzed. CD40-CD154 blockade in animal models of autoimmune diseases has been reported to be a promising novel therapeutic approach and, thus, has attracted great attention from pharmaceutical companies. However, the development of CD40-CD154 blockers with both significant clinical efficacy and safety has not been successful and research advances in this field are eagerly awaited.
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PMID:[Involvement of CD40-CD154 interaction in immunopathogenesis of collagen diseases and its application to a novel therapeutic strategy]. 1567 91

Considering the relation between synovial inflammation and global disease activity in rheumatoid arthritis (RA) and the distinct but heterogeneous histology of spondyloarthropathy (SpA) synovitis, the present study analyzed whether histopathological features of synovium reflect specific phenotypes and/or global disease activity in SpA. Synovial biopsies obtained from 99 SpA and 86 RA patients with active knee synovitis were analyzed for 15 histological and immunohistochemical markers. Correlations with swollen joint count, serum C-reactive protein concentrations, and erythrocyte sedimentation rate were analyzed using classical and multiparameter statistics. SpA synovitis was characterized by higher vascularity and infiltration with CD163+ macrophages and polymorphonuclear leukocytes (PMNs) and by lower values for lining-layer hyperplasia, lymphoid aggregates, CD1a+ cells, intracellular citrullinated proteins, and MHC-HC gp39 complexes than RA synovitis. Unsupervised clustering of the SpA samples based on synovial features identified two separate clusters that both contained different SpA subtypes but were significantly differentiated by concentration of C-reactive protein and erythrocyte sedimentation rate. Global disease activity in SpA correlated significantly with lining-layer hyperplasia as well as with inflammatory infiltration with macrophages, especially the CD163+ subset, and with PMNs. Accordingly, supervised clustering using these synovial parameters identified a cluster of 20 SpA patients with significantly higher disease activity, and this finding was confirmed in an independent SpA cohort. However, multiparameter models based on synovial histopathology were relatively poor predictors of disease activity in individual patients. In conclusion, these data indicate that inflammatory infiltration of the synovium with CD163+ macrophages and PMNs as well as lining-layer hyperplasia reflect global disease activity in SpA, independently of the SpA subtype. These data support a prominent role for innate immune cells in SpA synovitis and warrant further evaluation of synovial histopathology as a surrogate marker in early-phase therapeutic trials in SpA.
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PMID:Infiltration of the synovial membrane with macrophage subsets and polymorphonuclear cells reflects global disease activity in spondyloarthropathy. 1574 84


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