Rheumatoid Arthritis: Ospelt C

Ospelt C, Gay S. · Center of Experimental Rheumatology, University Hospital Zurich and Zurich Center of Integrative Human Physiology, Gloriastrasse 23, CH-8091 Zürich, Switzerland. · Best Pract Res Clin Rheumatol. · Pubmed #18455682 No free full text.

Abstract: Infiltration by inflammatory cells, thickening of the lining layer, and destructive invasion into cartilage and bone are pathognomic features of the synovium in rheumatoid arthritis (RA). However, the most common cell types at the sites of invasion are resident cells of the joint, in particular synovial fibroblasts. These cells differ from healthy synovial fibroblasts in their morphology, their expression of proto-oncogenes and antiapoptotic molecules, and in their lack of certain tumor suppressor genes. Through their production of proinflammatory cytokines and chemokines mediated by signaling via Toll-like receptors, they are not only effector cells but also active parts of the innate immune system attracting inflammatory immune cells to the synovium. Most importantly, by producing matrix-degrading molecules they contribute strongly to the destructive mechanisms operative in RA.

Stanczyk J, Ospelt C, Gay S. · Center of Experimental Rheumatology, University Hospital Zurich, Zurich Center of Integrative Human Physiology, University of Zurich, Switzerland. · Curr Opin Rheumatol. · Pubmed #18388515 No free full text.

Abstract: PURPOSE OF REVIEW: In this review, we outline the landscape of recent developments regarding small molecule compounds for the treatment of inflammatory disorders by discussing drug candidates currently in the pipeline. We also stress the fact that novel techniques are available to evaluate the safety of new therapeutics at an early stage of development. RECENT FINDINGS: Regulation of signal transduction has evolved into an important field of drug research, and small molecule inhibitors of a number of pathways are tested as new anti-inflammatory agents. For rheumatic diseases, specific Jak3 and Syk inhibitors are, so far, the most successful compounds due to their good efficacy, representing a significant advantage over p38 mitogen-activated protein kinase inhibitors. Additional benefit in the treatment of inflammatory diseases may be provided by targeting CD80, IL-12/IL-23, AP-1 transcription factor and receptors modulating cellular activation like chemokine receptors, Toll-like receptors and adenosine A3 receptor. SUMMARY: There is a big hope that novel small molecule drugs, which are rationally designed, based on scientific advancements and biotechnological improvements, will achieve or even exceed efficacy of protein drugs. Thereby, new therapeutic alternatives would be given, and chances for improved outcomes in the care of rheumatic patients provided.

Sánchez-Pernaute O, Ospelt C, Neidhart M, Gay S. · Fundación Jiménez Díaz, Madrid, Spain. · J Autoimmun. · Pubmed #18155418 No free full text.

Abstract: The innate immune response needs to be tightly regulated to balance elimination of microorganisms with the magnitude of inflammation. The rupture of this balance is crucial for the outcome of diseases such as rheumatoid arthritis (RA) in which an overflowed proinflammatory response is associated with self-damage. Epigenetics alludes to systems controlling gene expression and silencing independent of the germline, but stable enough to be inherited by daughter cells upon mitosis. We will show in this review how pathological processes in RA can be shaped by epigenetics, which may in turn explain differences in phenotypes between subgroups of patients and also between subsets of fibroblasts within the joint. On the whole, the concourse of epigenetic mechanisms can precipitate the aggressive behaviour of cells and the rupture of peripheral tolerance. Targeting these emerging regulatory pathways is a promising approach for RA therapeutics.

Rengel Y, Ospelt C, Gay S. · Center of Experimental Rheumatology, University Hospital Zürich, Gloriastrasse, CH-8091 Zurich, Switzerland. · Arthritis Res Ther. · Pubmed #18001502 links to  free full text

Abstract: Proteinases are involved in essential steps in cartilage and bone homeostasis. Consequently, efforts have been made to establish their potential role in the pathology of rheumatic conditions such as rheumatoid arthritis, osteoarthritis and spondyloarthritis. Matrix metalloproteinases (MMPs) are sensitive markers of disease severity and response to treatment, and therefore they have potential in the assessment of rheumatic diseases. Despite disappointing early results with synthetic inhibitors of MMPs, there is still much scope for developing effective and safe MMPs inhibitors, and consequently to deliver new options to inhibit joint destruction.

Ospelt C, Gay S. · University Hospital Zürich, Center of Experimental Rheumatology, Gloriastrasse 23, Zürich, CH-8091, Switzerland. · Curr Opin Investig Drugs. · Pubmed #17520867 No free full text.

Abstract: Rheumatoid arthritis is a chronic autoimmune disease involving progressive destruction of the joints. Although a variety of antirheumatic drugs are in use, they usually only slow, and not halt, disease progression, or reverse the damage to cartilage and bone. Furthermore, treatment has to be discontinued in some cases due to toxicity and/or lack of response. By analyzing the whole transcriptome of a cell or tissue with microarray technology, a newo way of identifying treatments and discovering more about the mechanisms of known drugs has become available. This review discusses the strengths and weaknesses of microarray technology and gives an overview of gene expression studies currently performed in the field of antiheumatic therapies.

Moritz F, Distler O, Ospelt C, Gay RE, Gay S. · Center of Experimental Rheumatology, Department of Rheumatology, University of Zurich, Switzerland. · Nat Clin Pract Rheumatol. · Pubmed #16932675 No free full text.

Abstract: Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by systemic inflammation and joint destruction. Novel therapies have emerged during the past decade, marking a new era in the treatment of RA. Meanwhile, in vivo and in vitro gene-transfer studies have provided valuable insights into mechanisms of disease pathogenesis. Advanced gene-delivery techniques and animal models promise further progress in RA research and the development of novel therapeutic strategies for this disease. In this article we provide an overview of the wide spectrum of potential targets that have been identified so far, discuss currently available gene-transfer methods, and outline the barriers that need to be overcome for these approaches to be successfully applied in daily practice.

Stanczyk J, Ospelt C, Gay RE, Gay S. · Center of Experimental Rheumatology and World Health Organization Collaborating Center for Molecular Biology and Novel Therapeutic Strategies, Department of Rheumatology, University Hospital Zurich, Switzerland. · Curr Opin Rheumatol. · Pubmed #16582690 No free full text.

Abstract: PURPOSE OF REVIEW: Modern molecular biology offers a unique opportunity to gain a comprehensive picture of gene expression in a disease state. This review presents recent findings in the field of synovial fibroblast biology contributing to knowledge of the pathogenesis of rheumatoid arthritis. RECENT FINDINGS: Recently it has become apparent that innate immune response pathways play a critical role in driving synovial activation and contribute significantly to the turnover of leukocytes in the synovial compartment. In addition, microparticles have been identified as a new class of potent mediators, broadening the known spectrum of cell-derived modulators in the joint. Numerous research groups gained new insights into detailed molecular mechanisms leading to the invasiveness of rheumatoid arthritis synovial fibroblasts, the disturbance in the regulation of apoptosis, and synovial cell-cell and cell-matrix interactions. SUMMARY: The key role of synovial fibroblasts in the pathogenesis of rheumatoid arthritis has been highlighted by the fact that these cells not only are the main executors of cartilage and bone destruction but also modulate numerous interactions in rheumatoid joints. Moreover, it has become evident that integration of a large body of information is indispensable to get a comprehensive outlook on synovial activation in the pathology of rheumatoid arthritis.

Ospelt C, Neidhart M, Gay RE, Gay S. · University Hospital, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #16052564 links to  free full text

This publication has no abstract.

Ospelt C, Kyburz D, Pierer M, Seibl R, Kurowska M, Distler O, Neidhart M, Muller-Ladner U, Pap T, Gay RE, Gay S. · WHO Collaborating Center for Molecular Biology and Novel Therapeutic Strategies for Rheumatic Diseases, Clinic for Rheumatology, University Hospital, Gloriastrasse 25, CH-8091 Zurich, Switzerland. · Ann Rheum Dis. · Pubmed #15479881 links to  free full text

This publication has no abstract.

Ospelt C, Neidhart M, Gay RE, Gay S. · Center of Experimental Rheumatology, University Hospital, Gloriastrasse 25, CH-8091 Zurich, Switzerland. · Front Biosci. · Pubmed #15353290 No free full text.

Abstract: Rheumatoid arthritis (RA) is a chronic inflammatory disease with progressive articular damage. Activated cells of the synovium produce pro-inflammatory and matrix-degrading effector molecules, which maintain the inflammation and lead to the destruction of the involved joints. In addition to macrophages and T- and B-cells, fibroblast-like synoviocytes must be considered key cells in driving the pathological processes. They can be distinguished by their transformed-appearing phenotype and their invasion into adjacent cartilage and bone. Synovial activation is driven by pro-inflammatory cytokines as well as cytokine independent pathways including endogenous retroviral elements and Toll-like receptors (TLR). These pathways are connected by a complex network of autocrine and paracrine acting factors. Another feature of RA synovium is hyperplasia of the lining layer, which results from increased proliferation and decreased apoptosis of synovial fibroblasts. Thanks to new techniques in basic research, novel insights into the cellular and molecular mechanisms of the pathogenesis of RA were gained and led to the development of new, specific therapeutic strategies.

Ospelt C, Brentano F, Jüngel A, Rengel Y, Kolling C, Michel BA, Gay RE, Gay S. · Center of Experimental Rheumatology, University Hospital Zurich, and Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #19180502 No free full text.

Abstract: OBJECTIVE: Since pattern-recognition receptors (PRRs), in particular Toll-like receptors (TLRs), were found to be overexpressed in the synovium of rheumatoid arthritis (RA) patients and to play a role in the production of disease-relevant molecules, we sought to determine the expression, regulation, and function of the PRR nucleotide-binding oligomerization domain 2 (NOD-2) in RA. METHODS: Expression of NOD-2 in synovial tissues was analyzed by immunohistochemistry. Expression and induction of NOD-2 in RA synovial fibroblasts (RASFs) were measured by conventional and real-time polymerase chain reaction (PCR) analyses. Levels of interleukin-6 (IL-6) and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA) and expression of matrix metalloproteinases (MMPs) by ELISA and/or real-time PCR. NOD-2 expression was silenced with small interfering RNA. Western blotting with antibodies against phosphorylated and total p38, JNK, and ERK, as well as inhibitors of p38, JNK, and ERK was performed. Activation of NF-kappaB was measured by electrophoretic mobility shift assay. RESULTS: NOD-2 was expressed by fibroblasts and macrophages in the synovium of RA patients, predominantly at sites of invasion into articular cartilage. In cultured RASFs, no basal expression of messenger RNA for NOD-2 was detectable, but was induced by poly(I-C), lipopolysaccharide, and tumor necrosis factor alpha. After up-regulation of NOD-2 by TLR ligands, its ligand muramyl dipeptide (MDP) increased the expression of IL-6 and IL-8 via p38 and NF-kappaB. Stimulation with MDP further induced the expression of MMP-1, MMP-3, and MMP-13. CONCLUSION: Not only TLRs, but also the PRR NOD-2 is expressed in the synovium of RA patients, and activation of NOD-2 acts synergistically with TLRs in the production of proinflammatory and destructive mediators. Therefore, NOD-2 might contribute to the initiation and perpetuation of chronic, destructive inflammation in RA.

Ospelt C, Brentano F, Rengel Y, Stanczyk J, Kolling C, Tak PP, Gay RE, Gay S, Kyburz D. · Center of Experimental Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #19035519 No free full text.

Abstract: OBJECTIVE: To analyze the expression, regulation, and biologic relevance of Toll-like receptors (TLRs) 1-10 in synovial and skin fibroblasts and to determine the expression levels of TLRs 2, 3, and 4 in synovial tissues from patients with early rheumatoid arthritis (RA), longstanding RA, and osteoarthritis (OA). METHODS: Expression of TLRs 1-10 in RA synovial fibroblasts (RASFs), OASFs, and skin fibroblasts was analyzed by real-time polymerase chain reaction (PCR). Fibroblasts were stimulated with tumor necrosis factor alpha, interleukin-1beta (IL-1beta), bacterial lipopeptide, poly(I-C), lipopolysaccharide, and flagellin. Production of IL-6 was determined by enzyme-linked immunosorbent assay and induction of TLRs 2-5, matrix metalloproteinases (MMPs) 3 and 13 messenger RNA by real-time PCR. Expression of TLRs 2-4 in synovial tissues was analyzed by immunohistochemistry. RESULTS: Synovial fibroblasts expressed TLRs 1-6, but not TLRs 7-10. Among the expressed TLRs, TLR-3 and TLR-4 were the most abundant in synovial fibroblasts, and stimulation of synovial fibroblasts with the TLR-3 ligand poly(I-C) led to the most pronounced increase in IL-6, MMP-3, and MMP-13. In contrast, skin fibroblasts did not up-regulate MMP-3 or MMP-13 after stimulation with any of the tested stimuli. In synovial tissues from patients with early RA, TLR-3 and TLR-4 were highly expressed and were comparable to the levels of patients with longstanding RA. These expression levels were elevated as compared with those in OA. CONCLUSION: Our findings of high expression of TLRs, particularly TLRs 3 and 4, at an early stage of RA and the reactivity of synovial fibroblasts in vitro to TLR ligands suggest that TLR signaling pathways resulting in persistent inflammation and joint destruction are activated early in the disease process.

Brentano F, Ospelt C, Stanczyk J, Gay RE, Gay S, Kyburz D. · Center of Experimental Rheumatology, University Hospital and Zurich Center of Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland. · Ann Rheum Dis. · Pubmed #18276743 No free full text.

Abstract: OBJECTIVE: Interleukin (IL)23, composed of a p19 and a p40 subunit, is suggested to play key roles in rheumatoid arthritis (RA), dependent on the promotion and proliferation of IL17-producing T helper (Th)17 cells. However, previous studies on IL23 expression in human tissues were based on the p19 subunit only. We aimed to study the expression and regulation of IL23 subunits p19 and p40 in RA compared to patients with osteoarthritis (OA). METHODS: The expression of p19 and p40 in synovial tissues was analysed by in situ hybridisation and immunohistochemistry. IL23 in RA and OA synovial fluids and sera was determined by ELISA. Toll-like receptor (TLR)-dependent induction of p19, p40 and bioactive IL23 was determined in RA synovial fibroblasts (RASF), monocytes and monocyte-derived dendritic cells (MDDCs) by real-time PCR and reverse transcriptase (RT)-PCR, Western blot and functional assays. RESULTS: The p19 subunit was abundantly expressed in RA but not in OA synovial tissues. p19 was most prominently expressed by RASF in the synovial lining layer and at the site of invasion, but no heterodimeric IL23 was detected at these sites. Correspondingly, soluble IL23 was not detectable or found at very low levels in synovial fluids and sera of patients with RA. By in vitro experiments, we confirmed that TLR-activated RASF expressed p19 but not p40, in contrast to monocytes, which produced IL23 following TLR stimulation. CONCLUSION: The TLR-dependent induction of p19 but not p40 in RASF and the abundant expression of p19 along with the low or undetectable levels of IL23 in patients with RA provides strong evidence that p19 does not necessarily indicate the presence of IL23, as has been proposed to date.

Müller-Ladner U, Ospelt C, Gay S, Distler O, Pap T. · Justus-Liebig-University Giessen, Department of Rheumatology and Clinical Immunology, Kerckhoff-Clinic Bad Nauheim, Benekestrasse, D-61231 Bad Nauheim, Germany. · Arthritis Res Ther. · Pubmed #18177509 links to  free full text

Abstract: For some time synovial fibroblasts have been regarded simply as innocent synovial cells, mainly responsible for synovial homeostasis. During the past decade, however, a body of evidence has accumulated illustrating that rheumatoid arthritis synovial fibroblasts (RASFs) are active drivers of joint destruction in rheumatoid arthritis. Details regarding the intracellular signalling cascades that result in long-term activation and synthesis of proinflammatory molecules and matrix-degrading enzymes by RASFs have been analyzed. Molecular, cellular and animal studies have identified various interactions with other synovial and inflammatory cells. This expanded knowledge of the distinct role played by RASFs in the pathophysiology of rheumatoid arthritis has moved these fascinating cells to the fore, and work to identify targeted therapies to inhibit their joint destructive potential is underway.

Brentano F, Schorr O, Ospelt C, Stanczyk J, Gay RE, Gay S, Kyburz D. · University Hospital, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #17763446 links to  free full text

Abstract: OBJECTIVE: To study possible mechanisms that mediate induction of the recently described adipocytokine pre-B cell colony-enhancing factor (PBEF) in joints of patients with rheumatoid arthritis (RA), and to analyze whether levels of PBEF correlate with disease severity and whether PBEF itself has the potential to act as a proinflammatory and destructive mediator in RA. METHODS: RA synovial fibroblasts (RASFs) and monocytes were stimulated with Toll-like receptor (TLR) ligands, cytokines, and recombinant human PBEF or were transfected with PBEF expression constructs or with PBEF-specific small interfering RNA. Production of interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNFalpha) was measured by enzyme-linked immunosorbent assay, and expression of matrix metalloproteinases (MMPs) was assessed by real-time polymerase chain reaction. PBEF expression in synovial tissue, synovial fluid, serum, and SFs was assessed by immunohistochemistry, in situ hybridization, Western blotting, and enzyme immunoassays. RESULTS: In RASFs, PBEF was up-regulated by TLR ligands and cytokines that are characteristically present in the joints of patients with RA. In synovial tissue, RASFs were the major PBEF-expressing cells. A predominance of PBEF was found in the synovial lining layer and at sites of invasion into cartilage. Levels of PBEF in serum and synovial fluid correlated with the degree of inflammation and clinical disease activity. Moreover, PBEF itself activated the transcription factors NF-kB and activator protein 1 and induced IL-6, IL-8, MMP-1, and MMP-3 in RASFs as well as IL-6 and TNFalpha in monocytes. PBEF knockdown in RASFs significantly inhibited basal and TLR ligand-induced production of IL-6, IL-8, MMP-1, and MMP-3. CONCLUSION: Our findings establish PBEF as a proinflammatory and destructive mediator of joint inflammation in RA and identify PBEF as a potential therapeutic target.

Ospelt C, Kurowska-Stolarska M, Neidhart M, Michel BA, Gay RE, Laufer S, Gay S. · Center of Experimental Rheumatology, University Hospital Zurich, Switzerland. · Ann Rheum Dis. · Pubmed #17666446 No free full text.

Abstract: OBJECTIVE: To find previously unknown properties of ML3000, a competitive inhibitor of the cyclooxygenase and the lipoxygenase (LO) pathway. METHODS: Gene expression of ML3000 treated and untreated rheumatoid arthritis synovial fibroblasts were measured with Affymetrix gene arrays. Downregulation of chemokine (C-X-C motif) ligands CXCL9, CXCL10 and CXCL11 was verified with Real-time polymerase chain reaction, CXCL10 protein levels were determined with ELISA. Rheumatoid arthritis synovial fibroblasts were treated with the cyclooxygenase inhibitor naproxen, the 5-LO inhibitor BWA4C and the 5-lipoxygenase-activating protein (FLAP) inhibitor MK886, and consecutive changes in CXCL10 protein levels measured. 5-LO expression was determined by polymerase chain reaction and Western blot. RESULTS: In synovial fibroblasts and monocyte-derived macrophages ML3000 inhibited the tumour necrosis factor induced expression of CXCL9, CXCL10 and CXCL11, which are all ligands of the chemokine receptor CXCR3. No effect was observed in monocytes. Whereas inhibition of the cyclooxygenase pathway or the FLAP protein showed no effect, blockade of 5-LO significantly downregulated CXCL10 protein levels. 5-LO mRNA was detected in monocytes and in monocyte-derived macrophages. All tested cell types expressed 5-LO protein. CONCLUSIONS: ML3000 effectively downregulates CXCR3 ligands. This study confirms that a thorough analysis of the impact of a drug on its target cells cannot only reveal unexpected properties of a substance, but also helps to understand the underlying molecular mechanisms. Accordingly, our data provide the basis for further clinical studies testing the application of ML3000 in diseases such as rheumatoid arthritis or multiple sclerosis.

Jüngel A, Baresova V, Ospelt C, Simmen BR, Michel BA, Gay RE, Gay S, Seemayer CA, Neidhart M. · Centre of Experimental Rheumatology, Department of Rheumatology, University Hospital Zurich, Gloriastrasse 25, CH 8091 Zurich, Switzerland. · Ann Rheum Dis. · Pubmed #16284094 links to  free full text

Abstract: BACKGROUND: Histone acetylation/deacetylation has a critical role in the regulation of transcription by altering the chromatin structure. OBJECTIVE: To analyse the effect of trichostatin A (TSA), a streptomyces metabolite which specifically inhibits mammalian histone deacetylases, on TRAIL-induced apoptosis of rheumatoid arthritis synovial fibroblasts (RASF). METHODS: Apoptotic cells were detected after co-treatment of RASF with TRAIL (200 ng/ml) and TSA (0.5, 1, and 2 micromol/l) by flow cytometry using propidium iodide/annexin-V-FITC staining. Cell proliferation was assessed using the MTS proliferation test. Induction of the cell cycle inhibitor p21Waf/Cip1 by TSA was analysed by western blot. Expression of the TRAIL receptor-2 (DR5) on the cell surface of RASF was analysed by flow cytometry. Levels of soluble TRAIL were measured in synovial fluid of patients with RA and osteoarthritis (OA) by ELISA. RESULTS: Co-treatment of the cells with TSA and TRAIL induced cell death in a synergistic and dose dependent manner, whereas TRAIL and TSA alone had no effect or only a modest effect. RASF express DR5 (TRAIL receptor 2), but treatment of the cells with TSA for 24 hours did not change the expression level of DR5, as it is shown for cancer cells. TSA induced cell cycle arrest in RASF through up regulation of p21Waf1/Cip1. Levels of soluble TRAIL were significantly higher in RA than in OA synovial fluids. CONCLUSION: Because TSA sensitises RASF for TRAIL-induced apoptosis, it is concluded that TSA discloses sensitive sites in the cascade of TRAIL signalling and may represent a new principle for the treatment of RA.

Ospelt C, Gay S. · Center of Experimental Rheumatology, Zürich, Switzerland. · Arthritis Res Ther. · Pubmed #16207343 links to  free full text

Abstract: Somatic mutations of mitochondrial DNA have been detected in various pathologies such as cancer, neurodegenerative diseases, cardiac disorders and aging in general. Now it has been found that patients with rheumatoid arthritis also have a higher incidence of mitochondrial mutations in synoviocytes and synovial tissue compared with patients with osteoarthritis. Furthermore, it has been shown that these mutations possibly result in changed peptides that are presented by major histocompatibility complex II and thus might be recognized as non-self by the immune system. Further studies will show whether these mutations are actually able to trigger autoimmune inflammation in rheumatoid arthritis or whether they must be considered epiphenomena of cellular damage in chronic inflammation.

Neidhart M, Jüngel A, Ospelt C, Michel BA, Gay RE, Gay S. · University Hospital Zurich, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #16200606 links to  free full text

This publication has no abstract.