Spondylarthritides and related entities: entheses and hypotheses.
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HLA-B27 Antigen↗
Biomedical subjects
Steffen Gay
Publications and source records attributed to Steffen Gay.
Imatinib mesylate reduces production of extracellular matrix and prevents development of experimental dermal fibrosis.
OBJECTIVE: Imatinib mesylate is a clinically well-tolerated small molecule inhibitor that exerts selective, dual inhibition of the transforming growth factor beta (TGFbeta) and platelet-derived growth factor (PDGF) pathways. This study was undertaken to test the potential use of imatinib mesylate as an antifibrotic drug for the treatment of dermal fibrosis in systemic sclerosis (SSc). METHODS: The expression of extracellular matrix (ECM) proteins in SSc and normal dermal fibroblasts was analyzed by real-time polymerase chain reaction, Western blot, and Sircol collagen assay. Proliferation capacity was assessed with the MTT assay. Cell viability was analyzed by mitochondrial membrane potential and by annexin V/propidium iodide staining. Bleomycin-induced experimental dermal fibrosis was used to assess the antifibrotic effects of imatinib mesylate in vivo. RESULTS: Imatinib mesylate efficiently reduced basal synthesis of COL1A1, COL1A2, and fibronectin 1 messenger RNA in SSc and normal dermal fibroblasts, in a dose-dependent manner. The induction of ECM proteins after stimulation with TGFbeta and PDGF was also strongly and dose-dependently inhibited by imatinib mesylate. These results were confirmed at the protein level. Imatinib mesylate did not alter proliferation or induce apoptosis and necrosis in dermal fibroblasts. Consistent with the in vitro findings, imatinib mesylate reduced dermal thickness, the number of myofibroblasts, and synthesis of ECM proteins in experimental dermal fibrosis, without evidence of toxic side effects. CONCLUSION: These data show that imatinib mesylate at biologically relevant concentrations has potent antifibrotic effects in vitro and in vivo, without toxic side effects. Considering its favorable pharmacokinetics and clinical experience with its use in other diseases, imatinib mesylate is a promising candidate for the treatment of fibrotic diseases such as SSc.
Aged↗
The role of membrane lipids in the induction of macrophage apoptosis by microparticles.
Microparticles are membrane-derived vesicles that are released from cells during activation or cell death. These particles can serve as mediators of intercellular cross-talk and induce a variety of cellular responses. Previous studies have shown that macrophages undergo apoptosis after phagocytosing microparticles. Here, we have addressed the hypothesis that microparticles trigger this process via lipid pathways. In these experiments, microparticles induced apoptosis in primary macrophage cells or cell lines (RAW 264.7 or U937) with up to a 5-fold increase. Preincubation of macrophages with phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)BP) reduced the microparticle-induced apoptosis in a dose-dependent manner. PtdIns(3,5)BP is a specific inhibitor of the acid sphingomyelinase and thus can block the generation of pro-apoptotic ceramides. Similarly, the pre-incubation of macrophages with PtdIns(3,5)BP prevented microparticle-induced upregulation of caspase 8, which is a major target molecule of ceramide action in the apoptosis pathway. PtdIns(3,5)BP, however, had no effect on the spontaneous rate of apoptosis. To evaluate further signaling pathways induced by microparticles, the extracellular signal regulated kinase (ERK-) 1 was investigated. This kinase plays a role in activating phospholipases A2 which cleaves membrane phospholipids into arachidonic acid; microparticles have been suggested to be a preferred substrate for phospholipases A2. As shown in our experiments, microparticles strongly increased the amount of phosphorylated ERK1/2 in RAW 264.7 macrophages in a time-dependent manner, peaking 15 min after co-incubation. Addition of PD98059, a specific inhibitor of ERK1, prevented the increase in apoptosis of RAW 264.7 macrophages. Together, these data suggest that microparticles perturb lipid homeostasis of macrophages and thereby induce apoptosis. These results emphasize the importance of biolipids in the cellular cross-talk of immune cells. Based on the fact that in clinical situations with excessive cell death such as malignancies, autoimmune diseases and following chemotherapies high levels of circulating microparticles might modulate phagocytosing cells, a suppression of the immune response might occur due to loss of macrophages.
Animals↗
Mechanisms of Disease: leukotrienes and lipoxins in scleroderma lung disease--insights and potential therapeutic implications.
Scleroderma interstitial lung disease (SLD) is a leading cause of morbidity and mortality in patients with systemic sclerosis. Although the pathogenesis of SLD is not clear, excessive fibrosis and inflammatory cell infiltration are the main histologic features of this disorder. Leukotrienes and lipoxins are two functionally different classes of lipoxygenase-derived eicosanoids. Leukotrienes are potent proinflammatory mediators and directly and indirectly stimulate fibroblast chemotaxis, proliferation, and collagen synthesis. Lipoxins counter-regulate the proinflammatory actions of leukotrienes and activate resolution of the inflammatory response. In addition, lipoxins inhibit growth-factor-induced fibroblast proliferation and collagen synthesis. Studies using bronchoalveolar lavage have revealed that there is an overproduction of proinflammatory and profibrotic leukotrienes in the lungs of patients with SLD, and that leukotriene levels correlate with inflammatory indices within the lungs. Moreover, the increased levels of leukotrienes in these patients are not balanced by an upregulation of anti-inflammatory and antifibrotic lipoxins. Unopposed actions of leukotrienes might, therefore, induce chronic inflammation and fibrosis in the lungs of SLD patients. Accordingly, pharmacologic correction of a leukotriene-lipoxin imbalance using leukotriene inhibitors or lipoxin analogs might be a new approach to the treatment of SLD.
Cell Proliferation↗
Cytoplasmic destruction of p53 by the endoplasmic reticulum-resident ubiquitin ligase 'Synoviolin'.
Synoviolin, also called HRD1, is an E3 ubiquitin ligase and is implicated in endoplasmic reticulum -associated degradation. In mammals, Synoviolin plays crucial roles in various physiological and pathological processes, including embryogenesis and the pathogenesis of arthropathy. However, little is known about the molecular mechanisms of Synoviolin in these actions. To clarify these issues, we analyzed the profile of protein expression in synoviolin-null cells. Here, we report that Synoviolin targets tumor suppressor gene p53 for ubiquitination. Synoviolin sequestrated and metabolized p53 in the cytoplasm and negatively regulated its cellular level and biological functions, including transcription, cell cycle regulation and apoptosis. Furthermore, these p53 regulatory functions of Synoviolin were irrelevant to other E3 ubiquitin ligases for p53, such as MDM2, Pirh2 and Cop1, which form autoregulatory feedback loops. Our results provide novel insights into p53 signaling mediated by Synoviolin.
Animals↗
Attachment to laminin-111 facilitates transforming growth factor beta-induced expression of matrix metalloproteinase-3 in synovial fibroblasts.
BACKGROUND: In the synovial membrane of patients with rheumatoid arthritis (RA), a strong expression of laminins and matrix degrading proteases was reported. AIM: To investigate the regulation of matrix metalloproteinases (MMPs) in synovial fibroblasts (SFs) of patients with osteoarthritis (OA) and RA by attachment to laminin-1 (LM-111) and in the presence or absence of costimulatory signals provided by transforming growth factor beta (TGFbeta). METHODS: SFs were seeded in laminin-coated flasks and activated by addition of TGFbeta. The expression of genes was investigated by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), immunocytochemistry and ELISA, and intracellular signalling pathways by immunoblotting, and by poisoning p38MAPK by SB203580, MEK-ERK by PD98059 and SMAD2 by A-83-01. RESULTS: Attachment of SF to LM-111 did not activate the expression of MMPs, but addition of TGFbeta induced a fivefold higher expression of MMP-3. Incubation of SF on LM-111 in the presence of TGFbeta induced a significant 12-fold higher expression of MMP-3 mRNA, and secretion of MMP-3 was elevated 20-fold above controls. Functional blocking of LM-111-integrin interaction reduced the laminin-activated MMP-3 expression significantly. Stimulation of SF by LM-111 and TGFbeta activated the p38MAPK, ERK and SMAD2 pathways, and inhibition of these pathways by using SB203580, PD98059 or A-83-01 confirmed the involvement of these pathways in the regulation of MMP-3. CONCLUSION: Attachment of SF to LM-111 by itself has only minor effects on the expression of MMP-1 or MMP-3, but it facilitates the TGFbeta-induced expression of MMP-3 significantly. This mode of MMP-3 induction may therefore contribute to inflammatory joint destruction in RA independent of the proinflammatory cytokines interleukin (IL)1beta or tumour necrosis factor (TNF)alpha.
Aged↗
Influence of ibuprofen-arginine on serum levels of nitric oxide metabolites in patients with chronic low back pain--a single-blind, placebo controlled pilot trial (ISRCTN18723747).
OBJECTIVE: To determine whether ibuprofen-arginine has a cyclooxygenase-independent pain modulating property in addition to its known antiinflammatory effect. METHODS: Patients with chronic low back pain were randomly divided into 2 groups treated either with oral ibuprofen-arginine (400 mg) or with placebo. Blood was drawn from study subjects before, during, and after treatment and they were asked each time about the intensity of their pain. Concentrations of nitric oxide (NO) metabolites were determined. RESULTS: Twenty minutes after intake of ibuprofen-arginine, but not after placebo, there was a relevant and significant reduction of NO metabolites in serum. In both groups there was significant analgesic effect compared to baseline. CONCLUSION: An early lowering of the serum NO metabolite levels after ibuprofen-arginine administration could be detected in patients with chronic low back pain.
Analgesics↗
Molecular and cellular basis of rheumatoid joint destruction.
Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with joint destruction. Synovial fibroblasts are key players in this pathological process. They favorise a pro-inflammatory environment in the synovial tissue, interact with the immune system and regulate the differentiation of monocytes into osteoclasts. Synovial hyperplasia is another characteristic of RA, reflecting not only an imbalance between proliferation and apoptosis, but also the migration of cells into the synovial tissue. Gene transfer experiments have been used as important tools for the understanding of molecular and cellular changes that characterize the activated RA synovial fibroblasts. Activated synovial fibroblasts can invade cartilage and bone. Synovial activation is driven by cytokines, such as TNFalpha and IL-1, as well as IL-15, 16, 17, 18, 22, 23, but also by cytokine-independent mechanisms that involve the innate immune system (i.e. TLRs), a unique communication network of microparticles and epigenetic changes (e.g. L1 retroelements).
Animals↗
The potential of adiponectin in driving arthritis.
Articular adipose tissue is a ubiquitous component of human joints, but its local functions are largely unknown. Because recent studies revealed several links between adipose tissue, adipocytokines, and arthritis, we investigated the expression of the adipocytokine adiponectin and its functional role in articular adipose tissue and synovium of patients with different arthritides. In contrast to its protective role in endocrinological and vascular diseases, adiponectin was found to be involved in key pathways of inflammation and matrix degradation in the human joint. The effects of adiponectin in human synovial fibroblasts appear to be highly selective by inducing only two of the main mediators of rheumatoid arthritis pathophysiology, IL-6 and matrix metalloproteinase-1, via the p38 MAPK pathway. Owing to the observation that these effects could be inhibited by different TNF-alpha inhibitors, adipocytokines such as adiponectin may also be key targets for therapeutic strategies in inflammatory joint diseases. In summary, articular adipose tissue and adipocytokines cannot be regarded as innocent bystanders any more in chronic inflammatory diseases such as arthritis.
Adalimumab↗
Antisense strategies in degenerative joint diseases: sense or nonsense?
Oligodeoxynucleotides, ribozymes, and RNA interference make part of the antisense strategy, a new tool proposed to conquer cancer, viral infections, as well as cardiovascular and rheumatic diseases. The silencing effect of antisense strategies is both highly specific and potent - and only requires that the sequence of the target RNA is known. However, so far neither RNAi nor ribozymes have been approved for clinical use and only a single antisense agent is on the market. In the context of degenerative joint diseases, experimental data in the field of antisense strategies are still rare. Several studies from rheumatoid arthritis (RA), an inflammatory condition that leads to the progressive destruction of cartilage and bone within affected joints, however revealed promising results and taught us important lessons that might also be useful in therapeutic approaches for osteoarthritis (OA). To introduce these therapies in clinical practice, however, several hurdles still have to be overcome.
Animals↗
Monocyte chemoattractant protein 1 released from glycosaminoglycans mediates its profibrotic effects in systemic sclerosis via the release of interleukin-4 from T cells.
OBJECTIVE: Monocyte chemoattractant protein 1 (MCP-1; CCL2) has been implicated in the pathogenesis of fibrotic diseases and is up-regulated in patients with systemic sclerosis (SSc). The aim of the present study was to examine the mechanisms by which MCP-1 mediates its profibrotic effects in the setting of SSc. METHODS: The expression of receptors for MCP-1 on dermal fibroblasts was analyzed by real-time polymerase chain reaction and fluorescence-activated cell sorting. The ability of extracellular matrix proteins to bind and release MCP-1 was quantified by enzyme-linked immunosorbent assay. Th0 cells were isolated using a magnetic-activated cell sorting system and were stimulated twice in the presence of MCP-1. The synthesis of collagen was measured using the Sircol collagen assay kit. RESULTS: The glycosaminoglycan chondroitin sulfate, but not fibronectin or collagens, bound and released MCP-1 in a time-dependent manner. MCP-1 that was released from chondroitin sulfate induced the differentiation of interleukin-4 (IL-4)-producing T cells in a dose-dependent manner. In turn, dermal fibroblasts from patients with SSc expressed IL-4 receptor, and stimulation with IL-4 significantly increased the production of collagen in dermal fibroblasts. In contrast, CCR2a and CCR2b, as well as D6 and US28 (other potential receptors of MCP-1), were not detectable in SSc and normal fibroblasts, and their expression was not induced by platelet-derived growth factor, IL-1beta, or IL-4. In addition, MCP-1 had no direct effects on collagen production by fibroblasts. CONCLUSION: MCP-1 has no direct effects on dermal fibroblasts but contributes to fibrosis in patients with SSc by inducing the differentiation of IL-4-producing T cells. Because MCP-1 has both proinflammatory and profibrotic effects, pharmacologic targeting of MCP-1 could be a promising therapeutic approach in SSc.
Adolescent↗
High-resolution molecular analysis for research in rheumatology.
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Arthritis, Rheumatoid↗
Technology insight: gene transfer and the design of novel treatments for rheumatoid arthritis.
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.
Animals↗
Mode of action of hydroxychloroquine in RA-evidence of an inhibitory effect on toll-like receptor signaling.
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Antirheumatic Agents↗
Microparticles as mediators of cellular cross-talk in inflammatory disease.
Microparticles are a heterogeneous population of membrane-coated vesicles which can be released from virtually all cell types during activation or apoptosis. Release occurs from the cell surface in an exogenous budding process involving local rearrangement of the cytoskeleton. Given their origin, these particles can be identified by staining for cell surface markers and annexin V. As shown in in vitro studies, microparticles may represent a novel subcellular element for intercellular communication in inflammation. Thus, microparticles can transfer chemokine receptors and arachidonic acid between cells, activate complement, promote leukocyte rolling and stimulate the release of pro-inflammatory mediators. Under certain conditions, however, microparticles may also exert anti-inflammatory properties by inducing immune cell apoptosis and the production of anti-inflammatory mediators. Microparticles may play an important role in the pathogenesis of rheumatologic diseases as evidenced by their elevation in diseases such as systemic sclerosis (SSc), systemic vasculitis and antiphospholipid antibody syndrome and correlation with clinical events. A role in inflammatory arthritis is suggested by the finding that leukocyte-derived microparticles induce the production of matrix metalloproteinases and cytokines by synovial fibroblasts. Together, these findings point to novel signaling pathways of cellular cross-talk that may operate along the spectrum of soluble cytokines and mediators of direct cell-cell contact.
Animals↗
Synovial cell activation.
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.
Arthritis, Rheumatoid↗
Safety concerns on the development of novel therapeutic drugs.
Along with recent innovative approaches resulting in the development of new therapies such as small molecular inhibitors, therapeutic antibodies, recombinant proteins and gene therapy, there is increasing need for improved understanding of the basic molecular mechanisms that are exploited by such treatments. Helpful tools in the analysis of drug effects include high-throughput screening techniques such as microarrays, which are used in transcriptomics and pharmacogenomics. Although we are far from using these extensive and costly tests in our daily clinical routine, their application in basic research nevertheless takes us closer to individualized therapeutic strategies, in which the optimal therapeutic regimen is identified for each individual patient.
Drug Design↗
Detection of kappa and delta opioid receptors in skin--outside the nervous system.
Opioid receptors (OR) are widely expressed in the central nervous system (CNS). Opioid antinociception might be initiated by activation of OR outside the CNS, indicating targeting of peripheral OR could be useful in the treatment of chronic pain. This study was designed to detect OR in skin tissues of healthy volunteers at both mRNA and protein levels. Skin samples from 10 healthy individuals were investigated. Total isolated RNAs were reverse transcribed, amplified and quantified by real-time PCR. Tissue and skin fibroblast OR protein was detected by immunohistochemistry, Western blot, and immunofluorescence. All skin tissue samples expressed delta- (DOR) and kappa-OR (KOR) mRNAs. Using immunohistochemistry, DOR and KOR were localized in skin fibroblast-like and mononuclear cells. Skin fibroblasts in culture expressed DOR and KOR mRNA. Using immunofluorescence, both DOR and KOR proteins were expressed predominantly on the cell membrane with minor staining in the cytoplasm. We suggest that enhanced expression of DOR and KOR in skin justifies the exploration of selective novel delta and kappa agonists for local pain treatment.
Adult↗