Rheumatoid Arthritis: Foxwell BM

Page TH, Smolinska M, Gillespie J, Urbaniak AM, Foxwell BM. · Kennedy Institute of Rheumatology, Imperial College of Science, Technology and Medicine, 65 Aspenlea Road, London W6 8LH, UK. · Curr Mol Med. · Pubmed #19199943 No free full text.

Abstract: The activity of tyrosine kinases is central to many cellular processes, and accumulating evidence suggests that their role in inflammation is no less profound. Three main tyrosine kinase families, the Src, Tec and Syk kinase families are intimately involved in TLR signalling, the critical first step in cellular recognition of invading pathogens and tissue damage. Their activity results in changes in gene expression in affected cells. Key amongst these genes are the cytokines, which orchestrate both the duration and extent of inflammation. Tyrosine kinases also play important roles in cytokine function, and are implicated in signalling through both pro- and anti-inflammatory cytokines such as TNF, IL-6 and IL-10. Thus, strategies to modulate tyrosine kinase activity have significant therapeutic potential in combating the chronic inflammatory state that is typical of many major health issues that face us today, including Rheumatoid Arthritis, Cardiovascular disease and cancer. Here we review current knowledge of the role of tyrosine kinases in inflammation with particular emphasis on their role in TLR signalling.

Drexler SK, Kong PL, Wales J, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology and Medicine, 65 Aspenlea Road, Hammersmith, London, W6 8LH, UK. · Arthritis Res Ther. · Pubmed #18947379 links to  free full text

Abstract: Rheumatoid arthritis is a multisystemic auto-inflammatory disease affecting up to 1% of the population and leading to the destruction of the joints. Evidence exists for the involvement of the innate as well as the adaptive immune systems in the pathology of the disease. The success of anti-tumour necrosis factor-alpha indicates the importance of pro-inflammatory mediators produced by innate immune cells in rheumatoid arthritis progression. Therefore, considerable efforts have been made in elucidating the signalling pathways leading to the expression of those mediators. This review will concentrate on the role of signalling pathways in innate immune cells in the context of rheumatoid arthritis.

Simmonds RE, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, UK. · Rheumatology (Oxford). · Pubmed #18234712 No free full text.

Abstract: In the synovial cells of patients with RA, activation of the nuclear factor-kappaB (NF-kappaB) pathway results in the transactivation of a multitude of responsive genes that contribute to the inflammatory phenotype, including TNF-alpha from macrophages, matrix metalloproteinases from synovial fibroblasts and chemokines that recruit immune cells to the inflamed pannus. This is largely a consequence of activation of the 'canonical' NF-kappaB pathway that involves heterodimers of p50/p65. Whilst much information on the role of NF-kappaB in inflammation has been gleaned from genetic deficiency of the respective genes in mice, important differences exist in the signalling networks between human and murine immune cells and immortalized cell lines. Despite these differences at the molecular level, the importance of NF-kappaB in inflammation is undisputed and inhibition of the pathway is widely believed to have great potential as a therapeutic target in RA. Commercial effort has gone into developing inhibitors of NF-kappaB activation. However, inhibition of the NF-kappaB activation can result in an exacerbation of inflammation if TNF-alpha production by macrophages is not controlled. It will be important that such inhibitors are carefully monitored before their long-term use in chronic inflammatory conditions such as RA.

Sacre SM, Drexler SK, Andreakos E, Feldmann M, Brennan FM, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, 1 Aspenlea Road, Hammersmith, London W6 8LH, UK. · Ann Rheum Dis. · Pubmed #17934103 No free full text.

Abstract: In the last decade the development of a number of biological therapies has revolutionised the treatment of rheumatic diseases. The first and most widely used of these approaches, tumour necrosis factor (TNF) blockade (infliximab, entanercept, adalimumab), has now been administered to over a million patients. However, the success of these biological therapies has also highlighted their limitations. None of these treatments has shown a 100% patient response; normally responses are in the 50-70% range. As proteins, these drugs cannot be given orally and they are expensive to produce, a cost ultimately borne by the patient/health provider that can seriously limit the availability of these drugs. Lastly, these treatments, whether involving the systemic neutralisation of a cytokine (eg, TNF or IL6 receptor blockade (tocilizumab)), the ablation of a B cell population (anti-CD20, rituximab), or the potential disruption of important cellular interactions as with CTLA4-Ig (abatacept), can cause major perturbations of the immune system, the long-term effects of which are still unclear. At present, treatments such as TNF blockade can result in an increased infectious risk and the reactivation of tuberculosis can be a major issue in certain populations. As with all therapies, there is an increasing large refractory population over time. Therefore, despite the undoubted success of these therapies, there is room for improvement. Although it might be too much to expect any new treatment to affect a "cure" (all the current biological therapies require repeated administrations), there are definite gains to be made in terms of cost, oral bioavailability and a more selective interference with the immune-inflammatory response.

Feldmann M, Brennan FM, Foxwell BM, Taylor PC, Williams RO, Maini RN. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College, 1 Aspenlea Road, London W6 8LH, UK. · J Autoimmun. · Pubmed #16260118 No free full text.

Abstract: The blockade of TNF has had significant impact on the therapy of a number of chronic autoimmune diseases. In this chapter we review the concepts leading up to this therapy in rheumatoid arthritis (RA), how it spreads into other autoimmune diseases, and how greater understanding of its use has led to augmented therapeutic benefit. There are still many limitations, but the prospects for the future are intriguing.

Sacre SM, Andreakos E, Taylor P, Feldmann M, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology and Medicine, 1 Aspenlea Road, Hammersmith, London, W6 8LH, UK. · Expert Rev Mol Med. · Pubmed #16117838 No free full text.

Abstract: In an attempt to combat the pain and damage generated by rheumatoid arthritis (ra), new drugs are being developed to target molecular aspects of the disease process. Recently, a major development has been the use of biologicals (antibodies and soluble receptors) that neutralise the activity of tumour necrosis factor alpha (TNF-alpha) and interleukin 1 (IL-1), both of which are involved in disease progression. An increase in our understanding of cell and molecular biology has resulted in the identification and investigation of potential new targets, and also the refinement and improvement of current therapeutic modalities. This review describes therapies that are approved, in clinical trials or under pre-clinical investigation at the laboratory level, particularly focusing on cytokines, although other therapeutic targets of interest are mentioned.

Andreakos E, Sacre S, Foxwell BM, Feldmann M. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology and Medicine, London, United Kingdom. · Front Biosci. · Pubmed #15970510 No free full text.

Abstract: The study of the role cytokines play in the pathogenesis of rheumatoid arthritis (RA) has provided a whole new range of targets for drug development. Many of them (e.g. TNF, IL-1, IL-6, IL-15 and IL-18) are already being targeted in the clinic with success using neutralizing monoclonal antibodies or soluble cytokine receptors. Targeting TNF, in particular, has shown great efficacy in controlling both the inflammation and structural damage of the joints, setting a new gold standard for the treatment of RA. However, what triggers the production of inflammatory cytokines such as TNF in RA remains to be determined. In this article, we review evidence suggesting that the transcription factor Nuclear Factor kappaB (NF-kappaB) is essential for the expression of both inflammatory cytokines and tissue destructive enzymes in RA. Also, we discuss whether Toll-like receptors (TLRs), major receptors involved in pathogen recognition and potent activators of the NF-kappaB pathway, are involved in triggering the inflammatory and joint destructive process in RA and whether they constitute sensible targets for monoclonal antibodies/soluble receptors and small molecule inhibitors. We conclude that although the TLR- NF-kappaB pathway offers ample opportunities for therapeutic intervention, future drugs to be approved will need to match or exceed the efficacy and safety of anti-TNF agents, with safety the most difficult aspect to predict.

Feldmann M, Andreakos E, Smith C, Bondeson J, Yoshimura S, Kiriakidis S, Monaco C, Gasparini C, Sacre S, Lundberg A, Paleolog E, Horwood NJ, Brennan FM, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Charing Cross Hospital Campus, Arthritis Research Campaign Building, 1 Aspenlea Road, London W6 8LH, UK. · Ann Rheum Dis. · Pubmed #12379614 links to  free full text

Abstract: There is increasing evidence that NF-kappaB is a major, if not the major transcription factor regulating inflammation and immunity. While this implies that blocking NF-kappaB might be therapeutically beneficial, it raises clear questions regarding the balance between efficacy and safety. In this brief review we discuss the effects of NF-kappaB blockade in rheumatoid arthritis, inflammation and immunity, and consider possible therapeutic targets within the NF-kappaB family.

Andreakos ET, Foxwell BM, Brennan FM, Maini RN, Feldmann M. · Faculty of Medicine, Kennedy Institute of Rheumatology Division, Imperial College of Science, Technology and Medicine, 1 Aspenlea Road, Hammersmith, London W6 8LH, UK. · Cytokine Growth Factor Rev. · Pubmed #12220545 No free full text.

Abstract: The increasing understanding of the role of cytokines in autoimmunity, and the observation that tumour necrosis factor alpha (TNFalpha) is central to the inflammatory and destructive process common to several human autoimmune diseases, has led to a new generation of therapeutics, the TNFalpha blocking agents. In this article, we review the current knowledge of the role of cytokines in autoimmunity as unravelled by studies both in the laboratory and the clinic. In addition, we discuss future prospects of the anti-TNFalpha therapy that may involve combination therapy with other anti-cytokine or anti-T cell biologicals, or the use of small chemicals targeting molecules involved in TNFalpha production such as NF-kappaB and p38 MAPK. The future developments of anti-TNFalpha and anti-cytokine therapy in general will be interesting.

Horwood NJ, Smith C, Andreakos E, Quattrocchi E, Brennan FM, Feldmann M, Foxwell BM. · Kennedy Institute of Rheumatology Division, Imperial College Faculty of Medicine, London, UK. · Arthritis Res. · Pubmed #12110141 No free full text.

Abstract: The elucidation of the signalling pathways involved in inflammatory diseases, such as rheumatoid arthritis, could provide long sought after targets for therapeutic intervention. Gene regulation is complex and varies depending on the cell type, as well as the signal eliciting gene activation. However, cells from certain lineages, such as macrophages, are specialised to degrade exogenous material and consequently do not easily transfect. Methods for high-efficiency gene transfer into primary cells of various lineages and disease states are desirable, as they remove the uncertainties associated with using transformed cell lines. Significant research has been undertaken into the development of nonviral and viral vectors for basic research, and as vehicles for gene therapy. We briefly review the current methods of gene delivery and the difficulties associated with each system. Adenoviruses have been used extensively to examine the role of various cytokines and signal transduction molecules in the pathogenesis of rheumatoid arthritis. This review will focus on the involvement of different signalling molecules in the production of tumour necrosis factor alpha by macrophages and in rheumatoid synovium. While the NF-kappaB pathway has proven to be a major mediator of tumour necrosis factor alpha production, it is not exclusive and work evaluating the involvement of other pathways is ongoing.

Feldmann M, Brennan FM, Foxwell BM, Maini RN. · Kennedy Institute of Rheumatology, Hammersmith, London, UK. · Curr Dir Autoimmun. · Pubmed #11791466 No free full text.

This publication has no abstract.

Feldmann M, Maini RN, Bondeson J, Taylor P, Foxwell BM, Brennan FM. · Kennedy Institute of Rheumatology, Hammersmith, London, UK. · Adv Exp Med Biol. · Pubmed #11505970 No free full text.

Abstract: As we enter the 2000's it is clear that cytokine blockade is an effective therapeutic strategy for rheumatoid arthritis. In this brief review, we will review the rationale for anti TNFalpha therapy, the current status of therapy and focus on the regulation of TNFalpha production in rheumatoid synovium. New approaches to studying TNF regulation in RA and of elucidating the controversial role of T cells in this complex disease will be described.

Foxwell BM, Bondeson J, Brennan F, Feldmann M. · Kennedy Institute of Rheumatology Division, Imperial College School of Medicine, 1 Aspenlea Road, Hammersmith, London, UK. · Ann Rheum Dis. · Pubmed #11053090 links to  free full text

Abstract: The success of anti-tumour necrosis factor (TNF) treatment, either using antibodies or soluble receptors, has defined TNF as a major factor of the inflammatory response in rheumatoid arthritis (RA). As a result of this success, much attention has been devoted to understanding the molecular mechanisms by which TNF expression and activity is elicited and controlled. By understanding these pathways, it is hoped that key elements of the molecular pathology associated with RA will be uncovered and, as a result, new targets for therapeutic intervention will be identified. However, studying the cell and molecular biology of model systems for RA, such as primary human macrophages, or tissue from rheumatoid joints may present technical problems. In an attempt to overcome this, we have investigated the use of adenovirus as a means of delivering transgenes by which different intracellular pathways can be modulated and examined. Our data show that adenovirus can be successfully used to efficiently deliver transgenes to primary human macrophages and RA joint tissue. Using a virus encoding IkappaBalpha, the natural inhibitor of NFkappaB, we show that the requirement for the transcription factor is not universal, but is dependent on the nature of the stimulus. Furthermore, while NFkappaB is of importance for the expression of TNF and other pro-inflammatory cytokines (for example, interleukin 6) and the destructive matrix metalloproteinases, this factor is not required for the expression of anti-inflammatory cytokines interleukin 10 and interleukin 1 receptor antagonist.

Feldmann M, Bondeson J, Brennan FM, Foxwell BM, Maini RN. · Kennedy Institute of Rheumatology, 1 Aspenlea Road Hammersmith London W6 8LH. · Ann Rheum Dis. · Pubmed #10577970 links to  free full text

Abstract: Progress in understanding mechanisms of disease are necessary to usher in major changes in treatment. A new era in rheumatoid arthritis (RA) and related chronic autoimmune/inflammatory diseases is now beginning, with a variety of anti-TNFalpha treatments licensed for use in both RA and Crohn's disease. The rationale for this new treatment lies in an understanding that cytokines are critical, rate limiting molecules lying at the heart of the chronic autoimmune/inflammatory disease process. This understanding was developed from the critical evaluation of a hypothesis that was proposed linking cytokines, antigen presentation and autoimmunity in 1983. Detailed analysis focusing on the major site of the disease, the rheumatoid synovium was essential to developing indications that blockade of TNFalpha might be efficacious. This clue was validated using anti-TNFalpha treatment of an animal model of RA, murine collagen induced arthritis, and by immunohistochemical demonstration of upregulated TNF and TNF-R expression in the synovium. With this three pronged rationale, the authors were able to convince Centocor, Inc, which had developed a chimaeric anti-TNFalpha antibody for use in sepsis, to work with them to test the concept that TNFalpha blockade would be beneficial in RA. With the success of that first trial, other companies have subsequently tested their anti-TNF strategies successfully. Current interests extend to understanding the processes that regulate TNF production in the rheumatoid joint. Progress in this area is discussed, using adenoviruses to infect normal macrophages and rheumatoid synovium.

Sacre SM, Andreakos E, Kiriakidis S, Amjadi P, Lundberg A, Giddins G, Feldmann M, Brennan F, Foxwell BM. · Kennedy Institute of Rheumatology, Imperial College London, and the Department of Orthopedics, Royal United Hospital, Bath, UK. · Am J Pathol. · Pubmed #17255320 links to  free full text

Abstract: The widespread distribution of Toll-like receptors (TLRs) and their ligands raises the question whether they contribute to the production of inflammatory and tissue destructive molecules in rheumatoid arthritis (RA). We examined the expression and function of TLR2 and TLR4 and their downstream signaling adaptors MyD88 and Mal/TIRAP in synovial membrane cultures from RA tissue. Both TLR2 and TLR4 were detected by flow cytometry, and stimulation with TLR2 and TLR4 ligands augmented the spontaneous production of tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8, indicating that TLR2 and TLR4 are functional in these cultures. In addition, overexpression of dominant-negative forms of MyD88 and Mal/TIRAP significantly down-regulated the spontaneous production of cytokines tumor necrosis factor-alpha, IL-6, and vascular endothelial growth factor, and enzymes MMP-1, MMP-2, MMP-3, and MMP-13 in RA synovial membrane cell cultures. Because TLR2 and TLR4 require both MyD88 and Mal/TIRAP for signaling, this study suggests that TLR function may regulate the expression of these factors in the RA synovium. Conditioned media from synovial membrane cell cultures stimulated human macrophages in a MyD88- and Mal-dependent manner, suggesting the release of a TLR ligand(s) from these cells. Thus, TLRs not only protect against infection but may also promote the inflammatory and destructive process in RA.

Sacre SM, Lo A, Gregory B, Simmonds RE, Williams L, Feldmann M, Brennan FM, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology and Medicine, London, United Kingdom. · J Immunol. · Pubmed #19017992 No free full text.

Abstract: The advent of anti-TNF biologicals has been a seminal advance in the treatment of rheumatoid arthritis (RA) and has confirmed the important role of TNF in disease pathogenesis. However, it is unknown what sustains the chronic production of TNF. In this study, we have investigated the anti-inflammatory properties of mianserin, a serotonin receptor antagonist. We discovered mianserin was able to inhibit the endosomal TLRs 3, 7, 8, and 9 in primary human cells and inhibited the spontaneous release of TNF and IL-6 from RA synovial membrane cultures. This suggested a role for these TLRs in production of TNF and IL-6 from RA which was supported by data from chloroquine, an inhibitor of endosomal acidification (a prerequisite for TLRs 3, 7, 8, and 9 activation) which also inhibited production of these cytokines from RA synovial cultures. Only stimulation of TLR 3 or 8 induced TNF from these cultures, indicating that TLR7 and TLR9 were of less consequence in this model. The key observation that indicated the importance of TLR8 was the inhibition of spontaneous TNF production by imiquimod, which we discovered to be an inhibitor of TLR8. Together, these data suggest that TLR8 may play a role in driving TNF production in RA. Because this receptor can be inhibited by small m.w. molecules, it may prove to be an important therapeutic target.

Sumariwalla PF, Palmer CD, Pickford LB, Feldmann M, Foxwell BM, Brennan FM. · Kennedy Institute of Rheumatology, Imperial College London, London, UK. · Rheumatology (Oxford). · Pubmed #19015145 No free full text.

Abstract: OBJECTIVES: To evaluate the clinical efficacy of a novel synthetic peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist, CLX-090717, in several in vitro cell culture systems and murine CIA, an experimental model of RA. METHODS: Peripheral blood monocytes purified by elutriation, and rheumatoid synovial cells isolated from clinical tissue were cultured with CLX-090717 and TNF-alpha release was measured. Molecular mechanism of action was analysed by western blotting and electrophoretic mobility shift assay. Thioglycollate-elicited murine peritoneal macrophages were cultured with CLX-090717 and lipopolysaccharide (LPS)-induced TNF-alpha release was assayed. Therapeutic studies were done in mice with established arthritis by evaluating clinical parameters and histology. In addition, type II collagen response of lymphocytes from mice with CIA was examined. RESULTS: CLX-090717 significantly inhibited spontaneous TNF-alpha release by RA synovial membrane cells, as well as LPS-induced TNF-alpha release from human and murine monocytic cells. Inhibition of TNF-alpha in monocytes was mediated partially through a nuclear factor-kappaB (NF-kappaB)-dependent pathway, as judged by sustained levels of IkappaBalpha in cytosolic extracts and a reduced level of LPS-induced NF-kappaB activity in nuclear extracts. CLX-090717 reduced clinical signs of arthritis and damage to joint architecture when administered therapeutically to arthritic mice. Mechanisms of action in CIA involved the reduction in proliferation of arthritic lymphocytes to antigen in vitro as well as reduced TNF-alpha release. CONCLUSIONS: Our data suggest that the synthetic compound CLX-090717 has potential as a small molecular weight anti-inflammatory therapeutic for chronic inflammatory conditions.

Palmer CD, Mutch BE, Page TH, Horwood NJ, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, Charing Cross Campus, ARC Building, 65 Aspenlea Road, London W6 8LH, UK. · Biochem Biophys Res Commun. · Pubmed #18402776 No free full text.

Abstract: Discordant cytokine production is characteristic of chronic inflammatory conditions like rheumatoid arthritis (RA), and anti-cytokine therapeutics are becoming routinely used to treat RA in the clinic. Fibroblasts from rheumatoid synovium have been shown to contribute to cytokine production in inflamed joints; likewise these cells also produce cytokines in response to inflammatory mediators signalling through Toll like receptors (TLRs). Tyrosine kinase activity is essential to LPS-induced cytokine production, and we have previously implicated a role for the Tec kinase, Bmx, in inflammatory cytokine production. Here we show that Bmx kinase activity in RASF is increased following LPS stimulation and that Bmx is involved in the regulation of LPS-induced IL-6 and VEGF production via mRNA stabilisation. This is an important insight into the regulation of VEGF, which is involved in a wide range of different pathologies, and may lead to more effective design of novel anti-inflammatory/angiogenic therapeutics for conditions such as RA.

Palmer CD, Mutch BE, Workman S, McDaid JP, Horwood NJ, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, London, UK. · Blood. · Pubmed #18025155 links to  free full text

Abstract: Chronic inflammation, as seen in conditions such as rheumatoid arthritis and Crohn disease, is in part driven by discordant production of inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 (IL-6). Tyrosine kinase activity is essential to lipopolysaccharide-induced cytokine production in monocytes, and previous studies by us and others have implicated a role for the Tec kinase Bruton's tyrosine kinase (Btk) in inflammatory cytokine production. Here we show that knockdown of Btk using RNA interference results in decreased tumor necrosis factor-alpha, but not IL-6 production. Further investigations into the signaling mechanisms regulating IL-6 production led to the discovery that the Tec kinase bone marrow tyrosine kinase gene in chromosome X (Bmx) regulates Toll-like receptor-induced IL-6 production. Our data further showed that Bmx-dependent super-induction of IL-6 does not involve nuclear factor-kappaB activity. More detailed investigations of pathways downstream of Bmx signaling revealed that Bmx targets the IL-6 3' untranslated region to increase mRNA stabilization via a novel, thus far undefined, p38 mitogen activated protein kinase-independent pathway. These data have important implications for the design of therapeutics targeted against specific cytokines and their regulators in inflammatory disease.

Lundberg AM, Drexler SK, Monaco C, Williams LM, Sacre SM, Feldmann M, Foxwell BM. · Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College of Science, Technology, and Medicine, 1 Aspenlea Road, Hammersmith, London, United Kingdom. · Blood. · Pubmed #17660379 links to  free full text

Abstract: TLR3 recognizes double-stranded RNA, a product associated with viral infections. Many details of TLR3-induced mechanisms have emerged from gene-targeted mice or inhibition studies in transformed cell lines. However, the pathways activated in human immune cells or cells from disease tissue are less well understood. We have investigated TLR3-induced mechanisms of human primary cells of the innate immune system, including dendritic cells (DCs), macrophages (MØs), endothelial cells (ECs), and synovial fibroblasts isolated from rheumatoid arthritis joint tissue (RA-SFs). Here, we report that while these cells all express TLR3, they differ substantially in their response to TLR3 stimulation. The key antiviral response chemokine IP-10 was produced by all cell types, while DCs and MØs failed to produce the proinflammatory cytokines TNFalpha and IL-6. Unexpectedly, TNFalpha was found secreted by TLR3-stimulated RA-SF. Furthermore, TLR3 stimulation did not activate NFkappaB, MAPKs, or IRF-3 in DCs and MØs, but was able to do so in ECs and RA-SF. These findings were specific for human cells, thereby revealing a complexity not previously expected. This is the first report of such cell type- and species-specific response for any TLR stimulation and helps to explain important difficulties in correlating murine models of inflammatory diseases and human inflammation.

Edwards CJ, Feldman JL, Beech J, Shields KM, Stover JA, Trepicchio WL, Larsen G, Foxwell BM, Brennan FM, Feldmann M, Pittman DD. · The Kennedy Institute of Rheumatology Division, Imperial College School of Medicine, London, UK. · Mol Med. · Pubmed #17515956 links to  free full text

Abstract: Rheumatoid arthritis (RA) is a chronic inflammatory arthritis. Currently, diagnosis of RA may take several weeks, and factors used to predict a poor prognosis are not always reliable. Gene expression in RA may consist of a unique signature. Gene expression analysis has been applied to synovial tissue to define molecularly distinct forms of RA; however, expression analysis of tissue taken from a synovial joint is invasive and clinically impractical. Recent studies have demonstrated that unique gene expression changes can be identified in peripheral blood mononuclear cells (PBMCs) from patients with cancer, multiple sclerosis, and lupus. To identify RA disease-related genes, we performed a global gene expression analysis. RNA from PBMCs of 9 RA patients and 13 normal volunteers was analyzed on an oligonucleotide array. Compared with normal PBMCs, 330 transcripts were differentially expressed in RA. The differentially regulated genes belong to diverse functional classes and include genes involved in calcium binding, chaperones, cytokines, transcription, translation, signal transduction, extracellular matrix, integral to plasma membrane, integral to intracellular membrane, mitochondrial, ribosomal, structural, enzymes, and proteases. A k-nearest neighbor analysis identified 29 transcripts that were preferentially expressed in RA. Ten genes with increased expression in RA PBMCs compared with controls mapped to a RA susceptibility locus, 6p21.3. These results suggest that analysis of RA PBMCs at the molecular level may provide a set of candidate genes that could yield an easily accessible gene signature to aid in early diagnosis and treatment.

Beech JT, Andreakos E, Ciesielski CJ, Green P, Foxwell BM, Brennan FM. · Kennedy Institute of Rheumatology Division, Imperial College School of Medicine, 1 Aspenlea Road, Hammersmith, London W6 8LH, UK. · Arthritis Res Ther. · Pubmed #17101049 links to  free full text

Abstract: We and others have reported that rheumatoid arthritis (RA) synovial T cells can activate human monocytes/macrophages in a contact-dependent manner to induce the expression of inflammatory cytokines, including tumour necrosis factor alpha (TNFalpha). In the present study we demonstrate that RA synovial T cells without further activation can also induce monocyte CC and CXC chemokine production in a contact-dependent manner. The transcription factor NFkappaB is differentially involved in this process as CXC chemokines but not CC chemokines are inhibited after overexpression of IkappaBalpha, the natural inhibitor of NFkappaB. This effector function of RA synovial T cells is also shared by T cells activated with a cytokine cocktail containing IL-2, IL-6 and TNFalpha, but not T cells activated by anti-CD3 cross-linking that mimics TCR engagement. This study demonstrates for the first time that RA synovial T cells as well as cytokine-activated T cells are able to induce monocyte chemokine production in a contact-dependent manner and through NFkappaB-dependent and NFkappaB-independent mechanisms, in a process influenced by the phosphatidyl-inositol-3-kinase pathway. Moreover, this study provides further evidence that cytokine-activated T cells share aspects of their effector function with RA synovial T cells and that their targeting in the clinic has therapeutic potential.

Campbell J, Ciesielski CJ, Hunt AE, Horwood NJ, Beech JT, Hayes LA, Denys A, Feldmann M, Brennan FM, Foxwell BM. · Kennedy Institute of Rheumatology Division, Imperial College School of Medicine Hammersmith, London, United Kingdom. · J Immunol. · Pubmed #15557189 links to  free full text

Abstract: TNF-alpha is a key factor in a variety of inflammatory diseases. This study examines the role of p38 MAPK in the regulation of TNF-alpha in primary human cells relevant to inflammation, e.g., macrophages and rheumatoid synovial cells. Using a dominant negative variant (D168A) of p38 MAPK and a kinase inhibitor, SB203580, we confirm in primary human macrophages that p38 MAPK regulates TNF-alpha production using a posttranscriptional mechanism requiring the 3' untranslated region of the gene. However, in LPS-activated primary human macrophages we also detect a second previously unidentified mechanism, the p38 MAPK modulation of TNF-alpha transcription. This is mediated through p38 MAPK regulation of NF-kappaB. Interestingly this mechanism was not observed in rheumatoid synovial cells. Importantly however, the dominant negative mutant of p38 MAPK, but not SB203580 was effective at inhibiting spontaneous TNF-alpha production in these ex vivo rheumatoid synovial cell cultures. These data indicate there are potential major differences in the role of p38 MAPK in inflammatory signaling that have a bearing on the use of this kinase as a target for therapy. These results indicate despite disappointing results with p38 MAPK inhibitors in the clinic, this kinase is a valid target in rheumatoid disease.

Andreakos E, Smith C, Kiriakidis S, Monaco C, de Martin R, Brennan FM, Paleolog E, Feldmann M, Foxwell BM. · Kennedy Institute of Rheumatology, Imperial College of Science, Technology and Medicine, London, UK. · Arthritis Rheum. · Pubmed #12847684 links to  free full text

Abstract: OBJECTIVE: To investigate the potential role of IkappaB kinase 1 (IKK-1) and IKK-2 in the regulation of nuclear factor kappaB (NF-kappaB) activation and the expression of tumor necrosis factor alpha (TNFalpha), as well as interleukin-1beta (IL-1beta), IL-6, IL-8, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs), in rheumatoid arthritis (RA). METHODS: Recombinant adenoviruses expressing beta-galactosidase, dominant-negative IKK-1 and IKK-2, or IkappaBalpha were used to infect ex vivo RA synovial membrane cultures and synovial fibroblasts obtained from patients with RA undergoing joint replacement surgery, or human dermal fibroblasts, human umbilical vein endothelial cells (HUVECs), and monocyte-derived macrophages from healthy volunteers. Then, their effect on the spontaneous or stimulus-induced release of inflammatory cytokines, VEGF, and MMPs from RA synovial membrane cells was examined. RESULTS: IKK-2 was not required for lipopolysaccharide (LPS)-induced NF-kappaB activation or TNFalpha, IL-6, or IL-8 production in macrophages, but was essential for this process in response to CD40 ligand, TNFalpha, and IL-1. In synovial fibroblasts, dermal fibroblasts, and HUVECs, IKK-2 was also required for LPS-induced NF-kappaB activation and IL-6 or IL-8 production. In RA synovial membrane cells, IKK-2 inhibition had no effect on spontaneous TNFalpha production but significantly reduced IL-1beta, IL-6, IL-8, VEGF, and MMPs 1, 2, 3, and 13. CONCLUSION: Our study demonstrates that IKK-2 is not essential for TNFalpha production in RA. However, because IKK-2 regulates the expression of other inflammatory cytokines (IL-1beta, IL-6, and IL-8), VEGF, and MMPs 1, 2, 3, and 13, which are involved in the inflammatory, angiogenic, and destructive processes in the RA joint, it may still be a good therapeutic target.

Brennan FM, Hayes AL, Ciesielski CJ, Green P, Foxwell BM, Feldmann M. · Chester Beatty Laboratories, Institute of Cancer Research, London, UK. · Arthritis Rheum. · Pubmed #11822409 links to  free full text

Abstract: OBJECTIVE: To investigate the mechanism that leads to the spontaneous production of tumor necrosis factor alpha (TNFalpha) in rheumatoid arthritis (RA) synovial tissue. METHODS: Normal blood monocytes were cocultured either with fixed activated T cells generated from normal blood or RA synovial T cells purified from synovium. TNFalpha production was measured in supernatants from these cocultures following blockade of the transcription factor nuclear factor kappaB (NF-kappaB) using adenoviral transfer of the inhibitor of NF-kappaB kinase alpha into the responding monocytes, or blockade of phosphatidylinositol 3-kinase (PI 3-kinase) using the inhibitory drugs wortmannin or LY294002. TNFalpha production was measured by enzyme-linked immunosorbent assay. RESULTS: TNFalpha production in synovial tissue from patients with RA but not osteoarthritis was found to be T cell dependent. The RA synovial joint T cells resembled normal T cells that had been activated for 8 days using a cocktail of cytokines. These T cells, designated Tck (cytokine-activated T cells), and RA synovial T cells both induced TNFalpha production in resting monocytes in a cell-contact-dependent manner, which was abrogated by blockage of the transcription factor NF-kappaB but augmented if PI 3-kinase was inhibited. Normal blood T cells activated conventionally via the T cell receptor with crosslinked anti-CD3 antibody resulted in TNFalpha production from monocytes; this was unaffected by NF-kappaB blockade, but was inhibited in the presence of PI 3-kinase-blocking drugs. CONCLUSION: These data provide strong evidence for the importance of T cells in inducing TNFalpha in chronic inflammatory rheumatoid tissue, and give insight into the mechanism whereby these T cells are activated in vivo. Furthermore, they indicate that production of TNFalpha in pathologic tissue is regulated differently from physiologic antigen-dependent TNFalpha production, which raises the possibility that selective inhibitors of TNFalpha in disease may be developed.