An explorative study on proteomic analyses related to inflammation and pain in children with juvenile idiopathic arthritis

BACKGROUND

Our aim was attempting to find proteins involved in the pain process and correlating with pain but not degree of inflammation in children with juvenile idiopathic arthritis (JIA), using a proteomics panel.

METHODS

A total of 87 plasma samples were collected from 51 children with JIA (51 at diagnosis in a higher disease activity state, 18 at follow-up in a lower disease activity state) and 18 healthy controls. Relative levels of 92 proteins related to a wide range of biological processes in inflammation were obtained using a proximity extension assay panel. Comparisons between children with and without JIA, in different disease categories, by juvenile disease activity score (JADAS27) and degree of pain on a visual analogue scale (VAS), were performed using parametric and non-parametric statistical methods.

RESULTS

Nineteen proteins involved in arthritic inflammation, such as interleukin 6 (IL-6) and S100 protein A12, were higher in patients with JIA than controls, seven decreased significantly during treatment, and 18 correlated significantly with JADAS27. Three proteins correlated with pain VAS scores in unadjusted analyses: the glial cell line-derived neurotrophic factor (GDNF), transforming growth factor beta, and IL-18R1. Levels of GDNF correlated significantly with pain VAS scores but not with JADAS27.

CONCLUSIONS

Plasma levels of 18 of 92 tested proteins correlated with degree of disease activity. Levels of three proteins correlated with pain, and levels of one, GDNF, originating from neural cells, correlated with pain without correlating with inflammatory degree, suggesting that it may play a role in pain in JIA. Further studies in larger cohorts are warranted.

CCL13 and human diseases

CCL13/MCP-4 belongs to the CC chemokine family, which induces chemotaxis in many immune cells. Despite extensive research into its function in numerous disorders, a thorough analysis of CCL13 is not yet accessible. The role of CCL13 in human disorders and existing CCL13-focused therapies are outlined in this study. The function of CCL13 in rheumatic diseases, skin conditions, and cancer is comparatively well-established, and some studies also suggest that it may be involved in ocular disorders, orthopedic conditions, nasal polyps, and obesity. We also give an overview of research that found very little evidence of CCL13 in HIV, nephritis, and multiple sclerosis. Even though CCL13-mediated inflammation is frequently linked to disease pathogenesis, it's fascinating to note that in some conditions, like primary biliary cholangitis (PBC) and suicide, it might even act as a preventative measure.

Novel Insights Into Rheumatoid Arthritis Through Characterization of Concordant Changes in DNA Methylation and Gene Expression in Synovial Biopsies of Patients With Differing Numbers of Swollen Joints

In this study, we sought to characterize synovial tissue obtained from individuals with arthralgia and disease-specific auto-antibodies and patients with established rheumatoid arthritis (RA), by applying an integrative multi-omics approach where we investigated differences at the level of DNA methylation and gene expression in relation to disease pathogenesis. We performed concurrent whole-genome bisulphite sequencing and RNA-Sequencing on synovial tissue obtained from the knee and ankle from 4 auto-antibody positive arthralgia patients and thirteen RA patients. Through multi-omics factor analysis we observed that the latent factor explaining the variance in gene expression and DNA methylation was associated with Swollen Joint Count 66 (SJC66), with patients with SJC66 of 9 or more displaying separation from the rest. Interrogating these observed differences revealed activation of the immune response as well as dysregulation of cell adhesion pathways at the level of both DNA methylation and gene expression. We observed differences for 59 genes in particular at the level of both transcript expression and DNA methylation. Our results highlight the utility of genome-wide multi-omics profiling of synovial samples for improved understanding of changes associated with disease spread in arthralgia and RA patients, and point to novel candidate targets for the treatment of the disease.

STAT3 Mediates the Differential Effects of Oncostatin M and TNFα on RA Synovial Fibroblast and Endothelial Cell Function

Objectives: Oncostatin M (OSM), a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family, has been implicated in the pathogenesis of autoimmune diseases. Here we investigate the mechanisms by which its synergistic interactions with TNFα regulate the cellular bioenergetics and invasive function of synovial cells from patients with Rheumatoid Arthritis. Methods: Primary RA synovial fibroblasts (RAFLS) and human umbilical vein endothelial cells (HUVEC) were cultured with OSM alone or in combination with TNFα. Pro-inflammatory cytokines, angiogenic growth factors and adhesion molecules were quantified by real-time PCR and ELISA. Invasion, angiogenesis and cellular adhesion were quantified by Transwell invasion chambers, Matrigel tube formation assays, and adhesion binding assays. Cellular bioenergetics was assessed using the Seahorse XFe96 Analyser. Key metabolic genes (GLUT-1, HK2, PFKFB3, HIF1α, LDHA, PKM2) and transcription factor STAT3 were measured using real-time PCR and western blot. Results: OSM differentially regulates pro-inflammatory mediators in RAFLS and HUVEC, with IL-6, MCP-1, ICAM-1, and VEGF all significantly induced, in contrast to the observed inhibition of IL-8 and GROα, with opposing effects observed for VCAM-1 depending on cell type. Functionally, OSM significantly induced angiogenic network formation, adhesion, and invasive mechanisms. This was accompanied by a change in the cellular bioenergetic profile of the cells, where OSM significantly increased the ECAR/OCR ratio in favor of glycolysis, paralleled by induction of the glucose transporter GLUT-1 and key glycolytic enzymes (HK2, PFKFB3, HIF1α). OSM synergizes with TNFα to differentially regulate pro-inflammatory mechanisms in RAFLS and HUVEC. Interestingly, OSM differentially synergizes with TNFα to regulate metabolic reprogramming, where induction of glycolytic activity with concomitant attenuation of mitochondrial respiration and ATP activity was demonstrated in RAFLS but not in HUVEC. Finally, we identified a mechanism, whereby the combination of OSM with TNFα induces transcriptional activity of STAT3 only in RAFLS, with no effect observed in HUVEC. Conclusion: STAT3 mediates the differential effects of OSM and TNFα on RAFLS and EC function. Targeting OSM or downstream signaling pathways may lead to new potential therapeutic or adjuvant strategies, particularly for those patients who have sub-optimal responses to TNFi.

GADD45a and GADD45b Genes in Rheumatoid Arthritis and Systemic Lupus Erythematosus Patients

Background: GADD45 genes are stress sensors in response to cellular stress response, activated signal pathways leading to the stimulation of inflammatory cytokines. This study is to examine the associations of GADD45a and GADD45b genes with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients. Methods: 230 patients of RA, 140 patients of SLE, and 191 healthy controls were enrolled. Genomic DNA was extracted from peripheral blood mononuclear cells and gene polymorphisms were genotyped by TaqMan assay. RNA expression was quantitated with real-time polymerase chain reaction. Results: The RNA expression of the GADD45b gene was significantly lower in RA patients than the control cases (p = 0.03). The odds ratio of GADD45a genotype -589 CC (rs581000) was significantly low (OR = 0.36, 95% CI, 0.15–0.87) in DR4-negative RA patients. The odds ratio of GADD45b genotype -712CT (rs3795024) in DR4-negative RA patients was 0.41 (95% CI, 0.18–0.95). In clinical manifestation, the odds ratio of GADD45b -712CT genotype with anti-RNP antibody was 4.14 (95% CI, 1.10–15.63) in SLE patients. GADD45a genotype -589GG+GC was associated with rheumatoid factor (RF) in SLE patients. Conclusions: Genotypes GADD45a -589CC and GADD45b -712CT were shown to be less susceptible to RA and related to the disease state in SLE patients.

Coordination of Immune-Stroma Crosstalk by IL-6 Family Cytokines

Stromal cells are a subject of rapidly growing immunological interest based on their ability to influence virtually all aspects of innate and adaptive immunity. Present in every bodily tissue, stromal cells complement the functions of classical immune cells by sensing pathogens and tissue damage, coordinating leukocyte recruitment and function, and promoting immune response resolution and tissue repair. These diverse roles come with a price: like classical immune cells, inappropriate stromal cell behavior can lead to various forms of pathology, including inflammatory disease, tissue fibrosis, and cancer. An important immunological function of stromal cells is to act as information relays, responding to leukocyte-derived signals and instructing leukocyte behavior in kind. In this regard, several members of the interleukin-6 (IL-6) cytokine family, including IL-6, IL-11, oncostatin M (OSM), and leukemia inhibitory factor (LIF), have gained recognition as factors that mediate crosstalk between stromal and immune cells, with diverse roles in numerous inflammatory and homeostatic processes. This review summarizes our current understanding of how IL-6 family cytokines control stromal-immune crosstalk in health and disease, and how these interactions can be leveraged for clinical benefit.

An initial investigation into endothelial CC chemokine expression in the human rheumatoid synovium

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Comparison of the presence of 26 of the CC-chemokines in RA synovial ECs.

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The chemokines CCL7, CCL14, CCL16 and CCL22 were established as being present at RA synovial ECs for the first time.

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CCL8, CCL14, CCL19 and CCL22 are significantly increased in RA compared to non-RA.

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Synovial fluid CCL7 may be a novel RA disease marker.

Rheumatoid arthritis (RA) is a destructive and chronic autoimmune inflammatory disease. Synovial inflammation is a major feature of RA and is associated with leukocyte recruitment. Leukocytes cross the endothelial cells (ECs) into the synovial tissue and fluid and this migration is mediated via a range of chemokines and adhesion molecules on the ECs. As important mediators of leukocyte extravasation, a number of chemokines from each of the chemokine families have been established as expressed in the RA joint.

However, as little information is available on which chemokines are expressed/presented by the ECs themselves, the purpose of the study was to ascertain which of the CC chemokines were localised in RA ECs.

Immunofluoresence was used to assess the presence of the CC-family chemokines in RA synovial ECs using von-Willebrand factor (VWF) as a pan-endothelial marker and a range of human chemokine antibodies. The percentage of VWF positive vessels which were positive for the chemokines was determined. The presence of the four most highly expressed novel chemokines were further investigated in non-RA synovial ECs and the sera and synovial fluid (SF) from patients with RA and osteoarthritis (OA). Statistical analysis of immunofluorescence data was carried out by Student’s t-test. For analysis of ELISA data, Kruskal-Wallis ANOVA followed by Dunn’s multiple comparison test was utilised to analyse differences in sera and SF levels for each chemokine between RA and OA. Spearman rank correlations of sera and SF chemokine levels with a range of clinical variables were also performed.

Chemokine detection varied, the least abundant being CCL27 which was present in 8.3% of RA blood vessels and the most abundant being CCL19 which was present in 80%. Of the 26 chemokines studied, 19 have not been previously observed in RA ECs. Four of these novel chemokines, namely CCL7, CCL14, CCL16 and CCL22 were present on ≥60% of vessels. CCL14 and CCL22 were shown to be increased in RA ECs compared to non-RA ECs, p = 0.0041 and p = 0.014 respectively. EC chemokines CCL7, CCL14, CCL16 and CCL22 also occurred in RA synovial fluid and sera as established by ELISA. CCL7 was shown to be significantly increased in sera and SF from RA patients compared to that from osteoarthritis (OA) patients (p < 0.01), and to have a highly significant correlation with the level of anti-CCP (R = 0.93, p = 0.001). Less abundant chemokines shown to be present in RA ECs were CCL1-3, CCL5, CCL10-13, CCL15, CCL17, CCL18, CCL20, CCL21 and CCL23-28.

In conclusion, this initial study is the first to show the presence of a number of CC chemokines in RA ECs. It provides evidence that further validation and investigation into the presence and functionality of these novel chemokines expressed at RA synovial ECs may be warranted.

The barrier hypothesis and Oncostatin M: Restoration of epithelial barrier function as a novel therapeutic strategy for the treatment of type 2 inflammatory disease

Mucosal epithelium maintains tissue homeostasis through many processes, including epithelial barrier function, which separates the environment from the tissue. The barrier hypothesis of type 2 inflammatory disease postulates that epithelial and epidermal barrier dysfunction, which cause inappropriate exposure to the environment, can result in allergic sensitization and development of type 2 inflammatory disease. The restoration of barrier dysfunction once it's lost, or the prevention of barrier dysfunction, have the potential to be exciting new therapeutic strategies for the treatment of type 2 inflammatory disease. Neutrophil-derived Oncostatin M has been shown to be a potent disrupter of epithelial barrier function through the induction of epithelial-mesenchymal transition (EMT). This review will discuss these events and outline several points along this axis at which therapeutic intervention could be beneficial for the treatment of type 2 inflammatory diseases.

Oncostatin M drives intestinal inflammation and predicts response to tumor necrosis factor-neutralizing therapy in patients with inflammatory bowel disease

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex chronic inflammatory conditions of the gastrointestinal tract that are driven by perturbed cytokine pathways. Anti-tumor necrosis factor-α (TNF) antibodies are mainstay therapies for IBD. However, up to 40% of patients are nonresponsive to anti-TNF agents, which makes the identification of alternative therapeutic targets a priority. Here we show that, relative to healthy controls, inflamed intestinal tissues from patients with IBD express high amounts of the cytokine oncostatin M (OSM) and its receptor (OSMR), which correlate closely with histopathological disease severity. The OSMR is expressed in nonhematopoietic, nonepithelial intestinal stromal cells, which respond to OSM by producing various proinflammatory molecules, including interleukin (IL)-6, the leukocyte adhesion factor ICAM1, and chemokines that attract neutrophils, monocytes, and T cells. In an animal model of anti-TNF-resistant intestinal inflammation, genetic deletion or pharmacological blockade of OSM significantly attenuates colitis. Furthermore, according to an analysis of more than 200 patients with IBD, including two cohorts from phase 3 clinical trials of infliximab and golimumab, high pretreatment expression of OSM is strongly associated with failure of anti-TNF therapy. OSM is thus a potential biomarker and therapeutic target for IBD, and has particular relevance for anti-TNF-resistant patients.

[Fibroblasts as pathogenic cells in rheumatic inflammation]

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovitis, synovial hyperplasia and progressive degeneration of affected joints. These processes are mediated by cells of the immune system as well as by synovial fibroblasts (RASF) originating from the lining layer of the synovium. In this scenario RASFs display an activated phenotype: they show an altered expression of adhesion molecules which allows attachment to articular cartilage and by synthesis of proteases they mediate progressive cartilage and bone destruction. Furthermore, they produce various cytokines and chemokines, which are essential for promoting the inflammatory response. In recent years it has become evident that RASFs not only passively respond to the proinflammatory milieu in the joints of RA patients but also actively contribute by the overproduction of several cytokines and chemokines. These proinflammatory cytokines trigger the transformation of RASFs into an aggressive and invasive phenotype. Additionally, the primarily altered genuine RASFs are actively involved in the recruitment and activation of immune cells. Taken together, they are key players in the development of the well-known chronic, destructive inflammatory response in joints affected by RA.

Osteopontin Promotes Oncostatin M Production in Human Osteoblasts: Implication of Rheumatoid Arthritis Therapy

Accumulating evidence indicates that subchondral bone might play an essential role in rheumatoid arthritis (RA). Osteopontin (OPN) induces the production of an important proinflammatory cytokine involved in the pathogenesis of RA. This study evaluated the activation of oncostatin M (OSM) by OPN in human primary osteoblasts to understand RA pathogenesis and characterized the intracellular signaling pathways involved in this activation. Quantitative PCR, ELISA, and Western blot results indicated that stimulation of human primary osteoblasts with OPN induces OSM expression through αvβ3 integrin/c-Src/platelet-derived growth factor receptor transactivation/MEK/ERK. Treatment of osteoblasts with OPN also increased c-Jun phosphorylation, AP-1 luciferase activity, and c-Jun binding to the AP-1 element on the OSM promoter, as demonstrated using chromatin immunoprecipitation assay. Moreover, inhibition of OPN expression using lentiviral-OPN short hairpin RNA resulted in the amelioration of articular swelling, cartilage erosion, and OSM expression in the ankle joint of mice with collagen-induced arthritis as shown using microcomputed tomography and immunohistochemistry staining. Our results imply that OSM expression in osteoblasts increases in response to OPN-induced inflammation in vitro. Finally, lentiviral-OPN short hairpin RNA ameliorates the inflammatory response and bone destruction in mice with collagen-induced arthritis. Therefore, OPN may be a potential therapeutic target for RA.

New treatments for inflammatory rheumatic disease

As our understanding of the pathogenesis of autoimmune diseases is growing, new therapies are being developed to target disease-specific pathways. Since the introduction of etanercept in 1998, several biotechnological agents have been developed, most of them indicated in the treatment of rheumatoid arthritis, but also psoriatic arthritis. Most currently available molecules target TNF-alfa with different strategies (i.e., etanercept, infliximab, adalimumab, golimumab, and certolizumab pegol), IL-6 (tocilizumab), CTLA-4 (abatacept), and B cells (rituximab, belimumab) as they are key mediators in the cascade of inflammation. Further, small molecules have been recently developed to target intracellular signaling, such as Janus Kinases for tofacitinib, the first FDA-approved small molecule for rheumatoid arthritis. Most novel treatments are being developed for arthritis with specific differences between rheumatoid and psoriatic arthritis, as well as for systemic lupus erythematosus, following the approval of belimumab. Finally, biologic therapies are effective also in gout, mainly targeting interleukin-1 to block the inflammasome. This review article describes the new and upcoming treatment options for rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and gout to dissect what we should be aware of when discussing these new and promising molecules.

Intratumoural inflammation and endocrine resistance in breast cancer

It is becoming clear that inflammation-associated mechanisms can affect progression of breast cancer and modulate responses to treatment. Estrogen receptor alpha (ERα (ESR1)) is the principal biomarker and therapeutic target for endocrine therapies in breast cancer. Over 70% of patients are ESR1-positive at diagnosis and are candidates for endocrine therapy. However, ESR1-positive tumours can become resistant to endocrine therapy. Multiple mechanisms of endocrine resistance have been proposed, including suppression of ESR1. This review discusses the relationship between intratumoural inflammation and endocrine resistance with a particular focus on inflammation-mediated suppression of ESR1.

Oncostatin M regulates SOCS3 mRNA stability via the MEK-ERK1/2-pathway independent of p38(MAPK)/MK2

The induction of suppressor of cytokine signalling (SOCS)3 expression context dependently involves regulation of SOCS3 transcript stability as previously demonstrated for MAPK activated protein kinase (MK)2-dependent regulation of SOCS3 expression by TNFα (Ehlting et al., 2007). In how far the IL-6-type cytokine OSM, which in contrast to IL-6 is a strong activator of p38(MAPK)/MK2 signalling, also involves regulation of transcript stability and activation of MK2 to induce SOCS3 expression is unclear. In contrast to IL-6, OSM induces SOCS3 expression in murine fibroblasts and in primary human and murine hepatocytes, but not in macrophages because the latter lack the OSM receptor (OSMR)β subunit. Evidence is provided that regulation of OSM-induced expression of SOCS3 involves MEK1- and Erk1/2-mediated stabilization of the SOCS3 transcript. Consistently, OSM-induced stabilization of the SOCS3 transcript is impaired in the presence of inhibitors that specifically block activation of MEK1/2 (U0126) and ERK1/2 (FR180204) or upon knock-down of ERK1/2 expression using specific siRNA. As a potential target site that integrates the stability regulating effect of OSM and OSM-induced activation of MEK1/2 and ERK1/2 a region containing three copies of a pentameric AUUUA motif located within position 2422 and 2541 in closed proximity to the 3' UTR of the SOCS3 transcript has been identified. Unexpectedly, activation of the p38(MAPK)/MK2 pathway, which apart from STAT3 and ERK1/2, is also strongly activated by OSM in human and murine hepatocytes and murine fibroblasts is dispensable for stabilization of the SOCS3 transcript as suggested from inhibitor studies using the p38(MAPK) inhibitor SB203580 or from the analysis of MK2-deficient hepatocytes. However, analysis of MK2-deficient macrophages and hepatocytes revealed that, although MK2 is dispensable for regulation of OSM-induced SOCS3 expression, MK2 is essential for LPS-induced OSM production in macrophages and limits the overall availability of the OSMRβ subunit in hepatocytes. Thus MK2 plays a role for the induction and sensing of OSM-mediated intercellular signalling between macrophages and hepatocytes during LPS-induced inflammation.

The enigmatic cytokine oncostatin m and roles in disease

Oncostatin M is a secreted cytokine involved in homeostasis and in diseases involving chronic inflammation. It is a member of the gp130 family of cytokines that have pleiotropic functions in differentiation, cell proliferation, and hematopoetic, immunologic, and inflammatory networks. However, Oncostatin M also has activities novel to mediators of this cytokine family and others and may have fundamental roles in mechanisms of inflammation in pathology. Studies have explored Oncostatin M functions in cancer, bone metabolism, liver regeneration, and conditions with chronic inflammation including rheumatoid arthritis, lung and skin inflammatory disease, atherosclerosis, and cardiovascular disease. This paper will review Oncostatin M biology in a historical fashion and focus on its unique activities, in vitro and in vivo, that differentiate it from other cytokines and inspire further study or consideration in therapeutic approaches.

Therapeutic targeting of the oncostatin M receptor-β prevents inflammatory heart failure

Heart failure (HF) is a common and potentially deadly condition, which frequently develops as a consequence of various diseases of the heart. The incidence of heart failure continuously increases in aging societies illustrating the need for new therapeutic approaches. We recently discovered that continuous activation of oncostatin M (OSM), a cytokine of the interleukin-6 family that induces dedifferentiation of cardiomyocytes, promotes progression of heart failure in dilative cardiomyopathy. To evaluate whether inhibition of OSM signaling represents a meaningful therapeutic approach to prevent heart failure we attenuated OSM-receptor (Oβ) signaling in a mouse model of inflammatory dilative cardiomyopathy. We found that administration of an antibody directed against the extracellular domain of Oβ or genetic inactivation of a single allele of the Oβ gene reduced cardiomyocyte remodeling and dedifferentiation resulting in improved cardiac performance and increased survival. We conclude that pharmacological attenuation of long-lasting Oβ signaling is a promising strategy to treat different types and stages of HF that go along with infiltration by OSM-releasing inflammatory cells.

Association of OSMR gene polymorphisms with rheumatoid arthritis and systemic lupus erythematosus patients

Cytokines are involved in the pathogenesis of autoimmune diseases. Oncostatin M receptor (OSMR) activates JAK/STAT and MAPK pathways leading to the stimulation of a variety of cytokines and inflammatory substances. Many pro-inflammatory cytokines are involved in the inflammatory process of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). In this study, we carried out experiments to examine the relationship of OSMR promoter polymorphisms with RA and SLE patients. 241 patients of RA, 143 patients of SLE and 203 healthy controls were enrolled in their recruitment from the Kaohsiung Medical University Hospital. Genomic DNA was extracted from peripheral blood mononuclear cells and gene polymorphism was genotyped by TaqMan real-time polymerase chain reaction. The OMSR promoter region -100 G/T (rs22922016) genotype was in no relation to the susceptibility of RA, but -100 T/T (rs22922016) genotype could prevent the patients with sicca syndrome and the existence of anti-Ro antibodies. In contrast, the -100 G/T+T/T (rs22922016) genotypes were significantly associated with an increased risk of SLE (odds ratio, OR=1.62, 95% confidence interval (CI), 1.01-2.62). 94.38% of SLE patients with arthritis were belonged to the -1687C/C (rs540558) genotype. The T allele of promoter region -100 T/T (rs22922016) has protective effect and could ameliorate the disease condition in RA patients, whereas the same T allele was a risk allele in the susceptibility of SLE. The disease severity of rheumatoid arthritis and systemic lupus erythematosus can be partially affected by the OSMR promoter polymorphisms.

Safety, tolerability, pharmacokinetics and pharmacodynamics of an anti- oncostatin M monoclonal antibody in rheumatoid arthritis: results from phase II randomized, placebo-controlled trials

Introduction

Oncostatin M (OSM) has been implicated in the pathophysiology of rheumatoid arthritis (RA) through its effect on inflammation and joint damage. GSK315234 is a humanised anti-OSM Immunoglobulin G1 (IgG1) monoclonal antibody (mAb). This 3-part study examines the safety, tolerability and efficacy of GSK315234 in patients with active RA.

Method

This was a 3-part (Parts A, B and C), multicenter study. Part A and Part B were randomised, double-blind, placebo-controlled, Bayesian adaptive dose finding studies to investigate the safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of single (Part A) and 3 repeat (Part B) intravenous infusions of GSK315234 in patients with active RA on a background of methotrexate (MTX). Part C was a single dose, randomised, single-blind, placebo-controlled study to assess subcutaneously administered GSK315234 to patients with active RA on a background of MTX.

Result

The primary endpoint of the study was mean change in DAS28 at Day 28 in Part A and Day 56 in Part B and C. All patients receiving at least one dose of GSK315234 were included in safety analysis. In Part A, there were statistically significant differences in DAS28 between 3 mg/kg and placebo at Day 56, 84 and 91. There was also a statistically significant difference in DAS28 between 0.3 mg/kg, 3 mg/kg and 10 mg/kg, as compared to placebo, at Day 84. Although these changes were small and occurred late, they supported progression to Part B and C to determine the therapeutic potential of GSK315234. For Part B, no significant difference was observed between 6 mg/kg and placebo. For Part C, a statistically significant difference in DAS28 was observed at Day 40, Day 84 and Day 100 between the 500 mg subcutaneous group, as compared to placebo. No significant findings were observed at any of the time points for EULAR response criteria, ACR20, ACR50 or ACR70. An exploratory analysis of clinical, pharmacokinetic and pharmacodynamics data suggests the lack of efficacy may be due to moderate binding affinity and rapid off-rate of GSK315234 as compared to the higher affinity OSM receptor causing a protein carrier effect prolonging the half life of OSM due to accumulation of the OSM/antibody complex in the serum and synovial fluid.

Conclusion

Our data highlighted the importance of binding affinity and off-rate effect of a mAb to fully neutralize the target and how this may influence its efficacy and potentially worsen disease activity. Using an anti-OSM mAb with high affinity should test this hypothesis and examine the potential of OSM as a therapeutic target in RA.

Trial registration

ClinicalTrials.gov no: NCT00674635

The multiple faces of CCL13 in immunity and inflammation

CCL13/MCP-4, is a CC family chemokine that is chemoattractant for eosinophils, basophils, monocytes, macrophages, immature dendritic cells, and T cells, and its capable of inducing crucial immuno-modulatory responses through its effects on epithelial, muscular and endothelial cells. Similar to other CC chemokines, CCL13 binds to several chemokine receptors (CCR1, CCR2 and CCR3), allowing it to elicit different effects on its target cells. A number of studies have shown that CCL13 is involved in many chronic inflammatory diseases, in which it functions as a pivotal molecule involved in the selective recruitment of cell lineages to the inflamed tissues and their subsequent activation. Based on these studies, we suggest that blocking the actions of CCL13 can serve as a novel strategy for the generation of agents with anti-inflammatory activity. The main goal of this review is to present the current information about CCL13, its gene and protein structure and the roles of this chemokine during innate/adaptive immune responses in inflammatory diseases.

TLR4 Signaling augments monocyte chemotaxis by regulating G protein-coupled receptor kinase 2 translocation

Monocytes are critical effector cells of the innate immune system that protect the host by migrating to inflammatory sites, differentiating to macrophages and dendritic cells, eliciting immune responses, and killing pathogenic microbes. MCP-1, also known as CCL2, plays an important role in monocyte activation and migration. The chemotactic function of MCP-1 is mediated by binding to the CCR2 receptor, a member of the G protein-coupled receptor (GPCR) family. Desensitization of GPCR chemokine receptors is an important regulator of the intensity and duration of chemokine stimulation. GPCR kinases (GRKs) induce GPCR phosphorylation, and this leads to GPCR desensitization. Regulation of subcellular localization of GRKs is considered an important early regulatory mechanism of GRK function and subsequent GPCR desensitization. Chemokines and LPS are both present during Gram-negative bacterial infection, and LPS often synergistically exaggerates leukocyte migration in response to chemokines. In this study, we investigated the role and mechanism of LPS-TLR4 signaling on the regulation of monocyte chemotaxis. We demonstrate that LPS augments MCP-1-induced monocyte migration. We also show that LPS, through p38 MAPK signaling, induces phosphorylation of GRK2 at serine 670, which, in turn, suppresses GRK2 translocation to the membrane, thereby preventing GRK2-initiated internalization and desensitization of CCR2 in response to MCP-1. This results in enhanced monocyte migration. These findings reveal a novel function for TLR4 signaling in promoting innate immune cell migration.

Anti-inflammatory cytokines, pro-fibrogenic chemokines and persistence of acute HCV infection

Chemokines and cytokines play a vital role in directing and regulating immune responses to viral infections. Persistent hepatitis C virus (HCV) infection is characterized by the loss of anti-HCV cellular immune responses, while control of HCV infection is associated with maintenance of anti-HCV cellular immune responses. To determine whether plasma concentrations of 19 chemokines and cytokines controlling T-cell trafficking and function differed based on infection outcome, we compared them in at-risk subjects followed prospectively for HCV infection. Levels were compared over time in subjects who controlled HCV infection (Clearance) and subjects who developed persistent HCV infection (Persistence) at two time points during acute infection: (i) first viraemic sample (initial viraemia) and (ii) last viraemic sample in Clearance subjects and time-matched samples in Persistence subjects. At initial viraemia, increased pro-inflammatory tumour necrosis factor α (TNFα) plasma concentrations were observed in the Clearance group, while the plasma levels of anti-inflammatory interleukin (IL)-2, IL-10 and IL-13 were higher in the Persistence group. IL-13 was positively correlated with IL-2 and IL-10 at initial viraemia in the Persistence group. At the time of last viraemia, plasma levels of eotaxin, macrophage chemoattractant protein-4 (MCP-4), IL-5 and IL-10 were higher in the Persistence group and IL-10 and IL-5 levels were positively correlated. Collectively, these results suggest that the development of persistent infection is associated with an anti-inflammatory and pro-fibrogenic chemokine and cytokine profile that is evident at the onset of infection and maintained throughout acute infection.

Structural, genetic, and functional signatures of disordered neuro-immunological development in autism spectrum disorder

Background

Numerous linkage studies have been performed in pedigrees of Autism Spectrum Disorders, and these studies point to diverse loci and etiologies of autism in different pedigrees. The underlying pattern may be identified by an integrative approach, especially since ASD is a complex disorder manifested through many loci.

Method

Autism spectrum disorder (ASD) was studied through two different and independent genome-scale measurement modalities. We analyzed the results of copy number variation in autism and triangulated these with linkage studies.

Results

Consistently across both genome-scale measurements, the same two molecular themes emerged: immune/chemokine pathways and developmental pathways.

Conclusion

Linkage studies in aggregate do indeed share a thematic consistency, one which structural analyses recapitulate with high significance. These results also show for the first time that genomic profiling of pathways using a recombination distance metric can capture pathways that are consistent with those obtained from copy number variations (CNV).

CC motif chemokine ligand 13 is associated with rheumatoid arthritis pathogenesis

OBJECTIVES

CC motif chemokines are considered to be implicated in the pathogenesis of rheumatoid arthritis (RA) via recruitment of monocytes and lymphocytes. CC motif chemokine ligand 13 (CCL13)/monocyte chemoattractant protein-4 (MCP-4) is postulated to be a potent RA inducer. We conducted a study to more precisely clarify the role of CCL13 in RA pathogenesis.

METHODS

CCL13 expression was evaluated by enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining in serum samples and synovial tissues from RA patients. The effects of CCL13 against apoptosis were monitored on cultured synovial fibroblasts. The chemoattractant activity of CCL13 was evaluated by the Boyden chamber assay in monocytes (THP-1 cells) and human umbilical vein endothelial cells (HUVECs).

RESULTS

We found that CCL13 serum level and synovial tissue expression were increased in RA patients. CCL13 had chemoattractant activity for both THP-1 cells and HUVECs. Interestingly, CCL13 expression was positively regulated by tumor necrosis factor-alpha (TNF-α). Furthermore, apoptosis induced by hydrogen peroxide (H2O2) and serum deprivation was inhibited by CCL13 on the cultured synovial fibroblasts.

CONCLUSIONS

CCL13 may be associated with disease progression as a result of its antiapoptotic effects, increased macrophage infiltration, and synovial tissue angiogenesis in RA patients.

Characterization of the rat oncostatin M receptor complex which resembles the human, but differs from the murine cytokine receptor

Evaluation of a pathophysiological role of the interleukin-6-type cytokine oncostatin M (OSM) for human diseases has been complicated by the fact that mouse models of diseases targeting either OSM or the OSM receptor (OSMR) complex cannot fully reflect the human situation. This is due to earlier findings that human OSM utilizes two receptor complexes, glycoprotein 130 (gp130)/leukemia inhibitory factor receptor (LIFR) (type I) and gp130/OSMR (type II), both with wide expression profiles. Murine OSM on the other hand only binds to the gp130/OSMR (type II) receptor complex with high affinity. Here, we characterize the receptor usage for rat OSM. Using different experimental approaches (knock-down of the OSMR expression by RNA interference, blocking of the LIFR by LIF-05, an antagonistic LIF variant and stably transfected Ba/F3 cells) we can clearly show that rat OSM surprisingly utilizes both, the type I and type II receptor complex, therefore mimicking the human situation. Furthermore, it displays cross-species activities and stimulates cells of human as well as murine origin. Its signaling capacities closely mimic those of human OSM in cell types of different origin in the way that strong activation of the Jak/STAT, the MAP kinase as well as the PI3K/Akt pathways can be observed. Therefore, rat disease models would allow evaluation of the relevance of OSM for human biology.

Estrogen inhibits apoptosis and promotes CC motif chemokine ligand 13 expression on synovial fibroblasts in rheumatoid arthritis

OBJECTIVE

Female patients have a higher prevalence of rheumatoid arthritis (RA) than male patients, suggesting that female sex hormones contribute to the disease pathogenesis. We herein report the findings of our study, which was conducted to clarify the role of estrogen in the pathogenesis of RA.

METHODS

Cultured human synovial fibroblasts from a patient with RA were treated with 17β-estradiol (E(2)). The effects of E(2) against cellular activation and apoptosis were evaluated. To identify the disease-related genes altered by E(2) treatment, the changes in the gene expression of the cells stimulated with and without E(2) were evaluated using a microarray analysis.

RESULTS

We found that E(2)-mediated cellular activation signaling through extracellular signal-regulated kinase (ERK)-1/2. E(2) possessed a suppressive effect for apoptosis and a promotive effect for tumor necrosis factor (TNF)-α-induced matrix metalloproteinase (MMP)-3 production on the synovial fibroblasts. A microarray analysis revealed that E(2) profoundly upregulated CC motif chemokine ligand 13 (CCL13) gene expression.

CONCLUSIONS

E(2) could mediate cellular activation signaling through ERK-1/2 on the synovial fibroblasts. The present data suggest that E(2) has adverse effects on the pathogenesis of RA as a result of unregulated cell death, increased TNF-α-induced MMP-3 production, and CCL13 overproduction, subsequently resulting in the disease progression of RA.

Influence of Janus kinase inhibition on interleukin 6-mediated induction of acute-phase serum amyloid A in rheumatoid synovium

OBJECTIVE

Inhibition of intracellular signal transduction is considered to be a therapeutic target for chronic inflammation. The new Janus kinase (JAK)3 inhibitor CP690,550 has shown efficacy in the treatment of rheumatoid arthritis (RA). We investigated the influence of JAK/STAT inhibition using CP690,550 on the induction of acute-phase serum amyloid A (SAA), which is triggered by interleukin 6 (IL-6) stimulation in rheumatoid fibroblast-like synoviocytes (RA-FLS).

METHODS

IL-6-stimulated gene expression of the acute-phase serum amyloid A genes (A-SAA; encoded by SAA1+SAA2) and SAA4 was analyzed by reverse transcriptase-polymerase chain reaction. The intracellular signaling pathway mediating the effects of CP690,550 on IL-6-stimulated JAK/STAT activation was assessed by measuring the phosphorylation levels using Western blots.

RESULTS

IL-6 trans-signaling induced A-SAA messenger RNA (mRNA) expression in RA-FLS. By contrast IL-6 stimulation did not affect SAA4 mRNA expression, which is expressed constitutively in RA-FLS. IL-6 stimulation elicited rapid phosphorylation of JAK2 and STAT3, which was blunted by CP690,550. CP690,550 abrogated IL-6-mediated A-SAA mRNA expression in RA-FLS. Similarly, CP690,550 inhibited IL-6-mediated A-SAA mRNA expression in human hepatocytes.

CONCLUSION

Our data indicated that CP690,550 blocked IL-6-induced JAK2/STAT3 activation, as well as the induction of A-SAA. Inhibition of IL-6-mediated proinflammatory signaling pathways by CP690,550 may represent a new antiinflammatory therapeutic strategy for RA and AA amyloidosis.

A receptor fusion protein for the inhibition of murine oncostatin M

Background

Most cytokines signal through heteromeric receptor complexes consisting of two or more different receptor subunits. Fusion proteins of the extracellular parts of receptor subunits turned out to be promising cytokine inhibitors useful in anti-cytokine therapy and cytokine research.

Results

We constructed receptor fusion proteins (RFP) consisting of the ligand binding domains of the murine oncostatin M (mOSM) receptor subunits mOSMR and mgp130 connected by a flexible linker as potential mOSM inhibitors. mgp130 is a shared cytokine receptor that is also used by other cytokines such as IL-6 and leukemia inhibitory factor (LIF). In this study we compare four types of mOSM-RFPs that contain either domains D1-D3 or domains D2-D3 of mgp130 and are arranged in two ways. Domain D1 of mgp130 turned out to be dispensable for mOSM-binding. However, the arrangement of the two receptor subunits is essential for the inhibitory activity. We found mOSM induced STAT3 phosphorylation to be suppressed only when the mOSMR fragment was fused in front of the mgp130 fragment.

Conclusions

mOSM-RFP consisting of D1-D4 of mOSMR and D2-D3 of mgp130 is a highly potent and specific inhibitor of mOSM. Since mOSM-RFP is encoded by a single gene it offers numerous possibilities for specific cytokine inhibition in gene delivery approaches based on viral vectors, transgenic animals and finally gene therapy.

Transcriptional Profiling of Liver and Effect of Glucocorticoids in a Rat Adjuvant-Induced Arthritis Model

Glucocorticoids (GCs), despite having many undesirable side effects, remain effective for the treatment of many inflammatory diseases and are commonly used as benchmark drugs in animal models of disease. However, the molecular mechanisms underling systemic GC effects in these models are poorly characterized. In this study, prednisolone and dexamethasone were evaluated in the fully established Lewis rat adjuvant-induced arthritis (AIA) model. In AIA, adjuvant administration induced polyarticular and systemic inflammation, which included spleen and liver. In the liver, multifocal hepatic granulomas were observed. To characterize the systemic response and the pathways responsible for GC effects, histology, transcriptional profiling, and immunohistochemistry (IHC) were performed. There was a decrease in the incidence and histologic severity score for granulomas with GC treatment. There was no effect on cellular composition of granulomas as assessed by IHC for CD3+ lymphocytes, macrophages, and B cells, but there was a significant reduction in infiltrating lymphocytes in the hepatic parenchyma. By Affymetrix microarray analysis, 10% of hepatic transcripts were altered ( P < .01) in livers from AIA rats, with ~31% of them partially reversed with treatment with dexamethasone and ~13% with prednisolone. Many of these altered hepatic transcripts correspond to human genes that are dysregulated in the synovium in human rheumatoid arthritis (RA), indicating that the rat AIA model shares features with human RA. These data establish molecular changes in the liver and the effect of GCs in rat AIA, which can be used to aid in understanding the mechanism of action of novel anti-inflammatory compounds in this animal model.

Rheumatoid arthritis progression mediated by activated synovial fibroblasts

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia and progressive joint destruction. Rheumatoid arthritis synovial fibroblasts (RASFs) are leading cells in joint erosion and contribute actively to inflammation. RASFs show an activated phenotype that is independent of the inflammatory environment and requires the combination of several factors. Although new aspects regarding RASF activation via matrix degradation products, epigenetic modifications, inflammatory factors, Toll-like receptor (TLR) activation and others have recently been uncovered, the primary pathophysiological processes in early arthritis leading to permanent activation are mostly unknown. Here, we review new findings regarding RASF activation and their altered behavior that contribute to matrix destruction and inflammation as well as their potential to spread RA.

gp130 at the nexus of inflammation, autoimmunity, and cancer

Glycoprotein 130 (gp130) is a shared receptor utilized by several related cytokines, including IL-6, IL-11, IL-27, Leukemia Inhibitory Factor (LIF), Oncostatin M (OSM), Ciliary Neurotrophic Factor (CNTF), Cardiotrophin 1 (CT-1) and Cardiotrophin-like Cytokine (CLC). Gp130 plays critical roles during development and gp130-deficient mice are embryonically lethal. However, the best characterized facet of this receptor and its associated cytokines is the ability to promote or suppress inflammation. The aim of this review is to discuss the role of gp130 in promoting or preventing the development of autoimmunity and cancer, two processes that are associated with aberrant inflammatory responses.

Suppression of Autoimmune Arthritis by Small Molecule Inhibitors of the JAK/STAT Pathway

A skewed ratio of pro-inflammatory to anti-inflammatory cytokines, elevated growth factor synthesis and T- and B-lymphocyte activation are 3 hallmarks of rheumatoid arthritis (RA) pathology. Interleukin-6 (IL-6), IL-7, IL-17, IL-12/IL-23 and growth factors, granulocyte macrophage-colony stimulating factor, IL-3, and erythropoietin activate the Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) pathway. Evidence showed that STAT protein phosphorylation (p-STAT) by activated JAKs is permissive for p-STAT to act as transcription factors by binding to STAT-responsive gene promoter sequences. This event is critical for perpetuating RA, in part, by up-regulating pro-inflammatory cytokine gene transcription. Activation of JAK/STAT by cytokines and growth factors can induce ‘cross-talk’ with other signaling pathways by which Stress-Activated Protein/Mitogen-Activated Protein Kinase (SAP/MAPK) and Phosphatidylinositide-3-Kinase (PI3K)-mediated signaling are also activated. JAK-specific small molecule inhibitors (SMIs) were developed to test whether JAK/STAT pathway blockade would regulate autoimmune-mediated inflammation. JAK-specific SMI blockade inhibited p-STAT induced by pro-inflammatory cytokines in vitro. Systemically administered JAK-specific SMI blockade also ameliorated biomarkers of inflammation in well-validated arthritis animal models. A few JAK-specific SMIs have made their way into RA clinical trials. In fact, the JAK3-specific SMI, CP-690,500 is the first JAK/STAT SMI to be assessed for clinical efficacy in a Phase III RA trial.