Expression of chemokines and matrix metalloproteinases in early rheumatoid arthritis

Migration and homeostasis of regulatory T cells in rheumatoid arthritis

Regulatory T (T_reg) cells are garnering increased attention in research related to autoimmune diseases, including rheumatoid arthritis (RA). They play an essential role in the maintenance of immune homeostasis by restricting effector T cell activity. Reduced functions and frequencies of T_reg cells contribute to the pathogenesis of RA, a common autoimmune disease which leads to systemic inflammation and erosive joint destruction. T_reg cells from patients with RA are characterized by impaired functions and by an altered phenotype. They show increased plasticity towards Th17 cells and a reduced suppressive capacity. Besides the suppressive function of T_reg cells, their effectiveness is determined by their ability to migrate into inflamed tissues. In the past years, new mechanisms involved in T_reg cell migration have been identified. One example of such a mechanism is the phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Efficient migration of T_reg cells requires the presence of VASP. IL-6, a cytokine which is abundantly present in the peripheral blood and in the synovial tissue of RA patients, induces posttranslational modifications of VASP. Recently, it has been shown in mice with collagen-induced arthritis (CIA) that this IL-6 mediated posttranslational modification leads to reduced T_reg cell trafficking. Another protein which facilitates T_reg cell migration is G-protein-signaling modulator 2 (GPSM2). It modulates G-protein coupled receptor functioning, thereby altering the cellular activity initiated by cell surface receptors in response to extracellular signals. The almost complete lack of GPSM2 in T_reg cells from RA patients contributes to their reduced ability to migrate towards inflammatory sites. In this review article, we highlight the newly identified mechanisms of T_reg cell migration and review the current knowledge about impaired T_reg cell homeostasis in RA.

Utility of Baseline Transcriptomic Analysis of Rheumatoid Arthritis Synovium as an Indicator for Long-Term Clinical Outcomes

Objective:

Rheumatoid arthritis is a chronic inflammatory autoimmune disease that can lead to synovial damage, persistent joint pain, and functional disability. Our objective was to evaluate baseline synovial transcriptome from early inflammatory arthritis patients (EIA) and identify pretreatment biomarkers that could potentially provide insights into long-term functional outcomes of rheumatoid arthritis (RA).

Methods

Synovial biopsies from clinically inflamed knee joints were procured from either 17 EIA patients before initiation of disease modifying anti-rheumatic drug (DMARD) therapy (DMARD-naïve EIA) using the minimally invasive closed needle biopsy technique or advanced RA patients undergoing arthroplasty. Affymetrix Human Genome U133 Plus 2 microarray platform was used to profile the synovial transcriptome. The cohort was followed clinically for a median of 12.3 years, and patient data was collected at each visit. Short-term and long-term clinical outcomes were determined by assessing RA-associated clinical parameters Statistical adjustments were made to account for asynchronous clinical visits and duration of follow up.

Results

Based on the transcriptomic analysis, we identified 5 differentially expressed genes (DEGs), including matrix metalloproteinase (MMP)-1 (fibroblast collagenase) and MMP-3 (stromelysin-1) in DMARD-naïve EIA patients, relative to advanced RA patients (q < 0.05). Dichotomous expression of MMP-1 and MMP-3 mRNA and protein was confirmed by qPCR and immunohistochemistry respectively, based on which DMARD-naïve EIA subjects were classified as MMP-high or MMP-low. Hierarchical clustering of transcriptomic data identified 947 DEGs between MMP-high and MMP-low cohorts. Co-expression and IPA analysis of DEGs in the MMP-high cohort showed an enrichment of genes that participated in metabolic or biochemical functions and intracellular immune signaling were regulated through NF-κB and β-catenin complexes and correlated with markers of systemic inflammation. Analysis of short-term clinical outcomes in MMP-high cohort showed a significant reduction in the DAS-CRP scores relative to baseline (P <0.001), whereas area under the curve analyses of modified HAQ (mHAQ) scores correlated negatively with baseline MMP-1 (R = −0.59, P = 0.03). Further, longitudinal mHAQ scores, number of swollen joints, number of DMARDs and median follow-up duration appeared to be higher in MMP-low cohort.

Conclusion

Overall, our results indicate that the gene expression profiling of synovial biopsies obtained at the DMARD-naive stage in patients with EIA categorizes them into subsets with varying degrees of inflammation and can predict the future of long-term clinical outcome.

Impact of synovial biopsy procedures and disease-specific aspects on synovial tissue outcome: a systematic literature review informing the EULAR points to consider for the minimal reporting requirements in synovial tissue research in rheumatology

BACKGROUND

The aim of this work was to summarise the literature evaluating the impact of biopsy procedures, tissue handling, tissue quality and disease-specific aspects including joint biopsied and disease stage, on synovial tissue outcome.

METHODS

Two reviewers independently identified eligible studies according to the Patients, Intervention, Comparator and Outcome framework obtained for five research questions formulated during the first EULAR task force meeting to produce points to consider (PtC) for minimal reporting requirements in synovial tissue studies. The databases explored were Medline, Embase, CENTRAL and Cinhal. The risk of bias of each study was evaluated using an adapted version of the Joanna Briggs Institute checklist for analytical cross-sectional studies.

RESULTS

Of the 7654 records yielded, 75 full texts were assessed, leading to the inclusion of 26 manuscripts in the systematic literature review (SLR). Two papers assessed the impact of biopsy procedures on the quality and quantity of tissue retrieved alongside patient tolerability; six papers focused on synovial tissue variability. Four papers studied the impact of sample handling or randomisation and 14 assessed the impact of disease stage and state, namely early or established active rheumatoid arthritis and remission on histopathological and transcriptomic results.

CONCLUSIONS

This SLR informs the EULAR PtC for minimal reporting requirements in synovial tissue research in rheumatology. Characteristics related to the study design, population, sample handling, randomisation and analysis can affect the final synovial tissue outcome in the studies reviewed. Thus, accurate reporting of these factors is required in order to ensure the scientific validity of manuscripts describing synovial tissue outcomes.

Intermediate monocytes correlate with CXCR3+ Th17 cells but not with bone characteristics in untreated early rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is associated with development of generalized osteoporosis. Bone-degrading osteoclasts are derived from circulating precursor cells of monocytic lineage, and the intermediate monocyte population is important as osteoclast precursors in inflammatory conditions. T cells of various subsets are critical in the pathogenesis of both RA and associated osteoporosis, but so far, no studies have examined associations between circulating intermediate monocytes, T cell subsets and bone characteristics in patients with RA. The aim of this study was to investigate the frequency of intermediate monocytes in patients with untreated early rheumatoid arthritis (ueRA) compared to healthy controls (HC), and to explore the correlation between intermediate monocytes and a comprehensive panel of T helper cell subsets, bone density and bone microarchitecture in ueRA patients.

METHODS

78 patients with ueRA fulfilling the ACR/EULAR 2010 criteria were included and compared to 29 age- and sex-matched HC. Peripheral blood samples were obtained before start of treatment and proportions of monocyte subsets and CD4+ helper and regulatory T cell subsets were analyzed by flow cytometry. Bone densitometry was performed on 46 of the ueRA patients at inclusion using DXA and HR-pQCT.

RESULTS

Flow cytometric analyses showed that the majority of ueRA patients had frequencies of intermediate monocytes comparable to HC. The intermediate monocyte population correlated positively with CXCR3+ Th17 cells in ueRA patients but not in HC. However, neither the proportions of intermediate monocytes nor CXCR3+ Th17 cells were associated with bone density or bone microarchitecture measurements.

CONCLUSIONS

Our findings suggest that in early RA, the intermediate monocytes do not correlate with bone characteristics, despite positive correlation with circulating CXCR3+ Th17 cells. Future longitudinal studies in patients with longer disease duration are required to fully explore the potential of intermediate monocytes to drive bone loss in RA.

The effects of nanomicelle of curcumin on the matrix metalloproteinase (MMP-2, 9) activity and expression in patients with coronary artery disease (CAD): A randomized controlled clinical trial

BACKGROUND

Coronary artery disease (CAD) is the most common type of cardiovascular disease. Increasing the expression and activity of matrix metalloproteinases (MMPs) facilitates vascular remodeling and cardiovascular complications. Curcumin (the active ingredient of turmeric) is a potent natural anti-inflammatory agent, with cardiovascular protective effects. The present study was a clinical trial for investigating the effects of curcumin on activity and gene expression of MMP-2 and MMP-9 in patients with CAD.

METHODS

In this study, 70 patients with CAD (with 40%-50% stenosis) were randomly divided into two groups of curcumin (80 mg nanomicelle per day) and placebo. The intervention lasted 3 months. The activity levels of MMP-2 and MMP-9 in serum samples of patients were measured using gelatin zymography assay before and after the intervention. MMP-2 and MMP-9 gene expression in peripheral blood mononuclear cells (PBMCs) was also analyzed using real-time polymerase chain reaction (PCR). Statistical significance was set at P < 0.0500.

RESULTS

After 3 months of medication, the expression of MMP-9 produced by PBMCs significantly decreased in the curcumin group (0.811 ± 0.25) in comparison with the placebo group (2.23 ± 0.94) (P < 0.0001). Furthermore, the zymographic analysis showed that the administration of curcumin significantly inhibited the activity levels of MMP-2 (12469.7 ± 5308.64 pixels) and MMP-9 (14007.2 ± 5371.67 pixels) in comparison with that in patients receiving placebo (MMP-2: 17613.8 ± 5250.68 pixels; MMP-9: 20010.1 ± 3259.37 pixels) (P < 0.0500).

CONCLUSION

Our results show that curcumin can significantly reduce the expression and activity of MMP-2 and MMP-9. Because of the anti-inflammatory effects of curcumin, this compound can be considered as a new strategy for the prevention of cardiovascular events.

Increased monocyte chemoattractant protein-1 and nitrotyrosine are associated with increased body weight in patients with rheumatoid arthritis after etanercept therapy

OBJECTIVES

Etanercept, a tumor necrosis factor inhibitor, is an effective drug for patients with active rheumatoid arthritis (RA). Monocyte chemoattractant protein-1 (MCP-1) and nitrotyrosine (NT) are pro-inflammatory biomolecules associated with satiety and increased body weight. We evaluated whether MCP-1 and NT are associated with decreased inflammation or increased body mass during etanercept therapy in active RA patients.

METHODS

RA patients with moderate to high disease activity were enrolled to receive add-on etanercept (25 mg subcutaneous injection, biweekly) for at least one year, combined with sustained treatment with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs).

RESULTS

Forty patients received add-on etanercept and 15 received DMARDs alone. At the end of one year, etanercept significantly reduced the disease activity score of 28 joints, C-reactive protein, and erythrocyte sedimentation rate. Moreover, etanercept significantly increased the body weight, body mass index (BMI), as well as MCP-1 and NT levels, compared to that in the csDMARD-only group.

CONCLUSIONS

Increased serum MCP-1 and NT levels in RA patients with moderate to high disease activity, who underwent one-year etanercept treatment, might be attributed to increase in body weight and BMI rather than induction of more severe autoimmune inflammation.

Differentially Expressed Genes of Natural Killer Cells Can Distinguish Rheumatoid Arthritis Patients from Healthy Controls

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases, while its molecular triggers are not fully understood. A few studies have shown that natural killer (NK) cells may play either a pathogenic or a protective role in RA. In this study, we sought to explore NK cell markers that could be plausibly used in evaluating the differences among healthy controls and RA patients. Publicly available transcriptome datasets from RA patients and healthy volunteers were analyzed, in order to identify differentially expressed genes (DEGs) between 1. different immune cells as compared to NK cells, and 2. NK cells of RA patients and healthy controls. The identified DEGs were validated using 16 healthy controls and 17 RA patients. Peripheral blood mononuclear cells (PBMCs) were separated by Ficoll density gradient method, while NK cells were isolated using RosetteSep technique. RNA was extracted and gene expression was assessed using RT-qPCR. All selected genes were differentially expressed in NK cells compared to PBMCs. CD56, CXCL16, PECAM-1, ITGB7, BTK, TLR10, and IL-1β were significantly upregulated, while CCL2, CCR4, RELA and IBTK were downregulated in the NK cells of RA patients when compared to healthy controls. Therefore, these NK specific genes might be used as promising biomarkers for RA diagnosis.

Role of Chemokines and Chemokine Receptors in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases and a prototypic inflammatory disease, affecting the small joints of the hands and feet. Chemokines and chemokine receptors play a critical role in RA pathogenesis via immune cells recruitment. Several chemokines and chemokine receptors are abundant in the peripheral blood and in the local inflamed joints of RA. Furthermore, synthetic and biologics disease modifying anti rheumatic drugs have been reported to affect chemokines expression. Thus, many studies have focused on targeting chemokines and chemokine receptors, where some have shown positive promising results. However, most of the chemokine blockers in human trials of RA treatment displayed some failures that can be attributed to several reasons in their structures and binding affinities. Nevertheless, targeting chemokines will continue to be under development, in order to improve their therapeutic potentials in RA and other autoimmune diseases. In this review we provide an up-to-date knowledge regarding the role of chemokines and chemokine receptors in RA with an emphasis on their activities on immune cells. We also discussed the effects of drugs targeting those molecules in RA. This knowledge might provide impetus for developing new therapeutic modalities to treat this chronic disease.

Silencing MicroRNA-155 Attenuates Cardiac Injury and Dysfunction in Viral Myocarditis via Promotion of M2 Phenotype Polarization of Macrophages

Macrophage infiltration is a hallmark feature of viral myocarditis. As studies have shown that microRNA-155 regulates the differentiation of macrophages, we aimed to investigate the role of microRNA-155 in VM. We report that silencing microRNA-155 protects mice from coxsackievirus B3 induced myocarditis. We found that microRNA-155 expression was upregulated and localized primarily in heart-infiltrating macrophages and CD4⁺ T lymphocytes during acute myocarditis. In contrast with wildtype (WT) mice, microRNA-155^−/− mice developed attenuated viral myocarditis, which was characterized by decreased cardiac inflammation and decreased intracardiac CD45⁺ leukocytes. Hearts of microRNA-155^−/− mice expressed decreased levels of the IFN-γ and increased levels of the cytokines IL-4 and IL-13. Although total CD4⁺ and regulatory T cells were unchanged in miR-155^−/− spleen proportionally, the activation of T cells and CD4⁺ T cell proliferation in miR-155^−/− mice were significantly decreased. Beyond the acute phase, microRNA-15^5−/− mice had reduced mortality and improved cardiac function during 5 weeks of follow-up. Moreover, silencing microRNA-155 led to increased levels of alternatively-activated macrophages (M2) and decreased levels of classically-activated macrophages (M1) in the heart. Combined, our studies suggest that microRNA-155 confers susceptibility to viral myocarditis by affecting macrophage polarization, and thus may be a potential therapeutic target for viral myocarditis.

Inflammatory cytokine response following acute tibial plateau fracture

BACKGROUND

The objective of the present study was to evaluate human synovial fluid for inflammatory cytokine concentrations following acute tibial plateau fracture. Our hypothesis was that there would be an elevated inflammatory response following intra-articular fracture, and that the inflammatory response would be greater after high-energy compared with low-energy injuries.

METHODS

Between December 2011 and June 2013, we prospectively enrolled forty-five patients with an acute tibial plateau fracture. Synovial fluid aspirations were performed on the injured and uninjured knees. Twenty patients who required an external fixator followed by delayed fixation underwent aspiration at both surgical procedures. The concentrations of interferon-gamma (IFN-γ), interleukin-1 beta (IL-1β), interleukin-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12(p70), IL-13, IL-17A, tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β) were quantified with use of multiplex assays.

RESULTS

The forty-five patients had an average age of forty-two years (range, twenty to sixty years). There were twenty-four low-energy and twenty-one high-energy tibial plateau injuries. There was a significant difference between injured and uninjured knees (p < 0.001) with regard to concentrations of IL-1β, IL-6, IL-8, IL-10, IL-1RA, and MCP-1. There was not a detectable difference in synovial fluid cytokine concentrations between high and low-energy injuries. The concentrations of IL-10 (p < 0.001), IL-1RA (p = 0.002), IL-6 (p < 0.001), IL-8 (p < 0.001), and MCP-1 (p = 0.002) were significantly greater in the injured knee than in the uninjured knee at the second aspiration, at a mean of 9.5 days (range, three to twenty-one days) after the initial injury.

CONCLUSIONS

There was a significant local inflammatory response following acute tibial plateau fracture. There was not a detectable difference in inflammatory cytokine concentration between high and low-energy injuries. Synovial fluid concentrations of IL-10, IL-8, IL-6, IL-1RA, and MCP-1 remained elevated at the second aspiration.

Recombinant human interleukin receptor antagonist influences serum chemokines in patients with rheumatoid arthritis

OBJECTIVE

To investigate the serum expressions of chemokines CCL2 and CCL3 in patients with rheumatoid arthritis (RA) who were treated with recombinant human interleukin 1 (IL-1) receptor antagonist (IL-1Ra).

MATERIAL AND METHODS

Serum CCL2 and CCL3 were determined using an enzyme-linked immunosorbent assay in 54 active RA patients before and after treatment with IL-1Ra or a placebo, as well as 36 healthy controls.

RESULTS

Compared with the healthy controls, all the 54 RA patients exhibited higher serum CCL2 and CCL3 before and after treatment (p < 0.05). However, patients who had a good response to IL-1Ra treatment had significantly lower mean changes in the serum CCL2 and CCL3 levels from baseline to the last injection than IL-1Ra non-responders (p < 0.01).

CONCLUSIONS

CCL2 and CCL3 may be useful efficacy markers of IL-1Ra treatment.

Genetic and cellular evidence of decreased inflammation associated with reduced incidence of posttraumatic arthritis in MRL/MpJ mice

OBJECTIVE

To examine the relationship between inflammation and posttraumatic arthritis (PTA) in a murine intraarticular fracture model.

METHODS

Male C57BL/6 and MRL/MpJ "superhealer" mice received tibial plateau fractures using a previously established method. Mice were killed on day 0 (within 4 hours of fracture) and days 1, 3, 5, 7, 28, and 56 after fracture. Synovial tissue samples, obtained prior to fracture and on days 0, 1, 3, 5, and 7 after fracture, were examined by reverse transcription-polymerase chain reaction for gene expression of proinflammatory cytokines and chemokines. Synovial fluid and serum samples were collected to measure cytokine concentrations, using enzyme-linked immunosorbent assay. Whole joints were examined histologically for the extent of synovitis and cartilage degradation, and joint tissue samples from all time points were analyzed immunohistochemically to evaluate the distribution of interleukin-1 (IL-1).

RESULTS

Compared to C57BL/6 mice, MRL/MpJ mice had less severe intraarticular and systemic inflammation following joint injury, as evidenced by lower gene expression of tumor necrosis factor α and IL-1β in the synovial tissue and lower protein levels of IL-1α and IL-1β in the synovial fluid, serum, and joint tissues. Furthermore, after joint injury, MRL/MpJ mice had lower gene expression of macrophage inflammatory proteins and macrophage-derived chemokine (CCL22) in the synovial tissue, and also had reduced acute and late-stage infiltration of synovial macrophages.

CONCLUSION

C57BL/6 mice exhibited higher levels of inflammation than MRL/MpJ mice, indicating that MRL/MpJ mice are protected from PTA in this model. These data thus suggest an association between joint tissue inflammation and the development and progression of PTA in mice.

Anti-inflammatory and anti-oxidant properties of Curcuma longa (turmeric) versus Zingiber officinale (ginger) rhizomes in rat adjuvant-induced arthritis

Turmeric (rich in curcuminoids) and ginger (rich in gingerols and shogaols) rhizomes have been widely used as dietary spices and to treat different diseases in Ayurveda/Chinese medicine since antiquity. Here, we compared the anti-inflammatory/anti-oxidant activity of these two plants in rat adjuvant-induced arthritis (AIA). Both plants (at dose 200 mg/kg body weight) significantly suppressed (but with different degrees) the incidence and severity of arthritis by increasing/decreasing the production of anti-inflammatory/pro-inflammatory cytokines, respectively, and activating the anti-oxidant defence system. The anti-arthritic activity of turmeric exceeded that of ginger and indomethacin (a non-steroidal anti-inflammatory drug), especially when the treatment started from the day of arthritis induction. The percentage of disease recovery was 4.6-8.3% and 10.2% more in turmeric compared with ginger and indomethacin (P < 0.05), respectively. The present study proves the anti-inflammatory/anti-oxidant activity of turmeric over ginger and indomethacin, which may have beneficial effects against rheumatoid arthritis onset/progression as shown in AIA rat model.

MMP-Activated Fluorescence Imaging Detects Early Joint Inflammation in Collagen-Antibody-Induced Arthritis in CC-Chemokine Receptor-2-Null Mice, In-Vivo

The Standard measures of experimental arthritis fail to detect, visualize, and quantify early inflammation and disease activity. Here, we describe the use of an injectable MMP-activated fluorescence agent for in vivo quantification of acute inflammation produced by collagen-antibody-induced arthritis (CAIA) in CC chemokine receptor-2 (Ccr2^−/−) null mice. Although Ccr2^−/− DBA1/J mice were highly susceptible to and rapidly developed CAIA, the standard clinical assessment of fore or hind paw thicknesses was unable to detect significant acute inflammatory changes (days 3–10). Remarkably, noninvasive, in situ, MMP-activatable fluorescent imaging of Ccr2^−/− DBA1/J mice with CAIA displayed acute joint pathology in advance of clinically measurable acute inflammation (days 5, 7, and 10). These results were confirmed by the histology of ankle joints, which showed significant inflammation, bone loss, and synovial hyperplasia, compared to control mice at postimmunization day 5. The MMP-mediated fluorescence technique holds tremendous implications for quantifiable examination of arthritis disease activity of acute joint inflammation.

T helper cells promote disease progression of osteoarthritis by inducing macrophage inflammatory protein-1γ

OBJECTIVE

Immune cells are involved in the pathogenesis of osteoarthritis (OA). We examined the effects of T helper (Th) cells, which induce the expression of macrophage inflammatory protein (MIP-1γ), on the progression of OA.

DESIGN

Using anterior cruciate ligament-transection (ACLT), we induced OA in one hind-leg knee joint of B6 mice. The CD4(+) T cells from splenocytes and synovium were flow-cytometrically and immunochemically evaluated, respectively. The knee joints were histologically assessed for manifestations of OA. MIP-1γ levels and nuclear factor-κB (NF-κB) in the knee joints were measured using enzyme-linked immunosorbent and immunoblotting assays, respectively; osteoclastogenesis was detected by tartrate-resistant acid phosphatase (TRAP) staining. The inflammatory responses and MIP-1γ expression were examined using immunohistochemistry.

RESULTS

The number of CD4(+) T cells and the expression of interferon-γ (IFN-γ) increased during OA onset (30 days after ACLT) and then decreased at a later stage of OA (90 days after ACLT). Tissue damage induced by CD4(+) T cells was evident at the later stage. The activation of CD4(+) T cells induced the expression of MIP-1γ and NF-κB. The expression of MIP-1γ can be detected in synovium which CD4(+) T cells were infiltrated. The increased MIP-1γ expression caused an increase in the number of osteoclasts in joints. The regulation of CD4(+) T cells was accompanied by increased macrophage infiltration and matrix metalloproteinase (MMP)-9 expression. Histopathological examinations revealed that CD4(+) T cell knockout (CD4(-/-)) mice had less expression of MIP-1γ and slower cartilage degeneration than control mice had.

CONCLUSIONS

CD4(+) T cells were activated during the onset of OA, but cartilage damage was more prominent at a later stage. CD4(+) T cells were involved in the pathogenesis of OA: they induced MIP-1γ expression and subsequent osteoclast formation.

Galectin-9 administration ameliorates CVB3 induced myocarditis by promoting the proliferation of regulatory T cells and alternatively activated Th2 cells

In this study we explored the effects of galectin-9 on CVB3 induced myocarditis and its possible mechanisms involved. We demonstrated that galectin-9 expression was significantly up-regulated in the myocardium following CVB3 infection and was correlated with the severity of viral myocarditis. To explore whether galectin-9 may have therapeutic effect on the CVB3 induced myocarditis, galectin-9 was administered daily to mice following CVB3 infection. Significantly reduced CD4(+) T cells and remarkably increased regulatory T cells frequency in the heart tissue were found as compared to the non-treated mice. It was accompanied by a significant decreased level of Th1 cytokines as TNF-α and IFN-γ both in the myocardium and serum, and an increased level of Th2 cytokines such as IL-4 and IL-10. Galectin-9 was further found to promote the proliferation of regulatory T cells and elevated IL-4-secreting Th2 cells. It may represent as a novel therapeutic strategy in treating Th1-mediated inflammatory cardiac disease.

Pharmacokinetic-pharmacodynamic modeling of apratastat: a population-based approach

Apratastat is an orally active, potent, and reversible dual inhibitor of tumor necrosis factor-α converting enzyme (TACE) and matrix metalloproteinases (MMPs). This study characterizes the pharmacodynamic (PD) effect of apratastat following oral administration on tumor necrosis factor-alpha (TNF-α) release. Data were obtained from 3 clinical studies carried out in healthy subjects. Apratastat was administered orally in these studies as single doses or multiple doses (twice daily). The inhibition of TNF-α release by apratastat was investigated in studies of in vitro, ex vivo, and in vivo. Inhibitory E(max) models were used to characterize the inhibition of TNF-α release in both in vitro and ex vivo studies. Apratastat inhibited TNF-α release with a population mean IC(50) of 144 ng/mL in vitro and of 81.7 ng/mL ex vivo, respectively. The relationship between TNF-α and apratastat plasma concentration in the endotoxin-challenged study in healthy subjects was well characterized by a mechanism-based PD population model with IC(50) of 126 ng/mL. Apratastat can potently inhibit the release of TNF-α in vitro, ex vivo, and in vivo. Even though the dosage provided adequate exposure to inhibit TNF-α release, apratastat was not efficacious in rheumatoid arthritis (RA). This inconsistency between TNF-α inhibition and the clinical response requires further investigation.

Serum chemokines in patients with rheumatoid arthritis treated with etanercept

Chemokines promote leucocyte traffic into the synovium, leading to the initiation and progression of the rheumatoid arthritis (RA). The aim of the study was to determine the effects of etanercept, a soluble tumour necrosis factor receptor (sTNFr), on the serum chemokines levels in patients with active RA. Patients were treated with 50 mg of subcutaneous injection of etanercept per week and methotrexate (10-25 mg/week). Serum levels of interleukin-8 (IL-8), RANTES (regulated upon activation, normal T cell expressed and secreted) and monocyte chemoattractant protein-1 (MCP-1) were assessed by ELISA at months 0, 3, 6, 9 and 12, prior to injection. 3-month treatment with etanercept diminished serum concentrations of IL-8, RANTES and MCP-1 (P < 0.05, P < 0.01 and P < 0.001, respectively). Subsequent etanercept administrations prolonged decrease in serum chemokines levels and in the case of IL-8 even intensified the reduction of its concentration in serum. These changes were accompanied by significant decrease of disease activity score (DAS28) (in all cases P < 0.001). Prior to the first etanercept administration, serum concentrations of studied chemokines correlated with markers of RA activity such as the erythrocyte sedimentation rate (ESR) and DAS28. Following next drug injection such associations were less or not significant. Therapy with etanercept and MTX not only caused a clinical improvement but also diminished serum chemokines levels in RA patients. Further treatment with etanercept sustained chemokines suppression.

Essential role for TRPV1 in stress-induced (mast cell-dependent) colonic hypersensitivity in maternally separated rats

Irritable bowel syndrome is in part characterized by an increased sensitivity to colonic distension. Stress is an important trigger factor for symptom generation. We hypothesized that stress induces visceral hypersensitivity via mast cell degranulation and transient receptor ion channel 1 (TRPV1) modulation. We used the rat model of neonatal maternal separation (MS) to investigate this hypothesis. The visceromotor response to colonic distention was assessed in adult MS and non-handled (NH) rats before and after acute water avoidance (WA) stress. We evaluated the effect of the mast cell stabilizer doxantrazole, neutralizing antiserum against the mast cell mediator nerve growth factor (NGF) and two different TRPV1 antagonists; capsazepine (non-specific) and SB-705498 (TRPV1-specific). Immunohistochemistry was used to assess post-WA TRPV1 expression in dorsal root ganglia and the presence of immunocytes in proximal and distal colon. Retrograde labelled and microdissected dorsal root ganglia sensory neurons were used to evaluate TRPV1 gene transcription. Results showed that acute stress induces colonic hypersensitivity in MS but not in NH rats. Hypersensitivity was prevented by prestress administration of doxantrazole and anti-NGF. Capsazepine inhibited and SB-705498 reversed poststress hypersensitivity. In MS rats, acute stress induced a slight increase in colonic mast cell numbers without further signs of inflammation. Post-WA TRPV1 transcription and expression was not higher in MS than NH rats. In conclusion, the present data on stress-induced visceral hypersensitivity confirm earlier reports on the essential role of mast cells and NGF. Moreover, the results also suggest that TRPV1 modulation (in the absence of overt inflammation) is involved in this response. Thus, mast cells and TRPV1 are potential targets to treat stress-induced visceral hypersensitivity.

Decreased levels of the gelsolin plasma isoform in patients with rheumatoid arthritis

INTRODUCTION

Gelsolin is an intracellular actin-binding protein involved in cell shape changes, cell motility, and apoptosis. An extracellular gelsolin isoform, plasma gelsolin circulates in the blood of healthy individuals at a concentration of 200 +/- 50 mg/L and has been suggested to be a key component of an extracellular actin-scavenging system during tissue damage. Levels of plasma gelsolin decrease during acute injury and inflammation, and administration of recombinant plasma gelsolin to animals improves outcomes following sepsis or burn injuries. In the present study, we investigated plasma gelsolin in patients with rheumatoid arthritis.

METHODS

Circulating and intra-articular levels of plasma gelsolin were measured in 78 patients with rheumatoid arthritis using a functional (pyrene-actin nucleation) assay and compared with 62 age- and gender-matched healthy controls.

RESULTS

Circulating plasma gelsolin levels were significantly lower in patients with rheumatoid arthritis compared with healthy controls (141 +/- 32 versus 196 +/- 40 mg/L, P = 0.0002). The patients' intra-articular plasma gelsolin levels were significantly lower than in the paired plasma samples (94 +/- 24 versus 141 +/- 32 mg/L, P = 0.0001). Actin was detected in the synovial fluids of all but four of the patients, and immunoprecipitation experiments identified gelsolin-actin complexes.

CONCLUSIONS

The plasma isoform of gelsolin is decreased in the plasma of patients with rheumatoid arthritis compared with healthy controls. The reduced plasma concentrations in combination with the presence of actin and gelsolin-actin complexes in synovial fluids suggest a local consumption of this potentially anti-inflammatory protein in the inflamed joint.

Galectin-9 suppresses the generation of Th17, promotes the induction of regulatory T cells, and regulates experimental autoimmune arthritis

The effects of galectin-9 on a mouse collagen-induced arthritis (CIA) model were assessed to clarify whether galectin-9 suppresses CIA by regulating T cell immune responses. Galectin-9 suppressed CIA in a dose-dependent manner, and such suppression was observed even when treatment was started on 7 days after the booster, indicating its preventive and therapeutic effects. Galectin-9 induced the decreased levels of pro-inflammatory cytokines, IL-17, IL-12, and IFNgamma in the joint. Galectin-9 induced the decreased number of CD4(+) TIM-3(+) T cells in peripheral blood. Galectin-9-deficient mice became susceptible to CIA may be by increased number of CD4(+) TIM-3(+) T cells and decreased number of Treg cells. We further found that galectin-9 induces differentiation of naive T cells to Treg cells, and it suppresses differentiation to Th17 cells in vitro. The present results suggested that galectin-9 ameliorates CIA by suppressing the generation of Th17, promoting the induction of regulatory T cells.

Phase I evaluation of the safety, pharmacokinetics and pharmacodynamics of CP-481,715

BACKGROUND AND OBJECTIVES

The chemokine receptor CCR1 is believed to play a role in several inflammatory diseases, primarily by promoting the migration of leukocytes through the endothelial barrier. Thus, a possible strategy for treating inflammatory diseases is inhibition of leukocyte infiltration by antagonising CCR1. Recently, CP-481,715 has been described as a potent and specific antagonist of CCR1. The aims of this study were to assess the safety, pharmacokinetics and pharmacodynamics of CP-481,715 along with drug interactions with ciclosporin.

SUBJECTS AND METHODS

This was a phase I randomised, double-blind, placebo-controlled study with CP-481,715 in 78 healthy male volunteers. Subjects were administered escalating CP-481,715 doses of up to 3000 mg with food and after fasting in the single-dose study. In the drug interaction study, which was a single-dose, two-way crossover study, 12 subjects received a 300 mg dose of CP-481,715 as a suspension of polymorph A under fasted conditions, both with and without prior administration of ciclosporin.

RESULTS AND CONCLUSIONS

All doses of CP-481,715 were well tolerated, with linear pharmacokinetics up to the 300 mg dose. The pharmacodynamic activity of CP-481,715 was detected ex vivo by demonstrating a dose-related and linear increase in the amount of macrophage inflammatory protein-1alpha, CCL3, required to induce CD11b upregulation. Analysis of vital signs indicated no consistent clinical effects, and statistical analysis of ECG characteristics demonstrated no significant prolongation of the corrected QT interval. A drug-drug interaction study with ciclosporin demonstrated that CP-481,715 clearance was decreased by ciclosporin, consistent with its ability to compete with P-glycoprotein. Phase II studies may be warranted to see if CP-481,715 exhibits efficacy in treating inflammatory diseases such as rheumatoid arthritis, multiple sclerosis or transplant rejection.

Prothymosin α Lacking the Nuclear Localization Signal as an Effective Gene Therapeutic Strategy in Collagen-Induced Arthritis

Prothymosin alpha (ProT) is regulated by c-Myc, an oncoprotein overexpressed in synovium of rheumatoid arthritis, and is associated with cell proliferation. However, ProT also exerts immunomodulatory activities. The growth-promoting activity of ProT can be abolished by deleting its nuclear localization signal (NLS). In this study, we showed that AdProTDeltaNLS, an adenoviral vector encoding ProT lacking the NLS, did not enhance the proliferation of synovial fibroblasts. AdProTDeltaNLS treatment abolished the up-regulation of the MIP-1alpha promoter activity induced by TNF-alpha in synovial fibroblasts. AdProTDeltaNLS suppressed macrophage chemotaxis and reduced macrophage infiltration into the ankle joints in rats with collagen-induced arthritis (CIA). Neutralization test confirmed the involvement of MIP-1alpha in macrophage chemotaxis. Administration of AdProTDeltaNLS reduced the severity of CIA in the clinical, radiographic, and histological aspects. The levels of TNF-alpha (mean +/- SEM, 1261.9 +/- 107.9 vs 2880.1 +/- 561.4 pg/mg total protein; p < 0.05), IL-1beta (56.8 +/- 8.0 vs 109.2 +/- 4.9 pg/mg total protein; p < 0.01), and MIP-1alpha (41.7 +/- 3.6 vs 55.2 +/- 1.1 pg/mg total protein; p < 0.05) in the ankle joints were lower in the AdProTDeltaNLS-treated rats with CIA than those in their control counterparts. In the AdProTDeltaNLS-treated ankle joints, matrix metalloproteinase-9 expression was decreased by 40% and infiltrating macrophages reduced by 50%. Our results demonstrate that intra-articular delivery of AdProTDeltaNLS significantly ameliorated the clinical course of CIA in rats. This study is the first to suggest that ProT lacking the NLS may have therapeutic potential for the management of rheumatoid arthritis.

Triptolide inhibits CC chemokines expressed in rat adjuvant-induced arthritis

Triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F (TWHF), has been proven to have potent immunosuppressive and anti-inflammatory activities. It has been clinically used to treat patients with rheumatoid arthritis (RA), in which chemokines play an important role in immune and inflammatory responses. To investigate the effect of triptolide on MCP-1, MIP-1alpha and RANTES, we used complete Freund's adjuvant to induce adjuvant-induced arthritis (AA) in rats. AA in rat is a useful experimental model of human RA. Our data show that the thickness of arthritic ankle decreases with administration of triptolide. Both mRNA and protein levels of MCP-1, MIP-1alpha and RANTES in synovial tissue of rats with AA are significantly higher than those in normal rats. mRNA levels of MIP-1alpha and RANTES increase in peripheral blood mononuclear cells of rats with AA in comparison with those in normal rats, whereas no MCP-1 mRNA can be detected. Triptolide can significantly inhibit rat AA induced over-expression of MCP-1, MIP-1alpha and RANTES at both mRNA and protein levels in a dose-dependent manner. These results may contribute to the therapeutic effects of triptolide in rheumatoid arthritis.

Novel therapies for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease that causes significant morbidity and mortality. The pathogenesis outlined to date in RA consists of a cascade of pro-inflammatory cytokines and chemokines leading to the recruitment of inflammatory cells and the self perpetuation of inflammation, ultimately leading to cartilage and bone destruction. The dramatic progress in understanding the molecular immunology in RA has led to a transition from conventional treatment with aggressive immune suppression to targeted biological-based therapies that control the inflammatory pathways associated with RA. This article reviews the current biological and small-molecule therapies approved for the treatment of RA and those in development, including antibodies, tolerising agents and vaccines.

Proteomic analysis of secreted proteins in early rheumatoid arthritis: anti-citrulline autoreactivity is associated with up regulation of proinflammatory cytokines

OBJECTIVES

To identify peripheral blood autoantibody and cytokine profiles that characterise clinically relevant subgroups of patients with early rheumatoid arthritis using arthritis antigen microarrays and a multiplex cytokine assay.

METHODS

Serum samples from 56 patients with a diagnosis of rheumatoid arthritis of <6 months' duration were tested. Cytokine profiles were also determined in samples from patients with psoriatic arthritis (PsA) and ankylosing spondylitis (n = 21), and from healthy individuals (n = 19). Data were analysed using Kruskal-Wallis test with Dunn's adjustment for multiple comparisons, linear correlation tests, significance analysis of microarrays (SAM) and hierarchical clustering software.

RESULTS

Distinct antibody profiles were associated with subgroups of patients who exhibited high serum levels of tumour necrosis factor (TNF)alpha, interleukin (IL)1beta, IL6, IL13, IL15 and granulocyte macrophage colony-stimulating factor. Significantly increased autoantibody reactivity against citrullinated epitopes was observed in patients within the cytokine "high" subgroup. Increased levels of TNFalpha, IL1alpha, IL12p40 and IL13, and the chemokines eotaxin/CCL11, monocyte chemoattractant protein-1 and interferon-inducible protein 10, were present in early rheumatoid arthritis as compared with controls (p<0.001). Chemokines showed some of the most impressive differences. Only IL8/CXCL8 concentrations were higher in patients with PsA/ankylosing spondylitis (p = 0.02).

CONCLUSIONS

Increased blood levels of proinflammatory cytokines are associated with autoantibody targeting of citrullinated antigens and surrogate markers of disease activity in patients with early rheumatoid arthritis. Proteomic analysis of serum autoantibodies, cytokines and chemokines enables stratification of patients with early rheumatoid arthritis into molecular subgroups.

Biologic therapies in clinical development for the treatment of rheumatoid arthritis

The therapeutic objective in patients with rheumatoid arthritis (RA) is reduction of disease activity with an ultimate goal of disease remission. Limitations of currently available disease-modifying antirheumatic drugs and biologic therapies suggest that there remains an unmet need for agents that advance these goals in a greater proportion of patients. Progress in our understanding of the regulatory molecules and pathways that mediate the immune and inflammatory responses necessary for the initiation and perpetuation of RA has led to the identification of new targets for therapy. It is expected that the therapeutic modulation of these targets, which include proinflammatory cytokines, T and B cells, adhesion molecules, chemokines, and intra- and extracellular signaling pathways, can provide new treatment strategies in patients with RA and other autoimmune disorders. Toward this end, a series of novel agents with diverse mechanisms of action are in development. Although many of these agents are still beyond the clinical horizon, several of them have shown promise in recent trials. This article reviews a few of the many treatment strategies currently being evaluated, which are hoped to lead to greater benefits and better disease management in the clinical setting.

Prognostic significance of matrix metalloproteinase-7 in epithelial ovarian cancer and its relation to β-catenin expression

We investigated the expression and prognostic significance of matrix metalloproteinase (MMP) -7, its relation to beta-catenin expression and clinicopathological factors in epithelial ovarian cancer. The expression of MMP-7 was analyzed immunohistochemically in a series of 284 primary epithelial ovarian cancers, their 36 metastases and 8 normal ovaries. In cancers with endometrioid histology, a high percentage area of MMP-7 expression and an intense MMP-7 signal was significantly associated with nuclear positivity of beta-catenin in cancer cells (p = 0.003, chi2 = 8.853 and p = 0.030, chi2 = 4.713, respectively). In all tumors and nonendometrioid subgroup, a low percentage area of MMP-7 positive tumor cells was significantly correlated with a high histological grade of the tumor (p = 0.003 and 0.005, respectively), in all tumors also with advanced stage of the tumor (p = 0.002) and large primary residual tumor (p = 0.005). A 10-year disease-related survival (DRS) was significantly better when the percentage area of MMP-7 expression in cancer cells was high, when compared to low (p = 0.0008). A high percentage area of intense MMP-7 signal in cancer cells predicted a significantly more favorable DRS and recurrence-free survival (RFS) (p = 0.0003 and 0.0052, respectively). In multivariate analysis, a high percentage area of intense MMP-7 signal in tumor cells was an independent prognostic factor, predicting favorable DRS and RFS. The present study showed that intense MMP-7 signal in tumor cells is an independent prognostic factor predicting better survival in epithelial ovarian cancer.

Synovial biopsy

In patients with arthritis, synovial tissue is easily accessible for analysis. Blind needle biopsy is a simple and safe procedure. Arthroscopic biopsy is also safe, it allows access to most sites in the joint and it can provide adequate tissue for extensive laboratory investigations, both before and after successful therapy. Synovial tissue analysis has been successfully applied to the study of disease mechanisms and response to treatment. In addition, there may be an indication for diagnostic synovial biopsy in selected cases.

Expression and functional properties of antibodies to tissue inhibitors of metalloproteinases (TIMPs) in rheumatoid arthritis

Tissue inhibitors of matrix metalloproteinases (TIMPs) regulate the breakdown of extracellular matrix components and play an important role in tissue remodelling and growth, in both physiological and pathological conditions. We studied the autoimmune response to TIMPs in patients with rheumatoid arthritis (RA). Eighty-nine paired blood and synovial fluid samples from patients with RA were assessed for their reactivity with recombinant tissue inhibitors of metalloproteinases (TIMPs) 1 to 4 by an ELISA and were compared with blood from 62 healthy controls and 21 synovial fluid samples from patients with degenerative joint diseases. Presence of antibodies was established as the absorbance of the sample more than 2 standard deviations above the mean of the controls. In addition, immunoglobulin G (IgG) from blood samples of RA patients possessing TIMP antibodies was isolated on protein A-sepharose and tested for the in vitro ability to neutralize TIMP-2-dependent effects on metalloproteinase 9 (MMP9). Anti-TIMP antibodies were found in 56% of RA samples but in only 5% of the controls (P < 0.005). RA patients had high frequencies of antibodies against all TIMPs except TIMP-3. TIMP-2 antibodies were most frequently found (33%), being significantly more prevalent (P = 0.024) in patients with nonerosive than erosive RA. TIMP-1 antibodies were significantly more often found in synovial fluid samples than in the matched blood samples (P < 0.025). Importantly, the IgG fraction containing TIMP antibodies down-regulated the TIMP-2 inhibitory effect, thereby supporting MMP9 activity in vitro. In the present study, we show that RA patients frequently develop autoimmune response to TIMPs that may act as a functionally significant regulator of MMP activity and thereby of joint destruction.

Pathogenesis of rheumatoid arthritis: how early is early?

Studies of cytokine expression in rheumatoid arthritis have provided key insights into the pathogenesis of disease and have offered clues for effective therapy. Patterns of T-cell products in chronic rheumatoid synovitis suggest that T helper type 1 cells contribute to the perpetuation of disease. However, there is no guarantee that the mechanisms of late disease are identical to very early rheumatoid arthritis. Evaluation of the cytokine profile at the earliest time points after onset of symptoms could identify novel targets that prevent progression to chronic arthritis.

The presence of promatrix metalloproteinase-3 and its relation with different categories of coal workers' pneumoconiosis

Extracellular matrix formation (ECM) and remodeling are critical events related to the pathogenesis of pulmonary fibrosis. Matrix metalloproteinases play an essential role in degrading and remodeling the ECM. In this study, we tried to show the presence and correlation of promatrix metalloproteinase-3 (proMMP-3) (the inactive form of metalloproteinase-3) levels in coal workers' pneumoconiosis (CWP) with different categories. The study population consisted of 44 coal miners with CWP (pos CWP). Coal miners without CWP (neg CWP, n = 24) and non-underground personnel (controls, n = 17) were taken as controls. All coal miners were stable and had no systemic infection or disease. Standard posterio-anterior chest radiographs and pulmonary function tests were performed to exclude any diseases other than CWP. Serum proMMP-3 was analysed using the sandwich enzyme-linked immunosorbent assay according to the manufacturer's instructions (The Binding Site, Birmingham, UK). Mean proMMP-3 values of the all three groups were compared and a significant statistical difference obtained (p < 0.001). In addition, a statistically significant difference was found between categories of the disease and proMMP-3 values (p < 0.05). The effects of age, exposure duration and cigarette smoking on proMMP-3 values in coal miners with CWP were investigated. There were no correlations between age, smoking and proMMP-3 values. However, a positive correlation was found between exposure duration and proMMP-3 values (r = 0.447, p = 0.008). In conclusion, proMMP-3 (prostromelysin 1) may play an essential role in degrading and remodeling the ECM in workers with pneumoconiosis. ProMMP-3 may also reflect the stage of pneumoconiosis disease.

Ginger extract components suppress induction of chemokine expression in human synoviocytes

INTRODUCTION

Ginger has a long history of medicinal use, particularly as an anti-inflammatory agent for a wide variety of diseases such as arthritis. Suppression of inflammation in arthritis is attributed to suppression of proinflammatory cytokines and chemokines produced by synoviocytes, chondrocytes, and leukocytes.

OBJECTIVE

This study aimed to elucidate the effect of a combination ginger extract and its individual components on chemokine expression in human synoviocytes.

METHODS

Human synoviocytes were incubated with 100 microg/mL combination ginger extract (GE) of Alpinia galanga (AG) and Zingiber officinale (ZO); AG extract alone; ZO extract alone; or control media, for 1 hour at 37 degrees C, 5% CO2. Cells were next activated with 1 ng/mL of tumor necrosis factor alpha (TNF-alpha) for 1 hour to determine macrophage chemotactic factor (MCP-1) and interferon-gamma activated protein (IP-10) mRNA levels using reverse transcriptase polymerase chain reaction (RT-PCR). Secreted MCP-1 and IP-10 were quantified by enzyme-linked immunosorbent assay (ELISA) following a 24 hour incubation period.

RESULTS

The GE combination was consistently more effective in decreasing chemokine mRNA and chemokine secreted protein levels than its individual components ZO or AG. In comparison, ZO was more effective than AG in suppressing chemokine expression.

CONCLUSION

The present study demonstrates that GE inhibits chemokine expression, and that the combination of ZO and AG components acts synergistically. This ginger formulation may be useful for suppressing inflammation due to arthritis.

Differential expression and response to anti-TNFα treatment of infiltrating versus resident tissue macrophage subsets in autoimmune arthritis

Synovial macrophages play a pivotal role in the pathogenesis of chronic autoimmune arthritis by contributing to local inflammation and tissue damage and are therefore a primary target for therapeutic intervention. The aim of the present study was to investigate in more detail the relative contribution of different synovial macrophage subsets with potentially different inflammatory or anti-inflammatory functions by analysing the two most frequent forms of human autoimmune arthritis, spondyloarthropathy (SpA) and rheumatoid arthritis (RA). Both infiltrating macrophages from peripheral blood expressing myeloid-related proteins (MRP) 8 and 14, and resident tissue macrophages expressing CD163 were abundant in inflamed synovium. Whereas the global number of synovial macrophages was similar in both diseases, infiltrating macrophages were increased in the RA lining layer in contrast with resident tissue macrophages, which were more frequently observed in SpA. Soluble MRP8/MRP14 complexes, which were secreted locally in the joint during the infiltration process, were increased in the serum of arthritis patients and, in contrast with soluble CD163 shed from resident tissue macrophages, correlated well with global inflammatory parameters. Treatment in vivo with anti-TNFalpha had a rapid and pronounced effect on the infiltration of MRP-positive macrophages into tissues, as evidenced by histopathological analysis and serum MRP8/MRP14 levels. Taken together, these data support an important role for infiltrating versus resident tissue macrophages in human autoimmune synovitis and indicate that macrophage products such as soluble MRP8/MRP14 complexes are valuable biomarkers for the experimental and clinical monitoring of specific disease mechanisms in vivo.

Chemokine secretion of rheumatoid arthritis synovial fibroblasts stimulated by Toll-like receptor 2 ligands

To analyze the role of Toll-like receptors (TLR) in the pathogenesis of rheumatoid arthritis, we have assessed the effects of stimulation of cultured synovial fibroblasts by the TLR-2 ligand bacterial peptidoglycan. By using high density oligonucleotide microarray analysis we identified 74 genes that were up-regulated >2.5-fold. Fourteen CC and CXC chemokine genes were among the genes with the highest up-regulation. Quantitative real-time PCR analysis confirmed up-regulation of granulocyte chemotactic protein (GCP)-2, RANTES, monocyte chemoattractant protein (MCP)-2, IL-8, growth-related oncogene-2, and to a lesser extent, macrophage-inflammatory protein 1alpha, MCP-1, EXODUS, and CXCL-16. GCP-2, RANTES, and MCP-2 were detected in culture supernatants of synovial fibroblasts stimulated with peptidoglycan. Chemokine secretion induced by stimulation of rheumatoid arthritis synovial fibroblasts via TLR-2 was functionally relevant as demonstrated by chemotaxis assays. GCP-2 and MCP-2 expression, which have not been reported previously in rheumatoid arthritis, was demonstrated in synovial tissue sections of patients diagnosed with rheumatoid arthritis but not in those with osteoarthritis. Correspondingly, synovial fluid levels were significantly higher in patients diagnosed with rheumatoid arthritis as compared with osteoarthritis. Thus, we present evidence for an induction of chemokine secretion by activation of synovial fibroblasts via TLR-2, possibly contributing to the formation of inflammatory infiltrates characteristically found in rheumatoid arthritis joints.

Identification and Characterization of 4-[[4-(2-Butynyloxy)phenyl]sulfonyl]-N-hydroxy-2,2-dimethyl-(3S)thiomorpholinecarboxamide (TMI-1), a Novel Dual Tumor Necrosis Factor-α-Converting Enzyme/Matrix Metalloprotease Inhibitor for the Treatment of Rheumatoid Arthritis

Tumor necrosis factor (TNF)-alpha is a well validated therapeutic target for the treatment of rheumatoid arthritis. TNF-alpha is initially synthesized as a 26-kDa membrane-bound form (pro-TNF) that is cleaved by a Zn-metalloprotease named TNF-alpha-converting enzyme (TACE) to generate the 17-kDa, soluble, mature TNF-alpha. TACE inhibitors that prevent the secretion of soluble TNF-alpha may be effective in treating rheumatoid arthritis (RA) patients. Using a structure-based design approach, we have identified a novel dual TACE/matrix metalloprotease (MMP) inhibitor 4-[[4-(2-butynyloxy)phenyl]sulfonyl]-N-hydroxy-2,2-dimethyl-(3S)thiomorpholinecarboxamide (TMI-1). This molecule inhibits TACE and several MMPs with nanomolar IC(50) values in vitro. In cell-based assays such as monocyte cell lines, human primary monocytes, and human whole blood, it inhibits lipopolysaccharide (LPS)-induced TNF-alpha secretion at submicromolar concentrations, whereas there is no effect on the TNF-alpha mRNA level as judged by RNase protection assay. The inhibition of LPS-induced TNF-alpha secretion is selective because TMI-1 has no effect on the secretion of other proinflammatory cytokines such as interleukin (IL)-1beta, IL-6, and IL-8. Importantly, TMI-1 potently inhibits TNF-alpha secretion by human synovium tissue explants of RA patients. In vivo, TMI-1 is highly effective in reducing clinical severity scores in mouse prophylactic collagen-induced arthritis (CIA) at 5, 10, and 20 mg/kg p.o. b.i.d. and therapeutic CIA model at 100 mg/kg p.o. b.i.d. In summary, TMI-1, a dual TACE/MMP inhibitor, represents a unique class of orally bioavailable small molecule TNF inhibitors that may be effective and beneficial for treating RA.

Involvement of matrix metalloproteinases and their inhibitors in peripheral synovitis and down-regulation by tumor necrosis factor ? blockade in spondylarthropathy

OBJECTIVE

To investigate the role of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in spondylarthropathy (SpA) synovitis.

METHODS

Paired samples of synovial biopsy tissue as well as serum and synovial fluid (SF) from 41 patients with SpA and 20 patients with rheumatoid arthritis (RA) and serum samples from 20 healthy controls were analyzed by immunohistochemistry and enzyme-linked immunosorbent assay for the presence of MMPs 1, 2, 3, and 9 and TIMPs 1 and 2. In addition, sera from 16 patients with ankylosing spondylitis (AS) and peripheral synovitis and 17 patients with AS and exclusively axial involvement were analyzed. An additional cohort of SpA patients was analyzed at baseline and after 12 weeks of infliximab treatment.

RESULTS

Staining for MMPs and TIMPs showed a cellular and interstitial pattern in the synovial lining and sublining layers that was similar between the RA and SpA patients. Involvement of MMPs and TIMPs in SpA synovitis was suggested by the correlation with cellular infiltration, vascularization, and cartilage degradation. Higher serum levels of MMPs 3 and 9 were revealed in SpA and RA patients as compared with healthy controls. Production of MMP-3, but not MMP-9, in the serum reflected the presence of peripheral synovitis, as indicated by 1) the correlation between serum levels, SF levels (which were 1,000-fold higher than the serum levels), and synovial expression of MMP-3, 2) the increased levels of MMP-3 in AS patients with peripheral disease and not exclusively axial involvement, and 3) the correlation of serum and SF MMP-3 with parameters of synovial, but not systemic, inflammation. The modulation of the MMP/TIMP system by tumor necrosis factor alpha (TNFalpha) blockade was confirmed by the down-regulation of all MMPs and TIMPs in the synovium and a pronounced and rapid decrease of serum MMP-3.

CONCLUSION

MMPs and TIMPs are highly expressed in SpA synovitis and mirror both the inflammatory and tissue-remodeling aspects of the local disease process. Serum MMP-3, originating from the inflamed joint, represents a valuable biomarker for peripheral synovitis. Modulation of the MMP/TIMP system by infliximab could contribute to the antiinflammatory and tissue-remodeling effects of TNFalpha blockade in SpA.

CP-481,715, a potent and selective CCR1 antagonist with potential therapeutic implications for inflammatory diseases

The chemokines CCL3 and CCL5, as well as their shared receptor CCR1, are believed to play a role in the pathogenesis of several inflammatory diseases including rheumatoid arthritis, multiple sclerosis, and transplant rejection. In this study we describe the pharmacological properties of a novel small molecular weight CCR1 antagonist, CP-481,715 (quinoxaline-2-carboxylic acid [4(R)-carbamoyl-1(S)-(3-fluorobenzyl)-2(S),7-dihydroxy-7-methyloctyl]amide). Radiolabeled binding studies indicate that CP-481,715 binds to human CCR1 with a Kd of 9.2 nm and displaces 125I-labeled CCL3 from CCR1-transfected cells with an IC50 of 74 nm. CP-481,715 lacks intrinsic agonist activity but fully blocks the ability of CCL3 and CCL5 to stimulate receptor signaling (guanosine 5'-O-(thiotriphosphate) incorporation; IC50 = 210 nm), calcium mobilization (IC50 = 71 nm), monocyte chemotaxis (IC50 = 55 nm), and matrix metalloproteinase 9 release (IC50 = 54 nm). CP-481,715 retains activity in human whole blood, inhibiting CCL3-induced CD11b up-regulation and actin polymerization (IC50 = 165 and 57 nm, respectively) on monocytes. Furthermore, it behaves as a competitive and reversible antagonist. CP-481,715 is >100-fold selective for CCR1 as compared with a panel of G-protein-coupled receptors including related chemokine receptors. Evidence for its potential use in human disease is suggested by its ability to inhibit 90% of the monocyte chemotactic activity present in 11/15 rheumatoid arthritis synovial fluid samples. These data illustrate that CP-481,715 is a potent and selective antagonist for CCR1 with therapeutic potential for rheumatoid arthritis and other inflammatory diseases.

Chemokine blockade and chronic inflammatory disease: proof of concept in patients with rheumatoid arthritis

BACKGROUND

Chemokines and their receptors are considered important contributors in cell migration and inflammation in chronic inflammatory disorders. Chemokines affecting monocytes/macrophages are considered potential therapeutic targets, but no studies of the effects of blocking the chemokine repertoire in humans with a chronic inflammatory disease have been reported.

OBJECTIVE

To carry out a double blind, placebo controlled, phase Ib clinical trial with a specific, oral CCR1 antagonist.

METHODS

16 patients with active rheumatoid arthritis (RA) were randomised 3:1 to active:placebo treatment for 14 days. Synovial biopsy specimens were obtained on days 1 and 15. Immunohistochemistry was used to detect the presence of various cell types before and after treatment and the results measured by digital image analysis. Results before and after treatment were compared by paired t test, and a two sample t test was used to compare the changes from baseline in the two groups.

RESULTS

All patients completed the study. A significant reduction in the number of macrophages (p=0.016), intimal macrophages (p=0.026), and CCR1+cells (p=0.049) in patients treated with the chemokine antagonist compared with the placebo group occurred in the synovium. Significant decreases in overall cellularity, intimal lining layer cellularity, CD4+ T cells, and CD8+ T cells also occurred in treated patients. Cells lacking CCR1 were not affected. Trends towards clinical improvement were seen in the treated patients but not in the placebo group. Severe side effects were not reported.

CONCLUSION

Specific chemokine receptor blockade can result in relevant biological effects in patients with active RA.

Suppressive effect of combination treatment of leflunomide and methotrexate on chemokine expression in patients with rheumatoid arthritis

To study the immunosuppressive and anti-inflammatory effects of combined leflunomide and methotrexate (MTX) therapy on chemokine expression in patients with rheumatoid arthritis (RA), nine patients were enrolled for the combination therapy for 24 weeks. These patients have been on treatment with MTX 15 mg/week for not less than 3 months before entry to the study. A loading dose of l00 mg/day of leflunomide was given for 3 days, followed by 10 mg/day for the rest of the study period. Plasma concentrations of monocyte chemotactic protein-1 (MCP-1), thymus- and activation-regulated chemokine (TARC), and macrophage-derived chemokine (MDC) were assayed before and after combination treatment by ELISA. Gene expression of inflammatory cytokines and chemokines of peripheral blood mononuclear cells was analysed by cDNA expression array. Plasma MCP-1, TARC and MDC concentrations were significantly lower in patients after combination treatment [median (interquartile range) before versus after treatment: MCP-1 of 118.0 (64.0-515.2) versus 3.2 (0.0-22.8) pg/ml, P < 0.01; TARC of 126.1 (27.2-197.4) versus 0.0 (0.0-52.5) pg/ml, P < 0.05; MDC of 503.3 (446.2-600.9) versus 366.8 (337.4-393.4) pg/ml, P < 0.05]. Positive correlations among reductions in plasma chemokines and clinical outcome measures were also found. Expression of chemokine genes including MDC and TARC was suppressed after combination treatment [% suppression of 38.7 (54.3-13.0) and 53.7 (55.9-28.4), respectively]. Combination therapy with leflunomide and MTX exhibits anti-inflammatory activity in the suppression of chemokine expression and subsequent recruitment of inflammatory cells into the inflammatory sites in RA.

Expression of the dendritic cell-associated C-type lectin DC-SIGN by inflammatory matrix metalloproteinase-producing macrophages in rheumatoid arthritis synovium and interaction with intercellular adhesion molecule 3-positive T cells

OBJECTIVE

To determine whether matrix metalloproteinase (MMP)-producing inflammatory macrophages in the synovium of rheumatoid arthritis (RA) patients express the novel dendritic cell (DC)-specific C-type lectin DC-SIGN and whether this expression is associated with the presence of naive T cells expressing the DC-SIGN ligand, intercellular adhesion molecule 3 (ICAM-3).

METHODS

Reverse transcription-polymerase chain reaction was performed to study the expression of DC-SIGN in synovium samples from RA, osteoarthritis (OA), and trauma patients. DC-SIGN expression on RA monocytes or on monocytes stimulated with granulocyte-macrophage colony-stimulating factor and interleukin-4 was further investigated by flow cytometry. To localize DC-SIGN in the synovium, the DC markers ICAM-3 and MMP-1 were analyzed by immunohistochemistry (single and double labeling) on serial cryostat sections.

RESULTS

Seventy percent of the inflammatory cells in the synovium of RA patients showed high expression of DC-SIGN. DC-SIGN was expressed by 80% of CD68-positive macrophages, but not by CD83-positive, DC-LAMP-positive, or Fascin-positive cells. Normal numbers of DC-SIGN-positive cells were found in the peripheral blood of RA patients, suggesting that DC-SIGN is up-regulated locally in the joint. In RA synovium, ICAM-3-positive resting T cells were found in close proximity to DC-SIGN cells. Unexpectedly, a lower percentage of DC-SIGN-expressing cells was found in OA synovium compared with RA synovium. Furthermore, ICAM-3-expressing T cells, which are known to bind DC-SIGN, were almost absent within the synovium of OA and trauma patients. DC-SIGN-positive macrophages adjacent to these T cells were located in close proximity to the cartilage-degrading proteins extracellular MMP inducer (EMMPRIN) and MMP-1.

CONCLUSION

The C-type lectin DC-SIGN is almost absent in the synovium of trauma patients but is highly expressed by most CD68-positive macrophages in the synovium of RA patients. The lack of correlation between DC-SIGN expression and the expression of CD83, DC-LAMP, or Fascin indicates that multiple DC/macrophage subsets are present in RA synovium. Expression of DC-SIGN and its ligand, ICAM-3, is found in substantial amounts only in RA synovium, suggesting that their interaction is implicated in the additional activation of synovial macrophages that leads to the production of EMMPRIN and MMP-1.