Interferon-beta for treatment of rheumatoid arthritis?

Treatment of autoimmunity: The impact of disease-modifying therapies in multiple sclerosis and comorbid autoimmune disorders

More than 10 disease-modifying therapies (DMT) are approved by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for the treatment of multiple sclerosis (MS) and new therapeutic options are on the horizon. Due to different underlying therapeutic mechanisms, a more individualized selection of DMTs in MS is possible, taking into account the patient's current situation. Therefore, concomitant treatment of various comorbid conditions, including autoimmune mediated disorders such as rheumatoid arthritis, should be considered in MS patients. Because the pathomechanisms of autoimmunity partially overlap, DMT could also treat concomitant inflammatory diseases and simplify the patient's treatment. In contrast, the exacerbation and even new occurrence of several autoimmune diseases have been reported as a result of immunomodulatory treatment of MS. To simplify treatment and avoid disease exacerbation, knowledge of the beneficial and adverse effects of DMT in other autoimmune disorders is critical. Therefore, we conducted a literature search and described the beneficial and adverse effects of approved and currently studied DMT in a large number of comorbid autoimmune diseases, including rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel diseases, cutaneous disorders including psoriasis, Sjögren´s syndrome, systemic lupus erythematosus, systemic vasculitis, autoimmune hepatitis, and ocular autoimmune disorders. Our review aims to facilitate the selection of an appropriate DMT in patients with MS and comorbid autoimmune diseases.

Ocular immune privilege and retinal pigment epithelial cells

The ocular tissue microenvironment is immune-privileged and uses multiple immunosuppressive mechanisms to prevent the induction of inflammation. The retinal pigment epithelium plays an essential role in ocular immune privilege. In addition to serving as a blood barrier separating the fenestrated choriocapillaris from the retina, the retinal pigment epithelium is a source of immunosuppressive cytokines and membrane-bound negative regulators that modulate the activity of immune cells within the retina. This article reviews the current understanding of how retinal pigment epithelium cells mediate immune regulation, focusing on the changes under pathologic conditions.

Serum level of IFNβ distinguishes early from late relapses after biologics withdrawal in rheumatoid arthritis

Since the advent of biological disease modifying anti-rheumatic drugs (bDMARDs) in the treatment of rheumatoid arthritis (RA), most RA patients receiving such drugs have achieved remission at the expense of cost and infection risk. After bDMARDs are withdrawn, a substantial proportion of patients would have relapses even if they were in complete remission. In our previous report, relapse prediction could be made at the time of bDMARD withdrawal by measuring the serum levels of five cytokines. We report herein that, among 73 cytokines examined, serum levels of only interferon β (IFNβ) at the time of bDMARD withdrawal could predict early relapse (within 5 months) in patients who were categorized to relapse by the five cytokines in our previous report, with a cut-off value of 3.38 in log₂ and AUC of 0.833. High serum levels of IFNβ in the early-relapse group remained high until actual relapse occurred. Therefore, patients who relapse early might be biochemically different from those who relapse late or do not relapse at all. We recommend that patients who are predicted to relapse early continue bDMARDs even if they are in complete remission. This finding contributes to shared decision-making regarding how and when bDMARDs should be discontinued.

Mitochondrial double-stranded RNAs govern the stress response in chondrocytes to promote osteoarthritis development

Protein kinase R (PKR) is an immune response protein that becomes activated by double-stranded RNAs (dsRNAs). PKR overactivation is associated with degenerative diseases with inflammation, including osteoarthritis (OA), but the dsRNA activator remains largely unknown. Here, we find that mitochondrial dsRNA (mt-dsRNA) expression and its cytosolic efflux are facilitated in chondrocytes under OA-eliciting conditions, leading to innate immune activation. Moreover, mt-dsRNAs are released to the extracellular space and activate Toll-like receptor 3 at the plasma membrane. Elevated levels of mt-dsRNAs in the synovial fluids and damaged cartilage of OA patients and in the cartilage of surgery-induced OA mice further support our data. Importantly, autophagy prevents PKR activation and protects chondrocytes from mitochondrial stress partly by removing cytosolic mtRNAs. Our study provides a comprehensive understanding of innate immune activation by mt-dsRNAs during stress responses that underlie the development of OA and suggests mt-dsRNAs as a potential target for chondroprotective intervention.

Administration of an adeno-associated viral vector expressing interferon-β in patients with inflammatory hand arthritis, results of a phase I/II study

OBJECTIVE

Inflammatory hand arthritis (IHA) results in impaired function. Local gene therapy with ART-I02, a recombinant adeno-associated virus (AAV) serotype 5 vector expressing interferon (IFN)-β, under the transcriptional control of nuclear factor κ-B responsive promoter, was preclinically shown to have favorable effects. This study aimed to investigate the safety and tolerability of local gene therapy with ART-I02 in patients with IHA.

METHODS

In this first-in-human, dose-escalating, cohort study, 12 IHA patients were to receive a single intra-articular (IA) injection of ART-I02 ranging 0.3 × 10¹²-1.2 × 10¹³ genome copies in an affected hand joint. Adverse events (AEs), routine safety laboratory and the clinical course of disease were periodically evaluated. Baseline- and follow-up contrast enhanced magnetic resonance images (MRIs), shedding of viral vectors in bodily fluids, and AAV5 and IFN-β immune responses were evaluated. A data review committee provided safety recommendations.

RESULTS

Four patients were enrolled. Long-lasting local AEs were observed in 3 patients upon IA injection of ART-I02. The AEs were moderate in severity and could be treated conservative. Given the duration of the AEs and their possible or probable relation to ART-I02, no additional patients were enrolled. No systemic treatment emergent AEs were observed. The MRIs reflected the AEs by (peri)arthritis. No T-cell response against AAV5 or IFN-β, nor IFN-β antibodies could be detected. Neutralizing antibody titers against AAV5 raised post-dose.

CONCLUSION

Single IA doses of 0.6 × 10¹² or 1.2 × 10¹² ART-I02 vector genomes were administered without systemic side effects or serious AEs. However, local tolerability was insufficient for continuation.

TRIAL REGISTRATION

NCT02727764.

A comprehensive transcriptomic analysis of alternate interferon signaling pathways in peripheral blood mononuclear cells in rheumatoid arthritis

Interferon (IFN) signaling pathways play crucial roles in the pathogenesis of rheumatoid arthritis (RA). Prior studies have mainly studied mixed alterations in the IFN signaling pathway in RA, but these studies have not been sufficient to elucidate how imbalanced IFN signaling subtly influences immune cells. Single-cell RNA (scRNA) sequencing makes it possible to better understand the alternations in the interferon signaling pathways in RA. In the present study, we found that IFN signaling pathways were activated in natural killer (NK) cells, monocytes, T cells, B cells, and most immune cell subclasses in RA. We then explored and analyzed the connections between abnormal IFN signaling pathways and cellular functional changes in RA. Single-Cell rEgulatory Network Inference and Clustering (SCENIC) analysis and gene regulatory network (GRN) construction were also performed to identify key transcription factors in RA. Finally, we also investigated altered IFN signaling pathways in multiple RA peripheral blood samples, which indicated that abnormal IFN signaling pathways were universally observed in RA. Our study contributes to a better understanding of the delicate and precise regulation of IFN signaling in the immune system in RA. Furthermore, common alternations in IFN signaling pathway-related transcription factors could help to identify novel therapeutic targets for RA treatment.

IFN-β Acts on Monocytes to Ameliorate CNS Autoimmunity by Inhibiting Proinflammatory Cross-Talk Between Monocytes and Th Cells

IFN-β has been the treatment for multiple sclerosis (MS) for almost three decades, but understanding the mechanisms underlying its beneficial effects remains incomplete. We have shown that MS patients have increased numbers of GM-CSF+ Th cells in circulation, and that IFN-β therapy reduces their numbers. GM-CSF expression by myelin-specific Th cells is essential for the development of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. These findings suggested that IFN-β therapy may function via suppression of GM-CSF production by Th cells. In the current study, we elucidated a feedback loop between monocytes and Th cells that amplifies autoimmune neuroinflammation, and found that IFN-β therapy ameliorates central nervous system (CNS) autoimmunity by inhibiting this proinflammatory loop. IFN-β suppressed GM-CSF production in Th cells indirectly by acting on monocytes, and IFN-β signaling in monocytes was required for EAE suppression. IFN-β increased IL-10 expression by monocytes, and IL-10 was required for the suppressive effects of IFN-β. IFN-β treatment suppressed IL-1β expression by monocytes in the CNS of mice with EAE. GM-CSF from Th cells induced IL-1β production by monocytes, and, in a positive feedback loop, IL-1β augmented GM-CSF production by Th cells. In addition to GM-CSF, TNF and FASL expression by Th cells was also necessary for IL-1β production by monocyte. IFN-β inhibited GM-CSF, TNF, and FASL expression by Th cells to suppress IL-1β secretion by monocytes. Overall, our study describes a positive feedback loop involving several Th cell- and monocyte-derived molecules, and IFN-β actions on monocytes disrupting this proinflammatory loop.

Biomarker Approach Towards Rheumatoid Arthritis Treatment

Rheumatoid arthritis is an auto-immune disorder, recognized by cartilage as well as bone destruction, which causes irreversible joint deformities, which further results in functional limitations in the patient. Genes like HLA-DRB1 and PTPN22 are likely implicated in the genetic predisposition of rheumatoid arthritis pathology. The first and foremost clinical manifestation in a person with rheumatoid arthritis is joint destruction followed by cartilage and bone destruction caused by cell-cell interactions. The cell-cell interactions are thought to be initialized through the contact of antigen-presenting cells (APC) with CD4+ cells, leading to the progression of the disease. APC includes a complex of class ІІ major histocompatibility complex molecules along with peptide antigens and binds to the receptors present on the surface of T-cells. Further, the activation of macrophages is followed by the release of various pro-inflammatory cytokines such as IL-1 and TNF-α, which lead to the secretion of enzymes that degrade proteoglycan and collagen, which in turn, increase tissue degradation. Biomarkers like IL-6, IL-12, IL-8 and IL-18, 14-3-3η, RANKL, IFN-γ, IFN-β and TGF-β have been designated as key biomarkers in disease development and progression. The study of these biomarkers is very important as they act as a molecular indicator of pathological processes that aggravate the disease.

Structure and Pathologies of Articular Cartilage

The aim of the review was to describe a complex microstructure and biomechanical properties of the articular cartilage as well as a current review of its pathologies encountered in veterinary practice. The articular cartilage with its unique features: complex microarchitecture, significant mechanical durability and elasticity, lacking blood, lymphatic vessels, and innervation, seems to stand in contradiction to the laws of biology. It can be involved in a vast majority of diseases, from osteoarthrosis as a result of natural aging process to more complex in nature like osteochondromatosis. The primary role of articular cartilage is to provide the surface for movement in any single joint in the body. Therefore, its diseases lead to physical impairment and deterioration of the quality of life. Treatment of articular cartilage poses a formidable challenge in both modern human and animal medicine.

Tolerizing Strategies for the Treatment of Autoimmune Diseases: From ex vivo to in vivo Strategies

Autoimmune diseases such as multiple sclerosis (MS), type I diabetes (T1D), inflammatory bowel diseases (IBD), and rheumatoid arthritis (RA) are chronic, incurable, incapacitating and at times even lethal conditions. Worldwide, millions of people are affected, predominantly women, and their number is steadily increasing. Currently, autoimmune patients require lifelong immunosuppressive therapy, often accompanied by severe adverse side effects and risks. Targeting the fundamental cause of autoimmunity, which is the loss of tolerance to self- or innocuous antigens, may be achieved via various mechanisms. Recently, tolerance-inducing cellular therapies, such as tolerogenic dendritic cells (tolDCs) and regulatory T cells (Tregs), have gained considerable interest. Their safety has already been evaluated in patients with MS, arthritis, T1D, and Crohn’s disease, and clinical trials are underway to confirm their safety and therapeutic potential. Cell-based therapies are inevitably expensive and time-consuming, requiring laborious ex vivo manufacturing. Therefore, direct in vivo targeting of tolerogenic cell types offers an attractive alternative, and several strategies are being explored. Type I IFN was the first disease-modifying therapy approved for MS patients, and approaches to endogenously induce IFN in autoimmune diseases are being pursued vigorously. We here review and discuss tolerogenic cellular therapies and targeted in vivo tolerance approaches and propose a novel strategy for cell-specific delivery of type I IFN signaling to a cell type of choice.

Haptoglobin Acts as a TLR4 Ligand to Suppress Osteoclastogenesis via the TLR4-IFN-β Axis

Haptoglobin (Hp), a type of acute-phase protein, is known to have a systemic anti-inflammatory function and to modulate inflammation by directly affecting immune cells, such as T cells, dendritic cells, and macrophages. However, the effects of Hp on osteoclast differentiation are not well studied, even though osteoclast precursor cells belong to a macrophage-monocyte lineage. In this study, we found that the bone volume was reduced, and the number of osteoclasts was increased in Hp-deficient mice compared with wild-type mice. Moreover, our in vitro studies showed that Hp inhibits osteoclastogenesis by reducing the protein level of c-Fos at the early phase of osteoclast differentiation. We revealed that Hp-induced suppression of c-Fos was mediated by increased IFN-β levels. Furthermore, Hp stimulated IFN-β via a TLR4-dependent mechanism. These results demonstrate that Hp plays a protective role against excessive osteoclastogenesis via the Hp-TLR4-IFN-β axis.

DNA-Mediated Interferon Signature Induction by SLE Serum Occurs in Monocytes Through Two Pathways: A Mechanism to Inhibit Both Pathways

A primary mechanism for activation of innate immunity is recognition of damage or pathogen associated molecular patterns by pattern recognition receptors (PRRs). Nucleic acid is a damage associated molecular pattern molecule that when internalized into a monocyte and recognized by intracellular nucleic acid sensing toll like receptors will cause production of type 1 interferon. The process by which DNA or RNA is delivered into the cytosol of monocytes in systemic lupus erythematosus remains incompletely understood, and therapeutic approaches to prevent DNA-mediated monocyte activation are needed. We identified two mechanisms for internalization of DNA by monocytes. IgG-bound DNA was internalized by interacting with Fc gamma receptor IIa, while high-mobility group box-1 protein-bound DNA was internalized by interacting with the receptor for advanced glycation end products. Both pathways contribute to an inflammatory phenotype in monocytes exposed to serum from patients with SLE. Moreover, both of these pathways can be inhibited by a pentapeptide, DWEYS, which is a DNA mimetope. In one instance DWEYS directly competes with DNA for antibody binding and in the other DWEYS binds high-mobility group box-1 and blocks its interaction with RAGE. Our data highlight distinct pathways involved in nucleic acid enters monocytes in SLE, and identify a potential therapeutic to prevent nucleic acid internalization in SLE.

Identifying Reliable Diagnostic/Predictive Biomarkers for Rheumatoid Arthritis

Introduction and objective:

Elevated C-reactive protein is usually a good indicator of rheumatoid arthritis (RA); however, there are limitations that compromise its specificity and therefore there is an urgent need to identify more reliable diagnostic biomarkers to detect early stages of RA. In addition, identifying the correct therapeutic biomarker for the treatment of RA using methotrexate (MTX) would greatly increase the benefits experienced by the patients.

Materials and methods:

Primary normal synoviocytes human fibroblast-like synoviocytes (HFLS) and its phenotype rheumatic HFLS-RA cells were chosen for this study. The HFLS-RA–untreated and MTX-treated cells were subjected to microarray analysis.

Results:

Microarray data identified 74 differentially expressed genes. These genes were mapped against an RA inflammatory pathway, shortlisting 10 candidate genes. Gene expression profiling of the 10 genes were studied. Fold change (FC) was calculated to determine the differential expression of the samples.

Discussion:

The transcription profiles of the 10 candidate genes were highly induced in HFLS-RA cells compared with HFLS cells. However, on treating the HFLS-RA cells with MTX, the transcription profiles of these genes were highly downregulated. The most significant expression FC difference between HFLS and HFLS-RA (treated and untreated) was observed with HSPA6, MMP1, MMP13, and TNFSF10 genes.

Conclusions:

The data from this study suggest the use of HSPA6, MMP1, MMP13, and TNFSF10 gene expression profiles as potential diagnostic biomarkers. In addition, these gene profiles can help in predicting the therapeutic efficacy of MTX.

Safety, Biodistribution, and Efficacy of an AAV-5 Vector Encoding Human Interferon-Beta (ART-I02) Delivered via Intra-Articular Injection in Rhesus Monkeys with Collagen-Induced Arthritis

Preclinical studies to assess biodistribution, safety, and initial efficacy of ART-I02, an adeno-associated type 5 (rAAV5) vector expressing human interferon β (hIFN-β), were performed in a total of 24 rhesus monkeys with collagen-induced arthritis. All monkeys were naïve or showed limited neutralizing antibody (Nab) titers to AAV5 at the start of the study. Animals were injected with a single intra-articular dose of ART-I02 or placebo, consisting of 3.2×10(13) vg (Dose A=maximum feasible dose), 4.58×10(12) vg (Dose B), or placebo in the first affected finger joint, the ipsilateral knee, and ankle joint at the same time point. Animals were monitored for clinical parameters and well-being with a maximum of 4 weeks, with the option that the severity of arthritis could necessitate an earlier time point of sacrifice. No adverse events were noted after injection of ART-I02. No abnormalities were observed after histological evaluation of all organs. At both dose levels, immunohistochemical staining indicated expression of hIFN-β. In animals injected with Dose A, we observed stabilization or a reduction in swelling in the finger joint in which vector was administered. The highest copy numbers of vector DNA were detected in synovial tissue of the injected joint and the draining lymph node of the injected knee. High titers of Nab to rAAV5 were observed at the end of the study. Five monkeys developed an rAAV5-specific T-cell response. Two monkeys developed Nab to hIFN-β. In conclusion, intra-articular injection of ART-I02 was well-tolerated and did not induce adverse events. After administration of Dose A of ART-I02, we observed a beneficial effect on joint swelling, substantiated by decreased histological inflammation and bone erosion scores. A GMP vector for clinical application has been manufactured and is currently being tested in GLP rodent studies, with the aim to move forward to a clinical trial.

Optimization of Fermentation Conditions for Recombinant Human Interferon Beta Production by Escherichia coli Using the Response Surface Methodology

Background:

The periplasmic overexpression of recombinant human interferon beta (rhIFN-β)-1b using a synthetic gene in Escherichia coli BL21 (DE3) was optimized in shake flasks using Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD).

Objectives:

This study aimed to predict and develop the optimal fermentation conditions for periplasmic expression of rhIFN-β-1b in shake flasks whilst keeping the acetate excretion as the lowest amount and exploit the best results condition for rhIFN-β in a bench top bioreactor.

Materials and Methods:

The process variables studied were the concentration of glucose as carbon source, cell density prior the induction (OD _{600 nm}) and induction temperature. Ultimately, a three-factor three-level BBD was employed during the optimization process. The rhIFN-β production and the acetate excretion served as the evaluated responses.

Results:

The proposed optimum fermentation condition consisted of 7.81 g L^-1 glucose, OD _{600 nm} prior induction 1.66 and induction temperature of 30.27°C. The model prediction of 0.267 g L^-1 of rhIFN-β and 0.961 g L^-1 of acetate at the optimum conditions was verified experimentally as 0.255 g L^-1 and 0.981 g L^-1 of acetate. This agreement between the predicted and observed values confirmed the precision of the applied method to predict the optimum conditions.

Conclusions:

It can be concluded that the RSM is an effective method for the optimization of recombinant protein expression using synthetic genes in E. coli.

Exogenous IFN-beta regulates the RANKL-c-Fos-IFN-beta signaling pathway in the collagen antibody-induced arthritis model

Background

Although a variety of drugs have been used to treat the symptoms of rheumatoid arthritis (RA), none of them are able to cure the disease. Interferon β (IFN-β) has pleiotropic effects on RA, but whether it can be used to treat RA remains globally controversial. Thus, in this study we tested the effects of IFN-β on RA patients and on collagen antibody-induced arthritis (CAIA) model mice.

Methods

The cytokine and auto-antibody expression profiles in the serum and synovial fluid (SF) from RA patients were assessed using enzyme-linked immunosorbent assay (ELISA) and compared with the results from osteoarthritis (OA) patients. Exogenous IFN-β was administered to RA patients and CAIA model mice, and the therapeutic effects were evaluated. Endogenous IFN-β expression in the joint bones of CAIA model mice was evaluated by quantitative real-time PCR (qRT-PCR). The effects of exogenous IFN-β on CAIA model mice were assessed using a clinical scoring system, hematoxylin eosin and safranin-O with fast green counterstain histology, molybdenum target X-ray, and tartrate-resistant acid phosphatase (TRAP) staining. The RANKL-RANK signaling pathway was analyzed using qRT-PCR. The RAW 264.7 cell line was differentiated into osteoclasts with RANKL stimulation and then treated with exogenous IFN-β.

Results

The expression of inflammatory cytokines (IFN-γ, IL-17, MMP-3, and RANKL) and auto-antibodies (CII antibodies, RF-IgM, and anti-CCP/GPI) were significantly higher in RA compared with OA patients. After IFN-β intervention, some clinical symptoms in RA patients were partially alleviated, and the expression of IFN-γ, IL-17, MMP-3, and OPG) returned to normal levels. In the CAIA model, the expression of endogenous IFN-β in the joint bones was decreased. After IFN-β administration, the arthritis scores were decreased; synovial inflammation, cartilage, and bone destruction were clearly attenuated; and the expression of c-Fos and NFATc1 were reduced, while RANKL and TRAF6 expression was unchanged. In addition, exogenous IFN-β directly inhibited RANKL-induced osteoclastogenesis.

Conclusions

Exogenous IFN-β administration immunomodulates CAIA, may reduce joint inflammation and, perhaps more importantly, bone destruction by inhibiting the RANKL-c-Fos signaling pathway. Exogenous IFN-β intervention should be selectively used on RA patients because it may only be useful for RA patients with low endogenous IFN-β expression.

Cannabinoid WIN-55,212-2 mesylate inhibits interleukin-1β induced matrix metalloproteinase and tissue inhibitor of matrix metalloproteinase expression in human chondrocytes

OBJECTIVE

Interleukin-1β (IL-1β) is involved in the up-regulation of matrix metalloproteinases (MMPs) leading to cartilage degradation. Cannabinoids are anti-inflammatory and reduce joint damage in animal models of arthritis. This study aimed to determine a mechanism whereby the synthetic cannabinoid WIN-55,212-2 mesylate (WIN-55) may inhibit cartilage degradation.

METHODS

Effects of WIN-55 were studied on IL-1β stimulated production of MMP-3 and -13 and their inhibitors TIMP-1 and -2 in human chondrocytes. Chondrocytes were obtained from articular cartilage of patients undergoing total knee replacement. Chondrocytes were grown in monolayer and 3D alginate bead cultures. Real-time polymerase chain reaction (PCR) was used to determine the gene expression of MMP-3, -13, TIMP-1 and -2 and Enzyme Linked Immunosorbent Assay (ELISA) to measure the amount of MMP-3 and MMP-13 protein released into media. Immunocytochemistry was used to investigate the expression of cannabinoid receptors in chondrocyte cultures.

RESULTS

Treatment with WIN-55 alone or in combination with IL-1β, decreased or abolished MMP-3, -13, TIMP-1 and -2 gene expression in human chondrocyte monolayer and alginate bead cultures in both a concentration and time dependent manner. WIN-55 treatment alone, and in combination with IL-1β, reduced MMP-3 and -13 protein production by chondrocytes cultured in alginate beads. Immunocytochemistry demonstrated the expression of cannabinoid receptors in chondrocyte cultures.

CONCLUSION

Cannabinoid WIN-55 can reduce both basal and IL-1β stimulated gene and protein expression of MMP-3 and -13. However WIN-55 also decreased basal levels of TIMP-1 and -2 mRNA. These actions of WIN-55 suggest a mechanism by which cannabinoids may act to prevent cartilage breakdown in arthritis.

The physiologic increase in expression of some type I IFN-inducible genes during pregnancy is not associated with improved disease activity in pregnant patients with rheumatoid arthritis

During pregnancy, most patients with rheumatoid arthritis (RA) experience a spontaneous improvement in their condition. Since type I interferons (IFN) have immunomodulatory properties, we investigated whether type I IFN-inducible genes are upregulated in pregnant patients with RA. Peripheral blood mononuclear cells were evaluated using quantitative real-time polymerase chain reaction for type I IFN-inducible genes (IFI 35, IFI44, IFI44L, IFIT3, OAS1, and Siglec1) in patients with RA and healthy women during and after pregnancy as well as in nonpregnant controls. IFN-alpha and IFN-beta levels in sera of patients and healthy donors were analyzed by enzyme linked immunosorbent assay. It was found that healthy women did not show a change of gene expression levels from the second trimester until postpartum, yet some type I IFN-inducible genes were significantly upregulated in pregnant and postpartum women compared with nonpregnant individuals. In patients with RA, a pronounced upregulation of IFI35 and IFI44 at the second trimester and a peak expression of Siglec1 at the third trimester were observed. Pregnancy levels of IFI35 and IFI44 in patients with RA were higher than those of nonpregnant patients with RA. No significant association of gene expression levels with disease activity was found. In the sera of patients and healthy women, IFN-beta was undetectable and IFN-alpha levels remained stable throughout pregnancy and postpartum. Thus, pregnancy can give rise to an increased expression of type I IFN-inducible genes, reflecting an upregulation of the innate immune system. However, an association of type I IFN-inducible genes with pregnancy induced disease amelioration seems unlikely.

Replacements of rare herbs and simplifications of traditional chinese medicine formulae based on attribute similarities and pathway enrichment analysis

A Traditional Chinese Medicine (TCM) formula is a collection of several herbs. TCM formulae have been used to treat various diseases for several thousand years. However, wide usage of TCM formulae has results in rapid decline of some rare herbs. So it is urgent to find common available replacements for those rare herbs with the similar effects. In addition, a formula can be simplified by reducing herbs with unchanged effects. Based on this consideration, we propose a method, called "formula pair," to replace the rare herbs and simplify TCM formulae. We show its reasonableness from a perspective of pathway enrichment analysis. Both the replacements of rare herbs and simplifications of formulae provide new approaches for a new formula discovery. We demonstrate our approach by replacing a rare herb "Forsythia suspensa" in the formula "the seventh of Sang Ju Yin plus/minus herbs (SSJY)" with a common herb "Thunberg Fritillary Bulb" and simplifying two formulae, "the fifth of Du Huo Ji Sheng Tang plus/minus herbs (FDHJST)" and "Fang Feng Tang" (FFT) to a new formula "Fang Feng Du Huo Tang" (FFDHT).

Abnormal networks of immune response-related molecules in bone marrow cells from patients with rheumatoid arthritis as revealed by DNA microarray analysis

INTRODUCTION

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic synovitis that progresses to destruction of cartilage and bone. Bone marrow (BM) cells have been shown to contribute to this pathogenesis. In this study, we compared differentially expressed molecules in BM cells from RA and osteoarthritis (OA) patients and analyzed abnormal regulatory networks to identify the role of BM cells in RA.

METHODS

Gene expression profiles (GEPs) in BM-derived mononuclear cells from 9 RA and 10 OA patients were obtained by DNA microarray. Up- and down-regulated genes were identified by comparing the GEPs from the two patient groups. Bioinformatics was performed by Expression Analysis Systemic Explorer (EASE) 2.0 based on gene ontology, followed by network pathway analysis with Ingenuity Pathways Analysis (IPA) 7.5.

RESULTS

The BM mononuclear cells showed 764 up-regulated and 1,910 down-regulated genes in RA patients relative to the OA group. EASE revealed that the gene category response to external stimulus, which included the gene category immune response, was overrepresented by the up-regulated genes. So too were the gene categories signal transduction and phosphate metabolism. Down-regulated genes were dominantly classified in three gene categories: cell proliferation, which included mitotic cell cycle, DNA replication and chromosome cycle, and DNA metabolism. Most genes in these categories overlapped with each other. IPA analysis showed that the up-regulated genes in immune response were highly relevant to the antigen presentation pathway and to interferon signaling. The major histocompatibility complex (MHC) class I molecules, human leukocyte antigen (HLA)-E, HLA-F, and HLA-G, tapasin (TAP) and TAP binding protein, both of which are involved in peptide antigen binding and presentation via MHC class I molecules, are depicted in the immune response molecule networks. Interferon gamma and interleukin 8 were overexpressed and found to play central roles in these networks.

CONCLUSIONS

Abnormal regulatory networks in the immune response and cell cycle categories were identified in BM mononuclear cells from RA patients, indicating that the BM is pathologically involved in RA.

Type I interferon in organ-targeted autoimmune and inflammatory diseases

A significant role for IFNα in the pathogenesis of systemic lupus erythematosus is well supported, and clinical trials of anti-IFNα monoclonal antibodies are in progress in this disease. In other autoimmune diseases characterized by substantial inflammation and tissue destruction, the role of type I interferons is less clear. Gene expression analysis of peripheral blood cells from patients with rheumatoid arthritis and multiple sclerosis demonstrate an interferon signature similar to but less intense than that seen in patients with lupus. In both of those diseases, presence of the interferon signature has been associated with more significant clinical manifestations. At the same time, evidence supports an anti-inflammatory and beneficial role of IFNβ locally in the joints of patients with rheumatoid arthritis and in murine arthritis models, and many patients with multiple sclerosis show a clinical response to recombinant IFNβ. As can also be proposed for type I diabetes mellitus, type I interferon appears to contribute to the development of autoimmunity and disease progression in multiple autoimmune diseases, while maintaining some capacity to control established disease - particularly at local sites of inflammation. Recent studies in both rheumatoid arthritis and multiple sclerosis suggest that quantification of type I interferon activity or target gene expression might be informative in predicting responses to distinct classes of therapeutic agents.

Overview of the biology of type I interferons

Type I interferons are pleiotropic cytokines with antiviral, antitumor and immunoregulatory functions. An aspect of their complex biology is the paradox that, depending on context, type I interferons can be anti-inflammatory and tissue protective or can be proinflammatory and promote autoimmunity. Along these lines, the activation of type I interferon pathways is effective in suppressing disease activity in patients with multiple sclerosis and in animal models of arthritis and colitis, while there is an expectation that blockade of the same pathways will be beneficial in the treatment of patients with systemic lupus erythematosus.

Association of the response to tumor necrosis factor antagonists with plasma type I interferon activity and interferon-beta/alpha ratios in rheumatoid arthritis patients: a post hoc analysis of a predominantly Hispanic cohort

OBJECTIVE

Despite the substantial clinical efficacy of tumor necrosis factor alpha (TNFalpha) antagonist therapy in patients with rheumatoid arthritis (RA), some patients respond poorly to such agents. Since an interferon (IFN) signature is variably expressed among RA patients, we investigated whether plasma type I IFN activity might predict the response to TNF antagonist therapy.

METHODS

RA patients (n = 35), the majority of whom were Hispanic, from a single center were evaluated before and after initiation of TNF antagonist therapy. As controls, 12 RA patients from the same center who were not treated with a TNF antagonist were studied. Plasma type I IFN activity was measured using a reporter cell assay, and disease status was assessed using the Disease Activity Score in 28 joints (DAS28). Levels of interleukin-1 receptor antagonist (IL-1Ra) were determined in baseline plasma samples using a commercial enzyme-linked immunosorbent assay. The clinical response was classified according to the European League Against Rheumatism criteria for improvement in RA.

RESULTS

Plasma type I IFN activity at baseline was significantly associated with clinical response (odds ratio 1.36 [95% confidence interval 1.05-1.76], P = 0.020), with high baseline IFN activity associated with a good response. Changes in DAS28 scores were greater among patients with a baseline plasma IFNbeta/alpha ratio >0.8 (indicating elevated plasma IFNbeta levels). Consistent with the capacity of IFNbeta to induce IL-1Ra, elevated baseline IL-1Ra levels were associated with better therapeutic outcomes (odds ratio 1.82 [95% confidence interval 1.1-3.29], P = 0.027).

CONCLUSION

The plasma type I IFN activity, the IFNbeta/alpha ratio, and the IL-1Ra level were predictive of the therapeutic response in TNF antagonist-treated RA patients, indicating that these parameters might define clinically meaningful subgroups of RA patients with distinct responses to therapeutic agents.

Rheumatoid arthritis synovium contains two subsets of CD83-DC-LAMP- dendritic cells with distinct cytokine profiles

Dendritic cells (DCs) have been proposed to play a pivotal role in the initiation and perpetuation of rheumatoid arthritis (RA) by presentation of arthritogenic antigens to T cells. We investigated the in vivo characteristics of two major DC subsets, myeloid DCs (mDCs) and plasmacytoid DCs (pDCs), in RA synovial tissue (ST) by measuring their frequency, phenotype, distribution, and cytokine expression. ST was obtained by arthroscopy from 20 RA, 8 psoriatic arthritis, and 10 inflammatory osteoarthritis patients. Levels of CD1c(+) mDCs and CD304(+) pDCs present in ST were quantified by digital image analysis, and their distribution was assessed by double immunolabeling with antibodies against CD3 and CD8. The maturation status and cytokine profile of mDCs and pDCs were quantified by double-immunofluorescence microscopy. In RA patients, the number of CD304(+) pDCs exceeded that of CD1c(+) mDCs, with the majority of infiltrating DCs being CD83(-) or DC-LAMP(-). Synovial pDC numbers were especially increased in RA patients who were positive for rheumatoid factor and anti-citrullinated peptide antibody. mDCs and pDCs were localized adjacent to lymphocyte aggregates. In ST from RA patients, both mDCs and pDCs expressed interleukin (IL)-15. IL-18 and interferon (IFN)-alpha/beta were mainly expressed by pDCs whereas IL-12p70 and IL-23p19 expression was predominant in mDCs. These data characterize the phenotypes of mDCs and pDCs in inflammatory synovitis and define for the first time the cytokine expression profile of these DC subsets.

The ubiquitin-mediated degradation of Jak1 modulates osteoclastogenesis by limiting interferon-beta-induced inhibitory signaling

Interferons (IFNs) have been shown to negatively regulate osteoclastogenesis. In a proteomic study to assess protein expression during osteoclastogenesis, we discovered that the expression level of Jak1 was significantly decreased during the early stage of osteoclast differentiation from mouse bone marrow macrophages (BMMs) upon stimulation with receptor activator of nuclear factor kappaB ligand (RANKL). RANKL induced Jak1 ubiquitination, and a proteasome inhibitor MG132 efficiently blocked the RANKL-induced degradation of Jak1. The expression level of Jak1 correlated with the susceptibility of osteoclast precursors to the negative regulatory effects of IFN-beta on osteoclastogenesis, since preosteoclasts (pOCs) in which Jak1 expression is significantly reduced could proceed with osteoclastogenesis in the presence of IFN-beta. Forced down-regulation of Jak1 by small interfering RNA (siRNA) resulted in the efficient osteoclast differentiation of BMMs in the presence of inhibitory IFN-beta, while overexpression of Jak1 in pOCs elicited IFN-beta-dependent inhibition of osteoclastogenesis. Furthermore, we found that the IFN-beta-induced inhibition of osteoclastogenesis required STAT3 downstream of Jak1. These data suggest that the regulation of Jak1 expression during osteoclast differentiation might serve as an intrinsic mechanism that determines osteoclast lineage commitment by modulating the negative regulation by IFN-beta.

Inhibition of interleukin 1-induced matrix metalloproteinase 13 expression in human chondrocytes by interferon gamma

BACKGROUND

Despite well-documented immunomodulation by interferon gamma (IFNgamma), its role and mechanism of regulation of matrix metalloproteinase 13 (MMP13) gene expression in human chondrocytes is unknown.

OBJECTIVE

To investigate the ability and mechanism of IFNgamma to suppress interleukin 1 (IL1)-induced MMP13 expression in articular chondrocytes.

METHODS

Human chondrocytes were treated with IFNgamma or IL1beta alone or in combination. MMP13 mRNA was analysed by semiquantitative reverse transcriptase-PCR. MMP13 protein, phospho-signal transducer and activator of transcription 1 (STAT1) and p44/42 mitogen-activated protein kinase levels were measured by western blotting. MMP13 promoter luciferase, cytomegalovirus cyclic AMP response element-binding protein (CBP)/p300 plasmids and STAT1 small interfering RNA (siRNA) were transfected by the calcium phosphate method. IFNgamma receptor was also neutralised. Activator protein (AP) 1 activity was monitored by the TransAM transcription factor kit. STAT1-CBP/p300 interaction was studied by immunoprecipitation.

RESULTS

IFNgamma potently suppressed IL1-induced expression of MMP13 and promoter activity. Blockade with neutralising IFNgamma R1 antibody revealed that MMP13 inhibition by IFNgamma is mediated by the IFN receptor. IFNgamma-stimulated activation of STAT1 was directly correlated with MMP13 suppression. Knockdown of the STAT1 gene by specific siRNA or its inhibition with fludarabine partially restored the IL1beta induction of MMP13 expression and promoter activity. IFNgamma did not alter AP1 binding ability but promoted physical interaction of STAT1 and CBP/p300 coactivator. p300 overexpression reversed IFNgamma inhibition of endogenous MMP13 mRNA expression and exogenous MMP13 promoter activity.

CONCLUSION

IFNgamma, through its receptor, activates STAT1, which binds with CBP/p300 coactivator, sequesters it from the cell system, and thus inhibits transcriptional induction of the MMP13 gene in chondrocytes. IFNgamma and its signalling pathways could be targeted therapeutically for diminishing IL1-induced cartilage degradation by MMP13 in patients with arthritis.

Intraarticular interferon-beta gene therapy ameliorates adjuvant arthritis in rats

Interferon (IFN)-beta has significant immunomodulatory properties and has received much interest as a potentially therapeutic agent for rheumatoid arthritis (RA). Systemic IFN-beta treatment of patients with RA was not effective, probably because of pharmacokinetic issues. Therefore, we studied the effect of local IFN-beta production by adenovirus-mediated gene transfer to the ankle joints of arthritic rats. Adjuvant arthritis (AA) in rats was used as a model to study intraarticular gene therapy with an adenoviral vector encoding the rat IFN-beta gene (Ad.IFN-beta). The effect on paw swelling was measured by water displacement plethysmometry. Synovial tissue of the hind paws was examined by immunohistochemistry. Bone destruction was analyzed on the basis of radiographs. In addition, quantitative real-time polymerase chain reaction was used to assess IFN-beta expression. Levels of IFN-beta mRNA and protein peaked 2 days after intraarticular injection and declined thereafter. Local delivery of Ad.IFN-beta after the onset of disease reduced paw swelling significantly. This was accompanied by a reduction in synovial inflammation. The clinical effects in rat AA lasted up to 9 days. Strikingly, Ad.IFN-beta treatment protected bone from erosion, reduced levels of c-Cbl and Cbl-b (both signaling molecules essential for osteoclast activity), and reduced the matrix metalloproteinase-3:tissue inhibitor of metalloproteinase-1 ratio in the joint. Immunohistochemical analysis of the synovial tissue revealed a clear shift toward a more antiinflammatory cytokine profile. Local overexpression of IFN-beta inhibits arthritis progression and protects against bone destruction in rat AA. These findings validate IFN-beta as a therapeutic molecule for intraarticular gene therapy of arthritis.

Stromal cells and osteoclasts are responsible for exacerbated collagen-induced arthritis in interferon-beta-deficient mice

OBJECTIVE

Clinical trials using interferon-beta (IFNbeta) in the treatment of rheumatoid arthritis have shown conflicting results. We undertook this study to understand the mechanisms of IFNbeta in arthritis at a physiologic level.

METHODS

Collagen-induced arthritis (CIA) was induced in IFNbeta-deficient and control mice. The role of IFNbeta was investigated in both the priming and effector phases of the disease. The effect of IFNbeta deficiency on synovial cells, macrophages, and fibroblasts from preimmunized mice was analyzed by flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay. Differences in osteoclast maturation were determined in situ by histology of arthritic and naive paws and by in vitro maturation studies of naive bone marrow cells. The importance of IFNbeta-producing fibroblasts was determined by transferring fibroblasts into mice at the time of CIA immunization.

RESULTS

Mice lacking IFNbeta had a prolonged disease with a higher incidence compared with control mice. IFNbeta deficiency was found to influence the effector phase, but not the priming phase, of arthritis. Compared with control mice, IFNbeta-deficient mice had greater infiltration of CD11b+ cells and greater production of tumor necrosis factor alpha in vivo, and their macrophages and fibroblasts were both more activated in vitro. Moreover, IFNbeta-deficient mice generated a greater number of osteoclasts in vitro, and mice immunized to induce arthritis, but not naive mice, had a greater number of osteoclasts in vivo compared with control mice. Importantly, IFNbeta-competent fibroblasts were able to ameliorate arthritis in IFNbeta-deficient recipients.

CONCLUSION

Our data indicate that IFNbeta is involved in regulating the activation state of osteoclasts and stromal cells, including macrophages and fibroblasts, but that it has little effect on T cells.

Interferon-gamma and interferon-beta affect endogenous catecholamines in human peripheral blood mononuclear cells: implications for multiple sclerosis

Interferon (IFN)-gamma plays a pivotal role in the pathogenesis of multiple sclerosis (MS), while IFN-beta may be able to modify the clinical course of the disease, eventually also by counterbalancing IFN-gamma-mediated effects. Catecholamines (CA) exert important effects on the immune response, both as transmitters between the nervous and the immune system, as well as autocrine/paracrine mediators in immune cells, and several lines of evidence support their involvement in MS. In particular, dysregulated production of CA seems to occur in peripheral blood mononuclear cells (PBMCs) of MS patients. We assessed the effects of IFN-beta and IFN-gamma on endogenous CA in PBMCs. In cultured PBMCs stimulated with phytohaemagglutinin (PHA), IFN-beta increased CA production and induced CA release in the culture medium, while IFN-gamma decreased both CA production and the expression of mRNA for the CA-synthesizing enzyme tyrosine hydroxylase. Coincubation with both IFNs prevented the inhibitory effect of IFN-gamma, as well as the stimulatory effect of IFN-beta. IFNs are the first physiological compounds shown to affect endogenous CA in PBMCs: in view of the role of CA-dependent mechanisms in the immune response, these findings may help to better understand the mechanisms of action of IFN-beta as an immunomodulatory drug in MS.

The production of IL-1 receptor antagonist in IFN-beta-stimulated human monocytes depends on the activation of phosphatidylinositol 3-kinase but not of STAT1

IFN-beta induces the production of secreted IL-1R antagonist (sIL-1Ra) without triggering synthesis of the agonist IL-1beta in human monocytes. This might account for its anti-inflammatory properties. Canonically, IFN-beta signals through activation of JAK/STAT pathway, although PI3K and MAPK have also been involved. In this study, the role of PI3K, MEK1, and STAT1 in IFN-beta-induced sIL-1Ra production is investigated in freshly isolated human blood monocytes. PI3K, but not MEK1 activation is essential for sIL-1Ra production in monocytes treated with IFN-beta, as demonstrated by using the respective inhibitors of PI3K and MEK1, Ly294002 and PD98059. The use of cycloheximide and actinomycin D shows that sIL-1Ra was an immediate early gene induced by IFN-beta and that PI3K was controlling sIL-1Ra gene transcription. Although both inhibitors of PI3K and MEK1 diminished the Ser(727) phosphorylation of STAT1 induced by IFN-beta, only Ly294002 inhibited sIL-1Ra production. Furthermore, the inhibition of STAT1-Ser(727) phosphorylation by Ly294002 did not affect STAT1 translocation, suggesting that STAT1 was not involved in sIL-1Ra gene induction. This was confirmed in monocytes that were transfected with small interfering RNA specifically targeting STAT1. Indeed, monocytes in which effective STAT1 gene knockdown was achieved were fully responsive to IFN-beta in terms of sIL-1Ra production. Taken together, the present data demonstrate that the induction of sIL-1Ra transcription and production by IFN-beta in human monocytes involved PI3K, but not STAT1 activation.

Type I interferons (alpha/beta) in immunity and autoimmunity

The significance of type I interferons (IFN-alpha/beta) in biology and medicine renders research on their activities continuously relevant to our understanding of normal and abnormal (auto) immune responses. This relevance is bolstered by discoveries that unambiguously establish IFN-alpha/beta, among the multitude of cytokines, as dominant in defining qualitative and quantitative characteristics of innate and adaptive immune processes. Recent advances elucidating the biology of these key cytokines include better definition of their complex signaling pathways, determination of their importance in modifying the effects of other cytokines, the role of Toll-like receptors in their induction, their major cellular producers, and their broad and diverse impact on both cellular and humoral immune responses. Consequently, the role of IFN-alpha/beta in the pathogenesis of autoimmunity remains at the forefront of scientific inquiry and has begun to illuminate the mechanisms by which these molecules promote or inhibit systemic and organ-specific autoimmune diseases.

A multicentre, randomised, double blind, placebo controlled phase II study of subcutaneous interferon beta-1a in the treatment of patients with active rheumatoid arthritis

OBJECTIVE

To assess the efficacy of interferon beta (IFN beta) in combination with methotrexate in treatment of patients with rheumatoid arthritis.

METHODS

209 patients with active rheumatoid arthritis, who had been on methotrexate for at least six months and at a stable dose for four weeks before study entry, were randomised in double blind fashion to receive placebo (0.05 ml or 0.5 ml), IFN beta 2.2 microg (0.05 ml), or IFN beta 44 microg (0.5 ml), given subcutaneously three times weekly for 24 weeks. The primary efficacy measure was a change in radiological scores at week 24. The secondary endpoint was the proportion of patients who met the ACR 20% improvement criteria at the end of the study. Synovial biopsy specimens were obtained before and after treatment from a subset of patients. Immunohistochemistry was used to detect the presence of inflammatory cells and the results were measured by digital image analysis. Collagen crosslinks were measured in urine at different times throughout the study.

RESULTS

Analysis of radiological scores and clinical variable showed no changes in any of the groups, and there were no differences between the groups. On microscopic analysis of synovial tissue there was no significant change in the scores for infiltration by inflammatory cells after IFN beta treatment. Urinary levels of collagen crosslinks were unchanged between the treatment groups.

CONCLUSIONS

At the doses tested, treatment with IFN beta three times weekly in combination with methotrexate did not have a clinical or radiological effect in patients with rheumatoid arthritis.

Treatment with recombinant interferon-beta reduces inflammation and slows cartilage destruction in the collagen-induced arthritis model of rheumatoid arthritis

We investigated the therapeutic potential and mechanism of action of IFN-beta protein for the treatment of rheumatoid arthritis (RA). Collagen-induced arthritis was induced in DBA/1 mice. At the first clinical sign of disease, mice were given daily injections of recombinant mouse IFN-beta or saline for 7 days. Disease progression was monitored by visual clinical scoring and measurement of paw swelling. Inflammation and joint destruction were assessed histologically 8 days after the onset of arthritis. Proteoglycan depletion was determined by safranin O staining. Expression of cytokines, receptor activator of NF-kappaB ligand, and c-Fos was evaluated immunohistochemically. The IL-1-induced expression of IL-6, IL-8, and granulocyte/macrophage-colony-stimulating factor (GM-CSF) was studied by ELISA in supernatant of RA and osteoarthritis fibroblast-like synoviocytes incubated with IFN-beta. We also examined the effect of IFN-beta on NF-kappaB activity. IFN-beta, at 0.25 microg/injection and higher, significantly reduced disease severity in two experiments, each using 8-10 mice per treatment group. IFN-beta-treated animals displayed significantly less cartilage and bone destruction than controls, paralleled by a decreased number of positive cells of two gene products required for osteoclastogenesis, receptor activator of NF-kappaB ligand and c-Fos. Tumor necrosis factor alpha and IL-6 expression were significantly reduced, while IL-10 production was increased after IFN-beta treatment. IFN-beta reduced expression of IL-6, IL-8, and GM-CSF in RA and osteoarthritis fibroblast-like synoviocytes, correlating with reduced NF-kappaB activity. The data support the view that IFN-beta is a potential therapy for RA that might help to diminish both joint inflammation and destruction by cytokine modulation.

Interferon beta stimulates interleukin 1 receptor antagonist production in human articular chondrocytes and synovial fibroblasts

BACKGROUND

Interferon (IFN) beta displays anti-inflammatory and immunosuppressive activity and has been considered for the treatment of rheumatoid arthritis (RA). Information about the effects of this molecule on joint cells is scarce, however.

OBJECTIVE

To investigate the effects of IFNbeta on the production of interleukin-1 receptor antagonist (IL1Ra) in human articular chondrocytes and synovial fibroblasts.

METHODS

Chondrocytes and synovial fibroblasts were stimulated with IFNbeta alone or in combination with interleukin (IL) 1beta. IL1Ra concentrations in culture supernatants and cell lysates were determined by ELISA. Expression of mRNA encoding the secreted sIL1Ra or the intracellular icIL1Ra1 isoforms was quantified by real time reverse transcriptase-polymerase chain reaction.

RESULTS

In chondrocytes, IFNbeta alone had no effect, but dose dependently enhanced the secretion of IL1Ra induced by IL1beta. Chondrocyte cell lysates contained undetectable or low levels of IL1Ra, even after stimulation with IL1beta and IFNbeta. Consistently, IL1beta and IFNbeta induced sIL1Ra mRNA expression in chondrocytes, while expression of icIL1Ra1 was not detectable. Human articular chondrocytes thus mainly produce secreted IL1Ra. In synovial fibroblasts, IFNbeta alone dose dependently increased IL1Ra secretion. In addition, IFNbeta enhanced the stimulatory effect of IL1beta on IL1Ra production. In synovial cell lysates, IFNbeta and IL1beta also increased IL1Ra levels. Consistently, IFNbeta and IL1beta induced the expression of both sIL1Ra and icIL1Ra1 mRNA in synovial fibroblasts.

CONCLUSION

IFNbeta increases IL1Ra production in joint cells, which may be beneficial in cartilage damaging diseases such as RA or osteoarthritis.

Identification of Naf1/ABIN-1 among TNF-alpha-induced expressed genes in human synoviocytes using oligonucleotide microarrays

The cytokine tumor necrosis factor alpha (TNF-alpha) is a critical effector of the pathogenesis of rheumatoid arthritis (RA). We used oligonucleotide microarray (OM) analysis to assess TNF-alpha-modulated gene expression in cultured primary human synoviocytes in vitro. Genes identified include cytokines and inflammatory mediators, extracellular matrix and adhesion molecules, cell cycle and proliferation related proteins, transcription related proteins, and apoptotic mediators. OM identified 1185 differentially expressed genes in TNF-alpha-treated synoviocytes. The regulation of Nef-associated factor-1 (Naf1), an A20-binding, nuclear factor kappa B (NFkappaB) inhibitory protein was probed further given its putative role as an endogenous brake for the expression of some TNF-alpha-driven genes. Naf1 mRNA levels were higher in synovial biopsies from patients with active RA and seronegative arthropathy than in those from patients with osteoarthritis. These findings underscore the value of transcriptome analysis in cytokine-activated synoviocyte cultures in vitro as a means of identifying disease-associated genes in human arthritis, and implicate Naf1 as a potential modulator of TNF-alpha bioactivity in RA.

Upcoming biologic agents for the treatment of rheumatic diseases

The development of biologic agents has provided rheumatologists with a variety of new and effective treatment options. The success of early biologics, especially etanercept and infliximab for the treatment of rheumatoid arthritis, has spurred research into novel targets for the management of systemic inflammatory and autoimmune diseases. In addition, existing biologics approved for use in other diseases, such as rituximab, are now under study for the treatment of new indications. This article reviews ongoing research on the treatment of rheumatic diseases with new and existing biologic agents.