Cell and cytokine imbalances in rheumatoid synovitis

Quantitative proteomic analysis of synovial tissue from rats with collagen-induced arthritis

The pathway networks involved in RA pathological process were analyzed by Ingenuity pathway analysis (IPA).

Cytokine expression and cytokine-based T cell profiling in South Indian rheumatoid arthritis

Rheumatoid arthritis (RA), a chronic inflammatory disease affects up to 1% of the general population. Early diagnosis and treatment are limited by the absence of specific and reliable diagnostic/prognostic biomarkers. This study was carried out in 48 Tamil South Indian RA patients and 49 healthy controls (HC) to identify any cytokine signature(s) that could potentially serve as biomarkers. Expression profiles of Th1, Th2, Th17 and Tregs cell type-specifying cytokines and transcription factors were analyzed using real time quantitative PCR (qPCR) assay. To explore if such expression profiles mirror their steady state plasma levels, a bead-based multiplex fluorescent assay was carried out. We found that the expression of transcription factors T-bet (for Th1), GATA-3 (for Th2) and FoxP3 (for Tregs) were significantly lower in patients than in healthy controls (P<0.0001) similar to lowering of IFNγ (P=0.004) and IL-10 (P=0.04). The transcript levels of IL-12p40 and TNF-α were higher among patients as compared to HC (P<0.0001 and P=0.02, respectively). Circulating levels of assessed cytokines were in general higher in RA patients as compared to controls. These alterations in the expression of transcription factors and cytokines highlight the underlying dysregulation of T cell subsets in RA that reflects a predominantly inflammatory phenotype. Despite dissecting these cellular and molecular processes, no specific signature that could be of diagnostic and/or prognostic value was identified. Additional longitudinal follow-up studies, especially on newly diagnosed treatment-naïve patients are warranted to uncover clinically useful biomarkers of RA.

Interleukin-6 receptor blockade enhances CD39+ regulatory T cell development in rheumatoid arthritis and in experimental arthritis

OBJECTIVE

The rationale for blocking interleukin-6 (IL-6) in rheumatoid arthritis (RA) lies chiefly in the proinflammatory effect of this cytokine. Few studies have evaluated the consequences of anti-IL-6 receptor (IL-6R) antibody treatment on Treg cells. This study was undertaken to elucidate the mechanism of action of anti-IL-6R antibody treatment by studying the effects on Treg cells in an experimental arthritis model and in patients with RA.

METHODS

Mice with collagen-induced arthritis (CIA) were treated with a mouse anti-IL-6R antibody (MR16-1), and changes in Treg, Th1, and Th17 cells were assessed at key time points during the course of the disease. Peripheral blood from 15 RA patients was collected on day 0 and after 3 months of tocilizumab treatment for flow cytometry analysis of Th17 and Treg cells.

RESULTS

In MR16-1-treated mice, Th17 cell frequencies were unchanged, whereas Treg cell frequencies were increased. The Treg cell phenotype showed marked changes, with an increase in the frequency of CD39+ Treg cells in the lymph nodes and spleen. Interestingly, similar CD39+ Treg cell expansion was observed in RA patients who were tocilizumab responders at 3 months, with no change in Th17 cell frequency. Moreover, fluorescence-activated cell-sorted CD39+ Treg cells from responder RA patients were functionally able to suppress the proliferation of conventional T cells.

CONCLUSION

In both CIA and RA, the frequency of functionally suppressive CD39+ Treg cells is increased as a result of anti-IL-6R treatment, whereas Th17 cells are unaffected. The modification of Treg cell frequency and phenotype may be one of the mechanisms involved in the therapeutic effect of IL-6 blockade in RA.

Th17 Cells in Immunopathogenesis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the sequestration of various leukocyte subpopulations within both the developing pannus and synovial space. The chronic nature of this disease results in inflammation of multiple joints, with subsequent destruction of the joint cartilage and erosion of bone. Identification of T helper (Th)17 cells led to breaking the dichotomy of the Th1/Th2 axis in immunopathogenesis of autoimmune diseases such as RA, and its experimental model, collagen-induced arthritis (CIA). Th17 cells produce cytokines, including interleukin (IL)-17, IL-6, IL-21, IL-22 and tumor necrosis factor (TNF)-α, with pro-inflammatory effects, which appear to have a role in immunopathogenesis of RA. Regarding the wide ranging production of pro-inflammatory cytokines and chemokines by Th17 cells, it is expected that Th17 cell could be a potent pathogenic factor in disease immunopathophysiology. Thus the identification of effector mechanisms used by Th17 cells in induction of disease lesions may open new prospects for designing a new therapeutic strategy for treatment of RA.

Sonoporation-mediated transduction of siRNA ameliorated experimental arthritis using 3 MHz pulsed ultrasound

The goal of this feasibility study was to examine whether sonoporation assisted transduction of siRNA could be used to ameliorate arthritis locally. If successful, such approach could provide an alternative treatment for the patients that have or gradually develop adverse response to chemical drugs. Tumor necrosis factor alpha (TNF-α) produced by synovial fibroblasts has an important role in the pathology of rheumatoid arthritis, inducing inflammation and bone destruction. In this study, we injected a mixture of microbubbles and siRNA targeting TNF-α (siTNF) into the articular joints of rats, and transduced siTNF into synovial tissue by exposure to a collimated ultrasound beam, applied through a probe 6mm in diameter with an input frequency of 3.0 MHz, an output intensity of 2.0 W/cm(2) (spatial average temporary peak; SATP), a pulse duty ratio of 50%, and a duration of 1 min. Sonoporation increased skin temperature from 26.8 °C to 27.3 °C, but there were no adverse effect such as burns. The mean level of TNF-α expression in siTNF-treated knee joints was 55% of those in controls. Delivery of siTNF into the knee joints every 3 days (i.e., 7, 10, 13, and 16 days after immunization) by in vivo sonoporation significantly reduced paw swelling on days 20-23 after immunization. Radiographic scores in the siTNF group were 56% of those in the CIA group and 61% of those in the siNeg group. Histological examination showed that the number of TNF-α positive cells was significantly lower in areas of pannus invasion into the ankle joints of siTNF- than of siNeg-treated rats. These results indicate that transduction of siTNF into articular synovium using sonoporation may be an effective local therapy for arthritis.

The potential role of angiogenic factors in rheumatoid arthritis

Angiogenesis is an important phenomenon in the pathogenesis of some diseases, such as numerous types of tumors and autoimmunity, and also a number of soluble and cell-bound factors may stimulate neovascularization in inflammatory reaction processes. Here, by highlighting the significance of angiogenesis reaction in rheumatoid arthritis (RA), we will mainly focus on the role of various growth factors, cytokines, enzymes, cells, hypoxic conditions and transcription factors in the angiogenic process and we will then explain some therapeutic strategies based on blockage of angiogenesis and modification of the vascular pathology in RA.

First-year radiographic progression as a predictor of further progression in early arthritis: results of a large national French cohort

OBJECTIVE

A major goal in the treatment of recent arthritis is the prevention of joint destruction. The value of radiographic progression in the first year for predicting further radiographic progression has not been evaluated comparatively with conventional predictive factors.

METHODS

Patients with arthritis of <6 months' duration were included in the prospective French ESPOIR cohort. Radiographs were obtained and modified Sharp scores were determined by a blinded reader. The rate of progression was determined over the first year, then over the second and third years. Rapid progression was defined as a >5-point annual increase in the total Sharp score.

RESULTS

In total, 500 patients had complete data available after 3 years and were included. The total Sharp score indicated rapid progression in 123 patients (25%) in year 1 and 92 patients (18%) in years 2/3. By logistic regression, the variables independently associated with rapid progression in years 2/3 were year 1 rapid progression of the erosion and total Sharp scores, baseline erosion Sharp score, the serologic American College of Rheumatology/European League Against Rheumatism criterion, and interleukin-6 level. When these variables were combined, year 1 rapid progression made the largest contribution to predicting years 2/3 rapid progression.

CONCLUSION

First-year radiologic progression is the best independent predictor of further rapid progression in early arthritis.

Association study of human leukocyte antigen-DRB1 alleles with rheumatoid arthritis in Algerian patients

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory and multifactorial disease. Genetic predisposition seems to play an important role. The aim of this study is to explore the relationship between human leukocyte antigen (HLA)-DRB1 alleles and susceptibility, clinical and biological features of RA in an Algerian patient population.

METHODS

Using polymerase chain reaction - sequence specific primers (SSP), 134 RA patients and 132 healthy controls were genotyped for HLA-DRB1 and HLA-DRB1*04 subtypes.

RESULTS

HLA-DRB1*04 was found to have increased frequency in the RA group compared to controls (P < 0.001, OR = 3.14), and was associated with anti-citrullinated protein antibodies positivity (ACPA) (P = 0.01, OR = 2.35). In contrast, HLA-DRB1*07 was found to have a decreased frequency in patients compared to controls (P = 0.003, OR = 0.44) and significant decrease was observed in patients with the rheumatoid factor (RF) positivity subgroup (P = 0.009, OR = 0.29). HLA-DRB1*04:05 was associated with RA (P = 0.005, OR = 3.41), whereas, HLA-DRB1*04:02 showed a protective effect against RA (P = 0.003, OR = 0.20).

CONCLUSIONS

HLA-DRB1*04 was associated with increased risk for RA and ACPA positivity, while HLA-DRB1*07 was associated with reduced risk for RA and RF synthesis in Algerian patients.

Pharmacogenetics in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory arthritis leading to severe joint damage and associated with high morbidity and mortality. Disease-modifying antirheumatic drugs (DMARDs) are the mainstay of treatment in RA. DMARDs not only relieve the clinical signs and symptoms of RA but also inhibit the radiographic progression of disease. In the last decade, a new class of disease-modifying medications, the biologic agents, has been added to the existing spectrum of DMARDs in RA. However, patients' response to these agents is not uniform with considerable variability in both efficacy and toxicity. There are no reliable means of predicting an individual patient's response to a given DMARD prior to initiation of therapy. In this chapter, the current published literature on the pharmacogenetics of traditional DMARDS and the newer biologic DMARDs in RA is highlighted. Pharmacogenetics may help individualize drug therapy in patients with RA in the near future.

Inhibition of glycogen synthase kinase-3β suppresses inflammatory responses in rheumatoid arthritis fibroblast-like synoviocytes and collagen-induced arthritis

OBJECTIVES

Glycogen synthase kinase (GSK)-3β, a serine/threonine protein kinase, has been implicated as a regulator of the inflammatory response. This study was performed to evaluate the effect of selective GSK-3β inhibitors in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) and collagen-induced arthritis (CIA).

METHOD

FLS from RA patients were treated with selective GSK-3β inhibitors, including lithium chloride, 6-bromoindirubin-3'-oxime (BIO), or 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8). The effects of GSK-3β inhibition on pro-inflammatory mediators were determined by real-time PCR and ELISA. The levels of NF-κB, phosphorylated JNK, c-jun, ATF-2 and p-38 proteins were evaluated by western blot analysis. The in vivo effects of GSK-3β inhibitors were examined in mice with CIA.

RESULTS

Treatment of RA FLS with GSK-3β inhibitors induced dose-dependent reductions in gene expression and the production of pro-inflammatory mediators. The levels of NF-κB, phosphorylated JNK, c-jun, ATF-2 and p-38 were decreased following treatment with GSK-3β inhibitors. GSK-3β inhibitors treatment attenuated clinical and histological severities of CIA in mice. Infiltration of T-cells, macrophages, and tartrate-resistant acid phosphatase positive cells was decreased in joint sections of CIA mice by GSK-3β inhibitors treatment. Serum levels of IL-1β, IL-6, TNF-α and IFN-γ in CIA mice were also significantly decreased in dose-dependent manners by treatment with GSK-3β inhibitors.

CONCLUSION

Treatment with GSK-3β inhibitors suppressed inflammatory responses in RA FLS and CIA mice. These findings suggest that the inhibition of GSK-3β can be used as an effective therapeutic agent for RA.

[Interleukin-1 and the interleukin-1 receptor antagonist gene polymorphisms study in patients with rheumatoid arthritis]

OBJECTIVES

One of the most important pro-inflammatory cytokines in the pathophysiology of rheumatoid arthritis (RA) is interleukin 1 (IL-1). The purpose of this study is to evaluate the association between IL-1B (-511), IL-1 (+3953), IL-1 RN variable number of tandem repeat (VNTR) polymorphisms and the occurrence in Algerian patients with rheumatoid arthritis. We also analyze their correlations with clinical and biological phenotypes.

PATIENTS AND METHODS

One hundred and forty-seven patients with RA (119 women, 28 men) and 127 controls (70 women, 57 men) were included in the study. The analysis of two polymorphisms of IL-1B-511 and IL-1B+3953 was done by PCR-RFLP. Analysis of IL1-RN VNTR polymorphism was performed by PCR.

RESULTS

No significant difference in genotype, allelic and haplotype distribution at the three polymorphisms was observed between RA patients and controls. However, the genotype (T/T) polymorphism of IL-1B-511 is more frequent in the group of patients with positive ACPA compared with negative ACPA group (Pc=0.01, OR=4.65). Moreover, we noted that the haplotype (IL-1RN* 1/IL-1B-511T/IL-1B+3953C) was more frequent (Pc=0.03, OR=2.05) in the positive ACPA group.

CONCLUSION

The association between the allele 1 of IL-1 RN VNTR, T allele of IL1B-511 and C allele of IL1-B +3953 polymorphisms seems to predispose to the synthesis of ACPA and therefore to the occurrence of ACPA positive RA. Further studies with a larger number of patients are needed to define the real role of IL-1 in the susceptibility to or severity of RA.

Myeloid-derived suppressor cells play crucial roles in the regulation of mouse collagen-induced arthritis

Myeloid-derived suppressor cells (MDSCs) are of myeloid origin and are able to suppress T cell responses. The role of MDSCs in autoimmune diseases remains controversial, and little is known about the function of MDSCs in autoimmune arthritis. In this study, we clarify that MDSCs play crucial roles in the regulation of proinflammatory immune response in a collagen-induced arthritis (CIA) mouse model. MDSCs accumulated in the spleens of mice with CIA when arthritis severity peaked. These MDSCs inhibited the proliferation of CD4(+) T cells and their differentiation into Th17 cells in vitro. Moreover, MDSCs inhibited the production of IFN-γ, IL-2, TNF-α, and IL-6 by CD4(+) T cells in vitro, whereas they promoted the production of IL-10. Adoptive transfer of MDSCs reduced the severity of CIA in vivo, which was accompanied by a decrease in the number of CD4(+) T cells and Th17 cells in the draining lymph nodes. However, depletion of MDSCs abrogated the spontaneous improvement of CIA. In conclusion, MDSCs in CIA suppress the progression of CIA by inhibiting the proinflammatory immune response of CD4(+) T cells. These observations suggest that MDSCs play crucial roles in the regulation of autoimmune arthritis, which could be exploited in new cell-based therapies for human rheumatoid arthritis.

Wnt signaling pathway in rheumatoid arthritis, with special emphasis on the different roles in synovial inflammation and bone remodeling

Rheumatoid arthritis (RA) is a chronic symmetrical autoimmune disease of unknown etiology that affects primarily the diarthrodial joints. Characteristic features of RA pathogenesis are synovial inflammation and proliferation accompanied by cartilage erosion and bone loss. Fibroblast-like synoviocytes (FLS) display an important role in the pathogenesis of RA. Several lines of evidence show that the Wnt signaling pathway significantly participates in the RA pathogenesis. The Wnt proteins are glycoproteins that bind to the Fz receptors on the cell surface, which leads to several important biological functions, such as cell differentiation, embryonic development, limb development and joint formation. Accumulated evidence has suggested that this signaling pathway plays a key role in the FLS activation, bone resorption and joint destruction during RA development. Greater knowledge of the role of the Wnt signaling pathway in RA could improve understanding of the RA pathogenesis and the differences in RA clinical presentation and prognosis. In this review, new advances of the Wnt signaling pathway in RA pathogenesis are discussed, with special emphasis on its different roles in synovial inflammation and bone remodeling. Further studies are needed to reveal the important role of the members of the Wnt signaling pathway in the RA pathogenesis and treatment.

Therapeutic effects of extracts from Radix Toddaliae Asiaticae on collagen-induced arthritis in Balb/c mice

AIM OF THE STUDY

Radix Toddaliae Asiaticae (RTA), also named "Sanbaibang", is the dry root bark of Toddalia asiatica (L.) Lam. and has long been used as a traditional ethnic Chinese medicine for its considerable activity to alleviate pain and inflammation for patients suffering from rheumatism. It contains coumarin, alkaloids, triterpenes and volatile oils. Information regarding the anti-arthritis activity of RTA in vivo or in vitro is limited yet. In the present study, the aim is to investigate the therapeutic potential and underlying mechanisms of the ethyl alcohol extract (EtOH) and ethyl acetate fraction (EtOAc) from RTA on collagen II-induced arthritis (CIA) in mice.

MATERIALS AND METHODS

CIA animal model was performed by subcutaneous injection of type II bovine collagen (CII) on the 1st day and the 14th day of the experiment. Ethyl alcohol extract (542.8, 271.4, 135.7 mg/kg), ethyl acetate fraction (260.8, 130.4, 65.2 mg/kg) was orally administrated from the second antigen immunization for 3 weeks. Progression of edema of paws and knee joints was measured using a vernier caliper every 3 days from the 10th day after the first injection to the end of the experiment. The spleen index was measured and the knee joint changes were observed by pathological sections. ELISA was used to measure cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and interleukin-10 (IL-10) in mice serum according to the manufacturer's instructions.

RESULTS

Administration of ethyl alcohol extract and ethyl acetate fraction remarkably reduced paws and joints swelling and decreased the spleen indexes. Histopathological examination demonstrated that RTA effectively protected bone and cartilage of knee joint from erosion, lesion and deformation versus those from the control group. Besides, the concentration of cytokines like TNF-α, IL-1β, IL-6 were significantly lower than the ones from the control group respectively, while cytokine like IL-10 was remarkably higher compare with the control group.

CONCLUSION

In this present study, it is demonstrated that administration of RTA has potential and therapeutic effect on CIA. The data suggests that RTA could have a contributory ethno-pharmacological role in improved management of RA patients.

Modulation of anti-tumor necrosis factor alpha (TNF-α) antibody secretion in mice immunized with TNF-α kinoid

Tumor necrosis factor alpha (TNF-α) blockade is an effective treatment for patients with TNF-α-dependent chronic inflammatory diseases, such as rheumatoid arthritis, Crohn's disease, and psoriasis. TNF-α kinoid, a heterocomplex of human TNF-α and keyhole limpet hemocyanin (KLH) (TNF-K), is an active immunotherapy targeting TNF-α. Since the TNF-K approach is an active immunization, and patients receiving this therapy also receive immunosuppressant treatment, we evaluated the effect of some immunosuppressive drugs on the generation of anti-TNF-α antibodies produced during TNF-K treatment. BALB/c mice were injected intramuscularly with TNF-K in ISA 51 adjuvant. Mice were also injected intraperitoneally with one of the following: phosphate-buffered saline, cyclophosphamide, methylprednisolone, or methotrexate. Anti-TNF-α and anti-KLH antibody levels were assessed by enzyme-linked immunosorbent assay and the anti-TNF-α neutralizing capacity of sera by L929 bioassay. Our results showed that current treatments used in rheumatoid arthritis, such as methylprednisolone and methotrexate, do not significantly alter anti-TNF-α antibody production after TNF-K immunization. In contrast, the administration of cyclophosphamide (200 mg/kg) after immunization significantly reduced anti-TNF-α antibody titers and their neutralizing capacity.

HLA-DRB1 shared epitope genotyping using the revised classification and its association with circulating autoantibodies, acute phase reactants, cytokines and clinical indices of disease activity in a cohort of South African rheumatoid arthritis patients

Introduction

The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).

Methods

Genomic DNA was analysed using high-resolution recombinant sequence-specific oligonucleotide PCR typing of the HLA-DRB1 allele. Subtypes of the SE were classified according to the amino acids at positions 72 to 74 for the RAA sequence, and further sub-divided according to the amino acids at positions 70 and 71, which either contribute to (S2, S3P), or negate (S1, S3D) RA susceptibility. Disease activity was assessed on the basis of (1) Disease Activity Score in 28 joints using C-reactive protein (CRP), (2) rheumatoid factor (RF), (3) CRP and (4) serum amyloid A by nephelometry, anticyclic citrullinated peptide antibodies (aCCP) by an immunofluorometric procedure, and cytokines by multiplex bead array technology.

Results

Of the 143 RA patients, 81 (57%) were homozygous (SS) and 50 (35%) were heterozygous (SX) for the SE alleles with significant overexpression of S2 and S3P (respective odds ratios (ORs) 5.3 and 5.8; P < 0.0001), and 12 (8%) were classified as no SE allele (XX). Both the SS and SX groups showed a strong association with aCCP positivity (OR = 10.2 and P = 0.0010, OR = 9.2 and P = 0.0028, respectively) relative to the XX group. Clinical scores and concentrations of the other biomarkers of disease activity (RF, CRP and T helper cell type 1 (Th1), Th2, macrophage and fibroblast cytokines) were also generally higher in the SS group than in the SX and XX groups.

Conclusions

RA susceptibility alleles investigated according to revised criteria for the classification of RA were significantly increased in South African RA patients and strongly associated with aCCP in particular as well as with circulating cytokines and disease severity.