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

Helicobacter pylori disrupts gastric mucosal homeostasis by stimulating macrophages to secrete CCL3

BACKGROUND

Helicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis.

METHODS

The expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry.

RESULTS

After H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased.

CONCLUSIONS

In summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.

CCR9+CD4+ T cells are associated with disease activity in patients with rheumatoid arthritis

An increase in CD4+ T cells in the synovium is closely linked to the pathogenesis of rheumatoid arthritis (RA). We aimed to identify the possible causes of the elevated CD4+ T cell levels and to explore the factors influencing disease activity in RA. Fifty-five RA patients, including 28 with active RA (ARA), 27 with inactive RA, and 22 healthy controls, were recruited for this study. The proportion of CCR9+CD4+ T cells and the expression of chemokine receptor 9 (CCR9) on CD4+ T cells were analyzed by flow cytometry. Enzyme-linked immunosorbent assay and chemiluminescent immunoassay were used to evaluate interleukin (IL)-17A and IL-6 levels, respectively. The proportion of CCR9+CD4+ T cells and the expression of CCR9 on CD4+ T cells increased significantly in peripheral blood (PB) and synovial fluid (SF) in ARA compared to those in inactive RA. Furthermore, SF contained more CCR9+CD4+ T cells, IL-6, and IL-17A than PB in RA patients. Moreover, CD4+ T cells in the PB of patients with RA, especially ARA, expressed more CCR9 and secreted more IL-6 and IL-17A after activation. Here, we also demonstrated that both the percentage of CCR9+ cells in CD4+ T cells and the expression of CCR9 on circulating CD4+ T cells were positively correlated with erythrocyte sedimentation rate, hypersensitive C-reactive protein, rheumatoid factor, and anti-cyclic citrullinated peptide antibody. CCR9+CD4+ T cells are elevated in PB and SF, and are associated with disease activity in patients with RA.

CC Chemokine Receptor 4 (CCR4) as a Possible New Target for Therapy

Chemokines and their receptors participate in many biological processes, including the modulation of neuroimmune interactions. Approximately fifty chemokines are distinguished in humans, which are classified into four subfamilies based on the N-terminal conserved cysteine motifs: CXC, CC, C, and CX3C. Chemokines activate specific receptors localized on the surface of various immune and nervous cells. Approximately twenty chemokine receptors have been identified, and each of these receptors is a seven-transmembrane G-protein coupled receptor. Recent studies provide new evidence that CC chemokine receptor 4 (CCR4) is important in the pathogenesis of many diseases, such as diabetes, multiple sclerosis, asthma, dermatitis, and cancer. This review briefly characterizes CCR4 and its ligands (CCL17, CCL22, and CCL2), and their contributions to immunological and neoplastic diseases. The review notes a significant role of CCR4 in nociceptive transmission, especially in painful neuropathy, which accompanies many diseases. The pharmacological blockade of CCR4 seems beneficial because of its pain-relieving effects and its influence on opioid efficacy. The possibilities of using the CCL2/CCL17/CCL22/CCR4 axis as a target in new therapies for many diseases are also discussed.

Targeting chemokine receptors from the inside-out: discovery and development of small-molecule intracellular antagonists

Ever since the first biologically active chemokines were discovered in the late 1980s, these messenger proteins and their receptors have been the target for a plethora of drug discovery efforts in the pharmaceutical industry, as well as in academia. Owing to the publication of several chemokine receptor X-ray crystal structures, a highly druggable, intracellular, allosteric binding site which partially overlaps with the G protein binding site was discovered. This intriguing, new approach for chemokine receptor antagonism has captured researchers around the world, pushing the exploration of this intracellular binding site and new antagonists thereof. In this review, we have highlighted the past two decades of research on small-molecule chemokine receptor antagonists that modulate receptor function at the intracellular binding site.

Cellular and molecular diversity in Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. RA mainly affects synovial joints, with inflammation of the synovial membrane (synovitis), characterised by neo-angiogenesis, hyperplasia of lining layer, and immune cell infiltration that drive local inflammation and, if untreated, can lead to joint destruction and disability. In parallel to the well-known clinical heterogeneity, the underlying synovitis can also be significantly heterogeneous, both at cellular and molecular level, which can at least in part explain why despite the availability of highly effective treatment options, a large proportion of patients are resistant to some individual treatments. The assimilation of recent high-throughput data from analysis at the single-cell level with rigorous and high-quality clinical outcomes obtained from large randomised clinical trials support the definition of disease and treatment response endotypes. Looking ahead, the integration of histological and molecular signatures from the diseased tissue into clinical algorithms may help decision making in the management of patients with Rheumatoid Arthritis in clinical practice.

Will rheumatologists ever pick up the arthroscope again?

Conditions prompting physicians and surgeons first adapting endoscopes to peer into joints were mainly the sort of synovial conditions that would concern today's rheumatologists. Rheumatologists were among the pre-World War II pioneers developing and documenting arthroscopy. The post-War father of modern arthroscopy, Watanabe, found rheumatologists among his early students, who took back the technique to their home countries, teaching orthopedists and rheumatologists alike. Rheumatologists described and analyzed the intra-articular features of their common diseases in the '60s and '70s. A groundswell of interest from academic rheumatologists in adapting arthroscopy grew considerably in the '90s with development of "needle scopes" that could be used in an office setting. Rheumatologists helped conduct the very trials the findings of which reduced demand for their arthroscopic services by questioning the efficacy of arthroscopic debridement in osteoarthritis (OA) and also developing biological compounds that greatly reduced the call for any resective intervention in inflammatory arthropathies. The arthroscope has proven an excellent tool for viewing and sampling synovium and continues to serve this purpose at several international research centers. While cartilage is now imaged mainly by magnetic resonance imaging, some OA features - such as a high prevalence of visible calcinosis - beg further arthroscopy-directed investigation. A new generation of "needle scopes" with far superior optics awaits future investigators, should they develop interest.

Triptolide promotes the apoptosis and attenuates the inflammation of fibroblast-like synoviocytes in rheumatoid arthritis by down-regulating lncRNA ENST00000619282

Rheumatoid arthritis (RA), recognized as a common chronic autoimmune disease, is characterized by the excessive proliferation and inflammatory infiltration of fibroblast-like synoviocytes (FLS). In this study, our purpose is to elucidate the mechanisms of triptolide (TPL) in the treatment of RA by regulating the long non-coding RNA (lncRNA) ENST00000619282, which promoted apoptosis and reduced inflammatory infiltration of FLS in RA (RA-FLS). RA-FLS was treated with different concentrations of TPL at different time points. CCK-8 assay, ELISA, RT-qPCR, immunofluorescence, TUNEL assay, and the transmission electron microscopy were used to measure the changes of cell viability, apoptosis, and the release of inflammatory cytokines. Next, the involvement of ENST00000619282 in TPL-mediated protection against RA was explored. ENST00000619282 expression was significantly increased in the peripheral blood mononuclear cells (PBMCs) of RA patients. ENST0000061928 expression in RA PBMCs was positively associated with ESR, RF, CCP, and DAS28, while TPL treatment led to a downregulation of ENST00000619282. In addition, ENST00000619282 was significantly increased in RA-FLS. Furthermore, overexpression of ENST00000619282 elevated the levels of pro-apoptotic and pro-inflammatory factors, while reduced the levels of anti-apoptotic proteins and antiinflammatory factors. Besides, TPL treatment could reverse these effects by ENST00000619282 overexpression. The anti-RA potential of TPL might be achieved by downregulating ENST00000619282, thereby promoting apoptosis, and reducing the inflammatory response in RA.

Inhibition of the CXCL9-CXCR3 axis suppresses the progression of experimental apical periodontitis by blocking macrophage migration and activation

Apical periodontitis (AP) is an acute or chronic inflammatory disease caused by complex interactions between infected root canal and host immune system. It results in the induction of inflammatory mediators such as chemokines and cytokines leading to periapical tissue destruction. To understand the molecular pathogenesis of AP, we have investigated inflammatory-related genes that regulate AP development. We found here that macrophage-derived CXCL9, which acts through CXCR3, is recruited by progressed AP. The inhibition of CXCL9 by a CXCR3 antagonist reduced the lesion size in a mouse AP model with decreasing IL-1β, IL-6 and TNFα expression. The treatment of peritoneal macrophages with CXCL9 and LPS induced the transmigration and upregulation of osteoclastogenic cytokines such as IL-1β, IL-6 and matrix metalloprotease 2, a marker of activated macrophages. This suggests that the CXCL9-CXCR3 axis plays a crucial role in the development of AP, mediated by the migration and activation of macrophages for periapical tissue destruction. Our data thus show that CXCL9 regulates the functions of macrophages which contribute to AP pathogenesis, and that blocking CXCL9 suppresses AP progression. Knowledge of the principal factors involved in the progression of AP, and the identification of related inflammatory markers, may help to establish new therapeutic strategies.

Enhanced expression of coxsackievirus and adenovirus receptor in lipopolysaccharide-induced inflammatory macrophages is through TRIF-dependent innate immunity pathway

AIMS

Inflammatory macrophages have been proposed as a therapeutic target for joint disorders caused by inflammation. This study aimed to investigate the expression and regulation of coxsackievirus-adenovirus receptor (CAR) in lipopolysaccharide (LPS)-stimulated inflammatory macrophages whereby to evaluate the feasibility of virus-directed enzyme prodrug therapy (VDEPT).

MAIN METHODS

Macrophage cell lines (RAW264.7 and J774A.1) and primary macrophage cells derived from rat spleen were used to evaluate the expression of CAR protein or CAR mRNA. Specific inhibitors for TLR4 pathway were used to investigate the regulation of CAR expression. CAR expression in rat joints was documented by immunohistochemistry. Conditionally replicating adenovirus, CRAd-EGFP(PS1217L) or CRAd-NTR(PS1217H6), and non-replicating adenovirus CTL102 were used to transduce genes for enhanced green fluorescent protein (EGFP) or nitroreductase (NTR), respectively. The expression of EGFP, NTR, and the toxicity induced by CB1954 activation were evaluated.

KEY FINDINGS

The in vitro experiments revealed that CAR upregulation was mediated through the TLR4/TRIF/IRF3 pathway in LPS-stimulated inflammatory macrophage RAW264.7 and J774A.1 cells. The inflammatory RAW264.7 cells upregulated CAR expression following LPS stimulation, leading to higher infectability, increased NTR expression, and enhanced sensitization to CB1954. In animal experiments, the induction of CAR expression was observed in the CD68-expressing primary macrophages and in the CD68-expressing macrophages within joints following LPS stimulation.

SIGNIFICANCE

In conclusion, we report an enhanced CAR expression in inflammatory macrophages in vitro and in vivo through the immune response elicited by LPS. Thus, the TLR4/TRIF/IRF3 pathway of macrophages, when activated, could facilitate the therapeutic application of adenovirus-mediated VDEPT.

Targeting the rheumatoid arthritis synovial fibroblast via cyclin dependent kinase inhibition: An early phase trial

INTRODUCTION

Targeted biologic therapies demonstrate similar efficacies in rheumatoid arthritis despite distinct mechanisms of action. They also exhibit a ceiling effect, with 10% to 20% of patients achieving remission in clinical trials. None of these therapies target synovial fibroblasts, which drive and maintain synovitis. Seliciclib (R-roscovitine) is an orally available cyclin-dependent kinase inhibitor that suppresses fibroblast proliferation, and is efficacious in preclinical arthritis models. We aim to determine the toxicity and preliminary efficacy of seliciclib in combination with biologic therapies, to inform its potential as an adjunctive therapy in rheumatoid arthritis.

METHODS AND ANALYSIS

TRAFIC is a non-commercial, multi-center, rolling phase Ib/IIa trial investigating the safety, tolerability, and efficacy of seliciclib in patients with moderate to severe rheumatoid arthritis receiving biologic therapies. All participants receive seliciclib with no control arm. The primary objective of part 1 (phase Ib) is to determine the maximum tolerated dose and safety of seliciclib over 4 weeks of dosing. Part 1 uses a restricted 1-stage Bayesian continual reassessment method based on a target dose-limiting toxicity probability of 35%. Part 2 (phase IIa) assesses the potential efficacy of seliciclib, and is designed as a single arm, single stage early phase trial based on a Fleming-A'Hern design using the maximum tolerated dose recommended from part 1. The primary response outcome after 12 weeks of therapy is a composite of clinical, histological and magnetic resonance imaging scores. Secondary outcomes include adverse events, pharmacodynamic and pharmacokinetic parameters, autoantibodies, and fatigue.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the North East - Tyne & Wear South Research Ethics Committee (reference 14/NE/1075) and the Medicines and Healthcare Products Regulatory Agency (MHRA), United Kingdom. Results will be disseminated through publication in relevant peer-reviewed journals and presentation at national and international conferences.

TRIALS REGISTRATION

ISRCTN, ISRCTN36667085. Registered on September 26, 2014; http://www.isrctn.com/ISRCTN36667085Current protocol version: Protocol version 11.0 (March 21, 2019).

Emerging role of targeting macrophages in rheumatoid arthritis: Focus on polarization, metabolism and apoptosis

Macrophages maintain a dynamic balance in physiology. Various known or unknown microenvironmental signals influence the polarization, activation and death of macrophages, which creates an imbalance that leads to disease. Rheumatoid arthritis (RA) is characterized by the massive infiltration of a variety of chronic inflammatory cells in synovia. Abundant activated macrophages found in RA synovia are an early hallmark of RA, and the number of these macrophages can be decreased after effective treatment. In RA, the proportion of M1 (pro‐inflammatory macrophages) is higher than that of M2 (anti‐inflammatory macrophages). The increased pro‐inflammatory ability of macrophages is related to their excessive activation and proliferation as well as an enhanced anti‐apoptosis ability. At present, there are no clinical therapies specific to macrophages in RA. Understanding the mechanisms and functional consequences of the heterogeneity of macrophages will aid in confirming their potential role in inflammation development. This review will outline RA‐related macrophage properties (focus on polarization, metabolism and apoptosis) as well as the origin of macrophages. The molecular mechanisms that drive macrophage properties also be elucidated to identify novel therapeutic targets for RA and other autoimmune disease.

CCL3/CCR1 mediates CD14+CD16- circulating monocyte recruitment in knee osteoarthritis progression

OBJECTIVES

Monocyte-derived macrophages, as the predominant immune cell type that is increased in inflamed synovium, play a vital role during knee osteoarthritis (KOA) progression. However, the mechanisms underlying the recruitment of circulating monocytes to osteoarthritic knees remain uncertain. Based on previous data obtained from plasma, we investigated the contributions of CCL2, CCL3, CCL4 and their cognate receptors in circulating monocyte chemotaxis and KOA development.

METHODS

Using flow cytometry staining, we characterized the expression patterns of the chemokine receptors in CD14⁺CD16^- circulating monocytes from KOA patients and healthy volunteers. The expression of chemokines in synovial fluids, synovium and cartilage was investigated in KOA patients and in patients without KOA. The role of chemokines and their cognate receptors in the chemotaxis of CD14⁺CD16^- circulating monocytes was assessed using chemokine neutralizing antibodies (NA) and receptor antagonists in vitro and in vivo.

RESULTS

The majority of CD14⁺CD16^- circulating monocytes were CCR1-and CCR2-positive. CCL2, CCL3 and CCL4 were elevated in synovial fluid of KOA patients compared with that of controls. The most likely source of these chemokines is inflamed synovium and cartilage in the osteoarthritic knee. The CCL3/CCR1 and CCL2/CCR2 axes showed substantial ability to recruit CD14⁺CD16^- monocytes in transwell assays. Similar results were confirmed in a mouse model of collagenase-induced KOA (CIA) in which blocking either the CCL3/CCR1 axis or the CCL2/CCR2 axis reduced synovial hyperplasia and F4/80⁺ macrophage infiltration.

CONCLUSIONS

Our findings suggested that, analogous to the CCL2/CCR2 axis, CCL3 produced in osteoarthritic knees can chemoattract circulating monocytes to the inflamed synovium through CCR1.

Tofacitinib modulates the VZV-specific CD4+ T cell immune response in vitro in lymphocytes of patients with rheumatoid arthritis

OBJECTIVE

RA is a chronic inflammatory disease characterized by lymphocyte infiltration and release of inflammatory cytokines. Previous studies have shown that treatment with Janus kinase inhibitors, such as tofacitinib, increased the incidence rate of herpes zoster compared with conventional DMARDs. Therefore, this study aimed to investigate the effect of tofacitinib on the varicella-zoster-virus (VZV)-specific T cell immune response.

METHODS

The effect of tofacitinib on the VZV-specific T cell immune response was determined by evaluating the IFNγ production, the proliferative capacity, the VZV-induced differentiation into effector and memory T cells, the expression of activation marker CD69 and helper T cell type 1 (Th1)-characteristic chemokine receptors, such as CXCR3 and CCR5, as well as cytotoxic activity (perforin and granzyme B expression) of CD4+ T cells of patients with RA compared with healthy donors upon stimulation with VZV antigen in vitro.

RESULTS

Tofacitinib significantly reduced the IFNγ production, proliferation, activation, and CXCR3 expression of VZV-specific CD4+ T cells in a dose-dependent manner in short- and long-term lymphocyte culture. No effect on the distribution of naive, effectors or memory, or on the expression of perforin or granzyme B by VZV-specific CD4+ T cells was observed.

CONCLUSION

This study showed that tofacitinib significantly modulated the Th1 response to VZV. The poor VZV-specific cellular immune response in patients with RA may be considered in recommendations regarding appropriate vaccination strategies for enhancing the VZV-specific Th1 response.

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.

Pharmacological targets of metabolism in disease: Opportunities from macrophages

From advances in the knowledge of the immune system, it is emerging that the specialized functions displayed by macrophages during the course of an immune response are supported by specific and dynamically-connected metabolic programs. The study of immunometabolism is demonstrating that metabolic adaptations play a critical role in modulating inflammation and, conversely, inflammation deeply influences the acquisition of specific metabolic settings.This strict connection has been proven to be crucial for the execution of defined immune functional programs and it is now under investigation with respect to several human disorders, such as diabetes, sepsis, cancer, and autoimmunity. The abnormal remodelling of the metabolic pathways in macrophages is now emerging as both marker of disease and potential target of therapeutic intervention. By focusing on key pathological conditions, namely obesity and diabetes, rheumatoid arthritis, atherosclerosis and cancer, we will review the metabolic targets suitable for therapeutic intervention in macrophages. In addition, we will discuss the major obstacles and challenges related to the development of therapeutic strategies for a pharmacological targeting of macrophage's metabolism.

Chemokines in rheumatic diseases: pathogenic role and therapeutic implications

Chemokines, a family of small secreted chemotactic cytokines, and their G protein-coupled seven transmembrane spanning receptors control the migratory patterns, positioning and cellular interactions of immune cells. The levels of chemokines and their receptors are increased in the blood and within inflamed tissue of patients with rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, vasculitis or idiopathic inflammatory myopathies. Chemokine ligand-receptor interactions control the recruitment of leukocytes into tissue, which are central to the pathogenesis of these rheumatic diseases. Although the blockade of various chemokines and chemokine receptors has yielded promising results in preclinical animal models of rheumatic diseases, human clinical trials have, in general, been disappointing. However, there have been glimmers of hope from several early-phase clinical trials that suggest that sufficiently blocking the relevant chemokine pathway might in fact have clinical benefits in rheumatic diseases. Hence, the chemokine system remains a promising therapeutic target for rheumatic diseases and requires further study.

What we say and what we mean when we say redundancy and robustness of the chemokine system - how CCR5 challenges these concepts

Classically, robustness and redundancy are features that define the intricate and connected functioning of the chemokine system. Following these ideas, the lack of a particular chemokine or chemokine receptor could be compensated by the presence of other molecules with similar functions, ensuring robustness to the systems. Although these concepts are generally accepted, they represent an oversimplification of a highly complex system that works in a context-dependent manner. Based on different studies, and taking as an example the chemokine receptor CCR5 (C-C chemokine receptor type 5) and the genetic variant CCR5Δ32, which on several occasions challenge the classical concepts of redundancy and robustness of the chemokine system, we will discuss and question this general and oversimplified point of view.

Influence of the regulatory peptide galanin on cytokine expression in human monocytes

Current research into neuropeptides is bringing to light many remarkable functions of these endocrine/neurocrine/paracrine factors, such as their roles in modulating immune responses. Galanin is a neuropeptide expressed in both neural and non‐neural tissues and exerts its effects through three G protein–coupled receptors, GAL_1,2,3‐R. It has been demonstrated that galanin has modulatory effects on immune cells, including neutrophils and natural killer cells. Because monocytes express GAL₂‐R, and therefore are expected to be a target of galanin, we analyzed the effect of galanin on the expression of cytokines and chemokines by monocytes. Galanin increased the expression of IL‐1β up to 1.5‐fold, TNF‐α, IL‐10, IL‐18, and CCL3 up to twofold, and CXCL8 up to fourfold in nonactivated monocytes, but had no major effect on activated monocytes. A cross‐correlation analysis of cytokine expression profiles, irrespective of the activation status of the monocytes, revealed that galanin changed the cross‐correlation of the expression of certain cytokines. Galanin abolished several significant correlations in IFN‐γ–stimulated monocytes. For example, treatment with 10 nM galanin changed the Spearman's rank coefficient of IL‐18 and CXCL8 from 0.622 (P ≤ 0.01) to 0.126. These results further emphasize the importance of neuroregulatory peptides, such as galanin and their therapeutic potential to treat inflammatory diseases.

The many facets of macrophages in rheumatoid arthritis

Macrophages are central to the pathophysiology of rheumatoid arthritis (RA). They constitute the main source of pro-inflammatory cytokines and chemokines such as TNF and IL-1β, they activate a wide range of immune and non-immune cells, and they secrete diverse tissue degrading enzymes driving chronic pro-inflammatory, tissue destructive and pain responses in RA. However, they can also produce anti-inflammatory cytokines such as IL-10, secrete inhibitors of tissue degrading enzymes and promote immunoregulatory and protective responses, suggesting the existence of macrophages with distinct and diverse functional activities. Although the underlying basis of this phenomenon has remained obscure for years, emerging evidence has now provided insight into the mechanisms and molecular processes involved. Here, we review current knowledge on the biology of macrophages in RA, and highlight recent literature on the heterogeneity, origins and ontogeny of macrophages as part of the mononuclear phagocyte system. We also discuss their plasticity in the context of the M1/M2 paradigm, and the emerging theme of metabolic rewiring as a major mechanism for programming macrophage functions and pro-inflammatory activities. This sheds light into the many facets of macrophages in RA, their molecular regulation and their translational potential for developing novel protective and therapeutic strategies in the clinic.

Salvia mellifera-How Does It Alleviate Chronic Pain?

Black sage, Salvia mellifera, can be made into a sun tea that is used as a foot soak to treat pain patients. The monoterpenoids and diterpenoids in the preparation penetrate the skin of the feet and stop the pain chemokine cycle, which may be the basis of chronic pain. Several chronic pain patients have reported long-term improvements in their pain after treatment with the preparation.

The Role of Macrophages in the Response to TNF Inhibition in Experimental Arthritis

The reduction of synovial tissue macrophages is a reliable biomarker for clinical improvement in patients with rheumatoid arthritis (RA), and macrophages are reduced in synovial tissue shortly after initiation of TNF inhibitors. The mechanism for this initial response is unclear. These studies were performed to identify the mechanisms responsible for the initial reduction of macrophages following TNF inhibition, positing that efflux to draining lymph nodes was involved. RA synovial tissue and synovial fluid macrophages expressed CCR7, which was increased in control macrophages following incubation with TNF-α. Human TNF transgenic (hTNF-Tg) mice were treated with infliximab after development of arthritis. Ankles were harvested and examined by histology, immunohistochemistry, quantitative RT-PCR, ELISA, and flow cytometry. hTNF-Tg mice treated with infliximab demonstrated significant clinical and histologic improvement 3 d after the initiation of therapy, at which time Ly6C⁺ macrophages were significantly reduced in the ankles. However, no evidence was identified to support a role of macrophage efflux to draining lymph nodes following treatment with infliximab. In contrast, apoptosis of Ly6C⁺ macrophages in the ankles and popliteal lymph nodes, decreased migration of monocytes into the ankles, and a reduction of CCL2 were identified following the initiation of infliximab. These observations demonstrate that Ly6C⁺ macrophage apoptosis and decreased ingress of circulating monocytes into the joint are responsible for the initial reduction of macrophages following infliximab treatment in hTNF-Tg mice.

The Multifunctional Role of the Chemokine System in Arthritogenic Processes

PURPOSE OF REVIEW

The involvement of chemokines and their receptors in the genesis and perpetuation of rheumatoid arthritis, spondyloarthritis, and osteoarthritis has been clearly recognized for a long time. Nevertheless, the complexity of their contribution to these diseases is now becoming evident and this review focuses on published evidence on their mechanism of action.

RECENT FINDINGS

Studies performed on patients and in vivo models have identified a number of chemokine-mediated pathways involved in various aspects of arthritogenic processes. Chemokines promote leukocyte infiltration and activation, angiogenesis, osteoclast differentiation, and synoviocyte proliferation and activation and participate to the generation of pain by regulating the release of neurotransmitters. A number of chemokines are expressed in a timely controlled fashion in the joint during arthropathies, regulating all the aspects of inflammation as well as the equilibrium between damage and repair and between relief and pain. Thus, the targeting of specific chemokine/chemokine receptor interactions is considered a promising tool for therapeutic intervention.

CXCR3 plays a critical role for host protection against Salmonellosis

CXCR3 and its ligands are heavily associated with inflammation and have been implicated in numerous inflammatory diseases. CXCR3 plays an important role in recruiting pro-inflammatory cells, specifically neutrophils, in a model of sterile colitis whereby CXCR3^−/− mice showed an attenuated course of colitis with markedly reduced host-tissue damage in the inflamed caecum. The role of CXCR3 during infectious colitis, however, is unclear and therefore in this study, we investigated the role of CXCR3 in the regulation of the immune response during acute and chronic gastrointestinal infection, using a murine model of Salmonella enterica serovar Enteritidis. During acute infection with Salmonella, we observed significantly increased Salmonella loading in the caecum and dissemination to the spleen and liver in CXCR3^−/− mice, but not in Wt counterparts. During chronic infection, increased pathological features of inflammation were noted in the spleen and liver, with significantly increased levels of apoptosis in the liver of CXCR3^−/− mice, when compared to Wt counterparts. In addition, compromised intestinal IgA levels, CD4⁺ helper T cells and neutrophil recruitment were observed in CXCR3^−/− challenged with Salmonella, when compared to Wt counterparts. Our data suggests that CXCR3 is a key molecule in host intestinal immunity against Salmonellosis via regulating neutrophils chemotaxis.

Endothelial cells: From innocent bystanders to active participants in immune responses

The endothelium is crucially important for the delivery of oxygen and nutrients throughout the body under homeostatic conditions. However, it also contributes to pathology, including the initiation and perpetuation of inflammation. Understanding the function of endothelial cells (ECs) in inflammatory diseases and molecular mechanisms involved may lead to novel approaches to dampen inflammation and restore homeostasis. In this article, we discuss the various functions of ECs in inflammation with a focus on pathological angiogenesis, attraction of immune cells, antigen presentation, immunoregulatory properties and endothelial-to-mesenchymal transition (EndMT). We also review the current literature on approaches to target these processes in ECs to modulate immune responses and advance anti-inflammatory therapies.

Transcription factor NFAT5 promotes macrophage survival in rheumatoid arthritis

Defective apoptotic death of activated macrophages has been implicated in the pathogenesis of rheumatoid arthritis (RA). However, the molecular signatures defining apoptotic resistance of RA macrophages are not fully understood. Here, global transcriptome profiling of RA macrophages revealed that the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5) critically regulates diverse pathologic processes in synovial macrophages including the cell cycle, apoptosis, and proliferation. Transcriptomic analysis of NFAT5-deficient macrophages revealed the molecular networks defining cell survival and proliferation. Proinflammatory M1-polarizing stimuli and hypoxic conditions were responsible for enhanced NFAT5 expression in RA macrophages. An in vitro functional study demonstrated that NFAT5-deficient macrophages were more susceptible to apoptotic death. Specifically, CCL2 secretion in an NFAT5-dependent fashion bestowed apoptotic resistance to RA macrophages in vitro. Injection of recombinant CCL2 into one of the affected joints of Nfat5+/- mice increased joint destruction and macrophage infiltration, demonstrating the essential role of the NFAT5/CCL2 axis in arthritis progression in vivo. Moreover, after intra-articular injection, NFAT5-deficient macrophages were more susceptible to apoptosis and less efficient at promoting joint destruction than were NFAT5-sufficient macrophages. Thus, NFAT5 regulates macrophage survival by inducing CCL2 secretion. Our results provide evidence that NFAT5 expression in macrophages enhances chronic arthritis by conferring apoptotic resistance to activated macrophages.

CCL2/CCR2, but not CCL5/CCR5, mediates monocyte recruitment, inflammation and cartilage destruction in osteoarthritis

OBJECTIVES

While various monocyte chemokine systems are increased in expression in osteoarthritis (OA), the hierarchy of chemokines and chemokine receptors in mediating monocyte/macrophage recruitment to the OA joint remains poorly defined. Here, we investigated the relative contributions of the CCL2/CCR2 versus CCL5/CCR5 chemokine axes in OA pathogenesis.

METHODS

Ccl2-, Ccr2-, Ccl5- and Ccr5-deficient and control mice were subjected to destabilisation of medial meniscus surgery to induce OA. The pharmacological utility of blocking CCL2/CCR2 signalling in mouse OA was investigated using bindarit, a CCL2 synthesis inhibitor, and RS-504393, a CCR2 antagonist. Levels of monocyte chemoattractants in synovial tissues and fluids from patients with joint injuries without OA and those with established OA were investigated using a combination of microarray analyses, multiplexed cytokine assays and immunostains.

RESULTS

Mice lacking CCL2 or CCR2, but not CCL5 or CCR5, were protected against OA with a concomitant reduction in local monocyte/macrophage numbers in their joints. In synovial fluids from patients with OA, levels of CCR2 ligands (CCL2, CCL7 and CCL8) but not CCR5 ligands (CCL3, CCL4 and CCL5) were elevated. We found that CCR2+ cells are abundant in human OA synovium and that CCR2+ macrophages line, invade and are associated with the erosion of OA cartilage. Further, blockade of CCL2/CCR2 signalling markedly attenuated macrophage accumulation, synovitis and cartilage damage in mouse OA.

CONCLUSIONS

Our findings demonstrate that monocytes recruited via CCL2/CCR2, rather than by CCL5/CCR5, propagate inflammation and tissue damage in OA. Selective targeting of the CCL2/CCR2 system represents a promising therapeutic approach for OA.

Activation of the cholinergic anti-inflammatory system by nicotine attenuates arthritis via suppression of macrophage migration

Activation of the cholinergic anti-inflammatory pathway (CAP), which relies on the alpha-7 nicotinic acetylcholine receptor, has been reported to reduce proinflammatory cytokine levels in experimental arthritis. To gain more insight regarding the role of the CAP in the pathogenesis of arthritis, the present study focused on the modulation of macrophage infiltration. In a mouse model of collagen‑induced arthritis (CIA), nicotine and vagotomy were used to stimulate and inhibit the CAP, respectively. Subsequently, arthritic scores were measured and histopathological assessment of joint sections was conducted. Cluster of differentiation (CD)11b‑positive macrophages in the synovium were studied by immunofluorescence histochemistry. The serum levels of chemokines, including macrophage inflammatory protein (MIP)‑1α, monocyte chemoattractant protein (MCP)‑1 and MIP‑2 were evaluated by ELISA. Furthermore, the expression levels of C‑C chemokine receptor (CCR)2 and intercellular adhesion molecule (ICAM)‑1 in the synovium were evaluated by immunohistochemical staining. The results indicated that treatment with nicotine significantly attenuated the clinical and histopathological changes associated with arthritis, reduced CD11b‑positive macrophages in the synovium, and downregulated the serum expression levels of MIP‑1α and MCP‑1. Conversely, vagotomy aggravated arthritis and upregulated the expression levels of MCP‑1. However, MIP‑2 expression did not differ among the control, CIA, vagotomy and nicotine groups. In addition, the expression levels of CCR2 were reduced in the nicotine group; however, they were increased in the vagotomy group compared with in the untreated CIA group. The expression levels of ICAM‑1 in the synovium were also influenced by activation of the CAP. Taken together, the present results indicated that nicotine‑induced activation of the CAP in mice with CIA may reduce the number of macrophages in the synovium, which may serve a role in alleviating arthritis in mice.

Is there a role of synovial biopsy in drug development?

Rheumatoid arthritis (RA) is an autoimmune disease which causes significant pain, joint deformity, functional disability. The pathological hallmark of RA is inflammation of the synovium characterized by involvement of inflammatory and resident stromal cells, soluble mediators and signalling pathways leading to irreversible joint destruction. The treatment goal in RA has evolved over the last decade towards a target of disease remission that is achieved in less than a third of patients in clinical trials. The lack of therapeutic response to current treatments is suggestive of alternative drivers of RA pathogenesis that might serve as promising therapeutic targets. There are data to justify the use of synovial tissue in early drug development. Synovial tissue represents an appropriate compartment to be studied in patients with inflammatory arthritis and provides information that is distinct from peripheral blood. Modern techniques have made the procedure much more accessible and ultrasound guided biopsies represent a safe and acceptable option. Advances in analytic technologies allowing transcriptomic level of analysis can provide unique inside to target organ/tissue following the exposure to investigational medicinal product. However, there are still caveats with regard to both the choice of technique and analytical methods. Therefore the significance of synovial biopsy remains to be determined in future clinical trials. The aim of the current debate is to explore the potential for accessing and evaluating synovial tissue in early drug development, to summarize lessons we have learned from clinical trials and to discuss the challenges that have arisen so far.

Successes and failures of chemokine-pathway targeting in rheumatoid arthritis

Chemokines and chemokine receptors are involved in leukocyte recruitment and angiogenesis underlying the pathogenesis of rheumatoid arthritis (RA) and other inflammatory rheumatic diseases. Numerous chemokines, along with both conventional and atypical cell-surface chemokine receptors, are found in inflamed synovia. Preclinical studies carried out in animal models of arthritis involving agents targeting chemokines and chemokine receptors have yielded promising results. However, most human trials of treatment of RA with antibodies and synthetic compounds targeting chemokine signalling have failed to show clinical improvements. Chemokines can have overlapping actions, and their activities can be altered by chemical modification or proteolytic degradation. Effective targeting of chemokine pathways must take acount of these properties, and can also require high levels of receptor occupancy by therapeutic agents to prevent signalling. CCR1 is a promising target for chemokine-receptor blockade.

T Cell Migration in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation in joints, associated with synovial hyperplasia and with bone and cartilage destruction. Although the primacy of T cell-related events early in the disease continues to be debated, there is strong evidence that autoantigen recognition by specific T cells is crucial to the pathophysiology of rheumatoid synovitis. In addition, T cells are key components of the immune cell infiltrate detected in the joints of RA patients. Initial analysis of the cytokines released into the synovial membrane showed an imbalance, with a predominance of proinflammatory mediators, indicating a deleterious effect of Th1 T cells. There is nonetheless evidence that Th17 cells also play an important role in RA. T cells migrate from the bloodstream to the synovial tissue via their interactions with the endothelial cells that line synovial postcapillary venules. At this stage, selectins, integrins, and chemokines have a central role in blood cell invasion of synovial tissue, and therefore in the intensity of the inflammatory response. In this review, we will focus on the mechanisms involved in T cell attraction to the joint, the proteins involved in their extravasation from blood vessels, and the signaling pathways activated. Knowledge of these processes will lead to a better understanding of the mechanism by which the systemic immune response causes local joint disorders and will help to provide a molecular basis for therapeutic strategies.

CCR1 plays a critical role in modulating pain through hematopoietic and non-hematopoietic cells

Inflammation is associated with immune cells infiltrating into the inflammatory site and pain. CC chemokine receptor 1 (CCR1) mediates trafficking of leukocytes to sites of inflammation. However, the contribution of CCR1 to pain is incompletely understood. Here we report an unexpected discovery that CCR1-mediated trafficking of neutrophils and CCR1 activity on non-hematopoietic cells both modulate pain. Using a genetic approach (CCR1^−/− animals) and pharmacological inhibition of CCR1 with selective inhibitors, we show significant reductions in pain responses using the acetic acid-induced writhing and complete Freund's adjuvant-induced mechanical hyperalgesia models. Reductions in writhing correlated with reduced trafficking of myeloid cells into the peritoneal cavity. We show that CCR1 is highly expressed on circulating neutrophils and their depletion decreases acetic acid-induced writhing. However, administration of neutrophils into the peritoneal cavity did not enhance acetic acid-induced writhing in wild-type (WT) or CCR1^−/− mice. Additionally, selective knockout of CCR1 in either the hematopoietic or non-hematopoietic compartments also reduced writhing. Together these data suggest that CCR1 functions to significantly modulate pain by controlling neutrophil trafficking to the inflammatory site and having an unexpected role on non-hematopoietic cells. As inflammatory diseases are often accompanied with infiltrating immune cells at the inflammatory site and pain, CCR1 antagonism may provide a dual benefit by restricting leukocyte trafficking and reducing pain.

The Impact of Three Genospecies of Borrelia on Expression of Genes Associated with Chemokines and Their Receptors in Normal Human Dermal Fibroblasts in Vitro

An important role in pathomechanism of Lyme disease is played by the ability of spirochetes to spread within tissues, and to adhere (to platelets, erythrocytes and vascular epithelium). The principal factors regulating that process are chemokines, cytokines and adhesion particles. The aim of this study was to select genes related to the chemokines and their receptors, differentiating the type of infection in the system model, i.e. a culture of normal human diploid fibroblasts infected with three different spirochete genospecies: B. afzelii, B. garinii and B. burgdorferii sensu stricto, by comparing the infected fibroblast culture with that of the control fibroblast. The differences in the expression of genes selected on the basis of a scientific database Affymetrix were analysed by comparing transcriptomes from the four cultures of fibroblasts, using the oligonucleotide microarrays HG_U133A. In the result of infection of fibroblast cultivation with a specific Borrelia genospecies, a variable expression of the chemokines and their receptors, specific for one genospecies was observed. The fibroblast infected with B. afzelii expressed CCL4, CCL1, CCL2 and CCR10; with B. garinii - CXCL12, IL6, CCR3 and CXCR5; and with B. burgorferii sensu stricto - CCL5, CCR1, CCL3, CCL16, CXCR6, IL8, CXCR7 and CXCR3.

Emerging immunotherapies for rheumatoid arthritis

Novel treatments in development for rheumatoid arthritis target 3 broad areas: cytokines, cells, and signaling pathways. Therapies from each domain share common advantages (for example previously demonstrated efficacy, potential long-term immunomodulation, and oral administration respectively) that have stimulated research in each area but also common obstacles to their development. In this review recent progress in each area will be discussed alongside the factors that have impeded their path to clinical use.

Emerging therapies for rheumatoid arthritis

INTRODUCTION

With the introduction of biologic therapies, tremendous progress has been made in the treatment of rheumatoid arthritis (RA). However, up to 40% of patients do not respond to these treatments.

AREAS COVERED

Several new treatment strategies are discussed, with brief overview of currently performed clinical trials. The development of molecules targeting cytokines other than TNF is discussed, as well as chemokine-directed drugs. Finally, the area of small molecular inhibitors is explored.

EXPERT OPINION

Since RA is a life-long disease often evolving into disability, development of new treatment strategies remains crucial. Especially small molecules targeting JAK, Syk and PDE4 may provide novel therapeutic options.

Macrophages and angiogenesis in rheumatic diseases

Angiogenesis plays a key role in several rheumatic diseases, including rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, systemic sclerosis, systemic lupus erythematosus, and vasculitides. An imbalance between angiogenic inducers and inhibitors seems to be a critical factor in pathogenesis of these diseases. Macrophages promote angiogenesis during rheumatoid arthritis. In addition, macrophages can produce a variety of pro-angiogenic factors that have been associated with the angiogenic response occurring during other rheumatic diseases. Lastly, macrophages could be a target in the treatment of rheumatoid arthritis and other rheumatic diseases. Nevertheless, further studies are needed to better elucidate the exact role of macrophage in angiogenesis in these diseases.

Regulation of TNF-α with a focus on rheumatoid arthritis

Cytokines and chemokines represent two important groups of proteins that control the human immune system. Dysregulation of the network in which these immunomodulators function can result in uncontrolled inflammation, leading to various diseases including rheumatoid arthritis (RA), characterized by chronic inflammation and bone erosion. Potential triggers of RA include autoantibodies, cytokines and chemokines. The tight regulation of cytokine and chemokine production, and biological activity is important. Tumor necrosis factor-α (TNF-α) is abundantly present in RA patients' serum and the arthritic synovium. This review, therefore, discusses first the role and regulation of the major proinflammatory cytokine TNF-α, in particular the regulation of TNF-α production, post-translational processing and signaling of TNF-α and its receptors. Owing to the important role of TNF-α in RA, the TNF-α-producing cells and the dynamics of its expression, the direct and indirect action of this cytokine and possible biological therapy for RA are described.

Tumor necrosis factor α- and interleukin-1β-dependent induction of CCL3 expression by nucleus pulposus cells promotes macrophage migration through CCR1

OBJECTIVE

To investigate tumor necrosis factor α (TNFα) and interleukin-1β (IL-1β) regulation of CCL3 expression in nucleus pulposus (NP) cells and in macrophage migration.

METHODS

Quantitative reverse transcription-polymerase chain reaction and immunohistochemistry were used to measure CCL3 expression in NP cells. Transfections were used to determine the role of NF-κB, CCAAT/enhancer binding protein (C/EBPβ), and MAPK on cytokine-mediated CCL3 promoter activity. The effect of NP-conditioned medium on macrophage migration was measured using a Transwell system.

RESULTS

An increase in CCL3 expression and promoter activity was observed in NP cells after TNFα or IL-1β treatment. Treatment of cells with NF-κB and MAPK inhibitors abolished the effect of the cytokines on CCL3 expression. The inductive effect of p65 and C/EBPβ on the CCL3 promoter was confirmed through gain-of-function and loss-of-function studies. Notably, cotransfection with p50 completely blocked cytokine- and p65-dependent induction. In contrast, c-Rel and RelB had little effect on promoter activity. Lentiviral transduction with short hairpin RNA for p65 (shp65) and shIKKβ significantly decreased the TNFα-dependent increase in CCL3 expression. Analysis of degenerated human NP tissue samples showed that CCL3, but not CCL4, expression correlated positively with the grade of tissue degeneration. Importantly, treatment of macrophages with conditioned medium of NP cells treated with TNFα or IL-1β promoted their migration. Pretreatment of macrophages with an antagonist of CCR1, the primary receptor for CCL3 and CCL4, blocked cytokine-mediated migration.

CONCLUSION

Our findings indicate that TNFα and IL-1β modulate the expression of CCL3 in NP cells by controlling the activation of MAPK, NF-κB, and C/EBPβ signaling. The CCL3-CCR1 axis may play an important role in promoting macrophage infiltration in degenerated, herniated discs.

Cellular targeting in autoimmunity

Many biologic agents that were first approved for the treatment of malignancies are now being actively investigated and used in a variety of autoimmune diseases such as rheumatoid arthritis (RA), antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, systemic lupus erythematosus (SLE), and Sjogren's syndrome. The relatively recent advance of selective immune targeting has significantly changed the management of autoimmune disorders and in part can be attributed to the progress made in understanding effector cell function and their signaling pathways. In this review, we will discuss the recent FDA-approved biologic therapies that directly target immune cells as well as the most promising investigational drugs affecting immune cell function and signaling for the treatment of autoimmune disease.

Why is biologic therapy useful in spondyloarthritis? Knowledge from synovial immunopathologic studies of spondyloarthritis

The pathogenesis of most rheumatic diseases remains unknown. It is believed that both genetic and environmental factors play a pivotal role in the development of synovial inflammation in rheumatoid arthritis (RA), spondyloarthritis (SpA) and osteoarthritis (OA). In the last two decades, there have been many immunopathologic studies on RA, SpA and OA, and the findings revealed different types of arthritis may also present different pathologic patterns. These included higher vascularity and increased infiltration with CD163 macrophages and neutrophils, but relatively low values for lining cell (LL) hyperplasia in SpA synovium. However, the increased LL hyperplasia, as well as CD1a+ cells and the presence of intracellular citrullinated protein were more prominent in RA than in SpA synovitis. Anti-tumor necrosis factor alpha (anti-TNFα) therapy can significantly reduce synovial LL hyperplasia, vascularity and mononuclear cells infiltration in the majority of RA or SpA patients. This may explain why clinically, arthritis patients can get significant improvement after TNFα blocker treatment.

Health-related quality of life in young adult patients with rheumatoid arthritis in Iran: reliability and validity of the Persian translation of the PedsQL™ 4.0 Generic Core Scales Young Adult Version

The objective of the present study was to determine the reliability and validity of the Persian translation of the Pediatric Quality of Life Inventory (PedsQL™) 4.0 Generic Core Scales Young Adult Version in an Iranian sample of young adult patients with rheumatoid arthritis (RA). One hundred ninety-seven young adult patients with RA completed the 23-item PedsQL™ and the 36-item Short-Form Health Survey (SF-36). Disease activity based on Disease Activity Score 28 was also measured. Internal consistency and test-retest reliability, as well as construct, discriminant, and convergent validity, were tested. Confirmatory factor analysis (CFA) was used to verify the original factor structure of the PedsQL™. Also, responsiveness to change in PedsQL™ scores over time was assessed. Cronbach's alpha coefficients ranged from α = 0.82 to α = 0.91. Test-retest reproducibility was satisfactory for all scales and the total scale score. The PedsQL proved good convergent validity with the SF-36. The PedsQL distinguished well between young adult patients and healthy young adults and also RA groups with different comorbidities. The CFA did not confirm the original four-factor model, instead, analyses revealed a best-fitting five-factor model for the PedsQL™ Young Adult Version. Repeated measures analysis of variance indicated that the PedsQL scale scores for young adults increased significantly over time. The Persian translation of the PedsQL™ 4.0 Generic Core Scales Young Adult Version demonstrated good psychometric properties in young adult patients with RA and can be recommended for the use in RA research in Iran.