IL-29 enhances Toll-like receptor-mediated IL-6 and IL-8 production by the synovial fibroblasts from rheumatoid arthritis patients

IFN-λ: Unleashing Its Potential in Disease Therapies From Acute Inflammation Regulation to Cancer Immunotherapy

Type III interferons (IFN-λ), which include IFN-λ1 (or interleukin [IL]-29), IFN-λ2 (IL-28A), IFN-λ3 (IL-28B) and IFN-λ4, exert their effects through a unique receptor complex composed of interferon lambda receptor 1 (IFNLR1) and IL-10 receptor subunit beta (IL-10R2). Studies have highlighted their critical role in modulating immune response, particularly in the context of autoimmune diseases, viral infections and cancer. Unlike type I IFNs, which are broadly expressed, IFN-λ displays a more tissue-specific expression pattern, predominantly acting on epithelial cells and certain immune cell types, such as neutrophils and B cells. This specificity allows IFN-λ to play a pivotal role in mucosal immunity, particularly at barrier sites, such as the respiratory and gastrointestinal tracts. Emerging evidence suggests that IFN-λ has a dual role in both enhancing antiviral immunity and regulating inflammation, thus offering a promising therapeutic strategy for diseases like systemic lupus erythematosus, rheumatoid arthritis, asthma and various cancers. However, the precise mechanisms by which IFN-λ influence immune modulation and disease progression remain an area of active investigation. This review aims to provide an overview of the structure, function and signalling pathways of IFN-λ, exploring their role in immune-related diseases and discussing potential avenues for therapeutic intervention.

Patient-Specific Variability in Interleukin-6 and Myeloperoxidase Responses in Osteoarthritis: Insights from Synthetic Data and Clustering Analysis

Objectives: This study investigated the inflammatory responses of fibroblast-like synoviocytes (FLS) isolated from osteoarthritis (OA) patients, stimulated with lipopolysaccharide (LPS) and interleukin-6 (IL-6). Both experimental and synthetic data were utilised to investigate the variability in IL-6 and myeloperoxidase (MPO) production and its implications for OA pathogenesis. Methods: Synovial biopsies were obtained from OA patients undergoing joint replacement surgery. FLS were isolated, cultured, and stimulated with varying concentrations of LPS and IL-6. The production of IL-6 and MPO was measured using enzyme-linked immunosorbent assays (ELISA). Synthetic data generation techniques expanded the dataset to support comprehensive statistical analyses. Results: The patterns of inflammatory responses revealed distinct patient subgroups, highlighting individual variability. The integration of synthetic data with experimental observations validated their reliability and demonstrated dose-dependent differences in IL-6 and MPO production across patients. Conclusions: The results highlighted the importance of patient-specific factors in OA inflammation and demonstrated the utility of combining experimental and synthetic data to model individual variability. The results support the development of personalised treatment strategies in OA. Future research should include larger patient datasets and an exploration of molecular mechanisms underlying these responses.

Regulation of cytokine and chemokine expression by histone lysine methyltransferase MLL1 in rheumatoid arthritis synovial fibroblasts

Histone lysine methylation is thought to play a role in the pathogenesis of rheumatoid arthritis (RA). We previously reported aberrant expression of the gene encoding mixed-lineage leukemia 1 (MLL1), which catalyzes methylation of histone H3 lysine 4 (H3K4), in RA synovial fibroblasts (SFs). The aim of this study was to elucidate the involvement of MLL1 in the activated phenotype of RASFs. SFs were isolated from synovial tissues obtained from patients with RA or osteoarthritis (OA) during total knee joint replacement. MLL1 mRNA and protein levels were determined after stimulation with tumor necrosis factor α (TNFα). We also examined changes in trimethylation of H3K4 (H3K4me3) levels in the promoters of RA-associated genes (matrix-degrading enzymes, cytokines, and chemokines) and the mRNA levels upon small interfering RNA-mediated depletion of MLL1 in RASFs. We then determined the levels of H3K4me3 and mRNAs following treatment with the WD repeat domain 5 (WDR5)/MLL1 inhibitor MM-102. H3K4me3 levels in the gene promoters were also compared between RASFs and OASFs. After TNFα stimulation, MLL1 mRNA and protein levels were higher in RASFs than OASFs. Silencing of MLL1 significantly reduced H3K4me3 levels in the promoters of several cytokine (interleukin-6 [IL-6], IL-15) and chemokine (C-C motif chemokine ligand 2 [CCL2], CCL5, C-X-C motif chemokine ligand 9 [CXCL9], CXCL10, CXCL11, and C-X3-C motif chemokine ligand 1 [CX3CL1]) genes in RASFs. Correspondingly, the mRNA levels of these genes were significantly decreased. MM-102 significantly reduced the promoter H3K4me3 and mRNA levels of the CCL5, CXCL9, CXCL10, and CXCL11 genes in RASFs. In addition, H3K4me3 levels in the promoters of the IL-6, IL-15, CCL2, CCL5, CXCL9, CXCL10, CXCL11, and CX3CL1 genes were significantly higher in RASFs than OASFs. Our findings suggest that MLL1 regulates the expression of particular cytokines and chemokines in RASFs and is associated with the pathogenesis of RA. These results could lead to new therapies for RA.

Rheumatoid arthritis and the intestinal microbiome: probiotics as a potential therapy

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by swollen joints, discomfort, stiffness, osteoporosis, and reduced functionality. Genetics, smoking, dust inhalation, high BMI, and hormonal and gut microbiota dysbiosis are all likely causes of the onset or development of RA, but the underlying mechanism remains unknown. Compared to healthy controls, patients with RA have a significantly different composition of gut microbiota. It is well known that the human gut microbiota plays a key role in the initiation, maintenance, and operation of the host immune system. Gut microbiota dysbiosis has local or systematic adverse effects on the host immune system, resulting in host susceptibility to various diseases, including RA. Studies on the intestinal microbiota modulation and immunomodulatory properties of probiotics have been reported, in order to identify their potential possibility in prevention and disease activity control of RA. This review summarized current studies on the role and potential mechanisms of gut microbiota in the development and progression of RA, as well as the preventative and therapeutic effects and potential mechanisms of probiotics on RA. Additionally, we proposed the challenges and difficulties in the application of probiotics in RA, providing the direction for the research and application of probiotics in the prevention of RA.

Dental pulp cells cocultured with macrophages aggravate the inflammatory conditions stimulated by LPS

BACKGROUND

Pulp inflammation is complex interactions between different types of cells and cytokines. To mimic the interactions of different types of cells in inflamed dental pulp tissues, dental pulp cells (DPCs) were cocultured with different ratios of macrophages (THP-1) or LPS treatment.

METHODS

DPCs were cocultured with various ratios of THP-1, then photographed cell morphology and determined cell viability by MTT assay at preset times. Total RNA was also extracted to measure the inflammation marker-IL-6 and IL-8 expressions by RT-Q-PCR. The DPCs and THP-1 were treated with 0.01 - 1μg/ml lipopolysaccharide (LPS) and extract RNA at preset times, and detected IL-6 and IL-8 expression. DPCs were cocultured with various ratios of THP-1 with 0.1 μg/mL LPS, and detected IL-6 and IL-8 expression after 24 and 48 h. The data were analyzed by unpaired t-test or Mann-Whitney test. Differences were considered statistically significant when p < 0.05.

RESULTS

THP-1 and DPCs coculture models did not suppress the viability of DPCs and THP-1. Cocultured with various ratios of THP-1 could increase IL-6 and IL-8 expressions of DPCs (p = 0.0056 - p < 0.0001). The expressions of IL-6 and IL-8 were stronger in higher ratio groups (p = 0.0062 - p < 0.0001). LPS treatment also induced IL-6 and IL-8 expressions of DPCs and THP-1 (p = 0.0179 - p < 0.0001 and p = 0.0189 - p < 0.0001, separately). Under the presence of 0.1 μg/mL LPS, DPCs cocultured with THP-1 for 24 h also enhanced IL-6 and IL-8 expression (p = 0.0022). After cocultured with a higher ratio of THP-1 for 48 h, IL-6 and IL-8 expressions were even stronger in the presence of LPS (p = 0.0260).

CONCLUSIONS

Coculturing dental pulp cells and macrophages under LPS treatment aggravate the inflammatory process. The responses of our models were more severe than traditional inflamed dental models and better represented what happened in the real dental pulp. Utilizing our models to explore the repair and regeneration in endodontics will be future goals.

High expression of HOXC6 predicts a poor prognosis and induces proliferation and inflammation in multiple myeloma cells

BACKGROUND

Multiple myeloma (MM) is a common blood system malignance accompanied by monoclonal plasma cell hyperplasia. Homeobox C6 (HOXC6) acts as an oncogene in various cancers, but its function on MM is elusive.

OBJECTIVE

The role of HOXC6 on MM development was clarified in this study.

METHODS

HOXC6 expression and its clinical significance were determined in the peripheral blood samples collected from forty MM patients and thirty healthy adult volunteers. The overall survival was evaluated by Kaplan-Meier analysis with the log-rank test. Cell viability, proliferation and apoptosis were measured by CCK-8, EdU assay and Flow cytometry in U266 and MM.1R cells. Tumor growth was estimated by a xenograft assay. The apoptosis of tumor tissues was evaluated using TUNEL staining. The protein level in tissues was tested by immunohistochemistry.

RESULTS

The HOXC6 expression was elevated in MM and high HOXC6 level was associated with the poor overall survival of MM. Besides, the HOXC6 expression was associated with hemoglobin level and ISS stage. Furthermore, silencing HOXC6 suppressed cell proliferation, induced cell apoptosis, and restrained the secretion of inflammatory factors (TNF-α, IL-6, and IL-8) in MM cells through inactivating the NF-κB pathway. Moreover, silencing HOXC6 suppressed the tumor growth of MM, the inflammatory factors levels, and the activation of NF-κB pathway but enhanced apoptosis in vivo.

CONCLUSION

HOXC6 was elevated in MM and associated with poor survival. Knockdown of HOXC6 suppressed proliferation, inflammation and tumorigenicity of MM cells via inactivating the NF-κB pathway. HOXC6 may be a meaningful target for MM therapy.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation

OBJECTIVES

To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment.

MATERIALS AND METHODS

DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA.

RESULTS

After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05).

CONCLUSION

Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA.

CLINICAL RELEVANCE

The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

Conventional dendritic cells type 1 are strongly enriched, quiescent and relatively tolerogenic in local inflammatory arthritis

Introduction

Dendritic cells (DC) are crucial for initiating and shaping immune responses. So far, little is known about the functional specialization of human DC subsets in (local) inflammatory conditions. We profiled conventional (c)DC1, cDC2 and monocytes based on phenotype, transcriptome and function from a local inflammatory site, namely synovial fluid (SF) from patients suffering from a chronic inflammatory condition, Juvenile Idiopathic Arthritis (JIA) as well as patients with rheumatoid arthritis (RA).

Methods

Paired PB and SF samples from 32 JIA and 4 RA patients were collected for mononuclear cell isolation. Flow cytometry was done for definition of antigen presenting cell (APC) subsets. Cell sorting was done on the FACSAria II or III. RNA sequencing was done on SF APC subsets. Proliferation assays were done on co-cultures after CD3 magnetic activated cell sorting (MACS). APC Toll-like receptor (TLR) stimulation was done using Pam3CSK4, Poly(I:C), LPS, CpG-A and R848. Cytokine production was measured by Luminex.

Results

cDC1, a relatively small DC subset in blood, are strongly enriched in SF, and showed a quiescent immune signature without a clear inflammatory profile, low expression of pathogen recognition receptors (PRRs), chemokine and cytokine receptors, and poor induction of T cell proliferation and cytokine production, but selective production of IFNλ upon polyinosinic:polycytidylic acid exposure. In stark contrast, cDC2 and monocytes from the same environment, showed a pro-inflammatory transcriptional profile, high levels of (spontaneous) pro-inflammatory cytokine production, and strong induction of T cell proliferation and cytokine production, including IL-17. Although the cDC2 and monocytes showed an overlapping transcriptional core profile, there were clear differences in the transcriptional landscape and functional features, indicating that these cell types retain their lineage identity in chronic inflammatory conditions.

Discussion

Our findings suggest that at the site of inflammation, there is specific functional programming of human DCs, especially cDC2. In contrast, the enriched cDC1 remain relatively quiescent and seemingly unchanged under inflammatory conditions, pointing to a potentially more regulatory role.

Interleukin-29 Accelerates Vascular Calcification via JAK2/STAT3/BMP2 Signaling

Background Vascular calcification (VC), associated with enhanced cardiovascular morbidity and mortality, is characterized by the osteogenic transdifferentiation of vascular smooth muscle cells. Inflammation promotes VC initiation and progression. Interleukin (IL)-29, a newly discovered member of type III interferon, has recently been implicated in the pathogenesis of autoimmune diseases. Here we evaluated the role of IL-29 in the VC process and underlying inflammatory mechanisms. Methods and Results The mRNA expression of IL-29 was significantly increased and positively associated with an increase in BMP2 (bone morphogenetic protein 2) mRNA level in calcified carotid arteries from patients with coronary artery disease or chronic kidney disease. IL-29 and BMP2 proteins are colocalized in human calcified arteries. IL-29 binding to its specific receptor IL-28Rα (IL-28 receptor α) (IL-29/IL-28Rα) inhibited the proliferation of rat vascular smooth muscle cells without altering cell apoptosis or migration. IL-29 promoted the calcification of rat vascular smooth muscle cells and their osteogenic transdifferentiation in vitro as well as the rat aortic ring calcification ex vivo, induced by the calcification medium or osteogenic medium. The procalcification effect of IL-29 was reduced by pharmacological inhibition of IL-29/IL-28Rα binding as well as suppression of janus kinase 2/signal transducer and activator of transcription pathway activation, accompanied by decreased BMP2 expression in the cultured rat vascular smooth muscle cells. Conclusions These results suggest an important role of IL-29 in VC development, at least partly, via activating the janus kinase 2/signal transducer and activator of transcription 3 signaling. Inhibition of IL-29 or its specific receptor, IL-28Rα, may provide a novel strategy to reduce VC in patients with vascular diseases.

Baicalein Induces Apoptosis of Rheumatoid Arthritis Synovial Fibroblasts through Inactivation of the PI3K/Akt/mTOR Pathway

Purpose

Rheumatoid arthritis (RA) shows abnormal proliferation, apoptosis, and invasion in fibroblast-like synoviocytes (FLSs). Baicalein (BAI), extracted from Scutellaria baicalensis, is used as an anticancer drug through inducing cancer cells apoptosis. However, the mechanism of BAI in RA progression still remains unknown. Here, we demonstrated that BAI inhibited FLS proliferation and migration, whereas it enhanced apoptosis via the PI3K/Akt/mTOR pathway in vitro.

Methods

Cell viability and colony formation were analyzed by MTT and plate colony formation assays in SW982 cells, respectively. Apoptosis was detected by flow cytometry and western blotting. Epithelial-mesenchymal transition (EMT), MMP family proteins (MMP2/9), and the PI3K/Akt/mTOR pathway were detected by western blot. Cell migration was detected by scratch healing assay under BAI treatment in SW982 cells.

Results

BAI dose-dependently inhibited cell viability and colony forming in SW982 cells. BAI upregulated apoptotic proteins and downregulated EMT-related proteins, resulting in enhanced cell apoptosis and inhibited cell migration in SW982 cells. BAI also dose-dependently inhibited the phosphorylation of PI3K, Akt, and mTOR.

Conclusions

These results indicated that BAI inhibited FLSs proliferation and EMT, whereas induced cell apoptosis through blocking the PI3K/Akt/mTOR pathway, supporting clinical application for RA progression.

Alamandine, a new member of the renin-angiotensin system (RAS), attenuates collagen-induced arthritis in mice via inhibiting cytokine secretion in synovial fibroblasts

Alamandine is a novel component of the renin-angiotensin system (RAS) as well as an important biologically active peptide. It has predominantly been studied in cardiovascular context. However, its role in rheumatoid arthritis (RA) remains unknown. Here we illustrated its effects on inflammatory cytokines production by synovial fibroblasts from RA and pathological changes in collagen-induced arthritis (CIA) mice. Alamandine (0.1, 1 and 10 µg/ml) did not affect the survival of the synovial fibroblasts, but decreased the migration and proinflammatory cytokines expression in TNF-α (10 ng/ml) stimulated cells in vitro. Additionally, alamandine selectively decreased phosphorylated-JNK expression induced by TNF-a stimulation in RA FLS. DBA/1 J mice were induced arthritis by a primary injection with an emulsion of bovine type II collagen (CII) and complete Freund's adjuvant (day 0) and a booster injection of CII in incomplete Freund's adjuvant (day 21). Mice were then given alamandine intraperitoneally in saline (50 μg/kg/day) from days 21-42. Histology and multiplex immunobead assay showed that alamandine treatment inhibited the development of arthritis and reduced the joint damage. This effect was accompanied by the reduced inflammatory cytokines (IL-6, IL-23, IFN-γ) mRNA expression in local joints, the decreased TNF-α, IL-6, IL-17 and the increased IL-10 levels in the serum from alamandine administrated CIA mice. In conclusion, alamandine attenuates the development of arthritis by suppressing inflammatory cytokines expression in RA synovial fibroblasts via MAPK signaling pathway, suggesting a potential therapeutic role for RA.

Interleukin-10 family members: Biology and role in the bone and joint diseases

Interleukin (IL)-10 family cytokines include IL-10, IL-19, IL-20, IL-22, IL-24, IL-26, IL-28A, IL-28B, and IL-29. These cytokines play crucial regulatory roles in various biological reactions and diseases. In recent years, several studies have shown that the IL-10 family plays a vital role in bone and joint diseases, including bone metabolic diseases, fractures, osteoarthritis, rheumatoid arthritis, and bone tumors. Herein, the recent progress on the regulatory role of IL-10 family of cytokines in the occurrence and development of bone and joint diseases has been summarized. This review will provide novel directions for immunotherapy of bone and joint diseases.

Elucidating the role of hypoxia-inducible factor in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic multifactorial disease, provocative, and degenerative autoimmune condition that impacts millions of individuals around the globe. As a result of this understanding, anti-inflammatory drugs have been created, perhaps widely effective (like steroids) and highly specialized methods (including anti-TNF antibody) using biological therapies (including TNF inhibitors). Despite this, the connections between inflammatory response, articular development, and intracellular responsiveness to changes in oxygen concentration are undervalued in rheumatoid arthritis. Hypoxia, or a lack of oxygen, is thought to cause enhanced synovial angiogenesis in RA, which is mediated by some of the hypoxia-inducible factors like vascular endothelial growth factor (VEGF). Substantial genetic alterations occur when the HIF regulatory factors signaling cycle is activated, allowing organelles, tissues, and species to acclimatize to decreasing oxygen saturation. The most well-characterized hypoxia-responsive transcripts are the angiogenic stimulant VEGF, whose production is greatly elevated by hypoxia in several types of cells, especially RA synovium fibroblasts. Blocking vascular endothelial growth factors has been demonstrated to be helpful in murine models of rheumatism, indicating how hypoxia could trigger the angiogenesis process, resulting in the progression of RA. These mechanisms highlight the intimate affiliation amongst hypoxia, angiogenesis, and inflammation in rheumatoid arthritis. This review will look at how hypoxia activates molecular pathways and how other pathways involving inflammatory signals develop and sustain synovitis in rheumatoid arthritis.

The Role of Medicinal and Aromatic Plants against Obesity and Arthritis: A Review

Obesity is a significant health concern, as it causes a massive cascade of chronic inflammations and multiple morbidities. Rheumatoid arthritis and osteoarthritis are chronic inflammatory conditions and often manifest as comorbidities of obesity. Adipose tissues serve as a reservoir of energy as well as releasing several inflammatory cytokines (including IL-6, IFN-γ, and TNF-α) that stimulate low-grade chronic inflammatory conditions such as rheumatoid arthritis, osteoarthritis, diabetes, hypertension, cardiovascular disorders, fatty liver disease, oxidative stress, and chronic kidney diseases. Dietary intake, low physical activity, unhealthy lifestyle, smoking, alcohol consumption, and genetic and environmental factors can influence obesity and arthritis. Current arthritis management using modern medicines produces various adverse reactions. Medicinal plants have been a significant part of traditional medicine, and various plants and phytochemicals have shown effectiveness against arthritis and obesity; however, scientifically, this traditional plant-based treatment option needs validation through proper clinical trials and toxicity tests. In addition, essential oils obtained from aromatic plants are being widely used as for complementary therapy (e.g., aromatherapy, smelling, spicing, and consumption with food) against arthritis and obesity; scientific evidence is necessary to support their effectiveness. This review is an attempt to understand the pathophysiological connections between obesity and arthritis, and describes treatment options derived from medicinal, spice, and aromatic plants.

Molecular and Cellular Heterogeneity in Rheumatoid Arthritis: Mechanisms and Clinical Implications

Rheumatoid arthritis is an autoimmune disease that exhibits significant clinical heterogeneity. There are various treatments for rheumatoid arthritis, including disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and inflammatory cytokine inhibitors (ICI), typically associated with differentiated clinical effects and characteristics. Personalized responsiveness is observed to the standard treatment due to the pathophysiological heterogeneity in rheumatoid arthritis, resulting in an overall poor prognosis. Understanding the role of individual variation in cellular and molecular mechanisms related to rheumatoid arthritis will considerably improve clinical care and patient outcomes. In this review, we discuss the source of pathophysiological heterogeneity derived from genetic, molecular, and cellular heterogeneity and their possible impact on precision medicine and personalized treatment of rheumatoid arthritis. We provide emphasized description of the heterogeneity derived from mast cells, monocyte cell, macrophage fibroblast-like synoviocytes and, interactions within immune cells and with inflammatory cytokines, as well as the potential as a new therapeutic target to develop a novel treatment approach. Finally, we summarize the latest clinical trials of treatment options for rheumatoid arthritis and provide a suggestive framework for implementing preclinical and clinical experimental results into clinical practice.

Targeting Probiotics in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a progressive inflammatory disorder characterized by swollen joints, discomfort, tightness, bone degeneration and frailty. Genetic, agamogenetic and sex-specific variables, Prevotella, diet, oral health and gut microbiota imbalance are all likely causes of the onset or development of RA, perhaps the specific pathways remain unknown. Lactobacillus spp. probiotics are often utilized as relief or dietary supplements to treat bowel diseases, build a strong immune system and sustain the immune system. At present, the action mechanism of Lactobacillus spp. towards RA remains unknown. Therefore, researchers conclude the latest analysis to effectively comprehend the ultimate pathogenicity of rheumatoid arthritis, as well as the functions of probiotics, specifically Lactobacillus casei or Lactobacillus acidophilus, in the treatment of RA in therapeutic and diagnostic reports. RA is a chronic inflammation immunological illness wherein the gut microbiota is affected. Probiotics are organisms that can regulate gut microbiota, which may assist to relieve RA manifestations. Over the last two decades, there has been a surge in the use of probiotics. However, just a few research have considered the effect of probiotic administration on the treatment and prevention of arthritis. Randomized regulated experimental trials have shown that particular probiotics supplement has anti-inflammatory benefits, helps people with RA enhance daily activities and alleviates symptoms. As a result, utilizing probiotic microorganisms as therapeutics could be a potential possibility for arthritis treatment. This review highlights the known data on the therapeutic and preventative effects of probiotics in RA, as well as their interactions.

Enhanced serum interferon-lambda 1 interleukin-29 levels in patients with psoriasis vulgaris

BACKGROUND

Interferon (IFN)-λ1, also named Interleukin (IL)-29, is a new member of the Type III IFN or IFN-λ family. IL-29 plays an important role in the pathogenesis of many types of autoimmune and inflammatory diseases.

OBJECTIVE

To study the role of IL-29 in the pathogenesis of psoriasis vulgaris.

METHODS

The authors detected the serum levels of IL-29 in forty-one patients with psoriasis vulgaris, twenty-three patients with atopic dermatitis and thirty-eight age and gender-matched controls by sandwich Enzyme-Linked Immunosorbent Assay (ELISA). The effects of IL-29 on the expression of cytokines, such as IL-6, IL-17, IL-8, IL-4, IL10, Interferon (IFN-γ) and Tumor Necrosis Factor-α (TNF-α), in PBMCs and HaCat cells were determined by real-time quantitative PCR.

RESULTS

Our data indicated that serum IL-29 levels were significantly elevated in patients with psoriasis vulgaris when compared with atopic dermatitis patients and the control group. Moreover, Serum levels of IL-29 were closely associated with the severity of psoriasis vulgaris. Furthermore, IL-29 up-regulated the mRNA expression levels of IL-6, IL-17 and TNF-α in PBMCs from psoriasis vulgaris patients. In addition, IL-29 enhanced the IL-6 and IL-8 expression from the HaCat cells.

CONCLUSION

This study provides the first observations on the association of IL-29 and psoriasis vulgaris and showed elevated IL-29 serum levels. The authors suggest that IL-29 may play a role in the pathogenesis of psoriasis vulgaris.

Interferon lambda in inflammation and autoimmune rheumatic diseases

Interferons are potent antiviral cytokines that modulate immunity in response to infection or other danger signals. In addition to their antiviral functions, type I interferons (IFNα and IFNβ) are important in the pathogenesis of autoimmune diseases. Type III interferons (IFNλs) were initially described as a specialized system that inhibits viral replication at epithelial barrier surfaces while limiting inflammatory damage. However, evidence now suggests that type III interferons have complex effects on both innate and adaptive immune responses and might also be pathogenic in systemic autoimmune diseases. Concentrations of IFNλs are increased in blood and tissues in a number of autoimmune rheumatic diseases, including systemic lupus erythematosus, and are further associated with specific clinical and laboratory parameters. This Review is aimed at providing a critical evaluation of the current literature on IFNλ biology and how type III interferons might contribute to immune dysregulation and tissue damage in autoimmunity. The potential effects of type III interferons on treatment strategies for autoimmune rheumatic diseases, such as interferon blockade, are also considered.

Tofacitinib downregulates antiviral immune defence in keratinocytes and reduces T cell activation

BACKGROUND

Tofacitinib is a novel Janus kinase (JAK) inhibitor approved for the treatment of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. In clinical trials, the most common adverse events observed were nasopharyngitis, upper respiratory tract infections, and zoster. JAKs are found downstream of the type II cytokine receptor family used by a number of TH17 cell-associated cytokines for signal transduction. These cytokines lead to the secretion of antiviral and antimicrobial peptides (AMPs) by keratinocytes or synoviocytes. Blocking the JAK pathway might result in a diminished secretion of antimicrobial and antiviral peptides causing higher susceptibility to infections in patients treated with JAK inhibitors.

METHODS

We treated primary human keratinocytes and synoviocytes with tofacitinib and subsequently added various cytokines and bacterial surface proteins before evaluation of the response via RT-qPCR. CD69 expression on tofacitinib-treated PBMCs was investigated via flow cytometry.

RESULTS

We found a markedly reduced gene expression of all tested antiviral peptides such as MX1 or ISG15 in keratinocytes and synoviocytes in the presence of tofacitinib in vitro. Additionally, we found that JAK inhibition reduced activation of T cells after stimulation with bacterial LPS or viral VZV gE.

CONCLUSIONS

The antiviral immunity is strongly inhibited in the presence of tofacitinib in vitro, while the antimicrobial immunity does not seem to be affected. In T cells, the overall activation process seems to be influenced by tofacitinib. These findings suggest that tofacitinib has an impact on antiviral immunity such as patients treated with tofacitinib often show adverse events like herpes zoster.

Probiotics and Amelioration of Rheumatoid Arthritis: Significant Roles of Lactobacillus casei and Lactobacillus acidophilus

Rheumatoid arthritis is a chronic autoimmune disorder that can lead to disability conditions with swollen joints, pain, stiffness, cartilage degradation, and osteoporosis. Genetic, epigenetic, sex-specific factors, smoking, air pollution, food, oral hygiene, periodontitis, Prevotella, and imbalance in the gastrointestinal microbiota are possible sources of the initiation or progression of rheumatoid arthritis, although the detailed mechanisms still need to be elucidated. Probiotics containing Lactobacillus spp. are commonly used as alleviating agents or food supplements to manage diarrhea, dysentery, develop immunity, and maintain general health. The mechanism of action of Lactobacillus spp. against rheumatoid arthritis is still not clearly known to date. In this narrative review, we recapitulate the findings of recent studies to understand the overall pathogenesis of rheumatoid arthritis and the roles of probiotics, particularly L. casei or L. acidophilus, in the management of rheumatoid arthritis in clinical and preclinical studies.

The Dramatic Role of IFN Family in Aberrant Inflammatory Osteolysis

Skeletal system has been considered a highly dynamic system, in which bone-forming osteoblasts and bone-resorbing osteoclasts go through a continuous remodeling cycle to maintain homeostasis of bone matrix. It has been well acknowledged that interferons (IFNs), acting as a subgroup of cytokines, not only have crucial effects on regulating immunology but also could modulate the dynamic balance of bone matrix. In the light of different isoforms, IFNs have been divided into three major categories in terms of amino acid sequences, recognition of specific receptors and biological activities. Currently, type I IFNs consist of a multi-gene family with several subtypes, of which IFN-α exerts pro-osteoblastogenic effects to activate osteoblast differentiation and inhibits osteoclast fusion to maintain bone matrix integrity. Meanwhile, IFN-β suppresses osteoblast-mediated bone remodeling as well as exhibits inhibitory effects on osteoclast differentiation to attenuate bone resorption. Type II IFN constitutes the only type, IFN-γ, which exerts regulatory effects on osteoclastic bone resorption and osteoblastic bone formation by biphasic ways. Interestingly, type III IFNs are regarded as new members of IFN family composed of four members, including IFN-λ1 (IL-29), IFN-λ2 (IL-28A), IFN-λ3 (IL-28B) and IFN-λ4, which have been certified to participate in bone destruction. However, the direct regulatory mechanisms underlying how type III IFNs modulate the metabolic balance of bone matrix, remains poorly elucidated. In this review, we have summarized functions of IFN family during physiological and pathological conditions and described the mechanisms by which IFNs maintain bone matrix homeostasis via affecting the osteoclast-osteoblast crosstalk. In addition, the potential therapeutic effects of IFNs on inflammatory bone destruction diseases such as rheumatoid arthritis (RA), osteoarthritis (OA) and infectious bone diseases are also well displayed, which are based on the predominant role of IFNs in modulating the dynamic equilibrium of bone matrix.

Interleukin-29 and interleukin-28A induce migration of neutrophils in rheumatoid arthritis

OBJECTIVES

Type III Interferons, interleukin (IL)-29 and IL-28A, have been implicated in the inflammatory response of rheumatoid arthritis (RA). Increasing evidence suggests an important role of neutrophils in the pathogenesis of RA. However, the underlying mechanism remains unclear. Therefore, we investigated the expression of the receptor of these type III interferons, IL-28R1, on the neutrophils of RA patients, and further explored the roles of IL-29 and IL-28A on neutrophil activity.

METHODS

Neutrophils were extracted from peripheral blood of patients who met the diagnostic criteria for RA and healthy controls. The serum levels of IL-29 and IL-28A in RA patients and healthy controls were examined by enzyme-linked immunoassay, and the expression of IL-28R1 on neutrophils was determined by flow cytometry. A transwell assay was performed to determine the chemotactic ability of IL-29 and IL-28A to neutrophils in RA patients.

RESULTS

The serum IL-29 but not IL-28A levels were significantly elevated in RA patients, and neither was correlated with RA disease activity. IL-28R1 levels on neutrophils were significantly (p < 0.001) elevated in patients with RA (51.85% (36.10%, 67.03%)) compared with those of healthy controls (4.13% (3.54%, 7.96%)), and IL-29 and IL-28A had a significant chemotactic effect on neutrophils from the peripheral blood of RA patients.

CONCLUSION

IL-29 and IL-28A play an important role in regulating neutrophils which participate in the pathogenesis of RA. Therefore, inhibiting IL-29 and IL-28A may be a new therapeutic strategy for RA. Key points • The IL-28R1 levels were increased in neutrophils of RA patients, suggesting its potentially important role in the pathogenesis of RA. • IL-29 and IL-28A induce the migration of neutrophils that participate in the development of RA.

Estrogen downregulates TAK1 expression in human fibroblast-like synoviocytes and in a rheumatoid arthritis model

Transforming growth factor β-activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase family, plays a key role in the pathogenesis and progression of rheumatoid arthritis (RA). Estrogen has been previously reported to delay arthritis progression. However, the exact association between TAK1 and estrogen remains elusive. The present study demonstrated that TAK1 was upregulated in synoviocytes of patients with RA compared with patients with osteoarthritis and healthy controls. In addition, TAK1 was also expressed in cultured fibroblast-like synoviocytes (FLS), and its levels decreased significantly in 17β-estradiol (E2)-treated cells in a dose-dependent manner. Furthermore, administration of E2 significantly decreased TAK1 expression and attenuated the development of collagen-induced arthritis (CIA). Taken together, the findings of the present study suggested that E2 mediates a decrease of TAK1 in both FLS and CIA, which subsequently results in a suppression of the pathological process of CIA. Therefore, estrogen may serve as a potential therapeutic agent for the treatment of RA by targeting TAK1.

MiR-20a inhibits the progression of human arthritis fibroblast-like synoviocytes and inflammatory factor expression by targeting ADAM10

MiR-20a has been reported as a key regulator to pro-inflammatory factor release in fibroblast-like synoviocytes (FLS), which caused rheumatoid arthritis (RA). However, the molecular mechanism of miR-20a in RA remains to be further elucidated. This study aimed to investigate the roles of miR-20a in RA pathology. RA (n = 24) and osteoarthritis (OA, n = 20) and normal healthy tissues (n = 16) were collected from operation. TargetScan and dual-luciferase reporter were performed to predict and confirm the potential binding sites of miR-20a on ADAM metallopeptidase domain 10 (ADAM10). Pearson's analysis was adopted to evaluate the correlation between miR-20a and ADAM10 expression. It was found that MiR-20a was downregulated in RA tissues, and overexpressed miR-20a inhibited cell viability, migration and invasion, and the expression of inflammatory factors in RA-FLS MH7A cells. ADAM10 was identified as the target gene of miR-20a, and upregulation of ADAM10 reversed the inhibitory effects of miR-20a. In conclusion, miR-20a inhibits the progression of RA-FLS as well as the inflammatory factor expression by targeting ADAM10.

Sensitivity and specificity of Interleukin 29 in patients with rheumatoid arthritis and other rheumatic diseases

BACKGROUND

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic and progressive inflammation that can cause a high degree of disability in affected individuals. Proinflammatory cytokines play central roles in the development of degradative and inflammatory responses in RA. IL-29 has been identified in RA and reported as a biomarker of the disease.

OBJECTIVE

To analyze serum levels and accuracy of IL-29 in RA patients compared to healthy subjects and patients with other rheumatic diseases.

METHODS

IL-29 serum levels were measured in 121 patients with RA, 53 patients with systemic lupus erythematosus (SLE), 60 patients with systemic sclerosis (SSc), 29 patients with fibromyalgia (FM), 50 patients with osteoarthritis (OA) and 68 healthy individuals as controls. IL-29 levels in serum were investigated by ELISA. Sensitivity, specificity and likelihood ratios (LR) for having RA were calculated.

RESULTS

Serum levels of IL-29 were increased in RA patients 113.6 (IQR = 31.25-308.5) pg/ml compared to non-RA patients (SLE, SSc, OA, and FM) (31.25 pg/ml) and healthy controls (31.25 pg/ml, p < 0.001). The IL-29 cut-off values to distinguish patients with RA from non-RA patients were 61.11 pg/ml (sensitivity 57.02, specificity 92.71, LR: 7.82) and for all subjects 32.96 pg/ml (sensitivity 64.46, specificity 87.31, LR: 5.08). Additionally, IL-29 correlated negatively with age (r=-0189, p = 0.038) and disease duration (-0.192, p = 0.037). Interestingly, IL-29 correlated positively with neutrophil count in RA patients positive for rheumatoid factor (r = 0.259, p = 0.022).

CONCLUSION

IL-29 is higher in the serum of patients with RA compared to non-RA subjects and may have potential for use as a biological marker.

Type III Interferons (Lambda Interferons) in Rheumatic Autoimmune Diseases

The last 2 decades have witnessed the discovery and characterization of a new family of cytokines with immunological characteristics similar to those described for type I interferons, type III or lambda interferons. Unraveling the molecular mechanisms underlying each type of interferon has allowed us to understand how some autoimmune diseases can be considered as interferonopathies. Under normal conditions, type III interferons play a key role in the defense against viruses by modulating the functioning of several types of innate and adaptive immune cells. These effects include upregulation of major histocompatibility complex molecules by myeloid dendritic cells, increased functioning of pattern recognition receptors by plasmacytoid dendritic cells, decreased activity of regulatory T cells, enhanced production of antibodies by plasmatic cells and increased expression of chemokines and adhesion molecules by leukocytes and endothelial cells. Notably, all these mechanisms have been described to boost autoimmunity, and type III interferons pathway activation has been related to the pathogenesis of autoimmune conditions such as systemic lupus erythematosus, systemic sclerosis and Sjögren's syndrome. This review provides an overview of the current evidence on the contribution of type III interferons in the pathogenesis of rheumatic autoimmune diseases in humans.

RA-map: building a state-of-the-art interactive knowledge base for rheumatoid arthritis

Rheumatoid arthritis (RA) is a progressive, inflammatory autoimmune disease of unknown aetiology. The complex mechanism of aetiopathogenesis, progress and chronicity of the disease involves genetic, epigenetic and environmental factors. To understand the molecular mechanisms underlying disease phenotypes, one has to place implicated factors in their functional context. However, integration and organization of such data in a systematic manner remains a challenging task. Molecular maps are widely used in biology to provide a useful and intuitive way of depicting a variety of biological processes and disease mechanisms. Recent large-scale collaborative efforts such as the Disease Maps Project demonstrate the utility of such maps as versatile tools to organize and formalize disease-specific knowledge in a comprehensive way, both human and machine-readable. We present a systematic effort to construct a fully annotated, expert validated, state-of-the-art knowledge base for RA in the form of a molecular map. The RA map illustrates molecular and signalling pathways implicated in the disease. Signal transduction is depicted from receptors to the nucleus using the Systems Biology Graphical Notation (SBGN) standard representation. High-quality manual curation, use of only human-specific studies and focus on small-scale experiments aim to limit false positives in the map. The state-of-the-art molecular map for RA, using information from 353 peer-reviewed scientific publications, comprises 506 species, 446 reactions and 8 phenotypes. The species in the map are classified to 303 proteins, 61 complexes, 106 genes, 106 RNA entities, 2 ions and 7 simple molecules. The RA map is available online at ramap.elixir-luxembourg.org as an open-access knowledge base allowing for easy navigation and search of molecular pathways implicated in the disease. Furthermore, the RA map can serve as a template for omics data visualization.

Insights into IL-29: Emerging role in inflammatory autoimmune diseases

Interleukin-29 (IL-29) is a newly discovered member of type III interferon. It mediates signal transduction via binding to its receptor complex and activates downstream signalling pathways, and therefore induces the generation of inflammatory components. Recent studies reported that expression of IL-29 is dysregulated in inflammatory autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, Sjögren's syndrome, psoriasis and systemic sclerosis. Furthermore, functional analysis revealed that IL-29 may involve in the pathogenesis of the inflammatory autoimmune disorders. In this review, we will systematically review the current knowledge about IL-29. The information collected revealed the regulatory role of IL-29 and may give important implications for its potential in clinical treatment.

Exosome-encapsulated miR-6089 regulates inflammatory response via targeting TLR4

Exosome-encapsulated microRNAs (miRNAs) have been identified as potential biomarkers in autoimmune diseases. However, little is known about the role of exosome-delivered miRNAs in rheumatoid arthritis (RA). In this study, we investigated the profile of specific exosomal miRNAs by microarray analysis of serum exosomes from three patients with RA and three healthy controls. Quantitative real-time PCR (qRT-PCR) was performed to validate the aberrantly expressed exosomal miRNAs. A total of 20 exosome-encapsulated miRNAs were identified to be differently expressed in the serum of patients with RA compared with controls. Interestingly, we found that exosome-encapsulated miR-6089 was significantly decreased after validation by qRT-PCR in serum exosomes from 76 patients with RA and 20 controls. Besides, miR-6089 could inhibit lipopolysaccharide (LPS)-induced cell proliferation and activation of macrophage-like THP-1 cells. TLR4 was a direct target for miR-6089. MiR-6089 regulated the generation of IL-6, IL-29, and TNF-α by targetedly controlling TLR4 signaling. In conclusion, exosome-encapsulated miR-6089 regulates LPS/TLR4-mediated inflammatory response, which may serve as a novel, promising biomarker in RA.

The KH-type splicing regulatory protein (KSRP) regulates type III interferon expression post-transcriptionally

Type III interferons (IFNs) are the latest members of the IFN family. They play an important role in immune defense mechanisms, especially in antiviral responses at mucosal sites. Moreover, they control inflammatory reactions by modulating neutrophil and dendritic cell functions. Therefore, it is important to identify cellular mechanisms involved in the control of type III IFN expression. All IFN family members contain AU-rich elements (AREs) in the 3'-untranslated regions (3'-UTR) of their mRNAs that determine mRNA half-life and consequently the expressional level of these cytokines. mRNA stability is controlled by different proteins binding to these AREs leading to either stabilization or destabilization of the respective target mRNA. The KH-type splicing regulatory protein KSRP (also named KHSRP) is an important negative regulator of ARE-containing mRNAs. Here, we identify the interferon lambda 3 (IFNL3) mRNA as a new KSRP target by pull-down and immunoprecipitation experiments, as well as luciferase reporter gene assays. We characterize the KSRP-binding site in the IFNL3 3'-UTR and demonstrate that KSRP regulates the mRNA half-life of the IFNL3 transcript. In addition, we detect enhanced expression of IFNL3 mRNA in KSRP-/- mice, establishing a negative regulatory function of KSRP in type III IFN expression also in vivo Besides KSRP the RNA-binding protein AUF1 (AU-rich element RNA-binding protein 1) also seems to be involved in the regulation of type III IFN mRNA expression.

Interleukin 29 inhibits RANKL-induced osteoclastogenesis via activation of JNK and STAT, and inhibition of NF-κB and NFATc1

Interleukin (IL)-29 is known to modulate immune functions of monocytes or macrophages. In this study, we investigated the effect and its underlying mechanism of IL-29 on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis using murine macrophage cell line RAW264.7 cells and bone-marrow-derived monocyte/macrophage precursor cells (BMMs), and human peripheral blood mononuclear cells (PBMCs). In response to human recombinant IL-29, cell viability and apoptosis were assessed by Cell Counting Kit-8 and flow cytometry; the osteoclast formation and activity by tartrate-resistant acid phosphatase (TRAP) staining and pit formation assay, respectively; the expression and activation of molecules that associated with osteoclastogenesis by real time-PCR, immunoblotting or immunofluorescent analysis. IL-28 receptor α (IL-28Rα), a specific receptor of IL-29 was expressed on RAW264.7 cells. Although IL-29 did not affect the viability and apoptosis of RAW264.7 cells, it inhibited multinucleated cells in the differentiation of osteoclastogenesis, the bone-resorbing activity of mature osteoclasts and osteoclastic specific genes expression including TRAP, cathepsin K (CTSK), nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), C-Fos and matrix metallopeptidase 9 (MMP-9). This inhibitory effect of IL-29 was confirmed on BMMs and PBMCs and mediated via IL-28Rα through the activation of Stat1 and 3 and the suppression of nuclear factor kappa B (NF-κB) and NFATc1 nuclear translocation in RAW264.7 cells. In conclusion, IL-29 inhibited osteoclastogenesis via activation of STAT signaling pathway, prevention of NF-κB activation and NFATc1 translocation, and suppression of downstream osteoclastogenic genes expression.

High-Throughput Study of the Effects of Celastrol on Activated Fibroblast-Like Synoviocytes from Patients with Rheumatoid Arthritis

Celastrol, a natural triterpene, exhibits potential anti-inflammatory activity in a variety of inflammatory diseases. The present study aimed to investigate its biological effect on activated fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA). The primary FLSs of the synovial tissues were obtained from synovial biopsies of patients with RA. The normal human FLS line (HFLS) was used as a control. After the RA–FLSs and HFLSs were treated with or without celastrol, various approaches, including the WST-1 assay, transwell assay, real-time PCR and ELISA analysis, were performed to estimate proliferation, invasion and expression of pro-inflammatory cytokines of the RA–FLSs. Microarray analysis was performed to screen for differentially expressed genes in RA–FLSs before and after celastrol treatment. The results showed that treatment of celastrol attenuated both the proliferation and invasion of the RA–FLSs. The expression of several chemokine genes, including CCL2, CXCL10, CXCL12, CCR2 and CXCR4, was significantly changed after celastrol treatment. The genes involved in the NF-κB signaling pathway appeared to be regulated by celastrol.

Long noncoding RNAs expression profile and functional networks in rheumatoid arthritis

The modifying effects of long noncoding RNAs (lncRNAs) in rheumatoid arthritis (RA) recently have drawn much attention; however, the underlying mechanisms remain largely unknown. Herein, we aim to investigate the expression profile of lncRNAs in RA and identify promising targets for RA diagnosis and treatment. Microarray screening and real-time PCR of lncRNAs were performed by use of serum samples from 3 RA patients and 3 healthy controls. Significantly differentially expressed lncRNAs were verified in serum samples from 43 RA patients and 40 healthy controls by real-time PCR. We found that there were 73 up-regulated and 61 down-regulated lncRNAs as well as 128 up-regulated and 37 down-regulated mRNAs in serum samples of RA patients. Validation in RA clinical samples indicated 5 of these lncRNAs were significantly up-regulated including RNA143598, RNA143596, HIX0032090, IGHCgamma1, and XLOC_002730. Significant association was observed between these lncRNAs and the disease course, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) as well as anti-cyclic citrullinated peptide (anti-CCP) antibody. Additionally, 55 of the differentially expressed mRNAs were associated with 41 lncRNAs and were involved in signaling pathways of toll like receptors (TLRs), nuclear factor-kappa B (NF-κB), and cytokine, especially the IRF3/IRF7 mediated signaling transduction. Our study firstly shows the specific profile of lncRNAs in the serum of RA patients and potential signaling pathways involved in RA pathogenesis, which may provide novel targets for the diagnosis and treatment of patients with RA.

Down-regulation of miR-10a-5p in synoviocytes contributes to TBX5-controlled joint inflammation

MicroRNAs are considered to play critical roles in the pathogenesis of human inflammatory arthritis, including rheumatoid arthritis (RA). The purpose of this study was to determine the relationship between miR‐10a‐5p and TBX5 in synoviocytes and evaluate their contribution to joint inflammation. The expression of miR‐10a‐5p and TBX5 in the synovium of RA and human synovial sarcoma cell line SW982 stimulated by IL‐1β was determined by RT‐qPCR and Western blotting. The direct interaction between miR‐10a‐5p and TBX5 3′UTR was determined by dual‐luciferase reporter assay in HeLa cells. Mimics and inhibitors of miR‐10a‐5p were transfected into SW982 cells. TBX5 was overexpressed by plasmid transfection or knocked down by RNAi. Proinflammatory cytokines and TLR3 and MMP13 expressions were determined by RT‐qPCR and Western blotting. Down‐regulated expression of miR‐10a‐5p and up‐regulation of TBX5 in human patients with RA were found compared to patients with OA. IL‐1β could reduce miR‐10a‐5p and increase TBX5 expression in SW982 cells in vitro. The direct target relationship between miR‐10a‐5p and 3′UTR of TBX5 was confirmed by luciferase reporter assay. Alterations of miR‐10‐5p after transfection with its mimic and inhibitor caused the related depression and re‐expression of TBX5 and inflammatory factors in SW982 cells. Overexpression of TBX5 after pCMV3‐TBX5 plasmid transfection significantly promoted the production of TLR3, MMP13 and various inflammatory cytokines, while this effect was rescued after knocking down of TBX5 with its specific siRNA. We conclude that miR‐10a‐5p in a relation with TBX5 regulates joint inflammation in arthritis, which would serve as a diagnostic and therapeutic target for RA treatment.

IL-29 Enhances CXCL10 Production in TNF-α-stimulated Human Oral Epithelial Cells

Interleukin-29 (IL-29) is a cytokine belonging to the Type III interferon family. It was recently detected in the gingival crevicular fluid of periodontitis patients. However, the role of IL-29 in the pathogenesis of periodontal disease remains unknown. The aim of this study was to examine the effects of IL-29 on C-X-C motif chemokine ligand 10 (CXCL10) production in human oral epithelial cells. We measured CXCL10 production in TR146 cells, which is a human oral epithelial cell line, using an enzyme-linked immunosorbent assay. We used a Western blot analysis to detect IL-29 receptor expression and the phosphorylation levels of signal transduction molecules, including p38 mitogen-activated protein kinases (MAPK), signal transducer and activator of transcription 3 (STAT3), and nuclear factor (NF)- κB p65, in the TR146 cells. The TR146 cells expressed the IL-29 receptor. IL-29 induced CXCL10 production in the TR146 cells. IL-29 significantly enhanced CXCL10 production in tumor necrosis factor (TNF)-α-stimulated TR146 cells. The p38 MAPK, STAT3, and NF-κB pathways were found to be related to the IL-29-induced enhancement of CXCL10 production in TNF-α-stimulated TR146 cells. IL-29 promotes T helper 1-cell accumulation in periodontal lesions by inducing CXCL10 production in oral epithelial cells.

Type-III interferons and rheumatoid arthritis: Correlation between interferon lambda 1 (interleukin 29) and antimutated citrullinated vimentin antibody levels

AIM

To assess serum type III or lambda (λ) interferons (IFN) levels and its clinical and laboratory associations in rheumatoid arthritis (RA).

METHODS

A cross-sectional study including 43 patients with RA (86% females; age 45.3 ± 10.3 years) and 43 healthy individuals was performed. Clinical data including disease activity, acute-phase reactants, rheumatoid factor and anticyclic citrullinated peptide (anti-CCP) antibodies were collected. Serum IFNλ1, IFNλ2, IFNλ3, CXCL8 and anti-mutated citrullinated vimentin (anti-MCV) antibody levels were measured.

RESULTS

Patients with RA had higher IFNλ1 (113.5 ± 118.6 pg/mL versus 55.9 ± 122.3 pg/mL; p < 0.0001) and IFNλ2 (245.4 ± 327.7 pg/mL versus 5.1 ± 11.0 pg/mL; p = 0.009) levels than controls, but not IFNλ3 levels. Notably, IFNλ1 levels were found to be higher in both patients with active disease (124.9 ± 135.9 pg/mL; p < 0.001) and quiescent disease (99.0 ± 93.7 pg/mL; p < 0.01), while IFNλ2 levels were higher only in patients with active disease (264.0 ± 356.1 pg/mL; p = 0.02). A noteworthy association between serum IFNλ1 levels and anti-MCV antibody titers (Spearman's rho coefficient 0.36, 95% CI 0.36 to 0.61; p = 0.02) was observed.

CONCLUSION

Serum IFNλ1 and IFNλ2 levels are abnormally elevated in patients with RA and the former are linearly associated with circulating anti-MCV antibody levels. These results may place type-III IFN as an attractive new therapeutic target in RA.

TLRs, future potential therapeutic targets for RA

Toll like receptors (TLR)s have a central role in regulating innate immunity and in the last decade studies have begun to reveal their significance in potentiating autoimmune diseases such as rheumatoid arthritis (RA). Earlier investigations have highlighted the importance of TLR2 and TLR4 function in RA pathogenesis. In this review, we discuss the newer data that indicate roles for TLR5 and TLR7 in RA and its preclinical models. We evaluate the pathogenicity of TLRs in RA myeloid cells, synovial tissue fibroblasts, T cells, osteoclast progenitor cells and endothelial cells. These observations establish that ligation of TLRs can transform RA myeloid cells into M1 macrophages and that the inflammatory factors secreted from M1 and RA synovial tissue fibroblasts participate in TH-17 cell development. From the investigations conducted in RA preclinical models, we conclude that TLR-mediated inflammation can result in osteoclastic bone erosion by interconnecting the myeloid and TH-17 cell response to joint vascularization. In light of emerging unique aspects of TLR function, we summarize the novel approaches that are being tested to impair TLR activation in RA patients.

Anti-Inflammatory Effects of TRAF-Interacting Protein in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease characterized by inflammatory cell infiltration, synovial inflammation, and cartilage destruction. Proliferative fibroblast-like synoviocytes (FLS) play crucial roles in both propagation of inflammation and joint damage because of their production of great amount of proinflammatory cytokines and proteolytic enzymes. In this study, we investigate the role of TRAF-interacting protein (TRIP) in regulating inflammatory process in RA-FLS. TRIP expression was attenuated in RA-FLS compared with osteoarthritis- (OA-) FLS. Overexpression of TRIP significantly inhibited the activation of NF-κB signaling and decreased the production of proinflammatory cytokines and matrix metalloproteinases (MMPs) in TNFα-stimulated RA-FLS. Furthermore, TRIP was found to interact with transforming growth factor β-activated kinase 1 (TAK1) and promoting K48-linked polyubiquitination of TAK1 in RA-FLS. Our results demonstrate that TRIP has anti-inflammatory effects on RA-FLS and suggest TRIP as a potential therapeutic target for human RA.

The role of IL-29 in immunity and cancer

Interleukin-29 (IL-29) is a new member of the recently discovered interferon λ (IFNλ) family. It is produced predominantly by maturing dendritic cells and macrophages. It has been implicated in numerous immunological responses and has shown antiviral activity similar to the Type I interferons, although its target cell population is more limited than the Type I interferons. In recent years, the role of IL-29 in the pathogenesis of various cancers has also been extensively studied. In this review, we will discuss the recent advances of IL-29 in immunological processes and the pathogenesis of various cancer.

Toll-like receptors in the pathogenesis of autoimmune diseases: recent and emerging translational developments

Autoinflammatory diseases are defined as the loss of self-tolerance in which an inflammatory response to self-antigens occurs, which are a significant global burden. Toll-like receptors are key pattern recognition receptors, which integrate signals leading to the activation of transcription factors and ultimately proinflammatory cytokines. Recently, it has become apparent that these are at the nexus of autoinflammatory diseases making them viable and attractive drug targets. The aim of this review was to evaluate the role of innate immunity in autoinflammatory conditions alongside the role of negative regulation while suggesting possible therapeutic targets.

Ocular Fluid Analysis in Children Reveals Interleukin-29/Interferon-λ1 as a Biomarker for Juvenile Idiopathic Arthritis-Associated Uveitis

OBJECTIVE

Childhood uveitis is a vision-threatening inflammatory eye disease commonly attributed to juvenile idiopathic arthritis (JIA). The pathogenesis is poorly understood, which makes clinical management challenging. We analyzed soluble mediators in ocular fluid (aqueous humor [AqH]) and serum from children with JIA-associated uveitis and common childhood uveitis to identify potential biomarkers and investigate the ocular microenvironment of this sight-threatening eye disease.

METHODS

AqH (n = 73) and paired serum (n = 66) samples were analyzed for 51 soluble mediators of inflammation by multiplex immunoassay. Twenty-one children with JIA-associated uveitis were compared to 15 children with chronic anterior uveitis without arthritis, 29 children with noninfectious idiopathic uveitis, and 8 children with noninflammatory conditions (controls). For visualization of the joint effect of multiple mediators, we used the radial coordinate visualization (Radviz) method. Optimal biomarker level cutoffs were also determined.

RESULTS

The levels of interleukin-29 (IL-29)/interferon-λ1 (IFNλ1) were decreased (P < 0.001) and the levels of latency-associated peptide and osteoprotegerin were increased (P = 0.002 and P = 0.001, respectively) in samples of AqH, but not serum, from patients with JIA-associated uveitis. Multivariate analysis correcting for disease activity and treatment revealed that intraocular levels of IL-29/IFNλ1 were specifically decreased in patients with JIA-associated uveitis as compared to those with idiopathic uveitis. Indeed, JIA-associated uveitis patients and idiopathic uveitis patients showed distinct profiles of intraocular soluble mediators. IL-29/IFNλ1 showed a high area under the curve value (0.954), with 23.5 pg/ml as the optimal cutoff value.

CONCLUSION

We identified IL-29/IFNλ1 as an intraocular biomarker for JIA-associated uveitis, which suggests that aberrant IFNλ signaling might be important in JIA-associated uveitis and distinct from other forms of childhood uveitis.

Interleukin-29 Enhances Synovial Inflammation and Cartilage Degradation in Osteoarthritis

We have recently shown that IL-29 was an important proinflammatory cytokine in pathogenesis of rheumatoid arthritis (RA). Inflammation also contributes to the pathogenesis of osteoarthritis (OA). The aim of this study was to investigate the effect and mechanism of IL-29 on cytokine production and cartilage degradation in OA. The mRNA levels of IL-29 and its specific receptor IL-28Ra in peripheral blood mononuclear cells (PBMCs) were significantly increased in OA patients when compared to healthy controls (HC). In the serum, IL-29 protein levels were higher in OA patients than those in HC. Immunohistochemistry revealed that both IL-29 and IL-28Ra were dramatically elevated in OA synovium compared to HC; synovial fibroblasts (FLS) and macrophages were the main IL-29-producing cells in OA synovium. Furthermore, recombinant IL-29 augmented the mRNA expression of IL-1β, IL-6, IL-8, and matrix-metalloproteinase-3 (MMP-3) in OA FLS and increased cartilage degradation when ex vivo OA cartilage explant was coincubated with OA FLS. Finally, in OA FLS, IL-29 dominantly activated MAPK and nuclear factor-κB (NF-κB), but not Jak-STAT and AKT signaling pathway as examined by western blot. In conclusion, IL-29 stimulates inflammation and cartilage degradation by OA FLS, indicating that this cytokine is likely involved in the pathogenesis of OA.

Hypoxia-Inducible Factor (HIF) as a Target for Novel Therapies in Rheumatoid Arthritis

Hypoxia is an important micro-environmental characteristic of rheumatoid arthritis (RA). Hypoxia-inducible factors (HIF) are key transcriptional factors that are highly expressed in RA synovium to regulate the adaptive responses to this hypoxic milieu. Accumulating evidence supports hypoxia and HIFs in regulating a number of important pathophysiological characteristics of RA, including synovial inflammation, angiogenesis, and cartilage destruction. Experimental and clinical data have confirmed the upregulation of both HIF-1α and HIF-2α in RA. This review will focus on the differential expression of HIFs within the synovial joint and its functional behavior in different cell types to regulate RA progression. Potential development of new therapeutic strategies targeting HIF-regulated pathways at sites of disease in RA will also be addressed.

A novel NF-κB/YY1/microRNA-10a regulatory circuit in fibroblast-like synoviocytes regulates inflammation in rheumatoid arthritis

The main etiopathogenesis of rheumatoid arthritis (RA) is overexpressed inflammatory cytokines and tissue injury mediated by persistent NF-κB activation. MicroRNAs widely participate in the regulation of target gene expression and play important roles in various diseases. Here, we explored the mechanisms of microRNAs in RA. We found that microRNA (miR)-10a was downregulated in the fibroblast-like synoviocytes (FLSs) of RA patients compared with osteoarthritis (OA) controls, and this downregulation could be triggered by TNF-α and IL-1β in an NF-κB-dependent manner through promoting the expression of the YingYang 1 (YY1) transcription factor. Downregulated miR-10a could accelerate IκB degradation and NF-κB activation by targeting IRAK4, TAK1 and BTRC. This miR-10a-mediated NF-κB activation then significantly promoted the production of various inflammatory cytokines, including TNF-α, IL-1β, IL-6, IL-8, and MCP-1, and matrix metalloproteinase (MMP)-1 and MMP-13. In addition, transfection of a miR-10a inhibitor accelerated the proliferation and migration of FLSs. Collectively, our data demonstrates the existence of a novel NF-κB/YY1/miR-10a/NF-κB regulatory circuit that promotes the excessive secretion of NF-κB-mediated inflammatory cytokines and the proliferation and migration of RA FLSs. Thus, miR-10a acts as a switch to control this regulatory circuit and may serve as a diagnostic and therapeutic target for RA treatment.

Interleukin-29 induces receptor activator of NF-κB ligand expression in fibroblast-like synoviocytes via MAPK signaling pathways

AIM

We previously reported that interleukin-29 (IL-29) was highly expressed in the blood and synovium of rheumatoid arthritis (RA) patients and contributed to synovial inflammation by induction of proinflammatory cytokine production. Given chronic inflammation can trigger the process of bone erosion, and receptor activator of nuclear factor-κB ligand (RANKL) plays a crucial role in bone erosion of RA, we hypothesize that IL-29 mediates bone erosion in RA by regulation of RANKL expression. Here, we investigated the effect of IL-29 on RANKL expression in RA fibroblast-like synoviocytes (FLS) and the relevant signaling pathways involved in it.

METHODS

Primary fibroblast cells isolated from RA patients were stimulated by recombinant IL-29 in the presence or absence of anti-IL-29 antibody, and the expression levels of RANKL were assessed using real-time polymerase chain reaction and immunostaining. Furthermore, the IL-29 signaling pathway for regulation of RANKL was also examined by Western blotting assay.

RESULTS

IL-29 upregulated RANKL expression in a dose-dependent manner, and blockade of IL-29 resulted in a significantly reduced RANKL expression in RA-FLS. Incubation RA-FLS with IL-29 (100 ng/mL) led to phosphorylation of ERK (extracellular signal-regulated kinase), p38 and JNK (c-Jun N-terminal kinase). The expression of RANKL induced by IL-29 could be completely blocked by the inhibitors of mitogen-activated protein kinase (MAPK) signal pathway, including PD98059 (ERK inhibitor), SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor).

CONCLUSION

These findings indicate, for the first time, that IL-29 could directly induce RANKL expression in RA-FLS via MAPK signaling pathway, suggesting IL-29 might be a new target in the prevention of joint destruction in RA.

IFN-λ is able to augment TLR-mediated activation and subsequent function of primary human B cells

During the past decade, increased emphasis has been placed on finding alternatives to IFN-α-based therapies. One such alternative, IFN-λ, has shown therapeutic promise in a variety of diseases, but research of this family of cytokines has been primarily focused on their antiviral activities. The goal of the present study was to investigate the role of IFN-λ in the regulation and modulation of B cell function. We show that, similar to IFN-α, IFN-λ1 is able to augment TLR-mediated B cell activation, partially attributed to an upregulation of TLR7 expression, and that both naïve and memory B cells express the limiting type III IFN receptor component, IFN-λR1. Furthermore, this IFN-λ-enhanced B cell activation resulted in increased cytokine and Ig production during TLR7 challenge, most prominently after the addition of helper T cell signals. Ultimately, these elevated cytokine and Ig levels could be partially attributed to the increase in proliferation of TLR7-challenged B cells by both type I and type III IFNs. These findings demonstrate the ability of IFN-λ to boost humoral immunity, an important attribute to consider for further studies on immunity to pathogens, vaccine development, and ongoing advancement of therapeutic strategies aimed at replacing IFN-α-based treatments with IFN-λ.

miR-573 is a negative regulator in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by abnormal inflammation, angiogenesis, and cartilage destruction. Our previous study demonstrated an increased expression of thioredoxin domain containing 5 (TXNDC5) in the synovial tissues of RA, and its overexpression was implicated in RA pathology. Although TXNDC5 variation is linked to genetic susceptibility to RA, the regulation of its abnormal expression has not been well defined. Here, we show that TXNDC5 is directly targeted by microRNA (miR)-573, and TXNDC5, in turn, mediates the suppressive effect of miR-573 on the invasion of synovial fibroblasts of RA (RASFs). miR-573 overexpression suppressed the expression of interleukin 6 (IL-6) and cyclooxygenase 2 in RASFs, as well as the production of tumor necrosis factor-alpha and interleukin-1 beta by activated THP-1 cells in response to lipopolysaccharide (LPS) stimulation. Moreover, treatment with conditioned medium of RASFs transfected with miR-573 mimic inhibited the angiogenic ability of human umbilical vein endothelial cells (HUVECs). Of note, epidermal growth factor receptor and Toll-like receptor 2 were validated as new direct targets of miR-573, and mediate the regulation of miR-573 on IL-6 production as well as the angiogenesis of HUVECs. In addition, exogenous miR-573 expression suppressed the activation of mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3, and phosphatidylinositol-3 kinase/activate protein kinase B in RASFs in response to LPS. Indeed, MAPK signaling was essential to ensure the function of miR-573. Taken together, our study points toward the protective roles of miR-573 in the pathological process of RA and suggests a potential target in the treatment of RA.