Pro-inflammatory effects of interleukin-35 in rheumatoid arthritis

The dichotomic role of single cytokines: Fine-tuning immune responses

Cytokines are known for their pleiotropic effects. They can be classified by their function as pro-inflammatory, such as tumor necrosis factor (TNF), interleukin (IL) 1 and IL-12, or anti-inflammatory, like IL-10, IL-35 and transforming growth factor β (TGF-β). Though this type of classification is an important simplification for the understanding of the general cytokine's role, it can be misleading. Here, we discuss recent studies that show a dichotomic role of the so-called pro and anti-inflammatory cytokines, highlighting that their function can be dependent on the microenvironment and their concentrations. Furthermore, we discuss how the back-and-forth interplay between cytokines and immunometabolism can influence the dichotomic role of inflammatory responses as an important target to complement cytokine-based therapies.

Epstein-Barr virus-induced gene 3 commits human mesenchymal stem cells to differentiate into chondrocytes via endoplasmic reticulum stress sensor

Mesenchymal stem cells (MSC) can differentiate into chondrocytes. Epstein-Barr virus-induced gene 3 (EBI3) is differentially expressed during chondrogenic differentiation and can be produced by MSC. EBI3 is also a subunit of interleukin (IL)-27 and IL-35, and it accumulates in the endoplasmic reticulum (ER) when its partners, such as IL-27 p28 and IL-35 p35, are insufficient. ER stress induced by protein accumulation is responsible for chondrogenic differentiation. However, the role of EBI3 and its relevance to the ER stress in chondrogenic differentiation of MSC have never been addressed. Here, we demonstrate that EBI3 protein is expressed in the early stage of chondrogenic differentiation of MSC. Additionally, knockdown, overexpression, or induction of EBI3 through IL-1β inhibits chondrogenesis. We show that EBI3 localizes and accumulates in the ER of MSC after overexpression or induction by IL-1β and TNF-α, whereas ER stress inhibitor 4-phenylbutyric acid decreases its accumulation in MSC. Moreover, EBI3 modulates ER stress sensor inositol-requiring enzyme 1 α (IRE1α) after induced by IL-1β, and MSC-like cells coexpress EBI3 and IRE1α in rheumatoid arthritis (RA) synovial tissue. Altogether, these data demonstrate that intracellular EBI3 commits to chondrogenic differentiation by regulating ER stress sensor IRE1α.

miR-10 and Its Negative Correlation with Serum IL-35 Concentration and Positive Correlation with STAT5a Expression in Patients with Rheumatoid Arthritis

Circulating free-cell miRNAs are increasingly important as potential non-invasive biomarkers due to the easy accessibility of clinical materials. Moreover, their epigenetic role may provide insight into the mechanisms of pathogenesis. Nevertheless, these aspects are mostly studied in the area of oncological diseases. Therefore, this research aimed to find the potential association of selected miRNAs in serum with the expression of Th17/Treg transcription factors and clinical features in RA patients. Accordingly, experiments was conducted on rheumatoid arthritis (RA), osteoarthritis (OA) and healthy subjects (HC). Analysis of miRNAs level in serum was performed using LNA miRNA PCR assays. mir-10 was detected only in RA patients. Furthermore, its expression was correlated with IL-35 serum concentration and the mRNA level of STAT5a in whole blood in RA. Additionally, a tendency of the raised level of miR-10 was noted in RA patients with high activity disease. miR-326 was significantly upregulated in RA patients with rheumatoid factor presence. In HC the correlation between miR-26 and IL-21 serum levels and expression of SMAD3 have been found. In OA patients, correlations between miR-126 and HIF1 expression and between miR-146 and RORc have been noted. The differential association of transcription factor expression with serum miRNA levels may be important in the diagnosis and progression of RA and OA.

Histopathology of Psoriatic Arthritis Synovium—A Narrative Review

Psoriatic arthritis (PsA) is a phenotypically heterogeneous chronic inflammatory disease associated to type I major histocompatibility complex alleles whose complex pathogenesis is still not completely understood. The psoriatic synovium shares general features of chronic inflammation with rheumatoid arthritis (RA) and other arthritis, such as hyperplasia of the intimal lining layer, sublining influx of inflammatory cells and neoangiogenesis, but recognizing disease-specific histopathologic findings may help in diagnosis and definition of therapeutic targets. Available literature reports conflicting data regarding the extension of lining hyperplasia, that does not allow depiction from RA. Sublining inflammatory cells consist of T and B cells and macrophages, plasma cells, mast cells and follicular dendritic cells, with a higher amount of overall T, mast cell and IL-17 producing CD8+ T lymphocytes and lower proportion of plasma cells when compared to the rheumatoid synovium. The amount of synovium IL17+ CD8+ T cells correlates positively to measures of disease activity. Lymphoid follicles with characteristics of germinal centers have been identified, similar to the ones described in RA. Neoangiogenesis is more prominent in PsA but can also be an outstanding feature in some RA samples, and different molecules involved in the process appear to have different influence in each disease. IL-17 and IL-22 expression in the synovium does not allow depiction between diseases. Among other cytokines and molecules likely implicated in disease physiopathology, only IL-35 is demonstrated to be reduced in PsA when compared to RA.

Interleukin-35: Structure, Function and Its Impact on Immune-Related Diseases

The balance between inflammatory and anti-inflammatory immune responses is maintained through immunoregulatory cell populations and immunosuppressive cytokines. Interleukin-35 (IL-35), an inhibitory cytokine that belongs to the IL-12 family, is capable of potently suppressing T cell proliferation and inducing IL-35-producing induced regulatory T cells (iTr35) to limit inflammatory responses. Over the past decade, a growing number of studies have indicated that IL-35 plays an important role in controlling immune-related disorders, including autoimmune diseases, infectious diseases, and cancer. In this review, we summarize the current knowledge about the biology of IL-35 and its contribution in different diseases, and we discuss the potential of and barriers to harnessing IL-35 as a clinical biomarker or immunotherapy.

Value of Contrast-Enhanced Ultrasonography in Evaluating Rheumatoid Arthritis: Preliminary Research Based on an Animal Model

BACKGROUND The aim of this study was to evaluate the effectiveness of grayscale ultrasound (GSUS), power Doppler imaging (PDI), and contrast-enhanced ultrasonography (CEUS) in early rheumatoid arthritis (RA) diagnosis through animal experiments. MATERIAL AND METHODS A rabbit RA model was constructed. The animals were randomly divided into 2 groups, namely, the RA model group and the control group. GSUS, PDI, and CEUS were performed in the model group during early RA and were compared with pathology of synovial biopsies. The consistency of 3 types of ultrasonography was evaluated in tandem with pathological grading. RESULTS 23 rabbits in the RA model group completed the experiment. GSUS showed that the synovial thickening of grades 1, 2 and 3 occurred in 12, 19, and 15 joints, respectively. The sensitivity, specificity, and accuracy of PDI in the diagnosis of knee joint synovitis in RA grades 1, 2, and 3 were 80.56% (29/36), 60.00% (6/10), and 76.09% (35/46), respectively, while those with CEUS were 94.44% (34/36), 90.00% (9/10), and 93.47% (43/46), respectively. The differences in diagnostic sensitivity, specificity, and accuracy of the 2 methods were statistically significant. Additionally, the thickness of the synovium measured with GSUS precontrast was greater than that of postcontrast. CONCLUSIONS RA evaluated with GSUS is often more hypertrophied than when evaluated with CEUS, while evaluation by PDI is less hypertrophied than that by CEUS. However, from a practical view point, GSUS and PDI are of sufficient practical value, except for in a few special cases.

CD3+CD4+gp130+ T Cells Are Associated With Worse Disease Activity in Systemic Lupus Erythematosus Patients

The receptors for IL-35, IL-12Rβ2 and gp130, have been implicated in the inflammatory pathophysiology of autoimmune diseases. In this study, we set out to investigate the serum IL-35 levels and the surface levels of IL-12Rβ2 and gp130 in CD3⁺CD4⁺, CD3⁺CD4^─ and CD3^─CD4^─ lymphocyte subpopulations in systemic lupus erythematosus (SLE) patients (n=50) versus healthy controls (n=50). The potential T cell subsets associated with gp130 transcript (i.e. IL6ST) expression in CD4⁺ T cells of SLE patients was also examined in publicly-available gene expression profiling (GEP) datasets. Here, we report that serum IL-35 levels were significantly higher in SLE patients than healthy controls (p=0.038) but it was not associated with SLEDAI-2K scores. The proportions of IL-12Rβ2⁺ and gp130⁺ cells in SLE patients did not differ significantly with those of healthy controls in all lymphocyte subpopulations investigated. Essentially, higher SLEDAI-2K scores were positively correlated with increased proportion of gp130⁺ cells, but not IL-12Rβ2⁺ cells, on CD3⁺CD4⁺ T cells (r=0.425, p=0.002, q=0.016). Gene Set Enrichment Analysis (GSEA) of a GEP dataset of CD4⁺ T cells isolated from SLE patients (n=8; GSE4588) showed that IL6ST expression was positively associated with genes upregulated in CD4⁺ T cells vs myeloid or B cells (q<0.001). In an independent GEP dataset of CD4⁺ T cells isolated from SLE patients (n=9; GSE1057), IL6ST expression was induced upon anti-CD3 stimulation, and that Treg, T_CM and CCR7⁺ T cells gene sets were significantly enriched (q<0.05) by genes highly correlated with IL6ST expression (n=92 genes; r>0.75 with IL6ST expression) upon anti-CD3 stimulation in these SLE patients. In conclusion, gp130 signaling in CD3⁺CD4⁺ T cell subsets may contribute to increased disease activity in SLE patients, and it represents a promising therapeutic target for inhibition in the disease.

Pathogenesis and Function of Interleukin-35 in Rheumatoid Arthritis

It is well known that RA (Rheumatoid arthritis) is an autoimmune disease characterized by multiple and symmetric arthropathy. The main pathological features of RA are synovial hyperplasia, angiogenesis, pannus formation, inflammatory cell infiltration, articular cartilage, bone destruction, and ultimately joint dysfunction, even deformity. IL-35 (Interleukin-35) is a new member of the IL-12 (Interleukin-12) family, which is an immunosuppressive and anti-inflammatory cytokine secreted mainly by Treg (T regulatory cells). There is evidence suggested that IL-35 can attenuate the progression of RA through influencing the immune and pathological process. It suggests that IL-35 played an important role in the pathogenesis of RA, and can be used as a potential target for the future treatment of RA. This review summarizes the recent advances of IL-35 in the pathological roles and the therapeutic potential roles in RA.

Vitamin D as a Key Player in Modulating Rheumatoid Arthritis-derived Immune Response

Rheumatoid arthritis (RA) is a systemic inflammatory disease with chronic nature of joints related to autoimmunity. Vitamin D was found to modulate cell growth, function of immune cells and anti-inflammatory action. The aims of that study were to investigate serum level of vitamin D and some cytokines and to identify the correlation between vitamin D and these cytokines in RA. Totally 40 RA patients without vitamin D supplement were involved in this study. Serum level of vitamin D, interleukin-6 (IL-6), IL-10, IL-35, C-reactive protein (CRP) and tumor necrosis factor α (TNF-α), all of them were measure in all patients by enzyme-linked immunosorbent assay (ELISA). Patients were classified according to Vitamin D levels into two groups; RA patients with Vit. D deficiency (n=25) and RA patients with Vit. D sufficiency (n=15). IL-6 was lower significantly (P = 0.03) in RA patients with Vit. D sufficiency than RA patients with Vit. D deficiency. IL-10 and IL-35 were higher significantly (P = 0.0234, P = 0.0356 respectively) in RA patients with Vit. D sufficiency than RA patients with Vit. D deficiency. Vit. D was significantly positively correlated with both IL-10 (r = 0.4516, P = 0.0034) and IL-35 (r = 0.3424, P = 0.0329) and negatively correlated with IL-6 (r = -0.3188, P = 0.0479). Sufficient serum level of Vit. D is correlated with higher level of anti-inflammatory cytokines (IL-10 and IL-35) and lower level of IL-6. This support the immunomodulatory effect of Vit. D in RA.

Association of IL-35 expression and gene polymorphisms in rheumatoid arthritis

Interleukin (IL)-35 is the newest member of the IL-12 family. It is expressed in many immune cells and has been recognized as a novel inflammatory cytokine that may have bifunctional properties. Recent findings have indicated that the expression of IL-35 is abnormal in rheumatoid arthritis (RA) patients. However, the results were inconsistent. In this study, 400 RA patients were recruited to evaluate serum levels of IL-35 in a Chinese Han population by enzyme-linked immunosorbent assay. The association of IL-35 gene polymorphisms and RA genetic susceptibility was investigated in 400 RA patients and 612 healthy controls. The results showed that serum levels of IL-35 were elevated in 100 RA patients compared to 51 healthy controls, relating to disease activity and synovial fluid IL-35 expression in the training cohort. Another independent 300 RA patients and 369 other rheumatic disease patients (98 lupus, 95 osteoarthritis, 95 gout, 42 Sjogren's syndrome and 39 ankylosing spondylitis patients) confirmed that serum levels of IL-35 were elevated in RA patients, and serum IL-35 has good diagnostic ability for differentiating RA from the other rheumatic diseases. The genotyping of 10 IL-35 polymorphisms, including rs2227314, rs2243115, rs2243123, rs2243131, rs568408, rs583911, rs428253, rs4740, rs9807813 and rs4905, revealed that rs2227314, rs2243131, rs9807813, and rs583911 were correlated with RA risk. Different genotypes (rs2227314, rs583911, and rs9807813) exhibited different expression of IL-35. These findings demonstrate that serum levels of IL-35 are increased in RA patients and that IL-35 polymorphisms are correlated with RA risk.

Interleukin-35 in idiopathic inflammatory myopathies

BACKGROUND

Interleukin-35 (IL-35) is a recently described heterodimeric cytokine that belongs to the IL-12 family and consists of p35 (IL-12a) and EBI3 (IL-27b) subunits. The expression of IL-35 in humans is inducible in response to inflammatory stimuli. Increased IL-35 levels were documented in several autoimmune inflammatory diseases, suggesting a possible immunomodulatory role in their pathogenesis.

OBJECTIVES

The aim of this study was to explore a potential role of IL-35 in the pathogenesis of idiopathic inflammatory myopathies (IIM) by studying the expression of IL-35 subunits in muscle biopsy samples and by evaluating serum levels of IL-35 and their association with disease activity in IIM patients.

METHODS

The expression of IL-35 subunits was studied in serial sections of 9 muscle biopsy samples [4 polymyositis (PM), 5 dermatomyositis (DM)] and in 7 non-inflammatory control muscle biopsies. Serum levels of IL-35 were measured in 23 PM, 28 DM and 15 cancer associated myositis (CAM) patients as well as in 40 healthy controls. Disease activity was evaluated using the Myositis Disease Activity Assessment Tool (MDAAT) and by serum muscle enzymes.

RESULTS

Expression of both IL-35 subunits was evident in the inflammatory infiltrates in IIM muscle biopsies, while no IL-35 expression was observed in control muscle samples. IL-35 serum levels were increased in all IIM patients compared to healthy controls [median 119.5 (range 32.1-1074.5) vs 36.2 (range 1.5-86.5) pg/ml, P < 0.001]. There were no differences in IL-35 serum levels between myositis subgroups (DM, PM or CAM). Serum IL-35 levels correlated significantly with physician's assessment of global (r = 0.29, p = 0.021), muscle (r = 0.30, p = 0.017) and extramuscular (r = 0.30, p = 0.016) disease activity as well as creatine kinase (r = 0.26, p = 0.044) and lactate dehydrogenase (r = 0.40, p = 0.003) levels. There was a significant correlation with pulmonary activity in patients with interstitial lung disease (r = 0.39, p = 0.037). Serum IL-35 correlated negatively with duration of treatment (r = -34, p = 0.009).

CONCLUSIONS

IL-35 is overexpressed in inflammatory infiltrates in muscle tissue and serum in IIM patients and there is correlation with several disease activity parameters. These data suggest potential role of locally produced IL-35 in the pathogenesis of inflammatory myopathies.

Interleukin-35 regulates the balance of Th17 and Treg responses during the pathogenesis of connective tissue diseases

Interleukin (IL)-35 belongs to the IL-12 cytokine family and is a heterodimer of the p35 and Epstein-Barr virus-induced gene 3 (EBI3) subunits. Functionally, IL-35 can promote the proliferation and activation of regulatory T cells (Tregs) and suppress the function of T helper 17 (Th17) cells and other inflammatory cells to inhibit immune responses. In recent years, an abnormal IL-35 expression causing a Th17/Treg imbalance has been associated with the development and progression of several connective tissue diseases (CTDs), such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), and primary Sjögren's syndrome (pSS). Here, we review the role of IL-35 in regulating the balance of Th17/Treg responses in different types of CTDs and provide new insights into the role of IL-35 in these diseases.

Different expression levels of interleukin-35 in asthma phenotypes

Background

Interleukin (IL)-35 is a newly discovered inhibitory cytokine which is produced by regulatory B and T lymphocytes and belongs to the IL-12 family. It plays a suppressive role in human inflammatory diseases; however, its role in asthma phenotypes is unclear. Our study focuses on the sputum IL-35 level in patients and investigates different airway inflammation capacities of sputum IL-35 in patients with different asthma phenotypes.

Objective

We aimed to determine the sputum IL-35 levels in asthmatic patients with clinical remission phenotypes and control subjects and to investigate possible correlations among lung function, age, sex, fractional exhaled nitric oxide (FeNO), and smoking history in these phenotypes.

Methods

Sputum samples were collected from patients with clinical asthma remission (n = 89, 37 males, age 52.24 ± 13.32 years) and a healthy control group (n = 19, 9 males, age 44.58 ± 16.3 years). All subjects underwent sputum induction. Induced sputum was assessed for inflammatory cell count, and sputum levels of IL-35 and other cytokines were measured by ELISA and Cytometric Bead Array, respectively.

Results

Sputum IL-35 (median (q1, q3)) levels showed no significant difference between asthma patients (4.89 ng/mL (2.97, 22.75)) and healthy controls (6.01 ng/mL (4.09, 30.47)). However, the sputum IL-35 level was significantly reduced in patients with eosinophilic asthma (EA) (3.95 ng/mL (2.80, 11.00)) compared to patients with neutrophilic asthma (NA) (40.59 ng/mL (20.59, 65.06), p = 0.002), paucigranulocytic asthma (PA) (6.25 ng/mL (3.10, 24.60), p = 0.012), and mixed granulocytic asthma (MA) (22.54 ng/mL (2.58, 52.45), p = 0.026). IL-35 levels in sputum showed a positive correlation with sputum neutrophil cells and a negative correlation with FeNO, FEV1% predicted, and FVC predicted. Furthermore, sputum IL-35 had a significant positive association with Th1-related factors and a negative correlation with Th2-related factors.

Conclusions

Sputum IL-35 is likely involved in different pathophysiological mechanisms of NA and EA and exerts different effects in asthma phenotypes.

Neuraxial Cytokines in Pain States

A high-intensity potentially tissue-injuring stimulus generates a homotopic response to escape the stimulus and is associated with an affective phenotype considered to represent pain. In the face of tissue or nerve injury, the afferent encoding systems display robust changes in the input–output function, leading to an ongoing sensation reported as painful and sensitization of the nociceptors such that an enhanced pain state is reported for a given somatic or visceral stimulus. Our understanding of the mechanisms underlying this non-linear processing of nociceptive stimuli has led to our appreciation of the role played by the functional interactions of neural and immune signaling systems in pain phenotypes. In pathological states, neural systems interact with the immune system through the actions of a variety of soluble mediators, including cytokines. Cytokines are recognized as important mediators of inflammatory and neuropathic pain, supporting system sensitization and the development of a persistent pathologic pain. Cytokines can induce a facilitation of nociceptive processing at all levels of the neuraxis including supraspinal centers where nociceptive input evokes an affective component of the pain state. We review here several key proinflammatory and anti-inflammatory cytokines/chemokines and explore their underlying actions at four levels of neuronal organization: (1) peripheral nociceptor termini; (2) dorsal root ganglia; (3) spinal cord; and (4) supraspinal areas. Thus, current thinking suggests that cytokines by this action throughout the neuraxis play key roles in the induction of pain and the maintenance of the facilitated states of pain behavior generated by tissue injury/inflammation and nerve injury.

A bibliometric analysis of IL-35 research from 2009 to 2018

Background

Interleukin-35 (IL-35) is a recently discovered cytokine that plays a role in immune suppression and has therefore been the subject of a great deal of research. A bibliometric analysis of the global research concerning IL-35, however, is rare.

Objectives

The aim of this research was to assess the international scientific output of IL-35 research and explore its hotspots and frontiers from 2009 to 2018 by bibliometric analysis.

Methods

Publications about IL-35 research from 2009 to 2018 were retrieved from the Web of Science Core Collection (WoSCC). Citespace V was used to analyze years, journals, countries, research institutions, areas of exploration, research hotspots, and trends of publication.

Results

We retrieved a total of 416 publications and observed a trend of publications increasing over the past decade. Original articles (351) were the most frequently occurring document type. The largest number of publications belonging to one country and one institution, respectively, was China (202) and Tianjin Medical University (17). Trending keywords may indicate frontier topics, including "infectious tolerance," "autoimmune," and "central nervous system."

Conclusion

This study provides valuable information on the study of IL-35 so that researchers may identify new research fields.

Elevated serum IL-35 levels in rheumatoid arthritis are associated with disease activity

To investigate serum interleukin (IL)- 35 levels in patients with rheumatoid arthritis (RA) and to describe the association between serum IL-35 levels and clinical parameters: erythrocyte sedimentation rate (ESR), C reactive protein (CRP), global health on Visual Analog Scale, Disease Activity Score in 28 joints based on ESR (DAS28-ESR), rheumatoid factor (RF) and anticyclic citrullinated peptide antibodies (ACPAs). The study included 129 patients with RA and 83 healthy controls. Serum IL-35 levels were detected by ELISA. ESR and CRP were measured by the Westergren method and the immune transmission turbidity method, respectively. RF and ACPA were measured using immunoturbidimetric assays and chemiluminescence analysis, respectively. The results showed that serum IL-35 levels were elevated in patients with RA. Univariate and multivariate analyses showed that the high serum IL-35 levels were correlated with low ESR and DAS28-ESR. These suggested that IL-35, an important anti-inflammatory cytokine, may participate in the regulation of the pathogenesis of RA, especially with disease activity.

Association between IL-35 and coronary arterial lesions in children with Kawasaki disease

Kawasaki disease (KD) arises due to the acute inflammation and immune system dysfunction. This study investigated the relationship between the serum level of IL-35 and coronary artery lesions (CALs) in patients with KD. We obtained blood samples from 90 children with KD before intravenous immunoglobulin therapy. Levels of IL-35, IL-6, IL-17A, IL-10, MCP-1 and VEGF were measured in 190 cases, including 4 groups: KD with coronary arterial lesions (n = 46), KD without coronary arteries lesions (n = 44), febrile control group (FC, n = 40) and the normal control group (NC, n = 60). White blood cell counts (WBC), red blood cell counts (RBC), hemoglobin, platelet, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and procalcitonin were tested in all subjects. Levels of IL-35, RBC and hemoglobin significantly decreased, and IL-6, IL-17A, IL-10, MCP-1 and VEGF were significantly elevated in the KD group compared with febrile and control groups. IL-35 serum level even decreased, and ESR, IL-6, MCP-1 and VEGF increased in the KD patients with CALs. Serum levels of IL-35 in KD patients were negatively associated with WBC, CRP, IL-6, IL-17A, IL-10, MCP-1 and VEGF in children with KD. IL-35 may have the effect on inhibiting inflammatory process in KD and further preventing KD patients from coronary artery lesion.

IL-35 inhibits human osteoclastogenesis from monocytes induced by receptor-activator of NF-κB ligand

IL-35 is known as a regulatory cytokine produced by regulatory T cells. It has also been reported that IL-35 suppresses the proliferation of Th17 cells, which is involved in the pathogenesis of many autoimmune diseases. However, in rheumatoid arthritis patients, the role of IL-35 is controversial, and the role of IL-35 in bone metabolism has not been clarified. We investigated the effect of IL-35 on human osteoclast differentiation and activation. We first evaluated the effect of rhIL-35 on human osteoclastogenesis from monocytes cultured alone, induced by soluble-RANKL. We also examined the role of IL-35 on the bone-resorption function of mature osteoclasts. Furthermore, we analysed the molecular mechanism of IL-35 function in monocytes or pre-osteoclasts using RT-PCR. rhIL-35 significantly inhibited human osteoclastogenesis in a dose-dependent manner. In addition, rhIL-35 also significantly decreased the area of pit formation by mature osteoclasts. rhIL-35 significantly decreased mRNA expression of RANK in monocytes and RANK and FOS in pre-osteoclasts. Our current findings suggest that IL-35 inhibits osteoclastogenesis and osteoclast activation by inhibiting both RANK and FOS. IL-35 also has an inhibitory effect on osteoclastic-bone resorption, suggesting that IL-35 may have a therapeutic potential for RA.

Mesenchymal stem cell expression of interleukin-35 protects against ulcerative colitis by suppressing mucosal immune responses

BACKGROUND

Interleukin-35 (IL-35) has recently been identified as an immunosuppressive cytokine that has been used as a potential therapy for chronic inflammatory and autoimmune diseases. However, there remains a paucity of data regarding its potential benefits after integration into mesenchymal stem cells (MSCs).

METHODS

We used a dextran sulfate sodium (DSS)-induced colitis mice model and treated them with IL-35-MSCs, MSCs or saline. The body weight was recorded daily and inflammatory processes were determined. Cytokine secretion by lamina propria lymphocytes (LPLs) and percentage of regulatory T cells (Tregs) were also measured.

RESULTS

The data showed that mice in the two treated groups recovered their body weight more rapidly than mice treated with saline in the later stage of colitis. The colon lengths of IL-35-MSC-treated mice were markedly longer than those in the other two groups and the inflammation reduced significantly. Furthermore, the percentage of Foxp3 + Tregs increased significantly and the level of proinflammatory cytokines produced by LPLs decreased significantly in the IL-35-MSC-treated group.

DISCUSSION

The results demonstrate that IL-35-MSCs could ameliorate ulcerative colitis by down-regulating the expression of pro-inflammatory cytokines.

Clinical Significance of Decreased Interleukin-35 Expression in Patients with Psoriasis

In psoriasis, a chronic, recurrent, inflammatory skin disease, CD4+T cells and their related cytokines play an important role in its pathogenesis. The role of interleukin (IL)-35, an immunosuppressive cytokine involved in many autoimmune diseases, is unclear in the pathogenesis of psoriasis. This study evaluated IL-35 expression and clinical significance in psoriasis. Protein and mRNA levels of specified markers were measured by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR), respectively. Results showed that plasma IL-35 concentrations were lower in patients with psoriasis than in healthy individuals (Z = -6.525, P < .0001). Ebi3 and p35 showed lower mRNA levels in peripheral blood mononuclear cells from patients with psoriasis than in healthy individuals (Z = -5.078, P < .0001, Z = -2.609, P = .009, respectively). The areas under the receiver-operating characteristic (ROC) curves of IL-35, Ebi3, and p35 for patients with psoriasis versus the control were 0.86, 0.78, and 0.64, respectively. Pearson correlation analysis showed that plasma IL-35 expression negatively correlated with interferon-gamma, tumor necrosis factor-alpha, levels of IL-23, -17, and -22, or the Psoriasis Activity and Severity Index and positively correlated with levels of transforming growth factor beta and IL-10 levels in patients with psoriasis. Summarily, IL-35 might mediate psoriasis pathogenesis by influencing the expression of Th1/Th17/Treg -related cytokines and might be a putative target in monitoring or treating psoriasis.

Emerging role of IL-35 in inflammatory autoimmune diseases

Interleukin 35 (IL-35) is the recently identified member of the IL-12 family of cytokines and provides the possibility to be a target for new therapies for autoimmune, inflammatory diseases. It is composed of an α chain (p35) and a β chain (EBI3). IL-35 mediates signaling by binding to its receptors, activates subsequent signaling pathways, and therefore, regulates the differentiation, function of T, B cells, macrophages, dendritic cells. Recent findings have shown abnormal expression of IL-35 in inflammatory autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, type 1 diabetes, psoriasis, multiple sclerosis, autoimmune hepatitis, experimental autoimmune uveitis. In addition, functional analysis suggested that IL-35 is critical in the onset and development of these diseases. Therefore, the present study will systematically review what had been occurred regarding IL-35 in inflammatory autoimmune disease. The information collected will help to understand the biologic role of IL-35 in immune cells, and give information about the therapeutic potential of IL-35 in these diseases.

IL-35 induces N2 phenotype of neutrophils to promote tumor growth

IL-35 is an immunosuppressive cytokine and exerts regulatory effects on T cells, B cells, macrophages and dendritic cells. Neutrophils are important innate immune cells that play key roles in tumor development. The effect of IL-35 on neutrophils remains unknown. Here, we report that IL-35 can induce N2 neutrophil polarization (protumor phenotype) by increasing G-CSF and IL-6 production, and promote neutrophil infiltration into tumor microenvironment. The sustained expression of IL-35 could promote chronic inflammation to augment the proangiogenic and immunosuppressive function of neutrophils. IL-35 stimulated macrophages to secrete proinflammatory cytokines IL-1β and IL-6. IL-1β stimulated γδ T cells to produce IL-17, which in turn increased the production of G-CSF. By increasing the expression of G-CSF and IL-6, IL-35 could up-regulate the expression of MMP-9 and Bv8, and down-regulate TRAIL expression in neutrophils, thus augmenting the proangiogenic function of neutrophils. Moreover, G-CSF/IL-6 induced the enhanced activation of STAT3 and ERK pathways in neutrophils, thus increasing the expression of iNOS to suppress T cell activation. Our findings suggest that IL-35 can promote tumor progression by functioning as an up-stream cytokine to promote cancer-associated inflammation and control neutrophil polarization. Targeting IL-35 might be an important approach for designing new strategy of tumor therapy.

Decreased interleukin(IL)-35 Expression is Associated with Active Intraocular Inflammation in Vogt-Koyanagi-Harada (VKH) Disease

Purpose: Recent studies have reported that IL-35 has a protective effect in autoimmune disease. In this study, we explored the role of IL-35 in the pathogenesis of Vogt-Koyanagi-Harada (VKH) disease. Methods: The IL-35/EBI3 and IL-35/P35 mRNA level was assayed by Real-Time PCR. The level of IL-35 in serum was detected by ELISA. PBMCs and monocyte-derived DCs were cultured with or without IL-35 and the concentration of IL-17, IL-10, IFN-γ, IL-6, TNF-α, and IL-1β in supernatants was tested by ELISA. Results: The serum level of IL-35 is reduced in active VKH patients. The mRNA expression of the two subunits IL-35/EBI3 and IL-35/P35 in PBMCs from patients with active VKH was also decreased. IL-35 significantly inhibited IFN-γ and IL-17 expression and induced IL-10 production by PBMCs and inhibited IL-6 production by monocyte-derived DCs. Conclusion: The current study suggests that a decreased IL-35 expression may be involved in the pathogenesis of VKH disease.

Synoviocytes-derived Interleukin 35 Potentiates B Cell Response in Patients with Osteoarthritis and Rheumatoid Arthritis

OBJECTIVE

Elevated expression of interleukin 35 (IL-35) is associated with autoimmune disease, including rheumatoid arthritis (RA). The present study was undertaken to determine the functional interaction among IL-35, B cells, and stromal cells residing in the synovium of patients with RA and osteoarthritis (OA).

METHODS

IL-35 (EBI-3/p35) expression was investigated in RA and OA synovium using quantitative real-time PCR (qRT-PCR) and immunohistochemistry. IL-35 receptor (IL-35R) expression on B cells dissociated from synovium and periphery of patients with RA, OA, and healthy donor controls (HC) was determined by flow cytometry. The degree of B cells activation after IL-4 and/or IL-35 stimulation was measured by flow cytometry and qRT-PCR. Synovial fibroblasts (SF) purified from RA and OA synovium were cocultured with peripheral HC B cells in the presence/absence of tumor necrosis factor-α (TNF-α) and with/without anti-IL-35-blocking antibodies.

RESULTS

EBI-3/p35 transcripts were expressed in close proximity to B cells residing in RA and OA synovium. IL-35R subunits, gp130 and IL-27Rα, but not IL-12Rβ2, were expressed in B cells extracted from the synovium and periphery of patients with RA/OA. Notably, RA synovium expressed the highest level of IL-27Rα on their cell surface. IL-35 induced proliferation and IgG production in HC B cells. Cocultures of HC B cells with RASF, but not OASF, exhibited significantly elevated B cells activation. TNF-α-induced, RASF-dependent secretion of IgG in B cells is partly IL-35-dependent.

CONCLUSION

To our knowledge, for the first time we demonstrated that synovial/peripheral B cells expressed IL-35R and were responsive to IL-35 stimulation. SF residing in RA synovium can be linked to B cell activation and maintenance in RA synovium through IL-35.

Cytokines in the pathogenesis of rheumatoid arthritis: new players and therapeutic targets

In recent years, the landscape of pro- and anti-inflammatory cytokines has rapidly expanded with the identification of new members proven to be involved at different extent in the pathogenesis of chronic immune mediated inflammatory diseases including rheumatoid arthritis (RA). The advance of our understanding of mediators involved in the pathogenesis of RA and in consequence, the development of novel targeted therapies is necessary to provide patients not responding to currently available strategies with novel compounds. The aim of this review article is to provide an overview on recently identified cytokines, emphasizing their pathogenic role and therapeutic potential in RA. A systematic literature review was performed to retrieve articles related to every cytokine discussed in the review. In some cases, evidence from animal models and RA patients is already consistent to move forward into drug development. In others, conflicting observation and the paucity of data require further investigations.Forty years after the discovery of IL-1, the landscape of cytokines is continuously expanding with increasing possibilities to develop novel therapeutic strategies in RA.

Interleukin-35 Suppresses Antiviral Immune Response in Chronic Hepatitis B Virus Infection

The mechanisms of hepatitis B virus (HBV) persistent infection are not completely understood. Interleukin (IL)-35, which is a newly identified cytokine belongs to IL-12 family, has been demonstrated to induce immunotolerance. Thus, the aim of current study was to investigate the role of IL-35 during chronic HBV infection. A total of 61 patients with chronic HBV infection [37 chronic hepatitis B (CHB) and 24 asymptomatic HBV carriers (ASC)] and 20 healthy individuals were enrolled. IL-35 concentration as well as the modulatory function of IL-35 on CD4⁺CD25⁺CD127^dim/− regulatory T cells (Tregs) and on HBV antigen-specific CD8⁺ T cells was investigated. IL-35 expression was significantly increased in both CHB and ASC, and was positively correlated with the levels of HBV DNA. Inhibition of viral replication induced the reduction in serum levels of IL-35. IL-35 stimulation led to inhibition of proinflammatory cytokine productions and elevation of apoptosis in peripheral blood mononuclear cells (PBMCs), but not in HepG2.2.15 cells. Moreover, IL-35 stimulation not only robustly inhibited cellular proliferation, but also up-regulated the production of IL-10 and IL-35 in a HBV antigen-specific and non-specific manner in Tregs/CD4⁺CD25⁻ T cells coculture system, which indicated enhancement of suppressive function of Tregs. Furthermore, IL-35 also reduced both cytolytic activity (direct lysis of HepG2.2.15 cells) and noncytolytic function (IFN-γ and TNF-α production) of HBV antigen-specific CD8⁺ T cells. The current data suggested that IL-35 contributed to maintain viral persistence by suppressing antiviral immune responses and reducing inflammatory responses in chronic HBV infection.

An immunosuppressive function of interleukin-35 in chronic hepatitis C virus infection

Interleukin (IL)-35, a newly identified member of the IL-12 cytokine family, has been reported to suppress inflammation and induce immunotolerance. However, little is known regarding the role of IL-35 during chronic hepatitis C virus (HCV) infection. Herein, we measured the serum IL-35 concentration of 73 patients with hepatitis C and 22 healthy individuals, as well as further investigated the modulatory function of IL-35 on CD4⁺CD25⁺CD127^dim/- regulatory T cells (Tregs) and on hepatocytes infected with HCV in cell culture (HCVcc). IL-35 expression was significantly increased in patients with chronic hepatitis C and was positively correlated with the levels of HCV RNA. Inhibition of viral replication led to decreases in the serum levels of IL-35. IL-35 stimulation not only elevated the percentage of Tregs but also robustly inhibited cellular proliferation and up-regulated the production of anti-inflammatory cytokines (e.g., IL-10 and IL-35) in a HCV-specific and non-specific manner, which indicates enhancement of the suppressive function of Tregs. Although IL-35 did not exert anti-HCV activity in HCVcc-infected Huh7.5 cells, it reduced inflammatory cytokine secretion from Huh7.5 cells. This was probably via inhibition of the STAT1 and STAT3 signaling pathways, which could suppress subsequent liver damage due to chronic hepatitis C. The current data suggested that IL-35 contributes to persistent HCV infection by inhibiting antiviral immune activity. Moreover, IL-35 might also protect against HCV-induced liver injury by down-regulating the expression of proinflammatory cytokines. Thus, the immunosuppressive properties of IL-35 might play contradictory roles in maintaining viral persistence and reducing the inflammatory responses in chronic HCV infection.

β-cell-specific IL-35 therapy suppresses ongoing autoimmune diabetes in NOD mice

IL-35 is a recently identified cytokine exhibiting potent immunosuppressive properties. The therapeutic potential and effects of IL-35 on pathogenic T effector cells (Teff) and Foxp3⁺ Treg, however, are ill defined. We tested the capacity of IL-35 to suppress ongoing autoimmunity in NOD mice. For this purpose, an adeno-associated virus vector in which IL-35 transgene expression is selectively targeted to β cells via an insulin promoter (AAV8mIP-IL35) was used. AAV8mIP-IL35 vaccination of NOD mice at a late preclinical stage of type 1 diabetes (T1D) suppressed β-cell autoimmunity and prevented diabetes onset. Numbers of islet-resident conventional CD4⁺ and CD8⁺ T cells, and DCs were reduced within 4 weeks of AAV8mIP-IL35 treatment. The diminished islet T-cell pool correlated with suppressed proliferation, and a decreased frequency of IFN-γ-expressing Teff. Ectopic IL-35 also reduced islet Foxp3⁺ Treg numbers and proliferation, and protection was independent of induction/expansion of adaptive islet immunoregulatory T cells. These findings demonstrate that IL-35-mediated suppression is sufficiently robust to block established β-cell autoimmunity, and support the use of IL-35 to treat T1D and other T-cell-mediated autoimmune diseases.

Effects of an intravitreal injection of interleukin-35-expressing plasmid on pro-inflammatory and anti-inflammatory cytokines

In order to explore the potential effects of interleukin (IL)-35 on IL-10, transforming growth factor-β (TGF-β), interferon-γ (INF)-γ, IL-12 and IL-17, a pcDNA3.1‑IL-35 plasmid was injected into the vitreous cavity of BALB/c mice. Enzyme-linked immunosorbent assay, western blot analysis and quantitative PCR analysis were performed to confirm the successful expression of IL-35. Slit-lamp biomicroscopy, hematoxylin and eosin staining and immunofluorescence were employed to detect the status of eyes, and western blot analysis was performed to examine the expression of corneal graft rejection-related cytokines. There were no abnormalities in the eyes pre-mydriasis or post-mydriasis and no injuries to the cornea or retina following the injection of IL-35-expressing plasmid. An immunofluorescence assay detected the positive expression of IL-35 in corneal epithelial cells from IL-35‑injected mice and negative staining in the control group. Further study revealed that IL-35 enhanced the expression of IL-10 and TGF-β which reached their highest levels at 1 and 2 weeks after injection, respectively (p<0.01). Moreover, the expression of INF-γ and IL-12 was decreased significantly at 2 weeks after the injection of IL-35-expressing plasmid (p<0.05), and the expression of IL-17 was suppressed notably at 4 weeks after the injection (p<0.05). The intravitreal injection of IL-35-expressing plasmid in mice downregulates the expression of pro-inflammatory cytokines and upregulates the expression of anti-inflammatory cytokines. Thus, IL-35 may further be assessed as a potential target for the treatment of corneal graft rejection.

Interleukin-35 (IL-35) inhibits proliferation and promotes apoptosis of fibroblast-like synoviocytes isolated from mice with collagen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory disorder of the joints that affects 0.5-1 % of adults. Excessive growth of the fibroblast-like synoviocytes (FLS) promotes hyperplasia of synovial tissues and causes its invasion into the bone and cartilage, which eventually causes deformity and dysfunction of affected joints. Interleukin 35 (IL-35) was shown to suppress the inflammatory responses to collagen-induced arthritis (CIA) via upregulation of T regulatory cells and suppression of T helper type 17 cells in a mouse model. To study the effects of IL-35 on the proliferation and apoptosis frequency of cultured FLS isolated from mice with CIA as well as to examine the effects of IL-35 on CIA in vivo. Thirty DBA/1 J mice, which are used as an animal model for RA, were divided randomly (ten mice per group) to a CIA group (collagen treatment), a CIA + IL-35 group (collagen and IL-35 treatments), and a control group (no treatment). Starting on the 24th day after collagen administration, IL-35 was injected intraperitoneally into mice of the CIA + IL-35 group once per day for 10 days. An arthritis index was calculated, and pathological analysis of synovial tissue was performed. FLS isolated from CIA mice were treated with various concentrations of IL-35 (12.5-100 ng/ml). The MTT assay was used to examine FLS proliferation, and apoptosis frequency of FLS was detected by flow cytometry. On day 24, the CIA mice began to exhibit arthritis symptoms, and the symptoms rapidly progressed with time. Treatment with IL-35 significantly alleviated arthritis symptoms and reduced the synovial tissue inflammation. In addition, IL-35 treatment inhibited proliferation and promoted apoptosis in cultured FLS from CIA mice in a dose-dependent manner. IL-35 could ameliorate the symptoms of arthritis in the CIA mouse model in vivo and inhibited FLS proliferation while promoting FLS apoptosis in vitro, thereby exhibited the potential in inhibiting the progression of RA.

Serum Levels of Copper and Zinc in Patients with Rheumatoid Arthritis: a Meta-analysis

Many publications with conflicting results have evaluated serum levels of copper (Cu) and zinc (Zn) in patients with rheumatoid arthritis (RA). To derive a more precise estimation of the relationship, a meta-analysis was conducted. Relevant published data were retrieved through PubMed, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biomedical Database (CBM) before September 20, 2014. Weighted mean difference (WMD) with a 95 % confidence interval (95 % CI) was calculated using STATA 11.0. A total of 26 studies, including 1444 RA cases and 1241 healthy controls, were collected in this meta-analysis. Pooled analysis found that patients with RA had a higher serum level of Cu and a lower serum Zn level than the healthy controls (Cu (μg/dl), WMD = 31.824, 95 % CI = 20.334, 43.314; Zn (μg/dl), WMD = -12.683, 95 % CI = -19.783, -5.584). Subgroup analysis showed that ethnicity had influence on the serum level of Cu (μg/dl) (Caucasian, WMD = 43.907, 95 % CI = 35.090, 52.723, P < 0.001; Asian, WMD = 14.545, 95 % CI = -12.365, 41.455, P = 0.289) and Zn (μg/dl) (Caucasian, WMD = -11.038, 95 % CI = -23.420, 1.344, P = 0.081; Asian, WMD = -14.179, 95 % CI = -18.963, -9.394, P < 0.001) in RA and healthy controls. No evidence of publication bias was observed. This meta-analysis suggests that increased serum level of Cu and decreased serum level of Zn are generally present in RA patients.

Interleukin-35 is upregulated in systemic sclerosis and its serum levels are associated with early disease

OBJECTIVES

IL-35 is a member of the IL-12 family consisting of p35/IL-12a and EBI3/IL-27b subunits. IL-35 exerts immunomodulatory activities in experimental and human autoimmune inflammatory conditions. Our aim was to assess IL-35 expression in the skin and circulation of SSc patients and to characterize its potential association with SSc-related features.

METHODS

Expression of IL-35 in skin and dermal fibroblasts was quantified by quantitative PCR, immunohistochemistry and immunofluorescence. Serum levels of IL-35 (by ELISA), CRP (by turbidimetry), ANA (by immunofluorescence) and autoantibodies of the ENA complex (by immunoblot) were measured in 40 SSc patients. Serum IL-35 was determined in 40 age- and sex-matched healthy controls.

RESULTS

IL-35 expression was increased in SSc skin and dermal fibroblasts in a TGF-β-dependent manner. IL-35 induced an activated phenotype in resting fibroblasts and enhanced the release of collagen. IL-35 serum levels were increased in patients with SSc compared with healthy controls [median 83.9 (interquartile range 45.1-146.1) vs 36.2 (interquartile range 17.2-49.4) pg/ml, P < 0.0001]. Serum IL-35 was negatively correlated with disease duration (r = -0.4339, P = 0.0052). In line with this finding, serum IL-35 was increased in patients with an early SSc pattern on capillaroscopy assessment compared with those with active and late SSc patterns.

CONCLUSION

The present study demonstrates overexpression of IL-35 in SSc skin, dermal fibroblasts and serum. TGF-β induces IL-35, which in turn activates resting fibroblasts and enhances the release of collagen, thereby contributing to aberrant TGF-β signalling in SSc. Increased serum IL-35 is associated with early, inflammatory stages of SSc.

Interleukin 35 Synovial Fluid Levels Are Associated with Disease Activity of Rheumatoid Arthritis

Objectives

To study the association of systemic and local interleukin-35 (IL-35) levels in rheumatoid arthritis.

Methods

37 patients with treatment naïve early RA, 49 with established RA and 29 control patients with osteoarthritis (OA) were studied. Serum and paired synovial fluid samples were analysed for IL-35. Disease activity of RA patients was assessed according to the 28-Joint Count Disease Activity Score (DAS28).

Results

The levels of serum IL-35 were significantly higher in patients with treatment naïve early RA compared to those with established disease and control OA subjects. In addition, serum levels of IL-35 significantly decreased 12 weeks after initiation of glucocorticoids and conventional synthetic disease modifying antirheumatic drugs in patients with treatment naïve early RA. Synovial fluid IL-35 levels were significantly higher in RA compared to OA patients, were significantly elevated compared to serum counterparts and correlated with synovial fluid leukocyte count (r=0.412; p<0.01), serum CRP levels (r=0.362; p<0.05) and DAS28 (r=0.430, p<0.01).

Conclusion

This is the first study showing elevated circulating levels of IL-35 in treatment naïve early RA, its significant decrease after treatment initiation and positive association between increased synovial fluid IL-35 and disease activity in patients with long-lasting RA.

A Population-Based Study on the Association between Benign Prostatic Enlargement and Rheumatoid Arthritis

Benign prostatic hyperplasia is one of the chronic inflammatory conditions in ageing male populations. Rheumatoid arthritis (RA) is a major autoimmune disease and is also regarded as a chronic inflammatory disorder. Although RA and benign prostatic enlargement (BPE) may share the same underlying etiologies, almost no study has ever attempted to explore the relationship between RA and BPE. The aim of this study was to explore the relationship between RA and BPE using a population-based dataset. This case-control study used data retrieved from the Taiwan Longitudinal Health Insurance Database 2005. This study comprised 18,716 patients with BPE and 18,716 age-matched patients without BPE. Conditional logistic regression analyses were performed to calculate the odds ratio (OR) for having been previously diagnosed with RA between patients with BPE and comparison patients. In total, 485 of the 37,432 sampled patients (1.3%) had received a prior RA diagnosis. There was a significant difference in the prevalence of prior RA between cases and controls (1.6% vs. 1.0%, p<0.001). After adjusting for patient's urbanization level, monthly income, geographic region, and obesity, the adjusted OR was 1.54 (95% CI = 1.28~1.85) for patients with BPE compared to comparison patients. In addition, the sensitivity analysis showed that BPE was consistently and significantly associated with a prior RA diagnosis even after excluding subjects diagnosed with RA within 1, 2, or 3 years prior to the index date (the adjusted ORs were 1.46, 1.50, and 1.42, respectively). We concluded that there was a significant association between prior RA and BPE. Further large-scale longitudinal studies are suggested to clarify the causal relationship between RA and BPE.