Th17 Cells in Immunopathogenesis and treatment of rheumatoid arthritis

Machine learning and weighted gene co-expression network analysis identify a three-gene signature to diagnose rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a systemic immune-related disease characterized by synovial inflammation and destruction of joint cartilage. The pathogenesis of RA remains unclear, and diagnostic markers with high sensitivity and specificity are needed urgently. This study aims to identify potential biomarkers in the synovium for diagnosing RA and to investigate their association with immune infiltration.

Methods

We downloaded four datasets containing 51 RA and 36 healthy synovium samples from the Gene Expression Omnibus database. Differentially expressed genes were identified using R. Then, various enrichment analyses were conducted. Subsequently, weighted gene co-expression network analysis (WGCNA), random forest (RF), support vector machine-recursive feature elimination (SVM-RFE), and least absolute shrinkage and selection operator (LASSO) were used to identify the hub genes for RA diagnosis. Receiver operating characteristic curves and nomogram models were used to validate the specificity and sensitivity of hub genes. Additionally, we analyzed the infiltration levels of 28 immune cells in the expression profile and their relationship with the hub genes using single-sample gene set enrichment analysis.

Results

Three hub genes, namely, ribonucleotide reductase regulatory subunit M2 (RRM2), DLG-associated protein 5 (DLGAP5), and kinesin family member 11 (KIF11), were identified through WGCNA, LASSO, SVM-RFE, and RF algorithms. These hub genes correlated strongly with T cells, natural killer cells, and macrophage cells as indicated by immune cell infiltration analysis.

Conclusion

RRM2, DLGAP5, and KIF11 could serve as potential diagnostic indicators and treatment targets for RA. The infiltration of immune cells offers additional insights into the underlying mechanisms involved in the progression of RA.

Long non-coding RNA ENSMUST00000197208 promotes a shift in the Th17/Treg ratio via the P2X7R-NLRP3 inflammasome axis in collagen-induced arthritis

Recently, long non‑coding RNAs (lncRNAs) have been implicated in several human diseases, including arthritis. However, the role of lncRNAs in regulating the Th17/Treg ratio during the progression of collagen-induced arthritis (CIA) is poorly understood. Therefore, the aim of this study was to determine the role of the lncRNA ENSMUST00000197208 and the P2X7R-NLRP3 inflammasome axis in changes in the Th17/Treg ratio in CIA. To achieve this, the distribution of T cell subgroups in the spleen cells of a CIA mouse model and control mice was examined. Additionally, we examined the expression profile of ENSMUST00000197208 in a CIA mouse model and healthy mice. The results showed that ENSMUST00000197208 expression was significantly upregulated in the CIA models compared with the control group. Additionally, the P2X7R-NLRP3 inflammasome axis participated in the pathogenesis of CIA and knockdown of ENSMUST00000197208 inhibited CD4+ T cell differentiation into Th17 cells. Compared with the control group, joint inflammation was less visible in NLRP3 knockout mice. Additionally, the P2X7R-NLRP3 inflammasome axis, which is downstream of ENSMUST00000197208, can be positively targeted and regulated by ENSMUST00000197208 through miR-107. Overall, the findings of this study showed that the "lncRNA ENSMUST00000197208-miR 107-P2X7R/NLRP3" axis plays an important role in CIA and knocking down ENSMUST00000197208 can efficiently inhibit Th17 differentiation by suppressing the P2X7R-NLRP3 inflammasome axis. Therefore, targeting this axis may represent a novel strategy for arthritis treatment.

Research progress of targeted therapy regulating Th17/Treg balance in bone immune diseases

Rheumatoid arthritis (RA) and postmenopausal osteoporosis (PMOP) are common bone-immune diseases. The imbalance between helper (Th17) and regulatory T cells (Tregs) produced during differentiation of CD4+ T cells plays a key regulatory role in bone remodelling disorders in RA and PMOP. However, the specific regulatory mechanism of this imbalance in bone remodelling in RA and PMOP has not been clarified. Identifying the regulatory mechanism underlying the Th17/Treg imbalance in RA and PMOP during bone remodelling represents a key factor in the research and development of new drugs for bone immune diseases. In this review, the potential roles of Th17, Treg, and Th17/Treg imbalance in regulating bone remodelling in RA and PMOP have been summarised, and the potential mechanisms by which probiotics, traditional Chinese medicine compounds, and monomers maintain bone remodelling by regulating the Th17/Treg balance are expounded. The maintenance of Th17/Treg balance could be considered as an therapeutic alternative for the treatment of RA and PMOP. This study also summarizes the advantages and disadvantages of conventional treatments and the quality of life and rehabilitation of patients with RA and PMOP. The findings presented her will provide a better understanding of the close relationship between bone immunity and bone remodelling in chronic bone diseases and new ideas for future research, prevention, and treatment of bone immune diseases.

Factors Defining Human Adipose Stem/Stromal Cell Immunomodulation in Vitro

Human adipose tissue-derived stem/stromal cells (hASCs) are adult multipotent mesenchymal stem/stromal cells with immunomodulatory capacities. Here, we present up-to-date knowledge on the impact of different experimental and donor-related factors on hASC immunoregulatory functions in vitro. The experimental determinants include the immunological status of hASCs relative to target immune cells, contact vs. contactless interaction, and oxygen tension. Factors such as the ratio of hASCs to immune cells, the cellular context, the immune cell activation status, and coculture duration are also discussed. Conditioning of hASCs with different approaches before interaction with immune cells, hASC culture in xenogenic or xenofree culture medium, hASC culture in two-dimension vs. three-dimension with biomaterials, and the hASC passage number are among the experimental parameters that greatly may impact the hASC immunosuppressive potential in vitro, thus, they are also considered. Moreover, the influence of donor-related characteristics such as age, sex, and health status on hASC immunomodulation in vitro is reviewed. By analysis of the literature studies, most of the indicated determinants have been investigated in broad non-standardized ranges, so the results are not univocal. Clear conclusions cannot be drawn for the fine-tuned scenarios of many important factors to set a standard hASC immunopotency assay. Such variability needs to be carefully considered in further standardized research. Importantly, field experts' opinions may help to make it clearer.

Plant-Based Approaches for Rheumatoid Arthritis Regulation: Mechanistic Insights on Pathogenesis, Molecular Pathways, and Delivery Systems

Rheumatoid arthritis (RA) is classified as a chronic inflammatory autoimmune disorder, associated with a varied range of immunological changes, synovial hyperplasia, cartilage destructions, as well as bone erosion. The infiltration of immune-modulatory cells and excessive release of proinflammatory chemokines, cytokines, and growth factors into the inflamed regions are key molecules involved in the progression of RA. Even though many conventional drugs are suggested by a medical practitioner such as DMARDs, NSAIDs, glucocorticoids, etc., to treat RA, but have allied with various side effects. Thus, alternative therapeutics in the form of herbal therapy or phytomedicine has been increasingly explored for this inflammatory disorder of joints. Herbal interventions contribute substantial therapeutic benefits including accessibility, less or no toxicity and affordability. But the major challenge with these natural actives is the need of a tailored approach for treating inflamed tissues by delivering these bioactive agentsat an appropriate dose within the treatment regimen for an extended periodof time. Drug incorporated with wide range of delivery systems such as liposomes, nanoparticles, polymeric micelles, and other nano-vehicles have been developed to achieve this goal. Thus, inclinations of modern treatment are persuaded on the way to herbal therapy or phytomedicines in combination with novel carriers is an alternative approach with less adverse effects. The present review further summarizes the significanceof use of phytocompounds, their target molecules/pathways and, toxicity and challenges associated with phytomolecule-based nanoformulations.

The roles of lncRNAs in Th17-associated diseases, with special focus on JAK/STAT signaling pathway

One of the most crucial T cell subsets in a variety of autoimmune and chronic inflammatory illnesses is T helper (Th) 17 cells. Th17 cells appear to have an essential role in the clearance of extracellular pathogens during infections. However, Th17 cells are also involved in inflammation and have been implicated in the pathogenesis of several autoimmune diseases and human inflammatory conditions. Due to the involvement of Th17 cells in the onset of Th17-associated diseases, understanding molecular mechanisms of Th17 cell functions may open the door to developing tailored therapies to address these difficult disorders. However, the molecular mechanisms governing Th17 differentiation in various diseases are still not well understood. The JAK/STAT signaling pathway plays a critical role in immune responses and has been linked to various aspects of Th17 cell differentiation and function. In this article, we conducted a comprehensive review of various molecular mechanisms (JAK/STAT, microRNAs, etc.), that can affect the differentiation of Th17 cells in various Th17-associated diseases.

Mechanistic prospective and pharmacological attributes of quercetin in attenuation of different types of arthritis

Arthritis is a frequent autoimmune disease with undefined etiology and pathogenesis. Scientific community constantly fascinating quercetin (QUR), as it is the best-known flavonoid among others for curative and preventive properties against a wide range of diseases. Due to its multifaceted activities, the implementation of QUR against various types of arthritis namely, rheumatoid arthritis (RA), osteoarthritis (OA), gouty arthritis (GA) and psoriotic arthritis (PsA) has greatly increased in recent years. Many research evidenced that QUR regulates a wide range of pathways for instance NF-κB, MAK, Wnt/β-catenine, Notch, etc., that are majorly associated with the inflammatory mechanisms. Besides, the bioavailability of QUR is a major constrain to its therapeutic potential, and drug delivery techniques have experienced significant development to overcome the problem of its limited application. Hence, this review compiled the cutting-edge experiments on versatile effects of QUR on inflammatory diseases like RA, OA, GA and PsA, sources and bioavailability, therapeutic challenges, pharmacokinetics, clinical studies as well as toxicological impacts. The use of QUR in a health context would offer a tearing and potential therapeutic method, supporting the advancement of public health, particularly, of arthritic patients worldwide.

Interactions of mesenchymal stromal/stem cells and immune cells following MSC-based therapeutic approaches in rheumatoid arthritis

Rheumatoid arthritis (RA) is considered to be a degenerative and progressive autoimmune disorder. Although several medicinal regimens are used to treat RA, potential adverse events such as metabolic disorders and increased risk of infection, as well as drug resistance in some patients, make it essential to find an effective and safe therapeutic approach. Mesenchymal stromal/stem cells (MSCs) are a group of non-hematopoietic stromal cells with immunomodulatory and inhibitory potential. These cells exert their regulatory properties through direct cell-to-cell interactions and paracrine effects on various immune and non-immune cells. As conventional therapeutic approaches for RA are limited due to their side effects, and some patients became refractory to the treatment, MSCs are considered as a promising alternative treatment for RA. In this review, we introduced various experimental and clinical studies conducted to evaluate the therapeutic effects of MSCs on animal models of arthritis and RA patients. Then, possible modulatory and suppressive effects of MSCs on different innate and adaptive immune cells, including dendritic cells, neutrophils, macrophages, natural killer cells, B lymphocytes, and various subtypes of T cells, were categorized and summarized. Finally, limitations and future considerations for the efficient application of MSCs as a therapeutic approach in RA patients were presented.

Molecular mechanisms of long non-coding RNAs in differentiation of T Helper17 cells

T helper (Th) 17 cells are one of the most important T cell subsets in a number of autoimmune and chronic inflammatory diseases. During infections, Th17 cells appear to play an important role in the clearance of extracellular pathogens. Th17 cells, on the other hand, are engaged in inflammation and have been linked to the pathophysiology of a number of autoimmune illnesses and human inflammatory disorders. A diverse group of RNA molecules known as lncRNAs serve critical functions in gene expression regulation. They may interact with a wide range of molecules, including DNA, RNA, and proteins, and have a complex structure. LncRNAs, which have restricted or no protein-coding activity, are implicated in a number of illnesses due to their regulatory impact on a variety of biological processes such as cell proliferation, apoptosis, and differentiation. Several lncRNAs have been associated with Th7 cell development in the context of immune cell differentiation. In this article, we cover new studies on the involvement of lncRNAs in Th17 cell differentiation in a variety of disorders, including auto-immune diseases, malignancies, asthma, heart disease, and infections.

The Fidelity of Rheumatoid Arthritis Multivariate Diagnostic Biomarkers Using Discriminant Analysis and Binary Logistic Regression

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that causes multi-articular synovitis. The illness is characterized by worsening inflammatory synovitis, which causes joint swelling and pain. Synovitis erodes articular cartilage and marginal bone, resulting in joint deterioration. This bone injury is expected to be permanent. Cytokines play a prominent role in the etiology of RA and could be useful as early diagnostic biomarkers. This research was carried out at Riyadh's King Khalid University Hospital (KKUH). Patients were enrolled from the Rheumatology unit. Seventy-eight RA patients were recruited (67 (85.9%) females and 11 (14.1%) males). Patients were selected for participation by convenience sampling. Demographic data were collected, and disease activity measurements at 28 joints were recorded using the disease activity score (DAS-28). Age- and sex-matched controls from the general population were included in the study. A panel of 27 cytokines, chemokines, and growth factors was determined in patient and control sera. Binary logistic regression (BLR) and discriminant analysis (DA) were used to analyze the data. We show that multiple cytokine biomarker profiles successfully distinguished RA patients from healthy controls. IL-17, IL-4, and RANTES were among the most predictive variables and were the only biomarkers incorporated into both BLR and DA predictive models for pooled participants (men and women). In the women-only models, the significant cytokines incorporated in the model were IL-4, IL-17, MIP-1b, and RANTES for the BLR model and IL-4, IL-1Ra, GM-CSF, IL-17, and eotaxin for the DA model. The BLR and DA men-only models contained one cytokine each, eotaxin for BLR and platelet-derived growth factor-bb (PDGF-BB) for DA. We show that BLR has a higher fidelity in identifying RA patients than DA. We also found that the use of gender-specific models marginally improves detection fidelity, indicating a possible benefit in clinical diagnosis. More research is needed to determine whether this conclusion will hold true in various and larger patient populations.

Gallic acid regulates immune response in a mouse model of rheumatoid arthritis

INTRODUCTION

Previous studies revealed that gallic acid (GA) exerts anti-inflammation and immuno-regulatory properties. This study aims to explore the pharmacological activities of GA in collagen-induced arthritis (CIA) mouse model.

METHODS

Male DBA/1J mice were used to construct the CIA model. The mice were administrated with GA for 3 weeks. Clinical arthritis scores and hind paw volume were evaluated over the experimental period. qPCR and Western blot analysis were used to determine the levels of matrix metallopeptidases (MMPs) and cytokines. In addition, flow cytometry was used to measure the populations of Th17 and Treg cells. ELISAs were used to determine the cytokines in the serum and ankle joint tissues.

RESULTS

Treatment of GA (40 and 80 mg/kg/d) reduced clinical arthritis scores and hind paw volume in the CIA mouse model. Besides, treatment of GA reduced the overexpression of MMPs and modulated the dysregulation of inflammation-related cytokines. Flow cytometry showed that treatment of GA decreased the population of Th17 cells, and increased the population of Treg cells, as supported by treatment of GA regulated the Th17/Treg-related cytokines.

CONCLUSIONS

GA attenuates symptoms in the CIA mouse model by anti-inflammation and regulating Th17/Treg cell imbalance.

Research on Liver Damage Caused by the Treatment of Rheumatoid Arthritis with Novel Biological Agents or Targeted Agents

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by polyarticular, symmetric, and aggressive inflammation of the small joints in the hands and feet, resulting in dysfunction. With progress and development in medicine, treatment of RA is constantly evolving, making several drugs available for the treatment of RA. From the nonsteroidal anti-inflammatory drugs (NSAIDs) at the start of illness to glucocorticoids and then to conventional synthetic DMARDs (csDMARDs), biologic DMARDs (bDMARDs), and targeted synthetic DMARDs (tsDMARDs), therapeutic-use drugs for RA have been keeping pace with scientific research. However, various types of drugs have additional side effects when used over the long-term. New and emerging biological and targeted agents have been widely applied in recent years; however, the side effects have not been thoroughly investigated. In this paper, we review the research progress on liver damage caused by novel biological and targeted agents available for RA treatment. The aim is to provide a reference for rational clinical administration of such drugs.

Echinocystic Acid Ameliorates Arthritis in SKG Mice by Suppressing Th17 Cell Differentiation and Human Rheumatoid Arthritis Fibroblast-Like Synoviocytes Inflammation

Echinocystic acid (EA), a pentacyclic triterpene, exhibits anti-inflammatory, antioxidant, and analgesic activities to counteract pathological effects in various diseases. Here, we aimed to determine the immunomodulatory effect of EA on zymosan-induced arthritis in SKG mice and how it would influence Th17 differentiation and human rheumatoid arthritis fibroblast-like synoviocytes inflammation. Our results showed that EA (10 and 25 mg/kg) attenuated arthritis symptoms, including high arthritis scores, infiltrating inflammatory cells, synovial hyperplasia, bone erosion, and the high levels of proinflammatory cytokines, such as TNF-α, interleukin (IL)-6, and IL-1β in paw tissues, and reduced the number of splenic Th17 cells. Mechanistically, we found that in vitro treatment of EA inhibited both IL-6- and transforming growth factor-β (TGF-β)-induced Th17 cell differentiation by suppressing the phosphorylation of signal transducers and transcriptional activators, especially STAT3. In line with the in vivo result, EA significantly reduced the protein and mRNA expression of IL-6 and IL-1β in human RA-FLA cells, MH7A cells. Furthermore, the production of both cytokines was confirmed with the downregulation of mitogen-activated protein kinases (MAPK) and nuclear factor-κB (NF-κB) signaling pathways under the stimulation of TNF-α. In conclusion, these findings revealed that EA was capable of amelioration of arthritic disorders in SKG mice through inhibiting Th17 cell differentiation and synovial fibroblast inflammation, supporting that EA is a promising therapeutic candidate for treating RA patients.

Diosmin and Trolox Have Anti-Arthritic, Anti-Inflammatory and Antioxidant Potencies in Complete Freund’s Adjuvant-Induced Arthritic Male Wistar Rats: Roles of NF-κB, iNOS, Nrf2 and MMPs

Rheumatoid arthritis (RA) is a chronic, progressive, autoimmune disease caused by a malfunction of the immune system. The aim of this study was to examine the anti-arthritic effects and suggest the mechanisms of actions of diosmin and trolox in male Wistar rats. Complete Freund’s adjuvant (CFA) was used to establish RA in the animals by subcutaneous injection of 100 µL CFA/rat into plantar region of right hind leg in two consecutive days. Diosmin and/or trolox were administered orally at a dosage of 20 mg/kg/day to CFA-induced arthritic rats for 2 weeks. The normal and arthritic control groups were orally given the same equivalent volume of a vehicle (1% carboxymethyl cellulose) in which treatment agents were dissolved. At the end of the experiment, blood samples were collected from the jugular vein for the detection of the total leukocyte count (TLC) and differential leukocyte count (DLC) in blood and the detection of rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA), tumor necrosis factor-α (TNF-α), interleukin-13 (IL-13), and interleukin-17 (IL-17) levels by enzyme-linked immunosorbent assay (ELISA), as well as markers of oxidative stress and the antioxidant defense system in serum. The right hind ankle regions of three rats from each group were dissected out and fixed in 10% neutral-buffered formalin for histological examination and the other three were kept at −30 °C for Western blot analysis of nuclear factor-kappa B (NF-κB) protein 50 (NF-κB p50), NF-κB p65, inducible nitric oxide synthase (iNOS), nuclear factor erythroid-2-related factor 2 (Nrf2), and matrix metalloproteinase (MMP)-1 (MMP-1), MMP-3, and MMP-9. The CFA injection was deleterious to the ankle joint’s histological architecture, manifesting as infiltration of inflammatory cells into the articular cartilage, hyperplasia of the synovium, and erosion of the cartilage. All these effects were ameliorated by diosmin and/or trolox, with the combined dose being the most effective. The two compounds significantly lowered the elevated serum levels of RF, ACPA, TNF-α, and IL-17, as well as other pro-inflammatory mediators, such as NF-κB p50, NF-κB p65, iNOS, MMP-1, MMP-3 and MMP-9. They also increased the levels of the anti-inflammatory cytokine, IL-13, and the cytoprotective transcription factor Nrf2. The compounds stimulated higher activities of antioxidants, such as glutathione, glutathione-S-transferase, catalase, and superoxide dismutase, and reduced lipid peroxidation in the serum of arthritic rats. In conclusion, diosmin, trolox, and their combination, which was the most potent, exerted anti-arthritic, anti-inflammatory and antioxidant effects by suppressing NF-κB signaling, inhibiting matrix metalloproteinases, and activating Nrf2.

Levels of Pathogenic Th17 and Th22 Cells in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune condition characterized, among others, by tissue damage and activation/differentiation of proinflammatory lymphocytes. Accordingly, several studies have concluded that type 17 T helper (Th17) cells seem to have an important role in the pathogenesis of this condition. However, the strategy for the identification and analysis of proinflammatory Th17 cells in those studies has not been consistent and has usually been different from what was originally described. Therefore, we decided to evaluate the levels of Th17 cells in patients with RA employing an extended immune phenotype by using an eight-color multiparametric flow cytometry analysis. For this purpose, blood samples were obtained from 30 patients with RA and 16 healthy subjects, and the levels of Th17 and type 22 helper (Th22) lymphocytes were analyzed as well as the in vitro differentiation of peripheral blood mononuclear cells into Th17 lymphocytes induced by interleukin-23 (IL-23) and IL-1β. We found significant enhanced levels of total Th17 lymphocytes (defined as CD4⁺IL-17⁺) as well as enhanced numbers of their pathogenic (defined as CD4⁺CXCR3⁺IL-17⁺IL-22⁺CD243⁺CD161⁺IFN-γ⁺IL-10⁻) and nonpathogenic (CD4⁺CXCR3⁺IL-17⁺IL-22⁻CD243⁻CD161⁻IFN-γ⁻IL-10⁺) cell subsets in patients with RA. Likewise, the number of Th22 (CD4⁺CXCR3^+/-IL-17⁻IL-22⁺) was also increased in these patients compared to healthy controls. However, the in vitro induction/differentiation of pathogenic Th17 cells showed similar results in controls and patients with RA. Likewise, no significant associations were detected in patients with RA between the levels of Th17 or Th22 cells and clinical or laboratory parameters. Our data indicate that patients with RA show enhanced blood levels of the different subsets of Th17 cells and Th22 lymphocytes tested in this study and suggest that these levels are not apparently associated with clinical or laboratory parameters.

Transcriptional Interactomic Inhibition of RORα Suppresses Th17-Related Inflammation

PURPOSE

Th17 cells and their cytokines are implicated in the pathogenesis of various autoimmune diseases. Retinoic acid-related orphan receptor alpha (RORα) is a transcription factor for the differentiation and the inflammatory functions of Th17 cells. In this study, we generated the nucleus-transducible form of transcription modulation domain of RORα (nt-RORα-TMD) to investigate the functional roles of RORα in vitro and in vivo under normal physiological condition without genetic alteration.

METHODS

The functions of nt-RORα-TMD were analyzed in vitro through flow cytometry, luciferase assay, ELISA, and transcriptome sequencing. Finally, the in vivo therapeutic effects of nt-RORα-TMD were verified in dextran sulfate sodium (DSS)-induced colitis mice.

RESULTS

nt-RORα-TMD was effectively delivered into the cell nucleus in a dose- and time-dependent manner without any cellular toxicity. nt-RORα-TMD competitively inhibited the RORα-mediated transcription but not RORγt-mediated transcription. Secretion of IL-17A from the splenocytes was suppressed by nt-RORα-TMD without affecting the secretion of Th1- or Th2-type cytokine and T cell activation events such as induction of CD69 and CD25. The differentiation potential of naïve T cells into Th17 cells, not into Th1, Th2, or Treg cells, was significantly blocked by nt-RORα-TMD. Consistently, mRNA sequencing analysis showed that nt-RORα-TMD treatment down-regulated the expression of the genes related to the differentiation and functions of Th17 cells. Treatment of DSS-induced colitis mice with nt-RORα-TMD improved the overall symptoms of colitis, such as body weight change, colon length, infiltration of inflammatory cells, and the level of inflammatory cytokines in the serum. In the mesenteric lymph node (MLN) of the nt-RORα-TMD-treated mice, the population of CD4+IL-17A+ Th17 cells was reduced, and the population of CD4+Foxp3+ Treg cells increased.

CONCLUSION

nt-RORα-TMD has a potential to be developed as a novel therapeutic reagent for treating various inflammatory diseases in which Th17 cells are the leading pathological player.

Membrane-bound IL-6R is upregulated on Th17 cells and inhibits Treg cell migration by regulating post-translational modification of VASP in autoimmune arthritis

Autoimmune arthritis is characterized by impaired regulatory T (Treg) cell migration into inflamed joint tissue and by dysregulation of the balance between Treg cells and Th17 cells. Interleukin-6 (IL-6) is known to contribute to this dysregulation, but the molecular mechanisms behind impaired Treg cell migration remain largely unknown. In this study, we assessed dynamic changes in membrane-bound IL-6 receptor (IL6R) expression levels on Th17 cells by flow cytometry during the development of collagen-induced arthritis (CIA). In a next step, bioinformatics analysis based on proteomics was performed to evaluate potential pathways affected by altered IL-6R signaling in autoimmune arthritis. Our analysis shows that membrane-bound IL-6R is upregulated on Th17 cells and is inversely correlated with IL-6 serum levels in experimental autoimmune arthritis. Moreover, IL-6R expression is significantly increased on Th17 cells from untreated patients with rheumatoid arthritis (RA). Interestingly, CD4⁺ T cells from CIA mice and RA patients show reduced phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Bioinformatics analysis based on proteomics of CD4⁺ T cells with low or high phosphorylation levels of VASP revealed that integrin signaling and related pathways are significantly enriched in cells with low phosphorylation of VASP. Specific inhibition of p-VASP reduces the migratory function of Treg cells but has no influence on effector CD4⁺ T cells. Importantly, IL-6R blockade restores the phosphorylation level of VASP, thereby improving the migratory function of Treg cells from RA patients. Thus, our results establish a link between IL6R signaling and phosphorylation of VASP, which controls Treg cell migration in autoimmune arthritis.

Immunobiology of T Cells in Sjögren's Syndrome

Sjögren's syndrome (SjS) is a systemic autoimmune disease marked by xerostomia (dry mouth), keratoconjunctivitis sicca (eye dryness), and other systematic disorders. Its pathogenesis involves an inflammatory process that is characterized by lymphocytic infiltration into exocrine glands and other tissues. Although the development of ectopic lymphoid tissue and overproduction of autoantibodies by hyperactive B cells suggest that they may promote SjS development, treatment directed towards them fails to induce significant laboratory or clinical improvement. T cells are overwhelming infiltrators in most phases of the disease, and the involvement of multiple T cell subsets of suggests the extraordinary complexity of SjS pathogenesis. The factors, including various cellular subtypes and molecules, regulate the activation and suppression of T cells. T cell activation induces inflammatory cell infiltration, B cell activation, tissue damage, and metabolic changes in SjS. Knowledge of the pathways that link these T cell subtypes and regulation of their activities are not completely understood. This review comprehensively summarizes the research progress and our understanding of T cells in SjS, including CD4⁺ T cells, CD8⁺ T_RM cells, and innate T cells, to provide insights into for clinical treatment.

The role of IL-18 in addition to Th17 cytokines in rheumatoid arthritis development and treatment in women

We aimed to analyze serum pro-inflammatory profiles of female rheumatoid arthritis (RA) patients and compare them with healthy women to establish the relative importance of pro-inflammatory cytokines in RA and their relation with different treatment regimens. Levels of six cytokines were determined by ELISA assays. A supervised dimensionality reducing approach (PLS-DA Analysis) was applied. All of the cytokines assayed were significantly elevated in the sera of RA female patients than healthy controls with fold change: 21-fold for IL-6; 6.1-fold for IL-17A; 2.5-fold for IL-23; 2.3-fold for IL-18; 1.94-fold for TNF-α; 1.7-fold for IL-12p40. According to the results of the PLS-DA analysis, IL-17A, IL-18, and TNF-α were of higher importance rank compared to IL-23 and IL-12p40. Women in the early stage of RA displayed significantly elevated IL-17A levels than those with longer disease duration: 8.04 pg/ml [8.04-175.3] vs 4.64 pg/ml [2.95-13.31], p = 0.007. IL-6 serum levels were related to higher disease activity. We have demonstrated altered cytokine production within female RA patients on different treatment regimens. Those on Tocilizumab therapy showed elevated IL-6 levels and decreased IL-17A versus the rest of the patients' subgroups. In conclusion, our data support the pivotal role of IL-18 in addition to IL-6, IL-17A, and TNF-α as the hierarchical cytokines in the pathogenesis of RA, particularly valid for women. Therapy with biological agents targeting IL-18 in addition to the Th17 axis may be an adequate approach in RA patients.

Sparstolonin B Exerts Therapeutic Effects on Collagen-Induced Arthritis by Inhibiting the NLRP3 Inflammasome and Reducing the Activity of α1,3-Fucosyltransferase

Objective. To explore the role of α1,3-fucosyltransferase in the mediation of rheumatoid arthritic inflammation, the protective effect of Sparstolonin B on rheumatoid arthritis (RA), and the mechanisms that regulate the NLRP3 inflammasome. Methods. Forty, weighing from 260-300 g, male Sprague-Dawley rats were randomly divided into the following groups: a sham operation group (Sham group), a rheumatoid arthritis model group (RA group), an RA+Sparstolonin B treatment group (RAS group), an RA+Iguratimod group (RAI group), and an RA+SsnB+NLRP3 inflammasome activator (Nigericin) group (RASN group); ten animals were allocated to each group. We determined the arthritis index for each group of rats, and pathological changes were evaluated by hematoxylin-eosin staining. We also used ELISAs to determine the serum levels of IL-17, IL-6, TNF-α, TGF-β, IL-18, and IL-1β. TUNEL staining was used to investigate apoptosis in synovial cells. IF was used to detect the release of ROS, ASC formation, and the expression levels of FucT-V and NLRP3. Western blotting was used to detect the protein expression levels of Bc1-2, Bax, TLR4, MYD88, NF-κB, pro-caspase-1, NLRP3, FucT-V, E-Selectin, and P-Selectin. We also performed in vitro experiments with Sparstolonin B and detected changes in 1,3-fucosyltransferase activity by ELISA. The pyroptosis-related phenotype, including ASC, was identified by immunofluorescence, while levels of NLRP-3, pro-IL-1, and pro-caspase-1 were detected by western blotting. Results. Sparstolonin B was showed to alleviate joint swelling in RA rats, inhibited inflammatory cell infiltration and the release of ROS, reduced damage caused by oxidative stress, and suppressed the rate of apoptosis in synovial cells. The administration of Sparstolonin B inhibited the secretion of IL-17 from Th17 cells and triggered the secretion of TGF-β from Treg cells, thus leading to the reduced expression of TLR4, MyD88, and NF-κB, and the suppression of TNF-α secretion. Moreover, Sparstolonin B downregulated the expression of NLRP3, inhibited ASC formation in vivo and in vitro, and reduced the levels of IL-18 and IL-1β. The expression levels of FucT-V, E-Selectin, and P-Selectin were also inhibited. Interestingly, these protective effects of Sparstolonin B could be blocked in RA rats by inhibiting the activation of the NLRP3 inflammasome. Conclusion. Sparstolonin B improved inflammatory responses and oxidative stress by inhibiting the NLRP3 inflammasome, inhibiting the expression of FucT-V and downregulating the TLR4/MYD88/NF-𝜅B signaling pathway in order to rescue RA.

Association of interleukin-17A rs2275913 polymorphism with rheumatoid arthritis susceptibility in Sudanese population

Objectives:

Rheumatoid arthritis is a chronic inflammatory autoimmune disease. This study aimed to determine the association of interleukin-17A-197G/A polymorphism with rheumatoid arthritis in Sudanese patients.

Methods:

A case–control study was conducted between March and December 2018. Clinical and demographic data of the study participants were collected and analyzed. Polymerase chain reaction restriction fragment length polymorphism molecular technique was done to investigate interleukin-17A-197G/A polymorphisms. All statistical tests were considered statistically significant when p < 0.05.

Results:

The study population included 266 participants aged between 1 and 85 years, with an average of 40 years, classified into 85 (31.2%) cases (mean age 48.5 ± 11.3 years), and 181 (68.8%) controls (mean age 35.3 ± 15.9 years). The interleukin-17A homozygote AA genotype was more frequent among the control group compared to the case group; 95 (52.5%) and 7 (8.2%), respectively. The homozygote GG and the heterozygote AG genotypes were proportionally not different among the cases and control groups; 13 (54.2%) and 11 (45.8%), and 65 (46.4%) and 75 (53.6%), respectively. According to the distribution of interleukin-17A genotypes, a statistically significant difference was observed among cases with the interleukin-17A AA and AG genotypes, p values 0.001 and 0.004, respectively. For the association interleukin-17A genotypes and family history a negatively significant association was reported (95% confidence interval, –0.219, p value = 0.001). There was also a negatively significant association of interleukin-17A genotypes and anti-cyclic citrullinated peptide (95% confidence interval, −0.141, p value = 0.002).

Conclusion:

This study is the first study in Sudan established the association between interleukin-17A-197G/A (rs2275913) polymorphisms and susceptibly to rheumatoid arthritis. These findings appeal for further research in Sudan to investigate the exact role of IL-17A in immunopathology and disease severity among Sudanese rheumatoid arthritis

Potential role of bioactive lipids in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease, which involves a pathological inflammatory response against articular cartilage in multiple joints throughout the body. It is a complex disorder associated with comorbidities such as depression, lymphoma, osteoporosis and cardiovascular disease (CVD), which significantly deteriorate patients' quality of life and prognosis. This has ignited a large initiative to elucidate the physiopathology of RA, aiming to identify new therapeutic targets and approaches in its multidisciplinary management. Recently, various lipid bioactive products have been proposed to have an essential role in this process; including eicosanoids, specialized pro-resolving mediators, phospholipids/sphingolipids, and endocannabinoids. Dietary interventions using omega-3 polyunsaturated fatty acids or treatment with synthetic endocannabinoids agonists have been shown to significantly ameliorate RA symptoms. Indeed, the modulation of lipid metabolism may be crucial in the pathophysiology and treatment of autoimmune diseases.

Glaucocalyxin A suppresses inflammatory responses and induces apoptosis in TNF-a-induced human rheumatoid arthritis via modulation of the STAT3 pathway

The pathogenesis of rheumatoid arthritis (RA) is characterized by synoviocyte hyperplasia and proinflammatory cytokine secretion, as well as the destruction of cartilage and bone. Glaucocalyxin A (GLA) is an alkaloid derived from a Chinese medicinal plant that exhibits anti-inflammatory, anti-tumor and neuroprotective properties. We investigated the effects of GLA on RA-fibroblast-like synoviocytes (FLS cells), and collagen-induced arthritis (CIA), and further explored the underlying mechanisms. GLA inhibited TNF-a-induced RA-FLS proliferation, increased apoptotic ratios and upregulated levels of caspase-3, cleaved PARP, and Bax. GLA also inhibited the expression of IL-10, IL-1β, and IL-6 in vitro. Levels of p-STAT3 were downregulated in a dose-dependent manner. Over-expression of STAT3 partly neutralized the GLA-mediated elevation of caspase-3 and cleaved PARP levels as well as the downregulation of IL-10, IL-1B and IL-6 expression levels. This suggests that GLA inactivated the STAT3 pathway. Furthermore, the production of inflammatory cytokines in RA-FLS and a CIA rat model were inhibited effectively by GLA. Taken together, our data suggest that GLA is a potential long-term therapeutic agent for patients with RA.

Therapeutic Effects of Tryptanthrin and Tryptanthrin-6-Oxime in Models of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease involving joint and bone damage that is mediated in part by proteases and cytokines produced by synovial macrophages and fibroblast-like synoviocytes (FLS). Although current biological therapeutic strategies for RA have been effective in many cases, new classes of therapeutics are needed. We investigated anti-inflammatory properties of the natural alkaloid tryptanthrin (TRYP) and its synthetic derivative tryptanthrin-6-oxime (TRYP-Ox). Both TRYP and TRYP-Ox inhibited matrix metalloproteinase (MMP)-3 gene expression in interleukin (IL)-1β-stimulated primary human FLS, as well as IL-1β–induced secretion of MMP-1/3 by FLS and synovial SW982 cells and IL-6 by FLS, SW982 cells, human umbilical vein endothelial cells (HUVECs), and monocytic THP-1 cells, although TRYP-Ox was generally more effective and had no cytotoxicity in vitro. Evaluation of the therapeutic potential of TRYP and TRYP-Ox in vivo in murine arthritis models showed that both compounds significantly attenuated the development of collagen-induced arthritis (CIA) and collagen-antibody–induced arthritis (CAIA), with comparable efficacy. Collagen II (CII)-specific antibody levels were similarly reduced in TRYP- and TRYP-Ox-treated CIA mice. TRYP and TRYP-Ox also suppressed proinflammatory cytokine production by lymph node cells from CIA mice, with TRYP-Ox being more effective in inhibiting IL-17A, granulocyte-macrophage colony-stimulating factor (GM-CSF), and receptor activator of nuclear factor-κB ligand (RANKL). Thus, even though TRYP-Ox generally had a better in vitro profile, possibly due to its ability to inhibit c-Jun N-terminal kinase (JNK), both TRYP and TRYP-Ox were equally effective in inhibiting the clinical symptoms and damage associated with RA. Overall, TRYP and/or TRYP-Ox may represent potential new directions for the pursuit of novel treatments for RA.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

TonEBP in dendritic cells mediates pro-inflammatory maturation and Th1/Th17 responses

Dendritic cells (DCs) are potent antigen-presenting cells that link the innate and adaptive immune responses; as such they play pivotal roles in initiation and progression of rheumatoid arthritis (RA). Here, we report that the tonicity-responsive enhancer-binding protein (TonEBP or NFAT5), a Rel family protein involved in the pathogenesis of autoimmune disease and inflammation, is required for maturation and function of DCs. Myeloid cell-specific TonEBP deletion reduces disease severity in a murine model of collagen-induced arthritis; it also inhibits maturation of DCs and differentiation of pathogenic Th1 and Th17 cells in vivo. Upon stimulation by TLR4, TonEBP promotes surface expression of major histocompatibility complex class II and co-stimulatory molecules via p38 mitogen-activated protein kinase. This is followed by DC-mediated differentiation of pro-inflammatory Th1 and Th17 cells. Taken together, these findings provide mechanistic basis for the pathogenic role of TonEBP in RA and possibly other autoimmune diseases.

Berberine mitigates IL-21/IL-21R mediated autophagic influx in fibroblast-like synoviocytes and regulates Th17/Treg imbalance in rheumatoid arthritis

In our previous study, we explored the therapeutic effect of berberine (BBR) against IL-21/IL-21R mediated inflammatory proliferation of adjuvant-induced arthritic fibroblast-like synoviocytes (AA-FLS) through the PI3K/Akt pathway. The current study was designed to explore the therapeutic potential of BBR (15-45 µM) against IL-21/IL-21R mediated autophagy in AA-FLS mediated through PI3K/Akt signaling and Th17/Treg imbalance. Upon IL-21 stimulation, AA-FLS expressed elevated levels of autophagy-related 5 (Atg5), Beclin-1 and LC3-phosphatidylethanolamine conjugate 3-II (LC3-II) through the utilization of p62 and inhibition of C/EBP homologous protein (CHOP). BBR (15-45 µM) inhibited autophagy in AA-FLS cells mediated through PI3K/Akt signaling via suppressing autophagic elements, p62 sequestration and induction of CHOP in a dose-dependent manner. Moreover, IL-21 promoted the uncontrolled proliferation of AA-FLS through induction of B cell lymphoma-2 (Bcl-2) and diminished expression of Bcl-2 associated X protein (BAX) via PI3K/Akt signaling. BBR inhibited the proliferation of AA-FLS via promoting apoptosis through increased expression of BAX and diminished Bcl-2 transcription factor levels. Furthermore, T cells stimulated with IL-21 induced CD4⁺ CD196⁺ Th17 cells proliferation through RORγt activation mediated in a PI3K/Akt dependent manner. BBR inhibited the proliferation of Th17 cells through downregulation of RORγt in a concentration-dependent manner. BBR also promoted the differentiation of CD4⁺ CD25⁺ Treg cells through induction of forkhead box P3 (Foxp3) activation via aryl hydrocarbon receptor (AhR) and upregulation of cytochrome P450 family 1, subfamily A, polypeptide 1 (CYP1A1). Collectively, we conclude that BBR might attenuate AA-FLS proliferation through inhibition of IL-21/IL-21R dependent autophagy and regulates the Th17/Treg imbalance in RA.

Update on the Pathomechanism, Diagnosis, and Treatment Options for Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that involves multiple joints bilaterally. It is characterized by an inflammation of the tendon (tenosynovitis) resulting in both cartilage destruction and bone erosion. While until the 1990s RA frequently resulted in disability, inability to work, and increased mortality, newer treatment options have made RA a manageable disease. Here, great progress has been made in the development of disease-modifying anti-rheumatic drugs (DMARDs) which target inflammation and thereby prevent further joint damage. The available DMARDs are subdivided into (1) conventional synthetic DMARDs (methotrexate, hydrochloroquine, and sulfadiazine), (2) targeted synthetic DMARDs (pan-JAK- and JAK1/2-inhibitors), and (3) biologic DMARDs (tumor necrosis factor (TNF)-α inhibitors, TNF-receptor (R) inhibitors, IL-6 inhibitors, IL-6R inhibitors, B cell depleting antibodies, and inhibitors of co-stimulatory molecules). While DMARDs have repeatedly demonstrated the potential to greatly improve disease symptoms and prevent disease progression in RA patients, they are associated with considerable side-effects and high financial costs. This review summarizes our current understanding of the underlying pathomechanism, diagnosis of RA, as well as the mode of action, clinical benefits, and side-effects of the currently available DMARDs.

Th17/IL-17 Axis Regulated by Airway Microbes Get Involved in the Development of Asthma

PURPOSE OF REVIEW

Bronchial asthma is a common respiratory disease induced by immune imbalance, characterized by chronic non-specific airway inflammation and airway hyperresponsiveness (AHR). Many factors induce asthma, among which respiratory infection is the important cause. In this review, we discuss how respiratory microbes participate in the occurrence and progression of asthma via Th17/IL-17 axis.

RECENT FINDINGS

Pathogenesis of asthma has been considered as closely related to the imbalance in number and function of Th1/Th2 in the CD4⁺ T lymphocyte subsets. Recent studies have shown that Th17 cell and its secretory IL-17 also play an important role in AHR. Respiratory virus, bacteria, fungi, and other respiratory microbial infections can directly or indirectly induce the differentiation of Th17 cell and the production of related cytokines to induce AHR. Respiratory microbial infection can affect the TH17/IL-17A axis through a variety of mechanisms, thereby promoting the occurrence and development of asthma, and these specific mechanisms may provide new effective therapeutic ideas for asthma.

Differential Expression of SMAD Genes and S1PR1 on Circulating CD4+ T Cells in Multiple Sclerosis and Crohn's Disease

The Th17 immune response plays a key role in autoimmune diseases such as multiple sclerosis (MS) and inflammatory bowel disease (IBD). Expression of Th17-related genes in inflamed tissues has been reported in autoimmune diseases. However, values are frequently obtained using invasive methods. We aimed to identify biomarkers of MS in an accessible sample, such as blood, by quantifying the relative expression of 91 Th17-related genes in CD4+ T lymphocytes from patients with MS during a relapse or during a remitting phase. We also compared our findings with those of healthy controls. After confirmation in a validation cohort, expression of SMAD7 and S1PR1 mRNAs was decreased in remitting disease (-2.3-fold and -1.3-fold, respectively) and relapsing disease (-2.2-fold and -1.3-fold, respectively). No differential expression was observed for other SMAD7-related genes, namely, SMAD2, SMAD3, and SMAD4. Under-regulation of SMAD7 and S1PR1 was also observed in another autoimmune disease, Crohn's disease (CD) (-4.6-fold, -1.6-fold, respectively), suggesting the presence of common markers for autoimmune diseases. In addition, expression of TNF, SMAD2, SMAD3, and SMAD4 were also decreased in CD (-2.2-fold, -1.4-fold, -1.6-fold, and -1.6-fold, respectively). Our study suggests that expression of SMAD7 and S1PR1 mRNA in blood samples are markers for MS and CD, and TNF, SMAD2, SMAD3, and SMAD4 for CD. These genes could prove useful as markers of autoimmune diseases, thus obviating the need for invasive methods.

T-Follicular Regulatory Cells: Potential Therapeutic Targets in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an incurable aggressive chronic inflammatory joint disease with a worldwide prevalence. High levels of autoantibodies and chronic inflammation may be involved in the pathology. Notably, T follicular regulatory (Tfr) cells are critical mediators of T follicular helper (Tfh) cell generation and antibody production in the germinal center (GC) reaction. Changes in the number and function of Tfr cells may lead to dysregulation of the GC reaction and the production of aberrant autoantibodies. Regulation of the function and number of Tfr cells could be an effective strategy for precisely controlling antibody production, reestablishing immune homeostasis, and thereby improving the outcome of RA. This review summarizes advances in our understanding of the biology and functions of Tfr cells. The involvement of Tfr cells and other immune cell subsets in RA is also discussed. Furthermore, we highlight the potential therapeutic targets related to Tfr cells and restoring the Tfr/Tfh balance via cytokines, microRNAs, the mammalian target of rapamycin (mTOR) signaling pathway, and the gut microbiota, which will facilitate further research on RA and other immune-mediated diseases.

Exploring Frequencies of Circulating Specific Th17 Cells against Myeloperoxidase and Proteinase 3 in ANCA Associated Vasculitis

Background: The role of the T helper 17 (Th17) cell subset in anti-neutrophil cytoplasm antibodies (ANCA) associated vasculitis (AAV) is controversial. We hypothesized that a specific Th17 response to myeloperoxidase (MPO) or proteinase 3 (PR3) is detectable in AAV patients and is different among the disease phases. Methods: We analyzed 43 AAV patients with renal involvement (21 acute and 22 remission patients), and 12 healthy controls. Peripheral blood mononuclear cells (PBMCs) were cultured with PR3/MPO over 48 h. Thereafter, frequencies of MPO/PR3-specific Th17 cells were assessed using an enzyme-linked immunosorbent spot (ELISpot) assay. Supernatant IL-17 concentration was quantified using ELISA. Finally, specific Th17 response after depletion of T regulatory lymphocytes (T-regs) in some remission patients was compared to the non T-reg-depleted response. Results: Specific Th17 cell number was higher in acute patients compared to remission (p = 0.004). Specific Th17 cell number performed well in the disease activity detection (ROC curve area under the curve (AUC) = 0.87; p = 0.0001) with an optimal cut-off of 6 spots/million. Patients above this cut-off showed higher serum creatinine (p = 0.004), C-reactive protein (CRP) (p = 0.001) and ANCA titer (p = 0.032). Supernatant IL-17 concentration was higher in acute patients compared to remission (p = 0.035) and did not normalize to healthy control levels (p = 0.01). Conclusions: A specific Th17 cell response is present in AAV patients. This response is more pronounced in the acute phase, but persists in remission.

Effect of IL-21 on the Balance of Th17 Cells/Treg Cells in the Pathogenesis of Graves' Disease

Graves' disease (GD) is a common organ-specific autoimmune disease, and its pathogenesis is still unclear. The aim of this study is to investigate the role of interleukin (IL)-21 in the regulation of Th17/Treg cells in GD. We recruited 28 newly diagnosed GD patients, 27 GD patients in remission (eGD), and 24 normal controls (NC). Thyroid function and autoantibodies were evaluated by electrochemical luminescence. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with or without recombinant human interleukin-21 (rhIL-21), and mRNA and protein levels were quantified by real-time PCR and ELISA, respectively. Compared with those in the eGD and control groups, the thyroid function indexes and autoantibodies levels were significantly different in the GD group (P < 0.05). Without rhIL-21 stimulation, the expression levels of retinoid-related orphan gamma t (RORγt), IL-17, IL-22, forkhead box protein P3 (Foxp3) and IL-10 mRNA and the IL-10 and IL-22 proteins were significantly higher in the GD group than those in the eGD and control groups (P < 0.05). rhIL-21 stimulation increased the RORγt, IL-17, and IL-22 mRNA levels and IL-22 protein levels and decreased the Foxp3 and IL-10 mRNA levels and IL-10 protein levels (P < 0.05) in the GD group. In conclusion, our analyses demonstrated that IL-21 might induce the differentiation of CD4⁺ T cells to Th17 cells and reduce Treg cell differentiation, which could contribute to activation of the downstream immune response and the pathogenesis of GD.

Suberoylanilide Hydroxamic Acid Attenuates Autoimmune Arthritis by Suppressing Th17 Cells through NR1D1 Inhibition

Rheumatoid arthritis (RA) is a type of systemic autoimmune arthritis that causes joint inflammation and destruction. One of the pathological mechanisms of RA is known to involve histone acetylation. Although the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) can attenuate arthritis in animal models of RA, the mechanism underlying this effect is poorly understood. This study was performed to examine whether SAHA has therapeutic potential in an animal model of RA and to investigate its mechanism of action. Collagen-induced arthritis (CIA) mice were orally administered SAHA daily for 8 weeks and examined for their arthritis score and incidence of arthritis. CD4⁺ T cell regulation following SAHA treatment was confirmed in splenocytes cultured under type 17 helper T (Th17) cell differentiation conditions. Clinical scores and the incidence of CIA were lower in mice in the SAHA treatment group compared to the controls. In addition, SAHA inhibited Th17 cell differentiation, as well as decreased expression of the Th17 cell-related transcription factors pSTAT3 Y705 and pSTAT3 S727. In vitro experiments showed that SAHA maintained regulatory T (Treg) cells but specifically reduced Th17 cells. The same results were obtained when mouse splenocytes were cultured under Treg cell differentiation conditions and then converted to Th17 cell differentiation conditions. In conclusion, SAHA was confirmed to specifically inhibit Th17 cell differentiation through nuclear receptor subfamily 1 group D member 1 (NR1D1), a factor associated with Th17 differentiation. The results of the present study suggested that SAHA can attenuate CIA development by inhibition of the Th17 population and maintenance of the Treg population through NR1D1 inhibition. Therefore, SAHA is a potential therapeutic candidate for RA.

Gums and joints: is there a connection? Part two: the biological link

Rheumatoid arthritis (RA) and periodontitis (PD) are inflammatory diseases characterised by an exacerbated immune-inflammatory reaction that leads to the destruction of bone and other connective tissues that share numerous similarities. Although a significant and independent association between these two conditions has been described, the pathophysiological processes that may explain this relationship remain unknown and multiple theories have been proposed. This review presents the most important theories currently proposed to explain the biological link between RA and PD.

Salivary interleukin 6, interleukin 8, interleukin 17A, and tumour necrosis factor α levels in patients with periodontitis and rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) and periodontitis share risk factors and inflammatory pathways that could be related to cytokines, such as interleukin (IL)-6, IL-8, IL-17A, and tumour necrosis factor-α (TNF-α). The aim of this study was to compare periodontal status and salivary levels of selected cytokines between patients diagnosed with RA and periodontitis. RA patients were assessed for the potential influence of anti-rheumatic therapy.

Material and methods

One hundred and six patients were enrolled in a cross-sectional study. Medical assessment and periodontal examination were performed in 35 patients with chronic periodontitis, in 35 patients with RA and chronic periodontitis, and in 36 controls. Unstimulated whole saliva samples were analysed for IL-6, IL-8, IL-17A, and TNF-α.

Results

Significant differences in biomarkers and periodontal parameters were found among groups. Study groups exhibited higher mean pocket depth (PD), number of PD > 4 mm, and mean clinical attachment loss, when compared with controls. The RA group had lower bleeding on probing index and PD, but higher values of plaque indices than the periodontitis group. Concentration of evaluated cytokines were higher in the RA and periodontitis groups, compared with controls. The periodontitis group showed also higher levels of IL-6, IL-17A, and TNF-α in comparison to RA. RA patients were treated with disease-modifying anti-rheumatic drugs (DMARDs) and glucocorticosteroids.

Conclusions

Salivary levels of IL-6, IL-8, IL-17A, and TNF-α can be affected by periodontitis, RA, and presumably DMARDs. DMARD therapy appears to reduce destructive and inflammatory processes in periodontal tissues because lower values of PD, BOP, and salivary levels of IL-6, IL-17A, and TNF-α were found in RA.

Human disorders associated with inflammation and the evolving role of natural products to overcome

Inflammation is a biological function which triggered after the mechanical tissue disruption or from the responses by the incidence of physical, chemical or biological negotiator in body. These responses are essential act provided by the immune system during infection and tissue injury to maintain normal tissue homeostasis. Inflammation is a quite complicated process at molecular level with the involvement of several proinflammatory expressions. Several health problems are associated with prolonged inflammation, which effects nearly all major to minor diseases. The molecular and epidemiological studies jagged that the inflammation is closely associated with several disorders with their specific targets. It would be great achievement for human health around the world to overcome on inflammation. Mostly used anti-inflammatory drugs are at high risk of side effects and also expensive. Hence, the plant-based formulations gained a wide acceptance by the public and medical experts to treat it. Due to extensive dispersal, chemical diversity and systematically established biological potentials of natural products have induced renewed awareness as a gifted source for medications. However, today's urgent need to search for cheaper, more potent and safe anti-inflammatory medications to overcome on current situation. The goal of this review to compile an update on inflammation, associated diseases, molecular targets, inflammatory mediators and role of natural products. The entire text concise the involvement of various cytokines in pathogenesis of various human disorders. This assignment discussed about 321 natural products with their promising anti-inflammatory potential discovered during January 2009 to December 2018 with 262 citations.

Atractylodin Suppresses Dendritic Cell Maturation and Ameliorates Collagen-Induced Arthritis in a Mouse Model

The aim of this study was to evaluate the immunomodulatory effects of atractylodin, a polyethylene alkyne, on the maturation of bone marrow-derived dendritic cells (BM-DC) as well as its antirheumatic effect on collagen-induced arthritis (CIA) in DBA/1 mice. Our results indicate that atractylodin effectively suppressed the secretion of pro-inflammatory cytokines, expression of costimulatory molecules, and p38 MAPK, ERK, and NF-κBp65 signaling pathways in LPS-incubated dendritic cells (DCs). Additionally, the proliferation and cytokine secretion (IFN-γ and IL-17A) of CD8⁺ and CD4⁺ T cells were reduced. In a murine CIA model, intraperitoneal injection of atractylodin significantly alleviated the severity of the disease progression, as indicated by reduced paw swelling, clinical arthritis scores, and pathological changes of joint tissues. In addition, the overall proliferation of T cells stimulated by type II collagen and the abundance of Th1 and Th17 in the spleens were also significantly decreased with atractylodin treatments. Furthermore, atractylodin significantly downregulated the expression levels of CD40, CD80, and CD86 of DCs in the spleens. In conclusion, this study shows for the first time that atractylodin has potential to manipulate the maturation of BM-DCs and should be further explored as a therapeutic agent in the treatment of rheumatoid arthritis (RA).

Dendritic cells, T cells and their interaction in rheumatoid arthritis

Dendritic cells (DCs) are the key professional antigen-presenting cells which bridge innate and adaptive immune responses, inducing the priming and differentiation of naive to effector CD4+ T cells, the cross-priming of CD8+ T cells and the promotion of B cell antibody responses. DCs also play a critical role in the maintenance of immune homeostasis and tolerance. DC-T cell interactions underpin the generation of an autoimmune response in rheumatoid arthritis (RA). Here we describe the function of DCs and review evidence for DC and T cell involvement in RA pathogenesis, in particular through the presentation of self-peptide by DCs that triggers differentiation and activation of autoreactive T cells. Finally, we discuss the emerging field of targeting the DC-T cell interaction for antigen-specific immunotherapy of RA.

A role for Th1-like Th17 cells in the pathogenesis of inflammatory and autoimmune disorders

The T helper 17 (Th17) cells contain a dynamic subset of CD4+ T-cells that are able to develop into other different lineage subsets, including the Th1-like Th17 cells. These cells co-express retinoic acid-related orphan receptor gamma t (RORγt) and transcription factor T-box-expressed-in-T-cells (T-bet) and produce both interleukin (IL)-17 and interferon (IFN)-γ. Recent reports have shown that Th1-like Th17 cells play crucial roles in the pathogenesis of autoimmune diseases such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, as well as, some primary immunodeficiency with autoimmune features. Here, the actual mechanisms for Th17 cells plasticity to Th1-like Th17 cells are discussed and reviewed in association to the role that Th1-like Th17 cells have on inflammatory and autoimmune disorders.

Amelioration of clinical symptoms of patients with refractory rheumatoid arthritis following treatment with autologous bone marrow-derived mesenchymal stem cells: A successful clinical trial in Iran

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune arthropathy characterized by synovial hyperplasia leading to functional impairment. Although the exact cause of RA is unknown, there is evidence suggesting the role of T cell subtypes in the pathogenesis of RA. Conventional therapy in some RA patients is associated with mild or severe side effects, and resistance of some patients has been reported to these types of therapy. The therapeutic potential of mesenchymal stem cells (MSCs) introduced them as a novel therapeutic choice for the treatment of rheumatic diseases. The aim of our study was to evaluate the effects of intravenous administration of autologous bone marrow-derived MSCs on the immunological, clinical and para-clinical factors such as regulatory T cells, Th17 cells, CD8+ T cells, CD4+ T cells, disease activity score 28-erythrocyte sedimentation rate (DAS28-ESR), visual analogue scale (VAS), ESR, C-reactive protein (CRP), rheumatoid factor (RF), and anti-cyclic citrullinated peptide (anti-CCP) antibodies in patients with refractory RA. Nine refractory RA patients with no other rheumatologic disorders were included in this study. All patients received a single intravenous dose of 1 × 10⁶ autologous bone marrow-derived MSCs/kg, and were followed up at 1, 6 and 12 months after injection of MSCs. We found a significant decreasing trend in Th17 percentage and geometric mean fluorescence intensity for IL-17A following injection of MSCs at 12 months compared to the time point zero. Furthermore, a significant increase in regulatory T cells percentage was observed at the end of the first month after the intervention. DAS28-ESR decreased significantly at 1 and 12 months after MSC therapy. VAS score showed a significant decreasing trend during the follow-up periods. No significant difference was found for serum CRP and anti-CCP levels after the intervention. In conclusion, our data indicated that clinical symptoms were significantly ameliorated following the intravenous injection of autologous bone marrow-derived MSCs to the patients with refractory RA.

Rheumatoid arthritis and the mucosal origins hypothesis: protection turns to destruction

Individuals at high risk of developing seropositive rheumatoid arthritis (RA) can be identified for translational research and disease prevention studies through the presence of highly informative and predictive patterns of RA-related autoantibodies, especially anti-citrullinated protein antibodies (ACPAs), in the serum. In serologically positive individuals without arthritis, designated ACPA positive at risk, the presence of mucosal inflammatory processes associated with the presence of local ACPA production has been demonstrated. In other at-risk populations, local RA-related autoantibody production is present even in the absence of serum autoantibodies. Additionally, a proportion of at-risk individuals exhibit local mucosal ACPA production in the lung, as well as radiographic small-airway disease, sputum hypercellularity and increased neutrophil extracellular trap formation. Other mucosal sites in at-risk individuals also exhibit autoantibody production, inflammation and/or evidence of dysbiosis. As the proportion of individuals who exhibit such localized inflammation-associated ACPA production is substantially higher than the likelihood of an individual developing future RA, this finding raises the hypothesis that mucosal ACPAs have biologically relevant protective roles. Identifying the mechanisms that drive both the generation and loss of externally focused mucosal ACPA production and promote systemic autoantibody expression and ultimately arthritis development should provide insights into new therapeutic approaches to prevent RA.

Sodium chloride triggers Th17 mediated autoimmunity

The detrimental effects of a high-salt diet on human health have received much attention in the past few years. While it has been well established that high dietary salt intake is related to cardiovascular diseases, there is growing evidence that excess salt also affects the immune system and might be considered as a risk factor in autoimmune diseases such as multiple sclerosis (MS). Several studies have implicated T helper 17 cells (Th17) in the pathogenesis of MS. We and others recently demonstrated that excessive salt enhances the differentiation of Th17 cells, inducing a highly pathogenic phenotype that aggravates experimental neuroinflammation. Moreover, a diet rich in sodium affects intestinal microbiota alongside increased intestinal Th17 cells, thus linking the detrimental effects of high salt consumption to the gut-immune axis. First human studies revealed an association of increased MS disease activity with elevated sodium chloride consumption, while more recent epidemiology studies in larger cohorts suggest no correlation between salt intake and MS. However, it is known that ordinary urinary sodium analyses and nutritional questionnaires do not necessarily correspond to the actual sodium load and more sophisticated analyses are needed. Moreover, studies revealed that sodium can temporarily be stored in the body. This review summarizes recent findings on the impact of salt on the immune system and discusses potential challenges investigating dietary salt intake as a risk factor in MS.

Impacts of microbiome metabolites on immune regulation and autoimmunity

A vast number of studies have demonstrated a remarkable role for the gut microbiota and their metabolites in the pathogenesis of inflammatory diseases, including multiple sclerosis (MS). Recent studies in experimental autoimmune encephalomyelitis, an animal model of MS, have revealed that modifying certain intestinal bacterial populations may influence immune cell priming in the periphery, resulting in dysregulation of immune responses and neuroinflammatory processes in the central nervous system (CNS). Conversely, some commensal bacteria and their antigenic products can protect against inflammation within the CNS. Specific components of the gut microbiome have been implicated in the production of pro-inflammatory cytokines and subsequent generation of Th17 cells. Similarly, commensal bacteria and their metabolites can also promote the generation of regulatory T-cells (Treg), contributing to immune suppression. Short-chain fatty acids may induce Treg either by G-protein-coupled receptors or inhibition of histone deacetylases. Tryptophan metabolites may suppress inflammatory responses by acting on the aryl hydrocarbon receptor in T-cells or astrocytes. Interestingly, secretion of these metabolites can be impaired by excess consumption of dietary components, such as long-chain fatty acids or salt, indicating that the diet represents an environmental factor affecting the complex crosstalk between the gut microbiota and the immune system. This review discusses new aspects of host-microbiota interaction and the immune system with a special focus on MS as a prototype T-cell-mediated autoimmune disease of the CNS.

The role of interleukin-4 in rheumatic diseases

Rheumatism is a group of diseases, most of which are autoimmune diseases, that violate joints, bones, muscles, blood vessels and related soft tissue. As is well known, cytokines play a role in the pathogenesis of several rheumatic diseases, such as rheumatoid arthritis, spondyloarthritides, and systemic lupus erythematosus. Recently, the role of interleukin-4 (IL-4), which may participate in the mechanism of rheumatism, have been discovered. It is reported that IL-4 takes part in the regulation of T cell activation, differentiation, proliferation, and survival of different T cell types. IL-4 also has an immunomodulatory effect on B cells, mast cells, macrophages, and many cell types. A review of the literature on functions of IL-4 in rheumatic diseases is presented.