Th17 Cells In Rheumatoid Arthritis Research Articles

The Interplay between Transcriptional Factors and MicroRNAs as an Important Factor for Th17/Treg Balance in RA Patients

MicroRNAs regulate gene expression of transcriptional factors, which influence Th17/Treg (regulatory T cells) balance, establishing the molecular mechanism of genetic and epigenetic regulation of Treg and Th17 cells is crucial for understanding rheumatoid arthritis (RA) pathogenesis. The study goal was to understand the potential impact of the selected microRNAs expression profiles on Treg/Th17 cells frequency, RA phenotype, the expression profile of selected microRNAs, and their correlation with the expression profiles of selected transcriptional factors: SOCS1, SMAD3, SMAD4, STAT3, STAT5 in RA; we used osteoarthritis (OA) and healthy controls (HCs) as controls. The study was conducted on 14 RA and 11 OA patients, and 15 HCs. Treg/Th17 frequency was established by flow cytometry. Gene expression analysis was estimated by qPCR. We noticed correlations in RA Th17 cells between miR-26 and SMAD3, STAT3, SOCS1; and miR-155 and STAT3—and in RA Treg cells between miR-26 and SOCS1; miR-31, -155 and SMAD3; and miR-155 and SMAD4. In RA Tregs, we found a negative correlation between miR-26, -126 and STAT5a. The expression level of miR-31 in Th17 cells from RA patients with DAS28 ≤ 5.1 is higher and that for miR-24 is greater in Tregs from patients with DAS28 > 5.1. MiR-146a in Tregs is higher in rheumatoid factor (RF) positive RA patients.

Comprehensive TCR repertoire analysis of CD4+ T-cell subsets in rheumatoid arthritis

The pathogenesis of rheumatoid arthritis (RA), a systemic autoimmune disease characterized by autoreactive T-cell accumulation and pro-inflammatory cytokine overproduction, is unclear. Systematically addressing T-cell receptor (TCR) repertoires of different CD4+ T-cell subsets could help understand RA pathogenesis. Here, peripheral CD4+ T cells from treatment-naïve RA patients and healthy controls were sorted into seven subsets including naïve, effector, central memory, effector memory (EMT), Th1, Th17, and regulatory T cells. T-cell receptor β chain repertoires were then analyzed by next-generation sequencing. We identified T-cell clonal expansion in EMT and Th17 cells of RA patients, with highly similar TCR repertoires. Ex vivo experiments demonstrated the preferred differentiation from EMT to Th17 cells in RA. Notably, we showed that TCR diversity and abundance of differentiated T cells of Th17 were significantly correlated with RA disease activity. Based on these observations, we propose that abnormal differentiation from EMT to Th17 and expansion of Th17 play pivotal role in RA pathogenesis.

Th17 cell pathogenicity and plasticity in rheumatoid arthritis.

CD4+ Th cells play an important role in the development of rheumatoid arthritis (RA) by regulating adaptive immune response. As major subsets of CD4+ Th cells, Th17 cells can produce a large number of hallmark cytokines such as IL-17A and IL-17F, which participate in host defense and immune homeostasis. However, increasing researches have shown that Th17 cells are unstable and exhibit a certain degree of plasticity, which aggravates their pathogenicity. Furthermore, the plasticity and pathogenicity of Th17 cells are closely related with the disease activity in RA. In this paper, the characteristics including phenotype, differentiation, plasticity, and pathogenicity of Th17 cells in RA will be systematically summarized. This will contribute to clarify the immunologic mechanism of RA and further provide a novel strategy for the clinical treatment of autoimmune diseases.

Specific Inhibition of Soluble γc Receptor Attenuates Collagen-Induced Arthritis by Modulating the Inflammatory T Cell Responses.

IL-17 produced by Th17 cells has been implicated in the pathogenesis of rheumatoid arthritis (RA). It is important to prevent the differentiation of Th17 cells in RA. Homodimeric soluble γc (sγc) impairs IL-2 signaling and enhances Th17 differentiation. Thus, we aimed to block the functions of sγc by inhibiting the formation of homodimeric sγc. The homodimeric form of sγc was strikingly disturbed by sγc-binding DNA aptamer. Moreover, the aptamer effectively inhibited Th17 cell differentiation and restored IL-2 and IL-15 signaling impaired by sγc with evidences of increased survival of T cells. sγc was highly expressed in SF of RA patients and increased in established CIA mice. The therapeutic effect of PEG-aptamer was tested in CIA model and its treatment alleviated arthritis pathogenesis with impaired differentiation of pathogenic Th17, NKT1, and NKT17 cells in inflamed joint. Homodimeric sγc has pathogenic roles to exacerbate RA progression with differentiation of local Th17, NKT1, and NKT17 cells. Therefore, sγc is suggested as target of a therapeutic strategy for RA.

The IL-20 Cytokine Family in Rheumatoid Arthritis and Spondyloarthritis.

This review describes the IL-20 family of cytokines in rheumatoid arthritis (RA) and spondyloartrhitits (SpA) including psoriatic arthritis. The IL-20 receptor (R) cytokines IL-19, IL-20, and IL-24 are produced in both the peripheral blood and the synovial joint and are induced by Toll-like receptor ligands and autoantibody-associated immune complexes in monocytes. IL-19 seems to have anti-inflammatory functions in arthritis. In contrast, IL-20 and IL-24 increase the production of proinflammatory molecules such as monocyte chemoattractant protein 1 and are associated with bone degradation and radiographic progression. IL-22 is also associated with progression of bone erosions. This suggests that the IL-22RA1 subunit shared by IL-20, IL-22, and IL-24 is important for bone homeostasis. In line with this, the IL-22RA1 has been found on preosteoclasts in early RA. IL-26 is produced in high amounts by myofibroblasts and IL-26 stimulation of monocytes is an important inducer of Th17 cells in RA. This indicates a role for IL-26 as an important factor in the interactions between resident synovial cells and infiltrating leukocytes. Clinical trials that investigate inhibitors of IL-20 (fletikumab) and IL-22 (fezakinumab) in psoriasis and RA have been terminated. Instead, it seems that the strategy for modulating the IL-20 cytokine family should take the overlap in cellular sources and effector mechanisms into account. The redundancy encourages inhibition of more than one cytokine or one of the shared receptors. All IL-20 family members utilize the Janus kinase signaling pathway and are therefore potentially inhibited by drugs targeting these enzymes. Effects and adverse effects in ongoing clinical trials with inhibitors of IL-22 and the IL-22RA1 subunit and recombinant IL-22 fusion proteins will possibly provide important information about the IL-20 subfamily of cytokines in the future.

Synovial IL-9 facilitates neutrophil survival, function and differentiation of Th17 cells in rheumatoid arthritis

BackgroundRole of Th9 cells and interleukin-9 (IL-9) in human autoimmune diseases such as psoriasis and ulcerative colitis has been explored only very recently. However, their involvement in human rheumatoid arthritis (RA) is not conclusive. Pathogenesis of RA is complex and involves various T cell subsets and neutrophils. Here, we aimed at understanding the impact of IL-9 on infiltrating immune cells and their eventual role in synovial inflammation in RA.MethodsIn vitro stimulation of T cells was performed by engagement of anti-CD3 and anti-CD28 monoclonal antibodies. Flow cytometry was employed for measuring intracellular cytokine, RORγt in T cells, evaluating apoptosis of neutrophils. ELISA was used for measuring soluble cytokine, Western blot analysis and confocal microscopy were used for STAT3 phosphorylation and nuclear translocation.ResultsWe demonstrated synovial enrichment of Th9 cells and their positive correlation with disease activity (DAS28-ESR) in RA. Synovial IL-9 prolonged the survival of neutrophils, increased their matrix metalloprotienase-9 production and facilitated Th17 cell differentiation evidenced by induction of transcription factor RORγt and STAT3 phosphorylation. IL-9 also augmented the function of IFN-γ + and TNF-α + synovial T cells.ConclusionsWe provide evidences for critical role of IL-9 in disease pathogenesis and propose that targeting IL-9 may be an effective strategy to ameliorate synovial inflammation in RA. Inhibiting IL-9 may have wider impact on the production of pathogenic cytokines involved in autoimmune diseases including RA and may offer better control over the disease.

TNFα in the regulation of Treg and Th17 cells in rheumatoid arthritis and other autoimmune inflammatory diseases

TNFα is a principal pro-inflammatory cytokine vital for immunity to infections. However, its excessive production is involved in chronic inflammation and disease pathology in autoimmune diseases. Evidence for its pathogenic role is validated by the fact that its neutralisation by therapeutic agents in vivo is beneficial in ameliorating disease and controlling symptoms. Paradoxically, however, treatment with TNFα inhibitors can either have no clinical effects, or even exacerbate disease in some patients. The explanation for such contradictory outcomes may lay in how and which downstream signalling pathways are activated and drive disease. TNFα causes its effects by binding to either or both of two membrane-bound receptors, TNFR1 and TNFR2. Engagement of the receptors can induce cell death or cell proliferation.T cells both produce and respond to TNFα and depending on whether the cytokine is membrane-bound or soluble and the level of expression of its two receptors, the biological outcome can be distinct. In addition, polymorphisms in genes encoding TNFα and T cell signalling proteins can significantly impact the outcome of TNFα receptor engagement. Early studies revealed that effector T cells in patients with rheumatoid arthritis (RA) are hyporesponsive due to chronic exposure to TNFα. However, recent evidence indicates that the relationship between TNFα and T cell responses is complex and, at times, can be paradoxical. In addition, there is controversy as to the specific effects of TNFα on different T cell subsets. This review will summarise knowledge on how TNFα modulates T cell responses and the effect of engaging either of its two receptors. Furthermore, we discuss how such interactions can dictate the outcome of treatment with TNFα inhibitors.

Correlation Between the Expression of MicroRNA-301a-3p and the Proportion of Th17 Cells in Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation and subsequent joint destruction. Previous studies have confirmed that Th17 cells play a critical role in the pathogenesis of RA. MicroRNA (miR)-301a-3p is a regulatory factor for Th17cells differentiation that contributes to the pathogenesis of autoimmune diseases. The purposes of this study were to identify the alteration of Th17 cells and analyze the correlation between the expression of the miR-301a-3p and the proportion of Th17 cells in RA patients. The results showed that the frequency of Th17 cells and the expression of transcription factors (RORγt and STAT3) significantly increased in the peripheral blood mononuclear cells (PBMCs) from RA patients, and the associated proinflammatory cytokines were also upregulated. We also observed that the expression of protein inhibitor of activated STAT3 (PIAS3), the main cellular inhibitor of STAT3, was attenuated in RA patients and negatively correlated with the percentage of Th17 cells in RA. Interestingly, miR-301a-3p, an inhibitor of PIAS3 expression, was overexpressed in the PBMCs from RA patients and positively correlated with the frequency of Th17 cells in patients with RA. Taken together, these data indicated that miR-301a-3p and Th17 cells were augmented in peripheral blood, which may play an important role in the process of RA.

Enigma of IL-17 and Th17 Cells in Rheumatoid Arthritis and in Autoimmune Animal Models of Arthritis.

Rheumatoid arthritis (RA) is one of the most common autoimmune disorders characterized by the chronic and progressive inflammation of various organs, most notably the synovia of joints leading to joint destruction, a shorter life expectancy, and reduced quality of life. Although we have substantial information about the pathophysiology of the disease with various groups of immune cells and soluble mediators identified to participate in the pathogenesis, several aspects of the altered immune functions and regulation in RA remain controversial. Animal models are especially useful in such scenarios. Recently research focused on IL-17 and IL-17 producing cells in various inflammatory diseases such as in RA and in different rodent models of RA. These studies provided occasionally contradictory results with IL-17 being more prominent in some of the models than in others; the findings of such experimental setups were sometimes inconclusive compared to the human data. The aim of this review is to summarize briefly the recent advancements on the role of IL-17, particularly in the different rodent models of RA.

Pathogenic Transdifferentiation of Th17 Cells Contribute to Perpetuation of Rheumatoid Arthritis during Anti-TNF Treatment.

T-helper cells producing interleukin (IL)-17A and IL-17F cytokines (Th17 cells) are considered the source of autoimmunity in rheumatoid arthritis (RA). In this study, we characterized specific pathogenic features of Th17 cells in RA. By using nano-string technology, we analyzed transcription of 419 genes in the peripheral blood CCR6(+)CXCR3(-) CD4(+) cells of 14 RA patients and 6 healthy controls and identified 109 genes discriminating Th17 cells of RA patients from the controls. Th17 cells of RA patients had an aggressive pathogenic profile and in addition to signature cytokines IL-17, IL-23 and IL-21, and transcriptional regulators RAR-related orphan receptor gamma of T cells (RORγt) and Janus kinase 2 (JAK2), they produced high levels of IL-23R, C-C chemokine ligand type 20 (CCL20), granulocyte-monocyte colony-stimulating factor (GM-CSF ) and transcription factor Tbet required for synovial homing. We showed that Th17 cells are enriched with Helios-producing Foxp3- and IL2RA-deficient cells, indicating altered regulatory profile. The follicular T-helper (Tfh) cells presented a functional profile of adaptor molecules, transcriptional regulator Bcl-6 and B-cell activating cytokines IL-21, IL-31 and leukemia inhibitory factor (LIF ). We observed that anti-tumor necrosis factor (TNF) treatment had a limited effect on the transcription signature of Th17 cells. Patients in remission retained the machinery of receptors (IL-23R and IL-1R1), proinflammatory cytokines (IL-17F, IL-23, IL-21 and TNF ) and adaptor molecules (C-X-C chemokine receptor 5 [CXCR5] and cytotoxic T-lymphocyte-associated protein 4 [CTLA-4]), essential for efficient transdifferentiation and accumulation of Th17 cells. This study convincingly shows that the peripheral blood CCR6(+)CXCR3(-) CD4(+) cells of RA patients harbor pathogenic subsets of Th17 and Tfh cells, which may transdifferentiate from Tregs and contribute to perpetuation of the disease.

Altered immunoregulation in rheumatoid arthritis: the role of regulatory T cells and proinflammatory Th17 cells and therapeutic implications.

In recent years several studies investigated the role of T lymphocyte subpopulations in the pathogenesis of rheumatoid arthritis (RA). Pathogenic Th17 cells mediate pannus growth, osteoclastogenesis, and synovial neoangiogenesis; hence they are key players in the development of the disease. On the other hand, regulatory T (Treg) cells are a T cell subset whose peculiar function is to suppress autoreactive lymphocytes. The imbalance between Th17 and Treg cells has been identified as a crucial event in the pathogenesis of RA. In addition, the effects of currently employed RA therapeutic strategies on these lymphocyte subpopulations have been extensively investigated. This review article aims to discuss current knowledge on Treg and Th17 cells in RA and possible implications of their therapeutic targeting in this disorder.

S100A4 regulates the Src-tyrosine kinase dependent differentiation of Th17 cells in rheumatoid arthritis

Objectives: To evaluate the role of S100A4, a calcium-binding regulator of nonmuscle myosin assembly, for T-cell responses in rheumatoid arthritis. Methods: Arthritis was induced in the methylated bovine serum albumin (mBSA)-immunized mice lacking the entire S100A4 protein (S100A4KO) and in wild-type counterparts treated with short hairpin ribonucleic acid (shRNA)-lentiviral constructs targeting S100A4 (S100A4-shRNA). The severity of arthritis was evaluated morphologically. T-cell subsets were characterized by the expression of master transcription factors, and functionally by proliferation activity and cytokine production. The activity of the Scr-kinases Fyn and Lck was assessed by the autophosphorylation of C-terminal thyrosine and by the phosphorylation of the CD5 cytodomain. The interaction between S100A4 and the CD5 cytodomain was analysed by nuclear magnetic resonance spectrophotometry. Results: S100A4-deficient mice (S100A4KO and S100A4-shRNA) had significantly alleviated morphological signs of arthritis and joint damage. Leukocyte infiltrates in the arthritic joints of S100A4-deficient mice accumulated Foxp3+ Treg cells, while the number of RORγt+ and (pTyr705)STAT3+ cells was reduced. S100A4-deficient mice had a limited formation of Th17-cells with low retinoic acid orphan receptor gamma t (RORγt) mRNA and IL17 production in T-cell cultures. S100A4-deficient mice had a low expression and activity of T-cell receptor (TCR) inhibitor CD5 and low (pTyr705)STAT3 (signal transducer and activator of transcription 3), which led to increased (pTyr352)ZAP-70 (theta-chain associated protein kinase of 70kDa), lymphocyte proliferation and production of IL2. In vitro experiments showed that S100A4 directly binds Lck and Fyn and reciprocally regulates their kinase activity towards the CD5 cytodomain. Spectrometry demonstrates an interaction between the CD5 cytodomain and EF2-binding sites of S100A4. Conclusion: The present study demonstrates that S100A4 plays an important part in the pathogenesis of arthritis. It controls CD5-dependent differentiation of Th17 cells by regulating the activity of the Src-family kinases Lck and Fyn.

AB0022 Comparison of in Vitro Effects of Kinase and Epigenetic Inhibitors on TH17 Responses in Inflammatory Arthritis

BackgroundTh17 cells producing the proinflammatory cytokines IL-17A and IL-22 mediate multiple autoimmune conditions including inflammatory arthritides, and among these ankylosing spondylitis (AS) (1, 2). The role of Th17 cells in...

OP0195 High Sodium Intake among Smokers is A Risk Factor for ACPA Positivity in RA

BackgroundIncreased exposure to sodium chloride has been associated with an increased activation of Th17 cells and with increased risk of experimental encephalitis in mice as well as an increased T...

Circulating CD4+CD161+ T Lymphocytes Are Increased in Seropositive Arthralgia Patients but Decreased in Patients with Newly Diagnosed Rheumatoid Arthritis

Improved understanding of the immune events discriminating between seropositive arthralgia and clinical synovitis is of key importance in rheumatology research. Ample evidence suggests a role for Th17 cells in rheumatoid arthritis. We hypothesized that CD4+CD161+ cells representing Th17 lineage cells may be modulated prior to or after development of clinical synovitis. Therefore, in a cross-sectional study, we investigated the occurrence of CD4+CD161+ T-cells in seropositive arthralgia patients who are at risk for developing rheumatoid arthritis and in newly diagnosed rheumatoid arthritis patients. In a prospective study, we evaluated the effect of methotrexate treatment on circulating CD4+CD161+ T-cells. Next, we assessed if these cells can be detected at the level of the RA joints. Precursor Th17 lineage cells bearing CD161 were found to be increased in seropositive arthralgia patients. In contrast, circulating CD4+CD161+T-cells were decreased in newly diagnosed rheumatoid arthritis patients. The decrease in CD4+CD161+ T-cells correlated inversely with C-reactive protein and with the 66 swollen joint count. Methotrexate treatment led to normalization of CD4+CD161+ T-cells and reduced disease activity. CD4+CD161+ T cells were readily detected in synovial tissues from both early and late-stage rheumatoid arthritis. In addition, synovial fluid from late-stage disease was found to be enriched for CD4+CD161+ T-cells. Notably, synovial fluid accumulated CD4+CD161+T-cells showed skewing towards the Th1 phenotype as evidenced by increased interferon-γ expression. The changes in peripheral numbers of CD4+CD161+ T-cells in seropositive arthralgia and early rheumatoid arthritis and the enrichment of these cells at the level of the joint predict a role for CD4+CD161+ T-cells in the early immune events leading to clinical synovitis. Our findings may add to the development of RA prediction models and provide opportunities for early intervention.

The Microbial Capsular Polysaccharide Galactoxylomannan Inhibits IL-17A Production in Circulating T Cells from Rheumatoid Arthritis Patients

The persistence of activated T cells in rheumatoid arthritis (RA) synovium may be attributable to increased homing, increased retention or a possible imbalance between cell proliferation and programmed cell death. Induction of apoptosis may represent a potential therapeutic approach. Galactoxylomannan (GalXM) from the opportunistic fungus Cryptococcus neoformans can interact with T cells and induce T-cell apoptosis through the inhibition of CD45 phosphatase activity. The aim of this study was to determine the effect of GalXM on circulating T cells from patients with RA and the underlying mechanisms. GalXM immunomodulating effect on apoptosis and signal transduction pathway involved in IL-17A production was evaluated on T cells. RA T-cell apoptosis, higher than that of control T cells, was further increased by GalXM through induction of caspase-3 activation. Activated T cells expressing the CD45RO molecule and producing IL-17A were the main target of GalXM-induced apoptosis. GalXM induced consistent impairment of IL-17A production and inhibition of STAT3, which was hyperactivated in RA. In conclusion, GalXM triggered apoptosis of activated memory T cells and interfered with IL-17A production in RA. These data suggest therapeutic targeting of deleterious Th17 cells in RA and other autoimmune diseases.

Elevated Th22 Cells Correlated with Th17 Cells in Patients with Rheumatoid Arthritis

T-helper (Th) 22 and Th17 cells are implicated in the pathogenesis of autoimmune diseases. The roles of Th22 cells in the pathophysiology of rheumatoid arthritis (RA) remain unsettled. CD4(+)IFNγ(-)IL17(-)IL-22(+) T cells (Th22 cells), CD4(+)IFNγ(-)IL-22(-)IL17(+) T cells (pure Th17 cells), CD4(+)IL17(+) T cells (Th17 cells), and CD4(+)IFNγ(+) T cells (Th1 cells) in RA, osteoarthritis patients, and healthy controls were examined by flow cytometry. Plasma IL-22 and IL-17 levels were examined by enzyme-linked immunosorbent assay. Th22 cells, pure Th17 cells, Th17 cells, and interleukin-22 were significantly elevated in RA patients compared with osteoarthritis and healthy controls, but there were no significant differences regarding Th1 cells and interleukin-17. Th22 cells showed a positive correlation with interleukin-22 as well as pure Th17 cells or Th17 cells in RA patients. Additionally, the percentages of Th22 cells, pure Th17 cells as well as Th17 cells correlated positively with both C-reactive protein levels and 28-joints disease activity score. Together, our results indicated a possible role of Th22 pure Th17 cells and Th17 cells in RA, and blockade of the interleukin-22 may be a reasonable therapeutic strategy for RA.

Serum IL‐17 level in systemic lupus erythematosus patients

Dear Sir,In the review article titled ‘Th17 cells in rheumatoid arthritis and systemic lupus erythematosus’, Pernis highlight the recent studies that have begun elucidating the factors that regulate the development of Th17 cells and summarized the role of Th17 cells in RA and SLE. This article suggests that the newly-discovered CD4+ T cell subset, termed ‘Th17’, may provide a mechanistic explanation underlying SLE and also provide possible therapeutic targets for anti-cytokine therapy to treat this disease [1]. However, I have several concerns regarding the discussion ‘Increased levels of IL-17 have been detected in the serum of SLE patients in some studies’ [2–4]. First, a recent paper provides evidence for increased serum levels of IL-17 in SLE patients; namely, Zhao et al. Mol Biol Rep 2009 Apr 4. [5], should be mentioned. Secondly, the reference of Kurasawa et al. was incorrectly cited. In fact, their results demonstrated that IL-17 messenger RNA was expressed in unstimulated PBL and lymphocytes from the skin and lungs of SSc patients, but not in similar samples from patients with SLE. IL-17 levels were increased in the serum of SSc patients, but not in that of SLE patients.

IL-21 regulates Th17 cells in rheumatoid arthritis

IL-21 is a type I cytokine that like IL-2, IL-4, IL-7, IL-9, and IL-15 uses the common γ chain of cytokine receptor. IL-21 has been shown to regulate the function of T cells, B cells, natural killer cells, and dendritic cells in immune responses. Although activated CD4 + T cells produce IL-21, recent data suggest that novel subsets of effector T cells are the major producers in immune responses. In this study, we show that IL-21 expression correlates with the presence of Th17 cells in synovial fluid (SF) and peripheral blood in rheumatoid arthritis patients. Human CCR6+ CD4 + T cells produce high levels of both IL-21 and IL-17. Similar to mouse T cells, IL-21 auto-regulates its own production in human CD4 + T cells. IL-21 potently enhances Th17 proliferation and suppresses Foxp3 expression, leading to the expression of RORC. IL-21 is therefore an autocrine cytokine that regulates human Th17 cells in rheumatoid arthritis, and serves as a good target for treating this autoimmune disease.

Th17 cells in rheumatoid arthritis and systemic lupus erythematosus

Recent work has implicated a novel Th effector cell subset, the Th17 cell subset, in the development of both rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) because of the ability of Th17 cells to produce cytokines like IL-17 and IL-21 that can drive both inflammatory and humoral responses. In this review, we will discuss recent studies that have begun elucidating the factors that regulate the development of Th17 cells and provide a brief overview of the role of Th17 cells in RA and SLE.