Tregs In Rheumatoid Arthritis Research Articles

P180 RNA sequencing of regulatory T cells sorted from Rheumatoid Arthritis peripheral blood

Abstract Background/Aims In the presence of an inflammatory environment, regulatory T cells (Tregs) have the ability to adopt an effector T helper(Th)-like phenotype, enabling them to produce pro-inflammatory cytokines, particularly IFN-γ (resembling Th1-like Tregs) and IL-17(resembling Th17-like Tregs). This adaptability of Tregs may be driven by the increased activation of effector pathways. In order to unveil distinct gene expression patterns while simultaneously characterizing Tregs based on their phenotype, we did RNA sequencing of sorted Tregs from the peripheral blood(PB) of individuals with rheumatoid arthritis(RA), osteoarthritis(OA), and healthy controls(HC). Methods Phenotyping of Tregs, Tregs expressing CXCR3(Th1-like Treg), CCR6(Th17-like Treg) from PB and synovial fluid(SF) of RA(n = 20 each), OA(n = 20 each) and HC (n = 20) was done using flow cytometry. Cell frequencies between the groups were compared using Student t test or one-way ANOVA (Tukey's post hoc Test) as appropriate; p < 0.05 was considered as statistically significant. RNA was extracted from the sorted PB Tregs of RA, OA and HC(n = 3 each) and was sequenced using Illumina Novaseq 6000 platform. Sample clustering was done using principal component analysis generated using DeSeq2. Genes were categorized as upregulated or downregulated based on their log2 fold change cut off of 2. Significantly upregulated and downregulated differentially expressed genes (DEGs) were shortlisted using a false discovery rate(FDR) corrected p-value cut-off of ≤ 0.05. Heatmaps and volcano plots were generated using R package. Functional pathway enrichment analysis was done using GO and KEGG software. Results Proportion of Tregs in the PB of RA was significantly lower than OA and HC. This difference was not observed in the SF. Both RA PB and SF exhibited higher percentages of Th1 and Th17-like Tregs when compared to OA and HC (Table 1A).DEG analysis revealed altered gene regulation in RA Tregs compared to Tregs from HC and OA. Compared to HC, genes related to TCR signaling, cytokine signaling, and chemokine signaling pathways were enriched in RA. In contrast, compared to OA, an upregulation of pathway genes such as NR4A1(PI3K-Akt signaling), and TNFRSF1B(TNF signaling) was noted in RA. Furthermore, genes associated with Th1 differentiation and activation (IFNGR1, IL12RB1, STAT4) and genes associated with Th17 profile(RORC, STAT3, IL6R, IL17B) were upregulated in RA relative to HC and but not in OA compared to to HC.(Table 1B). Additionally, genes involved in glucose metabolism, purine metabolism, oxidative phosphorylation, and pyrimidine metabolism exhibited distinct patterns of regulation in RA. Conclusion Our Treg phenotyping data shows that there is higher conversion of Tregs into Th1 and Th17 like Tregs in RA and transcriptome data indicates cytokine(IFNγ, IL-6, IL-12 & IL-17) mediated transcriptional changes likely drove the conversion of Tregs towards Th1 and Th17 phenotype. Our data also suggests a possible metabolic re-programming of Tregs towards an inflammatory phenotype affecting its stability. Disclosure V. Kommoju: None. C. mariaselvam: None. S. Vembar: None. S. Bulusu: None. C. Kavadichanda: None. M. Thabah: None. V. Negi: None.

Augmenting regulatory T cells: new therapeutic strategy for rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune condition marked by inflammation of the joints, degradation of the articular cartilage, and bone resorption. Recent studies found the absolute and relative decreases in circulating regulatory T cells (Tregs) in RA patients. Tregs are a unique type of cells exhibiting immunosuppressive functions, known for expressing the Foxp3 gene. They are instrumental in maintaining immunological tolerance and preventing autoimmunity. Increasing the absolute number and/or enhancing the function of Tregs are effective strategies for treating RA. This article reviews the studies on the mechanisms and targeted therapies related to Tregs in RA, with a view to provide better ideas for the treatment of RA.

Negative impact of Interleukin-9 on synovial regulatory T cells in rheumatoid arthritis

In Rheumatoid Arthritis (RA), regulatory T cells (Tregs) have been found to be enriched in the synovial fluid. Despite their accumulation, they are unable to suppress synovial inflammation. Recently, we showed the synovial enrichment of interleukin-9 (IL-9) producing helper T cells and its positive correlation with disease activity. Therefore, we investigated the impact of IL-9 on synovial Tregs in RA. Here, we confirmed high synovial Tregs in RA patients, however these cells were functionally impaired in terms of suppressive cytokine production (IL-10 and TGF-β). Abrogating IL-9/ IL-9 receptor interaction could restore the suppressive cytokine production of synovial Tregs and reduce the synovial inflammatory T cells producing IFN-γ, TNF-α, IL-17. However, blocking these inflammatory cytokines failed to show any effect on IL-9 producing T cells, highlighting IL-9's hierarchy in the inflammatory network. Thus, we propose that blocking IL-9 might dampen synovial inflammation by restoring Tregs function and inhibiting inflammatory T cells.

The proportion and phenotypic changes of CD4+CD25−Foxp3+ T cells in patients with untreated rheumatoid arthritis

ObjectiveCD4+CD25+Foxp3+ regulatory T (Treg) cell-mediated immunosuppression is an essential mechanism of rheumatoid arthritis (RA). However, little is known regarding the specific role of CD4+CD25−Foxp3+ Treg cells in RA. This study aimed to investigate the frequency of circulating CD4+CD25−Foxp3+ Treg cells and their role in RA.MethodsSixty-one untreated RA patients and 40 healthy controls (HCs) were enrolled in this study. The proportion of CD4+CD25−Foxp3+ T cells and CD4+CD25+Foxp3+ Tregs; the levels of CTLA4, GITR, Helios, and ICOS; and the production of IL-17A, IFN-γ, and IL-10 were assessed by flow cytometry. The correlation of CD4+CD25–Foxp3+ T cells and CD4+CD25+Foxp3+ Tregs with the clinical indicators was conducted by Spearman correlation analysis.ResultsThe proportion of CD4+CD25–Foxp3+ T cells was elevated in RA and positively correlated with disease activity. CD4+CD25–Foxp3+ T cells expressed less Helios and produced more IFN-γ than conventional Tregs in RA. Additionally, the proportion of CD4+CD25–Foxp3+ T cells was positively correlated with DAS28 score, IgG titer, and anti-CCP titer.ConclusionsThese data indicate that CD4+CD25−Foxp3+ T cells in RA exhibit several different functional properties from conventional Tregs and are correlated with RA disease activity.

Casein Kinase II exacerbates rheumatoid arthritis via promoting Th1 and Th17 cell inflammatory responses

Objectives : Studies have demonstrated that CK2 is engaged in CD4+ T cell proliferation and activation. We investigated the potential involvement of CK2 in the pathogenesis of rheumatoid arthritis (RA). Methods Peripheral blood and synovial fluid mononuclear cells (PBMC and SFMC) of RA patients, as well as splenocytes of collagen-induced arthritis (CIA) mice were treated with different doses of CK2 inhibitor CX4945 in vitro. Then, the Th1, Th2, Th17, and Treg cell responses were analyzed. In addition, CIA mice were administrated with CX4945 via oral gavage. Accordingly, the arthritis scores, bone destruction, tissue damage, and the CD4+ T cell subsets were assessed. Results The expression of CK2 was upregulated in CD4+ T cells under RA circumstance. In vitro CX4945 treatment significantly inhibited the Th1 and Th17 cell responses, while promoted the Th2 cell responses in RA patient PBMC, SFMC and CIA mouse splenocytes, dampening IFN-γ and IL-17A production. Moreover, administration of CX4945 ameliorated the severity of arthritis in CIA mice, along with decreased Th1 and Th17 cells. However, CX4945 seemed to have minimal effect on RA Treg cells. Conclusion CK2 serves as an important regulator of the Th1 and Th17 cell axes in RA, thus contributing to the disease aggravation.

Dysfunctions, Molecular Mechanisms, and Therapeutic Strategies of Regulatory T Cells in Rheumatoid Arthritis

Regulatory T cells (Tregs) represent a distinct subpopulation of CD4+ T lymphocytes that promote immune tolerance and maintain immune system homeostasis. The dysfunction of Tregs is tightly associated with rheumatoid arthritis (RA). Although the complex pathogenic processes of RA remain unclear, studies on Tregs in RA have achieved substantial progress not only in fundamental research but also in clinical application. This review discusses the current knowledge of the characterizations, functions, and molecular mechanisms of Tregs in the pathogenesis of RA, and potential therapies for these disorders are also involved.

Single Cell RNA-Seq Analysis Identifies Differentially Expressed Genes of Treg Cell in Early Treatment-Naive Rheumatoid Arthritis By Arsenic Trioxide.

Objective: Early treatment-naïve rheumatoid arthritis (RA) has defective regulatory T (Treg) cells and increased inflammation response. In this study, we aim to illustrate the regulation of Treg cells in pathogenesis of early rheumatoid arthritis by arsenic trioxide (As2O3). Methods: We studied the effects of As2O3 on gene expression in early treatment-naïve RA Treg cells with single cell RNA-seq (scRNA-seq). Treg cells were sorted from peripheral blood mononuclear cells (PBMCs) and purified by fluorescence-activated cell sorting (FACS) and cultured with or without As2O3 (at 0.1 µM) for 24 h. Total RNA was isolated and sequenced, and functional analysis was performed against the Gene Ontology (GO) database. Results for selected genes were confirmed with RT-qPCR. Results: As2O3 exerts no significant effect on CD4+ T-cell apoptosis under physical condition, and selectively modulate CD4+ T cells toward Treg cells not Th17 cells under special polarizing stimulators. As2O3 increased the expression of 200 and reduced that of 272 genes with fold change (FC) 2.0 or greater. Several genes associated with inflammation, Treg-cell activation and differentiation as well as glucose and amino acids metabolism were among the most strongly affected genes. GO function analysis identified top ten ranked significant biological process (BPs), molecular functions (MFs), and cell components (CCs) in treatment and nontreatment Treg cells. In GO analysis, genes involved in the immunoregulation, cell apoptosis and cycle, inflammation, and cellular metabolism were enriched among the significantly affected genes. The KEGG pathway enrichment analysis identified the forkhead box O (FoxO) signal pathway, apoptosis, cytokine–cytokine receptor interaction, cell cycle, nuclear factor-kappa B (NF-κB) signaling pathway, tumor necrosis factor α (TNF-α), p53 signaling pathway, and phosphatidylinositol 3′-kinase (PI3K)-Akt signaling pathway were involved in the pathogenesis of early treatment-naïve RA. Conclusion: This is the first study investigating the genome-wide effects of As2O3 on the gene expression of treatment-naïve Treg cells. In addition to clear anti-inflammatory and immunoregulation effects, As2O3 affect amino acids and glucose metabolism in Treg cells, an observation that might be particularly important in the metabolic phenotype of treatment-naïve RA.

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.

The Proportion of Regulatory T Cells in Patients with Rheumatoid Arthritis: A Meta-Analysis.

BackgroundRegulatory T cells (Tregs) have important functions in peripheral immune tolerance. Dysfunction of Tregs is considered to be a pivotal cause of autoimmune diseases, including rheumatoid arthritis (RA). However, previous reports describing the proportion of Tregs among CD4+ T cells in RA patients were controversial because a range of markers are used to identify Tregs with little consensus. To clarify the status of Tregs in RA, we investigated the proportion of Tregs with focusing on the definitions of them.MethodsWe identified the studies reporting the proportion of Tregs in RA patients using PubMed and Google Scholar. We performed a systematic review of them and a meta-analysis to evaluate the proportion of Tregs (FOXP3-positive and/or CD25-positive) among CD4+ T cells in peripheral blood (PB) and synovial fluid (SF) of RA patients and control subjects.ResultsA total 31 studies were selected. The proportion of Tregs defined by all definitions among CD4+ T cells in PB was not significantly different between RA patients and control subjects (-0.65, [-1.30, 0.01]). Then we performed sub-analyses based on individual definitions. The proportion of Tregs defined by either CD25 or FOXP3 alone did not differ between RA patients and control subjects. The proportion of Tregs defined by both FOXP3 and CD25 was lower in RA patients than that in control subjects (-2.42 [-3.49, -1.34]). The proportion of Tregs defined by both FOXP3 and CD25 was higher in SF than that in PB among RA patients (3.27 [0.40, 6.14]).ConclusionThe status of Tregs varied according to the definition system. The proportion of Tregs defined by stricter and functionally validated methods decreased in PB and increased in SF among RA patients. If the proportion of Tregs differs in RA, accurate and functionally relevant definitions of Tregs are necessary to elucidate their status in RA.

The role of TNF-α in rheumatoid arthritis: a focus on regulatory T cells

The autoimmune disorder rheumatoid arthritis (RA) causes chronic inflammation and destruction of joints. T cells are a predominant component of the synovial environment in RA, however the functional role of these cells is not yet fully understood. This is in part due to the fact that the balance and importance of the relation of Tregs with T-effector cells in RA is still under investigation. The current treatment regimen for this debilitating disease focuses on controlling symptoms and preventing further joint damage through the use of therapies which affect different areas of the immune system at the synovium. One of the main therapies involves Tumor Necrosis Factor alpha (TNF-α) inhibitors. In the RA immune-environment, TNF-α has been shown to have an influential and extensive but as yet poorly understood effect on Treg function in vivo, and undoubtably an important role in the treatment of RA. Interestingly, the high levels of TNF-α found in RA patients appear to interfere with the mechanisms controlling the suppressive function of Tregs. Relevance for patients: This review focuses on the conflicting literature available regarding the role played by Tregs in RA and the impact of TNF-α and anti-TNF-α therapies on Tregs in this scenario. Individuals suffering from RA can benefit from better insight of the treatment mechanisms of the immunologic processes which occur throughout this disease, as current treatments for RA focus on several different areas of the immune system at the synovial compartment.

Impaired regulatory T cell function in autoimmune diseases: are microRNAs the culprits?

Impaired regulatory T cell function in autoimmune diseases: are microRNAs the culprits?

A novel upstream enhancer of FOXP3, sensitive to methylation-induced silencing, exhibits dysregulated methylation in rheumatoid arthritis Treg cells.

Treg-cell function is compromised in rheumatoid arthritis (RA). As the master regulator of Treg cells, FOXP3 controls development and suppressive function. Stable Treg-cell FOXP3 expression is epigenetically regulated; constitutive expression requires a demethylated Treg-specific demethylated region. Here, we hypothesised that methylation of the FOXP3 locus is altered in Treg cells of established RA patients. Methylation analysis of key regulatory regions in the FOXP3 locus was performed on Treg cells from RA patients and healthy controls. The FOXP3 Treg-specific demethylated region and proximal promoter displayed comparable methylation profiles in RA and healthy-donor Treg cells. We identified a novel differentially methylated region (DMR) upstream of the FOXP3 promoter, with enhancer activity sensitive to methylation-induced silencing. In RA Treg cells we observed significantly reduced DMR methylation and lower DNA methyltransferase (DNMT1/3A) expression compared with healthy Treg cells. Furthermore, DMR methylation negatively correlated with FOXP3 mRNA expression, and Treg cells isolated from rheumatoid factor negative RA patients were found to express significantly higher levels of FOXP3 than Treg cells from RhF-positive patients, with an associated decrease in DMR methylation. In conclusion, the novel DMR is involved in the regulation of Treg-cell FOXP3 expression, but this regulation is lost post-transcriptionally in RA Treg cells.

Regulatory T cells in rheumatoid arthritis showed increased plasticity toward Th17 but retained suppressive function in peripheral blood

ObjectiveRegulatory T cells (Tregs) with the plasticity of producing proinflammatory cytokine IL-17 have been demonstrated under normal and pathogenic conditions. However, it remains unclear whether IL-17-producing Tregs lose their suppressive...

CD4⁺CD25⁺/highCD127low/⁻ regulatory T cells are enriched in rheumatoid arthritis and osteoarthritis joints--analysis of frequency and phenotype in synovial membrane, synovial fluid and peripheral blood.

IntroductionCD4+CD25+/highCD127low/- regulatory T cells (Tregs) play a crucial role in maintaining peripheral tolerance. Data about the frequency of Tregs in rheumatoid arthritis (RA) are contradictory and based on the analysis of peripheral blood (PB) and synovial fluid (SF). Because Tregs exert their anti-inflammatory activity in a contact-dependent manner, the analysis of synovial membrane (SM) is crucial. Published reports regarding this matter are lacking, so we investigated the distribution and phenotype of Tregs in concurrent samples of SM, SF and PB of RA patients in comparison to those of osteoarthritis (OA) patients.MethodsTreg frequency in a total of 40 patients (18 RA and 22 OA) matched for age and sex was assessed by flow cytometry. Functional status was assessed by analysis of cell surface markers representative of activation, memory and regulation.ResultsCD4+ T cells infiltrate the SM to higher frequencies in RA joints than in OA joints (P = 0.0336). In both groups, Tregs accumulate more within the SF and SM than concurrently in PB (P < 0.0001). Relative Treg frequencies were comparable in all compartments of RA and OA, but Treg concentration was significantly higher in the SM of RA patients (P = 0.025). Both PB and SM Tregs displayed a memory phenotype (CD45RO+RA-), but significantly differed in activation status (CD69 and CD62L) and markers associated with Treg function (CD152, CD154, CD274, CD279 and GITR) with only minor differences between RA and OA.ConclusionsTreg enrichment into the joint compartment is not specific to inflammatory arthritis, as we found that it was similarly enriched in OA. RA pathophysiology might not be due to a Treg deficiency, because Treg concentration in SM was significantly higher in RA. Synovial Tregs represent a distinct phenotype and are activated effector memory cells (CD62L-CD69+), whereas peripheral Tregs are resting central memory cells (CD62L+CD69-).

Treg Cells in Rheumatoid Arthritis: An Update

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease arising from a breakdown in immunological self-tolerance, which leads to aberrant immune responses to autoantigens. Regulatory CD4(+) T-cells (Tregs) underpin one of the key mechanisms of self-tolerance and are a major focus of study in RA and other autoimmune diseases. In order to design new and improved therapies to reinstate self-tolerance, and perhaps cure disease, we need to understand the complex mechanism of action of Tregs. This review addresses recent findings in the field of Tregs in RA, with particular focus on identification of potential defects in Treg-mediated self-tolerance mechanisms present in RA patients, as well as how Tregs interact with other cells in the inflamed joints. As antigen-specific Tregs are a potential route for the reinstatement of immune tolerance, we also discuss new strategies currently being investigated which expand or induce de novo generation of Tregs.

Heat shock proteins can be targets of regulatory T cells for therapeutic intervention in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by excessive immune responses resulting in inflammation of the joints. Although current therapies can be successful in dampening inflammation, a long-lived state of tolerance is seldom achieved. Therefore, novel therapies are needed that restore and maintain tolerance in patients with RA. Targeting regulatory T cells (Tregs) is a successful strategy to achieve tolerance, as was shown in studies performed in animal models and in human clinical trials. The antigen-specificity of Tregs is crucial for their effectiveness and allows for very specific targeting of these cells. However, which antigen is suitable for autoimmune diseases such as RA, for which the autoantigens are largely unknown? Heat shock proteins (HSPs) are ubiquitously expressed and can be up-regulated during inflammation. Additionally, HSPs, or HSP-derived peptides are immunogenic and can be recognised by a variety of immune cells, including Tregs. Therefore, this review highlights the potential of HSP-specific Tregs to control inflammatory immune responses. Targeting HSP-specific Tregs in RA can be achieved via the administration of HSPs (derived peptides), thereby controlling inflammatory responses. This makes HSPs attractive candidates for therapeutic intervention in chronic autoimmune diseases, with the ultimate goal of inducing long-lasting tolerance.

The role of miR-155 in regulatory T cells and rheumatoid arthritis

Recently, various micro(mi)RNAs have been found deregulated in the setting of rheumatoid arthritis (RA), but their role in the pathogenesis of this disease remains a matter of debate. In the meanwhile, increasing evidence indicates a defective function of regulatory T cells (Tregs) in RA. This review discusses relevant studies addressing the function of Tregs and Cytotoxic T-Lymphocyte Antigen 4 in RA, provides recent data on the role of miRNAs for Tregs homeostasis, and focuses on the role of miR-155 in Tregs. In a final perspective section we discuss the potential impact of therapeutic miR-155 modulation in RA.

TRAIL Is Associated with Impaired Regulation of CD4+CD25− T Cells by Regulatory T Cells in Patients with Rheumatoid Arthritis

Thirty-five rheumatoid arthritis (RA) patients and 27 healthy volunteers were enrolled in the study. Regulatory T (Treg) cell numbers were significantly reduced in RA patients. RA Treg cells exhibited an impaired capacity to inhibit proliferation and cytokine secretion of autologous T effector (Teff) cells. However, the crossover experiments further indicated that this impaired suppression was due to resistance of Teff cells but not to an intrinsic defect of Treg cells in RA patients. RA Teff cells showed a higher expression of membrane tumor necrosis factor-related apoptosis-inducing ligand and secreted more soluble tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). TRAIL could induce apoptosis in Treg cells. Neutralization of TRAIL restored the regulation of Teff by Treg in RA patients. In summary, our data suggest that reduced peripheral Treg cell numbers and an increased resistance of Teff cells to suppression by Treg cells were present in RA patients, and TRAIL may be an underlying mechanism for the impaired regulation of Teff cells by Treg cells.

Defects in CTLA-4 are associated with abnormal regulatory T cell function in rheumatoid arthritis

The ultimate goal for the treatment of autoimmunity is to restore immunological tolerance. Regulatory T cells (Treg) play a central role in immune tolerance, and Treg functional abnormalities have been identified in different autoimmune diseases, including rheumatoid arthritis (RA). We have previously shown that natural Treg from RA patients are competent at suppressing responder T cell proliferation but not cytokine production. Here, we explore the hypothesis that this Treg defect in RA is linked with abnormalities in the expression and function of CTLA-4. We demonstrate that CTLA-4 expression on Treg from RA patients was significantly reduced compared with healthy Treg and is associated with an increased rate of CTLA-4 internalization. Regulation of T cell receptor signaling by CTLA-4 was impaired in RA Treg and associated with delayed recruitment of CTLA-4 to the immunological synapse. Artificial induction of CTLA-4 expression on RA Treg restored their suppressive capacity. Furthermore, CTLA-4 blockade impaired healthy Treg suppression of T cell IFN-gamma production, but not proliferation, thereby recapitulating the unique Treg defect in RA. Our results suggest that defects in CTLA-4 could contribute to abnormal Treg function in RA and may represent a target for therapy for inducing long-lasting remission.