The Plasticity of Th17 Cells in the Pathogenesis of Rheumatoid Arthritis

Association between iridocyclitis and immune-related disease: A 2-sample Mendelian randomization study

The genetic basis of iridocyclitis, an inflammatory eye disease, remains poorly understood, particularly in relation to autoimmune diseases. This study aimed to explore the causal associations between 6 immune-related diseases and iridocyclitis using Mendelian randomization (MR). A total of 230 single nucleotide polymorphisms (SNPs) significantly associated with systemic lupus erythematosus, ankylosing spondylitis (AS), rheumatoid arthritis (RA), Graves disease (GD), Crohn disease (CD), and allergic contact dermatitis were identified based on stringent MR assumptions. These SNPs served as instrumental variables to estimate the causal effect of each autoimmune disease on iridocyclitis risk. The analysis utilized the inverse variance weighted method, complemented by sensitivity analyses including MR-Egger regression and leave-one-out testing to assess pleiotropy and robustness. The MR analysis revealed significant associations between genetically predicted AS (odds ratio [OR]: 1.544, 95% confidence interval [CI]: 1.494-1.595, P = 1.99 × 10-226), RA (OR: 1.207, 95% CI: 1.052-1.385, P = .003), and CD (OR: 1.654, 95% CI: 1.263-2.166, P = 2.54 × 10⁻⁶) with an increased risk of iridocyclitis. Conversely, higher genetically predicted GD was associated with a decreased risk of iridocyclitis (OR: 0.763, 95% CI: 0.674-0.865, P = .0002). Although systemic lupus erythematosus and allergic contact dermatitis appeared to have a protective effect, these results were not statistically significant, and no causal relationship could be established. Heterogeneity was observed among the SNPs, but no significant horizontal pleiotropy was detected. This study identifies potential genetic links between AS, RA, CD, GD, and the risk of iridocyclitis, providing new insights into the genetic underpinnings of this eye disease. The results support the need for further investigation into the genetic and molecular mechanisms underlying these associations.

Evaluation of the Anti-Inflammatory/Immunomodulatory Effect of Teucrium montanum L. Extract in Collagen-Induced Arthritis in Rats

The anti-inflammatory/immunomodulatory effects of Teucrium montanum L. (TM), a plant distributed in the Mediterranean region, have been insufficiently examined. The effects of the TM ethanol extract were tested in a rat collagen-induced arthritis (CIA) model of rheumatoid arthritis. LC-MS was used for the phytochemical analysis of the TM extract. Dark Agouti rats were immunized with bovine type II collagen (CII) in incomplete Freund's adjuvant for CIA, and treated with 100 or 200 mg/kg of TM extract daily via oral administration. Clinical and histopathological evaluations and a flow cytometric analysis of the phenotypic and functional characteristics of splenocytes and draining lymph node cells were performed. The cytokines in the paw tissue culture supernatants and anti-CII antibodies in serum were determined by ELISA. The TM extract, with the dominant components verbascoside and luteolin 7-O-rutinoside, reduced the arthritic score and ankle joint inflammation in CIA rats, promoted the antioxidant profile in serum, and lowered pro-inflammatory TNF-α, IL-6 and IL-1β production. It suppressed the activation status of CD11b+ cells by lowering CD86, MHCII and TLR-4 expression, and promoted the Th17/T regulatory cell (Tregs) balance towards Tregs. A lower frequency of B cells was accompanied by a lower level of anti-CII antibodies in treated rats. These findings imply the favorable effect of TM extract on the clinical presentation of CIA, suggesting its anti-inflammatory/immunomodulatory action and potential therapeutic effect.

Mechanistic insights into anti-inflammatory and immunosuppressive effects of plant secondary metabolites and their therapeutic potential for rheumatoid arthritis

The anti-inflammatory and immunosuppressive activities of plant secondary metabolites are due to their diverse mechanisms of action against multifarious molecular targets such as modulation of the complex immune system associated with rheumatoid arthritis (RA). This review discussed and critically analyzed the potent anti-inflammatory and immunosuppressive effects of several phytochemicals and their underlying mechanisms in association with RA in experimental studies, including preliminary clinical studies of some of them. A wide range of phytochemicals including phenols, flavonoids, chalcones, xanthones, terpenoids, alkaloids, and glycosides have shown significant immunosuppressive and anti-inflammatory activities in experimental RA models and a few have undergone clinical trials for their efficacy and safety in reducing RA symptoms and improve patient outcomes. These phytochemicals have potential as safer alternatives to the existing drugs in the management of RA, which possess a wide range of serious side effects. Sufficient preclinical studies on safety and efficacy of these phytochemicals must be performed prior to proper clinical studies. Further studies are needed to address the barriers that have so far limited their human use before the therapeutic potential of these plant-based chemicals as anti-arthritic agents in the treatment of RA is fully realized.

Autoimmune response after SARS-CoV-2 infection and SARS-CoV-2 vaccines

The complicated relationships between autoimmunity, COVID-19, and COVID-19 vaccinations are described, giving insight into their intricacies. Antinuclear antibodies (ANA), anti-Ro/SSA, rheumatoid factor, lupus anticoagulant, and antibodies against interferon (IFN)-I have all been consistently found in COVID-19 patients, indicating a high prevalence of autoimmune reactions following viral exposure. Furthermore, the discovery of human proteins with structural similarities to SARS-CoV-2 peptides as possible autoantigens highlights the complex interplay between the virus and the immune system in initiating autoimmunity. An updated summary of the current status of COVID-19 vaccines is presented. We present probable pathways underpinning the genesis of COVID-19 autoimmunity, such as bystander activation caused by hyperinflammatory conditions, viral persistence, and the creation of neutrophil extracellular traps. These pathways provide important insights into the development of autoimmune-related symptoms ranging from organ-specific to systemic autoimmune and inflammatory illnesses, demonstrating the wide influence of COVID-19 on the immune system.

Deep Immunophenotyping of Circulating T and B Cells in Relapsing Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD) is a complex systemic inflammatory disorder, categorized as an 'IL-1 driven' inflammasomapathy. Despite this, the interaction between T and B cells remains poorly understood. We conducted a study, enrolling 7 patients with relapsing AOSD and 15 healthy control subjects, utilizing deep flow cytometry analysis to examine peripheral blood T- and B-cell subsets. T-cell and B-cell subsets were significantly altered in patients with AOSD. Within CD4+ T cells, Th2 cells were decreased. Additionally, Th17 cell and follicular Th cell subsets were altered within CD45RA-CD62L+ and CD45RA-CD62L- Th cells in patients with AOSD compared to healthy controls. We identified changes in CD8+ T cell maturation and 'polarization' in AOSD patients, with an elevated presence of the TEMRA CD8+ T cell subset. Furthermore, the percentage of Tc1 cells was decreased, while the frequency of CCR6-CXCR3- Tc2 cells was elevated. Finally, we determined that the frequency of CD5+CD27- B cells was dramatically decreased in patients with AOSD compared to healthy controls. Further investigations on a large group of patients with AOSD are required to evaluate these adaptive immunity cells in the disease pathogenesis.

Proteomics profiling of CD4 + T-cell-derived exosomes from patients with rheumatoid arthritis

OBJECTIVES

Our study profiled the CD4 + T-cell-derived exosomes from patients with rheumatoid arthritis (RA) using proteomics.

METHODS

Proteomic analysis of CD4 + T-cell-derived exosomes was performed by tandem mass tags (TMT) combined with LC-MS/MS. We validated the most significantly upregulated and downregulated proteins using ELISA and WB.

RESULTS

The proteomic results showed that there were 3 upregulated differentially expressed proteins and 31 downregulated differentially expressed proteins in the RA group. The results indicated that dihydropyrimidinase-related protein 3 (DPYSL3) was significantly upregulated in CD4 + T-cell-derived exosomes, whereas proteasome activator complex subunit 1 (PSME1) was significantly downregulated in the RA group. Bioinformatics analysis showed that proteins were enriched in "positive regulation of gene expression", "antigen processing and presentation", "acute-phase response" and "PI3K-AKT signaling" pathways. ELISA verified that compared to the control group, the RA group showed significant upregulation of DPYSL3, and downregulation of PSME1 in CD4 + T-cell-derived exosomes.

CONCLUSIONS

The proteomic analysis results of CD4 + T-cell-derived exosomes from patients with RA suggest that these differentially expressed proteins may be involved in RA pathogenesis. DPYSL3 and PSME1 may become useful biomarkers for RA.

Gene regulatory network study of rheumatoid arthritis in single-cell chromatin landscapes of peripheral blood mononuclear cells

OBJECTIVES

Assays for transposase-accessible chromatin with single-cell sequencing (scATAC-seq) contribute to the progress in epigenetic studies. The purpose of our project was to discover the transcription factors (TFs) that were involved in the pathogenesis of rheumatoid arthritis (RA) at a single-cell resolution using epigenetic technology.

METHODS

Peripheral blood mononuclear cells of seven RA patients and seven natural controls were extracted nuclei suspensions for library construction. Subsequently, scATAC-seq was performed to generate a high-resolution map of active regulatory DNA for bioinformatics analysis.

RESULTS

We obtained 22 accessible chromatin patterns. Then, 10 key TFs were involved in RA pathogenesis by regulating the activity of mitogen-activated protein kinase. Consequently, two genes (PTPRC and SPAG9) regulated by 10 key TFs were found, which may be associated with RA disease pathogenesis, and these TFs were obviously enriched in RA patients (P < .05, fold change value > 1.2). With further quantitative polymerase chain reaction validation on PTPRC and SPAG9 in monocytes, we found differential expression of these two genes, which were regulated by eight TFs [ZNF384, HNF1B, DMRTA2, MEF2A, NFE2L1, CREB3L4 (var. 2), FOSL2::JUNB (var. 2), and MEF2B], showing highly accessible binding sites in RA patients.

CONCLUSIONS

These findings demonstrate the value of using scATAC-seq to reveal transcriptional regulatory variation in RA-derived peripheral blood mononuclear cells, providing insights into therapy from an epigenetic perspective.

Role of Interleukin-36 in inflammatory joint diseases

Interleukin (IL)-36 is a family of cytokines that belongs to the larger IL-1 superfamily. IL-36 agonist/antagonist binds to the interleukin-36 receptor involving in physiological inflammation regulation and pathogenesis of many inflammatory diseases. In inflammatory joint diseases, the expression of IL-36 changes, and some studies have initially explored the role of IL-36 in these diseases. In psoriatic arthritis, IL-36 signal mediates plasma cell and fibroblast-like synoviocyte crosstalk presenting IL-36 agonist/antagonist imbalance. In rheumatoid arthritis, IL-36 agonists induce fibroblast-like synoviocyte to produce pro-inflammatory factors, while IL-36 antagonist deficiency leads to lesion progression. In osteoarthritis, IL-36 agonists induce chondrocytes to produce catabolic enzymes and pro-inflammatory factors. This article reviews the expression and function of IL-36 in different inflammatory joint diseases to provide a reference for revealing their pathogenic mechanisms and discovering therapeutic targets.

Patched 1 and C-C Motif Chemokine Receptor 6 Distinguish Heterogeneous T Helper 17 Subsets in Colitic Lamina Propria

T helper 17 (Th17) cells contribute to the pathogenesis of inflammatory bowel diseases (IBD). However, their heterogeneity and regulatory mechanisms in IBD are not completely disclosed. A mouse colitis model was established. Th17 cells were enriched from the mesenteric lymph nodes (mLN) and lamina propria (LP). The phenotypes and functions of Th17 subsets were analyzed by flow cytometry, Immunoblotting, and real-time RT-PCR. The contributions of the Th17 subsets to colitis pathogenesis were evaluated by histology, ELISA, and flow cytometry after adoptive transfer. Smoothened (SMO), GLI family zinc finger 1 (Gli1), and GLI family zinc finger 3 (Gli3) were markedly up-regulated while Patched 1 (PTCH1) was down-regulated in LP Th17 cells in colitic lamina propria. Based on the expression of PTCH1 and C-C motif chemokine receptor 6 (CCR6), LP Th17 cells were divided into a PTCH1^lowCCR6^low Th17 subset and a PTCH1^highCCR6^high Th17 subset. The former expressed higher T-bet, IFN-γ, TNF-α, IL-1β, and GM-CSF but lower IL-17A, IL-22, IL-17F, and Gli3 than the latter. The PTCH1^highCCR6^high Th17 subset was more resistant to polarization towards T helper 1 (Th1) than the PTCH1^lowCCR6^low Th17 subset. Moreover, the PTCH1^highCCR6^high Th17 subset was more competent to maintain Th17 identity. The PTCH1^highCCR6^high Th17 subset induced less severe colitis than the PTCH1^lowCCR6^low Th17 subset. PTCH1^highCCR6^high Th17 cells are Th17 cells whereas PTCH1^lowCCR6^low Th17 cells are Th1-like Th17 cells. Our study deepens the understanding of Th17 heterogeneity and plasticity in colitis.

The Effect of PEGylated Graphene Oxide Nanoparticles on the Th17-Polarization of Activated T Helpers

We investigated the direct effect of PEGylated graphene oxide (P-GO) nanoparticles on the differentiation, viability, and cytokine profile of activated T helper type 17 (Th17) in vitro. The subject of the study were cultures of "naive" T-helpers (CD4+) isolated by immunomagnetic separation and polarized into the Th17 phenotype with a TCR activator and cytokines. It was found that P-GO at low concentrations (5 µg/mL) had no effect on the parameters studied. The presence of high concentrations of P-GO in T-helper cultures (25 μg/mL) did not affect the number and viability of these cells. However, the percentage of proliferating T-helpers in these cultures was reduced. GO nanoparticles modified with linear polyethylene glycol (PEG) significantly increased the percentage of Th17/22 cells in cultures of Th17-polarized T helpers and the production of IFN-γ, whereas those modified with branched PEG suppressed the synthesis of IL-17. Thus, a low concentration of PEGylated GO nanoparticles (5 μg/mL), in contrast to a concentration of 25 μg/mL, has no effect on the Th17-polarization of T helpers, allowing their further use for in-depth studies of the functions of T lymphocytes and other immune cells. Overall, we have studied for the first time the direct effect of P-GO nanoparticles on the conversion of T helper cells to the Th17 phenotype.

Bifidobacterium breve CCFM1078 Alleviates Collagen-Induced Arthritis in Rats via Modulating the Gut Microbiota and Repairing the Intestinal Barrier Damage

This study focused on the effects of Bifidobacterium breve CCFM1078 on the intestinal barrier and systemic inflammation of collagen-induced arthritis (CIA) rats. Female rats were divided into three groups with daily intragastric administration of either saline (control group and model group) or B. breve CCFM1078 (CCFM1078 group, 3 × 10⁹cfu/rat per day) for 5 weeks. In the Model and CCFM1078 groups, arthritis was induced by subcutaneous collagen injection. We found that B. breve CCFM1078 can repair the intestinal barrier, reduce LPS translocation, regulate gut microbiota composition, and increase short-chain fatty acids in the intestine. Then, it can reduce pro-inflammatory cytokines release, adjust immune dysfunction, and inhibit TLR4-MyD88-dependent pathways and downstream inflammatory pathways to alleviate joint inflammation in CIA rats. These findings suggest that B. breve CCFM1078 may alleviate joint inflammation by adjusting the profile of gut microbiota and enhancing the intestinal barrier.

Features of Peripheral Blood Th-Cell Subset Composition and Serum Cytokine Level in Patients with Activity-Driven Ankylosing Spondylitis

Th cells may exhibit pathological activity depending on the regulatory and functional signals sensed under a wide range of immunopathological conditions, including ankylosing spondylitis (AS). The relationship between Th cells and cytokines is important for diagnoses and for determining treatment. Accordingly, the aim of this study was to investigate the relationship between Th-cell subset composition and serum cytokine profile for patients with activity-driven AS. In our study, patients were divided into two groups according to disease activity: low-activity AS (ASDAS-CRP < 2.1) and high-activity AS (ASDAS-CRP > 2.1). The peripheral blood Th cell subset composition was studied by flow cytometry. Using multiplex analysis, serum cytokine levels were quantified and investigated. It was found that only patients with high-activity AS had reduced central memory (CM) Th1 cells (p = 0.035) but elevated numbers of CM (p = 0.014) and effector memory (EM) Th2 cells (p < 0.001). However, no activity-driven change in the Th17 cell subset composition was observed in AS patients. Moreover, low-AS activity patients had increased numbers of Tfh17 EM cells (p < 0.001), whereas high-AS activity was associated with elevated Tfh2 EM level (p = 0.031). The serum cytokine profiles in AS patients demonstrated that cues stimulating cellular immunity were increased, but patients with high-AS activity reveled increased IL-5 level (p = 0.017). Analyzing the data obtained from AS patients allowed us to conclude that Th cell subset differentiation was mainly affected during the CM stage and characterized the IL-23/IL-17 regulatory axis, whereas increased humoral immunity was observed in the high-AS activity group.

NKB cells: A double-edged sword against inflammatory diseases

Interferon-γ (IFN-γ)-producing natural killer (NK) cells and innate lymphoid cells (ILCs) activate the adaptive system’s B and T cells in response to pathogenic invasion; however, how these cells are activated during infections is not yet fully understood. In recent years, a new lymphocyte population referred to as “natural killer-like B (NKB) cells”, expressing the characteristic markers of innate NK cells and adaptive B cells, has been identified in both the spleen and mesenteric lymph nodes during infectious and inflammatory pathologies. NKB cells produce IL-18 and IL-12 cytokines during the early phases of microbial infection, differentiating them from conventional NK and B cells. Emerging evidence indicates that NKB cells play key roles in clearing microbial infections. In addition, NKB cells contribute to inflammatory responses during infectious and inflammatory diseases. Hence, the role of NKB cells in disease pathogenesis merits further study. An in-depth understanding of the phenotypic, effector, and functional properties of NKB cells may pave the way for the development of improved vaccines and therapeutics for infectious and inflammatory diseases.

GPR15 expressed in T lymphocytes from RA patients is involved in leukocyte chemotaxis to the synovium

The rheumatoid arthritis (RA) inflammatory process occurs in the joints where immune cells are attracted into the synovium to promote remodeling and tissue damage. GPR15 is a G protein-coupled receptor (GPCR) located on chromosome 3 and has similarity in its sequence with chemokine receptors. Recent evidence indicates that GPR15 may be associated with modulation of the chronic inflammatory response. We evaluated the expression of GPR15 and GPR15L in blood and synovial tissue samples from RA patients, as well as to perform a functional migration assay in response to GPR15L. The expression of GPR15 and c10orf99/gpr15l mRNA was analyzed by RT-qPCR. Samples of synovial fluid and peripheral blood were analyzed for CD45+CD3+CD4+GPR15+ and CD45+CD3+CD8+GPR15+ T cell frequency comparing RA patients versus control subjects by flow cytometry. Migration assays were performed using PBMCs isolated from these individuals in response to the synthetic GPR15 ligand. Statistical analysis included Kruskal-Wallis test, T-test, or Mann-Whitney U test, according to data distribution. A higher expression in the mRNA for GPR15 was identified in early RA subjects. The frequencies of CD4+/CD8+ GPR15+ T lymphocytes are higher in RA patients comparing with healthy subjects. Also, the frequency CD4+/CD8+ GPR15+ T lymphocytes are higher in synovial fluid of established RA patients comparing with OA patients. GPR15 and GPR15L are present in the synovial tissue of RA patients and GPR15L promotes migration of PBMCs from RA patients and healthy subjects. Our results suggest that GPR15/GPR15L have a pathogenic role in RA and their antagonizing could be a therapeutic approach in RA.

The Prescription of Chinese Herbal Medicine and Risk of Endometriosis in Women with Rheumatoid Arthritis: A Population-Based Cohort Study

Purpose

The systemic inflammation is believed to provide an outline of the association between rheumatoid arthritis (RA) and endometriosis. This retrospective cohort study aimed to explore the association of Chinese herbal medicine (CHM) use with the prevention of endometriosis onset in women diagnosed with RA.

Methods

We utilized the claims data from the National Health Insurance of Taiwan from 2000 to 2009 and excluded individuals diagnosed with endometriosis before being diagnosed with RA, using age at clinical diagnosis. After selection and propensity-score matching, a total of 5992 females aged ≧20 years old and with newly diagnosed RA but without endometriosis at baseline were included, which contained 2996 CHM users and 2996 non-CHM users. All of them were followed until the end of 2013 to measure the incidence of endometriosis.

Results

During the study period, we noticed that CHM users had a substantially lower incidence of endometriosis compared to non-CHM users (2.54 vs 5.19 per 1000 person-years). Use of CHM correlated significantly with a lower endometriosis likelihood even after adjusting for potential covariates, with the adjusted hazard ratio of 0.47 (95% confidence interval, 0.35–0.65). A longer duration of CHM use was associated with a reduction in endometriosis risk, especially in those using CHM for more than 730 days. Uses of several herbal products may be associated with a lower risk of endometriosis, like Ge-Gen, Da-Huang, Huang-Qin, Ye-Jiao-Teng, Chuan-Niu-Xi, Shu-Jing-Huo-Xue-Tang, Du-Huo-Ji-Sheng-Tang, Ge-Gen-Tang, Shao-Yao-Gan-Cao-Tang, Ping-Wei-San, Gan-Lu-Yin, and Dang-Gui-Nian-Tong-Tang.

Conclusion

Taken together, adding CHM to conventional therapy may reduce the incidence of endometriosis in women with RA. The therapeutic mechanisms and safety of these natural products may be a direction for future clinical studies.

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.

Vitamin D, Th17 Lymphocytes, and Breast Cancer

Simple Summary

The effect of vitamin D₃ on the development of breast cancer (favorable, ineffective, or even unfavorable) depends on many factors, such as age, menopausal status, or obesity. The immunomodulatory effect of vitamin D may be unfavorable in case of breast cancer progression. The effect of vitamin D on Th17 cells may depend on disease type and patients’ age. Our goal was to summarize the data available and to find indications of vitamin D treatment failure or success. Therefore, in this review, we present data describing the effects of vitamin D₃ on Th17 cells, mainly in breast cancer.

Abstract

Vitamin D₃, which is well known to maintain calcium homeostasis, plays an important role in various cellular processes. It regulates the proliferation and differentiation of several normal cells, including immune and neoplastic cells, influences the cell cycle, and stimulates cell maturation and apoptosis through a mechanism dependent on the vitamin D receptor. The involvement of vitamin D₃ in breast cancer development has been observed in numerous clinical studies. However, not all studies support the protective effect of vitamin D₃ against the development of this condition. Furthermore, animal studies have revealed that calcitriol or its analogs may stimulate tumor growth or metastasis in some breast cancer models. It has been postulated that the effect of vitamin D₃ on T helper (Th) 17 lymphocytes is one of the mechanisms promoting metastasis in these murine models. Herein we present a literature review on the existing data according to the interplay between vitamin D, Th17 cell and breast cancer. We also discuss the effects of this vitamin on Th17 lymphocytes in various disease entities known to date, due to the scarcity of scientific data on Th17 lymphocytes and breast cancer. The presented data indicate that the effect of vitamin D₃ on breast cancer development depends on many factors, such as age, menopausal status, or obesity. According to that, more extensive clinical trials and studies are needed to assess the importance of vitamin D in breast cancer, especially when no correlations seem to be obvious.

Gut Microbiota Structure and Metabolites, Before and After Treatment in Early Rheumatoid Arthritis Patients: A Pilot Study

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. Modifications of gut microbiota seem to be associated with the disease, but the impact of gut microbiota on therapies’ outcome remains unclear. A role of T cells in RA pathogenesis has been addressed, particularly on the Th17/Treg cells balance. Our study aimed to evaluate in early RA (ERA) patients compared to a control group, fecal gut microbiota composition, short-chain fatty acids concentrations, and the levels of circulating Th17/Treg and their own cytokines, before and after 3 months of standard treatment (Methotrexate (MTX) plus glucocorticoids). Fecal microbiota characterization was carried out on 19 ERA patients and 20 controls matched for sex and age. Significant decreased biodiversity levels, and a partition on the base of the microbiota composition, between the ERA patients at baseline compared to controls, were observed. The co-occurrent analysis of interactions revealed a characteristic clustered structure of the microbial network in controls that is lost in ERA patients where an altered connection between microbes and clinical parameters/metabolites has been reported. Microbial markers such as Acetanaerobacterium elongatum, Cristiansella massiliensis, and Gracilibacter thermotolerans resulted significantly enriched in control group while the species Blautia gnavus emerged to be more abundant in ERA patients. Our results showed an alteration in Th17/Treg balance with higher Th17 levels and lower Treg levels in ERA group respect to control at baseline, those data improved after therapy. Treatment administration and the achievement of a low disease activity/remission appear to exert a positive pressure on the structure of intestinal microbiota with the consequent restoration of biodiversity, of the structure of microbial network, and of the abundance of taxa that became closer to those presented by the subject without the disease. We also found an association between Blautia gnavus and ERA patients characterized by a significant reduction of propionic acid level. Furthermore significant differences highlighted at baseline among controls and ERA patients are no more evident after treatment. These data corroborate the role played by gut microbiota in the disease and suggest that therapy aimed to restore gut microbiota would improve treatment outcome.

Distinct molecular and immune hallmarks of inflammatory arthritis induced by immune checkpoint inhibitors for cancer therapy

Immune checkpoint inhibitors are associated with immune-related adverse events (irAEs), including arthritis (arthritis-irAE). Management of arthritis-irAE is challenging because immunomodulatory therapy for arthritis should not impede antitumor immunity. Understanding of the mechanisms of arthritis-irAE is critical to overcome this challenge, but the pathophysiology remains unknown. Here, we comprehensively analyze peripheral blood and/or synovial fluid samples from 20 patients with arthritis-irAE, and unmask a prominent Th1-CD8+ T cell axis in both blood and inflamed joints. CX3CR1hi CD8+ T cells in blood and CXCR3hi CD8+ T cells in synovial fluid, the most clonally expanded T cells, significantly share TCR repertoires. The migration of blood CX3CR1hi CD8+ T cells into joints is possibly mediated by CXCL9/10/11/16 expressed by myeloid cells. Furthermore, arthritis after combined CTLA-4 and PD-1 inhibitor therapy preferentially has enhanced Th17 and transient Th1/Th17 cell signatures. Our data provide insights into the mechanisms, predictive biomarkers, and therapeutic targets for arthritis-irAE.

Plasma interleukin-23 and circulating IL-17A+IFNγ+ ex-Th17 cells predict opposing outcomes of anti-TNF therapy in rheumatoid arthritis

OBJECTIVES

TNF-α inhibitors are widely used in rheumatoid arthritis (RA) with varying success. Response to TNF-α inhibition may reflect the evolution of rheumatoid inflammation through fluctuating stages of TNF-α dependence. Our aim was to assess plasma concentrations of Th-17-related cytokines and the presence of circulating effector T-cells to identify predictors of response to TNF-α inhibitors.

METHODS

Ninety-three people with RA were seen prior to and 4-6 months after commencing etanercept or adalimumab. Plasma concentrations of Th17-related cytokines, circulating effector T-cells, their production of relevant transcription factors and intracellular cytokines were measured at baseline. EULAR response criteria were used to define poor (ΔDAS28 ≤ 1.2 and/or DAS28 > 3.2) and good (ΔDAS28 > 1.2 and DAS28 ≤ 3.2) responders. Multivariate logistic regression was used to identify predictors of response.

RESULTS

Participants with plasma IL-23 present at baseline were more likely to be poor responders [15/20 (75%) of IL-23⁺ versus 36/73 (49.3%) of IL-23^-; p = 0.041]. While frequencies of Th1, Th17, ex-Th17 and T_reg cell populations were similar between good and poor responders to anti-TNF therapy, IL-17A⁺IFNγ⁺ ex-Th17 cells were more prevalent in good responders (0.83% of ex-T_H17 cells) compared to poor responders (0.24% of ex-Th17 cells), p = 0.023. Both plasma IL-23 cytokine status (OR = 0.17 (95% CI 0.04-0.73)) and IL-17A⁺IFNγ⁺ ex-Th17 cell frequency (OR = 1.64 (95% CI 1.06 to 2.54)) were independently associated with a good response to anti-TNF therapy. Receiver operator characteristic (ROC) analysis, including both parameters, demonstrated an area under the ROC curve (AUC) of 0.70 (95% CI 0.60-0.82; p = 0.001).

CONCLUSIONS

Plasma IL-23 and circulating IL-17A⁺IFNγ⁺ ex-Th17 cells are independently associated with response to anti-TNF therapy. In combination, plasma IL-23 and circulating IL-17A⁺IFNγ⁺ ex-Th17 cells provide additive value to the prediction of response to anti-TNF therapy in RA.

Toll-like receptor-7 activation in CD8+ T cells modulates inflammatory mediators in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder of unknown etiology with aberrant immunological responses leading to inflammation, swelling and pain of the joints. CD8⁺ T cells have been known to be one of the major immune modulators in the progression of RA and the presence of toll-like receptors (TLRs) on these cells further accentuate their role in RA. Herein, we report an increased expression of TLR7 in the endosomes of CD8⁺ T cells of RA patients correlating with disease severity. The stimulation of TLR7 with Imiquimod (IMQ) in these CD8⁺ T cells drives the signalling cascade via NFkB and pERK activation and hence an increase in the mRNA transcripts of signature cytokines and cytolytic enzymes. However, a parallel synthesis of Tristetraprolin (TTP), an mRNA destabilizing protein prevents the translation of the mRNA transcripts, leading to a rapid degeneration of the target mRNA. We thus report that a direct TLR7 ligation by its agonist increases cytokine transcript signature but not an equivalent protein surge.

High dietary salt intake activates inflammatory cascades via Th17 immune cells: impact on health and diseases

The incidence of immune-mediated inflammatory diseases (IMIDs) is on the rise. A high salt content in the diet was found to play a crucial role in mediating IMIDs. It was demonstrated that increased salt concentration favors the differentiation of CD4+ cells to pathogenic Th17 cells, which predispose to several inflammatory diseases by modulating the immunological milieu. In auto-immune diseases increased salt concentration causes stable induction of Th17 cells. In cancer, increased salt concentration triggers chronic inflammation and increases vascular endothelial growth factor levels. Salt-mediated proliferation of Th17 cells has been found to reduce nitric oxide production in the endothelial cells, leading to hypertension. Increased salt concentration was found to alter the intestinal flora, which favors local inflammation. This review attempts to explain the role of high salt concentration and its molecular pathways in causing IMIDs.

Deficiency of protease-activated receptor (PAR) 1 and PAR2 exacerbates collagen-induced arthritis in mice via differing mechanisms

OBJECTIVES

Protease-activated receptor (PAR) 1 and PAR2 have been implicated in RA, however their exact role is unclear. Here, we detailed the mechanistic impact of these receptors on the onset and development of inflammatory arthritis in murine CIA and antigen-induced arthritis (AIA) models.

METHODS

CIA or AIA was induced in PAR1 or PAR2 gene knockout (KO) and matched wild type mice. The onset and development of arthritis was monitored clinically and histologically. Immune cells, cytokines and MMPs were detected by ELISA, zymography, flow cytometry, western blot or immunohistochemistry.

RESULTS

In CIA, PAR1KO and PAR2KO exacerbated arthritis, in opposition to their effects in AIA. These deficient mice had high plasma levels of IL-17, IFN-γ, TGF-β1 and MMP-13, and lower levels of TNF-α; T cells and B cells were higher in both KO spleen and thymus, and myeloid-derived suppressor cells were lower only in PAR1KO spleen, when compared with wild type cells. Th1, Th2 and Th17 cells were lower in PAR1KO spleens cells, whereas Th1 and Th2 cells were lower and Th17 cells higher in both KO thymus cells, when compared with wild type cells. PAR1KO synovial fibroblasts proliferated faster and produced the most abundant MMP-9 amongst three type cells in the control, lipopolysaccharides or TNF stimulated conditions.

CONCLUSION

This is the first study demonstrated that deficiency of PAR1 or PAR2 aggravates inflammatory arthritis in CIA. Furthermore, the protective functions of PAR1 and PAR2 in CIA likely occur via differing mechanisms involving immune cell differentiation and cytokines/MMPs.

Activated, Pro-Inflammatory Th1, Th17, and Memory CD4+ T Cells and B Cells Are Involved in Delayed-Type Hypersensitivity Arthritis (DTHA) Inflammation and Paw Swelling in Mice

Delayed-type hypersensitivity arthritis (DTHA) is a recently established experimental model of rheumatoid arthritis (RA) in mice with pharmacological values. Despite an indispensable role of CD4+ T cells in inducing DTHA, a potential role for CD4+ T cell subsets is lacking. Here we have quantified CD4+ subsets during DTHA development and found that levels of activated, pro-inflammatory Th1, Th17, and memory CD4+ T cells in draining lymph nodes were increased with differential dynamic patterns after DTHA induction. Moreover, according to B-cell depletion experiments, it has been suggested that this cell type is not involved in DTHA. We show that DTHA is associated with increased levels of B cells in draining lymph nodes accompanied by increased levels of circulating IgG. Finally, using the anti-rheumatoid agents, methotrexate (MTX) and the anti-inflammatory drug dexamethasone (DEX), we show that MTX and DEX differentially suppressed DTHA-induced paw swelling and inflammation. The effects of MTX and DEX coincided with differential regulation of levels of Th1, Th17, and memory T cells as well as B cells. Our results implicate Th1, Th17, and memory T cells, together with activated B cells, to be involved and required for DTHA-induced paw swelling and inflammation.

Mechanism of Immunoregulatory Properties of Vasoactive Intestinal Peptide in the K/BxN Mice Model of Autoimmune Arthritis

The K/BxN mouse model of rheumatoid arthritis (RA) closely resembles the human disease. In this model, arthritis results from activation of autoreactive KRN T cells recognizing the glycolytic enzyme glucose-6-phosphate isomerase (GPI) autoantigen, which provides help to GPI-specific B cells, resulting in the production of pathogenic anti-GPI antibodies that ultimately leads to arthritis symptoms from 4 weeks of age. Vasoactive intestinal peptide (VIP) is a neuropeptide broadly distributed in the central and peripheral nervous system that is also expressed in lymphocytes and other immune cell types. VIP is a modulator of innate and adaptive immunity, showing anti-inflammatory and immunoregulatory properties. Basically, this neuropeptide promotes a shift in the Th1/Th2 balance and enhances dedifferentiation of T regulatory cells (Treg). It has demonstrated its therapeutic effects on the collagen-induced arthritis (CIA) mouse model of RA. In the present hypothesis and theory article, we propose that the immunoregulatory properties of VIP may be due likely to the inhibition of T cell plasticity toward non-classic Th1 cells and an enhanced follicular regulatory T cells (Tfr) activity. The consequences of these regulatory properties are the reduction of systemic pathogenic antibody titers.

A myostatin-CCL20-CCR6 axis regulates Th17 cell recruitment to inflamed joints in experimental arthritis

The interactions of fibroblast-like synoviocyte (FLS)-derived pro-inflammatory cytokines/chemokines and immune cells support the recruitment and activation of inflammatory cells in RA. Here, we show for the first time that the classical myokine myostatin (GDF-8) is involved in the recruitment of Th17 cells to inflammatory sites thereby regulating joint inflammation in a mouse model of TNFalpha-mediated chronic arthritis. Mechanistically, myostatin-deficiency leads to decreased levels of the chemokine CCL20 which is associated with less infiltration of Th17 cells into the inflamed joints. In vitro, myostatin alone or in combination with IL-17A enhances the secretion of CCL20 by FLS whereas myostatin-deficiency reduces CCL20 secretion, associated with an altered transmigration of Th17 cells. Thus, the communication between activated FLS and Th17 cells through myostatin and IL-17A may likely contribute to a vicious cycle of inflammation, accounting for the persistence of joint inflammation in chronic arthritis. Blockade of the CCL20–CCR6 axis by inhibition of myostatin may, therefore, be a promising treatment option for chronic inflammatory diseases such as arthritis.

Suppression of Rheumatoid Arthritis by Enhanced Lymph Node Trafficking of Engineered Interleukin-10 in Murine Models

OBJECTIVE

Rheumatoid arthritis (RA) is a major autoimmune disease that causes synovitis and joint damage. Although clinical trials have been performed using interleukin-10 (IL-10), an antiinflammatory cytokine, as a potential treatment of RA, the therapeutic effects of IL-10 have been limited, potentially due to insufficient residence in lymphoid organs, where antigen recognition primarily occurs. This study was undertaken to engineer an IL-10-serum albumin (SA) fusion protein and evaluate its effects in 2 murine models of RA.

METHODS

SA-fused IL-10 (SA-IL-10) was recombinantly expressed. Mice with collagen antibody-induced arthritis (n = 4-7 per group) or collagen-induced arthritis (n = 9-15 per group) were injected intravenously with wild-type IL-10 or SA-IL-10, and the retention of SA-IL-10 in the lymph nodes (LNs), immune cell composition in the paws, and therapeutic effect of SA-IL-10 on mice with arthritis were assessed.

RESULTS

SA fusion to IL-10 led to enhanced accumulation in the mouse LNs compared with unmodified IL-10. Intravenous SA-IL-10 treatment restored immune cell composition in the paws to a normal status, elevated the frequency of suppressive alternatively activated macrophages, reduced IL-17A levels in the paw-draining LN, and protected joint morphology. Intravenous SA-IL-10 treatment showed similar efficacy as treatment with an anti-tumor necrosis factor antibody. SA-IL-10 was equally effective when administered intravenously, locally, or subcutaneously, which is a benefit for clinical translation of this molecule.

CONCLUSION

SA fusion to IL-10 is a simple but effective engineering strategy for RA therapy and has potential for clinical translation.

Human umbilical cord mesenchymal stem cell-derived small extracellular vesicles ameliorate collagen-induced arthritis via immunomodulatory T lymphocytes

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease for which there are currently no effective therapies. Although mesenchymal stem cells (MSCs) can prevent arthritis through immunomodulatory mechanisms, there are several associated risks. Alternatively, MSC-derived small extracellular vesicles (sEVs) can mimic the effects of MSCs, while reducing the risk of adverse events. However, few studies have examined sEVs in the context of RA. Here, we evaluate the immunomodulatory effects of human umbilical cord MSC (hUCMSC)-derived sEVs on T lymphocytes in a collagen-induced arthritis (CIA) rat model to elucidate the possible mechanism of sEVs in RA treatment. We then compare these mechanisms to those of MSCs and methotrexate (MTX).

METHODS

The arthritis index and synovial pathology were assessed. T lymphocyte proliferation and apoptosis, Th17 and Treg proportions, and interleukin (IL)-17, IL-10, and transforming growth factor (TGF)-β expression were detected using flow cytometry. Retinoic acid receptor-related orphan receptor gamma t (RORγt) and forkhead box P3 (FOXP3), which are master transcriptional regulators of Th17 and Treg differentiation, were also assessed using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

sEV treatment ameliorated arthritis and inhibited synovial hyperplasia in a dose-dependent manner. These effects were mediated by inhibiting T lymphocyte proliferation and promoting their apoptosis, while decreasing Th17 cell proportion and increasing that of Treg cells in the spleen, resulting in decreased serum IL-17, and enhanced IL-10 and TGF-β expression. Transcriptionally, sEVs decreased RORγt and increased FOXP3 expression in the spleen, and decreased RORγt and FOXP3 expression in the joints. In some aspects sEVs were more effective than MSCs and MTX in treating CIA.

CONCLUSIONS

hUCMSC-derived sEVs ameliorate CIA via immunomodulatory T lymphocytes, and might serve as a new therapy for RA.

Effect of combined application of iguratimod in the treatment of active rheumatoid arthritis on bone metabolism, Th17 cells and Treg cells

OBJECTIVE

This study was designed to analyse the effect of combined application of iguratimod with methotrexate in the treatment of active rheumatoid arthritis (RA).

METHODS

A total of 115 patients with active RA admitted to our hospital were enrolled and divided into group A (n=58) and group B (n=57) according to the method of random number table. Patients in group B were treated with methotrexate alone, while patients in group A were treated with methotrexate combined with iguratimod. The curative efficacy was compared between the two groups.

RESULTS

At 6 months after treatment, the levels of CTX-1 and RANKL in group A were higher than those in group B, and the levels of OPG, IL-17 and TGF-α in group A were lower than those in group B (P<0.05). The level of Th17 cells in group A was higher than that in group B, and the level of Treg cells in group A was lower than that in group B at 6 months after treatment (P<0.05). Tender joints count, swollen joints count and DAS28 score in group A were less than those in group B at 6 months after treatment (P<0.05). The duration of morning stiffness of the joints and the score of joint pain degree in group A were less than those in group B at 1, 2, 3, 4, 5, and 6 months after treatment (P<0.05).

CONCLUSION

The combined application of methotrexate and iguratimod in the treatment of active RA can effectively improve bone metabolism, regulate the levels of Th17 and Treg cells, play a prominent role in anti-inflammatory effect, and relieve symptoms, and thus achieve a more satisfactory curative effect.

Extracellular Vesicles and Immune System in Ageing and Immune Diseases

Immune system is essential for host homeostasis. Immune cells communicate with each other by binding to receptors or by releasing vesicles including chemokines and cytokines. Under healthy circumstances, immune cell-derived factors are critical for cellular growth, division and function, whereas under conditions such as ageing and inflammatory states, they can aggravate pathologies and cause disease. Cell-derived membranous extracellular vesicles mediate cell-to-cell communication and are implicated in various physiological and pathological processes involving ageing and age-related diseases. Extracellular vesicles are responsible for spreading detrimental factors to the surroundings and the propagation phase of inflammatory diseases. The regulation of extracellular vesicles is a putative target for treatment of inflammatory diseases. Moreover, their features are ideal for developing biomarkers and drug delivery systems modulated by bioengineering in inflammatory diseases. The present review summarizes the current understanding of extracellular vesicles in ageing and inflammatory diseases.

Infrared radiation from cage bedding moderates rat inflammatory and autoimmune responses in collagen-induced arthritis

The development of collagen type II (CII)-induced arthritis (CIA), a model of rheumatoid arthritis, in rats housed in cages with bedding composed of Celliant fibres containing ceramic particles, which absorb body heat and re-emit the energy back to the body in the form of infrared radiation (+IRF rats), and those housed in cages with standard wooden shaving bedding (-IRF control rats) was examined. The appearance of the first signs of CIA was postponed, while the disease was milder (judging by the arthritic score, paw volume, and burrowing behaviour) in +IRF compared with -IRF rats. This correlated with a lower magnitude of serum anti-CII IgG antibody levels in +IRF rats, and lower production level of IL-17, the Th17 signature cytokine, in cultures of their paws. This could be partly ascribed to impaired migration of antigen-loaded CD11b + dendritic cells and their positioning within lymph nodes in +IRF rats reflecting diminished lymph node expression of CCL19 /CCL21. Additionally, as confirmed in rats with carrageenan-induced paw inflammation (CIPI), the infrared radiation from Celliant fibres, independently from immunomodulatory effects, exerted anti-inflammatory effects (judging by a shift in pro-inflammatory mediator to anti-inflammatory/immunoregulatory mediator ratio towards the latter in paw cultures) and ameliorated burrowing behaviour in CIA rats.

Th17 Cells in Inflammatory Bowel Disease: Cytokines, Plasticity, and Therapies

Autoimmune diseases (such as rheumatoid arthritis, asthma, autoimmune bowel disease) are a complex disease. Improper activation of the immune system or imbalance of immune cells can cause the immune system to transform into a proinflammatory state, leading to autoimmune pathological damage. Recent studies have shown that autoimmune diseases are closely related to CD4+ T helper cells (Th). The original CD4 T cells will differentiate into different T helper (Th) subgroups after activation. According to their cytokines, the types of Th cells are different to produce lineage-specific cytokines, which play a role in autoimmune homeostasis. When Th differentiation and its cytokines are not regulated, it will induce autoimmune inflammation. Autoimmune bowel disease (IBD) is an autoimmune disease of unknown cause. Current research shows that its pathogenesis is closely related to Th17 cells. This article reviews the role and plasticity of the upstream and downstream cytokines and signaling pathways of Th17 cells in the occurrence and development of autoimmune bowel disease and summarizes the new progress of IBD immunotherapy.

Distinct Immunophenotypes of T Cells in Bronchoalveolar Lavage Fluid From Leukemia Patients With Immune Checkpoint Inhibitors-Related Pulmonary Complications

Patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) treated with immune checkpoint inhibitors (ICIs) are at risk of pneumonitis as well as pneumonia (combined henceforth as ICI-related pulmonary complications). Little is known about the cellular and molecular mechanisms underlying ICI-related pulmonary complications. We characterized lymphocytes from bronchoalveolar lavage (BAL) fluid and peripheral blood from seven AML/MDS patients with pulmonary symptoms after ICI-based therapy (ICI group) and four ICI-naïve AML/MDS patients with extracellular bacterial or fungal pneumonias (controls). BAL T cells in the ICI group were clonally expanded, and BAL IFNγ+ IL-17- CD8+ T and CXCR3+ CCR6+ Th17/Th1 cells were enriched in the ICI group. Our data suggest that these cells may play a critical role in the pathophysiology of ICI-related pulmonary complications. Understanding of these cell populations may also provide predictive and diagnostic biomarkers of ICI-related pulmonary complications, eventually enabling differentiation of pneumonitis from pneumonia in AML/MDS patients receiving ICI-based therapies.

Immunological Aspects of Age-Related Macular Degeneration

Increasing evidence over the past two decades points to a pivotal role for immune mechanisms in age-related macular degeneration (AMD) pathobiology. In this chapter, we will explore immunological aspects of AMD, with a specific focus on how immune mechanisms modulate clinical phenotypes of disease and severity and how components of the immune system may serve as triggers for disease progression in both dry and neovascular AMD. We will briefly review the biology of the immune system, defining the role of immune mechanisms in chronic degenerative disease and differentiating from immune responses to acute injury or infection. We will explore current understanding of the roles of innate immunity (especially macrophages), antigen-specific immunity (T cells, B cells, and autoimmunity), immune amplifications systems, especially complement activity and the NLRP3 inflammasome, in the pathogenesis of both dry and neovascular AMD, reviewing data from pathology, experimental animal models, and clinical studies of AMD patients. We will also assess how interactions between the immune system and infectious pathogens could potentially modulate AMD pathobiology via alterations in in immune effector mechanisms. We will conclude by reviewing the paradigm of "response to injury," which provides a means to integrate various immunologic mechanisms along with nonimmune mechanisms of tissue injury and repair as a model to understand the pathobiology of AMD.

Mango ginger (curcuma amada) inhibits collagen-induced arthritis by modulating inflammatory cytokine levels in rats

Background/aim

Mango ginger (MG: curcuma amada) has antioxidant and antiinflammatory activities. The aim was to evaluate the antiarthritic potential efficacy of MG on collagen-induced arthritis.

Materials and methods

Twenty-one female Wistar-albino rats were divided into three groups. Arthritis was induced by intradermal injections of type II collagen and Freund’s adjuvant. MG extract was orally administered starting from the first collagen injection. TNF-α, IL-6, IL-17, obestatin, sclerostin, and DKK-1 serum levels were determined, and perisynovial inflammation and cartilage-bone destruction in the paws were histologically evaluated. Moreover, joint tissue TNF-α, IL-17, NF-κB, and COX-2 levels were analyzed.

Results

TNF-α, IL-17, IL-6, and DKK-1 serum levels were increased, and obestatin and sclerostin serum levels were decreased in the arthritis group compared to the control group. However, MG supplements decreased TNF-α, IL-17, IL-6, and DKK-1 serum levels and increased obestatin and sclerostin serum levels. Similarly, while collagen injection increased tissue TNF-α, IL-17, NF-κB, and COX-2 levels, MG decreased TNF-α, IL-17, and NF-κB levels. Moreover, MG ameliorated perisynovial inflammation and cartilage-bone destruction in the paws.

Conclusion

MG ameliorates arthritis via actions on inflammatory ways and wingless (Wnt) signaling pathway. These results suggest that MG may have a considerable potential efficacy for the treatment of rheumatoid arthritis.

Aberrant expression of USF2 in refractory rheumatoid arthritis and its regulation of proinflammatory cytokines in Th17 cells

IL-17-producing Th17 cells are implicated in the pathogenesis of rheumatoid arthritis (RA) and TNF-α, a proinflammatory cytokine in the rheumatoid joint, facilitates Th17 differentiation. Anti-TNF therapy ameliorates disease in many patients with rheumatoid arthritis (RA). However, a significant proportion of patients do not respond to this therapy. The impact of anti-TNF therapy on Th17 responses in RA is not well understood. We conducted high-throughput gene expression analysis of Th17-enriched CCR6+CXCR3-CD45RA- CD4+ T (CCR6+ T) cells isolated from anti-TNF-treated RA patients classified as responders or nonresponders to therapy. CCR6+ T cells from responders and nonresponders had distinct gene expression profiles. Proinflammatory signaling was elevated in the CCR6+ T cells of nonresponders, and pathogenic Th17 signature genes were up-regulated in these cells. Gene set enrichment analysis on these signature genes identified transcription factor USF2 as their upstream regulator, which was also increased in nonresponders. Importantly, short hairpin RNA targeting USF2 in pathogenic Th17 cells led to reduced expression of proinflammatory cytokines IL-17A, IFN-γ, IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as well as transcription factor T-bet. Together, our results revealed inadequate suppression of Th17 responses by anti-TNF in nonresponders, and direct targeting of the USF2-signaling pathway may be a potential therapeutic approach in the anti-TNF refractory RA.

Trichinella spiralis: inflammation modulator

The hygiene hypothesis posits that the decreased incidence of parasitic infection in developed countries may underlie an increased prevalence of allergic and autoimmune diseases in these countries. As unique inflammation modulator of intracellular parasitism, Trichinella spiralis, or its excretory-secretory (ES) product, shows improved responses to allergies, autoimmune diseases, inflammatory bowel disease, type 1 diabetes, rheumatic arthritis and autoimmune encephalomyelitis by exerting immunomodulatory effects on both innate and adaptive immune cells in animal models. Research has shown that T. spiralis differs from other helminths in manipulation of the host immune response not only by well-known characteristics of its life cycle, but also by its inflammation modulation pathway. How the parasite achieves inflammation modulation has not been fully elucidated yet. This review will generalize the mechanism and focuses on ES immunomodulatory molecules of T. spiralis that may be important for developing new therapeutics for inflammatory disorders.

Methrotexate Treatment Inmunomodulates Abnormal Cytokine Expression by T CD4 Lymphocytes Present in DMARD-Naïve Rheumatoid Arthritis Patients

CD4+T-lymphocytes are relevant in the pathogenesis of rheumatoid arthritis (RA), however, their potential involvement in early RA remains elusive. Methotrexate (MTX) is a commonly used disease-modifying antirheumatic drug (DMARD), but its mechanism has not been fully established. In 47 new-onset DMARD-naïve RA patients, we investigated the pattern of IFNγ, IL-4 and IL-17A expression by naïve (TN), central (TCM), effector memory (TEM) and effector (TE) CD4+ subsets; their STAT-1, STAT-6 and STAT-3 transcription factors phosphorylation, and the circulating levels of IFNγ, IL-4 and IL-17. We also studied the RA patients after 3 and 6 months of MTX treatment and according their clinical response. CD4+T-lymphocyte subsets and cytokine expression were measured using flow cytometry. New-onset DMARD-naïve RA patients showed a significant expansion of IL-17A+, IFNγ+ and IL-17A+IFNγ+ CD4+T-lymphocyte subsets and increased intracellular STAT-1 and STAT-3 phosphorylation. Under basal conditions, nonresponder patients showed increased numbers of circulating IL-17A producing TN and TMC CD4+T-lymphocytes and IFNγ producing TN, TCM, TEM CD4+T-lymphocytes with respect to responders. After 6 months, the numbers of CD4+IL-17A+TN remained significantly increased in nonresponders. In conclusion, CD4+T-lymphocytes in new-onset DMARD-naïve RA patients show IL-17A and IFNγ abnormalities in TN, indicating their relevant role in early disease pathogenesis. Different patterns of CD4+ modulation are identified in MTX responders and nonresponders.

Molecular and Cellular Mechanisms of Arthritis in Children and Adults: New Perspectives on Applied Photobiomodulation

Juvenile idiopathic arthritis and adult rheumatoid arthritis are two major groups with chronic joint pain and inflammation, extra-articular manifestations, and high risk of comorbidities, which can cause physical and ocular disability, as well as create great socio-economic pressure worldwide. The pathogenesis of arthritis manifested in childhood and adulthood is multifactorial, unclear, and overly complex, in which immunity plays an important role. Although there are more and more biological agents with different mechanisms of action for the treatment of arthritis, the results are not as expected, because there are partial responses or non-responsive patients to these compounds, high therapeutic costs, side effects, and so on; therefore, we must turn our attention to other therapeutic modalities. Updating knowledge on molecular and cellular mechanisms in the comparative pathogenesis of chronic arthritis in both children and adults is necessary in the early and correct approach to treatment. Photobiomodulation (PBM) represents a good option, offering cost-effective advantages over drug therapy, with a quicker, more positive response to treatment and no side effects. The successful management of PBM in arthritis is based on the clinician's ability to evaluate correctly the inflammatory status of the patient, to seek the optimal solution, to choose the best technology with the best physical parameters, and to select the mode of action to target very precisely the immune system and the molecular signaling pathways at the molecular level with the exact amount of quantum light energy in order to obtain the desired immune modulation and the remission of the disease. Light is a very powerful tool in medicine because it can simultaneously target many cascades of immune system activation in comparison with drugs, so PBM can perform very delicate tasks inside our cells to modulate cellular dysfunctions, helping to initiate self-organization phenomena and finally, healing the disease. Interdisciplinary teams should work diligently to meet these needs by also using single-cell imaging devices for multispectral laser photobiomodulation on immune cells.

Low levels of pro-resolving lipid mediators lipoxin-A4, resolvin-D1 and resolvin-E1 in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a disease in which joint inflammation is at the forefront but the whole body is affected, and prevention of inflammation is the main treatment approach. Lipoxins (LXs) and resolvins (Rvs) are critical molecules in the resolution of inflammation. In this study, we aimed to investigate the role of LXs and Rvs in the RA pathogenesis. To this end, we measured the LXA 4, RvD 1, RvE 1 levels, and inflammatory cytokines and chemokines IL-6, IL-8, IL-10, IL-17a, IL-22 and MCP-1 in patients with RA and healthy individuals. We found that the LXA4, RvD1, RvE1 levels of the active RA cases were significantly lower than in remission RA and healthy individuals, but the levels of inflammatory cytokines and chemokines were significantly higher. The decreases in LXs and Rvs were independent of disease activity, suggesting that there might be an impairment of LX and Rvs synthesis or catabolism in patients with RA.

Low-dose Interleukin-2: Biology and therapeutic prospects in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic aggressive arthritis that is characterized with systemic inflammation response, the production of abnormal antibodies, and persistent synovitis. One of the key mechanisms underlying the pathogenesis of RA is the imbalance of CD4 + T lymphocyte subsets, from T helper (Th) 17 cells and regulatory T (Treg) cells to T follicular helper (Tfh) cells and T follicular regulatory (Tfr) cells, which can mediate autoimmune inflammatory response to promote the overproduction of cytokines and abnormal antibodies. Although the treatment of RA has greatly changed due to the discovery of biological agents such as anti-TNF, the remission of it is still not satisfactory, thus, it is urgently required new treatment to realize the sustained remission of RA via restoring the immune tolerance. Interleukin-2 (IL-2) has been discovered to be a pleiotropic cytokine to promote inflammatory response and maintain immune tolerance. Low-dose IL-2 therapy is a driver of the imbalance between autoimmunity and immune tolerance towards immune tolerance, which has been tried to treat various autoimmune diseases. Recent researches show that low-dose IL-2 is a promising treatment for RA. In this review, we summarize the advances understandings in the biology of IL-2 and highlight the impact of the IL-2 pathway on the balance of Th17/Treg and Tfh/Tfr aiming to investigate the role of IL-2-mediated immune tolerance in RA and discuss the application and the therapeutic prospect of low-dose IL-2 in the treatment of RA.

Cellular and Molecular Pathways of COVID-19 and Potential Points of Therapeutic Intervention

With the objective of linking early findings relating to the novel SARS-CoV-2 coronavirus with potentially informative findings from prior research literature and to promote investigation toward therapeutic response, a coherent cellular and molecular pathway is proposed for COVID-19. The pathway is consistent with a broad range of observed clinical features and biological markers and captures key mediators of pathophysiology. In this proposed pathway, membrane fusion and cytoplasmic entry of SARS-CoV-2 virus via ACE2 and TMPRSS2-expressing respiratory epithelial cells, including pulmonary type-II pneumocytes, provoke an initial immune response featuring inflammatory cytokine production coupled with a weak interferon response, particularly in IFN-λ-dependent epithelial defense. Differentiation of non-classic pathogenic T-cells and pro-inflammatory intermediate monocytes contributes to a skewed inflammatory profile, mediated by membrane-bound immune receptor subtypes (e.g., FcγRIIA) and downstream signaling pathways (e.g., NF-κB p65 and p38 MAPK), followed by chemotactic infiltration of monocyte-derived macrophages and neutrophils into lung tissue. Endothelial barrier degradation and capillary leakage contribute to alveolar cell damage. Inflammatory cytokine release, delayed neutrophil apoptosis, and NETosis contribute to pulmonary thrombosis and cytokine storm. These mechanisms are concordant with observed clinical markers in COVID-19, including high expression of inflammatory cytokines on the TNF-α/IL-6 axis, elevated neutrophil-to-lymphocyte ratio (NLR), diffuse alveolar damage via cell apoptosis in respiratory epithelia and vascular endothelia, elevated lactate dehydrogenase (LDH) and CRP, high production of neutrophil extracellular traps (NETs), depressed platelet count, and thrombosis. Although certain elements are likely to be revised as new findings emerge, the proposed pathway suggests multiple points of investigation for potential therapeutic interventions. Initial candidate interventions include prophylaxis to augment epithelial defense (e.g., AT1 receptor blockade, type III and type I interferons, melatonin, calcitriol, camostat, and lopinavir) and to reduce viral load (e.g., remdesivir, ivermectin, emetine, Abelson kinase inhibitors, dopamine D2 antagonists, and selective estrogen receptor modulators). Additional interventions focus on tempering inflammatory signaling and injury (e.g., dexamethasone, doxycycline, Ang1-7, estradiol, alpha blockers, and DHA/EPA, pasireotide), as well as inhibitors targeted toward molecular mediators of the maladaptive COVID-19 immune response (e.g., IL-6, TNF-α, IL-17, JAK, and CDK9).

T-bet Expression in Peripheral Th17.0 Cells Is Associated With Pulmonary Function Changes in Sarcoidosis

Background: Interferon-gamma (IFN-γ) is a key mediator of sarcoidosis-related granulomatous inflammation. Previous findings of IFN-γ-producing Th17 cells in bronchoalveolar lavage fluid from sarcoidosis patients invokes the transition of Th17.0 cells to Th17.1 cells in the disease's pathogenesis. Since the T-bet transcription factor is crucial for this transition, the goal of this study was to determine if T-bet expression in Th17.0 cells reflects the extent of granulomatous inflammation in sarcoidosis patients as assessed by clinical outcomes.

Methods: Using a case-control study design, we identified two groups of sarcoidosis subjects (total N = 43) with pulmonary function tests (PFTs) that either (1) changed (increased or decreased) longitudinally or (2) were stable. We used flow cytometry to measure the transcription factors T-bet and RORγt in Th1, Th17.0, and Th17.1 cell subsets defined by CCR6, CCR4 and CXCR3 in blood samples. We compared the percentages of T-bet⁺ cells in RORγt⁺Th17.0 cells (defined as CCR6⁺CCR4⁺CXCR3⁻) based on subjects' PFT group. We also assessed the relationship between the direction of change in PFTs with the changes in %T-bet⁺ frequencies using mixed effects modeling.

Results: We found that T-bet expression in subjects' RORγt⁺Th17.0 cells varied based on clinical outcome. The T-bet⁺ percentage of RORγt⁺Th17.0 cells was higher in the cases (subject group with PFT changes) as compared to controls (stable group) (27 vs. 16%, p = 0.0040). In comparisons before and after subjects' PFT changes, the T-bet⁺ frequency of RORγt⁺Th17.0 cells increased or decreased in the opposite direction of the PFT change. The percentage of these T-bet⁺ cells was also higher in those with greater numbers of involved organs. Serum levels of interferon-γ-induced chemokines, CXCL9, CXCL10, and CXCL11, and whole blood gene expression of IFN-γ-related genes including GBP1, TAP1, and JAK2 were independently positively associated with the T-bet⁺ frequencies of RORγt⁺Th17.0 cells.

Conclusions: These data suggest that expression of T-bet in Th17.0 cells could reflect the extent of granulomatous inflammation in sarcoidosis patients because they represent a transition state leading to the Th17.1 cell phenotype. These findings indicate that Th17 plasticity may be part of the disease paradigm.

Immunometabolism: an overview and therapeutic prospects in autoimmune diseases

Metabolism is a critical immune regulator under physiologic and pathologic conditions. Culminating evidence has disentangled the contribution of distinct metabolic pathways, namely glucolysis, pentose phosphate, fatty acid oxidation, glutaminolysis, Krebs cycle and oxidative phosphorylation, in modulating innate and adaptive immune cells based on their activation/differentiation state. Metabolic aberrations and changes in the intracellular levels of specific metabolites are linked to the inflammatory phenotype of immune cells implicated in autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and diabetes. Notably, targeting metabolism such as the mTOR by rapamycin, hexokinase by 2-deoxy-D-glucose, AMP-activated protein kinase by metformin, may be used to ameliorate autoimmune inflammation. Accordingly, research in immunometabolism is expected to offer novel opportunities for monitoring and treating immune-mediated diseases.

Biodistribution and pharmacokinetic profiles of an altered peptide ligand derived from heat-shock proteins 60 in Lewis rats

Human heat-shock protein 60 (HSP60) is an autoantigen involved in the pathogenesis of rheumatoid arthritis (RA). Epitopes derived from HSP60 can trigger activation of regulatory T cells (Treg). CIGB-814 is an altered peptide ligand (APL) derived from HSP60. In preclinical models, this peptide had anti-inflammatory effects and increased Treg. The results from phase I clinical trial indicated that CIGB-814 was safe and activated mechanisms associated with induction of tolerance. Biodistribution profile for inducers of tolerance is crucial for triggering its effects. The primary goal of this study in Lewis rats was to identify (1) the target organs of CIGB-814 and (2) the pharmacokinetics (PK) profile. 125I-CIGB-814 administered subcutaneously at three dose levels was distributed in the thyroid gland, but also at considerable levels to the stomach and small and large intestines. In addition, concentration of CIGB-814 was increased in lymph nodes (LNs) at 24 h, compared with 4-h post-administration. Small intestine and LNs are excellent sites for induction of tolerance, due to the characteristics of dendritic cells in these tissues. Maximum concentration of CIGB-814 in blood of Lewis rats at 0.5 to 1 h agrees with PK profile determined for patients. Altogether, these results support therapeutic possibilities of CIGB-814 for RA.

A Clinical Approach for the Use of VIP Axis in Inflammatory and Autoimmune Diseases

The neuroendocrine and immune systems are coordinated to maintain the homeostasis of the organism, generating bidirectional communication through shared mediators and receptors. Vasoactive intestinal peptide (VIP) is the paradigm of an endogenous neuropeptide produced by neurons and endocrine and immune cells, involved in the control of both innate and adaptive immune responses. Exogenous administration of VIP exerts therapeutic effects in models of autoimmune/inflammatory diseases mediated by G-protein-coupled receptors (VPAC1 and VPAC2). Currently, there are no curative therapies for inflammatory and autoimmune diseases, and patients present complex diagnostic, therapeutic, and prognostic problems in daily clinical practice due to their heterogeneous nature. This review focuses on the biology of VIP and VIP receptor signaling, as well as its protective effects as an immunomodulatory factor. Recent progress in improving the stability, selectivity, and effectiveness of VIP/receptors analogues and new routes of administration are highlighted, as well as important advances in their use as biomarkers, contributing to their potential application in precision medicine. On the 50th anniversary of VIP's discovery, this review presents a spectrum of potential clinical benefits applied to inflammatory and autoimmune diseases.

Methotrexate Restores CD73 Expression on Th1.17 in Rheumatoid Arthritis and Psoriatic Arthritis Patients and May Contribute to Its Anti-Inflammatory Effect through Ado Production

Objectives: Th1.17 are highly polyfunctional, potentially harmful CD4⁺ effector T cells (Teff) through IFN-γ and IL-17A coproduction. Th1.17 take part in the pathophysiology of rheumatoid arthritis (RA) and psoriatic arthritis (PsA), in which their hyper activation results in part from defects in negative regulation mechanisms. We recently demonstrated that the ecto-nucleotidase CD73 delineates a Th1.17-enriched Teff population and acts as an endogenous regulatory mechanism. Because Methotrexate (MTX), used as first line treatment of RA and PsA, increases extracellular concentrations of AMP and immunosuppressive adenosine, we investigated the modulation of CD73 by MTX treatment on Teff in RA/PsA patients. Methods: In a prospective cohort of 26 RA and 15 PsA patients before or under MTX treatment, we evaluated CD73 expression on blood Teff subsets, their cytokine production and AMPase functions. Results: We showed a decreased CD73 expression on Th1.17 and Th1 in untreated patients compared to healthy donors that was partly restored under MTX. This decrease in untreated patients leads to a halved Ado production by Th1.17 cells. CD73⁺ Teff remained functional under MTX treatment, but their CD73 re-expression may contribute to control their activation. Conclusion: Our study unveils uncovered mode of action of MTX on Teff subsets modulation and in the adenosine-dependent termination of inflammation in RA and PsA.

Immunomodulatory effect of human umbilical cord mesenchymal stem cells on T lymphocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease which is lack of effective therapies. Abnormal activation, proliferation, and differentiation of T lymphocytes are closely related to RA. Mesenchymal stem cells (MSCs) can be used for RA treatment due to their immunoregulatory effects. However, the specific molecular mechanisms have not been fully elucidated and the therapeutic effect has been inconsistent. This study investigated the immunomodulatory effect of human umbilical cord MSCs (hUCMSCs) on T lymphocytes in collagen-induced arthritis (CIA) rats and RA patients to clarify the possible mechanism of hUCMSCs in RA treatment. The effects of hUCMSCs on arthritis index, radiological and synovial pathological changes, T lymphocyte proliferation and apoptosis, RORγt and Foxp3 expression, Th17 and Treg cell ratios, and IL-17 and TGF-β levels were assessed in CIA rats. Further, we verified the effect of hUCMSCs in RA patients, and compared the effect of hUCMSCs with that of hUCMSC derived extracellular vesicles (EVs). The results showed that hUCMSCs inhibited the proliferation and promoted apoptosis in T lymphocytes, downregulated RORγt mRNA and protein expression, decreased Th17 cell ratio, upregulated Foxp3 mRNA and protein expression, and increased Treg cell ratio in the spleen. Furthermore, they downregulated RORγt and Foxp3 expression in the joints, and inhibited IL-17 and promoted TGF-β expression in the serum, thereby improving arthritis, delaying radiological progression, and inhibiting synovial hyperplasia in CIA rats. In vitro the effects of hUCMSCs and EVs were consistent with those in vivo. Therefore, hUCMSCs may be expected to serve as a new therapy for RA.

The protease systems and their pathogenic role in juvenile idiopathic arthritis

Numerous proteases produced by synovial cells of arthritic joints, chondrocytes, macrophages and polymorphonuclear cells have been identified as responsible for the joint damage in rheumatoid arthritis. There are few scientific contributions aimed to identify similar mechanisms in the joints of patients with juvenile idiopathic arthritis. Recently, some mechanisms emerged, triggered by the TH17 and TH1/TH17 lymphocytes, which could shed new light on unexpected pathogenic pathways of joint damage in the JIA, mainly regarding the RANK-RANKL pathway. Other novelties are linked to the mechanisms of acidification of the synovial fluid, which create a microenvironment suitable for the extracellular activity of lysosomal enzymes. Some biological drugs currently used in the therapy of JIA can interfere with these mechanisms.