Innate Lymphocytes in Inflammatory Arthritis

Unraveling new therapeutic targets in ankylosing spondylitis: Multi-omics Mendelian randomization on immune cells, metabolites, and inflammation proteins

This study aims to identify novel immunological, metabolic, and inflammatory determinants of ankylosing spondylitis (AS) using Mendelian randomization (MR), offering new insights into its pathogenesis and potential therapeutic interventions. Employing a bidirectional, secondary validation two-sample MR, this study investigated causal associations among 1400 serum metabolites, 731 immune cell traits, and 91 circulating inflammatory proteins with AS. Instrumental variables were identified using PLINK for minimal linkage disequilibrium, applying strict significance thresholds. Various MR methodologies, including inverse variance weighted, weighted median, and MR Egger, were applied to validate causal links. Sensitivity analyses, incorporating heterogeneity and pleiotropy tests, were performed to evaluate the robustness of the results. The false discovery rate correction was applied to adjust for multiple comparisons, while the MR Steiger directionality test and bidirectional MR analysis validated the causation direction. Secondary validation with data from diverse sources was undertaken to confirm the reliability of the findings. After false discovery rate correction, associations were identified between AS etiology and 9 immune cell traits, 2 serum metabolites, and 2 inflammatory proteins. Notably, the presence of CX3CR1 on monocytes and the absolute count of CD62L- CD86+ myeloid dendritic cells (DCs) were associated with an increased risk of AS. In contrast, expression of HLA DR on DCs, including myeloid and plasmacytoid DCs, and on CD14- CD16- monocytes, along with CD64 expression across various monocyte subsets (monocytes, CD14+ CD16+, and CD14+ CD16-), correlated with a decreased risk of AS development. Serum metabolites, specifically levels of hexadecanedioate and Bilirubin (E, Z or Z, E), were also linked to a reduced risk of AS. Regarding inflammatory factors, interleukin-6 levels were inversely associated with AS morbidity, whereas TNF-beta levels were positively correlated with higher AS morbidity. Neither bidirectional MR nor MR Steiger tests provided evidence supporting reverse causation. This study sheds light on the complex interactions between immune cells traits, metabolites, and inflammatory proteins in AS, offering new insights into its pathophysiology. The findings underscore the importance of the immune-metabolic-inflammation network in AS, suggesting novel biomarkers for diagnosis and targets for therapy.

In silico and in vitro studies for the identification of small molecular inhibitors from Euphorbia hirta Linn for rheumatoid arthritis: targeting TNF-α-mediated inflammation

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that is now potentially lethal and has a significant detrimental influence on people's daily lives by affecting bone joints. Inflammation plays a vital role in this type of autoimmune disorder. In rheumatoid arthritis, long-term production of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) stimulates the immune system against cells in bone joints and helps to develop the pathogenesis of rheumatoid arthritis. So, while treating rheumatoid arthritis, we need to block these kinds of mechanisms. We employed soxhlet extraction, thin-layer chromatography (TLC), and gas chromatography-mass spectroscopy (GC-MS) to analyze the phytocompound information in E. hirta leaves. Furthermore, our research included in vitro investigations using Western blotting and mRNA expression analysis (TNF-α, IL-1β, IL-6) to affirm the anti-inflammatory effectiveness of our extract. For identifying the lead-like molecules, virtual screening and molecular dynamics simulations were used. TLC results confirmed the presence of phytocompounds in E. hirta crude through spots. The structure elucidation of the phytocompounds was confirmed by the GC-MS chromatogram. The in vitro outcomes collectively underscore the inhibitory influence of E. hirta on cell proliferation and its capacity to attenuate the expression of TNF- α within THP-1 cells. The results of in silico methodologies confirmed six lead-like molecules. We could conclude that phytocompounds from ethanol leaf crude have effective lead-like molecules against the TNF-α.

Prevalence of complementary therapy use in patients with inflammatory arthritis: a cross-sectional study in China

This study aimed to evaluate the utilization of complementary and alternative medicine (CAM) among Chinese patients with inflammatory arthritis (IA), the types of CAM used, and the factors associated with its use. This cross-sectional study was conducted at the Department of Rheumatology and Immunology at the First Affiliated Hospital of Anhui Medical University. Data were collected from 503 IA patients using self-administered questionnaires and electronic medical records. Demographic, clinical, and disease activity data and pain, fatigue, emotion, and sleep quality assessments were analyzed. The study found that 50.3% of patients with IA used CAM, with herbal medicines and products being the most common therapies utilized by 74.3% of CAM users. CAM users reported significantly higher levels of fatigue, negative emotion states, and poorer sleep quality compared to non-users. Multivariate logistic regression analysis identified age, employment status, disease duration, IA family history, and disease activity as significant predictors of CAM use. This study revealed a high prevalence of CAM use among patients with IA in China. Healthcare professionals should enhance their understanding of CAM to inform and guide patients better and ensure the safe and effective integration of CAM therapies with conventional treatments.

Causal Association Between Chronic Inflammatory Arthropathies and Sarcopenia and the Mediation Role of Inflammatory Factors

BACKGROUND

Although chronic inflammatory arthropathies (CIA) are associated with sarcopenia, sarcopenia plays a role in their pathogenesis remains unknown. This study investigated the causal relationship between sarcopenia and CIA and to identify potential mediating factors.

METHODS

We examined data from 458 910 participants in the UK Biobank to analyze the association between sarcopenia-related traits and CIA. Associations between hand-grip strength, muscle mass, walking pace, and CIA were analyzed using Cox regression models. Then, we performed a mediation analysis to explore the underlying mechanisms.

RESULTS

Individuals with low hand-grip strength exhibited a 1.88-fold (95% CI 1.73-2.05), 2.22-fold (95% CI 2.02-2.45), and 1.36-fold (95% CI 1.32-1.41) increased risk of rheumatoid arthritis (RA), spondyloarthritis (SpA), and osteoarthritis (OA), respectively. The HRs for sarcopenia were 1.64 (95% CI 1.15-2.32) for RA, 1.83 (95% CI 1.21-2.77) for SpA, and 1.26 (95% CI 1.09-1.45) for OA. Additionally, individuals with a slow walking pace exhibited a 1.83-fold (95% CI 1.66-2.02), 3.58-fold (95% CI 3.25-3.95), and 1.82-fold (95% CI 1.77-1.88) increased risk of RA, SpA, and OA, respectively. Furthermore, we identified inflammatory markers as possible mediators of the causal effects of low hand-grip strength on the development of CIA.

CONCLUSIONS

Our findings suggest that sarcopenia is independently associated with an increased risk of CIA, which is partially mediated by inflammation factors.

Immunological biomarkers in patients with radiographic axial spondyloarthritis, an exploratory longitudinal Swedish study

OBJECTIVES

There is a need for more specific biomarkers to diagnose and predict disease course in patients with axial spondyloarthritis (axSpA). This study aimed to study immunological plasma biomarkers at different time-points in radiographic (r)-axSpA patients overall and stratified by sex and compare these biomarker patterns in r-axSpA patients concerning disease phenotypes and disease activity.

METHODS

Plasma samples were analysed from r-axSpA patients at and prior (Pre-Backbone) inclusion in the Backbone study. Interferon gamma, interleukin-10, -17A, -17F, -22, -23, -6, MCP-1, TNF-α, VEGF-A, MIF, IgA anti-CD74, zonulin, ESR, hsCRP, white blood cell count, and blood lipids were measured.

RESULTS

Biomarker pattern discriminated significantly between r-axSpA patients in Backbone and Pre-Backbone compared with controls. When stratifying by sex, it was possible to discriminate between male and female r-axSpA patients in Backbone vs controls and between male r-axSpA patients in pre-Backbone and controls. In Backbone, markers with high discriminative capacity were MIF, IgA anti-CD74, and MCP-1. In Pre-Backbone, IL-6, TNF-α, MIF, triglycerides, cholesterol, IL-10, and zonulin displayed high discriminative capacity.

CONCLUSION

Based on their temporal pattern and mutual relationship, we suggest studying MIF, IgA anti-CD74, and MCP-1 in depth, at more time points, to further elucidate disease-driving mechanisms in this complex disease.

The real experience of reporting electronic patient-reported outcomes in patients with inflammatory arthritis and factors influencing participation: a scoping review

Inflammatory arthritis can result in pain, stiffness, fatigue, and reduce quality of life. Frequent monitoring of disease activity is necessary for patients with inflammatory arthritis, and electronic patient-reported outcomes (ePROs) play a crucial role in this process. This study aimed to investigate the real experience of reporting ePROs in patients with inflammatory arthritis, as well as to identify factors influencing participation. The ultimate goal was to inform targeted strategies and develop interventions to enhance the utilization of ePROs in clinical settings. A scoping review was performed using PubMed, Web of science, Embase, and the Cochrane library from 2000 to the present and the literature search focused on the experience of reporting ePROs in inflammatory arthritis and the factors that influence participation. Screening articles based on inclusion and exclusion criteria. A total of 1478 studies were identified, out of which 26 were included in the review. The top experience of applications/platforms in patients was that they were easy to use and that the applications were clear, logical and intuitive. A summary of 18 potential influencing factors were identified and there was inconsistent evidence for five of these factors. The participation of reporting ePROs is influenced by various factors, and the experience is a crucial aspect in patients with inflammatory arthritis. Analyzing patients' experience and influencing factors provides a theoretical basis for future interventions to facilitate the clinical application of ePRO. However, further research is needed to fully understand the association between influencing factors and intervention outcomes.

Risk factors for type 2 diabetes mellitus in Chinese rheumatoid arthritis patients from 2018 to 2022: a real-world, single-center, retrospective study

Introduction

In patients with rheumatoid arthritis (RA), the increased risk of concomitant type 2 diabetes mellitus (T2D) is an important contributor to increased mortality and decreased quality of life; however, the mechanisms and pathogenetic factors remain unknown.

Methods

In this study, we aimed to assess the risk factors for T2D in patients with RA. We recruited 206 healthy controls and 488 patients with RA, 160 of whom had comorbid T2D. General clinical information, disease characteristics, and circulating lymphocyte levels detected using modified flow cytometry were collected from all participants. Logistic regression models adjusted for confounders were fitted to estimate the risk factors of T2D in patients with RA.

Results

The incidence of RA in patients with T2D was 15.6%. Patients with RA and T2D had a longer disease duration, higher BMI, and a higher incidence of hypertension and a family history of diabetes than those with RA but no T2D. The absolute numbers of T helper 2 cell (Th2) and Regulatory T cells (Treg) decreased in patients with RA and T2D, which led to an increase in the ratios of Th1/Th2 and Th17/Treg cells. Multivariate logistic regression analysis showed that a family history of diabetes, a higher incidence of hypertension, higher neutrophil-lymphocyte ratio (NLR) levels, lower platelet-lymphocyte ratio (PLR) levels, and fewer circulating Th2 and Treg cells were associated with an increased risk of T2D in patients with RA.

Discussion

The levels of peripheral lymphocytes, especially Th2 and Treg cells, are closely related to the occurrence of T2D in patients with RA; however, the influence of body mass index (BMI), family history of diabetes, and systemic inflammation should not be ignored.

Diet affects inflammatory arthritis: a Mendelian randomization study of 30 dietary patterns causally associated with inflammatory arthritis

Background

The causal associations between dietary intake and the risk and severity of Inflammatory Arthritis (IA) are currently unknown.

Objective

In this study, we aimed to investigate the causal relationship between nine dietary categories (30 types of diet) and IA using Mendelian randomization (MR).

Methods

We analyzed data from 30 diets and IA in a genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) that could influence the results of MR analyses were screened out through the Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test. SNPs were analyzed through two-sample bidirectional MR using inverse variance weighting, MR-Egger regression, and weighted median method. The multiplicity and heterogeneity of SNPs were assessed using MR-Egger intercept term tests and Cochran's Q tests. FDR correction was used to correct the p-values.

Results

IVW results showed that Beef intake [Odds ratio (OR) = 2.862; 95% confidence interval (CI), 1.360-6.021, p = 0.006, p_fdr < 0.05] was positively associated with rheumatoid arthritis(RA); Dried fruit intake (OR = 0.522; 95% CI, 0.349-0.781, p = 0.002, p_fdr < 0.05), and Iron intake (OR = 0.864; 95%CI, 0.777-0.960, p = 0.007, p_fdr < 0.05) were negatively associated with RA, all of which were evidence of significance. Fresh fruit intake (OR = 2.528. 95% CI, 1.063-6.011, p = 0.036, p_fdr > 0.05) was positively associated with psoriatic arthritis (PsA); Cheese intake (OR = 0.579; 95% CI, 0.367-0.914, p = 0.019, p_fdr > 0.05) was negatively associated with PsA; both were suggestive evidence. Processed meat intake (OR = 0.238; 95% CI, 0.100-0.565, p = 0.001, p_fdr < 0.05) was negatively associated with reactive arthritis (ReA), a protective factor, and significant evidence. All exposure data passed the heterogeneity check (Cochrane's Q test p > 0.05) and no directional pleiotropy was detected. Leave-one-out analyses demonstrated the robustness of the causal relationship in the positive results.

Conclusion

Our study presents genetic evidence supporting a causal relationship between diet and an increased risk of IA. It also identifies a causal relationship between various dietary modalities and different types of IA. These findings have significant implications for the prevention and management of IA through dietary modifications.

Single-cell transcriptome revealed dysregulated RNA-binding protein expression patterns and functions in human ankylosing spondylitis

Objective

To explore the expression characteristics and regulatory patterns of RBPs in different immune cell types of AS, and to clarify the potential key role of RBPs in the occurrence and development of AS disease.

Methods

PBMC sample data from scRNA-seq (HC*29, AS*10) and bulk RNA-seq (NC*3, AS*5) were selected for correlation analysis.

Results

(1) Compared with the HC group, the numbers of B, DC (dendritic cells), CD14+ Mono and CD8+ T cells were increased in AS group, while the numbers of platelet (platelets), CD8+ NKT, CD16+ Mono (non-classical monocytes), Native CD4+ T and NK were decreased. (2) Through the analysis of RBP genes in B cells, some RBPs were found to play an important role in B cell differentiation and function, such as DDX3X, SFPQ, SRRM1, UPF2. (3) It may be related to B-cell receptor, IgA immunity, NOD-like receptor and other signaling pathways; Through the analysis of RBP genes in CD8+ T cells, some RBPs that play an important role in the immune regulation of CD8+ T were found, such as EIF2S3, EIF4B, HSPA5, MSL3, PABPC1 and SRSF7; It may be related to T cell receptor, TNF, IL17 and other signaling pathways. (4) Based on bulk RNA-seq, it was found that compared with HC and AS patients, differentially expressed variable splicing genes (RASGs) may play an important role in the occurrence and development of AS by participating in transcriptional regulation, protein phosphorylation and ubiquitination, DNA replication, angiogenesis, intracellular signal transduction and other related pathways.

Conclusion

RBPs has specific expression characteristics in different immune cell types of AS patients, and has important regulatory functions. Its abnormal expression and regulation may be closely related to the occurrence and development of AS.

Presence of periodontal disease and the incidence of inflammatory arthritides in the general population: data from the UK Biobank

OBJECTIVES

To investigate the association between periodontal disease and the development of inflammatory arthritides in the general population.

METHODS

In total, 489 125 participants from the UK Biobank without a previous history of RA, AS and PsA were enrolled. The primary outcome was the incidence of inflammatory arthritides, which was a composite of RA, AS and PsA according to the presence of periodontal disease based on self-reported oral health indicators. Multivariate Cox proportional hazard regression analyses using four different models were performed to assess the association between periodontal disease and inflammatory arthritides development.

RESULTS

In all, 86 905 and 402 220 individuals were categorized as with and without periodontal disease, respectively. Cox hazard analysis indicated that the presence of periodontal disease was an independent predictor of the occurrence of composite outcomes of inflammatory arthritides, which was also consistent for RA and AS. Significant associations were found to be consistent in the four Cox models and were replicated even when different criteria were used to define periodontal disease. Subgroup analyses indicated that periodontal disease was associated with an increased RA risk in those aged <60 years, and this risk was persistent for both male and female patients and for patients with seropositive/seronegative RA.

CONCLUSION

Self-reported periodontal disease is associated with inflammatory arthritides incidence in participants included in the UK Biobank, particularly for RA and AS. Higher clinical attention and optimal dental care in patients with signs of periodontal disease may be recommended for early disease detection and for reducing this risk.

Exploring the causal relationship between inflammatory cytokines and inflammatory arthritis: A Mendelian randomization study

OBJECTIVES

Previous studies have reported an association between inflammatory cytokines and inflammatory arthritis, including Ankylosing spondylitis (AS), rheumatoid arthritis (RA), and psoriatic arthritis (PsA). This study aims to explore the causal relationship between inflammatory cytokines and AS, RA, and PsA using Mendelian randomization (MR).

METHODS

We conducted a bidirectional two-sample MR analysis using genetic summary data from a publicly available genome-wide association study (GWAS) that included 41 genetic variations of inflammatory cytokines, as well as genetic variant data for AS, RA, and PsA from the FinnGen consortium. The main analysis method used was Inverse variance weighted (IVW) to investigate the causal relationship between exposure and outcome. Additionally, other methods such as MR Egger, weighted median (WM), simple mode, and weighted mode were employed to strengthen the final results. Sensitivity analysis was also performed to ensure the reliability of the findings.

RESULTS

The results showed that macrophage colony-stimulating factor (MCSF) was associated with an increased risk of AS (OR = 1.163, 95 % CI = 1.016-1.33, p = 0.028). Conversely, high levels of TRAIL and beta nerve growth factor (β-NGF) were associated with a decreased risk of AS (OR = 0.892, 95 % CI = 0.81-0.982, p = 0.002; OR = 0.829, 95 % CI = 0.696-0.988, p = 0.036). Four inflammatory cytokines were found to be associated with an increased risk of PsA: vascular endothelial growth factor (VEGF) (OR = 1.161, 95 % CI = 1.057-1.275, p = 0.002); Interleukin 12p70 (IL12p70) (OR = 1.189, 95 % CI = 1.049-1.346, p = 0.007); IL10 (OR = 1.216, 95 % CI = 1.024-1.444, p = 0.026); IL13 (OR = 1.159, 95 % CI = 1.05-1.28, p = 0.004). Interleukin 1 receptor antagonist (IL-1rα) was associated with an increased risk of seropositive RA (OR = 1.181, 95 % CI = 1.044-1.336, p = 0.008). Similarly, genetic susceptibility to inflammatory arthritis was found to be causally associated with multiple inflammatory cytokines. Lastly, the sensitivity analysis supported the robustness of these findings.

CONCLUSIONS

This study provides additional insights into the relationship between inflammatory cytokines and inflammatory arthritis, and may offer new clues for the etiology, diagnosis, and treatment of inflammatory arthritis.

Unravelling the immunobiology of innate lymphoid cells (ILCs): Implications in health and disease

Innate lymphoid cells (ILCs), a growing class of immune cells, imitate the appearance and abilities of T cells. However, unlike T cells, ILCs lack acquired antigen receptors, and they also do not undergo clonal selection or proliferation in response to antigenic stimuli. Despite lacking antigen-specific receptors, ILCs respond quickly to signals from infected or damaged tissues and generate an array of cytokines that regulate the development of adaptive immune response. ILCs can be categorized into four types based on their signature cytokines and transcription factors: ILC1, ILC2, ILC3 (including Lymphoid Tissue inducer- LTi cells), and regulatory ILCs (ILCregs). ILCs play key functions in controlling and resolving inflammation, and variations in their proportion are linked to various pathological diseases including cancer, gastrointestinal, pulmonary, and skin diseases. We highlight current advancements in the biology and classification of ILCs in this review. Additionally, we provide a thorough overview of their contributions to several inflammatory bone-related pathologies, including osteoporosis, rheumatoid arthritis, periodontitis, and ankylosing spondylitis. Understanding the multiple functions of ILCs in both physiological and pathological conditions will further mobilize future research towards targeting ILCs for therapeutic purposes.

A novel drug combination of Tofacitinib and Iguratimod alleviates rheumatoid arthritis and secondary osteoporosis

BACKGROUND

The inadequate response of some patients with rheumatoid arthritis (RA) to current therapies is an issue that needs to be addressed. Patients with refractory RA (RRA) are often accompanied by high Tumor necrosis factor (TNF) expression. We evaluated the synergistic therapeutic effects of the combination of Iguratimod (IGU) and Tofacitinib (TOF) on RRA and secondary osteoporosis.

METHODS

Pathological changes in the ankle joints of collagen-induced arthritis (CIA) + TNF model rats were assessed using hematoxylin and eosin (HE) staining. Immunohistochemistry (IHC) and immunofluorescence (IF) were used to evaluate pyroptosis-related protein levels in the synovial tissues. Moreover, the knee joint was investigated by performing HE staining, IHC, and micro-computed tomography. Furthermore, in vitro, western blotting and enzyme-linked immunosorbent assay (ELISA) were performed to detect the effects of TOF and IGU on TNF-α-induced pyroptosis in fibroblast-like synoviocytes of RA.

RESULTS

After treatment with TOF and/or IGU, the arthritis scores, inflammatory cell infiltration in synovial tissues, and levels of interleukin (IL)-18, IL-1β, and IL-6 in the plasma were remarkably increased in the CIA + TNF model and dramatically decreased in the combination group. The expression of pyroptosis-related proteins was significantly lower in the combination group than in the CIA + TNF group, and a consistent trend was observed in vitro. Bone destruction was significantly alleviated, and the bone turnover rate was remarkably increased in the combination group compared to that in the CIA + TNF model.

CONCLUSION

TOF + IGU alleviated the severity of RRA in the CIA + TNF rat model, relieving joint inflammation, reducing bone erosion, and suppressing pyroptosis. The combined application of TOF and IGU may have a superimposed therapeutic effect on RRA and secondary osteoporotic bone remodeling.

The Independent Value of Neutrophil to Lymphocyte Ratio in Gouty Arthritis: A Narrative Review

Since the incidence of gouty arthritis (GA) exhibits yearly increases, accurate assessment and early treatment have significant values for improving disease conditions and monitoring prognosis. Neutrophil to lymphocyte ratio (NLR) is a common indicator in blood routine, which has the characteristics of easy access and low cost. In recent years, NLR has been proven to be an effective indicator for guiding the diagnosis, treatment, and prognosis of various diseases. Moreover, NLR has varying degrees of relationship with various inflammatory biomarkers, which can affect and reflect the inflammatory response in the body. This paper reviews the independent value of NLR for GA and its underlying molecular pathological mechanisms, intending to contribute to the further application of NLR.

Uncovering the Underworld of Axial Spondyloarthritis

Axial spondyloarthritis (axial-SpA) is a multifactorial disease characterized by inflammation in sacroiliac joints and spine, bone reabsorption, and aberrant bone deposition, which may lead to ankylosis. Disease pathogenesis depends on genetic, immunological, mechanical, and bioenvironmental factors. HLA-B27 represents the most important genetic factor, although the disease may also develop in its absence. This MHC class I molecule has been deeply studied from a molecular point of view. Different theories, including the arthritogenic peptide, the unfolded protein response, and HLA-B27 homodimers formation, have been proposed to explain its role. From an immunological point of view, a complex interplay between the innate and adaptive immune system is involved in disease onset. Unlike other systemic autoimmune diseases, the innate immune system in axial-SpA has a crucial role marked by abnormal activity of innate immune cells, including γδ T cells, type 3 innate lymphoid cells, neutrophils, and mucosal-associated invariant T cells, at tissue-specific sites prone to the disease. On the other hand, a T cell adaptive response would seem involved in axial-SpA pathogenesis as emphasized by several studies focusing on TCR low clonal heterogeneity and clonal expansions as well as an interindividual sharing of CD4/8 T cell receptors. As a result of this immune dysregulation, several proinflammatory molecules are produced following the activation of tangled intracellular pathways involved in pathomechanisms of axial-SpA. This review aims to expand the current understanding of axial-SpA pathogenesis, pointing out novel molecular mechanisms leading to disease development and to further investigate potential therapeutic targets.

Th2 Cytokines (Interleukin-5 and -9) Polymorphism Affects the Response to Anti-TNF Treatment in Polish Patients with Ankylosing Spondylitis

Ankylosing spondylitis (AS) is an inflammatory disease that belongs to the spondyloarthritis family. IL-5 and IL-9 belong to the group of Th2 cytokines of anti-inflammatory nature. Polymorphisms in their coding genes have been so far associated with various inflammatory diseases, but there are no reports regarding their involvement in AS pathogenesis to date. The purpose of the study was to investigate relationships between IL5 and IL9 genetic variants with AS susceptibility, clinical parameters as well as response to therapy with TNF inhibitors. In total 170 patients receiving anti-TNF therapy and 218 healthy controls were enrolled in the study. The genotyping of IL5 rs2069812 (A > G) and IL9 rs2069885 (G > A) single nucleotide polymorphisms was performed using the Real-Time PCR method based on LightSNiP kits assays. The present study demonstrated significant relationships between IL5 rs2069812 and IL9 rs2069885 polymorphisms and response to anti-TNF therapy. Presence of the IL5 rs2069812 A allele in patients positively correlated with better response to treatment (p = 0.022). With regard to IL9 rs2069885, patients carrying the A allele displayed better outcomes in anti-TNF therapy (p = 0.046). In addition, IL5 rs2069812 A and IL9 rs2069885 A alleles were associated with lower CRP and VAS values. The obtained results may indicate a significant role for IL-5 and IL-9 in the course of AS and response to anti-TNF therapy.

Inhibition of Histone H3 Lysine-27 Demethylase Activity Relieves Rheumatoid Arthritis Symptoms via Repression of IL6 Transcription in Macrophages

Rheumatoid arthritis (RA) occurs in about 5 per 1,000 people and can lead to severe joint damage and disability. However, the knowledge of pathogenesis and treatment for RA remains limited. Here, we found that histone demethylase inhibitor GSK-J4 relieved collagen induced arthritis (CIA) symptom in experimental mice model, and the underlying mechanism is related to epigenetic transcriptional regulation in macrophages. The role of epigenetic regulation has been introduced in the process of macrophage polarization and the pathogenesis of inflammatory diseases. As a repressive epigenetic marker, tri-methylation of lysine 27 on histone H3 (H3K27me3) was shown to be important for transcriptional gene expression regulation. Here, we comprehensively analyzed H3K27me3 binding promoter and corresponding genes function by RNA sequencing in two differentially polarized macrophage populations. The results revealed that H3K27me3 binds on the promoter regions of multiple critical cytokine genes and suppressed their transcription, such as IL6, specifically in M-CSF derived macrophages but not GM-CSF derived counterparts. Our results may provide a new approach for the treatment of inflammatory and autoimmune disorders.

Emerging Role of Eosinophils in Resolution of Arthritis

Eosinophils are a minor component of circulating granulocytes, which are classically viewed as end-stage effector cells in host defense against helminth infection and promoting allergic responses. However, a growing body of evidence has emerged showing that eosinophils are versatile leukocytes acting as an orchestrator in the resolution of inflammation. Rheumatoid arthritis (RA) is the most common chronic inflammatory disease characterized by persistent synovitis that hardly resolves spontaneously. Noteworthy, a specific population of eosinophils, that is, regulatory eosinophils (rEos), was identified in the synovium of RA patients, especially in disease remission. Mechanistically, the rEos in the synovium display a unique pro-resolving signature that is distinct from their counterpart in the lung. Herein, we summarize the latest understanding of eosinophils and their emerging role in promoting the resolution of arthritis. This knowledge is crucial to the design of new approaches to rebalancing immune homeostasis in RA, considering that current therapies are centered on inhibiting pro-inflammatory cytokines and mediators rather than fostering the resolution of inflammation.

Effect of Micro-/Nanoparticle Hybrid Hydrogel Platform on the Treatment of Articular Cartilage-Related Diseases

Joint diseases that mainly lead to articular cartilage injury with prolonged severe pain as well as dysfunction have remained unexplained for many years. One of the main reasons is that damaged articular cartilage is unable to repair and regenerate by itself. Furthermore, current therapy, including drug therapy and operative treatment, cannot solve the problem. Fortunately, the micro-/nanoparticle hybrid hydrogel platform provides a new strategy for the treatment of articular cartilage-related diseases, owing to its outstanding biocompatibility, high loading capability, and controlled release effect. The hybrid platform is effective for controlling symptoms of pain, inflammation and dysfunction, and cartilage repair and regeneration. In this review, we attempt to summarize recent studies on the latest development of micro-/nanoparticle hybrid hydrogel for the treatment of articular cartilage-related diseases. Furthermore, some prospects are proposed, aiming to improve the properties of the micro-/nanoparticle hybrid hydrogel platform so as to offer useful new ideas for the effective and accurate treatment of articular cartilage-related diseases.

Attenuation of rheumatoid arthritis through the inhibition of caspase3/GSDME-mediated pyroptosis induced by TNF-α

Objective

To determine the role of gasdermin E (GSDME)–mediated pyroptosis in the pathogenesis and progression of rheumatoid arthritis (RA), and to explore the potential of GSDME as a therapeutic target in RA.

Methods

The expression and activation of caspase 3 and GSDME in the synovium, macrophages, and monocytes of RA patients were determined by immunohistochemistry, immunofluorescence, and Western blot analysis. The correlation of activated GSDME with RA disease activity was evaluated. The pyroptotic ability of monocytes from RA patients was tested, and the effect of tumor necrosis factor (TNF) on caspase 3/GSDME‐mediated pyroptosis of monocytes and macrophages was investigated. In addition, collagen‐induced arthritis (CIA) was induced in mice lacking Gsdme, and the incidence and severity of arthritis were assessed.

Results

Compared to cells from healthy controls, monocytes and synovial macrophages from RA patients showed increased expression of activated caspase 3, GSDME, and the N‐terminal fragment of GSDME (GSDME‐N). The expression of GSDME‐N in monocytes from RA patients correlated positively with disease activity. Monocytes from RA patients with higher GSDME levels were more susceptible to pyroptosis. Furthermore, TNF induced pyroptosis in monocytes and macrophages by activating the caspase 3/GSDME pathway. The use of a caspase 3 inhibitor and silencing of GSDME significantly blocked TNF‐induced pyroptosis. Gsdme deficiency effectively alleviated arthritis in a mouse model of CIA.

Conclusion

These results support the notion of a pathogenic role of GSDME in RA and provide an alternative mechanism for RA pathogenesis involving TNF, which activates GSDME‐mediated pyroptosis of monocytes and macrophages in RA. In addition, targeting GSDME might be a potential therapeutic approach for RA.

NK Cells in Autoimmune Diseases: Protective or Pathogenic?

Autoimmune diseases generally result from the loss of self-tolerance (i.e., failure of the immune system to distinguish self from non-self), and are characterized by autoantibody production and hyperactivation of T cells, which leads to damage of specific or multiple organs. Thus, autoimmune diseases can be classified as organ-specific or systemic. Genetic and environmental factors contribute to the development of autoimmunity. Recent studies have demonstrated the contribution of innate immunity to the onset of autoimmune diseases. Natural killer (NK) cells, which are key components of the innate immune system, have been implicated in the development of multiple autoimmune diseases such as systemic lupus erythematosus, type I diabetes mellitus, and autoimmune liver disease. However, NK cells have both protective and pathogenic roles in autoimmunity depending on the NK cell subset, microenvironment, and disease type or stage. In this work, we review the current knowledge of the varied roles of NK cell subsets in systemic and organic-specific autoimmune diseases and their clinical potential as therapeutic targets.