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Background: Bivalent regions of chromatin (BvCR) are characterized by trimethylated lysine 4 (H3K4me3) and lysine 27 on histone H3 (H3K27me3) deposition which aid gene expression control during cell differentiation. The role of BvCR in post-transcriptional DNA damage response remains unidentified. Oncoprotein survivin binds chromatin and mediates IFNγ effects in CD4 + cells. In this study, we explored the role of BvCR in DNA damage response of autoimmune CD4 + cells in rheumatoid arthritis (RA)., Methods: We performed deep sequencing of the chromatin bound to survivin, H3K4me3, H3K27me3, and H3K27ac, in human CD4 + cells and identified BvCR, which possessed all three histone H3 modifications. Protein partners of survivin on chromatin were predicted by integration of motif enrichment analysis, computational machine-learning, and structural modeling, and validated experimentally by mass spectrometry and peptide binding array. Survivin-dependent change in BvCR and transcription of genes controlled by the BvCR was studied in CD4 + cells treated with survivin inhibitor, which revealed survivin-dependent biological processes. Finally, the survivin-dependent processes were mapped to the transcriptome of CD4 + cells in blood and in synovial tissue of RA patients and the effect of modern immunomodulating drugs on these processes was explored., Results: We identified that BvCR dominated by H3K4me3 (H3K4me3-BvCR) accommodated survivin within cis-regulatory elements of the genes controlling DNA damage. Inhibition of survivin or JAK-STAT signaling enhanced H3K4me3-BvCR dominance, which improved DNA damage recognition and arrested cell cycle progression in cultured CD4 + cells. Specifically, BvCR accommodating survivin aided sequence-specific anchoring of the BRG1/SWI chromatin-remodeling complex coordinating DNA damage response. Mapping survivin interactome to BRG1/SWI complex demonstrated interaction of survivin with the subunits anchoring the complex to chromatin. Co-expression of BRG1, survivin and IFNγ in CD4 + cells rendered complete deregulation of DNA damage response in RA. Such cells possessed strong ability of homing to RA joints. Immunomodulating drugs inhibited the anchoring subunits of BRG1/SWI complex, which affected arthritogenic profile of CD4 + cells., Conclusions: BvCR execute DNA damage control to maintain genome fidelity in IFN-activated CD4 + cells. Survivin anchors the BRG1/SWI complex to BvCR to repress DNA damage response. These results offer a platform for therapeutic interventions targeting survivin and BRG1/SWI complex in autoimmunity., (© 2024. The Author(s).)

Rheumatoid arthritis (RA) is a systemic autoimmune disorder that severely compromises joint health. The primary therapeutic strategy for advanced RA aims to inhibit joint inflammation. However, the nonspecific distribution of pharmacological agents has limited therapeutic efficacy and heightens the risks associated with RA treatment. To address this issue, we developed mesenchymal stem cell (MSC)-based biomimetic liposomes, termed MSCsome, which were composed of a fusion between MSC membranes and liposomes. MSC some with relatively simple preparation method effectively enhanced the targeting efficiency of drug to diseased joints. Interaction between lymphocyte function-associated antigen-1 and intercellular adhesion molecule-1 enhanced the affinity of the MSCsome for polarized macrophages, thereby improving its targeting capability to affected joints. The effective targeted delivery facilitated drug accumulation in joints, resulting in the significant inhibition of the inflammation, as well as protection and repair of the cartilage. In conclusion, this study introduced MSCsome as a promising approach for the effective treatment of advanced RA, providing a novel perspective on targeted drug delivery therapy for inflammatory diseases.

miRNAs constitute fine-tuners of gene expression and are implicated in a variety of diseases spanning from inflammation to cancer. miRNA expression is deregulated in rheumatoid arthritis (RA); however, their specific role in key arthritogenic cells such as the synovial fibroblast (SF) remains elusive. Previous studies have shown that Mir221/222 expression is upregulated in RA SFs. Here, we demonstrate that TNF and IL-1β but not IFN-γ activated Mir221 /222 gene expression in murine SFs. SF-specific overexpression of Mir221/222 in huTNFtg mice led to further expansion of SFs and disease exacerbation, while its total ablation led to reduced SF expansion and attenuated disease. Mir221/222 overexpression altered the SF transcriptional profile igniting pathways involved in cell cycle and ECM (extracellular matrix) regulation. Validation of targets of Mir221/222 revealed cell cycle inhibitors Cdkn1b and Cdkn1c , as well as the epigenetic regulator Smarca1 . Single-cell ATAC-seq data analysis revealed increased Mir221 /222 gene activity in pathogenic SF subclusters and transcriptional regulation by Rela , Relb , Junb , Bach1 , and Nfe2l2 . Our results establish an SF-specific pathogenic role of Mir221/222 in arthritis and suggest that its therapeutic targeting in specific subpopulations could lead to novel fibroblast-targeted therapies., Competing Interests: FR, CT, DK, DP, AP, MS, AL, PC, TM, YP, MF, MA, GK No competing interests declared, NK, MD affiliated with Biomedcode Hellas SA. The author has no financial interests to declare, (© 2024, Roumelioti et al.)

Rheumatoid arthritis (RA) remains a challenging chronic autoimmune disorder characterized by persistent joint inflammation and damage. While modern regenerative strategies, encompassing cell/stem cell-based therapies, gene therapy, and tissue engineering, have advanced tissue repair efforts, a definitive cure for RA remains elusive. Consequently, there is growing interest in developing targeted therapies that directly address the underlying mechanisms driving RA pathogenesis, such as extracellular vesicles (EVs). These small membrane-bound particles can modulate immune responses within the inflammatory microenvironment of damaged cartilage. To launch the clinical potential of EVs, they can be isolated from various cell types through several techniques. EVs can carry various bioactive molecules and anti-inflammatory or pro-regenerative drugs, deliver them directly to the affected joints, and affect the behavior of injured cells, making them a compelling choice for targeted therapy and drug delivery in RA patients. However, there are still several challenges and limitations associated with EV-based therapy, including the absence of standardized protocols for EV isolation, characterization, and delivery. This review provides a comprehensive overview of the cellular sources of EVs in RA and delves into their therapeutic potential and the hurdles they must overcome., (© 2024. The Author(s).)

Objective: The objective is to characterize transcriptomic profiles and immune cell composition and distribution in juvenile idiopathic arthritis (JIA) synovial biopsies, assess for associations of these features with clinical parameters, and compare JIA and rheumatoid arthritis (RA) synovial features., Methods: RNA sequencing (RNASeq) was performed on 24 samples, with pathway analysis and inference of relative abundance of immune cell subsets based on gene expression data. Two multiplex fluorescence immunohistochemistry (IHC) panels were performed on 28 samples (including 13 on which RNASeq was performed), staining for CD206 - classical and CD206 + nonclassical macrophages, and CD8 + and CD4 + T and B lymphocytes. Data were compared to a published series of early RA synovial biopsies., Results: Pathway analysis of the most variably expressed genes (n = 339) identified a B and plasma cell signature as the main driver of heterogeneity in JIA synovia, with strong overlap between JIA and RA synovitis. Multiplex IHC confirmed heterogeneity of immune cell infiltration. M1-like macrophage-rich synovial lining was associated with greater lining hypertrophy and higher (CD45 + ) pan-immune cell and CD8 + T cell infiltration., Conclusion: Our study indicates significant similarities between JIA and RA synovitis. Similar to RA, JIA synovia may be broadly categorized into two groups: (1) those with an inflammatory/adaptive immune transcriptomic signature, M1-like macrophage and CD8 + T cell infiltration, and thicker, M1-like macrophage-rich synovial lining, and (2) those with an M2-like macrophage transcriptomic signature, greater M2/M1-like macrophage ratios, and thinner, M2-like macrophage-rich synovial lining. Synovial features were not significantly associated with clinical parameters, likely because of group size and heterogeneity., (© 2024 The Author(s). Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Healing bone erosions in rheumatoid arthritis (RA) remains greatly challenging via biomaterial strategies. Given the unsuccessful innate bone erosion healing due to an inflammatory disorder, over-activated osteoclasts, and impaired osteoblasts differentiation, RA pathogenesis-guided engineering of an innovative hydrogel platform is needed for remodeling osteoimmune and osteogenic microenvironment of bone erosion healing. Herein, in situ adaptable and injectable interpenetrating polymer network (IPN) hydrogel is developed through an ingenious combination of a bio-orthogonal reaction between hyaluronic acid (HA) and collagen, along with effective electrostatic interactions leveraging bisphosphonate (BP)-functionalized HA macromers (HABP) and nanorod shaped zinc (Zn)-doped biphasic calcium phosphate (ZnBCP). IPN hydrogel exhibits exceptional adaptability to the local shape complexity at bone erosions, and by integrating ZnBCP and HABP, a multi-stage releasing platform is engineered, facilitating controlled cargo delivery for remodeling more anti-inflammatory M2 cells and reducing over-activated osteoclastic activities, thereby reconstructing the bone regeneration microenvironment. Sustainedly co-delivering multiple ions (calcium and phosphate) can display excellent osteogenic properties and be conducive to the bone formation process, by effects of osteogenesis-associated cell differentiation. Overall, the introduced bioactive IPN hydrogel therapy remodels the osteoimmune environment by synergistic pro-inflammation-resolving, osteogenesis, and anti-osteoclastic activities, displaying excellent bone reconstruction in the collagen-induced arthritis rabbit model., (© 2024 Wiley‐VCH GmbH.)

Regulation of neutrophil activation is critical for disease control. Neutrophil extracellular traps (NETs), which are web-like structures composed of DNA and neutrophil-derived proteins, are formed following pro-inflammatory signals; however, if this process is uncontrolled, NETs contribute to disease pathogenesis, exacerbating inflammation and host tissue damage 1,2 . Here we show that myeloid inhibitory C-type lectin-like (MICL), an inhibitory C-type lectin receptor, directly recognizes DNA in NETs; this interaction is vital to regulate neutrophil activation. Loss or inhibition of MICL functionality leads to uncontrolled NET formation through the ROS-PAD4 pathway and the development of an auto-inflammatory feedback loop. We show that in the context of rheumatoid arthritis, such dysregulation leads to exacerbated pathology in both mouse models and in human patients, where autoantibodies to MICL inhibit key functions of this receptor. Of note, we also detect similarly inhibitory anti-MICL autoantibodies in patients with other diseases linked to aberrant NET formation, including lupus and severe COVID-19. By contrast, dysregulation of NET release is protective during systemic infection with the fungal pathogen Aspergillus fumigatus. Together, we show that the recognition of NETs by MICL represents a fundamental autoregulatory pathway that controls neutrophil activity and NET formation., (© 2024. The Author(s).)

Ferroptosis is a type of programmed cell death driven by iron-dependent lipid peroxidation. The TNF-mediated biosynthesis of glutathione has been shown to protect synovial fibroblasts from ferroptosis in the hyperplastic synovium. Ferroptosis induction provides a novel therapeutic approach for rheumatoid arthritis (RA) by reducing the population of synovial fibroblasts. The beginning and maintenance of synovitis in RA are significantly influenced by macrophages, as they generate cytokines that promote inflammation and contribute to the destruction of cartilage and bone. However, the vulnerability of macrophages to ferroptosis in RA remains unclear. In this study, we found that M2 macrophages are more vulnerable to ferroptosis than M1 macrophages in the environment of the arthritis synovium with a high level of iron, leading to an imbalance in the M1/M2 ratio. During ferroptosis, HMGB1 released by M2 macrophages interacts with TLR4 on M1 macrophages, which in turn triggers the activation of STAT3 signaling in M1 macrophages and contributes to the inflammatory response. Knockdown of TLR4 decreased the level of cytokines induced by HMGB1 in M1 macrophages. The ferroptosis inhibitor liproxstatin-1 (Lip-1) started at the presymptomatic stage in collagen-induced arthritis (CIA) model mice, and GPX4 overexpression in M2 macrophages at the onset of collagen antibody-induced arthritis (CAIA) protected M2 macrophages from ferroptotic cell death and significantly prevented the development of joint inflammation and destruction. Thus, our study demonstrated that M2 macrophages are vulnerable to ferroptosis in the microenvironment of the hyperplastic synovium and revealed that the HMGB1/TLR4/STAT3 axis is critical for the ability of ferroptotic M2 macrophages to contribute to the exacerbation of synovial inflammation in RA. Our findings provide novel insight into the progression and treatment of RA., Competing Interests: Declaration of competing interest The authors have no conflict of interest relevant to this study to declare., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Synovitis is characterized by a distinctmetabolic profile featuring the accumulation of lactate, a byproduct of cellular metabolism within inflamed joints. This study reveals that the activation of the CD31 signal by lactate instigates a metabolic shift, specifically initiating endothelial cell autophagy. This adaptive process plays a pivotal role in fulfilling the augmented energy and biomolecule demands associated with the formation of new blood vessels in the synovium of Rheumatoid Arthritis (RA). Additionally, the amino acid substitutions in the CD31 cytoplasmic tail at the Y663F and Y686F sites of the immunoreceptor tyrosine-based inhibitory motifs (ITIM) alleviate RA. Mechanistically, this results in the downregulation of glycolysis and autophagy pathways. These findings significantly advance our understanding of potential therapeutic strategies for modulating these processes in synovitis and, potentially, other autoimmune diseases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Rheumatoid arthritis (RA) is a common autoimmune condition and chronic inflammatory disease, mostly affecting synovial joints. The complex pathogenesis of RA is supportive of high morbidity, disability, and mortality rates. Pathological changes a common characteristic in RA synovial tissue is attributed to the inadequacy of apoptotic pathways. In that regard, apoptotic pathways have been the center of attention in RA therapeutic approaches. As the regulators in the complex network of apoptosis, microRNAs (miRNAs) are found to be vital modulators in both intrinsic and extrinsic pathways through altering their regulatory genes. Indeed, miRNA, a member of the family of non-coding RNAs, are found to be an important player in not even apoptosis, but proliferation, gene expression, signaling pathways, and angiogenesis. Aberrant expression of miRNAs is implicated in attenuation and/or intensification of various apoptosis routes, resulting in culmination of human diseases including RA. Considering the need for more studies focused on the underlying mechanisms of RA in order to elevate the unsatisfactory clinical treatments, this study is aimed to delineate the importance of apoptosis in the pathophysiology of this disease. As well, this review is focused on the critical role of miRNAs in inducing or inhibiting apoptosis of RA-synovial fibroblasts and fibroblast-like synoviocytes and how this mechanism can be exerted for therapeutic purposes for RA., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Fahad Alsaikhan reports financial support was provided by Prince Sattam bin Abdulaziz University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

The management of rheumatic diseases has noticeably changed in recent years with the development of targeted therapeutic agents, namely, biological disease-modifying antirheumatic drugs. Identifying essential signaling pathways and factors crucial for the development and progression of these diseases remains a significant challenge. Therapy could be used to delay the onset or reduce harm. The endocannabinoid system's presence within the synovium can be identified as a suggested target for therapeutic interventions due to its role in modulating pain, inflammation, and joint metabolism. This review brings together the most pertinent information concerning the actions of the endocannabinoid system present in inflamed synovial tissue and its interaction with phytocannabinoids and synthetic cannabinoids, which can be used from a therapeutic perspective to minimize the inflammatory and pain processes typical of osteoarthritis and rheumatoid arthritis.

Rheumatoid arthritis (RA) is a complex immune-mediated inflammatory disorder in which patients suffer from inflammatory-erosive arthritis. Recent advances on histopathology heterogeneity of RA synovial tissue revealed three distinct phenotypes based on cellular composition (pauci-immune, diffuse and lymphoid), suggesting that distinct etiologies warrant specific targeted therapy which motivates a need for cost effective phenotyping tools in preclinical and clinical settings. To this end, we developed an automated multi-scale computational pathotyping (AMSCP) pipeline for both human and mouse synovial tissue with two distinct components that can be leveraged together or independently: (1) segmentation of different tissue types to characterize tissue-level changes, and (2) cell type classification within each tissue compartment that assesses change across disease states. Here, we demonstrate the efficacy, efficiency, and robustness of the AMSCP pipeline as well as the ability to discover novel phenotypes. Taken together, we find AMSCP to be a valuable cost-effective method for both pre-clinical and clinical research., (© 2024. The Author(s).)

Objective: Rheumatoid Arthritis (RA) often exhibits suboptimal treatment response despite early diagnosis and treatment. This study aimed to analyze Early Rheumatoid Arthritis (ERA) synovial biopsies through histology and immunohistochemistry (IHC) to identify predictive factors for treatment response to Methotrexate (MTX)., Methods: 140 ERA patients from the UCLouvain Arthritis Cohort underwent synovial biopsy and were monitored after initiating Disease-Modifying Antirheumatic Drug (DMARD) therapy. Histological features [Synovial Hyperplasia, Fibrinoid Necrosis (FN), Hypervascularization and Inflammatory Infiltrate] and IHC (CD3, CD20, CD138, CD68) were each semi-quantitatively assessed on a 0-3 scale with 7 levels., Results: A strong association was observed between synovial CD68 and Fibrinoid Necrosis scores [r = 0.44 (0.27 - 0.56); p < 0.0001]. CD68 correlated with C-Reactive Protein (CRP), DAS28, SDAI and CDAI. Fibrinoid Necrosis score correlated with CRP and DAS28. Patients were then categorized as CD68Necrosis HIGH (CD68 + Necrosis ≥ 3) and CD68Necrosis LOW (CD68 + Necrosis < 3). CD68Necrosis HIGH exhibited higher pre-treatment disease activity [5.48 (1.6) versus 4.8 (1.7); p = 0.03] and a greater fall in DAS28 [1.99 (2.06) versus 1.1 (2.27), p = 0.03], SDAI [21.45 (IQR 23.3) versus 11.65 (IQR 17.5); p = 0.003] and CDAI [16 [14.9] versus 10.5 (20.1), p = 0.04]. CD68Necrosis HIGH patients had a higher EULAR Moderate/Good Response rate. CD68Necrosis score was incorporated into a probability matrix model together with clinical features (SJC44 and DAS28) to predict achieving a Moderate/Good EULAR Response Criteria at 3 months with a good performance (AUC 0.724)., Conclusion: FN and CD68 + in ERA synovial biopsies identify patients with higher disease activity and predict a better treatment response at three months. A model including synovial CD68 and fibrinoid necrosis with baseline clinical features predicts EULAR response at 3 months., (© 2024. The Author(s).)

Rheumatoid arthritis (RA) is a chronic autoimmune disease with a complex etiology. Neutrophil extracellular traps (NETs are NETwork protein structures activated by neutrophils to induce the cleavage and release of DNA-protein complexes). Current studies have shown the critical involvement of NETs in the progression of autoimmune diseases, Neutrophils mostly gather in the inflammatory sites of patients and participate in the pathogenesis of autoimmune diseases in various ways. NETs, as the activated state of neutrophils, have attracted much attention in immune diseases. Many molecules released in NETs are targeted autoantigens in autoimmune diseases, such as histones, citrulline peptides, and myeloperoxidase. All of these suggest that NETs have a direct causal relationship between the production of autoantigens and autoimmune diseases. For RA in particular, as a disorder of the innate and adaptive immune response, the pathogenesis of RA is inseparable from the generation of RA. In this article, we investigate the emerging role of NETs in the pathogenesis of RA and suggest that NETs may be an important target for the treatment of inflammatory autoimmune diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Cao, Xiao, Hong and Zhu.)

Rheumatoid arthritis (RA) and arthrofibrosis (AF) are both chronic synovial hyperplasia diseases that result in joint stiffness and contractures. They shared similar symptoms and many common features in pathogenesis. Our study aims to perform a comprehensive analysis between RA and AF and identify novel drugs for clinical use. Based on the text mining approaches, we performed a correlation analysis of 12 common joint diseases including arthrofibrosis, gouty arthritis, infectious arthritis, juvenile idiopathic arthritis, osteoarthritis, post infectious arthropathies, post traumatic osteoarthritis, psoriatic arthritis, reactive arthritis, rheumatoid arthritis, septic arthritis, and transient arthritis. 5 bulk sequencing datasets and 4 single-cell sequencing datasets of RA and AF were integrated and analyzed. A novel drug repositioning method was found for drug screening, and text mining approaches were used to verify the identified drugs. RA and AF performed the highest gene similarity (0.77) and functional ontology similarity (0.84) among all 12 joint diseases. We figured out that they share the same key pathogenic cell including CD34 + sublining fibroblasts (CD34-SLF) and DKK3 + sublining fibroblasts (DKK3-SLF). Potential therapeutic target database (PTTD) was established with the differential expressed genes (DEGs) of these key pathogenic cells. Based on the PTTD, 15 potential drugs for AF and 16 potential drugs for RA were identified. This work provides a new perspective on AF and RA study which enhances our understanding of their pathogenesis. It also shed light on their underlying mechanism and open new avenues for drug repositioning studies., (© 2024. The Author(s).)

Heparan sulfate (HS) proteoglycans are important regulators of cellular responses to soluble mediators such as chemokines, cytokines and growth factors. We profiled changes in expression of genes encoding HS core proteins, biosynthesis enzymes and modifiers during macrophage polarisation, and found that the most highly regulated gene was Sulf2, an extracellular HS 6-O-sulfatase that was markedly downregulated in response to pro-inflammatory stimuli. We then generated Sulf2 +/- bone marrow chimeric mice and examined inflammatory responses in antigen-induced arthritis, as a model of rheumatoid arthritis. Resolution of inflammation was impaired in myeloid Sulf2 +/- chimeras, with elevated joint swelling and increased abundance of pro-arthritic Th17 cells in synovial tissue. Transcriptomic and in vitro analyses indicated that Sulf2 deficiency increased type I interferon signaling in bone marrow-derived macrophages, leading to elevated expression of the Th17-inducing cytokine IL6. This establishes that dynamic remodeling of HS by Sulf2 limits type I interferon signaling in macrophages, and so protects against Th17-driven pathology., (© 2024. The Author(s).)

TNF is a potent cytokine known for its involvement in physiology and pathology. In Rheumatoid Arthritis (RA), persistent TNF signals cause aberrant activation of synovial fibroblasts (SFs), the resident cells crucially involved in the inflammatory and destructive responses of the affected synovial membrane. However, the molecular switches that control the pathogenic activation of SFs remain poorly defined. Cyld is a major component of deubiquitination (DUB) machinery regulating the signaling responses towards survival/inflammation and programmed necrosis that induced by cytokines, growth factors and microbial products. Herein, we follow functional genetic approaches to understand how Cyld affects arthritogenic TNF signaling in SFs. We demonstrate that in spontaneous and induced RA models, SF-Cyld DUB deficiency deteriorates arthritic phenotypes due to increased levels of chemokines, adhesion receptors and bone-degrading enzymes generated by mutant SFs. Mechanistically, Cyld serves to restrict the TNF-induced hyperactivation of SFs by limiting Tak1-mediated signaling, and, therefore, leading to supervised NF-κB and JNK activity. However, Cyld is not critically involved in the regulation of TNF-induced death of SFs. Our results identify SF-Cyld as a regulator of TNF-mediated arthritis and inform the signaling landscape underpinning the SF responses., (© 2024. The Author(s).)

Purpose: Sinomenine (SIN) is commonly used in Traditional Chinese Medicine (TCM) as a respected remedy for rheumatoid arthritis (RA). Nevertheless, the therapeutic mechanism of SIN in RA remains incompletely understood. This study aimed to delve into the molecular mechanism of SIN in the treatment of RA., Methods: The potential targets of SIN were predicted using the TCMSP server, STITCH database, and SwissTarget Prediction. Differentially expressed genes (DEGs) in RA were obtained from the GEO database. Enrichment analyses and molecular docking were conducted to explore the potential mechanism of SIN in the treatment of RA. In vitro and in vivo studies were conducted to validate the intervention effects of SIN on rheumatoid arthritis, as determined through network pharmacology analyses., Results: A total of 39 potential targets associated with the therapeutic effects of SIN in RA were identified. Enrichment analysis revealed that these potential targets are primarily enriched in PI3K-Akt signaling pathway, and the molecular docking suggests that SIN may act on specific proteins in the pathway. Experimental results have shown that exposure to SIN inhibits cytokine secretion, promotes apoptosis, reduces metastasis and invasion, and blocks the activation of the PI3K-Akt signaling pathway in RA fibroblast-like synoviocytes (RA-FLS). Moreover, SIN treatment alleviated arthritis-related symptoms and regulated the differentiation of CD4+ T cells in the spleen of collagen-induced arthritis (CIA) mice., Conclusion: By utilizing network pharmacology, molecular modeling, and in vitro/in vivo validation, this study demonstrates that SIN can alleviate RA by inhibiting the PI3K-Akt signaling pathway. These findings enhance the understanding of the therapeutic mechanisms of SIN in RA, offering a stronger theoretical foundation for its future clinical application., Competing Interests: The authors report no conflicts of interest in this work., (© 2024 Liu et al.)

Background: Rheumatoid arthritis (RA) is one autoimmune disease that badly influences the lives of humans. Nuclear factor interleukin 3 (NFIL3) has been elucidated to join into the progression of diversiform diseases. According to a recent report, NFIL3 expression levels are increased in the peripheral blood and synovial tissues of individuals with RA. However, the detailed regulatory impacts of NFIL3 and associated pathways in RA progression need more investigations., Methods: The mRNA and protein expressions were tested through RT-qPCR and western blot. The cell proliferation was evaluated through CCK-8 and EdU assay. The cell apoptosis was measured through flow cytometry. The levels of TNF-α, IL-6, and IL-8 were assessed through ELISA. The cell migration and invasion were tested through Transwell assay., Results: In this study, NFIL3 exhibited higher expression in RA fibroblast-like synoviocytes (interleukin-1β [IL-1β]-triggered MH7A cell model). In addition, knockdown of NFIL3 repressed the growth of IL-1β-mediated MH7A cells. It was also demonstrated that suppressing NFIL3 resulted in reduced inflammatory reactions in IL-1β-mediated MH7A cells. Suppression of NFIL3 alleviated cell migration and invasion in the RA cell model. Ultimately, it was demonstrated that NFIL3 retarded the AMPK/mTOR pathway., Conclusion: This study demonstrated that the inhibition of NFIL3 effectively controlled the AMPK/mTOR pathway, thereby suppressing the overactive proliferation, inflammation, and migration of fibroblast-like synoviocytes in human RA. This discovery implied that NFIL3 can be a serviceable biomarker for RA therapy., (© 2024 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

In this study, we wanted to investigate the effectiveness of combining disease-modifying anti-rheumatic drugs (DMARD) with hyperbaric oxygen therapy (HBOT) in reducing inflammation in a rheumatoid arthritis (RA) model using rats. We divided 56 male Sprague-Dawley rats into seven groups and induced RA using complete Freund's adjuvant. Some groups received HBOT, whereas others were given etanercept or leflunomide. We started the treatment on the 10th day after inducing RA and continued it for 18 days. To evaluate the effectiveness of the treatments, we measured paw swelling and used X-rays to examine the joints before and after the treatment. We also analysed the levels of two inflammatory markers, tumour necrosis factor (TNF)-α and interleukin (IL)-1β, using an enzyme-linked immunosorbent assay. Additionally, we conducted histological analysis and assessed the expressions of anti-IL-1β and anti-TNF-α antibodies. All the treatment groups showed a significant decrease in arthritis scores, paw swelling and levels of TNF-α and IL-1β. The X-ray images revealed improvements in joint structure, and the histopathological analysis showed reduced inflammation and collagen abnormalities. Combining DMARD with HBOT had similar effects to individual therapies, suggesting a cost-effective and potentially safer approach for improving outcomes in rats with RA., (© 2024 The Author(s). Clinical and Experimental Pharmacology and Physiology published by John Wiley & Sons Australia, Ltd.)

Rheumatoid arthritis (RA) is a type of joint injury, which can induce the activation of inflammatory factors and polarization of tissue macrophages. Total phenolics from Laggera alata (TPLA) has been reported to exhibit anti-inflammatory effect in various diseases. However, its specific function in RA is still unknown. Here, the protective properties of TPLA were studied in collagen-induced arthritis (CIA)-induced RA mice. RA mouse model was established through the CIA induction. Arthritis score, hind paw thickness, and the body weight of the RA mice were evaluated in each group. H&E staining was conducted in hind paw and joint tissues for histopathological staining. The distal femur was analyzed by microCT, and bone loss-related indicators were assessed. The expression of macrophage polarization markers was detected by immunofluorescence staining in RA mice. The serum levels of inflammatory markers were determined by enzyme-linked immunosorbent assay (ELISA). TPLA reduced the CIA-induced arthritis score and hind paw thickness in mice. The body weight of the CIA mouse was significantly increased by TPLA treatment. TPLA improved the CIA-induced histopathological changes in the hind paw and joint tissues from the mice. TPLA inhibited the bone loss and alleviated bone destruction in CIA mouse model. TPLA altered the macrophage phenotype from M1 macrophages into M2 in CIA mice. TPLA suppressed the levels of inflammatory markers both in the serum and joint tissues of the CIA mice. TPLA mitigated RA development by suppressing inflammatory reaction through the inhibition of M1 microphage polarization., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: To investigate the impact of IGJ on the proliferation, inflammation, and motility of rheumatoid arthritis (RA) fibroblast-like synoviocytes and elucidate the underlying mechanism., Methods: The expression of IGJ RA fibroblast-like synoviocytes was assessed using immunoblot and qPCR. Cell growth was evaluated using CCK-8 and FCM assays. The effects on inflammatory response were determined by ELISA and immunoblot assays. Cell motility was assessed using transwell and immunoblot assays. The mechanism was further confirmed using immunoblot assays., Results: IGJ expression was found to be elevated in fibroid synovial cells of RA. IGJ ablation inhibited the growth of MH7A cells and suppressed the inflammatory response. Knockdown of IGJ also blocked cell motility. Mechanically, the knockdown of IGJ suppressed the NF-κB axis in MH7A cells., Conclusion: IGJ suppresses RA in fibroblast-like synoviocytes via NF-κB pathway., (© 2024 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

The crucial cellular activities for maintaining normal cell functions heavily rely on the polarity of the endoplasmic reticulum (ER). Understanding how the polarity shifts, particularly in the context of ER autophagy (ER-phagy), holds significant promise for advancing knowledge of disorders associated with ER stress. Herein, a polarity-sensitive fluorescent probe CDI was easily synthesized from the condensation reaction of coumarin and dicyanoisophorone. CDI was composed of coumarin as the electron-donating moiety (D), ethylene and phenyl ring as the π-conjugation bridge, and malononitrile as the electron-accepting moiety (A), forming a typical D-π-A molecular configuration that recognition in the near-infrared (NIR) region. The findings suggested that as the polarity increased, the fluorescence intensity of CDI decreased, and it was accompanied by a redshift of emission wavelength at the excitation wavelength of 524 nm, shifting from 641 nm to 721 nm. Significantly, CDI exhibited a notable ability to effectively target ER and enabled real-time monitoring of ER-phagy induced by starvation or drugs. Most importantly, alterations in polarity can be discerned through in vivo imaging in mice model of rheumatoid arthritis (RA). CDI has been proven effective in evaluating the therapeutic efficacy of drugs for RA. ER fluorescent probe CDI can be optically activated in lysosomes, providing a sensitive tool for studying ER-phagy in biology and diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Objective: Rheumatoid arthritis (RA) is an autoimmune disease in which the joint lining or synovium becomes highly inflamed and majorly contributes to disease progression. Understanding pathogenic processes in RA synovium is critical for identifying therapeutic targets. We performed laser capture microscopy (LCM) followed by RNA sequencing (LCM-RNAseq) to study regional transcriptomes throughout RA synovium., Methods: Synovial lining, sublining, and vessel samples were captured by LCM from seven patients with RA and seven patients with osteoarthritis (OA). RNAseq was performed on RNA extracted from captured tissue. Principal component analysis was performed on the sample set by disease state. Differential expression analysis was performed between disease states based on log 2 fold change and q value parameters. Pathway analysis was performed using the Reactome Pathway Database on differentially expressed genes among disease states. Significantly enriched pathways in each synovial region were selected based on the false discovery rate., Results: RA and OA transcriptomes were distinguishable by principal component analysis. Pairwise comparisons of synovial lining, sublining, and vessel samples between RA and OA revealed substantial differences in transcriptional patterns throughout the synovium. Hierarchical clustering of pathways based on significance revealed a pattern of association between biologic function and synovial topology. Analysis of pathways uniquely enriched in each region revealed distinct phenotypic abnormalities. As examples, RA lining samples were marked by anomalous immune cell signaling, RA sublining samples were marked by aberrant cell cycle, and RA vessel samples were marked by alterations in heme scavenging., Conclusion: LCM-RNAseq confirms reported transcriptional differences between the RA synovium and the OA synovium and provides evidence supporting a relationship between synovial topology and molecular anomalies in RA., (© 2024 American College of Rheumatology.)

Mesenchymal Stem Cells (MSCs) are of interest in the clinic because of their immunomodulation capabilities, capacity to act upstream of inflammation, and ability to sense metabolic environments. In standard physiologic conditions, they play a role in maintaining the homeostasis of tissues and organs; however, there is evidence that they can contribute to some autoimmune diseases. Gaining a deeper understanding of the factors that transition MSCs from their physiological function to a pathological role in their native environment, and elucidating mechanisms that reduce their therapeutic relevance in regenerative medicine, is essential. We conducted a Systematic Review and Meta-Analysis of human MSCs in preclinical studies of autoimmune disease, evaluating 60 studies that included 845 patient samples and 571 control samples. MSCs from any tissue source were included, and the study was limited to four autoimmune diseases: multiple sclerosis, rheumatoid arthritis, systemic sclerosis, and lupus. We developed a novel Risk of Bias tool to determine study quality for in vitro studies. Using the International Society for Cell & Gene Therapy's criteria to define an MSC, most studies reported no difference in morphology, adhesion, cell surface markers, or differentiation into bone, fat, or cartilage when comparing control and autoimmune MSCs. However, there were reported differences in proliferation. Additionally, 308 biomolecules were differentially expressed, and the abilities to migrate, invade, and form capillaries were decreased. The findings from this study could help to explain the pathogenic mechanisms of autoimmune disease and potentially lead to improved MSC-based therapeutic applications., Competing Interests: Declaration of Competing interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation and swelling. Several studies have demonstrated that RA fibroblast-like synovial cells (RA-FLS) play an important role in RA pathogenesis. Activated RA-FLS contribute to synovial inflammation by secreting inflammatory cytokines including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α. LMT-28 is derivative of oxazolidone and exerts anti-inflammatory effects on RA via IL-6 signaling pathway regulation. LMT-28 also regulates T cell differentiation in RA condition. However, the effect of LMT-28 on the migration and invasion of RA-FLS remains unknown. Kaempferol has been reported to have pharmacological effects on various diseases, such as inflammatory diseases, autoimmune diseases, and cancer. Additionally, kaempferol has been reported to inhibit RA-FLS migration and invasion, but it is not known about the therapeutic mechanism including molecular mechanism such as receptor. The present study aimed to investigate the synergistic effects of the combined treatment of LMT-28 and kaempferol on RA-FLS activation and RA pathogenesis in mouse model. LMT-28 and kaempferol co-administration inhibited RA disease severity and histological collapse in the joint tissues of CIA mice, as well as downregulated the levels of pro-inflammatory cytokines in mouse serum. Additionally, the combined treatment inhibited excessive differentiation of T helper 17 cells and osteoclasts. Furthermore, compared with single treatments, combined treatment showed enhanced inhibitory effects on the hyperactivation of IL-6-induced signaling pathway in RA-FLS. Combined treatment also inhibited RA-FLS cell proliferation, migration, and invasion and suppressed the expression of matrix metalloproteinase in RA-FLS. Furthermore, we confirmed that the combined treatment inhibited chondrocyte proliferation, migration, and invasion. In conclusion, our results suggest that the combined treatment of LMT-28 and kaempferol exerts a synergistic effect on the RA development via the regulation of IL-6-induced hyperactivation of RA-FLS. Furthermore, this study suggests that combination therapies can be an effective therapeutic option for arthritis., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Jeong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: This study aims to explore the effect of NONHSAT042241 on the function of rheumatoid arthritis -fibroblast-like synoviocyte (RA-FLS) and the underlying mechanisms., Methods: RA-FLS was treated with NONHSAT042241 overexpression and NONHSAT042241 knockdown lentiviruses. Cell counting kit-8 (CCK-8) assay, colony formation assay, flow cytometry, Transwell assay, western-blot, ELISA, and qRT-PCR were used to measure the changes of cell proliferation, apoptosis, invasion, secretion of inflammatory cytokines and matrix metalloproteinases (MMPs). Fluorescent in situ hybridization (FISH) assay, RNA pull-down assay, mass spectrometry (MS) and RNA immunoprecipitation (RIP) were used to find the target proteins that bond to NONHSAT042241, and western-blot was used to detect the expression of related proteins of Wnt/β-catenin signaling pathway., Results: Overexpression of NONHSAT042241 inhibited the proliferation of RA-FLS ( p  < 0.05), invasion, secretion of pro-inflammatory factors (IL-1and IL-6) and MMPs (MMP-1 and MMP-3) ( p  < 0.05), and elevated the level of pro-apoptotic factors (Bax and cleaved caspase3), while NONHSAT042241 knockdown had the opposite effect. NONHSAT042241 can directly bind to hnRNP D, and down-regulated the expression of β-catenin ( p  < 0.05), p-GSK-3β ( p  < 0.05), Cyclin D1 ( p  < 0.05), PCNA ( p  < 0.05), and thus reduced the cell proliferation., Conclusion: NONHSAT042241 may inhibit FLS-mediated rheumatoid synovial proliferation, inflammation and aggression. The underlying mechanisms may be that NONHSAT042241 inhibits the activity of Wnt/β-catenin signaling.

Ferroptosis is a form of iron-dependent regulated cell death caused by the accumulation of lipid peroxides. In this review, we summarize research on the impact of ferroptosis on disease models and isolated cells in various types of arthritis. While most studies have focused on rheumatoid arthritis (RA) and osteoarthritis (OA), there is limited research on spondylarthritis and crystal arthropathies. The effects of inducing or inhibiting ferroptosis on the disease strongly depend on the studied cell type. In the search for new therapeutic targets, inhibiting ferroptosis in chondrocytes might have promising effects for any type of arthritis. On the other hand, ferroptosis induction may also lead to a desired decrease of synovial fibroblasts in RA. Thus, ferroptosis research must consider the cell-type-specific effects on arthritis. Further investigation is needed to clarify these complexities.

Background: Ascorbic acid can regulate the function of the immune system. This study aimed to investigate the underlying mechanisms of ascorbic acid in plasma cell differentiation and rheumatoid arthritis (RA)., Methods: Mice were intraperitoneally injected with either ascorbic acid or an equivalent volume of phosphate-buffered saline (PBS). To elucidate the effects of ascorbic acid on arthritis, we utilized a collagen induced arthritis mouse model (CIA). To investigate the effects of ascorbic acid on antibody response, mice were immunized with (4-Hydroxy-3-nitrophenylacetyl)-Ficoll (NP-Ficoll) or (4-hydroxy-3-nitrophenyl) acetyl-keyhole limpet hemocyanin (NP-KLH) to elicit a T-cell independent (TI) or T-cell dependent (TD) antibody response. To clarify the ability of ascorbic acid on plasma cell production, we tracked the B cell differentiation fate on the NP-specific B1-8 hi BCR transgenic background., Results: Ascorbic acid-injected mice demonstrated significantly delayed disease incidence and decreased disease severity compared to PBS-injected mice. Ascorbic acid can reduce the titers of autoantibodies in both arthritis and lupus mice models. Ascorbic acid can significantly reduce the number of plasma cells and the production of antigen-specific antibodies in TI and TD antibody response. In addition, ascorbic acid can disrupt the antibody affinity maturation. Through B1-8 hi adoptive transfer experiments, it has been demonstrated that ascorbic acid restrains B cell differentiation into plasma cells in a cell-intrinsic manner. After in-depth exploration, we found that ascorbic acid can block the cell cycle of B cells and promote cell apoptosis. Mechanistically, ascorbic acid inhibited the production of autoreactive plasma cells by inhibiting the Stat3 signaling pathway., Conclusion: Our study demonstrates that ascorbic acid has the ability to suppress the generation of autoreactive plasma cells, diminish the production of autoantibodies, and consequently delay the onset of rheumatoid arthritis., (© 2024. The Author(s).)

The tumor necrosis factor receptor-associated factor 1 (TRAF1) plays a key role in promoting lymphocyte survival, proliferation, and cytokine production. Recent evidence showed that TRAF1 plays opposing roles in monocytes and macrophages where it controls NF-κB activation and limits pro-inflammatory cytokine production as well as inflammasome-dependent IL-1β secretion. Importantly, TRAF1 polymorphisms have been strongly linked to an increased risk of rheumatoid arthritis (RA). However, whether and how TRAF1 contributes to RA pathogenesis is not fully understood. Moreover, investigating the role of TRAF1 in driving RA pathogenesis is complicated by its multifaceted and opposing roles in various immune cells. In this study, we subjected wildtype (WT) mice to the collagen antibody-induced arthritis (CAIA) model of RA and injected them intra-articularly with WT- or TRAF1-deficient macrophages. We show that mice injected with TRAF1-deficient macrophages exhibited significantly exacerbated joint inflammation, immune cell infiltration, and tissue damage compared to mice injected with WT macrophages. This study may lay the groundwork for novel therapies for RA that target TRAF1 in macrophages.

It is not entirely clear how the interaction between joint inflammation and the central nervous system (CNS) response in rheumatoid arthritis (RA) works, and what pathophysiology underlies the sex differences in coexisting neuropsychiatric comorbidities. It is known that estrogen hormones reduce inflammation in RA and that this occurs mainly via the stimulation of G protein-coupled receptor-30 (GPR30), also known as G protein-coupled estrogen receptor (GPER) 1. However, changes in GPR30 expression and sex differences induced by local and systemic inflammation in RA are not yet known. Our aim was to reveal sex differences in the expression and association of joint GPR30 with local and systemic inflammation, clinical course and furthermore with hippocampal GPR30 expression during pristane-induced arthritis (PIA) in Dark Agouti (DA) rats, an animal model of RA. Furthermore, we demonstrated sex-specific differences in the association between joint and systemic inflammation and hippocampal microglia during PIA. Our results suggest sex-specific differences not only in the clinical course and serum levels of pro-inflammatory cytokines but also in the expression of GPR30. Female rats show greater synovial inflammation and greater damage to the articular cartilage compared to males during PIA attack. Male rats express higher levels of synovial and cartilaginous GPR30 than females during PIA, which correlates with a less severe clinical course. The correlation between synovial and cartilaginous GPR30 and joint inflammation scores (Krenn and Mankin) in male rats suggests that the more severe the joint inflammation, the higher the GPR30 expression. At the same time, there is no particular upregulation of hippocampal GPR30 in males. On the other hand, female rats express higher levels of neuroprotective GPR30 in the hippocampus than male rats at the basic level and during PIA attack. In addition, females have a higher number of Iba-1+ cells in the hippocampus during PIA attack that strongly correlates with the clinical score, serum levels of IL-17A, and Krenn and Mankin scores. These results suggest that male rats are better protected from inflammation in the joints and female rats are better protected from the inflammation in the hippocampus during a PIA attack, independently of microglia proliferation. However, in the remission phase, synovial GPR30 expression suddenly increases in female rats, as does hippocampal GPR30 expression in males. Further experiments with a longer remission period are needed to investigate the molecular background of these sex differences, as well as microglia phenotype profiling.

Ferroptosis is an iron-dependent mode of cell death distinct from apoptosis and necrosis. Its mechanisms mainly involve disordered iron metabolism, lipid peroxide deposition, and an imbalance of the antioxidant system. The endoplasmic reticulum is an organelle responsible for protein folding, lipid metabolism, and Ca 2+ regulation in cells. It can be induced to undergo endoplasmic reticulum stress in response to inflammation, oxidative stress, and hypoxia, thereby regulating intracellular environmental homeostasis through unfolded protein responses. It has been reported that ferroptosis and endoplasmic reticulum stress (ERS) have an interaction pathway and jointly regulate cell survival and death. Both have also been reported separately in rheumatoid arthritis (RA) mechanism studies. However, studies on the correlation between ferroptosis and ERS in RA have not been reported so far. Therefore, this paper reviews the current status of studies and the potential correlation between ferroptosis and ERS in RA, aiming to provide a research reference for developing treatments for RA., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ao, Hu and Huang.)

Anti-citrullinated protein autoantibodies (ACPA) are diagnostic for rheumatoid arthritis (RA). The antigens recognized by these autoantibodies are produced by protein arginine deiminases (PADs), particularly PAD4. However, it remains unknown why and how PAD4 causes this aberrant citrullination in RA. Here, we report that poly-perforin pores are present on freshly isolated neutrophils from RA patients, but not on healthy donor neutrophils. Neutrophils with perforin pores also contained intracellular citrullinated proteins in the region adjacent to the pores. This response was replicated in vitro by treating neutrophils with purified perforin, which generated intense dots of anti-perforin immunofluorescence, calcium influx, and intracellular citrullination. Extensive neutrophil killing in Felty's syndrome, an aggressive form of RA, correlated with particularly high ACPA, and PAD4 autoantibodies. In contrast, other forms of death, including NETosis, apoptosis, and pyroptosis, produced minimal citrullination. We conclude that neutrophil targeting by perforin leading to intracellular citrullination takes place in patients with RA., (© 2024. The Author(s).)

Angiogenesis is critical for rheumatoid arthritis (RA) progression. The effects of tofacitinib, a JAK-STAT inhibitor used for RA treatment, on angiogenesis in RA are unclear. We, therefore, evaluated the levels of angiogenic factors in two systems of a human co-culture of fibroblast (HT1080) and monocytic (U937) cell lines treated with tofacitinib and in serum samples from RA patients before and after six months of tofacitinib treatment. Tofacitinib reduced CD147 levels, matrix metalloproteinase-9 (MMP-9) activity, and angiogenic potential but increased endostatin levels and secreted proteasome 20S activity. In vitro, tofacitinib did not change CD147 mRNA but increased miR-146a-5p expression and reduced STAT3 phosphorylation. We recently showed that CD147 regulates the ability of MMP-9 and secreted proteasome 20S to cleave collagen XVIIIA into endostatin. We show here that tofacitinib-enhanced endostatin levels are mediated by CD147, as CD147-siRNA or an anti-CD147 antibody blocked proteasome 20S activity. The correlation between CD147 and different disease severity scores supported this role. Lastly, tofacitinib reduced endostatin' s degradation by inhibiting cathepsin S activity and recombinant cathepsin S reversed this in both systems. Thus, tofacitinib inhibits angiogenesis by reducing pro-angiogenic factors and enhancing the anti-angiogenic factor endostatin in a dual effect mediated partly through CD147 and partly through cathepsin S.

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease with complex pathogenesis. Single chemotherapy struggles to eliminate the disease permanently and reduce the pain owing to drug resistance and inadequate delivery to target cells. This study developed hyaluronic acid (HA)-modified and methotrexate (MTX)-load metal-organic frameworks (denoted as FT-HA-MTX NPs), combining photothermal therapy (PTT), photodynamic therapy (PDT), and chemotherapy to inhibit the progression of RA. In vitro experiments proved that the obtained NPs exhibited good biocompatibility and commendable photothermal conversion efficiency of 36.3 %. Additionally, they promoted ∙OH and O 2 production via the Fenton reaction, which dramatically alleviated hypoxia and enhanced ROS generation, and induced substantial mortality in activated RAW 264.7 cells, with cell viability of 31.72 %. Cellular uptake and in vivo imaging confirmed that the modification of HA enabled the NPs to specifically target activated macrophage, ensured prolonged retention of NPs in inflamed synovial tissues, and reduced systemic toxicity. In vivo, after FT-HA-MTX NPs treatment with laser irradiation, the levels of TNF-α and IL-1β in the synovial tissue were reduced by approximately 50 % compared to those in the inflamed synovium, demonstrating a significant enhancement in the anti-inflammatory effect (p < 0.001). In conclusion, FT-HA-MTX NPs are promising inflammation-targeted multifunctional nanoparticles that combine PTT, PDT, and chemotherapy, thereby significantly inhibiting the progression of RA while reducing systemic toxicity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Rationale: In inflammatory diseases such as rheumatoid arthritis (RA), steroid metabolism is a central component mediating the actions of immuno-modulatory glucocorticoids and sex steroids. However, the regulation and function of cellular steroid metabolism within key leukocyte populations such as macrophages remain poorly defined. In this study, the inflammatory regulation of global steroid metabolism was assessed in RA macrophages., Methods: Bulk RNA-seq data from RA synovial macrophages was used to assess transcripts encoding key enzymes in steroid metabolism and signalling. Changes in metabolism were assessed in synovial fluids, correlated to measures of disease activity and functionally validated in primary macrophage cultures., Results: RNA-seq revealed a unique pattern of differentially expressed genes, including changes in genes encoding the enzymes 11β-HSD1, SRD5A1, AKR1C2 and AKR1C3. These correlated with disease activity, favouring increased glucocorticoid and androgen levels. Synovial fluid 11β-HSD1 activity correlated with local inflammatory mediators (TNFα, IL-6, IL-17), whilst 11β-HSD1, SRD5A1 and AKR1C3 activity correlated with systemic measures of disease and patient pain (ESR, DAS28 ESR, global disease activity). Changes in enzyme activity were evident in inflammatory activated macrophages in vitro and revealed a novel androgen activating role for 11β-HSD1. Together, increased glucocorticoids and androgens were able to suppress inflammation in macrophages and fibroblast-like-synoviocytes., Conclusions: This study underscores the significant increase in androgen and glucocorticoid activation within inflammatory polarized macrophages of the synovium, contributing to local suppression of inflammation. The diminished profile of inactive steroid precursors in postmenopausal women may contribute to disturbances in this process, leading to increased disease incidence and severity., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

DNA origami is capable of spatially organizing molecules into sophisticated geometric patterns with nanometric precision. Here we describe a reconfigurable, two-dimensional DNA origami with geometrically patterned CD95 ligands that regulates immune cell signalling to alleviate rheumatoid arthritis. In response to pH changes, the device reversibly transforms from a closed to an open configuration, displaying a hexagonal pattern of CD95 ligands with ~10 nm intermolecular spacing, precisely mirroring the spatial arrangement of CD95 receptor clusters on the surface of immune cells. In a collagen-induced arthritis mouse model, DNA origami elicits robust and selective activation of CD95 death-inducing signalling in activated immune cells located in inflamed synovial tissues. Such localized immune tolerance ameliorates joint damage with no noticeable side effects. This device allows for the precise spatial control of cellular signalling, expanding our understanding of ligand-receptor interactions and is a promising platform for the development of pharmacological interventions targeting these interactions., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Intrinsically magnetic cells naturally occur within organisms and are believed to be linked to iron metabolism and certain cellular functions while the functional significance of this magnetism is largely unexplored. To better understand this property, an approach named Optical Tracking-based Magnetic Sensor (OTMS) has been developed. This multi-target tracking system is designed to measure the magnetic moment of individual cells. The OTMS generates a tunable magnetic field and induces movement in magnetic cells that are subsequently analyzed through a learning-based tracking-by-detection system. The magnetic moment of numerous cells can be calculated simultaneously, thereby providing a quantitative tool to assess cellular magnetic properties within populations. Upon deploying the OTMS, a stable population of magnetic cells in human peripheral monocytes is discovered. Further application in the analysis of clinical blood samples reveals an intriguing pattern: the proportion of magnetic monocytes differs significantly between systemic lupus erythematosus (SLE) patients and healthy volunteers. This variation is positively correlated with disease activity, a trend not observed in patients with rheumatoid arthritis (RA). The study, therefore, presents a new frontier in the investigation of the magnetic characteristics of naturally occurring magnetic cells, opening the door to potential diagnostic and therapeutic applications that leverage cellular magnetism., (© 2024 Wiley‐VCH GmbH.)

Rheumatoid arthritis (RA) is the most common chronic inflammatory disease, primarily affecting the joints and with stromal tissue dysregulation causing chronic inflammation and joint destruction. Rutin is a natural flavonoid with potential therapeutic properties in chronic destructive conditions including rheumatoid diseases. In this study, the protective effects of rutin nanoformulation in an animal model of rheumatoid arthritis caused by Freund's complete adjuvant (FCA) were investigated. Sixty male rats were randomly divided into ten groups including normal, negative control, prednisolone 10 mg/kg (positive control), 3 doses of rutin (15, 30, 45mg/kg), rutin nanoparticles (15, 30, 45 mg/kg), and nanoparticle without rutin, for 28 days. Different behavioral parameters including the open field test, acetone drop test, hot plate test, Von Frey test, and inclined plane test were evaluated. Serum levels of glutathione (GSH), catalase, and nitric oxide as well as histopathological analyses were measured in different groups. Also, matrix metalloproteinase (MMP)-2 and MMP-9 activity were appraised by gelatin zymography. The injection of FCA prolonged the rats' immobility duration in comparison to the control group. Rheumatoid arthritis induction also increased nitric oxide and decreased GSH and catalase levels, while these effects were reversed in the groups that received nanoparticles containing rutin and prednisolone. Rutin nanoparticles suppressed MMP-9 and activated MMP-2. Also, this rutin drug delivery system plays a significant role in the improvement of histopathological symptoms. Considering the improvement of behavioral and tissue symptoms and the modulation of the level of inflammatory cytokines, nanoparticles containing rutin can be proposed as a suitable approach in the management of patients with rheumatoid arthritis., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Rheumatoid arthritis is a chronic inflammatory disease that shows characteristic diurnal variation in symptom severity, where joint resident fibroblast-like synoviocytes (FLS) act as important mediators of arthritis pathology. We investigate the role of FLS circadian clock function in directing rhythmic joint inflammation in a murine model of inflammatory arthritis. We demonstrate FLS time-of-day-dependent gene expression is attenuated in arthritic joints, except for a subset of disease-modifying genes. The deletion of essential clock gene Bmal1 in FLS reduced susceptibility to collagen-induced arthritis but did not impact symptomatic severity in affected mice. Notably, FLS Bmal1 deletion resulted in loss of diurnal expression of disease-modulating genes across the joint, and elevated production of MMP3, a prognostic marker of joint damage in inflammatory arthritis. This work identifies the FLS circadian clock as an influential driver of daily oscillations in joint inflammation, and a potential regulator of destructive pathology in chronic inflammatory arthritis.

Objectives: The imbalance between apoptosis and proliferation in fibroblast-like synoviocytes (FLSs) plays a key role in the pathogenesis of rheumatoid arthritis (RA). This study aims to investigate the potential of all-trans retinoic acid (ATRA) as a supplementary therapeutic agent alongside methotrexate (MTX) for RA, by examining its ability to inhibit synovial cell proliferation and enhance apoptosis through the ROS-JNK signalling pathway., Methods: The viability, apoptosis, and autophagy levels of human rheumatoid arthritis fibroblast-like synovial cells (HFLS-RA) were evaluated, while ROS generation was measured through the DCFH-DA fluorescence microplate assay. Western blotting was used to analyse the expression levels of JNK signalling pathway-related proteins. To assess therapeutic potential in vivo, a collagen-induced arthritis (CIA) model was established in Wistar rats., Results: Small doses of MTX did not significantly affect the viability of HFLS-RAs or induce apoptosis. However, when ATRA was added to the treatment, the therapy markedly inhibited cell proliferation and induced apoptosis and excessive autophagy. Mechanistically, ATRA activated the ROS/JNK signalling pathway in HFLS-RAs. ROS scavengers and JNK inhibitors significantly attenuated ATRA-induced apoptosis and autophagy. In vivo, the combination therapy demonstrated a remarkable enhancement of the anti-arthritic efficacy in CIA rats., Conclusions: The ability of ATRA to inhibit proliferation in RA FLSs through autophagy and apoptosis underscores its potential as a supplementary therapeutic agent alongside MTX for RA, particularly when compared to the limited impact of MTX on these processes. This combined strategy holds promise for enhancing therapeutic outcomes and warrants further investigation in the management of RA.

Medicine intervention is the major clinical treatment used to relieve the symptoms and delay the progression of rheumatoid arthritis (RA), but is limited by its poor targeted delivery and short therapeutic duration. Herein, we developed an injectable and bioadhesive gelatin-based (Gel) hydrogel as a local depot of leonurine (Leon)-loaded and folate-functionalized polydopamine (FA-PDA@Leon) nanoparticles for anti-inflammation and chondroprotection in RA. The nanoparticles could protect Leon and facilitate its entry into the M1 phenotype macrophage for intracellular delivery of Leon, while the hydrogel tightly adhered to the tissues in the joint cavity and prolonged the retention of FA-PDA@Leon nanoparticles, thus achieving higher availability and therapeutic efficiency of Leon. In vitro and in vivo experiments demonstrated that the Gel/FA-PDA@Leon hydrogel could strongly suppress the inflammatory response by down-regulating the JAK2/STAT3 signaling pathway in macrophages and protect the chondrocytes from ferritinophagy/ferroptosis. This contributed to maintaining the structural integrity of articular cartilage and accelerating the joint functional recovery. This work provides an effective and convenient strategy to achieve higher bioavailability and long-lasting therapeutic duration of medicine intervention in arthritis diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Rheumatoid arthritis (RA) is the predominant manifestation of inflammatory arthritis, distinguished by an increasing burden of morbidity and mortality. The intricate interplay of genes and signalling pathways involved in synovial inflammation in patients with RA remains inadequately comprehended. This study aimed to ascertain the role of necroptosis in RA, as along with their associations with immune cell infiltration. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were employed to identify central genes for RA. In this study, identified total of 28 differentially expressed genes (DEGs) were identified in RA. Utilising WGCNA, two co-expression modules were generated, with one module demonstrating the strongest correlation with RA. Through the integration of differential gene expression analysis, a total of 5 intersecting genes were discovered. These 5 hub genes, namely fused in sarcoma (FUS), transformer 2 beta homolog (TRA2B), eukaryotic translation elongation factor 2 (EEF2), cleavage and polyadenylation specific factor 6 (CPSF6) and signal transducer and activator of transcription 3 (STAT3) were found to possess significant diagnostic value as determined by receiver operating characteristic (ROC) curve analysis. The close association between the concentrations of various immune cells is anticipated to contribute to the diagnosis and treatment of RA. Furthermore, the infiltration of immune cells mentioned earlier is likely to exert a substantial influence on the initiation of this disease.

It is crucial to identify aberrant HClO levels in living things since they pose a major health risk and are a frequent reactive oxygen species (ROS) in living organisms. In order to detect HClO in various biological systems, we created and synthesized a near-infrared fluorescent probe with an oxime group (-C = N-OH) as a recognition unit. The probe DCMP1 has the advantages of fast response (10 min), near-infrared emission (660 nm), large Stokes shift (170 nm) and high selectivity. This probe DCMP1 not only detects endogenous HClO in living cells, but also enables further fluorescence detection of HClO in living zebrafish. More importantly, it can also be used for fluorescence imaging of HClO in an rheumatoid arthritis mouse model. This fluorescent probe DCMP1 is anticipated to be an effective tool for researching HClO., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Objectives: To compare disease activity as assessed by ultrasonography (US) between rheumatoid arthritis (RA) patients with and without anxiety or depression, and to compare clinical disease activity and sociodemographic measures between these patient groups., Methods: Anxious or depressed patients were identified by EuroQoL-5D-3L question "I am not/moderately/extremely anxious or depressed." US assessments of 36 joints and 4 tendons were performed and power Doppler (PD) and grey scale (GS) sum scores calculated (both range 0-120). Comparisons between anxious/depressed and not anxious/depressed patients were performed in unadjusted analyses, adjusted logistic regression, and sensitivity analyses., Results: A total of 201 RA patients starting biological disease-modifying antirheumatic drugs were included (82 % women, mean age 52 years, disease duration 10 years). Hundred-and-nine patients (54.2 %) were moderately or extremely anxious/depressed. Median (IQR) PD (13 (4, 21) vs. 10 (3, 20), p = 0.53) and GS (28 (18, 42) vs. 25 (14, 41), p = 0.51) sum scores were similar between anxious/depressed and not anxious/depressed patients, respectively, whereas composite scores of disease activity were significantly worse in the anxious/depressed patients (p < 0.001), as were also patient-reported outcomes, ESR, CRP and plasma calprotectin (all p ≤ 0.02). Sensitivity analyses confirmed these findings, except for CRP. Self-reported economy and sleep difficulties were also worse in the anxious/depressed patients and a higher proportion were not working (all p < 0.001)., Conclusion: This study highlights the negative impact of anxiety and depression on RA patients in standard care, and underscores the challenges in disease activity assessment. US examination may be a valuable objective tool in the evaluation of these patients., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Brigitte Michelsen reports financial support was provided by South-Eastern Norway Regional Health Authority. Diakonhjemmet Hospital reports financial support was provided by Research Council of Norway. Brigitte Michelsen reports a relationship with Novartis AG that includes: funding grants and speaking and lecture fees. Tore K Kvien reports a relationship with Grünenthal Ltd that includes: speaking and lecture fees. Tore K Kvien reports a relationship with Janssen Pharmaceuticals Inc that includes: consulting or advisory and speaking and lecture fees. Tore K Kvien reports a relationship with Sandoz Inc that includes: consulting or advisory and speaking and lecture fees. Tore K Kvien reports a relationship with AbbVie Inc that includes: consulting or advisory and funding grants. Tore K Kvien reports a relationship with Gilead Sciences that includes: consulting or advisory. Tore K Kvien reports a relationship with Novartis that includes: consulting or advisory and funding grants. Tore K Kvien reports a relationship with Pfizer that includes: consulting or advisory and funding grants. Tore K Kvien reports a relationship with UCB that includes: consulting or advisory and funding grants. Sella Aarestad Provan reports a relationship with Pfizer and Boehringer Ingelheim that includes: consulting or advisory. Hilde Berner Hammer reports a relationship with AbbVie that includes: consulting or advisory and speaking and lecture fees. Hilde Berner Hammer reports a relationship with Novartis that includes: consulting or advisory and speaking and lecture fees. Hilde Berner Hammer reports a relationship with UCB that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Fibroblast-like synoviocytes (FLS) plays an important role in synovial inflammation and joint damage in rheumatoid arthritis (RA). As the most abundant mRNA modification, N6-methyladenosine (m 6 A) is involved in the development of various diseases; however, its role in RA remains to be defined. In this study, we reported the elevated expression of the m 6 A demethylase fat mass and obesity-associated protein (FTO) in FLS and synovium from RA patients. Functionally, FTO knockdown or treatment with FB23-2, an inhibitor of the mRNA m 6 A demethylase FTO, inhibited the migration, invasion and inflammatory response of RA FLS, however, FTO-overexpressed RA FLS exhibited increased migration, invasion and inflammatory response. We further demonstrated that FTO promoted ADAMTS15 mRNA stability in an m 6 A-IGF2BP1 dependent manner. Notably, the severity of arthritis was significantly reduced in CIA mice with FB23-2 administration or CIA rats with intra-articular injection of FTO shRNA. Our results illustrate the contribution of FTO-mediated m 6 A modification to joint damage and inflammation in RA and suggest that FTO might be a potential therapeutic target in RA., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The molecular signature of cell-derived extracellular vesicles (EVs) from synovial fluid (SF) offers insights into the cells and molecular processes associated with joint disorders and can be exploited to define biomarkers. The EV-signature is determined by cargo molecules and the lesser-studied lipid bilayer. We here investigated the lipidome of SF-EVs in inflamed joints derived from Rheumatoid Arthritis (RA) and Spondyloarthritis (SpA) patients, two autoimmune-driven joint diseases, and compared these signatures to the lipid profile of equine SF-EVs obtained during induced acute synovitis. Since neutrophils are primary SF-infiltrating cells during these inflammatory joint diseases, we also analyzed how inflammatory stimuli alter the lipidomic profile of human and equine neutrophil-derived EVs (nEVs) in vitro and how these signatures relate to the lipidome signatures of SF-EVs from inflamed joints. We identified neutrophil stimulation intensity-dependent changes in the lipidomic profile of nEVs with elevated presence of dihexosylceramide (lactosylceramide), phosphatidylserine, and phosphatidylethanolamine ether-linked lipid classes in human nEVs upon full neutrophil activation. In horses, levels of monohexosylceramide (glucosylceramide) increased instead of dihexosylceramide, indicating species-specific differences. The lipid profiles of RA and SpA SF-EVs were relatively similar and showed a relative resemblance with stimulated human nEVs. Similarly, the lipidome of equine synovitis-derived SF-EVs closer resembled the one of stimulated equine nEVs. Hence, lipidome profiling can provide insights into the contribution of nEVs to the heterogeneous pool of SF-EVs, deepening our understanding of inflammatory joint diseases and revealing molecular changes in joint homeostasis, which can lead to the development of more precise disease diagnosis and treatment strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Epstein-Barr virus (EBV) and other viral infections are possible triggers of autoimmune diseases, such as rheumatoid arthritis (RA). To analyze the causative relationship between EBV infections and RA development, we performed experiment on humanized NOD/Shi-scid/IL-2RγC null (hu-NOG) mice reconstituted human immune system components and infected with EBV. In EBV-infected hu-NOG mice, breakdown of knee joint bones was found to be accompanied by the accumulation of receptor activator of nuclear factor-κB (NF-κB) (RANK) ligand (RANKL), a key factor in osteoclastogenesis, human CD19 and EBV-encoded small RNA (EBER)-bearing cells. Accumulation of these cells expanded in the bone marrow adjacent to the bone breakage, showing a histological feature like to that in bone marrow edema. On the other hand, human RANK/human matrix metalloprotease-9 (MMP-9) positive, osteoclast-like cells were found at broken bone portion of EBV-infected mouse knee joint. In addition, human macrophage-colony stimulating factor (M-CSF), an essential factor in development of osteoclasts, evidently expressed in spleen and bone marrow of EBV-infected humanized mice. Furthermore, RANKL and M-CSF were identified at certain period of EBV-transformed B lymphoblastoid cells (BLBCs) derived from umbilical cord blood lymphocytes. Co-culturing bone marrow cells of hu-NOG mice with EBV-transformed BLBCs resulted in the induction of a multinucleated cell population positive for tartrate-resistant acid phosphatase and human MMP-9 which indicating human osteoclast-like cells. These findings suggest that EBV-infected BLBCs induce human aberrant osteoclastogenesis, which cause erosive arthritis in the joints., Competing Interests: Declaration of competing interest All of authors do not have any financial and personal relationships with other people or organizations that could inappropriately influence our/their work., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)