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Ethnopharmacological Relevance: As a traditional Chinese medicine, the flower of Rhododendron molle G. Don (RMF) is record in the Chinese pharmacopoeia, and is commonly utilized for treating rheumatoid arthritis (RA) in clinical practice. However, its precise mechanisms necessitate further exploration., Aim of the Study: To expound the effective components, targets, metabolites, and pathways participated in RMF's anti-RA effects by metabolomics integrated network pharmacology., Materials and Methods: CIA rats were intragastric administered RMF for 2 weeks, following which the therapeutic effects were comprehensively evaluated. Serum metabolomics was adopted to investigate the differential metabolites (DEMs). UHPLC-Q-Exactive-MS method was applied to identify the components of RMF, and then network pharmacology was utilize to select the component-RA-targets. Molecular docking and Western blotting were utilized to validate the key targets., Results: RA symptoms were alleviated by RMF through the inhibition secretion of pro-inflammatory factors IL-1β, IL-6 and TNF-α, along with relief in bone destruction observed in CIA rats. Four targets, namely AKR1B1, TPH1, CYP1A1, and CYP1A2, were identified, along with their corresponding metabolites, namely D-glucose, D-mannose, L-tryptophan, 11-deoxycorticosterone, and 17α-hydroxyprogesterone. These were found to be involved in three key metabolic pathways: steroid hormone biosynthesis, tryptophan metabolism, and galactose metabolism. Additionally, five significant anti-RA active components were identified from RMF, including Rhodojaponin (Rj)-Ⅱ, Rj-Ⅲ, Rj-Ⅴ, Rj-Ⅵ, and quercetin., Conclusions: The anti-RA mechanisms of RMF were investigated in this study, focusing on active components, upstream targets, and downstream metabolites. These findings lay a foundation for the clinical practice and drug development of RMF., 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.)

Ethnopharmacological Relevance: Wutou Decoction (WTD) is a classic traditional Chinese medicine formula, which has shown clinical efficacy in treating rheumatoid arthritis (RA). The Treg stability and Th17/Treg imbalance is an important immunological mechanism in RA progression. Whether WTD regulates CD4 + T cell subsets has not been thoroughly investigated yet., Aim of the Study: This study aimed to explore the potential role and mechanisms of WTD in regulating the diminished stability of Treg cells and the imbalance of CD4 + T cell subsets via in vivo and in vitro experiments., Materials and Methods: Firstly, the therapeutic effects of WTD on the collagen-induced arthritis (CIA) mouse and its potential regulatory function on CD4 + T cell subsets were evaluated in vivo. Animal specimens were collected after 31 days of treatment with WTD. The anti-arthritic and anti-inflammatory effects of WTD were assessed through arthritis scoring, body weight, spleen index, serum IL-6 levels, and micro-PET/CT imaging. Gene enrichment analysis was performed to evaluate the activation T cell-related signaling pathway. Flow cytometry was used to determine the proportions of CD4 + T cell subsets in vitro and in vitro. Additionally, ELISA was used to assess the secretion of IL-10 and TGF-β by Treg cells under inflammatory conditions. The suppressive function of Treg cells on cell proliferation under inflammatory conditions was examined using CFSE labeling. Immunofluorescence staining was performed to detect the phosphorylation levels of STAT3 in CD4 + T cells from mouse spleen tissues. Western blotting was used to evaluate the phosphorylation levels of JAK2/STAT3 in Treg cells., Results: WTD significantly alleviated joint inflammation in CIA mice. WTD reduced serum IL-6 levels in CIA mice, improved their body weight and spleen index. WTD treatment inhibited the activation of CD4 + T cell subgroup-related signaling in the joint tissues of CIA mice. In vitro and in vitro experiments showed that WTD increased the proportion of Treg cells and decreased the proportion of Th17 cells in CIA mice spleen. Furthermore, WTD promoted the secretion of IL-10 and TGF-β by Treg cells and enhanced the inhibitory capacity of Treg cells on cell proliferation under inflammatory conditions. Immunofluorescence detected decreased STAT3 phosphorylation levels in CD4 + T cells from CIA mice spleen, while western blotting revealed a decrease in JAK2/STAT3 phosphorylation levels in Treg cells in vitro., Conclusions: Inhibiting JAK2/STAT3 phosphorylation is a potential mechanism through which WTD improves Treg cell stability, balances CD4 + T cell subsets, and attenuates RA joint inflammation., Competing Interests: Declaration of competing interest The authors have no conflicts of interest in this study., (Copyright © 2024. Published by Elsevier B.V.)

Tripterygium wilfordii Hook. f. is a traditional Chinese herb that is used to treat rheumatoid arthritis (RA). Triptolide (TP), an epoxidized diterpene lactone extracted from this herb, has been suggested to be the primary active and toxic component. In this work, the material basis and molecular mechanism of toxicity induced by T. wilfordii preparations in RA were investigated. Female rats with collagen-induced arthritis were given 500 μg·kg -1 TP intragastrically or intravenously. Compared with that in the control group, the AUC last in the CIA group was 1.7-fold greater after intragastric administration, while this value decreased 22.6 % after intravenous administration, suggesting that the absorption of TP was significantly greater in the CIA group. The results from RT-PCR and probe substrate perfusion indicated that Oatp1a5 expression was upregulated while P-glycoprotein (P-gp) expression was downregulated in the duodenums of CIA rats. Naringin, an inhibitor of Oatp1a5, decreased the P eff of TP in the rat duodenum by 27.9 %, whereas verapamil hydrochloride, an inhibitor of P-gp, increased the P eff by 50.8 %, suggesting that Oatp1a5 and P-gp mediate the uptake and efflux of TP in the rat duodenum, respectively. Furthermore, among the upstream nuclear receptors, the mRNA expression levels and protein expression levels of FXR and VDR were noticeably decreased. In the present study, the absorption of TP in the duodenums of CIA rats significantly increased due to the upregulation of Oatp1a5 expression and the downregulation of P-gp expression, leading to an increase in TP plasma exposure after intragastric administration. The altered expression of Oatp1a5 and P-gp may be related to FXR and VDR., 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.)

Ethnopharmacological Relevance: Traditional Chinese herbal medicine Panax japonicus C.A. Meyer has a long history in clinical treatment of rheumatoid arthritis (RA). Total saponins of Panax japonicus C.A. Meyer (TSPJs) were extracted from the root of Panax japonicus C.A. Meyer, and its anti-rheumatism mechanism is still unclear., Aim of the Study: To investigate whether TSPJs attenuated synovial angiogenesis in RA and explore the potential mechanisms., Materials and Methods: Potential TSPJs targets involving gene function were predicted by network pharmacology related databases. Bioinformatics analysis and molecular docking technology were used to predict the mechanism of TSPJs in the treatment of RA. The predicted results were validated by cell experiments and a collagen-induced arthritis (CIA) mouse model., Results: Bioinformatics analysis results showed that TSPJs may inhibit RA-related angiogenesis through the hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) pathways. In vitro, different doses of TSPJs showed a good inhibitory effect on the tube formation of EA.hy926 cells. The results of the cellular thermal shift assay indicated that TSPJs can bind to the HIF-1α, VEGFA, and angiopoietin-1 (ANG-1) proteins. In vivo, the administration of TSPJs alleviated the symptoms of CIA mice, including the arthritis index, hind paw thickness, and swollen joint count. The histological results demonstrated that TSPJs inhibited inflammation, angiogenesis, bone damage, and cartilage destruction. Furthermore, TSPJs decreased the number of vessels and the expression level of CD31. The mechanistic results revealed that TSPJs decreased the expression of HIF-1α, VEGFA, and ANG-1 in the serum or synovial tissues of CIA mice., Conclusion: These results suggest that TSPJs effectively inhibit angiogenesis in RA, and the mechanism may be related to inhibiting the HIF-1α/VEGF/ANG-1 axis., 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.)

Rheumatoid arthritis causes excessive bone loss by stimulating osteoclast differentiation. Extracellular vesicles are valuable disease markers, conveyors of distant cell-to-cell communication, and carriers for drug delivery. The aim of this study was to investigate the anti-osteoclastogenic effects of extracellular vesicles derived from dairy Propionibacterium freudenreichii MJ2 (PFEVs) and the improvement effect of PFEVs on collagen-induced arthritis (CIA) animal model. PFEVs were observed by scanning electron microscopy, transmission electron microscopy, nanoparticle tracking analysis, and LC-MS/MS. The inhibitory activity of PFEVs against receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast differentiation was investigated in RAW 264.7 cells. PFEVs significantly decreased the expression levels of genes and proteins related to osteoclast differentiation. PFEVs decreased RANK-RANKL binding. In a CIA mouse model, PFEVs treatment significantly reduced arthritis scores and collagen-specific immunoglobulins. PFEVs treatment also reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines. The anti-inflammatory effects were confirmed by H&E staining, and PFEVs treatment inhibited osteoclastogenesis in the CIA mouse model. In conclusion, PFEVs inhibited osteoclast differentiation by inhibiting RANK-RANKL signaling, thereby decreasing the expression of osteoclast differentiation-related genes. PFEVs also improved collagen-induced arthritis by inhibiting inflammation and osteoclastogenesis., (© 2024. The Author(s).)

Rheumatoid arthritis (RA) is marked by joint damage and inflammation, with B cells playing a key role by generating autoantibodies. This study shows that G protein-coupled receptor 40 (GPR40) deficiency in B cells leads to increased activation, proliferation, antibody production, germinal center formation, and class switch recombination. GPR40 regulates Plcγ2 phosphorylation and intracellular calcium flux downstream of the B cell receptor by binding to the Gαq protein. In GPR40-deficient mice, susceptibility to collagen-induced arthritis was higher. GPR40 agonists showed potential as therapeutic agents, and their reduced expression in patients with RA correlated with disease onset, suggesting GPR40 as a potential therapeutic target and diagnostic marker., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

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

Background: Marine diterpenes represent a promising reservoir for identifying potential anti-rheumatoid arthritis (RA) candidates. Praelolide is a gorgonian-derived briarane-type diterpenoid with antioxidative and anti-osteoclastogenetic properties., Objective: This study aims to evaluate the therapeutic efficacy of praelolide against RA and investigate its underlying mechanisms both in vivo and in vitro., Method: Collagen-induced arthritis (CIA) mice and human RA fibroblast-like synoviocyte MH7A cells were employed for bioassays. The VisuGait system was utilized to assess gait dysfunction resulting from joint pain. Histopathological changes in ankle and synovial tissues were evaluated using micro-computed tomography, hematoxylin and eosin staining, Safranin-O/Fast Green staining, tartrate resistant acid phosphatase staining, and immunohistochemistry. Fluorescence spectroscopy, circular dichroism, and surface plasmon resonance were employed to investigate interactions between praelolide and catalase. The production of inflammatory cytokines and expression levels of proteins were assessed using ELISA and Western blotting, respectively., Result: Praelolide significantly reduced paw swelling and arthritis scores, improved gait deficits, and restored synovial histopathological alterations and bone erosion in CIA mice. In vivo and in vitro, praelolide effectively decreased the expression and production of inflammatory cytokines such as interleukin (IL)-1β and IL-6. Additionally, praelolide inhibited osteoclastogenesis on bone surface of the ankle joints and in a tumor necrosis factor-α (TNF-α)-induced MH7A/bone marrow-derived macrophages (BMMs) co-culture system, and it strongly suppressed reactive oxygen species (ROS) production. Mechanistically, praelolide modulated catalase through non-covalent interactions, inducing conformational alterations that enhanced catalase activity and stability against time- and temperature-induced degradation. Further investigation revealed that praelolide significantly upregulated the expression of Nrf2, subsequently activating downstream antioxidant enzymes., Conclusion: Praelolide markedly alleviated synovial inflammation and bone destruction in CIA mice by enhancing catalase activity and activating the Nrf2 pathway to reduce disease-related ROS accumulation, highlighting praelolide as a promising candidate for multitarget treatment of RA., Competing Interests: Declaration of competing interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with this manuscript submitted., (Copyright © 2024. Published by Elsevier GmbH.)

It has been reported that the symptoms of rheumatoid arthritis (RA) can be ameliorated by acupuncture, an external treatment of traditional Chinese medicine. However, the immune mechanism underlying its action is elusive. Accordingly, this study investigated the role and mechanism of manual acupuncture (MA) in collagen-induced arthritis (CIA) in mice. The results demonstrated that MA or NaB treatment reduced Articular Index scores and right paw thickness and alleviated synovial inflammation and cartilage damage. MA or NaB treatment altered the content and relative abundance of short-chain fatty acids, particularly butyric and propionic acids, in feces. Additionally, MA or NaB treatment elevated SCD1, SREBP1, and GPX4 protein expression in synovial tissues and GSH-px contents in serum while decreasing ROS fluorescence intensity and MDA contents in peripheral blood. A linear correlation was found between the relative expression of SCD1 and SREBP1 in synovial tissues and the contents of propionic acids and butyric acids in feces, as well as between the contents of propionic acids and butyric acids. In summary, MA regulates butyric acids to inhibit ferroptosis, therefore suppressing inflammation in RA., 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.)

Rheumatoid arthritis (RA) is an autoimmune disease featured by chronic synovitis and progressive joint damage. Early treatment before the onset of clinical symptoms (also known as the pre-RA stage) may slow or stop the progression of the disease. We sought to discover the dynamic metabolic changes during the evolution of collagen-induced arthritis (CIA) to better characterize the disease stages. Untargeted metabolomics analysis using gas chromatography-mass spectrometry revealed that the metabolic profiles of CIA mice gradually differed from that of the control group with the progression of the disease. During the induction phase, the CIA group showed some metabolic alterations in galactose metabolism, arginine biosynthesis, tricarboxylic acid cycle (TCA cycle), pyruvate metabolism, and starch/sucrose metabolism. During the early inflammatory phase, no joint swelling was observed in CIA mice, and metabolites changed mainly involving amino acid metabolism (arginine biosynthesis, arginine/proline metabolism, phenylalanine/tyrosine/tryptophan biosynthesis), and glutathione metabolism. During the peak inflammatory phase, severe arthritis symptoms were observed in CIA mice, and there were more extensive metabolic alterations in valine/leucine/isoleucine biosynthesis, phenylalanine/tyrosine/tryptophan biosynthesis, TCA cycle, galactose metabolism, and arginine biosynthesis. Moreover, the reduction of specific amino acids, such as glycine, serine, and proline, during the early stages may result in an imbalance in macrophage polarization and enhance the inflammatory response in CIA mice. Our study confirmed that specific perturbations in amino acid metabolism have occurred in CIA mice prior to the onset of joint symptoms, which may be related to autoimmune disorders. The findings could provide insights into the metabolic mechanism and the diagnosis of pre-RA., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Conflicting data exist in rheumatoid arthritis and the collagen-induced arthritis (CIA) murine model of autoimmune arthritis regarding the role of bacterial carnitine and choline metabolism into the inflammatory product trimethylamine (TMA), which is oxidized in the liver to trimethylamine-N-oxide (TMAO). Using two published inhibitors of bacterial TMA lyase, 3,3-dimethyl-1-butanol (DMB) and fluoromethylcholine (FMC), we tested if TMA/TMAO were relevant to inflammation in the development of CIA. Surprisingly, DMB-treated mice demonstrated > 50% reduction in arthritis severity compared to FMC and vehicle-treated mice, but amelioration of disease was independent of TMA/TMAO production. Given the apparent contradiction that DMB did not inhibit TMA, we then investigated the mechanism of protection by DMB. After verifying that DMB acted independently of the intestinal microbiome, we traced the metabolism of DMB within the host and identified a novel host-derived metabolite of DMB, 3,3-dimethyl-1-butyric acid (DMBut). In vivo studies of mice treated with DMB or DMBut demonstrated efficacy of both molecules in significantly reducing disease and proinflammatory cytokines in CIA, while in vitro studies suggest these molecules may act by modulating secretion of proinflammatory cytokines from macrophages. Altogether, our study suggests that DMB and/or its metabolites are protective in CIA through direct immunomodulatory effects rather than inhibition of bacterial TMA lyases., (© 2024. The Author(s).)

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.)

Rheumatoid arthritis (RA) is considered a multifactorial condition where interaction between the genetic and environmental factors lead to immune dysregulation causing autoreactivity. While among the various genetic factors, HLA-DR4 and DQ8, have been reported to be the strongest risk factors, the role of various environmental factors has been unclear. Though events initiating autoreactivity remain unknown, a mucosal origin of RA has gained attention based on the recent observations with the gut dysbiosis in patients. However, causality of gut dysbiosis has been difficult to prove in humans. Mouse models, especially mice expressing RA-susceptible and -resistant HLA class II genes have helped unravel the complex interactions between genetic factors and gut microbiome. This review describes the interactions between HLA genes and gut dysbiosis in sex-biased preclinical autoreactivity and discusses the potential use of endogenous commensals as indicators of treatment efficacy as well as therapeutic tool to suppress pro-inflammatory response in rheumatoid arthritis., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Rheumatoid arthritis (RA) seriously affects the daily life of people. The whole plant of Artemisia ordosica Krasch. (AOK) has been used in folk medicine. This study aimed to investigate the in vivo anti-RA effects of AOK extract (AOKE) on collagen-induced arthritis in rats., Methods: AOKE (400, 200, or 100 mg/kg) was administered orally to animals for 30 days. Body weight, paw swelling, arthritis index, thymus, and spleen indices, and pathological changes were assessed for effects of AOKE on RA. Furthermore, the inflammatory cytokines in rat serum were detected. In addition, the expressions of STAT3, Caspase-3, Galectin-3, and S100A9 in synovial tissue were researched using immunohistochemistry., Key Findings: The AOKE significantly reduced the arthritis indices, paw swelling, spleen, and thymus indices. Meanwhile, AOKE (400 mg/kg) decreased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-17A, and increased the level of IL-10 in rat serum. Histopathological examination showed that AOKE reduced inflammatory cell infiltration and cartilage erosion. Then, AOKE decreased the expressions of STAT3, Galectin-3, S100A9, and increased the expression of Caspase-3., Conclusion: AOKE had interesting anti-RA activity in rats, which deserved further research for the development and clinical use of this medicinal resource., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Fu-zi decoction (FZD) has a long history of application for treating Rheumatoid arthritis (RA) as a classic formulation. However, its underlying mechanisms have not been fully elucidated. This study aimed to decipher the potential mechanism of FZD in treating RA, with a specific focus on receptor activator of nuclear factor κB/receptor activator of nuclear factor κB ligand (RANK/RANKL) signaling pathway., Methods: The impact of FZD on RA was investigated in collagen-induced arthritis rats (CIA), and the underlying mechanism was investigated in an osteoclast differentiation cell model. In vivo , the antiarthritic effect of FZD at various doses (2.3, 4.6, 9.2 g/kg/day) was evaluated by arthritis index score, paw volume, toe thickness and histopathological examination of inflamed joints. Additionally, the ankle joint tissues were determined with micro-CT and safranin O fast green staining to evaluate synovial hyperplasia and articular cartilage damage. In vitro , osteoclast differentiation and maturation were evaluated by TRAP staining in RANKL-induced bone marrow mononuclear cells. The levels of pro- and anti-inflammatory cytokines as well as RANKL and OPG were evaluated by ELISA kits. In addition, Western blotting was used to investigate the effect of FZD on RANK/RANKL pathway activation both in vivo and in vitro ., Results: FZD significantly diminished the arthritis index score, paw volume, toe thickness and weigh loss in CIA rats, alleviated the pathological joint alterations. Consistent with in vivo results, FZD markedly inhibited RANKL-induced osteoclast differentiation by decreasing osteoclast numbers in a dose-dependent manner. Moreover, FZD decreased the levels of pro-inflammatory cytokines IL-6, IL-1β and TNF-α, while increasing anti-inflammatory cytokine IL-10 level both in serum and culture supernatants. Treatment with FZD significantly reduced serum RANKL levels, increased OPG levels, and decreased the RANKL/OPG ratio. In both in vivo and in vitro settings, FZD downregulated the protein expressions of RANK, RANKL, and c-Fos, while elevating OPG levels, further decreasing the RANKL/OPG ratio., Conclusion: In conclusion, FZD exerts a therapeutic effect in CIA rats by inhibiting RANK/RANKL-mediated osteoclast differentiation, which suggested that FZD is a promising treatment 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 Pan, Li, Xu, Ye, Liu, Wang, Deng, Song, Mei and Li.)

Rheumatoid arthritis (RA) is a chronic autoimmune disease marked by synovitis and cartilage destruction. The active compound, icariin (ICA), derived from the herb Epimedium, exhibits potent anti-inflammatory properties. However, its clinical utility is limited by its water insolubility, poor permeability, and low bioavailability. To address these challenges, we developed a multifunctional drug delivery system-adipose-derived stem cells-exosomes (ADSCs-EXO)-ICA to target active macrophages in synovial tissue and modulate macrophage polarization from M1 to M2. High-performance liquid chromatography analysis confirmed a 92.4 ± 0.008% loading efficiency for ADSCs-EXO-ICA. In vitro studies utilizing cellular immunofluorescence (IF) and flow cytometry demonstrated significant inhibition of M1 macrophage proliferation by ADSCs-EXO-ICA. Enzyme-linked immunosorbent assay, cellular transcriptomics, and real-time quantitative PCR indicated that ADSCs-EXO-ICA promotes an M1-to-M2 phenotypic transition by reducing glycolysis through the inhibition of the ERK/HIF-1α/GLUT1 pathway. In vivo, ADSCs-EXO-ICA effectively accumulated in the joints. Pharmacodynamic assessments revealed that ADSCs-EXO-ICA decreased cytokine levels and mitigated arthritis symptoms in collagen-induced arthritis (CIA) rats. Histological analysis and micro computed tomography confirmed that ADSCs-EXO-ICA markedly ameliorated synovitis and preserved cartilage. Further in vivo studies indicated that ADSCs-EXO-ICA suppresses arthritis by promoting an M1-to-M2 switch and suppressing glycolysis. Western blotting supported the therapeutic efficacy of ADSCs-EXO-ICA in RA, confirming its role in modulating macrophage function through energy metabolism regulation. Thus, this study not only introduces a drug delivery system that significantly enhances the anti-RA efficacy of ADSCs-EXO-ICA but also elucidates its mechanism of action in macrophage function inhibition., (© 2024. The Author(s).)

The discovery of alternative medicines with fewer adverse effects is urgently needed for rheumatoid arthritis (RA). Sophoridine (SR), the naturally occurring quinolizidine alkaloid isolated from the leguminous sophora species, has been demonstrated to possess a wide range of pharmacological activities. However, the effect of SR on RA remains unknown. In this study, the collagen-induced arthritis (CIA) rat model and tumor necrosis factor alpha (TNFα)-induced fibroblast-like synoviocytes (FLSs) were utilized to investigate the inhibitory effect of SR on RA. The anti-arthritic effect of SR was evaluated using the CIA rat model in vivo and TNFα-stimulated FLSs in vitro. Mechanistically, potential therapeutic targets and pathways of SR in RA were analyzed through drug target databases and disease databases, and validation was carried out through immunofluorescence, immunohistochemistry, and Western blot. The in vivo results revealed that SR treatment effectively ameliorated synovial inflammation and bone erosion in rats with CIA. The in vitro studies showed that SR could significantly suppress the proliferation and migration in TNFα-induced arthritic FLSs. Mechanistically, SR treatment efficiently inhibited the activation of MAPKs (JNK and p38) and NF-κB pathways in TNFα-induced arthritic FLSs. These findings were further substantiated by Immunohistochemistry results in the CIA rat. SR exerts an anti-arthritic effect in CIA rats through inhibition of the pathogenic characteristic of arthritic FLSs via suppressing NF-κB and MAPKs (JNK and p38) signaling pathways. SR may have a great potential for development as a novel therapeutic agent for RA treatment., (© 2024 John Wiley & Sons Ltd.)

Background: Yishen-Tongbi Decoction (YSTB), a traditional Chinese prescription, has been used to improve syndromes of rheumatoid arthritis (RA) for many years. Previous research has shown that YSTB has anti-inflammatory and analgesic properties. However, the underlying molecular mechanism of the anti-RA effects of YSTB remains unclear., Purpose and Study Design: The purpose of this research was to investigate how YSTB affected mice with collagen-induced arthritis (CIA) and RAW264.7 cells induced with lipopolysaccharide (LPS)., Results: The findings show that YSTB could significantly improve the clinical arthritic symptoms of CIA mice (mitigate paw swelling, arthritis score, thymus and spleen indices, augment body weight), downregulated expression of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-17, while upregulated the level of anti-inflammatory like IL-10 and transforming growth factor-β (TGF-β). Meanwhile, YSTB inhibits bone erosion and reduces inflammatory cell infiltration, synovial proliferation, and joint destruction in CIA mice. In addition, we found that YSTB was able to suppress the LPS-induced inflammation of RAW264.7 cells, which was ascribed to the suppression of nitric oxide (NO) production and reactive oxygen species formation (ROS). YSTB also inhibited the production of inducible nitric oxide synthase and reduced the releases of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 in LPS-induced RAW264.7 cells. Furthermore, the phosphorylation expression of JAK2, JAK3, STAT3, p38, ERK and p65 protein could be suppressed by YSTB, while the expression of SOCS3 could be activated., Conclusion: Taken together, YSTB possesses anti-inflammatory and prevention bone destruction effects in RA disease by regulating the JAK/STAT3/SOCS3 signaling pathway., 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 Xu, Jiao, Wu, Yu, Liu, Zhang and Chen.)

Rheumatoid arthritis (RA) is an autoimmune disease that significantly impacts quality of life by disrupting CD4 + T cell immune homeostasis. The identification of a low-side-effect drug for RA treatment is urgently needed. Our previous study suggests that Trichinella spiralis paramyosin ( Ts -Pmy) has immunomodulatory effects, but its potential effect on CD4 + T cell response in RA remains unclear. In this study, we used a murine model to investigate the role of r Ts -Pmy in regulating CD4 + T cell differentiation in collagen-induced arthritis (CIA). Additionally, we assessed the impact of r Ts -Pmy on CD4 + T cell differentiation towards the Th1 and Th17 phenotypes, which are associated with inflammatory responses in arthritis, using in vitro assays. The results demonstrated that r Ts -Pmy administration reduced arthritis severity by inhibiting Th1 and Th17 response while enhancing Treg response. Prophylactic administration of Ts -Pmy showed superior efficacy on CIA compared to therapeutic administration. Furthermore, in vitro assays demonstrated that r Ts -Pmy could inhibit the differentiation of CD4 + T cells into Th1 and Th17 while inducing the production of Tregs, suggesting a potential mechanism underlying its therapeutic effects. This study suggests that Ts -Pmy may ameliorate CIA by restoring the immune balance of CD4 + T cells and provides new insights into the mechanism through which helminth-derived proteins exert their effects on autoimmune diseases.

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease with abnormal differentiation of follicular helper T (Tfh) cells, Total alkaloids of Sophora alopecuroides Linn. (Leguminosae) (TASA) have potential effects on collagen-induced arthritis (CIA) mice, while the mechanism needs further elucidation. The purpose of this study is to explore the regulation of TASA on rheumatoid arthritis and related mechanism., Methods: The proportion of Tfh and B lymphocytes in peripheral blood lymphocytes of RA patients was examined by flow cytometry. We constructed the collagen induced arthritis DBA/1J mice model. Between days 15 and 45 following the first immunization, the mice were treated intraperitoneally with saline, TASA (100, 50, and 25 mg/kg), and dexamethasone (DXM) for 30 days. Molecular biological techniques such as FCM, PCR, ELISA, and Western-blotting were used to examine Tfh cells and associated signal pathways., Results: Our results indicated that the follicular helper T cells and B lymphocytes in rheumatoid arthritis patients were significantly increased compared with the healthy control. The percentage of Tfh cells are correlated with RA related inflammatory factors. Total alkaloids of Sophora alopecuroides Linn. could significantly attenuate joint swelling. Meanwhile, it reduced the frequencies of spleen Tfh, B lymphocytes and the expression of TLR2, TLR9, p-NF-κBp65, CXCR5, Bcl-6, ICOS of ankle joints in CIA mice., Conclusion: Total alkaloids of Sophora alopecuroides Linn. may down-regulate the frequency and function of Tfh cells and inhibit GCB cells via TLRs/NF-κB signal pathway to relieve the immune-pathological progression of CIA mice., Competing Interests: The authors declare that they have no competing interests in this work., (© 2024 Cao et al.)

Aims: We have previously reported reduction of anti-type II collagen (IIC) IgG levels in collagen-induced arthritis (CIA) by Schistosoma mansoni (Sm) and Trichinella spiralis (Ts). To clarify the contribution of the impairment of humoral immunity to their anti-arthritic activities, we herein investigated the relationship between anti-IIC IgG levels and arthritic swelling in Sm- or Ts-infected mice., Methods and Results: Male DBA/1J mice were infected with Sm cercariae or Ts muscle larvae prior to the IIC immunization. In the Sm-infected mice, paw swelling and anti-IIC IgG levels were continuously lower than those of non-infected control group. In contrast, arthritic swelling in the Ts-infected mice only decreased in the early phase of CIA progression, despite the continued impairment of anti-IIC IgG production throughout the experimental period. Correlation coefficients between residual paw swelling and anti-IIC IgG titers were similar or higher in the Sm group than in the control group, but were similar or lower in the Ts group than in the control group., Conclusion: The down-modulations of anti-IIC IgG levels by the two parasitic infections and the correlation analyses suggest that the anti-arthritic activity of Sm was primarily attributed to the modulation of IgG-independent arthritogenic mechanisms and secondarily to the impairment of anti-IIC IgG production. In contrast, Ts could alleviate CIA mainly via the impairment of antibody production., Competing Interests: Declaration of competing interest There are no interests to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Soluble components secreted by Tfh cells are critical for the germinal center responses. In this study, we investigated whether Tfh cells could regulate the B-cell response by releasing small extracellular vesicles (sEVs). Our results showed that Tfh cells promote B-cell differentiation and antibody production through sEVs and that CD40L plays a crucial role in Tfh-sEVs function. In addition, increased Tfh-sEVs were found in mice with collagen-induced arthritis (CIA). Adoptive transfer of Tfh cells significantly exacerbated the severity of CIA; however, the effect of Tfh cells on exacerbating the CIA process was significantly diminished after inhibiting sEVs secretion. Moreover, the levels of plasma Tfh-like-sEVs and CD40L expression on Tfh-like-sEVs in RA patients were significantly higher than those in healthy subjects. In summary, Tfh cell-derived sEVs can enhance the B-cell response, and exacerbate the procession of autoimmune arthritis., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, gut microbiota and its metabolites contribute to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear. In this study, we aimed to investigate whether gut microbiota and their metabolites alter the effects of high fat diet (HFD) on the severity of collagen-induced arthritis (CIA) in mice., Methods: Briefly, mice were divided into normal group (N), CIA model group (C), HFD group (T), and HFD CIA group (CT). Hematoxylin and Eosin staining(HE) and Safranin O-fast green staining were conducted, and levels of blood lipid and inflammatory cytokines were measured. 16S rDNA sequencing technique and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics were performed to explore changes in the microbiota structure to further reveal the pathomechanism of HFD on CIA., Results: HFD aggravated the severity of CIA in mice. The CT group had the highest proportion of microbial abundance of Blautia, Oscillibacter, Ruminiclostridium-9, and Lachnospiraceae UCG 006 at the genus level, but had a lower proportion of Alistipes. Additionally, the fecal metabolic phenotype of the combined CT group shows significant changes, with differential metabolites enriched in 9 metabolic pathways, including primary bile acid biosynthesis, arginine biosynthesis, sphingolipid metabolism, purine metabolism, linoleic acid metabolism, oxytocin signaling pathway, aminoacyl-tRNA biosynthesis, the pentose phosphate pathway, and sphingolipid signaling pathway. Correlation analysis revealed that some of the altered gut microbiota genera were strongly correlated with changes in fecal metabolites, total cholesterol (TC), triglyceride (TG), and inflammatory cytokine levels., Conclusions: This study shows that HFD may aggravate inflammatory reaction in CIA mice by altering the gut microbiota and metabolic pathways., (© 2024. The Author(s).)

Rheumatoid arthritis (RA) is a persistent autoimmune condition with no identified cure currently. Recently, scientists have applied metabolomics to investigate altered metabolic profiles and unique diseases-associated metabolic signatures. Herein, we applied metabolomics approach to analyze serum samples of 41 RA patients and 42 healthy controls (HC) with the aim to characterize RA patients' metabolic profile, investigate related underlying pathological processes, and identify target metabolites. By utilizing ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry, we found 168 proposed metabolites and 45 vital metabolic pathways. Our analysis revealed that deoxyinosine (DI), a metabolite of the purine metabolic pathway, was the most significant reduced metabolite in RA patients. Furthermore, through targeted detection, we confirmed lower concentration of DI in RA patients' peripheral blood. Moreover, DI inhibited lipopolysaccharide-induced inflammation both in vitro and in vivo . We further assessed DI's therapeutic potential in a collagen-induced arthritis (CIA) murine model. The results revealed that DI attenuated CIA, as evidenced by significantly lowered clinical scores of arthritis, alleviated joint swelling, and mitigated bone destruction. Moreover, we elucidated the underlying mechanism by which DI increased the population of myeloid-derived suppressor cells (MDSCs) and suppressed the proliferation of induced T cells. Collectively, these findings suggested that DI potentially ameliorated RA by inducing immunosuppressive MDSCs. The study provides key observations on RA pathogenesis and may contribute to developing novel therapeutic strategies for this debilitating condition., Competing Interests: 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., (© 2024 The Authors.)

Mesenchymal stem cell exosome (MSCs-exo) is a class of products secreted by mesenchymal stem cells (MSCs) that contain various biologically active substances. MSCs-exo is a promising alternative to MSCs due to their lower immunogenicity and lack of ethical constraints. Ginsenoside Rh2 (Rh2) is a hydrolyzed component of the primary active substance of ginsenosides. Rh2 has a variety of pharmacological functions, including anti-inflammatory, anti-tumor, and antioxidant. Studies have demonstrated that gut microbiota and metabolites are critical in developing rheumatoid arthritis (RA). In this study, we constructed a collagen-induced arthritis (CIA) model in rats. We used MSCs-exo combined with Rh2 to treat CIA rats. To observe the effect of MSCs-exo combined with Rh2 on joint inflammation, rat feces were collected for 16 rRNA amplicon sequencing and untargeted metabolomics analysis. The results showed that the arthritis index score and joint swelling of CIA rats treated with MSCs-exo in combination with Rh2 were significantly lower than those of the model and MSCs-exo alone groups. MSCs-exo and Rh2 significantly ameliorated the disturbed gut microbiota in CIA rats. The regulation of Candidatus_Saccharibacteria and Clostridium_XlVb regulation may be the most critical. Rh2 enhanced the therapeutic effect of MSCs-exo compared with the MSCs-exo -alone group. Furthermore, significant changes in gut metabolites were observed in the CIA rat group, and these differentially altered metabolites may act as messengers for host-microbiota interactions. These differential metabolites were enriched into relevant critical metabolic pathways, revealing possible pathways for host-microbiota interactions., Competing Interests: Declaration of Competing Interest The authors declared no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

The biosynthesis of C-reactive protein (CRP) in the liver is increased in inflammatory diseases including rheumatoid arthritis. Previously published data suggest a protective function of CRP in arthritis; however, the mechanism of action of CRP remains undefined. The aim of this study was to evaluate the effects of human CRP on the development of collagen-induced arthritis (CIA) in mice which is an animal model of autoimmune inflammatory arthritis. Two CRP species were employed: wild-type CRP which binds to aggregated IgG at acidic pH and a CRP mutant which binds to aggregated IgG at physiological pH. Ten CRP injections were given on alternate days during the development of CIA. Both wild-type and mutant CRP reduced the incidence of CIA, that is, reduced the number of mice developing CIA; however, CRP did not affect the severity of the disease in arthritic mice. The serum levels of IL-17, IL-6, TNF-α, IL-10, IL-2 and IL-1β were measured: both wild-type and mutant CRP decreased the level of IL-17 and IL-6 but not of TNF-α, IL-10, IL-2 and IL-1β. These data suggest that CRP recognizes and binds to immune complexes, although it was not clear whether CRP functioned in its native pentameric or in its structurally altered pentameric form in the CIA model. Consequently, ligand-complexed CRP, through an as-yet undefined mechanism, directly or indirectly, inhibits the production of IL-17 and eventually protects against the initiation of the development of arthritis. The data also suggest that IL-17, not TNF-α, is critical for the development of autoimmune inflammatory arthritis., 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. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Singh, Prislovsky, Ngwa, Munkhsaikhan, Abidi, Brand and Agrawal.)

Juvenile idiopathic arthritis is an inflammatory disease that can affect the temporomandibular joint (TMJ) and lower jaw growth. Better treatment options are needed, so this study investigated the effect of low-intensity pulsed ultrasound (LIPUS) on TMJ arthritis. Seventy-two 3-week-old male Wistar rats were in vivo microcomputed tomography (micro-CT) scanned and divided into eight groups ( n = 9). These groups were Group 1-TMJ arthritis and immediate LIPUS treatment (20 min/day, 4 weeks); Group 2-immediate LIPUS treatment and no TMJ arthritis; Group 3-TMJ arthritis and no LIPUS; Group 4-no TMJ arthritis and no LIPUS; Group 5-TMJ arthritis and LIPUS treatment with a delayed start by 4 weeks; Group 6-Delayed LIPUS and no TMJ arthritis; Group 7-TMJ arthritis and no (delayed) LIPUS; and Group 8-no TMJ arthritis and no (delayed) LIPUS. Ex vivo micro-CT scanning was completed, and samples were prepared for tissue analysis. Synovitis was observed in the TMJ arthritis (collagen-induced arthritis [CIA]) groups, but the severity appeared greater in the groups without LIPUS treatment. Fibrocartilage and hypertrophic cell layer thicknesses in the CIA group without LIPUS treatment were significantly greater ( p < 0.05). Proteoglycan staining appeared greater in the LIPUS groups. Immediate LIPUS treatment increased the expression of type II collagen, type X collagen, and transforming growth factor-beta 1 (TGF-β1) immunostaining, and CIA (no LIPUS) increased MMP-13, vascular endothelial growth factor, and interleukin-1 beta (IL-1β) immunostaining. LIPUS treatment prevented growth disturbances observed in the CIA groups (no LIPUS) ( p < 0.005). Our results have contributed to the understanding of the uses and limitations of the CIA juvenile rat model and have demonstrated the effects of LIPUS on the TMJ and mandibular growth. This information will help in designing future studies for investigating LIPUS and TMJ arthritis, leading to the development of new treatment options for children with juvenile arthritis in their TMJs.

Recently, long non‑coding RNAs (lncRNAs) have been implicated in several human diseases, including arthritis. However, the role of lncRNAs in regulating the Th17/Treg ratio during the progression of collagen-induced arthritis (CIA) is poorly understood. Therefore, the aim of this study was to determine the role of the lncRNA ENSMUST00000197208 and the P2X7R-NLRP3 inflammasome axis in changes in the Th17/Treg ratio in CIA. To achieve this, the distribution of T cell subgroups in the spleen cells of a CIA mouse model and control mice was examined. Additionally, we examined the expression profile of ENSMUST00000197208 in a CIA mouse model and healthy mice. The results showed that ENSMUST00000197208 expression was significantly upregulated in the CIA models compared with the control group. Additionally, the P2X7R-NLRP3 inflammasome axis participated in the pathogenesis of CIA and knockdown of ENSMUST00000197208 inhibited CD4 + T cell differentiation into Th17 cells. Compared with the control group, joint inflammation was less visible in NLRP3 knockout mice. Additionally, the P2X7R-NLRP3 inflammasome axis, which is downstream of ENSMUST00000197208, can be positively targeted and regulated by ENSMUST00000197208 through miR-107. Overall, the findings of this study showed that the "lncRNA ENSMUST00000197208-miR 107-P2X7R/NLRP3" axis plays an important role in CIA and knocking down ENSMUST00000197208 can efficiently inhibit Th17 differentiation by suppressing the P2X7R-NLRP3 inflammasome axis. Therefore, targeting this axis may represent a novel strategy for arthritis treatment., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by persistent synovial inflammation and joint degradation, posing challenges in the development of effective treatments. Nuciferine, an alkaloid found in lotus leaf, has shown promising anti-inflammatory and anti-tumor effects, yet its efficacy in RA treatment remains unexplored. This study investigated the antiproliferative effects of nuciferine on the MH7A cell line, a human RA-derived fibroblast-like synoviocyte, revealing its ability to inhibit cell proliferation, promote apoptosis, induce apoptosis, and cause G 1 /S phase arrest. Additionally, nuciferine significantly reduced the migration and invasion capabilities of MH7A cells. The therapeutic potential of nuciferine was further evaluated in a collagen-induced arthritis (CIA) rat model, where it markedly alleviated joint swelling, synovial hyperplasia, cartilage injury, and inflammatory infiltration. Nuciferine also improved collagen-induced bone erosion, decreased pro-inflammatory cytokines and serum immunoglobulins (IgG, IgG1, IgG2a), and restored the balance between T helper (Th) 17 and regulatory T cells in the spleen of CIA rats. These results indicate that nuciferine may offer therapeutic advantages for RA by decreasing the proliferation and invasiveness of FLS cells and correcting the Th17/Treg cell imbalance in CIA rats., (Copyright © 2024 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.)

Objective: Tolerogenic dendritic cells (tolDCs) have emerged as a potential treatment for rheumatoid arthritis (RA). However, the detailed mechanism requires further investigation. In this study, we aimed to explore the effects of tolDCs on T-cell differentiation and NLRP3-mediated pyroptosis in a collagen-induced arthritis (CIA) rat model., Methods: TolDCs were induced using NF-κB ODN decoy. The efficacy of tolDCs intervention in alleviating arthritis symptoms was evaluated in CIA rats. Flow cytometry was employed to analyze CD4 + T-cell subpopulations, while scanning electron microscopy was utilized to observe pyroptosis morphology. Immunohistochemistry was used to assess the expression of pyroptosis-associated proteins., Results: TolDCs intervention significantly reduced joint inflammation and damage in CIA rats. Moreover, it successfully restored the balance of Th1/Th2 cells as well as the balance of Treg/Th17 cells. Furthermore, tolDCs intervention effectively suppressed NLRP3-mediated pyroptosis in the synovium, decreasing the release of IL-1β and IL-18., Conclusion: Our findings underscore the efficacy of tolDCs in attenuating CIA progression through modulation of CD4 + T-cell subpopulations and inhibition of NLRP3-mediated pyroptosis., 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.)

Background: Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammatory reactions and tissue damage in the joints. Long-term drug use in clinical practice is often accompanied by adverse reactions. Extracorporeal photopheresis (ECP) is an immunomodulatory therapy with few side effects, offering a potential and safe therapeutic alternative for RA through the induction of immune tolerance. This study aimed to investigate the therapeutic effects of ECP on RA using a collagen-induced arthritis (CIA) murine model, as well as to explore its immunomodulatory effects in vivo. Additionally, particular attention was given to the significant role of monocytes during the ECP process., Methods: A murine model of rheumatoid arthritis was established by administering two injections of bovine type II collagen to DBA/1J mice. ECP, ECP-MD (mononuclear cells were depleted during the ECP), MTX, and PBS treatment were applied to the CIA mice. During the treatment process, clinical scores and body weight changes of CIA mice were closely monitored. After six treatment sessions, micro-CT images of the hind paws from live mice were captured. Ankle joints and paws of the mice were collected and processed for histological evaluation. Spleen samples were collected to measure the Th17/Treg cells ratio, and serum samples were collected to assess cytokine and anti-type II collagen IgG levels. Monocytes and dendritic cells populations before and after ECP in vitro were detected by flow cytometry., Result: ECP therapy significantly attenuated the progression of CIA, alleviated the severity of clinical symptoms in CIA mice and effectively suppressed synovial hyperplasia, inflammation, and cartilage damage. There was an expansion in the percentage of CD3 + CD4 + CD25 + FoxP3 + Tregs and a decrease in CD3 + CD4 + IL17A + Th17 cells in vivo. Furthermore, ECP reduced the serum levels of pro-inflammatory cytokines IL-6 (53.47 ± 7.074 pg/mL vs 5.142 ± 1.779 pg/mL, P < 0.05) and IL-17A (3.077 ± 0.401 pg/mL vs 0.238 ± 0.082 pg/mlL, P < 0.0001) compared with PBS. Interestingly, the depletion of monocytes during the ECP process did not lead to any improvement in clinical symptoms or histological scores in CIA mice. Moreover, the imbalance in the Th17/Treg cells ratio became even more pronounced, accompanied by an augmented secretion of pro-inflammatory cytokines IL-6 and IL-17A. In vitro, compared with cells without ECP treatment, the proportion of CD11b + cells were significantly reduced (P < 0.01), the proportion of CD11c + cells were significantly elevated (P < 0.001) 24 h after ECP treatment. Additionally, the expression of MHC II (P < 0.0001), CD80 (P < 0.01), and CD86 (P < 0.001) was downregulated in CD11c + cells 24 h after ECP treatment., Conclusion: Our study demonstrates that ECP exhibits a therapeutic effect comparable to conventional therapy in CIA mice, and the protective mechanisms of ECP against RA involve Th17/Treg cells ratio, which result in decreased IL-6 and IL-17A. Notably, monocytes derived from CIA mice are an indispensable part to the efficacy of ECP treatment, and the proportion of monocytes decreased and the proportion of tolerogenic dendritic cells increased after ECP treatment in vitro., (© 2024. The Author(s).)

Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease characterized by articular cartilage destruction, bone destruction and synovial hyperplasia. It has been suggested that Vigeo, a mixture of Eleutherococcus senticosus , Achyranthes japonica and Atractylodes japonica fermented with Korean nuruk , has an anti-osteoporotic effect in a mouse model of inflammation-mediated bone loss. The present study evaluated the therapeutic effects of Vigeo in RA using a collagen-induced arthritis (CIA) mouse model. DBA/1J mice were immunized with bovine type II collagen on days 0 and 21 and Vigeo was administered daily for 20 days beginning the day after the second type II collagen injection. The mice were sacrificed on day 42 and the joint tissues were anatomically separated and subjected to micro computed tomography and histological analyses. In addition, the serum levels of TNF-α, IL-6 and IL-1β were determined by enzyme-linked immunosorbent assays. CIA in DBA/1J mice caused symptoms of RA, such as joint inflammation, cartilage destruction and bone erosion. Treatment of CIA mice with Vigeo markedly decreased the symptoms and cartilage pathology. In addition, radiological and histological analyses showed that Vigeo attenuated bone and cartilage destruction. The serum TNF-α, IL-6 and IL-1β levels following oral Vigeo administration were also reduced when compared with those in CIA mice. The present study revealed that Vigeo suppressed arthritis symptoms in a CIA-RA mouse model, including bone loss and serum levels of TNF-α, IL-6 and IL-1β., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2024 Cheon et al.)

Rheumatoid arthritis (RA) is a chronic autoimmune disease in which immune cells and inflammatory cytokines are abnormally activated, leading to immunoregulatory dysfunction in the body and triggering systemic inflammatory responses. The interaction between CXC chemokine receptor 4 (CXCR4) and heterotrimeric G-protein α-subunit Gαq (Gnαq) activates phospholipase Cβ (PLCβ), which influences the expression of downstream effectors and participates widely in the onset and development of various diseases, thus suggesting the potential involvement of these molecules in RA pathogenesis. Therefore, the present study aimed to determine whether the CXCR 4- Gnαq - PLCβ signaling pathway participates in the onset and development of RA. Using a collagen-induced arthritis (CIA) rat model, we found that compared with the control (healthy) rat group, CIA rats exhibited highly time-dependent arthritis, with the maximum arthritis score occurring in week 3. In contrast to the splenic and joint tissue of control rats, CIA rats showed obvious hyperplasia in the lymphoid white pulp and main germination centers of the spleen, narrowing of joint cavities, and inflammatory cellular infiltration on articular surfaces. The serum levels of expression of IL-1β, IL-4, IL-6, and TNF-α were significantly elevated ( P  < 0.05, P  < 0.01). Core genes of the CXCR 4- Gnαq - PLCβ pathway, namely CXCR 4, Gnαq , PLCβ 1, MMP 1, and MMP 3, also showed a significant increase in mRNA and protein expression levels ( P  < 0.05, P  < 0.01). Proteins related to the CXCR4-Gnαq-PLCβ pathway were mainly localized to the red and white pulp regions in the spleen as well as in stromal, endothelial, and subdifferentiated synovial cells in the joints. These results indicated that CXCR4 is dependent on Gnαq for inducing the expression of PLCβ1 and stimulation of secretion of inflammatory cytokines by inflammatory cells. This consequently affects the expression of matrix metalloproteinases (MMPs), which serve as downstream effectors, thereby promoting RA pathogenesis. Our findings play an important role in elucidating the mechanisms of the onset and development of RA., Competing Interests: 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., (© 2024 The Authors.)

Rheumatoid arthritis (RA) is recognized as an autoimmune joint disease driven by T cell responses to self (or modified self or microbial mimic) antigens that trigger and aggravate the inflammatory condition. Newer treatments of RA employ monoclonal antibodies or recombinant receptors against cytokines or immune cell receptors as well as small-molecule Janus kinase (JAK) inhibitors to systemically ablate the cytokine or cellular responses that fuel inflammation. Unlike these treatments, a therapeutic vaccine, such as CEL-4000, helps balance adaptive immune homeostasis by promoting antigen-specific regulatory rather than inflammatory responses, and hence modulates the immunopathological course of RA. In this review, we discuss the current and proposed therapeutic products for RA, with an emphasis on antigen-specific therapeutic vaccine approaches to the treatment of the disease. As an example, we describe published results of the beneficial effects of CEL-4000 vaccine on animal models of RA. We also make a recommendation for the design of appropriate clinical studies for these newest therapeutic approaches, using the CEL-4000 vaccine as an example. Unlike vaccines that create or boost a new immune response, the clinical success of an immunomodulatory therapeutic vaccine for RA lies in its ability to redirect autoreactive pro-inflammatory memory T cells towards rebalancing the "runaway" immune/inflammatory responses that characterize the disease. Human trials of such a therapy will require alternative approaches in clinical trial design and implementation for determining safety, toxicity, and efficacy. These approaches include adaptive design (such as the Bayesian optimal design (BOIN), currently employed in oncological clinical studies), and the use of disease-related biomarkers as indicators of treatment success., Competing Interests: Authors DZ and RC were employed by CEL-SCI Corporation. The remaining 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 Zimmerman, Szekanecz, Markovics, Rosenthal, Carambula and Mikecz.)

Objectives: The purpose of this study is to investigate whether fat mass and obesity-associated protein (FTO) and NOL1/NOP2/Sun domain family member 2 (NSUN2) mediated RNA methylation is associated with RA pathology., Methods: We studied the anti-rheumatoid arthritis (RA) mechanism mediated by FTO and NSUN2 in RA samples and collagen-induced arthritis (CIA) rats using real time qPCR (RT-qPCR), western blot, immunofluorescence, and other methods., Key Findings: The expression of NSUN2 was significantly increased in both RA patients and CIA rats compared with normal controls. Knockdown of NSUN2 blocked the Wnt/β-catenin signaling pathway and inhibited RA pathological factors such as MMP3, fibronectin, and interleukins. FTO overexpression inhibited RA by inhibiting the expression of NSUN2, up-regulating the level of SFRP1 protein, and blocking the Wnt/β-catenin signaling pathway. NSUN2 overexpression interfered with the inhibitory effects of FTO on the Wnt/β-catenin signaling pathway and RA pathology, which further verified that FTO inhibited RA through the NSUN2/SFRP1/Wnt/β-catenin signal axis., Conclusions: FTO and NSUN2 are important factors of RA, and this work provides new potential diagnostic biomarkers and therapeutic targets for RA. We also reveal a gene expression regulation pattern of the interaction between m6A and m5C. revealing the pathogenesis of RA from the perspective of RNA methylation., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Fibroblast-like synoviocytes (FLS) play a critical role on the exacerbation and deterioration of rheumatoid arthritis (RA). Aberrant activation of FLS pyroptosis signaling is responsible for the hyperplasia of synovium and destruction of cartilage of RA. This study investigated the screened traditional Chinese medicine berberine (BBR), an active alkaloid extracted from the Coptis chinensis plant, that regulates the pyroptosis of FLS and secretion of inflammatory factors in rheumatoid arthritis., Methods: First, BBR was screened using a high-throughput drug screening strategy, and its inhibitory effect on RA-FLS was verified by in vivo and in vitro experiments. Second, BBR was intraperitoneally administrated into the collagen-induced arthritis rat model, and the clinical scores, arthritis index, and joint HE staining were evaluated. Third, synovial tissues of CIA mice were collected, and the expression of NLRP3, cleaved-caspase-1, GSDMD-N, Mst1, and YAP was detected by Western blot., Results: The administration of BBR dramatically alleviated the severity of collagen-induced arthritis rat model with a decreased clinical score and inflammation reduction. In addition, BBR intervention significantly attenuates several pro-inflammatory cytokines (interleukin-1β, interleukin-6, interleukin-17, and interleukin-18). Moreover, BBR can reduce the pyroptosis response (caspase-1, NLR family pyrin domain containing 3, and gasdermin D) of the RA-FLS in vitro, activating the Hippo signaling pathway (Mammalian sterile 20-like kinase 1, yes-associated protein, and transcriptional enhanced associate domains) so as to inhibit the pro-inflammatory effect of RA-FLS., Conclusion: These results support the role of BBR in RA and may have therapeutic implications by directly repressing the activation, migration of RA-FLS, which contributing to the attenuation of the progress of CIA. Therefore, targeting PU.1 might be a potential therapeutic approach for RA. Besides, BBR inhibited RA-FLS pyroptosis by downregulating of NLRP3 inflammasomes (NLRP3, caspase-1) and eased the pro-inflammatory activities via activating the Hippo signaling pathway, thereby improving the symptom of CIA., (© 2024. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Background: The inflammatory cascade mediated by macrophages and T cells is considered to be an important factor in promoting the progression of rheumatoid arthritis (RA). Our previous study found that berberine (BBR) can therapeutically impact adjuvant arthritis (AA) in rats through the regulation of macrophage polarization and the balance of Th17/Treg. However, whether BBR's effects on CD4 + T cells response are related to its suppression of M1 macrophage still unclear., Purpose: The study aimed to estimate the mechanism of BBR in regulating the immunometabolism and differentiation of CD4 + T cells are related to exosome derived from M1-macrophage (M1-exo)., Study-Design/methods: Mice model of collagen-induced arthritis (CIA) was established to investigate the antiarthritic effect of BBR was related with regulation of M1-exo to balance T cell subsets. Bioinformatics analysis using the GEO database and meta-analysis. In vitro, we established the co-culture system involving M1-exo and CD4 + T cells to examine whether BBR inhibits CD4 + T cell activation and differentiation by influencing M1-exo-miR155. Exosome was characterized using transmission electron microscopy and western blot analysis, macrophage and CD4 + T cell subpopulation were detected by flow cytometry. Further, the metabolic profiles of CD4 + T cells were assessed by ECAR, OCR, and the level of glucose, lactate, intracellular ATP., Result: BBR reinstates CD4 + T cell homeostasis and reduces miR155 levels in both M1-exo and CD4 + T cells obtained from mice with CIA. In vitro, we found exosomes are indispensable for M1-CM on T lymphocyte activation and differentiation. BBR reversed M1-exo facilitating the activation and differentiation of CD4 + T cells. Furthermore, BBR reversed glycolysis reprogramming of CD4 + T cells induced by M1-exo, while these regulation effects were significantly weakened by miR155 mimic., Conclusion: The delivery of miR-155 by M1-exo contributes to CD4 + T cell immunometabolism dysfunction, a process implicated in the development of RA. The anti-arthritic effect of BBR is associated with the suppression of glycolysis and the disruption of CD4 + T cell subsets balance, achieved by reducing the transfer of M1-exo-miR155 into T cells., Competing Interests: Declaration of Competing Interest We declare that we have no competing financial interests or personal relationships with other people or organizations that can inappropriately influence our work., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

The role of Galectin-9 (Gal-9) in the pathogenesis of rheumatoid arthritis (RA) remains unclear. This study aimed to investigate the mechanism of action and therapeutic potential of Gal-9 in RA. We detected Gal-9 expression in clinical samples, explored the mechanism of function of Gal-9 by knockdown and overexpression in fibroblast-like synoviocytes (FLSs), and further verified it in collagen-induced arthritis (CIA) model. We found that the levels of Gal-9 were considerably elevated in RA synovium than in osteoarthritis (OA) patients. A substantial decrease of Gal-9 was demonstrated after tumor necrosis factor (TNF-α) inhibitor treatment in the plasma of patients with RA. Additionally, transcriptome sequencing revealed that Gal-9 was involved in the regulation of the TNF-α pathway. Gal-9 was considerably upregulated after TNF-α stimulation in FLSs, and knockdown of Gal-9 substantially inhibited TNF-α activated proliferation, migration and inflammatory response. According to cell transcriptome sequencing results, we further confirmed that Gal-9 could achieve these effects by interacting with MAFB and affecting PI3K/AKT/mTOR pathway. Finally, we knocked down Gal-9 on the CIA model and found that it could alleviate the progression of arthritis. In conclusion, our study revealed that the knockdown of Gal-9 could inhibited TNF-α induced activation in RA through MAFB, PI3K/AKT/mTOR., 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 © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Rheumatoid arthritis (RA) is a chronic inflammatory and destructive arthritis, characterized by inflammatory infiltration and bone destruction. Huangqi Guizhi Wuwu Decoction (HGWD) is traditional Chinese medicine, which has been applied in the treatment of RA in clinical. The aim of this study was to investigate the therapeutic effect of HGWD on collagen-induced arthritis (CIA) mouse model., Methods: DBA/1J female mice were used to establish the collagen-induced arthritis (CIA) model. HGWD was administered intragastrically once a day for four weeks starting on the 22nd day after the first immunization. The body weight, hind paw thickness and clinical score were measured every five days. Gait analysis, histopathological staining, enzyme-linked immunosorbent assay (ELISA), ultrasound imaging and micro-computed tomography imaging were performed to determine the effects of HGWD treatment on inflammation and bone structure in this model. Moreover, Real-time PCR and Western blot analysis were used to detect inflammatory factors mRNA and protein levels after HGWD intervention in RAW 264.7 cells., Results: HGWD attenuated symptoms of arthritis, suppressed inflammatory synovium area and the serum levels of inflammatory factors, inhibited joint space enlargement in the knee and ankle joints, reduced numbers of osteoclasts, protected bone destruction, as well as improved motor function. HGWD decreased the expression of mRNA for inflammatory factors and the protein expression levels of p-NF-кB and IL-17., Conclusion: These results suggested that HGWD suppresses inflammation, attenuates bone erosion and maintains motor function in collagen-induced arthritis mice., Competing Interests: 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., (© 2024 Tianjin Press of Chinese Herbal Medicines. Published by ELSEVIER B.V.)

Rheumatoid arthritis is a systemic autoimmune inflammatory disease that affects millions of people worldwide. There are multiple disease-modifying anti-rheumatic drugs available; however, many patients do not respond to any treatment. A disintegrin and metalloproteinase 10 has been suggested as a potential new target for RA due to its role in the release of multiple pro- and anti-inflammatory factors from cell surfaces. In the present study, we determined the pharmacokinetic parameters and in vivo efficacy of a compound CID3117694 from a novel class of non-zinc-binding inhibitors. Oral bioavailability was demonstrated in the blood and synovial fluid after a 10 mg/kg dose. To test efficacy, we established the collagen-induced arthritis model in mice. CID3117694 was administered orally at 10, 30, and 50 mg/kg/day for 28 days. CID3117694 was able to dose-dependently improve the disease score, decrease RA markers in the blood, and decrease signs of inflammation, hyperplasia, pannus formation, and cartilage erosion in the affected joints compared to the untreated control. Additionally, mice treated with CID 3117694 did not exhibit any clinical signs of distress, suggesting low toxicity. The results of this study suggest that the inhibition of ADAM10 exosite can be a viable therapeutic approach to RA.

Loss of tolerance to self-antigens is considered to be one of the initial reasons for the onset of rheumatoid arthritis (RA). Identification of self-antigens and evaluation of autoreactive antibodies can foster understanding of the pathogenesis of the disease and the development of new therapeutics. By detection of responses to a particular self-antigen, such as α-enolase, keratin, fibrinogen, fibronectin, collagen, or vimentin, in patient- and animal model-derived samples, high-affinity T-cell receptor-dependent activation of autoreactive T cells to self-antigens can be elucidated. This chapter introduces a simple method to estimate T-cell-autoreactive responses to type II collagen (CII) in a murine collagen-induced arthritis model. A limiting dilution system is established in order to assess CII-dependent T-cell responses, which are reflected by the level of cytokine release., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Due to the limitations of using patient-derived samples for systemic kinetic studies in rheumatoid arthritis (RA) research, animal models are helpful for further understanding the pathophysiology of RA and seeking potential therapeutic targets or strategies. The collagen-induced arthritis (CIA) model is one of the standard RA models used in preclinical research. The CIA model shares several pathological features with RA, such as breach of tolerance and generation of autoantibodies targeting collagen, synovial inflammatory cell infiltration, synovial hyperplasia, cartilage destruction, and bone erosion. In this chapter, a protocol for the successful induction of CIA in mice is described. In this protocol, CIA is induced by active immunization by inoculation with type II heterologous collagen in Freund's adjuvant in susceptible DBA/1 mice., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Macaques are useful animal models for studying the pathogenesis of rheumatoid arthritis (RA) and the development of anti-rheumatic drugs. The purpose of this study was to identify the major histocompatibility complex (MHC) polymorphisms associated with the pathology of collagen-induced arthritis (CIA) and anti-collagen IgG induction in a cynomolgus macaque model, as MHC polymorphisms affect the onset of CIA in other animal models. Nine female Filipino cynomolgus macaques were immunized with bovine type II collagen (b-CII) to induce CIA, which was diagnosed clinically by scoring the symptoms of joint swelling over 9 weeks. MHC polymorphisms and anti-b-CII antibody titers were compared between symptomatic and asymptomatic macaques. Four of 9 (44%) macaques were defined as the CIA-affected group. Anti-b-CII IgG in the affected group increased in titer approximately 3 weeks earlier compared with the asymptomatic group. The mean plasma IgG1 titer in the CIA-affected group was significantly higher (p < 0.05) than that of the asymptomatic group. Furthermore, the cynomolgus macaque MHC (Mafa)-DRB1*10:05 or Mafa-DRB1*10:07 alleles, which contain the well-documented RA-susceptibility five amino acid sequence known as the shared epitope (SE) in positions 70 to 74, with valine at position 11 (Val11, V11) and phenylalanine at position 13 (Phe13, F13), were detected in the affected group. In contrast, no MHC polymorphisms specific to the asymptomatic group were identified. In conclusion, the presence of V11 and F13 along with SE in the MHC-DRB1 alleles seems essential for the production of IgG1 and the rapid induction of severe CIA in female Filipino cynomolgus macaques., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Disease severity in murine arthritis models, such as collagen-induced arthritis (CIA), is commonly assessed by clinical scoring of paw swelling and histological examination of joints. Clinical scoring using a qualitative scoring system of paw inflammation (paw thickness, width, or volume) over time is the standard method used for subjective quantification of arthritis activity. To evaluate paw swelling status, a quantitative method using three-dimensional T2-weighted flash sequence magnetic resonance imaging (MRI) is introduced. The efficacy of a therapeutic approach can be semiologically quantified using a clinical scoring system and an index of paw inflammation in CIA mice., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Objectives: To explore the novel function of MYO6 on Osteoclast differentiation and its joint destruction capacity in Rheumatoid arthritis mice model., Methods: We examined joint erosion in a collagen-induced arthritis (CIA) mouse model using micro-CT, with the mice having a MYO6 knockout background. Inflammatory cytokines were analyzed using an enzyme-linked immunosorbent assay (ELISA). In vitro, we investigated the osteoclastogenesis ability of bone marrow-derived macrophages isolated from MYO6 -/- mice and their littermate controls, examining both morphological and functional differences. Furthermore, we explored podosome formation and endosome maturation using immunofluorescence staining., Results: We found that MYO6 deficiency attenuated arthritis development and bone destruction in CIA mice as well as impaired osteoclast differentiation by inhibiting NFATc1 induction. Our findings indicate that MYO6 is essential for the organization of podosomes by modulating the FAK/AKT and integrin-β3/Src pathways. MYO6 also mediates endosome transportation by regulating the expression of Rab5 and GM130. This may impact the maintenance and functionality of the ruffled border, as well as the regulation of autophagy in osteoclasts., Conclusion: Our results demonstrated a critical function of MYO6 in osteoclast differentiation and its potential relevance in experimental arthritis., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The pathogenic anti-citrullinated protein antibodies (ACPA) are thought to play a vital role in the initiation and immune maintenance of rheumatoid arthritis (RA). However, it is noteworthy that ACPA is not a salient characteristic of any conventional RA animal model. Porphyromonas gingivalis (Pg) is the first microorganism identified to induce citrullination and a target of autoantibodies in early rheumatoid arthritis (RA). Thus, we employed C3H mice with specific MHC types and combined Pg infection with collagen immunity to develop an animal model of ACPA-positive RA. The resulting model exhibited citrullination characteristics, as well as pathological and immune cell changes. 1) Mice showed a significant increase in ACPA levels, and various organs and tissues exhibited elevated levels of citrullinated protein. 2) The mice experienced heightened pain, inflammation, and bone destruction. 3) The spleen and lymph nodes of the mice showed a significant increase in the proportion of Tfh-GCB cell subpopulations responsible for regulating autoantibody production. In conclusion, the C3H mouse model of Pg infection with collagen immunity demonstrated significant alterations in ACPA levels, citrullinated protein expression, and immune cell subpopulations, which could be a crucial factor leading to increased pain, inflammation, and bone destruction., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interests regarding the publication of this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

IL-2 inducible T cell kinase (ITK) is critical in T helper subset differentiation and its inhibition has been suggested for the treatment of T cell-mediated inflammatory diseases. T follicular helper (Tfh), Th17 and regulatory T cells (Treg) also play important roles in the development of rheumatoid arthritis (RA), while the role of ITK in the development of RA and the intricate balance between effector T and regulatory T cells remains unclear. Here, we found that CD4 + T cells from RA patients presented with an elevated ITK activation. ITK inhibitor alleviated existing collagen-induced arthritis (CIA) and reduced antigen specific antibody production. Blocking ITK kinase activity interferes Tfh cell generation. Moreover, ITK inhibitor effectively rebalances Th17 and Treg cells by regulating Foxo1 translocation. Furthermore, we identified dihydroartemisinin (DHA) as a potential ITK inhibitor, which could inhibit PLC-γ1 phosphorylation and the progression of CIA by rebalancing Th17 and Treg cells. Out data imply that ITK activation is upregulated in RA patients, and therefore blocking ITK signal may provide an effective strategy to treat RA patients and highlight the role of ITK on the Tfh induction and RA progression., Competing Interests: Declaration of Competing Interest AA declares research funding from the 3M Company and WH received research support from MegaRobo Technologies Co., Ltd.. The other authors declare no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objective: The collagen-induced arthritis (CIA) model is the most commonly studied autoimmune model of rheumatoid arthritis (RA). In this study, we investigated the usefulness of collagen type II emulsified in Freund's incomplete adjuvant (CII/IFA) as a suitable method for establishing RA in Lewis rats. The aim of the present study was to present a straightforward and effective method for inducing CIA in rats., Materials and Methods: In this experimental study, animals were divided into two equal groups (n=5); control and CIA. Five rats were injected intradermally at the base of the tail with a 0.2 ml CII/IFA emulsion. On the seventh day, a 0.1 ml CII/IFA emulsion booster was injected. Arthritis symptoms that arose were evaluated at clinical, histological, radiological, and at protein expression levels to find out if the disease had been induced successfully., Results: Our finding showed a decreasing trend in the body weight during the RA induction period, while the arthritis score and paw thickness were increased during this period. The results of the enzyme-linked immunosorbent assay (ELISA) for serum samples revealed that the levels of proinflammatory cytokines, interleukin (IL)-1β, IL-6, IL-17, and tumor necrosis factor (TNF)-α and anti-CII IgG were significantly increased in CIA rats compared to the control group. After CIA induction, the level of anti-inflammatory protein IL-10 was decreased significantly. Radiographic examination of the hind paws showed soft tissue swelling, bone erosion, and osteophyte formation in CIA rats. Additionally, based on histological evaluations, the hind paws of the CIA group showed pannus formation, synovial hyperplasia, and bone and cartilage destruction., Conclusion: It seems that CII/IFA treatment can be an appropriate and effective method to induce RA disease in Lewis rats. This well-established and well-characterized CIA model in female Lewis rats could be considered to study aspects of RA and develop novel anti-arthritic agents.