Mouse Model Of Arthritis Research Articles

CXCL5 activates CXCR2 in nociceptive sensory neurons to drive joint pain and inflammation in experimental gouty arthritis.

Gouty arthritis evokes joint pain and inflammation. Mechanisms driving gout pain and inflammation remain incompletely understood. Here we show that CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to drive gout pain and inflammation. CXCL5 expression was increased in ankle joints of gout arthritis model mice, whereas CXCR2 showed expression in joint-innervating sensory neurons. CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to trigger TRPA1 activation, resulting in hyperexcitability and pain. Neuronal CXCR2 coordinates with neutrophilic CXCR2 to contribute to CXCL5-induced neutrophil chemotaxis via triggering CGRP- and substance P-mediated vasodilation and plasma extravasation. Neuronal Cxcr2 deletion ameliorates joint pain, neutrophil infiltration and gait impairment in model mice. We confirmed CXCR2 expression in human dorsal root ganglion neurons and CXCL5 level upregulation in serum from male patients with gouty arthritis. Our study demonstrates CXCL5-neuronal CXCR2-TRPA1 axis contributes to gouty arthritis pain, neutrophil influx and inflammation that expands our knowledge of immunomodulation capability of nociceptive sensory neurons.

A DNA origami device spatially controls CD95 signalling to induce immune tolerance in rheumatoid arthritis.

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.

Employing Feature Selection Algorithms to Determine the Immune State of Mice Model of Rheumatoid Arthritis.

The immune response is a dynamic process by which the body determines whether an antigen is self or nonself. The state of this dynamic process is defined by the relative balance and population of inflammatory and regulatory actors which comprise this decision making process. The goal of immunotherapy as applied to, e.g. Rheumatoid Arthritis (RA), then, is to bias the immune state in favor of the regulatory actors - thereby shutting down autoimmune pathways in the response. While there are several known approaches to immunotherapy, the effectiveness of the therapy will depend on how this intervention alters the evolution of this state. Unfortunately, this process is determined not only by the dynamics of the process, but the state of the system at the time of intervention - a state which is difficult if not impossible to determine prior to application of the therapy. To identify such states we consider a mouse model of RA (Collagen-Induced Arthritis (CIA)) immunotherapy; collect high dimensional data on T cell markers and populations of mice after treatment with a recently developed immunotherapy for CIA; and use feature selection algorithms in order to select a lower dimensional subset of this data which can be used to predict both the full set of T cell markers and populations, along with the efficacy of immunotherapy treatment.

Altered Iron-Mediated Metabolic Homeostasis Governs the Efficacy and Toxicity of Tripterygium Glycosides Tablets Against Rheumatoid Arthritis

Rheumatoid arthritis (RA), a globally increasing autoimmune disorder, is associated with increased disability rates due to the disruption of iron metabolism. Tripterygium glycoside tablets (TGTs), a Tripterygium wilfordii Hook. f. (TwHF)-based therapy, exhibit satisfactory clinical efficacy for RA treatment. However, drug-induced liver injury (DILI) remains a critical issue that hinders the clinical application of TGTs, and the molecular mechanisms underlying the efficacy and toxicity of TGTs in RA have not been fully elucidated. To address this problem, we integrated clinical multi-omics data associated with the anti-RA efficacy and DILI of TGTs with the chemical and target profiling of TGTs to perform a systematic network analysis. Subsequently, we identified effective and toxic targets following experimental validation in a collagen-induced arthritis (CIA) mouse model. Significantly different transcriptome–protein–metabolite profiles distinguishing patients with favorable TGTs responses from those with poor outcomes were identified. Intriguingly, the clinical efficacy and DILI of TGTs against RA were associated with metabolic homeostasis between iron and bone and between iron and lipids, respectively. Particularly, the signal transducer and activator of transcription 3 (STAT3)–hepcidin (HAMP)/lipocalin 2 (LCN2)–tartrate-resistant acid phosphatase type 5 (ACP5) and STAT3–HAMP–acyl-CoA synthetase long-chain family member 4 (ACSL4)–lysophosphatidylcholine acyltransferase 3 (LPCAT3) axes were identified as key drivers of the efficacy and toxicity of TGTs. TGTs play dual roles in ameliorating CIA-induced pathology and in inducing hepatic dysfunction, disruption of lipid metabolism, and hepatic lipid peroxidation. Notably, TGTs effectively reversed “iron–bone” disruptions in the inflamed joint tissues of CIA mice by inhibiting the STAT3–HAMP/LCN2–ACP5 axis, subsequently leading to “iron–lipid” disturbances in the liver tissues via modulation of the STAT3–HAMP–ACSL4–LPCAT3 axis. Additional bidirectional validation experiments were conducted using MH7A and AML12 cells to confirm the bidirectional regulatory effects of TGTs on key targets. Collectively, our data highlight the association between iron-mediated metabolic homeostasis and the clinical efficacy and toxicity of TGT in RA therapy, offering guidance for the rational clinical use of TwHF-based therapy with dual therapeutic and toxic potential.

ScDrugPrio: a framework for the analysis of single-cell transcriptomics to address multiple problems in precision medicine in immune-mediated inflammatory diseases.

Ineffective drug treatment is a major problem for many patients with immune-mediated inflammatory diseases (IMIDs). Important reasons are the lack of systematic solutions for drug prioritisation and repurposing based on characterisation of the complex and heterogeneous cellular and molecular changes in IMIDs. Here, we propose a computational framework, scDrugPrio, which constructs network models of inflammatory disease based on single-cell RNA sequencing (scRNA-seq) data. scDrugPrio constructs detailed network models of inflammatory diseases that integrate information on cell type-specific expression changes, altered cellular crosstalk and pharmacological properties for the selection and ranking of thousands of drugs. scDrugPrio was developed using a mouse model of antigen-induced arthritis and validated by improved precision/recall for approved drugs, as well as extensive in vitro, in vivo, and in silico studies of drugs that were predicted, but not approved, for the studied diseases. Next, scDrugPrio was applied to multiple sclerosis, Crohn's disease, and psoriatic arthritis, further supporting scDrugPrio through prioritisation of relevant and approved drugs. However, in contrast to the mouse model of arthritis, great interindividual cellular and gene expression differences were found in patients with the same diagnosis. Such differences could explain why some patients did or did not respond to treatment. This explanation was supported by the application of scDrugPrio to scRNA-seq data from eleven individual Crohn's disease patients. The analysis showed great variations in drug predictions between patients, for example, assigning a high rank to anti-TNF treatment in a responder and a low rank in a nonresponder to that treatment. We propose a computational framework, scDrugPrio, for drug prioritisation based on scRNA-seq of IMID disease. Application to individual patients indicates scDrugPrio's potential for personalised network-based drug screening on cellulome-, genome-, and drugome-wide scales. For this purpose, we made scDrugPrio into an easy-to-use R package ( https://github.com/SDTC-CPMed/scDrugPrio ).

An anti-TNF-glucocorticoid receptor modulator antibody-drug conjugate is efficacious against immune-mediated inflammatory diseases.

Glucocorticoids (GCs) are efficacious drugs used for treating many inflammatory diseases, but the dose and duration of administration are limited because of severe side effects. We therefore sought to identify an approach to selectively target GCs to inflamed tissue. Previous work identified that anti-tumor necrosis factor (TNF) antibodies that bind to transmembrane TNF undergo internalization; therefore, an anti-TNF antibody-drug conjugate (ADC) would be mechanistically similar, where lysosomal catabolism could release a GC receptor modulator (GRM) payload to dampen immune cell activity. Consequently, we have generated an anti-TNF-GRM ADC with the aim of inhibiting pro-inflammatory cytokine production from stimulated human immune cells. In an acute mouse model of contact hypersensitivity, a murine surrogate anti-TNF-GRM ADC inhibited inflammatory responses with minimal effect on systemic GC biomarkers. In addition, in a mouse model of collagen-induced arthritis, single-dose administration of the ADC, delivered at disease onset, was able to completely inhibit arthritis for greater than 30 days, whereas an anti-TNF monoclonal antibody only partially inhibited disease. ADC treatment at the peak of disease was also able to attenuate the arthritic phenotype. Clinical data for a human anti-TNF-GRM ADC (ABBV-3373) from a single ascending dose phase 1 study in healthy volunteers demonstrated antibody-like pharmacokinetic profiles and a lack of impact on serum cortisol concentrations at predicted therapeutic doses. These data suggest that an anti-TNF-GRM ADC may provide improved efficacy beyond anti-TNF alone in immune mediated diseases while minimizing systemic side effects associated with standard GC treatment.

Anti-inflammatory effect of echinacoside in collagen-induced arthritis via Nrf2/Drp1 pathway.

Oxidative damage plays an important role in the progression of rheumatoid arthritis (RA). Emerging research evidence suggests that natural antioxidants may effectively ameliorate this disease. To investigate the therapeutic effect of echinacoside (ECH) in a collagen-induced arthritis (CIA) mouse model and thus elucidate the underlying molecular mechanism in RA. Collagen-induced arthritis mice were intraperitoneally administered 1% dimethyl sulfoxide (DMSO) (control) or 0.6 mg of ECH every other day for 1 month. Arthritis scores and the number of affected paws were assessed. On day 60, mice were euthanized, synovial tissue specimens were obtained, and serum interleukin (IL)-6 and IL-1â expression levels were measured. Mitochondrial morphologies, reactive oxygen species (ROS) content, expression of dynamin-related protein 1 (Drp1), IL-6, nod-like receptor protein 3 (NLRP3), kelch-like ECH-associated protein 1 (Keap1), and nuclear factor-erythroid-2-related factor 2 (Nrf2) contents in synovium were analyzed and compared between DMSOand ECH-treated CIA mice. Following ECH treatment, mitochondria of CIA-induced mice were found to be elongated, while their arthritis scores, inflammation and the number of affected paws, and the expression levels of Drp1, NLRP3, IL-6, ROS, and Keap1 were all found to be significantly reduced. Conversely, the level of antioxidant factor Nrf2 was found to be elevated. Further, mitochondrial fission was found to be inhibited in synovial tissues. Our findings validate the therapeutic efficacy of ECH in the CIA mouse model. Echinacoside may suppress oxidative stress and inhibit inflammation by regulating the Nrf2/Drp1 pathway, thus supporting its utility in the treatment of RA.

Vigeo attenuates cartilage and bone destruction in a collagen‑induced arthritis mouse model by reducing production of pro‑inflammatory cytokines.

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.

Human embryonic stem cell–derived mesenchymal stromal cells suppress inflammation in mouse models of rheumatoid arthritis and lung fibrosis by regulating T-cell function

Background aimsRheumatoid arthritis (RA) is characterized by an overactive immune system, with limited treatment options beyond immunosuppressive drugs or biological response modifiers. Human embryonic stem cell–derived mesenchymal stromal cells (hESC-MSCs) represent a novel alternative, possessing diverse immunomodulatory effects. In this study, we aimed to elucidate the therapeutic effects and underlying mechanisms of hESC-MSCs in treating RA. MethodsMSC-like cells were differentiated from hESC (hESC-MSCs) and cultured in vitro. Cell proliferation was assessed using Cell Counting Kit-8 assay and Ki-67 staining. Flow cytometry was used to analyze cell surface markers, T-cell proliferation and immune cell infiltration. The collagen-induced arthritis (CIA) mouse model and bleomycin-induced model of lung fibrosis (BLE) were established and treated with hESC-MSCs intravenously for in vivo assessment. Pathological analyses, reverse transcription-quantitative polymerase chain reaction and Western blotting were conducted to evaluate the efficacy of hESC-MSCs treatment. ResultsIntravenous transplantation of hESC-MSCs effectively reduced inflammation in CIA mice in this study. Furthermore, hESC-MSC administration enhanced regulatory T cell infiltration and activation. Additional findings suggest that hESC-MSCs may reduce lung fibrosis in BLE mouse models, indicating their potential to mitigate complications associated with RA progression. In vitro experiments revealed a significant inhibition of T-cell activation and proliferation during co-culture with hESC-MSCs. In addition, hESC-MSCs demonstrated enhanced proliferative capacity compared with traditional primary MSCs. ConclusionsTransplantation of hESC-MSCs represents a promising therapeutic strategy for RA, potentially regulating T-cell proliferation and differentiation.

Structure-Guided Elaboration of a Fragment-Like Hit into an Orally Efficacious Leukotriene A4 Hydrolase Inhibitor.

Leukotriene A4 hydrolase (LTA4H) is the final and rate-limiting enzyme in the biosynthesis of pro-inflammatory leukotriene B4 (LTB4). Preclinical studies have provided strong evidence that LTA4H is an attractive drug target for the treatment of chronic inflammatory diseases. Here, we describe the transformation of compound 2, a fragment-like hit, into the potent inhibitor of LTA4H 3. Our strategy involved two key steps. First, we aimed to increase the polarity of fragment 2 to improve its drug-likeness, particularly its solubility, while preserving both its promising potency and low molecular weight. Second, we utilized structural information and incorporated a basic amino function, which allowed for the formation of an essential hydrogen bond with Q136 of LTA4H and consequently enhanced the potency. Compound 3 exhibited exceptional selectivity and showed oral efficacy in a KRN passive serum-induced arthritis model in mice. The anticipated human dose to achieve 90% target engagement at the trough concentration was determined to be 40 mg administered once daily.

Therapeutic Effects of IL-1RA, M2 Cells, and Their Synergistic Impact on a Mouse Model of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a type of autoimmune disease that results in chronic inflammation of the joint synovial tissue, leading to joint damage and significant disability. Despite ongoing research, the exact cause of RA remains unclear, and current treatments have limitations. This study explores the potential of utilizing interleukin-1 receptor antagonist (IL-1RA) and anti-inflammatory macrophages polarized in the vicinity of the supernatant from allogeneic mesenchymal stem cells (MSCs) as a novel therapeutic approach for RA. An expression cassette containing the IL-1RA gene was constructed and expressed in E. coli BL21. The resulting protein was purified and stabilized for use in in vivo experiments. Bone marrow MSCs were isolated and used to produce anti-inflammatory M2 macrophages from the isolated peripheral blood monocytes. The macrophages were then used to treat mice with RA induced by collagen type II. The combination of IL-1RA and M2 macrophages improved clinical and histopathological symptoms of the disease, reduced levels of inflammatory factors, and modulated the immune system in the treated mouse groups. The results showed that this combinatory therapy had a synergistic effect for RA treatment. The simultaneous use of IL-1RA and M2 cells could be a promising approach for the treatment of RA. This combinatory therapy has the potential to improve the disease and decrease the severity of inflammation in patients with RA.

Lack of Syndecan-1 promotes the pathogenesis of experimental rheumatoid arthritis.

Syndecan-1 (Sdc-1), a transmembrane heparan sulfate protein, is implicated in several pathophysiological processes including rheumatoid arthritis (RA). The exact role of Syndican-1 in this autoimmune disease is still undetermined. This study explores the involvement level of Sdc-1 in the development of RA in a collagen II-induced arthritis mice model. RA was induced in two mice strains (wild-type BALB/c group and Sdc-1 knockout) by collagen II. Mice underwent regular clinical observations and scoring. After sacrifice, leg biopsies were taken from mice for histological examination, using a variety of stains. In addition, proteins were extracted, and molecular assessment of TNF-α was performed using the western blot technique. In the Sdc-1 knockout group, clinical scoring results showed a significantly more severe experimental RA; histology showed a significant increase in bone erosion, cartilage destruction, inflammation, and less granulated mast cells than the wild-type. In addition, molecular assessment of TNF-α showed more increase in expression in the Sdc-1 knockout models compared to the wild-type. Data suggest that lack of Sdc-1 enhances the inflammatory characteristics in RA. However, more molecular studies and investigations are needed to determine its exact role and possible mechanisms involved.

Active immunotherapy for C5a-mediated inflammation using adjuvant-free self-assembled peptide nanofibers

The terminal protein in the complement cascade C5a is a potent inflammatory molecule and chemoattractant that is involved in the pathology of multiple inflammatory diseases including sepsis and arthritis, making it a promising protein to target with immunotherapies. Active immunotherapies, in which patients are immunized against problematic self-molecules and generate therapeutic antibodies as a result, have received increasing interest as an alternative to traditional monoclonal antibody treatments. In previous work, we have designed supramolecular self-assembling peptide nanofibers as active immunotherapies with defined combinations of B- and T-cell epitopes. Herein, the self-assembling peptide Q11 platform was employed to generate a C5a-targeting active immunotherapy. Two of three predicted B-cell epitope peptides from C5a were found to be immunogenic when displayed within Q11 nanofibers, and the nanofibers were capable of reducing C5a serum concentrations following immunization. Contrastingly, C5a's precursor protein C5 maintained its original concentration, promising to minimize side effects heretofore associated with C5-targeted therapies. Immunization protected mice against an LPS-challenge model of sepsis, and it reduced clinical severity in a model of collagen-antibody induced arthritis. Together, this work indicates the potential for targeting terminal complement proteins with active immunotherapies by leveraging the immunogenicity of self-assembled peptide nanomaterials. Statement of significanceChronic inflammatory diseases such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease are currently treated primarily with monoclonal antibodies against key inflammatory mediators. While helpful for many patients, they have high non-response rates, are costly, and commonly fail as anti-drug antibodies are raised by the patient. The approach we describe here explores a fundamentally different treatment paradigm: raising therapeutic antibody responses with an active immunotherapy.We employ innovative supramolecular peptide nanomaterials to elicit neutralizing antibody responses against complement component C5a and demonstrate therapeutic efficacy in preclinical mouse models of sepsis and rheumatoid arthritis. The strategy reported may represent a potential alternative to monoclonal antibody therapies.

De Novo Design of a Highly Stable Ratiometric Probe for Long-Term Continuous Imaging of Endogenous HClO Burst.

Long-term continuous imaging of endogenous HClO burst is of great importance for the elucidation of various physiological or pathological processes. However, most of the currently reported HClO probes have failed to achieve this goal due to their insufficient photobleaching resistance under a laser source. Herein, a highly stable ratiometric probe, HFTC-HClO 1, which is capable of continuously monitoring endogenous HClO burst over a long period of time, has been judiciously developed. Briefly, the de novo development of HFTC-HClO 1 mainly involved three main steps: (1) novel coumarins (HFTC 1-5) were designed and synthesized; (2) the most stable scaffold, HFTC 3, was selected through dye screening and cell imaging validation; and (3) based on HFTC 3, three candidate HClO probes were constructed, and HFTC-HClO 1 was finally selected due to its superior sensing properties toward HClO. Furthermore, HFTC-HClO 1 can quantitatively measure HClO levels in various real samples with excellent recovery (>90.4%), and the use of HFTC-HClO 1-coated test strips for qualitative analysis of HClO in real samples was also achieved. In addition, the application of HFTC-HClO 1 for long-term continuous monitoring of intracellular HClO burst was successfully demonstrated. Significantly, HFTC-HClO 1 was able to visualize HClO generated in the rheumatoid arthritis mouse model.

NJK14047 inhibition of p38 MAPK ameliorates inflammatory immune diseases by suppressing T cell differentiation

p38 MAPK has been implicated in the pathogenesis of rheumatoid arthritis and psoriasis. To assess the therapeutic efficacy of the p38 MAPK inhibitor NJK14047 in the treatment of rheumatoid arthritis and psoriasis, we developed mouse models of collagen-induced rheumatoid arthritis (CIA) and imiquimod-induced psoriasis (IIP). NJK14047 was found to suppress arthritis development and psoriasis symptoms and also suppressed histopathological changes induced by CIA and IIP. Furthermore, we established that CIA and IIP evoked increases in the mRNA expression levels of Th1/Th17 inflammatory cytokines in the joints and skin, which was again suppressed by NJK14047. NJK14047 reversed the enlargement of spleens induced by CIA and IIP as well as increases in the levels of inflammatory cytokine in spleens following induction by CIA and IIP. In human SW982 synovial cells, NJK14047 was found to suppress lipopolysaccharide-induced increases in the mRNA expression of proinflammatory cytokines. NJK14047 inhibition of p38 MAPK suppressed the differentiation of naïve T cells to Th17 and Th1 cells. Our findings in this study provide convincing evidence indicating the therapeutic efficacy of the p38 MAPK inhibitor NJK14047 against CIA and IIP, which we speculate could be associated with the suppression on T-cell differentiation.

Anti-inflammatory and anti-arthritic potential of Coagulansin-A: in vitro and in vivo studies.

The current work was designed to evaluate the anti-inflammatory and anti-arthritic potential of Coagulansin-A (Coag-A) using mouse macrophages and arthritic mice. In the LPS-induced RAW 264.7 cells, the effects of Coag-A on the release of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory cytokines were analyzed. In addition, the mediators involved in the nuclear factor-kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways were evaluated by the RT-qPCR and western blotting. Coag-A did not show significant cytotoxicity in the RAW 264.7 cells in the tested concentration range (1-100 µM). Coag-A significantly inhibited the production of NO, ROS, and key pro-inflammatory cytokines. The anti-inflammatory effects of Coag-A might be through inhibiting the NF-κB pathway and activating the Nrf2 pathway. In the arthritic mouse models, behavioral studies and radiological and histological analyses were performed. We found that the i.p. injection of Coag-A dose-dependently (1-10 mg/kg) reduced the Carrageenan-induced acute inflammation in the mice. In Complete Freund's Reagent-induced arthritic mouse model, Coag-A (10 mg/kg) showed significant anti-inflammatory and anti-arthritic effects in terms of the arthritic index, hematological parameters, and synovium inflammation. After the Coag-A treatment, the bone and tissue damage was ameliorated significantly in the arthritic mice. Moreover, immunohistochemistry of mouse paw tissues revealed a significant reduction in the expression of pro-inflammatory cytokines in the NF-κB pathway, confirming Coag-A's therapeutic potential and mechanism.

Biomimetic and inflammation-targeted nanoparticles for rheumatoid arthritis therapy via M1-macrophages apoptosis and polarization

M1 macrophages enrich in rheumatoid arthritis (RA) joints and contribute to persistent progression of inflammation and destruction. Their apoptosis and polarization toward M2 phenotype play crucial roles in anti-inflammation. Herein, we developed three kinds of biomimetic nanoparticles (NPs) derived from different cells for dual-targeting to inflamed site and M1 macrophages. These NPs were aimed to induce M1 macrophages apoptosis and re-polarization for efficient RA therapy via dually targeting drug delivery to inflamed joints and M1 macrophages. Results demonstrated that the NPs had a massive accumulation at inflamed site and high internalization efficiency in M1 macrophages. After loading methotrexate, the NPs substantially suppressed the viability of activated macrophages and the expression of pro-inflammatory cytokines. Furthermore, they dramatically promoted the expression of anti-inflammatory cytokines, and induced M1-to-M2 transition of macrophages. In an adjuvant-induced arthritis mouse model, the NPs efficiently reduced the number of inflammatory macrophages, secretion of pro-inflammatory cytokines and destruction of cartilage or bone tissues. Additionally, the swelling of paw and ankle joint was significantly alleviated by the NPs after 17 days treatment, especially the activated macrophage-derived NPs. The findings highlight the potential of NPs with dual-targeting ability in the treatment of RA by apoptosis and re-polarization of M1 macrophages.

Sulfasalazine promotes ferroptosis through AKT-ERK1/2 and P53-SLC7A11 in rheumatoid arthritis.

Ferroptosis has been reported to play a role in rheumatoid arthritis (RA). Sulfasalazine, a common clinical treatment for ankylosing spondylitis, also exerts pathological influence on the progression of rheumatoid arthritis including the induced ferroptosis of fibroblast-like synoviocytes (FLSs), which result in the perturbated downstream signaling and the development of RA. The aim of this study was to investigate the underlying mechanism so as to provide novel insight for the treatment of RA. CCK-8 and Western blotting were used to assess the effect of sulfasalazine on FLSs. A collagen-induced arthritis mouse model was constructed by the injection of collagen and Freund's adjuvant, and then, mice were treated with sulfasalazine from day 21 after modeling. The synovium was extracted and ferroptosis was assessed by Western blotting and immunofluorescence staining. The results revealed that sulfasalazine promotes ferroptosis. Compared with the control group, the expression levels of ferroptosis-related proteins such as glutathione peroxidase 4, ferritin heavy chain 1, and solute carrier family 7, member 11 (SLC7A11) were lower in the experimental group. Furthermore, deferoxamine inhibited ferroptosis induced by sulfasalazine. Sulfasalazine-promoted ferroptosis was related to a decrease in ERK1/2 and the increase of P53. Sulfasalazine promoted ferroptosis of FLSs in rheumatoid arthritis, and the PI3K-AKT-ERK1/2 pathway and P53-SLC7A11 pathway play an important role in this process.

Fibroblast-like synoviocytes-derived exosomal circFTO deteriorates rheumatoid arthritis by enhancing N6-methyladenosine modification of SOX9 in chondrocytes

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease that causes disability worldwide. Exosomes released by fibroblast-like synoviocytes in RA (RA-FLSs-Exos) play a role in the development of RA, and circular RNAs (circRNAs) are important for RA progression. This study aimed to investigate the molecular mechanisms underlying the effects of RA-FLSs-Exos in RA and identify the potential pathway responsible for these effects.MethodsWe initially conducted microarray analysis to identify dysregulated circRNAs in exosomes associated with RA. We then co-cultured isolated RA-FLSs-Exos with chondrocytes to examine their role in RA. In vivo experiments were performed using collagen-induced arthritis mouse models, and circFTO knockdown was achieved through intra-articular injection of AAV5 vectors.ResultsOur findings revealed increased expression of circFTO in both RA-FLSs-Exos and synovial tissues from patients with RA. Exosomal circFTO hindered chondrocyte proliferation, migration, and anabolism while promoting apoptosis and catabolism. Mechanistically, we discovered that circFTO facilitates the formation of methyltransferases complex to suppress SRY-related high-mobility group box 9 (SOX9) expression with assistance from YTH domain family 2 (YTHDF2) through an m6A-dependent mechanism. Furthermore, inhibition of circFTO improved symptoms of RA in vivo.ConclusionTaken together, our study demonstrates that exosomal circFTO derived from FLSs contributes to the progression of RA by targeting SOX9. These findings highlight a promising target for treating RA.

Emodin promotes the recovery of rheumatoid arthritis by regulating the crosstalk between macrophage subsets and synovial fibroblast subsets.

To study the relationships among emodin, synovial fibroblasts (FLSs), and macrophages (STMs) to provide guidance for the use of emodin in rheumatoid arthritis (RA) treatment. RA clinical samples from patients with different pathological processes were collected, and the correlations between the subsets of FLSs and STMs and pathological processes were analyzed via flow cytometry. Invitro experimental methods such as enzyme linked immunosorbent assay (ELISA), Western blotting, Transwell assays, CCK-8 assays and cell coculture were used to assess cell proliferation, migration and secretion of inflammatory factors. A collagen-induced arthritis mouse model was constructed to investigate the therapeutic potential of emodin in RA by flow cytometry, micro-CT and staining. Unique subsets of FLSs and STMs, namely, FAPα+ THY1- FLSs, FAPα+ THY1+ FLSs, and MerTKpos TREM2high STMs, were identified in synovial tissues from RA patients. The number of MerTKpos TREM2high STMs was negatively correlated with the degree of damage in RA, while the number of FAPα+ THY1- FLSs was positively correlated with damage. On the one hand, emodin promoted the aggregation of MerTKposTREM2high STMs. Moreover, MerTKpos TREM2high STM-mediated secretion of exosomes was promoted, which can inhibit the secretion of pro-inflammatory factors by FAPα+ THY1+ FLSs and promote the secretion of anti-inflammatory factors by FAPα+ THY1+ FLSs, thereby inhibiting FAPα+ THY1- FLS proliferation and migration, improving the local immune microenvironment, and inhibiting RA damage. Emodin was shown to regulate the aggregation of STM subsets and exosome secretion, affecting the secretion, proliferation and migration of inflammatory factors in FLS subsets, and ultimately achieving good therapeutic efficacy in RA patients, suggesting that it has important clinical value.