Mouse Model Of Arthritis Research Articles

Oxymatrine ameliorates rheumatoid arthritis by regulation of Tfr/Tfh cell balance via the TLR9-MyD88-STAT3 signaling pathway.

Oxymatrine (OMT) is one of the authentic Chinese herbal medicines which has rich and complex active ingredients. however,the relevant potential targets of oxymatrine on rheumatoid arthritis and the mechanism remains unreported. The aim of this study was to determine the regulation of oxymatrine on rheumatoid arthritis using a collagen-induced arthritis (CIA) mice models and blood samples from RA patients. Our results indicated that Tfr cells in RA patients express low levels of Blimp-1 and CTLA-4. Oxymatrine treatment of CIA mice alleviated joint swelling, reduced the arthritis score, and improved joint damage. While flow cytometry results showed that oxymatrine treatment reduced Tfh cells and B cells, and increased Tfr cells in the spleen of CIA mice. In addition, oxymatrine treatment significantly down-regulated the expression of TLR9（Toll-like Receptors 9), IL-21, MyD88, STAT3, p-STAT3, and CXCR5 in the synovial tissues of CIA mice, and up-regulated the expression of Foxp3, Blimp-1, and CTLA-4. Oxymatrine can alleviate rheumatoid arthritis by regulating the TLR9-MyD88-STAT3 signaling pathway to maintain immune balance between Tfr-Tfh cells. © 2023 Society of Chemical Industry.

Signal peptide mimicry primes Sec61 for client-selective inhibition

Preventing the biogenesis of disease-relevant proteins is an attractive therapeutic strategy, but attempts to target essential protein biogenesis factors have been hampered by excessive toxicity. Here we describe KZR-8445, a cyclic depsipeptide that targets the Sec61 translocon and selectively disrupts secretory and membrane protein biogenesis in a signal peptide-dependent manner. KZR-8445 potently inhibits the secretion of pro-inflammatory cytokines in primary immune cells and is highly efficacious in a mouse model of rheumatoid arthritis. A cryogenic electron microscopy structure reveals that KZR-8445 occupies the fully opened Se61 lateral gate and blocks access to the lumenal plug domain. KZR-8445 binding stabilizes the lateral gate helices in a manner that traps select signal peptides in the Sec61 channel and prevents their movement into the lipid bilayer. Our results establish a framework for the structure-guided discovery of novel therapeutics that selectively modulate Sec61-mediated protein biogenesis.

Identification and validation of metabolism-related genes signature and immune infiltration landscape of rheumatoid arthritis based on machine learning.

Rheumatoid arthritis (RA) causes irreversible joint damage, but the pathogenesis is unknown. Therefore, it is crucial to identify diagnostic biomarkers of RA metabolism-related genes (MRGs). This study obtained transcriptome data from healthy individuals (HC) and RA patients from the GEO database. Weighted gene correlation network analysis (WGCNA), the least absolute shrinkage and selection operator (LASSO), and random forest (RF) algorithms were adopted to identify the diagnostic feature biomarker for RA. In addition, biomarkers were verified by qRT-PCR and Western blot analysis. We established a mouse model of collagen-induced arthritis (CIA), which was confirmed by HE staining and bone structure micro-CT analysis, and then further verified the biomarkers by immunofluorescence. In vitro NMR analysis was used to analyze and identify possible metabolites. The correlation of diagnostic feature biomarkers and immune cells was performed using the Spearman-rank correlation algorithm. In this study, a total of 434 DE-MRGs were identified. GO and KEGG enrichment analysis indicated that the DE-MRGs were significantly enriched in small molecules, catabolic process, purine metabolism, carbon metabolism, and inositol phosphate metabolism. AKR1C3, MCEE, POLE4, and PFKM were identified through WGCNA, LASSO, and RF algorithms. The nomogram result should have a significant diagnostic capacity of four biomarkers in RA. Immune infiltration landscape analysis revealed a significant difference in immune cells between HC and RA groups. Our findings suggest that AKR1C3, MCEE, POLE4, and PFKM were identified as potential diagnostic feature biomarkers associated with RA's immune cell infiltrations, providing a new perspective for future research and clinical management of RA.

Effects of rIL2/anti-IL2 antibody complex on chikungunya virus-induced chronic arthritis in a mouse model

Chikungunya virus (CHIKV) is characterized by disabling joint pain that can cause persistent arthritis in approximately one-fourth of patients. Currently, no standard treatments are available for chronic CHIKV arthritis. Our preliminary data suggest that decreases in interleukin-2 (IL2) levels and regulatory T cell (Treg) function may play a role in CHIKV arthritis pathogenesis. Low-dose IL2-based therapies for autoimmune diseases have been shown to up-regulate Tregs, and complexing IL2 with anti-IL2 antibodies can prolong the half-life of IL2. A mouse model for post-CHIKV arthritis was used to test the effects of recombinant IL2 (rIL2), an anti-IL2 monoclonal antibody (mAb), and the complex on tarsal joint inflammation, peripheral IL2 levels, Tregs, CD4 + effector T cells (Teff), and histological disease scoring. The complex treatment resulted in the highest levels of IL2 and Tregs, but also increased Teffs, and therefore did not significantly reduce inflammation or disease scores. However, the antibody group, which had moderately increased levels of IL2 and activated Tregs, resulted in a decreased average disease score. These results suggest the rIL2/anti-IL2 complex stimulates both Tregs and Teffs in post-CHIKV arthritis, while the anti-IL2 mAb increases IL2 availability enough to shift the immune environment towards a tolerogenic one.

BMP-2 Genome-Edited Human MSCs Protect against Cartilage Degeneration via Suppression of IL-34 in Collagen-Induced Arthritis.

Even though the regenerative potential of mesenchymal stem cells (MSCs) has been extensively studied, there is a debate regarding their minimal therapeutic properties. Bone morphogenetic proteins (BMP) are involved in cartilage metabolism, chondrogenesis, and bone healing. In this study, we aimed to analyze the role of genome-edited BMP-2 overexpressing amniotic mesenchymal stem cells (AMMs) in a mouse model of collagen-induced arthritis (CIA). The BMP-2 gene was synthesized and inserted into AMMs using transcription activator-like effector nucleases (TALENs), and BMP-2-overexpressing AMMs (AMM/B) were sorted and characterized using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The co-culture of AMM/B with tumor necrosis factor (TNF)-α-treated synovial fibroblasts significantly decreased the levels of interleukin (IL)-34. The therapeutic properties of AMM/B were evaluated using the CIA mouse model. The injection of AMM/B attenuated CIA progression and inhibited T helper (Th)17 cell activation in CIA mice. In addition, the AMM/B injection increased proteoglycan expression in cartilage and decreased the infiltration of inflammatory cells and factors, including IL-1β, TNF-α, cyclooxygenase (COX)-2, and Nuclear factor kappa B (NF-kB) in the joint tissues. Therefore, editing the BMP-2 genome in MSCs might be an alternative strategy to enhance their therapeutic potential for treating cartilage degeneration in arthritic joints.

CXCR3 antagonist NBI-74330 mitigates joint inflammation in Collagen-Induced arthritis model in DBA/1J mice.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by uncontrolled synovial proliferation, pannus formation, cartilage injury, and bone destruction. We used the CXCR3-specific antagonist NBI-74330 to block T-cell-mediated signaling in a DBA/1J mouse model of collagen-induced arthritis (CIA). After CIA induction, DBA/1J mice were treated with NBI-74330 (100mg/kg) daily from day 21 until day 34 and evaluated for arthritic score and histopathological changes. Furthermore, using flow cytometry, we investigated the effects of NBI-74330 on Th1 (IFN-γ, TNF-α, T-bet, STAT4, Notch-3, and RANKL), Th17 (IL-21, IL-17A, STAT3, and RORγt), and Th22 (IL-22) cells in splenic CD4+ and CXCR3+T-cells. We also used RT-PCR to assess the effect of mRNA levels of IFN-γ, TNF-α, T-bet, RANKL, IL-17A, RORγt, and IL-22 in knee tissues. The IFN-γ, TNF-α, and IL-17A serum protein levels were measured using ELISA. Compared to vehicle-treated CIA mice, the severity of arthritic scores and histological severity of inflammation decreased significantly in NBI-74330-treated CIA mice. Moreover, compared to vehicle-treated CIA mice, the percentages of CD4+IFN-γ+, CD4+TNF-α+, CD4+T-bet+, CD4+STAT4+, CD4+Notch-3+, CXCR3+IFN-γ+, CXCR3+TNF-α+, CXCR3+T-bet+, CXCR3+STAT4+, CXCR3+Notch-3+, CD4+RANKL+, CD4+IL-21+, CD4+IL-17A+, CD4+STAT3+, CD4+RORγt+, and CD4+IL-22+ cells decreased in NBI-74330-treated CIA mice. Furthermore, NBI-74330-treatment downregulated IFN-γ, TNF-α, T-bet, RANKL, STAT3, IL-17A, RORγt, and IL-22 mRNA levels. Serum IFN-γ, TNF-α, and IL-17A levels were significantly lower in NBI-74330-treated CIA mice than in vehicle-treated CIA mice. This study demonstrates the antiarthritic effects of NBI-74330 in CIA mice. Therefore, these data suggest that NBI-74330 could be considered a potential RA treatment.

Abstract 575: Impact Of Resident Macrophages On Fibrosis And Lymphatic Growth During Autoimmune Valvular Carditis

Rheumatic diseases are associated with increased cardiovascular disease and the mitral valve (MV) is one of the tissues most commonly affected. Valve disease prevalence continues to rise yet the mechanisms driving autoimmune valvular carditis are incompletely understood, limiting treatment options. Our team has previously demonstrated a role for macrophages in promoting MV disease in the K/B.g7 mouse model of autoantibody-induced arthritis and valvular carditis. To further characterize the MV macrophage populations, we conducted single cell RNA sequencing of healthy (B.g7) and inflamed (K/B.g7) MVs. Analysis revealed multiple macrophage populations including Ccr2 + Bhlhe40 + recruited, pro-inflammatory macrophages and Mrc1 + Cd63 + resident macrophages, which we further validated by flow cytometry. These findings raised new questions regarding which subset(s) of macrophages influence disease progression and how. Within the resident population, we identified a subset of Lyve1 + Folr2 + macrophages. Immunostaining demonstrated that this macrophage subset localizes along the valve endothelium and near lymphatic vessels that we have recently demonstrated emerge in inflamed valves and promote valve disease. Importantly, we also found LYVE1+ macrophages co-localized with lymphatics in human MVs. Prior studies demonstrate that LYVE1+ macrophages are important regulators of vessel growth and extracellular matrix regulation. Thus, we hypothesized that LYVE1+ resident macrophages promote MV disease by augmenting lymphatic growth and contributing to changes in extracellular matrix. To understand the potential functions of these cells, we depleted Lyve1 -expressing macrophages in vivo by crossing Lyve1 -Cre mice with the Csf1r -floxed mice. We found that valves from LYVE1+ macrophage-depleted non-inflamed mice have increased collagen deposition, suggesting these macrophages are important for restraining extracellular matrix deposition. Studies are underway to determine if these resident macrophages promote fibrosis and lymphatic growth in the pro-inflammatory environment of the K/B.g7 model. Outcomes from these studies will have important implications for other cardiovascular and fibrotic diseases.

Aneugenic and clastogenic alterations in the DBA/IJ mouse model of rheumatoid arthritis treated with rituximab, an anti-CD20 antibody.

Rheumatoid arthritis (RA), an autoimmune disorder in which the immune system attacks healthy cells, is associated with elevated risk of lymphoma. Rituximab, a treatment for non-Hodgkin's lymphoma, has been approved as a treatment for RA. We studied the effects of rituximab on chromosomal stability in collagen-induced arthritis DBA/1J animal models. Micronucleus levels were increased in the mouse models, mainly due to chromosome loss, as detected by fluorescence in situ hybridization; rituximab-treated arthritic mice had significantly less micronucleus formation. Serum 8-hydroxydeoxyguanosine, a DNA oxidative stress marker, was increased in the mice models but reduced following rituximab administration.

Magnoflorine Ameliorates Collagen-Induced Arthritis by Suppressing the Inflammation Response via the NF-κB/MAPK Signaling Pathways.

Magnoflorine (Mag) has been reported to have anxiolytics, anti-cancer, and anti-inflammatory properties. In this study, we aim to investigate the effects of Mag on the rheumatoid arthritis (RA) and explore the underlying mechanism using a collagen-induced arthritis (CIA) mouse model and a lipopolysaccharide (LPS)-stimulated macrophage inflammation model. The in vivo effects of Mag on CIA were studied by inducing CIA in a mouse model using DBA/1J mice followed by treatment with vehicle, methotrexate (MTX, 1 mg/kg/d), and Mag (5 mg/kg/d, 10 mg/kg/d, and 20 mg/kg/d), and the in vitro effects of Mag on macrophages were examined by stimulation of RAW264.7 cells line and peritoneal macrophages (PMs) by LPS in the presence of different concentrations of Mag. Network pharmacology and molecular docking was then performed to predict the the binding ability between Mag and its targets. Inflammatory mediators were assayed by quantitative real-time PCR and enzyme linked immunosorbent assay (ELISA). Signaling pathway changes were subsequently determined by Western blotting and immunohistochemistry (IHC). In vivo experiments demonstrated that Mag decreased arthritis severity scores, joints destruction, and macrophages infiltration into the synovial tissues of the CIA mice. Network pharmacology analysis revealed that Mag interacted with TNF-α, IL-6, IL-1β, and MCP-1. Consistent with this, analysis of the serum, synovial tissue of the CIA mice, and the supernatant of the cultured RAW264.7 cells and PMs showed that Mag suppressed the expression of TNF-α, IL-6, IL-1β, MCP-1, iNOS, and IFN-β. Furthermore, Mag attenuated the phosphorylation of p65, IκBα, ERK, JNK, and p38 MAPKs in the synovial tissues of the CIA mice and LPS-stimulated RAW 264.7 cells. Mag may exert anti-arthritic and anti-inflammatory effects by inhibiting the activation of NF-κB and MAPK signaling pathways.

Ultrasound-driven BaTiO 3 nanorobots patching immunologic barrier to cure chronic rheumatoid arthritis

The disruption and reconstruction of the TREM2⁺ tissue resident macrophage (TRM) barrier on the surface of synovial lining play a key role in the activation and "remission" of rheumatoid arthritis (RA), which engender the prediction of this immunologic barrier as a potential driver for the achievement of "cure" in RA. However, strategies to promote the reconstruction of this barrier have not been reported, and the effect of patching this barrier remains unidentified. On the other hand, appropriate piezoelectric stimulation can reprogram macrophages, which has never been exerted on this barrier TRM yet. Herein, we design piezoelectric tetragonal BaTiO₃ (BTO) ultrasound-driven nanorobots (USNRs) by the solvothermal synthesis method, which demonstrates satisfactory electro-mechanical conversion effects, paving the way to generate controllable electrical stimulation under ultrasound to reprogram the barrier TRM by minimally invasive injection into joint cavity. It is demonstrated that the immunologic barrier could be patched by this USNR effectively, thereby eliminating the hyperplasia of vessels and nerves (HVN) and synovitis. Additionally, TREM2 deficiency serum-transfected arthritis (STA) mice models are applied and proved the indispensable role of TREM2 in RA curing mediated by USNR. In all, our work is an interesting and important exploration to expand the classical tetragonal BTO nanoparticles in the treatment of autoimmune diseases, providing a new idea and direction for the biomedical application of piezoelectric ceramics.

HIF-1α dependent RhoA as a novel therapeutic target to regulate rheumatoid arthritis fibroblast-like synoviocytes migration in vitro and in vivo.

The purpose of this work is to investigate how the Rho family of GTPases A (RhoA) mediates the pathogenesis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). The expression of RhoA in the synovial tissues of RA and Healthy people (Control) was detected using immunohistochemistry methods. The expression of RhoA and hypoxia-inducible factor-1α (HIF-1α) is inhibited by small interfering RNAs (siRNAs). The inhibition effect on RA-FLS migration was further investigated. The protein expression level of HIF-1α, RhoA, focal adhesion kinase (FAK), and myosin light chain (MLC) was also analysed using western blotting (WB). DBA1 mice were immunised with the mixture of bovine type II collagen and Freund's adjuvant to establish collagen induced arthritis (CIA) mouse model. Lip-siRhoA is administered through joint injection every two days. Micro-computed tomography (micro-CT) was used to detect mouse ankle joint destruction and evaluate the bone loss of the periarticular side. Destruction of the ankle articular cartilage was tested by histology. Expressions of P-RhoA, P-FAK and P-MLC in the ankle joint was detected by immunohistochemistry assay. The expression level of RhoA in the synovial tissues of RA patients was significantly higher than that in control group. Hypoxia was able to up-regulate the expression of RhoA. Whereas, HIF-1α siRNA (siHIF-1α) could down-regulate the expression of RhoA. Additionally, both of siHIF-1α and RhoA siRNA (siRhoA) delivered by liposome (Lip-siHIF-1α and Lip-siRhoA) were found to suppress FAK and MLC phosphorylation in vitro. In CIA mouse model, Lip-siRhoA was demonstrated to ameliorate the destruction of ankle joint and reduce the severity of ankle joint cartilage damage by micro-CT and histological staining, respectively. Therefore, inhibition of FLS cell migration can protect articular bone from destruction. Furthermore, the expression of P-RhoA, P-FAK and P-MLC was evaluated and found to be down-regulated by Lip-siRhoA in vivo. The results demonstrated that under hypoxic environment, HIF-1α dependent RhoA pathway played an important role on cytoskeleton remodelling and RA-FLS migration. Through down-regulating RhoA expression, it could effectively treat RA in vitro and in vivo. Our study provides new evidence for the potential clinical application of RhoA as a candidate for the treatment of RA.

Lonicerin alleviates the progression of experimental rheumatoid arthritis by downregulating M1 macrophages through the NF-κB signaling pathway.

The present study aimed to evaluate anti-rheumatoid arthritis (RA) effect of Lonicerin (LON), a safe compound with anti-inflammatory and immunomodulatory properties. Nevertheless, the exact role of LON in RA remains elusive. In this test, the anti-RA effect of LON was evaluated in collagen-induced arthritis (CIA) mouse model. Relevant parameters were measured during the experiment; ankle tissue and serum were collected at the end of the experiment for radiology, histopathology, and inflammation analysis. ELISA, qRT-PCR, immunofluorescence, and western blot were used to explore the effect of LON on the polarization of macrophages and related signal pathways. It was discovered that LON treatment attenuated the disease progression of CIA mice with lower paw swelling, clinical score, mobility, and inflammatory response. LON treatment significantly decreased M1 marker levels in CIA mice and LPS/IFN-γ-induced RAW264.7 cells, while slightly increasing M2 marker levels in CIA mice and IL-4-induced RAW264.7 cells. Mechanistically, LON attenuated the activation of the NF-κB signaling pathway, which contributes to M1 macrophage polarization and inflammasome activation. In addition, LON inhibited NLRP3 inflammasome activation in M1 macrophages, thereby reducing inflammation by inhibiting IL-1β and IL-18 release. These results indicated that LON might exert anti-RA effects by regulating the polarization of M1/M2 macrophage, especially by inhibiting macrophage polarization toward M1.

Fusobacterium nucleatum aggravates rheumatoid arthritis through FadA-containing outer membrane vesicles

Rheumatoid arthritis (RA) is an autoimmune disorder that has been associated with the gut microbiota. However, whether and how the gut microbiota plays a pathogenic role in RA remains unexplored. Here, we observed that Fusobacterium nucleatum is enriched in RA patients and positively associated with RA severity. F.nucleatum similarly aggravates arthritis in a mouse model of collagen-induced arthritis (CIA). F.nucleatum outer membrane vesicles (OMVs) containing the virulence determinant FadA translocate into the joints, triggering local inflammatory responses. Specifically, FadA acts on synovial macrophages, resulting in the activation of the Rab5a GTPase involved in vesicle trafficking and inflammatory pathways and YB-1, a key regulator of inflammatory mediators. OMVs containing FadA and heightened Rab5a-YB-1 expression were observed in RA patients compared with controls. These findings suggest a causal role of F.nucleatum in aggravating RA and provide promising therapeutic targets for clinically ameliorating RA.

Evaluation of 18F-FAPI-04 Imaging in Assessing the Therapeutic Response of Rheumatoid Arthritis.

Fibroblast activating protein (FAP) is highly expressed in the synovial tissues of rheumatoid arthritis (RA) patients. The aim of this study was to determine the feasibility of PET imaging with an Al[18F] F-NOTA-labeled FAP inhibitor 04(18F-FAPI-04) for the evaluation of arthritic progression and therapeutic response in experimental arthritis. Fibroblast-like synoviocytes (FLSs) were obtained from patients with RA or osteoarthritis (OA), and the relationship between 18F-FAPI-04 uptake and the inflammatory activity of RA FLSs was investigated. Collagen-induce arthritis (CIA) mice models were established and treated with methotrexate (MTX) or etanercept (ETC). Then, PET imaging was performed 24h following 18F-FAPI-04 injection. The imaging results were compared by assessing macroscopic arthritis scores and histological staining. 18F-FAPI-04 uptake was obvious in RA FLSs that characterizing FAP activation. The higher the uptake of 18F-FAPI-04, the more severity of the inflammatory phenotype in RA FLS. Furthermore, the uptake of 18F-FAPI-04 in inflamed joints could be found even before the deformity of the parental joints could be observed by histological examination. Both MTX and ETC were effective in inhibiting the progression of arthritis in CIA mice was confirmed by macroscopic, histological, and radiographic pathology scores. Importantly, 18F-FAPI-04 uptake declined accordingly in CIA models following MTX and ETC treatment. These findings suggest that PET imaging of 18F-FAPI-04 can be used to monitor treatment response in RA, and is more sensitive in disease speculation than macroscopic arthritis scoring.

Noninvasive Imaging OX40+ Activated T Cells Provides Early Warning of Rheumatoid Arthritis

PurposeThe goal of this study was to develop an imaging probe—IRDye-680RD-OX40 mAb—that can be used for noninvasive imaging and optical imaging of rheumatoid arthritis (RA). OX40/OX40 ligand (OX40L) interactions have been shown to exert potent costimulatory effects on T cell activation. Detectable change in T cell activation profiles was observed in early RA.MethodsOX40 expression pattern was analyzed by flow cytometry. N-hydroxysuccinimide (NHS) esters are used to label proteins selectively on free amino groups of OX40 monoclonal antibody (mAb). Characterization of IRDye-680RD-OX40 mAb was measured and a fluorescence spectrum gathered. Cell binding assay was also performed between activated and naïve murine T cells. Longitudinal near-infrared fluorescence (NIRF) imaging of the probe was performed on day 8, day 9, day 10, and day 11 of adjuvant-induced arthritis (AIA) mouse model. Paw thickness and body weight were compared between the OX40 mAb and IgG injection groups.ResultsNIRF imaging with IRDye-680RD-OX40 mAb revealed strong OX40-positive responses with high specificity. Flow analysis showed that OX40 was specifically expressed on the surface of T cells in RP and spleen of AIA model. The AIA group was significantly differentiated from the control group at all time points with imaging monitoring. The region of interest (ROI) was in line with ex vivo imaging and biodistribution study. This study highlights the potential utility of the OX40 NIRF imaging as a new strategy for RA prediction and T cell monitoring.ConclusionThe results provide evidence that IRDye-680RD-OX40 mAb detects organized T cells activation in early RA. The optical probe was capable of detection of RA pathogenesis. It identified transcriptional responses to RA that mediate its immune functions. Thus, it may be an ideal probe for RA imaging.Graphical

Celastrol suppresses humoral immune responses and autoimmunity by targeting the COMMD3/8 complex.

Celastrol, a bioactive molecule extracted from the Tripterygium wilfordii plant, has been shown to exhibit anti-inflammatory properties. However, its mechanism of action has not been fully elucidated. Here, we show that celastrol suppresses humoral immune responses and autoimmunity by disabling a protein complex consisting of copper metabolism MURR1 domain-containing (COMMD) 3 and COMMD8 (COMMD3/8 complex), a signaling adaptor for chemoattractant receptors. Having demonstrated the involvement of the COMMD3/8 complex in a mouse model of rheumatoid arthritis, we identified celastrol as a compound that covalently bound to and dissociated the COMMD3/8 complex. Celastrol inhibited B cell migration, reduced antibody responses, and blocked arthritis progression, recapitulating deficiency of the COMMD3/8 complex. These effects of celastrol were abolished in mice expressing a celastrol-resistant mutant of the COMMD3/8 complex. These findings establish that celastrol exerts immunosuppressive activity by targeting the COMMD3/8 complex. Our study suggests that the COMMD3/8 complex is a potentially druggable target in autoimmune diseases and points to celastrol as a lead pharmacologic candidate in this capacity.

CircRNA_17725 Promotes Macrophage Polarization towards M2 by Targeting FAM46C to Alleviate Arthritis.

Accumulating studies have implicated that circular RNAs (circRNAs) play vital roles in the pathogenesis of rheumatoid arthritis (RA). Dysregulation of macrophage polarization leads to immune homeostatic imbalance in RA. However, the altering effects and mechanisms of circRNAs on macrophages polarization and immune homeostatic balance remain largely unclear. We aimed to investigate the potential role of circRNA_17725 in RA. The high-throughput sequence was performed to identify the dysregulated circRNAs in RA. We confirmed the data by CCK-8, EdU, and Annexin V/PI staining to elucidate the proliferation and apoptosis. The expressions of M1/M2-associated markers were confirmed using real-time PCR and flow cytometry analysis. Luciferase reporter assay and RNA Binding Protein Immunoprecipitation (RIP) were used to demonstrate the underlying mechanism of circRNA_17725. The altering effect of circRNA_17725 on macrophages in vivo was evaluated using collagen-induced arthritis (CIA) mouse model. circRNA_17725 was demonstrated to be downregulated in peripheral blood mononuclear cells and CD14+ monocytes from RA cases in contrast to healthy controls. The negative association between circRNA_17725 and the disease activity indexes (CRP, ESR, and DAS28) was observed, suggesting a vital role of circRNA_17725 in RA disease activity. Besides, after a coexpression analysis based on high-input sequencing and the bioinformatics analysis in MiRanda and TargetScan databases, a circRNA_17725-miR-4668-5p-FAM46C competing endogenous RNA (ceRNA) network was hypothesized. A series of cytology experiments in vitro have implicated that circRNA_17725 could inhibit the proliferation but enhance the apoptosis of macrophages. Decreased expression of TNF-α, IL-1β, and MMP-9 were observed in the supernatant of circRNA_17725-overexpressed Raw264.7 macrophages, implicating the inhibitory effect of circRNA_17725 on macrophage inflammatory mediators. Furthermore, circRNA_17725 could promote macrophage polarization towards M2 by targeting miR-4668-5p/FAM46C as a miRNA sponge. Additionally, circRNA_17725-overexpressed macrophages alleviated arthritis and protected against joint injuries and bone destruction by inducing macrophage polarization towards M2 in collagen-induced arthritis (CIA) mice. This study has suggested that circRNA_17725 regulated macrophage proliferation, apoptosis, inflammation, and polarization by sponging miR-4668-5p and upregulating FAM46C in RA.

Photobiomodulation ameliorates inflammatory parameters in fibroblast-like synoviocytes and experimental animal models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic destructive inflammatory disease that afflicts over one percent of the world's population. Current pharmacological treatments remain relatively ineffective. In this context, photobiomodulation (PBM) is a potential resource for the treatment of RA. This study investigates investigate the anti-arthritic effects and related mechanisms of PBM on fibroblast-like synoviocytes (FLSs) from RA patients and a mouse model of collagen-induced arthritis (CIA). The RA-FLSs were irradiated with a light emitting diode (LED) at a wavelength of 610 nm for 20min, and the corresponding power intensities were 5 and 10 mW/cm2. After the LED irradiation, cell viability, proliferation, migration, and invasion assays were performed. Male DBA/1J mice were used to establish an animal model of CIA. Light stimulation with 10 mW/cm2 was applied to the ankle joints via direct contact with the skin for 40min, daily for 2 weeks. PBM significantly reduced tumor necrosis factor (TNF)-α-induced increase in proliferation, migration, and invasion in RA-FLSs, and downregulated the activation of nuclear factor-κappa B (NF-κB) and NLRP3 inflammasome by TNF-α. Moreover, PBM greatly inhibited the induction and development of CIA, resulting in the inhibition of synovial inflammation and cartilage degradation. PBM therapy decreased the serum levels of pro-inflammatory cytokines, while increasing the anti-inflammatory cytokines. PBM suppressed the translocation of NF-κB and activation of NLRP3 inflammasome in the ankle joint. Furthermore, PBM showed a more pronounced anti-arthritic effect when combined with methotrexate (MTX), a disease-modifying anti-rheumatic drug (DMARD). The results showed that the effectiveness of MTX + PBM in CIA is superior to that of either MTX or PBM and that both work synergistically. Therefore, PBM with LED may be a potential therapeutic intervention for against RA.

Inflammatory augmentation of the delayed type hypersensitivity arthritis mouse model.

None declared.

Vaccines prevent reinduction of rheumatoid arthritis symptoms in collagen-induced arthritis mouse model.

Metabolic reprogramming of immune cells modulates their function and reduces the severity of autoimmune diseases. However, the long-term effects of the metabolically reprogrammed cells, specifically in the case of immune flare-ups, need to be examined. Herein, a re-induction rheumatoid arthritis (RA) mouse model was developed by injecting T-cells from RA mice into drug-treated mice to recapitulate the effects of T-cell-mediated inflammation and mimic immune flare-ups. Immune metabolic modulator paKG(PFK15 + bc2) microparticles (MPs) were shown to reduce clinical symptoms of RA in collagen-induced arthritis (CIA) mice. Upon re-induction, a significant delay in the reappearance of clinical symptoms in the paKG(PFK15 + bc2) microparticle treatment group was observed as compared to equal or higher doses of the clinically utilized U.S. Food and Drug Administration (FDA)-approved drug, Methotrexate (MTX). Furthermore, paKG(PFK15 + bc2) microparticle-treated mice were able to lower activated dendritic cells (DCs) and inflammatory T helper cell 1 (TH1) and increased activated, proliferating regulatory T-cells (Tregs) more effectively than MTX. The paKG(PFK15 + bc2) microparticles also led to a significant reduction in paw inflammation in mice as compared to MTX treatment. This study can pave the way for the development of flare-up mouse models and antigen-specific drug treatments.