Collagen-induced Arthritis Model Research Articles

The Potential Utility of (2S,4R)-4-[18F]fluoroglutamine as a Novel Metabolic Imaging Marker for Inflammation Explored by Rat Models of Arthritis and Paw Edema.

(2S,4R)-4-[18F]fluoroglutamine ([18F]FGln) is a promising metabolic imaging marker in cancer. Based on the fact that major inflammatory cells are heavily dependent on glutamine metabolism like cancer cells, we explored the potential utility of [18F]FGln as a metabolic imaging marker for inflammation in two rat models: carrageenan-induced paw edema (CIPE) and collagen-induced arthritis (CIA). The CIPE model (n = 4) was generated by injecting 200 µL of 3% carrageenan solution into the left hind paw three hours before the PET. The CIA model (n = 4) was generated by injecting 200µg of collagen emulsion subcutaneously at the tail base 3-4 weeks before the PET. A qualitative scoring system was used to assess the severity of paw inflammation. After a CT scan, 15.7 ± 4.9 MBq of [18F]FGln was injected via the tail vein, followed by a dynamic micro-PET scan for 90min under anesthesia with isoflurane. The standard uptake value of [18F]FGln was measured by placing a volume of interest in each paw. The non-injected right hind paws of the CIPE model rats served as controls for both models. The paws with CIA were pathologically examined after PET. The CIPE models showed a trend toward higher uptake in the injected paw compared to the non-injected paw (P = 0.068). In CIA models, uptake in the paws with severe inflammation was significantly higher than the controls (P = 0.011), while that with mild and no inflammation was slightly higher (33%) and lower (-7%), respectively. Combined overall, the [18F]FGln uptake in CIA showed a significant positive correlation with inflammation severity (r = 0.88, P = 0.009). The pathological findings confirmed profound inflammation in CIA. [18F]FGln uptake was increased in both acute and chronic inflammation, and the uptake level was significantly correlated with the severity, suggesting its potential utility as a novel metabolic imaging marker for inflammation.

LAMP3-mediated epithelial-mesenchymal transition promotes the invasion and excessive proliferation of fibroblast-like synoviocytes in rheumatoid arthritis.

The aim of this study was to explore the functional role of LAMP3-mediated epithelial-mesenchymal transition (EMT) in fibroblast-like synoviocytes (FLSs) in rheumatoid arthritis (RA) patients and to evaluate its potential as a therapeutic target. Changes in EMT and LAMP3 were investigated in the synovial tissue and FLSs of RA patients. In vitro experiments were performed using the EMT inhibitor C19, siRNA, and lentivirus to examine the impact of EMT and LAMP3 on RA-FLSs and the underlying mechanisms involved. Finally, C19 was administered to mice with collagen-induced arthritis (CIA) to validate the therapeutic efficacy of C19 in treating arthritis. Compared with patients with osteoarthritis (OA), RA patients exhibited increased EMT and increased expression of LAMP3 in the synovium. The results from the in vitro experiments demonstrated that inhibiting EMT effectively reduced the excessive proliferation, anti-senescent properties, migration, and invasive behavior of RA-FLSs, as well as the secretion of MMP1, MMP3, and MMP13. Additionally, regulating the expression of LAMP3 not only affected the EMT pathway but also impacted the excessive proliferation and invasive behavior of RA-FLSs. In the CIA model, administration of the EMT inhibitor C19 significantly alleviated the progression of arthritis. These findings demonstrate the inhibitory impact of EMT on arthritis and suggest that inhibiting EMT or LAMP3 may be a promising novel therapeutic approach for treating RA.

Inflammation-Targeted Vesicles for Co-delivery of Methotrexate and TNFα siRNAs to Alleviate Collagen-Induced Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease that has a complex pathogenesis and remains tough to treat. The clinical treatments with e.g. methotrexate (MTX) and TNF-α antibodies show fractional responses and lessen the symptoms only to a certain extent. Here, we developed inflammation-targeted vesicles codelivering methotrexate and TNF-α small interfering RNA (siTNFα) (ITV-MT) for effective ablation of collagen-induced arthritis (CIA) in mice. ITV-MT with tetra-mannose ligand and high loading of MTX (17.1 wt.%) and siTNFα (9.0 wt.%) displayed a small and uniform size (53 nm) and augmented uptake by inflammatory macrophages leading to superior regulation of macrophage phenotype from M1 to M2 in vitro compared to monotherapies. The intravenous injection of ITV-MT revealed clearly enhanced accretion in the inflamed joints. Interestingly, ITV-MT effectively repolarized M1 macrophages to M2 type, markedly reduced proinflammatory cytokine levels, and significantly attenuated symptoms including joint swelling, arthritis scores and bone damage in the CIA mouse models, by concurrently downregulating both adenosine and TNF-α pathways. This study highlights inflammation-targeted vesicles codelivering methotrexate and TNFα siRNA as a potential strategy to improved RA treatment. STATEMENT OF SIGNIFICANCE: Rheumatoid arthritis (RA) is regarded as an incurable disease, often referred to as an "incurable cancer". Current therapies, such as methotrexate (MTX) and anti-TNFα monoclonal antibodies, exhibit limited efficacy and severe adverse effects. The distinct physiochemical properties of MTX and siTNFα hinder their codelivery to RA joints and inflammatory cells. Here, we engineered inflammation-targeted vesicles (ITV-MT) for the codelivery of MTX and siTNFα to enhance therapeutic outcomes. Our findings reveal that ITV-MT significantly improves the drug uptake by macrophages, facilitating repolarization from M1 to M2 phenotypes. In CIA models, ITV-MT effectively downregulated proinflammatory cytokines while upregulating anti-inflammatory cytokines in RA joints, inhibited inflammatory cell infiltration in the synovium and protected against bone erosion. This study highlights that inflammation-targeted co-delivery of small molecular anti-RA agents and RNAi therapeutics may offer a compelling alternative to existing RA treatments, representing a promising strategy for RA treatment.

Effects of dioscin from Dioscorea nipponica on TL1A/DR3 and Th9 cells in a collagen-induced arthritis mouse model.

Rheumatoid arthritis (RA) is a systemic autoimmune disease, and TL1A and its receptor DR3 play important roles in its pathogenesis. Th9 cells are involved in RA development. Dioscin from Dioscorea nipponica (DDN) has a therapeutic effect on RA, but its effect on TL1A/DR3 and Th9 cells remains unclear. A collagen-induced arthritis (CIA) model was established in DBA/1 mice, and the therapeutic effects of DDN were determined using pathological sections and arthritis index scores. Western blotting and PCR were used to detect TL1A, DR3, PU.1, TGF-β and IRF-4. Enzyme-linked immunosorbent assay was used to detect the expression of TL1A and IL-9 in the serum. Immunofluorescence was used to detect the localization and expression of TL1A, DR3, and PU.1 in synovial tissue. Flow cytometry was used to detect TL1A and DR3 expression in different immune cells and Th9 cells. DDN ameliorated bone destruction, inflammatory cell infiltration, synovial inflammation, cartilage tissue destruction, and proteoglycan loss. DDN downregulated TL1A, DR3, and PU.1 in the synovium of the lymph nodes and spleen and TL1A and IL-9 in the serum. DDN decreased the number of TL1A-expressing APCs and macrophages, DR3-expressing CD4+T cells, and Th9 cells. Th9 cell differentiation-related factors TGF-β and IRF-4 were also inhibited by DDN. We conclude that DNN inhibited the expression of TL1A/DR3 in CIA mice and suppressed the expression of the Th9 cell-specific transcription factor PU.1, Th9 cell number, and IL-9 secretion. DDN inhibited the function of Th9 cells by targeting TGF-β and IRF-4 in the TL1A/DR3 pathway, thereby reducing inflammation.

Locally administered liposomal drug depot enhances rheumatoid arthritis treatment by inhibiting inflammation and promoting cartilage repair

Rheumatoid arthritis (RA) is a chronic autoimmune condition characterized by synovial hyperplasia, where inflammatory macrophages within the joint synovium produce multiple inflammatory cytokines, leading to cartilage damage. The development of therapeutic strategies that combine anti-inflammatory effects and cartilage repair mechanisms holds great promise for effective RA treatment. To address the limitations associated with the off-target effects of intravenous administration and the risk of synovial cavity infection with repeated local injections, we have innovatively developed a liposomal drug depot through hyaluronic acid (HA)-modified liposomes encapsulating dexamethasone sodium phosphate (DSP)-loaded nanogels, termed HA-Lipo@G/D. The nanogels were prepared by ionic cross-linking of chondroitin sulfate and gelatin, both of which have notable cartilage repair properties. In vitro studies demonstrated that this formulation exhibited sustained drug release, enhanced uptake by inflammatory macrophages, reduced secretion of inflammatory factors (TNF-α, IL-1β), and significantly decreased chondrocyte apoptosis induced by inflammatory factors. Moreover, in vivo assessments in a rat model of collagen-induced arthritis revealed effective accumulation of the liposomal drug depot at the inflamed joint site, resulting in macrophage repolarization and cartilage tissue repair. Our findings provide a synergistic strategy for inhibiting inflammation and mitigating cartilage damage through local joint cavity injection, thereby enhancing the therapeutic efficacy of RA.Graphical

Pharmacokinetic and Pharmacodynamic Study of Folic Acid-Modified Chitosan–Stearic Acid Nanomicelles Loaded with Tetrandrine for Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease, and it is currently incurable. Tetrandrine (TET) has an obvious curative effect with therapeutic efficacy on RA, but its use is limited due to its poor water-solubility and bioavailability. Therefore, TET-loaded nanomicelles modified with chitosan, stearic acid, and folic acid (FCST) was prepared in the study, and the pharmacokinetics and pharmacodynamics were studied. Methods: The plasma concentrations of FCST and TET were measured by the PLC-MS/MS method at different times, and the pharmacokinetic parameters were calculated. A collagen-induced arthritis (CIA) model was established with rats. On the 16th day after the first immunization, 50 rats were randomized into five groups with 10 rats in each group according to the arthritis score. The drugs were administered by intraperitoneal injection for 30 days. The swelling degree and joint score of the rats were tested during each administration. In addition, the pro-inflammatory factors IL-1β, IL-6, IL-17, and TNF-α in the serum of the rats were tested by an ELISA kit, and their joints were examined by histopathology. Results: Pharmacokinetic studies showed that the AUC0–72h of FCST was 1.93 times that of TET. FCST demonstrated higher bioavailability compared to TET (p < 0.05). Pharmacodynamic studies demonstrated that FCST had significant anti-inflammatory effects, and its anti-inflammatory activity was stronger compared to the same dose of TET, as evidenced by measuring toe thickness and observing toe appearance. It significantly reduced the expression of IL-1, IL-6, IL-17, and TNF-α in rats with rheumatoid arthritis (p < 0.05). Conclusions: FCST can significantly improve bioavailability and has a significant therapeutic effect on rheumatoid arthritis.

MtSTAT3 suppresses rheumatoid arthritis by regulating Th17 and synovial fibroblast inflammatory cell death with IL-17-mediated autophagy dysfunction

Th17 cells are activated by STAT3 factors in the nucleus, and these factors are correlated with the pathologic progression of rheumatoid arthritis (RA). Recent studies have demonstrated the presence of STAT3 in mitochondria, but its function is unclear. We investigated the novel role of mitochondrial STAT3 (mitoSTAT3) in Th17 cells and fibroblast-like synoviocytes (FLSs) and analyzed the correlation of mitoSTAT3 with RA. We used a collagen-induced arthritis (CIA) mouse model to determine the effect of mitochondrial STAT3. We observed changes in the RA mouse model via the use of a mitochondrial STAT3-inducing vector and inhibitor. We observed the accumulation of abnormal autophagosomes, increased inflammatory cell death signaling, and decreased mitoSTAT3 activity in FLSs from both patients with RA and patients with IL-17-treated FLSs. We first discovered that IL-17 increased the accumulation of abnormal autophagosomes and the expression of inflammatory cell death factors in synovial fibroblasts and decreased mitoSTAT3 activation. In a mouse model of CIA, arthritis and joint inflammation were decreased by injection vectors that induced mitoSTAT3 overexpression. The abnormal accumulation of autophagosomes and the expression of inflammatory cell death factors were also decreased in these mice. In mouse and human immune cells, ZnSO4, an inducer of mitochondrial STAT3, decreases the production of reactive oxygen species, the IL-17 concentration, and differentiation into Th17 cells. However, mitoSTAT3 blockade accelerated the development of arthritis, inflammatory cell death, and abnormal autophagosome/autophagolysosome formation. Therefore, this study suggests a novel inhibitory mechanism of RA using mitoSTAT3 via the regulation of autophagy, Th17 differentiation, and inflammatory cell death.

Analyzing How Zhizi Baipi Decoction Regulates VEGF to Suppress RA Angiogenesis Using Network Pharmacology and Experimental Validation.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily manifests with symptoms such as heat and toxin. However, the key components and molecular mechanisms of Zhizi Baipi decoction (ZBD) in the treatment of RA are still unclear. The study aimed to explore the mechanism of action of ZBD for treating RA through ingredient analysis, network pharmacology, and experimental validation. The chemical constituents of ZBD were identified by ultra-high performance liquid chromatography coupled with Q-TOF-mass spectrometry (UPLC-Q-TOF-MSE). Additionally, the active ingredients of ZBD treating RA were screened by network pharmacology and using molecular docking to verify the binding energy of the active ingredients and ZBD's targets. Then we elucidated ZBD's mechanism of action on collagen-induced arthritis (CIA) model rats. Subsequently, experimental validations were used to validate the findings of network pharmacology. A total of 84 chemical constituents was identified by UPLC-Q-TOF-MSE. The results of network pharmacology indicated that ZBD could exert its therapeutic effect on RA through the vascular endothelial growth factor (VEGF) pathway. Molecular docking revealed a strong binding capacity between the target KDR and the active ingredients. Additionally, we quantified the five active ingredients of ZBD. Invivo experiments demonstrated that ZBD inhibited synovial angiogenesis and alleviated the occurrence and progression of RA. Overall, ZBD has a significant therapeutic effect on RA. The results of qualitative analysis, network pharmacology, molecular docking, and invivo experiments indicated that the main active components of ZBD could modulate the VEGF pathway to treat RA.

3-MA attenuates collagen-induced arthritis in vivo via anti-inflammatory effect and autophagy inhibition

BackgroundRheumatoid arthritis (RA) is a chronic autoimmune disease which afflicts about nearly 1% of global population. RA results in synovitis and cartilage/bone damage, even disability which aggravates the health burden. Many drugs are used to relieve RA, such as glucocorticoids (GCs), non-steroidal anti-inflammatory drugs (NSAIDs), and disease-modifying anti-rheumatic drugs (DMARDs) in the clinical treatment. However, present clinical drugs have various disadvantages such as poor bioavailability and short biological half-life and drug resistance, or adverse effects. A recent study showed autophagy modulation may be a novel strategy in the treatment of RA. 3-Methylademine (3-MA), is the most widely used autophagy inhibitor, which blocks autophagy at the initiation and maturation stages. The aim of this study is to evaluate the effect of 3-MA in collagen-induced-arthritis (CIA) mice and further elucidate how 3-MA attenuated inflammation, and cartilage/bone damage in arthritis.MethodsAn in-vivo mouse collagen-induced arthritis model was applied to compare differences in ankle destruction among control mice and CIA mice treated with or without 3-MA. Bone and cartilage destruction degree was evaluated by histology and micro-computed tomography (µCT). Further in-vivo assays utilized mouse serum samples to investigate inflammatory levels, oxidative levels, and bone resorption cytokines. At last, an immunofluorescence assay was applied to detect the autophagy level among the three groups.ResultsThe in-vivo mouse collagen-induced arthritis model showed that CIA mice revealed apparent hind paw and ankle swelling which was aggravated gradually along with time, while 3-MA treatment attenuated swelling gradually. µCT and histological results showed typical lesions in CIA group while 3-MA treatment alleviated arthritis-related destruction. Serum assay showed that 3-MA significantly reduced inflammatory cytokines levels, suppressed oxidative levels and bone resorption cytokines. Immunofluorescence assay revealed 3-MA significantly inhibited the abnormal autophagy level in CIA mouse ankle.Conclusions3-MA protects bone destruction in CIA-induced mice arthritis by anti-inflammatory effect and autophagy inhibition.

M3-DPPE Liposomal Nanoparticles Encapsulating CLEC12A Enhance CD206-Mediated Endocytosis and Efficacy in the Collagen-Induced Arthritis Model.

This study aimed to investigate the efficacy of M3-DPPE liposomal nanoparticles encapsulated with mRNA encoding cytokines (M3-mRNAs) in targeting macrophages for the treatment of inflammation-induced joint injury. in vitro, M3-mRNAs were administered to peritoneal exudate macrophages (PEMs), and the uptake was assessed using flow cytometry. The mechanism of uptake was investigated by blocking the CLEC12A pathway with M3-SiCLEC12A and observing CD206-mediated endocytosis. In vivo, the distribution of Dir-labeled M3-drugs was monitored using IVIS imaging, and its accumulation in inflammatory and noninflammatory areas was evaluated. The therapeutic potential was evaluated in collagen-induced arthritis (CIA) model mice by assessing macrophage polarization, joint pathology, and cytokine expression. in vitro studies demonstrated that M3-mRNAs were taken up significantly by PEMs via CD206-mediated endocytosis. In vivo imaging showed that Dir-labeled M3-drugs accumulated predominantly in inflammatory areas and subsequently in bone injury joints. Treatment with M3-drugs in collagen-induced arthritis model mice increased the population of F4/80+ and F4/80+/CD206+ M2 macrophages in inflamed joints, leading to reduced joint fibrosis and modulation of cytokine levels, including decreased pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, and INF-γ) and increased anti-inflammatory cytokines (IL-10 and TGF-β). M3-SiCLEC12A enhanced CD206-mediated endocytosis of M3-mRNAs and M3-drugs in macrophages, promoting the production of corresponding proteins and modulating the immune microenvironment. This treatment approach shows promise in repairing inflammation-induced bone and joint injury by balancing pro-inflammatory and anti-inflammatory cytokines. However, further research is required to address drug tolerance and safety concerns and minimize potential side effects before clinical application in autoimmune diseases caused by inflammation.

The potential of autologous patient-derived circulating extracellular vesicles to improve drug delivery in rheumatoid arthritis.

Recognizing the need for innovative therapeutic approaches in the management of autoimmune diseases, our current investigation explores the potential of autologous extracellular vesicles (EVs), derived from the blood of rheumatoid arthritis patients, to serve as therapeutic vectors to improve drug delivery. We found that circulating EVs derived from arthritic mice (collagen-induced arthritis model) express the joint/synovia homing receptor, αVβ3 integrin. Importantly, both autologous labeled EVs, derived from the blood of arthritic mice (collagen antibody-induced arthritis model) and healthy mice-derived EVs, exhibit targeted migration toward inflamed synovia without infiltrating healthy joints, as demonstrated by an in vivo imaging system. Furthermore, EVs derived from plasma of rheumatoid arthritis patients show an overexpression of αV integrin and are effectively taken up by lipopolysaccharides/tumornecrosis factor alpha (TNFα)-induced activated human synovial cell line in vitro, although interestingly the uptake of healthy EVs was found to be significantly increased. Notably, arthritic mice-derived circulating EVs, strongly express murine glucose transporter 1, which in turn can facilitate their binding to glucose-coated gold nanoparticles (previously shown to be conjugated with drugs for improved drug delivery). The significance of our results, lies in the identification of autologous tissue homing EVs as promising vectors, offering a novel avenue to enhance targeted delivery of anti-inflammatory/rheumatic drugs in rheumatoid arthritis treatment.

Sea-Island Micelle Structured Hydrogel Scaffold: A Dual-Action Approach to Combat Cartilage Damage under RA Conditions.

Rheumatoid arthritis (RA) is a common autoimmune joint disease characterized by persistent synovial inflammation and cartilage damage. The current clinical treatments primarily utilize drugs such as triptolide (TP) to address inflammation, yet they are unable to directly repair damaged cartilage. Furthermore, the persistent inflammation often undermines the effectiveness of traditional cartilage repair strategies, preventing them from achieving optimal outcomes. To tackle this challenge, this study successfully developed a drug-loaded polyurethane hydrogel-oriented porous scaffold, designed to address persistent inflammation and facilitate cartilage repair under RA conditions. A drug-loaded hydrogel was formed via solvent-induced polyurethane-gelatin, resulting in the scaffold TP@GSPU. The sea-island micelle structure of TP@GSPU enables efficient loading of TP. The release of TP in the in vivo environment regulates the expression of inflammatory factors in macrophages, thereby improving the inflammatory microenvironment within the joint cavity. Additionally, the gelatin component of the scaffold provides robust support for cartilage regeneration. The efficacy of the TP@GSPU in regulating the inflammatory microenvironment and facilitating cartilage repair under RA conditions, which was demonstrated through cartilage damage repair experiments conducted in a rat collagen-induced arthritis (CIA) model. The design scheme of this material offers a potential approach to cartilage repair in the conditions of RA.

Regulation of macrophage polarization and pyroptosis by 4-methylcatechol alleviates collagen-induced arthritis via Nrf2/HO-1 and NF-κB/NLRP3 signaling pathways.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to joint deformity and ultimately disability. The metabolite of quercetin, 4-Methylcatechol (4-MC), has been acknowledged for its anti-inflammatory and antioxidant properties; however, the protective effects of 4-MC on RA and its underlying mechanisms remain incompletely elucidated. In a collagen-induced arthritis (CIA) model, we observed that 4-MC effectively mitigated joint inflammation and bone destruction in CIA mice. Additionally, it significantly suppressed the upregulated expression of inflammatory cytokines in synovial tissues. Mechanistically, upon lipopolysaccharide (LPS) stimulation, 4-MC inhibited M1 polarization of macrophages and induced a phenotypic switch from M1 to M2 phenotype, thereby reducing the release of pro-inflammatory cytokines by M1 macrophages while increasing the release of anti-inflammatory cytokines by M2 macrophages. Furthermore, it attenuated LPS/adenosine triphosphate (ATP)-induced pyroptosis in macrophages by downregulating NLRP3 expression levels along with cleaved caspase-1, cleaved IL-1β, and GSDMD-NT expression levels. Notably, our findings revealed that 4-MC exerted inhibitory effects on the NF-κB signaling pathway through specific modulation of the NF-κB complex as well as phosphorylation of the upstream IKK kinase complex. Collectively, these results highlight significant therapeutic potential for utilizing 4-MC in RA treatment.

Yu-Xue-Bi capsule ameliorates aggressive synovitis and joint damage in rheumatoid arthritis via modulating the SUCNR1/HIF-1α/TRPV1 axis.

Specific treatment for rheumatoid arthritis (RA) is still an unmet need. Yu-Xue-Bi (YXB) capsule effectively treats RA with blood stasis syndrome (BS). However, its mechanism remains unclear. Exploring and elucidating the therapeutic effect and pharmacological mechanism of YXB capsule in treating RA. This study identified differentially expressed genes (DEGs) in patients with RA and BS compared to healthy controls using clinical transcriptomics data. Clinical symptoms of RA and BS, and the related genes were collected from the SoFDA and HPO databases. Candidate bioactive constituents in YXB were identified via UPLC-QTOF/MS and evaluated using ADMET rules. Putative targets were predicted, and a network linking disease-related DEGs and drug targets was constructed. Key targets were screened utilizing random walk-with-restart (RWR) algorithms and verified through experiments using rat models of collagen-induced arthritis with BS (CIA-BS model) in vivo. We found 1220 DEGs along with 976 clinical symptom-related genes, as RA with BS-related genes. Chemical profiling identified 193 YXB constituents, with 98 meeting optimal ADMET criteria. We predicted 459 putative targets for these constituents. Network calculations screened 209 key targets, 129 RA with BS-related genes and 92 YXB targets involved in immune inflammation, blood stagnation, and hyperalgesia imbalance. Notably, the SUCNR1/HIF-1α/TRPV1 axis was enriched by YXB targets against RA with BS. Experimentally, YXB inhibited inflamed joint deterioration, including synovial inflammation, cartilage damage and bone erosion, relieving mechanical and cold allodynia hyperglasia. It reversed hemorrheology and vascular function in CIA-BS rats, restoring SDHB and eNOS expression, preventing SDHA, SUCNR1 and HIF-1α activation, reducing SUCN, TNF-α and IL-1β production, and TRPV1 and TRPA1 expression. Our data support YXB's therapeutic effects on aggressive RA-BS by modulating the SUCNR1/HIF-1α/TRPV1 axis.

MiR-378 exaggerates angiogenesis and bone erosion in collagen-induced arthritis mice by regulating endoplasmic reticulum stress

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by pain, inflammation, and discomfort in the synovial joints. It is critical to understand the pathological mechanisms of RA progression. MicroRNA-378 (miR-378) is highly expressed in the synovium of RA patients and positively correlated with disease severity, but its function and underlying mechanisms remain poorly understood. In this study, miR-378 transgenic (miR-378high) mice were used to construct the collagen-induced arthritis (CIA) model for exploring the role of miR-378 in RA development. miR-378high CIA mice showed accelerated RA development, as evidenced by exaggerated joint swelling and bone structural deformities. More severe endoplasmic reticulum (ER) stress and the consequent angiogenesis and osteoclastogenesis were also activated in the synovial tissue and calcaneus, respectively, in the miR-378high group, suggesting that ER plays a significant role in miR-378-mediated RA pathogenesis. Upon in vitro RA induction, fibroblast-like synoviocytes (FLSs) isolated from miR-378high mice showed a higher expression level of ER stress markers. The conditioned medium (CM) from RA-FLSs of miR-378high mice stimulated more intensive angiogenesis and osteoclastogenesis. The ER stress-related protein Crebrf was identified as a downstream target of miR-378. Crebrf knockdown diminished the promoting effect of miR-378 on ER stress, as well as its downstream angiogenesis and osteoclastogenesis activities. Tail vein injection of anti-miR-378 lentivirus in an established RA mouse model was shown to ameliorate RA progression. In conclusion, miR-378 amplified RA development by promoting ER stress and downstream angiogenesis and osteoclastogenesis, thus indicating that miR-378 may be a potential therapeutic target for RA treatment.

Kaempferol Improved Rheumatoid Arthritis by Regulating the Immune Imbalance of Treg/Th17.

The objective of this study was to explore the therapeutic effects of kaempferol (Kae) on rheumatoid arthritis (RA) and to elucidate the underlying mechanisms. The collagen-induced arthritis (CIA) model was established using collagen II to induce RA. Mice were treated with Kae at a dose of 25 or 50 mg/kg/day via gavage. Pathological changes in the ankle joint were analyzed. Enzyme-linked immunosorbent assay (ELISA) was employed to measure the levels of inflammatory factors. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to assess the expression of genes associated with the balance of regulatory T (Treg)/T helper 17 (Th17) cells. Flow cytometry was utilized to determine the Treg/Th17 ratio. Furthermore, these techniques were employed to evaluate the impact of miR-34a and Foxp3 dysregulation on cellular functions in RA under the influence of Kae. Dual luciferase reporter assay was conducted to analyze the binding of miR-34a to Foxp3. Treatment with Kae led to a downregulation of receptor-related orphan receptor gamma t (RORγt) and IL-17 expression, and an upregulation of Foxp3, IL-10, and TGF-β expression in CIA mice. Kae intervention inhibited the production of proinflammatory cytokines and increased the production of anti-inflammatory cytokines. Furthermore, Kae treatment suppressed the expression of miR-34a, which was identified as a target of miR-34a. Finally, Kae regulated Treg/ Th17 balance-related genes and cellular inflammation through the miR-34a/Foxp3 axis. The study demonstrated that Kae effectively ameliorates CIA in mice by modulating the Treg/Th17 balance and related genes via the miR-34a/Foxp3 axis. These findings suggest that Kae may serve as a promising therapeutic agent for the treatment of RA and for restoring immune homeostasis.

From Tea to Functional Foods: Exploring Caryopteris mongolica Bunge for Anti-Rheumatoid Arthritis and Unraveling Its Potential Mechanisms.

Caryopteris mongolica Bunge (CM) shows promising potential for managing rheumatoid arthritis (RA) and digestive disorders, attributed to its rich content of bioactive compounds such as polyphenols and flavonoids. Despite its common use in herbal tea, the specific mechanisms underlying CM's anti-inflammatory and joint-protective effects remain unclear, limiting its development as a functional food. This study investigated the effects of aqueous CM extract on RA in collagen-induced arthritis (CIA) rats and explored the underlying mechanisms. Forty-eight female Sprague-Dawley rats were randomly assigned to six groups (n = 8): normal control, CIA model, methotrexate (MTX), and CM high-, middle-, and low-dose groups. Anti-inflammatory and joint-protective effects were evaluated using biochemical and histological analyses. To elucidate the mechanisms, we applied metabolomics, network pharmacology, and transcriptomics approaches. The results demonstrated that CM extract effectively suppressed synovial inflammation in CIA rats, reducing joint degradation. CM's anti-inflammatory effects were mediated through the TNF signaling pathway, modulating glycerophospholipid and amino acid metabolism, including reduced levels of tryptophan, LysoPC, and asparagine. Molecular docking identified scutellarin and apigenin as key bioactive compounds. Additionally, immunofluorescence analysis revealed CM's therapeutic effects via TNF signaling inhibition and suppression of M1 macrophage polarization. These findings highlight the therapeutic potential of CM for RA and support its development as a functional food or pharmaceutical product.

IL-37 Isoform A Prevents Collagen-Induced Arthritis in Mice by Modulating the Th17/Treg Balance via IL1R8 Receptors.

Cytokines play a complex and pivotal role in modulating synovitis in rheumatoid arthritis. Interleukin (IL)-37 is known for its extensive anti-inflammatory properties that set it apart from the majority of other IL-1 family members. However, IL-37a, a member of the IL-37 family, lacks research into rheumatoid arthritis. This research aims to explore the role of IL-37a in regulating T-cell homeostasis in rheumatoid arthritis using the Collagen-Induced Arthritis(CIA) model. IL-37atg mice, a genetically altered strain carrying the human IL-37a gene, were used to test the influence of this cytokine on the progression of arthritis. The results show that IL-37atg mice demonstrated a notable reduction in both the incidence and severity of arthritis relative to WT mice. The protective effect was accompanied by lower levels of cytokines in plasma and synovial tissues (such as IL-17A and IL1β) that drive the inflammatory response. The ratio of Th17/Treg decreased in the lymph nodes of IL-37atg mice. However, the knockout of IL1R8 in IL37atg mice eliminated the effects of IL-37a. Additionally, transcriptomic analysis revealed that Th17 cell differentiation is a key pathway through which IL-37a exerts its protective effects, and experiments confirmed that IL-37a suppresses Th17-polarizing in vitro.

Transcriptomic Analysis of Blood Collagen-Induced Arthritis Mice Exposed to 0.1 THz Reveals Inhibition of Genes and Pathways Involved in Rheumatoid Arthritis.

Inflammation plays an essential role in the phases of rheumatoid arthritis (RA) as the joints secrete a range of molecules that modulate the inflammatory process. While therapies based on physical properties have shown effectiveness in a range of animal experimental models, the understanding of their biological mechanisms remains unclear. The aim of this study was to investigate the immunomodulatory effects of a 0.1 terahertz (THz) wave in rheumatoid arthritis in an attempt to dissect the molecular pathways implicated. The collagen-induced rheumatoid arthritis (CIA) model joint mice were irradiated daily for 30 min over a period of 2 weeks with continuous 0.1 terahertz waves. High-throughput bulk RNA sequencing of the murine blood was performed to analyze and characterize the differences in gene expression changes between the control (Ctrl), CIA (RA), and CIA exposed to THz. Differentially expressed genes, canonical pathway analysis, gene set enrichment, and protein-protein interaction were further run on the selected DEGs. We found that terahertz exposure downregulated gene ontologies representing the "TGF-β signaling pathway", "apoptosis", "activation of T cell receptor signaling pathway", and "non-canonical NF-κB signal transduction". These observations were further confirmed by a decreased level in the expression of transcription factors Nfib and Nfatc3, and an increased level of Lsp1. In addition, the expression of Mmp8 was significantly restored. These results indicate that THz ultimately attenuates the inflammatory response of hemocytes through the T cell and NF-κB pathway, and these changes are reverberated in the blood transcriptome. In this first report of transcriptome sequencing in a model of rheumatoid arthritis exposed to terahertz waves, the downregulated DEGs were associated with anti-inflammatory effects.

High-fat diet stimulated butyric acid metabolism dysbiosis, altered microbiota, and aggravated inflammatory response in collagen-induced arthritis rats.

Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, Dysbiosis of intestinal microbiota and their metabolites has been linked to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear.In this study, we explored the impact of high fat diet(HFD) on collagen-induced arthritis (CIA) rats and revealed its mechanisms based on gut microbiota and metabolomics. Based on diet and modeling, rats were divided into normal group (Con), CIA model group, HFD group (HFD), and HFD + CIA group (HCIA). The effect of HFD on arthritis in CIA rats were investigated based on the arthritis index (AI), weight, blood lipid levels, and inflammatory cytokines. Moreover, HE staining and micro-CT were performed to evaluated the effect of HFD on the pathology of joints and synovial tissues in CIA rats.16S rRNA amplicon sequencing and liquid chromatography-mass spectrometry (LC-MS) were employed to explore changes in gut microbiota and short-chain fatty acids (SCFAs). The AI scores, inflammatory cytokines and bone destruction parameters in the HCIA group were significantly higher than those in the other three groups. The results of 16S rRNA amplicon sequencing and metabolomics showed that compared with the other three groups, the expression of g_Muribaculaceae and butyric acid were reduced in the HCIA group. Spearman and linear correlation analyses revealed a positive correlation between g_Muribaculaceae abundance and butyric acid levels. HFD stimulated butyric acid metabolism dysbiosis, altered microbiota, and aggravated inflammatory response in CIA rats.