Synovial Cells Research Articles

The Mechanisms and Quality Markers of Anti-rheumatoid Arthritis of Traditional Chinese Medicine.

RA is a recurrent autoimmune disease that has significant adverse effects on the physical and mental health of patients. Traditional Chinese medicine has shown significant advantages in the prevention and treatment of RA. Numerous clinical and experimental studies have confirmed that traditional Chinese medicine components have clear therapeutic effects and minimal adverse reactions in treating RA. The research on traditional Chinese medicine for the prevention and treatment of RA has become a hot topic in the field of autoimmune diseases. The related references about the mechanisms and Q-markers of anti-RA of traditional Chinese medicine in this review were collected from Willy, SpringLink, Web of Science, Elsevier, PubMed, SciFinder, Scopus, ACS publications, Baidu Scholar, Google Scholar, and CNKI. The traditional Chinese medicine components such as terpenoids, flavonoids, and alkaloids have significant anti-RA effects, and their mechanisms are mainly to inhibit NF-κB signaling pathway, inhibit the proliferation of RA fibroblasts like synovial cells, and regulate Th1/Th2 cell balance, and so on. Predicting and studying the Q-markers of traditional Chinese medicine anti-RA by plant phylogeny and chemical componentss, traditional medicinal properties, pharmacokinetics, component measurability, correlation between composition and efficacy, and gut microbiota will provide scientific foundations for the research and further development of anti-RA traditional Chinese medicine. The active components of traditional Chinese medicine exhibited the characteristic of multiple mechanisms in the treatment of RA, such as terpenoids had anti-angiogenesis effects, flavonoids had anti-inflammatory and cartilage protective effects, and alkaloids had antiinflammatory and analgesic effects. The proposal of Q-markers for anti-RA provided new research ideas for promoting the development of new drugs for anti-RA and ensuring the safety and effectiveness of clinical medications.

Mycoplasma synoviae surface-located elongation factor G functions as a cytoadhesin to promote adhesion to synovial sheath cells through binding to vimentin

Mycoplasma synoviae infection has caused serious economic losses to the poultry industry worldwide. The molecular mechanism by which M. synoviae colonizes the synovium and induces synovitis is unclear. In this study, desthiobiotin pull-down and liquid chromatography‐tandem mass spectrometry analyses were used to screen M. synoviae membrane proteins that bind the membrane proteins of synovial sheath cells (SSCs). Among the 128 screened proteins, elongation factor G (EF-G) of M. synoviae was identified as a surface-located protein using colony blotting and dual fluorescence analyses. The immunogenicity of EF-G was confirmed by the preparation of a rabbit polyclonal antibody. EF-G was identified as a cytoadhesin that directly binds to SSCs using indirect immunofluorescence assay and ELISA plate binding assay. In addition, antibody adhesion inhibition and protein adhesion inhibition demonstrated that EF-G could significantly promote the adhesion of M. synoviae to SSCs. Co-IP, GST pull-down, bacterial two-hybridization, and ELISA plate binding assays were performed to demonstrate the binding of EF-G and vimentin in vivo and in vitro. Antibody adhesion inhibition, protein adhesion inhibition, and siRNA interference adhesion inhibition assays demonstrated that vimentin significantly affected M. synoviae adhesion to SSCs. These studies indicate that two interacting proteins, EF-G, a novel cytoadhesin, and vimentin, an important cell surface receptor, play important roles in the adhesion of M. synoviae to SSCs, laying a foundation for subsequent studies on the mechanism of M. synoviae-induced synovitis and providing meaningful targets for screening target drugs against M. synoviae infection.

Endoscopic En Bloc Resection of Giant Cell Tumor of Tendon Sheath of Anterior Ankle

Giant cell tumor of the tendon sheath (GCTTS) originates from the synovial cells of the tendon sheath. It is one of the most common benign soft-tissue tumors of the foot and ankle affecting the joints, bursae, and tendon sheaths and can behave in a locally aggressive manner. Complete surgical resection with long-term follow-up is the preferred treatment. Because GCTTS is a benign condition, the equilibrium between the quality of the surgical margins and functional preservation should be considered. If more aggressive resection is applied, the outcome may negatively affect quality of life, whereas incomplete resection may lead to recurrence. The purpose of this technical note is to describe the details of endoscopic en bloc resection of GCTTS of the anterior ankle. This endoscopic approach can provide a magnified view of the operative site, allowing accurate surgical assessment to ensure complete resection of the lesion without damage to the adjacent normal structures.

Definition of Synovial Mesenchymal Stem Cells for Meniscus Regeneration by the Mechanism of Action and General Amp1200 Gene Expression.

The quality control (QC) of pharmaceutical-grade cell-therapy products, such as mesenchymal stem cells (MSCs), is challenging. Attempts to develop such products have been hampered by difficulties defining cell-type-specific characteristics and therapeutic mechanisms of action (MoAs). Although we have developed a cell therapy product, FF-31501, consisting of human synovial MSCs (SyMSCs), it was difficult to find specific markers for SyMSCs and to define the cells separately from other MSCs. The purpose of this study was to create a method for identifying and defining SyMSCs from other tissue-derived MSCs and to delve deeper into the mechanism of action of SyMSC-induced meniscus regeneration. Specifically, as a cell-type-dependent approach, we constructed a set of 1143 genes (Amp1200) reported to be associated with MSCs and established a method to evaluate them by correlating gene expression patterns. As a result, it was possible to define SyMSCs separately from other tissue-derived MSCs and non-MSCs. In addition, the gene expression analysis also highlighted TNSF-15. The in vivo rat model of meniscus injury found TNSF-15 to be an essential molecule for meniscus regeneration via SyMSC administration. This molecule and previously reported MoA molecules allowed an MoA-dependent approach to define the mechanism of action for SyMSCs. Therefore, SyMSCs for meniscus regeneration were defined by means of two approaches: the method to separate them from other MSCs and the identification of the MoA molecules. These approaches would be useful for the QC of cell therapy products.

Loss of synovial tissue macrophage homeostasis precedes rheumatoid arthritis clinical onset.

This study performed an in-depth investigation into the myeloid cellular landscape in the synovium of patients with rheumatoid arthritis (RA), "individuals at risk" of RA, and healthy controls (HC). Flow cytometric analysis demonstrated the presence of a CD40-expressing CD206+CD163+ macrophage population dominating the inflamed RA synovium, associated with disease activity and treatment response. In-depth RNA sequencing and metabolic analysis demonstrated that this macrophage population is transcriptionally distinct, displaying unique inflammatory and tissue-resident gene signatures, has a stable bioenergetic profile, and regulates stromal cell responses. Single-cell RNA sequencing profiling of 67,908 RA and HC synovial tissue cells identified nine transcriptionally distinct macrophage clusters. IL-1B+CCL20+ and SPP1+MT2A+ are the principal macrophage clusters in RA synovium, displaying heightened CD40 gene expression, capable of shaping stromal cell responses, and are importantly enriched before disease onset. Combined, these findings identify the presence of an early pathogenic myeloid signature that shapes the RA joint microenvironment and represents a unique opportunity for early diagnosis and therapeutic intervention.

Synovial fluid analysis in healthy green turtles Chelonia mydas in Taiwan.

Septic arthritis is a frustrating disease in sea turtle rehabilitation because of its unclear pathogenesis, delayed onset during rehabilitation, long-term treatment requirements, and potentially poor prognosis. Radiography, blood cultures, and arthrocentesis have been used as diagnostic tools for suspected cases. However, there is currently a lack of data on the characteristics of synovial fluid in healthy sea turtles. To establish reference data for synovial fluid in sea turtles, we enrolled 14 green turtles Chelonia mydas rescued between 2019 and 2022 from 3 facilities using the following inclusion criteria: normal attitude and appetite, normal motor functions of the 4 limbs, no joint swelling, and no ongoing use of antibiotics for at least 1 mo. Bacterial cultures of blood and synovial fluid from the shoulder joints of these turtles were obtained and a qualitative analysis of the synovial fluid was performed. The results revealed bacterial culture-negative blood and synovial fluids at 37°C. Most characteristics of normal synovial fluid in green turtles, such as being transparent, colorless, and able to create a strand of over 2.5 cm by being pulled with a needle in viscosity trials, as well as the cytology of the normal synovial fluids being dominated by histiocytes and synovial lining cells, lymphocytes, and occasionally a few heterophils or erythrocytes were similar to those in mammals. This study provides information on the normal synovial fluid characteristics of green turtles in Taiwan, which may be beneficial for the diagnosis of joint diseases in sea turtles.

Contemporary insights and prospects on ferroptosis in rheumatoid arthritis management.

Rheumatoid arthritis (RA) is a common autoimmune disease characterized primarily by persistent synovial inflammation and joint destruction. In recent years, ferroptosis, as a novel form of cell death, has garnered widespread attention due to its critical role in various diseases. This review explores the potential mechanisms of ferroptosis in RA and its relationship with the pathogenesis of RA, systematically analyzing the regulatory role of ferroptosis in synovial cells, chondrocytes, and immune cells. We emphasize the evaluation of ferroptosis-related pathways and their potential as therapeutic targets, including the development and application of inhibitors and activators. Although ferroptosis shows some promise in RA treatment, its dual role and safety issues in clinical application still require in-depth study. Future research should focus on elucidating the specific mechanisms of ferroptosis in RA pathology and developing more effective and safer therapeutic strategies to provide new treatment options for RA patients.

Regulating the lncRNA DSCR9/RPLP2/PI3K/AKT axis: an important mechanism of Xinfeng capsules in improving rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic and symmetrical polyarthritis. RA patients often experience inflammatory reaction and hypercoagulable state, which together affect the self-perception of patient (SPP). Currently, inhibiting inflammation and hypercoagulable state are common treatment methods for alleviating RA symptoms. Xinfeng Capsules (XFC) has a long history of treating RA, and can effectively improve the inflammatory response and hypercoagulable state of RA. However, the potential mechanisms have not yet been determined. This study elucidated the action mechanism of XFC in RA inflammation and hypercoagulability through the lncDSCR9/RPLP2/PI3K/AKT axis. Clinical observations indicated that there was a strong link between XFC therapy and improvements in inflammatory and coagulation biomarkers, as well as SPP among RA patients. The subsequent network pharmacology analysis results identified the PI3K/AKT signaling pathway as a potential mediator for XFC treatment of RA. Furthermore, clinical validation and sequencing results revealed that lncRNA DSCR9 expression (a gene implicated in inflammation and coagulation) was negatively correlated with clinical markers of inflammation and coagulation, while positively correlated with SF-36 indicators. Notably, XFC treatment remarkably upregulated lncRNA DSCR9 expression and downregulated PI3K and AKT expressions, showing opposite expression trends to the untreated cases.The regulatory effect of XFC on the lncRNA DSCR9/RPLP2/PI3K/AKT axis in RA was investigated using techniques such as RNA pull-down assay, Western blot analysis, RT-PCR, and EdU assay. Moreover, the administration of the PI3K/AKT agonist RMH can counteract the effects of XFC on p-PI3K, p-AKT, inflammation, and hypercoagulability, reinforcing the role of pathway. Finally, animal studies utilizing HE staining and transmission electron microscopy (TEM) demonstrated that XFC notably decreased PI3K and AKT expressions in adjuvant-induced arthritis (AA) rats, mitigated inflammation and hypercoagulability, and enhanced the ultrastructure of synovial cells. These findings underscored the potential mechanisms of XFC in the treatment of RA. Regulating the lncRNA DSCR9/RPLP2/PI3K/AKT axis may be an important mechanism by which XFC improved RA inflammatory response and hypercoagulable state.

The Impact of Wharton's Jelly-derived Exosomes on the Production of Inflammatory Mediators from HIG-82 Synoviocytes.

Osteoarthritis (OA) is the most common joint disease worldwide. Routine treatment options are limited, and total knee replacement surgeries often come with complications. In recent years, the use of biologics, such as Wharton's jelly (Wj) derived from the umbilical cord (UC), has gained popularity. While mesenchymal stem cells (MSCs) derived from Wj show promise in restoring articular cartilage, they also have some limitations. Recent studies have indicated that exosomes isolated from acellular Wj may offer advantages under certain conditions. To investigate the anti-inflammatory properties of exosomes isolated from Wj in synoviocytes. Decellularization of Wj was performed using sterile umbilical cords obtained from patients. Next, the exosomes were isolated from Wj using ultracentrifugation. After characterizing the exosomes, they were co-cultured with inflammatory synovial fibroblast cells (HIG-82) for 24 hours. Then, the gene expression levels and protein contents of some important inflammatory mediators including metalloproteinase-13 (MMP-13), cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) were measured in the cells using real-time PCR and ELISA tests, respectively. The expression levels of MMP-13, COX-2, and iNOS genes were significantly reduced in the cultured cells treated with exosomes compared to untreated cells. Moreover, the content of MMP-13, COX-2, and iNOS proteins were significantly lower in the supernatant of the cultured cells compared to the control. Wj-derived exosomes exhibit notable anti-inflammatory properties, which can help mitigate inflammation in the synovial environment of joints. However, further research is required to fully understand their benefits and potential applications in treating osteoarthritis.

PU.1 regulates osteoarthritis progression via CSF1R in synovial cells

This study elucidates the molecular mechanisms driving osteoarthritis (OA) by focusing on the transcription factor PU.1's role in synovial cells, specifically macrophages and fibroblast-like synoviocytes (FLS). Analyzing OA-related synovial gene expression from the GEO database highlighted immune regulation pathways in OA. Using protein-protein interaction and the JASPAR database, we pinpointed essential genes in OA development. Synovial tissues from OA patients and controls revealed pronounced PU.1 and its target CSF1R presence. In a surgically induced OA mouse model with PU.1 and CSF1R knockdown, ChIP assays confirmed PU.1's binding to the CSF1R promoter. Dual luciferase reporter assays and immunohistochemistry validated PU.1's regulatory impact on CSF1R transcription. Combined analysis of microarrays GSE55235 and GSE206848 showed heightened PU.1 expression in OA, associated with immune regulation in macrophages. In vitro findings aligned with in vivo results, emphasizing PU.1's influence on macrophage polarization and FLS-induced inflammation. PU.1's direct activation of CSF1R transcription underpins its key role in OA progression. This research offers insights into OA's molecular basis, suggesting potential therapeutic targets.

Synovial Fluid White Blood Cell Count as a Potential Biomarker for the Clinical Severity of Knee Osteoarthritis: A Prospective Study

Knee osteoarthritis is categorized classically as a non-inflammatory arthropathy. However, there has been increasing evidence regarding the supplementary role of inflammation in the pathogenesis and disease progression of knee osteoarthritis. This study aims to identify a potential correlation between synovial fluid White Blood Cell (SF WBC) count and the severity of knee osteoarthritis clinical presentation. 200 knees (200 patients) were assessed through synovial fluid aspiration and cytology analysis for WBC count. All patients have filled out the Knee Injury and Osteoarthritis Outcome Score for clinical correlation. For the 200 knees, there was a statistically significant positive correlation between the severity of osteoarthritis clinical presentation as expressed by the KOOS and the synovial white blood cell count among the studied cases (p-value < 0.001). There was no statistically significant correlation found between the patient’s age, sex, or side and KOOS or synovial fluid white cell count. The clinical severity of knee osteoarthritis is directly correlated with increased synovial fluid white cell count and hence, SF WBCs may play a role in identifying and grading osteoarthritis clinical severity. This may raise the interest in identifying the role of using specific disease-modifying drugs that deal with the WBC function in cases of osteoarthritis along with other modalities.

Effect of Freeze-Thawing Treatment on Platelet-Rich Plasma Purified with Different Kits.

Osteoarthritis of the knee (OAK), a progressive degenerative disease affecting quality of life, is characterized by cartilage degeneration, synovial inflammation, and osteophyte formation causing pain and disability. Platelet-rich plasma (PRP) is an autologous blood product effective in reducing OAK-associated pain. PRP compositions depend on their purification. In clinical practice, PRP is typically administered immediately after purification, while cryopreserved PRP is used in research. Platelets are activated by freezing followed by release of their humoral factors. Therefore, PRP without any manipulation after purification (utPRP) and freeze-thawed PRP (fPRP) may differ in their properties. We purified leukocyte-poor PRP (LPPRP) and autologous protein solution (APS) to compare the properties of utPRPs and fPRPs and their effects on OAK target cells. We found significant differences in platelet activation and humoral factor content between utPRPs and fPRPs in both LPPRP and APS. Freeze-thawing affected the anti-inflammatory properties of LPPRP and APS in chondrocytes and synovial cells differed. Both utPRPs and fPRPs inhibited polarization toward M1 macrophages while promoting polarization toward M2 macrophages. Freeze-thawing specifically affected humoral factor production in macrophages, suggesting that evaluating the efficacy of PRPs requires considering PRP purification methods, properties, and conditions. Understanding these variations may enhance therapeutic application of PRPs in OAK.

Xuetongsu ameliorates synovial inflammatory hyperplasia in rheumatoid arthritis by inhibiting JAK2/STAT3 and NF-κB signaling pathways

Ethnopharmacological relevanceSynovial inflammatory hyperplasia is the key pathological process that leads to further joint damage in rheumatoid arthritis (RA) progress. Kadsura heteroclita (Roxb) Craib, also called Xuetong in Chinese Tujia ethnomedicine, is utilized for its medicinal properties, including promoting blood circulation, dispelling “wind evil”, and relieving “damp evil”. It has been used in the treatment of arthralgia and RA, within Tujia ethnomedicinal practices. Xuetongsu (XTS), the main component of Xuetong, has been shown to inhibit the proliferation of RA fibroblast-like synovial cells (RAFLS) cells. However, the molecular mechanism of XTS in RA treatment requires further investigation. Aim of the studyTo observe the therapeutic effect of XTS on synovial inflammatory hyperplasia in rheumatoid arthritis, focusing on its underlying molecular mechanisms involving the janus kinase 2 (JAK2)/transducer/activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-κB) signaling pathways. Materials and methodsProtein-protein interaction (PPI) and molecular docking were used to find the main targets of XTS treatment for RA. In lipopolysaccharide (LPS)-induced RAFLS and RAW264.7 cells in vitro models, the levels of inflammatory cytokines were analyzed using enzyme linked immunosorbent assay (ELISA), and the expression of JAK2, STAT3, and NF-κB signaling pathways, as well as cyclooxygenase-2 (COX-2), were analyzed through western blotting test. A hemolysis assay was used to certify the biosecurity of XTS. A model of adjuvant arthritis (AIA) was established in 40 male rats, and different doses of XTS were administered, followed by an automatic blood routine, ELISA assay, hematoxylin and eosin (H&E) staining, and radiological analysis of the effect of no XTS on blood cytokines, histological changes, and improvement of posterior paw bone destruction in AIA rats. The protein levels of inflammatory cytokines were analyzed by immunofluorescence, immunohistochemistry, or Western blot. Finally, H&E staining was used to detect the damage of XTS on the heart, liver, spleen, lung, and kidney of AIA rats. ResultsOur results demonstrate that XTS effectively inhibited LPS-induced inflammatory responses in RAFLS and RAW264.7 cells by modulating the JAK2/STAT3 and NF-κB signaling pathways. Moreover, XTS administration in the AIA rats model significantly ameliorated paw swelling. Histological analysis revealed that XTS also suppressed the inflammatory response in paw tissue by modulating the JAK2/STAT3 and NF-κB signaling pathways. Importantly, during the treatment, XTS exhibited excellent safety profiles, as it did not induce any abnormalities in blood routine parameters or cause organ damage in the rats. ConclusionsOur findings highlight XTS as a promising natural agent for inhibiting synovial hyperplasia in RA. XTS holds great potential as an unprecedented natural agent for developing novel therapeutic strategies to target synovial hyperplasia in RA.

Mitoregulin modulates inflammation in osteoarthritis: Insights from synovial transcriptomics and cellular studies

Osteoarthritis is a prevalent musculoskeletal disease that involves cartilage degradation, subchondral bone remodeling, and synovial inflammation and ultimately causes physical disability. Common risk factors for osteoarthritis include age, sex, obesity, and genetic predispositions. Treatment includes nonpharmaceutical and pharmacological approaches; however, disease-modifying osteoarthritis drugs remain undeveloped. We aimed to identify key regulatory factors underlying the etiology of osteoarthritis. We studied alterations of the inflammatory responses after manipulating the expression of MTLN, which we selected after sequencing and transcriptomics of the patients’ synovial tissues. MTLN expression was increased in synovial tissues of patients and in SW982 human synovial sarcoma cells following inflammatory stimuli. We found that MTLN overexpression or knockout respectively decreased or increased expression of the inflammation-associated genes, including IL-6, IL-8, and TNF-α. Thus, high levels of MTLN in osteoarthritis may protect tissues against excessive inflammation, thereby offering therapeutic potentials.

Aspirations Dashed: Conventional Synovial Fluid Analysis Is Superior to Synovial Fluid and Blood Neutrophil-to-Lymphocyte Ratios in Diagnosing Pediatric Septic Arthritis of the Hip and Knee.

Recent research suggests that synovial fluid neutrophil-to-lymphocyte ratio (SF-NLR) is a superior diagnostic for pyogenic septic arthritis (SA) in adults compared with synovial fluid white blood cell count (SF-WBC) ≥50,000 cells/μL or ≥90% polymorphonuclear leukocytes (SF-%PMN). Other research also indicates that the neutrophil-to-lymphocyte ratio in the blood (B-NLR) may be of diagnostic significance. However, it is not known whether these findings extend to the pediatric population. Medical records at a large urban tertiary-care children's hospital were queried for emergency department visits between 2012 and 2023, where synovial fluid (SF) analysis was performed to evaluate for SA of the hip or knee. Patients 18 years old and above were excluded. The "conventional composite test" (CCT) for SA was considered positive if SF analysis showed any of the following: (1) SF-WBC ≥50,000 cells/μL, (2) ≥90% PMNs, or (3) organisms reported on gram stain. Patients with aspirate and/or operating room (OR) cultures (or supplemental testing, ie, nucleic acid identification) revealing an offending organism were considered to have culture-positive septic arthritis (CPSA). The remaining patients were considered culture-negative (CN). Serum and SF test data were analyzed to assess their diagnostic utility in identifying CPSA. Receiver operating characteristic (ROC) curves were examined to compare the predictive value of SF-NLR and B-NLR versus conventional indicators of SA. A total of 394 patients met the inclusion criteria. In all, 58.6% (n=231) were male, 67.5% (n=266) involved the knee, and 20.1% (n=79) had CPSA. Those with CPSA had higher ESR and CRP compared with CN patients (P<0.01). Bivariate testing did not show a difference in SF-NLR or B-NLR between those with CPSA and CN patients (P=0.93 and 0.37, respectively). The CCT showed 91% sensitivity and 35% specificity using conventional thresholds. ROC analysis showed that SF-WBC was superior to SF-NLR and B-NLR in the diagnosis of CPSA (AUC=0.71 vs. 0.50 and 0.53, respectively; both P<0.01). Among CCT (+) patients who ended up culture negative, Lyme testing was positive in 48.8% (100/205). In contrast to adults, SF-NLR and B-NLR were not found to be strong diagnostic indicators of SA of the hip or knee in pediatric patients. This may be because competing diagnoses in children come with systemic inflammatory responses similar to that seen in pyogenic SA, while noninfectious conditions that might represent the major alternate diagnoses in adults do not increase systemic inflammatory markers as significantly. Given the high incidence of Lyme disease seen among patients in this study, this topic should be further studied at pediatric centers outside Lyme-endemic areas to better understand the generalizability of these findings. Despite excitement regarding SF-NLR and B-NLR as diagnostics for adult SA, these criteria appear less useful in the diagnosis of pyogenic SA in pediatric patients in Lyme-endemic areas.

NAT10 promotes synovial aggression by increasing the stability and translation of N4-acetylated PTX3 mRNA in rheumatoid arthritis

ObjectiveRecent studies indicate that N-acetyltransferase 10 (NAT10)-mediated ac4C modification plays unique roles in tumour metastasis and immune infiltration. This study aimed to uncover the role of NAT10-mediated ac4C in fibroblast-like...

Effects of polysaccharide from Pueraria lobata on osteoarthritis in rats

The effects of Pueraria lobata polysaccharide (PPL-1) on osteoarthritis (OA) disease were comprehensively evaluated by using chondrocytes and synoviocytes extracted from the joints of SD rats based on in vitro cell experiments and by establishing pathological models of OA rats. The results showed that concentrations of 1.25–10 and 0.2–1.6 μg/mL, PPL-1 did not inhibit or promote chondrocytes and synoviocytes in vitro. However, at concentrations of 1.25–10 and 0.2–1.6 μg/mL, it can promote cartilage and synovial membrane cells after LPS stimulation of cell activity and inhibite LPS-induced apoptosis. The results of animal experiments showed that PPL-1 can reduce the symptoms of joint swelling in OA rats, decrease the production of serum inflammatory cytokines TNF-α, IL-1β, and IL-6, and slow down the occurrence of inflammation. Therefore, from the perspective of symptoms, inflammatory factors and pathology, PPL-1 has therapeutic effects on OA rats and alleviates the development of inflammation. It indicated that PPL-1 has the potential to be developed into an OA therapeutic drug with anti-inflammatory properties that protects and activates chondrocytes.

Discovery of CYP2E1 as a novel target in rheumatoid arthritis and validation by a new specific CYP2E1 inhibitor

Considerable evidence indicates that CYP2E1 is associated with a variety of inflammatory diseases. Here we evaluated CYP2E1 as a potential therapeutic target for rheumatoid arthritis (RA) and established the protective effect of a new CYP2E1 inhibitor. Gene-expression datasets were used to analyze the change in expression of CYP2E1 in RA patients; CYP2E1 activity in collagen-induced arthritis (CIA) rats was determined by HPLC. We further evaluated the protective effects of Cyp2e1 knockout and a CYP2E1-specific inhibitor, Q11, synthesized by our group, in CIA and adjuvant-induced arthritis (AIA) rats. The expression of CYP2E1 in synovial tissue was elevated in RA patients and in CIA rats and the activity of CYP2E1 in vivo and in vitro in CIA rats was greater than that of controls. Cyp2e1 knockout significantly reduced the incidence of CIA and alleviated the severity of symptoms. Treatment with different doses of Q11 decreased paw thickness, volume and arthritis scores and reduced the serum levels of IL‐6, TNF‐α, IL‐1β and MDA, and increased the level of GSH in CIA rats. A similar inhibitory effect was exhibited for Q11 in the AIA rats. Moreover, Q11 significantly impeded proliferation, migration, and invasion of human rheumatoid arthritis synovial fibroblasts cells. Q11 decreased the release of ROS and enhanced Nrf2 nuclear translocation and HO-1 expression in the cell nucleus. Overall, our results indicated that CYP2E1 may be a new target for RA and Q11 has potential protective effects against RA by reducing oxidative stress and opposing the inflammatory response via the ROS/Nrf2/HO-1 signaling pathway.

Discovery of CW-3308 as a Potent, Selective, and Orally Efficacious PROTAC Degrader of BRD9.

The bromodomain-containing protein BRD9 has emerged as an attractive therapeutic target. In the present study, we successfully identified a number of highly potent BRD9 degraders by using two different cereblon ligands developed in our laboratory. Further optimization led to the discovery of CW-3308 as a potent, selective, and orally bioavailable BRD9 degrader. It displayed degradation potency (DC50) < 10 nM and efficiency (Dmax) > 90% against BRD9 in the G401 rhabdoid tumor and HS-SY-II synovial sarcoma cell lines and had a high degradation selectivity over BRD7 and BRD4 proteins. CW-3308 achieved 91% of oral bioavailability in mice. A single oral dose efficiently reduced the BRD9 protein by >90% in the synovial sarcoma HS-SY-II xenograft tumor tissue. Oral administration effectively inhibited HS-SY-II xenograft tumor growth in mice. CW-3308 is a promising lead compound for further optimization and extensive evaluation for the treatment of synovial sarcoma, rhabdoid tumor, and other BRD9-dependent human diseases.

Synovial expression of glucocorticoid receptor parallels fibroblast activation in patients with rheumatoid arthritis.

Hypocortisolemia is associated with increased expression of NR3C1 (glucocorticoid receptor, GR) in blood cells. As endogenous cortisol production is decreased in some RA patients, we tested the hypothesis that GR may be aberrantly expressed in rheumatoid synovium. We defined the cellular pattern of NR3C1 synovial expression using human and mouse single-cell RNA-sequencing data. Bulk synovial RNA-sequencing data from early (n = 57) or established (n = 94) RA were compared to osteoarthritis (n = 22) and healthy synovium (n = 28). GR was expressed in all synovial cell types in both human and experimental arthritis. GR synovial expression, as well as 11β-HSD1/11β-HSD2 enzyme ratio, were higher in RA than healthy and osteoarthritic tissue, regardless of disease duration or treatment. Given that GR expression varied across samples, we searched for differences between RA patients with higher versus lower GR expression. Indeed, the synovial transcriptome of RA patients with high versus low GR expression (1st quartile, 30,517 ± 4876 vs. 4th quartile, 19,382 ± 2523 normalized counts) was enriched for proinflammatory gene-sets, including 'inflammatory response', 'IFN-γ response' and 'IL6/JAK/STAT3 signalling'. High synovial GR expression was also associated with increased JAK2 and PTPRK expression, denoting activation of the proinflammatory sublining fibroblasts. In contrast, low GR expression was associated with increased COMP and COL6A2 expression, denoting a resting synovial state. GR is overexpressed in the synovium of some RA patients in association with proinflammatory gene expression and activated sublining fibroblast status. Further studies should examine whether GR overexpression may act as a compensatory mechanism sensitizing synovial tissue to glucocorticoid action in RA.