Celastrol ameliorates osteoarthritis via regulating TLR2/NF-κB signaling pathway.

Objectives: Osteoarthritis (OA) is a joint disease characterized by degeneration of joint cartilage and is a significant cause of severe joint pain, physical disability, and impaired quality of life in the aging population. Celastrol, a Chinese herbal medicine, has attracted wide interests because of its anti-inflammatory effects on a variety of diseases. This study aimed to investigate the effect of celastrol on OA as well as the mechanisms in vivo and in vitro. Methods: A rat knee OA model was established using "medial collateral ligament transection (MCLT) + partial meniscectomy (pMMT)". Eight weeks after surgery, the OA rats started to receive intra-articular injection of celastrol (1 mg/kg) once a week. Safranin O-fast green (S&F) and hematoxylin and eosin (H&E) staining were used to estimate histopathological changes. Micro-CT was used to evaluate bone volume of the subchondral bone of the knee joint. Chondrocytes were isolated from the knee cartilage of rats and OA patients. Enzyme linked immunosorbent assay (ELISA), Western Blot (WB), Polymerase Chain Reaction (PCR), and Immunohistochemistry (IHC) were used to detect the expression of inflammatory factors and stromal proteins, respectively. Results: We found that celastrol treatment significantly delayed the progression of cartilage damage with a significant reduction in osteophyte formation and bone resorption in OA rat model. In IL-1ß-stimulated rat chondrocytes, celastrol significantly suppressed the production of inflammatory factors such as cyclooxygenase-2 (COX2), interleukin-6 (IL-6), and prostaglandin E2 (PEG2), and reduced IL-1ß-induced matrix degradation by down-regulating the expression of matrix metalloproteinase 13 (MMP13). In addition, we found that toll-like receptor 2 (TLR2) was up-regulated in OA patients and rat knee OA models, while celastrol inhibited TLR2 signal and its downstream nuclear factor-kappa B (NF-κB) phosphorylation. Conclusion: In summary, celastrol may improve OA by inhibiting the TLR2/NF-κB signaling pathway, which provides innovative strategies for the treatment of OA.

Mesenchymal stem cell transplantation alleviates Sjögren's syndrome symptoms by modulating Tim-3 expression.

Mesenchymal stem cell (MSC) transplantation has been proven to be an effective treatment for Sjögren's syndrome (SS) to improve salivary gland pathology and exocrine function, but the mechanism remains unclear. A recently reported inhibitory receptor, Tim-3, also appears to be closely related to autoimmune diseases. Here, we aimed to explore the roles of Tim-3 in the pathogenesis of SS and MSC treatment. The results showed that Tim-3 was downregulated in T cells of SS patients and nonobese diabetic (NOD) mice, which is correlated with SS pathogenesis. MSC transplantation ameliorated SS-like symptoms and pathological changes in the submandibular glands with modulated Tim-3 expression, resulting in attenuation of localized inflammation, fibrosis, and epithelial-mesenchymal transition. Furthermore, Tim-3 is crucial for the inhibitory effect of MSCs on PBMC proliferation in vitro. Therefore, our work has demonstrated that MSC transplantation effectively mitigates the pathological changes of SS by regulating Tim-3 expression, which provides a novel mechanism of MSC treatment and indicates a brand-new perspective of the combination of inhibitory-receptor-targeted treatment and MSC therapy in SS.

Coexpression network analysis coupled with connectivity map database mining reveals novel genetic biomarkers and potential therapeutic drugs for polymyositis.

OBJECTIVE: Polymyositis (PM) is a chronic autoimmune connective tissue disease whose pathogenic mechanisms are unclear. This study aimed to identify the main genes and functionally enriched pathways involved in PM using weighted gene coexpression network analysis (WGCNA). METHODS: To identify the candidate genes of PM, microarray datasets GSE128470, GSE3112, GSE39454 and GSE125977 were obtained from the Gene Expression Omnibus database. The gene network of GSE128470 was constructed, and WGCNA was used to divide genes into different modules. Subsequently, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were applied to the most PM-related modules. The datasets were used to verify the expression profile and diagnostic capabilities of the hub genes. Additionally, gene set enrichment analysis (GSEA) was carried out. Moreover, gene signatures were then used as a search query to explore the connectivity map (CMap). RESULTS: A weighted gene coexpression network was constructed, and the genes were divided into 66 modules. The enriched functions and candidate pathway modules included interferon-γ, type I interferon, cellular response to interferon-γ, neutrophil activation, neutrophil degranulation, neutrophil-mediated immunity and neutrophil activation involved in the immune response. A total of 22 hub genes were identified. The Mann-Whitney U test was performed on these 22 genes using the three datasets of muscle samples and one dataset of whole blood samples, and two genes significantly differentially expressed in all datasets were obtained: VCAM1 and LY96. Receiver operating characteristic curve analysis determined that VCAM1 and LY96 gene expression can distinguish PM from healthy controls (the area under the curve [AUC] was greater than 0.75). Logistic regression analysis was performed on the combination of LY96 and VCAM1. The accuracy, sensitivity, specificity, and AUC of the combination reached 1.0. GSEA of VCAM1 and LY96 revealed their relation to 'inflammatory response', 'TNF-α signalling via NF-κB', 'complement' and 'myogenesis'. CMap research revealed a few compounds with the potential to counteract the effects of the dysregulated molecular signature in PM. CONCLUSIONS: We used WGCNA to observe all aspects of PM, which helped to elucidate the molecular mechanisms of PM onset and progression and provide candidate targets for the diagnosis and treatment of PM. Key Points • Four microarray datasets were analysed in patients with polymyositis and healthy controls, and VCAM1 and LY96 were significant genes in all datasets. • GSEA of VCAM1 and LY96 revealed that they were mainly related to 'inflammatory response', 'TNF-α signalling via NF-κB', 'complement' and 'myogenesis'. • CMap found a few compounds such as dimethyloxalylglycine and HNMPA-(AM)3 with the potential to counteract the effects of the dysregulated molecular signature in PM.