Project description:Osteoarthritis (OA) is a heterogeneous disease that is extremely hard to cure owing to its complex regulation network of pathogenesis, especially cartilage degeneration. FBXO21 is a subunit of ubiquitin E3 ligases that degrades P-glycoprotein and EID1 by ubiquitination and activates the JNK and p38 pathways; however, its role in OA remains unknown. Here, the main objective of this study was to evaluate the potential effects and mechanism of FBXO21 in OA degeneration, we revealed that FBXO21 is upregulated in the cartilage of patients with OA, aging, and monosodium iodoacetate-induced OA rats, and chondrocytes treated with interleukin-1β, tumor necrosis factor-α, and lipopolysaccharide. Moreover, the in vivo and in vitro knockdown of FBXO21 suppressed OA-related cartilage degeneration, as evidenced by activated autophagy, upregulated anabolism, alleviated apoptosis, and downregulated catabolism. In contrast, its overexpression promoted OA-related cartilage degeneration. In addition, using mass spectrometry and co-immunoprecipitation assay, we demonstrated that the downstream mechanism of FBXO21 inhibits autophagy by interacting with and phosphorylating ERK. Furthermore, FBXO21 alleviated anabolism and enhanced apoptosis and catabolism by inhibiting autophagy in rat chondrocytes. Interestingly, for its upstream mechanism, JUNB promoted FBXO21 expression by directly targeting the FBXO21 promoter, thus further accelerating cartilage degeneration in SW1353 cells and rat chondrocytes. Overall, our findings reveal that the JUNB-FBXO21-ERK axis regulates OA apoptosis and cartilage matrix metabolism by inhibiting autophagy. Therefore, FBXO21 is an attractive target for regulating OA pathogenesis, and its knockdown may provide a novel targeted therapy for OA.
Project description:Osteoarthritis, a chronic degenerative cartilage disease, is the leading cause of movement disorders among humans. Although the specific pathogenesis and associated mechanisms remain unclear, oxidative stress-induced metabolic imbalance in chondrocytes plays a crucial role in the occurrence and development of osteoarthritis. In this study, a trimanganese tetroxide (Mn3 O4 ) nanozyme with superoxide dismutase (SOD)-like and catalase (CAT)-like activities is designed to reduce oxidative stress-induced damage and its therapeutic effect is investigated. In vitro, Mn3 O4 nanozymes are confirmed to reprogram both the imbalance of metabolism in chondrocytes and the uncontrolled inflammatory response stimulated by hydrogen peroxide. In vivo, a cross-linked chondroitin sulfate (CS) hydrogel is designed as a substrate for Mn3 O4 nanozymes to treat osteoarthritis in mouse models. As a result, even in the early stage of OA (4 weeks), the therapeutic effect of the Mn3 O4 @CS hydrogel is observed in both cartilage metabolism and inflammation. Moreover, the Mn3 O4 @CS hydrogel maintained its therapeutic effects for at least 7 days, thus revealing a broad scope for future clinical applications. In conclusion, these results suggest that the Mn3 O4 @CS hydrogel is a potentially effective therapeutic treatment for osteoarthritis, and a novel therapeutic strategy for osteoarthritis based on nanozymes is proposed.
Project description:Cryptotanshinone (CTS) has emerged as an anti-inflammatory agent in osteoarthritis (OA). However, the molecular mechanism underlying its potent therapeutic effect on OA remains largely unknown. MicroRNAs (miRNAs) act as crucial regulators in maintaining cartilage homeostasis. To investigate whether CTS protects against developing OA through regulation of miRNAs, we examined the potential CTS-mediated miRNA molecules using microarray analysis. We found that CTS significantly promoted miR-106a-5p expression in chondrocytes. Using the OA mouse model created by anterior cruciate ligament transection, we revealed that intra-articular injection of miR-106a-5p agomir attenuated OA. In addition, miR-106a-5p inhibited GLI-similar 3 (GLIS3) production by directly targeting the 3' untranslated region. CTS promoted miR-106a-5p expression through recruitment of a member of the paired box (PAX) family of transcription factors, PAX5, to the miR-106a-5p promoter. Inhibition of PAX5 mimicked the effect of miR-106a-5p and abolished the CTS ability to regulate miR-106a-5p expression. In OA patients, miR-106-5p is downregulated which is accompanied by downregulation of PAX5 and upregulation of GLIS3. Collectively, these data highlight that the PAX5/miR-106a-5p/GLIS3 axis acts as a novel pleiotropic regulator in CTS-mediated OA cartilage protection, suggesting that miR-106a-5p and PAX5 activation and GLIS3 inhibition might be useful and attractive for therapeutic strategies to treat OA patients.
Project description:Zhuangguguanjie formulation (ZG) can provide noticeable relief from joint pain in patients suffering from knee osteoarthritis (OA). However, the underlying mechanism has not been fully described. Male C57BL/6 mice were administered either ZG or normal saline (NS) following surgical destabilization of the medial meniscus (DMM). At weeks 4, 6 and 8 (post-surgery), knee joints were harvested and assessed with Safranin-O staining. Blood serum was collected and tested. In vitro analysis was carried out to evaluate the effects of ZG on the expression of the OA-related genes. DMM mice indicated reduced cartilage destruction and lower blood serum biomarkers of OA (COMP1 and CTX-1) following ZG treatment. Moreover, the femoral condyle and tibial plateau histological scores were significantly reduced following ZG treatment of the DMM mice. ZG could markedly downregulate the expression of OA-related genes namely, ADAMTS5, MMP3 and MMP13, while it simultaneously upregulated collagen II as demonstrated by in vitro assays. Moreover, chondrocyte apoptosis was significantly decreased following ZG treatment. These results may be caused by the up-regulation of p-AKT expression levels, since the anti-apoptotic effects of ZG can be blocked by treatment with an AKT inhibitor. ZG is capable of preventing and/or reducing the progression of OA by inhibiting chondrocyte apoptosis via the p-AKT/Caspase 3 pathway.
Project description:To assess the direct downstream targets of HPIP, a genome-wide ChIP-seq profiling was performed. The ChIP-seq data was examined by the quality evaluation. The results demonstrated that of significant ChIP-seq peaks for HPIP, 59% of them occurred at intronic and intergenic sites We found HPIP was closely correlated with the cartilage development.
Project description:To underly the potential downstream transcriptional regulation of HPIP that could account for cartilage and skeletal development. RNA-seq analysis were performed in HPIP knockout and control primary chondrocytes.Among the 1271 significantly differentially expressed genes, transcripts for 486 (7%) of them were upregulated while transcripts for 785 (11%) were downregulated in HPIP knockout chondrocytes compared to the controls. We found HPIP was closely correlated with the cartilage development.
Project description:ObjectivesCircular RNAs (circRNAs) are noncoding RNAs that compete against other endogenous RNA species, such as microRNAs, and have been implicated in many diseases. In this study, we investigated the role of a new circRNA (circSLC7A2) in osteoarthritis (OA).Materials and methodsThe relative expression of circSLC7A2 was significantly lower in OA tissues than it was in matched controls, as shown by real-time quantitative polymerase chain reaction (RT-qPCR). Western blotting, RT-qPCR and immunofluorescence experiments were employed to evaluate the roles of circSLC7A2, miR-4498 and TIMP3. The in vivo role and mechanism of circSLC7A2 were also conformed in a mouse model.ResultscircSLC7A2 was decreased in OA model and the circularization of circSLC7A2 was regulated by FUS. Loss of circSLC7A2 reduced the sponge of miR-4498 and further inhibited the expression of TIMP3, subsequently leading to an inflammatory response. We further determined that miR-4498 inhibitor reversed circSLC7A2-knockdown-induced OA phenotypes. Intra-articular injection of circSLC7A2 alleviated in vivo OA progression in a mouse model of anterior cruciate ligament transection (ACLT).ConclusionsThe circSLC7A2/miR-4498/TIMP3 axis of chondrocytes catabolism and anabolism plays a critical role in OA development. Our results suggest that circSLC7A2 may serve as a new therapeutic target for osteoarthritis.
Project description:Osteoarthritis (OA) is a degenerative disease of synovial joints characterized by progressive loss of articular cartilage, subchondral bone remodeling, and intra-articular inflammation with synovitis that results in chronic pain and motor impairment. Despite the economic and health impacts, current medical therapies are targeted at symptomatic relief of OA and fail to alter its progression. Given the complexity of OA pathogenesis, we hypothesized that a combinatorial gene therapy approach, designed to inhibit inflammation with interleukin-1 receptor antagonist (IL-1Ra) while promoting chondroprotection using lubricin (PRG4), would improve preservation of the joint compared to monotherapy alone. Employing two surgical techniques to model mild, moderate and severe posttraumatic OA, we found that combined delivery of helper-dependent adenoviruses (HDVs), expressing IL-1Ra and PRG4, preserved articular cartilage better than either monotherapy in both models as demonstrated by preservation of articular cartilage volume and surface area. This improved protection was associated with increased expression of proanabolic and cartilage matrix genes together with decreased expression of catabolic genes and inflammatory mediators. In addition to improvements in joint tissues, this combinatorial gene therapy prolonged protection against thermal hyperalgesia compared to either monotherapy. Taken together, our results show that a combinatorial strategy is superior to monotherapeutic approaches for treatment of posttraumatic OA.