PP2 alleviates the progression of osteoarthritis by inhibiting Wnt/ß-catenin and activating TGF-ß/Smad signaling.

OBJECTIVE: We aimed to explore the effect and mechanism of the Src inhibitor PP2 on osteoarthritis (OA) progression. METHODS: The protein expressions of Src, p-Src (y418) and p-FAK in normal and OA human chondrocytes were detected by immunofluorescence (IF) analysis. Chondrocytes from the femur and tibial plateau of 3-day-old mice were extracted and inoculated into 6-well plates. The chondrocytes were co-cultured with IL-1ß and different doses of PP2, and then the degeneration of extracellular matrix was analyzed. A mouse OA model was induced by destabilizing medial meniscectomy of the right knee. Two weeks after the operation, different doses of PP2 were injected intraperitoneally. The drug was given three times a week for 6 weeks, and then the mice were sacrificed. Histopathological, IF and immunoblotting analyses were used to detect key OA catabolic markers and protein expression and related signaling. RESULTS: The levels of Src, p-Src (y418) and p-FAK in the knee cartilage tissue of patients with OA were abnormally increased. After chondrocytes were co-treated with IL-1ß and different doses of PP2, the results showed that PP2 reduced the abnormal increase of ß-catenin, p-ß-catenin and other proteins induced by IL-1ß, and reversed the decrease of p-Smad3, aggrecan and collagen Ⅱ protein levels. Meanwhile, intraperitoneal injection of PP2 in vivo significantly reduced the degeneration of articular cartilage in the OA mouse model. CONCLUSION: Our data indicate that targeting Src with PP2 protected against cartilage destruction in an OA mouse model by inhibiting Wnt/ß-catenin and activating TGF-ß/Smad signaling, suggesting that Src may be a potential therapeutic target for OA treatment.

miRNA-429 suppresses osteogenic differentiation of human adipose-derived mesenchymal stem cells under oxidative stress via targeting SCD-1.

[This retracts the article DOI: 10.3892/etm.2019.8246.].

miRNA-429 suppresses osteogenic differentiation of human adipose-derived mesenchymal stem cells under oxidative stress via targeting SCD-1.

Role of microRNA-429 (miRNA-429) in osteogenic differentiation of hADMSCs was elucidated to explore the potential mechanism. Serum level of miRNA-429 in osteoporosis patients and controls was determined by quantitative real-time polymerase chain reaction (qRT-PCR). After H2O2 induction in hADMSCs, cell viability and reactive oxygen species (ROS) level were determined by cell-counting kit (CCK-8) assay and flow cytometry, respectively. Alkaline phosphatase (ALP) activity in H2O2-induced hADMSCs was also detected. The binding condition between miRNA-429 and SCD-1 was verified by dual-luciferase reporter gene assay. Relative levels of osteogenesis-related genes influenced by SCD-1 and miRNA-429 were detected by qRT-PCR. Furthermore, regulatory effects of SCD-1 and miRNA-429 on ALP activity and calcification ability of hADMSCs were evaluated. miRNA-429 was significantly upregulated in serum of osteoporosis patients. During the process of osteogenesis differentiation, H2O2 induction gradually upregulated miRNA-429 in hADMSCs. Overexpression of miRNA-429 markedly reduced ALP activity. Subsequent dual-luciferase reporter gene assay verified that miRNA-429 could bind to SCD-1 and negatively regulated its protein level in hADMSCs. SCD-1 was obviously downregulated in the osteogenesis differentiation of hADMSCs under oxidative stress. Moreover, silencing of SCD-1 suppressed expression of osteogenesis-related gene, ALP activity and calcification ability. Notably, SCD-1 knockdown partially reversed the regulatory effect of miRNA-429 on the osteogenic differentiation of hADMSCs. miRNA-429 suppresses the osteogenic differentiation of hADMSCs under oxidative stress via downregulating SCD-1.