Study of the mechanism underlying hsa-miR338-3p downregulation to promote fibrosis of the synovial tissue in osteoarthritis patients.

Osteoarthritis (OA) is a degenerative joint disease characterized by the degradation of joint cartilage, the formation of osteophyma at joint margins, and synovial changes. Whereas lesions of the joint cartilage were the key point of the research and treatment of osteoarthritis before, a recent study showed that the synovium plays a crucial role in the pathological progress of OA. The inflammatory environment in the joints of OA patients always results in the overactivation of fibroblast-like synoviocytes (FLSs), which produce a multitude of inflammatory factors and media, not only leading to the degradation and injury of the cartilage tissue and promoting the development of osteoarthritis but also resulting in synovial fibrosis and joint stiffness. Therefore, the synovium has attracted increasing attention in the research of OA, and the study of the mechanism of activation of FLSs and the fibrosis of joint synovium may shed new light on OA treatment. By using high-throughput screening, we have identified that hsa-miR338-3p is significantly downregulated in the synovial tissue and joint effusion from OA patients. A functional study showed that overexpression of hsa-miR338-3p in the FLSs inhibited the TGF-ß1-induced overactivation of the TGF-ß/Smad fibrosis regulation pathway by suppressing TRAP-1 expression and thus reducing the TGF-ß1-induced activation of the FLSs and the expression of vimentin and collagen I, two fibrosis markers. Meanwhile, a mechanism study also showed that the upregulation of hsa-miR338-3p reduced Smad2/3 phosphorylation by suppressing TRAP-1 and thus inhibited the TGF-ß/Smad pathway and TIMP1, a downstream protein. The present study, for the first time, illustrates the role of hsa-miR338-3p in synovial fibrosis in OA patients and the related mechanism, which is of importance to the treatment of OA and its complications by targeting the FLSs and synovial tissue. Hsa-miR338-3p not only has the potential to be a target for the gene therapy of OA but also has the potential to be a new marker for the diagnosis of clinical progression in OA patients.

Antitumor activity of dobutamine on human osteosarcoma cells.

Dobutamine has been widely used for the treatment of heart failure and cardiogenic shock since the 1970s. Osteosarcoma is the most commonly observed malignant bone tumor in children. Currently, there are no effective drugs for the treatment of osteosarcoma. In the present study, the potential anticancer activity of dobutamine on human osteosarcoma cells was examined. Human osteosarcoma MG-63 cells were treated with dobutamine at various concentrations and for various incubation times. The inhibition of cell growth by dobutamine was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry was utilized to evaluate the effect of dobutamine on cell apoptosis and the cell cycle. Furthermore, the expression levels of caspase-3 and caspase-9 were assessed by western blot analysis. The influence of dobutamine on cancer cell migration and invasion was additionally evaluated using wound-healing assay and the Boyden Chamber migration method. Dobutamine significantly inhibited the growth of MG-63 cells at a concentration of 10 µM or higher when incubated for 12 h or longer (P=0.023). Dobutamine augmented cell apoptosis and arrested the cell cycle in the G2/M phase. Western blot analysis revealed that dobutamine induces expression of caspase-3 and caspase-9. In addition, the invasiveness and migration of MG-63 cells was inhibited by dobutamine in a concentration-dependent manner. The results of the present study may lead to novel applications for dobutamine in the treatment of osteosarcoma.

Spatiotemporal pattern of TRAF3 expression after rat spinal cord injury.

TNF receptor associated factor 3 (TRAF3), a member of the TRAF family of intracellular signaling proteins, can directly influence the phosphorylation status and activation of c-Jun N-terminal kinase, participating in CD40-induced apoptosis in carcinoma. However, its expression profile and function are still unclear in spinal cord injury (SCI). In this study, we performed an acute spinal cord contusion injury model in adult rats and detected the dynamic change patterns of TRAF3 expression in spinal cord. Western blot and immunohistochemistry revealed a striking upregulation of TRAF3 after SCI. Double immunofluorescence staining prompted that TRAF3 immunoreactivity was found in neurons rather than astrocytes. Moreover, co-localization of TRAF3/active caspase-3 was detected in neuronal nuclei. To further investigate the function of TRAF3, a neuronal cell line PC12 was employed to establish an apoptosis model in vitro. We analyzed the association of TRAF3 with active caspase-3 on PC12 cells by western blot and immunofluorescent labeling, which was parallel with the data in vivo. Additionally, knocking TRAF3 down with siRNA demonstrated the probable pro-apoptotic role of TRAF3 in the process of neuronal apoptosis. To summarize, we firstly uncover the temporal and spatial expression changes of TRAF3 in SCI. Our data suggest that TRAF3 might be implicated in central nervous system pathophysiology after SCI.

Effects of exercise therapy on knee joint function and synovial fluid cytokine levels in patients with knee osteoarthritis.

The aims of this study were to observe the effect of exercise therapy on the function of the knee joint and the levels of cytokines and cytokine-related genes, specifically tumor necrosis factor-α (TNF-α), high sensitivity C-reactive protein (hs-CRP) and matrix metalloproteinase-3 (MMP-3), in the synovial joints of patients with knee osteoarthritis (KOA) and to explore its mechanism of action. A total of 100 KOA patients were divided into a treatment group (n=50) and a control group (n=50) according to the order of admission. The patients in the treatment group were treated with diclofenac sodium combined with exercise therapy and the patients in the control group were treated with diclofenac sodium only. The function of the knee joint and the therapeutic efficacy was evaluated and the TNF-α, hs-CRP and MMP-3 levels in the synovial fluid were measured following 4 weeks of treatment. The results revealed that the knee joint index score and the TNF-α, hs-CRP and MMP-3 levels in the synovial fluid decreased significantly in the KOA patients of the two groups following treatment (P<0.05). Compared with the control group, the knee joint index score and the TNF-α, hs-CRP and MMP-3 levels in the synovial joints were lower and the therapeutic efficacy was increased in the patients of the treatment group (P<0.05). In brief, exercise therapy may decrease cytokine and cytokine-related gene levels in the synovial fluid and inhibit inflammatory factor-mediated cartilage degradation in KOA patients, thus, effectively improving the clinical symptoms of KOA.