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Aims To investigate the effect of dencichine on osteoclastogenesis in vivo and in vitro. Methods RANKL-induced osteoclastogenesis were treated with different concentrations of dencichine. Pit forming assays were applied to evaluate the degree of bone resorption. Osteoclastogenic markers were detected by real-time quantitative PCR (RT-qPCR) and Western blot. Micro CT was conducted to investigate the effects of dencichine on osteoclastogenesis in ovariectomized (OVX) mice. Results Dencichine suppressed osteoclastogenesis through the inhibition of phosphorylation of p65, p50 (NF-κB pathway), p38, ERK and JNK (MAPKs pathway) in vitro. Furthermore, dencichine inhibited the function of osteoclasts in a dose-dependent manner. In addition, the expression levels of the nuclear factor of activated T cells 1 (NFATc1) and osteoclastogenesis markers were decreased by dencichine, including MMP-9, Cathepsin K (CTSK), Tartrate-Resistant Acid Phosphatase (TRAP), C-FOS, dendritic cell specific transmembrane protein (DC-STAMP). In vivo data proved that dencichine alleviated ovariectomy-induced bone loss and osteoclastogenesis in mice. Conclusion Our results demonstrate that dencichine alleviates OVX-induced bone loss in mice and inhibits RANKL-mediated osteoclastogenesis via inhibition of NF-κB and MAPK pathways in vitro, suggesting that dencichine might serve as a promising candidate for treatment of bone loss diseases, including PMOP and rheumatoid arthritis.

Osteoporosis poses a threat to human health worldwide. To date, there have been few studies regarding targeted treatment of osteoporosis. We aimed to identify the possible molecular mechanism of circular RNA (circ)_0062582 in osteogenic differentiation, and the interactions among circ_0062582, microRNA-145 (miR-145) and core-binding factor subunit β (CBFB). The proliferation of human bone marrow mesenchymal stem cells (hBMSCs) was tested with a cell counting kit-8 assay. Circ_0062582, miR-145 and CBFB were overexpressed by transient transfection. Dual-luciferase reporter assay system was used to analyze the combination among circ_0062582, miR-145 and CBFB. Additionally, the levels of circ_0062582, miR-145, CBFB, osterix (OSX), osteocalcin (OCN) and collagen type 1 (COL1) were detected by means of RT-qPCR or western blot analysis. Alkaline phosphatase and Alizarin red stainings were performed to analyze the degree of osteogenic differentiation under the control of circ_0062582, miR-145 and CBFB. The results demonstrated that circ_0062582 level was notably elvated during osteogenic differentiation of hBMSCs. Circ_0062582 overexpression significantly promoted osteogenic differentiation and upregulated the levels of osteogenic differentiation-related proteins, including OSX, OCN and COL1. In addition, miR-145, which was identified as the target gene of circ_0062582, could specifically target CBFB 3′-UTR regions. Next, these changes caused by the overexpression of circ_0062582 were reversed following the addition of miR-145 mimic. Following overexpression of CBFB, osteogenic differentiation was increased. In summary, these results demonstrated that the role of circ_0062582 in osteoporosis is mediated through regulating the expression level of CBFB via miR-145., GRAPHICAL ABSTRACT

Background Ultra-high molecular weight polyethylene (UHMWPE) is one of the favored materials for total joint replacement, but its wear particles cause osteolysis. This study aims to elucidate the signaling that mediates the effects of UHMWPE particles on bone cells. Methods RAW264.7 and MC3T3-E1 cells were treated with UHMWPE particles. Chemerin/ChemR23 signaling was manipulated by either overexpressing Rarres2 and Cmklr1 or silencing Cmklr1. The osteoblast and osteoclast differentiation was evaluated by Alizarin red and TRAP staining, respectively. The expression of osteogenic and osteoclastogenic markers was assessed with quantitative real time PCR and western blot. Results UHMWPE particles upregulated the expression of Rarres2 and Cmklr1 in both osteoblast and osteoclast precursor cells. UHMWPE particles induced osteoclast differentiation while inhibited osteoblast differentiation, and this effect was abrogated by silencing Cmklr1 but augmented by the overexpression of Rarres2 and Cmklr1. Similarly, the expression of osteogenic marker genes was inhibited while that of osteoclastogenic marker genes was activated by UHMWPE particles, and this effect was abolished by silencing Cmklr1 and enhanced by Rarres2 and Cmklr1 overexpression. Conclusions These results demonstrated that chemerin/ChemR23 signaling plays a central role in the effects of UHMWPE particles on the balance of osteogenic and osteoclastogenic differentiation, which changes the course of bone remodeling and eventually results in osteolysis.

Background Osteoporosis and related complications have been increasing with the aging population. Osteoporotic vertebral compression fractures (OVCFs) are the most common among all osteoporotic fractures. The purpose of this study was performed to compare the efficiency and safety of vertebroplasty versus conservative treatment for acute OVCFs. Methods The conduct of this study followed the Declaration of Helsinki principles and the reporting of this study adhered to the Consolidated Standards of Reporting Trials guidelines for randomized controlled trials. Written informed consent was obtained from every participant. Participants were randomly assigned (1:1) to receive either vertebroplasty or control group. The primary outcome was pain relief at 1 month and 1 year, measured with a Visual Analogue Scale score. The secondary outcomes were Roland-Morris Disability Questionnaire, short form score, European Quality of Life-5 Dimensions, and postoperative complications. Results We hypothesize that vertebroplasty will provide a rapid decrease of pain and an early return to daily life activities compared with the control group. Trial registration This study protocol was registered in Research Registry (researchregistry5624).

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used in large joint replacement. Osteolysis induced by the UHMWPE wear particles is one of the main causes of replacement failure. This study aims to elucidate whether dendritic cells play a role in UHMWPE particle-induced osteolysis. An in vitro Raw 264.7 and DC 2.4 coculture system was employed to examine the effects of dendritic cells on the inflammatory and osteoclastogenic responses of Raw 264.7 toward UHMWPE particles. The expression of cytokines, NF-κB, and osteoclast marker genes was analyzed by ELISA, western blot, or quantitative PCR. The osteoclast differentiation was measured by TRAP staining and flow cytometry. UHMWPE particles induced Raw 264.7 cells to differentiate into osteoclasts, which was enhanced by coculturing with DC 2.4 cells. DC 2.4 cells augmented UHMWPE particle-elicited activation of NF-κB signaling, higher levels of TNF-α and MCP-1, and an increased expression of MMP-9, Calcr, and Ctsk, though DC 2.4 coculture alone did not significantly cause the aforementioned changes. These results suggest that dendritic cells, among other immune cells recruited by UHMWPE particle induced inflammation, could further exacerbate inflammation and osteolysis.