LR12 Promotes Liver Repair by Improving the Resolution of Inflammation and Liver Regeneration in Mice with Thioacetamide- (TAA-) Induced Acute Liver Failure

[Oridonin suppresses the effect of thioacetamide for promoting osteoclast differentiation of RAW264.7 cells and inhibiting osteoblast differentiation of bone mesenchymal stem cells]

OBJECTIVE

To explore the effect of oridonin (ORI) for suppressing thioacetamide (TAA)-induced osteoclast differentiation of RAW264.7 cells and antagonizing the inhibitory effect of TAA on osteogenic differentiation of bone mesenchymal stem cells (BMSCs).

METHODS

The effects of TAA and ORI on the proliferation of RAW264.7 cells and SD rat BMSCs were examined using CCK-8 assay. TRAP staining and immunofluorescence staining were used to observe the effects of TAA and ORI on osteoclast differentiation in RAW264.7 cells. The expressions of osteoclast-specific proteins in the treated cells were detected using Western blotting, and p65 nuclear translocation and reactive oxygen species (ROS) production in the cells were assessed with immunofluorescence assay and flow cytometry. Alkaline phosphatase (ALP) staining and alizarin red staining were used to examine the effects of TAA and ORI on osteogenic differentiation of BMSCs, and the expressions of osteogenic and apoptosis-related proteins in the cells were detected with Western blotting.

RESULTS

Compared with RAW264.7 cells treated with TAA alone, the cells with the combined treatment with TAA and ORI showed decreased osteoclast differentiation (P < 0.01) and significant inhibition of the MAPK/NF-κB pathway (P < 0.01) with reduced p65 nuclear translocation and intracellular ROS production (P < 0.01). In rat BMSCs, treatment with TAA alone significantly inhibited ALP activity and formation of calcified nodules (P < 0.01) and induced obvious cell apoptosis. Compared with TAA-treated BMSCs, the cells treated with both TAA and ORI showed upregulated expressions of the BMP-2/RUNX2 pathway with enhanced ALP activity (P < 0.01) and calcium deposition (P < 0.01) and a lowered cell apoptosis level.

CONCLUSION

ORI inhibits TAA-induced osteoclast differentiation via regulating the MAPK/NF-κB pathway and antagonizes TAA-induced inhibition of bone formation by regulating the BMP-2/RUNX2 pathway.

Oridonin Attenuates Thioacetamide-Induced Osteoclastogenesis Through MAPK/NF-κB Pathway and Thioacetamide-Inhibited Osteoblastogenesis Through BMP-2/RUNX2 Pathway

Osteoporosis, an age-related metabolic bone disease, is mainly caused by an imbalance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. At present, there are many osteoporosis drugs that can promote bone formation or inhibit bone resorption. However, there were few therapeutic drugs that can simultaneously promote bone formation and inhibit bone resorption. Oridonin (ORI), a tetracyclic diterpenoid compound isolated from Rabdosia rubescens, has been proved to have anti-inflammatory, anti-tumor effects. However, little is known about the osteoprotective effect of oridonin. Thioacetamide (TAA) is a common organic compound with significant hepatotoxicity. Recent studies have found that there was a certain association between TAA and bone injury. In this work, we investigated the effect and mechanism of ORI on TAA-induced osteoclastogenesis and inhibition of osteoblast differentiation. The results showed that TAA could promote the osteoclastogenesis of RAW264.7 by promoting the MAPK/NF-κB pathway, and also promoted p65 nuclear translocation and activated intracellular ROS generation, and ORI can inhibit these effects to inhibit TAA-induced osteoclastogenesis. Moreover, ORI can also promote the osteogenic differentiation pathway and inhibit adipogenic differentiation of BMSCs to promote bone formation. In conclusion, our results revealed that ORI, as a potential therapeutic drug for osteoporosis, could protect against TAA-induced bone loss and TAA-inhibited bone formation.

Nangibotide attenuates osteoarthritis by inhibiting osteoblast apoptosis and TGF-β activity in subchondral bone

Osteoarthritis (OA) is a chronic joint disorder that causes cartilage degradation and subchondral bone abnormalities. Nangibotide, also known as LR12, is a dodecapeptide with considerable anti-inflammatory properties, but its significance in OA is uncertain. The aim of the study was to determine whether nangibotide could attenuate the progression of OA, and elucidate the underlying mechanism. In vitro experiments showed that nangibotide strongly inhibited TNF-α-induced osteogenic reduction, significantly enhanced osteoblast proliferation and prevented apoptosis in MC3T3-E1 cells. Male C57BL/6 J mice aged 2 months were randomly allocated to three groups: sham, ACLT, and ACLT with nangibotide therapy. Nangibotide suppressed ACLT-induced cartilage degradation and MMP-13 expression. MicroCT analysis revealed that nangibotide attenuated in vivo subchondral bone loss induced by ACLT. Histomorphometry results showed that nangibotide attenuated ACLT-induced osteoblast inhibition; TUNEL assays and immunohistochemical staining of cleaved-caspase3 further confirmed the in vivo anti-apoptotic effect of nangibotide on osteoblasts. Furthermore, we found that nangibotide exerted protective effects by suppressing TGF-β signaling mediated by Smad2/3 to restore coupled bone remodeling in the subchondral bone. In conclusion, the findings suggest that nangibotide might exert a protective effect on the bone-cartilage unit and maybe an alternative treatment option for OA.