TMF inhibits extracellular matrix degradation by regulating the C/EBPß/ADAMTS5 signaling pathway in osteoarthritis.

Osteoarthritis (OA) is a chronic joint disease, characterized by degenerative destruction of articular cartilage. Chondrocytes, the unique cell type in cartilage, mediate the metabolism of extracellular matrix (ECM), which is mainly constituted by aggrecan and type II collagen. A disintegrin and metalloproteinase with thrombospondin 5 (ADAMTS5) is an aggrecanase responsible for the degradation of aggrecan in OA cartilage. CCAAT/enhancer binding protein ß (C/EBPß), a transcription factor in the C/EBP family, has been reported to mediate the expression of ADAMTS5. Our previous study showed that 5,7,3',4'-tetramethoxyflavone (TMF) could activate the Sirt1/FOXO3a signaling in OA chondrocytes. However, whether TMF protected against ECM degradation by down-regulating C/EBPß expression was unknown. In this study, we found that aggrecan expression was down-regulated, and ADAMTS5 expression was up-regulated. Knockdown of C/EBPß could up-regulate aggrecan expression and down-regulate ADAMTS5 expression in IL-1ß-treated C28/I2 cells. TMF could compromise the effects of C/EBPß on OA chondrocytes by activating the Sirt1/FOXO3a signaling. Conclusively, TMF exhibited protective activity against ECM degradation by mediating the Sirt1/FOXO3a/C/EBPß pathway in OA chondrocytes.

Geniposide ameliorated dexamethasone-induced endoplasmic reticulum stress and mitochondrial apoptosis in osteoblasts.

ETHNOPHARMACOLOGICAL RELEVANCE: Eucommia ulmoides Oliver has been traditionally used for treatment of various diseases, including osteoporosis, knee pain, and paralysis. The extract of Eucommia ulmoides has been reported to stimulate the bone formation and suppress the bone resorption, leading to protection against osteoporosis (OP). Geniposide (GEN) has been considered as one of the effective compounds responsible for the therapeutic efficacy of Eucommia ulmoides against OP. AIM OF THE STUDY: To explore whether GEN protected against dexamethasone (DEX)-induced osteoporosis (OP) by activating NRF2 expression and inhibiting endoplasmic reticulum (ER) stress. MATERIALS AND METHODS: The DEX-induced rat OP models were duplicated. The pathological changes were examined by histological/immunohistochemical evaluation and micro-computed tomography (micro-CT) assessment. Apoptosis was detected by a flow cytometer. Mitochondrial Ca2+ concentrations and mitochondrial membrane potential were detected. Western blot assays were used to detect the protein expression. RESULTS: GEN effectively reversed DEX-induced pathological changes of trabecular bone in rats. In addition, the DEX-increased expression of ATF4/CHOP was also ameliorated. In MC3T3-E1 cells, DEX promoted endoplasmic reticulum (ER) stress and mitochondrial apoptosis. Inhibition of ER stress abolished the induction of apoptosis by DEX. Similarly, GEN significantly ameliorated DEX-induced mitochondrial apoptosis. The possible underlying mechanism might be associated with the pharmacological effects of GEN on activating the expression of NRF2 and alleviating ER stress in DEX-treated MC3T3-E1 cells. CONCLUSION: GEN ameliorated DEX-induced ER stress and mitochondrial apoptosis in osteoblasts.

Characterization of pruned tea branch biochar and the mechanisms underlying its adsorption for cadmium in aqueous solution.

In the present study, discarded pruned tea branch was used to prepare a new biochar, and the physicochemical properties and adsorption characteristics were investigated by characterization and batch experiments. With increasing pyrolysis temperature from 400 to 800 °C, the yield, specific surface area, and acidic functional groups had significant differences. The optimum adsorption conditions were determined as pH = 6 and dosage of 2 g L-1. The pseudo-second-order kinetic and Langmuir isothermal model could fit well to the adsorption data, which showed that the adsorption process was dominated by monolayer chemical adsorption. The highest adsorption property (74.04 mg g-1) was obtained by the pyrolysis of tea branch biochar (TBB) at 700 °C owing to the adsorption mechanisms, including surface complexation, precipitation, metal ion exchange, and Cd2+-π interaction. After five cycles of desorption, biochar still showed superior adsorption (80%). Hence, the TBB acted as a regenerable adsorbent for treating Cd2+-containing wastewater.