Effects of microRNA-146a on the proliferation and apoptosis of human osteoarthritis chondrocytes by targeting TRAF6 through the NF-κB signalling pathway.

The present study aims to investigate the effects of miR-146a on the proliferation and apoptosis of human osteoarthritis (OA) chondrocytes by targeting tumour necrosis factor receptor-associated factor 6 (TRAF6) through nuclear factor-κB (NF-κB) signalling pathway. Human normal and OA chondrocytes were selected and divided into the normal group, blank group, negative control (NC) group, miR-146a mimics group, miR-146a inhibitors, miR-146a inhibitor + si-TRAF6 group and si-TRAF6 group. Quantitative real-time PCR (qRT-PCR) was applied to detect the expressions of miR-146a, TRAF6 mRNA and NF-κB mRNA. Western blotting was used to detect the protein expressions of TRAF6 and NF-κB. CCK-8 assay and flow cytometry were used to detect cell proliferation and apoptosis. Compared with normal chondrocytes, the expression of miR-146a decreased, while the mRNA and protein expressions of TRAF6 and NF-κB increased in OA chondrocytes. OA chondrocytes had a lower proliferation rate and a higher apoptosis rate than the normal chondrocytes. Compared with the blank, NC and si-TRAF6 groups, the expression of miR-146a increased in the miR-146a mimics group, but decreased in the miR-146a inhibitors and miR-146a inhibitor + si-TRAF6 groups. Compared with the blank, NC and miR-146a inhibitor + si-TRAF6 groups, the mRNA and protein expressions of TRAF6 and NF-κB decreased, cell proliferation rate increased and cell apoptosis rate decreased in the miR-146a mimics and si-TRAF6 groups, while opposite trends were observed in the miR-146a inhibitors group. Our study suggests that miR-146a could promote proliferation and inhibit apoptosis of OA chondrocytes by inhibiting TRAF6 expression and suppressing the activation of NF-κB signalling pathway.

[Protective effects of nourishing spleen yin recipe on endoplasmic reticulum stress-induced neuronal cell damage and its mechanism].

OBJECTIVE: To determine the protective effects of nourishing spleen yin recipe (Zibu Piyin Recipe, ZBPYR), a compound traditional Chinese herbal medicine, on endoplasmic reticulum (ER) in neuronal cells responding to the stress by using sero-pharmacological method. METHODS: The mouse neuroblastoma cell line Neuro2a cells were treated with tunicamycin (Tm, an inhibitor of N-glycosylation). The ZBPYR-treated cell group was established by incubating cells with ZBPYR serum for one hour and treated with Tm. Reverse transcriptase PCR (RT-PCR) was utilized to detect the mRNA expressions from two genes after treatments, ER molecular chaperone glucose regulated protein 78 (GRP78) and transcriptional factor CCAAT/ enhancer-binding protein-homologous protein (CHOP). Lactate dehydrogenase (LDH) assay was also carried out to determine the LDH leakage from Neuro2a cells after treated with Tm and staurosporine (STS). RESULTS: The ZBPYR-treated cell group at all tested ZBPYR dosages showed significantly reduced expressions of both genes compared with Tm (5 microg/ml) treated control group (P<0.05). Therefore, ZBPYR serum inhibited the expressions of GRP78 and CHOP in mRNA level under ER stress induced by Tm. Different concentrations of ZBPYR serum pretreatment reduced the LDH leakage compared with the Tm and STS groups (P<0.05). Therefore, ZBPYR serum may inhibit the LDH leakage induced by Tm and STS. CONCLUSION: ZBPYR has neuroprotective effects. The mechanisms may be associated with inhibition of ER stress and mitochondrial dysfunction.