Curcumin inhibits lipopolysaccharide-induced differentiation of RAW264.7 cell-derived osteoclasts through regulation of p53/SLC7A11/GPX4 pathway
AIM:The study aimed to explore the effect of curcumin(Cur)on lipopolysaccharide(LPS)-in-duced RAW264.7 cell-derived osteoclasts,together with its underlying mechanism.METHODS:An osteoclast model was established by treating RAW264.7 cells with LPS.The viability of the cells was assessed by CCK-8 assays and osteo-clast formation was evaluated by tartrate-resistant acid phosphatase(TRAP)activity.The levels of reactive oxygen species(ROS),Fe2+,glutathione(GSH),and malondialdehyde(MDA)were examined by biochemical assays.Mitochondrial morphology was assessed by transmission electron microscopy.The mRNA and protein levels of p53,glutathione peroxi-dase 4(GPX4),and solute carrier family 7 member 11(SLC7A11)were determined by RT-qPCR and Western blot,re-spectively.RESULTS:Treatment with LPS successfully induced osteoclasts formation in RAW264.7 cells.The TRAP results showed that compared with the LPS-treated group,the number of osteoclasts and TRAP activity in the curcumin-treated group decreased dose-dependently(P<0.01).Compared with the control group,the LPS+Erastin group showed significantly increased TRAP activity(P<0.01),while after curcumin treatment,the TRAP activity declined in a dose-de-pendent manner(P<0.01).The results of the biochemical tests showed that compared with the control group,the LPS+Erastin group had significantly elevated levels of ROS,Fe2+,and MDA,while the GSH level was significantly reduced(P<0.01),and compared with the LPS+Erastin group,the ROS,Fe2+,and MDA levels in the curcumin group decreased(P<0.01)and GSH levels increased(P<0.01).These effects were all dose-dependent.Transmission electron microscopy showed that compared with the LPS group,the LPS+Erastin group had reduced mitochondrial cristae and increased mem-brane density,while after treatment with curcumin,both these effects were reversed.The RT-qPCR and Western blot re-sults showed that compared with the control group,the mRNA and protein levels of p53 in the LPS+Erastin group were sig-nificantly increased,while those of of SLC7A11 and GPX4 were significantly reduced(P<0.01).After curcumin treat-ment,the p53 mRNA and protein levels were reduced while the levels of SLC7A11 and GPX4 were increased(P<0.01).CONCLUSION:Curcumin can inhibit lipopolysaccharide-induced differentiation of RAW264.7 cells into osteoclasts,and its mechanism may be related to the inhibition of the p53/SLC7A11/GPX4 signaling pathway.