| Objective: To investigate the effect of liver X receptors(LXRs)on p65 NF-κB in LPS-induced macrophages of RAW264.7 mice and to explore its possible mechanism.Methods:Firstly,RAW264.7 cells were used as the research objects in this study.LPS-induced RAW264.7 cells were served as the model of inflammation for observing the effect of LXRs-pretreated macrophages on the expression and polyubiquitination of p65 NF-κB.The protein synthesis inhibitor iminocyclohexanone(CHX)were used to block the synthesis of p65 NF-κB and to analyze whether LXRs affect the stability of p65 NF-κB.Then,The expression of SOCS1 gene and protein were observerd by Western blot and PCR.After that,cells were transfected by siRNA interference technology,and silenced SOCS1 expression in RAW264.7 cells to observe the impact on the expression of SOCS1 and p65 NF-κB in LPS-induced macrophages and the polyubiquitin of p65 NF-κB by LXRs.Results: The pretreatment with LXRs significantly inhibited the expression of p65 NF-κB protein in LPS-induced RAW264.7 cells and also significantly up-regulated the expression of mRNA and protein of E3 ligase SOCS1.T0901317 promoted ubiquitination and degradation of p65 NF-κB when proteasome inhibitor MG132 blocked the ubiquitination pathway.The transfection of SOCS1 siRNA into RAW264.7 cells could block the expression of SOCS1 and significantly inhibit the ubiquitination and ubiquitination degradation of p65 NF-κB induced by T0901317.Conclusions: LXRs pretreatment can significantly inhibit the expression of p65 NF-κB protein in LPS-induced RAW264.7 cells,which may result from the SOCS1-mediated ubiquitination pathway by LXRs down-regulating p65 NF-κB levels. |
