Knockdown of low density lipoprotein receptor-related protein 1 in chondrocytes

Yang Er-ping; Peng Fei; Liang Jie; Du Yuan-li

doi:10.3969/j.issn.2095-4344.2016.15.006

Abstract：BACKGROUND:Tumor necrosis factor α, as a pathogenic factor, induces the inflammatory reaction mainlyvia the activation of the nuclear factor kappa B signaling pathway. Low density lipoprotein receptor-related protein 1 (LRP1) is involved in the regulation of the inflammatory reaction induced by cytokines. <br> OBJECTIVE:To study the effect of knockdown of LRP1 on tumor necrosis factor α-induced inflammatory reaction. <br> METHODS: Primary cultured rat chondrocytes were transfected with lentivirus-mediated RNA interference to knockdown LRP1 gene. Three days after lentivirus transfection, chondrocytes were pretreated with Bay 11-7082 (10 μmol/L) for 30 minutes prior to the addition of tumor necrosis factor α (30 μg/L) for 30 minutes. Signaling protein and mRNA expressions in chondrocytes were detected by western blot assay and real-time PCR analysis, respectively. Chondrocytes were pretreated with or not Bay 11-7082 (10 μmol/L) 30 minutes prior to the addition of tumor necrosis factor α (30 μg/L) for 12 hours after starvation in DMEM for overnight, and the culture medium was colected for ELISA determination of matrix metaloproteinase 13 level. <br> RESULTS AND CONCLUSION:Tumor necrosis factor α receptor 1 expression was upregulated in chondrocytes after lentivirus-induced knockdown of LRP1. Increased expression of inducible nitric oxide synthase and activation of the nuclear factor kappa B signaling pathway were found after the addition of tumor necrosis factor α in shLRP1 group. Moreover, increased level of matrix metaloproteinase 13 was determined by ELISA. Taken together, knockdown of LRP1 up-regulates the expression of tumor necrosis factor α-induced inducible nitric oxide synthase and matrix metaloproteinase 13 through the activation of the nuclear factor kappa B signaling pathway.