KLF2 Protects against Osteoarthritis by Repressing Oxidative Response through Activation of Nrf2/ARE Signaling In Vitro and In Vivo

Figure 3

KLF2 overexpression inhibits IL-1β-induced apoptosis and chondrocyte degradation through the suppression of ROS production in vitro. SW1353 cells were infected with nonspecific control virus (Lv-NC) or KLF2-expressing virus (Lv-KLF2) or incubated with the pharmacological KLF2 activator simvastatin (Sim). After 24 h, cells were treated with or without GGPP (GP, an inhibitor of KLF2) for 8 h prior to 24 h treatment with 20 ng/ml IL-1β. (a) Real-time PCR was performed to assess KLF2 mRNA expression levels. (b) Western blotting analysis was performed to assess KLF2 expression at the protein level. β-Actin was used as an endogenous control. Quantitative analysis of KLF2 protein levels based on the specific signal intensities measured using ImageJ. (c) Cell viability was determined by CCK-8 assay. (d) Apoptosis was determined by Annexin V/PI staining followed by flow cytometry assays. (e) Expression of MMP3, MMP9, MMP13, and COL2A1 was investigated by Western blotting analysis. β-Actin was used as an endogenous control. (f) Quantitative analysis of MMP3, MMP9, MMP13, and COL2A1 protein levels based on specific signal intensities measured using ImageJ. SW1353 cells were infected with Lv-NC or Lv-KLF2 or incubated with the pharmacological activator of KLF2 simvastatin. After 24 h, cells were treated with or without GP for 8 h prior to 30 min treatment with 10 ng/ml IL-1β. (g) ROS generation was determined by DCF-DA staining followed by flow cytometry analysis. All data are expressed as the . and .

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