Figure 2. Wnt7a ectopic expression reduces IL-1β induced upregulation of OA-related genes and NF-κB activity in vitro.

(a) Representative images of Wnt7a IF analysis of normal human articular chondrocytes (nHACs) after infection with lenti-GFP or lenti-Wnt7a-GFP. Wnt7a immunofluorescence images were overlaid with GFP expression. Percentage of cells positive for lenti-GFP or lenti-Wnt7a-GFP was quantified based on GFP production, which were 81.4% and 78.8%, respectively. (b) RT-PCR analysis of nHACs gene expression after infection with lenti-GFP or lenti-Wnt7a-GFP with or without IL-1β (5 ng/mL). Lenti-Wnt7a-GFP viral infection significantly reduced IL-1β upregulation of Collagen X, IL-1β, iNOS, and several MMPs. A student’s t-test was used for evaluating the statistical significance between the gene expression of lenti-GFP and lenti-Wnt7a cells under either control or IL-1β conditions. (c) NF-κB luciferase assay of NF-κB activity after infection with lenti-GFP or lenti-Wnt7a-GFP and treatment with or without IL-1β (5 ng/mL). Relative luciferase activity in reference to Renilla luciferase internal control is shown. Experiments were conducted with biological triplicates and repeated at least three times. Analysis of variance (ANOVA) with post-hoc tests was used for evaluating the statistical significance of the GFP vs. Wnt7a and control vs. IL-1β luciferase activity. All data are shown as mean ± SEM. *p < 0.05.