Fig. 6

Effect of HFD on cartilage gene expression in male and female mice. A 2-way hierarchical clustering analysis of cartilage gene expression values versus experimental groups. Heatmap color legend signifies standardized expression values calculated by subtracting the mean and dividing by the standard deviation. Two-factor ANOVA chart indicates significant factor effects for genes in corresponding rows. B Sex-specific effects of HFD on gene expression evaluated by log2 transformed volcano plot comparisons. Labelled genes have p < 0.05 and minimum log 2-transformed differential expression value ±0.378 (1.3-fold change). Note the analysis does not include a false discovery rate correction and should be considered exploratory. C Expression data for selected genes presented as log 2-transformed fold-change normalized to male Chow diet samples using the delta-delta Ct method. Boxplots represent the 25th to 75th percentiles, horizontal line indicates the median, and whiskers demonstrate maximum and minimum values. Fisher’s LSD post-hoc paired comparisons shown for p < 0.10. Two-way ANOVA values: Col2a1 (Sex [p = 0.091], Diet [p = 0.013], Interaction [p = 0.032]); Col11a1 (Sex [p = 0.89], Diet [p = 0.12], Interaction [p = 0.038]); Comp (Sex [p = 0.049], Diet [p = 0.17], Interaction [p = 0.079]); Cfb (Sex [p = 0.047], Diet [p = 0.0003], Interaction [p = 0.76]); Adamts5 (Sex [p = 0.88], Diet [p = 0.15], Interaction [p = 0.10]); Mmp13 (Sex [p = 0.083], Diet [p = 0.083], Interaction [p = 0.11]); Ddit3 (Sex [p = 0.041], Diet [p = 0.010], Interaction [p = 0.079]); Xbp1 (Sex [p = 0.38], Diet [p = 0.084], Interaction [p = 0.11]); ClpP (Sex [p = 0.082], Diet [p = 0.24], Interaction [p = 0.043]); Prkaa1 (Sex [p = 0.0005], Diet [p = 0.92], Interaction [p = 0.14]); Sirt3 (Sex [p = 0.0002], Diet [p = 0.17], Interaction [p = 0.81]); Acly (Sex [p < 0.0001], Diet [p = 0.96], Interaction [p = 0.60]). Sample sizes for each analysis provided in Supplemental Table S3