Fig. 7. Validation of predictions for the ISMARA-inferred³⁹ activity of transcription factors (TFs) during muscle aging.

a Representative western blot analysis of the abundance of TFs ERRα, YY1, and PPARα in the gastrocnemius muscle (tissue lysate) of 8 and 28-months-old mice, respectively. b Quantification of western blots showing the relative abundance of TFs ERRα, YY1, and PPARα normalized to the nuclear protein histone H3, respectively. *Denotes a significant difference based on two-sided Mann–Whitney U test between 8 and 28 months-old mice with p-value < 0.05. c Representative images of tibialis anterior cross sections of 8 and 28-months-old mice with magnification stained for ERRα (red), Laminin α2 (white), and DAPI (blue). d Quantification of the percentage of ERRα-positive nuclei in tibialis anterior fibers of 8 and 28-months-old mice, respectively. ***Denotes a significant difference based on two-sided Student’s t-test between 8 and 28-months-old mice with p-value < 0.001. All values were visualized as mean ± standard error of the mean (SE).