Figure 6. Increased YAP nuclearization in aged MuSCs. (A) Micrographs of young and aged MuSCs stained for YAP (red), F-actin filaments (yellow), and nuclei (blue) after 30 min of static culture or PFSS treatment. (B) Total YAP fluorescent intensity was higher in aged MuSCs. PFSS did not affect YAP fluorescent intensity in MuSCs. (C) YAP nuclear-to-cytoplasmic fluorescent intensity ratio revealed 59% higher YAP nuclear localization in aged MuSCs, and no effect of PFSS. (D, E) Negative correlation between YAP nuclear-to-cytoplasmic ratio and cell attachment area in young and aged MuSCs after static culture or PFSS treatment. Young MuSCs, n = 50–61 cells (from 3 young mice). Aged MuSCs, n = 55–56 cells (from 3 aged mice). (F, G) Gene expression Yap and its downstream targets Ctgf and Cyr61 were decreased in aged MuSCs in comparison to young MuSCs. (H–K) Gene expression of Tead1 and Tead3 was decreased, Tead2 was unchanged, and Tead4 was increased in aged MuSCs. Young MuSCs, n = 11 (from 4 young mice). Aged MuSCs, n = 9 (from 3 aged mice). Abbreviations: MuSCs: muscle stem cells; PFSS: pulsating fluid shear stress. Fluores. intensity, fluorescence intensity. Values are mean ± SEM. *Significant effect of age, p < 0.05. Scale bar; 10 μm.