FIGURE 5.

FoxO transcriptional function is necessary to regulate cell size in starved cardiomyocytes. Cardiomyocytes were infected with β-galactosidase or dominant negative FoxO1 (Δ256) adenovirus for 24 h, and then cells were either replenished with fed or starved media for another 24 h. A and B, β-galactosidase (βgal)-infected cardiomyocytes subjected to starvation have a significant reduction in cell size (B) compared with fed (A) cardiomyocytes. C and D, dominant negative FoxO1 (Δ256)-infected cardiomyocytes subjected to starvation (D) fail to reduce cell size compared with fed cardiomyocytes (C). E, cardiomyocyte cell size (n = 200) was quantified for β-galactosidase and Δ256-infected cardiomyocytes in both fed and starved conditions for three independent experiments. Cardiomyocytes are immunostained with sarcomeric α-actinin (cardiac muscle actinin, green) and To-Pro3 (nucleus, blue). Representative cells for each condition were shown with white arrows. Significance (*) was determined by one-way analysis of variance (ANOVA) (p < 0.05; n = 3).