Mitochondrial turnover is sustained in FoxO1 KO induced browning of fat tissue.

(A,B) Glucose tolerance test and calculation of area under the curve (AUC) for control (Ctrl) and adO1KO mice; n=6–8. (C) Measurement of homeostasis model index of insulin resistance (HOMA-IR); n=8–12. (D–E) Analyses of UCP1 proteins in inguinal adipose tissues by immunohistochemistry (panel D, magnification, 200×) and Western blotting followed by densitometric analyses (E, n=6). (F) Measurement of body temperatures; n=6–8. (G) Transmission electron microscopic view of inguinal adipose tissue sections. The arrows point to mitochondria engulfed by autophagosome for clearance, and the asterisks mark the mitochondria not engulfed by autophagosome. (H) Counts of mitochondria inside autophagosome (MiA, marked by arrows) and mitochondria outside autophagosome (MoA, marked by asterisks) under the transmission electron microscope (area of 35 μm2); n=6–8. (I,J) Western blotting (I) and densitometric (J) analyses of FoxO1 and autophagy proteins; n=6. (K) Schematic view of how autophagic activity was sustained in adO1KO mice; *P<0.05, **P<0.01, ***P<0.001; n.s., not significant.