Fig 1.
CypD is more important for calcium overload induced mitochondrial permeability transition in the liver compared with skeletal muscle.
Representative calcium retention capacity assay of a single experiment on isolated mitochondria from skeletal muscle (A) and liver (B) of WT and CypD KO mice fed HFD for 10 weeks. (C) The average number of calcium additions required before irreversible mPTP opening was observed as indicated by fluorescence plateau and quantified for skeletal muscle and liver mitochondria. For gastrocnemius WT = 9, KO = 5; for liver WT = 7 and KO = 4. *p < 0.05.
Fig 2.
Deletion of CypD does not alter other mPTP protein abundance.
(A) Western blot for CypD protein in liver, plantaris muscle, heart and epididymal fat tissue. MKO mice have muscle-specific deletion of CypD in skeletal muscle and heart (A), while LKO mice have liver-specific deletion (B). Littermate floxed mice are used as WT showing normal CypD expression. Representative western blot and quantification, respectively, in skeletal muscle (C and E) and liver (D and F) for VDAC, ATP Synthase and ANT. Quantification is normalized to the loading control, β-actin. *p < 0.05; n = 4–6.
Fig 3.
CypD deletion in skeletal muscle does not affect whole body glucose homeostasis.
(A) Body weight at basal levels and following 11 wk of HFD; (B) Epididymal fat; (C) liver and (D) plantaris muscle tissue weight normalized to tibia length in HFD fed mice; (E) Blood glucose following i.p. injection of glucose in normal chow fed mice and (F) area under the glucose curve; (G) Blood glucose following i.p. injection of glucose in HFD fed mice and (H) area under the glucose curve; (I) Representative western blot and (J) quantification of phosphorylated (S473) and total Akt in plantaris muscle of HFD fed WT and MKO mice before and 10 min after i.p. injection of insulin. ***p < 0.001 basal vs. HFD; *p < 0.05 basal vs. insulin; n = 10–12.
Fig 4.
CypD is important for metabolic control in the liver under high-fat diet conditions.
(A) Body weight at basal levels and following 11 wk of HFD; (B) Epididymal fat, (C) liver and (D) plantaris muscle tissue weight normalized to tibia length in HFD fed mice; (E) Blood glucose following i.p. injection of glucose and (F) area under the glucose curve under normal chow conditions; (G) Blood glucose following i.p. injection of glucose and (H) area under the glucose curve following 11 wk of HFD; (I) Blood glucose following i.p. injection of pyruvate and (J) area under the curve following 14 wk of HFD; (K) Representative Oil red O staining of liver sections from WT and LKO mice following 14 wk of HFD and (L) average lipid droplet size. ***p < 0.001 basal vs. HFD, * and **p < 0.05 WT vs. LKO; GTT and PTT n = 9–11; Oil Red O quantification n = 4.