Figure 3Plasma (A) BCAA levels in wt and LowOXPHOS mice (wt, n= 4; LowOXPHOS, n= 4). Bars are the mean ± s.e.m. of n= 3 experiments, 6 replicas/condition. Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. Scheme of the BCAA catabolism pathway (B, left panel) and 14C(u)-leucine and 14C(u)-isoleucine uptake (B, right panels) in myocytes expressing or not ATPIF1H49K. Skm (C) BCAA levels in wt and LowOXPHOS mice (wt, n= 4; LowOXPHOS, n= 4). Bars are the mean ± s.e.m. of n= 3 experiments, 6 replicas/condition. Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. D, E). oxidation (D) and incorporation into lipids (E) in myocytes expressing or not ATPIF1H49K. Bars are the mean ± s.e.m. of n= 3 experiments, 6 replicas/condition. Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. F. Longitudinal (left panels) and transversal (right panels) slices of soleus stained with hematoxylin/eosin. im-WAT infiltrations and fiber shrinkage (arrows) in HFD-fed LowOXPHOS mice (wt + HFD, n= 4; LowOXPHOS + HFD, n= 4; 10 fields/mouse). (G-I). Motor function tests. Rotarod (G; wt, n= 7; LowOXPHOS, n= 6), Open Field (H; wt, n= 4; LowOXPHOS, n= 4) and gripforce (after fatigue, I; wt, n= 7; LowOXPHOS, n= 6) tests. In H, lines represent the movement of the mice in the cage. The histogram represents the relative time that wt and and LowOXPHOS mice expended in the corners. Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. (J, K) Quantitative Skm lipidomics at day 80 of HFD (J). The color scale (brown to blue) in the heat-map represents LowOXPHOS/wt amounts of detailed lipid species. A p-value ≤ 0.05 was considered statistically significant (red). In the lower heat-map (K), the color scale (yellow to blue) highlights an increase in DAG in HFD-fed LowOXPHOS mice. Each sample is a pool from 4 mouse extracts. Histograms show the total amounts of Skm DAG (wt, n= 8; LowOXPHOS, n= 8). L. Blood triglycerides on the 80th day of HFD (wt + HFD, n= 10; LowOXPHOS + HFD, n= 10). Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. M. Skm relative expression of the GLUT1, GLUT3, PPARβ/δ and PGC1α by qPCR (wt, n= 5; LowOXPHOS, n= 5). Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. N. qPCR relative expression of myokines (wt, n= 5; LowOXPHOS, n= 5). Red or blue color represents higher or lower % expression, respectively, compared to that in wt. SPARC, osteonectin; OSTN, musclin; LIF, interleukin 6 family cytokine; FKN, fractalkine; FSTL1, follistatin-like protein 1; FNDC5, irisin; ADIPOQ, adiponectin. Data information: Bars are the mean ± s.e.m. of the indicated (n) mice/genotype *p <0.05 when compared to wt by ANOVA or Student's t-test. O. Blood glucose following the administration of HFD (wt + HFD, n= 10; LowOXPHOS + HFD, n= 10). T2D onset occurred on day 80 in wt and day 60 in LowOXPHOS mice. P. Insulin (ITT) and glucose (GTT) tolerance tests on day 60 of HFD (wt + HFD, n= 10; LowOXPHOS + HFD, n= 10). LowOXPHOS but not wt mice appeared diabetic.