Figure 1.

PEMTKO mice fed HFD lack UCP1 protein concomitant with decreased CL. (A) Body mass in the WT or PEMTKO mice fed HFD for 10 weeks, n = 8. (B) Fat mass, n = 8. (C) Cold-tolerance test in the PEMTKO mice. The mice were single-housed and placed in a temperature-controlled room at 4 °C for 6 h, n = 3–5. (D) mRNA levels of PEMT in BAT, n = 7–8. (E) Images of BAT sections stained with hematoxylin and eosin. (F) Protein levels of UCP1 and citrate synthase (CS). (G) mRNA levels of UCP1, n = 4. (H) UCP1-dependent respiration in mitochondria isolated from BAT. Respiration was stimulated with 0.2 mM malate and 5 mM pyruvate. UCP1 was inhibited using 4 mM GDP, n = 6. (I) Protein levels of ETS complexes in whole tissue lysates. (J) ATP production in isolated BAT mitochondria. ATP production was measured in the presence of 0.2 mM malate, 5 mM glutamate, 5 mM pyruvate, and 5 mM succinate at increasing concentrations of ADP, n = 3–4. (K) O₂ consumption using the same conditions described for ATP production, n = 3–4. (L) ATP/O ratio calculated from the ATP produced per oxygen consumed, n = 3–4. (M) EM images of BAT mitochondria. (N) Detection of phospholipids extracted from the BAT mitochondria by TLC. (O) Analysis of CL species via LC-MS, n = 9. (P) Analysis of PC species via LC-MS, n = 4–5. Data are expressed as mean ± SEM, *p < 0.05.