Extended Data Fig. 4: APP impairs adipocyte mitochondrial function owing to defective mitochondrial protein import (related to Fig. 5a,b,f).
a, In vitro mitochondrial respiration (OCR) in sWAT SVF differentiated adipocytes from control (APP–) and APP transgenic (APP+) mice. Cells are pre-incubated for 5 μg ml–1 Dox for 48 h to induce APP overexpression. n = 5 per group. b, Relative in vitro ATP production changes from SVF-differentiated adipocytes of APP transgenic mice compared with control mice. Different dosages of Dox were applied to cells. n = 8 per dosage. c, Combined light and fluorescence microscopy images displaying mitochondrial membrane potential (MMP) through TMRE staining (Red) from SVF-differentiated adipocytes of control and APP transgenic mice. DMSO serves as the negative control, and FCCP is a positive control to collapse MMP. Images were chosen from three independent experiments and are representative of at least 12 fields for each group. Scale bars, 50 μm. d–g, Quantification for indirect calorimetry measurements in control and APP transgenic mice in light and dark cycles: oxygen consumption (VO2) (d); CO2 production (VCO2) (e); RER (f) and calculated energy expenditure (g). n = 6 mice per group. h, Western blotting for Aβ-40/42 in mitochondrial and cytoplasmic fractions from sWAT in control and APP-overexpressing mice. Aβ 1-42 protein has been loaded separately as a positive control. n = 2 mice per group. Representative image is chosen from three independent experiments. i, Western blotting for mitochondrial complex components using oxidative phosphorylation antibody cocktail in mitochondrial and cytoplasmic fractions from sWAT in control and APP-overexpressing mice. n = 2 mice per group. A representative image was chosen from three independent experiments. j, Gene expressions for mitochondrial complex components measured in i. n = 5 (APP–) or 6 (APP+) mice per group. k, Western blotting for COX5A in sWAT in control and APP-overexpressing mice. n = 3 mice per group. A representative image was chosen from three independent experiments. Data are shown as mean ± s.e.m. of biologically independent samples. Two-way ANOVA (a); one-way ANOVA followed by a Tukey post-test (b); Two-tailed Student’s t-test (d–g,j).
