Fig. 5

Spermidine promotes mitochondrial respiration and prevents mitochondrial dysfunction. A Oxygen consumption measurements of THP-1 macrophages by high-resolution respirometer. Digitonin was used for permeabilization. Malate (5 mM), ADP (2 mM) and glutamate (5 mM) to measure complex I-driven phosphorylating respiration (CI OXPHOS); succinate (5 mM) to measure CI + II OXPHOS; rotenone (1 mM) to inhibit complex I-driven respiration and measure CII OXPHOS; oligomycin (1.25 μM) to measure residual respiration (proton leak); CCCP (0.5 μM) to measure complex II-driven maximal uncoupled respiration (CII electron transfer capacity, CII ET). B ROS immunostaining (red) and Hoechst (blue) staining. Scale bar, 100 μm. Fluorescence intensity was calculated using Image J software. C JC-1 staining. The ratio of aggregate-to-monomer (red/green) fluorescence intensity represents mitochondrial membrane potential and was quantified using Image J software. Scale bar, 100 μm. D Mitochondrial membrane potential probed by O2k respirometer. E Western blot analysis of NDUFV2 and ATP5A1. Experiments were performed in triplicate. Data are expressed as mean ± SEM. One-way ANOVA followed by post hoc Sidak test. *P < 0.05, **P < 0.01, ***P < 0.001