PPARα restores mitochondrial respiration <i>in vitro</i>.

(A-C) Seahorse extracellular flux analysis of R28 cells revealed that (B) maximal respiration and (C) respiratory reserve capacity were decreased by 4 hours exposure to 15 μM 4-Hydroxynonenyl (4-HNE), and restored by a 2-hour pretreatment with 25 μM fenofibric acid (Feno-FA) prior to 4-HNE exposure (n = 5 /group). (D-F) Seahorse extracellular flux analysis of adenovirus-infected R28 cells revealed that (E) maximal respiration was non-significantly decreased by 4 hours exposure to 15 μM 4-HNE in cells infected with β-Galactosidase-expressing adenovirus (Ad-β-Gal), and partially restored by infection with PPARα-expressing adenovirus (Ad-PPARα), and (F) respiratory reserve capacity was significantly decreased by 4 hours exposure to 15 μM 4-HNE in Ad-β-Gal infected cells, and restored in 4-HNE-exposed Ad-PPARα-infected cells (β-Gal n = 5, PPARα n = 5, β-Gal + 4-HNE n = 5, PPARα + 4-HNE n = 4). In both experiments, 1 μM oligomycin was injected when indicated in A and D to determine proton leak, 2 μM FCCP was injected as indicated to uncouple (maximize) mitochondrial respiration, and 1 μM antimycin A (AA) was injected at the end of the experiment to arrest mitochondrial respiration. **p≤0.01; ***p≤0.001; ****p≤0.0001, One-way ANOVA with Tukey’s post-hoc comparison.