Metabolomic analysis of mitochondrial stress. (A) Multidimensional scaling (MDS) using the unique metabolites identified. Metabolome pathway enrichment of (B) up-regulated and (C) down-regulated metabolites upon mitochondrial stress. Scatterplots represents p-values from integrated enrichment analysis and impact values from pathway topology analysis. The node color is based on the p-values and the node radius represents the pathway impact values. (D) Dot plot representing the fold change of the top changed metabolites in each mitochondrial stress condition. Fold change is represented in log scale and all metabolites show significant differences with an FDR <0.05. (E) Box-whisker plots representing the ratio of serine and phosphoserine levels in each mitochondrial stress condition. (F) Graphical representation of enzymes and metabolites of the glutathione (GSH) cycle. Enzymes and metabolites highlighted in red are up-regulated upon mitochondrial stress, whereas those in blue are down-regulated. (G and H) Box-whisker plots representing the levels of (G) oxidized glutathione (GSSG) and the ratios of GSH to GSSG (GSH/GSSG) and (H) GSH to cysteine glutathione disulfide (GSH/CYSSG). **, P < 0.01; ***, P < 0.001. Acti, actinonin; CE, cholesterol ester; DG, diacylglycerol; Dox, doxycycline; MB, MitoBloCK-6; MG, monoacylglycerol; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PS, phosphatidylserine.