Fig. 4: Perinatal ISR^mt induction pro-ferroptotic signaling fatally disrupts cardiomyocyte metabolic maturation.

a Illustrative ferroptosis-related pathways colored by their proteomic (normal font) and metabolomic (italics) changes in P1 hearts. b Pie charts of ferroptosis involvement (FerrDb marker/suppressor or KEGG pathway) in Polg^MutTwOE vs WT (n = 6 + 5), by significant change (Qval<0.01) in P1 heart proteomics, colors as in (a). c Time-course cell death assay for RSL3 sensitivity titration, point-error plot indicating mean and standard error of each time point (n = 3 + 3 cell lines derived from separate mice). d Ferroptosis sensitivity assay showing differential response to RSL3 and rescue by Fer-1, data from t = 6 h. e Venn diagram of significantly changed genes (FDR-corrected p value > 0.01) per genotype against WT (n = 4) in E16.5 transcriptomics, with detailed highlighted overlaps. f Scatterplot of Polg^Mut vs Polg^MutTwOE p-values (against WT) from E16.5 transcriptomic analysis, highlighting Hddc3 in red. P values derived from multiple testing-corrected Wald test, as described in the methods. g, h Relative heart Hddc3 mRNA (g, E16.5) and MESH1 protein (h, P1, n = 5 + 1 + 6) amounts from omics data. i Relative Hddc3 mRNA amount by RT-qPCR from control and siRNA-treated MEF cells (n = 3 for all groups). j Ferroptosis sensitivity and rescue assay in control and siRNA-silenced cells, data from t = 6 h, n = 24 (untreated controls) + 18 (all other groups). Individual data points overlaid on summarized mean and standard error bars, p values from two-sided t-test unless otherwise stated: (p < 0.05*, 0.01**, 0.001***).