Extended Data Fig. 7: Reducing Q levels as a strategy to counteract reductive stress resulting from dysfunctional ETFDH.
a) Left panel, schematic represents the metabolon. Right panel, proteomic analysis of 26 bands from 1D-BN-PAGE immunoblots of mitochondrial membrane proteins from wt mouse hearts and wt, Mt-Cyb-/- and ρ0 mouse fibroblasts. White to brown scale indicates the abundance of the protein within a band. ETFDH was found to comigrate with CIII and COQ2 within the band 13 in basal conditions. b) Mitochondrial ROS in the presence or absence of riboflavin (rib) in control (CRL) and patient-derived fibroblasts (M2, M3, M4, M9). n = 3. c) Mitochondrial ROS in the presence or absence of the COQ2 inhibitor 4-CBA in control (CRL), ETFDH-ko and double COQ2-ko, ETFDH-ko myoblasts. n = 3. d) Representative respiratory profile of control (CRL, gray traces) myoblasts treated or not with different doses of 4-CBA. OCR, oxygen consumption rate; OL, oligomycin; FCCP; Rot, rotenone; Ant, antimycin A. Glucose was used as a substrate. 10 replicates/condition. e, f) Total Q9 levels in control in wt and ETFDH-ko myoblasts treated or not with 4-CBA. n = 3. g) Q9H2/Q9 ratio in control in wt and ETFDH-ko myoblasts treated or not with 4-CBA. n = 3. Results are shown as the mean ± SEM of the indicated n. *, **, ***, **** p < 0.05; 0.01, 0.001 and 0.0001 when compared to CRL by two-tailed Student’s t-test (b, e, f), one-way ANOVA with Tukey’s test (g), and two-way ANOVA with Dunnett’s test (c).
