Fig. 4: Cristae integrity and RSCs formation are restored by Ndufs4 overexpression.

Representative TEM micrographs of cristae morphology (a) and quantitative analyses of cristae density (b–d) in podocytes cultured under NG (5.5 mM) or HG (25 mM) for 48hrs with DOX induction (NDUFS4 OE) or without DOX induction (n = 53–61 mitochondria/group, scale bars = 200 nm). IMM inner mitochondrial membrane, OMM outer mitochondrial membrane. e Cryo-ET analysis of purified mitochondria in DOX-inducible Ndufs4 transfected podocytes cultured under NG without DOX, HG without DOX, and HG with DOX induction (NDUFS4 OE). Slices through representative Cryo-ET tomograms are shown in upper panels and corresponding segmentations of characteristic features in lower panels (Scale bars = 200 nm). f Resolution of ETC complexes by BN-PAGE of mitochondria solubilized by digitonin from HG-DOX (control) or HG + DOX (NDUFS4 OE) podocytes. Left panel: Coomassie staining; right panel: Immunoblots with OXPHOS cocktail antibodies. RSC respiratory supercomplexes. g Representative CI in-gel activity of n-Dodecyl β-D-maltoside (DDM)-solubilized mitochondria isolated from the same cells as in Fig. 4f. h Immunodetection of NDUFS4 after SDS-PAGE of mitochondria proteins in cells from Fig. 4f. VDAC was used as a loading control. Data are presented as median ±IQR (Bold line: median, and dot line: IQR). ****P < 0.0001. Kruskal–Wallis with post-hoc Dunn’s test (b–d). Cryo-ET analysis was performed two times and confirmed the reproducibility of cristae morphological change in 5 mitochondria from each group of cells. BN-GEL and the subsequent immunoblot were conducted two times independently to validate the reproducibility. Source data are provided as a Source Data file.