Fig 2: OPA1 loss leads to induction of ER stress markers and changes in the levels of cleaved caspases. a Percentage of annexin V+MCAS cells transduced with a control targeting sgRNA or a sgRNAs targeting OPA1 (n = 3). Data are mean ± SEM. *p < 0.05 by Student’s t-test. b Ratio of JC-1 fluorescence (595 nm/535 nm) in MCAS cells transduced with control sgRNA or three independent sgRNAs for OPA1 (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. c Left, DCFDA raw fluorescence units minus no stain fluorescence units in MCAS cells transduced with control sgRNA or three independent sgRNAs for OPA1 (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. Middle, DAF-FM raw fluorescence units minus no stain fluorescence units in MCAS cells transduced with control sgRNA or three independent sgRNAs for OPA1 (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. Right, mitosox raw fluorescence units minus no stain fluorescence units in MCAS cells transduced with control sgRNA or three independent sgRNAs for OPA1 (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. d Immunoblot of indicated proteins from the UPR and apoptosis pathways in MCAS cells transduced with control sgRNA or three independent sgRNAs for OPA1. Immunoblots are representative of three independent experiments. e Log2(sgOPA1/sgCTRLA1) BV6 GI50 value in MCAS cells treated with either vehicle or one of the following: NaC (10 mM), Tiron (1 mM), and Carboxy-PTIO (100 µM) (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. f Log2(sgOPA1/sgCTRLA1) BV6 GI50 value in MCAS cells treated with either vehicle or Q-VD-OPh (20 mM) (n = 3). Data are mean ± SEM. *p < 0.05 by one-way ANOVA. g Log2(sgOPA1/sgCTRLA1) BV6 GI50 value in MCAS cells treated with either vehicle or one of the following: Tudca (500 µM) or GSK2606414 (1 µM) (n = 3). Data are mean ±SEM. *p < 0.05 by one-way ANOVA. h Immunoblot of indicated proteins in MCAS cells transduced with control sgRNA or two independent sgRNAs for OPA1 treated with vehicle, QVD, Tudca, or NaC at indicated doses. Immunoblots are representative of two independent experiments. i Model of SMAC mimetic sensitivity in OPA1 or DNM1L loss cells

Fig 3: Administration of Fn1 inhibitor increased the AMP/ATP ratio and activated LKB1-AMPK signaling in I/R hearts. (a) Immunoblotting analysis of the protein levels of p-LKB1 (S428), LKB1, p-AMKP (T172), AS160, GLUT4, Mfn1, Mfn2, (left), p-Drp1 (S616), and Drp1. GAPDH as an internal control. (b) The quantification of the relative protein levels (right, n = 4 per group). (c) Measurement of AMP and ATP contents and the ratio of AMP/ATP (n = 5). Data are expressed as mean ± SEM. ***P < 0.001; ****P < 0.0001 versus the sham-operated group; ##P < 0.01; ###P < 0.001, ####P < 0.0001 versus saline I/R 24 h; &&P < 0.01; &&&P < 0.001, &&&&P < 0.0001 versus saline I/R 72 h.

Fig 4: Potential mechanism of RACGAP1P implicated in breast cancer invasion and metastasis. In breast cancer cells, RACGAP1P could competitively bind to miR-345-5p that targeted RACGAP1 therefore up-regulate RACGAP1. RACGAP1P overexpression promoted mitochondrial fission mediated cell invasion via RACGAP1P/miR-345-5p/RACGAP1/Drp1 network.

Fig 5: Cold-induced mitochondrial fission despite the presence of the Drp1 inhibitor Mdivi-1. Porcine aortic endothelial cells (control, A, I) were incubated at 4 °C for 3 h, 6 h and 24 h with 20 µM Mdivi-1 (E–H, M–P), a potent Drp1 inhibitor. DMSO was added as solvent control (A–D, I–L). Mitochondria were stained with MitoTracker Red. Additionally, Drp1 immunofluorescence (green) staining was applied (I–P). The images were documented by fluorescence microscopy (MitoTracker Red: ?exc. = 546 ± 6 nm, ?em. = 590 nm; FITC: ?exc. = 470 ± 20 nm, ?em. = 525 ± 25 nm). Representative figures of n = 4 experiments. For quantification of mitochondrial fission (Q) cells were categorised in cells with predominantly short, intermediate and long mitochondria by a person blinded to the experiment. Means ± SD of n = 4 experiments