Fig 2: Effect of Lenti-Drp1-S579A on Aß1–42-induced neurite alterations under phase-contrast microscope. (A) Representative images of primary cortical neurons under phase-contrast microscope. Neurons were incubated with or without 10 µM Aß1–42 for 24 h. To examine the effect of phosphorylation-defect Drp1 on Aß1–42-induced alterations in neurons, Lenti-Drp1-S579A was infected to cells at 3 days prior to Aß1–42 stimulation (magnification, 20). Scale bar, 50 µm. Effect of Lenti-Drp1-S579A on Aß1–42-induced neuronal alterations. The graphs indicate (B) neurite length and (C) dendrite number in primary cortical neurons in each group. **P<0.01. Drp1, dynamin-related protein 1; Cont, control; Aß, amyloid ß.

Fig 3: Akap1 deletion decreases the phosphorylation of Drp1 at Ser637 under oxidative stress without affecting other fission or fusion protein expression. (A) Representative Western blot of total Drp1 and phosphorylated Drp1 (pS637) expression in the lung lysates derived from Wt and Akap1 -/- mice exposed to normoxia or hyperoxia. Total Drp1 and pDrp1/Total Drp1 expression were quantitated after normalization with ß-Actin control. Data represented as mean ± SEM. n = 5 mice per group. One-way ANOVA and post-hoc Tukey test. *p < 0.05 Wt hyperoxia versus Wt normoxia. **p < 0.01 Akap1 -/- hyperoxia versus Wt hyperoxia control. (B) Representative Western blots of Fis1, Mfn1 and Opa1 expression in the lung lysates derived from Wt and Akap1 -/- mice exposed to normoxia or hyperoxia. (C–E) Quantitative expression of Fis1, Mfn1 and Opa1 after normalization with ß-Actin control. Data represented as mean ± S.E.M. n = 6 mice per group. NO = normoxia. HO = hyperoxia.

Fig 4: Schematic illustration of cadmium-induced toxicity in TM3 cells.Cadmium causes mitochondrial dysfunction and promotes excessive mitochondrial fission by controlling the expression of mitochondrial dynamics regulatory proteins (DRP1, FIS1, MFN1 and OPA1). Consequently, cytochrome c is released from the mitochondria to cytosol and the mitochondria-dependent intrinsic apoptosis of TM3 cells is induced. Moreover, cadmium probably disrupts calcium homeostasis and inhibits autophagic flux in the cells. The blocking of Parkin recruitment into damaged mitochondria by cadmium results in inhibition of mitophagy, production of excessive ROS and cell death.

Fig 5: Cadmium induced mitochondrial fragmentation and dysfunction in TM3 cells.A, B Mitochondria were stained with Mito-Tracker Red CMXRos after the cells were treated with cadmium. The mitochondrial morphology factors (aspect ratio and form factor) were evaluated. C The percentage of cells containing tubular or fragmented mitochondria was calculated. D The protein levels of FIS1, DRP1, OPA1 and MFN1 were measured by Western blot after treatment with cadmium. E The effects of cadmium on mitochondrial Ca2+ levels and expression of mitochondrial calcium uniporter (MCU) were analyzed by immunofluorescence and Western blot, respectively. F The effect of cadmium on mitochondrial ??m was assayed by JC-1 staining. G Luciferase-based assays were used to determine cellular ATP production. The data represent the mean ± SD of three independent experiments (*P < 0.05, **P < 0.01, ***P < 0.001, ###P < 0.001, ****>P < 0.0001, ####P < 0.0001 vs. control).