Fig. 1: The combination of Aβ accumulation and MITOL loss enhances mitochondrial dysfunction.
a–d MITOL was downregulated by Aβ in the model mice and cells. Brain lysates were solubilized from the cerebral cortex of indicated mice at 15 months of age, followed by immunoblotting with indicated antibodies (a). Indicated mRNA levels in the cerebral cortex of indicated mice were measured by qRT-PCR (b). SH-SY5Y cells stably expressing APPswe were transfected with siPS1 48 h before each analysis (c, d). As control cells, SH-SY5Y without stable expression were transfected with scramble siRNA instead of siPS1. These cell lysates were immunoblotted with indicated antibodies (c) or analyzed by qRT-PCR (d). Error bars indicate ±SE (b: n = 3–5, d: n = 4). *p < 0.05 (Student’s t test). Non-Tg.: Non-transgenic MITOLF/F mice. APP/PS1: MITOLF/F APP/PS1 mice. e–h MITOL loss accelerated mitochondrial dysfunction in the model mice. The brain of indicated mice at 15 months of age was subjected to transmission electron microscopy (TEM) analysis (e–h) or COX staining (i). The lower panels show high-magnification images of the boxed regions (e). Arrowheads indicate neurons (i). The scatter dot plot indicates mitochondrial area. Horizontal bar, median; box limits, 25th and 75th percentiles; whiskers, 10th and 90th percentiles (f: n = over 300 mitochondria in the cell body of neurons of the cerebral cortex). The morphology of mitochondrial cristae is classified as normal (Class I) or abnormal (Class II, III) (g, h). Mitochondria of indicated groups are distinguished into three types (h: n = over 300 mitochondria in the cell body of neurons of the cerebral cortex). Scale bar represents 500 nm (e, g), 200 µm (i: upper panels), 20 µm (i: lower panels). In vitro mitochondrial ATP, production assay was performed as described in the method. Error bars indicate ±SE (j: n = 4–6). ***p < 0.001, **p < 0.01 (one-way ANOVA, Tukey’s test).
