Fig. 4: MITOL deletion increases toxic Aβ oligomer partly via the enhanced seeding activity of Aβ fibrils, leading to a higher neuronal injury. | Communications Biology

Fig. 4: MITOL deletion increases toxic Aβ oligomer partly via the enhanced seeding activity of Aβ fibrils, leading to a higher neuronal injury.

From: Mitochondrial ubiquitin ligase alleviates Alzheimer’s disease pathology via blocking the toxic amyloid-β oligomer generation

Fig. 4

a–c MITOL deletion increased soluble Aβ oligomers. The TBS-soluble fraction was isolated from the cerebral cortex of indicated mice at 15 months of age to performed ELISA measurement of Aβ42 (a), Aβ40 (b), and Aβ oligomers (c). Error bars indicate ±SE (a–c: n = 3–6). ****p < 0.0001, **p < 0.01, *p < 0.05 (Student’s t test). d Aβ fibrils containing the plaques from the MITOL-deleted APP/PS1 brain exhibited a dramatic seeding effect on the oligomerization of free Aβ monomers. Aβ fibrils in indicated 15-months old mice were isolated and purified as described in “Method”. The fibrils were co-incubated with seed-free Aβ40 monomers as aggregation seeds for indicated periods as described in “Method” and the oligomerization was monitored by Bis-ANS. As a control, TBS solution was used (no seeds). Error bars indicate ±SE (n = 5). **p < 0.01, *p < 0.05, n.s.: not significant (Student’s t test). e, f Aβ fibrils from MITOL-delated APP/PS1 boosted the neurotoxicity of free Aβ monomers. Purified amyloids of indicated mice were co-incubated with or without seed-free Aβ40 monomers for 24 h as described in “Method”. These co-incubated solutions were added into the growth medium of SH-SY5Y cells at the 25 µM final concentration of Aβ40. After 48 h, dead cells were detected by LDH release assay (e) and Caspase-Glo 3/7 assay, respectively (f). Error bars indicate ±SE (n = 5). *p < 0.05, n.s.: not significant (Student’s t test). g–i RFP injection ameliorated the severe neurological and cognitive symptoms in MITOL-deleted APP/PS1 mice. RFP was treated as described in “Method”. As a control, the solvent for RFP was also treated (Mock) (g–i). The hippocampus of indicated mice at 15 months of age was analyzed by immunoblotting (g) and immunostaining (h), respectively, using indicated antibodies. Barnes maze test was performed to evaluate learning memory of indicated mice at 15 months of age (i). Error bars indicate ±SE (n = 6–7). *p < 0.05 (Student’s t test).

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