Co-incubation with Photo-oxidized, DiY-Cross-Linked Aβ Assemblies Slows the Aggregation of Freshly Prepared Aβ
(A) DiY fluorescence was measured for freshly prepared Aβ (40 and 20 μM) and Aβ+UV:Aβ (20 μM: 20 μM) mixture immediately after co-incubation of freshly prepared Aβ with DiY-cross-linked Aβ. DiY signal was not detected in unoxidized freshly prepared 40 and 20 μM Aβ but was induced in 2 h UV-oxidized (Aβ+UV) samples and in the mixture.
(B) Th-T fluorescence showed that the unoxidized 40 and 20 μM Aβ assemble at different rates, which was significantly delayed for Aβ+UV:Aβ-UV mixture and completely absent in the oxidized 40 and 20 μM Aβ samples.
(C) TEM imaging at 4 days revealed the presence of fibrils in both unoxidized 40 and 20 μM Aβ, which was significantly reduced in the Aβ+UV:Aβ-UV mixture and absent in the oxidized 40 and 20 μM Aβ samples. A minimum of three independent experiments was repeated to ensure the reproducibility of the findings. Scale bars, 500 nm.