RU-505 inhibited the Aβ–fibrinogen interaction and restored Aβ-induced altered fibrin clot formation and degradation. (A) Candidate compounds (10 µM) were incubated with biotinylated Aβ42 and fibrinogen, and pull-down assays were performed using streptavidin–Sepharose. All samples were analyzed by Western blot. Dot blots were performed to control for amounts of Aβ pulled down. Control (Ctrl) lane contains only Aβ and fibrinogen without any compound (one-way ANOVA and Bonferroni post-hoc test; *, P < 0.05; n = 3–4 independent experiments). (B) The binding affinity between fibrinogen and monomeric or oligomeric biotinylated Aβ42 was measured using the AL assay. (n = 3–4 experiments, data are representative of three independent experiments). (C) The inhibitory efficacy of RU-505 on the interaction between fibrinogen and monomeric or oligomeric biotin-LC-Aβ42 was accessed in dose–response experiments using the AL assay. (n = 3–4 experiments, data are representative of three independent experiments). (D) RU-505 or DMSO was incubated with fibrinogen in the presence or absence of Aβ42, followed by plasminogen, thrombin, tPA, and CaCl2. Fibrin clot formation was assessed by measuring turbidity (n = 3 experiments, data are representative of three independent experiments). (E and F) The time to fibrin clot degradation was analyzed by measuring time to half lysis. Control clot half lysis time was set to 100% for each experiment and all other values were calculated relative to controls. (***, P < 0.001; n = 3 experiments, data are representative of three independent experiments). (G and H) Aβ42 was immobilized on the SPR sensor chip surface, and the interaction of the indicated compounds with Aβ42 was analyzed using Biacore 3000. Sulindac sulfide (known to bind Aβ42) was a positive control, and sulindac was negative control. (H) Chemical structure of RU-4180. Data are representative of three to four independent experiments. All values are means and SEM.