Certain inhibitors of synthetic amyloid beta-peptide (Abeta) fibrillogenesis block oligomerization of natural Abeta and thereby rescue long-term potentiation - PubMed (original) (raw)

Hydroxyanaline derivatives RS-0406 and RS-0466 inhibit Aβ oligomerization A, Synthetic Aβ(1-42) was incubated at 100 μ

m

in 50 m

m

Tris-HCl, pH 7.4, at 37°C with and without 0.25 m

m

of each test compound, and aliquots were assayed for thioflavin T binding. RS-0406, OR1, and OR2 each significantly decreased in vitro synthetic fibrillogenesis (*p < 0.05). Error bars represent SD. B, 7PA2 cells were grown to near confluence in 10 cm2 dishes and allowed to condition serum-free medium with and without test compounds [(in μ

m

): 102 RS-0406, 9.3 RS-0466, 18.5 OR1, and 18.5 OR2]. After 15 h, the CM was collected, cleared of cells, and analyzed by IP with R1282 and Western blotting with 6E10. Only RS-0406 and RS-0466 decreased natural oligomer levels. M, D, and T designate Aβ monomer, dimer, and trimer. C, 7PA2 cells were grown to near confluence in 10 cm2 dishes as described in B but labeled with [35S]methionine for 15 h with and without RS-0406 or RS-0466. Thereafter, the CM was collected, cleared of cells, immunoprecipitated with R1282, and analyzed by SDS-PAGE and autoradiography. M, D, and T are as in B. Aβ monomer, 5 kDa Aβ, and p3 (the latter being the proteolytic product of the α- and γ-cleavages of APP) do not appear as discrete bands at the exposure time necessary to visualize Aβ oligomers. Again RS-0466 and RS-0406 decreased oligomer levels. D, 7PA2 cells were grown in the presence or absence of RS-0406 or RS-0466, and lysates were prepared and immunoprecipitated with R1282. Both Aβ monomer (M) and dimer (D) bands are readily detected in lysates from untreated cells (0), but the dimer bands are significantly reduced in lysates of cells grown in the presence of RS-0406 or RS-0466. Because 6E10 also detects the more abundant APP C-terminal fragment, C99, the trimer is not discernible. Both compounds decreased the amount of dimers detected intracellularly. E, 7PA2 cells were grown to near confluence in 10 cm2 dishes as described in B and allowed to condition serum-free medium in the absence of any compounds. After harvesting and removing the cells by low-speed centrifugation, the CM was incubated with and without RS-0406 or RS-0466 for 15 h at 37°C. Neither compound altered the pattern of detection of oligomers, thus confirming that these hydroxyanaline compounds do not act by breaking up preexisting oligomers but rather act by inhibiting oligomerization.