Effects Of Peptides P1 Through P10 On Aβ40 and 42 Production <i>In Vitro</i>.

<p>A and B. Peptides P1(residues 1–80 of PS-1), scrambled P1 (SP1), P2 (residues 1–40 of PS-1) and P3 (residues 41–80 of PS-1) (0–5 μM) were added to cultures of IMR-32 cells for 24 h and the culture media were analysed for Aβ40 (A) and Aβ42 (B) by ELISA. Aβ levels in pg/ml were expressed as a percentage of levels observed in the absence of added peptide. Values represent group means of 3–4 independent experiments per peptide ±s.e.m. Only P3 produced a clear dose-dependent decrease in both Aβ40 and -42, shown in red. C and D. Overlapping peptides from the P3 region (P4–P10) (0–5 μM) were next tested in IMR-32 cultures as in A and B above for their effect on Aβ40 (C) and -42 (D) production. A family of peptides, P6, P7 and P8 and an independent peptide, P4, produced substantial dose-dependent reduction in Aβ40 and 42, shown in red.