Fig. 3.
Co-treatment of microglia with phen and Aβ peptides activates p44/42 MAPK, resulting in microglial activation. Microglial treatment conditions are indicated and are further described in Materials and Methods. Control peptide is Aβ40-1. Cell lysates were analyzed by Western immunoblotting using specific antibodies that recognize phosphorylated or total p44/42 MAPK.a,b, Phosphorylation and activity of p44/42 MAPK after co-treatment with phen and Aβ peptides.c,d, Inhibition of this effect by PD98059 (a specific MEK1/2 inhibitor). Histograms below the immunoblots represent the mean band density ratio ± 1 SEM (phospho-p44/42 MAPK/total p44/42 MAPK) and band density in optical density units (phospho-Elk1), respectively (n = 3 for each condition presented). Microglial activation is evidenced by mean TNF-α release ± 1 SEM (picograms per milligram of total protein) (e) and mean NO release ± 1 SEM (micromolar concentration per milligrams of total protein) (f) in cultured media by ELISA or by NO release assay, respectively (n = 3 for each condition presented). Fora and b, ANOVA revealed significant main effects of phen, Aβ1-40, and Aβ1-42(p < 0.001), and there were significant interactive terms between phen and either Aβ1-40 or Aβ1-42 (p < 0.001). One-way ANOVA revealed significant between-group differences (p < 0.001), and post hoctesting showed significant differences between Aβ1-40 and phen/Aβ1-40 (p < 0.001) and between Aβ1-42 and phen/Aβ1-42(p < 0.001). Forc–f, one-way ANOVA revealed significant between-group differences (p < 0.001), and post hoc testing showed significant differences between phen/Aβ1-40 and phen/Aβ1-40/PD98059 (p < 0.01) and between phen/Aβ1-42 and phen/Aβ1-42/PD98059 (p < 0.01).