Fig. 7.

Wnt1 requires Akt1 to block apoptotic cell death during Aβ_1-42. In A, overexpression of Wnt1 significantly reduces cell injury with significant reduction in trypan blue (TB) staining and nuclear DNA fragmentation (TUNEL), but co-transfection with Wnt1 overexpression and Akt1 siRNA removes protection by Wnt1 and leads to cell injury with increased trypan blue staining and DNA fragmentation. In B, quantification of results in Aillustrate that gene silencing of Akt1 with siRNA (Wnt1/Aβ_1-42Akt1siRNA) significantly prevented the ability of Wnt1 overexpression (Wnt1/Aβ_1-42) during Aβ_1-42 exposure to block cell injury with decreased trypan blue staining and DNA fragmentation with decreased TUNEL labeling (*P<0.01 vs. Aβ_1-42; ^†P<0.01 vs. Wnt1/Aβ_1-42). For B, each data point represents the mean and ±SEM from 6 experiments. In C, the expression of Wnt1 and total Akt1 was observed during Wnt1 overexpression through Western blot analysis. Top panel illustrates that Wnt1 expression is not altered during Akt1 siRNA co-transfection with stable Wnt1 overexpression. In the bottom panel, gene silencing of Akt1 during stable Wnt1 overexpression significantly depresses total Akt1 expression.