Figure 3.
Wnt1 signaling is necessary for neuronal protection against OGD. In A, increasing concentrations of Wnt1 protein result in significantly increased neuronal survival assessed by trypan blue exclusion 24 hours after OGD (*p < 0.01 vs. OGD). In B, increasing concentrations of an antibody to Wnt1 (Wnt1Ab) during OGD do not alter neuronal survival assessed by trypan blue exclusion 24 hours after OGD when compared to neurons exposed to OGD alone. In C, increasing concentrations of an antibody to Wnt1 (Wnt1Ab) applied with Wnt1 (100 ng/ml) resulted in progressive loss of Wnt1 protection and increased neuronal cell injury assessed by trypan blue staining 24 hours after OGD (*p < 0.01 vs. OGD). In D, inhibition of Wnt1 signaling with DKK-1 (0.5 µg/ml), an antagonist of the Wnt/β-catenin pathway, administered with Wnt1 (100 ng/ml) significantly reduces protection by Wnt1 and neuronal cell survival assessed by trypan blue staining 24 hours after OGD (*p < 0.01 vs. OGD; †p < 0.01 vs. Wnt1/OGD). In all cases control = untreated neurons. Each data point represents the mean and SEM from six experiments.