Loss of Pgrn decreases neurite outgrowth and branching in primary neurons. (A) Western blot analysis reveals endogenous levels of Pgrn in WT and Grn−/− primary hippocampal cultures. (B) WT and Grn−/− hippocampal neurons immunostained for MAP2. (C-E). Neurite outgrowth and branching of MAP2-immunopositive neurons was assessed using MetaMorph version 7.1 software. Note that neurite outgrowth (C) and branching (D), but not cell body size (E), are decreased in Grn−/− hippocampal neurons compared to WT hippocampal neurons. All data is presented as the mean ± SEM. **p < 0.01; ***p < 0.001.