FHC silencing abrogates the effect of gp120 on spines. A, Analysis of control and gp120 (either IIIB or BaL, 200 pm; 24 h)-treated cocultures shows a significant negative correlation between the FHC relative expression of each neuron [i.e., relative fluorescence units (RFU)] and their dendritic spine density (n = 15, Pearson's r = −0.7441, p = 0.0015). B, The ability of gp120IIIB to regulate dendritic spine density was blocked in FHC-deficient neurons, as shown using FHC-specific or scrambled control shRNA (n = 12). Veh, Vehicle. Blue symbols denote significance; ***p < 0.001.