Figure 7.

PBEF inhibitor FK866 induces neuronal atrophy in cultured hippocampal neurons (A and B) The effects of FK866 on cellular NAD and ATP levels. Mature hippocampal neurons (DIV = 22) were treated with FK866 at different concentration, and collected at indicated time-points post-KF866 treatment for HPLC analysis. The NAD and ATP levels were expressed as percentages of the control groups without treatment. (C) Representative confocal images showing that FK866 treatment induces decreases of dendritic spines and dendritic branching in hippocampal neurons. DIV 25 neurons were treated with FK866 (10 nM) alone, or FK866 (10 nM) together with NAD (5 mM) for three days. To visualized individual neurons, the same cultures were transfected with enhanced GFP expressing plasmids by the calcium phosphate transfection method. Hippocampal neurons were cultured at a high density (about 1,000 neurons per mm²). Transfection efficiency is less than 0.1%. The top panel shows the representative higher magnification views of dendritic segments (Scale bar: 5 µm). The bottom panel is the representative images of whole the entire neuron showing dendritic branching patterns (Scale bar: 50 µm).