SIRT1 deacetylase activity regulates dendritic arbor complexity in hippocampal neurons.

<p>Neurons at 3 DIV were transfected with EGFP, SIRT1/EGFP or SIRT1H363Y/EGFP, then were treated at 4 DIV with Res (1, 10 or 50 µM), fixed at 6 DIV and immunostained against MAP-2 for dendrite analysis. (<b>A</b>) Representative images of control neurons transfected with EGFP (left column), SIRT1/EGFP (middle column) or SIRT1H363Y/EGFP (right column) and treated with different concentration of Res. Scale bar, 10 µm. (<b>B, C</b>) Quantification of TDBTN (B), and coverage area (C) in the presence or absence of different concentrations of Res (1, 10 or 50 µM). Ten fields were randomly selected photography. Values were normalized against control neuron transfected with EGFP. (<b>D</b>) Sholl analysis of neurons tansfected with GFP (black circles), GFP + Res 10 µM (white circle), SIRT1/GFP (red triangle) or SIRT1/GFP + Res 10µM (blue triangle). Both, Res treatment and SIRT1 transfection significantly increases the number of intersection at 25–80 µm from the soma (p<0.01 at 25–80 µm) and a higher increase in the number of intersection at 40–90 µm from the some (p<0.001 at 40–90 µm). (<b>E</b>) Sholl analysis of neurons transfected with the dominant negative of SIRT1. EGFP (black circles), SIRT1H363Y/EGFP (white circle), SIRT1H363Y/EGFP + Res (red triangle). SIRT1H363Y/EGFP transfection significantly decreased the number of intersection at 28–45 µm from the soma compared to control EGFP trasfected neurons (p<0,01 at 28–45 µm), and it prevented the effect of Res. Experiments were made triplicate and <i>p</i> values were determined by Kruskal-Wallis/Dunn. Error bars indicate S.E.M. n = 50–60 neurons. *p<0.01; **p<0.001.