Figure 9.

Sirt6 overexpression ameliorates synaptic dysfunction in chronic sleep deprived mice.

(A) Left: Representative images of co-stained eGFP (green) and VGULT1 (Cy3, red) in PrL neurons among the three groups. The presynapses (VGULT1, a pre-synaptic protein) might have been diminished by chronic sleep deprivation, and then recovered by Sirt6 overexpression. Right: Summarized data for eGFP⁺ VGULT1⁺ numbers per 100 µm² (n = 3/group). (B) Left: Illustrations of the virus injection. Middle: Remodeling of randomly selected neurons co-stained with eGFP and RFP, which were further subjected to dendritic spine density analysis. Representative images of neuronal dendrites by sparse labeling among the three groups. Chronic sleep deprivation reduced the number of spines, and overexpression of Sirt6 reversed this reduction. Right: Summarized data for spine numbers per 10 µm. (C) Representative traces (left) and summarized data regarding mEPSCs amplitude (middle) and frequency (right) from eGFP⁺ neurons in the PrL among the three groups (3–4 cells/per mouse). (D) Left: Trains of APs evoked by depolarizing current steps of 100, 200, and 300 pA. Right: Mean frequency of AP firing at each depolarizing current step for eGFP⁺ neurons among the three groups (3–4 cells/per mouse). Data are presented as mean ± SEM, and were analyzed by a two-way analysis of variance followed by Tukey’s post hoc test. AP: Action potential; CSD: chronic sleep deprivation; DAPI: 4′,6-diamidino-2-phenylindole; eGFP: enhanced green fluorescent protein; mEPSC: miniature excitatory postsynaptic current; RFP: red fluorescent protein; Sirt6: Sirtuins 6; VGLUT1: vesicular glutamate transporter 1.