Opposing Effects of Sirtuins on Neuronal Survival: SIRT1-Mediated Neuroprotection Is Independent of Its Deacetylase Activity
Figure 3
Pharmacological modulators of SIRT1 activity have no effect on neuroprotection.
(A) Neurons treated with nicotinamide. CGNs were transfected with Flag-tagged SIRT1 or GFP control vector and the cultures switched to LK medium or LK-medium supplemented with 5 mM nicotinamide. Viability of transfected neurons (detected by Flag immunocytochemistry) was quantified 24 hours later (* indicates p<.05 compared with GFP LK; # indicates p<.05 compared with GFP HK). (B) Sirtinol does not affect SIRT1 protection. Flag-tagged SIRT1 and GFP vectors were transfected into CGNs. The neurons were then treated with LK medium or LK-medium supplemented with 100 µM sirtinol. Survival for SIRT1-transfected neurons was assessed using immunocytochemistry and DAPI staining 24 hours following treatment (* indicates p<.05 compared with GFP LK; # indicates p<.05 compared with GFP HK). (C) Resveratrol cannot rescue neurons in LK. Cultured CGNs were switched to HK medium, LK medium, or LK medium containing 10 or 30 µM resveratrol. Neuronal viability was quantified 24 hours later by DAPI staining.