Studies in AD mice or primary hippocampal neurons treated with 17-AAG, an HSP90 inhibitor that leads to activation of HSF1, resulted in increased expression of PSD-95 as well as the pre-synaptic proteins Synapsin I and SYP1, and BDNF (brain-derived neurotrophic factor) [5]. This evidence concerns the gene HSF1 and Alzheimer disease.