In this study, we determined whether inhibitors of different HDAC classes would enable the heat shock response in motor neurons and would improve the efficacy of HSP-inducing drugs in experimental models relevant to ALS, using four experimental paradigms:Induction of Hsp70 by the HSP90 inhibitor, NXD30001: HSP90 inhibitors constitutively induce expression of HSPs by disrupting HSP90 complexes; HSP90 also participates in the removal of HSF1 trimers from HSE, such that HSP90 inhibitors prolong the HSF1-HSE interaction (Kijima et al. 2018). This evidence concerns the gene HDAC9 and amyotrophic lateral sclerosis.