HSF1 and Huntington disease: Importantly, we tested the expression levels of HSF1, Hsp70, CK2α′ and Fbxw7 in human HD induced pluripotent stem cells (iPSC)-derived MSNs from 33Q (Control) and 60Q (HD) containing allele individuals in the absence or presence of brain-derived neurotrophic factor (BDNF; Fig. 6b).