One cytotoxic study of NiO-NPs against SH-SY5Y determined by caspase-9/3 activity, and expression of apoptotic Bax and Bcl-2 genes assays, demonstrated a significant increase in the mortality of SH-SY5Y cells in an apoptotic fashion suggesting that NiO-NPs may mediate the formation of electrostatic interactions with tau proteins and induction of untoward effects on neurons (Hajimohammadjafartehrani et al., 2019, Alquezar et al., 2020) examined the neurotoxic effect of nickel in Progressive supranuclear palsy (PSP) cases using two different human cell models. This evidence concerns the gene CASP9 and progressive supranuclear palsy.