MAOB and Parkinson disease: Since SH-SY5Y cell lines do not have the enzyme monoamine oxidase-B (MAO-B) necessary to convert MPTP into MPP+ in the brain, this latter metabolite is directly administered, to induce neurotoxicity and to be used as an in vitro model for PD (Sheehan et al., 1997; Xicoy et al., 2017; Risiglione et al., 2020).