Additionally, to address the role of megalin in pathological toxic conditions, we subjected TTR KO and Meg+/− TTR KO neurons to excitotoxic conditions, consisting of a transient incubation with a high glutamate concentration (125 μM, 20 min), an in vitro model of neuronal death in cerebral ischaemia/stroke (Dwyer et al., 2008), and further incubation in culture-conditioned medium for 14 h (40–50% apoptotic neuronal death) (Almeida et al., 2005). Here, PTPN4 is linked to Stroke.