GDNF and Parkinson disease: Given that α-synuclein intercepts Ret/GDNF-signaling in dopaminergic neurons (Decressac et al., 2012), while GLP-1R activators were shown to prevent the accumulation of soluble, insoluble and phosphorylated α-synuclein species in PD in vivo models (Yun et al., 2018; Zhang et al., 2019; Lv et al., 2021; Zhang L.Y. et al., 2021), GLP-1 mimetics might be a safer, easier administrable and more effective alternative to endogenous GDNF treatment.