IL3 and Parkinson disease: In this study, astrocytic IL‐3 and microglial IL‐3R were found to be responsive to α‐synuclein pathology in the brains of transgenic A53T PD mice and in an adeno‐associated virus (AAV)‐human α‐synuclein (AAV‐hα‐Syn)‐injected PD mouse model.