MPTP-induced PD C57BL/6 mice activated astrocytes of the ventral midbrain (GFAP+) and primary astrocytes from mouse ventral midbrain and aNPCs from subventricular zone and midbrain co-culture (treated with MPTP and the Wnt inhibitor Dkk-1). The gene discussed is DKK1; the disease is Parkinson disease.