GFAP and Parkinson disease: Accordingly, we show that MPTP treatment depleted TH protein expression and increased expression of glial fibrillary acidic protein (GFAP), an astrocyte marker that is upregulated in human PD patients (Clairembault et al., 2014), in the midbrain and striatum of WT control mice, as evidenced by results from western blot analysis (Figure 2a, left panel, quantified in Supporting Information Figure S1a,c,e).