Fig. 2.

Double and triple immunofluorescence for (red) the dopaminergic marker TH (a, d), or the astrocytic marker GFAP (c, f), or the microglial marker Iba-1 (b, e, g–k), or the nuclear marker Hoechst 33342 (i–k; blue), and different transgenes (green; α-syn-WT: a–f; α-syn-A53T: g–k) in the substantia nigra region 4 weeks after the injection of AAV9 expressing human WT α-syn (a–f) or human α-syn-A53T (g–k), respectively. Laser confocal microscopy shows colocalization (yellow) of α-syn with the dopaminergic marker TH (a, d). However, α-syn is not expressed in microglia or astrocytes. Areas squared in (a)–(c) are magnified in (d)–(f). An intense microglial activation is observed in (b) and (e). A microglial cell engulfing α-syn-A53T from a degenerating neuron (arrow) is shown in (g)–(k). Scale bars = 75 μm (a–c), 7.5 μm (d), 5 μm (e–f), and 10 μm (g–k). Abbreviations: α-syn A53T = A53T mutated alpha-synuclein; α-syn WT = wild-type alpha-synuclein; GFAP = glial fibrillary acidic protein; Iba-1 = ionized calcium-binding adapter molecule 1; TH = tyrosine hydroxylase