Figure 1.

Intracerebral grafting of brain organoids into mouse brain. (a) Illustration of the experimental procedure for generation of GFP+ organoids from hESCs and intracerebral implantation into immunodeficient mouse brain. (b) Whole-mount dorsal view image of mouse brain grafted with a GFP+ cerebral organoid and harvested at 50 dpi; the graft is outlined in white. Right, magnified graft displaying neurite outgrowth from the organoid toward the host brain (arrowheads). (c) Kaplan–Meier survival curve for overall survival of mice after engraftment with brain organoids. (91.8% survival beyond 180 dpi, n = 61 mice from ten experiments). (d) GFP+ organoids were grafted into mouse brain and harvested at the indicated dpi. Coronal sections were analyzed using immunofluorescence and confocal microscopy. Immunofluorescence staining for GFP and human nuclear antigen (hNuclei), demonstrates that the implant survived well and distributed throughout the lesion cavity at 14 dpi. Left image shows confocal stitched tile scan; image was vertically inverted. White solid lines indicate apical/ventricular surface. Dotted white line indicates the radial glia VZ-L regions. Yellow lines indicate the graft-host border. (e) Graft immunostained for GFP, dorsal telencephalic progenitor marker PAX6 and the deep-layer subcortical neuron marker CTIP2. Radially organized cells (arrowhead, left panel) represent the PAX6+ VZ-L region (dotted white lines). n = 4 animals in b, and n = 3 animals in d,e. Nuclei were counterstained with DAPI. Scale bars: 1 μm in b, 100 μm in d, and 20 μm in e.