Fig. 4: Migrating neurons in CS-rich injured cortex collapse their growth cones.

a Schematic image shows coronal brain section with neurons (green) migrating from the V-SVZ toward the injured cortical layers (brown) through the corpus callosum (CC). The scale indicates the distance from dorsal V-SVZ used in (d) and (e). b–d A Z-stack projection image of Dcx-EGFP+ cells (green) and CS (red) in a P9 injured brain section including V-SVZ, corpus callosum (CC), and cortex. The representative extended growth cone morphology (c) and collapsed morphology (d) of Dcx-EGFP+ cells in CS-induced injured cortex. e A representative image of Dcx-EGFP+ cells (green) expressing PTPσ (red) in the P14 injured cortex. The boxed area is enlarged. f Relative intensity of CS signal in the P9 injured cortex (0 to <100 μm, 100 to <300 μm, and 300 ≤ μm from the dorsal V-SVZ) was analyzed. The intensity in the area within 100 µm from the dorsal V-SVZ was set as 1. g The percentage of extended growth cones of observed Dcx-EGFP+ cells in the P9 injured cortex (0 to <100 μm, 100 to <300 μm, and 300 ≤ μm from the dorsal V-SVZ). h, i Representative three-dimensional constructions of migrating neurons (green) in the P9 injured cortex analyzed by SBF-SEM. Yellow represents nuclei. Extended (h) and collapsed (i) growth cones are shown. Boxed areas are enlarged. Arrows and arrowheads indicate filopodia and lamellipodia, respectively. Interactive 3D models of neurons are shown at https://sketchfab.com/3d-models/migratory-neuron-with-extended-growth-cone-b6c4b616f56343929cab8e3edca1c884 (h) and https://sketchfab.com/3d-models/migratory-neuron-with-collapsed-growth-cone-70648b036df64a01a30339717b22537f (i). j Time-lapse images of a slice cultured P8 Dcx-EGFP injured cortex section. A Dcx-EGFP+ cell migrates towards the injured site and the growth cone changes direction during the migration. Boxed areas are enlarged and shown on the right panels. Scale bars: b, 100 µm; c, d, e, 10 µm; j, 5 µm. *p < 0.05, **p < 0.01. Error bars indicate mean ± SEM.