Figure 5.

SOX10-Induced OLs Myelinate Both Shiverer Mouse Brain Slices and hPSC-Derived Cortical Neurons

(A–E) Confocal microscopy images of O4⁺ purified SOX10-induced cells injected into Shi^−/− mouse brain slices 10 days after injection. (A) Whole-slice image showing homogeneous dispersion of the injected cells (human nuclear antigen, hNA⁺). (B and C) Overview images of slices showing grafting and maturation of the injected cells. (D and E) Detailed images showing MBP⁺ prolongations annealing and ensheathing NF200⁺ neuronal axons.

(F–Q) Confocal and transmission electron microscopy (TEM) images of the co-culture between hPSC-derived neurons and SOX10-induced O4⁺ cells. (F) Overview of the co-culture. (G) Amplification of a representative region with mature OLs extending their processes over neuronal axons. (H and I) Magnifications of an OL showing, at different locations, the complete ensheathment of neuronal axons. (J) 3D reconstruction suggesting the wrapping of axons by an OL. (K) Detailed 3D reconstruction of a region showing complete ensheathment of an axon (red) by MBP⁺ prolongations (green). Nuclei counterstained with Hoechst 33258 (blue). (L) TEM image showing neuronal axons (red) surrounded by an OL (green). (M) Myelin-like structures are found in regions with axon tracts. (N) Magnification of a myelinating structure where compact myelin formation can be observed. (O) TEM example where myelination of a neuronal axon is partially complete (arrow). (P) Detailed micrograph of an OL prolongation (#) starting to form a layered myelin sheet around a neuronal structure (^∗). (Q) Magnification showing the formation of a multilayer compact myelin structure.

Scale bars: 1 mm (A), 50 μm (B and C), 20 and 2 μm inserts (D and E), 2 μm (L), 0.5 μm (M), 100 nm (N), 200 nm (O), 200 nm (P), and 200 nm (Q).