Figure 4. Myelination by Adult-Transplanted hGPCs Restores Function in shiverer Mice.

(A) Mice were injected bilaterally in the corpus callosum and striatum at 4 weeks of age with either cells or vehicle. When 18 weeks old, the mice were examined sequentially in a series of tests spanning behavior to anatomy. The arrows indicate the sequence of tests, and italics indicate the relevant figures.

(B) Sham-injected (top) and hGPC-transplanted (bottom) shiverers were videoed from below on a treadmill by using DigiGait.

(C) Of the 8 shiverer controls and 8 transplanted shiverers tested on the treadmill, only 2 of 8 untreated mice were able to walk on the treadmill, whereas 7 of 8 engrafted mice did so on their first try (p = 0.012, chi-square; see Video S1), and all 8 did so on a second attempt.

(D) Schematic of the measurements taken to assess the trans-callosal response to electrical stimulation of sampled slices.

(E) Representative traces of normally myelinated shiverer heterozygous mice (WT), sham-injected shiverers (sham), and transplanted shiverers (Tpts), demonstrating restoration of the fast conduction N1 component in the transplanted mice.

(F) N1 amplitude shows no significant difference between slice preparations derived from normal WT and transplanted shiverer (Tpt) brains, suggesting transplant-mediated normalization of the ratio of myelinated to unmyelinated axons in the engrafted shiverer brain. Untreated shiverers have effective N1 velocities of zero and cannot be assessed as such.

(G) The slow N2 component conduction velocity of transplanted shiverer callosal slices was significantly more rapid than that of untreated shiverers and no different from that of WTs.

(H–P) All images were taken from 18-week-old shiverermice mice injected intracallosally at 4 weeks with hGPCs. (H) Low-magnification image of the corpus callosum (CC) of one hemisphere of an adult-engrafted shiverer. MBP, green. (I) Human oligodendrocytes, co-immunostained for human cytoplasmic antigen (hCyto) and MBP; the latter is necessarily human, as shiverer does not make MBP. (J) A single mature donor-derived oligodendrocyte. Right-hand images show respective color splits for human cytoplasm (red) and MBP (green), showing the many myelinating sheaths produced by a single hGPC-derived oligodendrocyte. (K–L) Electron micrographs of a sham-control CC demonstrating the thin myelin sheaths characteristic of shiverer. (M–P) Electron microscopy images of transplanted shiverers. (M–O) The variety of donor cell-ensheathed host axons, and the insets show higher power images of the major dense lines (arrowheads), characteristic of compact myelin. (P) Higher power image of the detailed myelin ultrastrure of a donor cell-myelinated axon.

Scale bars: 100 μm (H), 20 μm (I–J), 500 nm (K and L), 200 nm (M–P), and 100 nm (M’–P’).