Figure 3. hGPCs Differentiate and Remyelinate Axons after Transplant into Adult-Demyelinated Brain.
(A) At 6 weeks of age, experimental mice were put on a diet containing 0.2% cuprizone, whereas littermate controls remained on a standard diet. At 10 weeks, 4 weeks into a 20-week cuprizone course, the mice were transplanted with 2 × 105 hGPCs. Mice were sacrificed for histology either at the end of the cuprizone course (at 26 weeks) or after an additional 20-week recovery period (at 46 weeks).
(B and C) Maps show locations of individual human cells in 20-μm coronal hemi-sections of engrafted brains. (B) Transplantation of hGPCs into a normally myelinated 10-week-old mouse yielded widespread engraftment, when mapped 36 weeks later at 46 weeks of age. (C) In cuprizone-treated mice, transplanted hGPCs expanded to a significantly greater degree.
(D–H) Significantly more hGPCs differentiated as TF-defined oligodendrocytes in the cuprizone-demyelinated brains than in their untreated controls. (D) hGPCs were more likely to differentiate as TF-expressing oligodendrocytes when transplanted into a demyelinating environment (left) than into a control brain (right). (E and F) The absolute density of human cells (E) and relative proportion that differentiated as TF+ oligodendrocytes (F) in the corpus callosum were >5- and >10-fold greater, respectively, in mice on the cuprizone diet than in their untreated controls. (G) By 36 weeks post-transplant, over a quarter of all oligodendrocytes in the host white matter were of human origin. (H) The overall density of TF-defined oligodendrocytes, whether of mouse or human origin, was relatively preserved at all time points. (E–G) *p < 0.05; **p < 0.01; ***p < 0.001.
(I–K) By 46 weeks, adult-transplanted hGPCs are admixed with murine cells in the largely remyelinated corpus callosum (I). (J) By this point, most myelinating oligodendrocytes in the cuprizone-demyelinated callosal were of human donor origin (human nuclear antigen, red; MBP, green; DAPI, blue), and just as many of the resident human cells had differentiated as TF-defined oligodendrocytes (K) (human nuclear antigen, red; TF, green).
Scale bars: 100 μm (I), 10 μm (J), and 50 μm (K).