Figure 9. OPC-specific Gsk3b ablation enhances oligodendrocyte differentiation in the brain.

(A) Experimental scheme for tamoxifen and BrdU administration into Pdgfra-CreER; R26-EYFP; ±Gsk3b^f/f and for mouse sampling. Tamoxifen (40 mg/kg per i.p. injection) was injected five times for 2.5 days starting P20. (B) Validation of Gsk3b deletion. EYFP⁺ cells were isolated from the CTX of Pdgfra-CreER; R26-EYFP; ±Gsk3b^f/f mice by FACS at P20 +8. The isolated EYFP-labeled cells were subjected to RT-qPCR for Gsk3b mRNA levels. n = 3 (control) and 4 (Gsk3b cKO) mice. (C) Quantification of BrdU⁺ cells in the CTX at P20 +21. There was an increases in BrdU⁺NG2⁺ OPCs in the Gsk3b cKO mice (P20 +21). n = 5 mice per group. (D) Confocal images of EYFP⁺CC1⁺ OLs (arrowheads) in the CC and CTX. Scale bar, 50 μm. (E - H) Quantification of total EYFP⁺ cells (E), EYFP⁺CC1⁺ OLs (F), EYFP⁺NG2⁺ OPCs (G), and total NG2⁺ OPCs (H). (I) Percentages of OPC, pre-OL and OL among EYFP-labeled cells. n = 8 (control) or 6 (Gsk3b cKO) mice for (E – I). (J) Representative EM of callosal axons (P13 +17). R26-EYFP (control) or Pdgfra-CreER; R26-EYFP; Gsk3b^f/f (Gsk3b cKO) mice were used. Scale bar, 500 nm. (K) Scatter plot of the g-ratios. (L) Average of g-ratio. At least 130 axons per mouse, three mice per group were analyzed. (M) Percentage of myelinated axons. Data are represented as mean ±S.E.M. n = 3 mice per group (K – M). *p<0.05; **p<0.01; ***p<0.001. Unpaired Student's t-test. The numerical data for the graphs are available in Figure 9—source data 1.

Figure 9—figure supplement 1. OL-specific Gsk3b ablation does not change the number of oligodendrocyte, but enhances expression levels of MBP and CNP.

(A) Quantification of CC1⁺ OLs in the CTX of the control (Mog-iCre; R26-EYFP) and OL-specific Gsk3b cKO (Mog-iCre; R26-EYFP; Gsk3b^f/f) mice at P31. (B) Quantification of NG2⁺ OPCs. n = 3 mice per group for (A, B). (C, D) Western blot analysis of cortical lysates for myelin proteins, MAG, MBP, and CNP. Cortices were isolated from Gsk3b^f/f (control) and Mog-iCre; Gsk3b^f/f (Gsk3b cKO) mice (P31). n = 4 mice per group for (C, D). Data are represented as mean ±S.E.M. *p<0.05, **p<0.01. Unpaired Student's t-test. The numerical data for the graphs are available in Figure 9—figure supplement 1—source data 1. Original western images are available in Figure 9—figure supplement 1—source data 2. List of source data files.