Figure 2. OPC-specific Pten ablation enhances oligodendrocyte differentiation and OPC proliferation in the brain.

(A) Experimental scheme for 4HT injection and BrdU administration into Pdgfra-CreER; R26-EYFP; ±Pten^f/f mice, and for mouse sampling. For P45 +30, 4HT (1 mg per injection) was injected five times between P45 and P47 (a total of 5 mg). (B) Confocal images of phosphorylated S6 ribosomal protein (pS6) and EYFP⁺ cells in the CC at P20 +21. Arrowheads and asterisks indicate EYFP⁺ pS6⁺ cells and EYFP⁺pS6^- cells, respectively. Scale bar, 50 µm. (C) Percentage of pS6⁺ cells among EYFP-labeled cells in the CC at P20 +21. n = 5 mice per group. (D) Fluorescence (left) and confocal (right) images of EYFP⁺ cells in the brains of the 4HT-administered control and Pten cKO mice (P20 +21). The confocal images were taken from the CTX. Arrowheads indicate EYFP⁺CC1⁺ mature OLs. Scale bars, 500 μm (left) and 50 μm (right). (E) Number of total EYFP⁺ cells was increased in the CTX of Pten cKO mice during the OPC fate analysis for the two age windows. (F) Number of EYFP⁺CC1⁺ OLs. (G) The numbers of EYFP⁺NG2⁺ OPCs were not changed by the Pten cKO. (H) Percentages of OPC, pre-OL and OL among EYFP-labeled cells. (I) Fluorescence (left) and confocal (right) images of BrdU⁺ cells in the CTX (P20 +21). Arrowheads indicate BrdU⁺NG2⁺ OPCs. Scale bars, 500 μm (left) or 50 μm (right). (J) Quantification of BrdU⁺NG2⁺ OPCs in the CC and CTX. (K) Confocal images showing disruption of tiled OPC distribution in the CTX of Pten cKO mice (P20 +21). An arrow indicates a cortical area devoid of an NG2⁺ OPC. Scale bar, 50 μm. (L) Number of total OPCs. Data are represented as mean ±S.E.M. n = 4 ~ 7 mice per group for P20 ~41. n = 3 ~ 5 mice per group for P45 ~P75. *p<0.05; **p<0.01; ***p<0.001. Unpaired Student's t-test. The numerical data for the graphs are available in Figure 2—source data 1.

Figure 2—figure supplement 1. OPC-specific Pten ablation enhances oligodendrocyte differentiation in the spinal cord.

(A) Fluorescence (left) and confocal (right) images of SC EYFP⁺ cells in Pdgfra-CreER; R26-EYFP; ±Pten^f/f mice (P20 +21). The identity of EYFP⁺ cells in the boxed areas (left) was determined by co-immunostaining with maturation stage markers (right). Arrowheads indicate newly generated EYFP⁺CC1⁺ OLs. Scale bars, 100 µm (left) and 50 µm (right). (B - E) Quantification of EYFP⁺ cells (B), EYFP⁺CC1⁺ new OLs (C), EYFP⁺NG2⁺ OPCs (D) and total NG2⁺ OPCs (E) in the SC of control and Pten cKO mice. Data are represented as mean ±S.E.M. n = 3 ~ 6 (control), or 3 ~ 5 (Pten cKO) mice. *p<0.05; **p<0.01; ***p<0.001. Unpaired Student's t-test. The numerical data for the graphs are available in Figure 2—figure supplement 1—source data 1.