(A), (B) Percentage of MBP+ oligodendrocytes generated from OPCs following treatment with bioactive small molecules at 2 μM (A) and 6 μM (B). n=4 wells per condition, except DMSO and amorolfine, a known sterol 14-reductase inhibitor, n=8 wells, with >1,000 cells analyzed per well. (C), (D) GC-MS based quantification of 14-dehydrozymostenol, zymostenol, and zymosterol levels in OPCs treated for 24 h with TASIN-1 (1 μM), a known EBP inhibitor, and the indicated screening hits at the concentrations shown in panel (A) and (B). n=2 wells per condition. € Representative images of OPCs treated with amorolfine at 600 nM, toremifene citrate at 2 μM, and fenspiride HCl at 6 μM. Nuclei are labeled with DAPI (blue), and oligodendrocytes are shown by immunostaining for MBP (green). Scale bar, 100 μm. For percentage of MBP+ oligodendrocytes for all bioactive small molecules that were screened, see Fig. S2. S14R, sterol 14-reductase.