Olig2

OPCs were plated on 8‐well Permanox chamber‐slides (Nunc, Naperville, IL), precoated with 5 µg/mL PLL followed by appropriate aFn or pFn coatings (described above), at a density of 30,000 cells per well. OPCs were allowed to incorporate 5‐bromo‐2‐deoxyuridine (BrdU; 10 µM; Roche) for 24 h in the presence of 10 ng/mL PDGF‐AA and 10 ng/mL FGF‐2. Then, cells were fixed in 4% PFA for 20 min, and additionally fixed in 5% acetic acid in ethanol for 20 min. BrdU was detected using reagents from the BrdU labeling and Detection Kit I (Roche) according to the manufacturer's instructions with the addition of the oligodendrocyte lineage marker Olig2 (Abcam) and Alexa Fluor© 546‐conjugated anti‐rabbit antibody, and visualization of nuclei with DAPI (1 µg/mL). To compare the percentages of BrdU‐incorporating cells between the conditions, the numbers of double BrdU‐ and Olig2‐positive cells were counted relative to the Olig2‐positive cells (at least 150 cells per condition) from images captured with a Leica TCS SP8 Confocal Laser Scanning Microscope.