GPR17 and periventricular leukomalacia: As shown in Figure 4b-c, compared to the sham group, GPR17 was upregulated while Olig1 was downregulated in the PVL group, which were further aggravated in the GPR17-overexpressed group and reversed in the siR-GPR17 group (**p < 0.01 vs. sham, #p < 0.05, vs. PVL, ##p < 0.01 vs. PVL).