CircPDE4B was downregulated in ROP models with reduced capability of sponging miR-181c; hence, it suppressed the expression of the tumor suppressor protein von Hippel-Lindau (VHL) in hypoxia-induced human retinal ECs and subsequently activated the expression of HIF-1α and VEGFA and HIF-1α-dependent angiogenesis [74,76]. The gene discussed is HIF1A; the disease is retinopathy of prematurity.