HEY1 and isolated hemihyperplasia: In an IH mouse model, blocking Jagged1 inhibited angiogenesis.[14]HEY1 is an important downstream target gene of the Notch pathway, and Hey1 is expressed in the endothelial cells of hemangioma.[15] Further, knockout of the effector genes Hesr1/Hey1 and Hesr2/Hey2 of the Notch pathway caused severe vascular defects and bleeding in mouse embryos, and death before maturation.[16] In the present study, propranolol intervention inhibited HUVEC proliferation and increased Jagged1 expression in a time-dependent manner.