Moreover, retinal ganglion cells (RGCs) also control retinal vessel growth through G protein-coupled receptor-91 (GPR91) (Sapieha et al., 2008) and neuronal guidance cue semaphorin 3 A (SEMA3A) (Joyal et al., 2011), and capillary degeneration in mice induced with ischemia-reperfusion injury (Ueda et al., 2010; Zheng et al., 2007). The gene discussed is SEMA3A; the disease is ischemia reperfusion injury.