The vascular geneApold1is dispensable for normal development but controls angiogenesis under pathological conditions

Abstract

AbstractThe molecular mechanisms of angiogenesis have been intensely studied, but many genes that control endothelial behavior and fate still need to be described. Here, we characterize the role ofApold1(Apolipoprotein L domain containing 1) in angiogenesisin vivoandin vitro. Single-cell analyses reveal that - across tissues - the expression ofApold1is restricted to the vasculature, and thatApold1expression in endothelial cells (ECs) is highly sensitive to environmental factors. UsingApold1-/-mice, we find thatApold1is dispensable for development and does not affect postnatal retinal angiogenesis nor alters the vascular network in adult brain and muscle. However, when exposed to ischemic conditions following photothrombotic stroke as well as femoral artery ligation,Apold1-/-micedisplay dramatic impairments in recovery and revascularization. We also find that human tumor endothelial cells express strikingly higher levels ofApold1,and thatApold1deletion in mice stunts the growth of subcutaneous B16 melanoma tumors, which have smaller and poorly perfused vessels. Mechanistically,Apold1is activated in ECs upon growth factor stimulation as well as in hypoxia, andApold1intrinsically controls EC proliferation but not migration. Our data demonstrate thatApold1is a key regulator of angiogenesis in pathological settings, whereas it does not affect developmental angiogenesis, thus making it a promising candidate for clinical investigation.