Vasohibin Inhibits Large Blood Vessel Formation and Supports Development of Microvessels

Aims: The murine homolog of human vasohibin (mVASH1), a putative antiangiogenic protein, was investigated for its inhibitory effects on in vitro and in vivo angiogenesis. Cell growth and migration was analyzed in murine embryonic fibroblasts, smooth muscle cells and brain endothelial cells (bEND.3). Moreover, angiogenic sprouting was studied on human umbilical vein endothelial cells (HUVEC) in the spheroid sprouting assay. In vivo effects on blood vessel formation were investigated in the chorioallontoic membrane assay and in the murine B16F10 melanoma model.

Results: Purified mVASH1 protein inhibited cell growth and migration of murine endothelial cell and fibroblasts, but not of vascular aortic smooth muscle cells (AoSMC). Adenovial overexpression did not inhibit proliferation or VEGF/bFGF induced capillary sprouting of HUVEC in the spheroid assay. Murine VASH1 inhibited growth of large vessels in the chorioallantoic membrane assay and induced the formation of a dense, fine capillary network. Subcutaneous growth of VASH1 overexpressing B16F10 melanomas in C57BL/6 mice was not affected within the observed time frame, but there was a significant increase of microvessels and coverage of blood vessels with alpha-smooth muscle cell actin positive mural cells.

Conclusions: Our data implicate that the murine VASH1 causes angiogenic remodelling by inhibiting the growth of large vessels in vivo and by supporting the formation of microvessels and their coverage with smooth muscle cells. EG and GU contributed equally to this work.