ADAM17 overexpression promotes angiogenesis by increasing blood vessel sprouting and pericyte number during brain microvessel development

The angiogenic process is precisely regulated by different molecular mechanisms, with a balance between stimulatory and inhibitory factors in embryonic development. Transmembrane proteins of the ADAM (a disintegrin and metalloprotease) family play a critical role in embryogenesis and are involved in protein ectodomain shedding, as well as cell-cell and cell-matrix interactions. In the present study, we found that ADAM17 is expressed spatiotemporally in the tectal layers during chicken embryonic development. To investigate the effect of ADAM17 overexpression on angiogenesis, chicken ADAM17 plasmids were transfected into the developing tectum in vivo by electroporation. Results showed that overexpression of ADAM17 induces morphological changes of brain microvessels, such as an increase in diameter, of capillary sprouting from radial microvessels and an increase in the number of pericytes, but not of endothelial cells. Our data suggest that overexpression of ADAM17 in the developing tectum promotes angiogenesis by increasing the number of pericytes and capillary sprouting in the radial vessels.