Summary
Vascular endothelial growth factor (VEGF) is essential for the differentiation of
the primitive embryonic vascular system and has been implicated in the vascularization
of organs. Recently, VEGF has also been proposed to play a role in neural development,
neuroprotection, and adult neurogenesis. Here we have investigated the function of
VEGF in the developing brain by cre-lox technology. We show that VEGF produced by
the embryonic neuroectoderm is required for the vascularization and the development
of the brain. Both the invasion and the directed growth of capillaries were severely
impaired in the fore-, midand hindbrain of VEGFlox/lox/nestin-cre mouse embryos homozygous for a VEGF mutation in the neural tube. These observations
demonstrate thatVEGF, via local secretion by neural progenitors, induces brain angiogenesis
and guides the growth of capillaries toward the ventricular zone. VEGF deficiency
led to developmental retardation and progressive destruction of neural tissue in all
brain regions.The defect was most pronounced in telencephalic structures, such as
the hippocampus, and caused microcephaly.Taken together, the findings establish the
critical importance of neuroectoderm-derived VEGF in the morphogenesis of the brain.
VEGF acts as a key regulator of brain angiogenesis and provides instructive cues for
the correct spatial organization of the vasculature.
Keywords
Angiogenesis - brain development - microcephaly - retina - VEGF