Brain-specific differentiation of mouse yolk sac endothelial cells

Vascular endothelial cells exhibit diverse functional and biochemical properties that vary among tissues and organs, suggesting that differentiation of endothelial cells is influenced by their microenvironment. In this study, relatively undifferentiated endothelial cells from 9-day embryonic mouse yolk sac were co-cultured with 12-day embryonic mouse brain rudiments. Organ-specific differentiation of the yolk sac endothelial cells was monitored based on the expression and functional activities of two brain-specific endothelial cell markers, glucose transporter 1 (Glut-1) and P-glycoprotein. Immunochemical staining, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and functional assays demonstrated that yolk sac endothelial cells can acquire brain-specific properties after induction by brain rudiments. This result provides support for the hypothesis that endothelial cell heterogeneity is acquired during organogenesis.