Brain-specific differentiation of mouse yolk sac endothelial cells

Vascular endothelial cells exhibit diverse functional and biochemical prope rties that vary among tissues and organs, suggesting that differentiation o f endothelial cells is influenced by their microenvironment. In this study, relatively undifferentiated endothelial cells from 9-day embryonic mouse y olk sac were co-cultured with 12-day embryonic mouse brain rudiments. Organ -specific differentiation of the yolk sac endothelial cells was monitored b ased on the expression and functional activities of two brain-specific endo thelial cell markers, glucose transporter 1 (Glut-1) and P-glycoprotein. Im munochemical staining, semi-quantitative reverse transcription-polymerase c hain reaction (RT-PCR) and functional assays demonstrated that yolk sac end othelial cells can acquire brain-specific properties after induction by bra in rudiments. This result provides support for the hypothesis that endothel ial cell heterogeneity is acquired during organogenesis. (C) 1999 Elsevier Science B.V. All rights reserved.