Astrocytes secrete a factor inducing the expression of HT7-protein and neurothelin in endothelial cells of chorioallantoic vessels.
Among the most specific markers of the blood-brain barrier phenotype of endothelial cells are the well-characterized immunoglobulin-like surface glycoprotein HT7 and the probably related or identical glycoprotein neurothelin. Both can be induced in chorioallantoic vessels by transplants of embryonic mouse brain. Other blood-brain barrier markers have been shown to be inducible by type-1 astrocytes in endothelial cells of non-neural origin. In the present work we tested the hypothesis that this cellular interaction between astrocytes and endothelial cells is mediated by a soluble factor(s). Chorioallantoic vessels of embryonic day 9 chick embryos were exposed for 4 or 10 days to a constant and localized delivery of astrocyte-conditioned medium by using a piece of gelfoam posed onto the chorioallantoic membrane, as a localized reservoir, which was connected to a miniosmotic pump system delivering astrocyte-conditioned medium at a steady rate. We found that in a significant number of chorioallantoic vessels located near the gelfoam, endothelial cells exposed to astrocyte-conditioned medium for a period of 4 or 10 days, but not to glioma-, fibroblast- or endothelial cell-derived conditioned medium, expressed the HT7 antigen and neurothelin. These results provide evidence that type-1-astrocytes are capable of inducing blood-brain barrier related properties in endothelial cells of non-neural origin through a soluble factor(s).
Janzer
R C
RC
Institute of Pathology, University of Lausanne, Switzerland.
Lobrinus
J A
JA
Darekar
P
P
Juillerat
L
L
D000482:Allantois / Q000098:blood supply; D000818:Animals; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D001253:Astrocytes / Q000378:metabolism*; D030161:Avian Proteins; D051926:Basigin; D001685:Biological Factors / Q000378:metabolism / Q000502:physiology*; D001798:Blood Proteins; D001812:Blood-Brain Barrier / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D002823:Chorion / Q000098:blood supply; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D012995:Solubility
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D001685:Biological Factors; D001798:Blood Proteins; C102624:Bsg protein, Gallus gallus; C079432:Bsg protein, rat; D008562:Membrane Glycoproteins; D051926:Basigin