Endothelial cell-astrocyte interactions and TGF beta are required for induction of blood-neural barrier properties.
We sought to establish a blood-neural barrier (BNB) model of astrocyte contact with endothelial cells (EC) to test the hypothesis that transforming growth factor beta (TGF beta) promotes an EC barrier-phenotype. Astrocyte-EC contact induced BNB properties in EC. Transendothelial resistance was augmented by direct contact between astrocytes-EC, but not by astrocyte-conditioned medium or astrocyte-EC coculture conditioned medium. Coculture of EC and astrocytes led to significant increase in endothelial occludin levels and junctional localization. EC gamma-glutamyl-transferase (GGT) activity was increased by direct contact with astrocytes, by conditioned medium from cocultures or by TGF beta1. Coculture inhibited EC proliferation with no effect on astrocyte proliferation. A neutralizing antibody to TGF beta decreased GGT activity in cocultures and increased cell number. Whereas total TGF beta was not significantly altered by coculture, activated TGF beta increased in astrocyte-EC cocultures. In summary, astrocyte-EC contact induces BNB characteristics in EC and locally activated TGF beta is responsible for part of the induction.
Garcia
Claudia M
CM
Biological and Biomedical Sciences Graduate Program, Harvard Medical School, Boston, MA, USA.
Darland
Diane C
DC
Massingham
Lauren J
LJ
D'Amore
Patricia A
PA
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000378:metabolism*; D015153:Blotting, Western; D002450:Cell Communication / Q000502:physiology*; D002455:Cell Division; D002478:Cells, Cultured; D018920:Coculture Techniques; D017097:Electric Impedance; D042783:Endothelial Cells / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D062793:Occludin; D019108:Tight Junctions / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D005723:gamma-Glutamyltransferase / Q000378:metabolism
D008565:Membrane Proteins; D062793:Occludin; D016212:Transforming Growth Factor beta; D005723:gamma-Glutamyltransferase