EFFECTS OF TUMOR-NECROSIS-FACTOR ON RECEPTOR-MEDIATED ENDOCYTOSIS ANDBARRIER FUNCTIONS OF BOVINE BRAIN CAPILLARY ENDOTHELIAL-CELL MONOLAYERS

Tumor necrosis factor alpha (TNF-alpha) plays a crucial role in the pa thogenesis of the central nervous system infections. In an in vitro re constructed blood-brain barrier model, a significant dysregulation of receptor mediated endocytosis of low density lipoproteins (LDL) and tr ansfenin (Tf) is demonstrated at delayed phase of direct TNF-alpha act ivation. Concomitant with the increase in LDL uptake, we demonstrate a decrease of Tf-receptor mediated endocytosis. The potential role of T NF action in the differential or opposite routing of macromolecules is also characterized by a stimulation of their transcytosis. These find ings may provide a new insight into the inflammatory effect of TNF-alp ha on brain capillary endothelial cells.