Endocytosis of horseradish peroxidase by brain microvascular and umbilical vein endothelial cells in culture: an ultrastructural and morphometric study.
The ability to form tight junctions and the paucity of fluid phase endocytosis showed by brain microvacular endothelial cells (BMECs) make up the structural basis of the blood-brain barrier (BBB). Most studies on cultured BMECs focused on intercellular junctions, whereas endocytosis received lesser attention. We studied endocytosis of horseradish peroxidase in primary and passage 1 and 2 BMEC cultures from rat brain as well as in human umbilical vein endothelial cell (HUVEC) culture. Endocytic activity was also analyzed in passage 1 BMECs treated with lipopolysaccharide (LPS, 1 microg/ml for 4 h), which mimics BBB disruption in bacterial meningoencephalitis. The percent of cytoplasmic area occupied by endocytic profiles (vesicles <70 nm and vacuoles >70 nm) and their mean number per cell were significantly lower in primary and passaged BMEC than in HUVEC cultures. The area and number of endocytic profiles significantly increased in BMECs after exposure to LPS. BMECs cultured under standard conditions may be a suitable model for studying the mechanism of increased fluid phase endocytosis in certain diseases and injury states.
Defazio
G
G
Institute of Neurology, University of Bari, Italy.
Ribatti
D
D
Nico
B
B
Ricchiuti
F
F
De Salvia
R
R
Roncali
L
L
Livrea
P
P
D000818:Animals; D002196:Capillaries / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002478:Cells, Cultured; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure; D004731:Endotoxins / Q000494:pharmacology; D006735:Horseradish Peroxidase; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014471:Umbilical Veins / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D004731:Endotoxins; D008070:Lipopolysaccharides; C044101:endotoxin, Escherichia coli; D006735:Horseradish Peroxidase