Proapoptotic nitric oxide production in amyloid beta protein-treated cerebral microvascular endothelial cells.
OBJECTIVE
The objective of this study was to investigate the effects of amyloid beta protein (Abeta) on cerebral microvascular endothelium, and their possible involvement in Abeta-induced apoptosis in the neighboring cells.


METHODS
Cultured bovine brain microvascular endothelial cells (BBECs) were incubated with Abeta for 24 h. Production of nitric oxide (NO) was assessed by nitric oxide-sensitive fluorescent dye, DAF-2, and the expression of NO synthase (NOS) proteins was examined by Western blotting. Effects of Abeta-treated microvascular endothelium on the DNA damage of the neighboring cells were assessed by single-cell gel electrophoresis.


RESULTS
Abeta increased the expression of iNOS protein, but did not affect eNOS and nNOS expressions in BBECs. Abeta-treated BBECs showed spontaneous NO production in the presence of L-arginine. The neural cell line PC12 showed marked apoptosis after being co-cultured with Abeta-treated BBECs for 48 h, and the apoptosis was as potent as that induced by the inflammatory stimuli lipopolysaccharide and interferon-gamma. The DNA damage of PC12 cells evoked by co-culture with Abeta-treated BBECs was prevented by L-NG-nitroarginine methyl ester, an inhibitor of NOS.


CONCLUSIONS
These results indicate that Abeta induces the expression of iNOS in BBECs, and that microvascular endothelium-derived NO may induce apoptosis in neighboring neural cells.
Kimura
Chiwaka
C
Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Oike
Masahiro
M
Watanabe
Michi
M
Ito
Yushi
Y
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002417:Cattle; D002560:Cerebrovascular Circulation; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats
D016229:Amyloid beta-Peptides; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D007371:Interferon-gamma; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III