26-hydroxycholesterol-stimulated DNA synthesis in smooth muscle cells and induction of endothelial injury using a coculture technique.
We investigated the effects of 0.5, 2.5, and 10 micrograms/ml of cholesterol or 26-hydroxycholesterol on bovine aortic ECs and SMCs. Suppression of viable cell density and cytotoxic changes in both cells were induced by 2.5 and 10 micrograms/ml 26-hydroxycholesterol. ECs were more severely damaged than SMCs in the presence of 26-hydroxycholesterol. Levels of up to 10 micrograms/ml cholesterol had no effect on ECs or SMCs growth or cytotoxicity. Confluent ECs exposed to 2.5 or 10 micrograms/ml of 26-hydroxycholesterol secreted significant amounts of 6-ketoprostaglandin F1 alpha after a 24-hr incubation. An equivalent concentration of cholesterol had no such effect. SMCs cocultured with ECs exposed to 10 micrograms/ml 26-hydroxycholesterol, when compared with an equivalent level of cholesterol, synthesized DNA in significantly greater amounts during a 24-hr incubation. The cocultured ECs incubated in the presence of 2.5 and 10 micrograms/ml 26-hydroxycholesterol were partially detached due to cell death. However, no difference was observed in the DNA content of SMCs cultured without ECs in the presence of cholesterol or 26-hydroxycholesterol. The results suggest that 26-hydroxycholesterol produced not only cytotoxicity to ECs and SMCs but also stimulated DNA synthesis in SMCs through endothelial injury.
Jimi
S
S
Department of Food Science, University of Illinois, Urbana 61801.
Smith
T L
TL
Kummerow
F
F
D000818:Animals; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002784:Cholesterol / Q000633:toxicity; D004247:DNA / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D011464:Epoprostenol / Q000378:metabolism; D006888:Hydroxycholesterols / Q000633:toxicity*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000648:ultrastructure
D006888:Hydroxycholesterols; C007042:cholest-5-ene-3 beta,26-diol; D004247:DNA; D002784:Cholesterol; D011464:Epoprostenol