Acyl-coenzymeA (CoA):cholesterol acyltransferase inhibition in rat and human aortic smooth muscle cells is nontoxic and retards foam cell formation.
OBJECTIVE
Studies in vitro and in vivo of macrophage foam cells have shown evidence of cytotoxicity after acyl-CoA:cholesterol acyltransferase (ACAT) inhibition. Foam cells of smooth muscle origin are also found in human and animal atherosclerotic lesions.


RESULTS
To study whether cytotoxicity from ACAT inhibition is independent of cell type, we first established a protocol to conveniently induce aortic smooth muscle foam cell formation using cholesterol-cyclodextrin complexes (CCC). Rat aortic smooth muscle cells (ASMCs) treated for 48 hours with CCC (20 microg/mL) became foam cells by morphological (oil-red-O staining) and biochemical (approximately 1200% and approximately 180% increase in cellular esterified and free cholesterol, respectively) criteria. ACAT activity increased 500% (P<0.01 versus untreated). Similar results were obtained in human ASMC, but ACAT activity increased to an even greater extent (3200%; P<0.01 versus untreated). Western blots indicated that CCC treatment increased human (to 380+/-20% of untreated, P<0.001), but not rat, ACAT protein expression. ACAT inhibition by Fujirebio compound F1394 suppressed CCC-induced foam cell formation in rat and human ASMC, but, notably, did not induce significant cytotoxicity.


CONCLUSIONS
ASMC might be more resistant to FC-induced adverse effects than are macrophages.
Rong
James X
JX
Marc and Ruti Bell Vascular Biology Research Program of the Leon H. Charney Division of Cardiology, Department of Medicine, New York, NY 10016, USA.
Kusunoki
Jun
J
Oelkers
Peter
P
Sturley
Stephen L
SL
Fisher
Edward A
EA
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000201:enzymology*; D002457:Cell Extracts / Q000737:chemistry; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism / Q000494:pharmacology; D003505:Cyclodextrins / Q000378:metabolism / Q000494:pharmacology; D003510:Cyclohexanes / Q000494:pharmacology / Q000633:toxicity*; D004146:Dioxanes / Q000494:pharmacology / Q000633:toxicity*; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000633:toxicity; D005487:Foam Cells / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D008970:Molecular Weight; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology; D032389:Myocytes, Smooth Muscle / Q000201:enzymology*; D051381:Rats; D002785:Sterol O-Acyltransferase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism / Q000502:physiology
D002457:Cell Extracts; D003505:Cyclodextrins; D003510:Cyclohexanes; D004146:Dioxanes; D004791:Enzyme Inhibitors; C094918:F 1394; D002784:Cholesterol; D002785:Sterol O-Acyltransferase; C493492:sterol O-acyltransferase 1