The immunosuppressive substance 2-chloro-2-deoxyadenosine modulates lipoprotein metabolism in a murine macrophage cell line (P388 cells).
A recently developed immunosuppressive substance, 2-chloro-2-deoxyadenosine (2-CdA), was reported to inhibit monocyte functions at low concentration. Because macrophages play a key role in the formation of atherosclerotic plaques, it was of interest to study the effect of 2-CdA on cellular lipid metabolism. For this purpose we have used a macrophage cell line (P388) to perform incubation studies in the presence of acetylated low density lipoprotein (Ac-LDL) and 2-CdA. The addition of 2-CdA, in concentrations ranging from 5-20 nM, induced a dose-dependent decrease in cellular cholesterol content and in the amount of extracellular [14C]oleic acid (OA) incorporated into the cholesteryl ester (CE) fraction. The effect was maximized at 20 nM 2-CdA with an 86% reduction in cholesterol esterification compared to controls (P < 0.008). To evaluate the mechanism of interaction of 2-CdA with cellular lipid metabolism, deoxycytidine (dCyt) and 3-methoxybenzamide (3-MOB), substances known to antagonize the effect of 2-CdA in different ways, were co-administered with 2-CdA. dCyt, a competitive inhibitor of dCyt kinase, which catalyzes phosphorylation to the active metabolite, antagonized the effects of 20 nM 2-CdA, producing significantly greater incorporation of extracellular [14C]OA into the CE fraction than in the presence of 2-CdA alone (P < 0.0086). Co-incubation with 2-CdA and the poly-ADP-ribose synthetase inhibitor 3-MOB, which is known to render cells resistant to 2-CdA toxicity by preventing cellular nicotinamide adenine dinucleotide (NAD)- and adenosine triphosphase-depletion, also reversed the effect of 2-CdA on lipid accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)
Lechleitner
M
M
Department of Internal Medicine, University of Innsbruck, Austria.
Auer
B
B
Zilian
U
U
Hoppichler
F
F
Schirmer
M
M
Föger
B
B
Geisen
F
F
Patsch
J R
JR
Konwalinka
G
G
D000107:Acetylation; D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D017338:Cladribine / Q000494:pharmacology*; D003842:Deoxycytidine Kinase / Q000378:metabolism; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D007941:Leukemia P388 / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D009243:NAD / Q000378:metabolism; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D001549:Benzamides; D002788:Cholesterol Esters; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D009829:Oleic Acids; D014280:Triglycerides; D009243:NAD; D000628:Aminophylline; D019301:Oleic Acid; D017338:Cladribine; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D003842:Deoxycytidine Kinase; C025159:3-methoxybenzamide