Redox regulation of 7-ketocholesterol-induced apoptosis by beta-carotene in human macrophages.
The aim of this study was to verify the hypothesis that beta-carotene may prevent 7-ketocholesterol (7-KC)-induced apoptosis in human macrophages. Therefore, THP-1 macrophages were exposed to 7-KC (5-50 microM) alone and in combination with beta-carotene (0.25-1 microM). 7-KC inhibited the growth of macrophages in a dose- and a time-dependent manner by inducing an arrest of cell cycle progression in the G0/G1 phase and apoptosis. Concomitantly, p53, p21, and Bax expressions were increased by 7-KC, whereas the levels of AKT, Bcl-2, and Bcl-xL were decreased. beta-Carotene prevented the growth-inhibitory effects of 7-KC in a dose- and time-dependent manner as well as the effects of 7-KC on the expression of cell cycle- and apoptosis-related proteins. 7-KC also enhanced reactive oxygen species (ROS) production through an increased expression of NAD(P)H oxidase (NOX-4). The effects of 7-KC were counteracted by the addition of the NAD(P)H oxidase inhibitor DPI or by cotransfection of siNOX-4 mRNA. beta-Carotene prevented 7-KC-induced increase in ROS production and in NOX-4 expression, as well as the phosphorylation of p38, JNK, and ERK1/2 induced by 7-KC. These data suggest a possible antiatherogenic role of beta-carotene through the prevention of 7-KC toxicity in human macrophages.
Palozza
Paola
P
Institute of General Pathology, Catholic University School of Medicine, L. Go F. Vito, 1 00168 Rome, Italy. p.palozza@rm.unicatt.it
Serini
Simona
S
Verdecchia
Sara
S
Ameruso
Maria
M
Trombino
Sonia
S
Picci
Nevio
N
Monego
Giovanni
G
Ranelletti
Franco O
FO
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D007653:Ketocholesterols / Q000037:antagonists & inhibitors* / Q000633:toxicity; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D024502:alpha-Tocopherol / Q000494:pharmacology; D019207:beta Carotene / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins; D007653:Ketocholesterols; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D019207:beta Carotene; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D024502:alpha-Tocopherol; C003001:7-ketocholesterol