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KMID : 0603820140200040237
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Journal of Experimental & Biomedical Science
2014 Volume.20 No. 4 p.237 ~ p.243
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Triglyceride Up-regulates Expression of ABCG1 in PMA-induced THP-1 Macrophages Through Activation of JNK and p38 MAPK Pathways
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Lim Jae-Won
Kim Sung-Hoon
Kang Yeo-Wool
Jung Byung-Chul
Kim Hyun-Kyung
Lee Ju-Yeon
Lee Dong-Sup
Rhee Ki-Jong
Kim Yoon-Suk
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Abstract
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Triglyceride (TG) can cause death of macrophages and formation of foam cells thereby increasing inflammation in atherosclerotic plaques. Accumulation of cholesterol in macrophages is another critical event that promotes development of inflammatory cardiovascular diseases. Several proteins are known to transport intracellular cholesterol outside of the cell and these proteins are thought to be protective against atherosclerosis pathogenesis. It is unknown whether TG can affect cholesterol efflux in macrophages. In the current study, we examined mRNA expression levels of genes that promote efflux of cholesterol (ABCA1, ABCG1 and SR-B1). We found that TG treated THP-1 macrophages exhibited an increase in ABCG1 expression in a dose- and time-dependent manner. In contrast, the expression of ABCA1 and SR-B1 remained unchanged. To identify cell signaling pathways that participate in up-regulation of ABCG1, THP-1 macrophages were treated with various cell signaling inhibitors. We found that inhibition of the JNK and p38 MAPK pathway completely abrogated up-regulation of ABCG1 whereas inhibition of MEK1 further enhanced ABCG1 expression in TG treated THP-1 macrophages. Also, TG induced phosphorylation of JNK and p38 MAPK in THP-1 macrophages. These results suggest that TG may potentially influence cholesterol efflux in macrophages.
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KEYWORD
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THP-1 macrophages, Triglyceride (TG), ABCG1, JNK, p38 MAPK
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