MiR-486 Regulates Cholesterol Efflux By Targeting HAT1

[Objective] Atherosclerosis(As) is the underlying pathological of cardiovascular diseases(CVD). It has been the first cause of death among Chinese, and endangered the human health seriously. ATP binding cassette transporter A1(ABCA1) is a key protein which can mediate intracellular cholesterol, and plays an important role in the restrain of atherosclerosis. Histone Acetyltransferase 1(HAT1) is an enzyme that can promote histone acetylation. Researches show that there are many factors can effect atherosclerosis, such as epigenetics, but the affection of transcription and expression of ABCA1 by histone acetylation is not clear, meanwhile, the affection of intracellular cholesterol, the formation of foam cells and development of atherosclerosis has not been elucidated, either. The purpose of this study is to determine whether mi R-486 regulates ATP-binding cassette transporter A1(ABCA1) — mediated cholesterol efflux, and also explore the underlying mechanism in THP-1 macrophage.[Methods] Using real-time polymerase chain reaction(RT PCR) and Weston Blot to detect the m RNA and protein level of ABCA1 in THP-1 macrophage derived foam cell, respectively. Weston Blot is used to detect the protein level of HAT1 and acetylation level of H4K5 and H4K12. To predict and judge the combination site of mi R-486, we take advantage of the online bioinformatics website. After that, we transfect the mi R-486 mimic and mi R-486 inhibitor to THP-1 macrophage derived foam cell, respectively. To detect the condition of intracellular cholesterol efflux, we use the Liquid Scintillation Counter. And then we use the high performance Liquid chromatography(HPLC) to detect the content of cholesterol in the macrophage.[Results] Based on bioinformatics analysis and luciferase reporter assay, we transfected mi R-486 mimic and mi R-486 inhibitor into THP-1–derived foam cells, and found that mi R-486 directly bound to histone acetyltransferase-1(HAT1) 3'UTR, and downregulated its m RNA and protein expression. In addition, our studies through transfection with wildtype HAT1 or sh HAT1 revealed that HAT1 could promote the expression of ABCA1 at both m RNA and protein levels. At the same time, the acetylation levels of the lysines 5 and 12 of histone H4 were upregulated after overexpression with HAT1. Meanwhile, the results of liquid scintillation counter and high performance liquid chromatography(HPLC) showed that mi R-486 promoted cholesterol accumulation in THP-1 macrophages.[Conclusion] These data indicated that mi R-486 aggravate the cholesterol accumulation in THP-1 cells by targeting HAT1.