甜菊醇调控巨噬细胞ABCA1蛋白表达

ABCA1 Protein Expression in Macrophages Regulated by Steviol

摘要:

甜菊糖能够降低机体的胆固醇水平，而甜菊醇（steviol，STE）是甜菊糖在机体内的主要天然水解物。作者研究了甜菊醇对小鼠巨噬细胞J774A.1三磷酸腺苷结合盒转运体A1蛋白（ATP-binding cassette transporter A1，ABCA1）的调控作用，并探讨其可能的分子机制。首先，利用MTT方法建立了甜菊醇的使用条件及浓度。采用免疫蛋白印记、细胞免疫荧光以及荧光定量PCR方法，发现在环磷酸腺苷（cyclic adenosine monophosphate，cAMP）的类似物8-（4-硫代氯苯基）腺苷-3'，5'-环磷酸盐（8-（4-chlorophenylthio）adenosine 3'，5'-cyclic monophosphate，CPT）的协作下，甜菊醇能够显著提高ABCA1在蛋白质水平和基因转录水平的表达；且甜菊醇可以显著上调ABCA1的上游调控基因肝X受体（LXRα）和过氧化物酶体增殖物激活受体（PPARα）的mRNA表达水平和蛋白质表达水平，但对过氧化物酶体增殖物激活受体（PPARγ）的表达无明显调控作用。结果表明，甜菊醇能够调控ABCA1蛋白表达的机制，可能与PPARα、LXRα的表达有关。本研究为后续治疗和预防动脉粥样硬化具有指导意义，对甜菊糖食品的应用提供了一定的参考作用。

Abstract:

Stevioside is demonstrated to regulate the cholesterol levels in body. The steviol is the main natural hydrolysate of stevioside in the intestine. The regulation of adenosine triphosphate binding cassette transporter A1 protein (ABCA1) in mouse macrophages J774A via steviol was studied and its possible molecular mechanism was investigated. The conditions and concentration of steviol were first established by MTT method. The detection of western blot, immunofluorescence and quantitative fluorescence PCR confirmed that steviol could significantly increase the expression of ABCA1 at protein and gene transcription level in collaboration with 8-(4-chlorophenylthio) adenosine 3',5'-cyclic monophosphate (CPT), the analogue of cyclic adenosine monophosphate (cAMP). Moreover, steviol could significantly up-regulate the expression levels of both mRNA and protein in upstream regulatory genes LXRα and PPARα of ABCA1, however, insignificant regulation on the expression of PPARγ was observed. The regulation of the ABCA1 protein expression through steviol might be related to the expression of PPARα and LXRα. This study is extremely instructive to the subsequent treatment and prevention of atherosclerosis, providing a reference for the application of stevioside in food.