Role of ATP-binding cassette transporter A1 in suppressing lipid accumulation by glucagon-like peptide-1 agonist in hepatocytes
Role of ATP-binding cassette transporter A1 in suppressing lipid accumulation by glucagon-like peptide-1 agonist in hepatocytes
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DOI：
10.1016/j.molmet.2019.12.015
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发表时间：
2020-04-01
影响因子：
8.1
通讯作者：
Murao, Koji
中科院分区：
文献类型：
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作者：
Lyu, Jingya;Imachi, Hitomi;Murao, Koji
目的：三磷酸腺苷（ATP）结合盒转运体A1（ABCA 1）影响肝脏胆固醇转运。肝脏胆固醇的积累导致脂肪肝疾病，糖尿病中的胰高血糖素样肽1（GLP-1）可改善脂肪肝疾病。方法：采用免疫印迹法、荧光素酶法和实时荧光定量PCR法检测GLP-1类似物exendin-4对HepG 2细胞中ABCA 1表达和转录的影响。染色质免疫沉淀（ChIP）和定点突变，以确定ABCA 1基因的转录调控。产生催乳素调节元件结合（PREB）转基因小鼠以评估exendin-4对改善由高脂饮食（HFD）引起的脂质积累的作用。Exendin-4通过Ca 2 +/CaM依赖性蛋白激酶激酶/CaM依赖性蛋白激酶IV刺激肝脏ABCA 1表达和转录（CaMKK/CaMKIV）途径，而GLP-1受体拮抗剂exendin 9 -39取消了这种作用。因此，exendin-4降低肝脏脂质含量。ChIP显示PREB可以直接结合ABCA 1启动子，这是由exendin-4增强。此外，PREB刺激ABCA 1启动子活性，ABCA 1启动子中PREB结合位点的突变取消exendin-4增强的ABCA 1启动子活性。PREB的沉默减弱了exendin-4的作用并诱导肝胆固醇蓄积。通过STO-609或siRNA阻断CaMKK可取消exendin-4诱导的ABCA 1和PREB的上调。在体内，exendin-4或过表达的PREB增加肝脏ABCA 1的表达和减少肝脏脂质积聚和高血浆胆固醇引起的HFD.Conclusions：我们的数据显示，exendin-4刺激肝脏ABCA 1的表达和减少脂质积聚的CaMKK/CaMKIV/PREB途径，这表明ABCA 1和PREB可能是脂肪肝疾病的治疗靶点。(C)2020作者（S）由爱思唯尔有限公司出版。
Objective: Adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) influences hepatic cholesterol transportation. Accumulation of hepatic cholesterol leads to fatty liver disease, which is improved by glucagon-like peptide 1 (GLP-1) in diabetes. Therefore, we analyzed the molecular mechanism in the regulation of hepatic ABCA1 by GLP-1 analogue exendin-4.Methods: Hepatic ABCA1 expression and transcription were checked by western blotting, real-time polymerase chain reaction (PCR), and luciferase assay in HepG2 cells. Chromatin immunoprecipitation (ChIP) and site-directed mutagenesis were employed to determine transcriptional regulation of the ABCA1 gene. Prolactin regulatory element-binding (PREB)-transgenic mice were generated to access the effect of exendin-4 on improving lipid accumulation caused by a high-fat diet (HFD).Results: Exendin-4 stimulated hepatic ABCA1 expression and transcription via the Ca2+/calmodulin (CaM)-dependent protein kinase kinase/CaM-dependent protein kinase IV (CaMKK/CaMKIV) pathway, whereas GLP-1 receptor antagonist exendin9-39 cancelled this effect. Therefore, exendin-4 decreased hepatic lipid content. ChIP showed that PREB could directly bind to the ABCA1 promoter, which was enhanced by exendin-4. Moreover, PREB stimulated ABCA1 promoter activity, and mutation of PREB-binding site in ABCA1 promoter cancelled exendin-4-enhanced ABCA1 promoter activity. Silencing of PREB attenuated the effect of exendin-4 and induced hepatic cholesterol accumulation. Blockade of CaMKK by STO-609 or siRNA cancelled the upregulation of ABCA1 and PREB induced by exendin-4. In vivo, exendin-4 or overexpression of PREB increased hepatic ABCA1 expression and decreased hepatic lipid accumulation and high plasma cholesterol caused by a HFD.Conclusions: Our data shows that exendin-4 stimulates hepatic ABCA1 expression and decreases lipid accumulation by the CaMKK/CaMKIV/PREB pathway, suggesting that ABCA1 and PREB might be the therapeutic targets in fatty liver disease. (C) 2020 The Author(s). Published by Elsevier GmbH.