Aloe-emodin induces hepatotoxicity by the inhibition of multidrug resistance protein 2
Aloe-emodin induces hepatotoxicity by the inhibition of multidrug resistance protein 2
复制标题
芦荟大黄素通过抑制多药耐药蛋白2诱导肝毒性
DOI：
10.1016/j.phymed.2019.153148
复制
发表时间：
2020-03-01
期刊：
影响因子：
7.9
通讯作者：
Meng Xian-li
中科院分区：
文献类型：
--
作者：
Liu De-ming;Yang Dong;Meng Xian-li
研究背景：芦荟大黄素（AE）是传统中药大黄（RheumpalmatumL.）中的主要蒽醌类化合物。多药耐药蛋白2（ABCC 2/MRP 2）是一种重要的细胞氧化应激相关物质外排转运蛋白。目的：探讨ABCC 2在AE肝毒性中的作用。方法：采用Western-Blotting和qRT-PCR方法分别检测ABCC 2蛋白和mRNA的表达。通过定量细胞内活性氧、丙二醛、还原型和氧化型谷胱甘肽的水平来评估AE引起的细胞内氧化应激。通过检测线粒体三磷酸腺苷、线粒体膜电位和线粒体DNA水平，探讨AE对线粒体功能的影响。流式细胞仪检测AE对细胞凋亡及细胞周期的影响。为了进一步阐明ABCC 2在AE诱导的细胞毒性中的关键作用，我们利用pCI-neo-ABCC 2质粒过表达ABCC 2蛋白，并利用小干扰RNA（siRNA）敲低HepG 2细胞中的ABCC 2。结果：AE可抑制ABCC 2转运活性，下调ABCC 2表达，改变细胞内氧化还原平衡。氧化应激导致细胞内还原型谷胱甘肽耗竭、线粒体功能障碍和细胞凋亡激活。ABCC 2过表达显著降低AE诱导的细胞内氧化应激和细胞死亡，这是由ABCC 2敲低增强。此外，AE通过诱导自噬促进ABCC 2降解，并通过促进ABCC 2降解诱导小鼠肝毒性。结论：抑制ABCC 2是AE触发氧化应激和细胞凋亡的一种新效应。这些发现有助于了解含AE药用植物的毒理学效应。
Background: Aloe-emodin (AE) is among the primary bioactive anthraquinones present in traditional Chinese medicinal plants such as Rheum palmatum L. Multidrug resistance protein 2 (ABCC2/ MRP2) is an important efflux transporter of substances associated with cellular oxidative stress. However, the effects of traditional Chinese medicine on this protein remain unclear.Purpose: The aim of this research is to study the role of ABCC2 in AE-induced hepatotoxicity.Methods: The expression of ABCC2 protein and mRNA levels were analyzed by Western-Blotting and qRT-PCR, respectively. The intracellular oxidative stress caused by AE was evaluated by quantifying the levels of intracellular reactive oxygen species, malondialdehyde, glutathione reduced and oxidized glutathione. The levels of adenosine triphosphate, mitochondrial membrane potential and mitochondrial DNA were explored to evaluate the effects of AE on mitochondrial function. The effects of AE on cell apoptosis and cell cycle were detected by flow cytometry. To further clarify the key role of ABCC2 in AE induced cytotoxicity, we used pCI-neo-ABCC2 plasmid to over express ABCC2 protein, and small interfering RNA was used to knockdown ABCC2 in HepG2 cells. Additionally, we investigated the impact of AE on ABCC2 degradation pathway and the hepatotoxic effects of AE in mice.Results: AE was found to inhibit ABCC2 transport activity, downregulate ABCC2 expression and altered intracellular redox balance. Induction of oxidative stress resulted in depletion of intracellular glutathione reduced, mitochondria dysfunction and activation of apoptosis. ABCC2 overexpression significantly reduced AE-induced intracellular oxidative stress and cell death, which was enhanced by ABCC2 knockdown. Furthermore, AE was observed to promote ABCC2 degradation through induction of autophagy and hepatotoxicity was induced in mice by promoting ABCC2 degradation.Conclusions: The inhibition of ABCC2 is a novel effect of AE that triggers oxidative stress and apoptosis. These findings are helpful in understanding the toxicological effects of AE-containing medicinal plants.