DNA methylation and RASSF4 expression are involved in T-2 toxin-induced hepatotoxicity
DNA methylation and RASSF4 expression are involved in T-2 toxin-induced hepatotoxicity
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DNA甲基化和RASSF4表达参与T-2毒素诱导的肝毒性
DOI：
10.1016/j.tox.2019.152246
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发表时间：
2019-09-01
期刊：
影响因子：
4.5
通讯作者：
Yuan, Zonghui
中科院分区：
文献类型：
--
作者：
Liu, Aimei;Xu, Xiaoqing;Yuan, Zonghui
T-2毒素是镰刀菌产生的次生代谢物，通常污染食品和动物饲料。T-2毒素通过细胞凋亡和氧化应激诱导肝毒性；然而，其潜在机制尚不清楚。最近的研究表明，RASSF4是RASSF家族的一员，它通过DNA超甲基化失活参与细胞凋亡和一些癌症。然而，其在T-2毒素诱导的肝毒性中的作用尚不清楚。因此，在本研究中，雌性Wistar大鼠被给予2 mg/kg b.w.的单剂量T-2毒素，并在暴露后1、3和7天处死。将正常大鼠肝细胞系（BRL）分别暴露于不同浓度的T-2毒素（10、20、40 nM） 4、8、12 h。组织病理学分析显示，在T-2毒素暴露下，部分肝细胞凋亡和明显增生。免疫组化、实时荧光定量PCR （qPCR）和western blot分析结果显示，T-2毒素激活了PI3K-Akt/Caspase/NF-kappa B信号通路。此外，DNA甲基化分析显示，与对照组相比，暴露于T-2毒素1天和3天后，RASSF4的表达被启动子超甲基化沉默。此外，5- aza -2′-脱氧胞苷（DAC） （5 μ M）和T-2毒素（40 nM）联合处理可增加RASSF4和PI3K-Akt/caspase/NF-kappa B信号通路相关基因的表达，诱导细胞凋亡。这些发现首次证明了DNA甲基化调节T-2毒素下RASSF4的表达，并激活其下游通路，导致细胞凋亡。
T-2 toxin is a secondary metabolite produced by Fusarium species and commonly contaminates food and animal feed. T-2 toxin can induce hepatotoxicity through apoptosis and oxidative stress; however, the underlying mechanism is not clear. Recent studies indicated that RASSF4, a member of the RASSF family, participates in cell apoptosis and some cancers due to its inactivation via DNA hypermethylation. However, its role in T-2 toxininduced liver toxicity is poorly understood. Therefore, in this study, female Wistar rats were given a single dose of T-2 toxin at 2 mg/kg b.w. and were sacrificed at 1, 3 and 7 days post-exposure. A normal rat liver cell line (BRL) was exposed to different concentrations of T-2 toxin (10, 20, 40 nM) for 4, 8, 12 h, respectively. Histopathological analysis revealed with apoptosis in some liver cells and clear proliferation under T-2 toxin exposure. Expression analysis by immunohistochemical assays, quantitative real-time PCR (qPCR) and westem blot demonstrated that T-2 toxin activated PI3K-Akt/Caspase/NF-kappa B signaling pathways. Additionally, DNA methylation assays revealed that the expression of RASSF4 was silenced by promoter hypermethylation after exposure to T-2 toxin for 1 and 3 days as compared to the control group. Moreover, joint treatment of 5-Aza-2'-deoxycytidine (DAC) (5 mu M) and T-2 toxin (40 nM) increased expression of RASSF4 and PI3K-Akt/caspase/NF-kappa B signaling pathways-related genes, inducing cell apoptosis. These findings for the first time demonstrated that DNA methylation regulated the RASSF4 expression under T-2 toxin, along with the activation of its downstream pathways, resulting in apoptosis.