National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Department of Biosciences, COMSATS University Islamabad, Sahiwal Campus, Pakistan.
Food Chem Toxicol. 2019 Oct;132:110661. doi: 10.1016/j.fct.2019.110661. Epub 2019 Jul 3.
Currently, T-2 toxin has been reported to cause liver toxicity with the effects of oxidative stress and inflammation; however, the underlying mechanism of T-2 toxin-induced liver injury is not fully understood. Increasing lines of evidence show that DNA methylation affects the expression of inflammatory cytokine, and plays a crucial role in autoimmune diseases. Nevertheless, the potential role of DNA methylation in the hepatotoxicity of T-2 toxin has not been explored. 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. In vitro, a normal rat liver cell line (BRL) was exposed to different concentrations of T-2 toxin. Histopathological analysis was used to investigate damage to the liver, which was detected at the molecular level by RT-PCR, Western blot and immunohistochemical assays, methylation-specific PCR (MSP), bisulfite sequencing (BSP), and flow cytometry. The results showed that T-2 toxin significantly increased the levels of DNA methyltransferases (DNMT1, DNMT3A), which were mainly concentrated at the site of liver injury. The 5-methylcytosine (5-mC) level of genomic DNA was also raised in T-2 toxin-treated rat livers. The expression of inflammatory cytokines (IL-6, IL-1β, IL-11, IL-1α, and TNF-α) increased both in vivo and in vitro under T-2 toxin treatment. Notably, DNA demethylation directly increased the expression of cytokines IL-11, IL-6, IL-α, and TNF-α under T-2 toxin exposure. DNA methylation inhibitors combined with T-2 toxin directly or indirectly induced the production of inflammatory cytokines and aggravate cell apoptosis. Our study uncovered for the first time that DNA methylation is related to the expression of inflammatory cytokines in T-2 toxin-induced liver injury. These findings suggested that DNA methylation is a potential mechanism of T-2 toxin-induced hepatotoxicity.
目前，已有报道称 T-2 毒素可引起肝毒性，其作用机制与氧化应激和炎症有关；然而，T-2 毒素诱导肝损伤的潜在机制尚未完全阐明。越来越多的证据表明，DNA 甲基化影响炎症细胞因子的表达，并在自身免疫性疾病中发挥关键作用。然而，DNA 甲基化在 T-2 毒素肝毒性中的潜在作用尚未得到探索。在这项研究中，雌性 Wistar 大鼠单次给予 T-2 毒素 2mg/kg bw，分别在染毒后 1、3 和 7 天处死。体外，正常大鼠肝细胞系（BRL）暴露于不同浓度的 T-2 毒素。采用 RT-PCR、Western blot 和免疫组化检测，甲基化特异性 PCR（MSP）、亚硫酸氢盐测序（BSP）和流式细胞术等分子水平检测肝损伤，分析 T-2 毒素对肝脏的损伤。结果表明，T-2 毒素显著增加了 DNA 甲基转移酶（DNMT1、DNMT3A）的水平，这些酶主要集中在肝损伤部位。T-2 毒素处理的大鼠肝脏中基因组 DNA 的 5-甲基胞嘧啶（5-mC）水平也升高。T-2 毒素处理后，体内和体外的炎症细胞因子（IL-6、IL-1β、IL-11、IL-1α 和 TNF-α）表达均增加。值得注意的是，DNA 去甲基化直接增加了 T-2 毒素暴露下细胞因子 IL-11、IL-6、IL-α 和 TNF-α 的表达。DNA 甲基化抑制剂联合 T-2 毒素直接或间接诱导炎症细胞因子产生并加重细胞凋亡。本研究首次揭示了 DNA 甲基化与 T-2 毒素诱导肝损伤中炎症细胞因子的表达有关。这些发现表明 DNA 甲基化是 T-2 毒素诱导肝毒性的潜在机制。
