College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; National Research Institute for Family Planning, Beijing 100081, PR China.
College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
Ecotoxicol Environ Saf. 2023 Jul 1;259:115056. doi: 10.1016/j.ecoenv.2023.115056. Epub 2023 May 23.
Cadmium (Cd) is widespread globally in the environment as a toxic metal. Although it is well known to induce hepatotoxicity in the cells, defense mechanisms against the detrimental effects of Cd are still unknown. We examined the role of autophagy (a cellular defense mechanism) on Cd-induced cytotoxicity in bird hepatocytes. Primary chicken hepatocytes were cultured with different concentrations (0, 1, 2.5, 5, and 10 μM) of cadmium chloride (CdCl) for 12 h. We assessed the effects of CdCl on the cell viability, antioxidant status, reactive oxygen species (ROS) generation, autophagy response and endoplasmic reticulum (ER) stress. Further, it is also evaluated that insight into underling molecular mechanisms involved in the study. In this study, CdCl-induce hepatotoxicity was caused by drastically increased ROS generation as well as a reduction level of antioxidant enzymes. It was also demonstrated that marked activation of ER stress markers (GRP78, IRE1, PERK, ATF4, ATF6 and XBP-1 s) was observed. Simultaneously, increased activation of autophagy in low-dose CdCl (1 μM) exposed group was observed, but high-dose CdCl (10 μM) inhibited autophagy and significantly promoted apoptosis, as indicated by the expression of the autophagy related genes for P62, Beclin-1, ATG3, ATG5, ATG9, and the detection of autophagic vacuoles. Pretreatment with autophagy agonist Rapamycin (RAP) has successfully reduced ROS production, attenuated ER stress and enhanced hepatocytes viability, while the autophagy inhibitor 3-Methyladenine (3-MA) had the opposite effect. Hence, these findings stipulate that Cd could inhibit viability of hepatocytes in a dose-dependent manner. Autophagy relieves hepatotoxicity of Cd via reducing ROS generation and regulating ER stress. We identified autophagy as a novel protective mechanism involved in Cd-mediated chicken hepatotoxicity.
镉 (Cd) 作为一种有毒金属,在全球环境中广泛存在。尽管它已被广泛证实会导致细胞肝毒性,但针对 Cd 有害影响的防御机制仍不清楚。我们研究了自噬(一种细胞防御机制)在鸡肝细胞中对 Cd 诱导的细胞毒性的作用。用不同浓度(0、1、2.5、5 和 10 μM)的氯化镉 (CdCl) 培养原代鸡肝细胞 12 小时。我们评估了 CdCl 对细胞活力、抗氧化状态、活性氧 (ROS) 生成、自噬反应和内质网 (ER) 应激的影响。此外,还评估了研究中涉及的潜在分子机制。在这项研究中,CdCl 诱导的肝毒性是由 ROS 生成急剧增加以及抗氧化酶水平降低引起的。还表明,观察到 ER 应激标志物 (GRP78、IRE1、PERK、ATF4、ATF6 和 XBP-1s) 的明显激活。同时,在低剂量 CdCl(1 μM)暴露组中观察到自噬的明显激活,但高剂量 CdCl(10 μM)抑制自噬并显著促进凋亡,这表现在自噬相关基因 P62、Beclin-1、ATG3、ATG5、ATG9 的表达以及自噬空泡的检测。自噬激动剂雷帕霉素 (RAP) 的预处理成功降低了 ROS 的产生,减轻了 ER 应激并增强了肝细胞活力,而自噬抑制剂 3-甲基腺嘌呤 (3-MA) 则产生了相反的效果。因此,这些发现规定 Cd 可以以剂量依赖的方式抑制肝细胞活力。自噬通过减少 ROS 生成和调节 ER 应激来减轻 Cd 引起的肝毒性。我们确定自噬是一种参与 Cd 介导的鸡肝细胞毒性的新的保护机制。
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