镉(Cd)是一种有毒重金属,可通过工业活动排放到水环境中,威胁水生生物和人类的健康。MicroRNA(miRNA)在自噬过程中发挥重要作用。本实验旨在研究Cd诱导鲤鱼肝胰腺自噬的机制。我们建立了鲤鱼镉中毒模型,并探索了超微结构,两个氧化指标,三个抗氧化指标,miR-25-3p,两种热休克蛋白(Hsps),和9个自噬相关基因。结果证实,Cd的有害作用引起了鲤鱼肝胰腺的损伤和肝胰腺自噬细胞的出现。同时,Cd暴露增加了过氧化氢(H2O2)和丙二醛(MDA)的含量,并降低过氧化氢酶(CAT)的活性,超氧化物歧化酶(SOD),和总抗氧化能力(T-AOC),这意味着Cd通过过氧化物水平和抗氧化能力之间的不平衡引起氧化应激。此外,暴露于Cd会增加微管相关蛋白-1轻链3β(LC3-II)的mRNA表达,Dynein,Beclin1,自噬相关基因5(Atg5),和自噬相关基因12(Atg12);降低雷帕霉素激酶机制靶点(mTOR)的mRNA表达,表明过量的Cd引起自噬,AMPK/mTOR/ULK1信号通路参与了Cd诱导的鲤鱼肝胰腺自噬。此外,Cd下调miR-25-3p并上调其三个靶基因(AMPK,ULK1以及PTEN),提示miR-25-3p介导Cd诱导的自噬。此外,我们发现Hsps通过Hsp70和Hsp90的上调而被激活。此外,在Cd处理的鲤鱼肝胰腺中,氧化应激通过Hsps介导的自噬和Cd诱导的自噬具有时间依赖性。总之,miR-25-3p,氧化应激,Hsps参与了Cd引起的鲤鱼肝胰腺自噬。本研究为探讨Cd诱导肝胰腺自噬的机制提供了新的思路。
Cadmium (Cd) is a toxic heavy metal that can be discharged into water environment through industrial activities, threatening the health of aquatic organisms and humans. MicroRNA (miRNA) plays an important role in the process of autophagy. The purpose of this experiment was to study the mechanism of Cd-induced autophagy in common carp hepatopancreas. We established a Cd poisoning model of common carp and explored ultrastructure, two oxidation indicators, three antioxidant indicators, miR-25-3p, two heat shock proteins (Hsps), and nine autophagy-related genes. The results confirmed that deleterious effect of Cd caused the injury of hepatopancreas and the appearance of hepatopancreas autophagic cells in common carp. At the same time, Cd exposure increased the contents of hydrogen peroxide (H2O2) and malonaldehyde (MDA), and decreased the activities of catalase (CAT), superoxide dismutase (SOD), and total antioxidative capacity (T-AOC), meaning that Cd caused oxidative stress via the imbalance between peroxide level and antioxidant capacity. Moreover, exposure to Cd increased mRNA expression of microtubule associated protein-1 light chain 3 beta (LC3-II), Dynein, Beclin 1, autophagy-related gene 5 (Atg5), and autophagy-related gene 12 (Atg12); and decreased mRNA expression of mechanistic target of rapamycin kinase (mTOR), indicating that excess Cd caused autophagy, and AMPK/mTOR/ULK1 signaling pathway took part in autophagy induced by Cd in common carp hepatopancreas. Furthermore, Cd down-regulated miR-25-3p and up-regulated its three target genes (AMPK, ULK1 as well as PTEN), suggesting that miR-25-3p mediated autophagy induced by Cd. In addition, we found that Hsps were activated via the up-regulation of Hsp70 and Hsp90. Moreover, oxidative stress mediated autophagy via Hsps in Cd-treated common carp hepatopancreas and Cd-induced autophagy was time dependent. In summary, miR-25-3p, oxidative stress, and Hsps participated in autophagy caused by Cd in common carp hepatopancreas. This study provided a new idea for the mechanism of Cd-induced autophagy in hepatopancreas.