Abstract：
Copper (Cu) is a common trace element additive in animal and human foods, and excessive intake of Cu has been shown to cause hepatotoxicity, but the underlying mechanism remains unclear. Our previous research found that Cu exposure dramatically upregulated mitochondrial miR-12294-5p expression and confirmed its targeted inhibition of CISD1 expression in chicken hepatocytes. Thus, we aimed to explore the potential role of mitomiR-12294-5p/CISD1 axis in Cu exposure-resulted hepatotoxicity. Here, we observed that Cu exposure resulted in Cu accumulation and pathological injury in chicken livers. Moreover, we found that Cu exposure caused mitochondrial-dependent ferroptosis in chicken hepatocytes, which were prominent on the increased mitochondrial Fe2+ and mitochondrial lipid peroxidation, inhibited levels of CISD1, GPX4, DHODH, and IDH2, and also enhanced level of PTGS2. Notably, we identified that inhibition of mitomiR-2954 level effectively mitigated Cu-exposure-resulted mitochondrial Fe2+ accumulation and mitochondrial lipid peroxidation and prevented the development of mitochondrial-dependent ferroptosis. However, increasing the mitomiR-12294-5p expression considerably aggravated the influence of Cu on these indicators. Meanwhile, the overexpression of CISD1 effectively alleviated Cu-caused mitochondrial-dependent ferroptosis, while silent CISD1 eliminated the therapeutic role of mitomiR-12294-5p inhibitor. Overall, our findings indicated that mitomiR-12294-5p/CISD1 axis played a critical function in Cu-caused hepatotoxicity in chickens by regulating mitochondrial-dependent ferroptosis.
摘要：
铜（Cu）是动物和人类食品中常见的微量元素添加剂，过量摄入铜已被证明会导致肝毒性，但潜在的机制仍不清楚。我们之前的研究发现，铜暴露显著上调线粒体miR-12294-5p表达，并证实其在鸡肝细胞中靶向抑制CISD1表达。因此，我们旨在探讨mitomiR-12294-5p/CISD1轴在铜暴露导致的肝毒性中的潜在作用。这里,我们观察到铜暴露导致鸡肝脏中铜的积累和病理损伤。此外，我们发现铜暴露导致鸡肝细胞线粒体依赖性铁死亡，这对线粒体Fe2+和线粒体脂质过氧化的增加是显著的，抑制CISD1、GPX4、DHODH、和IDH2，也增强了PTGS2的水平。值得注意的是,我们发现,抑制mitomiR-2954水平可有效减轻Cu暴露导致的线粒体Fe2+积累和线粒体脂质过氧化,并阻止线粒体依赖性铁死亡的发展.然而,mitomiR-12294-5p表达的增加大大加剧了Cu对这些指标的影响。同时,CISD1的过表达有效缓解了铜引起的线粒体依赖性铁死亡，而silentCISD1消除了mitomiR-12294-5p抑制剂的治疗作用。总的来说,我们的发现表明mitomiR-12294-5p/CISD1轴通过调节线粒体依赖性铁死亡在铜引起的鸡肝毒性中发挥了关键功能。
