铁自噬与铁死亡及其相关疾病

铁是血红素、线粒体呼吸链复合体和各种生物酶的重要辅助因子,参与氧气运输、氧化还原反应和代谢物合成等生物过程。铁蛋白(ferritin)是一种铁存储蛋白质,通过储存和释放铁来维持机体内铁平衡。铁自噬(ferritinophagy)作为一种选择性自噬方式,介导铁蛋白降解释放游离铁,参与细胞内铁含量的调控。适度铁自噬维持细胞内铁含量稳定,但铁自噬过度会释放出大量游离铁。通过芬顿 (Fenton)反应催化产生大量的活性氧(reactive oxygen species, ROS),发生脂质过氧化造成细胞受损。因此,铁自噬在维持细胞生理性铁稳态中发挥至关重要的作用。核受体共激活因子4 (nuclear receptor co-activator 4, NCOA4)被认为是铁自噬的关键调节因子,与铁蛋白靶向结合,并传递至溶酶体中降解释放游离铁,其介导的铁自噬构成了铁代谢的重要组成部分。最新研究表明,NCOA4受体内铁含量、自噬、溶酶体和低氧等因素的调控。NCOA4介导的铁蛋白降解与铁死亡(ferroptosis)有关。铁死亡是自噬性细胞死亡过程。铁自噬通过调节细胞铁稳态和细胞ROS生成,成为诱导铁死亡的上游机制,与贫血、神经退行性疾病、癌症、缺血/再灌注损伤与疾病的发生发展密切相关。本文针对NCOA4介导的铁自噬通路在铁死亡中的功能特征,探讨NCOA4在这些疾病中的作用,可能为相关疾病的治疗提供启示。

The Research on Ferritinophagy,Ferroptosis and Related Diseases

Iron, an important cofactor for heme, mitochondrial respiratory chain complexes, and various biologically important enzymes, participates in biological processes including oxygen transport, redox reactions, and metabolite synthesis. Ferritin is an iron storage protein that maintains iron homeostasis in the body by sequestering and releasing iron. Ferritinophagy is a selective type of autophagy that mediates ferritin degradation, releasing free iron when increased intracellular iron level is needed. Moderate rates of iron autophagy maintain intracellular iron content homeostasis. Excessive ferritinophagy will release a large amount of free iron, causing lipid peroxidation and cell damage via reactive oxygen species (ROS) produced by the Fenton reaction. Therefore, ferritinophagy plays a vital role in maintaining cellular iron homeostasis. Nuclear receptor co-activator 4 (NCOA4) acts as a key regulator of ferritinophagy by targeting ferritin binding and delivery to lysosomes for degradation, leading to release of free iron. Thus, NCOA4-mediated ferritinophagy is an important contributor to iron metabolism. Recent research reveals that NCOA4 is regulated by factors including iron content, autophagy, lysosomes, and hypoxia. NCOA4-mediated ferritin degradation is related to ferroptosis (an autophagic cell death process). Ferritinophagy acts as an upstream mechanism driving ferroptosis by regulating cellular iron homeostasis and ROS production, which are closely correlated with the occurrence and development of anemia, neurodegenerative diseases, cancer, ischemia/reperfusion injury, and other diseases. In this study, the functional characteristics of NCOA4-mediated ferritinophagy in ferroptosis and the role of NCOA4 in these diseases were reviewed, which may provide new avenues for the treatment of related diseases.