Institute of Molecular Genetics of National Research Centre "Kurchatov Institute", 123182 Moscow, Russia.
Int J Mol Sci. 2021 Jul 23;22(15):7906. doi: 10.3390/ijms22157906.
Regulated cell death (RCD) is a fundamental process common to nearly all living beings and essential for the development and tissue homeostasis in animals and humans. A wide range of molecules can induce RCD, including a number of viral proteolytic enzymes. To date, numerous data indicate that picornaviral 3C proteases can induce RCD. In most reported cases, these proteases induce classical caspase-dependent apoptosis. In contrast, the human hepatitis A virus 3C protease (3Cpro) has recently been shown to cause caspase-independent cell death accompanied by previously undescribed features. Here, we expressed 3Cpro in HEK293, HeLa, and A549 human cell lines to characterize 3Cpro-induced cell death morphologically and biochemically using flow cytometry and fluorescence microscopy. We found that dead cells demonstrated necrosis-like morphological changes including permeabilization of the plasma membrane, loss of mitochondrial potential, as well as mitochondria and nuclei swelling. Additionally, we showed that 3Cpro-induced cell death was efficiently blocked by ferroptosis inhibitors and was accompanied by intense lipid peroxidation. Taken together, these results indicate that 3Cpro induces ferroptosis upon its individual expression in human cells. This is the first demonstration that a proteolytic enzyme can induce ferroptosis, the recently discovered and actively studied type of RCD.
受调控的细胞死亡（RCD）是一种几乎存在于所有生物中的基本过程，对于动物和人类的发育和组织稳态至关重要。许多分子都可以诱导 RCD，包括一些病毒蛋白酶。迄今为止，大量数据表明，小核糖核酸病毒 3C 蛋白酶可以诱导 RCD。在大多数报道的情况下，这些蛋白酶诱导经典的半胱天冬酶依赖性细胞凋亡。相比之下，人类甲型肝炎病毒 3C 蛋白酶（3Cpro）最近被证明会引起非典型的半胱天冬酶依赖性细胞死亡，伴随着以前未描述的特征。在这里，我们在 HEK293、HeLa 和 A549 人细胞系中表达 3Cpro，使用流式细胞术和荧光显微镜从形态和生化角度来描述 3Cpro 诱导的细胞死亡。我们发现，死亡细胞表现出坏死样形态变化，包括质膜通透性增加、线粒体膜电位丧失以及线粒体和细胞核肿胀。此外，我们表明，3Cpro 诱导的细胞死亡可以被铁死亡抑制剂有效阻断，并且伴随着强烈的脂质过氧化。总之，这些结果表明 3Cpro 在人细胞中单独表达时会诱导铁死亡。这是第一个证明蛋白酶可以诱导铁死亡的实验，铁死亡是最近发现并正在积极研究的一种 RCD 类型。
