Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon, Hong Kong SAR 999077, China.
Golden Meditech Center for NeuroRegeneration Sciences, Hong Kong Baptist University, Kowloon, Hong Kong SAR 999077, China.
Int J Mol Sci. 2022 Oct 21;23(20):12689. doi: 10.3390/ijms232012689.
We report herein a novel mechanism, unraveled by proteomics and validated by in vitro and in vivo studies, of the aberrant aging-associated upregulation of ovarian transferrin and ferritin in rat ovaries. The ovarian mass and serum estradiol titer plummeted while the ovarian labile ferrous iron and total iron levels escalated with age in rats. Oxidative stress markers, such as nitrite/nitrate, 3-nitrotyrosine, and 4-hydroxy-2-nonenal, accumulated in the aging ovaries due to an aberrant upregulation of the ovarian transferrin, ferritin light/heavy chains, and iron regulatory protein 2(IRP2)-mediated transferrin receptor 1 (TfR1). Ferritin inhibited estradiol biosynthesis in ovarian granulosa cells in vitro via the upregulation of a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and p65/p50-induced oxidative and inflammatory factor inducible nitric oxide synthase (iNOS). An in vivo study demonstrated how the age-associated activation of NF-κB induced the upregulation of iNOS and the tumor necrosis factor α (TNFα). The downregulation of the keap1-mediated nuclear factor erythroid 2-related factor 2 (Nrf2), that induced a decrease in glutathione peroxidase 4 (GPX4), was observed. The aberrant transferrin and ferritin upregulation triggered an iron accumulation via the upregulation of an IRP2-induced TfR1. This culminates in NF-κB-iNOS-mediated ovarian oxi-inflamm-aging and serum estradiol decrement in naturally aging rats. The iron accumulation and the effect on ferroptosis-related proteins including the GPX4, TfR1, Nrf2, Keap1, and ferritin heavy chain, as in testicular ferroptosis, indicated the triggering of ferroptosis. In young rats, an intraovarian injection of an adenovirus, which expressed iron regulatory proteins, upregulated the ovarian NF-κB/iNOS and downregulated the GPX4. These novel findings have contributed to a prompt translational research on the ovarian aging-associated iron metabolism and aging-associated ovarian diseases.
我们在此报告了一种新的机制，通过蛋白质组学揭示，并通过体外和体内研究得到验证，即大鼠卵巢中转铁蛋白和铁蛋白的异常衰老相关上调。随着大鼠年龄的增长，卵巢质量和血清雌二醇滴度骤降，而卵巢不稳定亚铁和总铁水平升高。由于卵巢转铁蛋白、铁蛋白轻/重链和铁调节蛋白 2(IRP2)介导的转铁蛋白受体 1(TfR1)的异常上调，导致氧化应激标志物如亚硝酸盐/硝酸盐、3-硝基酪氨酸和 4-羟基-2-壬烯醛在衰老卵巢中积累。铁蛋白通过上调核因子κB 轻链增强子的激活 B 细胞（NF-κB）和 p65/p50 诱导的氧化和炎症因子诱导型一氧化氮合酶（iNOS），在体外抑制卵巢颗粒细胞中的雌二醇生物合成。体内研究表明，与年龄相关的 NF-κB 激活如何诱导 iNOS 和肿瘤坏死因子α（TNFα）的上调。观察到 KEAP1 介导的核因子红细胞 2 相关因子 2（Nrf2）下调，导致谷胱甘肽过氧化物酶 4（GPX4）减少。异常的转铁蛋白和铁蛋白上调通过诱导 TfR1 的 IRP2 诱导来触发铁积累。这导致 NF-κB-iNOS 介导的卵巢氧化-炎症-衰老和自然衰老大鼠血清雌二醇减少。铁积累和对铁死亡相关蛋白的影响，包括 GPX4、TfR1、Nrf2、Keap1 和铁蛋白重链，如睾丸铁死亡，表明触发了铁死亡。在年轻大鼠中，卵巢内注射表达铁调节蛋白的腺病毒会上调卵巢 NF-κB/iNOS 并下调 GPX4。这些新发现促进了卵巢衰老相关铁代谢和衰老相关卵巢疾病的快速转化研究。
