Relevance of oxidative stress for heme iron-triggered toxicity in intestinal cells and cellular defense mechanisms

氧化应激与血红素铁引发的肠细胞毒性和细胞防御机制的相关性

• 批准号: 527664508
• 负责人: Professor Dr. Jörg Fahrer
• 金额: --
• 依托单位: Fachrichtung Lebensmittelchemie / Toxikologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/527664508?language=en
• 关键词: Relevance; oxidative; stress; heme; iron

Dietary heme is an important iron source in human nutrition and occurs abundantly in red meat, whose excessive consumption is associated with an increased risk for colorectal cancer formation. Heme plays a central role in this process and promotes tumorigenesis via different mechanisms. It is known that heme iron causes oxidative stress and cytotoxicity in intestinal cells, while non-heme iron such as iron chloride exhibits only moderate effects. Using genetic and pharmacological approaches, we previously identified heme oxygenase-1 as an important factor in intestinal cells that confers protection against heme iron. However, the precise chemical nature of the reactive oxygen species (ROS) formed in intestinal cells as well as their spatio-temporal generation on the subcellular level is only little understood. Furthermore, it is unclear whether the antioxidant enzymes katalase (KAT), superoxide dismutase (SOD)-1 and SOD2 as well as perioxiredoxin-1 (PRDX1) are involved in the protection of intestinal cells against heme iron. The objective of this study is to investigate the fate of heme iron in intestinal cells, the spatio-temporal ROS generation and their relevance for gastrointestinal toxicity. In addition, the impact of potentially relevant antioxidant enzymes (KAT, SOD1, SOD2 and PRDX1) on these events will be studied. To this end, hemin (Fe3+-protoporphyrine) as well as inorganic iron(III)chloride and iron (II)sulfate as non-heme iron sources should be tested. Non-malignantly transformed human colonic epithelial cells and colorectal cancer cells should be used as cell models. Additionally, murine intestinal oragnoids and tumorids will be used. Based on our preliminary work, we would like to address the following issues: 1.) how is the fate of heme iron versus non-heme iron in intestinal cells and how the global proteome is affected by these iron species, 2.) in which cell compartment and kinetics arise which ROS upon exposure of intestinal cells to heme iron versus non-heme iron, and 3.) what is the impact of the antioxidant enzymes KAT, SOD1, SOD2 and PRDX1 in intestinal cells following treatment with heme iron and non-heme iron and how does their deficiency affect oxidative stress, toxicity and the global proteome in intestinal cells.

膳食血红素是人类营养中重要的铁源，大量存在于红肉中，过量食用红肉会增加结直肠癌形成的风险。血红素在此过程中起着核心作用，并通过不同的机制促进肿瘤发生。众所周知，血红素铁会引起肠细胞的氧化应激和细胞毒性，而氯化铁等非血红素铁仅表现出中等影响。通过遗传和药理学方法，我们之前发现血红素加氧酶-1 是肠道细胞中的一个重要因子，可提供针对血红素铁的保护。然而，人们对肠细胞中形成的活性氧（ROS）的精确化学性质以及它们在亚细胞水平上的时空生成知之甚少。此外，尚不清楚抗氧化酶过氧化氢酶（KAT）、超氧化物歧化酶（SOD）-1和SOD2以及过氧化还原蛋白-1（PRDX1）是否参与保护肠道细胞免受血红素铁的侵害。本研究的目的是研究肠细胞中血红素铁的命运、时空活性氧的产生及其与胃肠道毒性的相关性。此外，还将研究潜在相关的抗氧化酶（KAT、SOD1、SOD2 和 PRDX1）对这些事件的影响。为此，应测试血红素（Fe3+-原卟啉）以及无机氯化铁（III）和硫酸铁（II）作为非血红素铁源。应使用非恶性转化的人结肠上皮细胞和结直肠癌细胞作为细胞模型。此外，还将使用小鼠肠道类器官和肿瘤。根据我们的初步工作，我们希望解决以下问题：1.）肠细胞中血红素铁与非血红素铁的命运如何，以及这些铁种类如何影响全局蛋白质组，2.）当肠细胞暴露于血红素铁与非血红素铁时，细胞区室和动力学中产生哪些ROS，以及3.）抗氧化酶KAT、SOD1、 血红素铁和非血红素铁治疗后肠道细胞中的 SOD2 和 PRDX1 以及它们的缺乏如何影响肠道细胞中的氧化应激、毒性和整体蛋白质组。