Nephrology Research and Training Center, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama.
Department of Surgery, University of Alabama at Birmingham , Birmingham, Alabama.
Am J Physiol Renal Physiol. 2018 May 1;314(5):F702-F714. doi: 10.1152/ajprenal.00044.2017. Epub 2017 May 17.
Ferroptosis is an iron-dependent form of regulated nonapoptotic cell death, which contributes to damage in models of acute kidney injury (AKI). Heme oxygenase-1 (HO-1) is a cytoprotective enzyme induced in response to cellular stress, and is protective against AKI because of its antiapoptotic and anti-inflammatory properties. However, the role of HO-1 in regulating ferroptosis is unclear. The purpose of this study was to elucidate the role of HO-1 in regulating ferroptotic cell death in renal proximal tubule cells (PTCs). Immortalized PTCs obtained from HO-1 and HO-1 mice were treated with erastin or RSL3, ferroptosis inducers, in the presence or absence of antioxidants, an iron source, or an iron chelator. Cells were assessed for changes in morphology and metabolic activity as an indicator of cell viability. Treatment of HO-1 PTCs with erastin resulted in a time- and dose-dependent increase in HO-1 gene expression and protein levels compared with vehicle-treated controls. HO-1 cells showed increased dose-dependent erastin- or RSL3-induced cell death in comparison to HO-1 PTCs. Iron supplementation with ferric ammonium citrate in erastin-treated cells decreased cell viability further in HO-1 PTCs compared with HO-1 cells. Cotreatment with ferrostatin-1 (ferroptosis inhibitor), deferoxamine (iron chelator), or N-acetyl-l-cysteine (glutathione replenisher) significantly increased cell viability and attenuated erastin-induced ferroptosis in both HO-1 and HO-1 PTCs. These results demonstrate an important antiferroptotic role of HO-1 in renal epithelial cells.
铁死亡是一种依赖铁的调节性非凋亡细胞死亡形式，它导致急性肾损伤 (AKI) 模型中的损伤。血红素加氧酶-1 (HO-1) 是一种细胞应激诱导的保护性酶，因其抗凋亡和抗炎特性而对 AKI 具有保护作用。然而，HO-1 在调节铁死亡中的作用尚不清楚。本研究旨在阐明 HO-1 在调节肾近端小管细胞 (PTC) 中铁死亡中的作用。从 HO-1 和 HO-1 小鼠中获得的永生化 PTC 用 erastin 或 RSL3（铁死亡诱导剂）处理，同时存在或不存在抗氧化剂、铁源或铁螯合剂。评估细胞形态和代谢活性的变化，作为细胞活力的指标。与 vehicle 处理的对照相比，用 erastin 处理的 HO-1 PTC 中 HO-1 基因表达和蛋白水平呈时间和剂量依赖性增加。与 HO-1 PTC 相比，HO-1 细胞中 erastin 或 RSL3 诱导的细胞死亡呈剂量依赖性增加。与 HO-1 细胞相比，在用 erastin 处理的细胞中补充 ferric ammonium citrate（铁源）进一步降低了 HO-1 PTC 的细胞活力。用 ferrostatine-1（铁死亡抑制剂）、 deferoxamine（铁螯合剂）或 N-acetyl-l-cysteine（谷胱甘肽补充剂）共同处理显着增加了细胞活力，并减轻了 HO-1 和 HO-1 PTC 中 erastin 诱导的铁死亡。这些结果表明 HO-1 在肾上皮细胞中具有重要的抗铁死亡作用。
