Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, 250014, China.
Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, 266021, China.
J Biomed Sci. 2023 Jun 27;30(1):45. doi: 10.1186/s12929-023-00927-1.
Emerging research has reported that circular RNAs (circRNAs) play important roles in cardiac cell death after myocardial ischemia and reperfusion (I/R). Ferroptosis, a new form of cell death discovered in recent years, has been proven to participate in the regulation of myocardial I/R. This study used circRNA sequencing to explore the key circRNA in the regulation of cardiac ferroptosis after I/R and study the mechanisms of potential circRNA function.
We performed circRNA sequencing to explore circRNAs differentially expressed after myocardial I/R. We used quantitative polymerase chain reactions to determine the circRNA expression in different tissues and detect the circRNA subcellular localization in the cardiomyocyte. Gain- and loss-of-function experiments were aimed to examine the function of circRNAs in cardiomyocyte ferroptosis and cardiac tissue damage after myocardial I/R. RNA pull-down was applied to explore proteins interacting with circRNA.
Here, we identified a ferroptosis-associated circRNA (FEACR) that has an underlying regulatory role in cardiomyocyte ferroptosis. FEACR overexpression suppressed I/R-induced myocardial infarction and ameliorated cardiac function. FEACR inhibition induces ferroptosis in cardiomyocytes and FEACR overexpression inhibits hypoxia and reoxygenation-induced ferroptosis. Mechanistically, FEACR directly bound to nicotinamide phosphoribosyltransferase (NAMPT) and enhanced the protein stability of NAMPT, which increased NAMPT-dependent Sirtuin1 (Sirt1) expression, which promoted the transcriptional activity of forkhead box protein O1 (FOXO1) by reducing FOXO1 acetylation levels. FOXO1 further upregulated the transcription of ferritin heavy chain 1 (Fth1), a ferroptosis suppressor, which resulted in the inhibition of cardiomyocyte ferroptosis.
Our finding reveals that the circRNA FEACR-mediated NAMPT-Sirt1-FOXO1-FTH1 signaling axis participates in the regulation of cardiomyocyte ferroptosis and protects the heart function against I/R injury. Thus, FEACR and its downstream factors could be novel targets for alleviating ferroptosis-related myocardial injury in ischemic heart diseases.
新兴研究表明，环状 RNA（circRNA）在心肌缺血再灌注（I/R）后心肌细胞死亡中发挥重要作用。铁死亡是近年来发现的一种新的细胞死亡形式，已被证明参与了心肌 I/R 的调节。本研究使用 circRNA 测序技术来探讨 I/R 后调节心肌铁死亡的关键 circRNA，并研究潜在 circRNA 功能的机制。
我们进行了 circRNA 测序，以探索心肌 I/R 后差异表达的 circRNA。我们使用定量聚合酶链反应来确定不同组织中的 circRNA 表达，并检测心肌细胞中 circRNA 的亚细胞定位。增益和缺失功能实验旨在研究 circRNA 在心肌细胞铁死亡和心肌 I/R 后心脏组织损伤中的功能。RNA 下拉技术用于探索与 circRNA 相互作用的蛋白质。
在这里，我们鉴定了一个与铁死亡相关的 circRNA（FEACR），它在心肌细胞铁死亡中具有潜在的调节作用。FEACR 过表达抑制 I/R 诱导的心肌梗死并改善心脏功能。FEACR 抑制诱导心肌细胞铁死亡，而 FEACR 过表达抑制缺氧再复氧诱导的铁死亡。机制上，FEACR 直接与烟酰胺磷酸核糖基转移酶（NAMPT）结合并增强 NAMPT 的蛋白稳定性，从而增加 NAMPT 依赖性 Sirtuin1（Sirt1）的表达，通过降低 FOXO1 乙酰化水平促进 FOXO1 的转录活性。FOXO1 进一步上调铁死亡抑制因子 ferritin heavy chain 1（Fth1）的转录，从而抑制心肌细胞铁死亡。
我们的发现表明，circRNA FEACR 介导的 NAMPT-Sirt1-FOXO1-FTH1 信号轴参与调节心肌细胞铁死亡，并保护心脏功能免受 I/R 损伤。因此，FEACR 及其下游因子可能成为缓解缺血性心脏病中铁死亡相关心肌损伤的新靶点。
