Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, No.1838 North Guangzhou Avenue, Baiyun District, Guangzhou, 510515, Guangdong, People's Republic of China.
Department of Thoracic Surgery, Yuebei People's Hospital, Shantou University, Shaoguan, 512026, Guangdong, People's Republic of China.
Mol Med. 2021 Feb 10;27(1):14. doi: 10.1186/s10020-021-00271-w.
Myocardial ischemia is the most common form of cardiovascular disease and the leading cause of morbidity and mortality. Understanding the mechanisms is very crucial for the development of effective therapy. Therefore, this study aimed to investigate the functional roles and mechanisms by which ELAVL1 regulates myocardial ischemia and reperfusion (I/R) injury.
Mouse myocardial I/R model and cultured myocardial cells exposed to hypoxia/reperfusion (H/R) were used in this study. Features of ferroptosis were evidenced by LDH activity, GPx4 activity, cellular iron, ROS, LPO, and GSH levels. The expression levels of autophagy markers (Beclin-1, p62, LC3), ELAVL1 and FOXC1 were measured by qRT-PCR, immunostaining and western blot. RIP assay, biotin-pull down, ChIP and dual luciferase activity assay were employed to examine the interactions of ELAVL1/Beclin-1 mRNA and FOXC1/ELAVL1 promoter. CCK-8 assay was used to examine viability of cells. TTC staining was performed to assess the myocardial I/R injury.
Myocardial I/R surgery induced ferroptosis and up-regulated ELAVL1 level. Knockdown of ELAVL1 decreased ferroptosis and ameliorated I/R injury. Si-ELAVL1 repressed autophagy and inhibition of autophagy by inhibitor suppressed ferroptosis and I/R injury in myocardial cells. Increase of autophagy could reverse the effects of ELAVL1 knockdown on ferroptosis and I/R injury. ELAVL1 directly bound with and stabilized Beclin-1 mRNA. Furthermore, FOXC1 bound to ELAVL1 promoter region and activated its transcription upon H/R exposure.
FOXC1 transcriptionally activated ELAVL1 may promote ferroptosis during myocardial I/R by modulating autophagy, leading to myocardial injury. Inhibition of ELAVL1-mediated autophagic ferroptosis would be a new viewpoint in the treatment of myocardial I/R injury.
心肌缺血是最常见的心血管疾病形式，也是发病率和死亡率的主要原因。了解其机制对于开发有效的治疗方法非常重要。因此，本研究旨在探讨 ELAVL1 调节心肌缺血再灌注（I/R）损伤的功能作用和机制。
本研究采用小鼠心肌 I/R 模型和缺氧/复氧（H/R）培养的心肌细胞。通过 LDH 活性、GPx4 活性、细胞铁、ROS、LPO 和 GSH 水平来证明铁死亡的特征。通过 qRT-PCR、免疫染色和 Western blot 测定自噬标志物（Beclin-1、p62、LC3）、ELAVL1 和 FOXC1 的表达水平。采用 RIP 测定、生物素下拉、ChIP 和双荧光素酶活性测定来检测 ELAVL1/Beclin-1 mRNA 和 FOXC1/ELAVL1 启动子之间的相互作用。CCK-8 测定用于检测细胞活力。TTC 染色用于评估心肌 I/R 损伤。
心肌 I/R 手术后诱导铁死亡并上调 ELAVL1 水平。ELAVL1 敲低可减少铁死亡并改善 I/R 损伤。Si-ELAVL1 抑制自噬，而自噬抑制剂抑制铁死亡和心肌细胞中的 I/R 损伤。自噬的增加可以逆转 ELAVL1 敲低对铁死亡和 I/R 损伤的影响。ELAVL1 直接与 Beclin-1 mRNA 结合并稳定其表达。此外，FOXC1 结合到 ELAVL1 启动子区域并在 H/R 暴露时激活其转录。
FOXC1 转录激活的 ELAVL1 通过调节自噬促进心肌 I/R 期间的铁死亡，导致心肌损伤。抑制 ELAVL1 介导的自噬性铁死亡可能为治疗心肌 I/R 损伤提供新的观点。
