Department of Cardiology, Linyi People's Hospital, Linyi, People's Republic of China.
Department of Critical Care Medicine, Aerospace Center Hospital (Aerospace Clinical Medical College of Peking University), Beijing, People's Republic of China.
Am J Physiol Heart Circ Physiol. 2021 Mar 1;320(3):H969-H979. doi: 10.1152/ajpheart.00304.2020. Epub 2020 Nov 8.
Myocardial infarction (MI) is recognized as a major cause of death and disability around the world. Macrophage-derived extracellular vesicles (EVs) have been reportedly involved in the regulation of cellular responses to MI. Thus, we sought to clarify the mechanism by which macrophage-derived EVs regulate this process. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to determine microRNA-150 (miR-150) expression in an MI mouse model with ligation of the left anterior descending coronary artery (LAD) and in hypoxia/reoxygenation (H/R)-exposed cardiomyocytes. Bioinformatics analysis and dual luciferase reporter gene assay were adopted to identify the correlation of miR-150 with tumor protein 53 (TP53) expression in cardiomyocytes. Gain- and loss-of-function experiments were conducted in H/R-induced cardiomyocytes, cardiomyocytes incubated with EVs from miR-150 mimic-transfected macrophages, or MI-model mice treated with EVs from miR-150 mimic-transfected macrophages. hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining assays were used for detecting inflammatory infiltration and cell apoptosis. The release of lactate dehydrogenase (LDH) by dead cardiomyocytes was measured with an LDH kit, and the apoptosis-related proteins, Bax, and cleaved-caspase 3 were determined by Western blot analysis. miR-150 expression was downregulated in the infarcted cardiac tissues of MI mice. Macrophage-derived EVs could transfer miR-150 into cardiomyocytes, where it directly targeted and suppressed TP53. Furthermore, miR-150 suppressed phosphatase and tensin homology (PTEN) and activated p-Akt to upregulate IGF-1 expression. Furthermore, increased expression of EV-derived miR-150 prevented cardiomyocyte apoptosis in vitro, as evidenced by downregulated Bax and cleaved-caspase 3 and upregulated Bcl2 and alleviated MI in vivo. In conclusion, our study demonstrates the cardioprotective effect of macrophage-derived EV-miR-150 on MI-induced heart injury through negatively regulating the TP53-IGF-1 signaling pathway. miR-150 is expressed at a low level in cardiac tissues after myocardial infarction. Macrophages-derived EVs transfer miR-150 to cardiomyocytes. miR-150 directly targets TP53. miR-150 elevation regulates TP53-IGF-1 axis to reduce cardiomyocyte apoptosis. EV-derived miR-150 could be a potential therapeutic target for myocardial infarction.
心肌梗死（MI）被认为是全世界死亡和残疾的主要原因。据报道，巨噬细胞衍生的细胞外囊泡（EVs）参与了细胞对 MI 的反应的调节。因此，我们试图阐明巨噬细胞衍生的 EVs 调节这一过程的机制。通过左前降支冠状动脉（LAD）结扎的 MI 小鼠模型和缺氧/复氧（H/R）暴露的心肌细胞中进行逆转录定量聚合酶链反应（RT-qPCR），以确定 microRNA-150（miR-150）的表达。采用生物信息学分析和双荧光素酶报告基因检测，鉴定 miR-150 与心肌细胞中肿瘤蛋白 53（TP53）表达的相关性。在 H/R 诱导的心肌细胞、用 miR-150 模拟物转染的巨噬细胞衍生的 EV 孵育的心肌细胞或用 miR-150 模拟物转染的巨噬细胞衍生的 EV 处理的 MI 模型小鼠中进行增益和失能实验。苏木精-伊红（HE）和末端脱氧核苷酸转移酶介导的 dUTP-生物素缺口末端标记（TUNEL）染色检测炎症浸润和细胞凋亡。用 LDH 试剂盒测量死亡心肌细胞释放的乳酸脱氢酶（LDH），并用 Western blot 分析测定凋亡相关蛋白 Bax 和 cleaved-caspase 3。miR-150 在 MI 小鼠的梗死心脏组织中表达下调。巨噬细胞衍生的 EV 可将 miR-150 转染至心肌细胞，在心肌细胞中，miR-150 直接靶向并抑制 TP53。此外，miR-150 抑制磷酸酶和张力蛋白同源物（PTEN）并激活 p-Akt 以上调 IGF-1 的表达。此外，体外增加 EV 衍生的 miR-150 的表达可通过下调 Bax 和 cleaved-caspase 3 并上调 Bcl2 来减轻 MI 小鼠的心肌细胞凋亡。综上所述，本研究表明巨噬细胞衍生的 EV-miR-150 通过负调控 TP53-IGF-1 信号通路对 MI 诱导的心脏损伤具有心脏保护作用。心肌梗死后心肌组织中 miR-150 的表达水平较低。巨噬细胞衍生的 EV 将 miR-150 转移至心肌细胞。miR-150 直接靶向 TP53。miR-150 的上调调节 TP53-IGF-1 轴以减少心肌细胞凋亡。EV 衍生的 miR-150 可能是心肌梗死的潜在治疗靶点。
