Department of Cardiovascular Surgery, Wuhan Asia General Hospital.
Int Heart J. 2023 Nov 30;64(6):1125-1132. doi: 10.1536/ihj.23-333. Epub 2023 Nov 14.
This study aimed to observe the mechanism and effect of circ_0004771 on cardiomyocyte injury in acute myocardial infarction (AMI). The differences in circ_0004771 expression in the blood of AMI patients and healthy volunteers were observed by Real-Time Quantitative Reverse Transcription-Polymerase Chain Reaction. AMI cell models were constructed by hypoxia/reoxygenation (H/R)-induced injury in human cardiomyocytes (AC16 cells). The changes of circ_0004771 expression in AMI cells were observed. After transfection with the knockdown or overexpression of circ_0004771 vector in AMI cells, Cell Counting Kit-8 (CCK-8) assay and propidium iodide/FITC-Annexin V staining were performed to detect cell proliferation and apoptosis levels, extracellular lactate dehydrogenase (LDH) activity, malondialdehyde (MDA) concentration, and superoxide dismutase (SOD) activity. Expression levels of Mitogen-activated protein kinase (MAPK) signaling pathway-related proteins (p-MEK1/2, MEK1/2, p-ERK1/2, ERK1/2), and endoplasmic reticulum (ER) stress proteins (GRP78 and CHOP-1) were observed in each group of cells by western blot method. The expression level of circ_0004771 was significantly reduced in both clinical samples and cells of AMI. When circ_0004771 was knocked down in AMI cells, it resulted in a decrease in cell proliferation level and significant increase in apoptosis level. The inhibition of circ_0004771 expression caused leakage of LDH in AMI cells, accumulation of intracellular MDA, and inhibition of SOD activity. In addition, the knockdown of circ_0004771 significantly increased the levels of p-MEK1/2, p-ERK1/2, GRP78, and CHOP-1 in H/R-induced AC16 cells. However, the overexpression of circ_0004771 resulted in the opposite result as when circ_0004771 was knocked down. A low level of circ_0004771 in AMI activates the MAPK signaling pathway in cardiomyocytes as well as encourages intracellular oxidative stress and ER stress, thereby inhibiting cell proliferation and promoting apoptosis.
本研究旨在观察环状 RNA（circRNA）circ_0004771 对急性心肌梗死（AMI）中心肌细胞损伤的作用机制。通过实时定量逆转录聚合酶链反应观察 AMI 患者和健康志愿者血液中 circ_0004771 的表达差异。通过缺氧/复氧（H/R）诱导人心肌细胞（AC16 细胞）损伤构建 AMI 细胞模型。观察 AMI 细胞中 circ_0004771 的表达变化。在 AMI 细胞中转染 circ_0004771 载体的敲低或过表达后，通过细胞计数试剂盒-8（CCK-8）检测和碘化丙啶/荧光素 FITC-Annexin V 染色检测细胞增殖和凋亡水平、细胞外乳酸脱氢酶（LDH）活性、丙二醛（MDA）浓度和超氧化物歧化酶（SOD）活性。通过 Western blot 法观察各组细胞中丝裂原激活蛋白激酶（MAPK）信号通路相关蛋白（p-MEK1/2、MEK1/2、p-ERK1/2、ERK1/2）和内质网（ER）应激蛋白（GRP78 和 CHOP-1）的表达水平。在临床样本和 AMI 细胞中，circ_0004771 的表达水平均显著降低。在 AMI 细胞中敲低 circ_0004771 后，细胞增殖水平下降，凋亡水平显著升高。抑制 circ_0004771 的表达导致 AMI 细胞中 LDH 漏出、细胞内 MDA 积累和 SOD 活性抑制。此外，circ_0004771 的敲低显著增加了 H/R 诱导的 AC16 细胞中 p-MEK1/2、p-ERK1/2、GRP78 和 CHOP-1 的水平。然而，circ_0004771 的过表达导致与敲低 circ_0004771 时相反的结果。AMI 中 circ_0004771 水平低会激活心肌细胞中的 MAPK 信号通路，并促进细胞内氧化应激和 ER 应激，从而抑制细胞增殖并促进凋亡。
