Huang Xianwei, Pan Mandong, Du Penghui, Chen Yinrong, Zhang Caixia, Lu Wang, Lin Jiyan
Emergency Department, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Ann Transl Med. 2021 Jan;9(2):122. doi: 10.21037/atm-20-6438.
Cardiac arrest (CA), a common disease with a high mortality rate, is a leading cause of ischemia/reperfusion (I/R)-induced dysfunction of the intestinal barrier. Long non-coding RNAs (lncRNAs) play crucial roles in multiple pathological processes. However, the effect of the lncRNA maternally expressed 3 (MEG3) on intestinal I/R injury and the intestinal barrier has not been fully determined. Therefore, this study aimed to investigate the function of MEG3 in CA-induced intestinal barrier dysfunction.
The oxygen and glucose deprivation (OGD) model in the human colorectal adenocarcinoma Caco-2 cells and cardiac arrest-induced intestinal barrier dysfunction model in Sprague-Dawley (SD) rats were established. The effect and underlying mechanism of MEG3 on the intestinal barrier from cardiac arrest-induced ischemia/reperfusion injury were analyzed by methyl thiazolyl tetrazolium (MTT) assays, Annexin V-FITC/PI apoptosis detection kit, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining, quantitative polymerase chain reaction (qPCR) assays, Western blot analysis, luciferase reporter gene assays, transepithelial electrical resistance (TEER) measurements, immunofluorescence analysis, and enzyme-linked immunosorbent assay (ELISA) assays.
Interestingly, we found that MEG3 could protect Caco-2 cells from oxygen-glucose deprivation (OGD)/reoxygenation-induced I/R injury by modulating cell proliferation and apoptosis. Moreover, MEG3 relieved OGD-induced intestinal barrier dysfunction , as demonstrated by its significant rescue effect on transepithelial electrical resistance and the expression of tight junction proteins such as occludin and claudin-1 (CLDN1), which were impaired in OGD-treated Caco-2 cells. Mechanistically, MEG3 inhibited the expression of inflammatory factors including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, interferon-gamma (IFN)-γ, inflammatory factors including interleukin (IL)-10, and transforming growth factor beta (TGFb)-1, as well as nuclear factor-kappa B (NF-κB) signaling. In response to OGD treatment , MEG3 also activated the expression of sirtuin 1 (SIRT1) by Caco-2 cells via sponging miR-34a-3p. Furthermore, MEG3 relieved CA-induced intestinal barrier dysfunction through NF-κB signaling .
LncRNA MEG3 can protect the intestinal barrier from cardiac arrest-induced I/R injury via miR-34a-3p/SIRT1/NF-κB signaling. This finding provides new insight into the mechanism by which MEG3 restores intestinal barrier function following I/R injury, presenting it as a potential therapeutic candidate or strategy in intestinal injury.
心脏骤停（CA）是一种常见且死亡率高的疾病，是缺血/再灌注（I/R）诱导的肠屏障功能障碍的主要原因。长链非编码RNA（lncRNAs）在多种病理过程中发挥关键作用。然而，lncRNA母系表达基因3（MEG3）对肠道I/R损伤和肠屏障的影响尚未完全明确。因此，本研究旨在探讨MEG3在CA诱导的肠屏障功能障碍中的作用。
建立人结肠腺癌Caco-2细胞氧糖剥夺（OGD）模型和Sprague-Dawley（SD）大鼠心脏骤停诱导的肠屏障功能障碍模型。通过甲基噻唑基四氮唑（MTT）法、膜联蛋白V-FITC/PI凋亡检测试剂盒、末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）染色、定量聚合酶链反应（qPCR）法、蛋白质印迹分析、荧光素酶报告基因检测、跨上皮电阻（TEER）测量、免疫荧光分析和酶联免疫吸附测定（ELISA）法，分析MEG3对心脏骤停诱导的缺血/再灌注损伤所致肠屏障的作用及潜在机制。
有趣的是，我们发现MEG3可通过调节细胞增殖和凋亡保护Caco-2细胞免受氧糖剥夺（OGD）/复氧诱导的I/R损伤。此外，MEG3减轻了OGD诱导的肠屏障功能障碍，这体现在其对跨上皮电阻以及紧密连接蛋白如闭合蛋白和紧密连接蛋白-1（CLDN1）表达的显著挽救作用上，这些蛋白在OGD处理的Caco-2细胞中受损。机制上，MEG3抑制包括白细胞介素（IL）-1β、肿瘤坏死因子（TNF）-α、干扰素-γ（IFN）-γ等炎性因子以及白细胞介素（IL）-10和转化生长因子β（TGFβ）-1等炎性因子的表达，以及核因子-κB（NF-κB）信号传导。响应OGD处理，MEG3还通过海绵吸附miR-34a-3p激活Caco-2细胞中沉默调节蛋白1（SIRT1）的表达。此外，MEG3通过NF-κB信号传导减轻CA诱导的肠屏障功能障碍。
LncRNA MEG3可通过miR-34a-3p/SIRT1/NF-κB信号传导保护肠屏障免受心脏骤停诱导的I/R损伤。这一发现为MEG3在I/R损伤后恢复肠屏障功能的机制提供了新的见解，表明其作为肠损伤潜在治疗候选物或策略的可能性。
