Diabetic cataract is a common complication of diabetes. The epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is a key event in the development of diabetic cataracts. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to be highly expressed in different tissues of diabetic patients. This study is aimed at investigating the function and mechanism of MALAT1 in the regulation of EMT in human LECs under high glucose conditions. MALAT1, α-smooth muscle actin (α-SMA), fibronectin (FN), and nuclear factor erythroid-derived 2-like 2 (NRF2) were highly expressed in the LECs of diabetic cataract patients and in the human LECs under high glucose conditions; meanwhile, the decreased expressions of E-cadherin and zonula occludens 1 (ZO-1) were detected. Knockdown of MALAT1 could significantly reduce ROS, prevent EMT, arrest S phase cell cycle, and suppress the expression of total NRF2 and its nucleus translocation in LECs. Furthermore, after NRF2 was knocked down, total NRF2, α-SMA, and FN in cells, and NRF2, Notch intracellular domain (NICD), and Snail were decreased in the nucleus. Using bioinformatics methods, we predicted that MALAT1 and NRF2 shared the same microRNA-144-3p (miR-144-3p) combining site. Luciferase reporter coupled with qRT-PCR assays revealed that miR-144-3p was a target of MALAT1, which was confirmed to downregulate miR-144-3p in the LECs. In addition, after transfection of miR-144-3p mimics or inhibitor, western blot assay demonstrated that miR-144-3p negatively regulated the expression of total NRF2, α-SMA, and FN in cells, and NRF2, NICD, and Snail in the nucleus without affecting Kelch-like ECH-associated protein 1 (KEAP1). Finally, we confirmed that transfection of shMALAT1 inhibited NRF2 expression, and its mediated EMT could be rescued by miR-144-3p inhibitor; transfection of pcDNA3.1-MALAT1 promoted NRF2 expression, and its mediated EMT could be reversed by miR-144-3p inhibitor. In summary, we demonstrate that MALAT1 regulates miR-144-3p to facilitate EMT of LECs via the ROS/NRF2/Notch1/Snail pathway.

中文翻译：

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LncRNA MALAT1调节miR-144-3p，以通过ROS / NRF2 / Notch1 / Snail通路促进晶状体上皮细胞的上皮-间质转化

糖尿病性白内障是糖尿病的常见并发症。晶状体上皮细胞（LECs）的上皮-间质转化（EMT）是糖尿病性白内障发展的关键事件。据报道，与转移有关的肺腺癌转录本1（MALAT 1）在糖尿病患者的不同组织中高表达。这项研究旨在调查在高葡萄糖条件下，MALAT 1在调节人LEC中EMT的功能和机制。MALAT 1，α-平滑肌肌动蛋白（α-SMA），纤连蛋白（FN）和核因子类红血球来源的2样2（NRF2）在糖尿病性白内障患者的LEC和高葡萄糖条件下的人LEC中高表达；同时，检测到E-cadherin和zonula occludens 1（ZO-1）的表达下降。敲低MALAT 1可以显着降低ROS，预防EMT，阻止S期细胞周期并抑制LECs中总NRF2的表达及其核易位。此外，敲低NRF 2后，细胞中的总NRF2，α- SMA和FN以及核中的NRF2，Notch胞内域（NICD）和Snail减少。使用生物信息学方法，我们预测MALAT 1和NRF2个共享相同的microRNA-144-3p（miR-144-3p）结合位点。加上的qRT-PCR测定萤光素酶报道揭示的miR-144-3p是的目标MALAT 1，其被证实为下调的miR-144-3p在淋巴管内皮细胞。此外，在转染miR-144-3p模拟物或抑制剂后，western blot分析表明，miR-144-3p负调控细胞中总NRF2，α- SMA和FN的表达，以及NRF2，NICD和Snail的表达。在不影响Kelch样ECH相关蛋白1（KEAP1）的情况下，细胞核。最后，我们证实转染sh MALAT 1抑制了NRF2表达，其介导的EMT可以被miR-144-3p抑制剂挽救。pcDNA3.1- MALAT转染1促进NRF2表达，其介导的EMT可以被miR-144-3p抑制剂逆转。总之，我们证明了MALAT 1通过ROS / NRF2 / Notch1 / Snail途径调节miR-144-3p促进LEC的EMT。