Department of Vascular Surgery, the First Affiliated Hospital of Bengbu Medical College, Bengbu, China.
Department of General Surgery, Bengbu First People's Hospital, Bengbu, China.
J Cell Biochem. 2019 Sep;120(9):14405-14413. doi: 10.1002/jcb.28695. Epub 2019 Apr 15.
The main aim of our study was to investigate the roles and molecular basis of long noncoding RNA myocardial infarction associated transcript (MIAT) in the development of thoracic aortic aneurysm. RT-qPCR assay was performed to measure the expressions of MIAT, microRNA-145 (miR-145), along with Bcl-2 and Bcl-xl messenger RNAs. Western blot assay was conducted to determine protein levels of Bcl-2, Bcl-xl, phosphorylated-Akt (p-Akt), and total Akt (t-Akt). Cell viability was detected by the (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The relationship of MIAT and miR-145 was examined by bioinformatics analysis and luciferase reporter assay. MIAT expression was significantly increased, and miR-145 expression was markedly reduced in thoracic aortic aneurysms compared with normal thoracic aortic tissues. MIAT overexpression or miR-145 depletion improved cell viability and inhibited cell apoptosis in human aortic vascular smooth muscle cells (h-VSMCs). Further exploration revealed that MIAT could inhibit miR-145 expression by direct interaction. And miR-145 upregulation abrogated MIAT-induced viability increase and apoptosis inhibition in h-VSMCs. Moreover, MIAT inhibited the activation of Akt signaling, while this effect was abated by miR-145 overexpression in h-VSMCs. The inhibition of the Akt pathway by MK-22062HCl resulted in the reduction of cell viability and the increase of cell apoptotic activity in h-VSMCs. Akt activation by HY-18749 improved cell viability and suppressed cell apoptosis in h-VSMCs. And the introduction of HY-18749 raised cell viability and curbed cell apoptosis in h-VSMCs cotransfected with MIAT overexpression plasmid and miR-145 mimic. lncRNA-MIAT could target miR-145 to affect the viability and apoptosis of h-VSMCs, which was implicated in the regulation of the PI3K/Akt signaling pathway.
本研究的主要目的是探讨长链非编码 RNA 心肌梗死相关转录物（MIAT）在胸主动脉瘤发展中的作用和分子基础。通过 RT-qPCR 测定 MIAT、微小 RNA-145（miR-145）以及 Bcl-2 和 Bcl-xl 信使 RNA 的表达。通过 Western blot 测定 Bcl-2、Bcl-xl、磷酸化-Akt（p-Akt）和总 Akt（t-Akt）的蛋白水平。通过（3-（4,5-二甲基-2-噻唑基）-2,5-二苯基-2-H-四唑溴盐（MTT）测定细胞活力。通过生物信息学分析和荧光素酶报告基因测定检查 MIAT 和 miR-145 之间的关系。与正常胸主动脉组织相比，胸主动脉瘤中 MIAT 表达显著增加，miR-145 表达明显降低。MIAT 过表达或 miR-145 耗竭可提高人主动脉血管平滑肌细胞（h-VSMCs）的细胞活力并抑制细胞凋亡。进一步探索表明，MIAT 可通过直接相互作用抑制 miR-145 的表达。miR-145 的上调可消除 MIAT 诱导的 h-VSMCs 活力增加和凋亡抑制。此外，MIAT 抑制 Akt 信号通路的激活，而在 h-VSMCs 中转染 miR-145 过表达则减弱了这种作用。MK-22062HCl 抑制 Akt 通路导致 h-VSMCs 中细胞活力降低和细胞凋亡活性增加。HY-18749 激活 Akt 可提高 h-VSMCs 的细胞活力并抑制细胞凋亡。HY-18749 的引入可提高 h-VSMCs 中转染 MIAT 过表达质粒和 miR-145 模拟物的细胞活力并抑制细胞凋亡。lncRNA-MIAT 可以靶向 miR-145 来影响 h-VSMCs 的活力和凋亡，这与 PI3K/Akt 信号通路的调节有关。
