Cao Xue, Cai Zhenguo, Liu Junyan, Zhao Yanru, Wang Xin, Li Xueqi, Xia Hongyuan
Department of Cardiology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150006, P.R. China.
Mol Med Rep. 2017 Sep;16(3):2570-2578. doi: 10.3892/mmr.2017.6873. Epub 2017 Jun 28.
Abdominal aortic aneurysm (AAA) is a common disease that is associated with the proliferation and apoptosis of vascular smooth muscle cells (VSMCs). VSMCs are regulated by microRNAs (miRNA). The aim of the present study was to identify miRNA sequences that regulate aortic SMCs during AAA. miRNA‑504 was identified using a miRNA PCR array and by reverse transcription‑quantitative polymerase chain reaction analysis, and its expression levels were observed to be downregulated in the aortic cells derived from patients with AAA when compared with controls. Transfection of SMCs with pMSCV‑miRNA‑504 vector was performed, and cell proliferation and the expression levels of proliferating cell nuclear antigen (PCNA), replication factor C subunit 4 (RFC4), B‑cell lymphoma‑2 (Bcl‑2) and caspase‑3/9 were measured by western blotting. The mechanisms underlying the effects of miRNA‑504 was then analyzed. The results demonstrated that overexpression of miRNA‑504 significantly upregulated the expression levels of PCNA, RFC4 and Bcl‑2, while caspase‑3/9 expression was significantly inhibited when compared with non‑targeting controls. In addition, miRNA‑504 overexpression was observed to promote the proliferation of SMCs. The expression level of the tumor suppressor, p53, which is known to be a direct target of miRNA‑504, was inhibited following transfection of SMCs with pMSCV‑miRNA‑504. In addition, the expression of the downstream targets of p53, p21 and Bcl‑like protein‑4, were significantly reduced following overexpression of miRNA‑504. These results revealed the anti‑apoptotic role of miRNA‑504 in SMCs derived from patients with AAA via direct targeting of p53.
腹主动脉瘤（AAA）是一种常见疾病，与血管平滑肌细胞（VSMC）的增殖和凋亡相关。VSMC受微小RNA（miRNA）调控。本研究的目的是鉴定在AAA形成过程中调节主动脉平滑肌细胞的miRNA序列。使用miRNA PCR阵列并通过逆转录-定量聚合酶链反应分析鉴定出miRNA-504，观察发现与对照组相比，其在AAA患者来源的主动脉细胞中的表达水平下调。用pMSCV-miRNA-504载体转染平滑肌细胞，通过蛋白质印迹法检测细胞增殖以及增殖细胞核抗原（PCNA）、复制因子C亚基4（RFC4）、B细胞淋巴瘤-2（Bcl-2）和半胱天冬酶-3/9的表达水平。随后分析miRNA-504发挥作用的机制。结果表明，与非靶向对照相比，miRNA-504过表达显著上调了PCNA、RFC4和Bcl-2的表达水平，同时半胱天冬酶-3/9的表达受到显著抑制。此外，观察到miRNA-504过表达可促进平滑肌细胞增殖。已知作为miRNA-504直接靶点的肿瘤抑制因子p53的表达水平，在用pMSCV-miRNA-504转染平滑肌细胞后受到抑制。此外，miRNA-504过表达后，p53的下游靶点p21和Bcl-2样蛋白4的表达显著降低。这些结果揭示了miRNA-504通过直接靶向p53在AAA患者来源的平滑肌细胞中发挥抗凋亡作用。
