*The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, Queensland 4811, Australia.
†University of Queensland, School of Medicine, Discipline of Surgery, and Centre for Clinical Research and Royal Brisbane and Women's Hospital, Department of Vascular Surgery Herston, Queensland 4006, Australia.
Clin Sci (Lond). 2014 Jun;126(11):795-803. doi: 10.1042/CS20130599.
AAA (abdominal aortic aneurysm) is a potentially life-threatening late-onset degenerative condition. miRNAs (microRNAs), the small non-coding RNA molecules that regulate gene expression, have been shown previously to be associated with a broad range of human pathologies, including cardiovascular diseases. The aim of the present study was to identify AAA-associated miRNAs potentially contributing to AAA pathology. We analysed the expression of 124 miRNAs within AAA biopsies and serum of ten patients undergoing AAA repair, and serum from ten age- and sex-matched subjects without AAA, using the FlexmiR™ MicroRNA Assay. RNA extracted from the site of main AAA dilatation (AAA body) was compared with that extracted from the macroscopically non-dilated neck of the AAA (AAA neck). Similarly, RNA extracted from the serum of AAA patients (AAA serum) was compared with that extracted from age- and sex-matched controls (control serum). qPCR (quantitative real-time PCR), Western blot analysis and histology were performed using an independent set of six paired AAA body and neck biopsies to examine the validity of findings. Seven miRNAs were up-regulated [>2-fold difference, FDR (false discovery rate) <0.5] within AAA biopsies, of which miR-155 was the most differentially expressed (11.32-fold, FDR=0.414). This finding was confirmed by qPCR with the median relative expression of miR-155 being 3.26 and 0.63 within AAA body and AAA neck biopsies respectively (P=0.031). Circulating miR-155 was also increased in AAA patients compared with controls, with a 2.67-fold up-regulation at borderline significance (FDR=0.554). Two immunologically important miR-155 target genes, CTLA4 (cytotoxic T-lymphocyte-associated protein) and SMAD2, were assessed and found to be significantly down-regulated within AAA bodies compared with AAA necks (P=0.032 and P=0.026) as determined by qPCR and Western blotting respectively. Histology demonstrated dense accumulation of T-lymphocytes within the adventitial and outer medial layers of AAA body, but not neck tissue. The results of the present study suggest that miR-155 is overexpressed in AAA with potential implications in the pathogenesis of the condition.
AAA（腹主动脉瘤）是一种潜在危及生命的迟发性退行性疾病。miRNAs（microRNAs）是调节基因表达的小非编码 RNA 分子，先前已被证明与广泛的人类病理学相关，包括心血管疾病。本研究的目的是鉴定与 AAA 病理相关的潜在 miRNA。我们使用 FlexmiR™MicroRNA 检测分析了 10 名接受 AAA 修复手术的患者 AAA 活检和血清中 124 个 miRNA 的表达情况，以及 10 名年龄和性别匹配的无 AAA 患者的血清中的 miRNA 表达情况。从 AAA 主要扩张部位（AAA 体）提取的 RNA 与从宏观上非扩张的 AAA 颈部（AAA 颈部）提取的 RNA 进行比较。同样，从 AAA 患者的血清（AAA 血清）中提取的 RNA 与年龄和性别匹配的对照（对照血清）中提取的 RNA 进行比较。使用一组独立的 6 对 AAA 体和颈部活检进行 qPCR（定量实时 PCR）、Western blot 分析和组织学检查，以检查发现的有效性。在 AAA 活检中，有 7 个 miRNA 上调[>2 倍差异，FDR（假发现率）<0.5]，其中 miR-155 的表达差异最大（11.32 倍，FDR=0.414）。qPCR 验证了这一发现，miR-155 在 AAA 体和 AAA 颈部活检中的中位相对表达分别为 3.26 和 0.63（P=0.031）。与对照组相比，AAA 患者的循环 miR-155 也增加，FDR=0.554 时有边界显著性的 2.67 倍上调。评估了两个免疫上重要的 miR-155 靶基因 CTLA4（细胞毒性 T 淋巴细胞相关蛋白）和 SMAD2，并通过 qPCR 和 Western blot 分别发现它们在 AAA 体中与 AAA 颈部相比显著下调（P=0.032 和 P=0.026）。组织学显示 AAA 体的外膜和中层中有密集的 T 淋巴细胞堆积，但颈部组织没有。本研究的结果表明，miR-155 在 AAA 中过度表达，这可能对该疾病的发病机制有影响。
