*The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia.
†School of Medicine, Discipline of Surgery, and Centre for Clinical Research, University of Queensland, and Department of Vascular Surgery, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia.
Clin Sci (Lond). 2014 Oct;127(7):475-84. doi: 10.1042/CS20130784.
Current efforts to identify the genetic contribution to abdominal aortic aneurysm (AAA) have mainly focused on the assessment of germ-line variants such as single-nucleotide polymorphisms. The aim of the present study was to assess the presence of acquired chromosomal aberrations in human AAA. Microarray data of ten biopsies obtained from the site of main AAA dilatation (AAA body) and three control biopsies obtained from the macroscopically non-dilated neck of the AAA (AAA neck) were initially compared with identified chromosomal aneuploidies using the Chromosomal Aberration Region Miner (ChARM) software. A commonly deleted segment of chromosome bands 6 (q22.1-23.2) was predicted within AAA biopsies. This finding was confirmed by quantitative real-time PCR (qPCR)-based DNA copy number assessments of an independent set of six AAA body and neck biopsies which identified a fold copy number change (∆KCt) of -1±0.35, suggesting the loss of one copy of the long interspersed nucleotide element type 1 (LINE-1) mapped to chromosome 6 (q22.1-23.2). The median relative genomic content of LINE-1 DNA was also reduced in AAA body compared with AAA neck biopsies (1.540 compared with 3.159; P=0.031). A gene important for vascular homoeostasis mapped to 6q23.1, connective tissue growth factor (CTGF), was assessed and found to be significantly down-regulated within AAA bodies compared with AAA necks (0.261 compared with 0.627; P=0.031), as determined by reverse transcription qPCR using total RNA as a template. Histology demonstrated marked staining for macrophages within AAA body biopsies. We found in vitro that the median relative genomic content of LINE-1 DNA in aortic vascular smooth muscle cells (AoSMCs) exposed to pro-inflammatory medium was ~1.5 times greater than that measured in control AoSMCs exposed to non-conditioned medium (3.044 compared with 2.040; P=0.015). Our findings suggest that acquired chromosomal aberrations associated with retrotransposon propagation may predispose to sporadic AAA.
目前，识别腹主动脉瘤（AAA）遗传贡献的努力主要集中在评估单核苷酸多态性等种系变异。本研究旨在评估人类 AAA 中获得性染色体异常的存在。使用染色体异常区域挖掘器（ChARM）软件，最初将从 AAA 扩张部位（AAA 体）获得的十个活检样本和从宏观上未扩张的 AAA 颈部（AAA 颈部）获得的三个对照活检样本的微阵列数据与已识别的染色体非整倍体进行比较。在 AAA 活检中预测到染色体带 6（q22.1-23.2）的常见缺失片段。这一发现通过对六个 AAA 体和颈部活检的独立定量实时 PCR（qPCR）基于 DNA 拷贝数评估得到了证实，该评估确定了折叠拷贝数变化（∆KCt）为-1±0.35，提示 1 号长散在核苷酸元件类型 1（LINE-1）的一个拷贝丢失，该元素映射到染色体 6（q22.1-23.2）。与 AAA 颈部活检相比，AAA 体中的 LINE-1 DNA 中位相对基因组含量也降低（1.540 与 3.159；P=0.031）。与血管稳态相关的重要基因，即连接组织生长因子（CTGF），映射到 6q23.1，在 AAA 体中与 AAA 颈部相比明显下调（0.261 与 0.627；P=0.031），这是通过使用总 RNA 作为模板的逆转录 qPCR 确定的。组织学显示 AAA 体活检中的巨噬细胞明显染色。我们在体外发现，暴露于促炎介质的主动脉血管平滑肌细胞（AoSMCs）中的 LINE-1 DNA 中位相对基因组含量比暴露于非条件介质的 AoSMCs 中测量的高出约 1.5 倍（3.044 与 2.040；P=0.015）。我们的研究结果表明，与逆转座子增殖相关的获得性染色体异常可能导致散发性 AAA。
