Acrolein is a highly reactive α,β-unsaturated aldehyde and is known to react with DNA forming exocyclic acrolein−deoxyguanosine adducts (Acro−dG). These aldehyde−DNA lesions may play a role in mutagenesis, carcinogenesis, and neurodegenerative diseases. In the present work, we described the development and evaluation of a highly sensitive and selective capillary liquid chromatography nanoelectrospray isotope dilution tandem mass spectrometry method for quantitatively analyzing Acro−dG in DNA hydrolysates. This was achieved by applying a stable isotope-labeled analogue Acro−dG-13C10,15N5 as an internal standard to the DNA to be analyzed and then hydrolyzing the DNA enzymatically to nucleosides. The acrolein-modified nucleosides were separated from normal nucleosides by capillary liquid chromatography and quantified by a high-capacity ion trap mass spectrometer in the MS/MS mode. The developed method achieved attomole-level sensitivity (limit of detection was 10 fg, 31 amol on column) for detection of pure Acro−dG adduct standards. The limit of quantification of Acro−dG adducts obtained in 10 μg of DNA hydrolysates was 1.5 fmol, which corresponded to 50 adducts/109 normal nucleosides. Application of this method to the analysis of Acro−dG adducts in acrolein (10-fold)-treated calf thymus DNA showed ∼830 lesion/106 DNA nucleosides using as low as 50 ng of DNA. Application of this method to DNA samples (1−2 μg) isolated from brain tissues from Alzheimer's disease subjects and age-matched controls demonstrated 2800−5100 Acro−dG adducts/109 DNA nucleosides. Statistically significant differences (P < 0.05) in levels of Acro−dG between AD subjects and controls were observed in DNA isolated from the hippocampus/parahippocampal gyrus.
丙烯醛是一种高反应性 α,β-不饱和醛,已知会与 DNA 反应形成环外
丙烯醛-脱氧
鸟苷加合物 (Acro-dG)。这些醛-DNA 损伤可能在诱变、致癌和神经退行性疾病中发挥作用。在目前的工作中,我们描述了用于定量分析 DNA
水解产物中 Acro−dG 的高灵敏度和选择性毛细管
液相色谱纳电喷雾同位素稀释串联质谱方法的开发和评估。这是通过将稳定同位素标记的类似物 Acro−dG-13C10,15N5 作为内标应用于待分析的 DNA,然后将 DNA 酶促
水解为核苷来实现的。通过毛细管
液相色谱将
丙烯醛修饰的核苷与正常核苷分离,并通过高容量离子阱质谱仪在 MS/MS 模式下进行定量。所开发的方法实现了阿托摩尔
水平的灵敏度(检测限为 10 fg,柱上 31 amol),用于检测纯 Acro−dG 加合物标准品。 10 μg DNA
水解产物中获得的 Acro−dG 加合物的定量限为 1.5 fmol,相当于 50 个加合物/109 个正常核苷。应用该方法分析
丙烯醛(10 倍)处理的小牛胸腺 DNA 中的 Acro−dG 加合物,结果显示,使用低至 50 ng 的 DNA 即可发现约 830 个损伤/106 个 DNA 核苷。将该方法应用于从阿尔茨海默病受试者和年龄匹配对照的脑组织中分离的 DNA 样本(1−2 μg),结果显示有 2800−5100 个 Acro−dG 加合物/109 个 DNA 核苷。从海马/海马旁回分离的 DNA 中观察到 AD 受试者和对照组之间 Acro−dG
水平存在统计学显着差异 (P < 0.05)。