Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
J Proteome Res. 2010 Jul 2;9(7):3574-82. doi: 10.1021/pr100088k.
Down syndrome (DS) is an anomaly caused by an extra chromosome 21, and it affects 1 in 750 live births. Phenotypes include cognitive impairment, congenital defects, and increased risk for several diseases such as Alzheimer's disease and leukemia. Current DS-screening tests subject many women to invasive procedures for accurate diagnosis due to insufficient specificity. Since amniotic fluid (AF) surrounds the developing fetus, understanding the changes in AF composition in the presence of DS may provide insights into genotype-phenotype associations, and aid in discovery of novel biomarkers for better screening. On the basis of our previous study, in which we reported an extensive proteome of AF, we performed two-dimensional liquid chromatography followed by MS/MS to analyze triplicates of pooled AF of chromosomally normal and DS-affected pregnancies (10 samples per pool). A total of 542 proteins were identified from the two sets of triplicate analyses by the LTQ-Orbitrap mass spectrometer and data were compared semiquantitatively by spectral counting. Candidate biomarkers were selected based on the spectral count differences between the two conditions after normalization. Comparison between the two groups revealed 60 candidates that showed greater than 2-fold increase or decrease in concentration in the presence of DS. Among these candidates, amyloid precursor protein and tenascin-C were verified by ELISA, and both showed a 2-fold increase, on average, in DS-AF samples compared to controls. All proteins that showed significant differences between the two conditions were bioinformatically analyzed to preliminarily understand their biological implications in DS.
唐氏综合征（DS）是一种由额外的 21 号染色体引起的异常，每 750 例活产中就有 1 例。表型包括认知障碍、先天性缺陷和几种疾病的风险增加，如阿尔茨海默病和白血病。由于特异性不足，目前的 DS 筛查测试让许多女性接受侵入性程序以进行准确诊断。由于羊水（AF）环绕着发育中的胎儿，因此了解 DS 存在时 AF 成分的变化可能有助于深入了解基因型-表型关联，并有助于发现新的生物标志物以进行更好的筛查。基于我们之前的研究，我们报告了广泛的 AF 蛋白质组，我们进行了二维液相色谱法，然后进行 MS/MS 分析，以分析来自染色体正常和 DS 影响妊娠的羊水的三倍重复（每个池 10 个样本）。通过 LTQ-Orbitrap 质谱仪从两组三倍重复分析中鉴定出 542 种蛋白质，并通过光谱计数进行半定量比较。根据归一化后两种条件之间的光谱计数差异选择候选生物标志物。两组之间的比较显示，在存在 DS 的情况下，有 60 个候选物的浓度增加或减少超过 2 倍。在这些候选物中，淀粉样前体蛋白和 tenascin-C 通过 ELISA 验证，与对照组相比，DS-AF 样本的平均浓度增加了 2 倍。所有在两种条件之间显示显著差异的蛋白质都进行了生物信息学分析，以初步了解它们在 DS 中的生物学意义。
