Williams Sarah S, Mear John P, Liang Hung-Chi, Potter S Steven, Aronow Bruce J, Colbert Melissa C
Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Physiol Genomics. 2004 Oct 4;19(2):184-97. doi: 10.1152/physiolgenomics.00136.2004.
Although retinoic acid (RA), the active form of vitamin A, is required for normal embryonic growth and development, it is also a powerful teratogen. Infants born to mothers exposed to retinoids during pregnancy have a 25-fold increased risk for malformations, nearly exclusively of cranial neural crest-derived tissues. To characterize neural crest cell responses to RA, we exposed murine crest cultures to teratogenic levels of RA and subjected their RNA to microarray-based gene expression profile analysis using Affymetrix MG-U74Av2 GeneChips. RNAs were isolated from independent cultures treated with 10(-6) M RA for 6, 12, 24, or 48 h. Statistical analyses of gene expression profile data facilitated identification of the 205 top-ranked differentially regulated genes whose expression was reproducibly changed by RA over time. Cluster analyses of these genes across the independently treated sample series revealed distinctive kinetic patterns of altered gene expression. The largest group was transiently affected within the first 6 h of exposure, representing early responding genes. Group 2 showed sustained induction by RA over all times, whereas group 3 was characterized by the suppression of a time-dependent expression increase normally seen in untreated cells. Additional patterns demonstrated time-dependent increased or decreased expression among genes not normally regulated to a significant extent. Gene function analysis revealed that more than one-third of all RA-regulated genes were associated with developmental regulation, including both canonical and noncanonical Wnt signaling pathways. Multiple genes associated with cell adhesion and cell cycle regulation, recognized targets for the biological effects of RA, were also affected. Taken together, these results support the hypothesis that the teratogenic effects of RA derive from reprogramming gene expression of a host of genes, which play critical roles during embryonic development regulating pathways that determine subsequent differentiation of cranial neural crest cells.
尽管视黄酸（RA）作为维生素A的活性形式，是正常胚胎生长发育所必需的，但它也是一种强大的致畸剂。孕期接触过类视黄醇的母亲所生的婴儿出现畸形的风险增加了25倍，几乎全部集中在颅神经嵴衍生组织。为了表征神经嵴细胞对RA的反应，我们将小鼠嵴细胞培养物暴露于致畸水平的RA下，并使用Affymetrix MG-U74Av2基因芯片对其RNA进行基于微阵列的基因表达谱分析。RNA是从用10^(-6) M RA处理6、12、24或48小时的独立培养物中分离出来的。对基因表达谱数据的统计分析有助于识别205个排名靠前的差异调节基因，其表达随时间被RA可重复地改变。对这些基因在独立处理的样本系列中的聚类分析揭示了基因表达改变的独特动力学模式。最大的一组在暴露的前6小时内受到短暂影响，代表早期反应基因。第2组显示RA在所有时间都持续诱导，而第3组的特征是抑制了未处理细胞中通常所见的时间依赖性表达增加。其他模式显示在通常未受到显著调节的基因中表达随时间增加或减少。基因功能分析表明，所有受RA调节的基因中有超过三分之一与发育调节相关，包括经典和非经典Wnt信号通路。多个与细胞粘附和细胞周期调节相关的基因，即RA生物学效应的公认靶点，也受到了影响。综上所述，这些结果支持了这样一种假说，即RA的致畸作用源于大量基因的重新编程表达，这些基因在胚胎发育过程中调节决定颅神经嵴细胞后续分化的途径时发挥着关键作用。
