Hansler Alex, Chen Qiuying, Gray Jason D, Ross M Elizabeth, Finnell Richard H, Gross Steven S
Department of Pharmacology, Weill Cornell Medical College, New York, New York; Program in Pharmacology, Weill Cornell Medical College, New York, New York.
Birth Defects Res A Clin Mol Teratol. 2014 Aug;100(8):623-32. doi: 10.1002/bdra.23272. Epub 2014 Aug 13.
Neural tube closure defects (NTDs) are among the most common congenital malformation in human, typically presenting in liveborns as spina bifida. At least 240 gene mutations in mouse are known to increase the risk of NTD. There is a growing appreciation that environmental factors significantly contribute to NTD expression, and that NTDs likely arise from complex gene-environment interactions. Because maternal folic acid supplementation reduces human NTD risk in some populations by 60 to 70%, it is likely that NTD predisposition is often associated with a defect in folate-dependent one-carbon metabolism. A comprehensive, untargeted metabolic survey of NTD-associated changes in embryo metabolism would provide a valuable test of this assumption. We sought to establish a metabolic profiling platform that is capable of broadly assessing metabolic aberrations associated with NTD-promoting gene mutations in early-stage mouse embryos.
A liquid chromatography/mass spectrometry-based untargeted metabolite profiling platform was used to broadly identify significant differences in small molecule levels (50-1000 Da) in NTD-affected embryonic day (E) 9.5 mouse embryos (Lrp6(-) (/) (-) ) versus unaffected (Lrp6(+/+) ) control embryos.
Results provide proof-of-principal feasibility for the broad survey of the metabolome of individual E9.5 mouse embryos and identification of metabolic changes associated with NTDs and gene mutations. Levels of 30 different metabolites were altered in association with Lrp6 gene deletion. Some metabolites link to folate-dependent one-carbon transfer reactions, as anticipated, while others await structure elucidation and pathway integration.
Whole-embryo metabolomics offers the potential to identify metabolic changes in genetically determined NTD-prone embryos.
神经管闭合缺陷（NTDs）是人类最常见的先天性畸形之一，通常在活产儿中表现为脊柱裂。已知小鼠中至少有240种基因突变会增加患NTD的风险。人们越来越认识到环境因素对NTD的表达有显著影响，而且NTDs可能源于复杂的基因-环境相互作用。由于孕妇补充叶酸可使某些人群的人类NTD风险降低60%至70%，因此NTD易感性可能常与叶酸依赖性一碳代谢缺陷有关。对与NTD相关的胚胎代谢变化进行全面、非靶向的代谢调查将为这一假设提供有价值的检验。我们试图建立一个代谢谱分析平台，能够广泛评估与早期小鼠胚胎中促进NTD的基因突变相关的代谢异常。
使用基于液相色谱/质谱的非靶向代谢物谱分析平台，广泛鉴定受NTD影响的胚胎第9.5天（E）小鼠胚胎（Lrp6(- / -)）与未受影响的（Lrp6(+/+)）对照胚胎中小分子水平（50-1000 Da）的显著差异。
结果为广泛调查单个E9.5小鼠胚胎的代谢组以及鉴定与NTDs和基因突变相关的代谢变化提供了原理验证的可行性。与Lrp6基因缺失相关的30种不同代谢物的水平发生了改变。一些代谢物如预期的那样与叶酸依赖性一碳转移反应相关，而其他代谢物则有待结构解析和途径整合。
全胚胎代谢组学有潜力识别基因决定的NTD易患胚胎中的代谢变化。
