Untargeted metabolite profiling of murine embryos to reveal metabolic perturbations associated with neural tube closure defects

• Published in: Birth defects research. A Clinical and molecular teratology Vol. 100; no. 8; pp. 623 - 632
• Main Authors: Hansler, Alex, Chen, Qiuying, Gray, Jason D., Ross, M. Elizabeth, Finnell, Richard H., Gross, Steven S.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01-08-2014
• Subjects: Animals; closure defects; Disease Models, Animal; folate; Folic Acid - metabolism; Glutathione - metabolism; Low Density Lipoprotein Receptor-Related Protein-6 - genetics; Metabolome - genetics; Mice; Mice, Knockout; neural tube; Neural Tube - embryology; Neural Tube - metabolism; Neural Tube Defects - embryology; Neural Tube Defects - genetics; Neural Tube Defects - metabolism; Oxidation-Reduction; Oxidative Stress - genetics; Spinal Dysraphism - embryology; Spinal Dysraphism - genetics; closure defects; neural tube; folate
• ISSN: 1542-0752; 1542-0760
• DOI: 10.1002/bdra.23272

Background
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.
Methods
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
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.
Conclusion
Whole‐embryo metabolomics offers the potential to identify metabolic changes in genetically determined NTD‐prone embryos. Birth Defects Research (Part A) 100:623–632, 2014. © 2014 Wiley Periodicals, Inc.