High-performance metabolic profiling with dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) for study of the exposome

Abstract

Studies of gene–environment (G × E) interactions require effective characterization of all environmental exposures from conception to death, termed the exposome. The exposome includes environmental exposures that impact health. Improved metabolic profiling methods are needed to characterize these exposures for use in personalized medicine. In the present study, we compared the analytic capability of dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) to previously used liquid chromatography-FTMS (LC-FTMS) analysis for high-throughput, top-down metabolic profiling. For DC-FTMS, we combined data from sequential LC-FTMS analyses using reverse phase (C18) chromatography and anion exchange (AE) chromatography. Each analysis was performed with electrospray ionization in the positive ion mode and detection from m/z 85 to 850. Run time for each column was 10 min with gradient elution; 10 µl extracts of plasma from humans and common marmosets were used for analysis. In comparison to analysis with the AE column alone, addition of the second LC-FTMS analysis with the C18 column increased m/z feature detection by 23–36%, yielding a total number of features up to 7,000 for individual samples. Approximately 50% of the m/z matched to known chemicals in metabolomic databases, and 23% of the m/z were common to analyses on both columns. Database matches included insecticides, herbicides, flame retardants, and plasticizers. Modularity clustering algorithms applied to MS-data showed the ability to detection clusters and ion interactions. DC-FTMS thus provides improved capability for high-performance metabolic profiling of the exposome and development of personalized medicine.

Short-term oral atrazine exposure alters the plasma metabolome of male C57BL/6 mice and disrupts α-linolenate, tryptophan, tyrosine and other major metabolic pathways

“…The samples were prepared as described by Soltow et al (2013). Briefly, each plasma aliquot (50 μL) was spiked with a 2.5-μL internal standard mix consisting of 14 stable isotopic chemicals that represent a broad range of chemical properties of small molecules prior to extraction.…”

“…The LC-MS analysis was done as in Soltow et al (2013). Briefly, extracts were loaded onto a Shimadzu (Sil-20AC Prominence) autosampler and maintained at 4 0 C until injection.…”

“…Data collection and extraction procedure was according to Soltow et al (2013). Feature tables containing m/z features, retention time, and integrated ion intensities were generated using the apLCMS software package (Yu et al 2009).…”

“…The advantage of this approach is that it allows rapid detection of both global changes of all metabolites or specific metabolites' changes following exposure to xenobiotics using small amounts of easily accessible biological samples, such as blood or urine (Soltow et al 2013). These altered metabolites can serve as biomarkers of toxicants' effects and can also be mapped to known biochemical pathways, thereby helping elucidate mechanisms of toxicity.…”

“…Recently, we established a "top-down" method of metabolic profiling using dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) that provided improved metabolic profiling capability compared to previous platforms (Soltow et al 2013). Taking advantage of this new method and considering the absence of data on biomarkers of ATR's effects in mammals, the objective of this study was to determine the effects of short-term ATR exposure, which we have already demonstrated to cause adverse behavioral and neurochemical effects (Lin et al 2013a), on the mouse plasma metabolome.…”