A lipidomic and metabolomic serum signature from nonhuman primates exposed to ionizing radiation

Abstract

Introduction Due to dangers associated with potential accidents from nuclear energy and terrorist threats, there is a need for high-throughput biodosimetry to rapidly assess individual doses of radiation exposure. Lipidomics and metabolomics are becoming common tools for determining global signatures after disease or other physical insult and provide a “snapshot” of potential cellular damage. Objectives The current study assesses changes in the nonhuman primate (NHP) serum lipidome and metabolome 7 days following exposure to ionizing radiation (IR). Methods Serum sample lipids and metabolites were extracted using a biphasic liquid-liquid extraction and analyzed by ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry. Global radiation signatures were acquired in data-independent mode. Results Radiation exposure caused significant perturbations in lipid metabolism, affecting all major lipid species, including free fatty acids, glycerolipids, glycerophospholipids and esterified sterols. In particular, we observed a significant increase in the levels of polyunsaturated fatty acids (PUFA)-containing lipids in the serum of NHPs exposed to 10 Gy radiation, suggesting a primary role played by PUFAs in the physiological response to IR. Metabolomics profiling indicated an increase in the levels of amino acids, carnitine, and purine metabolites in the serum of NHPs exposed to 10 Gy radiation, suggesting perturbations to protein digestion/absorption, biological oxidations, and fatty acid β-oxidation. Conclusions This is the first report to determine changes in the global NHP serum lipidome and metabolome following radiation exposure and provides information for developing metabolomic biomarker panels in human-based biodosimetry.

Metabolic Dysregulation after Neutron Exposures Expected from an Improvised Nuclear Device

“…Sphinganine-1-phosphate was purchased from Avanti ® Polar Lipids, Inc. (Alabaster, AL), N-decanoyglycine from Hit2Lead (San Diego, CA) and decanoylcarnitine from Tocris Bioscience (Bristol, UK). Standards for lipidomics have been previously described elsewhere (9, 28) and covered all broad lipid classes.…”

“…Both serum and urine samples were centrifuged for 20 min (4°C maximum speed). For serum lipidomic analysis, samples were prepared with chloroform:methanol (2:1) with the appropriate lipidomic internal standards (28) (25 μ l of serum used). Two microliters of each sample were injected in a Waters ® Acquity Ultra Performance Liquid Chromatography (UPLC ® ) system, coupled to a Waters Xevo ® G2 QTOF-MS (Waters, Milford MA).…”

“…Serum metabolomic and lipidomic preprocessing was performed with Progenesis QI (Nonlinear Dynamics, Newcastle, UK). Normalization was performed with the option, “normalize to all compounds”, utilized in previously published studies (15, 28, 29) to minimize the influence of outliers and create a normal distribution of the data. Deconvoluted data consisted of a matrix with normalized abundance levels for each ion of each sample, where each ion was identified by a unique set of mass over charge ratios ( m / z ) and retention time.…”

Gas Chromatography/Mass Spectrometry Metabolomics of Urine and Serum from Nonhuman Primates Exposed to Ionizing Radiation: Impacts on the Tricarboxylic Acid Cycle and Protein Metabolism

“…10,16,17 Urine and serum were collected on day 7, stored at −70 °C, and shipped on dry ice to Georgetown University Medical Center. Urine was collected by cystocentesis for the treatment group and overnight for the control group.…”

“…As previously mentioned, 16 7 day biomarkers are needed because individuals may need extended time for sample processing due to ensuing alarm and panic following potential mass radiation exposures. Additionally, NHP systems have the advantage of (1) clinical signs and mitigator effects from IR exposure being well documented, 28–31 (2) continually expanding knowledge on metabolomic signatures from IR exposure, 9,10,13,16,17,32,33 and (3) genetically closer to human studies than murine models. 18 We found several small carboxylic acids, amino acids, and tricarboxylic acid (TCA) cycle intermediates not previously identified by targeted and global metabolomic studies performed on LC–MS platforms.…”