Dataset Information

Global gene expression in response to X rays in mice deficient in Parp1

ABSTRACT: There is a current interest in the development of biodosimetric methods for rapidly assessing radiation exposure in the wake of a large-scale radiological event. The initial focus of this work has largely centered on determining the exposure dose to an individual using biological indicators. Gene expression signatures are showing promise for biodosimetric application, but little is known about how these signatures might translate for the assessment of radiological injury in radiosensitive individuals, who comprise a significant fraction of the general population, and who would likely require treatment following lower doses. Using Parp1-/- mice as a model radiation sensitive genotype, we have investigated the effect of this DNA repair deficiency on the gene expression response to radiation. Although Parp1 is known to play general roles in regulating transcription, the pattern of gene expression changes observed 24 h after exposure to a potentially lethal LD50 dose of radiation was remarkably similar in the two genotypes, and indicated similar levels of activation of both the p53 and NFκB radiation response pathways. In contrast, exposure of wild-type mice to a sub-lethal dose that was equal to the LD50 dose given to the Parp1-/- mice, resulted in a reduced gene expression response. Gene expression classifiers trained on the wild-type data correctly identified all wild-type samples as unexposed, exposed to a sub-lethal dose, or exposed to a potentially lethal dose. All unexposed samples from the Parp1-/- mice were also correctly classified, and 80% of the irradiated samples were identified as exposed to a potentially lethal dose. The results of this study suggest that, at least for some genotypes, gene expression has the potential to accurately detect the extent of radiological injury, rather than being useful only as a surrogate of physical radiation dose.

ORGANISM(S): Mus musculus

PROVIDER: GSE101402 | GEO | 2018/05/23

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Development of biomarkers capable of estimating absorbed dose is critical for effective triage of affected individuals after radiological events. Levels of cell-free circulating miRNAs in plasma were compared for dose-response analysis in non-human primates (NHP) exposed to lethal (6.5 Gy) and sub-lethal (1 and 3 Gy) doses over a 7 day period. The doses and test time points were selected to mimic triage needs in the event of a mass casualty radiological event. Changes in miRNA abundance in irradiated animals were compared to a non-irradiated cohort and a cohort experiencing acute inflammation response from exposure to lipopolysaccharide (LPS). An amplification-free, hybridization-based direct digital counting method was used for evaluation of changes in microRNAs in plasma from all animals. Consistent with previous murine studies, circulating levels of miR-150-5p exhibited a dose- and time-dependent decrease in plasma. Furthermore, plasma miR-150-5p levels were found to correlate well with lymphocyte and neutrophil depletion kinetics. Additionally, plasma levels of several other evolutionarily and functionally conserved miRNAs were found altered as a function of dose and time. Interestingly, miR-574-5p exhibited a distinct, dose-dependent increase 24 h post irradiation in NHPs with lethal versus sub-lethal exposure before returning to the baseline level by day 3. This particular miRNA response was not detected in previous murine studies but was observed in animals exposed to LPS, indicating distinct molecular and inflammatory responses. Furthermore, an increase in low-abundant miR-126, miR-144, and miR-21 as well as high-abundant miR-1-3p and miR-206 was observed in irradiated animals on day 3 and/or day 7. The data from this study could be used to develop a multi-marker panel with known tissue-specific origin that could be used for developing rapid assays for dose assessment and evaluation of radiation injury on multiple organs. Furthermore this approach may be utilized to screen for tissue toxicity in patients who receive myeloablative and therapeutic radiation.

Project description:Background: The effects of dose-rate and its implications on radiation biodosimetry methods are not well studied in the context of large-scale radiological scenarios. There are significant health risks to individuals exposed to an acute dose in such an event, but the most realistic scenario would be a combination of exposure to both high and low dose-rates, from both external and internal radioactivity. It is important therefore, to understand the biological response to prolonged exposure; and further, discover biomarkers that can be used to estimate the extent of damage from low-dose rate exposure and propose appropriate clinical treatment. Methods: We irradiated human whole blood ex vivo to three doses, 0.56 Gy, 2.25 Gy and 4.45 Gy, using two dose rates: 1.1Gy/min and 3.1mGy/min. After 24 hours, we isolated RNA from blood cells and hybridized these to Agilent Whole Human genome microarrays. We validated the microarray results using qRT-PCR. Results: Microarray results showed that there were 454 significantly differentially expressed genes after prolonged exposure to all doses. After acute exposure, 598 genes were differentially expressed to all doses combined. Gene ontology terms enriched in both sets of genes were related to immune processes and B cell mediated immunity. Genes responding to acute exposure was also enriched in functions related to natural killer cell activation and cell-to-cell signaling. As expected, p53 pathway was found to be significantly enriched at all doses and by both dose-rates of radiation. Prediction algorithms were able to distinguish between low dose-rate and acute exposures, on the basis of a group of genes. These maybe candidates for preliminary testing as markers for differences in gene expression based on dose-rate. Radiation induced gene expression was measured in ex vivo irradiated human blood, at the 24hr time point after irradiation. Doses (0.56 Gy, 2.2 Gy and 4.45 Gy) were delivered by two dose rates, acute dose rate of 1Gy/min and low dose rate of 3.1 mGy/min.

Dataset Information

Global gene expression in response to X rays in mice deficient in Parp1

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure