Dataset for dose and time-dependent transcriptional response to ionizing radiation exposure

Postsynaptic density radiation signature following space irradiation

Introduction: The response of the brain to space radiation is an important concern for astronauts during space missions. Therefore, we assessed the response of the brain to ²⁸Si ion irradiation (600 MeV/n), a heavy ion present in the space environment, on cognitive performance and whether the response is associated with altered DNA methylation in the hippocampus, a brain area important for cognitive performance. Methods: We determined the effects of ²⁸Si ion irradiation on object recognition, 6-month-old mice irradiated with ²⁸Si ions (600 MeV/n, 0.3, 0.6, and 0.9 Gy) and cognitively tested two weeks later. In addition, we determined if those effects were associated with alterations in hippocampal networks and/or hippocampal DNA methylation. Results: At 0.3 Gy, but not at 0.6 Gy or 0.9 Gy, ²⁸Si ion irradiation impaired cognition that correlated with altered gene expression and 5 hmC profiles that mapped to specific gene ontology pathways. Comparing hippocampal DNA hydroxymethylation following proton, ⁵⁶Fe ion, and ²⁸Si ion irradiation revealed a general space radiation synaptic signature with 45 genes that are associated with profound phenotypes. The most significant categories were glutamatergic synapse and postsynaptic density. Discussion: The brain's response to space irradiation involves novel excitatory synapse and postsynaptic remodeling.

Clinical Trial in a Dish for Space Radiation Countermeasure Discovery

NASA aims to return humans to the moon within the next five years and to land humans on Mars in a few decades. Space radiation exposure represents a major challenge to astronauts' health during long-duration missions, as it is linked to increased risks of cancer, cardiovascular dysfunctions, central nervous system (CNS) impairment, and other negative outcomes. Characterization of radiation health effects and developing corresponding countermeasures are high priorities for the preparation of long duration space travel. Due to limitations of animal and cell models, the development of novel physiologically relevant radiation models is needed to better predict these individual risks and bridge gaps between preclinical testing and clinical trials in drug development. "Clinical Trial in a Dish" (CTiD) is now possible with the use of human induced pluripotent stem cells (hiPSCs), offering a powerful tool for drug safety or efficacy testing using patient-specific cell models. Here we review the development and applications of CTiD for space radiation biology and countermeasure studies, focusing on progress made in the past decade.

The Effect of Contrast Enhanced Abdominopelvic Magnetic Resonance Imaging on Expression and Methylation Level of ATM and AKT Genes

Objective

To evaluate the effect of contrast enhanced abdominopelvic magnetic resonance imaging (MRI), using a 3 Tesla scanner, on expression and methylation level of ATM and AKT genes in human peripheral blood lymphocytes.

Materials and Methods

In this prospective in vivo study, blood samples were obtained from 20 volunteer patients with mean age of 43 ± 8 years (range 32-68 years) before contrast enhanced MRI, 2 hours and 24 hours after contrast enhanced abdominopelvic 3 Tesla MRI. After separation of mononuclear cells from peripheral blood, using Ficoll-Hypaque, we analyzed gene expression changes of ATM and AKT genes 2 hours and 24 hours after MRI using quantitative reverse transcription polymerase chain reaction (qRT-PCR). We also evaluated methylation percentage of the above mentioned genes in before, 2 hours and 24 hours after MRI, using MethySYBR method.

Results

Fold change analysis, in comparison with the baseline, respectively showed 1.1 ± 0.7 and 0.8 ± 0.5 mean of gene expressions in 2 and 24 hours after MRI for ATM, while the results were 1.4 ± 0.6 and 1.4 ± 1 for AKT (P>0.05). Methylation of the ATM gene promoter were 8.8 ± 1.5%, 9 ± 0.6% and 9 ± 0.8% in before contrast enhanced MRI, 2 and 24 hours after contrast enhanced MRI, respectively (P>0.05). Methylation of AKT gene promoter in before contrast enhanced MRI, 2 hours and 24 hours after contrast enhanced MRI was 5.4 ± 2.5, 5 ± 3.2, 4.9 ± 2.9 respectively (P>0.05).

Conclusion

Contrast enhanced abdominopelvic MRI using 3 Tesla scanner apparently has no negative effect on the expression and promoter methylation level of ATM and AKT genes involved in the repair pathways of genome.

A Meta-Analysis of the Effects of High-LET Ionizing Radiations in Human Gene Expression

The use of high linear energy transfer (LET) ionizing radiation (IR) is progressively being incorporated in radiation therapy due to its precise dose localization and high relative biological effectiveness. At the same time, these benefits of particle radiation become a high risk for astronauts in the case of inevitable cosmic radiation exposure. Nonetheless, DNA Damage Response (DDR) activated via complex DNA damage in healthy tissue, occurring from such types of radiation, may be instrumental in the induction of various chronic and late effects. An approach to elucidating the possible underlying mechanisms is studying alterations in gene expression. To this end, we identified differentially expressed genes (DEGs) in high Z and high energy (HZE) particle-, γ-ray- and X-ray-exposed healthy human tissues, utilizing microarray data available in public repositories. Differential gene expression analysis (DGEA) was conducted using the R programming language. Consequently, four separate meta-analyses were conducted, after DEG lists were grouped depending on radiation type, radiation dose and time of collection post-irradiation. To highlight the biological background of each meta-analysis group, functional enrichment analysis and biological network construction were conducted. For HZE particle exposure at 8–24 h post-irradiation, the most interesting finding is the variety of DNA repair mechanisms that were downregulated, a fact that is probably correlated with complex DNA damage formation. Simultaneously, after X-ray exposure during the same hours after irradiation, DNA repair mechanisms continue to take place. Finally, in a further comparison of low- and high-LET radiation effects, the most prominent result is that autophagy mechanisms seem to persist and that adaptive immune induction seems to be present. Such bioinformatics approaches may aid in obtaining an overview of the cellular response to high-LET particles. Understanding these response mechanisms can consequently aid in the development of countermeasures for future space missions and ameliorate heavy ion treatments.