Project description:Low-dose radiation refers to exposure to ionizing radiation at levels that are generally considered safe and not expected to cause immediate health effects. However, the effects of low-dose radiation are still not fully understood and research in this area is ongoing. In this study, we investigated changes in gene expression in diabetic human aortic endothelial cells (T2D-HAECs) derived from type 2 diabetes patients. To this end, we used RNA-seq to profile the transcriptomes of cells exposed to varying doses of low-dose radiation (0.1Gy, 0.5Gy, and 2.0Gy) and compared them to a control group with no radiation exposure. Differentially expressed genes and enriched pathways were identified using the DESeq2 and gene set enrichment analysis (GSEA) methods, respectively. The data generated in this study are publicly available through the gene expression omnibus (GEO) database. This study provides a valuable resource for studying the effects of low-dose radiation on T2D-HAECs and can contribute to a better understanding of the potential human health risks associated with low-dose radiation exposure.
Project description:Assessment of the transcriptomics effects of chronic exposure to gamma ionizing radiation (IR) on zebrafish development at dose rates of 0.5mGy/h, 5mGy/h and 50mGy/h. Embryos were exposed chronically to IR from fertlization to developmental stages: 24hpf, 48hpf and 96hpf.
Project description:Human embryonic stem cells (hESCs) present a novel platform for in vitro investigation of the early embryonic cellular response to ionizing radiation. Thus far, no study has analyzed the genome-wide transcriptional response to ionizing radiation in hESCs. In this study, we use Agilent microarrays to analyze the global gene expression changes in H9 hESCs after low (0.4 Gy), medium (2 Gy), and high (4 Gy) dose irradiation.
Project description:This is a genome-wide approach to identifying genes persistently induced in the mouse mammary gland by acute whole body low dose ionizing radiation (10cGy), 1 and 4 weeks after exposure. Gene expression that is modified under these parameters were compared between Tgfb1 wild type and heterozygote littermates in order to determine which genes induced or repressed by radiation were mediated via Tgfb1 status. Differential gene expression was analyzed in Tgfb1 heterozygote and wild type littermate 4th mammary glands, after whole body exposure to an acute dose of 10cGy ionizing radiation. Estrus cycle was normalized in all mice two days prior to irradiation by injection with an estrogen and progesterone mixture. It is widely believed that the carcinogenic action of ionizing radiation is due to targeted DNA damage and resulting mutations, but there is also substantial evidence that non-targeted radiation effects alter epithelial phenotype and the stromal microenvironment. Activation of transforming growth factor beta 1 (TGFbeta) is a non-targeted radiation effect that mediates cell fate decisions following DNA damage and regulates microenvironment composition; it could either suppress or promote cancer. Gene expression profiling shown herein demonstrates that low dose radiation (10 cGy) elicits persistent changes in Tgfb1 wild type and heterozygote murine mammary gland that are highly modulated by TGFbeta. We asked if such non-targeted radiation effects contribute to carcinogenesis by using a novel radiation chimera model. Unirradiated Trp53 null mammary epithelium was transplanted to the mammary stroma of mice previously exposed to a single low (10 -100 cGy) radiation dose. By 300 days, 100% of transplants in irradiated hosts at either 10 or 100 cGy had developed Trp53 null breast carcinomas compared to 54% in unirradiated hosts. Tumor growth rate was also increased by high, but not low, dose host irradiation. In contrast, irradiation of Tgfb1 heterozygote mice prior to transplantation failed to decrease tumor latency, or increase growth rate at any dose. Host irradiation significantly reduced the latency of invasive ductal carcinoma compared to spindle cell carcinoma, as well as those tumors negative for smooth muscle actin in wild type but not Tgfb1 heterozygote mice. However, irradiation of either host genotype significantly increased the frequency of estrogen receptor negative tumors. These data demonstrate two concepts critical to understanding radiation risks. First, non-targeted radiation effects can significantly promote the frequency and alter the features of epithelial cancer. Second, radiation-induced TGFbeta activity is a key mechanism of tumor promotion. Keywords: Differential gene expression after low dose irradiation Two genotypes: TGBbeta1 heterozygote and wildtype mouse mammary glands. Two time points post-10cGy-irradiation per genotype (1 week, 4 weeks); control time point was 1 week post-sham-irradiation. Two or three replicates per time point.
Project description:Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but damage is repaired. We show that tardigrades have a specific and robust response to ionizing radiation: irradiation induces a rapid, dramatic upregulation of many DNA repair genes. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is necessary for tardigrade radiation tolerance. Tardigrades’ ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
Project description:Human embryonic stem cells (hESCs) present a novel platform for in vitro investigation of the early embryonic cellular response to ionizing radiation. Thus far, no study has analyzed the genome-wide transcriptional response to ionizing radiation in hESCs. In this study, we use Agilent microarrays to analyze the global gene expression changes in H9 hESCs after low (0.4 Gy), medium (2 Gy), and high (4 Gy) dose irradiation. Undifferentiated H9 hESCs were cultured on Matrigel in feeder-free conditions, and exposed to ionizing radiation at the indicated dosage (or control) from a Cesium-137 irradiator. Total RNA was isolated 24 hours after irradiation in the same feeder-free culture conditions. Experiment was repeated three times for each group, yielding a total of 12 distinct samples.
Project description:Ionizing radiation-induced changes to the redox balance does not only represent a risk for the cellular homeostasis, but can also induce a drastic modulation in the overall signalling system of cells. In the current study, effects of chronic exposure to ionizing gamma radiation were assessed in the radioresistant nematode Caenorhabditis elegans in order to understand whether antioxidant defences (AODs) could ameliorate radical formation, or if increased ROS levels would cause oxidative damage. This analysis was accompanied by phenotypical as well as molecular investigations, via assessment of reproductive capacity and somatic growth and differential gene expression through RNA sequencing. The use of a fluorescent reporter strain (sod1::gfp) and two ratiometric biosensors (Hyper and Grx1-roGFP2) demonstrated increased ROS production (H2O2) and activation of AODs (SOD1 and GPx) in vivo. The data indicate that at dose-rates ≤10 mGy/h defence mechanisms were able to prevent the manifestation of oxidative stress. In contrast, at dose-rates ≥40 mGy/h the constant formation of radicals induced a redox shift, which lead to oxidative damage responses, including changes in mitochondrial metabolism and functions, protein degradation, lipid metabolism, collagen synthesis and modulation of transcription. Moreover, genotoxic effects were among the most over-represented functions affected by chronic gamma irradiation, as indicated by differential regulation of genes involved in DNA damage, DNA repair, cell-cycle checkpoints, chromosome segregation and chromatin remodelling. Ultimately, the exposure to gamma radiation caused reprotoxic effects, with >20% reduction in the number of offspring per adult hermaphrodite at dose-rates ≥40 mGy/h, accompanied by the down-regulation of more than 300 genes related to reproductive system, meiotic functions and gamete development and fertilization.
Project description:The purpose of this study was to identify genes that were differentially expressed in radiation-sensitive, naïve HL60 cells, and the derivatives created in our laboratory as indicated in the 'sample title'. We wanted to identify genes that were differentially expressed both before and after ionizing radiation (IR) exposure, from both a single dose of gamma rays and a single dose of alpha particles, at 4h following IR exposure. The data were used to identify genes that could be driving radioresistance in each respective cell line. The four cell lines, HL60, RA11, RG8, and RV+ were all analyzed at control (0Gy) radiation dose, 8Gy gamma rays, and ~2Gy alpha particles. Samples were collected from each cell line, for each dose, 4h following radiation exposure. The samples were collected from three independent experiments from three consecutive days in cell culture.