Acute and long-term responses to radiation in zebrafish
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ABSTRACT: A set of changes is identified in the transcription profile associated with the long-term, but not the acute, response to radiation exposure. The study was performed in vivo using zebrafish. To study the long-term response, 24 hour post-fertilization embryos were exposed to 0.1 Gy (low dose) or 1.0 Gy (moderate dose) of whole-body gamma radiation and allowed to develop for 16 weeks. Liver mRNA profiles were then analyzed using the Affymetrix microarray platform, with validation by quantitative PCR. To be able to compare this to the acute response, 16-week old adults were exposed at the same doses and analyzed after 4 hours.
Project description:A set of changes is identified in the transcription profile associated with the long-term, but not the acute, response to radiation exposure. The study was performed in vivo using zebrafish. To study the long-term response, 24 hour post-fertilization embryos were exposed to 0.1 Gy (low dose) or 1.0 Gy (moderate dose) of whole-body gamma radiation and allowed to develop for 16 weeks. Liver mRNA profiles were then analyzed using the Affymetrix microarray platform, with validation by quantitative PCR. To be able to compare this to the acute response, 16-week old adults were exposed at the same doses and analyzed after 4 hours. We used 5 treatment groups: A=non-irradiated control, allowed to develop for 16 weeks; B=low-dose (0.1 Gy) irradiated, allowed to develop for 16 weeks; C=high-dose (1.0 Gy) irradiate, allowed to develop for 16 weeks; D=16 week old adults irradiated at low dose (0.1 Gy); E=16 week old adults irradiate at high dose (1.0 Gy)
Project description:The biomedical consequences of space radiation pose a significant concern for astronauts engaged in deep space. However, the effects of long-term low dose-rate exposures in space environments remain elusive. In this study, we simulated the space radiation environment by exposing human bronchial epithelial cells to low dose-rate (0.0067 Gy/day) α-particles, and continuously irradiated them multiple times to achieve cumulative total doses of 0.2 Gy, 0.4 Gy, and 0.5 Gy, respectively. At the same time, the cells were irradiated with the same total dose in a single exposure to investigate the potential of low dose-rate alpha particles to induce malignant transformation of human bronchial epithelial cells. A comprehensive suite of assays was employed to assess tumorigenic potential, including tumor formation in NOD/SCID mice, immunohistochemistry, CCK-8 proliferation assay, invasion assay, and the evaluation of multicellular spheroid formation during subsequent passages post-irradiation. Moreover, we dissected differential malignant mechanisms in tumor evolution ecosystem induced by the two distinct irradiation modes from systems biology views based on scRNA-seq technology. Our results showed that exposure to α-particles, whether through a single acute exposure or long-term low dose-rate exposures, induced the occurrence and development of tumors. Long-term low dose-rate exposures to α-particles increase the malignancy of induced tumors, but not the risk of carcinogenesis, compared to a single acute exposure with the same total dose. In addition, through scRNA-seq, we found that long-term low dose-rate exposures triggered more copy number variation (CNV) and epithelial-mesenchymal transition (EMT) events, and the activation of DNA damage repair pathways occurred significantly later than with a single acute exposure and involved more specific changes in cellular communication dynamics. In conclusion, our findings provide emerging yet convincing evidence that not only sheds light on why cells exposed to long-term low dose-rate exposures exhibit heightened malignancy, but also offers valuable insights into the genetic determinants driving tumor evolution and heterogeneity.
Project description:Expression profiles in mouse liver exposed to long-term gamma-irradiation were examined to assess in vivo effects of low dose-rate radiation. Three groups of male C57BL/6J mice were exposed to whole body irradiation at dose-rates of 17-20 mGy/day, 0.86-1.0 mGy/day or 0.042-0.050 mGy/day for 401-485 days (cumulative doses were approximately 8 Gy, 0.4 Gy or 0.02 Gy, respectively). Expression profiles were produced for RNA isolated from irradiated individual animals and for pooled RNA from sham-irradiated 3 animals for control. The expression levels of 6 irradiated animals for each dose were compared individually with those of 2 pooled controls (3 irradiated samples to one pooled control in first and second experiments).
Project description:The endothelium is the barrier separating blood and tissue. Radiation-induced enhanced inflammation leading to permeability of this barrier may increase the risk of cardiovascular disease. The aim of this study was to investigate the onset of endothelial inflammatory pathways after radiation exposure. Human coronary artery endothelial cells (HCECest2) were exposed to radiation doses of 0, 0.25, 0.5, 2.0 and 10 Gy (60Co-γ). The cells were harvested 4 h, 24 h, 48 h and 1 wk post-irradiation. The proteomics analysis was performed in a label-free data-independent acquisition mode. The data were validated using bioinformatics and immunoblotting. The low- and moderate-dose-treated samples showed only small proteome changes. In contrast, an activation of DNA-damage repair, inflammation, and oxidative stress pathways was seen after high-dose treatments (2 and 10 Gy). The level of the DNA damage response protein DDB2 was enhanced early at the 10 Gy dose. The expression of proteins belonging to the inflammatory response or cGAS-STING pathway (STING, STAT1, ICAM1, ISG15) increased in a dose-dependent manner showing the strongest effects at 10 Gy after one week. This study suggests a connection between radiation-induced DNA damage and induction of inflammation and supports inhibition of cGAS-STING pathway in the prevention of radiation-induced cardiovascular disease.
Project description:Background and Purpose: Cardiotoxicity is a well-known adverse effect of radiation therapy. Measurable abnormalities in the heart function indicate advanced and often irreversible heart damage. Therefore, early detection of cardiac toxicity is necessary to delay and alleviate the development of the disease. The present study investigated long-term serum proteome alterations following local heart irradiation using a mouse model with the aim to detect biomarkers of radiation-induced cardiac toxicity. Materials and Methods: Serum samples from C57BL/6J mice were collected 20 weeks after local heart irradiation with 8 Gy or 16 Gy X-ray; the controls were sham-irradiated. The samples were analyzed by quantitative proteomics based on data-independent acquisition mass spectrometry. The proteomics data were further investigated using bioinformatics and ELISA. Results: The analysis showed radiation-induced changes in the level of several serum proteins involved in the acute phase response, inflammation and cholesterol metabolism. We found significantly enhanced expression of pro-inflammatory cytokines (TNF-, TGF-, IL-1 and IL-6) in the serum of the irradiated mice. The level of free fatty acids, total cholesterol, low density lipoprotein (LDL) and oxidized LDL was increased whereas that of high density lipoprotein was decreased by irradiation. Conclusions: This study provides information on systemic effects of heart irradiation. It elucidates a radiation fingerprint in the serum that may be used to elucidate adverse cardiac effects after radiation therapy.
Project description:Radiation biodosimetry can play a critical role in the response to a large-scale radiologic emergency, and gene expression profiles have shown promise for providing biodosimetric information. This study was designed to test if gene expression could be used to distinguish between doses received from acute exposures and more protracted exposures, such as those that would result from fallout. Mice were exposed to whole body X-rays at low dose rate (LDR, 3.09 mGy/min) for 6, 12, or 24 hours (1.1, 2.2, or 4.4 Gy), or to equivalent doses delivered at high dose rate (HDR, 1.03 Gy/min). Global gene expression was measured in their blood 24 h after the start of exposure, and genes with the potential to classify samples by radiation dose and dose rate were identified. Data consist of 48 samples, representing 6 independent samples each from 3 doses delivered as either acute or low dose rate x-rays, plus 12 controls representing both acute and low dose rate sham treatments.
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.
Project description:Radiation biodosimetry can play a critical role in the response to a large-scale radiologic emergency, and gene expression profiles have shown promise for providing biodosimetric information. This study was designed to test if gene expression could be used to distinguish between doses received from acute exposures and more protracted exposures, such as those that would result from fallout. Mice were exposed to whole body X-rays at low dose rate (LDR, 3.09 mGy/min) for 6, 12, or 24 hours (1.1, 2.2, or 4.4 Gy), or to equivalent doses delivered at high dose rate (HDR, 1.03 Gy/min). Global gene expression was measured in their blood 24 h after the start of exposure, and genes with the potential to classify samples by radiation dose and dose rate were identified.
Project description:One of the most likely risks astronauts on long duration space missions face is exposure to ionizing radiation associated with highly energetic and charged heavy (HZE) particles. Since access to medical expertise on such a mission is limited at best, early diagnosis and mitigation of such exposure is critical. In order to accurately determine the dosage within 1 hour post-exposure, dose-dependent âbiomarkersâ are needed. Therefore, we performed a dose-course transcriptional analysis for radiation exposure at 0, 0.3, 1.5, and 3.0 Gy with corresponding time point at 1 hour (hr) post-exposure using Affymetrix® GeneChip® Human Gene 1.0 ST v1 Array chips. The analysis of our data suggests a set of sensitive genetic biomarkers specific to each radiation level as well as generic radiation response biomarkers. Upregulated biomarkers can then be used within lab-on-a-chip (LOC) systems to detect exposure to ionizing radiation. A total of sixteen human samples representing radiation exposure at levels 0 Gy, 0.3 Gy, 1.5 Gy and 3.0 Gy at time point 1 hour (hr) post-exposure were constructed. Blood samples were extracted from four human volunteers, and were irradiated. Leukocytes were extracted, and gene expression was measured. Samples for all four volunteers were measured at 1 hr for all four dose levels, resulting in four replicates at each dose level. Thus, a total of 4 samples at each of the four radiation levels were sampled, yielding the total of 16 samples.
Project description:Acute exposure to high-dose gamma radiation often results in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip device consisting of human lung alveolar epithelium and pulmonary endothelium (Lung Alveolus Chip) is used to recapitulate acute, early stage RILI in vitro. This RNA-seq data captures that both the lung epithelium and endothelium in this model capture key hallmarks of this disease particularly, DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6h of radiation exposure. The data also suggests that radiation affects the alveolar endothelium more significantly than the epithelium. The alveolus chips are exposed to radiation injury at 16 Gy and shows effects that resemble the human lung greater than animal preclinical models. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative approach for studying the molecular basis of acute RILI towards screening radiation countermeasure therapeutics.