Project description:The purpose of this study was to identify genes that are modulated by alpha particle radiation Cell types were independently exposed to alpha particle radiation using Americium-241 discs (0.9Gy/hr) at a dose range from 0-1.5 Gy. Twenty-four hours post-exposure cells were harvested and RNA was extracted and subjected to microarray analysis.
Project description:Abstract Purpose: There is a recognised need to develop new methods of high throughput, rapid and minimally invasive individual dose assessment for radiation exposure. The aim of this work is to establish a panel of highly radiation responsive genes suitable for biological dosimetry and to explore inter-individual variation in response to ionising radiation exposure.Materials and method: Analysis of gene expression in response to radiation was carried out using three independent techniques (microarray, Multiplex Quantitative RT-PCR and nCounter Analysis System) in human lymphocytes in culture and circulating blood exposed ex vivo from the same donors. Results: Variations in transcriptional response to exposure to ionising radiation analysed by microarray allowed the identification of genes which can be validated and measured accurately as biomarkers of radiation exposure using other techniques. We have identified genes which are consistently up-regulated following exposure at different time points to either 2 or 4 Gy of X-rays, for all individuals in blood and cultured lymphocytes. Most down-regulated genes including cyclins, centromeric and mitotic checkpoints proteins, particularly those associated with chromosome instability and cancer can only be detected in dividing cells. Conclusions: The data provides evidence that there are a number of genes which seem suitable for biological dosimetry, like SESN1, GADD45A, CDKN1A, CCNG1, FDXR, BBC3 and MDM2. ÊThese biomarkers could potentially be used for triage after large-scale radiological incidents. Variations in transcriptional response accurately measured by MQRT-PCRæ may allow the identification of biomarkers of radiation sensitivity and individual susceptibility and therefore being useful in radiation oncology.
Project description:After defining a gene expression signature that predicted radiation exposure dose with high accuracy in human peripheral white blood cells irradiated ex vivo, we now demonstrate the predictive power of gene expression signatures in blood from patients undergoing total body irradiation. Using whole genome microarray analysis, we have identified genes that respond to radiation exposure in cancer patients in vivo. A 3-nearest neighbor classifier built from these genes correctly predicted samples as exposed to 0, 1.25 or 3.75 Gy with 94% accuracy even when samples from healthy donor controls were included. The same samples were classified with 98% accuracy using a signature previously defined from ex vivo irradiation data. The samples could also be classified as exposed or not exposed with 100% accuracy using multiple methods. The demonstration that ex vivo irradiation is an appropriate model that can provide meaningful prediction of in vivo exposure, and that the signatures are robust across diverse disease states, is an important advance in the application of gene expression for biodosimetry. Translation of these signatures to a fully automated “lab-on-a-chip” device will enable high-throughput screening for large-scale radiological emergencies, as well as making such tests practical for clinical uses. Radiation induced gene expression was measured in vivo in TBI patients at 4 hours after 1.25Gy exposure or at 24 hours after 3.75Gy exposure with three 1.25Gy split doses (approximately 4 hours apart). A total of 18 TBI patients, diagnosed with a variety of cancers were used in this study. Blood from 14 healthy control individuals was also used for comparison.
Project description:Four human-derived cell types: transformed monocytes (THP-1), transformed lung epithelial cells (A549), normal human pulmonary endothelial cells (HPEAC) and normal lung fibroblasts (HFL-1) Cell types were independently exposed to alpha particle radiation using Americium-241 discs (0.9Gy/hr) at a dose range from 0-1.5 Gy. Twenty-four hours post-exposure cells were harvested and RNA was extracted and subjected to microarray analysis.
Project description:CD8+ cytotoxic T lymphocytes (CTLs) play a major role in defense against intracellular pathogens, and their functions are specified by antigen recognition and innate cytokines. While effector CTLs eliminate the infection, a small population of memory cells are retained that yields more rapid and robust response upon re-infection. Antigen presenting cells secrete an array of innate cytokines including IL-12 and IFN-α after recognition of pathogens. Both IL-12 and IFN-α have been shown to act as the third signal regulating the development of CTLs. We have shown that these two cytokines have a non-redundant effect in generation of human effector CTL. IL-12 alone is sufficient for effector CTL genesis marked by IFN-γ and TNF-α production, as well as increased cytolytic activity. Even in the presence of IFN-α, IL-12 programs CTLs that express the chemokine receptor CXCR3 and effector cytokines. Using microarray analysis we have investigated how IL-12 and IFN-α differentially regulate the genetic programming pathways that give rise to effector CTLs among multiple human donors. We have also analyzed the gene expression patterns of cells sorted from healthy human peripheral blood that display surface markers of effector memory CTL (designated as ex vivo) samples. 5 healthy human donor samples were used for the in vitro cultures. For each donor the CFSE labeled cells (CD8+CD45RA+) were cultured in the presence of neutralized, IL-12, IFN-a, and IL-12+IFN-a conditions and plate-bound anti-CD3+anti-CD28 for 3.5 days. Total RNA from CFSEhi (Undiv) and CFSElo (Div) sorted cells were used for Illumina Bead Array. 4 healthy human donor samples were used for the ex vivo samples. Total RNA was collected from FACS sorted CD8+CCR7hiCXCR3lo and CD8+CCR7loCXCR3hi cells without any stimulation.
Project description:After defining a gene expression signature that predicted radiation exposure dose with high accuracy in human peripheral white blood cells irradiated ex vivo, we now demonstrate the predictive power of gene expression signatures in blood from patients undergoing total body irradiation. Using whole genome microarray analysis, we have identified genes that respond to radiation exposure in cancer patients in vivo. A 3-nearest neighbor classifier built from these genes correctly predicted samples as exposed to 0, 1.25 or 3.75 Gy with 94% accuracy even when samples from healthy donor controls were included. The same samples were classified with 98% accuracy using a signature previously defined from ex vivo irradiation data. The samples could also be classified as exposed or not exposed with 100% accuracy using multiple methods. The demonstration that ex vivo irradiation is an appropriate model that can provide meaningful prediction of in vivo exposure, and that the signatures are robust across diverse disease states, is an important advance in the application of gene expression for biodosimetry. Translation of these signatures to a fully automated “lab-on-a-chip” device will enable high-throughput screening for large-scale radiological emergencies, as well as making such tests practical for clinical uses.
Project description:Understanding the possible impact of potential confounding factors is necessary for any approach to radiation biodosimetry. Potential confounding factors have not been fully addressed for gene expression-based biodosimetry approaches, such as we are developing. To begin addressing this need, we have used an ex vivo irradiated peripheral blood cell model to investigate the potential effect of smoking on the global radiation gene expression response, and looked for genes that respond to radiation differently in smokers and non-smokers, and also in males and females. The results indicate that only a small number of genes may be significantly confounded by either factor, supporting the idea of developing peripheral blood gene expression strategies for radiation biodosimetry. Blood from each of 24 different donors was exposed to four doses of ionizing radiation (0, 0.1, 0.5, or 2 Gy) and analyzed using single-color microarray hybridization. The donors represented equal numbers of male and female smokers (1 or more packs a day) and non-smokers. There are 95 data sets in the study as the sample from one of the female smokers exposed to 2 Gy was lost.
Project description:Analysis of human peripheral blood 48 hours after irradiation ex vivo with graded doses of gamma rays. Results have been used in building and testing classifiers to predict exposure dose for use in radiological triage, and also provide insight into immune cell responses. Results were compared with those from earlier times and from patients exposed in vivo. Peripheral blood from 5 healthy donors was exposed ex vivo to 0. 0.5, 2, 5, or 8 Gy gamma-rays and gene expression was analyzed up to 48 hours after exposure.
Project description:To further development of our gene expression approach to biodosimetry, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to distinguish radiation dose across an exposure range relevant for medical decision-making in a radiological emergency. Human peripheral blood from healthy donors was irradiated ex vivo, and a 74-gene consensus signature was identified that distinguished between four radiation doses (0.5, 2, 5 and 8 Gy) and control samples. The same set of genes separated samples by exposure level at both six and 24 hours after treatment, with overlap evident only at the highest two doses (5 and 8 Gy). Expression of five genes (CDKN1A, FDXR, SESN1, BBC3 and PHPT1) from this signature was quantified in the same RNA samples by real-time PCR, confirming low variability between donors as well as the predicted radiation response pattern. Keywords: Dose Response, stress response, radiation response, biodosimetry