Comparison of Novel Proteomic Expression Profiles for Radiation Exposure in Male and Female C57BL6 Mice.

There is a need for point-of-care diagnostics for future mass casualty events involving radiation exposure. The development of radiation exposure and dose prediction algorithms for biodosimetry is needed for screening of large populations during these scenarios, and exploration of the potential effects which sex, age, genetic heterogeneity, and physiological comorbidities may have on the utility of biodosimetry diagnostics is needed. In the current study, proteomic profiling was used to examine sex-specific differences in age-matched C57BL6 mice on the blood proteome after radiation exposure, and the usefulness of development and application of biodosimetry algorithms using both male and female samples. Male and female mice between 9-11 weeks of age received a dose of total-body irradiation (TBI) of either 2, 4 or 8 Gy and plasma was collected at days 1, 3 and 7 postirradiation. Plasma was then screened using the SomaScan v4.1 assay for ∼7,000 protein analytes. A subset panel of protein biomarkers demonstrated significant (FDR < 0.05 and |logFC| > 0.2) changes in expression after radiation exposure. All proteins were used for feature selection to build predictive models of radiation exposure using different sample and sex-specific cohorts. Both binary (prediction of any radiation exposure) and multidose (prediction of specific radiation dose) model series were developed using either female and male samples combined or only female or only male samples. The binary series (models 1, 2 and 3) and multidose series (models 4, 5 and 6) included female/male combined, female only and male only respectively. Detectable values were obtained for all ∼7,000 proteins included in the SomaScan assay for all samples. Each model algorithm built using a unique sample cohort was validated with a training set of samples and tested with a separate new sample series. Overall predictive accuracies in the binary model series was ∼100% at the model training level, and when tested with fresh samples, 97.9% for model 1 (female and male) and 100% for model 2 (female only) and model 3 (male only). When sex-specific models 2 and 3 were tested with the opposite sex, the overall predictive accuracy rate dropped to 62.5% for model 2 and remained 100% for model 3. The overall predictive accuracy rate in the multidose model series was 100% for all models at the model training level and, when tested with fresh samples, 83.3%, 75% and 83.3% for Multidose models 4-6, respectively. When sex-specific model 5 (female only) and model 6 (male only) were tested with the opposite sex, the overall predictive accuracy rate dropped to 52.1% and 68.8%, respectively. These models represent novel predictive panels of radiation-responsive proteomic biomarkers and illustrate the utility and necessity of considering sex-specific differences in development of radiation biodosimetry prediction algorithms. As sex-specific differences were observed in this study, and as use of point-of-care radiation diagnostics in future mass casualty settings will necessarily include persons of both sexes, consideration of sex-specific variation is essential to ensure these diagnostic tools have practical utility in the field.

How does ionizing radiation affect amyloidogenesis in plants?

PURPOSE: Ionizing radiation is a harsh environmental factor that could induce plant senescence. We hypothesized that radiation-related senescence remodels proteome, particularly by triggering the accumulation of prion-like proteins in plant tissues. The object of this study, pea (Pisum sativum L.), is an agriculturally important legume. Research on the functional importance of amyloidogenic proteins was never performed on this species. MATERIALS AND METHODS: Pea seeds were irradiated in the dose range 5-50 Gy of X-rays. Afterward, Fourier-transform infrared spectroscopy (FTIR) was used to investigate changes in the secondary structure of proteins in germinated 3-day-old seedlings. Specifically, we evaluated the ratio between the amide I and II peaks. Next, we performed protein staining with Congo red to compare the presence of amyloids in the samples. In parallel, we profiled the detergent-resistant proteome fraction by ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS). Differentially accumulated proteins were functionally analyzed in MapMan software, and the PLAAC tool was used to predict putative prion-like proteins. RESULTS: We showed a reduced germination rate but higher plant height and faster appearance of reproductive organs in the irradiated at dose of 50 Gy group compared with the control; furthermore, we demonstrated more ß-sheets and amyloid aggregates in the roots of stressed plants. We detected 531 proteins in detergent-resistant fraction extracted from roots, and 45 were annotated as putative prion-like proteins. Notably, 29 proteins were significantly differentially abundant between the irradiated and the control groups. These proteins belong to several functional categories: amino acid metabolism, carbohydrate metabolism, cytoskeleton organization, regulatory processes, protein biosynthesis, and RNA processing. Thus, the discovery proteomics provided deep data on novel aspects of plant stress biology. CONCLUSION: Our data hinted that protein accumulation stimulated seedlings' growth as well as accelerated ontogenesis and, eventually, senescence, primarily through translation and RNA processing. The increased abundance of primary metabolism-related proteins indicates more intensive metabolic processes triggered in germinating pea seeds upon X-ray exposure. The functional role of detected putative amyloidogenic proteins should be validated in overexpression or knockout follow-up studies.

Estudo dos efeitos da radioterapia no tecido cardíaco e sua associação com o metabolismo energético / Study of the effects of radiation therapy in cardiac tissue and its association with energy metabolism

Durante o tratamento radioterápico para tumores localizados na região torácica, parte do coração frequentemente é incluída no campo de tratamento e pode receber doses de radiação ionizante, significativas em relação à terapêutica. A irradiação do coração é capaz de causar importantes complicações cardíacas ao paciente, caracterizadas por alterações funcionais progressivas cerca de 10 a 20 anos após a exposição do órgão. Devido ao seu alto grau de contração e grande consumo energético, o tecido cardíaco é altamente dependente do metabolismo oxidativo que ocorre nas mitocôndrias. Danos as estas organelas podem levar ao decréscimo da produção de energia, tendo um impacto direto sobre a performance cardíaca. Ainda, ao interagir com as células, a radiação ionizante pode gerar uma série de eventos bioquímicos que conduzem a uma resposta celular complexa, em que muitas proteínas parecem estar envolvidas. Tendo em vista tais conhecimentos, o objetivo do estudo foi avaliar o aspecto ultraestrutural do tecido cardíaco, a bioenergética mitocondrial e a expressão diferencial de proteínas após irradiação. Os ensaios foram realizados em amostras de tecido cardíaco de ratos Wistar irradiados com dose única de 20 Gy direcionada ao coração. As análise tiveram início 4 e 32 semanas após irradiação. A análise ultraestrutural foi realizada através de microscopia eletrônica de transmissão. A respiração mitocondrial foi mensurada em oxígrafo, a partir das taxas de consumo de oxigênio pelas fibras cardíacas. A identificação de proteínas diferencialmente expressas foi investigada através de duas técnicas proteômicas: 2D-DIGE (2-D Fluorescence Difference Gel Electrophoresis) e uma abordagem label-free seguida de espectrometria de massas. Os resultados mostraram que os efeitos tardios da radiação incluem a degeneração das mitocôndrias e das unidades contráteis do tecido cardíaco, disfunções na cadeia respiratória mitocondrial e expressão diferencial de proteínas...

During radiotherapy for tumors located at toracic region, part of the heart is often included in the treatment field and may receive a significant ionizing radiation dose comparing to the therapeutics. Heart irradiation is able to cause substantial cardiac complications to patient, characterized by functional progressive changes from 10 to 20 years after the exposure of the organ. Because of its high level of contraction and large energetic consumption, cardiac tissue is highly depending on oxidative metabolism which happens at mitochondrias. Damage to these organelles can lead to decreased energy production, having a direct impact on cardiac performance. Even when interacting with cells, ionizing radiation can generate a series of biochemical events that lead to a complex cellular response, in many proteins seem to be involved. Given this knowledge, the aim of the study was to evaluate the ultrastructural appearance of cardiac tissue, mitochondrial bioenergetics and differential expression of proteins after irradiation. The tests were performed on samples of cardiac tissue of rats irradiated with single dose of 20 Gy directed to the heart. The analysis started 4 to 32 weeks after irradiation. The ultrastructural analysis was performed by transmission electron microscopy. Mitochondrial respiration was measured in oxigraph from rates of oxygen consumption by cardiac fibers. The identification of differentially expressed proteins was investigated using two proteomic techniques: 2D-DIGE (2-D Fluorescence Difference Gel Electrophoresis) and a label-free approach followed by mass spectrometry. The results showed that the late effects of radiation include degeneration of mitochondria and contractile units of cardiac tissue, dysfunction in the mitochondrial respiratory chain and differential expression of proteins involved in energy metabolism of carbohydrates, lipids and phosphocreatine. In general, the study showed that the cardiac irradiation damages...