The purpose of the present study was to evaluate damage in brain and eye in a ground-based model for spaceflight which includes prolonged unloading and low-dose radiation. Low-dose/Low-dose-rate (LDR) gamma-radiation using 57Co plates (0.04 Gy) was delivered whole-body to mature 6-month old female C57BL/6 mice to simulate the radiation component. Anti-orthostatic tail suspension was used to model the unloading fluid shift and physiological stress aspects of the microgravity component. Mice were hindlimb suspended and/or irradiated for 21 days. Tissues were collected at 7 days 1 4 and 9 months following simulated microgravity. Herein we proposed to use omics-based molecular phenotyping approach for identification and characterization of genomic signatures in multiple organ system associated with low-dose radiation and simulated microgravity.

The purpose of the present study was to evaluate damage in brain and eye in a ground-based model for spaceflight which includes prolonged unloading and low-dose radiation. Low-dose/Low-dose-rate (LDR) gamma-radiation using 57Co plates (0.04 Gy) was delivered whole-body to mature 6-month old female C57BL/6 mice to simulate the radiation component. Anti-orthostatic tail suspension was used to model the unloading fluid shift and physiological stress aspects of the microgravity component. Mice were hindlimb suspended and/or irradiated for 21 days. Tissues were collected at 7 days 1 and 4 months following simulated microgravity. Herein we proposed to use omics-based molecular phenotyping approach for identification and characterization of genomic signatures in multiple organ system associated with low-dose radiation and simulated microgravity.

Plants exhibit a robust transcriptional response to gamma radiation which includes the induction of transcripts required for homologous recombination and the suppression of transcripts that promote cell cycle progression. Various DNA damaging agents induce different spectra of DNA damage as well as collateral damage to other cellular components and therefore are not expected to provoke identical responses by the cell. Here we study the effects of two different types of ionizing radiation (IR) treatment HZE (1 GeV Fe26+ high mass high charge and high energy relativistic particles) and gamma photons on the transcriptome of Arabidopsis thaliana seedlings. Both types of IR induce small clusters of radicals that can result in the formation of double strand breaks (DSBs) but HZE also produces linear arrays of extremely clustered damage. We performed these experiments across a range of time points (1.5-24 h after irradiation) in both wild-type plants and in mutants defective in the DSB-sensing protein kinase ATM. The two types of IR exhibit a shared double strand break-repair-related damage response although they differ slightly in the timing degree and ATM-dependence of the response. The ATM-dependent DNA metabolism-related transcripts of the DSB response were also induced by other DNA damaging agents but were not induced by conventional stresses. Both Gamma and HZE irradiation induced at 24 h post-irradiation ATM-dependent transcripts associated with a variety of conventional stresses; these were overrepresented for pathogen response rather than DNA metabolism. In contrast only HZE-irradiated plants at 1.5 h after irradiation exhibited an additional and very extensive transcriptional response shared with plants experiencing extended night. This response was not apparent in gamma-irradiated plants.

RAD51 a multifunctional protein plays a central role in DNA replication and homologous recombination repair and is known to be involved in cancer development. We identified a novel role for RAD51 in innate immune response signaling. Defects in RAD51 lead to the accumulation of self-DNA in the cytoplasm triggering a STING-mediated innate immune response after replication stress and DNA damage. Our data suggest that in addition to playing roles in homologous recombination-mediated DNA double-strand break repair and replication fork processing RAD51 is also implicated in the suppression of innate immunity. Thus our study reveals a previously uncharacterized role of RAD51 in initiating immune signaling placing it at the hub of new interconnections between DNA replication DNA repair and immunity. Overall design Gene expression analysis of WT and sh RAD51 HT1080 cells was carried out before and after 1 Gy of high LET Fe particle radiation.