Biological risks associated with space radiation and microgravity are major concerns for long-term space travel. Through a Systems Biology approach our previous NASA work has shown both TGF xce xb2 signaling pathways and miRNAs have a critical impact on defining health risks with and without space irradiation. We hypothesize that circulating microRNA (miRNA) signatures are driving microvascular disease and muscle degeneration associated with accelerating aging and will be enhanced by exposure to the space environment (radiation and microgravity). We investigated this hypothesis both in vivo and in vitro and test novel antagonist therapies to these miRNA signatures as countermeasures to reduce space radiation-induced health risks. A comprehensive Systems Biology approach was used to examine the influence by high atomic number by high (H) atomic number (Z) and energy (E) (HZE) irradiation. To simulate low-dose exposure due to galactic cosmic rays (GCR) we used the ions energy and doses determined by a NASA consensus formula of 7 different ions to represent GCR (referred to as GCR sim model). To simulate high-dose radiation exposure due to solar particle events (SPE) we used an acute dose of SPE simulated beam at 1Gy which has energies ranging from 50MeV to 150MeV. C57BL/6 wild-type mice were utilized for irradiation with our established simulated microgravity model (hindlimb suspension model) and an in vitro 3D microvasculature tissue model under simulated microgravity (clinostat) conditions will also be irradiated. To expand on the circulating miRNA signature determined from our preliminary data we determined a group of conserved miRNAs which are commonly being regulated in the majority of the organs and tissues throughout the host using our established techniques. MiRNA-sequencing on serum (before IR and at time of sacrifice) liver heart and muscle tissue for all radiation groups revealed the key circulating miRNA signature (consisting of multiple miRNAs) impacting disease risk. Collectively understanding of how whole body space radiation impacts microvascular and tissue degeneration through circulating miRNAs will greatly enhance health risk prognostication and provide possible new mechanisms for protection against space radiation.

Biological risks associated with space radiation and microgravity are major concerns for long-term space travel. Through a Systems Biology approach our previous NASA work has shown both TGF xce xb2 signaling pathways and miRNAs have a critical impact on defining health risks with and without space irradiation. We hypothesize that circulating microRNA (miRNA) signatures are driving microvascular disease and muscle degeneration associated with accelerating aging and will be enhanced by exposure to the space environment (radiation and microgravity). We investigated this hypothesis both in vivo and in vitro and test novel antagonist therapies to these miRNA signatures as countermeasures to reduce space radiation-induced health risks. A comprehensive Systems Biology approach was used to examine the influence by high atomic number by high (H) atomic number (Z) and energy (E) (HZE) irradiation. To simulate low-dose exposure due to galactic cosmic rays (GCR) we used the ions energy and doses determined by a NASA consensus formula of 7 different ions to represent GCR (referred to as GCR sim model). To simulate high-dose radiation exposure due to solar particle events (SPE) we used an acute dose of SPE simulated beam at 1Gy which has energies ranging from 50MeV to 150MeV. C57BL/6 wild-type mice were utilized for irradiation with our established simulated microgravity model (hindlimb suspension model) and an in vitro 3D microvasculature tissue model under simulated microgravity (clinostat) conditions will also be irradiated. To expand on the circulating miRNA signature determined from our preliminary data we determined a group of conserved miRNAs which are commonly being regulated in the majority of the organs and tissues throughout the host using our established techniques. MiRNA-sequencing on serum (before IR and at time of sacrifice) liver heart and muscle tissue for all radiation groups revealed the key circulating miRNA signature (consisting of multiple miRNAs) impacting disease risk. Collectively understanding of how whole body space radiation impacts microvascular and tissue degeneration through circulating miRNAs will greatly enhance health risk prognostication and provide possible new mechanisms for protection against space radiation.

BACKGROUND: Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation being microRNAs (miRNAs) small noncoding RNA that act as post-transcriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity a condition of weightlessness experienced by astronauts during space missions which could have a synergistic action on cells increasing the risk of radiation exposure. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of gamma-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover let-7i* miR-7 miR-7-1* miR-27a miR-144 miR-200a miR-598 miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles carried out on PBL of the same donors identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of Response to DNA damage is enriched when PBL are incubated in 1 g but not in MMG. Moreover some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. CONCLUSIONS/SIGNIFICANCE: On the whole by integrating the transcriptome and microRNome we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL.

BACKGROUND: Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation being microRNAs (miRNAs) small noncoding RNA that act as post-transcriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity a condition of weightlessness experienced by astronauts during space missions which could have a synergistic action on cells increasing the risk of radiation exposure. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of gamma-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover let-7i* miR-7 miR-7-1* miR-27a miR-144 miR-200a miR-598 miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles carried out on PBL of the same donors identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of Response to DNA damage is enriched when PBL are incubated in 1 g but not in MMG. Moreover some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. CONCLUSIONS/SIGNIFICANCE: On the whole by integrating the transcriptome and microRNome we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL.

['Cancer-causing genome instability is a major concern during space travel due to exposure of astronauts to potent sources of high-linear energy transfer (LET) ionizing radiation. Hematopoietic stem cells (HSCs) are particularly susceptible to genotoxic stress, and accumulation of damage can lead to HSC dysfunction and oncogenesis. Our group recently demonstrated that aging human HSCs accumulate microsatellite instability coincident with loss of MLH1, a DNA Mismatch Repair (MMR) protein, which could reasonably predispose to radiation-induced HSC malignancies. Therefore, in an effort to reduce risk uncertainty for cancer development during deep space travel, we employed an Mlh1+/- mouse model to study the effects high-LET 56Fe ion space-like radiation. Irradiated Mlh1+/- mice showed a significantly higher incidence of lymphomagenesis with 56Fe ions compared to γ-rays and unirradiated mice, and malignancy correlated with increased MSI in the tumors. In addition, whole-exome sequencing analysis revealed high SNVs and INDELs in lymphomas being driven by loss of Mlh1 and frequently mutated genes had a strong correlation with human leukemias. Therefore, the data suggest that age-related MMR deficiencies could lead to HSC malignancies after space radiation, and that countermeasure strategies will be required to adequately protect the astronaut population on the journey to Mars.']

Space radiations and microgravity both could cause DNA damage in cells but the effects of microgravity on DNA damage response to space radiations are still controversial. A mRNA microarray and microRNA microarray in dauer larvae of Caenorhabditis elegans (C. elegans) that endured spaceflight environment and space radiations environment during 16.5-day Shenzhou-8 space mission were performed. In our study wild type and dys-1 mutant strains of C.elegans endured four conditions during shenzhou-8 spaceflight mission including spaceflight static condition(ss) spaceflight 1-g centrifugal condition(sc) ground control condition(gc) and no-transport control. Limited to the quantity of worm samples we performed technical-repeat test but not sample-repeat test. Accordingly eight miRNA microarrays were performed.

Space radiations and microgravity both could cause DNA damage in cells but the effects of microgravity on DNA damage response to space radiations are still controversial. A mRNA microarray and microRNA microarray in dauer larvae of Caenorhabditis elegans (C. elegans) that endured space xef xac x82ight environment and space radiations environment during 16.5-day Shenzhou-8 space mission were performed. In our study wild type and dys-1 mutant strains of C.elegans endured four conditions during shenzhou-8 spaceflight mission including spaceflight static condition(ss) spaceflight 1-g centrifugal condition(sc) ground control condition(gc) and no-transport control. Limited to the quantity of worm samples we performed technical-repeat test but not sample-repeat test. Accordingly eight miRNA microarrays were performed.

Space radiations and microgravity both could cause DNA damage in cells but the effects of microgravity on DNA damage response to space radiations are still controversial. A mRNA microarray and microRNA microarray in dauer larvae of Caenorhabditis elegans (C. elegans) that endured spaceflight environment and space radiations environment during 16.5-day Shenzhou-8 space mission were performed. In our study wild type and ced-1 mutant strains of C.elegans endured three conditions during shenzhou-8 spaceflight mission including spaceflight static condition(ss) spaceflight 1-g centrifugal condition(sc) and ground control condition(gc). Limited to the quantity of worm samples we performed technical-repeat test but not sample-repeat test.Accordingly xef xbc x8csix miRNA microarrays were performed.

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 biomarkers 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.

Space radiations and microgravity both could cause DNA damage in cells but the effects of microgravity on DNA damage response to space radiations are still controversial. A mRNA microarray and microRNA microarray in dauer larvae of Caenorhabditis elegans (C. elegans) that endured space xef xac x82ight environment and space radiations environment during 16.5-day Shenzhou-8 space mission were performed. In our study wild type dys-1 mutant and ced-1 mutant strains of C.elegans endured four conditions during shenzhou-8 spaceflight mission including spaceflight static condition(ss) spaceflight 1-g centrifugal condition(sc) ground control condition(gc) and no-transport control. Limited to the quantity of worm samples we performed technical-repeat test but not sample-repeat test.Accordingly 12 mRNA microarrays were performed.