Among the physiological consequences of extended spaceflight are loss of skeletal muscle and bone mass. One signaling pathway that plays an important role in maintaining muscle and bone homeostasis is that regulated by the secreted signaling proteins myostatin (MSTN) and activin A. Here we used both genetic and pharmacological approaches to investigate the effect of targeting MSTN/activin A signaling in mice that were sent to the International Space Station. Wild type mice lost significant muscle and bone mass during the 33 d spent in microgravity. Muscle weights of Mstn -/- mice which are about twice those of wild type mice were largely maintained during spaceflight. Systemic inhibition of MSTN/activin A signaling using a soluble form of the activin type IIB receptor (ACVR2B) which can bind each of these ligands led to dramatic increases in both muscle and bone mass with effects being comparable in ground and flight mice. Exposure to microgravity and treatment with the soluble receptor each led to alterations in numerous signaling pathways which were reflected in changes in levels of key signaling components in the blood as well as their RNA expression levels in muscle and bone. These findings have implications for therapeutic strategies to combat the concomitant muscle and bone loss occurring in people afflicted with disuse atrophy on Earth as well as in astronauts in space especially during prolonged missions.

Harsh environmental conditions including microgravity and radiation during prolonged spaceflights are known to alter hepatic metabolism. Our studies have focused on the analysis of possible changes in metabolic pathways in livers of mice which experienced 30 days of spaceflight with and without an additional re-adaption period of 7 days compared to control mice on Earth. Utilizing shotgun mass spectrometry and label-free quantification we performed proteomic profiling to investigate mice livers from the spaceflight project xe2 x80 x9cBion-M 1 xe2 x80 x9d. No significant alterations in protein levels were observed between control mice liver and spaceflight mice which is possibly caused by insufficient fold change detection combined with high variances within the groups. In contrast our results show that more than a third of the quantified protein levels are altered comparing the liver proteome of mice with and without re-adaption time after their spaceflight. Proteins related to amino acid metabolism showed higher levels after re-adaption which may indicate higher rates of gluconeogenesis. Members of the peroxisome proliferator-activated receptor pathway reconstitute their level after 7 days due to a decrease in fold change which indicates decreased signs of non-alcoholic fatty liver disease. Moreover bile acid secretion regenerates on Earth due to reconstitution of related transmembrane proteins and elevated levels of the drug-metabolising enzymes belonging to the CYP superfamily decrease 7 days after the spaceflight. Thus our study demonstrates reconstitution of pharmacological response and early signs of non-alcoholic fatty liver disease recover within 7 days whereas glucose uptake should be monitored due to alterations in gluconeogenesis.

Genomic and proteomic characterization of the Aspergillus niger isolate JSC-093350089 collected from U.S. segment surfaces of the International Space Station (ISS) is reported along with a comparison to the experimentally established strain ATCC 1015. Whole-genome sequencing of JSC-093350089 revealed enhanced genetic variance when compared to publicly available sequences of A. niger strains. Analysis of the isolate xe2 x80 x9a xc3 x84 xc3 xb4s proteome revealed significant differences in the molecular phenotype of JSC-093350089 including increased abundance of proteins involved in the A. niger starvation response oxidative stress resistance cell wall integrity and modulation and nutrient acquisition. Together these data reveal the existence of a distinct strain of A. niger onboard the ISS and provide insight into the molecular phenotype that is selected for by melanized fungal species inhabiting spacecraft environments.

Omics analyses of RNA and protein isolated from heads of microgravity reared adult Drosophila.

Bone loss and immune dysregulation are among the main adverse outcomes of spaceflight challenging astronaut xe2 x80 x99s health and safety. However consequences on B cell development and responses are still under-investigated. Up to now most studies addressing these questions were performed using an amphibian species. Consequently we used advanced proteomics analysis of femur bone and marrow of mice flown for one month on board the BION-M1 biosatellite to determine whether extreme conditions encountered during a real spaceflight affect B cell development in mice and to examine reversibility of the effects upon return to Earth. Our data revealed that adverse effects on B lymphopoiesis were more marked one week after landing and that this phenomenon was associated with a 41% reduction of B cells in the spleen. Thus the effects of spaceflight persisted during at least one week after landing. These reductions may contribute to explain increased susceptibility to infection even if we confirmed that animals were able to mount a humoral immune response.

RR-1 is a validation flight to evaluate the hardware operational and science capabilities of the Rodent Research Project on the ISS. RNA DNA and protein were purified from liver tissues from RR-1 mice (female C57BL/6J 16wk old at time of launch). From each group two liver samples were collected and frozen immediately after euthanasia. The rest of the liver samples from each group were collected from frozen carcasses dissected post-flight. RNA-Seq whole genome and RNA BS-Seq (bisulfite sequencing) and proteomic expression profiling were performed. RNA extracted from these tissues was re-sequenced; these data are available as part of GLDS-168 (https://genelab-data.ndc.nasa.gov/genelab/accession/GLDS-168).

This study compares standard laboratory protocols for tissue freezing and storage with a simulation of the delayed processing of liver specimens and long-term storage protocols used during the Rodent Research-1 (RR-1) payload. Liver samples from twelve-week old female C57BL/6J mice (snap frozen vs. 25 min. slow-frozen and stored for 3 days vs. 1 year) received from the RR-1 project were processed for extraction of RNA DNA and protein. RNA-seq whole genome bisulfite sequencing and mass spectrometry proteomics were performed. These multi-omics datasets will help distinguish the effects of freezing and storage time that could confound the interpretation of the Rodent Research-1 datasets.

The Rodent Reasearch-1 National Lab (RR-1 CASIS) experiment was performed to study the effect of microgravity on muscle wasting. RNA DNA and protein were purified from RR-1 CASIS (the Center for the Advancement of Science in Space) liver samples. Groups included: Flight (FLT) dissected on-orbit (21 or 22 days after launch); age-matched Ground Controls (GC); and Basal Controls (BC euthanized at time of launch). RNA-Seq whole genome BS-Seq (bisulfite sequencing) and proteomic expression profiling were performed.

Life in spaceflight demonstrates remarkable adaptive processes within the specialized environments of space vehicles which are subject to the myriad of attending and unique environmental issues associated with orbital trajectories. To examine the adaptive processes that occur in plants in space leaves and roots from Arabidopsis seedlings that were grown from seed for 12 days on the International Space Station and preserved on orbit in RNAlater were returned to earth and analyzed using iTRAQ broad scale proteomics procedures.

To reveal outcomes of microgravity on molecular processes within the cellular environment we have employed a mass-spectrometry based proteomics approach. Proteomics analysis based on mass spectrometry allows for the relative quantitation of a large number of proteins concurrently and in a relatively unbiased manner. Mass spectrometry based proteomics can be rendered even more informative by addition of a labeling component to understand the dynamics of the changing protein content. In this study we utilized a combination of proteomics techniques namely label-free quantification and dynamic stable-isotope labeling by amino acids in cell culture (Dynamic SILAC) to characterize the microgravity stress response in primary cardiomyocytes.