To understand the molecular mechanisms affected by spaceflight it is essential to achieve high quality sample preservation on-orbit for downstream gene expression analysis. However sample preservation protocols must also be compatible with available equipment and crew time. NASA s Rodent Research (RR) missions have used various methods for euthanasia carcass preservation and tissue preservation. This study extends the sample preservation study performed by GeneLab in GLDS-49 which examined conditions used for the RR-1 mission to include conditions used for multiple RR missions and is designed to help determine factors which may confound data analysis. To determine whether these various factors affect changes in gene expression this ground-based study generated gene expression profiles measured by RNAseq from the livers of 20-21 week-old female C57BL/6J mice. Multiple interacting factors were investigated: 1) To understand how euthanasia protocols affect gene expression when mouse carcasses are slow frozen mice were euthanized by either euthasol injection ketamine/xylazine injection or CO2 inhalation and carcasses slow frozen on dry-ice mimicking carcass preservation in the MELFI on the ISS. Carcasses were thawed and RNA extracted from livers; 2) To understand how carcass preservation protocols affect gene expression mice were euthanized with euthasol and carcasses preserved by flash freezing in liquid nitrogen slow freezing on dry ice or immersion in RNAlater following three-way segmentation. Carcasses were thawed and RNA extracted from livers; 3) To understand how tissue preservation protocols affect gene expression mice were euthanized with euthasol and livers dissected and processed immediately or preserved by flash freezing in liquid nitrogen slow freezing on dry ice or immersion in RNAlater. Liver samples that were processed immediately were homogenized in RLT buffer and then either immediately further processed for RNA extraction or were stored for 70 days at -80C post-homogenization in sample RLT buffer prior to RNA extraction.

Data from the NASA Rodent Research-1 (RR-1) mission showed that gene-expression levels in mouse livers are different depending on what tissue preservation protocol is used and that slow freezing is not an effective method for preserving signals in gene-expression data. In response to these and other observations the Rapid Freeze hardware was built for use on the International Space Station. The Rapid Freeze hardware freezes mouse tissues (Glovebox freezer) and whole carcasses (Cryochiller) at rates closely mimicking those attained with immersion in liquid nitrogen. Because this hardware will be used extensively on future rodent research missions it is crucial to understand whether or not it preserves signals in gene expression data in order to maximize the value of these rare and expensive spaceflight experiments. Therefore this study was designed with three goals: 1) To evaluate the temperature profile of the Cryochiller and Glovebox freezer cartridges (Rapid Freeze hardware) over time during mock on-orbit procedures; 2) To determine the freezing profiles of tissues and carcasses using Rapid Freeze hardware at both optimal and sub-optimal temperatures (to mimic on-orbit operations) compared with those frozen in liquid nitrogen (the laboratory gold standard) or frozen at -80 C (the current standard method); 3) To identify gene expression changes in a) tissues that were frozen via the Glovebox freezer and b) tissues dissected from whole or partial carcasses that were frozen via the Cryochiller versus tissues that were frozen via control methods (liquid nitrogen or -80C slow freeze) to assess how the Rapid Freeze hardware compares with laboratory gold standard practices and our current standard methods.

The objective of the Rodent Research-9 (RR-9) mission was to use mice to understand the molecular basis of phenomena that affect astronauts during long-duration spaceflight particularly visual impairment and joint tissue degradation. To this end a flight group (FLT) of 10 week-old male C57BL/6J mice were launched from Kennedy Space Center (KSC) on 8/14/2017 and housed in Rodent Habitats on the ISS for 33 days before being returned alive to Earth. After splashdown in the Pacific Ocean the animals were transported to Loma Linda University (LLU) for testing euthanasia and dissection on 9/18/2018. A Basal Control (BSL) was housed in standard cages at Kennedy Space Center (KSC) and euthanized one day after launch of the FLT animals (8/15/2017). Ground Control (GC) and Vivarium Control (VIV) studies were planned to commence at KSC approximately one-week after the conclusion of the flight experiments. However all the GC and VIV mouse studies at KSC had to be cancelled due to Hurricane Irma and potential adverse effects on the animal housing facility. The GC and VIV studies were therefore rescheduled and begun in May 2018. The GC was euthanized and dissected 6/18/2018 - 6/20/2018 while the VIV was euthanized and dissected 6/22/2018 - 6/23/2018. Because this resulted in a different cohort of mice being used for the GC and VIV controls as compared to the flight (FLT) and basal (BSL) groups two cohort controls were included in the study. The first Cohort Control 1 (CC_C1) was from the same cohort as the FLT and BSL animals and was sacrificed and dissected 4 days after the FLT group (9/22/2017). The second Cohort Control 2 (CC_C2) was from the same cohort as the GC and VIV animals and was sacrificed and dissected 2-8 days after the GC and VIV groups (6/24/2018 - 6/26/2018). The CC_C1 and CC_C2 groups were housed in standard cages and fed standard chow in contrast to all other groups which received Rodent Foodbars. To clarify the connections between treatment groups and animal cohorts the following group abbreviations are used in the sample metadata: Flight (FLT_C1); Basal (BSL_C1); Ground Control (GC_C2); Vivarium Control (VIV_C2) Cohort Control 1 (CC_C1); Cohort Control 2 (CC_C2). Upon dissection livers were preserved in liquid nitrogen and stored at -80 C before RNA was extracted libraries generated (stranded ribodepleted) and sequenced (target 60 M clusters at PE 150 bp).

Data from the NASA Rodent Research-1 (RR-1) mission showed that gene-expression levels in mouse livers are different depending on what tissue preservation protocol is used and that slow freezing is not an effective method for preserving signals in gene-expression data. In response to these and other observations the Rapid Freeze hardware was built for use on the International Space Station. The Rapid Freeze hardware freezes mouse tissues (Glovebox freezer) and whole carcasses (Cryochiller) at rates closely mimicking those attained with immersion in liquid nitrogen. Because this hardware will be used extensively on future rodent research missions it is crucial to understand whether or not it preserves signals in gene expression data in order to maximize the value of these rare and expensive spaceflight experiments. Therefore this study was designed with three goals: 1) To evaluate the temperature profile of the Cryochiller and Glovebox freezer cartridges (Rapid Freeze hardware) over time during mock on-orbit procedures; 2) To determine the freezing profiles of tissues and carcasses using Rapid Freeze hardware at both optimal and sub-optimal temperatures (to mimic on-orbit operations) compared with those frozen in liquid nitrogen (the laboratory gold standard) or frozen in at -80 C (the current standard method); 3) To identify gene expression changes in a) tissues that were frozen via the Glovebox freezer and b) tissues dissected from whole or partial carcasses that were frozen via the Cryochiller versus tissues that were frozen via control methods (liquid nitrogen or -80C slow freeze) to assess how the Rapid Freeze hardware compares with laboratory gold standard practices and our current standard methods.

Female C57BL/6CR mice were flown onboard STS-135 for 13 days and returned to Earth for analysis. Livers were collected within 3-4 hours of landing and snap frozen in liquid nitrogen. Liver tissue samples that were used for microarray analysis for GLDS-25 were provided to GeneLab. GeneLab extracted RNA added ERCC control spike-in to the samples and performed RNA-Seq analysis.

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 C57Bl6/J 16wk old at time of launch) including eight from the Flight group and eight from the Ground Control group. From each group two liver samples were collected and frozen immediately after euthanasia (Flight mice dissected on-orbit after total 37 days after launch Samples FLT-M21 M22 and corresponding Ground Control samples GC-M31,M32). An additional six samples from each group were collected from frozen carcasses dissected post-flight (Samples FLT-M25,M26,M27,M28,M29,M30 and corresponding Ground Control samples GC-M35,M36,M37,M38,M39,M40). RNA-Seq whole genome and RNA BS-Seq (bisulfite sequencing) and proteomic expression profiling were performed.

To understand the molecular mechanisms affected by spaceflight it is essential to achieve high quality sample preservation on-orbit for downstream gene expression analysis. However sample preservation protocols must also be compatible with available equipment and crew time. NASA s Rodent Research (RR) missions have used various methods for euthanasia carcass preservation and tissue preservation. This study extends the sample preservation study performed by GeneLab in GLDS-49 which examined conditions used for the RR-1 mission to include conditions used for multiple RR missions and is designed to help determine factors which may confound data analysis. To determine whether these various factors affect changes in gene expression this ground-based study generated gene expression profiles measured by RNAseq from the quadriceps of 20-21 week-old female C57BL/6J mice. Multiple interacting factors were investigated: 1) To understand how euthanasia protocols affect gene expression when mouse carcasses are slow frozen mice were euthanized by either euthasol injection ketamine/xylazine injection or CO2 inhalation and carcasses slow frozen on dry-ice mimicking carcass preservation in the MELFI on the ISS. Carcasses were thawed and RNA extracted from quadriceps; 2) To understand how carcass preservation protocols affect gene expression mice were euthanized with euthasol and carcasses preserved by flash freezing in liquid nitrogen slow freezing on dry ice or immersion in RNAlater following three-way segmentation. Carcasses were thawed and RNA extracted from quadriceps; 3) To understand how tissue preservation protocols affect gene expression mice were euthanized with euthasol and quadriceps immediately dissected and preserved by flash freezing in liquid nitrogen slow freezing on dry ice or immersion in RNAlater.

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. xc2 xa0RNA 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). xc2 xa0

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.