Microgravity exposure as well as chronic muscle disuse are two of the main causes of physiological adaptive skeletal muscle atrophy in humans and murine animals in physiological condition. The aim of this study was to investigate at both morphological and global gene expression level skeletal muscle adaptation to microgravity in mouse soleus and extensor digitorum longus (EDL). Adult male mice C57BL/N6 were flown aboard the BION-M1 biosatellite for 30 days on orbit (BF) or housed in a replicate flight habitat on Earth (BG) as reference flight control. In this study we investigated for the first time gene expression adaptation to 30 days of microgravity exposure in mouse soleus and EDL highlighting potential new targets for improvement of countermeasures able to ameliorate or even prevent microgravity-induced atrophy in future spaceflights. Overall Design: C57BL/N6 mice were randomly divided in 3 groups: Bion Flown (BF) mice flown aboard the Bion M1 biosatellite in microgravity environment for 30 days; Bion Ground (BG) mice housed in the same habitat of flown animals but exposed to earth gravity; and Flight Control (FC) mice housed in a standard animal facility.

Spaceflight imposes the risk of skeletal muscle atrophy for astronauts. The understanding of muscle atrophy because of spaceflight is limited but continued efforts are essential for developing countermeasures of this effect. A distinct difference between spaceflight-induced muscle atrophy and other forms of atrophy is the additional effect of cosmic rays in outer space. To study spaceflight-induced muscle atrophy we performed two ground-based models of microgravity in a low dose radiation environment and studied transcriptional changes in rat soleus muscle using microarray technology.

Microgravity exposure as well as chronic muscle disuse are two of the main causes of physiological adaptive skeletal muscle atrophy in humans and murine animals in physiological condition. The aim of this study was to investigate at both morphological and global gene expression level skeletal muscle adaptation to microgravity in mouse soleus and extensor digitorum longus (EDL). Adult male mice C57BL/N6 were flown aboard the BION-M1 biosatellite for 30 days on orbit (BF) or housed in a replicate flight habitat on Earth (BG) as reference flight control. In this study we investigated for the first time gene expression adaptation to 30 days of microgravity exposure in mouse soleus and EDL highlighting potential new targets for improvement of countermeasures able to ameliorate or even prevent microgravity-induced atrophy in future spaceflights. Overall Design: C57BL/N6 mice were randomly divided in 3 groups: Bion Flown (BF) mice flown aboard the Bion M1 biosatellite in microgravity environment for 30 days; Bion Ground (BG) mice housed in the same habitat of flown animals but exposed to earth gravity; and Flight Control (FC) mice housed in a standard animal facility.

It is well established that microgravity exposure causes significant muscle weakness and atrophy via muscle unloading. On Earth, muscle unloading leads to a disproportionate loss in muscle force and size with the loss in muscle force occurring at a faster rate. Although the exact mechanisms are unknown, a role for Ca2+ dysregulation has been suggested. The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump actively brings cytosolic Ca2+ into the SR, eliciting muscle relaxation and maintaining low intracellular Ca2+ ([Ca2+]i). SERCA dysfunction contributes to elevations in [Ca2+]i, leading to cellular damage, and may contribute to the muscle weakness and atrophy observed with spaceflight. Here, we investigated SERCA function, SERCA regulatory protein content, and reactive oxygen/nitrogen species (RONS) protein adduction in murine skeletal muscle after 35-37 days of spaceflight. In male and female soleus muscles, spaceflight led to drastic impairments in Ca2+ uptake despite significant increases in SERCA1a protein content. We attribute this impairment to an increase in RONS production and elevated total protein tyrosine (T) nitration and cysteine (S) nitrosylation. Contrarily, in the tibialis anterior (TA), we observed an enhancement in Ca2+ uptake, which we attribute to a shift towards a faster muscle fiber type (i.e., increased myosin heavy chain IIb and SERCA1a) without elevated total protein T-nitration and S-nitrosylation. Thus, spaceflight affects SERCA function differently between the soleus and TA. This dataset derives results from the calcium uptake (spectrofluorometry) and Western blot assays.

Upon weightlessness and microgravity deleterious effects on the neurosensory and neurovestibular systems haematological changes and deconditioning of musculoskeletal cardiovascular and cardiopulmonary functions have been reported. In particular loss of muscle mass and strength are triggered by weightlessness in humans during space flights that is similarly observed as a result of physical inactivity conditions and aging on Earth. However skeletal muscle tissue is of paramount importance for health maintenance (e.g. being essential to locomotion heat production and metabolism). To better prevent or eventually treat microgravity-induced muscle atrophy its underlying mechanisms have first to be characterized in detail. Using cutting-edge quantitative proteomics the aim of the present study was therefore to get an in depth view of the molecular regulations triggered by space conditions in skeletal muscles of mice during the 30-day flight of the BION-M1 biosatellite. As muscles differing in their fiber type composition appear to respond differently to microgravity (see above) we characterized here the differential response of the soleus extensor digitorum longus and vastus lateralis muscles.

The objective of the Rodent Research-6 (RR-6) study was to evaluate muscle atrophy in mice during spaceflight and to test the efficacy of a novel therapeutic to mitigate muscle wasting. The experiment involved an implantable subcutaneous nanochannel delivery system (nDS; between scapula) which delivered the drug formoterol (FMT; a selective Beta-2 adrenoceptor agonist) over the course of time. To this end a cohort of forty 32-weeks-old female C57BL/6NTac mice were either sham operated. or implanted with vehicle or treatment-filled nDS and launched in two Transporters (20 mice per Transporter) on SpaceX-13 on December 15 2017. They were transferred to Rodent Habitats onboard the International Space Station (ISS) and maintained in microgravity for 29 days (N=20 Live Animal Return [LAR]) or >50 days (N=20 ISS Terminal). After 29 days the 20 LAR animals were returned live to back to Earth on January 13 2018. After splashdown the animals were ambulatory on-ground for ~4 days until all subjects were processed during one day of dissections. There were two Baseline groups of animals sacrificed (LAR Baseline & FLT Baseline; N=20; 40 animals; ~36 weeks old) at Kennedy Space Center (KSC; 12/9/17). A Ground Control group mimicked the Flight LAR group which was housed at KSC then shipped alive to Novartis facilities where both the LAR and LAR Ground Control groups were processed (~41 weeks old; 1/16/18). All were anesthetized with isoflurane blood samples were obtained by closed-chest cardiac puncture and the animals were euthanized by exsanguination and thoracotomy. The 20 ISS Terminal mice were anesthetized via intraperitoneal injection of ketamine/xylazine/acepromazine over the course of a four days of dissections (2/6/18 until 2/9/18; 53-56 days after launch; 44 weeks old at time of on-orbit dissections). Blood samples and euthanasia were conducted the same as LAR and Baseline. Following blood draw and hind limb dissection the ISS-terminal animal carcasses were wrapped in aluminum foil placed in a ziploc bag and placed in storage at -80C or colder until return. The ISS-terminal Ground Controls (at KSC) followed the same euthanasia timeline methods and preservation. The final processing of frozen ISS-terminal frozen ISS-terminal Ground Controls and frozen 0-day FLT baseline animals were completed at Houston Methodist Research Institute in Houston TX (5/21/18 until 5/24/18). GeneLab received samples of dorsal skin from only sham treated animals (no drug treated animals) from the following groups Flight: LAR (n=9) ISS Terminal (n=9); Ground Controls: LAR GC (N=9) ISS Terminal GC (N=10) LAR Baseline (n=10) ISS Terminal Baseline (n=6). Total RNA was extracted and sequenced at a target depth of 60 M clusters per sample (ribodepleted paired end 150).

Microarray Analysis of Space-flown Murine Thymus Tissue Reveals Changes in Gene Expression Regulating Stress and Glucocorticoid Receptors. We used microarrays to detail the gene expression of space-flown thymic tissue and identified distinct classes of up-regulated genes during this process. We report here microarray gene expression analysis in young adult C57BL/6NTac mice at 8 weeks of age after exposure to spaceflight aboard the space shuttle (STS-118) for a period of 13 days. Upon conclusion of the mission thymus lobes were extracted from space flown mice (FLT) as well as age- and sex-matched ground control mice similarly housed in animal enclosure modules (AEM). mRNA was extracted and an automated array analysis for gene expression was performed. Examination of the microarray data revealed 970 individual probes that had a 1.5 fold or greater change. When these data were averaged (n=4) we identified 12 genes that were significantly up- or down-regulated by at least 1.5 fold after spaceflight (p < 0.05). Together these data demonstrate that spaceflight induces significant changes in the thymic mRNA expression of genes that regulate stress glucocorticoid receptor metabolism and T cell signaling activity. These data explain in part the reported systemic compromise of the immune system after exposure to the microgravity of space.

Microgravity as well as chronic muscle disuse are two causes of low back pain originated at least in part from paraspinal muscle deconditioning. At present no study investigated the complexity of the molecular changes in human or mouse paraspinal muscles exposed to microgravity. The aim of this study was to evaluate longissimus dorsi and tongue (as a new potential in-flight negative control) adaptation to microgravity at global gene expression level. C57BL/N6 male mice were flown aboard the BION-M1 biosatellite for 30 days (BF) or housed in a replicate flight habitat on ground (BG). Global gene expression analysis identified 89 transcripts differentially regulated in longissimus dorsi of BF vs. BG mice (False Discovery Rrate < 0,05 and fold change < -2 and > +2) while only a small number of genes were found differentially regulated in tongue muscle ( BF vs. BG = 27 genes). Overall Design: C57BL/N6 mice were randomly divided in 3 groups: Bion Flown (BF) mice flown aboard the Bion M1 biosatellite in microgravity environment for 30 days; Bion Ground (BG) mice housed in the same habitat of flown animals but exposed to earth gravity; and Flight Control (FC) mice housed in a standard animal facility.

Upon weightlessness and microgravity deleterious effects on the neurosensory and neurovestibular systems haematological changes and deconditioning of musculoskeletal cardiovascular and cardiopulmonary functions have been reported. In particular loss of muscle mass and strength are triggered by weightlessness in humans during space flights that is similarly observed as a result of physical inactivity conditions and aging on Earth. However skeletal muscle tissue is of paramount importance for health maintenance (e.g. being essential to locomotion heat production and metabolism). To better prevent or eventually treat microgravity-induced muscle atrophy its underlying mechanisms have first to be characterized in detail. Using cutting-edge quantitative proteomics the aim of the present study was therefore to get an in depth view of the molecular regulations triggered by space conditions in skeletal muscles of mice during the 30-day flight of the BION-M1 biosatellite. As muscles differing in their fiber type composition appear to respond differently to microgravity (see above) we characterized here the differential response of the soleus extensor digitorum longus and vastus lateralis muscles.

The spaceflight experiment was carried out using male C57BL/10J mice (8 weeks old at launch). Wild type mice (n=3) were launched by Space Shuttle Discovery and housed on the International Space Station (ISS) for 91 days. They returned to the Earth by Space Shuttle Atlantis. But only one mouse returned to the Earth alive. Whole brain was sampled from the mouse killed by inhalation of carbon dioxide at the Life Sciences Support Facility of Kennedy Space Center within 3-4 hours after landing. After the spaceflight experiment the on-ground experiment was also carried out at the Advanced Biotechnology Center in Genova Italy. A mouse with the same species sex and age was housed in mice drawer system (MDS) which was utilized for the spaceflight (SF) mice for 3 months as the ground control (GC). Another mouse was housed in normal vivarium cage as the laboratory control (LC). Amount of food and water supplementation and environmental conditions were simulated as the flight group. After 3 months brain was sampled from one mouse in group GC and LC respectively. Comprehensive analyses of gene expression were performed in the right brain. Total of 4,000 genes were analyzed. The expression levels of 60 genes significantly changed in response to SF compared with LC and/or GC. The 15 and 16 genes were up- (> 2 folds) and down-regulated (< 0.5 folds) respectively following SF vs. GC. The levels of 58 genes were significantly altered by housing in MDS in space and/or on the ground. Forty seven and 11 genes were significantly up- and down-regulated vs. LC. Twenty seven out of these genes responded to caging in MDS both in space and on the ground. Further 31 genes were influenced by housing in MDS on the Earth. Responses of the characteristics of brain to long-term gravitational unloading were investigated in mice.