npj Microgravity最新文献

Our previous studies suggested that FLOWERING LOCUS (FT) can integrate microgravity signals into the photoperiodic flowering pathway in Arabidopsis. However, the exact mechanisms remain unclear. In this study, we carried out transcriptomic analysis of wild-type (WT), gigantea (gi) mutant, CONSTANS overexpressing (35S:CO), and transgenic plants expressing FT with the green fluorescent protein gene controlled by a heat shock-inducible promoter (pHSP:GFP;pHSP:FT, FG) grown on the Chinese space station in comparison with their ground controls. The findings revealed that transcriptional microgravity response signature was not only conserved across the GI-CO-FT module disruption genotypes and the WT, but also displayed GI-CO-FT module disruption specific associated responses. Transcription factors belonging to the ERF, bZIP, bHLH, and BES1 families were significantly overrepresented among the GCC- and CACGTG-elements across GI-CO-FT specific microgravity responsive genes, suggesting that disruption of GI-CO-FT module could influence plant response to microgravity through integration pathways.

Developing effective countermeasures against oral health risks is essential for long-duration space missions. This study evaluated the feasibility of performing restorative dentistry procedures in a microgravity environment. A parabolic flight campaign aboard the Airbus A310 was conducted through the ESA Academy Experiments programme. The campaign included 90 parabolas over 3 days, each providing ~22 s of microgravity. Two senior dentistry students performed 72 caries preparations and 36 composite restorations on artificial teeth in three environments: ground, microgravity, and steady flight. Accuracy was evaluated using computer-aided 2D image analysis for preparation errors and 3D scanning for restoration errors. Statistical analysis using two-way ANOVA revealed no significant impact of environmental conditions on preparation (p = 0.623) or restoration (p = 0.139) accuracy, although operator differences were observed. These findings indicate that microgravity does not significantly impair the accuracy of restorative dentistry procedures, highlighting the potential to expand dental treatment in space.

Microgravity affects cell growth and apoptosis. Using a random positioning machine, we previously found that simulated microgravity (SMG) suppresses total cell proliferation and induces apoptosis of in vitro cultured hepatocytes. Here, we report an interesting finding that SMG partially suspends these hepatocytes, forming large spheroids. Both attached and suspended cells can grow, but suspended cells exhibit reduced cell growth and apoptosis, implying dormancy. Mechanistically, attached but not suspended cells exhibit upregulated PI3K/AKT/mTOR pathway activity and downstream protein c-Myc. Knocking down c-Myc promotes, whereas overexpressing it suppresses, hepatocyte suspension under SMG, suggesting that the PI3K/AKT/mTOR pathway and c-Myc protect these cells from entering a dormant state upon SMG.

As space missions extend to the Moon and beyond, Bioregenerative Life Support Systems (BLSS) are vital for food, oxygen, and resource recycling in closed habitats. We examined the physiological, biochemical, and lipidomic responses of Chlorella vulgaris (CCALA 269) grown under simulated Earth gravity (1 g), Moon gravity (0.17 g), and microgravity (μg) using a 3D clinostat. Reduced gravity was associated with higher biomass, photosynthetic pigments, and antioxidant capacity. Cultures under lunar and microgravity showed up to 170% more chlorophyll and carotenoids, and 160% more polyphenols and antioxidant activity. Lipidomics revealed membrane remodeling, with higher galactolipids and triacylglycerols, suggesting adaptations to preserve membrane function and energy reserves. These responses indicate substantial physiological plasticity in C. vulgaris, suggesting its potential relevance for BLSS as a source of nutrient-rich biomass, oxygen, and antioxidants. Our results suggest its potential for space food and life support, and the need for further research under real partial gravity conditions.

Human space exploration is rapidly advancing, with long-term expeditions becoming more common. Long-term space missions introduce prolonged exposure to microgravity and ionizing radiation, which elicit stress responses throughout many organ systems. As the cerebrovascular system is responsible for regulating blood flow to the brain, it is imperative to understand the effects of the space environment on the cerebrovascular system. Cerebrovascular alterations are also linked to neurological diseases such as Alzheimer's Disease, Parkinson's Disease, glaucoma, and stroke. This systematic review evaluates the current literature to demonstrate that spaceflight conditions (actual or ground-based analogs) can lead to changes in the cerebrovascular system at the network, cellular, and molecular levels. These findings demonstrate differences and similarities between cerebrovascular alterations due to the space environment and neurological conditions, highlighting that the mechanisms behind the reversibility and readaptation to Earth following spaceflight could inform treatments of neurological disease.

We evaluated the impact of spaceflight on a microphysiologic model of calcium oxalate (CaOx) kidney stone disease. Proximal tubule epithelial cells cultured as confluent microtubules were exposed to CaOx crystals with or without potassium citrate (a potential countermeasure) to determine the impact on gene expression. Nine genes were differentially expressed in response to CaOx crystal exposure during spaceflight. This project presents the use of microgravity as a unique environment to study kidney pathophysiology.

Research on articular cartilage has primarily focused on athletes, particularly regarding increased metatarsal cartilage thickness in high-impact sports, with limited studies in military settings. This study examined Air Force Academy cadets, who experience unique mechanical demands on their hands. A total of 30 senior male cadets (age: 23.14 ± 0.51 years; height: 174.07 ± 3.14 cm; weight: 70.20 ± 6.63 kg) were evaluated based on their hand/wrist injury history, categorizing them into those with an injury history (IH; n,17) and non-injury history (NIH; n,13). Various assessments included body composition, hand grip strength, hand length, and ultrasonography, applying a validated tool (Michigan Hand Outcomes Questionnaire). Ultrasound measurements showed that the IH group had thicker cartilage than the NIH group in the index, ring, and little fingers, indicating the need for improved ergonomics in cockpit design and enhanced training protocols to mitigate injury risks among pilots.

Exposure to microgravity decreases bone volume and increases marrow fat, partly due to impaired BMSC osteogenesis and enhanced adipogenesis. Staphylococcal enterotoxin C2 (SEC2) can influence BMSC differentiation, potentially promoting osteogenesis. This study investigated SEC2's effects on bone loss and marrow fat in hindlimb suspension (HLS) mice and BMSC differentiation under simulated microgravity. Results showed SEC2 alleviated bone deterioration and reduced marrow adiposity, promoting osteogenic over adipogenic differentiation by activating ERK/β-catenin signaling pathways. SEC2 increased ERK phosphorylation and β-catenin nuclear translocation, with effects diminished upon β-catenin knockdown. These findings reveal a novel mechanism by which SEC2 modulates BMSC fate under microgravity, highlighting its potential as a therapeutic agent for preventing bone loss and marrow adiposity in microgravity conditions.

Surface extravehicular activity (EVA) is one of the most cognitively demanding actions that astronauts can execute. Decrements in cognitive performance present an important risk to crew safety, yet there is currently insufficient data to characterize the cognitive capabilities required for optimal surface EVA performance. Here, we conducted a cognitive task analysis with 15 astronauts and subject matter experts to characterize the cognitive demands of surface EVA tasks and to identify the risks associated with decrements in cognitive performance during surface EVA. The information gathered from this study identifies the specific cognitive capabilities that astronauts will need for future surface EVA and provides the foundation for (1) prioritized and targeted cognitive performance measurement, (2) EVA simulation design at varying levels of cognitive workload, and (3) the development of technologies that can inform NASA standards and guidelines and EVA planning for future exploration class missions.

Microgravity can exacerbate radiation-induced DNA damage response, suggesting that microgravity may increase the risk of tumor initiation and development. However, the specific mechanism is still unclear. This study used X-rays, protons, and carbon ions to simulate space radiation, and three-dimensional clinostats or hind limb unloading to simulate microgravity. It was found that simulated space radiation and/or microgravity promoted malignant transformation and tumor development of lung epithelial cells BEAS-2B, and the two factors showed a synergistic effect. The mechanism involves simulated space radiation and/or microgravity leads to changes in intracellular calcium ion concentration, affecting cellular signaling pathways, inducing the interaction between CAMK2G and ARRB1, and promoting ARRB1 nuclear translocation. ARRB1 nuclear translocation enhances CA9 transcriptional activity following simulated space radiation and/or microgravity exposure. In short, changes in intracellular calcium concentration play a crucial role in ARRB1 nuclear translocation and subsequent malignant transformation.