Search Results (16)

Understanding the combined gravi-phototropic behavior of plants is essential for space agriculture. Existing single-axis clinostats and gel-based grow media provide limited simulation fidelity. This study developed a Cloud-enabled triple-axis clinostat with built-in automated aeroponic and artificial photosynthetic lighting systems for Earth-based simulation under Martian gravity ranging from 0.35 to 0.4 g. Finite element analysis validated the stability and reliability of the acrylic and stainless steel rotating platform based on stress, strain, and thermal simulation tests. Arduino UNO microcontrollers were used to acquire and process sensor data to activate clinorotation and controlled environment systems. An Arduino ESP32 transmits grow chamber temperature, humidity, moisture, light intensity, and gravity sensor data to ThingSpeak and the Create IoT online platform for seamless monitoring and storage of enviro-physical data. The developed system can generate 0.252–0.460 g that suits the target Martian gravity. The combined gravi-phototropic tests confirmed that maize seedlings exposed to partial gravity and grown using the aeroponic approach have a shoot system growth driven by light availability (395–400 μmol/m²/s) across the partial gravity extremes. Root elongation is more responsive to gravity increase under higher partial gravity (0.375–0.4 g) even with low light availability. The developed soilless clinostat technology offers a scalable tool for simulating other high-value crops aside from maize. Full article

Microgravity simulation is essential for studying particle dynamics in space-related applications where traditional gravitational effects are absent. This study presents a numerical investigation of particle behavior in a clinostat-driven microfluidic channel, aiming to simulate microgravity conditions. A computational model was developed in COMSOL Multiphysics to analyze the impact of channel size, particle diameter, and rotational speed on particle trajectories and establish sets of parameters for assuring microgravity conditions. The results revealed that stable microgravity-like conditions could be achieved within specific parameter ranges, e.g., larger channel radii requiring lower rotational velocities for particle suspension. However, the tendency for gravitational settling increased with particle size or under suboptimal rotational speeds. These findings provide insights into the effectiveness of clinorotation as a microgravity simulation method and establish a foundation for optimizing experimental designs in space research and biomedical applications. Full article

Recent studies have confirmed that melatonin and N6-methyladenosine (m6A) modification can influence bone cell differentiation and bone formation. Melatonin can also regulate a variety of biological processes through m6A modification. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) serves as a reader of m6A modification. In this study, we used the hindlimb unloading model as an animal model of bone loss induced by simulated microgravity and used 2D clinorotation to simulate a microgravity environment for cells on the ground. We found that hnRNPA2B1 was downregulated both in vitro and in vivo during simulated microgravity. Further investigations showed that hnRNPA2B1 could promote osteoblast differentiation and that overexpression of hnRNPA2B1 attenuated the suppression of osteoblast differentiation induced by simulated microgravity. We also discovered that melatonin could promote the expression of hnRNPA2B1 under simulated microgravity. Moreover, we found that promotion of osteoblast differentiation by melatonin was partially dependent on hnRNPA2B1. Therefore, this research revealed, for the first time, the role of the melatonin/hnRNPA2B1 axis in osteoblast differentiation under simulated microgravity. Targeting this axis may be a potential protective strategy against microgravity-induced bone loss and osteoporosis. Full article

Exposure to microgravity during spaceflight induces the alterations in endothelial cell function associated with post-flight cardiovascular deconditioning. PIEZO1 is a major mechanosensitive ion channel that regulates endothelial cell function. In this study, we used a two-dimensional clinostat to investigate the expression of PIEZO1 and its regulatory mechanism on human umbilical vein endothelial cells (HUVECs) under simulated microgravity. Utilizing quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis, we observed that PIEZO1 expression was significantly increased in response to simulated microgravity. Moreover, we found microgravity promoted endothelial cells migration by increasing expression of PIEZO1. Proteomics analysis highlighted the importance of C-X-C chemokine receptor type 4(CXCR4) as a main target molecule of PIEZO1 in HUVECs. CXCR4 protein level was increased with simulated microgravity and decreased with PIEZO1 knock down. The mechanistic study showed that PIEZO1 enhances CXCR4 expression via Ca²⁺ influx. In addition, CXCR4 could promote endothelial cell migration under simulated microgravity. Taken together, these results suggest that the upregulation of PIEZO1 in response to simulated microgravity regulates endothelial cell migration due to enhancing CXCR4 expression via Ca²⁺ influx. Full article

Muscle and skeleton structures are considered most susceptible to negative factors of spaceflights, namely microgravity. Three-dimensional clinorotation is a ground-based simulation of microgravity. It provides an opportunity to elucidate the effects of microgravity at the cellular level. The extracellular matrix (ECM) content, transcriptional profiles of genes encoding ECM and remodelling molecules, and secretory profiles were investigated in a heterotypic primary culture of bone marrow cells after 14 days of 3D clinorotation. Simulated microgravity negatively affected stromal lineage cells, responsible for bone tissue formation. This was evidenced by the reduced ECM volume and stromal cell numbers, including multipotent mesenchymal stromal cells (MSCs). ECM genes encoding proteins responsible for matrix stiffness and cell-ECM contacts were downregulated. In a heterotypic population of bone marrow cells, the upregulation of genes encoding ECM degrading molecules and the formation of a paracrine profile that can stimulate ECM degradation, may be mechanisms of osteodegenerative events that develop in real spaceflight. Full article

The hypothesis about the role of the cortical cytoskeleton as the primary mechanosensor was tested. Drosophila melanogaster oocytes were exposed to simulated microgravity (by 3D clinorotation in random directions with 4 rotations per minute—sµg group) and hypergravity at the 2 g level (by centrifugal force from one axis rotation—hg group) for 30, 90, and 210 min without and with cytochalasin B, colchicine, acrylamide, and calyculin A. Cell stiffness was measured by atomic force microscopy, protein content in the membrane and cytoplasmic fractions by Western blotting, and cellular respiration by polarography. The obtained results indicate that the stiffness of the cortical cytoskeleton of Drosophila melanogaster oocytes decreases in simulated micro- (after 90 min) and hypergravity (after 30 min), possibly due to intermediate filaments. The cell stiffness recovered after 210 min in the hg group, but intact microtubules were required for this. Already after 30 min of exposure to sµg, the cross-sectional area of oocytes decreased, which indicates deformation, and the singed protein, which organizes microfilaments into longitudinal bundles, diffused from the cortical cytoskeleton into the cytoplasm. Under hg, after 30 min, the cross-sectional area of the oocytes increased, and the proteins that organize filament networks, alpha-actinin and spectrin, diffused from the cortical cytoskeleton. Full article

Clinostats are instruments that continuously rotate biological specimens along an axis, thereby averaging their orientation relative to gravity over time. Our previous experiments indicated that low-speed clinorotation may itself trigger directional root tip curvature. In this project, we have investigated the root curvature response to low-speed clinorotation using Arabidopsis thaliana and Brachypodium distachyon seedlings as models. We show that low-speed clinorotation triggers root tip curvature in which direction is dictated by gravitropism during the first half-turn of clinorotation. We also show that the angle of root tip curvature is modulated by the speed of clinorotation. Arabidopsis mutations affecting gravity susception (pgm) or gravity signal transduction (arg1, toc132) are shown to affect the root tip curvature response to low-speed clinorotation. Furthermore, low-speed vertical clinorotation triggers relocalization of the PIN3 auxin efflux facilitator to the lateral membrane of Arabidopsis root cap statocytes, and creates a lateral gradient of auxin across the root tip. Together, these observations support a role for gravitropism in modulating root curvature responses to clinorotation. Interestingly, distinct Brachypodium distachyon accessions display different abilities to develop root tip curvature responses to low-speed vertical clinorotation, suggesting the possibility of using genome-wide association studies to further investigate this process. Full article

Mechanical unloading-related bone loss adversely harms astronauts’ health. Nevertheless, the specific molecular basis underlying the phenomenon has not been completely elucidated. Although the bone microvasculature contributes significantly to bone homeostasis, the pathophysiological role of microvascular endothelial cells (MVECs) in bone loss induced by mechanical unloading is not apparent. Here, we discovered that MC3T3-E1 cells could take up exosomes produced by MVECs under clinorotation-unloading conditions (Clino Exos), which then prevented MC3T3-E1 cells from differentiating into mature osteoblasts. Moreover, miR-92b-3p was found to be highly expressed in both unloaded MVECs and derived exosomes. Further experiments demonstrated that miR-92b-3p was transferred into MC3T3-E1 cells by exosomes, resulting in the suppression of osteogenic differentiation, and that encapsulating miR-92b-3p inhibitor into the Clino Exos blocked their inhibitory effects. Furthermore, miR-92b-3p targeted ELK4 and the expression of ELK4 was lessened when cocultured with Clino Exos. The inhibitor-92b-3p-promoted osteoblast differentiation was partially reduced by siRNA-ELK4. Exosomal miR-92b-3p secreted from MVECs under mechanical unloading has been shown for the first time to partially attenuate the function of osteoblasts through downregulation of ELK4, suggesting a potential strategy to protect against the mechanical unloading-induced bone loss and disuse osteoporosis. Full article

Suborbital spaceflights now enable human-tended research investigating short-term gravitational effects in biological systems, eliminating the need for complex automation. Here, we discuss a method utilizing KSC Fixation Tubes (KFTs) to both carry biology to suborbital space as well as fix that biology at certain stages of flight. Plants on support media were inserted into the sample side of KFTs preloaded with RNAlater in the fixation chamber. The KFTs were activated at various stages of a simulated flight to fix the plants. RNA-seq analysis conducted on tissue samples housed in KFTs, showed that plants behaved consistently in KFTs when compared to petri-plates. Over the time course, roots adjusted to hypoxia and leaves adjusted to changes in photosynthesis. These responses were due in part to the environment imposed by the encased triple containment of the KFTs, which is a requirement for flight in human spacecraft. While plants exhibited expected reproducible transcriptomic alteration over time in the KFTs, responses to clinorotation during the simulated flight suggest that transcriptomic responses to suborbital spaceflight can be examined using this approach. Full article

The necessity to include plants as a component of a Bioregenerative Life Support System leads to investigations to optimize plant growth facilities as well as a better understanding of the plant cell membrane and its numerous activities in the signaling, transport, and sensing of gravity, drought, and other stressors. The cell membrane participates in numerous processes, including endo- and exocytosis and cell division, and is involved in the response to external stimuli. Variable but stabilized microdomains form in membranes that include specific lipids and proteins that became known as (detergent-resistant) membrane microdomains, or lipid rafts with various subclassifications. The composition, especially the sterol-dependent recruitment of specific proteins affects endo- and exo-membrane domains as well as plasmodesmata. The enhanced saturated fatty acid content in lipid rafts after clinorotation suggests increased rigidity and reduced membrane permeability as a primary response to abiotic and mechanical stress. These results can also be obtained with lipid-sensitive stains. The linkage of the CM to the cytoskeleton via rafts is part of the complex interactions between lipid microdomains, mechanosensitive ion channels, and the organization of the cytoskeleton. These intricately linked structures and functions provide multiple future research directions to elucidate the role of lipid rafts in physiological processes. Full article

Gravi-morphoses affect the variability of plants and are the morphogenetic adaptation to different environmental conditions. Gravity-dependent phenotypic plasticity of gametophytes as well as gravi-sensitivity of moss protonemata in microgravity and simulated microgravity conditions are discussed. The moss protonema, a filamentous multicellular system, representing a juvenile stage of moss development, develops as a result of the elongation and division of the apical cell. This apical cell of the protonema is a unique object for research on moss gravi-sensitivity, as graviperception and gravitropic growth occur within the same single cell. Attention is focused on the influence of gravity on bryophyte ontogenesis, including the gravitropic reactivity of moss protonemata, gravi-sensitivity at the stage of leafy shoot development and sporogonium formation, gravity-influenced morphogenesis of apical cell budding, and gravity-dependent spiral growth patterns. The role of gravireceptors in the growth processes of mosses at the cellular level under microgravity conditions are being discussed, as well as the involvement of auxin transport, Ca2+-induced gravitropism and the cytoskeleton in gravitropic reactions. Full article

Bacterial behavior has been studied under microgravity conditions, but very little is known about it under lunar and Martian gravitational regimes. An Earth-based approach was designed and implemented using inclined clinostats and an in-house-developed code to determine the optimal clinorotation angular speed for bacterial liquid cultures of 5 RPM. With this setup, growth dynamics, phenotypic changes, and sensitivity to antibiotics (minimum inhibitory concentration (MIC) of two different classes of antibiotics) for three Escherichia coli strains (including uropathogenic) were examined under simulated micro-, lunar, and Martian gravities. The results included increased growth under simulated micro- and lunar gravities for some strains, and higher concentrations of antibiotics needed under simulated lunar gravity with respect to simulated micro- and Martian gravities. Clinostat-produced results can be considered suggestive but not determinative of what might be expected in altered gravity, as there is still a need to systematically verify these simulation devices’ ability to accurately replicate phenomena observed in space. Nevertheless, this approach serves as a baseline to start interrogating key cellular and molecular aspects relevant to microbial processes on the lunar and Martian surfaces. Full article

Mechanical unloading contributes to significant cardiovascular deconditioning. Endothelial dysfunction in the sites of microcirculation may be one of the causes of the cardiovascular degeneration induced by unloading, but the detailed mechanism is still unclear. Here, we first demonstrated that mechanical unloading inhibited brain microvascular endothelial cell proliferation and downregulated histone deacetylase 6 (HDAC6) expression. Furthermore, HDAC6 promoted microvascular endothelial cell proliferation and attenuated the inhibition of proliferation caused by clinorotation unloading. To comprehensively identify microRNAs (miRNAs) that are regulated by HDAC6, we analyzed differential miRNA expression in microvascular endothelial cells after transfection with HDAC6 siRNA and selected miR-155-5p, which was the miRNA with the most significantly increased expression. The ectopic expression of miR-155-5p inhibited microvascular endothelial cell proliferation and directly downregulated Ras homolog enriched in brain (RHEB) expression. Moreover, RHEB expression was downregulated under mechanical unloading and was essential for the miR-155-5p-mediated promotion of microvascular endothelial cell proliferation. Taken together, these results are the first to elucidate the role of HDAC6 in unloading-induced cell growth inhibition through the miR-155-5p/RHEB axis, suggesting that the HDAC6/miR-155-5p/RHEB pathway is a specific target for the preventative treatment of cardiovascular deconditioning. Full article

The effects of spaceflight, including prolonged exposure to microgravity, can have significant effects on the immune system and human health. Altered immune cell function can lead to adverse health events, though precisely how and to what extent a microgravity environment impacts these cells remains uncertain. Macrophages, a key immune cell, effect the inflammatory response as well as tissue remodeling and repair. Specifically, macrophage function can be dictated by phenotype that can exist between spectrums of M0 macrophage: the classically activated, pro-inflammatory M1, and the alternatively activated, pro-healing M2 phenotypes. This work assesses the effects of simulated microgravity via clinorotation on M0, M1, and M2 macrophage phenotypes. We focus on phenotypic, inflammatory, and angiogenic gene and protein expression. Our results show that across all three phenotypes, microgravity results in a decrease in TNF-α expression and an increase in IL-12 and VEGF expression. IL-10 was also significantly increased in M1 and M2, but not M0 macrophages. The phenotypic cytokine expression profiles observed may be related to specific gravisensitive signal transduction pathways previously implicated in microgravity regulation of macrophage gene and protein expression. Our results highlight the far-reaching effects that simulated microgravity has on macrophage function and provides insight into macrophage phenotypic function in microgravity. Full article

Gravity variation effects on plants provide definite changes. Normal Earth gravity (1G) and microgravity (µg) are possible variations for experimental purposes. On-board spaceflight microgravity experiments are rare and expensive, as the microgravity environment is an outstanding platform for research, application and education. A Clinostat was used for ground-based experiments to investigate the shoot morphology of maize plants at the Space Agency of Nigeria—National Space Research and Development Agency (NASRDA). A Clinostat device uses rotation to negate gravitational pull effects on plant growth and development. Maize was selected for this experiment because of its nutritional and economic importance, and its usability on the Clinostat. Plant shoot morphology is important for gravi-responses. Shoot curvature and shoot growth rate analyses were conducted on the shoots of a provitamin variety of maize. The seeds were planted into three Petri dishes (in parallel) in a wet chamber using a plant substrate—agar-agar. The experimental conditions were subject to relative humidity, temperature and light conditions. After 3 days of germination under 1G, two of the Petri dishes were left under 1G, serving as controls for shoot curvature and shoot growth rate analyses. The clinorotated sample was mounted on the Clinostat under: a fast rotation speed of 80 rpm, a horizontal rotation position and a clockwise rotation direction. The images of the samples were taken at a 30 min interval for 4 h. After observations, the shoot morphology of the seedlings was studied using ImageJ software. The grand average shoot angles and shoot lengths of all the seedlings were calculated following the experimental period to provide the shoot curvatures and shoot growth rates, respectively. The results show that the clinorotated sample had a reduced response to gravity, with 50.77°/h for the shoot curvature, while the 90°-turned sample had 55.49°/h. The shoot growth rate for the 1G sample was 1.25 cm/h, while that for the clinorotated sample was 1.26 cm/h. The clinorotated sample had an increased growth rate per hour compared to the counterpart 1G sample. These analytical results serve as preparation for future real-space experiments on maize and could be beneficial to the agriculture sector. Full article