In recent years, the successful construction of tissues derived from established iPSCs has been disclosed, but it has been reported that the constructed tissues encounter problems of internal ...necrosis when their size increases. To solve this problem, a simulated microgravity device is used. However, the culture of early developing kidney cells using this device has not yet been reported. This study investigated whether developing kidney cells cultured in a simulated microgravity environment can differentiate into glomerular cells and renal epithelial cells.
The results showed that both mouse developing kidney cells cultured in simulated microgravity and static environment formed kidney spheroids. In static culture, ureteric bud and glomerular structures were not found. While ureteric buds, podocytes, PECAM-1 positive cell aggregates, and primordial vascular plexus were formed in the kidney spheroids in simulated microgravity culture. Moreover, the expression level of the PECAM-1 gene was significant in simulated microgravity culture as compared to that of static culture. These results indicate that simulated microgravity is effective for the differentiation of developing kidney cells.
•Early developing kidney cells were cultured under microgravity, and kidney spheroids were formed within 8 days.•The functional structures such as ureteric buds and glomerular-like tissues were formed within the kidney spheroids.•It has the potential to differentiate of the undifferentiated kidney cells into functional tissue structures.
Mechano-bioengineering of the knee meniscus Ma, Zhiyao; Vyhlidal, Margaret J; Li, David Xinzheyang ...
American Journal of Physiology: Cell Physiology,
12/2022, Letnik:
323, Številka:
6
Journal Article
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The meniscus is a fibrocartilaginous structure of the knee joint that serves a crucial role in joint health and biomechanics. Degeneration or removal of the meniscus is known to lead to a chronic and ...debilitating disease known as knee osteoarthritis, whose prevalence is expected to increase in the next few decades. Meniscus bioengineering has been developed as a potential alternative to current treatment methods, wherein meniscus-like tissues are engineered using cells, materials, and biomechanical stimuli. The application of mechanical stimulation in meniscus bioengineering has presented varied results but, for the most part, it has been shown to enhance meniscus-like tissue formation. In this review, we summarized literature over the last 10 years of various mechanical stimuli applied in bioengineering meniscus tissues. The role of individual loading types is examined, and the effects on engineered meniscus are evaluated on both molecular and tissue levels. In addition, simulated microgravity is highlighted as a new area of interest in meniscus engineering, and its potential use as a disease-driving platform is discussed. Taken together, with the increased understanding of the effects of mechanical stimulation on bioengineered meniscus tissues, the most suitable loading regime could be developed for meniscus tissue engineering and osteoarthritis modeling.
One of the hallmarks of microgravity-induced alterations in several cell models is an alteration in oxidative balance. Notably, male germ cells, sensitive to oxidative stress, have also been shown ...susceptibility to changes in gravitational force. To gain more insights into the mechanisms of male germ cells’ response to altered gravity, a 3D cell culture model was established from TCam-2 cells, a seminoma cell line and the only available in vitro model to study mitotically active human male germ cells. TCam-2 spheroids were cultured for 24 hours under unitary gravity (UG) or simulated microgravity conditions (SM), which was achieved using a random positioning machine (RPM). Apoptosis and necrosis analyses performed on the UG- and SM exposed samples revealed no significant differences in all of the cell death markers. Notably, the Mitosox assay revealed significant oxidation of mitochondria, after microgravity exposure, at least at this culture time. In the SM-treated samples, gene expression levels (evaluated by real-time PCR) of the main enzymes of the antioxidant barrier, GPX1 and NCF1, were reduced, indicating an influence of SM on mitochondrial function. Notably, the expression of HMOX, involved in the heme catabolism of mitochondrial cytochromes, was increased. The SOD, XDH, CYBA, NCF-2, TXN, and TXNRD genes were not affected. The ultrastructural analysis by transmission electron microscopy revealed that SM significantly altered TCam-2 spheroid mitochondria, which appeared swollen and, in some cases, disrupted. Indeed, mitophagy, or mitochondrial autophagy, appears to be more represented in the samples exposed to simulated microgravity. This result seems to be in line with the increase, mediated by the simulated microgravity, in the enzyme HMOX. All together, these preliminary data demonstrate TCam-2 spheroids’ sensitivity to acute SM exposure, strongly indicating a microgravity-dependent modulation of mitochondrial morphology and activity and encouraging us to perform further investigations on the chronical exposure to SM of TCam-2 spheroids.
Recent studies are elucidating the interrelation between sleep, cranial perfusion, and cerebrospinal fluid (CSF) circulation. Head down tilt (HDT) as a simulation of microgravity reduces cranial ...perfusion. Therefore, our aim was to assess whether HDT is affecting sleep (clinicaltrials.gov; identifier NCT02976168). 11 male subjects were recruited for a cross-over designed study. Each subject participated in two campaigns each comprising 3 days and 2 nights. Intervention started on the second campaign day and consisted of maintenance of horizontal position or -12° HDT for 21 h. Ultrasound measurements were performed before, at the beginning and the end of intervention. Polysomnographic measurements were assessed in the second night which was either spent in horizontal posture or at -12° HDT. Endpoints were sleep efficiency, sleep onset latency, number of sleep state changes and arousals, percentages of N3, REM, light sleep stages and subjective sleep parameters. N3 and REM sleep reduced by 25.6 and 19.1 min, respectively (
= 0.002,
= -0.898;
= 0.035,
= -0.634) during -12° HDT. Light sleep (N1/2) increased by 33.0 min at -12° HDT (
= 0.002,
= 1.078). On a scale from 1 to 9 subjective sleep quality deteriorated by 1.3 points during -12° HDT (
= 0.047,
= -0.968). Ultrasonic measurement of the venous system showed a significant increase of the minimum (
= 0.009,
< 0.001) and maximum (
= 0.004,
= 0.002) cross-sectional area of the internal jugular vein at -12° HDT. The minimum cross-sectional area of the external jugular vein differed significantly between conditions over time (
= 0.001) whereas frontal skin tissue thickness was not significantly different between conditions (
= 0.077,
= 0.811). Data suggests venous congestion at -12° HDT. Since subjects felt comfortable with lying in -12° HDT under our experimental conditions, this posture only moderately deteriorates sleep. Obviously, the human body can almost compensate the several fold effects of gravity in HDT posture like an affected CSF circulation, airway obstruction, unusual patterns of propioception and effects on the cardiovascular system.
Long‐term spaceflight can result in bone loss and osteoblast dysfunction. Frizzled‐9 (Fzd9) is a Wnt receptor of the frizzled family that is vital for osteoblast differentiation and bone formation. ...In the present study, we elucidated whether Fzd9 plays a role in osteoblast dysfunction induced by simulated microgravity (SMG). After 1–7 days of SMG, osteogenic markers such as alkaline phosphatase (ALP), osteopontin (OPN), and Runt‐related transcription factor 2 (RUNX2) were decreased, accompanied by a decrease in Fzd9 expression. Furthermore, Fzd9 expression decreased in the rat femur after 3 weeks of hindlimb unloading. In contrast, Fzd9 overexpression counteracted the decrease in ALP, OPN, and RUNX2 induced by SMG in osteoblasts. Moreover, SMG regulated phosphorylated glycogen synthase kinase‐3β (pGSK3β) and β‐catenin expression or sublocalization. However, Fzd9 overexpression did not affect pGSK3β and β‐catenin expression or sublocalization induced by SMG. In addition, Fzd9 overexpression regulated protein kinase B also known as Akt and extracellular signal‐regulated kinase (ERK) phosphorylation and induced F‐actin polymerization to form the actin cap, press the nuclei, and increase nuclear pore size, thereby promoting the nuclear translocation of Yes‐associated protein (YAP). Our study findings provide mechanistic insights into the role of Fzd9 in triggering actin polymerization and activating YAP to rescue SMG‐induced osteoblast dysfunction and suggest that Fzd9 is a potential target to restore osteoblast function in individuals with bone diseases and after spaceflight.
Schematic illustration of the effect of simulated microgravity (SMG)‐regulated Fzd9 on YAP nuclear translocation in rescue osteoblast dysfunction. The overexpression of Fzd9 regulates the phosphorylation of ERK and Akt, as well as induces F‐actin polymerization to form the actin cap, pressing the nuclei, and increasing the nuclear pore size, which then promotes nuclear translocation of YAP. Our study findings indicate that Fzd9 acted as a potential target to restore osteoblast functions in bone diseases and space flight.
Microgravity and radiation exposure-induced bone damage is one of the most significant alterations in astronauts after long-term spaceflight. However, the underlying mechanism is still largely ...unknown. Recent ground-based simulation studies have suggested that this impairment is likely mediated by increased production of reactive oxygen species (ROS) during spaceflight. The small Maf protein MafG is a basic-region leucine zipper-type transcription factor, and it globally contributes to regulation of antioxidant and metabolic networks. Our research investigated the role of MafG in the process of apoptosis induced by simulated microgravity and radiation in MC3T3-E1 cells. We found that simulated microgravity or radiation alone decreased MafG expression and elevated apoptosis in MC3T3-E1 cells, and combined simulated microgravity and radiation treatment aggravated apoptosis. Meanwhile, under normal conditions, increased ROS levels facilitated apoptosis and downregulated the expression of MafG in MC3T3-E1 cells. Overexpression of MafG decreased apoptosis induced by simulated microgravity and radiation. These findings provide new insight into the mechanism of bone damage induced by microgravity and radiation during space flight.
•Microgravity and radiation exposure-induced bone damage is one of the most alterations in astronaut.•Both MG and RA elevated osteoblast apoptosis and decreased the expression of MafG.•Apoptosis induced by MG and RA combined are more serious than by MG or RA alone.•Increased ROS level facilitates apoptosis and down-regulate the expression of MafG.•Overexpression of MafG counteracted the MG and RA induced apoptosis.
Static magnetic field is useful in processing materials with various microstructures. A self-designed gravity-assisted automatic docking device was used to study diffusion in liquid Al-Cu melts under ...various SMFs up to 22 T. SMF reduces the coefficient of interdiffusion (DAlCu) by damping the melt convection, which is more efficient with a horizontal SMF than a vertical SMF. A simulated microgravity is achieved when the SMF is greater than the critical 3 T. The simulated microgravity is in favor of growing a single α-Al dendrite in Al-Cu melt. The physical mechanism, which is called the diffusion-limited favored single crystal growth, is established. The present work provides a potential method in processing the single metallic crystal rapidly in the future.
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The biotechnology- and medicine-relevant fungus
Aspergillus niger
is a common colonizer of indoor habitats such as the International Space Station (ISS). Being able to colonize and biodegrade a wide ...range of surfaces,
A. niger
can ultimately impact human health and habitat safety. Surface contamination relies on two key-features of the fungal colony: the fungal spores, and the vegetative mycelium, also known as biofilm. Aboard the ISS, microorganisms and astronauts are shielded from extreme temperatures and radiation, but are inevitably affected by spaceflight microgravity. Knowing how microgravity affects
A. niger
colony growth, in particular regarding the vegetative mycelium (biofilm) and spore production, will help prevent and control fungal contaminations in indoor habitats on Earth and in space. Because fungal colonies grown on agar can be considered analogs for surface contamination, we investigated
A. niger
colony growth on agar in normal gravity (Ground) and simulated microgravity (SMG) conditions by fast-clinorotation. Three strains were included: a wild-type strain, a pigmentation mutant (Δ
fwnA
), and a hyperbranching mutant (Δ
racA
). Our study presents never before seen scanning electron microscopy (SEM) images of
A. niger
colonies that reveal a complex ultrastructure and biofilm architecture, and provide insights into fungal colony development, both on ground and in simulated microgravity. Results show that simulated microgravity affects colony growth in a strain-dependent manner, leading to thicker biofilms (vegetative mycelium) and increased spore production. We suggest that the Rho GTPase RacA might play a role in
A. niger
’s adaptation to simulated microgravity, as deletion of Δ
racA
leads to changes in biofilm thickness, spore production and total biomass. We also propose that FwnA-mediated melanin production plays a role in
A. niger
’s microgravity response, as Δ
fwnA
mutant colonies grown under SMG conditions showed increased colony area and spore production. Taken together, our study shows that simulated microgravity does not inhibit
A. niger
growth, but rather indicates a potential increase in surface-colonization. Further studies addressing fungal growth and surface contaminations in spaceflight should be conducted, not only to reduce the risk of negatively impacting human health and spacecraft material safety, but also to positively utilize fungal-based biotechnology to acquire needed resources
in situ
.
The dry immersion (DI) model closely reproduces factors of spaceflight environment such as supportlessness, mechanical and axial unloading, physical inactivity, and induces early increased bone ...resorption activity and metabolic responses as well as fluid centralization. The main goal of this experiment was to assess the efficacity of venoconstrictive thigh cuffs, as countermeasure to limit cephalad fluidshift, on DI-induced deconditioning, in particular for body fluids and related ophthalmological disorders. Our specific goal was to deepen our knowledge on the DI effects on the musculoskeletal events and to test whether intermittent counteracting fluid transfer would affect DI-induced bone modifications.
Eighteen males divided into Control (DI) or Cuffs (DI-TC) group underwent an unloading condition for 5 days. DI-TC group wore thigh cuffs 8-10 h/day during DI period. Key markers of bone turnover, phospho-calcic metabolism and associated metabolic factors were measured.
In the DI group, bone resorption increased as shown by higher level in Tartrate-resistant acid phosphatase isoform 5b at DI
. C-terminal telopeptide levels were unchanged. Bone formation and mineralization were also affected at DI
with a decreased in collagen type I synthesis and an increased bone-specific alkaline phosphatase. In addition, osteocalcin and periostin levels decreased at DI
. Calcemia increased up to a peak at DI
, inducing a trend to decrease in parathyroid hormone levels at DI
. Phosphatemia remained unchanged. Insulin-like growth factor 1 and visfatin were very sensitive to DI conditions as evidenced by higher levels by 120% vs. baseline for visfatin at DI
. Lipocalin-2, a potential regulator of bone homeostasis, and irisin were unchanged. The changes in bone turnover markers were similar in the two groups. Only periostin and visfatin changes were, at least partially, prevented by thigh cuffs.
This study confirmed the rapid dissociation between bone formation and resorption under DI conditions. It revealed an adaptation peak at DI
, then the maintenance of this new metabolic state during all DI. Notably, collagen synthesis and mineralisation markers evolved asynchronously. Thigh cuffs did not prevent significantly the DI-induced deleterious effects on bone cellular activities and/or energy metabolism.
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